DW144
Transcript of DW144
Heating and Ventlilati1lng
Contractors Association
--------------
DW154 ~(rilic(Iiofl for Plastics Ductwork
e ACKNOWLEDGEME TS
The HVCA records its appreciation and thanks to the many people and organi ations who gave advice and information during the preparation 0 f thi s specification and in pal1icular to those members offor the drafting panel who contributed tbeir time experience and knowledge
DW154 DRAFTING PANEL
Graham Handley (Chainnan)
Me) Clarke
Bemard Coates
John Howes
Me)vyn Sargent
Keith Elphick (Drafting Panel Secretary)
Gareth Keller (Ductwork Group Secretary)
(HVCA)
Heating and Ventilating Contractors Association
Esca House 34 Palace Court London W2 4JG
Tel 020-7313 4900 Fax 020~7727 9268
e-mail contacthvcaorguk website www hvcaorguk
First Edition 2000 copy 2000 HVCA
ISBN 0-903783-31-2
1
6 6
DW154 Specificathm for Plastics Ductwork
s Page
Foreword 3
co PART ONE - TECHNICAL INFORMATION TO BE PROVIDED BY THE DESIGNER Introduction
2 Standards 3 Components 6 4 Particular requirements 6
PART TWO - STANDARDS 5 Application 8 6 Ductwork classification and Air leakage 8 7 Materials 9 8 Ductwork construction and Joint sealing 9
PART THREE - RECTANGULAR DUCTS 9 Rectangular duct sizes 11 10 Construction 11
101 General 11 102 Longitudinal seams 11 103 Sheet jointing seams 11 104 Socket and spigot joints 11 105 Flanged joints 11 106 Expansion joints 12 107 Stiffeners 12
11 Fittings 12 111 Standardisation of fit1ings 12 11 2 Stiffeners 12 113 Split1ers 12 114 Turning vanes 12 115 Branches 12 116 Change shapes 12 PART FOUR - CIRCULAR DUCTS
12 Standard sizes 16 13 Construction 16
131 General 16 132 Sheet jointing seams 16 133 Socket and spigot joints 16 134 Flanged joInts 16 135 Stiffeners 17 136 Expansion Joints 17
14 PART FIVE - HANGERS AND SUPPORTS General 19
15 PART SIX - GENERAL Access I Inspection openings 22
16 Regulating dampers 22 17 Fire dampers and Intumescent sleeves 24 18 Flexible I Expansion joint connections 24 19 Protective finishes 27 20 Connections to bUilding openings 27 21 Discharge Exhaust terminal 27 22 Thermal insulation 28 23 Fire retardant finishes on plastic ductwork 24 Reinforcement of ducts with GRP laminate 25 Standard component drawings and abbreviations
4
~I-------~- --shy
28 28 31
bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull
DW154 SpaiicatiOll for Plastics Ductwork
PART SEVENmiddot APPENDICESmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotAppemiddotndixmiddotmiddotjmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotAmiddotjrieakagefroniductwork middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot49middotmiddotmiddotmiddotmiddotmiddot Appendix 8 Guidance notes for the Transport Handling and Storage of ductwork 54 Appendix C Fire retardant finishes 55 Appendix D Guidance notes for Inspection Servicing and Cleaning access
openings 56 Appendix E Bibliography 58 Appendix F Conversion tables 60
Table LIST OF TABLES _ PART TWO - STANDARDS
1 8Ductwork classification and Air leakage limits PARTTHREE - RECTANGULAR DUCTS
2 Minimum constructional requirements - Rectangular Un-reinforced UPVC and pp 13 3 Fastening centres Rectangular duct flange joints 13
PART FOUR - CIRCULAR DUCTS 4 Standard sizes 16 5 Fastening centres Circular duct Flange joints 17 6 Minimum constructional requirements shy Circular Un-reinforced UPVC 18 7 Minimum constructional requirements - Circular Un-reinforced PPS and PP 18
PART FIVE - HANGERS AND SUPPORTS 8 Hangers and Supports - Rectangular Horizontal Ducts 19 9 Hangers and Supports - Circular Horizontal Ducts 19
PART SIX - GENERAL 10 Minimum constructional reguirements - Rectangular GRP Reinforced ducts 30 11 Minimum constructional requirements - CirCUlar GRP Reinforced ducts 30 12 Standard Abbreviations 47
PART SEVEN - APPENDICES 13 Air leakage rates 50 14 Access requirements for inspection servicing and cleaning 57
LIST OF ILLUSTRATIONS 0 bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull u
Fig PART THREE - RECTANGULAR DUCTS 1-4 Cross joints 14 5-6 Stiffeners 14 7 Tie rod assembly 14 8 Hard and Easy bends 14 9 Turning vanes 15
PART FOUR - CIRCULAR DUCTS 10-12 Cross joints 17 13 Stiffeners 17
PART FIVE - HANGERS AND SUPPORTS 14-16 Support bearers 20 17-18 Vertical ducts supports 20 19-22 Arrangement of bearers and hangers 21
PART srx - GENERAL 23-25 Expansion joints 25 26-28 Flexible connections 26 29-33 GRP reinforced - Cross joints and Stiffeners 31 34 35
Linear Thermal Expansion 34 35
36-77 Typical Design Stress Standard component drawings - Rectangular 33
78-105 Standard component drawings - Circular 40 106-115 Standard component drawings - PlantEquipmentMiscellaneous 46
PART SEVEN - APPENDICES 116 Permitted leakage at various pressures 52
Example of a completed test sheet 53
5
DW154 Specijimrol1 for Plastics Ductwork
ART 1 4
bullbullbullbullbullbullbullbullbull 41
Technical information to be provided by the desmiddotg er to the plastics ductwork cont actor 42
1 INTRODUCTION 11 Thi specificalion relates to the manufa ture
and installation of rectangular and circular 43 ductwork constructed from plastics The selection of construction method is at the discretion of the manufacturer to conform with the performance requirements of the pecified 44 ductwork clas ification Sections 2-4 blow define the information to be provided by the designer
45 2 STANDARDS
21 Pressure classification (Table 1)
22 Leakage classification (Table 1) 46
23 Positive and Negative pressures (Table I)
24 Materials (Parr 2 Section 7)
25 Any special ystem requirements 47
3 COMPONENTS
31 Access and drainage points Number and location of access doors and drainage points
32 Regulating dampers Specification location and mode of opelatioll of all regulating dampers 48
33 Fire stops Stops to meet the requiremen ts of the Authority directly responsible for fire protection 49
34 Flexible joint connections Sp cification and location of any flexible conne tions eg plant or building expansion joint
PARTICULAR REQU REMENTS
Plastics material Type of plastic material from which the ductwork i to be manufactured and detail of ductwork to special requirements not within this specification
Environmental Env ironmental conditi ons inside and sULToundillg tJle ductwork
Airflow Design airflow volume for all mam ducts branches and air tenninals
Pressurevelocities Design air velocities and pressures for all main ducts principal branches and tenninals
External thermalacoustic insolation he extent and type of insulation to be
provided by others should be stated including full specification for application and installation
Spark testing U spark testing is required the designer shall identify land mark in the contract programme for testing to be undertaken ie manufactur installation corrunissionjng
Air leakage testing The extent of any air leakage testing if required While it shall be mandatory for highshypres ure ductwork (a defined in this specification) to be tested for air leakage iu accordance with the procedure set out in DWI43 A Practical Guide to Ductwork Leakage Testin2 no such te tin of Jaw-oro
mediam-pres Llr duct work is requjJmiddoted
Identification Details of colour coding or identification if required For furth r information see HVCA publication DWl44 Appendix B
Solvent~fomes
Details of design criteria used or adopted to avoid the trapping and discharge of liquid solvent fumes or gases
6
~--
DW154 Specificatio1l for Plastics Ductwork
410 Protective finishes (Part 6 Section J9) Detai Is and specification of any protective finishes
411 Fire retardant finishes (Part 6 Section 23) The extent and limits of protection for any fire retardant finishes on plastic ductwork (Specific references must be defined)
412 Controlssensing equipment Details of positions and fixing configuration of all sensors and test points to suit specialist contml and sensing equipment
413 Special supports (Part 5 Section 14) Details of any spanning primary secondary steelwork or special support requirements not specifically covered by Section 14
414 Attachment to building structure (Part 6 Section 20) Specific requirements for the junction of ductwork and associated components to opening hou1d be detailed and specified with the limits of responsibility defined
Tbe design and provision of penetrations and associated framings are outside the scope of this specification
415 Ductwork layout drawing Details of any special requirement$ relating to CAD scales etc It is common practice and cost effective for duclwork manufacturers to utilise their approved ductwork layout drawings as a basis of their manufacturing installation information by adding the necessary details to the same drawin2 Scales of 150 or smaller may preclude tJlis practice therefore larger scales might be more appropriate The final choice of manufacturing installation scales shall be left to the ductwork contractor
416 Other requirements Details of any requirements far the ductwork not in accordance with the provisions of tbis specification including any modified construction required to conform with any requirements cancerning external ductwork (See 53) or to meet the regulations of a local autbority or athcr controlling body
4 7
Clause
Reference to designer In consideration of the foregoing reference is also made to the designer in the following c1ausesshy
Page 52 8 53 8 106 12 1072 12 111 12 131 16 1352 17 136 17 141 19 144 19 145 19 147 20 152 22 161 22 1631 23 1634 23 171 24 173 24 174 24 181 24 182 27 191 27 211 27 222 28 223 2R 231 28 252 31 Appendix A 49 Appendix B 54 Appendix C 55 Appendix D 56
7
DW154 Spaijicllliflll for Plastics Ductwork
PAR 2 54
Standards
5 APPLICATION
51 This specification sets out minimum requirem nts for tbe manufaclure and in-tallation of ductwork for commercial and industrial fume extraction and exhaust 5y terns made from any of th material listed in Seclion 7 and being within the limit of ize andor material Ihickness speci led in Ihe relevant tables Normal ambient operating temperatures are assumed within the pressurevelocil limits and the limits of air leakage for the various pressur classes prescribed in Table 1
52 Thi specill alion is inlended to apply to ductwork handling fume-laden air which are polluted or is otherwise exceptional in respect of temperarure or humidity (including aturated air) for dllctwork wber the external
surface are exposed to a hostile environment The design construction installati n supports and finishes in such case should be giv n special consideration b the de igner in relation to tbe parti [lIar requir ments of each application
6
61
53 TIlis specification is sllitabl for ductwork expo ed to external atffio phere The designer will need to ~ive sp cift details of any special finish constlUction (See eetiar J9)
62
This specification i ba ed on duct operating environments of not less than - 100e and for
PVC (non GRP reinforced) nor exceeding 40degC UPVC reinforced wilh GRP not exceedin cr
600 e PPS and PP not exceeding 60deg FBPP reinforced witb GRP not exceeding 70degC Systems required to operate at temperatur outside those d tailed above aJthough outside of Ih scop of Ll)is specification are Dot precluded but the ductwork hould be designed from fi rst principle Ilaving regard for the physical mechanical and chemical properties of the material It mu~t be noted that the cOlTosive re i tance of all the above m terials will decrea e at temperatures approaching 5deg to looe below the parent materiaL beat distonion point Further guidance on temperatup effect is provided in Fig 34 Linear Tbennal
xpansion and Fig 35 Typical 0 ign Stres es for VC and PP
DUCTWORK CLASSIFICATION AND A R LEAKAGE
Classification and air leakage limits Duc work la sification and air leakage limitmiddot are eL out in Table 1
Compatibility with CEN The leakage fa tor u ed in able 1 for Classes A Band C ~u-e the ame as those for the cIa e similarly de ignated in th E Document Pr E 12237Pr L507
Table bullbull uctwork Class icati nand ir Leakage Limits (Reproduced from DWI144j
Ducl pressure class
1
Low-pressure -Medium-pressure -High-pressure
-I
I Class A Class B
Class C
Static pr sure limil Air I akage LimitMaximum air
litres per ltccnno per quarevelocity
Positive Negalive metre of duct surface areu
2 4 5 ~ -Pa Pa
f-m1s
0027 X pors500 10500 --1000 0009 x po6~750 20
0003 x pO652000 750 40
Where p is he differential pressure in pascals
Nole Tllls specification DWl54 onJy covers construction up to 1500 Pa
8
- - shy -~----
- shy
DW154 SpeciiCfllioll for Plastics Ductwork
63 Leakage at various pressures and other 110 mm to 600 mm dia (Dimensional rela tionships tolerances to DIN 8062) Applying the limits specified In Table 1 Appendix A (Table 13) sets out the permitted 74 PPS (Forms aailable) leakage at each of a serie of pressures up tu a maximum for each class Incloded in that 741 Extmded sheet in thickness 3 mm to Appendix is a graphical presentation of the 12 mm (Dimensional tolerance to pre urelleakage relationship DIN 53479)
DWl143 A Practical Guide to Ductwork 742 V series tube in sizes 1] 0 mrn lO 630 Leakage Testing provides detai Is of the basis mm dia and fittings in size I 10 mm for the leakage limits specified in Table 1 to 400 mm dia (Dimenional
tolerances DIN 53479) 64 Air leakage testing
Air Jeakage testing of low and medium 743 All PPS material used hall be pressure ductwork is not mandatory under compatible and comply with DIN tJlis specification Air kakage testing of high 4102 part B and SS 476 part 7 class pressure ductvork t mandatory under this 4 PPS material should not be used for specification and for details of testing external applications vithout suitable procedure refer LO DW143 A Practical Guide protection (See Part 6 section 19) to Ductwork Leakage Testing
744 It should be noted thal PP is not fully 7 MATERIALS compatible wilh PPS
71 Application 75 FBPP (Forms aailable) This specification applies to ductwork constructed from materials as defined below 7 51 Sheet in thickness 3 mm to 9 mm or equal Minimum material thickness is to be taken a a nominal thickness as Tables 267 7 52 Continuous roll form in thickness 2 10 amp 11 AJJ UPVC materials ued shall be mm to 4 mm low flammability selfextinguishing compatible and UV stable with pigment colour to RAL 7 53 This particular material is specifically 7011 and DIN 4802 B 1 designed to be externally reinforced
with GRP (See Section 24) 72 Types
The materials covered by thi specification are 76 UPVCGRP abbreviated herein as foIlowsshy This is a form of composite lamjnate used (UPVC) Unplasticised polyvinyl chloride where improved mechanical trengtb UV (PPS) Self eXlioguihing polypropylene stabilisatiolJ or fire retardence is required (PP) Polypropylene (GRP) Gla s reinforced plastic 77 UPVCIFOAMJGRP (FOAM) Rigid polyurethane self FBPPFOAMfGRP
extinguiShing foam This is a form of composite laminate used (FBPP) Fabric backed polypropylene sheet where insulation andor support is required for
special applications 73 UPVC (Forms available)
8 DUCTWORK CONSTRUCTION 731 Extruded sheet in thickness 3 mm to AND JOINT SEALING
12 mm (Dimensional tolerances to DIN 7748) 81 Ductwork construction
The election of longitudillal cross joint and 732 V series tube in sizes 110 mm to stiffener types within the criteria laid dOT1 in
1AOO mm dia and fittings in siz~ Part 3 amp 4 shall be used as a minimum standard
9
DW154 Spet((icatioll for Plastics Ductwork
82 Joint sealing and sealants 8226 The joint mu t be held in po ition ror at leamiddott 5
821 General minutes A jig should be The integrity of the ductwork used jf nece-ltsary to ensure depends on the successful applicatioll that no twisting force i of tbe conemiddot t jointing metbod appl ied to th joint during
the period 822 Solvent cementing
Solvent cementing a atisfactory 8227 Once made the joint method of jointing circular UPVC should not be exposed to socket anu spigot or leeve joints a undue force for eight certain solvent based cement horn shy hour Tb full strength of geneously bond the PVC surface the jOjJlt is not achieved in providing uitabl joints Solvent less than twenty-four cementing i not practicable with PP hours because of its hioh resi tanc to solvents The procedure recommended OTE SOLVENT CEMENT JOINTING by the cement manufacnJrer should METHODS ARE TOT RECOMshybe followed but the following points ME DED FOR RECTANGULAR are important DUCT SECTIONS
[N ALL CASES S ALA MATshy8221 Clearance between ocket ERlALS MUST BE APPLIED
and spigot must be STRICTLY IN ACCORDA CE minimal because of the WITH THE MANUFACTUR ~RS
lirnited gap filling propshy 11 STRUCTIO SAD OSHH ertie of the cement ASSESSMENT
8222 Inside edges of sockets and 823 Hot air welding utside edge of spigot VC and pp a be welded by
shouJd be lightly chamshy Llsing the hot ga Ifil1er rod meUlOd fered ltmd thoroughly cleaned described helow
8223 Mating urfaces should be 8231 The welding gas can be cleaned using a proprietary nitrooen or compressed air solvent cleaner to remove and shltlll b fIltered free grease and slightly etch the from suspended water oil surface vapour and particulate
matter 8224 The cement should be
applied a quickly a 8232 The filler rods shall be possible to the socket and made from material to r pigot over the full area of compatible with the matshythe mating surface are eriaJ being welded should be taken to avoid the use of excessive 8233 Butt weld joints shall be cement bevelled to an included
angle of 60deg to 90deg and 8225 The posi liolling of the joint where po sibl welds shall
mUSl be achieved immedshy be fully penetrated from iately after the cement i both ide of the work applied aJld surplus cement removed
10
DW154 Specificatiol for Plastics Ductwork
8234 The joint face and the filler rod surfaces must be clean and grease fre and preferably roughened b shyfore welding In particular any deposited filler rod that is charred mu t be scraped away before additional runs are added
8235 The numbers of runs of fi lIer rod shall be sufficient to give a thiekne s of era s section of the veld at least equal to the thiekn s of the sheet
8236 Where high frequency park testing i specified lhi shall be undertaken in accordance with tbe weldshying in tmction handbook
Note A full descriplion of welding method is given in the Welding Institut handboo entitled Data on Welding of Thennoplastic Relevant BS amp CE Standards are prEN 12814-1 amp 2 prE 13067 and prE 13100-1
824 Completion of compo ite laminate joints Following solvent ementing or hot air welding of joints campi tion of any specified external laminate shall
carried out to maintain thebe
825
integrity of the construction (S 8227)
Gaskets These can be fabricated from various materials in the form of a pre-formed roll she t or trip applied between opposing faces of fbnced ross joints It i a visable to select material r commended by th ga ket manufacturer for the pecific appucation intended
PART 3
Rectangula ucts
9 RECTANGULAR DUCT SIZES
91 This specification covers duct size up to a rnLltimum longer ide of I -00 mm Duct size with an a peet ralio greater than 4 I ar not recommended Although they offer no problems of construction they increase friclionaJ resi tance and the pos ibility of Dois
10 CONSTRUCTION
101 General Th minimum constructional requiJement r r UPVC and PPPPS un-reinforced are hown in able 2
102 Longitudinal seams Longitudinal seams should Dot be located at corners or in the underside of the duct
103 Sheet jointing seams Seams shall be joined by continuous filler rod hot air welding or by fl1sion Vi ldiug only other form of jointing are not acceptable
104 Socket and spigot joints Sock t and spigot joints shall be formed by purpoe made double cket pi ces 100 mm long and of the ame thiekne material as the duct welded into position on each standard length of duet forming 50 mm de p sockets prepared and ready for final jointing on site with filler [Od of the ame formulation used for prefabrication (See Table 2)
105 Flanged joints
1051 FJa ges Fabricated flanges shall b con tmeted u ing miniumum of 9 mm thick by 50 nun wide material of matching formulation depending on duel size as hown in Table 2 The flange hall be mounted true and square to the duct surface and w lded on both sides a 103 and Figs 3 4 Alternative con truction Illay be
11
DW154 Spedjicfltiotl for Plastics Ductwork
utilised for attacllment to plant or other equipment
1052 Drillings Drjllings shall be placed to permit clearance to tbe extel11al casing and any reinforcement of tbe ductwork for the application of fastening
1053 Fastenings For nonnaJ application bright zinc plated bolts nuts and vashers hall be Llsed in sizes and pitch centres shown in Tabl 3 Where special conditions prevail consideration of other material finishes such as stainless steel bolpounds nuts and washers may be used In all cases gasket materials as Section 825 shaLL be used
106 Expansion joints Wher the configuration of the ductwork does not provide for movement due to temperature change or where such movement is restricted by branches or attachmenL expansion joints should be specified by the designer (See Section 18 FlexibleExpansion joint connections)
It is the re ponsibilir-y of the designer to identify the positions of any necessary expansion joints hased upon design param ters for the individual systems (See Figs 23 to 25 34 amp 35)
Design ote xamples of expansion joints shown in Figs 23 to 25 are not suitable for movement exceeding 30 mm
107 StilJeners
1071 External stiffeners Shall be fitted as specified in Tables 2 amp 10 and Figs 5 amp 6
1072 I temal stiffeners The u e of internal stiffening or bracing shall be acceptable iJ deemed necesary and approved by the designer (See Fig 7)
11 FITTINGS
111 Standardisation of fiuings The terminology and descriptions of rectangular duct fittings a et out in Section 25 are recommended for adoption as standard practice to provide common terms of reference for desi crners quantity surveyor and ductwork contractors and for those using computer in ductwork design and fabrication
Bend are designated as hard or easy and the e terms as used herein have the folJowin o
meanings
Hard signifies rotation in the plane of tb longer side of the cross ection
Easy signiiies rotation in the plane of the shorter side of the cros section
An example iIlu trating these term ] given in Fig 8
Fitting are fabricated by cutting and welding sheet
112 Stiffeners Shall be as 107 and Tables 2 amp 10
113 Splitters Shall be as shown in Fig 41 and welded as 1003
114 ruing vanes Where square bends are required turning vanes as shown in Fig 9 hall be fitted
115 Branches When fitting branch ducts to a main duct care should be taken to ensure that the rigidity- of the duct panel is maintained in terms of tbe sti ffenillg criteria
116 Change shapes Where a change bape is necessary to acconUllOdate the duct and the cross- ectional area is to be maintained the slope haU not exceed 225deg 011 any side (See Figs 52 to 56) Where a change in shape includes a local reduction in duct cras - ectionaJ area the slope should not exceed ISO on any side and tbe reduction in area should not exceed 20 Where tceper angles are necessary due to ile
12
DW154 Spec([icatirJ1l for Plastics Ductwork
restucllOn splitters shall be provided Taper Transformation pieces from circular 10 square pieces reducers and transformation piec s or rectangular shall be made as long a shall be manufactured from the tbickl1 s of p sible and uJe angl ball be uot mor than material specified for the larger size ducl 225 (Fig 55)
loon Pa 1500 Pa
2 3 4 5 6 mm mm mm mm
3 socket amp spigot - - -or tlanged
as Figs 1 2 3 401 to 600 45 flanged 50 x 9 flat 1200 800
50 x 9 flat welded both sides a Fig 3 as Fig 5
601 to 1000 45 flnged 50 x 9 flat 800 600 50 x 9 flat welded both sides as Fig 3 as Fig 5
1001 to 1500 6 anged 75 x 9 flat 600 600 75 x 9 flat welded botb sides as Fig 3 as FieJ 5
or or 70 x 70 x 9 angle 50 x 50 x 5 angle
as Fig 4 welded both sides as Fig 6
N t For constructional operating temp rature limits refer to Part 2 Clause 54
Longer Pitch Bolt Size
Side max 2
mm 1m mm Up to 400 100 8 with washers 401-600 tOO 10 with washers
601middot1000 100 10 with wash rs 1001-1500 100 10 with oycrsized
washer
13
Table 2 inimum con tructional requi ments - rectangUlar nmiddotreinforce UPVC and pp
Joints Sliffeners Maximum spacinOLonger Side MillirnUlll She t between
Thickness Joint~S(iffi ners
mm Up to 400
DW154 SpedflCiltion for Plastics Ductwork
Cross joint - recta gular ducts
Fig 1 Socket and spigot joint (UPVC and PP)
Conlinuou weld joint on sile onlinuou- wcld
CT~r~T2
Fig 3 Flange joint (UPVC and PP)
ontinuou weld
Fig 2 Socket and spigot joint (UPVC only)
Fig 4 Flange joint (UPVC and PP)
S iffeners - rectangular ducts
Fig 5 Flat Fig6 Angle
Oatim wo]
Fig8 Bends - examples of hardTie rod assembly and easy
Hard
Fig7 With spacers Easy
4
DW154 Speci(uariml for Plastics Ductwork
Fig 9 Turning Vanes
HOWl G TYl AL EXAMPLE OF FOCI G
15
Ma vane length shy 615 mm
Example ofbraemg when V1IIle length exeeed max pennined Ahematively two banks of ncs fixmg the centre rail together at ] 50 mm nrrcs
U~_II---- fixed to dnct wall both CDds
bLEVATION
vane
Maximum distance between centrc oflUming vanes should [Jot exceed 60 mm pitch
DW154 SPCCijicllfiull for Plastics Ductwork
practice to provide common terms ofPA T4 reference for designers quantiry urveyor and
Circular Ducts
12 CIRCULAR DUCT SIZES Th duct sizes [n Table 4 have been selected from the ISO and C standard ranges as the 132 preferreod sizes
Table 4 Circular ducts shystandard extruded tube sizes
133 Extruded tube
ISO Standard Sizes (Nominal Diameter) 11
Wan Wall Thickness Thickness
mm mm mm mm 110 500 4022
I25160 600 50 I25200 630 60
225 25 700 60 13425250 800 63
280 900 70 315
23 23 80
355 1000
25 1250 104 400 32 1400 108 450 35
Note The above sizes are subject to normal manufactl1ring tolerances Other size may be available in varying wall Lhicknesses and subject to test and operational pressure
13 CONSTRue ION
13 General Tllis specification covers duct sizes up to a maximum diameter of 1500 mm The minimum constructional requirements for UPVC amp PPPPS un-reinforced ducts sball be as Tables 6 amp 7
ductwork contractors and tho e using computers in ductwork design and fabrication The requirements for circular duct fittings apply throughout the size ranges covered in this specification
Sheet jointing seams Seams shall be joined either by continuous fLiJer rod hot air welding or by fu ion welding Other forms of jointing are not acceptable
Socket and Sl)igot joints Socket and spigot joints shall be formed by purpose made double socket pieces 100 mm long and of the same thickness material as tJJe duct welded into position on each tandard length of duct forming 50 mm deep sockets prepared and ready for final jointing on ite with PVC adhesive andor fill r rod of the same formulation used for fabrication
Flanged joints
1341 Flanges abricated flanges shall be conshy
structed using minimum of 9 mm thick by 50 mm wide material of matching formulation depending on duct size as shown in Tables 6 amp 7 The flange shall be mounted true and square to the duct surfaces and welded OD both sides a 103 and Fig 12
1342 Drilliogs Drilling ball be placed to permit clearance to the external casing and any reinforcement of the ductwork
1343 Fastenings For normal application bright zinc plated bolts nuts and washers hall
16
For srualler diameters preformed fittings are available otberwise fitting are fabricated from segments of duct or sheet welded together
The terminology and description of circular duct tiltings as set Ollt in Section 25 are recommended for adoption as standard
be used in sizes and pitCh centres shown in Table S Wh re special conditions prevail consideration of other material finishes such as stain le steel bolt nuts and wasbers shall be u ed In all ca cs gasket materials as Seciion 825 shall be USed
DW154 Speciliwriml for Plastics Ductwork
135 Stiffeners
1351 External stiffeners Shall be fitted as specified in Tables 67amp 1 I and Fig 13
1352 Internal stiffeners The use of internal stiffening or bracing hall be acceptable if deemed neces ary and appn ved by the designer
f 36 Expansion joints Where the corrfiguration of the ductwork does not provide for movement due to temperature
Cross joints - circular ducts
change or where such movement is restricted by branches or attachments expansion joints should be fitted (See Section 18 Flexible Expansion joint connections)
It is the responsibiLity of the designer to identify the position of any necessary expansion joints based upon design parameters for the individual systems (See Figs 23 24 2534 amp 35)
Design Note Examples of expansion joints shown are not suitable for movement exceeding 30 mm
Fig 10 Socket and spigot joint (UPVC and PP)
ConLinuous weld joim on ite Ontinuous weld
crlr~l
Fig 12 Flange joint (UPVC and PP)
Continllous wcld
boil
Continuous weld or Solvelll cement
Solvelll ccmcnl joim on sile
Fig 11 Socket and spigot joint (UPVC only)
Stiffeners - circular ducts Table 5 Fastening centres shycircular duct flange jointsFig13 Flat
flat conljnlJou~ly welded Diameter Pitch Bolt Size
max
1 2 J 11
1 shy -~
mm mm mm Up to 600 100 8 with washers
601middot1000 100 10 with washers - ---I
1001middot1500 100 10 with oversized washers
1
Minimum offourfixings
17
DW154 Specifiiutiofl for Plastics Ductwork
Table 6 constructional quiremen s - circular unshy inforced U VC
Diameter Minimum Joints Stiffeners Maximum spa ~in r
Sheet between Thickness Jointsl tiffcners
1000 Pa 1500 Pa
1 2 3 4 5 6 UD mm mm mm mm
UO to 600 3 socket amp spigot as Figs 10 11
or fla ged Fig 12
601 to 1000 45 socket amp spigot 50 x 9 flat 2400 2400 as Figs 10 11 welded bo sides
or Oanged as Fig 13 as Fig 12
1001 to 1500 6 Hanged 75 x 9 flat 1200 1200 as Fig 2 welded both ides
as Fig 13
Applies 10 Tables 6 alld 7
Note 1 For constructional operating temperature limit refer to Part 2 luu 54 2 To allow for conicleration or extruded se lions or fabricated component the materia] tllicknes i hawn a nominal
Table 7 Minimu onstrucfional requirements shy circular un-reinforced PPS and
Diameter Minimum Joints Stiffcners Maximum pacio Sheet between
Thickness Join sStiffener 1000 Pa 150n Pa
I 2 3 4 6 mm m m mm
110 to 500 3 socket amp spigot as Fig 10 or flaoged as Fig 12
501 to 750 45 ocket amp spi~ot
as Fi 10 or Uanged as Fig 12
751 to 1000 6 tlanged 50 x 9 Oat UOO 12 0 as Fig 12 welded nth sides
as Fig 13 1 1 to 1250 6 flanged 75 x 9 flat 800shy 800
as Fig 12 welded both sides as Fig 13
1251to~ flangcd 75 x 9 Oat 600 600 as Fig 12 welded both sides
as Fig 13
18
DW154 Sped(icalirm for Plastics Ductwork
PARTS
Hangers an Suppo ts
14 GENERA
141 Supports are an e sentiaJ part of me ductwork system and their supply and in tallation are normally the responsibility of the ductwork contractor The principl s are a I-rvCA publication DWIl44 Part 6 Section 19 and should be read in conjunction with this document
Design Note Designers may pecify specific requirements wbich will supersede guidance given in DW144
142 Rectangular ducts abl 8 give the- minimum requirements for
hanger and supports for un-reinforced ductwork
143 Circular ducts Table 9 gives the minimum requirements for hangers and upports for uD-reinforced ductwork
144 Vertical d cts The design of supports for vertical duct is dictated by site condition and where practical duc hould be upported at 4000 mm interval or where tbey pa s through a floor (but n ver exceeding 4500 mm) see Figs 17 amp J8
145 External ducts Where ducts are external to buildings and may be ubject to wind loading support should be plac d so as to restrain ide tl1ruSt and should allow axial movement as neces ary It is the respon ibility of me de igner to calculate the effect of the particular prevailing condition and to define any special upport requirement
146 Expansion joints Support shall be designed to permit axial movement only and shall e provided on eitl1er ide of expansion joint
I 1shy
I~
mm -Jp to 400
401 to 600 601 to 1000
Table B Hangers and Supports - rectangular horizontal ducts
Hanger Bearer Drop Roll Formed Rod
Long r Side
Cbannel ~-shy ~
---shy
Maximum ~pacing
4 52 3 _ -c Fig 15 - Figs 14 15 16 amp 2J
shy
mmm mmmm 240025 x 25 x 16 40 x 20 x 15 8 240040x20x15 40x 20 x 15 10 240040 x 20 x 1~510 40 x 20 x 15
shy
I
40 x 40 x 15 40 x 40 x 15 24001001 to 1500 I 10
Table 9 Hangers and Supports - circular horizontal ducts
Longer Side Hanoer Split Clips Maximum spacing Drop Roll f-ormed and Wrap-round Rod ~hannel Hang r
2 3 4I Fig 1920 amp 22Fig I
mm mmmm mm mm 25 x 25 x 15 IIp to 355 8 40 x 3- --1-_ 2400
2400
2400 2400
70x 6
40 x 5 SOx 5
40 x 20 x 15 40 x 20 x 15 40 x 40 15
10 10 10
356 to 600 601 to 1000 1001 to 1500
19
DW154 Spccijicutioll for Plastics Ductwork
147 Protection specification Any special coatingpaint Unless otherwise stated all support shall be finishes for protection against hostile manufactured in material as specified in this environments shall be advised by the designer
SUPPORT BEARERS
~ 14 Flg16 Inverted profile
angle I ~lIed steel
channel (alternatives) Fig 15 Profile channel (alternatives)
TYPICmiddotAL VERTICAL DUCT SUPPORTS Flat bar clipStiffening frame Outline ofinsulation stiffening frame or tlanged joint (if applicable) or flanged joint
Stiffening framc or flanged Joint
~~-I ( ee notes 10) I
r--~ -++- ~--4==J===4~---
Fig 17 Vertical rectangular ducts Fig18 Vertical circular ducts
The support bearer which depending on ducti tructural opening size could be either channel or angle section may be ll1ilised in any of the following arrangementsshy
a) To support the underside of a flat bar clip in halves (circular)
b) To support the underidc of either the stiffening frame oftbe flanged joint ofaoy duct section
c) To support either a stiffening frame Or a flanged joint below nsing drop rod srudding
20
DW154 Spediraiml for Plastics Ductwork
Arrangement of bearers and hangers (to be read in conjunction with Table 8 amp 9
wbich list material sizes relative 10 duel izes)
KEY Limits refer to actual duct size - insulation is additional - Typical
attachmentv -Atta hment t strucUlrcI to strucUlrc
I I
I - Flat Bar
I - Drop rod or - utlinc of lllddmg In ulillwn (if
applicable)
Alternative 7 drop rod or rt------------ 1 studdmg q I
I I Rectangular
ii i n 1
Fig 21 Rolled or profiled bearer Limit oncFig 19 Wrap-round hanger Limit 55 DIA
V v Drop rod orAllernaUC 1 1 tudding
drop rod or 1
-- -- 1studding and elded bas 1
I I0 -_
Limit 355 DIA Frg 22 Split clips Limit 1500 DIAFig 20 Flat strap hanger amp split clips
21
DW154 Specification for Plastics Ductwork
6PA deElned in J62 appropriate to the airflow pressure acoustic temperature and corrosion
General
15 ACCESSl SPECTION OPENINGS
151 General These are for inspectionservici ng on 1y
HVCA publication DWIl44 Part 7 - General Section 20 sets out the requirements for access applicable to this specification
152 Cleaningmaintenance Designers shall take specialist advice and then stipulate their requirements for the periodic internal cleaningmaintenance of ductwork and of the consequent need for adequate access for specialist cleaning equipment including the size type and locationfrequency of the actual access openings required
Appendix D sets out guidance notes for the consideration of cleaning access and also makes reference to the HVCA publication TR 17 Guide to Good Practice Cleanliness of Ventilation Systems which covers the su~ject
in greater detail
Note A majority of in tallations in which plastic ductwork is used are considered to have a nigb operational risk potential and provision of access should address this
16 REGULATI G DAMPERS
161 General Balancing dampers and control dampers are elements inserted into an air di tribution system or element of an air distribution sy middottem Balancng dampers permit modification of the air resistance of tbe system and consequently cbanging of the airflow rate Control dampers control tlle airflow rate and may in addition provide low leakage closure of the airflow
The deigner shall specify damper locations taking into consideration that good design practice requires a minimum of five times the diameter or width of the shortest side of uninterrupted flow between plant connections and the damper and select the damper type as
characteristics
1611 Balancing damper To achieve the required distribution of air in the ductwork system at inlets andor outlets for [hi purpose the damper blades are set and Jocked manually in position between fully open and fully closed
1612 Control damper To secure dynamic control of the air now in the ductwork system In thi function the damper will always be power actuated and may require to be modulated between fully open and fully closed and to be capable of taking up any position between these extremes In the fully open position the damper should have a minimum pressure drop In the fully closed position it will not necessarily achieve a complete shut off
162 Types of airflow control dampers Airflow dampers of various types are available for specific purposes as follows
1621 Single - blade dampers Single-blade dampers shall consist of a si ngle pi voted blade cOlllained withjn a casing or section of ductwork The blade shall be adjustable tbmugh a nominal 90 angle by means of a quadrant or similar operating mechanism Where automatic control of the damper is required the spindle shall be extended to enable a powered actllator to be mounted
Single-blade dampers shall have a maximum duct width of 400 nUll and a maximum duct height of 400 mm for rectangular ducts and for circular ducts a maximum diameter of 400 mm
1622 Multi-blade dampers Multi-blade dampers shall consist of a number of pivoted blades contained within a casing The blades shall be
22
DW154 Sedicalirm for Plastics Ductwork
adju table through a nominal 90deg angle simultaneously by intershyconnected linkage or gears connected to a quadrant or similar operating mecbanism Where automatic control of a damper is required a spindle shall be extended to enable a powered achlator to be mounted
There is no restriction on the size of duct in which multi-blade dampers or damper assemblie may be u ed Where dampers are required for blade lengths in excess of 750 mm the blades should be suitably reinforced or supponed 0
individual damper blade should exceed 200 mm in width
1623 Iris dampers Lris dampers shall consist of a nUlllber of radialty interconnected blades which open or close within a casing with duct COlll1cctions The blade shall be simultaneously adjusted by a quadrant or similar operating mechanism
Iris dampers shall be installed as specified by the manufacturers operating and installation instructions where the product is unidirectional with regard to airflow
lris dampers are available for circular ducts only in diameters up to 250 mm (it should be noted that the damper casin i appro)(imately twice the diameter of the duct)
1624 Backdraught dampers Air pressure operated uni-directional rectangular (single or multi-blade) with adapters if fitted to circular ducts
1625 Slide and blast gate dampers A damper [lsed as a shut off facility with an externaJ Lide bousing allowing the blade configuration to be fuJly inserted to fully extended for maxiDlUlll air flow
163 Construction
1631 Materials All products shall be protected against cOHosion as necessary and supplied in a fully finished condition as specified by the designer
1632 Dampers used in low and medium pressure systems The following recommendations apply to dampers forming an integral part of ducrwork with pressure classifications A and B air leakage limits
The dampers shaH be constructed to minimise distortion and prevent jammin in operation Th blade shall be sufficiently rigid to minimise movement when in the locked pOSitiOLl
The blades shall be securely fixed to the operating mechanism All balancing dampers shall have a locking device located on the outsid of the case and shall giv clear indication of the actlwl blad position All penetrations of the duct shall be fitted with suitable seals where necessary
1633 Dampers used in high pressure systems Regulatino- dampers used in duc[work sy tems to pressure cJassification C shall meet tbe construction requireshyments specified in 1631 and 1632 with operating mechanisms out of the air-stream
1634 Proprietary types of damper The use of any specific type of proprietary damper shall be confirmed by the designer In all cases proprietary dampers shall meet the relevant requirements of thi specification
1635 Damper casings Duct damper casings hall be constructed to meet th mllllmum
23
DW154 SpeciJimlioll for Plastics Ductwork
leakage Iim its sp cified for th c1uctwork ystem to which tbey are installed
In order to apply the square metre leakage calculatio as detailed in DW143 A Practical Guide to Ductwork Leakage Testing the reference casing area ball be taken as the perimeter ize of lh damper IDultipli d by the equi alent length of Imetr eg an 800 mm x 400 mm duct damper hall have a surface area for casillg leakag p donnan calculated as follow (2 x 08) + (2 x 04 x I
=24m2 casing area
Other pelforlllance ancl rating test methods for damp f and valves are specified in ISO 5129 and BSIE 1751 and are referenced belm a) Leakage past a closed damper
alve BSIE 1751 b) low ratepre sure requirement
characteri t cs BSIE 1751 c) Operational torque le ring
BSEN 1751 cl) Thermal transfer testing
BSIEN 17 I e) Reg nerated sound power levels
ISO 5129
164 Installation Dampers shall be imaalled in accordance will) any re Ievant ISO EN or British Standard 10 aJ bUT lcling regulation and national code of practice as well as the manufacturers recommendations
17 FIRE DAMPERS AND INT MESCENT SLEEVES
171 General Damper or sleeves arc requiTed on duct y~telll where the designer has -tjpulated the
duct wiU penetrate a fire compartment in the majority of application tbermopla ti ductwork is ugtecl where contamlDated corro ive or otherwise exceptional fumes are concerned it is preferable to use tire damp r which are externalJy mounted ie of the intmnescent operated crush typ
24
72 Fit-e rating The damper assembly should have a fUT
resi tance ratin o equal to that of the fir ban-jer it penetrate and ball be fire tested and rated to the timetemperature curv of B 476 Part 20 and 22
173 Intumescent sleeve At the time of writing this specification qualified test results were available for rectangular dampers and circular dampers up to 55 mm diamet r Manufacture have indicated that they are able t provide speci fications for other size and diameters This infonnation should be confirmed b th de igner Various type are available includino
tho e incorporating ruechanical closing plate and those operated anI by expanded iJllUme c nt media
In all ca es fire damp rs and intnmeBcen leeves shall be supplied and in taUed in
accordance with the manufacturer iJlStructioos and COSHH a essm nt
174 Other types Fire dampers of mious types are availabl for specific purpose~ ee HVCA publication DW144 The de igner should )lot (hat materials for con lt1Jction bould be uitablc for the par1icular application
ALL C SES FIRE DAMPERS AND fNT MESCENT SL _VES SHALL HE S PPLTED AND INSTALLED IN A ORDA CE WITH Tf--IE MANUshyPACTURERS STRUCTTONS AND COSHH ASSESSMENT
18 FLEXIBLEEXPANSION dOINT CONNECTIONS
181 General ploperties Tbe material u ed for flexibleexpan ion iojnt~
mu t meet the design r requirements for temperature air pressllrelfe resistance applicable to pl astic duct sy tem vibration and noi e br akout when incorporated into a jointconnection and shall comply ith lh standard of air-tigbtne specifi cl for the duct work sy tem of which it fOlms part (See Figs 23 24 5 26 27 amp 28 for typical con truclion clelai Is
DW154 SJecilimtol for Plastics Ductwork
Expansion joints
Fig23 Moulded bellows type (rectangular and circular)
Fig24
~F aiblc sleeve
__ liding sleeve
~~~~
Sleeve type (circufar)
Fig 25
AIRFLO
COnlinuou~
weld~
Flexible Iceve
PV A HOWN pp SE BACKING FLATS AS FIG 2
Sliding lee c Co1linuou
weld
Flanged sleeve (rectangular and circular)
25
DW154 Specificatiol for Plastics Ductwork
Flexible con ections
Fig 26 Flexible sleeve with clips (UPVC and PP)
--__ Flexible I eve
I
I
I CODn clioD to plant ~
Band clip
Fig27 Welded flexible sleeve (UPVC only)
Plastic)sed PVC slceve ~-- onll11uo1sly welded
onrreclion to planl ~
Fig28 Flanged flexible connection (UPVC and P )
t sp dally moulded flexible flanged connCClitlll
boil
C)nneclion to plant ~
26
DW154 Specificotiol for Plastics Ductwork
182 LOClt1tion Flexible joint are typicltllly lIsed at building expansion joint and fan inletsoutlets Any others required should be indicated on the de ign drawings Care should be taken to maintain alignment across jointsconnections
183 Length Flexible Jomts shall be kept as short as pra middottieable above a minimum eft ctive length of SO mm In no ca e shall a flexible joint exceed 250 mm in lengtb
184 Connections to rectang a ducts With flanged rectangular connections Ule tlexible material shall be held in pLace with flat pIa tic strip of not less U1an 6 mm thick ltlttached to the flanges using uitabJe fixings The more heavy weight type of fleAible mateLial may also be obtained formed into a channel ection with corners fitted to give a neat air tight j int For pigot connections the Be ible material shall b held in place with flat pIa tic trips n t less than 6 mm thick
t 85 Connections to circular ducts With tlanged circular connections the flexibl material shall be held in place with flat plastic backing strips or proprietary clip bands with screw or toggle fast ners
186 Welded flexible connections (Rectangular and Circular) Where the parent and llexibl material are from imilar ba ed products they can be joined to the duct u ing the welding method described in Section 823
19 PROTECT VE FINISHES
191 nles otherwise stated all ductwork shall be mallllfactured in mat fial as pecified in tbis specification Any special coatingpaint fmishes to be provid d by the duct work contractor sball be advisd by th de igner
20 CONNECTIONS TO BUILDING OPENINGS
201 Fanning and finishing building op nings are not the repoJlsibjlity of the duftw( rk contractor and the note that follow are for guidance purpo e only
2011 Openings in brick block or concrete walls shall have inset frames to provide a suitable means of fixing grille louver masking flanges or the tlanged ends of ductwork The illset frames shall be conslnlcted to maintain the structural int grity of the wlll and where applicable cavities shall be suitably lined
2012 Openin s in dry linino partItIons shall have inset frames a 2011
2013 Openjngs in cladding walls and roofs shall have flaoged leevesframes to provide a suitable means of fixing a 2011
2014 Horizontal and vertical opening xposed to oLltside atmo phere hall
be provided with a suitable weathering fini h at the external face especially where profiled cladding is used
2015 Timber framed op nings are not permitted In fj re compart ment barriers
202 Ductwork connections to building openings hall have a flange of suitable profile to permit practical fixing to the openillg frame In selecting the profile consideration shall be given to Tabl~s 2 and 10 in this specitication relating to duct ize and rating Gasket strip or sealant shall be ltlpplied between the tJaoge and building op ning frame
21 DISCHARGEEXHAUST TERMINAL
21 Tbese shall be vertical open ended and designed to meet and comply with current r gularions on contaminated flue The designer hall ensure that the de ign and perf rmance i suitable for its intended purpose Examples of some typical terminal designs are SbOiD in Figbull 102 10 bull 104 amp 105
27
DW154 SpedjimioTl for Plastics Ductwork
22 THERMAL INSULATION
221 The provision and application of thermal insulation to ductwork is not the responsibility of the ductwork contractor
222 Where ductwork is required to be preshyinsulated the specification should be agreed with tbe designer
223 Where the temperature of the air within the duct promotes condensation on the exterior surface of the duct and cause moisture penetration througb the thermal insulation vapour scaling may be required and in this case the most important requirement is to limit penetration of the seal
The extent of any vapour sealing of ductwork thermal insulation and the support method to be u ed must be clearly pecitled in advance by the designer
224 For detailed information on the thermal insulation of ductwork reference should be made to BS 5422 1990 which covers the specification for thermal insulation materials on pipes ductwork and equipment (in the temperature range -40degC to +700degC) and BS 5970 1992 which is a Code of Practic for Thermal Insulation of Pipework and Equipment (in the temperature range -lOOdegC to +870degC)
23 FIRE RETARDANT FINISHES ON PLAST C DUCTWORK
231 The designer should note tbat ductwork constructed to DW154 has no teted fire rating or information see Appendix C
24 REINFORCEMENT OF DUCTS WITH GRP LAMINATE
241 General Where ductwork is required in larg T izes than are covered by Tables 2 4 6 amp 7 or with the increased strength sometimes necessary for industrial use external reinforcement is normally pwvided by applicatioD of glass fibreresin laminate
GRP systems will bond satisfactorily with standard UPVC sheet but for pp it is
nece sary to use a specially prepared sheet with a glass fabric backing incorporated dOling manufactllfe
The detailed techniques of fabrication using GRP are outside the scope of this speci lcation but the following notes are offered for guidance of ductwork fabricators
242 Materials
2421 Quality The laminate is made up of polyester resin complying with BS 3532 and glass fibre complying with BS 3496 or BS 3749 The nominal ratio of resin to glass fibre should be 7030 by weight
2422 Minimum properties The laminate shall comply with the followiog mini mum pbysical properties
Tensile strength - 70 MNm Tensile modulus - 7 Gl m Flexural strength - 140 M Im Bond strength (hetween laminate and substrate Not less than 7MNm Bmcol hardnes Not le s than manufacturers specification
The GRP reinforcement educe the expansion of the parent material but the resultant stre ses arc well within rhe strength of the bond However the Iinear thermal expansion curve shown in Figs 34 amp 35 will serve as a guide
Surface resistivity electrkal propcltles and acoustical propertie are similar to the relevanl unreinforced materials The fire retarding properties of GRP may be improved by the use of specialisl laminating resin
2423 Forms available GRP Laminate should be built up from the separate materials ie resin aod glass fibre in the form of chopped
I strand mat or spray ravings
28
DW154 Spcification for Plastics Ductwork
2424 Workshop conditions Polyester resuls are sensItIve to lmperature and the workshop hould b maintained at a temperature of herween 20deg and 25degC HiOh relative humidities and damp onditions should be avoided A good rate of air change must be pro icled pJeferably by m chanical ventilation
2425 Storage of materials Resin and urin o agents shouJd be stored in dark cool condirions away from the working area and in confonnit with statutor requireshyments for tJle middottorage of flarmnable liquid Because of Ule Limited torage lif of the unmixed resin and curing a eot mal lials ~hould be ch eked before use to enLlfe that they are within the manufacturer pe ified sh If life (usually ix month from the dm of manufacrure)
Glass fi re should be stored separately und r clean dry conditions
243 Surface preparafon
2431 UPVC To achieve the specified bond strengtll the urface to which the GRP is applied mut first be thoroughly cleaned and then etched either by mechanical means or by the use of a suitable solvent
2432 pp with glass fabric backing To achieve the specified bond middottrength the fabric backing must be thoroughly impregnated Witll resin
244 Mixing the materials for use The re in 1 a three part mix compri lng base I sin hardener and accelerator The manufactur rs pecj[ied proportions are critical and th llUxmg sequenc pecified must be meticulously foUowed
The resin has a very limited life after mixing and before u e It is dependent on the characteri tics and bulk of th resin the alllount of hardener the degree and method of acceleration and the workshop onditions
245 Methods of application
2451 General The mixed resin may be applied by hand or b pray c1epoition The operation must b completed within the gel time of th y tern and tbe laminat fully cOI1olidated to achi v the phy ieal properties pecified
2452 Hand lay-up The duct surface i coated by hand with resin Llsing a brush and a mar of gla fibp orked in until full consolidation achieved Th proc is repeated untiJ th requird thicknes i obtained
2453 Spray depo Won The duct surface is coated WiUl re in by spray gun with the chopped glass roving added through a separate nozzle The full thickne i obtain d in layer with con olidation of each layer by hand roller
246 Construction
2461 General M ini mum COllst ructional requireshyments are pe itied ill Tabl 10 for rectangular and Table 1J for circular dUClS
2462 Joints and stiffeners Fig 29 30 31 32 amp 33 hoI TOSS
joint and tiffener for reinforced UPVC and PBPP duct
247 Worki g practices The fabrication of ductwork pecifiecl ill thi document i not affected by the addition of GRP
29
DW154 SfJcdJicatiOt for Plastics Ductwork
Table 10 Minimum constructional requirements shy
Longer Side Minimum Sheet Thicknes and
GRP Reinforcement
UPVC FBIPP 1 2 3
mm mm mm Up to 1000 3 plus 3 plus
06 kgm2 06 kgOIl GRP GRP
1001 to 2250 45 plus 3 plus 06 kgm 12 kgm
GRP GRP
2251 to 3000 45 plus 6 plus 12 kgm 12 kgm
GRP GRP
Cross Joints
UPVCFBPP 4
mm socket amp spigot
as Fig 30 or flanged as Fig 29
75 x 9 flange welded on both sides as Fig 29
75 x 9 tlange welded on both sides as Fig 29
rectangular GRP reinforced ducts
SlifTeners Maximum Spacing Between
JointsSljffeners UPVCIFBIPP UPVCFBPP
5 6 mm mm
75 x 9 flat 800 as Fig 31 or
50 x 50 x 5 plastic or MS inverted angle as Fig 32
or tormer as Fig 33
75 x 9 flat 600 as Fig 31 or
50 x 50 x 5 plastic or MS inverted angle as Fig 32
or former as Fig 33
75 x 9 flat 600+shyas Fig 31 or 50 x 50 x 5 plastic
or MS inverted angle as Fig 32
or former as Fig 33
Note 1 On rectangular duct up to 400 mm longer side no stiffeners are required 2 Applies to Tables 10 amp I I For COlJstructional operating temperature limits refer to Part 2 clause 5A 3 Tables 10 amp II apply to all pres ure classes up lo ]500 Pa
Table 11
Diameter
1 III
lJp to 1000
1001 to 1750
1751 to 2500
Minimum Sheet Thickness and
GRP Reinforcement
UPVC FBPP 2 3
mm mm 3 plus 3 plus
06 kgm 06 kgm GRP GRP
45 plus 3 plus 06 kgm2 18 kgm
GRP GRP
6 plus 6 plus 12 kglm2 18 kgm1
GRP GRP
Cross Joints
UPVCFBPP 4 III
socket amp spigot as Fig 30 or flaoged as Fig 29
75 x 9 flange welded on both sides as Fig 29
75 x 9 flange welded 00
both sides as Fi 29
inforced ducts
Maximum Spacing Between
JointsStiffeners UPVCIFBPP
6 mm 2400
800
600
Stiffencrs
UPVCFBPP 5
mm 50 x 9 flat as Fig 31
75 x 9 flat as Fig 31 or former as Fig 33 75 x 9 tlat as Fig 31 or t()rmer as Fi 33
ote On extruded tube tip to 600mm diameter no stiffenergt are required
30
DW154 Specificatioll for Plastics Ductwork
G - Cross joints and tiffeners
Fig 29 Flange Joint Fig32 Stiffener shy inverted angle
M artiPfCuQkbdd erttpObri) Wl111 RP tlddtlt
_- GRPloliu] lh~
Fig 30 Socket and spigot joint Fig33 Stiffener shy use of former
Fig 31 Stiffener Flat
I Pv FlPP ~ ~lmJaDUA1) d
OMrlQ rrnall 1( tQlS
25 STANDARD COMPONENT DRAWINGS AND ABBREVIATIONS
251 The illustrations in this section not only highlight where applicable geometric limjtations for the de ign and manufacture or ductwork components but also recommend
standard drawing representation terminology and abbreviations for both duetwork components and some of the more commonly used ancillaryplant items
252 Designers and surveyors should note that bills of quantities should provide a full description
3)
---
v
DW154 Spcc(fim(ml for Plastics Ductwork
Fig 34 Linear Thermal Expansion
u c 0 N ro 0)
b 0)
S
sect0
5 oS cl) 0)
~
on ~ ltl
c U
-30 -20 -10 0 10 20 30 40 50 60 70 80 90 TEMPRATURE C
~ V
-
~~c_ ~
~V
V ~
-7 ~
-- ~V ----
v
-6
+14
+12
+10
+8
+6
+4
+2
0
-2
--4
ig 35 Typical Design Stress tor UPVC and P
7
6
r shy 5E
-c E----0 4t) VJ 0)
ci5 0Jl 3
~
0)
Cl
2
1
o
UPVC
1
000
1
1
pp
- r-- shy r----- shy - t--shy I
__0
-30 -20 -10 0 10 20 30 40 50 60 70 80 90 TEMPERATURE C C
Note Figso 14 amp 35 shaded area refers to GRP reinforced duct
32
DW154 Speciicfltirm for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - REC ~NGULAR
Splilt~r Posilion W-mm pliucr
A B c 40]--QOO 1 W - -
601-1000 1 W4 Wf2 -
1001-1800 3 WI W3 W2
FIG DRAWING DETAfiS
tU]36 ATI Straight Duct with socket and spigol joint
rn [037 Straight Duct with flanged joints
[I []38 Straight Duct with flanged joints
rkJ Short Radius Bend
39 Applies to any augl and for duct up to 400 n11n wide
Minimum (I1m31 radills = 100 mm
Medium Radius Bend (a illustrated)
[kJ Applies to any angle
40 Long Radiu Bend Similar but radius = W
Throlll radius = W2 Applies to any angle
- Short Radius Bend with plitlers
I -shy -shy u co - t lt Li--_ 41 t 0 ~ I I I
~ I
L 1W
Minimum waal radius = 100 mm Splitters not required in bend angle less than 45deg
42 QJ1 Square Bend with turning vanes ij
3
DW154 SP(L~ficatioll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - RECTANGULAR
FIG DRAWl G DETADS
43
~
I v
L L Radius Tee with internal deflectors
44
~ Radiussed Twin Bend
45
Imiddot
er Swept Branch
46 U-
Sqoare Tee with Turning Vanes
47
~ f
Breeches Piece
48 0 y l Piece
34
DW154 Specificatioll for Plastics Ductwork
STANDARD COMPONENT RAWINGS - ECTANGULAR
55
54
51
50
53
52
49
FIG
~MX
RAWlNG
DmiddotMAX
EfjMAX
Minimum throat rndius = 100 mm
Rectangular shy Round Transformatioll
Eccentric Taper 225deg max in either plane Spliller are required for angles greater than 225deg and hould bi eet the angle between any side and duct centreline
DETATLS
Angled Offset
OUset Taper Splitters are required for angle greater than 22 0
and shoold bi eet the angl between any side and dUCI centrelinc
Mitred Offset
Concentrk Taper 2250 max in ither plane SpUtters are required for angle greater than 225deg and should bisect the angle between any side and duel c ntreline
Radiussed Offset
35
DW154 Splcilcuthm for Plastics Ductwork
STANDARD COMPONENT DRAWINGS ~ RECTANGU AR
Branch ducl DimCllsions widlh (W) (A)
urnl mm up lO 200 75
300 100 400 125 600 150
Ocr 600 200
FIG DRAWlNG DETAILS
56 poundplusmni~~ Rectan~lar - Flat Oval Transformation
57 [ Square Branch
58 er Angled Branch
Branch dUCI Dimensions wfdth (W) (A)
[- mm mm59 3shy Shoe Branch Up (0 200 75
--shy AIshy + 300 100
400 125
450 MAX 600 150
Over 600 200
Branch duct DimensIOn
rP X width (W) A)
60 - 1--shy _
~ mm mm
Bell Mouth Branch pto 200 75 300 100 t 400 125
600 150 Over 600 200
0=0 61 -
~ Bell Mouth
- shy T 4-5deg M x
--I 1-shy
TJ
62 X I ] I
Tele-scopic Joint I Illustrated with flangeL
X63
SBD Single Bladed Damper
36
---
DW154 Spedicatioll for Plastics Ductwork
STANDARD OMPONENT DRAWINGS - RECTANGULAR
DRAWING DETAILSFIG
64 on-Return DamperNRD shyshy
shyXbull
Multi-Leaf Damper Can be piggoted or flanged oppo cd or parallel blade
Alternative controls areshy
q p [gtshy
J HD65 Hand
~MD otori ed
PO Pneumalic
L-lt
l 13G 66 Blast Gate DamperX X
FireSmoke DampersSleeves
211r Ratinggtshy----
L_-
---
----
r----
Ir-- shy
IL- _-l
2hr
With i tallation frame
67 41 r Rating
4hr
Smoke damper SD
Intumc cent Sleeve L-d
37
DW154 Specijicutiolt for Plastics Ductwork
FIG
68
69
70
71
STANDARD COMPONET DRAWINGS shy REC ANGULAR
DRAVING DETAILS
gtshy Access Openings
AP 6 Access Panel - Rerno able
w [ ~ Access Door - Hinged
I ~le Inspection Cover
le -I reg -lt
~X X Flexible Connection
~ Drop Cheeked Radiussed Twin Bend
U Drop Cheek Bend
I
72 Air Flow SymbolX
38
DW154 Specifim[ioll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - ECTANGULAR
FIG DRAWING DETAILS
73
74
75
76
77
Q
Q
rp---t
~
V- I Ir---I
JL --11
THE ABOVE DETAILS TYPICAL PLENUM
Air Terminal Plenums
Plenum with side connection
Plenum with top connection
Cover plate with connection
Special plenum with connection
elescopic conn ction in direction of air flow
39
DW154 SpecijicotiOll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG
78
79
80
81
DRAWING
-23~---pound3-(MALE) (FEMAJE)
-t=j--_j(--d-shy
--L
~ THROAT RADI S= D AS T NDARD
e ~
THROAT Rjf)lU = D A MU)
DETAILS
Straight Duct With male and female connectors
Straight Duct With flange joint and slip joint
Bend MouldedIFormed Applies to any angle ego 30deg45deg60deg90deg Medium radius bend as illustrated Long radius similar but throat radius 0
Segmented Bend 90deg four section minjmum as illustrated
Other Angles 60deg = 3 sections 45deg = 3 sections 30deg = 2 sections
I
i
40 shy
DW154 Speciicafinll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG DRAWING DETAlLS
82 Segmented Twin Bend Radius = D2 max
May also be fabricated from tube
83 Equal Tee MouldedIFormed
84 -~ 1in Bend MouldedIFormed
85 Taper Concentric 1 0 as iUu trated Eccentric 30deg iJJcLuded angle
86 Short Taper
41
DW154 SpcUicatol1 for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG DRAWING DETAILS
87 30 max Offset
Angle Branch
Bran h dUCI Dimcnsions dia (D) lA)
Shoe Branch mm mm 88 Cl
Off rectanguJur Up 10 200 75 lOO 10 400 125
- 00 150 Over 600 200
Bl1IllCh duct DimenlOns din (D) (A
~-$a-Conical Branch mm mm
89 Also acceptable with Up 10 200 r
full conical surface 300 10
400 125
END VrE -shy 600 150 Over 600 200
90
m 75
100 12 150 200
mm Up to 200
_ 300 400
600 Over 600
iUtred Branch
Shoe Branch
J-L----U ~ Bell oulh Branch
ENDV1EW
93
92
91
42
DW154 Specificatiol for Plastics Ductwork
STANDARD OMPONENT DRAWINGS - CIRCULAR
FIG
94
DRAW G
I
~ 30deg 090deg
Breeches Piece
DETAILS
95 amp-----~ Blank End
~-----p Multi-Leaf Damper Can be piggolcd or fianged opposed or parallel blade
Alternative controls areshyri=-+- L-T~
I
---
LT~
I r- -
-+1
J HO Hand96
bMD Molori cd
PD Pneumatic
tl-shy bull
Single Bladed Damper 97 ~ saD
on-Return Damper Vertical application only 98 m~D
43
DW154 Sf1tcificatioll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG
99
100
101
102
DRAWING
$ I-
2hr
1 4hr
SD
~v I I
CO TINENTAL COWL
DETAILS
Iris Damper
Fi reS moke Dam persSleeves
2hr Ratillg
With installation frame
4br Rating
Smoke damper
Intumescent Sleeve
Access Openings
Access panel - removable
Access door shy hinged
fnspection cover
Discharge Continental Cowl
44
DW154 Sp(Cii(ltJll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
DRAWINGltIC DETAns
-
I
I
~
I I I High Velocity Discharge Terminal 103 I
I
I I
J I I 1 ~--
Offset Stack Discbarge Terminal 104 1
~ I e --(-
I
N
I
I
I~
I I Vertical Oischarge with Weather Cowl 105 I
--1--1 I
I
GAPI I
RTl AL DISC) lARGE WITH W ATIIER COWL
45
DW154 SpecUicatoll for Plastics Ductwork
STANDARD COMPONE T DRAWINGS - PLA TEQUIPMENTIMISCELLANEOU
FIG DRAWING DETAILS
106 ~~~ Rectangular Attenuator
107 ~- Circular Attenuator
108
~ Beod Attenuator
109 J ~(f) Heating Coil
110 J ftte Cooling Coil
III Jc[ Electric Heating Coil
112 X F
Humidifier
113 [H XX Axial Fan
114 ~fB1famp Noo-standard Ductwork Cross hntchillg (of any separate type) indicates by reference to a key any non DVil54 ductwork system
115 2llIIIIJIIIIIll Flexible Ductwork
46
DW154 SJeCUicll(iol1 for Plastics Ductwork
TABLE 12 - STANDARD ABBREVIAT ONS
ABBREVIATION FLL
AD Acces Door
AFF Axial Flow Fan
AHU Air Handling nit
All Aluminium
AP Acess Panel
AT Attenuator
AV Air enninal Unit
BE 81ank nd
BQ Blast ate Damper
CC Cooling Coil
CF Centrifugal Fan
CTA Cross alk Attenuator
CVU Constant Volume Unit
DP Drain Point
EEC Electric Heating Coil
El Expansion Joint
FAl Fresh Air Inlet
FA From Above
FB From Belo
fBPP Fabric Backed Polypropyl-ne Sheet
Flexle Flexible Connection
lexfD Flexible Du t
C False Ceiling CO an oil Unit
fD Fire Damper
FFL Finished Floor Level
FJ Flanged Joint
FOAM Rigid Polyurethane Self xtinguishing Foam
FOB Flat on Bottom
FOT Flat on Top
GAM Galvanised after ManufacttrJc
GRP Glass Reinforced Plastic
GSS Galvanised Sheet Steel
HC Heating oil
HD and controlled Damper
HH Hand Hole
HL High Level
HVD High Velocity Discharge
IC Inspection Cover
ID lri Damper
IFS Intumescent Fircleevc
47
DW154 Specification for Plastics Ductwork
TABLE 12 - STANDAR ABBREVIATION CONTINUED
ABBREVIATION
IU
L
tv1D
MS
NRD NTS
OBO
OE
PHD
PD
PP
PP
PRD
PVC
RFC
RSC
R
SBO
SO
S1 TST
SSL
TA
TB
TO TJ
TP
TV
TV
OS
UPVC
S
V
VAV
50 RSA
FULL
Induction Unit
Low Level
Motor controlled Damper
Mjld Steel
on Return Damper
at to cale
Opposed Blade Damper
Open End
Parallel Blade Damper
Pneumatic controlled Damper
Polypropylene
Self xtinguishing Polypropylene
Pressure Relief Damper
Polyvinyl Chloride
Rolled Form Chamlel
Rolled Steel Channel
R fUnit
Singl Blade Damper
Smoke Damper
Slip Joint
Stainl t el
tructural Slab Level
To Ab vc
To Blow
Top Down (In Direction of Flow)
Telescopic Joint
Test Point
TU111iog Vane
Top Up (In Direction of Flo )
Voles Otherwise Stated
Unpl3sticisecl Polyvinyl Chloride
Underside
Ultra Violet Light
Variable Air Volume
Rolled Steel Angle (Vith Size)
48
DW154 SJeriiflllioll for Plastics Ductwork
A2 DUCT PRESSUREAPPE DXA Ductwork con truct d to DWIl54 will bebullbullbullbullbullbullbullbullbullbullbullbullbullbull
Air Leakage From Ductwork To be read in conjunction with DW143 A practical guide to Ductwork Leakage Testing
CAUTION As highlighted ill both this docul1lenr and DW14 I lot ellough emphasis can be placed 01 the fact that except for high pressure class C the much more stringent ductwork constructional standard brolght about b the general acceptance of DW154 have irtlally negated the requirement for leakage-testing It is essential lO realise lhat except where it is mandatory this doclllllelll is nOl an endors ~lIlent of the rourine testing of ducts bllt purely a guide to outline the procedures for cononnity with the air leakage limits ill Table l Where the specified methods of assembly and
A3sealing of dlcls are u ed a vi ual inspection wil ordinarily sl~fll e for ver(iatioll of a well engineered and a ceptahfy airtight COl1strucrioll WHERE NOT MANDATORY DUCT LEAKAGE TESTING IS GENERALLY AN UNJUSTIFIED AND SUBSTANTIAL EXPENSE
A1 INTRODUCTION L akage from ducted air distribution systems is an Lmportant consideration in the design and operation of ventilatjon and air conditioning middotystems A ductviork t)ystem tbat ba limited air leakag within defiucd limits wiH cnsUft
that tile design characteristics of the sytem can be maintained It wilJ also ensure that energy and operatLonal cosb are maintained at optimum levels DucLwork constlucted and Ulstalled in accordance with DW154 should minimise a level of air leakage that it) appropriate to tll operating static air pre sur in tile system
A4However it is recouuised that tbe environment in wtJich middotystems are installed is not always conducive to achieving a predictable level of quality in term of system ajr leakage and it is therefore accepted that designer may sometimes require tlle ystem to be tested in part or in total It should be ecogni ed that the testing of duct systems add a ignificant cost to the installation and incur some extra tjm within the programme (Se 47 and 64 re mandatory te-sting)
manufactured to a structural standard that is compatible with the system operating pressure There are three classes of duct con truction to eorre pond with the three pre ure clas meations Class A Lo pressure ducts suita le for a maximum positive operating pressure of 500 Pascal and a maximum negative pressure of -500 Pascals Class B IVledium pressure ductmiddot suitable for a rnaxilnuJJl positive operafjn o pressure of 1000 Pascals and a maxllnum negative pre sure of -750 Pa cal Class C High pre sure ducts suitable for a maximum po ilive operating pressur of 2000 Pa cals and a maximum negativ pres ur of -750 Paltcals
LEAKAGE FROM DUCTWORK Leakao-e front pia tic air ducts occur at the joint~ and is therefore proportional to the total surface area orthe du twork in th system Tb level of leakage i imilarly related to tIle air pres ure in th du t system and whilst there LS n precis formula for calculating the level of air los it i generally accepted that leakage will increase in proportjon to pressure to rbe pOvver of 065 The effect of air leakage from high pressure velocit ductwork is critical tn terms of system perfomlan dege energy consumption and the risk of high frequency noise as ociated with leakage These problems are le critical with medium pressure 10 ity systems but should be con idered Low pres mevelocity ducts present the lowe~t
ri k in tenn of tbe effect of leakage on the operation of the s stern
SYSTEM LEAKAGE LOSS As there i no di ct relatLonship between th volume of air conv yed and the surface area f the ductwork sy tern required to match the building configuratmn it is difficult to express air leakage a a percentage of total air volume Similarly the operating pressure will vary throughollt lh 3 system and a leakage is related to pre me the calculations ar comple However it is generally ac epted tbat in typical good quaJjty systems the leakage from
49
DW154 Specificatioll for Plastics Ductwork
each class of duct llnd r operating condition will be io the region of CIa S A low pressure 6 Clas B medium pres un 3 Clas C high pressure 2
A5 SPECIFYING AIR LEAKAGE TESTING Re peeting both the co -t and programme implications a sociated with te ling du 1 for leakage the designer may for example indicate that a particular system is te ted as follow
a) High pressure ducts - all tested b) Medium pr ssure duets - 10 of the
ductwork shall be s eet d at random and tested
c) Low pre sure - unte ed In any case where a random te t i elected for medium pre sure ductmiddot the followin c1au~e is suggested for inclusion by the de ign r
The designer hall elect at random a maxirnwlI of 10 of the dUCl system to bt tested for air leakage The duct hall be tested af the pressure recommended in Table J3 for the assifi atiol for the ectiol1 of the ductwork that is to be tested The tests shall be carried Ollt as the work proceeds and prior to the application of thermal insulation In the event of test failure of the randomlY selected section the designer shall have The right to select two La1her e tiolls at random for resting Where succes ive failures are identified there shall be a Tight to require rhl COl11raCWr 10 apply remedial attention to the complete ductwork system Th contractor shall provide documented eviden e of the calculalions used to arrive (1
the allowable 10 I for the section to be tested and the client or his agent shall willess and sign the results of the test
able 13 Air leakage rates
Maximum leakage of duct work Static
prcssUft Low-pressure edium-prc-sure I Iigh-prebull me diJfercntial Class A Class B Class C
1 2 J 4 Pa Litres per second per quare metre of surface area 100 054 018 ZOO 084 028 300 110 037 400 132 044 500 153 051 600 058 019 700 064 021 800 069 023 900 075 025
1000 080 027 1100 1200 1300 1400 1500
029 030 032 033 035
1600 1700 1800 1900 2000
036 038 039 040 042
Note Recommend d mean test presures are highlighted iD bold type with the actual selection being left to tll test operator
50
DW154 Sfeeiieaioll for Plastics Ductwork
A9
A10
and air leakage classification for the y em under test
DESIGNERS CALCULATIONS The designer can middotaJculate with reasonable accuracy the predicted total loss from a ystem by
a) Calculating the operatin presure in each ection of the sy tern
b) Calculating the surface area of the ductwork in each correspondin pre lire s ction
c) Calulating the allowabl~ los at the operating pressure for each ection of the system (see table 13 for allowable leakage figures)
VARIABLE PRESSUR S IN SYSTEMS De igner can achieve significant co t saving by matchina operating pressures throughout the system to constmctional standard and appropriate air leakage testing eO the practice of specifying construction tandards for whole duct sy tems based on fan discharge pre sure may incur unnece sary costs on a project For example ome large sy terns ould well be classiC ed for I akage limits as follows
Plant room risers CJas C Main floor distriblltJou CIa B Low pre sure outlets Cla A
A6 SPECIAL CASES There may be ~itLlations on a project where circumstance dictate thal pecial consideration be given to containing air loss s eg a long mn of duclwork may incur a di -proportjonate level of air 10 s In ca es such as thi example the designer can specify an improved tandard of airtighmess ie 80 of alJo~able 10 s for la B Ju ts The designer sbould not specif a CIa C t sI at CIa s C pressure for a CIa s B ducl
A7 SUGG S ED RANGE OF TES ING
A8 TESTING OF PLANT ITEMS Items of inline pJant (eg Fig 106 to 115) will not normaUy be included in an air I akage test The dllctwork contractor may indud such itelllS in tbe te t jf rh quipm ot has a certificate of COnfOlnlity for Ihe pres ure clas
bull High pressure duct bull Medium pre sure ducts bull Low pre sur ducts bull Exposed extract syst ID bull Ceiling void extract
systems bull Secondary ducts from
VAV or fan coil units bull Flexjble duct bull Final connections and
branches to grille and diffusers
100 test See A5 Untested UDt sted
Untested
Untested Untested
Untested
SI
i
DW154 SJecijicafion for Plastics Ductwork
ig 116 Permitted leakage at various pressures
Leakage in litres per second per square metre duct surface area
Vgt
o ltgt 0 ltgt N
ltgt Cgt
0 0 cc
0 0
~
g =
g ~
c 0
J
ltgt 0 I
~ ] tn
ltgt ltgt
In ol
~ 0 ~ 8 ~
~
c ltgt ltgt
~ CJ
~ ~ ~ ~ 8
0shyij
~ ~ ~ t
ltgt ltgt 00
l
~
~ Q
c C
~ rshy
e ltgt
I 1
I Cgt ltgtv
c Co ~
~~ ~ 10
I
0 Cgt
fJshyq 410 ) 1 ltgt
ltgt N
~ shy ltgt ltgt
~ I 1
c
52
DW154 Specificatio for Plastics Ductwork
Example of a completed test sheet Test No
General
Name of job N~ jC43Pt(r2lef Building Repound ~(~~0
Part 1 - Physical details
a Section of duct work to be tested ~(diffPIfff~el1f3rd Floor
b Drawing Number g91~~ c ssure aSSJ L atlOn V~Jl~IRfYgtg~~lPre Cl T Class C
d Test static pressure -(9 raErq~ ~~~~-~~J~~~ ~~ ~~~~ll
Leakaoe factor 9~-tre3$ecMz I OM REFTOTABLE 13)e b bullbullbullbullbullbullbull
f Surface area of duct under test Q~tJJItetre$ CPROMCALCU TIO BELOW)bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull ampampamp bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull
g ]Vlaxi mum permitted leakage -~ (~i~~0 ~~r~~ ~~~l-~-11~ ~~~Q
Part 2 - Test particulars
a Duct static pressure reading 9QFt~q~ ~ middot~~~1 ~~
b Manufacturer and type of liow measuring d vice (-~~~cJ~Y-9Q7EYg c Range of measurement of now measuring device QtP)OQ~(e~~~0I~~~~1~I~ ~~~~~~W~
d Reading of flm measurin o device pmiddot IFROM RIO)ftscag ~
I (DERlVED [ROM CHART SUPPUED WITH RIG US 0 ud)1e Interpreted air flow leakage rate ~(~~~f~~~ (~l~~~~~~~~~~~~~~~~~I
f Duration ~~~~~norn~allY l~ lnil1Ut~~d~~~ it1~ W~ Date of test ~(lITled ut by Wltll s ed by ~ ~
(~lJ MIJLrr) (Si~rrfltJUYJ
Printed Name 1~g0f~ Printed Name ~~Y~9~ and Company 7jl~~~~~( UJd CompanY AB COII$Itallt8
Width and depth or diameter
Periphery ength Area
millimetreS millimetres metre qL1are metre
800 x 750 3100 1755 5440
600 x 650 2500 557 1193
300 x 300 1200 120 144
305 din 958 700 670
250 dia 785 450 353
TOTAL 8000
53
DW154 Specijilarion for Plastics Ductwork
pA XB
Guida ce No es For he ransport Handling and
Storage of uctwork
avoid damage to adjacent duct panels In somc ca es particularly on con acts calling f r repetitive sizes the use of timber jigs and spacers may be justified Where reduced bulk and greater protection are major factor such as consignments for export transporting ductwork in L shape sections may justify the increa ed ite as embly co ts
It is recommended that before a contract is finalised that consideration is given to the subject of site acces material handling and storage as tbcy havgt a strong influence on the cost efficiency of the overall activity of ductwOlk installation
B3 Handling To minilnise th risk of damage duct sections should be clearly identified and deliveries to site should be closely linked to the installation programme so as to avoid accumulation of
B1 Storage and Handling of Ra Material Material should be stored in suitably designed racking out of direct unJight Where possible the e racks should be metal to earth Edges of cut she t may be harp and protective gloves are advised Wearing teel toe-capped boots is recommended Most pIa tic sheet is manufactured with smootb mfaces andor is suppLied with protective coating Care must be taken to prevent accidental lippag of stacked materials Beiuoshy good electrical insulators the movement of stock unless earthed will allow the build up of stati All stock shapes are chemically stable at normal temperature Whil t some raw materials used in their manufacture may themselves pre ent a toxic hazard once incorporated into the lOck bape they no long r constitute such a hazard and no dermatitic bazard are known nor are any
unfiJied ductwork and minimise double handling It is important to recognise that ductwork panels joint and corners arc susceptible to damage and care must be taken wheu band ling such material through a site During handling individual item of duct work may be liable to light cross sectional deformation until thev become an integral pan of a completed ductwork system Whilst this may temporarily detract from its intended appearance thi deformation will not have any detrimental effect on the functionality of the finally a semblecl system Installation of duct work and asociated plant items ill illevitably involve manual handUng The responsibi Iiry of employers and employees to a ses the risk of personal injury during mallual handling operations is et out in the HS E publication L23 Guidance on Manual Handling Regulations 1992
environmental problems expected 84 Site storage
B2 fransport Large capacity vehicles with high-sided open or closed-top bodies are tlle mo t suitable for the transport of dllctwork Careful consideration should be given to the
Adequate floor space IDust be provided within tbe building for the site storage of ductvork Such storage shalt make due allowance for thc stOf(ne of ductwork in stacks such that access ~ egt
between them is of sufficient width to pennil the removal of item without interference to
unloading of transport on sit a not all siJes b n fit from the material handlino- and access facilities that exi [ in a manufacturing workshop such as crane- fork-lifts or loading bay Site handJiog facilities along with
adjoining sta ks Ductvork components should be positioned so a to avoid crushing Ductwork of small panel size may be stored horizontally however care should be exercised to ensure that tack sizes are limited 10 within
ehicular acce s restrictions may itilluence the type and ize of transport to be uWised
engtlls of ductwork should be positioned 0
the tmctural strength of the duct sections to prevent distortion of the lower sections within the stack
as to avoid crushing Lengths Witll projections such as branches and bends i1anges girths damper quadrauL should be loaded so as to
54
DW154 S1tciic(ltioll for Plastics Ductwork
85 Internal cleanliness of new ductwork The site storage of ductwork introduces the important cODsideration of maintaining the internal cleanliness of the ductwork R feren e should be made to HVCA documentshybull DWffM2 Guide to Good Practice - internal
Cleanliness of New Ductwork Installations If the above conditioDs can not be satisfied consideration should be given by tJle designer to amending the specification to include for Po t Installation Cleaning as covered by tJ1C HVCA documentshybull TRJ17 Guide to Good Practic - Cleanliness
of Ventilation Systems
APPE DIXC
Fi e Retardant inishes C1 Improvement in the fire retardancy of plastic
ducts can be achieved to varying degrees and is wholly dependent llPOll the surface coating laminating resin selected and construction specification adopted In some instances smoke emission is coILSidered equaUy with other speci fication requirernen ts of the materials resistance to ignition and bumjng It is therefore important for design rs to establ ish the clients and officers detailed requirements and not rely on a tbird party interpretation of fire resisting or fire retardant Where possible the specification should refer dir etly to compliance with a British or European Standard identifying the specific sections applicable There are various types of resin and mat rcLnforcements that can achieve a Class 1 surface spread of flame ratin o when tested according to BS476 Part 7 (1987) This test puts materials illto Class I - 4 in descending order of perfoDllance according to the rat and extent of flame spread over their surfac under standard beating conditions Materials should also be tested for flre propagarion to BS476 Part 6 (1989) Tbi tesr measures the amount and rate of heat evolved by the material when subjected to standard heating
conditions Test results are given as an index of Perfonnance (i) whicb is based on three sub indices (iJ (i1) (h) The higher the value of the Index of Performance (i) the greater is the material s contribution to fire growth The higher the value of the sub-index 0) rhe greater the ease of ignition aod flame spread The highest product performance classification as defined in Approved Document B of the Building Regulations is Class O This is acLlieved if a material surface of a composite ploduct i~ either a) composed throughout of materials of
limited combustibility or b) a Class I material which has a tlre
propagation index (i) of not more than 12 and sub-index (i l ) of nor more than 6
01 J Class 0 is not a cla$sif1cation identified in any British Standard test
There are resin system reported to be classified to Class O when tested to BS476 Pcl1S 6 and 7 however designers need to ensure that such sysrems can be applied to their proposed design In propriety resinmat system available the fabrication techniques and COITect application are critical to the integrity of the reinforcing and clas ificatiol1 For example in some systems the u e of a non-fire retardant gelcont on a fire retardant substrate would reduce the classification For further information see HVCA publication DW144 Appendix D
55
DW154 SplCijiClIliol1 for Plastics Ductwork
x Guidance otes For nspectmiddoton Servicing a d
Clean-ng Access Openings
D1 GE ERAL This appendix highlight in ummary fOI111
the acce considerations that hould be made by the design r iD terms of inspection servicing and cleaning Having considered the seop and the design of the dUCI work system relative to the guidelines outlined below the designer should clearly indicate which levels of acces should be incorporated into the manufacture of a new duct work system (See Table 14 and Note I b low it
D2 DESIGN CONSIDERATIONS
D21 In ptction and servicing requireshyments are set out in Section 15 of Lhis specification
D22 Cleaning requirements are set out in the HVCA pubUcation TRl7 Guide to Good Practice Clean Lines of Ventilation Systems and the guide tates The precise location ize and
type of access would be dependent on the type of ductwork cleaning inspection and te ting metbods to b adopted Care protection and standards of cleanliness prior LO cOlllmisionin o
are set out in th AV A publication DWITM2 Guide to Good Practice Internal Cleanliness of New Ductwork Installations and th guide state Wh re specific limits of cleanliness are required ductwork sball be cleaned after installation by a spcialist cleaning contractor It will b in the interests of tht desioner botb financially and practically to cunsider employing a specialist c1eauing contractor at tbe
outset of a contract to internally clean newly installed ductwork prior to bandover This approach would reali e the following benefit shyi) Tb actual numb r of cleaning
access panels could be detennined to suit the method of cleaning to be adopted (This may be 1 s than the maximum requiremen listed under Lev 13 of Table 14)
ii) Clear directions could b given to the ductwork contractor as to tJle size and location of cleaning access panels that are required to be fitted during the mauushyfaclunng pro s
iii) The specialist cleaning operation prior to commi ioning vould enable the cleaning contractor to verify the practical acee requirement for the future cleaning operation associated -vitb a regular maintenance programme
iv) A specialist cleaning operation prior to commissioning would allow the designer to omit from the speeilicatiolJ the DWrrM2 requirem nt for factory sealing protection wipe downs and capping-off
v) Specialist Ieall ill 0 to the measurable standard defin d in TR17 will allow an objective definition of cleanline to be achieved
Car ful consideration must be gIven by the designer to the practl aJ problems associated witb the manufacture and fitting of suitably si Led access panel on small cross section duct and on the circular faces of rouod and flat oval ducts in particular
D23 Special con ideration must be given by the de igner to the practical problems associated with gaining personnel access to heavily congested ceiling areas and multi-la red du twork systems This approach would avoid
56
DW154 Spfciication for Plastics Ductwork
the possibility of access panels being D3 ACCESS 0 IN-LINE EQUIPMENT incorporated into a ductwork system at the This appendix unly covers acc il1spection manufacturing stage that were later found in through the ductwork body adjacent to an item practice to be inaccessible for either ervicing of in-line equipment and not openings in the or cleaning activities equipment itself
able 14 Acce requirements for inspection servicing and cleaning
HVCA PUBLICATIO REFE NeE (uidtgt 10 Gund Prartict
Adjace t OW144 Cleanliness orVcnlillltio S~lcr~ fRjJ7
in-line LeyeJ 1 Level 2 Level 3 ite sequipment pcdionSen lcin~ Section d C1eaniJl( SUn(O)lnspc lion Palle ltk~m_n
2011 (minimum OiL Jubje-ct to duct ~zel (ft~ -Panels
Control Da pcrs One (inspection) 203 One 300 mm x 200 mm Both sid Fire Dampers One (sCTjdJl~) 20211 One 300 0101 x 200 mm One side HeatingCooling Coils One (inspedion) 20213 One 300 mm x 200 mm (lIpstream) Both sides Attenuators (rectangular) None required One 300 mm x 200 mm (downstream) Both sides Attenuators (circular) one retluired One 300 mm x 200 mm (downstream) One side Filter Sections One (inspection) 20212 one required Uoth sides Air Turn Vanes None requjred None required Both sides Changes of Direction None required one required One side In-Duct FansDevices One (inspection) 20213 None required Both sides l
1 In the absence of any indication by the designer only Level ) access will be jncorporated into a new ductwork system
2 Tbe panel izes associated with Lev lis I and 3 acee s ar e middottablished by reference to Section 20 of DW144 and Section 2 ofTRll7 respectively
57
DW154 Speclfifatio for Plastics Ductwork
pA XE
B-bliography Included in this Bibliography are technical pUblications which may be of interest (0 ductwork designers fabricators and erectors and to tho e in the heating ventilatlng air conditioning industries generally nquiric should be made of the relevant organisation at the address quoted Since its publication other addresse contained within 0V154 mav have changed and some pubJicalions may have been superseded
HEATING AND VENTILATING CONTRACTORS ASSOCIATION
4 Palace Court London W2 4JG Telephone 020-7229 2488 Fax 020-7727 9268
Orders fo FlY A Publications Old Matlsion House Eamont Bridge Penrith Cumbria CA 10 2BX (Telephone 01768 864771 Fax 01768 86718) Email hvcapoblicationshvwelfarecouk DWn 44 pe ilicatiun for sheet mctal duclwork (Iow- mediulllshy
and high-pressure) 1998) DWIl4 A practical guide to dUGI ork I akage te ting
(revised 2000) DWII54 Specification for plastic~ duct rk DW171 Guide to good Practice for kitchen venlibtion system DW191 Guide to good pracuce glass fibre ductwoJk DwrrMI Acceptance cheme for new products - Redangolar cro
joint classification Guide to good pra tice - Internal cleanliness of new ductwork installations Guide to good practice for the design for the Installation of lire and smoke uampers
J 1Other puhlications
HampV safely guide 5th edition JS2 Tool box talks JS5 Weldlng Safety booklet JSI9 afety facts bo klet Fact sheets 1-24 2nd edition JS2J COSHH manual volume 1 Advice on compliance with the
regulations 1521A CO I-rH manual volume 2 Asses mcnt h ets JS23 Ri k management manual TR3 BrazinltT and bronze welding of copper pipework cUld sheet
(I 976) TR5 Welding of carbon steel pipework (1980)
TR6 Guide to Good Practice for Site Pre sure Testing of Pipework (19 0) Guide to good practice cleanliness of ventilation Ylem
CHARTERED IN TITUTlO OF BUILDING SERVICES E G EERS Delta House 222 Balham High Road London SW12 9BS rTelephone 020-8675 5211 Fax 020-8675 5449) CIBSE Guide Volume A Design Data Volume B In tallatiol1 and quipment Data Volume C Reference Data
CommlssioniJIg Codes These Codes eover the preliminary checkS eUing to work and regulation of vanous catcgories 0 plan The Codes give a guide to design implications Series A Air Distnbution Systems Series B Boiler Plant
ri s C Automatic Conlrol ystems Cr1es R Refrigerating Sy terns
Sene iN Water Distribution Systems
Technkal Memonllda TM 4 Design Notes for the Middle East TM bull Design otes for Ductwork TM 13 Minimi iog lhc Risk of egiounaires Disease
Research Reports RROI95 Ventilation system hygiene - A review of published
infomlatioo on lhe occurrence and ffects of Olltamination Rl~02J95 Air-to-air heal rec v ry RR0395 rnfluen e of HV C on smoke detectors
ATlONAL ENI [ERING SPECIFICATION LfMITED Southgatc hamber 3739 Southgate Street Winchester S023 9EH (Telephone 01962 842058 Fax 01962 R(8982) BUfLDING S RVICES RESEARCH AND [ ORMATION ASSOCIATIO Old Bracknell Lane West Bracknell Berkshire RG 12 4AH (Telephone Brackl1eU (01344) 426511 Fax 01344 487 -7 )
Application Guides AGln4 De tglJing Vana~le Volume middotylans for KOOnl
iir Movement AG1I91 Commissioning of V Sylcms in Buildings 11 6194 Fire Dampers
B) 94 cntiJalion or KitcneTls
AG389 The Commls ionin of Air Systems In Buildmgs AH2192 Commissioning of Bern - A ~ode of Practice TN2417 I Fire Dampec il) Ventilating Ducl
BEATING VENTILATING A AIR CONDITION G MA UFACTURERS ASSOCIATIO (HEVAC) HEVAC Henley Road Medmenham Marlow Buck SU 2ER (Telephone 01491 578674 ox 01491 575024 Emoimiddot infofetacouk)
Publicatjons Air Diffusion Guide Guide to Air Handling Unit Leakage Testing Guide to Good Practice Air Handling Unit Real Room Acoustic ~ st Procedure Specification for the ertiiicatioll ofAir Filters Method of Test for Water Rejection PerfOnTlatce of Louvrcs Subjected 1(1
Simulated Rainfall Test Procedure for Acoustic Loo cs Specification 10 Floor GrilJes - Types Performan e and Method ofTest Specification for the Determination of the Collection Efficiency of SilJ1d
Trap Louvre Domestic Mechwlical Vclltllalion Systems with Heal Recovery Fan Application Guid
~an and Ouctwork Installation Guide Guide to Fan Noise and Vibration
pecification of Requirements for JallJral Smoke and Heal Exhausl Ventilators
pecification for Powered Smoke and Heat Exhaust Ventilators
Specification of Requirements for Smoke Curtains Design Gujue of Smoke Ventilation for Single Storey Lodustrilll Building~
Including those with Mezzanine Floor and IIi Racked Storage Warehou es - Issue 3
Guidance for the Design of Smoke entilation YSlem for Covered and Undergrollnd Car Parks - lssue 1
Application of SOloke Control Equipment and Syst m Guid to Good Practice - Isue J
58
DW154 Sp(C~tiifitiol for Plastics Ductwork
BRITISH STANDARDS INSTIT TION Sales Department 101 P ntooviLle Road London NI 9ND (felephone 020-78 1 78801)
CP 413 1973 Ducts for building ervices
SS 476 Fire tes on building matenals and lruc(ure
Part 4 19 4 Non-combustibility lest or materials
Part 6 I Fire propagation lest for materials
Part 7 1993 Surface spread of tlarnJ tesls for materia
Part 20 1987 Fir resistance of elements of construction
Part 21 1987 Fire r sistlUlce of loadbeanng elements of construction
Part 22 1987 Fhe istallceofllon-loadbearing elemcllts ofconsttuclion Part 23 1987 Contribution of componcnts to the fire resistance 0 a
structure
Part 24t987 Fire resi lance of wl1lilation ductl
SS 5588 nan 919 0 Fire Precautions III thc desIgn and OOSlnJ lion of buildings
S 729 1971 Hot dip galvanized oatiugs (or irOIl aod stcel articles
BS 1449 Steel plate sheet and Irip
Pan 11991 Carbon steel plate heel and strip Part 2 1983 Stainless steel plate sheer and strip
and
B middotENJOI49-2 996 BSEN 10149- 1991)
BSEN 10131 1992
BSEN22063 Sprayed metal coarings 1994 Protection of iron and steel by aluminium and zinc against
atmospheric cOlosion Irotectiotl of iron and ste I against corro ion and oxishydation at elevared temperatures
BS 353 1981 Glossary of lerms relnting to thermal insulation
BS ISO 1479 Self-tapplngscrewsandmetallicdri c crew
B -lSO 7049
1994
B 4800 1989 Painl colour for building purposes B 4848 l0 rolled structural steel sections
Part4 1972 Equal and unequal angles BS 5422 1990 Specification for the use of therm illuating matcriulS
SS 5720 1979 ode of practice for mechanical veutilating and air C 11shy
dirionin bull in building
l3S PR 12814-1 Bend resting for plasric welds
SS PR 12814-2 Tensile testing for plastic welds
SS PR 13067 Appro altesting for plastic welds
BS PR EN I 100-] Vi ual in pection ofplaslic welds
SHEET METAL AND AIR CONDITIONING CONTR-CTORS NATIONAL ASSOCIATION INC (SMACNA) Headquarters 420 I Lafayeue Center Drive Chanlilly Virginia 2051-1209
Mailing Address pa Box 221230 Cbantilly Virginilt120 153-1230
Telephone (703) 803-2980 Fax (703) 803-3732
Accepted IJJdustry Pl3Gtice for Industrial Duct Constnlelion 197 ) i-rchitecmral Sheet kwl Manual ([993)
Comractors Guide lor Modification 10 ooslruerion Colllraets 1993 Ducted Eleclric Heat Guide for ir Handling Ssrerns (1994)
En~rgy ollservatioD Guidelines (1984) Energy Recovery Equipment yslClllS (199l
Fibrou GIns Duct onS1ntClion Standards (1992)
Fire Smoke amp Radiation Damper In tall Guide for HVA Syst ms (1992) Guide t leel Stack 1(95)
HVA Air Duct Leakage Test Manual (19 ) HVA COlllmissioning lvlanual (1994)
H A Duct Construction Standards-Metal amp Flexible (1995) Addendum 01 (Nov 1997)
HVA Duct Systems Inspection Guide (1989)
HVA ySlems-Application (1986) nVAC ByternS-DLlct D ign (1990)
HVi Systems-Testing Adjusting amp Balancing (1993)
indoor Air Quality Manual (1993) tcheu quipment Fabrication Guidelmes (1990)
Managers Guide for elding (1993)
Rectangular Industrial Duct Cons1TUction Standards (19 0) Round Industrial Duct oustmction Standards (1977)
Sei mic Restraint Manual (1991) (wl Appendix E 1993) SMACNA Ma le Index ()fTechnical Publications (1995) Tbennoplnstic Duct CPY ) Construction Manual 1994)
DEPARTME OF THE ENVIRO MENT (Publications Centre) H Stationery Oflice 5 Nine Elms Lane London SWS 5DR
MampEJ 011972 Electrical in tallat1011 in buildings ( ew Editiou)
IampE 0319 Healing hot and cold wat r steam and gas losla1lations for buildings
M amp - No4 1970 Central heating and hot and cold ~ ateT in tallations for
dwelling
M amp ENo100 1971 Mechanical ventilation for building~
ASSOCIATION FOR SPECIALIST FIRE PROTECTlO As ociation House 235 Ash Road AJdershot Hampshire GUl2 4DD
Telephone OJ25221322 Fax 0 J252 333901
lublicalioos Fire Ratcd and moke Outlet Ducrwork An Industry Guide t Design and InSlalla lioll
HEALTH AND SAFETY EXEC TIVE Rose Court 2 Southwark Bridge London SEl 9HS Telephone 020-7717 6000
TWJ THE WELD G TlTUTE Abington Hall Abington Cambridge CB16AL Telepbone 0 J223 89162
Publication DatJ Oil w~ldll1g of lhermopla lics
59
DW154 wciiwlioll for Plastics Ductwork
A -=--DIX
Factors
Specific gravity shy pp = 091 approx UPVC = 14 approx
Some miscellaneous conversion factors
To convert
Length Inches to millimetres Feet to metres
Multiply by
2540 03048
To convert
Millimetres to inches Metres to feet
vIultiply by
003937 3281
Area Square inches to square millimetres 6452 Square millimetres to square inches 000155 Square feet to square metres 00929 Square metres to square feet 10764
Volume Cubic feet to cubic metres Cubic feet to litres Gallons (UK) to litres
002832 2831 4546
Cubic metres to cubic feet Litres to cubic feet Litres to gallons (UK)
35315 00353
022
Mass Ounces to grams Pounds to kiJograms Tons to tonnes
2835 04536
1016
Grams to ounces Kilograms to pounds Tonnes to tons
003527 2205
09842
Volume flow Cubic feet per minute to cubic Cubic metres per second to cubic
metres per second 0000472 feet per minute 2119 Cubic feet per mIDute to litres Litres per second to cubic feet
per second 04719 per minute 2119
Motion Feet per minute to metres per second 000508 Metres per second to feet per minute 197
Pressure Inches water gauge to millibars 2491 Inches wateJ- gauge to pascals (Pa) 2491 I Pa = I ewton per square metre = 10-2 millibars
60
Heating and Ventilating Contractors Association Esca House 34 Palace Court London W2 4JG
Tel 020 7313 4900
e-mail contact Itvcaorguk web site wwwhvcaorguk
Fax 020 7727 9268
--------------
DW154 ~(rilic(Iiofl for Plastics Ductwork
e ACKNOWLEDGEME TS
The HVCA records its appreciation and thanks to the many people and organi ations who gave advice and information during the preparation 0 f thi s specification and in pal1icular to those members offor the drafting panel who contributed tbeir time experience and knowledge
DW154 DRAFTING PANEL
Graham Handley (Chainnan)
Me) Clarke
Bemard Coates
John Howes
Me)vyn Sargent
Keith Elphick (Drafting Panel Secretary)
Gareth Keller (Ductwork Group Secretary)
(HVCA)
Heating and Ventilating Contractors Association
Esca House 34 Palace Court London W2 4JG
Tel 020-7313 4900 Fax 020~7727 9268
e-mail contacthvcaorguk website www hvcaorguk
First Edition 2000 copy 2000 HVCA
ISBN 0-903783-31-2
1
6 6
DW154 Specificathm for Plastics Ductwork
s Page
Foreword 3
co PART ONE - TECHNICAL INFORMATION TO BE PROVIDED BY THE DESIGNER Introduction
2 Standards 3 Components 6 4 Particular requirements 6
PART TWO - STANDARDS 5 Application 8 6 Ductwork classification and Air leakage 8 7 Materials 9 8 Ductwork construction and Joint sealing 9
PART THREE - RECTANGULAR DUCTS 9 Rectangular duct sizes 11 10 Construction 11
101 General 11 102 Longitudinal seams 11 103 Sheet jointing seams 11 104 Socket and spigot joints 11 105 Flanged joints 11 106 Expansion joints 12 107 Stiffeners 12
11 Fittings 12 111 Standardisation of fit1ings 12 11 2 Stiffeners 12 113 Split1ers 12 114 Turning vanes 12 115 Branches 12 116 Change shapes 12 PART FOUR - CIRCULAR DUCTS
12 Standard sizes 16 13 Construction 16
131 General 16 132 Sheet jointing seams 16 133 Socket and spigot joints 16 134 Flanged joInts 16 135 Stiffeners 17 136 Expansion Joints 17
14 PART FIVE - HANGERS AND SUPPORTS General 19
15 PART SIX - GENERAL Access I Inspection openings 22
16 Regulating dampers 22 17 Fire dampers and Intumescent sleeves 24 18 Flexible I Expansion joint connections 24 19 Protective finishes 27 20 Connections to bUilding openings 27 21 Discharge Exhaust terminal 27 22 Thermal insulation 28 23 Fire retardant finishes on plastic ductwork 24 Reinforcement of ducts with GRP laminate 25 Standard component drawings and abbreviations
4
~I-------~- --shy
28 28 31
bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull
DW154 SpaiicatiOll for Plastics Ductwork
PART SEVENmiddot APPENDICESmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotAppemiddotndixmiddotmiddotjmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotAmiddotjrieakagefroniductwork middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot49middotmiddotmiddotmiddotmiddotmiddot Appendix 8 Guidance notes for the Transport Handling and Storage of ductwork 54 Appendix C Fire retardant finishes 55 Appendix D Guidance notes for Inspection Servicing and Cleaning access
openings 56 Appendix E Bibliography 58 Appendix F Conversion tables 60
Table LIST OF TABLES _ PART TWO - STANDARDS
1 8Ductwork classification and Air leakage limits PARTTHREE - RECTANGULAR DUCTS
2 Minimum constructional requirements - Rectangular Un-reinforced UPVC and pp 13 3 Fastening centres Rectangular duct flange joints 13
PART FOUR - CIRCULAR DUCTS 4 Standard sizes 16 5 Fastening centres Circular duct Flange joints 17 6 Minimum constructional requirements shy Circular Un-reinforced UPVC 18 7 Minimum constructional requirements - Circular Un-reinforced PPS and PP 18
PART FIVE - HANGERS AND SUPPORTS 8 Hangers and Supports - Rectangular Horizontal Ducts 19 9 Hangers and Supports - Circular Horizontal Ducts 19
PART SIX - GENERAL 10 Minimum constructional reguirements - Rectangular GRP Reinforced ducts 30 11 Minimum constructional requirements - CirCUlar GRP Reinforced ducts 30 12 Standard Abbreviations 47
PART SEVEN - APPENDICES 13 Air leakage rates 50 14 Access requirements for inspection servicing and cleaning 57
LIST OF ILLUSTRATIONS 0 bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull u
Fig PART THREE - RECTANGULAR DUCTS 1-4 Cross joints 14 5-6 Stiffeners 14 7 Tie rod assembly 14 8 Hard and Easy bends 14 9 Turning vanes 15
PART FOUR - CIRCULAR DUCTS 10-12 Cross joints 17 13 Stiffeners 17
PART FIVE - HANGERS AND SUPPORTS 14-16 Support bearers 20 17-18 Vertical ducts supports 20 19-22 Arrangement of bearers and hangers 21
PART srx - GENERAL 23-25 Expansion joints 25 26-28 Flexible connections 26 29-33 GRP reinforced - Cross joints and Stiffeners 31 34 35
Linear Thermal Expansion 34 35
36-77 Typical Design Stress Standard component drawings - Rectangular 33
78-105 Standard component drawings - Circular 40 106-115 Standard component drawings - PlantEquipmentMiscellaneous 46
PART SEVEN - APPENDICES 116 Permitted leakage at various pressures 52
Example of a completed test sheet 53
5
DW154 Specijimrol1 for Plastics Ductwork
ART 1 4
bullbullbullbullbullbullbullbullbull 41
Technical information to be provided by the desmiddotg er to the plastics ductwork cont actor 42
1 INTRODUCTION 11 Thi specificalion relates to the manufa ture
and installation of rectangular and circular 43 ductwork constructed from plastics The selection of construction method is at the discretion of the manufacturer to conform with the performance requirements of the pecified 44 ductwork clas ification Sections 2-4 blow define the information to be provided by the designer
45 2 STANDARDS
21 Pressure classification (Table 1)
22 Leakage classification (Table 1) 46
23 Positive and Negative pressures (Table I)
24 Materials (Parr 2 Section 7)
25 Any special ystem requirements 47
3 COMPONENTS
31 Access and drainage points Number and location of access doors and drainage points
32 Regulating dampers Specification location and mode of opelatioll of all regulating dampers 48
33 Fire stops Stops to meet the requiremen ts of the Authority directly responsible for fire protection 49
34 Flexible joint connections Sp cification and location of any flexible conne tions eg plant or building expansion joint
PARTICULAR REQU REMENTS
Plastics material Type of plastic material from which the ductwork i to be manufactured and detail of ductwork to special requirements not within this specification
Environmental Env ironmental conditi ons inside and sULToundillg tJle ductwork
Airflow Design airflow volume for all mam ducts branches and air tenninals
Pressurevelocities Design air velocities and pressures for all main ducts principal branches and tenninals
External thermalacoustic insolation he extent and type of insulation to be
provided by others should be stated including full specification for application and installation
Spark testing U spark testing is required the designer shall identify land mark in the contract programme for testing to be undertaken ie manufactur installation corrunissionjng
Air leakage testing The extent of any air leakage testing if required While it shall be mandatory for highshypres ure ductwork (a defined in this specification) to be tested for air leakage iu accordance with the procedure set out in DWI43 A Practical Guide to Ductwork Leakage Testin2 no such te tin of Jaw-oro
mediam-pres Llr duct work is requjJmiddoted
Identification Details of colour coding or identification if required For furth r information see HVCA publication DWl44 Appendix B
Solvent~fomes
Details of design criteria used or adopted to avoid the trapping and discharge of liquid solvent fumes or gases
6
~--
DW154 Specificatio1l for Plastics Ductwork
410 Protective finishes (Part 6 Section J9) Detai Is and specification of any protective finishes
411 Fire retardant finishes (Part 6 Section 23) The extent and limits of protection for any fire retardant finishes on plastic ductwork (Specific references must be defined)
412 Controlssensing equipment Details of positions and fixing configuration of all sensors and test points to suit specialist contml and sensing equipment
413 Special supports (Part 5 Section 14) Details of any spanning primary secondary steelwork or special support requirements not specifically covered by Section 14
414 Attachment to building structure (Part 6 Section 20) Specific requirements for the junction of ductwork and associated components to opening hou1d be detailed and specified with the limits of responsibility defined
Tbe design and provision of penetrations and associated framings are outside the scope of this specification
415 Ductwork layout drawing Details of any special requirement$ relating to CAD scales etc It is common practice and cost effective for duclwork manufacturers to utilise their approved ductwork layout drawings as a basis of their manufacturing installation information by adding the necessary details to the same drawin2 Scales of 150 or smaller may preclude tJlis practice therefore larger scales might be more appropriate The final choice of manufacturing installation scales shall be left to the ductwork contractor
416 Other requirements Details of any requirements far the ductwork not in accordance with the provisions of tbis specification including any modified construction required to conform with any requirements cancerning external ductwork (See 53) or to meet the regulations of a local autbority or athcr controlling body
4 7
Clause
Reference to designer In consideration of the foregoing reference is also made to the designer in the following c1ausesshy
Page 52 8 53 8 106 12 1072 12 111 12 131 16 1352 17 136 17 141 19 144 19 145 19 147 20 152 22 161 22 1631 23 1634 23 171 24 173 24 174 24 181 24 182 27 191 27 211 27 222 28 223 2R 231 28 252 31 Appendix A 49 Appendix B 54 Appendix C 55 Appendix D 56
7
DW154 Spaijicllliflll for Plastics Ductwork
PAR 2 54
Standards
5 APPLICATION
51 This specification sets out minimum requirem nts for tbe manufaclure and in-tallation of ductwork for commercial and industrial fume extraction and exhaust 5y terns made from any of th material listed in Seclion 7 and being within the limit of ize andor material Ihickness speci led in Ihe relevant tables Normal ambient operating temperatures are assumed within the pressurevelocil limits and the limits of air leakage for the various pressur classes prescribed in Table 1
52 Thi specill alion is inlended to apply to ductwork handling fume-laden air which are polluted or is otherwise exceptional in respect of temperarure or humidity (including aturated air) for dllctwork wber the external
surface are exposed to a hostile environment The design construction installati n supports and finishes in such case should be giv n special consideration b the de igner in relation to tbe parti [lIar requir ments of each application
6
61
53 TIlis specification is sllitabl for ductwork expo ed to external atffio phere The designer will need to ~ive sp cift details of any special finish constlUction (See eetiar J9)
62
This specification i ba ed on duct operating environments of not less than - 100e and for
PVC (non GRP reinforced) nor exceeding 40degC UPVC reinforced wilh GRP not exceedin cr
600 e PPS and PP not exceeding 60deg FBPP reinforced witb GRP not exceeding 70degC Systems required to operate at temperatur outside those d tailed above aJthough outside of Ih scop of Ll)is specification are Dot precluded but the ductwork hould be designed from fi rst principle Ilaving regard for the physical mechanical and chemical properties of the material It mu~t be noted that the cOlTosive re i tance of all the above m terials will decrea e at temperatures approaching 5deg to looe below the parent materiaL beat distonion point Further guidance on temperatup effect is provided in Fig 34 Linear Tbennal
xpansion and Fig 35 Typical 0 ign Stres es for VC and PP
DUCTWORK CLASSIFICATION AND A R LEAKAGE
Classification and air leakage limits Duc work la sification and air leakage limitmiddot are eL out in Table 1
Compatibility with CEN The leakage fa tor u ed in able 1 for Classes A Band C ~u-e the ame as those for the cIa e similarly de ignated in th E Document Pr E 12237Pr L507
Table bullbull uctwork Class icati nand ir Leakage Limits (Reproduced from DWI144j
Ducl pressure class
1
Low-pressure -Medium-pressure -High-pressure
-I
I Class A Class B
Class C
Static pr sure limil Air I akage LimitMaximum air
litres per ltccnno per quarevelocity
Positive Negalive metre of duct surface areu
2 4 5 ~ -Pa Pa
f-m1s
0027 X pors500 10500 --1000 0009 x po6~750 20
0003 x pO652000 750 40
Where p is he differential pressure in pascals
Nole Tllls specification DWl54 onJy covers construction up to 1500 Pa
8
- - shy -~----
- shy
DW154 SpeciiCfllioll for Plastics Ductwork
63 Leakage at various pressures and other 110 mm to 600 mm dia (Dimensional rela tionships tolerances to DIN 8062) Applying the limits specified In Table 1 Appendix A (Table 13) sets out the permitted 74 PPS (Forms aailable) leakage at each of a serie of pressures up tu a maximum for each class Incloded in that 741 Extmded sheet in thickness 3 mm to Appendix is a graphical presentation of the 12 mm (Dimensional tolerance to pre urelleakage relationship DIN 53479)
DWl143 A Practical Guide to Ductwork 742 V series tube in sizes 1] 0 mrn lO 630 Leakage Testing provides detai Is of the basis mm dia and fittings in size I 10 mm for the leakage limits specified in Table 1 to 400 mm dia (Dimenional
tolerances DIN 53479) 64 Air leakage testing
Air Jeakage testing of low and medium 743 All PPS material used hall be pressure ductwork is not mandatory under compatible and comply with DIN tJlis specification Air kakage testing of high 4102 part B and SS 476 part 7 class pressure ductvork t mandatory under this 4 PPS material should not be used for specification and for details of testing external applications vithout suitable procedure refer LO DW143 A Practical Guide protection (See Part 6 section 19) to Ductwork Leakage Testing
744 It should be noted thal PP is not fully 7 MATERIALS compatible wilh PPS
71 Application 75 FBPP (Forms aailable) This specification applies to ductwork constructed from materials as defined below 7 51 Sheet in thickness 3 mm to 9 mm or equal Minimum material thickness is to be taken a a nominal thickness as Tables 267 7 52 Continuous roll form in thickness 2 10 amp 11 AJJ UPVC materials ued shall be mm to 4 mm low flammability selfextinguishing compatible and UV stable with pigment colour to RAL 7 53 This particular material is specifically 7011 and DIN 4802 B 1 designed to be externally reinforced
with GRP (See Section 24) 72 Types
The materials covered by thi specification are 76 UPVCGRP abbreviated herein as foIlowsshy This is a form of composite lamjnate used (UPVC) Unplasticised polyvinyl chloride where improved mechanical trengtb UV (PPS) Self eXlioguihing polypropylene stabilisatiolJ or fire retardence is required (PP) Polypropylene (GRP) Gla s reinforced plastic 77 UPVCIFOAMJGRP (FOAM) Rigid polyurethane self FBPPFOAMfGRP
extinguiShing foam This is a form of composite laminate used (FBPP) Fabric backed polypropylene sheet where insulation andor support is required for
special applications 73 UPVC (Forms available)
8 DUCTWORK CONSTRUCTION 731 Extruded sheet in thickness 3 mm to AND JOINT SEALING
12 mm (Dimensional tolerances to DIN 7748) 81 Ductwork construction
The election of longitudillal cross joint and 732 V series tube in sizes 110 mm to stiffener types within the criteria laid dOT1 in
1AOO mm dia and fittings in siz~ Part 3 amp 4 shall be used as a minimum standard
9
DW154 Spet((icatioll for Plastics Ductwork
82 Joint sealing and sealants 8226 The joint mu t be held in po ition ror at leamiddott 5
821 General minutes A jig should be The integrity of the ductwork used jf nece-ltsary to ensure depends on the successful applicatioll that no twisting force i of tbe conemiddot t jointing metbod appl ied to th joint during
the period 822 Solvent cementing
Solvent cementing a atisfactory 8227 Once made the joint method of jointing circular UPVC should not be exposed to socket anu spigot or leeve joints a undue force for eight certain solvent based cement horn shy hour Tb full strength of geneously bond the PVC surface the jOjJlt is not achieved in providing uitabl joints Solvent less than twenty-four cementing i not practicable with PP hours because of its hioh resi tanc to solvents The procedure recommended OTE SOLVENT CEMENT JOINTING by the cement manufacnJrer should METHODS ARE TOT RECOMshybe followed but the following points ME DED FOR RECTANGULAR are important DUCT SECTIONS
[N ALL CASES S ALA MATshy8221 Clearance between ocket ERlALS MUST BE APPLIED
and spigot must be STRICTLY IN ACCORDA CE minimal because of the WITH THE MANUFACTUR ~RS
lirnited gap filling propshy 11 STRUCTIO SAD OSHH ertie of the cement ASSESSMENT
8222 Inside edges of sockets and 823 Hot air welding utside edge of spigot VC and pp a be welded by
shouJd be lightly chamshy Llsing the hot ga Ifil1er rod meUlOd fered ltmd thoroughly cleaned described helow
8223 Mating urfaces should be 8231 The welding gas can be cleaned using a proprietary nitrooen or compressed air solvent cleaner to remove and shltlll b fIltered free grease and slightly etch the from suspended water oil surface vapour and particulate
matter 8224 The cement should be
applied a quickly a 8232 The filler rods shall be possible to the socket and made from material to r pigot over the full area of compatible with the matshythe mating surface are eriaJ being welded should be taken to avoid the use of excessive 8233 Butt weld joints shall be cement bevelled to an included
angle of 60deg to 90deg and 8225 The posi liolling of the joint where po sibl welds shall
mUSl be achieved immedshy be fully penetrated from iately after the cement i both ide of the work applied aJld surplus cement removed
10
DW154 Specificatiol for Plastics Ductwork
8234 The joint face and the filler rod surfaces must be clean and grease fre and preferably roughened b shyfore welding In particular any deposited filler rod that is charred mu t be scraped away before additional runs are added
8235 The numbers of runs of fi lIer rod shall be sufficient to give a thiekne s of era s section of the veld at least equal to the thiekn s of the sheet
8236 Where high frequency park testing i specified lhi shall be undertaken in accordance with tbe weldshying in tmction handbook
Note A full descriplion of welding method is given in the Welding Institut handboo entitled Data on Welding of Thennoplastic Relevant BS amp CE Standards are prEN 12814-1 amp 2 prE 13067 and prE 13100-1
824 Completion of compo ite laminate joints Following solvent ementing or hot air welding of joints campi tion of any specified external laminate shall
carried out to maintain thebe
825
integrity of the construction (S 8227)
Gaskets These can be fabricated from various materials in the form of a pre-formed roll she t or trip applied between opposing faces of fbnced ross joints It i a visable to select material r commended by th ga ket manufacturer for the pecific appucation intended
PART 3
Rectangula ucts
9 RECTANGULAR DUCT SIZES
91 This specification covers duct size up to a rnLltimum longer ide of I -00 mm Duct size with an a peet ralio greater than 4 I ar not recommended Although they offer no problems of construction they increase friclionaJ resi tance and the pos ibility of Dois
10 CONSTRUCTION
101 General Th minimum constructional requiJement r r UPVC and PPPPS un-reinforced are hown in able 2
102 Longitudinal seams Longitudinal seams should Dot be located at corners or in the underside of the duct
103 Sheet jointing seams Seams shall be joined by continuous filler rod hot air welding or by fl1sion Vi ldiug only other form of jointing are not acceptable
104 Socket and spigot joints Sock t and spigot joints shall be formed by purpoe made double cket pi ces 100 mm long and of the ame thiekne material as the duct welded into position on each standard length of duet forming 50 mm de p sockets prepared and ready for final jointing on site with filler [Od of the ame formulation used for prefabrication (See Table 2)
105 Flanged joints
1051 FJa ges Fabricated flanges shall b con tmeted u ing miniumum of 9 mm thick by 50 nun wide material of matching formulation depending on duel size as hown in Table 2 The flange hall be mounted true and square to the duct surface and w lded on both sides a 103 and Figs 3 4 Alternative con truction Illay be
11
DW154 Spedjicfltiotl for Plastics Ductwork
utilised for attacllment to plant or other equipment
1052 Drillings Drjllings shall be placed to permit clearance to tbe extel11al casing and any reinforcement of tbe ductwork for the application of fastening
1053 Fastenings For nonnaJ application bright zinc plated bolts nuts and vashers hall be Llsed in sizes and pitch centres shown in Tabl 3 Where special conditions prevail consideration of other material finishes such as stainless steel bolpounds nuts and washers may be used In all cases gasket materials as Section 825 shaLL be used
106 Expansion joints Wher the configuration of the ductwork does not provide for movement due to temperature change or where such movement is restricted by branches or attachmenL expansion joints should be specified by the designer (See Section 18 FlexibleExpansion joint connections)
It is the re ponsibilir-y of the designer to identify the positions of any necessary expansion joints hased upon design param ters for the individual systems (See Figs 23 to 25 34 amp 35)
Design ote xamples of expansion joints shown in Figs 23 to 25 are not suitable for movement exceeding 30 mm
107 StilJeners
1071 External stiffeners Shall be fitted as specified in Tables 2 amp 10 and Figs 5 amp 6
1072 I temal stiffeners The u e of internal stiffening or bracing shall be acceptable iJ deemed necesary and approved by the designer (See Fig 7)
11 FITTINGS
111 Standardisation of fiuings The terminology and descriptions of rectangular duct fittings a et out in Section 25 are recommended for adoption as standard practice to provide common terms of reference for desi crners quantity surveyor and ductwork contractors and for those using computer in ductwork design and fabrication
Bend are designated as hard or easy and the e terms as used herein have the folJowin o
meanings
Hard signifies rotation in the plane of tb longer side of the cross ection
Easy signiiies rotation in the plane of the shorter side of the cros section
An example iIlu trating these term ] given in Fig 8
Fitting are fabricated by cutting and welding sheet
112 Stiffeners Shall be as 107 and Tables 2 amp 10
113 Splitters Shall be as shown in Fig 41 and welded as 1003
114 ruing vanes Where square bends are required turning vanes as shown in Fig 9 hall be fitted
115 Branches When fitting branch ducts to a main duct care should be taken to ensure that the rigidity- of the duct panel is maintained in terms of tbe sti ffenillg criteria
116 Change shapes Where a change bape is necessary to acconUllOdate the duct and the cross- ectional area is to be maintained the slope haU not exceed 225deg 011 any side (See Figs 52 to 56) Where a change in shape includes a local reduction in duct cras - ectionaJ area the slope should not exceed ISO on any side and tbe reduction in area should not exceed 20 Where tceper angles are necessary due to ile
12
DW154 Spec([icatirJ1l for Plastics Ductwork
restucllOn splitters shall be provided Taper Transformation pieces from circular 10 square pieces reducers and transformation piec s or rectangular shall be made as long a shall be manufactured from the tbickl1 s of p sible and uJe angl ball be uot mor than material specified for the larger size ducl 225 (Fig 55)
loon Pa 1500 Pa
2 3 4 5 6 mm mm mm mm
3 socket amp spigot - - -or tlanged
as Figs 1 2 3 401 to 600 45 flanged 50 x 9 flat 1200 800
50 x 9 flat welded both sides a Fig 3 as Fig 5
601 to 1000 45 flnged 50 x 9 flat 800 600 50 x 9 flat welded both sides as Fig 3 as Fig 5
1001 to 1500 6 anged 75 x 9 flat 600 600 75 x 9 flat welded botb sides as Fig 3 as FieJ 5
or or 70 x 70 x 9 angle 50 x 50 x 5 angle
as Fig 4 welded both sides as Fig 6
N t For constructional operating temp rature limits refer to Part 2 Clause 54
Longer Pitch Bolt Size
Side max 2
mm 1m mm Up to 400 100 8 with washers 401-600 tOO 10 with washers
601middot1000 100 10 with wash rs 1001-1500 100 10 with oycrsized
washer
13
Table 2 inimum con tructional requi ments - rectangUlar nmiddotreinforce UPVC and pp
Joints Sliffeners Maximum spacinOLonger Side MillirnUlll She t between
Thickness Joint~S(iffi ners
mm Up to 400
DW154 SpedflCiltion for Plastics Ductwork
Cross joint - recta gular ducts
Fig 1 Socket and spigot joint (UPVC and PP)
Conlinuou weld joint on sile onlinuou- wcld
CT~r~T2
Fig 3 Flange joint (UPVC and PP)
ontinuou weld
Fig 2 Socket and spigot joint (UPVC only)
Fig 4 Flange joint (UPVC and PP)
S iffeners - rectangular ducts
Fig 5 Flat Fig6 Angle
Oatim wo]
Fig8 Bends - examples of hardTie rod assembly and easy
Hard
Fig7 With spacers Easy
4
DW154 Speci(uariml for Plastics Ductwork
Fig 9 Turning Vanes
HOWl G TYl AL EXAMPLE OF FOCI G
15
Ma vane length shy 615 mm
Example ofbraemg when V1IIle length exeeed max pennined Ahematively two banks of ncs fixmg the centre rail together at ] 50 mm nrrcs
U~_II---- fixed to dnct wall both CDds
bLEVATION
vane
Maximum distance between centrc oflUming vanes should [Jot exceed 60 mm pitch
DW154 SPCCijicllfiull for Plastics Ductwork
practice to provide common terms ofPA T4 reference for designers quantiry urveyor and
Circular Ducts
12 CIRCULAR DUCT SIZES Th duct sizes [n Table 4 have been selected from the ISO and C standard ranges as the 132 preferreod sizes
Table 4 Circular ducts shystandard extruded tube sizes
133 Extruded tube
ISO Standard Sizes (Nominal Diameter) 11
Wan Wall Thickness Thickness
mm mm mm mm 110 500 4022
I25160 600 50 I25200 630 60
225 25 700 60 13425250 800 63
280 900 70 315
23 23 80
355 1000
25 1250 104 400 32 1400 108 450 35
Note The above sizes are subject to normal manufactl1ring tolerances Other size may be available in varying wall Lhicknesses and subject to test and operational pressure
13 CONSTRue ION
13 General Tllis specification covers duct sizes up to a maximum diameter of 1500 mm The minimum constructional requirements for UPVC amp PPPPS un-reinforced ducts sball be as Tables 6 amp 7
ductwork contractors and tho e using computers in ductwork design and fabrication The requirements for circular duct fittings apply throughout the size ranges covered in this specification
Sheet jointing seams Seams shall be joined either by continuous fLiJer rod hot air welding or by fu ion welding Other forms of jointing are not acceptable
Socket and Sl)igot joints Socket and spigot joints shall be formed by purpose made double socket pieces 100 mm long and of the same thickness material as tJJe duct welded into position on each tandard length of duct forming 50 mm deep sockets prepared and ready for final jointing on ite with PVC adhesive andor fill r rod of the same formulation used for fabrication
Flanged joints
1341 Flanges abricated flanges shall be conshy
structed using minimum of 9 mm thick by 50 mm wide material of matching formulation depending on duct size as shown in Tables 6 amp 7 The flange shall be mounted true and square to the duct surfaces and welded OD both sides a 103 and Fig 12
1342 Drilliogs Drilling ball be placed to permit clearance to the external casing and any reinforcement of the ductwork
1343 Fastenings For normal application bright zinc plated bolts nuts and washers hall
16
For srualler diameters preformed fittings are available otberwise fitting are fabricated from segments of duct or sheet welded together
The terminology and description of circular duct tiltings as set Ollt in Section 25 are recommended for adoption as standard
be used in sizes and pitCh centres shown in Table S Wh re special conditions prevail consideration of other material finishes such as stain le steel bolt nuts and wasbers shall be u ed In all ca cs gasket materials as Seciion 825 shall be USed
DW154 Speciliwriml for Plastics Ductwork
135 Stiffeners
1351 External stiffeners Shall be fitted as specified in Tables 67amp 1 I and Fig 13
1352 Internal stiffeners The use of internal stiffening or bracing hall be acceptable if deemed neces ary and appn ved by the designer
f 36 Expansion joints Where the corrfiguration of the ductwork does not provide for movement due to temperature
Cross joints - circular ducts
change or where such movement is restricted by branches or attachments expansion joints should be fitted (See Section 18 Flexible Expansion joint connections)
It is the responsibiLity of the designer to identify the position of any necessary expansion joints based upon design parameters for the individual systems (See Figs 23 24 2534 amp 35)
Design Note Examples of expansion joints shown are not suitable for movement exceeding 30 mm
Fig 10 Socket and spigot joint (UPVC and PP)
ConLinuous weld joim on ite Ontinuous weld
crlr~l
Fig 12 Flange joint (UPVC and PP)
Continllous wcld
boil
Continuous weld or Solvelll cement
Solvelll ccmcnl joim on sile
Fig 11 Socket and spigot joint (UPVC only)
Stiffeners - circular ducts Table 5 Fastening centres shycircular duct flange jointsFig13 Flat
flat conljnlJou~ly welded Diameter Pitch Bolt Size
max
1 2 J 11
1 shy -~
mm mm mm Up to 600 100 8 with washers
601middot1000 100 10 with washers - ---I
1001middot1500 100 10 with oversized washers
1
Minimum offourfixings
17
DW154 Specifiiutiofl for Plastics Ductwork
Table 6 constructional quiremen s - circular unshy inforced U VC
Diameter Minimum Joints Stiffeners Maximum spa ~in r
Sheet between Thickness Jointsl tiffcners
1000 Pa 1500 Pa
1 2 3 4 5 6 UD mm mm mm mm
UO to 600 3 socket amp spigot as Figs 10 11
or fla ged Fig 12
601 to 1000 45 socket amp spigot 50 x 9 flat 2400 2400 as Figs 10 11 welded bo sides
or Oanged as Fig 13 as Fig 12
1001 to 1500 6 Hanged 75 x 9 flat 1200 1200 as Fig 2 welded both ides
as Fig 13
Applies 10 Tables 6 alld 7
Note 1 For constructional operating temperature limit refer to Part 2 luu 54 2 To allow for conicleration or extruded se lions or fabricated component the materia] tllicknes i hawn a nominal
Table 7 Minimu onstrucfional requirements shy circular un-reinforced PPS and
Diameter Minimum Joints Stiffcners Maximum pacio Sheet between
Thickness Join sStiffener 1000 Pa 150n Pa
I 2 3 4 6 mm m m mm
110 to 500 3 socket amp spigot as Fig 10 or flaoged as Fig 12
501 to 750 45 ocket amp spi~ot
as Fi 10 or Uanged as Fig 12
751 to 1000 6 tlanged 50 x 9 Oat UOO 12 0 as Fig 12 welded nth sides
as Fig 13 1 1 to 1250 6 flanged 75 x 9 flat 800shy 800
as Fig 12 welded both sides as Fig 13
1251to~ flangcd 75 x 9 Oat 600 600 as Fig 12 welded both sides
as Fig 13
18
DW154 Sped(icalirm for Plastics Ductwork
PARTS
Hangers an Suppo ts
14 GENERA
141 Supports are an e sentiaJ part of me ductwork system and their supply and in tallation are normally the responsibility of the ductwork contractor The principl s are a I-rvCA publication DWIl44 Part 6 Section 19 and should be read in conjunction with this document
Design Note Designers may pecify specific requirements wbich will supersede guidance given in DW144
142 Rectangular ducts abl 8 give the- minimum requirements for
hanger and supports for un-reinforced ductwork
143 Circular ducts Table 9 gives the minimum requirements for hangers and upports for uD-reinforced ductwork
144 Vertical d cts The design of supports for vertical duct is dictated by site condition and where practical duc hould be upported at 4000 mm interval or where tbey pa s through a floor (but n ver exceeding 4500 mm) see Figs 17 amp J8
145 External ducts Where ducts are external to buildings and may be ubject to wind loading support should be plac d so as to restrain ide tl1ruSt and should allow axial movement as neces ary It is the respon ibility of me de igner to calculate the effect of the particular prevailing condition and to define any special upport requirement
146 Expansion joints Support shall be designed to permit axial movement only and shall e provided on eitl1er ide of expansion joint
I 1shy
I~
mm -Jp to 400
401 to 600 601 to 1000
Table B Hangers and Supports - rectangular horizontal ducts
Hanger Bearer Drop Roll Formed Rod
Long r Side
Cbannel ~-shy ~
---shy
Maximum ~pacing
4 52 3 _ -c Fig 15 - Figs 14 15 16 amp 2J
shy
mmm mmmm 240025 x 25 x 16 40 x 20 x 15 8 240040x20x15 40x 20 x 15 10 240040 x 20 x 1~510 40 x 20 x 15
shy
I
40 x 40 x 15 40 x 40 x 15 24001001 to 1500 I 10
Table 9 Hangers and Supports - circular horizontal ducts
Longer Side Hanoer Split Clips Maximum spacing Drop Roll f-ormed and Wrap-round Rod ~hannel Hang r
2 3 4I Fig 1920 amp 22Fig I
mm mmmm mm mm 25 x 25 x 15 IIp to 355 8 40 x 3- --1-_ 2400
2400
2400 2400
70x 6
40 x 5 SOx 5
40 x 20 x 15 40 x 20 x 15 40 x 40 15
10 10 10
356 to 600 601 to 1000 1001 to 1500
19
DW154 Spccijicutioll for Plastics Ductwork
147 Protection specification Any special coatingpaint Unless otherwise stated all support shall be finishes for protection against hostile manufactured in material as specified in this environments shall be advised by the designer
SUPPORT BEARERS
~ 14 Flg16 Inverted profile
angle I ~lIed steel
channel (alternatives) Fig 15 Profile channel (alternatives)
TYPICmiddotAL VERTICAL DUCT SUPPORTS Flat bar clipStiffening frame Outline ofinsulation stiffening frame or tlanged joint (if applicable) or flanged joint
Stiffening framc or flanged Joint
~~-I ( ee notes 10) I
r--~ -++- ~--4==J===4~---
Fig 17 Vertical rectangular ducts Fig18 Vertical circular ducts
The support bearer which depending on ducti tructural opening size could be either channel or angle section may be ll1ilised in any of the following arrangementsshy
a) To support the underside of a flat bar clip in halves (circular)
b) To support the underidc of either the stiffening frame oftbe flanged joint ofaoy duct section
c) To support either a stiffening frame Or a flanged joint below nsing drop rod srudding
20
DW154 Spediraiml for Plastics Ductwork
Arrangement of bearers and hangers (to be read in conjunction with Table 8 amp 9
wbich list material sizes relative 10 duel izes)
KEY Limits refer to actual duct size - insulation is additional - Typical
attachmentv -Atta hment t strucUlrcI to strucUlrc
I I
I - Flat Bar
I - Drop rod or - utlinc of lllddmg In ulillwn (if
applicable)
Alternative 7 drop rod or rt------------ 1 studdmg q I
I I Rectangular
ii i n 1
Fig 21 Rolled or profiled bearer Limit oncFig 19 Wrap-round hanger Limit 55 DIA
V v Drop rod orAllernaUC 1 1 tudding
drop rod or 1
-- -- 1studding and elded bas 1
I I0 -_
Limit 355 DIA Frg 22 Split clips Limit 1500 DIAFig 20 Flat strap hanger amp split clips
21
DW154 Specification for Plastics Ductwork
6PA deElned in J62 appropriate to the airflow pressure acoustic temperature and corrosion
General
15 ACCESSl SPECTION OPENINGS
151 General These are for inspectionservici ng on 1y
HVCA publication DWIl44 Part 7 - General Section 20 sets out the requirements for access applicable to this specification
152 Cleaningmaintenance Designers shall take specialist advice and then stipulate their requirements for the periodic internal cleaningmaintenance of ductwork and of the consequent need for adequate access for specialist cleaning equipment including the size type and locationfrequency of the actual access openings required
Appendix D sets out guidance notes for the consideration of cleaning access and also makes reference to the HVCA publication TR 17 Guide to Good Practice Cleanliness of Ventilation Systems which covers the su~ject
in greater detail
Note A majority of in tallations in which plastic ductwork is used are considered to have a nigb operational risk potential and provision of access should address this
16 REGULATI G DAMPERS
161 General Balancing dampers and control dampers are elements inserted into an air di tribution system or element of an air distribution sy middottem Balancng dampers permit modification of the air resistance of tbe system and consequently cbanging of the airflow rate Control dampers control tlle airflow rate and may in addition provide low leakage closure of the airflow
The deigner shall specify damper locations taking into consideration that good design practice requires a minimum of five times the diameter or width of the shortest side of uninterrupted flow between plant connections and the damper and select the damper type as
characteristics
1611 Balancing damper To achieve the required distribution of air in the ductwork system at inlets andor outlets for [hi purpose the damper blades are set and Jocked manually in position between fully open and fully closed
1612 Control damper To secure dynamic control of the air now in the ductwork system In thi function the damper will always be power actuated and may require to be modulated between fully open and fully closed and to be capable of taking up any position between these extremes In the fully open position the damper should have a minimum pressure drop In the fully closed position it will not necessarily achieve a complete shut off
162 Types of airflow control dampers Airflow dampers of various types are available for specific purposes as follows
1621 Single - blade dampers Single-blade dampers shall consist of a si ngle pi voted blade cOlllained withjn a casing or section of ductwork The blade shall be adjustable tbmugh a nominal 90 angle by means of a quadrant or similar operating mechanism Where automatic control of the damper is required the spindle shall be extended to enable a powered actllator to be mounted
Single-blade dampers shall have a maximum duct width of 400 nUll and a maximum duct height of 400 mm for rectangular ducts and for circular ducts a maximum diameter of 400 mm
1622 Multi-blade dampers Multi-blade dampers shall consist of a number of pivoted blades contained within a casing The blades shall be
22
DW154 Sedicalirm for Plastics Ductwork
adju table through a nominal 90deg angle simultaneously by intershyconnected linkage or gears connected to a quadrant or similar operating mecbanism Where automatic control of a damper is required a spindle shall be extended to enable a powered achlator to be mounted
There is no restriction on the size of duct in which multi-blade dampers or damper assemblie may be u ed Where dampers are required for blade lengths in excess of 750 mm the blades should be suitably reinforced or supponed 0
individual damper blade should exceed 200 mm in width
1623 Iris dampers Lris dampers shall consist of a nUlllber of radialty interconnected blades which open or close within a casing with duct COlll1cctions The blade shall be simultaneously adjusted by a quadrant or similar operating mechanism
Iris dampers shall be installed as specified by the manufacturers operating and installation instructions where the product is unidirectional with regard to airflow
lris dampers are available for circular ducts only in diameters up to 250 mm (it should be noted that the damper casin i appro)(imately twice the diameter of the duct)
1624 Backdraught dampers Air pressure operated uni-directional rectangular (single or multi-blade) with adapters if fitted to circular ducts
1625 Slide and blast gate dampers A damper [lsed as a shut off facility with an externaJ Lide bousing allowing the blade configuration to be fuJly inserted to fully extended for maxiDlUlll air flow
163 Construction
1631 Materials All products shall be protected against cOHosion as necessary and supplied in a fully finished condition as specified by the designer
1632 Dampers used in low and medium pressure systems The following recommendations apply to dampers forming an integral part of ducrwork with pressure classifications A and B air leakage limits
The dampers shaH be constructed to minimise distortion and prevent jammin in operation Th blade shall be sufficiently rigid to minimise movement when in the locked pOSitiOLl
The blades shall be securely fixed to the operating mechanism All balancing dampers shall have a locking device located on the outsid of the case and shall giv clear indication of the actlwl blad position All penetrations of the duct shall be fitted with suitable seals where necessary
1633 Dampers used in high pressure systems Regulatino- dampers used in duc[work sy tems to pressure cJassification C shall meet tbe construction requireshyments specified in 1631 and 1632 with operating mechanisms out of the air-stream
1634 Proprietary types of damper The use of any specific type of proprietary damper shall be confirmed by the designer In all cases proprietary dampers shall meet the relevant requirements of thi specification
1635 Damper casings Duct damper casings hall be constructed to meet th mllllmum
23
DW154 SpeciJimlioll for Plastics Ductwork
leakage Iim its sp cified for th c1uctwork ystem to which tbey are installed
In order to apply the square metre leakage calculatio as detailed in DW143 A Practical Guide to Ductwork Leakage Testing the reference casing area ball be taken as the perimeter ize of lh damper IDultipli d by the equi alent length of Imetr eg an 800 mm x 400 mm duct damper hall have a surface area for casillg leakag p donnan calculated as follow (2 x 08) + (2 x 04 x I
=24m2 casing area
Other pelforlllance ancl rating test methods for damp f and valves are specified in ISO 5129 and BSIE 1751 and are referenced belm a) Leakage past a closed damper
alve BSIE 1751 b) low ratepre sure requirement
characteri t cs BSIE 1751 c) Operational torque le ring
BSEN 1751 cl) Thermal transfer testing
BSIEN 17 I e) Reg nerated sound power levels
ISO 5129
164 Installation Dampers shall be imaalled in accordance will) any re Ievant ISO EN or British Standard 10 aJ bUT lcling regulation and national code of practice as well as the manufacturers recommendations
17 FIRE DAMPERS AND INT MESCENT SLEEVES
171 General Damper or sleeves arc requiTed on duct y~telll where the designer has -tjpulated the
duct wiU penetrate a fire compartment in the majority of application tbermopla ti ductwork is ugtecl where contamlDated corro ive or otherwise exceptional fumes are concerned it is preferable to use tire damp r which are externalJy mounted ie of the intmnescent operated crush typ
24
72 Fit-e rating The damper assembly should have a fUT
resi tance ratin o equal to that of the fir ban-jer it penetrate and ball be fire tested and rated to the timetemperature curv of B 476 Part 20 and 22
173 Intumescent sleeve At the time of writing this specification qualified test results were available for rectangular dampers and circular dampers up to 55 mm diamet r Manufacture have indicated that they are able t provide speci fications for other size and diameters This infonnation should be confirmed b th de igner Various type are available includino
tho e incorporating ruechanical closing plate and those operated anI by expanded iJllUme c nt media
In all ca es fire damp rs and intnmeBcen leeves shall be supplied and in taUed in
accordance with the manufacturer iJlStructioos and COSHH a essm nt
174 Other types Fire dampers of mious types are availabl for specific purpose~ ee HVCA publication DW144 The de igner should )lot (hat materials for con lt1Jction bould be uitablc for the par1icular application
ALL C SES FIRE DAMPERS AND fNT MESCENT SL _VES SHALL HE S PPLTED AND INSTALLED IN A ORDA CE WITH Tf--IE MANUshyPACTURERS STRUCTTONS AND COSHH ASSESSMENT
18 FLEXIBLEEXPANSION dOINT CONNECTIONS
181 General ploperties Tbe material u ed for flexibleexpan ion iojnt~
mu t meet the design r requirements for temperature air pressllrelfe resistance applicable to pl astic duct sy tem vibration and noi e br akout when incorporated into a jointconnection and shall comply ith lh standard of air-tigbtne specifi cl for the duct work sy tem of which it fOlms part (See Figs 23 24 5 26 27 amp 28 for typical con truclion clelai Is
DW154 SJecilimtol for Plastics Ductwork
Expansion joints
Fig23 Moulded bellows type (rectangular and circular)
Fig24
~F aiblc sleeve
__ liding sleeve
~~~~
Sleeve type (circufar)
Fig 25
AIRFLO
COnlinuou~
weld~
Flexible Iceve
PV A HOWN pp SE BACKING FLATS AS FIG 2
Sliding lee c Co1linuou
weld
Flanged sleeve (rectangular and circular)
25
DW154 Specificatiol for Plastics Ductwork
Flexible con ections
Fig 26 Flexible sleeve with clips (UPVC and PP)
--__ Flexible I eve
I
I
I CODn clioD to plant ~
Band clip
Fig27 Welded flexible sleeve (UPVC only)
Plastic)sed PVC slceve ~-- onll11uo1sly welded
onrreclion to planl ~
Fig28 Flanged flexible connection (UPVC and P )
t sp dally moulded flexible flanged connCClitlll
boil
C)nneclion to plant ~
26
DW154 Specificotiol for Plastics Ductwork
182 LOClt1tion Flexible joint are typicltllly lIsed at building expansion joint and fan inletsoutlets Any others required should be indicated on the de ign drawings Care should be taken to maintain alignment across jointsconnections
183 Length Flexible Jomts shall be kept as short as pra middottieable above a minimum eft ctive length of SO mm In no ca e shall a flexible joint exceed 250 mm in lengtb
184 Connections to rectang a ducts With flanged rectangular connections Ule tlexible material shall be held in pLace with flat pIa tic strip of not less U1an 6 mm thick ltlttached to the flanges using uitabJe fixings The more heavy weight type of fleAible mateLial may also be obtained formed into a channel ection with corners fitted to give a neat air tight j int For pigot connections the Be ible material shall b held in place with flat pIa tic trips n t less than 6 mm thick
t 85 Connections to circular ducts With tlanged circular connections the flexibl material shall be held in place with flat plastic backing strips or proprietary clip bands with screw or toggle fast ners
186 Welded flexible connections (Rectangular and Circular) Where the parent and llexibl material are from imilar ba ed products they can be joined to the duct u ing the welding method described in Section 823
19 PROTECT VE FINISHES
191 nles otherwise stated all ductwork shall be mallllfactured in mat fial as pecified in tbis specification Any special coatingpaint fmishes to be provid d by the duct work contractor sball be advisd by th de igner
20 CONNECTIONS TO BUILDING OPENINGS
201 Fanning and finishing building op nings are not the repoJlsibjlity of the duftw( rk contractor and the note that follow are for guidance purpo e only
2011 Openings in brick block or concrete walls shall have inset frames to provide a suitable means of fixing grille louver masking flanges or the tlanged ends of ductwork The illset frames shall be conslnlcted to maintain the structural int grity of the wlll and where applicable cavities shall be suitably lined
2012 Openin s in dry linino partItIons shall have inset frames a 2011
2013 Openjngs in cladding walls and roofs shall have flaoged leevesframes to provide a suitable means of fixing a 2011
2014 Horizontal and vertical opening xposed to oLltside atmo phere hall
be provided with a suitable weathering fini h at the external face especially where profiled cladding is used
2015 Timber framed op nings are not permitted In fj re compart ment barriers
202 Ductwork connections to building openings hall have a flange of suitable profile to permit practical fixing to the openillg frame In selecting the profile consideration shall be given to Tabl~s 2 and 10 in this specitication relating to duct ize and rating Gasket strip or sealant shall be ltlpplied between the tJaoge and building op ning frame
21 DISCHARGEEXHAUST TERMINAL
21 Tbese shall be vertical open ended and designed to meet and comply with current r gularions on contaminated flue The designer hall ensure that the de ign and perf rmance i suitable for its intended purpose Examples of some typical terminal designs are SbOiD in Figbull 102 10 bull 104 amp 105
27
DW154 SpedjimioTl for Plastics Ductwork
22 THERMAL INSULATION
221 The provision and application of thermal insulation to ductwork is not the responsibility of the ductwork contractor
222 Where ductwork is required to be preshyinsulated the specification should be agreed with tbe designer
223 Where the temperature of the air within the duct promotes condensation on the exterior surface of the duct and cause moisture penetration througb the thermal insulation vapour scaling may be required and in this case the most important requirement is to limit penetration of the seal
The extent of any vapour sealing of ductwork thermal insulation and the support method to be u ed must be clearly pecitled in advance by the designer
224 For detailed information on the thermal insulation of ductwork reference should be made to BS 5422 1990 which covers the specification for thermal insulation materials on pipes ductwork and equipment (in the temperature range -40degC to +700degC) and BS 5970 1992 which is a Code of Practic for Thermal Insulation of Pipework and Equipment (in the temperature range -lOOdegC to +870degC)
23 FIRE RETARDANT FINISHES ON PLAST C DUCTWORK
231 The designer should note tbat ductwork constructed to DW154 has no teted fire rating or information see Appendix C
24 REINFORCEMENT OF DUCTS WITH GRP LAMINATE
241 General Where ductwork is required in larg T izes than are covered by Tables 2 4 6 amp 7 or with the increased strength sometimes necessary for industrial use external reinforcement is normally pwvided by applicatioD of glass fibreresin laminate
GRP systems will bond satisfactorily with standard UPVC sheet but for pp it is
nece sary to use a specially prepared sheet with a glass fabric backing incorporated dOling manufactllfe
The detailed techniques of fabrication using GRP are outside the scope of this speci lcation but the following notes are offered for guidance of ductwork fabricators
242 Materials
2421 Quality The laminate is made up of polyester resin complying with BS 3532 and glass fibre complying with BS 3496 or BS 3749 The nominal ratio of resin to glass fibre should be 7030 by weight
2422 Minimum properties The laminate shall comply with the followiog mini mum pbysical properties
Tensile strength - 70 MNm Tensile modulus - 7 Gl m Flexural strength - 140 M Im Bond strength (hetween laminate and substrate Not less than 7MNm Bmcol hardnes Not le s than manufacturers specification
The GRP reinforcement educe the expansion of the parent material but the resultant stre ses arc well within rhe strength of the bond However the Iinear thermal expansion curve shown in Figs 34 amp 35 will serve as a guide
Surface resistivity electrkal propcltles and acoustical propertie are similar to the relevanl unreinforced materials The fire retarding properties of GRP may be improved by the use of specialisl laminating resin
2423 Forms available GRP Laminate should be built up from the separate materials ie resin aod glass fibre in the form of chopped
I strand mat or spray ravings
28
DW154 Spcification for Plastics Ductwork
2424 Workshop conditions Polyester resuls are sensItIve to lmperature and the workshop hould b maintained at a temperature of herween 20deg and 25degC HiOh relative humidities and damp onditions should be avoided A good rate of air change must be pro icled pJeferably by m chanical ventilation
2425 Storage of materials Resin and urin o agents shouJd be stored in dark cool condirions away from the working area and in confonnit with statutor requireshyments for tJle middottorage of flarmnable liquid Because of Ule Limited torage lif of the unmixed resin and curing a eot mal lials ~hould be ch eked before use to enLlfe that they are within the manufacturer pe ified sh If life (usually ix month from the dm of manufacrure)
Glass fi re should be stored separately und r clean dry conditions
243 Surface preparafon
2431 UPVC To achieve the specified bond strengtll the urface to which the GRP is applied mut first be thoroughly cleaned and then etched either by mechanical means or by the use of a suitable solvent
2432 pp with glass fabric backing To achieve the specified bond middottrength the fabric backing must be thoroughly impregnated Witll resin
244 Mixing the materials for use The re in 1 a three part mix compri lng base I sin hardener and accelerator The manufactur rs pecj[ied proportions are critical and th llUxmg sequenc pecified must be meticulously foUowed
The resin has a very limited life after mixing and before u e It is dependent on the characteri tics and bulk of th resin the alllount of hardener the degree and method of acceleration and the workshop onditions
245 Methods of application
2451 General The mixed resin may be applied by hand or b pray c1epoition The operation must b completed within the gel time of th y tern and tbe laminat fully cOI1olidated to achi v the phy ieal properties pecified
2452 Hand lay-up The duct surface i coated by hand with resin Llsing a brush and a mar of gla fibp orked in until full consolidation achieved Th proc is repeated untiJ th requird thicknes i obtained
2453 Spray depo Won The duct surface is coated WiUl re in by spray gun with the chopped glass roving added through a separate nozzle The full thickne i obtain d in layer with con olidation of each layer by hand roller
246 Construction
2461 General M ini mum COllst ructional requireshyments are pe itied ill Tabl 10 for rectangular and Table 1J for circular dUClS
2462 Joints and stiffeners Fig 29 30 31 32 amp 33 hoI TOSS
joint and tiffener for reinforced UPVC and PBPP duct
247 Worki g practices The fabrication of ductwork pecifiecl ill thi document i not affected by the addition of GRP
29
DW154 SfJcdJicatiOt for Plastics Ductwork
Table 10 Minimum constructional requirements shy
Longer Side Minimum Sheet Thicknes and
GRP Reinforcement
UPVC FBIPP 1 2 3
mm mm mm Up to 1000 3 plus 3 plus
06 kgm2 06 kgOIl GRP GRP
1001 to 2250 45 plus 3 plus 06 kgm 12 kgm
GRP GRP
2251 to 3000 45 plus 6 plus 12 kgm 12 kgm
GRP GRP
Cross Joints
UPVCFBPP 4
mm socket amp spigot
as Fig 30 or flanged as Fig 29
75 x 9 flange welded on both sides as Fig 29
75 x 9 tlange welded on both sides as Fig 29
rectangular GRP reinforced ducts
SlifTeners Maximum Spacing Between
JointsSljffeners UPVCIFBIPP UPVCFBPP
5 6 mm mm
75 x 9 flat 800 as Fig 31 or
50 x 50 x 5 plastic or MS inverted angle as Fig 32
or tormer as Fig 33
75 x 9 flat 600 as Fig 31 or
50 x 50 x 5 plastic or MS inverted angle as Fig 32
or former as Fig 33
75 x 9 flat 600+shyas Fig 31 or 50 x 50 x 5 plastic
or MS inverted angle as Fig 32
or former as Fig 33
Note 1 On rectangular duct up to 400 mm longer side no stiffeners are required 2 Applies to Tables 10 amp I I For COlJstructional operating temperature limits refer to Part 2 clause 5A 3 Tables 10 amp II apply to all pres ure classes up lo ]500 Pa
Table 11
Diameter
1 III
lJp to 1000
1001 to 1750
1751 to 2500
Minimum Sheet Thickness and
GRP Reinforcement
UPVC FBPP 2 3
mm mm 3 plus 3 plus
06 kgm 06 kgm GRP GRP
45 plus 3 plus 06 kgm2 18 kgm
GRP GRP
6 plus 6 plus 12 kglm2 18 kgm1
GRP GRP
Cross Joints
UPVCFBPP 4 III
socket amp spigot as Fig 30 or flaoged as Fig 29
75 x 9 flange welded on both sides as Fig 29
75 x 9 flange welded 00
both sides as Fi 29
inforced ducts
Maximum Spacing Between
JointsStiffeners UPVCIFBPP
6 mm 2400
800
600
Stiffencrs
UPVCFBPP 5
mm 50 x 9 flat as Fig 31
75 x 9 flat as Fig 31 or former as Fig 33 75 x 9 tlat as Fig 31 or t()rmer as Fi 33
ote On extruded tube tip to 600mm diameter no stiffenergt are required
30
DW154 Specificatioll for Plastics Ductwork
G - Cross joints and tiffeners
Fig 29 Flange Joint Fig32 Stiffener shy inverted angle
M artiPfCuQkbdd erttpObri) Wl111 RP tlddtlt
_- GRPloliu] lh~
Fig 30 Socket and spigot joint Fig33 Stiffener shy use of former
Fig 31 Stiffener Flat
I Pv FlPP ~ ~lmJaDUA1) d
OMrlQ rrnall 1( tQlS
25 STANDARD COMPONENT DRAWINGS AND ABBREVIATIONS
251 The illustrations in this section not only highlight where applicable geometric limjtations for the de ign and manufacture or ductwork components but also recommend
standard drawing representation terminology and abbreviations for both duetwork components and some of the more commonly used ancillaryplant items
252 Designers and surveyors should note that bills of quantities should provide a full description
3)
---
v
DW154 Spcc(fim(ml for Plastics Ductwork
Fig 34 Linear Thermal Expansion
u c 0 N ro 0)
b 0)
S
sect0
5 oS cl) 0)
~
on ~ ltl
c U
-30 -20 -10 0 10 20 30 40 50 60 70 80 90 TEMPRATURE C
~ V
-
~~c_ ~
~V
V ~
-7 ~
-- ~V ----
v
-6
+14
+12
+10
+8
+6
+4
+2
0
-2
--4
ig 35 Typical Design Stress tor UPVC and P
7
6
r shy 5E
-c E----0 4t) VJ 0)
ci5 0Jl 3
~
0)
Cl
2
1
o
UPVC
1
000
1
1
pp
- r-- shy r----- shy - t--shy I
__0
-30 -20 -10 0 10 20 30 40 50 60 70 80 90 TEMPERATURE C C
Note Figso 14 amp 35 shaded area refers to GRP reinforced duct
32
DW154 Speciicfltirm for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - REC ~NGULAR
Splilt~r Posilion W-mm pliucr
A B c 40]--QOO 1 W - -
601-1000 1 W4 Wf2 -
1001-1800 3 WI W3 W2
FIG DRAWING DETAfiS
tU]36 ATI Straight Duct with socket and spigol joint
rn [037 Straight Duct with flanged joints
[I []38 Straight Duct with flanged joints
rkJ Short Radius Bend
39 Applies to any augl and for duct up to 400 n11n wide
Minimum (I1m31 radills = 100 mm
Medium Radius Bend (a illustrated)
[kJ Applies to any angle
40 Long Radiu Bend Similar but radius = W
Throlll radius = W2 Applies to any angle
- Short Radius Bend with plitlers
I -shy -shy u co - t lt Li--_ 41 t 0 ~ I I I
~ I
L 1W
Minimum waal radius = 100 mm Splitters not required in bend angle less than 45deg
42 QJ1 Square Bend with turning vanes ij
3
DW154 SP(L~ficatioll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - RECTANGULAR
FIG DRAWl G DETADS
43
~
I v
L L Radius Tee with internal deflectors
44
~ Radiussed Twin Bend
45
Imiddot
er Swept Branch
46 U-
Sqoare Tee with Turning Vanes
47
~ f
Breeches Piece
48 0 y l Piece
34
DW154 Specificatioll for Plastics Ductwork
STANDARD COMPONENT RAWINGS - ECTANGULAR
55
54
51
50
53
52
49
FIG
~MX
RAWlNG
DmiddotMAX
EfjMAX
Minimum throat rndius = 100 mm
Rectangular shy Round Transformatioll
Eccentric Taper 225deg max in either plane Spliller are required for angles greater than 225deg and hould bi eet the angle between any side and duct centreline
DETATLS
Angled Offset
OUset Taper Splitters are required for angle greater than 22 0
and shoold bi eet the angl between any side and dUCI centrelinc
Mitred Offset
Concentrk Taper 2250 max in ither plane SpUtters are required for angle greater than 225deg and should bisect the angle between any side and duel c ntreline
Radiussed Offset
35
DW154 Splcilcuthm for Plastics Ductwork
STANDARD COMPONENT DRAWINGS ~ RECTANGU AR
Branch ducl DimCllsions widlh (W) (A)
urnl mm up lO 200 75
300 100 400 125 600 150
Ocr 600 200
FIG DRAWlNG DETAILS
56 poundplusmni~~ Rectan~lar - Flat Oval Transformation
57 [ Square Branch
58 er Angled Branch
Branch dUCI Dimensions wfdth (W) (A)
[- mm mm59 3shy Shoe Branch Up (0 200 75
--shy AIshy + 300 100
400 125
450 MAX 600 150
Over 600 200
Branch duct DimensIOn
rP X width (W) A)
60 - 1--shy _
~ mm mm
Bell Mouth Branch pto 200 75 300 100 t 400 125
600 150 Over 600 200
0=0 61 -
~ Bell Mouth
- shy T 4-5deg M x
--I 1-shy
TJ
62 X I ] I
Tele-scopic Joint I Illustrated with flangeL
X63
SBD Single Bladed Damper
36
---
DW154 Spedicatioll for Plastics Ductwork
STANDARD OMPONENT DRAWINGS - RECTANGULAR
DRAWING DETAILSFIG
64 on-Return DamperNRD shyshy
shyXbull
Multi-Leaf Damper Can be piggoted or flanged oppo cd or parallel blade
Alternative controls areshy
q p [gtshy
J HD65 Hand
~MD otori ed
PO Pneumalic
L-lt
l 13G 66 Blast Gate DamperX X
FireSmoke DampersSleeves
211r Ratinggtshy----
L_-
---
----
r----
Ir-- shy
IL- _-l
2hr
With i tallation frame
67 41 r Rating
4hr
Smoke damper SD
Intumc cent Sleeve L-d
37
DW154 Specijicutiolt for Plastics Ductwork
FIG
68
69
70
71
STANDARD COMPONET DRAWINGS shy REC ANGULAR
DRAVING DETAILS
gtshy Access Openings
AP 6 Access Panel - Rerno able
w [ ~ Access Door - Hinged
I ~le Inspection Cover
le -I reg -lt
~X X Flexible Connection
~ Drop Cheeked Radiussed Twin Bend
U Drop Cheek Bend
I
72 Air Flow SymbolX
38
DW154 Specifim[ioll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - ECTANGULAR
FIG DRAWING DETAILS
73
74
75
76
77
Q
Q
rp---t
~
V- I Ir---I
JL --11
THE ABOVE DETAILS TYPICAL PLENUM
Air Terminal Plenums
Plenum with side connection
Plenum with top connection
Cover plate with connection
Special plenum with connection
elescopic conn ction in direction of air flow
39
DW154 SpecijicotiOll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG
78
79
80
81
DRAWING
-23~---pound3-(MALE) (FEMAJE)
-t=j--_j(--d-shy
--L
~ THROAT RADI S= D AS T NDARD
e ~
THROAT Rjf)lU = D A MU)
DETAILS
Straight Duct With male and female connectors
Straight Duct With flange joint and slip joint
Bend MouldedIFormed Applies to any angle ego 30deg45deg60deg90deg Medium radius bend as illustrated Long radius similar but throat radius 0
Segmented Bend 90deg four section minjmum as illustrated
Other Angles 60deg = 3 sections 45deg = 3 sections 30deg = 2 sections
I
i
40 shy
DW154 Speciicafinll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG DRAWING DETAlLS
82 Segmented Twin Bend Radius = D2 max
May also be fabricated from tube
83 Equal Tee MouldedIFormed
84 -~ 1in Bend MouldedIFormed
85 Taper Concentric 1 0 as iUu trated Eccentric 30deg iJJcLuded angle
86 Short Taper
41
DW154 SpcUicatol1 for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG DRAWING DETAILS
87 30 max Offset
Angle Branch
Bran h dUCI Dimcnsions dia (D) lA)
Shoe Branch mm mm 88 Cl
Off rectanguJur Up 10 200 75 lOO 10 400 125
- 00 150 Over 600 200
Bl1IllCh duct DimenlOns din (D) (A
~-$a-Conical Branch mm mm
89 Also acceptable with Up 10 200 r
full conical surface 300 10
400 125
END VrE -shy 600 150 Over 600 200
90
m 75
100 12 150 200
mm Up to 200
_ 300 400
600 Over 600
iUtred Branch
Shoe Branch
J-L----U ~ Bell oulh Branch
ENDV1EW
93
92
91
42
DW154 Specificatiol for Plastics Ductwork
STANDARD OMPONENT DRAWINGS - CIRCULAR
FIG
94
DRAW G
I
~ 30deg 090deg
Breeches Piece
DETAILS
95 amp-----~ Blank End
~-----p Multi-Leaf Damper Can be piggolcd or fianged opposed or parallel blade
Alternative controls areshyri=-+- L-T~
I
---
LT~
I r- -
-+1
J HO Hand96
bMD Molori cd
PD Pneumatic
tl-shy bull
Single Bladed Damper 97 ~ saD
on-Return Damper Vertical application only 98 m~D
43
DW154 Sf1tcificatioll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG
99
100
101
102
DRAWING
$ I-
2hr
1 4hr
SD
~v I I
CO TINENTAL COWL
DETAILS
Iris Damper
Fi reS moke Dam persSleeves
2hr Ratillg
With installation frame
4br Rating
Smoke damper
Intumescent Sleeve
Access Openings
Access panel - removable
Access door shy hinged
fnspection cover
Discharge Continental Cowl
44
DW154 Sp(Cii(ltJll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
DRAWINGltIC DETAns
-
I
I
~
I I I High Velocity Discharge Terminal 103 I
I
I I
J I I 1 ~--
Offset Stack Discbarge Terminal 104 1
~ I e --(-
I
N
I
I
I~
I I Vertical Oischarge with Weather Cowl 105 I
--1--1 I
I
GAPI I
RTl AL DISC) lARGE WITH W ATIIER COWL
45
DW154 SpecUicatoll for Plastics Ductwork
STANDARD COMPONE T DRAWINGS - PLA TEQUIPMENTIMISCELLANEOU
FIG DRAWING DETAILS
106 ~~~ Rectangular Attenuator
107 ~- Circular Attenuator
108
~ Beod Attenuator
109 J ~(f) Heating Coil
110 J ftte Cooling Coil
III Jc[ Electric Heating Coil
112 X F
Humidifier
113 [H XX Axial Fan
114 ~fB1famp Noo-standard Ductwork Cross hntchillg (of any separate type) indicates by reference to a key any non DVil54 ductwork system
115 2llIIIIJIIIIIll Flexible Ductwork
46
DW154 SJeCUicll(iol1 for Plastics Ductwork
TABLE 12 - STANDARD ABBREVIAT ONS
ABBREVIATION FLL
AD Acces Door
AFF Axial Flow Fan
AHU Air Handling nit
All Aluminium
AP Acess Panel
AT Attenuator
AV Air enninal Unit
BE 81ank nd
BQ Blast ate Damper
CC Cooling Coil
CF Centrifugal Fan
CTA Cross alk Attenuator
CVU Constant Volume Unit
DP Drain Point
EEC Electric Heating Coil
El Expansion Joint
FAl Fresh Air Inlet
FA From Above
FB From Belo
fBPP Fabric Backed Polypropyl-ne Sheet
Flexle Flexible Connection
lexfD Flexible Du t
C False Ceiling CO an oil Unit
fD Fire Damper
FFL Finished Floor Level
FJ Flanged Joint
FOAM Rigid Polyurethane Self xtinguishing Foam
FOB Flat on Bottom
FOT Flat on Top
GAM Galvanised after ManufacttrJc
GRP Glass Reinforced Plastic
GSS Galvanised Sheet Steel
HC Heating oil
HD and controlled Damper
HH Hand Hole
HL High Level
HVD High Velocity Discharge
IC Inspection Cover
ID lri Damper
IFS Intumescent Fircleevc
47
DW154 Specification for Plastics Ductwork
TABLE 12 - STANDAR ABBREVIATION CONTINUED
ABBREVIATION
IU
L
tv1D
MS
NRD NTS
OBO
OE
PHD
PD
PP
PP
PRD
PVC
RFC
RSC
R
SBO
SO
S1 TST
SSL
TA
TB
TO TJ
TP
TV
TV
OS
UPVC
S
V
VAV
50 RSA
FULL
Induction Unit
Low Level
Motor controlled Damper
Mjld Steel
on Return Damper
at to cale
Opposed Blade Damper
Open End
Parallel Blade Damper
Pneumatic controlled Damper
Polypropylene
Self xtinguishing Polypropylene
Pressure Relief Damper
Polyvinyl Chloride
Rolled Form Chamlel
Rolled Steel Channel
R fUnit
Singl Blade Damper
Smoke Damper
Slip Joint
Stainl t el
tructural Slab Level
To Ab vc
To Blow
Top Down (In Direction of Flow)
Telescopic Joint
Test Point
TU111iog Vane
Top Up (In Direction of Flo )
Voles Otherwise Stated
Unpl3sticisecl Polyvinyl Chloride
Underside
Ultra Violet Light
Variable Air Volume
Rolled Steel Angle (Vith Size)
48
DW154 SJeriiflllioll for Plastics Ductwork
A2 DUCT PRESSUREAPPE DXA Ductwork con truct d to DWIl54 will bebullbullbullbullbullbullbullbullbullbullbullbullbullbull
Air Leakage From Ductwork To be read in conjunction with DW143 A practical guide to Ductwork Leakage Testing
CAUTION As highlighted ill both this docul1lenr and DW14 I lot ellough emphasis can be placed 01 the fact that except for high pressure class C the much more stringent ductwork constructional standard brolght about b the general acceptance of DW154 have irtlally negated the requirement for leakage-testing It is essential lO realise lhat except where it is mandatory this doclllllelll is nOl an endors ~lIlent of the rourine testing of ducts bllt purely a guide to outline the procedures for cononnity with the air leakage limits ill Table l Where the specified methods of assembly and
A3sealing of dlcls are u ed a vi ual inspection wil ordinarily sl~fll e for ver(iatioll of a well engineered and a ceptahfy airtight COl1strucrioll WHERE NOT MANDATORY DUCT LEAKAGE TESTING IS GENERALLY AN UNJUSTIFIED AND SUBSTANTIAL EXPENSE
A1 INTRODUCTION L akage from ducted air distribution systems is an Lmportant consideration in the design and operation of ventilatjon and air conditioning middotystems A ductviork t)ystem tbat ba limited air leakag within defiucd limits wiH cnsUft
that tile design characteristics of the sytem can be maintained It wilJ also ensure that energy and operatLonal cosb are maintained at optimum levels DucLwork constlucted and Ulstalled in accordance with DW154 should minimise a level of air leakage that it) appropriate to tll operating static air pre sur in tile system
A4However it is recouuised that tbe environment in wtJich middotystems are installed is not always conducive to achieving a predictable level of quality in term of system ajr leakage and it is therefore accepted that designer may sometimes require tlle ystem to be tested in part or in total It should be ecogni ed that the testing of duct systems add a ignificant cost to the installation and incur some extra tjm within the programme (Se 47 and 64 re mandatory te-sting)
manufactured to a structural standard that is compatible with the system operating pressure There are three classes of duct con truction to eorre pond with the three pre ure clas meations Class A Lo pressure ducts suita le for a maximum positive operating pressure of 500 Pascal and a maximum negative pressure of -500 Pascals Class B IVledium pressure ductmiddot suitable for a rnaxilnuJJl positive operafjn o pressure of 1000 Pascals and a maxllnum negative pre sure of -750 Pa cal Class C High pre sure ducts suitable for a maximum po ilive operating pressur of 2000 Pa cals and a maximum negativ pres ur of -750 Paltcals
LEAKAGE FROM DUCTWORK Leakao-e front pia tic air ducts occur at the joint~ and is therefore proportional to the total surface area orthe du twork in th system Tb level of leakage i imilarly related to tIle air pres ure in th du t system and whilst there LS n precis formula for calculating the level of air los it i generally accepted that leakage will increase in proportjon to pressure to rbe pOvver of 065 The effect of air leakage from high pressure velocit ductwork is critical tn terms of system perfomlan dege energy consumption and the risk of high frequency noise as ociated with leakage These problems are le critical with medium pressure 10 ity systems but should be con idered Low pres mevelocity ducts present the lowe~t
ri k in tenn of tbe effect of leakage on the operation of the s stern
SYSTEM LEAKAGE LOSS As there i no di ct relatLonship between th volume of air conv yed and the surface area f the ductwork sy tern required to match the building configuratmn it is difficult to express air leakage a a percentage of total air volume Similarly the operating pressure will vary throughollt lh 3 system and a leakage is related to pre me the calculations ar comple However it is generally ac epted tbat in typical good quaJjty systems the leakage from
49
DW154 Specificatioll for Plastics Ductwork
each class of duct llnd r operating condition will be io the region of CIa S A low pressure 6 Clas B medium pres un 3 Clas C high pressure 2
A5 SPECIFYING AIR LEAKAGE TESTING Re peeting both the co -t and programme implications a sociated with te ling du 1 for leakage the designer may for example indicate that a particular system is te ted as follow
a) High pressure ducts - all tested b) Medium pr ssure duets - 10 of the
ductwork shall be s eet d at random and tested
c) Low pre sure - unte ed In any case where a random te t i elected for medium pre sure ductmiddot the followin c1au~e is suggested for inclusion by the de ign r
The designer hall elect at random a maxirnwlI of 10 of the dUCl system to bt tested for air leakage The duct hall be tested af the pressure recommended in Table J3 for the assifi atiol for the ectiol1 of the ductwork that is to be tested The tests shall be carried Ollt as the work proceeds and prior to the application of thermal insulation In the event of test failure of the randomlY selected section the designer shall have The right to select two La1her e tiolls at random for resting Where succes ive failures are identified there shall be a Tight to require rhl COl11raCWr 10 apply remedial attention to the complete ductwork system Th contractor shall provide documented eviden e of the calculalions used to arrive (1
the allowable 10 I for the section to be tested and the client or his agent shall willess and sign the results of the test
able 13 Air leakage rates
Maximum leakage of duct work Static
prcssUft Low-pressure edium-prc-sure I Iigh-prebull me diJfercntial Class A Class B Class C
1 2 J 4 Pa Litres per second per quare metre of surface area 100 054 018 ZOO 084 028 300 110 037 400 132 044 500 153 051 600 058 019 700 064 021 800 069 023 900 075 025
1000 080 027 1100 1200 1300 1400 1500
029 030 032 033 035
1600 1700 1800 1900 2000
036 038 039 040 042
Note Recommend d mean test presures are highlighted iD bold type with the actual selection being left to tll test operator
50
DW154 Sfeeiieaioll for Plastics Ductwork
A9
A10
and air leakage classification for the y em under test
DESIGNERS CALCULATIONS The designer can middotaJculate with reasonable accuracy the predicted total loss from a ystem by
a) Calculating the operatin presure in each ection of the sy tern
b) Calculating the surface area of the ductwork in each correspondin pre lire s ction
c) Calulating the allowabl~ los at the operating pressure for each ection of the system (see table 13 for allowable leakage figures)
VARIABLE PRESSUR S IN SYSTEMS De igner can achieve significant co t saving by matchina operating pressures throughout the system to constmctional standard and appropriate air leakage testing eO the practice of specifying construction tandards for whole duct sy tems based on fan discharge pre sure may incur unnece sary costs on a project For example ome large sy terns ould well be classiC ed for I akage limits as follows
Plant room risers CJas C Main floor distriblltJou CIa B Low pre sure outlets Cla A
A6 SPECIAL CASES There may be ~itLlations on a project where circumstance dictate thal pecial consideration be given to containing air loss s eg a long mn of duclwork may incur a di -proportjonate level of air 10 s In ca es such as thi example the designer can specify an improved tandard of airtighmess ie 80 of alJo~able 10 s for la B Ju ts The designer sbould not specif a CIa C t sI at CIa s C pressure for a CIa s B ducl
A7 SUGG S ED RANGE OF TES ING
A8 TESTING OF PLANT ITEMS Items of inline pJant (eg Fig 106 to 115) will not normaUy be included in an air I akage test The dllctwork contractor may indud such itelllS in tbe te t jf rh quipm ot has a certificate of COnfOlnlity for Ihe pres ure clas
bull High pressure duct bull Medium pre sure ducts bull Low pre sur ducts bull Exposed extract syst ID bull Ceiling void extract
systems bull Secondary ducts from
VAV or fan coil units bull Flexjble duct bull Final connections and
branches to grille and diffusers
100 test See A5 Untested UDt sted
Untested
Untested Untested
Untested
SI
i
DW154 SJecijicafion for Plastics Ductwork
ig 116 Permitted leakage at various pressures
Leakage in litres per second per square metre duct surface area
Vgt
o ltgt 0 ltgt N
ltgt Cgt
0 0 cc
0 0
~
g =
g ~
c 0
J
ltgt 0 I
~ ] tn
ltgt ltgt
In ol
~ 0 ~ 8 ~
~
c ltgt ltgt
~ CJ
~ ~ ~ ~ 8
0shyij
~ ~ ~ t
ltgt ltgt 00
l
~
~ Q
c C
~ rshy
e ltgt
I 1
I Cgt ltgtv
c Co ~
~~ ~ 10
I
0 Cgt
fJshyq 410 ) 1 ltgt
ltgt N
~ shy ltgt ltgt
~ I 1
c
52
DW154 Specificatio for Plastics Ductwork
Example of a completed test sheet Test No
General
Name of job N~ jC43Pt(r2lef Building Repound ~(~~0
Part 1 - Physical details
a Section of duct work to be tested ~(diffPIfff~el1f3rd Floor
b Drawing Number g91~~ c ssure aSSJ L atlOn V~Jl~IRfYgtg~~lPre Cl T Class C
d Test static pressure -(9 raErq~ ~~~~-~~J~~~ ~~ ~~~~ll
Leakaoe factor 9~-tre3$ecMz I OM REFTOTABLE 13)e b bullbullbullbullbullbullbull
f Surface area of duct under test Q~tJJItetre$ CPROMCALCU TIO BELOW)bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull ampampamp bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull
g ]Vlaxi mum permitted leakage -~ (~i~~0 ~~r~~ ~~~l-~-11~ ~~~Q
Part 2 - Test particulars
a Duct static pressure reading 9QFt~q~ ~ middot~~~1 ~~
b Manufacturer and type of liow measuring d vice (-~~~cJ~Y-9Q7EYg c Range of measurement of now measuring device QtP)OQ~(e~~~0I~~~~1~I~ ~~~~~~W~
d Reading of flm measurin o device pmiddot IFROM RIO)ftscag ~
I (DERlVED [ROM CHART SUPPUED WITH RIG US 0 ud)1e Interpreted air flow leakage rate ~(~~~f~~~ (~l~~~~~~~~~~~~~~~~~I
f Duration ~~~~~norn~allY l~ lnil1Ut~~d~~~ it1~ W~ Date of test ~(lITled ut by Wltll s ed by ~ ~
(~lJ MIJLrr) (Si~rrfltJUYJ
Printed Name 1~g0f~ Printed Name ~~Y~9~ and Company 7jl~~~~~( UJd CompanY AB COII$Itallt8
Width and depth or diameter
Periphery ength Area
millimetreS millimetres metre qL1are metre
800 x 750 3100 1755 5440
600 x 650 2500 557 1193
300 x 300 1200 120 144
305 din 958 700 670
250 dia 785 450 353
TOTAL 8000
53
DW154 Specijilarion for Plastics Ductwork
pA XB
Guida ce No es For he ransport Handling and
Storage of uctwork
avoid damage to adjacent duct panels In somc ca es particularly on con acts calling f r repetitive sizes the use of timber jigs and spacers may be justified Where reduced bulk and greater protection are major factor such as consignments for export transporting ductwork in L shape sections may justify the increa ed ite as embly co ts
It is recommended that before a contract is finalised that consideration is given to the subject of site acces material handling and storage as tbcy havgt a strong influence on the cost efficiency of the overall activity of ductwOlk installation
B3 Handling To minilnise th risk of damage duct sections should be clearly identified and deliveries to site should be closely linked to the installation programme so as to avoid accumulation of
B1 Storage and Handling of Ra Material Material should be stored in suitably designed racking out of direct unJight Where possible the e racks should be metal to earth Edges of cut she t may be harp and protective gloves are advised Wearing teel toe-capped boots is recommended Most pIa tic sheet is manufactured with smootb mfaces andor is suppLied with protective coating Care must be taken to prevent accidental lippag of stacked materials Beiuoshy good electrical insulators the movement of stock unless earthed will allow the build up of stati All stock shapes are chemically stable at normal temperature Whil t some raw materials used in their manufacture may themselves pre ent a toxic hazard once incorporated into the lOck bape they no long r constitute such a hazard and no dermatitic bazard are known nor are any
unfiJied ductwork and minimise double handling It is important to recognise that ductwork panels joint and corners arc susceptible to damage and care must be taken wheu band ling such material through a site During handling individual item of duct work may be liable to light cross sectional deformation until thev become an integral pan of a completed ductwork system Whilst this may temporarily detract from its intended appearance thi deformation will not have any detrimental effect on the functionality of the finally a semblecl system Installation of duct work and asociated plant items ill illevitably involve manual handUng The responsibi Iiry of employers and employees to a ses the risk of personal injury during mallual handling operations is et out in the HS E publication L23 Guidance on Manual Handling Regulations 1992
environmental problems expected 84 Site storage
B2 fransport Large capacity vehicles with high-sided open or closed-top bodies are tlle mo t suitable for the transport of dllctwork Careful consideration should be given to the
Adequate floor space IDust be provided within tbe building for the site storage of ductvork Such storage shalt make due allowance for thc stOf(ne of ductwork in stacks such that access ~ egt
between them is of sufficient width to pennil the removal of item without interference to
unloading of transport on sit a not all siJes b n fit from the material handlino- and access facilities that exi [ in a manufacturing workshop such as crane- fork-lifts or loading bay Site handJiog facilities along with
adjoining sta ks Ductvork components should be positioned so a to avoid crushing Ductwork of small panel size may be stored horizontally however care should be exercised to ensure that tack sizes are limited 10 within
ehicular acce s restrictions may itilluence the type and ize of transport to be uWised
engtlls of ductwork should be positioned 0
the tmctural strength of the duct sections to prevent distortion of the lower sections within the stack
as to avoid crushing Lengths Witll projections such as branches and bends i1anges girths damper quadrauL should be loaded so as to
54
DW154 S1tciic(ltioll for Plastics Ductwork
85 Internal cleanliness of new ductwork The site storage of ductwork introduces the important cODsideration of maintaining the internal cleanliness of the ductwork R feren e should be made to HVCA documentshybull DWffM2 Guide to Good Practice - internal
Cleanliness of New Ductwork Installations If the above conditioDs can not be satisfied consideration should be given by tJle designer to amending the specification to include for Po t Installation Cleaning as covered by tJ1C HVCA documentshybull TRJ17 Guide to Good Practic - Cleanliness
of Ventilation Systems
APPE DIXC
Fi e Retardant inishes C1 Improvement in the fire retardancy of plastic
ducts can be achieved to varying degrees and is wholly dependent llPOll the surface coating laminating resin selected and construction specification adopted In some instances smoke emission is coILSidered equaUy with other speci fication requirernen ts of the materials resistance to ignition and bumjng It is therefore important for design rs to establ ish the clients and officers detailed requirements and not rely on a tbird party interpretation of fire resisting or fire retardant Where possible the specification should refer dir etly to compliance with a British or European Standard identifying the specific sections applicable There are various types of resin and mat rcLnforcements that can achieve a Class 1 surface spread of flame ratin o when tested according to BS476 Part 7 (1987) This test puts materials illto Class I - 4 in descending order of perfoDllance according to the rat and extent of flame spread over their surfac under standard beating conditions Materials should also be tested for flre propagarion to BS476 Part 6 (1989) Tbi tesr measures the amount and rate of heat evolved by the material when subjected to standard heating
conditions Test results are given as an index of Perfonnance (i) whicb is based on three sub indices (iJ (i1) (h) The higher the value of the Index of Performance (i) the greater is the material s contribution to fire growth The higher the value of the sub-index 0) rhe greater the ease of ignition aod flame spread The highest product performance classification as defined in Approved Document B of the Building Regulations is Class O This is acLlieved if a material surface of a composite ploduct i~ either a) composed throughout of materials of
limited combustibility or b) a Class I material which has a tlre
propagation index (i) of not more than 12 and sub-index (i l ) of nor more than 6
01 J Class 0 is not a cla$sif1cation identified in any British Standard test
There are resin system reported to be classified to Class O when tested to BS476 Pcl1S 6 and 7 however designers need to ensure that such sysrems can be applied to their proposed design In propriety resinmat system available the fabrication techniques and COITect application are critical to the integrity of the reinforcing and clas ificatiol1 For example in some systems the u e of a non-fire retardant gelcont on a fire retardant substrate would reduce the classification For further information see HVCA publication DW144 Appendix D
55
DW154 SplCijiClIliol1 for Plastics Ductwork
x Guidance otes For nspectmiddoton Servicing a d
Clean-ng Access Openings
D1 GE ERAL This appendix highlight in ummary fOI111
the acce considerations that hould be made by the design r iD terms of inspection servicing and cleaning Having considered the seop and the design of the dUCI work system relative to the guidelines outlined below the designer should clearly indicate which levels of acces should be incorporated into the manufacture of a new duct work system (See Table 14 and Note I b low it
D2 DESIGN CONSIDERATIONS
D21 In ptction and servicing requireshyments are set out in Section 15 of Lhis specification
D22 Cleaning requirements are set out in the HVCA pubUcation TRl7 Guide to Good Practice Clean Lines of Ventilation Systems and the guide tates The precise location ize and
type of access would be dependent on the type of ductwork cleaning inspection and te ting metbods to b adopted Care protection and standards of cleanliness prior LO cOlllmisionin o
are set out in th AV A publication DWITM2 Guide to Good Practice Internal Cleanliness of New Ductwork Installations and th guide state Wh re specific limits of cleanliness are required ductwork sball be cleaned after installation by a spcialist cleaning contractor It will b in the interests of tht desioner botb financially and practically to cunsider employing a specialist c1eauing contractor at tbe
outset of a contract to internally clean newly installed ductwork prior to bandover This approach would reali e the following benefit shyi) Tb actual numb r of cleaning
access panels could be detennined to suit the method of cleaning to be adopted (This may be 1 s than the maximum requiremen listed under Lev 13 of Table 14)
ii) Clear directions could b given to the ductwork contractor as to tJle size and location of cleaning access panels that are required to be fitted during the mauushyfaclunng pro s
iii) The specialist cleaning operation prior to commi ioning vould enable the cleaning contractor to verify the practical acee requirement for the future cleaning operation associated -vitb a regular maintenance programme
iv) A specialist cleaning operation prior to commissioning would allow the designer to omit from the speeilicatiolJ the DWrrM2 requirem nt for factory sealing protection wipe downs and capping-off
v) Specialist Ieall ill 0 to the measurable standard defin d in TR17 will allow an objective definition of cleanline to be achieved
Car ful consideration must be gIven by the designer to the practl aJ problems associated witb the manufacture and fitting of suitably si Led access panel on small cross section duct and on the circular faces of rouod and flat oval ducts in particular
D23 Special con ideration must be given by the de igner to the practical problems associated with gaining personnel access to heavily congested ceiling areas and multi-la red du twork systems This approach would avoid
56
DW154 Spfciication for Plastics Ductwork
the possibility of access panels being D3 ACCESS 0 IN-LINE EQUIPMENT incorporated into a ductwork system at the This appendix unly covers acc il1spection manufacturing stage that were later found in through the ductwork body adjacent to an item practice to be inaccessible for either ervicing of in-line equipment and not openings in the or cleaning activities equipment itself
able 14 Acce requirements for inspection servicing and cleaning
HVCA PUBLICATIO REFE NeE (uidtgt 10 Gund Prartict
Adjace t OW144 Cleanliness orVcnlillltio S~lcr~ fRjJ7
in-line LeyeJ 1 Level 2 Level 3 ite sequipment pcdionSen lcin~ Section d C1eaniJl( SUn(O)lnspc lion Palle ltk~m_n
2011 (minimum OiL Jubje-ct to duct ~zel (ft~ -Panels
Control Da pcrs One (inspection) 203 One 300 mm x 200 mm Both sid Fire Dampers One (sCTjdJl~) 20211 One 300 0101 x 200 mm One side HeatingCooling Coils One (inspedion) 20213 One 300 mm x 200 mm (lIpstream) Both sides Attenuators (rectangular) None required One 300 mm x 200 mm (downstream) Both sides Attenuators (circular) one retluired One 300 mm x 200 mm (downstream) One side Filter Sections One (inspection) 20212 one required Uoth sides Air Turn Vanes None requjred None required Both sides Changes of Direction None required one required One side In-Duct FansDevices One (inspection) 20213 None required Both sides l
1 In the absence of any indication by the designer only Level ) access will be jncorporated into a new ductwork system
2 Tbe panel izes associated with Lev lis I and 3 acee s ar e middottablished by reference to Section 20 of DW144 and Section 2 ofTRll7 respectively
57
DW154 Speclfifatio for Plastics Ductwork
pA XE
B-bliography Included in this Bibliography are technical pUblications which may be of interest (0 ductwork designers fabricators and erectors and to tho e in the heating ventilatlng air conditioning industries generally nquiric should be made of the relevant organisation at the address quoted Since its publication other addresse contained within 0V154 mav have changed and some pubJicalions may have been superseded
HEATING AND VENTILATING CONTRACTORS ASSOCIATION
4 Palace Court London W2 4JG Telephone 020-7229 2488 Fax 020-7727 9268
Orders fo FlY A Publications Old Matlsion House Eamont Bridge Penrith Cumbria CA 10 2BX (Telephone 01768 864771 Fax 01768 86718) Email hvcapoblicationshvwelfarecouk DWn 44 pe ilicatiun for sheet mctal duclwork (Iow- mediulllshy
and high-pressure) 1998) DWIl4 A practical guide to dUGI ork I akage te ting
(revised 2000) DWII54 Specification for plastic~ duct rk DW171 Guide to good Practice for kitchen venlibtion system DW191 Guide to good pracuce glass fibre ductwoJk DwrrMI Acceptance cheme for new products - Redangolar cro
joint classification Guide to good pra tice - Internal cleanliness of new ductwork installations Guide to good practice for the design for the Installation of lire and smoke uampers
J 1Other puhlications
HampV safely guide 5th edition JS2 Tool box talks JS5 Weldlng Safety booklet JSI9 afety facts bo klet Fact sheets 1-24 2nd edition JS2J COSHH manual volume 1 Advice on compliance with the
regulations 1521A CO I-rH manual volume 2 Asses mcnt h ets JS23 Ri k management manual TR3 BrazinltT and bronze welding of copper pipework cUld sheet
(I 976) TR5 Welding of carbon steel pipework (1980)
TR6 Guide to Good Practice for Site Pre sure Testing of Pipework (19 0) Guide to good practice cleanliness of ventilation Ylem
CHARTERED IN TITUTlO OF BUILDING SERVICES E G EERS Delta House 222 Balham High Road London SW12 9BS rTelephone 020-8675 5211 Fax 020-8675 5449) CIBSE Guide Volume A Design Data Volume B In tallatiol1 and quipment Data Volume C Reference Data
CommlssioniJIg Codes These Codes eover the preliminary checkS eUing to work and regulation of vanous catcgories 0 plan The Codes give a guide to design implications Series A Air Distnbution Systems Series B Boiler Plant
ri s C Automatic Conlrol ystems Cr1es R Refrigerating Sy terns
Sene iN Water Distribution Systems
Technkal Memonllda TM 4 Design Notes for the Middle East TM bull Design otes for Ductwork TM 13 Minimi iog lhc Risk of egiounaires Disease
Research Reports RROI95 Ventilation system hygiene - A review of published
infomlatioo on lhe occurrence and ffects of Olltamination Rl~02J95 Air-to-air heal rec v ry RR0395 rnfluen e of HV C on smoke detectors
ATlONAL ENI [ERING SPECIFICATION LfMITED Southgatc hamber 3739 Southgate Street Winchester S023 9EH (Telephone 01962 842058 Fax 01962 R(8982) BUfLDING S RVICES RESEARCH AND [ ORMATION ASSOCIATIO Old Bracknell Lane West Bracknell Berkshire RG 12 4AH (Telephone Brackl1eU (01344) 426511 Fax 01344 487 -7 )
Application Guides AGln4 De tglJing Vana~le Volume middotylans for KOOnl
iir Movement AG1I91 Commissioning of V Sylcms in Buildings 11 6194 Fire Dampers
B) 94 cntiJalion or KitcneTls
AG389 The Commls ionin of Air Systems In Buildmgs AH2192 Commissioning of Bern - A ~ode of Practice TN2417 I Fire Dampec il) Ventilating Ducl
BEATING VENTILATING A AIR CONDITION G MA UFACTURERS ASSOCIATIO (HEVAC) HEVAC Henley Road Medmenham Marlow Buck SU 2ER (Telephone 01491 578674 ox 01491 575024 Emoimiddot infofetacouk)
Publicatjons Air Diffusion Guide Guide to Air Handling Unit Leakage Testing Guide to Good Practice Air Handling Unit Real Room Acoustic ~ st Procedure Specification for the ertiiicatioll ofAir Filters Method of Test for Water Rejection PerfOnTlatce of Louvrcs Subjected 1(1
Simulated Rainfall Test Procedure for Acoustic Loo cs Specification 10 Floor GrilJes - Types Performan e and Method ofTest Specification for the Determination of the Collection Efficiency of SilJ1d
Trap Louvre Domestic Mechwlical Vclltllalion Systems with Heal Recovery Fan Application Guid
~an and Ouctwork Installation Guide Guide to Fan Noise and Vibration
pecification of Requirements for JallJral Smoke and Heal Exhausl Ventilators
pecification for Powered Smoke and Heat Exhaust Ventilators
Specification of Requirements for Smoke Curtains Design Gujue of Smoke Ventilation for Single Storey Lodustrilll Building~
Including those with Mezzanine Floor and IIi Racked Storage Warehou es - Issue 3
Guidance for the Design of Smoke entilation YSlem for Covered and Undergrollnd Car Parks - lssue 1
Application of SOloke Control Equipment and Syst m Guid to Good Practice - Isue J
58
DW154 Sp(C~tiifitiol for Plastics Ductwork
BRITISH STANDARDS INSTIT TION Sales Department 101 P ntooviLle Road London NI 9ND (felephone 020-78 1 78801)
CP 413 1973 Ducts for building ervices
SS 476 Fire tes on building matenals and lruc(ure
Part 4 19 4 Non-combustibility lest or materials
Part 6 I Fire propagation lest for materials
Part 7 1993 Surface spread of tlarnJ tesls for materia
Part 20 1987 Fir resistance of elements of construction
Part 21 1987 Fire r sistlUlce of loadbeanng elements of construction
Part 22 1987 Fhe istallceofllon-loadbearing elemcllts ofconsttuclion Part 23 1987 Contribution of componcnts to the fire resistance 0 a
structure
Part 24t987 Fire resi lance of wl1lilation ductl
SS 5588 nan 919 0 Fire Precautions III thc desIgn and OOSlnJ lion of buildings
S 729 1971 Hot dip galvanized oatiugs (or irOIl aod stcel articles
BS 1449 Steel plate sheet and Irip
Pan 11991 Carbon steel plate heel and strip Part 2 1983 Stainless steel plate sheer and strip
and
B middotENJOI49-2 996 BSEN 10149- 1991)
BSEN 10131 1992
BSEN22063 Sprayed metal coarings 1994 Protection of iron and steel by aluminium and zinc against
atmospheric cOlosion Irotectiotl of iron and ste I against corro ion and oxishydation at elevared temperatures
BS 353 1981 Glossary of lerms relnting to thermal insulation
BS ISO 1479 Self-tapplngscrewsandmetallicdri c crew
B -lSO 7049
1994
B 4800 1989 Painl colour for building purposes B 4848 l0 rolled structural steel sections
Part4 1972 Equal and unequal angles BS 5422 1990 Specification for the use of therm illuating matcriulS
SS 5720 1979 ode of practice for mechanical veutilating and air C 11shy
dirionin bull in building
l3S PR 12814-1 Bend resting for plasric welds
SS PR 12814-2 Tensile testing for plastic welds
SS PR 13067 Appro altesting for plastic welds
BS PR EN I 100-] Vi ual in pection ofplaslic welds
SHEET METAL AND AIR CONDITIONING CONTR-CTORS NATIONAL ASSOCIATION INC (SMACNA) Headquarters 420 I Lafayeue Center Drive Chanlilly Virginia 2051-1209
Mailing Address pa Box 221230 Cbantilly Virginilt120 153-1230
Telephone (703) 803-2980 Fax (703) 803-3732
Accepted IJJdustry Pl3Gtice for Industrial Duct Constnlelion 197 ) i-rchitecmral Sheet kwl Manual ([993)
Comractors Guide lor Modification 10 ooslruerion Colllraets 1993 Ducted Eleclric Heat Guide for ir Handling Ssrerns (1994)
En~rgy ollservatioD Guidelines (1984) Energy Recovery Equipment yslClllS (199l
Fibrou GIns Duct onS1ntClion Standards (1992)
Fire Smoke amp Radiation Damper In tall Guide for HVA Syst ms (1992) Guide t leel Stack 1(95)
HVA Air Duct Leakage Test Manual (19 ) HVA COlllmissioning lvlanual (1994)
H A Duct Construction Standards-Metal amp Flexible (1995) Addendum 01 (Nov 1997)
HVA Duct Systems Inspection Guide (1989)
HVA ySlems-Application (1986) nVAC ByternS-DLlct D ign (1990)
HVi Systems-Testing Adjusting amp Balancing (1993)
indoor Air Quality Manual (1993) tcheu quipment Fabrication Guidelmes (1990)
Managers Guide for elding (1993)
Rectangular Industrial Duct Cons1TUction Standards (19 0) Round Industrial Duct oustmction Standards (1977)
Sei mic Restraint Manual (1991) (wl Appendix E 1993) SMACNA Ma le Index ()fTechnical Publications (1995) Tbennoplnstic Duct CPY ) Construction Manual 1994)
DEPARTME OF THE ENVIRO MENT (Publications Centre) H Stationery Oflice 5 Nine Elms Lane London SWS 5DR
MampEJ 011972 Electrical in tallat1011 in buildings ( ew Editiou)
IampE 0319 Healing hot and cold wat r steam and gas losla1lations for buildings
M amp - No4 1970 Central heating and hot and cold ~ ateT in tallations for
dwelling
M amp ENo100 1971 Mechanical ventilation for building~
ASSOCIATION FOR SPECIALIST FIRE PROTECTlO As ociation House 235 Ash Road AJdershot Hampshire GUl2 4DD
Telephone OJ25221322 Fax 0 J252 333901
lublicalioos Fire Ratcd and moke Outlet Ducrwork An Industry Guide t Design and InSlalla lioll
HEALTH AND SAFETY EXEC TIVE Rose Court 2 Southwark Bridge London SEl 9HS Telephone 020-7717 6000
TWJ THE WELD G TlTUTE Abington Hall Abington Cambridge CB16AL Telepbone 0 J223 89162
Publication DatJ Oil w~ldll1g of lhermopla lics
59
DW154 wciiwlioll for Plastics Ductwork
A -=--DIX
Factors
Specific gravity shy pp = 091 approx UPVC = 14 approx
Some miscellaneous conversion factors
To convert
Length Inches to millimetres Feet to metres
Multiply by
2540 03048
To convert
Millimetres to inches Metres to feet
vIultiply by
003937 3281
Area Square inches to square millimetres 6452 Square millimetres to square inches 000155 Square feet to square metres 00929 Square metres to square feet 10764
Volume Cubic feet to cubic metres Cubic feet to litres Gallons (UK) to litres
002832 2831 4546
Cubic metres to cubic feet Litres to cubic feet Litres to gallons (UK)
35315 00353
022
Mass Ounces to grams Pounds to kiJograms Tons to tonnes
2835 04536
1016
Grams to ounces Kilograms to pounds Tonnes to tons
003527 2205
09842
Volume flow Cubic feet per minute to cubic Cubic metres per second to cubic
metres per second 0000472 feet per minute 2119 Cubic feet per mIDute to litres Litres per second to cubic feet
per second 04719 per minute 2119
Motion Feet per minute to metres per second 000508 Metres per second to feet per minute 197
Pressure Inches water gauge to millibars 2491 Inches wateJ- gauge to pascals (Pa) 2491 I Pa = I ewton per square metre = 10-2 millibars
60
Heating and Ventilating Contractors Association Esca House 34 Palace Court London W2 4JG
Tel 020 7313 4900
e-mail contact Itvcaorguk web site wwwhvcaorguk
Fax 020 7727 9268
6 6
DW154 Specificathm for Plastics Ductwork
s Page
Foreword 3
co PART ONE - TECHNICAL INFORMATION TO BE PROVIDED BY THE DESIGNER Introduction
2 Standards 3 Components 6 4 Particular requirements 6
PART TWO - STANDARDS 5 Application 8 6 Ductwork classification and Air leakage 8 7 Materials 9 8 Ductwork construction and Joint sealing 9
PART THREE - RECTANGULAR DUCTS 9 Rectangular duct sizes 11 10 Construction 11
101 General 11 102 Longitudinal seams 11 103 Sheet jointing seams 11 104 Socket and spigot joints 11 105 Flanged joints 11 106 Expansion joints 12 107 Stiffeners 12
11 Fittings 12 111 Standardisation of fit1ings 12 11 2 Stiffeners 12 113 Split1ers 12 114 Turning vanes 12 115 Branches 12 116 Change shapes 12 PART FOUR - CIRCULAR DUCTS
12 Standard sizes 16 13 Construction 16
131 General 16 132 Sheet jointing seams 16 133 Socket and spigot joints 16 134 Flanged joInts 16 135 Stiffeners 17 136 Expansion Joints 17
14 PART FIVE - HANGERS AND SUPPORTS General 19
15 PART SIX - GENERAL Access I Inspection openings 22
16 Regulating dampers 22 17 Fire dampers and Intumescent sleeves 24 18 Flexible I Expansion joint connections 24 19 Protective finishes 27 20 Connections to bUilding openings 27 21 Discharge Exhaust terminal 27 22 Thermal insulation 28 23 Fire retardant finishes on plastic ductwork 24 Reinforcement of ducts with GRP laminate 25 Standard component drawings and abbreviations
4
~I-------~- --shy
28 28 31
bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull
DW154 SpaiicatiOll for Plastics Ductwork
PART SEVENmiddot APPENDICESmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotAppemiddotndixmiddotmiddotjmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotAmiddotjrieakagefroniductwork middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot49middotmiddotmiddotmiddotmiddotmiddot Appendix 8 Guidance notes for the Transport Handling and Storage of ductwork 54 Appendix C Fire retardant finishes 55 Appendix D Guidance notes for Inspection Servicing and Cleaning access
openings 56 Appendix E Bibliography 58 Appendix F Conversion tables 60
Table LIST OF TABLES _ PART TWO - STANDARDS
1 8Ductwork classification and Air leakage limits PARTTHREE - RECTANGULAR DUCTS
2 Minimum constructional requirements - Rectangular Un-reinforced UPVC and pp 13 3 Fastening centres Rectangular duct flange joints 13
PART FOUR - CIRCULAR DUCTS 4 Standard sizes 16 5 Fastening centres Circular duct Flange joints 17 6 Minimum constructional requirements shy Circular Un-reinforced UPVC 18 7 Minimum constructional requirements - Circular Un-reinforced PPS and PP 18
PART FIVE - HANGERS AND SUPPORTS 8 Hangers and Supports - Rectangular Horizontal Ducts 19 9 Hangers and Supports - Circular Horizontal Ducts 19
PART SIX - GENERAL 10 Minimum constructional reguirements - Rectangular GRP Reinforced ducts 30 11 Minimum constructional requirements - CirCUlar GRP Reinforced ducts 30 12 Standard Abbreviations 47
PART SEVEN - APPENDICES 13 Air leakage rates 50 14 Access requirements for inspection servicing and cleaning 57
LIST OF ILLUSTRATIONS 0 bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull u
Fig PART THREE - RECTANGULAR DUCTS 1-4 Cross joints 14 5-6 Stiffeners 14 7 Tie rod assembly 14 8 Hard and Easy bends 14 9 Turning vanes 15
PART FOUR - CIRCULAR DUCTS 10-12 Cross joints 17 13 Stiffeners 17
PART FIVE - HANGERS AND SUPPORTS 14-16 Support bearers 20 17-18 Vertical ducts supports 20 19-22 Arrangement of bearers and hangers 21
PART srx - GENERAL 23-25 Expansion joints 25 26-28 Flexible connections 26 29-33 GRP reinforced - Cross joints and Stiffeners 31 34 35
Linear Thermal Expansion 34 35
36-77 Typical Design Stress Standard component drawings - Rectangular 33
78-105 Standard component drawings - Circular 40 106-115 Standard component drawings - PlantEquipmentMiscellaneous 46
PART SEVEN - APPENDICES 116 Permitted leakage at various pressures 52
Example of a completed test sheet 53
5
DW154 Specijimrol1 for Plastics Ductwork
ART 1 4
bullbullbullbullbullbullbullbullbull 41
Technical information to be provided by the desmiddotg er to the plastics ductwork cont actor 42
1 INTRODUCTION 11 Thi specificalion relates to the manufa ture
and installation of rectangular and circular 43 ductwork constructed from plastics The selection of construction method is at the discretion of the manufacturer to conform with the performance requirements of the pecified 44 ductwork clas ification Sections 2-4 blow define the information to be provided by the designer
45 2 STANDARDS
21 Pressure classification (Table 1)
22 Leakage classification (Table 1) 46
23 Positive and Negative pressures (Table I)
24 Materials (Parr 2 Section 7)
25 Any special ystem requirements 47
3 COMPONENTS
31 Access and drainage points Number and location of access doors and drainage points
32 Regulating dampers Specification location and mode of opelatioll of all regulating dampers 48
33 Fire stops Stops to meet the requiremen ts of the Authority directly responsible for fire protection 49
34 Flexible joint connections Sp cification and location of any flexible conne tions eg plant or building expansion joint
PARTICULAR REQU REMENTS
Plastics material Type of plastic material from which the ductwork i to be manufactured and detail of ductwork to special requirements not within this specification
Environmental Env ironmental conditi ons inside and sULToundillg tJle ductwork
Airflow Design airflow volume for all mam ducts branches and air tenninals
Pressurevelocities Design air velocities and pressures for all main ducts principal branches and tenninals
External thermalacoustic insolation he extent and type of insulation to be
provided by others should be stated including full specification for application and installation
Spark testing U spark testing is required the designer shall identify land mark in the contract programme for testing to be undertaken ie manufactur installation corrunissionjng
Air leakage testing The extent of any air leakage testing if required While it shall be mandatory for highshypres ure ductwork (a defined in this specification) to be tested for air leakage iu accordance with the procedure set out in DWI43 A Practical Guide to Ductwork Leakage Testin2 no such te tin of Jaw-oro
mediam-pres Llr duct work is requjJmiddoted
Identification Details of colour coding or identification if required For furth r information see HVCA publication DWl44 Appendix B
Solvent~fomes
Details of design criteria used or adopted to avoid the trapping and discharge of liquid solvent fumes or gases
6
~--
DW154 Specificatio1l for Plastics Ductwork
410 Protective finishes (Part 6 Section J9) Detai Is and specification of any protective finishes
411 Fire retardant finishes (Part 6 Section 23) The extent and limits of protection for any fire retardant finishes on plastic ductwork (Specific references must be defined)
412 Controlssensing equipment Details of positions and fixing configuration of all sensors and test points to suit specialist contml and sensing equipment
413 Special supports (Part 5 Section 14) Details of any spanning primary secondary steelwork or special support requirements not specifically covered by Section 14
414 Attachment to building structure (Part 6 Section 20) Specific requirements for the junction of ductwork and associated components to opening hou1d be detailed and specified with the limits of responsibility defined
Tbe design and provision of penetrations and associated framings are outside the scope of this specification
415 Ductwork layout drawing Details of any special requirement$ relating to CAD scales etc It is common practice and cost effective for duclwork manufacturers to utilise their approved ductwork layout drawings as a basis of their manufacturing installation information by adding the necessary details to the same drawin2 Scales of 150 or smaller may preclude tJlis practice therefore larger scales might be more appropriate The final choice of manufacturing installation scales shall be left to the ductwork contractor
416 Other requirements Details of any requirements far the ductwork not in accordance with the provisions of tbis specification including any modified construction required to conform with any requirements cancerning external ductwork (See 53) or to meet the regulations of a local autbority or athcr controlling body
4 7
Clause
Reference to designer In consideration of the foregoing reference is also made to the designer in the following c1ausesshy
Page 52 8 53 8 106 12 1072 12 111 12 131 16 1352 17 136 17 141 19 144 19 145 19 147 20 152 22 161 22 1631 23 1634 23 171 24 173 24 174 24 181 24 182 27 191 27 211 27 222 28 223 2R 231 28 252 31 Appendix A 49 Appendix B 54 Appendix C 55 Appendix D 56
7
DW154 Spaijicllliflll for Plastics Ductwork
PAR 2 54
Standards
5 APPLICATION
51 This specification sets out minimum requirem nts for tbe manufaclure and in-tallation of ductwork for commercial and industrial fume extraction and exhaust 5y terns made from any of th material listed in Seclion 7 and being within the limit of ize andor material Ihickness speci led in Ihe relevant tables Normal ambient operating temperatures are assumed within the pressurevelocil limits and the limits of air leakage for the various pressur classes prescribed in Table 1
52 Thi specill alion is inlended to apply to ductwork handling fume-laden air which are polluted or is otherwise exceptional in respect of temperarure or humidity (including aturated air) for dllctwork wber the external
surface are exposed to a hostile environment The design construction installati n supports and finishes in such case should be giv n special consideration b the de igner in relation to tbe parti [lIar requir ments of each application
6
61
53 TIlis specification is sllitabl for ductwork expo ed to external atffio phere The designer will need to ~ive sp cift details of any special finish constlUction (See eetiar J9)
62
This specification i ba ed on duct operating environments of not less than - 100e and for
PVC (non GRP reinforced) nor exceeding 40degC UPVC reinforced wilh GRP not exceedin cr
600 e PPS and PP not exceeding 60deg FBPP reinforced witb GRP not exceeding 70degC Systems required to operate at temperatur outside those d tailed above aJthough outside of Ih scop of Ll)is specification are Dot precluded but the ductwork hould be designed from fi rst principle Ilaving regard for the physical mechanical and chemical properties of the material It mu~t be noted that the cOlTosive re i tance of all the above m terials will decrea e at temperatures approaching 5deg to looe below the parent materiaL beat distonion point Further guidance on temperatup effect is provided in Fig 34 Linear Tbennal
xpansion and Fig 35 Typical 0 ign Stres es for VC and PP
DUCTWORK CLASSIFICATION AND A R LEAKAGE
Classification and air leakage limits Duc work la sification and air leakage limitmiddot are eL out in Table 1
Compatibility with CEN The leakage fa tor u ed in able 1 for Classes A Band C ~u-e the ame as those for the cIa e similarly de ignated in th E Document Pr E 12237Pr L507
Table bullbull uctwork Class icati nand ir Leakage Limits (Reproduced from DWI144j
Ducl pressure class
1
Low-pressure -Medium-pressure -High-pressure
-I
I Class A Class B
Class C
Static pr sure limil Air I akage LimitMaximum air
litres per ltccnno per quarevelocity
Positive Negalive metre of duct surface areu
2 4 5 ~ -Pa Pa
f-m1s
0027 X pors500 10500 --1000 0009 x po6~750 20
0003 x pO652000 750 40
Where p is he differential pressure in pascals
Nole Tllls specification DWl54 onJy covers construction up to 1500 Pa
8
- - shy -~----
- shy
DW154 SpeciiCfllioll for Plastics Ductwork
63 Leakage at various pressures and other 110 mm to 600 mm dia (Dimensional rela tionships tolerances to DIN 8062) Applying the limits specified In Table 1 Appendix A (Table 13) sets out the permitted 74 PPS (Forms aailable) leakage at each of a serie of pressures up tu a maximum for each class Incloded in that 741 Extmded sheet in thickness 3 mm to Appendix is a graphical presentation of the 12 mm (Dimensional tolerance to pre urelleakage relationship DIN 53479)
DWl143 A Practical Guide to Ductwork 742 V series tube in sizes 1] 0 mrn lO 630 Leakage Testing provides detai Is of the basis mm dia and fittings in size I 10 mm for the leakage limits specified in Table 1 to 400 mm dia (Dimenional
tolerances DIN 53479) 64 Air leakage testing
Air Jeakage testing of low and medium 743 All PPS material used hall be pressure ductwork is not mandatory under compatible and comply with DIN tJlis specification Air kakage testing of high 4102 part B and SS 476 part 7 class pressure ductvork t mandatory under this 4 PPS material should not be used for specification and for details of testing external applications vithout suitable procedure refer LO DW143 A Practical Guide protection (See Part 6 section 19) to Ductwork Leakage Testing
744 It should be noted thal PP is not fully 7 MATERIALS compatible wilh PPS
71 Application 75 FBPP (Forms aailable) This specification applies to ductwork constructed from materials as defined below 7 51 Sheet in thickness 3 mm to 9 mm or equal Minimum material thickness is to be taken a a nominal thickness as Tables 267 7 52 Continuous roll form in thickness 2 10 amp 11 AJJ UPVC materials ued shall be mm to 4 mm low flammability selfextinguishing compatible and UV stable with pigment colour to RAL 7 53 This particular material is specifically 7011 and DIN 4802 B 1 designed to be externally reinforced
with GRP (See Section 24) 72 Types
The materials covered by thi specification are 76 UPVCGRP abbreviated herein as foIlowsshy This is a form of composite lamjnate used (UPVC) Unplasticised polyvinyl chloride where improved mechanical trengtb UV (PPS) Self eXlioguihing polypropylene stabilisatiolJ or fire retardence is required (PP) Polypropylene (GRP) Gla s reinforced plastic 77 UPVCIFOAMJGRP (FOAM) Rigid polyurethane self FBPPFOAMfGRP
extinguiShing foam This is a form of composite laminate used (FBPP) Fabric backed polypropylene sheet where insulation andor support is required for
special applications 73 UPVC (Forms available)
8 DUCTWORK CONSTRUCTION 731 Extruded sheet in thickness 3 mm to AND JOINT SEALING
12 mm (Dimensional tolerances to DIN 7748) 81 Ductwork construction
The election of longitudillal cross joint and 732 V series tube in sizes 110 mm to stiffener types within the criteria laid dOT1 in
1AOO mm dia and fittings in siz~ Part 3 amp 4 shall be used as a minimum standard
9
DW154 Spet((icatioll for Plastics Ductwork
82 Joint sealing and sealants 8226 The joint mu t be held in po ition ror at leamiddott 5
821 General minutes A jig should be The integrity of the ductwork used jf nece-ltsary to ensure depends on the successful applicatioll that no twisting force i of tbe conemiddot t jointing metbod appl ied to th joint during
the period 822 Solvent cementing
Solvent cementing a atisfactory 8227 Once made the joint method of jointing circular UPVC should not be exposed to socket anu spigot or leeve joints a undue force for eight certain solvent based cement horn shy hour Tb full strength of geneously bond the PVC surface the jOjJlt is not achieved in providing uitabl joints Solvent less than twenty-four cementing i not practicable with PP hours because of its hioh resi tanc to solvents The procedure recommended OTE SOLVENT CEMENT JOINTING by the cement manufacnJrer should METHODS ARE TOT RECOMshybe followed but the following points ME DED FOR RECTANGULAR are important DUCT SECTIONS
[N ALL CASES S ALA MATshy8221 Clearance between ocket ERlALS MUST BE APPLIED
and spigot must be STRICTLY IN ACCORDA CE minimal because of the WITH THE MANUFACTUR ~RS
lirnited gap filling propshy 11 STRUCTIO SAD OSHH ertie of the cement ASSESSMENT
8222 Inside edges of sockets and 823 Hot air welding utside edge of spigot VC and pp a be welded by
shouJd be lightly chamshy Llsing the hot ga Ifil1er rod meUlOd fered ltmd thoroughly cleaned described helow
8223 Mating urfaces should be 8231 The welding gas can be cleaned using a proprietary nitrooen or compressed air solvent cleaner to remove and shltlll b fIltered free grease and slightly etch the from suspended water oil surface vapour and particulate
matter 8224 The cement should be
applied a quickly a 8232 The filler rods shall be possible to the socket and made from material to r pigot over the full area of compatible with the matshythe mating surface are eriaJ being welded should be taken to avoid the use of excessive 8233 Butt weld joints shall be cement bevelled to an included
angle of 60deg to 90deg and 8225 The posi liolling of the joint where po sibl welds shall
mUSl be achieved immedshy be fully penetrated from iately after the cement i both ide of the work applied aJld surplus cement removed
10
DW154 Specificatiol for Plastics Ductwork
8234 The joint face and the filler rod surfaces must be clean and grease fre and preferably roughened b shyfore welding In particular any deposited filler rod that is charred mu t be scraped away before additional runs are added
8235 The numbers of runs of fi lIer rod shall be sufficient to give a thiekne s of era s section of the veld at least equal to the thiekn s of the sheet
8236 Where high frequency park testing i specified lhi shall be undertaken in accordance with tbe weldshying in tmction handbook
Note A full descriplion of welding method is given in the Welding Institut handboo entitled Data on Welding of Thennoplastic Relevant BS amp CE Standards are prEN 12814-1 amp 2 prE 13067 and prE 13100-1
824 Completion of compo ite laminate joints Following solvent ementing or hot air welding of joints campi tion of any specified external laminate shall
carried out to maintain thebe
825
integrity of the construction (S 8227)
Gaskets These can be fabricated from various materials in the form of a pre-formed roll she t or trip applied between opposing faces of fbnced ross joints It i a visable to select material r commended by th ga ket manufacturer for the pecific appucation intended
PART 3
Rectangula ucts
9 RECTANGULAR DUCT SIZES
91 This specification covers duct size up to a rnLltimum longer ide of I -00 mm Duct size with an a peet ralio greater than 4 I ar not recommended Although they offer no problems of construction they increase friclionaJ resi tance and the pos ibility of Dois
10 CONSTRUCTION
101 General Th minimum constructional requiJement r r UPVC and PPPPS un-reinforced are hown in able 2
102 Longitudinal seams Longitudinal seams should Dot be located at corners or in the underside of the duct
103 Sheet jointing seams Seams shall be joined by continuous filler rod hot air welding or by fl1sion Vi ldiug only other form of jointing are not acceptable
104 Socket and spigot joints Sock t and spigot joints shall be formed by purpoe made double cket pi ces 100 mm long and of the ame thiekne material as the duct welded into position on each standard length of duet forming 50 mm de p sockets prepared and ready for final jointing on site with filler [Od of the ame formulation used for prefabrication (See Table 2)
105 Flanged joints
1051 FJa ges Fabricated flanges shall b con tmeted u ing miniumum of 9 mm thick by 50 nun wide material of matching formulation depending on duel size as hown in Table 2 The flange hall be mounted true and square to the duct surface and w lded on both sides a 103 and Figs 3 4 Alternative con truction Illay be
11
DW154 Spedjicfltiotl for Plastics Ductwork
utilised for attacllment to plant or other equipment
1052 Drillings Drjllings shall be placed to permit clearance to tbe extel11al casing and any reinforcement of tbe ductwork for the application of fastening
1053 Fastenings For nonnaJ application bright zinc plated bolts nuts and vashers hall be Llsed in sizes and pitch centres shown in Tabl 3 Where special conditions prevail consideration of other material finishes such as stainless steel bolpounds nuts and washers may be used In all cases gasket materials as Section 825 shaLL be used
106 Expansion joints Wher the configuration of the ductwork does not provide for movement due to temperature change or where such movement is restricted by branches or attachmenL expansion joints should be specified by the designer (See Section 18 FlexibleExpansion joint connections)
It is the re ponsibilir-y of the designer to identify the positions of any necessary expansion joints hased upon design param ters for the individual systems (See Figs 23 to 25 34 amp 35)
Design ote xamples of expansion joints shown in Figs 23 to 25 are not suitable for movement exceeding 30 mm
107 StilJeners
1071 External stiffeners Shall be fitted as specified in Tables 2 amp 10 and Figs 5 amp 6
1072 I temal stiffeners The u e of internal stiffening or bracing shall be acceptable iJ deemed necesary and approved by the designer (See Fig 7)
11 FITTINGS
111 Standardisation of fiuings The terminology and descriptions of rectangular duct fittings a et out in Section 25 are recommended for adoption as standard practice to provide common terms of reference for desi crners quantity surveyor and ductwork contractors and for those using computer in ductwork design and fabrication
Bend are designated as hard or easy and the e terms as used herein have the folJowin o
meanings
Hard signifies rotation in the plane of tb longer side of the cross ection
Easy signiiies rotation in the plane of the shorter side of the cros section
An example iIlu trating these term ] given in Fig 8
Fitting are fabricated by cutting and welding sheet
112 Stiffeners Shall be as 107 and Tables 2 amp 10
113 Splitters Shall be as shown in Fig 41 and welded as 1003
114 ruing vanes Where square bends are required turning vanes as shown in Fig 9 hall be fitted
115 Branches When fitting branch ducts to a main duct care should be taken to ensure that the rigidity- of the duct panel is maintained in terms of tbe sti ffenillg criteria
116 Change shapes Where a change bape is necessary to acconUllOdate the duct and the cross- ectional area is to be maintained the slope haU not exceed 225deg 011 any side (See Figs 52 to 56) Where a change in shape includes a local reduction in duct cras - ectionaJ area the slope should not exceed ISO on any side and tbe reduction in area should not exceed 20 Where tceper angles are necessary due to ile
12
DW154 Spec([icatirJ1l for Plastics Ductwork
restucllOn splitters shall be provided Taper Transformation pieces from circular 10 square pieces reducers and transformation piec s or rectangular shall be made as long a shall be manufactured from the tbickl1 s of p sible and uJe angl ball be uot mor than material specified for the larger size ducl 225 (Fig 55)
loon Pa 1500 Pa
2 3 4 5 6 mm mm mm mm
3 socket amp spigot - - -or tlanged
as Figs 1 2 3 401 to 600 45 flanged 50 x 9 flat 1200 800
50 x 9 flat welded both sides a Fig 3 as Fig 5
601 to 1000 45 flnged 50 x 9 flat 800 600 50 x 9 flat welded both sides as Fig 3 as Fig 5
1001 to 1500 6 anged 75 x 9 flat 600 600 75 x 9 flat welded botb sides as Fig 3 as FieJ 5
or or 70 x 70 x 9 angle 50 x 50 x 5 angle
as Fig 4 welded both sides as Fig 6
N t For constructional operating temp rature limits refer to Part 2 Clause 54
Longer Pitch Bolt Size
Side max 2
mm 1m mm Up to 400 100 8 with washers 401-600 tOO 10 with washers
601middot1000 100 10 with wash rs 1001-1500 100 10 with oycrsized
washer
13
Table 2 inimum con tructional requi ments - rectangUlar nmiddotreinforce UPVC and pp
Joints Sliffeners Maximum spacinOLonger Side MillirnUlll She t between
Thickness Joint~S(iffi ners
mm Up to 400
DW154 SpedflCiltion for Plastics Ductwork
Cross joint - recta gular ducts
Fig 1 Socket and spigot joint (UPVC and PP)
Conlinuou weld joint on sile onlinuou- wcld
CT~r~T2
Fig 3 Flange joint (UPVC and PP)
ontinuou weld
Fig 2 Socket and spigot joint (UPVC only)
Fig 4 Flange joint (UPVC and PP)
S iffeners - rectangular ducts
Fig 5 Flat Fig6 Angle
Oatim wo]
Fig8 Bends - examples of hardTie rod assembly and easy
Hard
Fig7 With spacers Easy
4
DW154 Speci(uariml for Plastics Ductwork
Fig 9 Turning Vanes
HOWl G TYl AL EXAMPLE OF FOCI G
15
Ma vane length shy 615 mm
Example ofbraemg when V1IIle length exeeed max pennined Ahematively two banks of ncs fixmg the centre rail together at ] 50 mm nrrcs
U~_II---- fixed to dnct wall both CDds
bLEVATION
vane
Maximum distance between centrc oflUming vanes should [Jot exceed 60 mm pitch
DW154 SPCCijicllfiull for Plastics Ductwork
practice to provide common terms ofPA T4 reference for designers quantiry urveyor and
Circular Ducts
12 CIRCULAR DUCT SIZES Th duct sizes [n Table 4 have been selected from the ISO and C standard ranges as the 132 preferreod sizes
Table 4 Circular ducts shystandard extruded tube sizes
133 Extruded tube
ISO Standard Sizes (Nominal Diameter) 11
Wan Wall Thickness Thickness
mm mm mm mm 110 500 4022
I25160 600 50 I25200 630 60
225 25 700 60 13425250 800 63
280 900 70 315
23 23 80
355 1000
25 1250 104 400 32 1400 108 450 35
Note The above sizes are subject to normal manufactl1ring tolerances Other size may be available in varying wall Lhicknesses and subject to test and operational pressure
13 CONSTRue ION
13 General Tllis specification covers duct sizes up to a maximum diameter of 1500 mm The minimum constructional requirements for UPVC amp PPPPS un-reinforced ducts sball be as Tables 6 amp 7
ductwork contractors and tho e using computers in ductwork design and fabrication The requirements for circular duct fittings apply throughout the size ranges covered in this specification
Sheet jointing seams Seams shall be joined either by continuous fLiJer rod hot air welding or by fu ion welding Other forms of jointing are not acceptable
Socket and Sl)igot joints Socket and spigot joints shall be formed by purpose made double socket pieces 100 mm long and of the same thickness material as tJJe duct welded into position on each tandard length of duct forming 50 mm deep sockets prepared and ready for final jointing on ite with PVC adhesive andor fill r rod of the same formulation used for fabrication
Flanged joints
1341 Flanges abricated flanges shall be conshy
structed using minimum of 9 mm thick by 50 mm wide material of matching formulation depending on duct size as shown in Tables 6 amp 7 The flange shall be mounted true and square to the duct surfaces and welded OD both sides a 103 and Fig 12
1342 Drilliogs Drilling ball be placed to permit clearance to the external casing and any reinforcement of the ductwork
1343 Fastenings For normal application bright zinc plated bolts nuts and washers hall
16
For srualler diameters preformed fittings are available otberwise fitting are fabricated from segments of duct or sheet welded together
The terminology and description of circular duct tiltings as set Ollt in Section 25 are recommended for adoption as standard
be used in sizes and pitCh centres shown in Table S Wh re special conditions prevail consideration of other material finishes such as stain le steel bolt nuts and wasbers shall be u ed In all ca cs gasket materials as Seciion 825 shall be USed
DW154 Speciliwriml for Plastics Ductwork
135 Stiffeners
1351 External stiffeners Shall be fitted as specified in Tables 67amp 1 I and Fig 13
1352 Internal stiffeners The use of internal stiffening or bracing hall be acceptable if deemed neces ary and appn ved by the designer
f 36 Expansion joints Where the corrfiguration of the ductwork does not provide for movement due to temperature
Cross joints - circular ducts
change or where such movement is restricted by branches or attachments expansion joints should be fitted (See Section 18 Flexible Expansion joint connections)
It is the responsibiLity of the designer to identify the position of any necessary expansion joints based upon design parameters for the individual systems (See Figs 23 24 2534 amp 35)
Design Note Examples of expansion joints shown are not suitable for movement exceeding 30 mm
Fig 10 Socket and spigot joint (UPVC and PP)
ConLinuous weld joim on ite Ontinuous weld
crlr~l
Fig 12 Flange joint (UPVC and PP)
Continllous wcld
boil
Continuous weld or Solvelll cement
Solvelll ccmcnl joim on sile
Fig 11 Socket and spigot joint (UPVC only)
Stiffeners - circular ducts Table 5 Fastening centres shycircular duct flange jointsFig13 Flat
flat conljnlJou~ly welded Diameter Pitch Bolt Size
max
1 2 J 11
1 shy -~
mm mm mm Up to 600 100 8 with washers
601middot1000 100 10 with washers - ---I
1001middot1500 100 10 with oversized washers
1
Minimum offourfixings
17
DW154 Specifiiutiofl for Plastics Ductwork
Table 6 constructional quiremen s - circular unshy inforced U VC
Diameter Minimum Joints Stiffeners Maximum spa ~in r
Sheet between Thickness Jointsl tiffcners
1000 Pa 1500 Pa
1 2 3 4 5 6 UD mm mm mm mm
UO to 600 3 socket amp spigot as Figs 10 11
or fla ged Fig 12
601 to 1000 45 socket amp spigot 50 x 9 flat 2400 2400 as Figs 10 11 welded bo sides
or Oanged as Fig 13 as Fig 12
1001 to 1500 6 Hanged 75 x 9 flat 1200 1200 as Fig 2 welded both ides
as Fig 13
Applies 10 Tables 6 alld 7
Note 1 For constructional operating temperature limit refer to Part 2 luu 54 2 To allow for conicleration or extruded se lions or fabricated component the materia] tllicknes i hawn a nominal
Table 7 Minimu onstrucfional requirements shy circular un-reinforced PPS and
Diameter Minimum Joints Stiffcners Maximum pacio Sheet between
Thickness Join sStiffener 1000 Pa 150n Pa
I 2 3 4 6 mm m m mm
110 to 500 3 socket amp spigot as Fig 10 or flaoged as Fig 12
501 to 750 45 ocket amp spi~ot
as Fi 10 or Uanged as Fig 12
751 to 1000 6 tlanged 50 x 9 Oat UOO 12 0 as Fig 12 welded nth sides
as Fig 13 1 1 to 1250 6 flanged 75 x 9 flat 800shy 800
as Fig 12 welded both sides as Fig 13
1251to~ flangcd 75 x 9 Oat 600 600 as Fig 12 welded both sides
as Fig 13
18
DW154 Sped(icalirm for Plastics Ductwork
PARTS
Hangers an Suppo ts
14 GENERA
141 Supports are an e sentiaJ part of me ductwork system and their supply and in tallation are normally the responsibility of the ductwork contractor The principl s are a I-rvCA publication DWIl44 Part 6 Section 19 and should be read in conjunction with this document
Design Note Designers may pecify specific requirements wbich will supersede guidance given in DW144
142 Rectangular ducts abl 8 give the- minimum requirements for
hanger and supports for un-reinforced ductwork
143 Circular ducts Table 9 gives the minimum requirements for hangers and upports for uD-reinforced ductwork
144 Vertical d cts The design of supports for vertical duct is dictated by site condition and where practical duc hould be upported at 4000 mm interval or where tbey pa s through a floor (but n ver exceeding 4500 mm) see Figs 17 amp J8
145 External ducts Where ducts are external to buildings and may be ubject to wind loading support should be plac d so as to restrain ide tl1ruSt and should allow axial movement as neces ary It is the respon ibility of me de igner to calculate the effect of the particular prevailing condition and to define any special upport requirement
146 Expansion joints Support shall be designed to permit axial movement only and shall e provided on eitl1er ide of expansion joint
I 1shy
I~
mm -Jp to 400
401 to 600 601 to 1000
Table B Hangers and Supports - rectangular horizontal ducts
Hanger Bearer Drop Roll Formed Rod
Long r Side
Cbannel ~-shy ~
---shy
Maximum ~pacing
4 52 3 _ -c Fig 15 - Figs 14 15 16 amp 2J
shy
mmm mmmm 240025 x 25 x 16 40 x 20 x 15 8 240040x20x15 40x 20 x 15 10 240040 x 20 x 1~510 40 x 20 x 15
shy
I
40 x 40 x 15 40 x 40 x 15 24001001 to 1500 I 10
Table 9 Hangers and Supports - circular horizontal ducts
Longer Side Hanoer Split Clips Maximum spacing Drop Roll f-ormed and Wrap-round Rod ~hannel Hang r
2 3 4I Fig 1920 amp 22Fig I
mm mmmm mm mm 25 x 25 x 15 IIp to 355 8 40 x 3- --1-_ 2400
2400
2400 2400
70x 6
40 x 5 SOx 5
40 x 20 x 15 40 x 20 x 15 40 x 40 15
10 10 10
356 to 600 601 to 1000 1001 to 1500
19
DW154 Spccijicutioll for Plastics Ductwork
147 Protection specification Any special coatingpaint Unless otherwise stated all support shall be finishes for protection against hostile manufactured in material as specified in this environments shall be advised by the designer
SUPPORT BEARERS
~ 14 Flg16 Inverted profile
angle I ~lIed steel
channel (alternatives) Fig 15 Profile channel (alternatives)
TYPICmiddotAL VERTICAL DUCT SUPPORTS Flat bar clipStiffening frame Outline ofinsulation stiffening frame or tlanged joint (if applicable) or flanged joint
Stiffening framc or flanged Joint
~~-I ( ee notes 10) I
r--~ -++- ~--4==J===4~---
Fig 17 Vertical rectangular ducts Fig18 Vertical circular ducts
The support bearer which depending on ducti tructural opening size could be either channel or angle section may be ll1ilised in any of the following arrangementsshy
a) To support the underside of a flat bar clip in halves (circular)
b) To support the underidc of either the stiffening frame oftbe flanged joint ofaoy duct section
c) To support either a stiffening frame Or a flanged joint below nsing drop rod srudding
20
DW154 Spediraiml for Plastics Ductwork
Arrangement of bearers and hangers (to be read in conjunction with Table 8 amp 9
wbich list material sizes relative 10 duel izes)
KEY Limits refer to actual duct size - insulation is additional - Typical
attachmentv -Atta hment t strucUlrcI to strucUlrc
I I
I - Flat Bar
I - Drop rod or - utlinc of lllddmg In ulillwn (if
applicable)
Alternative 7 drop rod or rt------------ 1 studdmg q I
I I Rectangular
ii i n 1
Fig 21 Rolled or profiled bearer Limit oncFig 19 Wrap-round hanger Limit 55 DIA
V v Drop rod orAllernaUC 1 1 tudding
drop rod or 1
-- -- 1studding and elded bas 1
I I0 -_
Limit 355 DIA Frg 22 Split clips Limit 1500 DIAFig 20 Flat strap hanger amp split clips
21
DW154 Specification for Plastics Ductwork
6PA deElned in J62 appropriate to the airflow pressure acoustic temperature and corrosion
General
15 ACCESSl SPECTION OPENINGS
151 General These are for inspectionservici ng on 1y
HVCA publication DWIl44 Part 7 - General Section 20 sets out the requirements for access applicable to this specification
152 Cleaningmaintenance Designers shall take specialist advice and then stipulate their requirements for the periodic internal cleaningmaintenance of ductwork and of the consequent need for adequate access for specialist cleaning equipment including the size type and locationfrequency of the actual access openings required
Appendix D sets out guidance notes for the consideration of cleaning access and also makes reference to the HVCA publication TR 17 Guide to Good Practice Cleanliness of Ventilation Systems which covers the su~ject
in greater detail
Note A majority of in tallations in which plastic ductwork is used are considered to have a nigb operational risk potential and provision of access should address this
16 REGULATI G DAMPERS
161 General Balancing dampers and control dampers are elements inserted into an air di tribution system or element of an air distribution sy middottem Balancng dampers permit modification of the air resistance of tbe system and consequently cbanging of the airflow rate Control dampers control tlle airflow rate and may in addition provide low leakage closure of the airflow
The deigner shall specify damper locations taking into consideration that good design practice requires a minimum of five times the diameter or width of the shortest side of uninterrupted flow between plant connections and the damper and select the damper type as
characteristics
1611 Balancing damper To achieve the required distribution of air in the ductwork system at inlets andor outlets for [hi purpose the damper blades are set and Jocked manually in position between fully open and fully closed
1612 Control damper To secure dynamic control of the air now in the ductwork system In thi function the damper will always be power actuated and may require to be modulated between fully open and fully closed and to be capable of taking up any position between these extremes In the fully open position the damper should have a minimum pressure drop In the fully closed position it will not necessarily achieve a complete shut off
162 Types of airflow control dampers Airflow dampers of various types are available for specific purposes as follows
1621 Single - blade dampers Single-blade dampers shall consist of a si ngle pi voted blade cOlllained withjn a casing or section of ductwork The blade shall be adjustable tbmugh a nominal 90 angle by means of a quadrant or similar operating mechanism Where automatic control of the damper is required the spindle shall be extended to enable a powered actllator to be mounted
Single-blade dampers shall have a maximum duct width of 400 nUll and a maximum duct height of 400 mm for rectangular ducts and for circular ducts a maximum diameter of 400 mm
1622 Multi-blade dampers Multi-blade dampers shall consist of a number of pivoted blades contained within a casing The blades shall be
22
DW154 Sedicalirm for Plastics Ductwork
adju table through a nominal 90deg angle simultaneously by intershyconnected linkage or gears connected to a quadrant or similar operating mecbanism Where automatic control of a damper is required a spindle shall be extended to enable a powered achlator to be mounted
There is no restriction on the size of duct in which multi-blade dampers or damper assemblie may be u ed Where dampers are required for blade lengths in excess of 750 mm the blades should be suitably reinforced or supponed 0
individual damper blade should exceed 200 mm in width
1623 Iris dampers Lris dampers shall consist of a nUlllber of radialty interconnected blades which open or close within a casing with duct COlll1cctions The blade shall be simultaneously adjusted by a quadrant or similar operating mechanism
Iris dampers shall be installed as specified by the manufacturers operating and installation instructions where the product is unidirectional with regard to airflow
lris dampers are available for circular ducts only in diameters up to 250 mm (it should be noted that the damper casin i appro)(imately twice the diameter of the duct)
1624 Backdraught dampers Air pressure operated uni-directional rectangular (single or multi-blade) with adapters if fitted to circular ducts
1625 Slide and blast gate dampers A damper [lsed as a shut off facility with an externaJ Lide bousing allowing the blade configuration to be fuJly inserted to fully extended for maxiDlUlll air flow
163 Construction
1631 Materials All products shall be protected against cOHosion as necessary and supplied in a fully finished condition as specified by the designer
1632 Dampers used in low and medium pressure systems The following recommendations apply to dampers forming an integral part of ducrwork with pressure classifications A and B air leakage limits
The dampers shaH be constructed to minimise distortion and prevent jammin in operation Th blade shall be sufficiently rigid to minimise movement when in the locked pOSitiOLl
The blades shall be securely fixed to the operating mechanism All balancing dampers shall have a locking device located on the outsid of the case and shall giv clear indication of the actlwl blad position All penetrations of the duct shall be fitted with suitable seals where necessary
1633 Dampers used in high pressure systems Regulatino- dampers used in duc[work sy tems to pressure cJassification C shall meet tbe construction requireshyments specified in 1631 and 1632 with operating mechanisms out of the air-stream
1634 Proprietary types of damper The use of any specific type of proprietary damper shall be confirmed by the designer In all cases proprietary dampers shall meet the relevant requirements of thi specification
1635 Damper casings Duct damper casings hall be constructed to meet th mllllmum
23
DW154 SpeciJimlioll for Plastics Ductwork
leakage Iim its sp cified for th c1uctwork ystem to which tbey are installed
In order to apply the square metre leakage calculatio as detailed in DW143 A Practical Guide to Ductwork Leakage Testing the reference casing area ball be taken as the perimeter ize of lh damper IDultipli d by the equi alent length of Imetr eg an 800 mm x 400 mm duct damper hall have a surface area for casillg leakag p donnan calculated as follow (2 x 08) + (2 x 04 x I
=24m2 casing area
Other pelforlllance ancl rating test methods for damp f and valves are specified in ISO 5129 and BSIE 1751 and are referenced belm a) Leakage past a closed damper
alve BSIE 1751 b) low ratepre sure requirement
characteri t cs BSIE 1751 c) Operational torque le ring
BSEN 1751 cl) Thermal transfer testing
BSIEN 17 I e) Reg nerated sound power levels
ISO 5129
164 Installation Dampers shall be imaalled in accordance will) any re Ievant ISO EN or British Standard 10 aJ bUT lcling regulation and national code of practice as well as the manufacturers recommendations
17 FIRE DAMPERS AND INT MESCENT SLEEVES
171 General Damper or sleeves arc requiTed on duct y~telll where the designer has -tjpulated the
duct wiU penetrate a fire compartment in the majority of application tbermopla ti ductwork is ugtecl where contamlDated corro ive or otherwise exceptional fumes are concerned it is preferable to use tire damp r which are externalJy mounted ie of the intmnescent operated crush typ
24
72 Fit-e rating The damper assembly should have a fUT
resi tance ratin o equal to that of the fir ban-jer it penetrate and ball be fire tested and rated to the timetemperature curv of B 476 Part 20 and 22
173 Intumescent sleeve At the time of writing this specification qualified test results were available for rectangular dampers and circular dampers up to 55 mm diamet r Manufacture have indicated that they are able t provide speci fications for other size and diameters This infonnation should be confirmed b th de igner Various type are available includino
tho e incorporating ruechanical closing plate and those operated anI by expanded iJllUme c nt media
In all ca es fire damp rs and intnmeBcen leeves shall be supplied and in taUed in
accordance with the manufacturer iJlStructioos and COSHH a essm nt
174 Other types Fire dampers of mious types are availabl for specific purpose~ ee HVCA publication DW144 The de igner should )lot (hat materials for con lt1Jction bould be uitablc for the par1icular application
ALL C SES FIRE DAMPERS AND fNT MESCENT SL _VES SHALL HE S PPLTED AND INSTALLED IN A ORDA CE WITH Tf--IE MANUshyPACTURERS STRUCTTONS AND COSHH ASSESSMENT
18 FLEXIBLEEXPANSION dOINT CONNECTIONS
181 General ploperties Tbe material u ed for flexibleexpan ion iojnt~
mu t meet the design r requirements for temperature air pressllrelfe resistance applicable to pl astic duct sy tem vibration and noi e br akout when incorporated into a jointconnection and shall comply ith lh standard of air-tigbtne specifi cl for the duct work sy tem of which it fOlms part (See Figs 23 24 5 26 27 amp 28 for typical con truclion clelai Is
DW154 SJecilimtol for Plastics Ductwork
Expansion joints
Fig23 Moulded bellows type (rectangular and circular)
Fig24
~F aiblc sleeve
__ liding sleeve
~~~~
Sleeve type (circufar)
Fig 25
AIRFLO
COnlinuou~
weld~
Flexible Iceve
PV A HOWN pp SE BACKING FLATS AS FIG 2
Sliding lee c Co1linuou
weld
Flanged sleeve (rectangular and circular)
25
DW154 Specificatiol for Plastics Ductwork
Flexible con ections
Fig 26 Flexible sleeve with clips (UPVC and PP)
--__ Flexible I eve
I
I
I CODn clioD to plant ~
Band clip
Fig27 Welded flexible sleeve (UPVC only)
Plastic)sed PVC slceve ~-- onll11uo1sly welded
onrreclion to planl ~
Fig28 Flanged flexible connection (UPVC and P )
t sp dally moulded flexible flanged connCClitlll
boil
C)nneclion to plant ~
26
DW154 Specificotiol for Plastics Ductwork
182 LOClt1tion Flexible joint are typicltllly lIsed at building expansion joint and fan inletsoutlets Any others required should be indicated on the de ign drawings Care should be taken to maintain alignment across jointsconnections
183 Length Flexible Jomts shall be kept as short as pra middottieable above a minimum eft ctive length of SO mm In no ca e shall a flexible joint exceed 250 mm in lengtb
184 Connections to rectang a ducts With flanged rectangular connections Ule tlexible material shall be held in pLace with flat pIa tic strip of not less U1an 6 mm thick ltlttached to the flanges using uitabJe fixings The more heavy weight type of fleAible mateLial may also be obtained formed into a channel ection with corners fitted to give a neat air tight j int For pigot connections the Be ible material shall b held in place with flat pIa tic trips n t less than 6 mm thick
t 85 Connections to circular ducts With tlanged circular connections the flexibl material shall be held in place with flat plastic backing strips or proprietary clip bands with screw or toggle fast ners
186 Welded flexible connections (Rectangular and Circular) Where the parent and llexibl material are from imilar ba ed products they can be joined to the duct u ing the welding method described in Section 823
19 PROTECT VE FINISHES
191 nles otherwise stated all ductwork shall be mallllfactured in mat fial as pecified in tbis specification Any special coatingpaint fmishes to be provid d by the duct work contractor sball be advisd by th de igner
20 CONNECTIONS TO BUILDING OPENINGS
201 Fanning and finishing building op nings are not the repoJlsibjlity of the duftw( rk contractor and the note that follow are for guidance purpo e only
2011 Openings in brick block or concrete walls shall have inset frames to provide a suitable means of fixing grille louver masking flanges or the tlanged ends of ductwork The illset frames shall be conslnlcted to maintain the structural int grity of the wlll and where applicable cavities shall be suitably lined
2012 Openin s in dry linino partItIons shall have inset frames a 2011
2013 Openjngs in cladding walls and roofs shall have flaoged leevesframes to provide a suitable means of fixing a 2011
2014 Horizontal and vertical opening xposed to oLltside atmo phere hall
be provided with a suitable weathering fini h at the external face especially where profiled cladding is used
2015 Timber framed op nings are not permitted In fj re compart ment barriers
202 Ductwork connections to building openings hall have a flange of suitable profile to permit practical fixing to the openillg frame In selecting the profile consideration shall be given to Tabl~s 2 and 10 in this specitication relating to duct ize and rating Gasket strip or sealant shall be ltlpplied between the tJaoge and building op ning frame
21 DISCHARGEEXHAUST TERMINAL
21 Tbese shall be vertical open ended and designed to meet and comply with current r gularions on contaminated flue The designer hall ensure that the de ign and perf rmance i suitable for its intended purpose Examples of some typical terminal designs are SbOiD in Figbull 102 10 bull 104 amp 105
27
DW154 SpedjimioTl for Plastics Ductwork
22 THERMAL INSULATION
221 The provision and application of thermal insulation to ductwork is not the responsibility of the ductwork contractor
222 Where ductwork is required to be preshyinsulated the specification should be agreed with tbe designer
223 Where the temperature of the air within the duct promotes condensation on the exterior surface of the duct and cause moisture penetration througb the thermal insulation vapour scaling may be required and in this case the most important requirement is to limit penetration of the seal
The extent of any vapour sealing of ductwork thermal insulation and the support method to be u ed must be clearly pecitled in advance by the designer
224 For detailed information on the thermal insulation of ductwork reference should be made to BS 5422 1990 which covers the specification for thermal insulation materials on pipes ductwork and equipment (in the temperature range -40degC to +700degC) and BS 5970 1992 which is a Code of Practic for Thermal Insulation of Pipework and Equipment (in the temperature range -lOOdegC to +870degC)
23 FIRE RETARDANT FINISHES ON PLAST C DUCTWORK
231 The designer should note tbat ductwork constructed to DW154 has no teted fire rating or information see Appendix C
24 REINFORCEMENT OF DUCTS WITH GRP LAMINATE
241 General Where ductwork is required in larg T izes than are covered by Tables 2 4 6 amp 7 or with the increased strength sometimes necessary for industrial use external reinforcement is normally pwvided by applicatioD of glass fibreresin laminate
GRP systems will bond satisfactorily with standard UPVC sheet but for pp it is
nece sary to use a specially prepared sheet with a glass fabric backing incorporated dOling manufactllfe
The detailed techniques of fabrication using GRP are outside the scope of this speci lcation but the following notes are offered for guidance of ductwork fabricators
242 Materials
2421 Quality The laminate is made up of polyester resin complying with BS 3532 and glass fibre complying with BS 3496 or BS 3749 The nominal ratio of resin to glass fibre should be 7030 by weight
2422 Minimum properties The laminate shall comply with the followiog mini mum pbysical properties
Tensile strength - 70 MNm Tensile modulus - 7 Gl m Flexural strength - 140 M Im Bond strength (hetween laminate and substrate Not less than 7MNm Bmcol hardnes Not le s than manufacturers specification
The GRP reinforcement educe the expansion of the parent material but the resultant stre ses arc well within rhe strength of the bond However the Iinear thermal expansion curve shown in Figs 34 amp 35 will serve as a guide
Surface resistivity electrkal propcltles and acoustical propertie are similar to the relevanl unreinforced materials The fire retarding properties of GRP may be improved by the use of specialisl laminating resin
2423 Forms available GRP Laminate should be built up from the separate materials ie resin aod glass fibre in the form of chopped
I strand mat or spray ravings
28
DW154 Spcification for Plastics Ductwork
2424 Workshop conditions Polyester resuls are sensItIve to lmperature and the workshop hould b maintained at a temperature of herween 20deg and 25degC HiOh relative humidities and damp onditions should be avoided A good rate of air change must be pro icled pJeferably by m chanical ventilation
2425 Storage of materials Resin and urin o agents shouJd be stored in dark cool condirions away from the working area and in confonnit with statutor requireshyments for tJle middottorage of flarmnable liquid Because of Ule Limited torage lif of the unmixed resin and curing a eot mal lials ~hould be ch eked before use to enLlfe that they are within the manufacturer pe ified sh If life (usually ix month from the dm of manufacrure)
Glass fi re should be stored separately und r clean dry conditions
243 Surface preparafon
2431 UPVC To achieve the specified bond strengtll the urface to which the GRP is applied mut first be thoroughly cleaned and then etched either by mechanical means or by the use of a suitable solvent
2432 pp with glass fabric backing To achieve the specified bond middottrength the fabric backing must be thoroughly impregnated Witll resin
244 Mixing the materials for use The re in 1 a three part mix compri lng base I sin hardener and accelerator The manufactur rs pecj[ied proportions are critical and th llUxmg sequenc pecified must be meticulously foUowed
The resin has a very limited life after mixing and before u e It is dependent on the characteri tics and bulk of th resin the alllount of hardener the degree and method of acceleration and the workshop onditions
245 Methods of application
2451 General The mixed resin may be applied by hand or b pray c1epoition The operation must b completed within the gel time of th y tern and tbe laminat fully cOI1olidated to achi v the phy ieal properties pecified
2452 Hand lay-up The duct surface i coated by hand with resin Llsing a brush and a mar of gla fibp orked in until full consolidation achieved Th proc is repeated untiJ th requird thicknes i obtained
2453 Spray depo Won The duct surface is coated WiUl re in by spray gun with the chopped glass roving added through a separate nozzle The full thickne i obtain d in layer with con olidation of each layer by hand roller
246 Construction
2461 General M ini mum COllst ructional requireshyments are pe itied ill Tabl 10 for rectangular and Table 1J for circular dUClS
2462 Joints and stiffeners Fig 29 30 31 32 amp 33 hoI TOSS
joint and tiffener for reinforced UPVC and PBPP duct
247 Worki g practices The fabrication of ductwork pecifiecl ill thi document i not affected by the addition of GRP
29
DW154 SfJcdJicatiOt for Plastics Ductwork
Table 10 Minimum constructional requirements shy
Longer Side Minimum Sheet Thicknes and
GRP Reinforcement
UPVC FBIPP 1 2 3
mm mm mm Up to 1000 3 plus 3 plus
06 kgm2 06 kgOIl GRP GRP
1001 to 2250 45 plus 3 plus 06 kgm 12 kgm
GRP GRP
2251 to 3000 45 plus 6 plus 12 kgm 12 kgm
GRP GRP
Cross Joints
UPVCFBPP 4
mm socket amp spigot
as Fig 30 or flanged as Fig 29
75 x 9 flange welded on both sides as Fig 29
75 x 9 tlange welded on both sides as Fig 29
rectangular GRP reinforced ducts
SlifTeners Maximum Spacing Between
JointsSljffeners UPVCIFBIPP UPVCFBPP
5 6 mm mm
75 x 9 flat 800 as Fig 31 or
50 x 50 x 5 plastic or MS inverted angle as Fig 32
or tormer as Fig 33
75 x 9 flat 600 as Fig 31 or
50 x 50 x 5 plastic or MS inverted angle as Fig 32
or former as Fig 33
75 x 9 flat 600+shyas Fig 31 or 50 x 50 x 5 plastic
or MS inverted angle as Fig 32
or former as Fig 33
Note 1 On rectangular duct up to 400 mm longer side no stiffeners are required 2 Applies to Tables 10 amp I I For COlJstructional operating temperature limits refer to Part 2 clause 5A 3 Tables 10 amp II apply to all pres ure classes up lo ]500 Pa
Table 11
Diameter
1 III
lJp to 1000
1001 to 1750
1751 to 2500
Minimum Sheet Thickness and
GRP Reinforcement
UPVC FBPP 2 3
mm mm 3 plus 3 plus
06 kgm 06 kgm GRP GRP
45 plus 3 plus 06 kgm2 18 kgm
GRP GRP
6 plus 6 plus 12 kglm2 18 kgm1
GRP GRP
Cross Joints
UPVCFBPP 4 III
socket amp spigot as Fig 30 or flaoged as Fig 29
75 x 9 flange welded on both sides as Fig 29
75 x 9 flange welded 00
both sides as Fi 29
inforced ducts
Maximum Spacing Between
JointsStiffeners UPVCIFBPP
6 mm 2400
800
600
Stiffencrs
UPVCFBPP 5
mm 50 x 9 flat as Fig 31
75 x 9 flat as Fig 31 or former as Fig 33 75 x 9 tlat as Fig 31 or t()rmer as Fi 33
ote On extruded tube tip to 600mm diameter no stiffenergt are required
30
DW154 Specificatioll for Plastics Ductwork
G - Cross joints and tiffeners
Fig 29 Flange Joint Fig32 Stiffener shy inverted angle
M artiPfCuQkbdd erttpObri) Wl111 RP tlddtlt
_- GRPloliu] lh~
Fig 30 Socket and spigot joint Fig33 Stiffener shy use of former
Fig 31 Stiffener Flat
I Pv FlPP ~ ~lmJaDUA1) d
OMrlQ rrnall 1( tQlS
25 STANDARD COMPONENT DRAWINGS AND ABBREVIATIONS
251 The illustrations in this section not only highlight where applicable geometric limjtations for the de ign and manufacture or ductwork components but also recommend
standard drawing representation terminology and abbreviations for both duetwork components and some of the more commonly used ancillaryplant items
252 Designers and surveyors should note that bills of quantities should provide a full description
3)
---
v
DW154 Spcc(fim(ml for Plastics Ductwork
Fig 34 Linear Thermal Expansion
u c 0 N ro 0)
b 0)
S
sect0
5 oS cl) 0)
~
on ~ ltl
c U
-30 -20 -10 0 10 20 30 40 50 60 70 80 90 TEMPRATURE C
~ V
-
~~c_ ~
~V
V ~
-7 ~
-- ~V ----
v
-6
+14
+12
+10
+8
+6
+4
+2
0
-2
--4
ig 35 Typical Design Stress tor UPVC and P
7
6
r shy 5E
-c E----0 4t) VJ 0)
ci5 0Jl 3
~
0)
Cl
2
1
o
UPVC
1
000
1
1
pp
- r-- shy r----- shy - t--shy I
__0
-30 -20 -10 0 10 20 30 40 50 60 70 80 90 TEMPERATURE C C
Note Figso 14 amp 35 shaded area refers to GRP reinforced duct
32
DW154 Speciicfltirm for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - REC ~NGULAR
Splilt~r Posilion W-mm pliucr
A B c 40]--QOO 1 W - -
601-1000 1 W4 Wf2 -
1001-1800 3 WI W3 W2
FIG DRAWING DETAfiS
tU]36 ATI Straight Duct with socket and spigol joint
rn [037 Straight Duct with flanged joints
[I []38 Straight Duct with flanged joints
rkJ Short Radius Bend
39 Applies to any augl and for duct up to 400 n11n wide
Minimum (I1m31 radills = 100 mm
Medium Radius Bend (a illustrated)
[kJ Applies to any angle
40 Long Radiu Bend Similar but radius = W
Throlll radius = W2 Applies to any angle
- Short Radius Bend with plitlers
I -shy -shy u co - t lt Li--_ 41 t 0 ~ I I I
~ I
L 1W
Minimum waal radius = 100 mm Splitters not required in bend angle less than 45deg
42 QJ1 Square Bend with turning vanes ij
3
DW154 SP(L~ficatioll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - RECTANGULAR
FIG DRAWl G DETADS
43
~
I v
L L Radius Tee with internal deflectors
44
~ Radiussed Twin Bend
45
Imiddot
er Swept Branch
46 U-
Sqoare Tee with Turning Vanes
47
~ f
Breeches Piece
48 0 y l Piece
34
DW154 Specificatioll for Plastics Ductwork
STANDARD COMPONENT RAWINGS - ECTANGULAR
55
54
51
50
53
52
49
FIG
~MX
RAWlNG
DmiddotMAX
EfjMAX
Minimum throat rndius = 100 mm
Rectangular shy Round Transformatioll
Eccentric Taper 225deg max in either plane Spliller are required for angles greater than 225deg and hould bi eet the angle between any side and duct centreline
DETATLS
Angled Offset
OUset Taper Splitters are required for angle greater than 22 0
and shoold bi eet the angl between any side and dUCI centrelinc
Mitred Offset
Concentrk Taper 2250 max in ither plane SpUtters are required for angle greater than 225deg and should bisect the angle between any side and duel c ntreline
Radiussed Offset
35
DW154 Splcilcuthm for Plastics Ductwork
STANDARD COMPONENT DRAWINGS ~ RECTANGU AR
Branch ducl DimCllsions widlh (W) (A)
urnl mm up lO 200 75
300 100 400 125 600 150
Ocr 600 200
FIG DRAWlNG DETAILS
56 poundplusmni~~ Rectan~lar - Flat Oval Transformation
57 [ Square Branch
58 er Angled Branch
Branch dUCI Dimensions wfdth (W) (A)
[- mm mm59 3shy Shoe Branch Up (0 200 75
--shy AIshy + 300 100
400 125
450 MAX 600 150
Over 600 200
Branch duct DimensIOn
rP X width (W) A)
60 - 1--shy _
~ mm mm
Bell Mouth Branch pto 200 75 300 100 t 400 125
600 150 Over 600 200
0=0 61 -
~ Bell Mouth
- shy T 4-5deg M x
--I 1-shy
TJ
62 X I ] I
Tele-scopic Joint I Illustrated with flangeL
X63
SBD Single Bladed Damper
36
---
DW154 Spedicatioll for Plastics Ductwork
STANDARD OMPONENT DRAWINGS - RECTANGULAR
DRAWING DETAILSFIG
64 on-Return DamperNRD shyshy
shyXbull
Multi-Leaf Damper Can be piggoted or flanged oppo cd or parallel blade
Alternative controls areshy
q p [gtshy
J HD65 Hand
~MD otori ed
PO Pneumalic
L-lt
l 13G 66 Blast Gate DamperX X
FireSmoke DampersSleeves
211r Ratinggtshy----
L_-
---
----
r----
Ir-- shy
IL- _-l
2hr
With i tallation frame
67 41 r Rating
4hr
Smoke damper SD
Intumc cent Sleeve L-d
37
DW154 Specijicutiolt for Plastics Ductwork
FIG
68
69
70
71
STANDARD COMPONET DRAWINGS shy REC ANGULAR
DRAVING DETAILS
gtshy Access Openings
AP 6 Access Panel - Rerno able
w [ ~ Access Door - Hinged
I ~le Inspection Cover
le -I reg -lt
~X X Flexible Connection
~ Drop Cheeked Radiussed Twin Bend
U Drop Cheek Bend
I
72 Air Flow SymbolX
38
DW154 Specifim[ioll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - ECTANGULAR
FIG DRAWING DETAILS
73
74
75
76
77
Q
Q
rp---t
~
V- I Ir---I
JL --11
THE ABOVE DETAILS TYPICAL PLENUM
Air Terminal Plenums
Plenum with side connection
Plenum with top connection
Cover plate with connection
Special plenum with connection
elescopic conn ction in direction of air flow
39
DW154 SpecijicotiOll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG
78
79
80
81
DRAWING
-23~---pound3-(MALE) (FEMAJE)
-t=j--_j(--d-shy
--L
~ THROAT RADI S= D AS T NDARD
e ~
THROAT Rjf)lU = D A MU)
DETAILS
Straight Duct With male and female connectors
Straight Duct With flange joint and slip joint
Bend MouldedIFormed Applies to any angle ego 30deg45deg60deg90deg Medium radius bend as illustrated Long radius similar but throat radius 0
Segmented Bend 90deg four section minjmum as illustrated
Other Angles 60deg = 3 sections 45deg = 3 sections 30deg = 2 sections
I
i
40 shy
DW154 Speciicafinll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG DRAWING DETAlLS
82 Segmented Twin Bend Radius = D2 max
May also be fabricated from tube
83 Equal Tee MouldedIFormed
84 -~ 1in Bend MouldedIFormed
85 Taper Concentric 1 0 as iUu trated Eccentric 30deg iJJcLuded angle
86 Short Taper
41
DW154 SpcUicatol1 for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG DRAWING DETAILS
87 30 max Offset
Angle Branch
Bran h dUCI Dimcnsions dia (D) lA)
Shoe Branch mm mm 88 Cl
Off rectanguJur Up 10 200 75 lOO 10 400 125
- 00 150 Over 600 200
Bl1IllCh duct DimenlOns din (D) (A
~-$a-Conical Branch mm mm
89 Also acceptable with Up 10 200 r
full conical surface 300 10
400 125
END VrE -shy 600 150 Over 600 200
90
m 75
100 12 150 200
mm Up to 200
_ 300 400
600 Over 600
iUtred Branch
Shoe Branch
J-L----U ~ Bell oulh Branch
ENDV1EW
93
92
91
42
DW154 Specificatiol for Plastics Ductwork
STANDARD OMPONENT DRAWINGS - CIRCULAR
FIG
94
DRAW G
I
~ 30deg 090deg
Breeches Piece
DETAILS
95 amp-----~ Blank End
~-----p Multi-Leaf Damper Can be piggolcd or fianged opposed or parallel blade
Alternative controls areshyri=-+- L-T~
I
---
LT~
I r- -
-+1
J HO Hand96
bMD Molori cd
PD Pneumatic
tl-shy bull
Single Bladed Damper 97 ~ saD
on-Return Damper Vertical application only 98 m~D
43
DW154 Sf1tcificatioll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG
99
100
101
102
DRAWING
$ I-
2hr
1 4hr
SD
~v I I
CO TINENTAL COWL
DETAILS
Iris Damper
Fi reS moke Dam persSleeves
2hr Ratillg
With installation frame
4br Rating
Smoke damper
Intumescent Sleeve
Access Openings
Access panel - removable
Access door shy hinged
fnspection cover
Discharge Continental Cowl
44
DW154 Sp(Cii(ltJll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
DRAWINGltIC DETAns
-
I
I
~
I I I High Velocity Discharge Terminal 103 I
I
I I
J I I 1 ~--
Offset Stack Discbarge Terminal 104 1
~ I e --(-
I
N
I
I
I~
I I Vertical Oischarge with Weather Cowl 105 I
--1--1 I
I
GAPI I
RTl AL DISC) lARGE WITH W ATIIER COWL
45
DW154 SpecUicatoll for Plastics Ductwork
STANDARD COMPONE T DRAWINGS - PLA TEQUIPMENTIMISCELLANEOU
FIG DRAWING DETAILS
106 ~~~ Rectangular Attenuator
107 ~- Circular Attenuator
108
~ Beod Attenuator
109 J ~(f) Heating Coil
110 J ftte Cooling Coil
III Jc[ Electric Heating Coil
112 X F
Humidifier
113 [H XX Axial Fan
114 ~fB1famp Noo-standard Ductwork Cross hntchillg (of any separate type) indicates by reference to a key any non DVil54 ductwork system
115 2llIIIIJIIIIIll Flexible Ductwork
46
DW154 SJeCUicll(iol1 for Plastics Ductwork
TABLE 12 - STANDARD ABBREVIAT ONS
ABBREVIATION FLL
AD Acces Door
AFF Axial Flow Fan
AHU Air Handling nit
All Aluminium
AP Acess Panel
AT Attenuator
AV Air enninal Unit
BE 81ank nd
BQ Blast ate Damper
CC Cooling Coil
CF Centrifugal Fan
CTA Cross alk Attenuator
CVU Constant Volume Unit
DP Drain Point
EEC Electric Heating Coil
El Expansion Joint
FAl Fresh Air Inlet
FA From Above
FB From Belo
fBPP Fabric Backed Polypropyl-ne Sheet
Flexle Flexible Connection
lexfD Flexible Du t
C False Ceiling CO an oil Unit
fD Fire Damper
FFL Finished Floor Level
FJ Flanged Joint
FOAM Rigid Polyurethane Self xtinguishing Foam
FOB Flat on Bottom
FOT Flat on Top
GAM Galvanised after ManufacttrJc
GRP Glass Reinforced Plastic
GSS Galvanised Sheet Steel
HC Heating oil
HD and controlled Damper
HH Hand Hole
HL High Level
HVD High Velocity Discharge
IC Inspection Cover
ID lri Damper
IFS Intumescent Fircleevc
47
DW154 Specification for Plastics Ductwork
TABLE 12 - STANDAR ABBREVIATION CONTINUED
ABBREVIATION
IU
L
tv1D
MS
NRD NTS
OBO
OE
PHD
PD
PP
PP
PRD
PVC
RFC
RSC
R
SBO
SO
S1 TST
SSL
TA
TB
TO TJ
TP
TV
TV
OS
UPVC
S
V
VAV
50 RSA
FULL
Induction Unit
Low Level
Motor controlled Damper
Mjld Steel
on Return Damper
at to cale
Opposed Blade Damper
Open End
Parallel Blade Damper
Pneumatic controlled Damper
Polypropylene
Self xtinguishing Polypropylene
Pressure Relief Damper
Polyvinyl Chloride
Rolled Form Chamlel
Rolled Steel Channel
R fUnit
Singl Blade Damper
Smoke Damper
Slip Joint
Stainl t el
tructural Slab Level
To Ab vc
To Blow
Top Down (In Direction of Flow)
Telescopic Joint
Test Point
TU111iog Vane
Top Up (In Direction of Flo )
Voles Otherwise Stated
Unpl3sticisecl Polyvinyl Chloride
Underside
Ultra Violet Light
Variable Air Volume
Rolled Steel Angle (Vith Size)
48
DW154 SJeriiflllioll for Plastics Ductwork
A2 DUCT PRESSUREAPPE DXA Ductwork con truct d to DWIl54 will bebullbullbullbullbullbullbullbullbullbullbullbullbullbull
Air Leakage From Ductwork To be read in conjunction with DW143 A practical guide to Ductwork Leakage Testing
CAUTION As highlighted ill both this docul1lenr and DW14 I lot ellough emphasis can be placed 01 the fact that except for high pressure class C the much more stringent ductwork constructional standard brolght about b the general acceptance of DW154 have irtlally negated the requirement for leakage-testing It is essential lO realise lhat except where it is mandatory this doclllllelll is nOl an endors ~lIlent of the rourine testing of ducts bllt purely a guide to outline the procedures for cononnity with the air leakage limits ill Table l Where the specified methods of assembly and
A3sealing of dlcls are u ed a vi ual inspection wil ordinarily sl~fll e for ver(iatioll of a well engineered and a ceptahfy airtight COl1strucrioll WHERE NOT MANDATORY DUCT LEAKAGE TESTING IS GENERALLY AN UNJUSTIFIED AND SUBSTANTIAL EXPENSE
A1 INTRODUCTION L akage from ducted air distribution systems is an Lmportant consideration in the design and operation of ventilatjon and air conditioning middotystems A ductviork t)ystem tbat ba limited air leakag within defiucd limits wiH cnsUft
that tile design characteristics of the sytem can be maintained It wilJ also ensure that energy and operatLonal cosb are maintained at optimum levels DucLwork constlucted and Ulstalled in accordance with DW154 should minimise a level of air leakage that it) appropriate to tll operating static air pre sur in tile system
A4However it is recouuised that tbe environment in wtJich middotystems are installed is not always conducive to achieving a predictable level of quality in term of system ajr leakage and it is therefore accepted that designer may sometimes require tlle ystem to be tested in part or in total It should be ecogni ed that the testing of duct systems add a ignificant cost to the installation and incur some extra tjm within the programme (Se 47 and 64 re mandatory te-sting)
manufactured to a structural standard that is compatible with the system operating pressure There are three classes of duct con truction to eorre pond with the three pre ure clas meations Class A Lo pressure ducts suita le for a maximum positive operating pressure of 500 Pascal and a maximum negative pressure of -500 Pascals Class B IVledium pressure ductmiddot suitable for a rnaxilnuJJl positive operafjn o pressure of 1000 Pascals and a maxllnum negative pre sure of -750 Pa cal Class C High pre sure ducts suitable for a maximum po ilive operating pressur of 2000 Pa cals and a maximum negativ pres ur of -750 Paltcals
LEAKAGE FROM DUCTWORK Leakao-e front pia tic air ducts occur at the joint~ and is therefore proportional to the total surface area orthe du twork in th system Tb level of leakage i imilarly related to tIle air pres ure in th du t system and whilst there LS n precis formula for calculating the level of air los it i generally accepted that leakage will increase in proportjon to pressure to rbe pOvver of 065 The effect of air leakage from high pressure velocit ductwork is critical tn terms of system perfomlan dege energy consumption and the risk of high frequency noise as ociated with leakage These problems are le critical with medium pressure 10 ity systems but should be con idered Low pres mevelocity ducts present the lowe~t
ri k in tenn of tbe effect of leakage on the operation of the s stern
SYSTEM LEAKAGE LOSS As there i no di ct relatLonship between th volume of air conv yed and the surface area f the ductwork sy tern required to match the building configuratmn it is difficult to express air leakage a a percentage of total air volume Similarly the operating pressure will vary throughollt lh 3 system and a leakage is related to pre me the calculations ar comple However it is generally ac epted tbat in typical good quaJjty systems the leakage from
49
DW154 Specificatioll for Plastics Ductwork
each class of duct llnd r operating condition will be io the region of CIa S A low pressure 6 Clas B medium pres un 3 Clas C high pressure 2
A5 SPECIFYING AIR LEAKAGE TESTING Re peeting both the co -t and programme implications a sociated with te ling du 1 for leakage the designer may for example indicate that a particular system is te ted as follow
a) High pressure ducts - all tested b) Medium pr ssure duets - 10 of the
ductwork shall be s eet d at random and tested
c) Low pre sure - unte ed In any case where a random te t i elected for medium pre sure ductmiddot the followin c1au~e is suggested for inclusion by the de ign r
The designer hall elect at random a maxirnwlI of 10 of the dUCl system to bt tested for air leakage The duct hall be tested af the pressure recommended in Table J3 for the assifi atiol for the ectiol1 of the ductwork that is to be tested The tests shall be carried Ollt as the work proceeds and prior to the application of thermal insulation In the event of test failure of the randomlY selected section the designer shall have The right to select two La1her e tiolls at random for resting Where succes ive failures are identified there shall be a Tight to require rhl COl11raCWr 10 apply remedial attention to the complete ductwork system Th contractor shall provide documented eviden e of the calculalions used to arrive (1
the allowable 10 I for the section to be tested and the client or his agent shall willess and sign the results of the test
able 13 Air leakage rates
Maximum leakage of duct work Static
prcssUft Low-pressure edium-prc-sure I Iigh-prebull me diJfercntial Class A Class B Class C
1 2 J 4 Pa Litres per second per quare metre of surface area 100 054 018 ZOO 084 028 300 110 037 400 132 044 500 153 051 600 058 019 700 064 021 800 069 023 900 075 025
1000 080 027 1100 1200 1300 1400 1500
029 030 032 033 035
1600 1700 1800 1900 2000
036 038 039 040 042
Note Recommend d mean test presures are highlighted iD bold type with the actual selection being left to tll test operator
50
DW154 Sfeeiieaioll for Plastics Ductwork
A9
A10
and air leakage classification for the y em under test
DESIGNERS CALCULATIONS The designer can middotaJculate with reasonable accuracy the predicted total loss from a ystem by
a) Calculating the operatin presure in each ection of the sy tern
b) Calculating the surface area of the ductwork in each correspondin pre lire s ction
c) Calulating the allowabl~ los at the operating pressure for each ection of the system (see table 13 for allowable leakage figures)
VARIABLE PRESSUR S IN SYSTEMS De igner can achieve significant co t saving by matchina operating pressures throughout the system to constmctional standard and appropriate air leakage testing eO the practice of specifying construction tandards for whole duct sy tems based on fan discharge pre sure may incur unnece sary costs on a project For example ome large sy terns ould well be classiC ed for I akage limits as follows
Plant room risers CJas C Main floor distriblltJou CIa B Low pre sure outlets Cla A
A6 SPECIAL CASES There may be ~itLlations on a project where circumstance dictate thal pecial consideration be given to containing air loss s eg a long mn of duclwork may incur a di -proportjonate level of air 10 s In ca es such as thi example the designer can specify an improved tandard of airtighmess ie 80 of alJo~able 10 s for la B Ju ts The designer sbould not specif a CIa C t sI at CIa s C pressure for a CIa s B ducl
A7 SUGG S ED RANGE OF TES ING
A8 TESTING OF PLANT ITEMS Items of inline pJant (eg Fig 106 to 115) will not normaUy be included in an air I akage test The dllctwork contractor may indud such itelllS in tbe te t jf rh quipm ot has a certificate of COnfOlnlity for Ihe pres ure clas
bull High pressure duct bull Medium pre sure ducts bull Low pre sur ducts bull Exposed extract syst ID bull Ceiling void extract
systems bull Secondary ducts from
VAV or fan coil units bull Flexjble duct bull Final connections and
branches to grille and diffusers
100 test See A5 Untested UDt sted
Untested
Untested Untested
Untested
SI
i
DW154 SJecijicafion for Plastics Ductwork
ig 116 Permitted leakage at various pressures
Leakage in litres per second per square metre duct surface area
Vgt
o ltgt 0 ltgt N
ltgt Cgt
0 0 cc
0 0
~
g =
g ~
c 0
J
ltgt 0 I
~ ] tn
ltgt ltgt
In ol
~ 0 ~ 8 ~
~
c ltgt ltgt
~ CJ
~ ~ ~ ~ 8
0shyij
~ ~ ~ t
ltgt ltgt 00
l
~
~ Q
c C
~ rshy
e ltgt
I 1
I Cgt ltgtv
c Co ~
~~ ~ 10
I
0 Cgt
fJshyq 410 ) 1 ltgt
ltgt N
~ shy ltgt ltgt
~ I 1
c
52
DW154 Specificatio for Plastics Ductwork
Example of a completed test sheet Test No
General
Name of job N~ jC43Pt(r2lef Building Repound ~(~~0
Part 1 - Physical details
a Section of duct work to be tested ~(diffPIfff~el1f3rd Floor
b Drawing Number g91~~ c ssure aSSJ L atlOn V~Jl~IRfYgtg~~lPre Cl T Class C
d Test static pressure -(9 raErq~ ~~~~-~~J~~~ ~~ ~~~~ll
Leakaoe factor 9~-tre3$ecMz I OM REFTOTABLE 13)e b bullbullbullbullbullbullbull
f Surface area of duct under test Q~tJJItetre$ CPROMCALCU TIO BELOW)bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull ampampamp bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull
g ]Vlaxi mum permitted leakage -~ (~i~~0 ~~r~~ ~~~l-~-11~ ~~~Q
Part 2 - Test particulars
a Duct static pressure reading 9QFt~q~ ~ middot~~~1 ~~
b Manufacturer and type of liow measuring d vice (-~~~cJ~Y-9Q7EYg c Range of measurement of now measuring device QtP)OQ~(e~~~0I~~~~1~I~ ~~~~~~W~
d Reading of flm measurin o device pmiddot IFROM RIO)ftscag ~
I (DERlVED [ROM CHART SUPPUED WITH RIG US 0 ud)1e Interpreted air flow leakage rate ~(~~~f~~~ (~l~~~~~~~~~~~~~~~~~I
f Duration ~~~~~norn~allY l~ lnil1Ut~~d~~~ it1~ W~ Date of test ~(lITled ut by Wltll s ed by ~ ~
(~lJ MIJLrr) (Si~rrfltJUYJ
Printed Name 1~g0f~ Printed Name ~~Y~9~ and Company 7jl~~~~~( UJd CompanY AB COII$Itallt8
Width and depth or diameter
Periphery ength Area
millimetreS millimetres metre qL1are metre
800 x 750 3100 1755 5440
600 x 650 2500 557 1193
300 x 300 1200 120 144
305 din 958 700 670
250 dia 785 450 353
TOTAL 8000
53
DW154 Specijilarion for Plastics Ductwork
pA XB
Guida ce No es For he ransport Handling and
Storage of uctwork
avoid damage to adjacent duct panels In somc ca es particularly on con acts calling f r repetitive sizes the use of timber jigs and spacers may be justified Where reduced bulk and greater protection are major factor such as consignments for export transporting ductwork in L shape sections may justify the increa ed ite as embly co ts
It is recommended that before a contract is finalised that consideration is given to the subject of site acces material handling and storage as tbcy havgt a strong influence on the cost efficiency of the overall activity of ductwOlk installation
B3 Handling To minilnise th risk of damage duct sections should be clearly identified and deliveries to site should be closely linked to the installation programme so as to avoid accumulation of
B1 Storage and Handling of Ra Material Material should be stored in suitably designed racking out of direct unJight Where possible the e racks should be metal to earth Edges of cut she t may be harp and protective gloves are advised Wearing teel toe-capped boots is recommended Most pIa tic sheet is manufactured with smootb mfaces andor is suppLied with protective coating Care must be taken to prevent accidental lippag of stacked materials Beiuoshy good electrical insulators the movement of stock unless earthed will allow the build up of stati All stock shapes are chemically stable at normal temperature Whil t some raw materials used in their manufacture may themselves pre ent a toxic hazard once incorporated into the lOck bape they no long r constitute such a hazard and no dermatitic bazard are known nor are any
unfiJied ductwork and minimise double handling It is important to recognise that ductwork panels joint and corners arc susceptible to damage and care must be taken wheu band ling such material through a site During handling individual item of duct work may be liable to light cross sectional deformation until thev become an integral pan of a completed ductwork system Whilst this may temporarily detract from its intended appearance thi deformation will not have any detrimental effect on the functionality of the finally a semblecl system Installation of duct work and asociated plant items ill illevitably involve manual handUng The responsibi Iiry of employers and employees to a ses the risk of personal injury during mallual handling operations is et out in the HS E publication L23 Guidance on Manual Handling Regulations 1992
environmental problems expected 84 Site storage
B2 fransport Large capacity vehicles with high-sided open or closed-top bodies are tlle mo t suitable for the transport of dllctwork Careful consideration should be given to the
Adequate floor space IDust be provided within tbe building for the site storage of ductvork Such storage shalt make due allowance for thc stOf(ne of ductwork in stacks such that access ~ egt
between them is of sufficient width to pennil the removal of item without interference to
unloading of transport on sit a not all siJes b n fit from the material handlino- and access facilities that exi [ in a manufacturing workshop such as crane- fork-lifts or loading bay Site handJiog facilities along with
adjoining sta ks Ductvork components should be positioned so a to avoid crushing Ductwork of small panel size may be stored horizontally however care should be exercised to ensure that tack sizes are limited 10 within
ehicular acce s restrictions may itilluence the type and ize of transport to be uWised
engtlls of ductwork should be positioned 0
the tmctural strength of the duct sections to prevent distortion of the lower sections within the stack
as to avoid crushing Lengths Witll projections such as branches and bends i1anges girths damper quadrauL should be loaded so as to
54
DW154 S1tciic(ltioll for Plastics Ductwork
85 Internal cleanliness of new ductwork The site storage of ductwork introduces the important cODsideration of maintaining the internal cleanliness of the ductwork R feren e should be made to HVCA documentshybull DWffM2 Guide to Good Practice - internal
Cleanliness of New Ductwork Installations If the above conditioDs can not be satisfied consideration should be given by tJle designer to amending the specification to include for Po t Installation Cleaning as covered by tJ1C HVCA documentshybull TRJ17 Guide to Good Practic - Cleanliness
of Ventilation Systems
APPE DIXC
Fi e Retardant inishes C1 Improvement in the fire retardancy of plastic
ducts can be achieved to varying degrees and is wholly dependent llPOll the surface coating laminating resin selected and construction specification adopted In some instances smoke emission is coILSidered equaUy with other speci fication requirernen ts of the materials resistance to ignition and bumjng It is therefore important for design rs to establ ish the clients and officers detailed requirements and not rely on a tbird party interpretation of fire resisting or fire retardant Where possible the specification should refer dir etly to compliance with a British or European Standard identifying the specific sections applicable There are various types of resin and mat rcLnforcements that can achieve a Class 1 surface spread of flame ratin o when tested according to BS476 Part 7 (1987) This test puts materials illto Class I - 4 in descending order of perfoDllance according to the rat and extent of flame spread over their surfac under standard beating conditions Materials should also be tested for flre propagarion to BS476 Part 6 (1989) Tbi tesr measures the amount and rate of heat evolved by the material when subjected to standard heating
conditions Test results are given as an index of Perfonnance (i) whicb is based on three sub indices (iJ (i1) (h) The higher the value of the Index of Performance (i) the greater is the material s contribution to fire growth The higher the value of the sub-index 0) rhe greater the ease of ignition aod flame spread The highest product performance classification as defined in Approved Document B of the Building Regulations is Class O This is acLlieved if a material surface of a composite ploduct i~ either a) composed throughout of materials of
limited combustibility or b) a Class I material which has a tlre
propagation index (i) of not more than 12 and sub-index (i l ) of nor more than 6
01 J Class 0 is not a cla$sif1cation identified in any British Standard test
There are resin system reported to be classified to Class O when tested to BS476 Pcl1S 6 and 7 however designers need to ensure that such sysrems can be applied to their proposed design In propriety resinmat system available the fabrication techniques and COITect application are critical to the integrity of the reinforcing and clas ificatiol1 For example in some systems the u e of a non-fire retardant gelcont on a fire retardant substrate would reduce the classification For further information see HVCA publication DW144 Appendix D
55
DW154 SplCijiClIliol1 for Plastics Ductwork
x Guidance otes For nspectmiddoton Servicing a d
Clean-ng Access Openings
D1 GE ERAL This appendix highlight in ummary fOI111
the acce considerations that hould be made by the design r iD terms of inspection servicing and cleaning Having considered the seop and the design of the dUCI work system relative to the guidelines outlined below the designer should clearly indicate which levels of acces should be incorporated into the manufacture of a new duct work system (See Table 14 and Note I b low it
D2 DESIGN CONSIDERATIONS
D21 In ptction and servicing requireshyments are set out in Section 15 of Lhis specification
D22 Cleaning requirements are set out in the HVCA pubUcation TRl7 Guide to Good Practice Clean Lines of Ventilation Systems and the guide tates The precise location ize and
type of access would be dependent on the type of ductwork cleaning inspection and te ting metbods to b adopted Care protection and standards of cleanliness prior LO cOlllmisionin o
are set out in th AV A publication DWITM2 Guide to Good Practice Internal Cleanliness of New Ductwork Installations and th guide state Wh re specific limits of cleanliness are required ductwork sball be cleaned after installation by a spcialist cleaning contractor It will b in the interests of tht desioner botb financially and practically to cunsider employing a specialist c1eauing contractor at tbe
outset of a contract to internally clean newly installed ductwork prior to bandover This approach would reali e the following benefit shyi) Tb actual numb r of cleaning
access panels could be detennined to suit the method of cleaning to be adopted (This may be 1 s than the maximum requiremen listed under Lev 13 of Table 14)
ii) Clear directions could b given to the ductwork contractor as to tJle size and location of cleaning access panels that are required to be fitted during the mauushyfaclunng pro s
iii) The specialist cleaning operation prior to commi ioning vould enable the cleaning contractor to verify the practical acee requirement for the future cleaning operation associated -vitb a regular maintenance programme
iv) A specialist cleaning operation prior to commissioning would allow the designer to omit from the speeilicatiolJ the DWrrM2 requirem nt for factory sealing protection wipe downs and capping-off
v) Specialist Ieall ill 0 to the measurable standard defin d in TR17 will allow an objective definition of cleanline to be achieved
Car ful consideration must be gIven by the designer to the practl aJ problems associated witb the manufacture and fitting of suitably si Led access panel on small cross section duct and on the circular faces of rouod and flat oval ducts in particular
D23 Special con ideration must be given by the de igner to the practical problems associated with gaining personnel access to heavily congested ceiling areas and multi-la red du twork systems This approach would avoid
56
DW154 Spfciication for Plastics Ductwork
the possibility of access panels being D3 ACCESS 0 IN-LINE EQUIPMENT incorporated into a ductwork system at the This appendix unly covers acc il1spection manufacturing stage that were later found in through the ductwork body adjacent to an item practice to be inaccessible for either ervicing of in-line equipment and not openings in the or cleaning activities equipment itself
able 14 Acce requirements for inspection servicing and cleaning
HVCA PUBLICATIO REFE NeE (uidtgt 10 Gund Prartict
Adjace t OW144 Cleanliness orVcnlillltio S~lcr~ fRjJ7
in-line LeyeJ 1 Level 2 Level 3 ite sequipment pcdionSen lcin~ Section d C1eaniJl( SUn(O)lnspc lion Palle ltk~m_n
2011 (minimum OiL Jubje-ct to duct ~zel (ft~ -Panels
Control Da pcrs One (inspection) 203 One 300 mm x 200 mm Both sid Fire Dampers One (sCTjdJl~) 20211 One 300 0101 x 200 mm One side HeatingCooling Coils One (inspedion) 20213 One 300 mm x 200 mm (lIpstream) Both sides Attenuators (rectangular) None required One 300 mm x 200 mm (downstream) Both sides Attenuators (circular) one retluired One 300 mm x 200 mm (downstream) One side Filter Sections One (inspection) 20212 one required Uoth sides Air Turn Vanes None requjred None required Both sides Changes of Direction None required one required One side In-Duct FansDevices One (inspection) 20213 None required Both sides l
1 In the absence of any indication by the designer only Level ) access will be jncorporated into a new ductwork system
2 Tbe panel izes associated with Lev lis I and 3 acee s ar e middottablished by reference to Section 20 of DW144 and Section 2 ofTRll7 respectively
57
DW154 Speclfifatio for Plastics Ductwork
pA XE
B-bliography Included in this Bibliography are technical pUblications which may be of interest (0 ductwork designers fabricators and erectors and to tho e in the heating ventilatlng air conditioning industries generally nquiric should be made of the relevant organisation at the address quoted Since its publication other addresse contained within 0V154 mav have changed and some pubJicalions may have been superseded
HEATING AND VENTILATING CONTRACTORS ASSOCIATION
4 Palace Court London W2 4JG Telephone 020-7229 2488 Fax 020-7727 9268
Orders fo FlY A Publications Old Matlsion House Eamont Bridge Penrith Cumbria CA 10 2BX (Telephone 01768 864771 Fax 01768 86718) Email hvcapoblicationshvwelfarecouk DWn 44 pe ilicatiun for sheet mctal duclwork (Iow- mediulllshy
and high-pressure) 1998) DWIl4 A practical guide to dUGI ork I akage te ting
(revised 2000) DWII54 Specification for plastic~ duct rk DW171 Guide to good Practice for kitchen venlibtion system DW191 Guide to good pracuce glass fibre ductwoJk DwrrMI Acceptance cheme for new products - Redangolar cro
joint classification Guide to good pra tice - Internal cleanliness of new ductwork installations Guide to good practice for the design for the Installation of lire and smoke uampers
J 1Other puhlications
HampV safely guide 5th edition JS2 Tool box talks JS5 Weldlng Safety booklet JSI9 afety facts bo klet Fact sheets 1-24 2nd edition JS2J COSHH manual volume 1 Advice on compliance with the
regulations 1521A CO I-rH manual volume 2 Asses mcnt h ets JS23 Ri k management manual TR3 BrazinltT and bronze welding of copper pipework cUld sheet
(I 976) TR5 Welding of carbon steel pipework (1980)
TR6 Guide to Good Practice for Site Pre sure Testing of Pipework (19 0) Guide to good practice cleanliness of ventilation Ylem
CHARTERED IN TITUTlO OF BUILDING SERVICES E G EERS Delta House 222 Balham High Road London SW12 9BS rTelephone 020-8675 5211 Fax 020-8675 5449) CIBSE Guide Volume A Design Data Volume B In tallatiol1 and quipment Data Volume C Reference Data
CommlssioniJIg Codes These Codes eover the preliminary checkS eUing to work and regulation of vanous catcgories 0 plan The Codes give a guide to design implications Series A Air Distnbution Systems Series B Boiler Plant
ri s C Automatic Conlrol ystems Cr1es R Refrigerating Sy terns
Sene iN Water Distribution Systems
Technkal Memonllda TM 4 Design Notes for the Middle East TM bull Design otes for Ductwork TM 13 Minimi iog lhc Risk of egiounaires Disease
Research Reports RROI95 Ventilation system hygiene - A review of published
infomlatioo on lhe occurrence and ffects of Olltamination Rl~02J95 Air-to-air heal rec v ry RR0395 rnfluen e of HV C on smoke detectors
ATlONAL ENI [ERING SPECIFICATION LfMITED Southgatc hamber 3739 Southgate Street Winchester S023 9EH (Telephone 01962 842058 Fax 01962 R(8982) BUfLDING S RVICES RESEARCH AND [ ORMATION ASSOCIATIO Old Bracknell Lane West Bracknell Berkshire RG 12 4AH (Telephone Brackl1eU (01344) 426511 Fax 01344 487 -7 )
Application Guides AGln4 De tglJing Vana~le Volume middotylans for KOOnl
iir Movement AG1I91 Commissioning of V Sylcms in Buildings 11 6194 Fire Dampers
B) 94 cntiJalion or KitcneTls
AG389 The Commls ionin of Air Systems In Buildmgs AH2192 Commissioning of Bern - A ~ode of Practice TN2417 I Fire Dampec il) Ventilating Ducl
BEATING VENTILATING A AIR CONDITION G MA UFACTURERS ASSOCIATIO (HEVAC) HEVAC Henley Road Medmenham Marlow Buck SU 2ER (Telephone 01491 578674 ox 01491 575024 Emoimiddot infofetacouk)
Publicatjons Air Diffusion Guide Guide to Air Handling Unit Leakage Testing Guide to Good Practice Air Handling Unit Real Room Acoustic ~ st Procedure Specification for the ertiiicatioll ofAir Filters Method of Test for Water Rejection PerfOnTlatce of Louvrcs Subjected 1(1
Simulated Rainfall Test Procedure for Acoustic Loo cs Specification 10 Floor GrilJes - Types Performan e and Method ofTest Specification for the Determination of the Collection Efficiency of SilJ1d
Trap Louvre Domestic Mechwlical Vclltllalion Systems with Heal Recovery Fan Application Guid
~an and Ouctwork Installation Guide Guide to Fan Noise and Vibration
pecification of Requirements for JallJral Smoke and Heal Exhausl Ventilators
pecification for Powered Smoke and Heat Exhaust Ventilators
Specification of Requirements for Smoke Curtains Design Gujue of Smoke Ventilation for Single Storey Lodustrilll Building~
Including those with Mezzanine Floor and IIi Racked Storage Warehou es - Issue 3
Guidance for the Design of Smoke entilation YSlem for Covered and Undergrollnd Car Parks - lssue 1
Application of SOloke Control Equipment and Syst m Guid to Good Practice - Isue J
58
DW154 Sp(C~tiifitiol for Plastics Ductwork
BRITISH STANDARDS INSTIT TION Sales Department 101 P ntooviLle Road London NI 9ND (felephone 020-78 1 78801)
CP 413 1973 Ducts for building ervices
SS 476 Fire tes on building matenals and lruc(ure
Part 4 19 4 Non-combustibility lest or materials
Part 6 I Fire propagation lest for materials
Part 7 1993 Surface spread of tlarnJ tesls for materia
Part 20 1987 Fir resistance of elements of construction
Part 21 1987 Fire r sistlUlce of loadbeanng elements of construction
Part 22 1987 Fhe istallceofllon-loadbearing elemcllts ofconsttuclion Part 23 1987 Contribution of componcnts to the fire resistance 0 a
structure
Part 24t987 Fire resi lance of wl1lilation ductl
SS 5588 nan 919 0 Fire Precautions III thc desIgn and OOSlnJ lion of buildings
S 729 1971 Hot dip galvanized oatiugs (or irOIl aod stcel articles
BS 1449 Steel plate sheet and Irip
Pan 11991 Carbon steel plate heel and strip Part 2 1983 Stainless steel plate sheer and strip
and
B middotENJOI49-2 996 BSEN 10149- 1991)
BSEN 10131 1992
BSEN22063 Sprayed metal coarings 1994 Protection of iron and steel by aluminium and zinc against
atmospheric cOlosion Irotectiotl of iron and ste I against corro ion and oxishydation at elevared temperatures
BS 353 1981 Glossary of lerms relnting to thermal insulation
BS ISO 1479 Self-tapplngscrewsandmetallicdri c crew
B -lSO 7049
1994
B 4800 1989 Painl colour for building purposes B 4848 l0 rolled structural steel sections
Part4 1972 Equal and unequal angles BS 5422 1990 Specification for the use of therm illuating matcriulS
SS 5720 1979 ode of practice for mechanical veutilating and air C 11shy
dirionin bull in building
l3S PR 12814-1 Bend resting for plasric welds
SS PR 12814-2 Tensile testing for plastic welds
SS PR 13067 Appro altesting for plastic welds
BS PR EN I 100-] Vi ual in pection ofplaslic welds
SHEET METAL AND AIR CONDITIONING CONTR-CTORS NATIONAL ASSOCIATION INC (SMACNA) Headquarters 420 I Lafayeue Center Drive Chanlilly Virginia 2051-1209
Mailing Address pa Box 221230 Cbantilly Virginilt120 153-1230
Telephone (703) 803-2980 Fax (703) 803-3732
Accepted IJJdustry Pl3Gtice for Industrial Duct Constnlelion 197 ) i-rchitecmral Sheet kwl Manual ([993)
Comractors Guide lor Modification 10 ooslruerion Colllraets 1993 Ducted Eleclric Heat Guide for ir Handling Ssrerns (1994)
En~rgy ollservatioD Guidelines (1984) Energy Recovery Equipment yslClllS (199l
Fibrou GIns Duct onS1ntClion Standards (1992)
Fire Smoke amp Radiation Damper In tall Guide for HVA Syst ms (1992) Guide t leel Stack 1(95)
HVA Air Duct Leakage Test Manual (19 ) HVA COlllmissioning lvlanual (1994)
H A Duct Construction Standards-Metal amp Flexible (1995) Addendum 01 (Nov 1997)
HVA Duct Systems Inspection Guide (1989)
HVA ySlems-Application (1986) nVAC ByternS-DLlct D ign (1990)
HVi Systems-Testing Adjusting amp Balancing (1993)
indoor Air Quality Manual (1993) tcheu quipment Fabrication Guidelmes (1990)
Managers Guide for elding (1993)
Rectangular Industrial Duct Cons1TUction Standards (19 0) Round Industrial Duct oustmction Standards (1977)
Sei mic Restraint Manual (1991) (wl Appendix E 1993) SMACNA Ma le Index ()fTechnical Publications (1995) Tbennoplnstic Duct CPY ) Construction Manual 1994)
DEPARTME OF THE ENVIRO MENT (Publications Centre) H Stationery Oflice 5 Nine Elms Lane London SWS 5DR
MampEJ 011972 Electrical in tallat1011 in buildings ( ew Editiou)
IampE 0319 Healing hot and cold wat r steam and gas losla1lations for buildings
M amp - No4 1970 Central heating and hot and cold ~ ateT in tallations for
dwelling
M amp ENo100 1971 Mechanical ventilation for building~
ASSOCIATION FOR SPECIALIST FIRE PROTECTlO As ociation House 235 Ash Road AJdershot Hampshire GUl2 4DD
Telephone OJ25221322 Fax 0 J252 333901
lublicalioos Fire Ratcd and moke Outlet Ducrwork An Industry Guide t Design and InSlalla lioll
HEALTH AND SAFETY EXEC TIVE Rose Court 2 Southwark Bridge London SEl 9HS Telephone 020-7717 6000
TWJ THE WELD G TlTUTE Abington Hall Abington Cambridge CB16AL Telepbone 0 J223 89162
Publication DatJ Oil w~ldll1g of lhermopla lics
59
DW154 wciiwlioll for Plastics Ductwork
A -=--DIX
Factors
Specific gravity shy pp = 091 approx UPVC = 14 approx
Some miscellaneous conversion factors
To convert
Length Inches to millimetres Feet to metres
Multiply by
2540 03048
To convert
Millimetres to inches Metres to feet
vIultiply by
003937 3281
Area Square inches to square millimetres 6452 Square millimetres to square inches 000155 Square feet to square metres 00929 Square metres to square feet 10764
Volume Cubic feet to cubic metres Cubic feet to litres Gallons (UK) to litres
002832 2831 4546
Cubic metres to cubic feet Litres to cubic feet Litres to gallons (UK)
35315 00353
022
Mass Ounces to grams Pounds to kiJograms Tons to tonnes
2835 04536
1016
Grams to ounces Kilograms to pounds Tonnes to tons
003527 2205
09842
Volume flow Cubic feet per minute to cubic Cubic metres per second to cubic
metres per second 0000472 feet per minute 2119 Cubic feet per mIDute to litres Litres per second to cubic feet
per second 04719 per minute 2119
Motion Feet per minute to metres per second 000508 Metres per second to feet per minute 197
Pressure Inches water gauge to millibars 2491 Inches wateJ- gauge to pascals (Pa) 2491 I Pa = I ewton per square metre = 10-2 millibars
60
Heating and Ventilating Contractors Association Esca House 34 Palace Court London W2 4JG
Tel 020 7313 4900
e-mail contact Itvcaorguk web site wwwhvcaorguk
Fax 020 7727 9268
bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull
DW154 SpaiicatiOll for Plastics Ductwork
PART SEVENmiddot APPENDICESmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotAppemiddotndixmiddotmiddotjmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotAmiddotjrieakagefroniductwork middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot49middotmiddotmiddotmiddotmiddotmiddot Appendix 8 Guidance notes for the Transport Handling and Storage of ductwork 54 Appendix C Fire retardant finishes 55 Appendix D Guidance notes for Inspection Servicing and Cleaning access
openings 56 Appendix E Bibliography 58 Appendix F Conversion tables 60
Table LIST OF TABLES _ PART TWO - STANDARDS
1 8Ductwork classification and Air leakage limits PARTTHREE - RECTANGULAR DUCTS
2 Minimum constructional requirements - Rectangular Un-reinforced UPVC and pp 13 3 Fastening centres Rectangular duct flange joints 13
PART FOUR - CIRCULAR DUCTS 4 Standard sizes 16 5 Fastening centres Circular duct Flange joints 17 6 Minimum constructional requirements shy Circular Un-reinforced UPVC 18 7 Minimum constructional requirements - Circular Un-reinforced PPS and PP 18
PART FIVE - HANGERS AND SUPPORTS 8 Hangers and Supports - Rectangular Horizontal Ducts 19 9 Hangers and Supports - Circular Horizontal Ducts 19
PART SIX - GENERAL 10 Minimum constructional reguirements - Rectangular GRP Reinforced ducts 30 11 Minimum constructional requirements - CirCUlar GRP Reinforced ducts 30 12 Standard Abbreviations 47
PART SEVEN - APPENDICES 13 Air leakage rates 50 14 Access requirements for inspection servicing and cleaning 57
LIST OF ILLUSTRATIONS 0 bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull u
Fig PART THREE - RECTANGULAR DUCTS 1-4 Cross joints 14 5-6 Stiffeners 14 7 Tie rod assembly 14 8 Hard and Easy bends 14 9 Turning vanes 15
PART FOUR - CIRCULAR DUCTS 10-12 Cross joints 17 13 Stiffeners 17
PART FIVE - HANGERS AND SUPPORTS 14-16 Support bearers 20 17-18 Vertical ducts supports 20 19-22 Arrangement of bearers and hangers 21
PART srx - GENERAL 23-25 Expansion joints 25 26-28 Flexible connections 26 29-33 GRP reinforced - Cross joints and Stiffeners 31 34 35
Linear Thermal Expansion 34 35
36-77 Typical Design Stress Standard component drawings - Rectangular 33
78-105 Standard component drawings - Circular 40 106-115 Standard component drawings - PlantEquipmentMiscellaneous 46
PART SEVEN - APPENDICES 116 Permitted leakage at various pressures 52
Example of a completed test sheet 53
5
DW154 Specijimrol1 for Plastics Ductwork
ART 1 4
bullbullbullbullbullbullbullbullbull 41
Technical information to be provided by the desmiddotg er to the plastics ductwork cont actor 42
1 INTRODUCTION 11 Thi specificalion relates to the manufa ture
and installation of rectangular and circular 43 ductwork constructed from plastics The selection of construction method is at the discretion of the manufacturer to conform with the performance requirements of the pecified 44 ductwork clas ification Sections 2-4 blow define the information to be provided by the designer
45 2 STANDARDS
21 Pressure classification (Table 1)
22 Leakage classification (Table 1) 46
23 Positive and Negative pressures (Table I)
24 Materials (Parr 2 Section 7)
25 Any special ystem requirements 47
3 COMPONENTS
31 Access and drainage points Number and location of access doors and drainage points
32 Regulating dampers Specification location and mode of opelatioll of all regulating dampers 48
33 Fire stops Stops to meet the requiremen ts of the Authority directly responsible for fire protection 49
34 Flexible joint connections Sp cification and location of any flexible conne tions eg plant or building expansion joint
PARTICULAR REQU REMENTS
Plastics material Type of plastic material from which the ductwork i to be manufactured and detail of ductwork to special requirements not within this specification
Environmental Env ironmental conditi ons inside and sULToundillg tJle ductwork
Airflow Design airflow volume for all mam ducts branches and air tenninals
Pressurevelocities Design air velocities and pressures for all main ducts principal branches and tenninals
External thermalacoustic insolation he extent and type of insulation to be
provided by others should be stated including full specification for application and installation
Spark testing U spark testing is required the designer shall identify land mark in the contract programme for testing to be undertaken ie manufactur installation corrunissionjng
Air leakage testing The extent of any air leakage testing if required While it shall be mandatory for highshypres ure ductwork (a defined in this specification) to be tested for air leakage iu accordance with the procedure set out in DWI43 A Practical Guide to Ductwork Leakage Testin2 no such te tin of Jaw-oro
mediam-pres Llr duct work is requjJmiddoted
Identification Details of colour coding or identification if required For furth r information see HVCA publication DWl44 Appendix B
Solvent~fomes
Details of design criteria used or adopted to avoid the trapping and discharge of liquid solvent fumes or gases
6
~--
DW154 Specificatio1l for Plastics Ductwork
410 Protective finishes (Part 6 Section J9) Detai Is and specification of any protective finishes
411 Fire retardant finishes (Part 6 Section 23) The extent and limits of protection for any fire retardant finishes on plastic ductwork (Specific references must be defined)
412 Controlssensing equipment Details of positions and fixing configuration of all sensors and test points to suit specialist contml and sensing equipment
413 Special supports (Part 5 Section 14) Details of any spanning primary secondary steelwork or special support requirements not specifically covered by Section 14
414 Attachment to building structure (Part 6 Section 20) Specific requirements for the junction of ductwork and associated components to opening hou1d be detailed and specified with the limits of responsibility defined
Tbe design and provision of penetrations and associated framings are outside the scope of this specification
415 Ductwork layout drawing Details of any special requirement$ relating to CAD scales etc It is common practice and cost effective for duclwork manufacturers to utilise their approved ductwork layout drawings as a basis of their manufacturing installation information by adding the necessary details to the same drawin2 Scales of 150 or smaller may preclude tJlis practice therefore larger scales might be more appropriate The final choice of manufacturing installation scales shall be left to the ductwork contractor
416 Other requirements Details of any requirements far the ductwork not in accordance with the provisions of tbis specification including any modified construction required to conform with any requirements cancerning external ductwork (See 53) or to meet the regulations of a local autbority or athcr controlling body
4 7
Clause
Reference to designer In consideration of the foregoing reference is also made to the designer in the following c1ausesshy
Page 52 8 53 8 106 12 1072 12 111 12 131 16 1352 17 136 17 141 19 144 19 145 19 147 20 152 22 161 22 1631 23 1634 23 171 24 173 24 174 24 181 24 182 27 191 27 211 27 222 28 223 2R 231 28 252 31 Appendix A 49 Appendix B 54 Appendix C 55 Appendix D 56
7
DW154 Spaijicllliflll for Plastics Ductwork
PAR 2 54
Standards
5 APPLICATION
51 This specification sets out minimum requirem nts for tbe manufaclure and in-tallation of ductwork for commercial and industrial fume extraction and exhaust 5y terns made from any of th material listed in Seclion 7 and being within the limit of ize andor material Ihickness speci led in Ihe relevant tables Normal ambient operating temperatures are assumed within the pressurevelocil limits and the limits of air leakage for the various pressur classes prescribed in Table 1
52 Thi specill alion is inlended to apply to ductwork handling fume-laden air which are polluted or is otherwise exceptional in respect of temperarure or humidity (including aturated air) for dllctwork wber the external
surface are exposed to a hostile environment The design construction installati n supports and finishes in such case should be giv n special consideration b the de igner in relation to tbe parti [lIar requir ments of each application
6
61
53 TIlis specification is sllitabl for ductwork expo ed to external atffio phere The designer will need to ~ive sp cift details of any special finish constlUction (See eetiar J9)
62
This specification i ba ed on duct operating environments of not less than - 100e and for
PVC (non GRP reinforced) nor exceeding 40degC UPVC reinforced wilh GRP not exceedin cr
600 e PPS and PP not exceeding 60deg FBPP reinforced witb GRP not exceeding 70degC Systems required to operate at temperatur outside those d tailed above aJthough outside of Ih scop of Ll)is specification are Dot precluded but the ductwork hould be designed from fi rst principle Ilaving regard for the physical mechanical and chemical properties of the material It mu~t be noted that the cOlTosive re i tance of all the above m terials will decrea e at temperatures approaching 5deg to looe below the parent materiaL beat distonion point Further guidance on temperatup effect is provided in Fig 34 Linear Tbennal
xpansion and Fig 35 Typical 0 ign Stres es for VC and PP
DUCTWORK CLASSIFICATION AND A R LEAKAGE
Classification and air leakage limits Duc work la sification and air leakage limitmiddot are eL out in Table 1
Compatibility with CEN The leakage fa tor u ed in able 1 for Classes A Band C ~u-e the ame as those for the cIa e similarly de ignated in th E Document Pr E 12237Pr L507
Table bullbull uctwork Class icati nand ir Leakage Limits (Reproduced from DWI144j
Ducl pressure class
1
Low-pressure -Medium-pressure -High-pressure
-I
I Class A Class B
Class C
Static pr sure limil Air I akage LimitMaximum air
litres per ltccnno per quarevelocity
Positive Negalive metre of duct surface areu
2 4 5 ~ -Pa Pa
f-m1s
0027 X pors500 10500 --1000 0009 x po6~750 20
0003 x pO652000 750 40
Where p is he differential pressure in pascals
Nole Tllls specification DWl54 onJy covers construction up to 1500 Pa
8
- - shy -~----
- shy
DW154 SpeciiCfllioll for Plastics Ductwork
63 Leakage at various pressures and other 110 mm to 600 mm dia (Dimensional rela tionships tolerances to DIN 8062) Applying the limits specified In Table 1 Appendix A (Table 13) sets out the permitted 74 PPS (Forms aailable) leakage at each of a serie of pressures up tu a maximum for each class Incloded in that 741 Extmded sheet in thickness 3 mm to Appendix is a graphical presentation of the 12 mm (Dimensional tolerance to pre urelleakage relationship DIN 53479)
DWl143 A Practical Guide to Ductwork 742 V series tube in sizes 1] 0 mrn lO 630 Leakage Testing provides detai Is of the basis mm dia and fittings in size I 10 mm for the leakage limits specified in Table 1 to 400 mm dia (Dimenional
tolerances DIN 53479) 64 Air leakage testing
Air Jeakage testing of low and medium 743 All PPS material used hall be pressure ductwork is not mandatory under compatible and comply with DIN tJlis specification Air kakage testing of high 4102 part B and SS 476 part 7 class pressure ductvork t mandatory under this 4 PPS material should not be used for specification and for details of testing external applications vithout suitable procedure refer LO DW143 A Practical Guide protection (See Part 6 section 19) to Ductwork Leakage Testing
744 It should be noted thal PP is not fully 7 MATERIALS compatible wilh PPS
71 Application 75 FBPP (Forms aailable) This specification applies to ductwork constructed from materials as defined below 7 51 Sheet in thickness 3 mm to 9 mm or equal Minimum material thickness is to be taken a a nominal thickness as Tables 267 7 52 Continuous roll form in thickness 2 10 amp 11 AJJ UPVC materials ued shall be mm to 4 mm low flammability selfextinguishing compatible and UV stable with pigment colour to RAL 7 53 This particular material is specifically 7011 and DIN 4802 B 1 designed to be externally reinforced
with GRP (See Section 24) 72 Types
The materials covered by thi specification are 76 UPVCGRP abbreviated herein as foIlowsshy This is a form of composite lamjnate used (UPVC) Unplasticised polyvinyl chloride where improved mechanical trengtb UV (PPS) Self eXlioguihing polypropylene stabilisatiolJ or fire retardence is required (PP) Polypropylene (GRP) Gla s reinforced plastic 77 UPVCIFOAMJGRP (FOAM) Rigid polyurethane self FBPPFOAMfGRP
extinguiShing foam This is a form of composite laminate used (FBPP) Fabric backed polypropylene sheet where insulation andor support is required for
special applications 73 UPVC (Forms available)
8 DUCTWORK CONSTRUCTION 731 Extruded sheet in thickness 3 mm to AND JOINT SEALING
12 mm (Dimensional tolerances to DIN 7748) 81 Ductwork construction
The election of longitudillal cross joint and 732 V series tube in sizes 110 mm to stiffener types within the criteria laid dOT1 in
1AOO mm dia and fittings in siz~ Part 3 amp 4 shall be used as a minimum standard
9
DW154 Spet((icatioll for Plastics Ductwork
82 Joint sealing and sealants 8226 The joint mu t be held in po ition ror at leamiddott 5
821 General minutes A jig should be The integrity of the ductwork used jf nece-ltsary to ensure depends on the successful applicatioll that no twisting force i of tbe conemiddot t jointing metbod appl ied to th joint during
the period 822 Solvent cementing
Solvent cementing a atisfactory 8227 Once made the joint method of jointing circular UPVC should not be exposed to socket anu spigot or leeve joints a undue force for eight certain solvent based cement horn shy hour Tb full strength of geneously bond the PVC surface the jOjJlt is not achieved in providing uitabl joints Solvent less than twenty-four cementing i not practicable with PP hours because of its hioh resi tanc to solvents The procedure recommended OTE SOLVENT CEMENT JOINTING by the cement manufacnJrer should METHODS ARE TOT RECOMshybe followed but the following points ME DED FOR RECTANGULAR are important DUCT SECTIONS
[N ALL CASES S ALA MATshy8221 Clearance between ocket ERlALS MUST BE APPLIED
and spigot must be STRICTLY IN ACCORDA CE minimal because of the WITH THE MANUFACTUR ~RS
lirnited gap filling propshy 11 STRUCTIO SAD OSHH ertie of the cement ASSESSMENT
8222 Inside edges of sockets and 823 Hot air welding utside edge of spigot VC and pp a be welded by
shouJd be lightly chamshy Llsing the hot ga Ifil1er rod meUlOd fered ltmd thoroughly cleaned described helow
8223 Mating urfaces should be 8231 The welding gas can be cleaned using a proprietary nitrooen or compressed air solvent cleaner to remove and shltlll b fIltered free grease and slightly etch the from suspended water oil surface vapour and particulate
matter 8224 The cement should be
applied a quickly a 8232 The filler rods shall be possible to the socket and made from material to r pigot over the full area of compatible with the matshythe mating surface are eriaJ being welded should be taken to avoid the use of excessive 8233 Butt weld joints shall be cement bevelled to an included
angle of 60deg to 90deg and 8225 The posi liolling of the joint where po sibl welds shall
mUSl be achieved immedshy be fully penetrated from iately after the cement i both ide of the work applied aJld surplus cement removed
10
DW154 Specificatiol for Plastics Ductwork
8234 The joint face and the filler rod surfaces must be clean and grease fre and preferably roughened b shyfore welding In particular any deposited filler rod that is charred mu t be scraped away before additional runs are added
8235 The numbers of runs of fi lIer rod shall be sufficient to give a thiekne s of era s section of the veld at least equal to the thiekn s of the sheet
8236 Where high frequency park testing i specified lhi shall be undertaken in accordance with tbe weldshying in tmction handbook
Note A full descriplion of welding method is given in the Welding Institut handboo entitled Data on Welding of Thennoplastic Relevant BS amp CE Standards are prEN 12814-1 amp 2 prE 13067 and prE 13100-1
824 Completion of compo ite laminate joints Following solvent ementing or hot air welding of joints campi tion of any specified external laminate shall
carried out to maintain thebe
825
integrity of the construction (S 8227)
Gaskets These can be fabricated from various materials in the form of a pre-formed roll she t or trip applied between opposing faces of fbnced ross joints It i a visable to select material r commended by th ga ket manufacturer for the pecific appucation intended
PART 3
Rectangula ucts
9 RECTANGULAR DUCT SIZES
91 This specification covers duct size up to a rnLltimum longer ide of I -00 mm Duct size with an a peet ralio greater than 4 I ar not recommended Although they offer no problems of construction they increase friclionaJ resi tance and the pos ibility of Dois
10 CONSTRUCTION
101 General Th minimum constructional requiJement r r UPVC and PPPPS un-reinforced are hown in able 2
102 Longitudinal seams Longitudinal seams should Dot be located at corners or in the underside of the duct
103 Sheet jointing seams Seams shall be joined by continuous filler rod hot air welding or by fl1sion Vi ldiug only other form of jointing are not acceptable
104 Socket and spigot joints Sock t and spigot joints shall be formed by purpoe made double cket pi ces 100 mm long and of the ame thiekne material as the duct welded into position on each standard length of duet forming 50 mm de p sockets prepared and ready for final jointing on site with filler [Od of the ame formulation used for prefabrication (See Table 2)
105 Flanged joints
1051 FJa ges Fabricated flanges shall b con tmeted u ing miniumum of 9 mm thick by 50 nun wide material of matching formulation depending on duel size as hown in Table 2 The flange hall be mounted true and square to the duct surface and w lded on both sides a 103 and Figs 3 4 Alternative con truction Illay be
11
DW154 Spedjicfltiotl for Plastics Ductwork
utilised for attacllment to plant or other equipment
1052 Drillings Drjllings shall be placed to permit clearance to tbe extel11al casing and any reinforcement of tbe ductwork for the application of fastening
1053 Fastenings For nonnaJ application bright zinc plated bolts nuts and vashers hall be Llsed in sizes and pitch centres shown in Tabl 3 Where special conditions prevail consideration of other material finishes such as stainless steel bolpounds nuts and washers may be used In all cases gasket materials as Section 825 shaLL be used
106 Expansion joints Wher the configuration of the ductwork does not provide for movement due to temperature change or where such movement is restricted by branches or attachmenL expansion joints should be specified by the designer (See Section 18 FlexibleExpansion joint connections)
It is the re ponsibilir-y of the designer to identify the positions of any necessary expansion joints hased upon design param ters for the individual systems (See Figs 23 to 25 34 amp 35)
Design ote xamples of expansion joints shown in Figs 23 to 25 are not suitable for movement exceeding 30 mm
107 StilJeners
1071 External stiffeners Shall be fitted as specified in Tables 2 amp 10 and Figs 5 amp 6
1072 I temal stiffeners The u e of internal stiffening or bracing shall be acceptable iJ deemed necesary and approved by the designer (See Fig 7)
11 FITTINGS
111 Standardisation of fiuings The terminology and descriptions of rectangular duct fittings a et out in Section 25 are recommended for adoption as standard practice to provide common terms of reference for desi crners quantity surveyor and ductwork contractors and for those using computer in ductwork design and fabrication
Bend are designated as hard or easy and the e terms as used herein have the folJowin o
meanings
Hard signifies rotation in the plane of tb longer side of the cross ection
Easy signiiies rotation in the plane of the shorter side of the cros section
An example iIlu trating these term ] given in Fig 8
Fitting are fabricated by cutting and welding sheet
112 Stiffeners Shall be as 107 and Tables 2 amp 10
113 Splitters Shall be as shown in Fig 41 and welded as 1003
114 ruing vanes Where square bends are required turning vanes as shown in Fig 9 hall be fitted
115 Branches When fitting branch ducts to a main duct care should be taken to ensure that the rigidity- of the duct panel is maintained in terms of tbe sti ffenillg criteria
116 Change shapes Where a change bape is necessary to acconUllOdate the duct and the cross- ectional area is to be maintained the slope haU not exceed 225deg 011 any side (See Figs 52 to 56) Where a change in shape includes a local reduction in duct cras - ectionaJ area the slope should not exceed ISO on any side and tbe reduction in area should not exceed 20 Where tceper angles are necessary due to ile
12
DW154 Spec([icatirJ1l for Plastics Ductwork
restucllOn splitters shall be provided Taper Transformation pieces from circular 10 square pieces reducers and transformation piec s or rectangular shall be made as long a shall be manufactured from the tbickl1 s of p sible and uJe angl ball be uot mor than material specified for the larger size ducl 225 (Fig 55)
loon Pa 1500 Pa
2 3 4 5 6 mm mm mm mm
3 socket amp spigot - - -or tlanged
as Figs 1 2 3 401 to 600 45 flanged 50 x 9 flat 1200 800
50 x 9 flat welded both sides a Fig 3 as Fig 5
601 to 1000 45 flnged 50 x 9 flat 800 600 50 x 9 flat welded both sides as Fig 3 as Fig 5
1001 to 1500 6 anged 75 x 9 flat 600 600 75 x 9 flat welded botb sides as Fig 3 as FieJ 5
or or 70 x 70 x 9 angle 50 x 50 x 5 angle
as Fig 4 welded both sides as Fig 6
N t For constructional operating temp rature limits refer to Part 2 Clause 54
Longer Pitch Bolt Size
Side max 2
mm 1m mm Up to 400 100 8 with washers 401-600 tOO 10 with washers
601middot1000 100 10 with wash rs 1001-1500 100 10 with oycrsized
washer
13
Table 2 inimum con tructional requi ments - rectangUlar nmiddotreinforce UPVC and pp
Joints Sliffeners Maximum spacinOLonger Side MillirnUlll She t between
Thickness Joint~S(iffi ners
mm Up to 400
DW154 SpedflCiltion for Plastics Ductwork
Cross joint - recta gular ducts
Fig 1 Socket and spigot joint (UPVC and PP)
Conlinuou weld joint on sile onlinuou- wcld
CT~r~T2
Fig 3 Flange joint (UPVC and PP)
ontinuou weld
Fig 2 Socket and spigot joint (UPVC only)
Fig 4 Flange joint (UPVC and PP)
S iffeners - rectangular ducts
Fig 5 Flat Fig6 Angle
Oatim wo]
Fig8 Bends - examples of hardTie rod assembly and easy
Hard
Fig7 With spacers Easy
4
DW154 Speci(uariml for Plastics Ductwork
Fig 9 Turning Vanes
HOWl G TYl AL EXAMPLE OF FOCI G
15
Ma vane length shy 615 mm
Example ofbraemg when V1IIle length exeeed max pennined Ahematively two banks of ncs fixmg the centre rail together at ] 50 mm nrrcs
U~_II---- fixed to dnct wall both CDds
bLEVATION
vane
Maximum distance between centrc oflUming vanes should [Jot exceed 60 mm pitch
DW154 SPCCijicllfiull for Plastics Ductwork
practice to provide common terms ofPA T4 reference for designers quantiry urveyor and
Circular Ducts
12 CIRCULAR DUCT SIZES Th duct sizes [n Table 4 have been selected from the ISO and C standard ranges as the 132 preferreod sizes
Table 4 Circular ducts shystandard extruded tube sizes
133 Extruded tube
ISO Standard Sizes (Nominal Diameter) 11
Wan Wall Thickness Thickness
mm mm mm mm 110 500 4022
I25160 600 50 I25200 630 60
225 25 700 60 13425250 800 63
280 900 70 315
23 23 80
355 1000
25 1250 104 400 32 1400 108 450 35
Note The above sizes are subject to normal manufactl1ring tolerances Other size may be available in varying wall Lhicknesses and subject to test and operational pressure
13 CONSTRue ION
13 General Tllis specification covers duct sizes up to a maximum diameter of 1500 mm The minimum constructional requirements for UPVC amp PPPPS un-reinforced ducts sball be as Tables 6 amp 7
ductwork contractors and tho e using computers in ductwork design and fabrication The requirements for circular duct fittings apply throughout the size ranges covered in this specification
Sheet jointing seams Seams shall be joined either by continuous fLiJer rod hot air welding or by fu ion welding Other forms of jointing are not acceptable
Socket and Sl)igot joints Socket and spigot joints shall be formed by purpose made double socket pieces 100 mm long and of the same thickness material as tJJe duct welded into position on each tandard length of duct forming 50 mm deep sockets prepared and ready for final jointing on ite with PVC adhesive andor fill r rod of the same formulation used for fabrication
Flanged joints
1341 Flanges abricated flanges shall be conshy
structed using minimum of 9 mm thick by 50 mm wide material of matching formulation depending on duct size as shown in Tables 6 amp 7 The flange shall be mounted true and square to the duct surfaces and welded OD both sides a 103 and Fig 12
1342 Drilliogs Drilling ball be placed to permit clearance to the external casing and any reinforcement of the ductwork
1343 Fastenings For normal application bright zinc plated bolts nuts and washers hall
16
For srualler diameters preformed fittings are available otberwise fitting are fabricated from segments of duct or sheet welded together
The terminology and description of circular duct tiltings as set Ollt in Section 25 are recommended for adoption as standard
be used in sizes and pitCh centres shown in Table S Wh re special conditions prevail consideration of other material finishes such as stain le steel bolt nuts and wasbers shall be u ed In all ca cs gasket materials as Seciion 825 shall be USed
DW154 Speciliwriml for Plastics Ductwork
135 Stiffeners
1351 External stiffeners Shall be fitted as specified in Tables 67amp 1 I and Fig 13
1352 Internal stiffeners The use of internal stiffening or bracing hall be acceptable if deemed neces ary and appn ved by the designer
f 36 Expansion joints Where the corrfiguration of the ductwork does not provide for movement due to temperature
Cross joints - circular ducts
change or where such movement is restricted by branches or attachments expansion joints should be fitted (See Section 18 Flexible Expansion joint connections)
It is the responsibiLity of the designer to identify the position of any necessary expansion joints based upon design parameters for the individual systems (See Figs 23 24 2534 amp 35)
Design Note Examples of expansion joints shown are not suitable for movement exceeding 30 mm
Fig 10 Socket and spigot joint (UPVC and PP)
ConLinuous weld joim on ite Ontinuous weld
crlr~l
Fig 12 Flange joint (UPVC and PP)
Continllous wcld
boil
Continuous weld or Solvelll cement
Solvelll ccmcnl joim on sile
Fig 11 Socket and spigot joint (UPVC only)
Stiffeners - circular ducts Table 5 Fastening centres shycircular duct flange jointsFig13 Flat
flat conljnlJou~ly welded Diameter Pitch Bolt Size
max
1 2 J 11
1 shy -~
mm mm mm Up to 600 100 8 with washers
601middot1000 100 10 with washers - ---I
1001middot1500 100 10 with oversized washers
1
Minimum offourfixings
17
DW154 Specifiiutiofl for Plastics Ductwork
Table 6 constructional quiremen s - circular unshy inforced U VC
Diameter Minimum Joints Stiffeners Maximum spa ~in r
Sheet between Thickness Jointsl tiffcners
1000 Pa 1500 Pa
1 2 3 4 5 6 UD mm mm mm mm
UO to 600 3 socket amp spigot as Figs 10 11
or fla ged Fig 12
601 to 1000 45 socket amp spigot 50 x 9 flat 2400 2400 as Figs 10 11 welded bo sides
or Oanged as Fig 13 as Fig 12
1001 to 1500 6 Hanged 75 x 9 flat 1200 1200 as Fig 2 welded both ides
as Fig 13
Applies 10 Tables 6 alld 7
Note 1 For constructional operating temperature limit refer to Part 2 luu 54 2 To allow for conicleration or extruded se lions or fabricated component the materia] tllicknes i hawn a nominal
Table 7 Minimu onstrucfional requirements shy circular un-reinforced PPS and
Diameter Minimum Joints Stiffcners Maximum pacio Sheet between
Thickness Join sStiffener 1000 Pa 150n Pa
I 2 3 4 6 mm m m mm
110 to 500 3 socket amp spigot as Fig 10 or flaoged as Fig 12
501 to 750 45 ocket amp spi~ot
as Fi 10 or Uanged as Fig 12
751 to 1000 6 tlanged 50 x 9 Oat UOO 12 0 as Fig 12 welded nth sides
as Fig 13 1 1 to 1250 6 flanged 75 x 9 flat 800shy 800
as Fig 12 welded both sides as Fig 13
1251to~ flangcd 75 x 9 Oat 600 600 as Fig 12 welded both sides
as Fig 13
18
DW154 Sped(icalirm for Plastics Ductwork
PARTS
Hangers an Suppo ts
14 GENERA
141 Supports are an e sentiaJ part of me ductwork system and their supply and in tallation are normally the responsibility of the ductwork contractor The principl s are a I-rvCA publication DWIl44 Part 6 Section 19 and should be read in conjunction with this document
Design Note Designers may pecify specific requirements wbich will supersede guidance given in DW144
142 Rectangular ducts abl 8 give the- minimum requirements for
hanger and supports for un-reinforced ductwork
143 Circular ducts Table 9 gives the minimum requirements for hangers and upports for uD-reinforced ductwork
144 Vertical d cts The design of supports for vertical duct is dictated by site condition and where practical duc hould be upported at 4000 mm interval or where tbey pa s through a floor (but n ver exceeding 4500 mm) see Figs 17 amp J8
145 External ducts Where ducts are external to buildings and may be ubject to wind loading support should be plac d so as to restrain ide tl1ruSt and should allow axial movement as neces ary It is the respon ibility of me de igner to calculate the effect of the particular prevailing condition and to define any special upport requirement
146 Expansion joints Support shall be designed to permit axial movement only and shall e provided on eitl1er ide of expansion joint
I 1shy
I~
mm -Jp to 400
401 to 600 601 to 1000
Table B Hangers and Supports - rectangular horizontal ducts
Hanger Bearer Drop Roll Formed Rod
Long r Side
Cbannel ~-shy ~
---shy
Maximum ~pacing
4 52 3 _ -c Fig 15 - Figs 14 15 16 amp 2J
shy
mmm mmmm 240025 x 25 x 16 40 x 20 x 15 8 240040x20x15 40x 20 x 15 10 240040 x 20 x 1~510 40 x 20 x 15
shy
I
40 x 40 x 15 40 x 40 x 15 24001001 to 1500 I 10
Table 9 Hangers and Supports - circular horizontal ducts
Longer Side Hanoer Split Clips Maximum spacing Drop Roll f-ormed and Wrap-round Rod ~hannel Hang r
2 3 4I Fig 1920 amp 22Fig I
mm mmmm mm mm 25 x 25 x 15 IIp to 355 8 40 x 3- --1-_ 2400
2400
2400 2400
70x 6
40 x 5 SOx 5
40 x 20 x 15 40 x 20 x 15 40 x 40 15
10 10 10
356 to 600 601 to 1000 1001 to 1500
19
DW154 Spccijicutioll for Plastics Ductwork
147 Protection specification Any special coatingpaint Unless otherwise stated all support shall be finishes for protection against hostile manufactured in material as specified in this environments shall be advised by the designer
SUPPORT BEARERS
~ 14 Flg16 Inverted profile
angle I ~lIed steel
channel (alternatives) Fig 15 Profile channel (alternatives)
TYPICmiddotAL VERTICAL DUCT SUPPORTS Flat bar clipStiffening frame Outline ofinsulation stiffening frame or tlanged joint (if applicable) or flanged joint
Stiffening framc or flanged Joint
~~-I ( ee notes 10) I
r--~ -++- ~--4==J===4~---
Fig 17 Vertical rectangular ducts Fig18 Vertical circular ducts
The support bearer which depending on ducti tructural opening size could be either channel or angle section may be ll1ilised in any of the following arrangementsshy
a) To support the underside of a flat bar clip in halves (circular)
b) To support the underidc of either the stiffening frame oftbe flanged joint ofaoy duct section
c) To support either a stiffening frame Or a flanged joint below nsing drop rod srudding
20
DW154 Spediraiml for Plastics Ductwork
Arrangement of bearers and hangers (to be read in conjunction with Table 8 amp 9
wbich list material sizes relative 10 duel izes)
KEY Limits refer to actual duct size - insulation is additional - Typical
attachmentv -Atta hment t strucUlrcI to strucUlrc
I I
I - Flat Bar
I - Drop rod or - utlinc of lllddmg In ulillwn (if
applicable)
Alternative 7 drop rod or rt------------ 1 studdmg q I
I I Rectangular
ii i n 1
Fig 21 Rolled or profiled bearer Limit oncFig 19 Wrap-round hanger Limit 55 DIA
V v Drop rod orAllernaUC 1 1 tudding
drop rod or 1
-- -- 1studding and elded bas 1
I I0 -_
Limit 355 DIA Frg 22 Split clips Limit 1500 DIAFig 20 Flat strap hanger amp split clips
21
DW154 Specification for Plastics Ductwork
6PA deElned in J62 appropriate to the airflow pressure acoustic temperature and corrosion
General
15 ACCESSl SPECTION OPENINGS
151 General These are for inspectionservici ng on 1y
HVCA publication DWIl44 Part 7 - General Section 20 sets out the requirements for access applicable to this specification
152 Cleaningmaintenance Designers shall take specialist advice and then stipulate their requirements for the periodic internal cleaningmaintenance of ductwork and of the consequent need for adequate access for specialist cleaning equipment including the size type and locationfrequency of the actual access openings required
Appendix D sets out guidance notes for the consideration of cleaning access and also makes reference to the HVCA publication TR 17 Guide to Good Practice Cleanliness of Ventilation Systems which covers the su~ject
in greater detail
Note A majority of in tallations in which plastic ductwork is used are considered to have a nigb operational risk potential and provision of access should address this
16 REGULATI G DAMPERS
161 General Balancing dampers and control dampers are elements inserted into an air di tribution system or element of an air distribution sy middottem Balancng dampers permit modification of the air resistance of tbe system and consequently cbanging of the airflow rate Control dampers control tlle airflow rate and may in addition provide low leakage closure of the airflow
The deigner shall specify damper locations taking into consideration that good design practice requires a minimum of five times the diameter or width of the shortest side of uninterrupted flow between plant connections and the damper and select the damper type as
characteristics
1611 Balancing damper To achieve the required distribution of air in the ductwork system at inlets andor outlets for [hi purpose the damper blades are set and Jocked manually in position between fully open and fully closed
1612 Control damper To secure dynamic control of the air now in the ductwork system In thi function the damper will always be power actuated and may require to be modulated between fully open and fully closed and to be capable of taking up any position between these extremes In the fully open position the damper should have a minimum pressure drop In the fully closed position it will not necessarily achieve a complete shut off
162 Types of airflow control dampers Airflow dampers of various types are available for specific purposes as follows
1621 Single - blade dampers Single-blade dampers shall consist of a si ngle pi voted blade cOlllained withjn a casing or section of ductwork The blade shall be adjustable tbmugh a nominal 90 angle by means of a quadrant or similar operating mechanism Where automatic control of the damper is required the spindle shall be extended to enable a powered actllator to be mounted
Single-blade dampers shall have a maximum duct width of 400 nUll and a maximum duct height of 400 mm for rectangular ducts and for circular ducts a maximum diameter of 400 mm
1622 Multi-blade dampers Multi-blade dampers shall consist of a number of pivoted blades contained within a casing The blades shall be
22
DW154 Sedicalirm for Plastics Ductwork
adju table through a nominal 90deg angle simultaneously by intershyconnected linkage or gears connected to a quadrant or similar operating mecbanism Where automatic control of a damper is required a spindle shall be extended to enable a powered achlator to be mounted
There is no restriction on the size of duct in which multi-blade dampers or damper assemblie may be u ed Where dampers are required for blade lengths in excess of 750 mm the blades should be suitably reinforced or supponed 0
individual damper blade should exceed 200 mm in width
1623 Iris dampers Lris dampers shall consist of a nUlllber of radialty interconnected blades which open or close within a casing with duct COlll1cctions The blade shall be simultaneously adjusted by a quadrant or similar operating mechanism
Iris dampers shall be installed as specified by the manufacturers operating and installation instructions where the product is unidirectional with regard to airflow
lris dampers are available for circular ducts only in diameters up to 250 mm (it should be noted that the damper casin i appro)(imately twice the diameter of the duct)
1624 Backdraught dampers Air pressure operated uni-directional rectangular (single or multi-blade) with adapters if fitted to circular ducts
1625 Slide and blast gate dampers A damper [lsed as a shut off facility with an externaJ Lide bousing allowing the blade configuration to be fuJly inserted to fully extended for maxiDlUlll air flow
163 Construction
1631 Materials All products shall be protected against cOHosion as necessary and supplied in a fully finished condition as specified by the designer
1632 Dampers used in low and medium pressure systems The following recommendations apply to dampers forming an integral part of ducrwork with pressure classifications A and B air leakage limits
The dampers shaH be constructed to minimise distortion and prevent jammin in operation Th blade shall be sufficiently rigid to minimise movement when in the locked pOSitiOLl
The blades shall be securely fixed to the operating mechanism All balancing dampers shall have a locking device located on the outsid of the case and shall giv clear indication of the actlwl blad position All penetrations of the duct shall be fitted with suitable seals where necessary
1633 Dampers used in high pressure systems Regulatino- dampers used in duc[work sy tems to pressure cJassification C shall meet tbe construction requireshyments specified in 1631 and 1632 with operating mechanisms out of the air-stream
1634 Proprietary types of damper The use of any specific type of proprietary damper shall be confirmed by the designer In all cases proprietary dampers shall meet the relevant requirements of thi specification
1635 Damper casings Duct damper casings hall be constructed to meet th mllllmum
23
DW154 SpeciJimlioll for Plastics Ductwork
leakage Iim its sp cified for th c1uctwork ystem to which tbey are installed
In order to apply the square metre leakage calculatio as detailed in DW143 A Practical Guide to Ductwork Leakage Testing the reference casing area ball be taken as the perimeter ize of lh damper IDultipli d by the equi alent length of Imetr eg an 800 mm x 400 mm duct damper hall have a surface area for casillg leakag p donnan calculated as follow (2 x 08) + (2 x 04 x I
=24m2 casing area
Other pelforlllance ancl rating test methods for damp f and valves are specified in ISO 5129 and BSIE 1751 and are referenced belm a) Leakage past a closed damper
alve BSIE 1751 b) low ratepre sure requirement
characteri t cs BSIE 1751 c) Operational torque le ring
BSEN 1751 cl) Thermal transfer testing
BSIEN 17 I e) Reg nerated sound power levels
ISO 5129
164 Installation Dampers shall be imaalled in accordance will) any re Ievant ISO EN or British Standard 10 aJ bUT lcling regulation and national code of practice as well as the manufacturers recommendations
17 FIRE DAMPERS AND INT MESCENT SLEEVES
171 General Damper or sleeves arc requiTed on duct y~telll where the designer has -tjpulated the
duct wiU penetrate a fire compartment in the majority of application tbermopla ti ductwork is ugtecl where contamlDated corro ive or otherwise exceptional fumes are concerned it is preferable to use tire damp r which are externalJy mounted ie of the intmnescent operated crush typ
24
72 Fit-e rating The damper assembly should have a fUT
resi tance ratin o equal to that of the fir ban-jer it penetrate and ball be fire tested and rated to the timetemperature curv of B 476 Part 20 and 22
173 Intumescent sleeve At the time of writing this specification qualified test results were available for rectangular dampers and circular dampers up to 55 mm diamet r Manufacture have indicated that they are able t provide speci fications for other size and diameters This infonnation should be confirmed b th de igner Various type are available includino
tho e incorporating ruechanical closing plate and those operated anI by expanded iJllUme c nt media
In all ca es fire damp rs and intnmeBcen leeves shall be supplied and in taUed in
accordance with the manufacturer iJlStructioos and COSHH a essm nt
174 Other types Fire dampers of mious types are availabl for specific purpose~ ee HVCA publication DW144 The de igner should )lot (hat materials for con lt1Jction bould be uitablc for the par1icular application
ALL C SES FIRE DAMPERS AND fNT MESCENT SL _VES SHALL HE S PPLTED AND INSTALLED IN A ORDA CE WITH Tf--IE MANUshyPACTURERS STRUCTTONS AND COSHH ASSESSMENT
18 FLEXIBLEEXPANSION dOINT CONNECTIONS
181 General ploperties Tbe material u ed for flexibleexpan ion iojnt~
mu t meet the design r requirements for temperature air pressllrelfe resistance applicable to pl astic duct sy tem vibration and noi e br akout when incorporated into a jointconnection and shall comply ith lh standard of air-tigbtne specifi cl for the duct work sy tem of which it fOlms part (See Figs 23 24 5 26 27 amp 28 for typical con truclion clelai Is
DW154 SJecilimtol for Plastics Ductwork
Expansion joints
Fig23 Moulded bellows type (rectangular and circular)
Fig24
~F aiblc sleeve
__ liding sleeve
~~~~
Sleeve type (circufar)
Fig 25
AIRFLO
COnlinuou~
weld~
Flexible Iceve
PV A HOWN pp SE BACKING FLATS AS FIG 2
Sliding lee c Co1linuou
weld
Flanged sleeve (rectangular and circular)
25
DW154 Specificatiol for Plastics Ductwork
Flexible con ections
Fig 26 Flexible sleeve with clips (UPVC and PP)
--__ Flexible I eve
I
I
I CODn clioD to plant ~
Band clip
Fig27 Welded flexible sleeve (UPVC only)
Plastic)sed PVC slceve ~-- onll11uo1sly welded
onrreclion to planl ~
Fig28 Flanged flexible connection (UPVC and P )
t sp dally moulded flexible flanged connCClitlll
boil
C)nneclion to plant ~
26
DW154 Specificotiol for Plastics Ductwork
182 LOClt1tion Flexible joint are typicltllly lIsed at building expansion joint and fan inletsoutlets Any others required should be indicated on the de ign drawings Care should be taken to maintain alignment across jointsconnections
183 Length Flexible Jomts shall be kept as short as pra middottieable above a minimum eft ctive length of SO mm In no ca e shall a flexible joint exceed 250 mm in lengtb
184 Connections to rectang a ducts With flanged rectangular connections Ule tlexible material shall be held in pLace with flat pIa tic strip of not less U1an 6 mm thick ltlttached to the flanges using uitabJe fixings The more heavy weight type of fleAible mateLial may also be obtained formed into a channel ection with corners fitted to give a neat air tight j int For pigot connections the Be ible material shall b held in place with flat pIa tic trips n t less than 6 mm thick
t 85 Connections to circular ducts With tlanged circular connections the flexibl material shall be held in place with flat plastic backing strips or proprietary clip bands with screw or toggle fast ners
186 Welded flexible connections (Rectangular and Circular) Where the parent and llexibl material are from imilar ba ed products they can be joined to the duct u ing the welding method described in Section 823
19 PROTECT VE FINISHES
191 nles otherwise stated all ductwork shall be mallllfactured in mat fial as pecified in tbis specification Any special coatingpaint fmishes to be provid d by the duct work contractor sball be advisd by th de igner
20 CONNECTIONS TO BUILDING OPENINGS
201 Fanning and finishing building op nings are not the repoJlsibjlity of the duftw( rk contractor and the note that follow are for guidance purpo e only
2011 Openings in brick block or concrete walls shall have inset frames to provide a suitable means of fixing grille louver masking flanges or the tlanged ends of ductwork The illset frames shall be conslnlcted to maintain the structural int grity of the wlll and where applicable cavities shall be suitably lined
2012 Openin s in dry linino partItIons shall have inset frames a 2011
2013 Openjngs in cladding walls and roofs shall have flaoged leevesframes to provide a suitable means of fixing a 2011
2014 Horizontal and vertical opening xposed to oLltside atmo phere hall
be provided with a suitable weathering fini h at the external face especially where profiled cladding is used
2015 Timber framed op nings are not permitted In fj re compart ment barriers
202 Ductwork connections to building openings hall have a flange of suitable profile to permit practical fixing to the openillg frame In selecting the profile consideration shall be given to Tabl~s 2 and 10 in this specitication relating to duct ize and rating Gasket strip or sealant shall be ltlpplied between the tJaoge and building op ning frame
21 DISCHARGEEXHAUST TERMINAL
21 Tbese shall be vertical open ended and designed to meet and comply with current r gularions on contaminated flue The designer hall ensure that the de ign and perf rmance i suitable for its intended purpose Examples of some typical terminal designs are SbOiD in Figbull 102 10 bull 104 amp 105
27
DW154 SpedjimioTl for Plastics Ductwork
22 THERMAL INSULATION
221 The provision and application of thermal insulation to ductwork is not the responsibility of the ductwork contractor
222 Where ductwork is required to be preshyinsulated the specification should be agreed with tbe designer
223 Where the temperature of the air within the duct promotes condensation on the exterior surface of the duct and cause moisture penetration througb the thermal insulation vapour scaling may be required and in this case the most important requirement is to limit penetration of the seal
The extent of any vapour sealing of ductwork thermal insulation and the support method to be u ed must be clearly pecitled in advance by the designer
224 For detailed information on the thermal insulation of ductwork reference should be made to BS 5422 1990 which covers the specification for thermal insulation materials on pipes ductwork and equipment (in the temperature range -40degC to +700degC) and BS 5970 1992 which is a Code of Practic for Thermal Insulation of Pipework and Equipment (in the temperature range -lOOdegC to +870degC)
23 FIRE RETARDANT FINISHES ON PLAST C DUCTWORK
231 The designer should note tbat ductwork constructed to DW154 has no teted fire rating or information see Appendix C
24 REINFORCEMENT OF DUCTS WITH GRP LAMINATE
241 General Where ductwork is required in larg T izes than are covered by Tables 2 4 6 amp 7 or with the increased strength sometimes necessary for industrial use external reinforcement is normally pwvided by applicatioD of glass fibreresin laminate
GRP systems will bond satisfactorily with standard UPVC sheet but for pp it is
nece sary to use a specially prepared sheet with a glass fabric backing incorporated dOling manufactllfe
The detailed techniques of fabrication using GRP are outside the scope of this speci lcation but the following notes are offered for guidance of ductwork fabricators
242 Materials
2421 Quality The laminate is made up of polyester resin complying with BS 3532 and glass fibre complying with BS 3496 or BS 3749 The nominal ratio of resin to glass fibre should be 7030 by weight
2422 Minimum properties The laminate shall comply with the followiog mini mum pbysical properties
Tensile strength - 70 MNm Tensile modulus - 7 Gl m Flexural strength - 140 M Im Bond strength (hetween laminate and substrate Not less than 7MNm Bmcol hardnes Not le s than manufacturers specification
The GRP reinforcement educe the expansion of the parent material but the resultant stre ses arc well within rhe strength of the bond However the Iinear thermal expansion curve shown in Figs 34 amp 35 will serve as a guide
Surface resistivity electrkal propcltles and acoustical propertie are similar to the relevanl unreinforced materials The fire retarding properties of GRP may be improved by the use of specialisl laminating resin
2423 Forms available GRP Laminate should be built up from the separate materials ie resin aod glass fibre in the form of chopped
I strand mat or spray ravings
28
DW154 Spcification for Plastics Ductwork
2424 Workshop conditions Polyester resuls are sensItIve to lmperature and the workshop hould b maintained at a temperature of herween 20deg and 25degC HiOh relative humidities and damp onditions should be avoided A good rate of air change must be pro icled pJeferably by m chanical ventilation
2425 Storage of materials Resin and urin o agents shouJd be stored in dark cool condirions away from the working area and in confonnit with statutor requireshyments for tJle middottorage of flarmnable liquid Because of Ule Limited torage lif of the unmixed resin and curing a eot mal lials ~hould be ch eked before use to enLlfe that they are within the manufacturer pe ified sh If life (usually ix month from the dm of manufacrure)
Glass fi re should be stored separately und r clean dry conditions
243 Surface preparafon
2431 UPVC To achieve the specified bond strengtll the urface to which the GRP is applied mut first be thoroughly cleaned and then etched either by mechanical means or by the use of a suitable solvent
2432 pp with glass fabric backing To achieve the specified bond middottrength the fabric backing must be thoroughly impregnated Witll resin
244 Mixing the materials for use The re in 1 a three part mix compri lng base I sin hardener and accelerator The manufactur rs pecj[ied proportions are critical and th llUxmg sequenc pecified must be meticulously foUowed
The resin has a very limited life after mixing and before u e It is dependent on the characteri tics and bulk of th resin the alllount of hardener the degree and method of acceleration and the workshop onditions
245 Methods of application
2451 General The mixed resin may be applied by hand or b pray c1epoition The operation must b completed within the gel time of th y tern and tbe laminat fully cOI1olidated to achi v the phy ieal properties pecified
2452 Hand lay-up The duct surface i coated by hand with resin Llsing a brush and a mar of gla fibp orked in until full consolidation achieved Th proc is repeated untiJ th requird thicknes i obtained
2453 Spray depo Won The duct surface is coated WiUl re in by spray gun with the chopped glass roving added through a separate nozzle The full thickne i obtain d in layer with con olidation of each layer by hand roller
246 Construction
2461 General M ini mum COllst ructional requireshyments are pe itied ill Tabl 10 for rectangular and Table 1J for circular dUClS
2462 Joints and stiffeners Fig 29 30 31 32 amp 33 hoI TOSS
joint and tiffener for reinforced UPVC and PBPP duct
247 Worki g practices The fabrication of ductwork pecifiecl ill thi document i not affected by the addition of GRP
29
DW154 SfJcdJicatiOt for Plastics Ductwork
Table 10 Minimum constructional requirements shy
Longer Side Minimum Sheet Thicknes and
GRP Reinforcement
UPVC FBIPP 1 2 3
mm mm mm Up to 1000 3 plus 3 plus
06 kgm2 06 kgOIl GRP GRP
1001 to 2250 45 plus 3 plus 06 kgm 12 kgm
GRP GRP
2251 to 3000 45 plus 6 plus 12 kgm 12 kgm
GRP GRP
Cross Joints
UPVCFBPP 4
mm socket amp spigot
as Fig 30 or flanged as Fig 29
75 x 9 flange welded on both sides as Fig 29
75 x 9 tlange welded on both sides as Fig 29
rectangular GRP reinforced ducts
SlifTeners Maximum Spacing Between
JointsSljffeners UPVCIFBIPP UPVCFBPP
5 6 mm mm
75 x 9 flat 800 as Fig 31 or
50 x 50 x 5 plastic or MS inverted angle as Fig 32
or tormer as Fig 33
75 x 9 flat 600 as Fig 31 or
50 x 50 x 5 plastic or MS inverted angle as Fig 32
or former as Fig 33
75 x 9 flat 600+shyas Fig 31 or 50 x 50 x 5 plastic
or MS inverted angle as Fig 32
or former as Fig 33
Note 1 On rectangular duct up to 400 mm longer side no stiffeners are required 2 Applies to Tables 10 amp I I For COlJstructional operating temperature limits refer to Part 2 clause 5A 3 Tables 10 amp II apply to all pres ure classes up lo ]500 Pa
Table 11
Diameter
1 III
lJp to 1000
1001 to 1750
1751 to 2500
Minimum Sheet Thickness and
GRP Reinforcement
UPVC FBPP 2 3
mm mm 3 plus 3 plus
06 kgm 06 kgm GRP GRP
45 plus 3 plus 06 kgm2 18 kgm
GRP GRP
6 plus 6 plus 12 kglm2 18 kgm1
GRP GRP
Cross Joints
UPVCFBPP 4 III
socket amp spigot as Fig 30 or flaoged as Fig 29
75 x 9 flange welded on both sides as Fig 29
75 x 9 flange welded 00
both sides as Fi 29
inforced ducts
Maximum Spacing Between
JointsStiffeners UPVCIFBPP
6 mm 2400
800
600
Stiffencrs
UPVCFBPP 5
mm 50 x 9 flat as Fig 31
75 x 9 flat as Fig 31 or former as Fig 33 75 x 9 tlat as Fig 31 or t()rmer as Fi 33
ote On extruded tube tip to 600mm diameter no stiffenergt are required
30
DW154 Specificatioll for Plastics Ductwork
G - Cross joints and tiffeners
Fig 29 Flange Joint Fig32 Stiffener shy inverted angle
M artiPfCuQkbdd erttpObri) Wl111 RP tlddtlt
_- GRPloliu] lh~
Fig 30 Socket and spigot joint Fig33 Stiffener shy use of former
Fig 31 Stiffener Flat
I Pv FlPP ~ ~lmJaDUA1) d
OMrlQ rrnall 1( tQlS
25 STANDARD COMPONENT DRAWINGS AND ABBREVIATIONS
251 The illustrations in this section not only highlight where applicable geometric limjtations for the de ign and manufacture or ductwork components but also recommend
standard drawing representation terminology and abbreviations for both duetwork components and some of the more commonly used ancillaryplant items
252 Designers and surveyors should note that bills of quantities should provide a full description
3)
---
v
DW154 Spcc(fim(ml for Plastics Ductwork
Fig 34 Linear Thermal Expansion
u c 0 N ro 0)
b 0)
S
sect0
5 oS cl) 0)
~
on ~ ltl
c U
-30 -20 -10 0 10 20 30 40 50 60 70 80 90 TEMPRATURE C
~ V
-
~~c_ ~
~V
V ~
-7 ~
-- ~V ----
v
-6
+14
+12
+10
+8
+6
+4
+2
0
-2
--4
ig 35 Typical Design Stress tor UPVC and P
7
6
r shy 5E
-c E----0 4t) VJ 0)
ci5 0Jl 3
~
0)
Cl
2
1
o
UPVC
1
000
1
1
pp
- r-- shy r----- shy - t--shy I
__0
-30 -20 -10 0 10 20 30 40 50 60 70 80 90 TEMPERATURE C C
Note Figso 14 amp 35 shaded area refers to GRP reinforced duct
32
DW154 Speciicfltirm for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - REC ~NGULAR
Splilt~r Posilion W-mm pliucr
A B c 40]--QOO 1 W - -
601-1000 1 W4 Wf2 -
1001-1800 3 WI W3 W2
FIG DRAWING DETAfiS
tU]36 ATI Straight Duct with socket and spigol joint
rn [037 Straight Duct with flanged joints
[I []38 Straight Duct with flanged joints
rkJ Short Radius Bend
39 Applies to any augl and for duct up to 400 n11n wide
Minimum (I1m31 radills = 100 mm
Medium Radius Bend (a illustrated)
[kJ Applies to any angle
40 Long Radiu Bend Similar but radius = W
Throlll radius = W2 Applies to any angle
- Short Radius Bend with plitlers
I -shy -shy u co - t lt Li--_ 41 t 0 ~ I I I
~ I
L 1W
Minimum waal radius = 100 mm Splitters not required in bend angle less than 45deg
42 QJ1 Square Bend with turning vanes ij
3
DW154 SP(L~ficatioll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - RECTANGULAR
FIG DRAWl G DETADS
43
~
I v
L L Radius Tee with internal deflectors
44
~ Radiussed Twin Bend
45
Imiddot
er Swept Branch
46 U-
Sqoare Tee with Turning Vanes
47
~ f
Breeches Piece
48 0 y l Piece
34
DW154 Specificatioll for Plastics Ductwork
STANDARD COMPONENT RAWINGS - ECTANGULAR
55
54
51
50
53
52
49
FIG
~MX
RAWlNG
DmiddotMAX
EfjMAX
Minimum throat rndius = 100 mm
Rectangular shy Round Transformatioll
Eccentric Taper 225deg max in either plane Spliller are required for angles greater than 225deg and hould bi eet the angle between any side and duct centreline
DETATLS
Angled Offset
OUset Taper Splitters are required for angle greater than 22 0
and shoold bi eet the angl between any side and dUCI centrelinc
Mitred Offset
Concentrk Taper 2250 max in ither plane SpUtters are required for angle greater than 225deg and should bisect the angle between any side and duel c ntreline
Radiussed Offset
35
DW154 Splcilcuthm for Plastics Ductwork
STANDARD COMPONENT DRAWINGS ~ RECTANGU AR
Branch ducl DimCllsions widlh (W) (A)
urnl mm up lO 200 75
300 100 400 125 600 150
Ocr 600 200
FIG DRAWlNG DETAILS
56 poundplusmni~~ Rectan~lar - Flat Oval Transformation
57 [ Square Branch
58 er Angled Branch
Branch dUCI Dimensions wfdth (W) (A)
[- mm mm59 3shy Shoe Branch Up (0 200 75
--shy AIshy + 300 100
400 125
450 MAX 600 150
Over 600 200
Branch duct DimensIOn
rP X width (W) A)
60 - 1--shy _
~ mm mm
Bell Mouth Branch pto 200 75 300 100 t 400 125
600 150 Over 600 200
0=0 61 -
~ Bell Mouth
- shy T 4-5deg M x
--I 1-shy
TJ
62 X I ] I
Tele-scopic Joint I Illustrated with flangeL
X63
SBD Single Bladed Damper
36
---
DW154 Spedicatioll for Plastics Ductwork
STANDARD OMPONENT DRAWINGS - RECTANGULAR
DRAWING DETAILSFIG
64 on-Return DamperNRD shyshy
shyXbull
Multi-Leaf Damper Can be piggoted or flanged oppo cd or parallel blade
Alternative controls areshy
q p [gtshy
J HD65 Hand
~MD otori ed
PO Pneumalic
L-lt
l 13G 66 Blast Gate DamperX X
FireSmoke DampersSleeves
211r Ratinggtshy----
L_-
---
----
r----
Ir-- shy
IL- _-l
2hr
With i tallation frame
67 41 r Rating
4hr
Smoke damper SD
Intumc cent Sleeve L-d
37
DW154 Specijicutiolt for Plastics Ductwork
FIG
68
69
70
71
STANDARD COMPONET DRAWINGS shy REC ANGULAR
DRAVING DETAILS
gtshy Access Openings
AP 6 Access Panel - Rerno able
w [ ~ Access Door - Hinged
I ~le Inspection Cover
le -I reg -lt
~X X Flexible Connection
~ Drop Cheeked Radiussed Twin Bend
U Drop Cheek Bend
I
72 Air Flow SymbolX
38
DW154 Specifim[ioll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - ECTANGULAR
FIG DRAWING DETAILS
73
74
75
76
77
Q
Q
rp---t
~
V- I Ir---I
JL --11
THE ABOVE DETAILS TYPICAL PLENUM
Air Terminal Plenums
Plenum with side connection
Plenum with top connection
Cover plate with connection
Special plenum with connection
elescopic conn ction in direction of air flow
39
DW154 SpecijicotiOll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG
78
79
80
81
DRAWING
-23~---pound3-(MALE) (FEMAJE)
-t=j--_j(--d-shy
--L
~ THROAT RADI S= D AS T NDARD
e ~
THROAT Rjf)lU = D A MU)
DETAILS
Straight Duct With male and female connectors
Straight Duct With flange joint and slip joint
Bend MouldedIFormed Applies to any angle ego 30deg45deg60deg90deg Medium radius bend as illustrated Long radius similar but throat radius 0
Segmented Bend 90deg four section minjmum as illustrated
Other Angles 60deg = 3 sections 45deg = 3 sections 30deg = 2 sections
I
i
40 shy
DW154 Speciicafinll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG DRAWING DETAlLS
82 Segmented Twin Bend Radius = D2 max
May also be fabricated from tube
83 Equal Tee MouldedIFormed
84 -~ 1in Bend MouldedIFormed
85 Taper Concentric 1 0 as iUu trated Eccentric 30deg iJJcLuded angle
86 Short Taper
41
DW154 SpcUicatol1 for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG DRAWING DETAILS
87 30 max Offset
Angle Branch
Bran h dUCI Dimcnsions dia (D) lA)
Shoe Branch mm mm 88 Cl
Off rectanguJur Up 10 200 75 lOO 10 400 125
- 00 150 Over 600 200
Bl1IllCh duct DimenlOns din (D) (A
~-$a-Conical Branch mm mm
89 Also acceptable with Up 10 200 r
full conical surface 300 10
400 125
END VrE -shy 600 150 Over 600 200
90
m 75
100 12 150 200
mm Up to 200
_ 300 400
600 Over 600
iUtred Branch
Shoe Branch
J-L----U ~ Bell oulh Branch
ENDV1EW
93
92
91
42
DW154 Specificatiol for Plastics Ductwork
STANDARD OMPONENT DRAWINGS - CIRCULAR
FIG
94
DRAW G
I
~ 30deg 090deg
Breeches Piece
DETAILS
95 amp-----~ Blank End
~-----p Multi-Leaf Damper Can be piggolcd or fianged opposed or parallel blade
Alternative controls areshyri=-+- L-T~
I
---
LT~
I r- -
-+1
J HO Hand96
bMD Molori cd
PD Pneumatic
tl-shy bull
Single Bladed Damper 97 ~ saD
on-Return Damper Vertical application only 98 m~D
43
DW154 Sf1tcificatioll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG
99
100
101
102
DRAWING
$ I-
2hr
1 4hr
SD
~v I I
CO TINENTAL COWL
DETAILS
Iris Damper
Fi reS moke Dam persSleeves
2hr Ratillg
With installation frame
4br Rating
Smoke damper
Intumescent Sleeve
Access Openings
Access panel - removable
Access door shy hinged
fnspection cover
Discharge Continental Cowl
44
DW154 Sp(Cii(ltJll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
DRAWINGltIC DETAns
-
I
I
~
I I I High Velocity Discharge Terminal 103 I
I
I I
J I I 1 ~--
Offset Stack Discbarge Terminal 104 1
~ I e --(-
I
N
I
I
I~
I I Vertical Oischarge with Weather Cowl 105 I
--1--1 I
I
GAPI I
RTl AL DISC) lARGE WITH W ATIIER COWL
45
DW154 SpecUicatoll for Plastics Ductwork
STANDARD COMPONE T DRAWINGS - PLA TEQUIPMENTIMISCELLANEOU
FIG DRAWING DETAILS
106 ~~~ Rectangular Attenuator
107 ~- Circular Attenuator
108
~ Beod Attenuator
109 J ~(f) Heating Coil
110 J ftte Cooling Coil
III Jc[ Electric Heating Coil
112 X F
Humidifier
113 [H XX Axial Fan
114 ~fB1famp Noo-standard Ductwork Cross hntchillg (of any separate type) indicates by reference to a key any non DVil54 ductwork system
115 2llIIIIJIIIIIll Flexible Ductwork
46
DW154 SJeCUicll(iol1 for Plastics Ductwork
TABLE 12 - STANDARD ABBREVIAT ONS
ABBREVIATION FLL
AD Acces Door
AFF Axial Flow Fan
AHU Air Handling nit
All Aluminium
AP Acess Panel
AT Attenuator
AV Air enninal Unit
BE 81ank nd
BQ Blast ate Damper
CC Cooling Coil
CF Centrifugal Fan
CTA Cross alk Attenuator
CVU Constant Volume Unit
DP Drain Point
EEC Electric Heating Coil
El Expansion Joint
FAl Fresh Air Inlet
FA From Above
FB From Belo
fBPP Fabric Backed Polypropyl-ne Sheet
Flexle Flexible Connection
lexfD Flexible Du t
C False Ceiling CO an oil Unit
fD Fire Damper
FFL Finished Floor Level
FJ Flanged Joint
FOAM Rigid Polyurethane Self xtinguishing Foam
FOB Flat on Bottom
FOT Flat on Top
GAM Galvanised after ManufacttrJc
GRP Glass Reinforced Plastic
GSS Galvanised Sheet Steel
HC Heating oil
HD and controlled Damper
HH Hand Hole
HL High Level
HVD High Velocity Discharge
IC Inspection Cover
ID lri Damper
IFS Intumescent Fircleevc
47
DW154 Specification for Plastics Ductwork
TABLE 12 - STANDAR ABBREVIATION CONTINUED
ABBREVIATION
IU
L
tv1D
MS
NRD NTS
OBO
OE
PHD
PD
PP
PP
PRD
PVC
RFC
RSC
R
SBO
SO
S1 TST
SSL
TA
TB
TO TJ
TP
TV
TV
OS
UPVC
S
V
VAV
50 RSA
FULL
Induction Unit
Low Level
Motor controlled Damper
Mjld Steel
on Return Damper
at to cale
Opposed Blade Damper
Open End
Parallel Blade Damper
Pneumatic controlled Damper
Polypropylene
Self xtinguishing Polypropylene
Pressure Relief Damper
Polyvinyl Chloride
Rolled Form Chamlel
Rolled Steel Channel
R fUnit
Singl Blade Damper
Smoke Damper
Slip Joint
Stainl t el
tructural Slab Level
To Ab vc
To Blow
Top Down (In Direction of Flow)
Telescopic Joint
Test Point
TU111iog Vane
Top Up (In Direction of Flo )
Voles Otherwise Stated
Unpl3sticisecl Polyvinyl Chloride
Underside
Ultra Violet Light
Variable Air Volume
Rolled Steel Angle (Vith Size)
48
DW154 SJeriiflllioll for Plastics Ductwork
A2 DUCT PRESSUREAPPE DXA Ductwork con truct d to DWIl54 will bebullbullbullbullbullbullbullbullbullbullbullbullbullbull
Air Leakage From Ductwork To be read in conjunction with DW143 A practical guide to Ductwork Leakage Testing
CAUTION As highlighted ill both this docul1lenr and DW14 I lot ellough emphasis can be placed 01 the fact that except for high pressure class C the much more stringent ductwork constructional standard brolght about b the general acceptance of DW154 have irtlally negated the requirement for leakage-testing It is essential lO realise lhat except where it is mandatory this doclllllelll is nOl an endors ~lIlent of the rourine testing of ducts bllt purely a guide to outline the procedures for cononnity with the air leakage limits ill Table l Where the specified methods of assembly and
A3sealing of dlcls are u ed a vi ual inspection wil ordinarily sl~fll e for ver(iatioll of a well engineered and a ceptahfy airtight COl1strucrioll WHERE NOT MANDATORY DUCT LEAKAGE TESTING IS GENERALLY AN UNJUSTIFIED AND SUBSTANTIAL EXPENSE
A1 INTRODUCTION L akage from ducted air distribution systems is an Lmportant consideration in the design and operation of ventilatjon and air conditioning middotystems A ductviork t)ystem tbat ba limited air leakag within defiucd limits wiH cnsUft
that tile design characteristics of the sytem can be maintained It wilJ also ensure that energy and operatLonal cosb are maintained at optimum levels DucLwork constlucted and Ulstalled in accordance with DW154 should minimise a level of air leakage that it) appropriate to tll operating static air pre sur in tile system
A4However it is recouuised that tbe environment in wtJich middotystems are installed is not always conducive to achieving a predictable level of quality in term of system ajr leakage and it is therefore accepted that designer may sometimes require tlle ystem to be tested in part or in total It should be ecogni ed that the testing of duct systems add a ignificant cost to the installation and incur some extra tjm within the programme (Se 47 and 64 re mandatory te-sting)
manufactured to a structural standard that is compatible with the system operating pressure There are three classes of duct con truction to eorre pond with the three pre ure clas meations Class A Lo pressure ducts suita le for a maximum positive operating pressure of 500 Pascal and a maximum negative pressure of -500 Pascals Class B IVledium pressure ductmiddot suitable for a rnaxilnuJJl positive operafjn o pressure of 1000 Pascals and a maxllnum negative pre sure of -750 Pa cal Class C High pre sure ducts suitable for a maximum po ilive operating pressur of 2000 Pa cals and a maximum negativ pres ur of -750 Paltcals
LEAKAGE FROM DUCTWORK Leakao-e front pia tic air ducts occur at the joint~ and is therefore proportional to the total surface area orthe du twork in th system Tb level of leakage i imilarly related to tIle air pres ure in th du t system and whilst there LS n precis formula for calculating the level of air los it i generally accepted that leakage will increase in proportjon to pressure to rbe pOvver of 065 The effect of air leakage from high pressure velocit ductwork is critical tn terms of system perfomlan dege energy consumption and the risk of high frequency noise as ociated with leakage These problems are le critical with medium pressure 10 ity systems but should be con idered Low pres mevelocity ducts present the lowe~t
ri k in tenn of tbe effect of leakage on the operation of the s stern
SYSTEM LEAKAGE LOSS As there i no di ct relatLonship between th volume of air conv yed and the surface area f the ductwork sy tern required to match the building configuratmn it is difficult to express air leakage a a percentage of total air volume Similarly the operating pressure will vary throughollt lh 3 system and a leakage is related to pre me the calculations ar comple However it is generally ac epted tbat in typical good quaJjty systems the leakage from
49
DW154 Specificatioll for Plastics Ductwork
each class of duct llnd r operating condition will be io the region of CIa S A low pressure 6 Clas B medium pres un 3 Clas C high pressure 2
A5 SPECIFYING AIR LEAKAGE TESTING Re peeting both the co -t and programme implications a sociated with te ling du 1 for leakage the designer may for example indicate that a particular system is te ted as follow
a) High pressure ducts - all tested b) Medium pr ssure duets - 10 of the
ductwork shall be s eet d at random and tested
c) Low pre sure - unte ed In any case where a random te t i elected for medium pre sure ductmiddot the followin c1au~e is suggested for inclusion by the de ign r
The designer hall elect at random a maxirnwlI of 10 of the dUCl system to bt tested for air leakage The duct hall be tested af the pressure recommended in Table J3 for the assifi atiol for the ectiol1 of the ductwork that is to be tested The tests shall be carried Ollt as the work proceeds and prior to the application of thermal insulation In the event of test failure of the randomlY selected section the designer shall have The right to select two La1her e tiolls at random for resting Where succes ive failures are identified there shall be a Tight to require rhl COl11raCWr 10 apply remedial attention to the complete ductwork system Th contractor shall provide documented eviden e of the calculalions used to arrive (1
the allowable 10 I for the section to be tested and the client or his agent shall willess and sign the results of the test
able 13 Air leakage rates
Maximum leakage of duct work Static
prcssUft Low-pressure edium-prc-sure I Iigh-prebull me diJfercntial Class A Class B Class C
1 2 J 4 Pa Litres per second per quare metre of surface area 100 054 018 ZOO 084 028 300 110 037 400 132 044 500 153 051 600 058 019 700 064 021 800 069 023 900 075 025
1000 080 027 1100 1200 1300 1400 1500
029 030 032 033 035
1600 1700 1800 1900 2000
036 038 039 040 042
Note Recommend d mean test presures are highlighted iD bold type with the actual selection being left to tll test operator
50
DW154 Sfeeiieaioll for Plastics Ductwork
A9
A10
and air leakage classification for the y em under test
DESIGNERS CALCULATIONS The designer can middotaJculate with reasonable accuracy the predicted total loss from a ystem by
a) Calculating the operatin presure in each ection of the sy tern
b) Calculating the surface area of the ductwork in each correspondin pre lire s ction
c) Calulating the allowabl~ los at the operating pressure for each ection of the system (see table 13 for allowable leakage figures)
VARIABLE PRESSUR S IN SYSTEMS De igner can achieve significant co t saving by matchina operating pressures throughout the system to constmctional standard and appropriate air leakage testing eO the practice of specifying construction tandards for whole duct sy tems based on fan discharge pre sure may incur unnece sary costs on a project For example ome large sy terns ould well be classiC ed for I akage limits as follows
Plant room risers CJas C Main floor distriblltJou CIa B Low pre sure outlets Cla A
A6 SPECIAL CASES There may be ~itLlations on a project where circumstance dictate thal pecial consideration be given to containing air loss s eg a long mn of duclwork may incur a di -proportjonate level of air 10 s In ca es such as thi example the designer can specify an improved tandard of airtighmess ie 80 of alJo~able 10 s for la B Ju ts The designer sbould not specif a CIa C t sI at CIa s C pressure for a CIa s B ducl
A7 SUGG S ED RANGE OF TES ING
A8 TESTING OF PLANT ITEMS Items of inline pJant (eg Fig 106 to 115) will not normaUy be included in an air I akage test The dllctwork contractor may indud such itelllS in tbe te t jf rh quipm ot has a certificate of COnfOlnlity for Ihe pres ure clas
bull High pressure duct bull Medium pre sure ducts bull Low pre sur ducts bull Exposed extract syst ID bull Ceiling void extract
systems bull Secondary ducts from
VAV or fan coil units bull Flexjble duct bull Final connections and
branches to grille and diffusers
100 test See A5 Untested UDt sted
Untested
Untested Untested
Untested
SI
i
DW154 SJecijicafion for Plastics Ductwork
ig 116 Permitted leakage at various pressures
Leakage in litres per second per square metre duct surface area
Vgt
o ltgt 0 ltgt N
ltgt Cgt
0 0 cc
0 0
~
g =
g ~
c 0
J
ltgt 0 I
~ ] tn
ltgt ltgt
In ol
~ 0 ~ 8 ~
~
c ltgt ltgt
~ CJ
~ ~ ~ ~ 8
0shyij
~ ~ ~ t
ltgt ltgt 00
l
~
~ Q
c C
~ rshy
e ltgt
I 1
I Cgt ltgtv
c Co ~
~~ ~ 10
I
0 Cgt
fJshyq 410 ) 1 ltgt
ltgt N
~ shy ltgt ltgt
~ I 1
c
52
DW154 Specificatio for Plastics Ductwork
Example of a completed test sheet Test No
General
Name of job N~ jC43Pt(r2lef Building Repound ~(~~0
Part 1 - Physical details
a Section of duct work to be tested ~(diffPIfff~el1f3rd Floor
b Drawing Number g91~~ c ssure aSSJ L atlOn V~Jl~IRfYgtg~~lPre Cl T Class C
d Test static pressure -(9 raErq~ ~~~~-~~J~~~ ~~ ~~~~ll
Leakaoe factor 9~-tre3$ecMz I OM REFTOTABLE 13)e b bullbullbullbullbullbullbull
f Surface area of duct under test Q~tJJItetre$ CPROMCALCU TIO BELOW)bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull ampampamp bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull
g ]Vlaxi mum permitted leakage -~ (~i~~0 ~~r~~ ~~~l-~-11~ ~~~Q
Part 2 - Test particulars
a Duct static pressure reading 9QFt~q~ ~ middot~~~1 ~~
b Manufacturer and type of liow measuring d vice (-~~~cJ~Y-9Q7EYg c Range of measurement of now measuring device QtP)OQ~(e~~~0I~~~~1~I~ ~~~~~~W~
d Reading of flm measurin o device pmiddot IFROM RIO)ftscag ~
I (DERlVED [ROM CHART SUPPUED WITH RIG US 0 ud)1e Interpreted air flow leakage rate ~(~~~f~~~ (~l~~~~~~~~~~~~~~~~~I
f Duration ~~~~~norn~allY l~ lnil1Ut~~d~~~ it1~ W~ Date of test ~(lITled ut by Wltll s ed by ~ ~
(~lJ MIJLrr) (Si~rrfltJUYJ
Printed Name 1~g0f~ Printed Name ~~Y~9~ and Company 7jl~~~~~( UJd CompanY AB COII$Itallt8
Width and depth or diameter
Periphery ength Area
millimetreS millimetres metre qL1are metre
800 x 750 3100 1755 5440
600 x 650 2500 557 1193
300 x 300 1200 120 144
305 din 958 700 670
250 dia 785 450 353
TOTAL 8000
53
DW154 Specijilarion for Plastics Ductwork
pA XB
Guida ce No es For he ransport Handling and
Storage of uctwork
avoid damage to adjacent duct panels In somc ca es particularly on con acts calling f r repetitive sizes the use of timber jigs and spacers may be justified Where reduced bulk and greater protection are major factor such as consignments for export transporting ductwork in L shape sections may justify the increa ed ite as embly co ts
It is recommended that before a contract is finalised that consideration is given to the subject of site acces material handling and storage as tbcy havgt a strong influence on the cost efficiency of the overall activity of ductwOlk installation
B3 Handling To minilnise th risk of damage duct sections should be clearly identified and deliveries to site should be closely linked to the installation programme so as to avoid accumulation of
B1 Storage and Handling of Ra Material Material should be stored in suitably designed racking out of direct unJight Where possible the e racks should be metal to earth Edges of cut she t may be harp and protective gloves are advised Wearing teel toe-capped boots is recommended Most pIa tic sheet is manufactured with smootb mfaces andor is suppLied with protective coating Care must be taken to prevent accidental lippag of stacked materials Beiuoshy good electrical insulators the movement of stock unless earthed will allow the build up of stati All stock shapes are chemically stable at normal temperature Whil t some raw materials used in their manufacture may themselves pre ent a toxic hazard once incorporated into the lOck bape they no long r constitute such a hazard and no dermatitic bazard are known nor are any
unfiJied ductwork and minimise double handling It is important to recognise that ductwork panels joint and corners arc susceptible to damage and care must be taken wheu band ling such material through a site During handling individual item of duct work may be liable to light cross sectional deformation until thev become an integral pan of a completed ductwork system Whilst this may temporarily detract from its intended appearance thi deformation will not have any detrimental effect on the functionality of the finally a semblecl system Installation of duct work and asociated plant items ill illevitably involve manual handUng The responsibi Iiry of employers and employees to a ses the risk of personal injury during mallual handling operations is et out in the HS E publication L23 Guidance on Manual Handling Regulations 1992
environmental problems expected 84 Site storage
B2 fransport Large capacity vehicles with high-sided open or closed-top bodies are tlle mo t suitable for the transport of dllctwork Careful consideration should be given to the
Adequate floor space IDust be provided within tbe building for the site storage of ductvork Such storage shalt make due allowance for thc stOf(ne of ductwork in stacks such that access ~ egt
between them is of sufficient width to pennil the removal of item without interference to
unloading of transport on sit a not all siJes b n fit from the material handlino- and access facilities that exi [ in a manufacturing workshop such as crane- fork-lifts or loading bay Site handJiog facilities along with
adjoining sta ks Ductvork components should be positioned so a to avoid crushing Ductwork of small panel size may be stored horizontally however care should be exercised to ensure that tack sizes are limited 10 within
ehicular acce s restrictions may itilluence the type and ize of transport to be uWised
engtlls of ductwork should be positioned 0
the tmctural strength of the duct sections to prevent distortion of the lower sections within the stack
as to avoid crushing Lengths Witll projections such as branches and bends i1anges girths damper quadrauL should be loaded so as to
54
DW154 S1tciic(ltioll for Plastics Ductwork
85 Internal cleanliness of new ductwork The site storage of ductwork introduces the important cODsideration of maintaining the internal cleanliness of the ductwork R feren e should be made to HVCA documentshybull DWffM2 Guide to Good Practice - internal
Cleanliness of New Ductwork Installations If the above conditioDs can not be satisfied consideration should be given by tJle designer to amending the specification to include for Po t Installation Cleaning as covered by tJ1C HVCA documentshybull TRJ17 Guide to Good Practic - Cleanliness
of Ventilation Systems
APPE DIXC
Fi e Retardant inishes C1 Improvement in the fire retardancy of plastic
ducts can be achieved to varying degrees and is wholly dependent llPOll the surface coating laminating resin selected and construction specification adopted In some instances smoke emission is coILSidered equaUy with other speci fication requirernen ts of the materials resistance to ignition and bumjng It is therefore important for design rs to establ ish the clients and officers detailed requirements and not rely on a tbird party interpretation of fire resisting or fire retardant Where possible the specification should refer dir etly to compliance with a British or European Standard identifying the specific sections applicable There are various types of resin and mat rcLnforcements that can achieve a Class 1 surface spread of flame ratin o when tested according to BS476 Part 7 (1987) This test puts materials illto Class I - 4 in descending order of perfoDllance according to the rat and extent of flame spread over their surfac under standard beating conditions Materials should also be tested for flre propagarion to BS476 Part 6 (1989) Tbi tesr measures the amount and rate of heat evolved by the material when subjected to standard heating
conditions Test results are given as an index of Perfonnance (i) whicb is based on three sub indices (iJ (i1) (h) The higher the value of the Index of Performance (i) the greater is the material s contribution to fire growth The higher the value of the sub-index 0) rhe greater the ease of ignition aod flame spread The highest product performance classification as defined in Approved Document B of the Building Regulations is Class O This is acLlieved if a material surface of a composite ploduct i~ either a) composed throughout of materials of
limited combustibility or b) a Class I material which has a tlre
propagation index (i) of not more than 12 and sub-index (i l ) of nor more than 6
01 J Class 0 is not a cla$sif1cation identified in any British Standard test
There are resin system reported to be classified to Class O when tested to BS476 Pcl1S 6 and 7 however designers need to ensure that such sysrems can be applied to their proposed design In propriety resinmat system available the fabrication techniques and COITect application are critical to the integrity of the reinforcing and clas ificatiol1 For example in some systems the u e of a non-fire retardant gelcont on a fire retardant substrate would reduce the classification For further information see HVCA publication DW144 Appendix D
55
DW154 SplCijiClIliol1 for Plastics Ductwork
x Guidance otes For nspectmiddoton Servicing a d
Clean-ng Access Openings
D1 GE ERAL This appendix highlight in ummary fOI111
the acce considerations that hould be made by the design r iD terms of inspection servicing and cleaning Having considered the seop and the design of the dUCI work system relative to the guidelines outlined below the designer should clearly indicate which levels of acces should be incorporated into the manufacture of a new duct work system (See Table 14 and Note I b low it
D2 DESIGN CONSIDERATIONS
D21 In ptction and servicing requireshyments are set out in Section 15 of Lhis specification
D22 Cleaning requirements are set out in the HVCA pubUcation TRl7 Guide to Good Practice Clean Lines of Ventilation Systems and the guide tates The precise location ize and
type of access would be dependent on the type of ductwork cleaning inspection and te ting metbods to b adopted Care protection and standards of cleanliness prior LO cOlllmisionin o
are set out in th AV A publication DWITM2 Guide to Good Practice Internal Cleanliness of New Ductwork Installations and th guide state Wh re specific limits of cleanliness are required ductwork sball be cleaned after installation by a spcialist cleaning contractor It will b in the interests of tht desioner botb financially and practically to cunsider employing a specialist c1eauing contractor at tbe
outset of a contract to internally clean newly installed ductwork prior to bandover This approach would reali e the following benefit shyi) Tb actual numb r of cleaning
access panels could be detennined to suit the method of cleaning to be adopted (This may be 1 s than the maximum requiremen listed under Lev 13 of Table 14)
ii) Clear directions could b given to the ductwork contractor as to tJle size and location of cleaning access panels that are required to be fitted during the mauushyfaclunng pro s
iii) The specialist cleaning operation prior to commi ioning vould enable the cleaning contractor to verify the practical acee requirement for the future cleaning operation associated -vitb a regular maintenance programme
iv) A specialist cleaning operation prior to commissioning would allow the designer to omit from the speeilicatiolJ the DWrrM2 requirem nt for factory sealing protection wipe downs and capping-off
v) Specialist Ieall ill 0 to the measurable standard defin d in TR17 will allow an objective definition of cleanline to be achieved
Car ful consideration must be gIven by the designer to the practl aJ problems associated witb the manufacture and fitting of suitably si Led access panel on small cross section duct and on the circular faces of rouod and flat oval ducts in particular
D23 Special con ideration must be given by the de igner to the practical problems associated with gaining personnel access to heavily congested ceiling areas and multi-la red du twork systems This approach would avoid
56
DW154 Spfciication for Plastics Ductwork
the possibility of access panels being D3 ACCESS 0 IN-LINE EQUIPMENT incorporated into a ductwork system at the This appendix unly covers acc il1spection manufacturing stage that were later found in through the ductwork body adjacent to an item practice to be inaccessible for either ervicing of in-line equipment and not openings in the or cleaning activities equipment itself
able 14 Acce requirements for inspection servicing and cleaning
HVCA PUBLICATIO REFE NeE (uidtgt 10 Gund Prartict
Adjace t OW144 Cleanliness orVcnlillltio S~lcr~ fRjJ7
in-line LeyeJ 1 Level 2 Level 3 ite sequipment pcdionSen lcin~ Section d C1eaniJl( SUn(O)lnspc lion Palle ltk~m_n
2011 (minimum OiL Jubje-ct to duct ~zel (ft~ -Panels
Control Da pcrs One (inspection) 203 One 300 mm x 200 mm Both sid Fire Dampers One (sCTjdJl~) 20211 One 300 0101 x 200 mm One side HeatingCooling Coils One (inspedion) 20213 One 300 mm x 200 mm (lIpstream) Both sides Attenuators (rectangular) None required One 300 mm x 200 mm (downstream) Both sides Attenuators (circular) one retluired One 300 mm x 200 mm (downstream) One side Filter Sections One (inspection) 20212 one required Uoth sides Air Turn Vanes None requjred None required Both sides Changes of Direction None required one required One side In-Duct FansDevices One (inspection) 20213 None required Both sides l
1 In the absence of any indication by the designer only Level ) access will be jncorporated into a new ductwork system
2 Tbe panel izes associated with Lev lis I and 3 acee s ar e middottablished by reference to Section 20 of DW144 and Section 2 ofTRll7 respectively
57
DW154 Speclfifatio for Plastics Ductwork
pA XE
B-bliography Included in this Bibliography are technical pUblications which may be of interest (0 ductwork designers fabricators and erectors and to tho e in the heating ventilatlng air conditioning industries generally nquiric should be made of the relevant organisation at the address quoted Since its publication other addresse contained within 0V154 mav have changed and some pubJicalions may have been superseded
HEATING AND VENTILATING CONTRACTORS ASSOCIATION
4 Palace Court London W2 4JG Telephone 020-7229 2488 Fax 020-7727 9268
Orders fo FlY A Publications Old Matlsion House Eamont Bridge Penrith Cumbria CA 10 2BX (Telephone 01768 864771 Fax 01768 86718) Email hvcapoblicationshvwelfarecouk DWn 44 pe ilicatiun for sheet mctal duclwork (Iow- mediulllshy
and high-pressure) 1998) DWIl4 A practical guide to dUGI ork I akage te ting
(revised 2000) DWII54 Specification for plastic~ duct rk DW171 Guide to good Practice for kitchen venlibtion system DW191 Guide to good pracuce glass fibre ductwoJk DwrrMI Acceptance cheme for new products - Redangolar cro
joint classification Guide to good pra tice - Internal cleanliness of new ductwork installations Guide to good practice for the design for the Installation of lire and smoke uampers
J 1Other puhlications
HampV safely guide 5th edition JS2 Tool box talks JS5 Weldlng Safety booklet JSI9 afety facts bo klet Fact sheets 1-24 2nd edition JS2J COSHH manual volume 1 Advice on compliance with the
regulations 1521A CO I-rH manual volume 2 Asses mcnt h ets JS23 Ri k management manual TR3 BrazinltT and bronze welding of copper pipework cUld sheet
(I 976) TR5 Welding of carbon steel pipework (1980)
TR6 Guide to Good Practice for Site Pre sure Testing of Pipework (19 0) Guide to good practice cleanliness of ventilation Ylem
CHARTERED IN TITUTlO OF BUILDING SERVICES E G EERS Delta House 222 Balham High Road London SW12 9BS rTelephone 020-8675 5211 Fax 020-8675 5449) CIBSE Guide Volume A Design Data Volume B In tallatiol1 and quipment Data Volume C Reference Data
CommlssioniJIg Codes These Codes eover the preliminary checkS eUing to work and regulation of vanous catcgories 0 plan The Codes give a guide to design implications Series A Air Distnbution Systems Series B Boiler Plant
ri s C Automatic Conlrol ystems Cr1es R Refrigerating Sy terns
Sene iN Water Distribution Systems
Technkal Memonllda TM 4 Design Notes for the Middle East TM bull Design otes for Ductwork TM 13 Minimi iog lhc Risk of egiounaires Disease
Research Reports RROI95 Ventilation system hygiene - A review of published
infomlatioo on lhe occurrence and ffects of Olltamination Rl~02J95 Air-to-air heal rec v ry RR0395 rnfluen e of HV C on smoke detectors
ATlONAL ENI [ERING SPECIFICATION LfMITED Southgatc hamber 3739 Southgate Street Winchester S023 9EH (Telephone 01962 842058 Fax 01962 R(8982) BUfLDING S RVICES RESEARCH AND [ ORMATION ASSOCIATIO Old Bracknell Lane West Bracknell Berkshire RG 12 4AH (Telephone Brackl1eU (01344) 426511 Fax 01344 487 -7 )
Application Guides AGln4 De tglJing Vana~le Volume middotylans for KOOnl
iir Movement AG1I91 Commissioning of V Sylcms in Buildings 11 6194 Fire Dampers
B) 94 cntiJalion or KitcneTls
AG389 The Commls ionin of Air Systems In Buildmgs AH2192 Commissioning of Bern - A ~ode of Practice TN2417 I Fire Dampec il) Ventilating Ducl
BEATING VENTILATING A AIR CONDITION G MA UFACTURERS ASSOCIATIO (HEVAC) HEVAC Henley Road Medmenham Marlow Buck SU 2ER (Telephone 01491 578674 ox 01491 575024 Emoimiddot infofetacouk)
Publicatjons Air Diffusion Guide Guide to Air Handling Unit Leakage Testing Guide to Good Practice Air Handling Unit Real Room Acoustic ~ st Procedure Specification for the ertiiicatioll ofAir Filters Method of Test for Water Rejection PerfOnTlatce of Louvrcs Subjected 1(1
Simulated Rainfall Test Procedure for Acoustic Loo cs Specification 10 Floor GrilJes - Types Performan e and Method ofTest Specification for the Determination of the Collection Efficiency of SilJ1d
Trap Louvre Domestic Mechwlical Vclltllalion Systems with Heal Recovery Fan Application Guid
~an and Ouctwork Installation Guide Guide to Fan Noise and Vibration
pecification of Requirements for JallJral Smoke and Heal Exhausl Ventilators
pecification for Powered Smoke and Heat Exhaust Ventilators
Specification of Requirements for Smoke Curtains Design Gujue of Smoke Ventilation for Single Storey Lodustrilll Building~
Including those with Mezzanine Floor and IIi Racked Storage Warehou es - Issue 3
Guidance for the Design of Smoke entilation YSlem for Covered and Undergrollnd Car Parks - lssue 1
Application of SOloke Control Equipment and Syst m Guid to Good Practice - Isue J
58
DW154 Sp(C~tiifitiol for Plastics Ductwork
BRITISH STANDARDS INSTIT TION Sales Department 101 P ntooviLle Road London NI 9ND (felephone 020-78 1 78801)
CP 413 1973 Ducts for building ervices
SS 476 Fire tes on building matenals and lruc(ure
Part 4 19 4 Non-combustibility lest or materials
Part 6 I Fire propagation lest for materials
Part 7 1993 Surface spread of tlarnJ tesls for materia
Part 20 1987 Fir resistance of elements of construction
Part 21 1987 Fire r sistlUlce of loadbeanng elements of construction
Part 22 1987 Fhe istallceofllon-loadbearing elemcllts ofconsttuclion Part 23 1987 Contribution of componcnts to the fire resistance 0 a
structure
Part 24t987 Fire resi lance of wl1lilation ductl
SS 5588 nan 919 0 Fire Precautions III thc desIgn and OOSlnJ lion of buildings
S 729 1971 Hot dip galvanized oatiugs (or irOIl aod stcel articles
BS 1449 Steel plate sheet and Irip
Pan 11991 Carbon steel plate heel and strip Part 2 1983 Stainless steel plate sheer and strip
and
B middotENJOI49-2 996 BSEN 10149- 1991)
BSEN 10131 1992
BSEN22063 Sprayed metal coarings 1994 Protection of iron and steel by aluminium and zinc against
atmospheric cOlosion Irotectiotl of iron and ste I against corro ion and oxishydation at elevared temperatures
BS 353 1981 Glossary of lerms relnting to thermal insulation
BS ISO 1479 Self-tapplngscrewsandmetallicdri c crew
B -lSO 7049
1994
B 4800 1989 Painl colour for building purposes B 4848 l0 rolled structural steel sections
Part4 1972 Equal and unequal angles BS 5422 1990 Specification for the use of therm illuating matcriulS
SS 5720 1979 ode of practice for mechanical veutilating and air C 11shy
dirionin bull in building
l3S PR 12814-1 Bend resting for plasric welds
SS PR 12814-2 Tensile testing for plastic welds
SS PR 13067 Appro altesting for plastic welds
BS PR EN I 100-] Vi ual in pection ofplaslic welds
SHEET METAL AND AIR CONDITIONING CONTR-CTORS NATIONAL ASSOCIATION INC (SMACNA) Headquarters 420 I Lafayeue Center Drive Chanlilly Virginia 2051-1209
Mailing Address pa Box 221230 Cbantilly Virginilt120 153-1230
Telephone (703) 803-2980 Fax (703) 803-3732
Accepted IJJdustry Pl3Gtice for Industrial Duct Constnlelion 197 ) i-rchitecmral Sheet kwl Manual ([993)
Comractors Guide lor Modification 10 ooslruerion Colllraets 1993 Ducted Eleclric Heat Guide for ir Handling Ssrerns (1994)
En~rgy ollservatioD Guidelines (1984) Energy Recovery Equipment yslClllS (199l
Fibrou GIns Duct onS1ntClion Standards (1992)
Fire Smoke amp Radiation Damper In tall Guide for HVA Syst ms (1992) Guide t leel Stack 1(95)
HVA Air Duct Leakage Test Manual (19 ) HVA COlllmissioning lvlanual (1994)
H A Duct Construction Standards-Metal amp Flexible (1995) Addendum 01 (Nov 1997)
HVA Duct Systems Inspection Guide (1989)
HVA ySlems-Application (1986) nVAC ByternS-DLlct D ign (1990)
HVi Systems-Testing Adjusting amp Balancing (1993)
indoor Air Quality Manual (1993) tcheu quipment Fabrication Guidelmes (1990)
Managers Guide for elding (1993)
Rectangular Industrial Duct Cons1TUction Standards (19 0) Round Industrial Duct oustmction Standards (1977)
Sei mic Restraint Manual (1991) (wl Appendix E 1993) SMACNA Ma le Index ()fTechnical Publications (1995) Tbennoplnstic Duct CPY ) Construction Manual 1994)
DEPARTME OF THE ENVIRO MENT (Publications Centre) H Stationery Oflice 5 Nine Elms Lane London SWS 5DR
MampEJ 011972 Electrical in tallat1011 in buildings ( ew Editiou)
IampE 0319 Healing hot and cold wat r steam and gas losla1lations for buildings
M amp - No4 1970 Central heating and hot and cold ~ ateT in tallations for
dwelling
M amp ENo100 1971 Mechanical ventilation for building~
ASSOCIATION FOR SPECIALIST FIRE PROTECTlO As ociation House 235 Ash Road AJdershot Hampshire GUl2 4DD
Telephone OJ25221322 Fax 0 J252 333901
lublicalioos Fire Ratcd and moke Outlet Ducrwork An Industry Guide t Design and InSlalla lioll
HEALTH AND SAFETY EXEC TIVE Rose Court 2 Southwark Bridge London SEl 9HS Telephone 020-7717 6000
TWJ THE WELD G TlTUTE Abington Hall Abington Cambridge CB16AL Telepbone 0 J223 89162
Publication DatJ Oil w~ldll1g of lhermopla lics
59
DW154 wciiwlioll for Plastics Ductwork
A -=--DIX
Factors
Specific gravity shy pp = 091 approx UPVC = 14 approx
Some miscellaneous conversion factors
To convert
Length Inches to millimetres Feet to metres
Multiply by
2540 03048
To convert
Millimetres to inches Metres to feet
vIultiply by
003937 3281
Area Square inches to square millimetres 6452 Square millimetres to square inches 000155 Square feet to square metres 00929 Square metres to square feet 10764
Volume Cubic feet to cubic metres Cubic feet to litres Gallons (UK) to litres
002832 2831 4546
Cubic metres to cubic feet Litres to cubic feet Litres to gallons (UK)
35315 00353
022
Mass Ounces to grams Pounds to kiJograms Tons to tonnes
2835 04536
1016
Grams to ounces Kilograms to pounds Tonnes to tons
003527 2205
09842
Volume flow Cubic feet per minute to cubic Cubic metres per second to cubic
metres per second 0000472 feet per minute 2119 Cubic feet per mIDute to litres Litres per second to cubic feet
per second 04719 per minute 2119
Motion Feet per minute to metres per second 000508 Metres per second to feet per minute 197
Pressure Inches water gauge to millibars 2491 Inches wateJ- gauge to pascals (Pa) 2491 I Pa = I ewton per square metre = 10-2 millibars
60
Heating and Ventilating Contractors Association Esca House 34 Palace Court London W2 4JG
Tel 020 7313 4900
e-mail contact Itvcaorguk web site wwwhvcaorguk
Fax 020 7727 9268
DW154 Specijimrol1 for Plastics Ductwork
ART 1 4
bullbullbullbullbullbullbullbullbull 41
Technical information to be provided by the desmiddotg er to the plastics ductwork cont actor 42
1 INTRODUCTION 11 Thi specificalion relates to the manufa ture
and installation of rectangular and circular 43 ductwork constructed from plastics The selection of construction method is at the discretion of the manufacturer to conform with the performance requirements of the pecified 44 ductwork clas ification Sections 2-4 blow define the information to be provided by the designer
45 2 STANDARDS
21 Pressure classification (Table 1)
22 Leakage classification (Table 1) 46
23 Positive and Negative pressures (Table I)
24 Materials (Parr 2 Section 7)
25 Any special ystem requirements 47
3 COMPONENTS
31 Access and drainage points Number and location of access doors and drainage points
32 Regulating dampers Specification location and mode of opelatioll of all regulating dampers 48
33 Fire stops Stops to meet the requiremen ts of the Authority directly responsible for fire protection 49
34 Flexible joint connections Sp cification and location of any flexible conne tions eg plant or building expansion joint
PARTICULAR REQU REMENTS
Plastics material Type of plastic material from which the ductwork i to be manufactured and detail of ductwork to special requirements not within this specification
Environmental Env ironmental conditi ons inside and sULToundillg tJle ductwork
Airflow Design airflow volume for all mam ducts branches and air tenninals
Pressurevelocities Design air velocities and pressures for all main ducts principal branches and tenninals
External thermalacoustic insolation he extent and type of insulation to be
provided by others should be stated including full specification for application and installation
Spark testing U spark testing is required the designer shall identify land mark in the contract programme for testing to be undertaken ie manufactur installation corrunissionjng
Air leakage testing The extent of any air leakage testing if required While it shall be mandatory for highshypres ure ductwork (a defined in this specification) to be tested for air leakage iu accordance with the procedure set out in DWI43 A Practical Guide to Ductwork Leakage Testin2 no such te tin of Jaw-oro
mediam-pres Llr duct work is requjJmiddoted
Identification Details of colour coding or identification if required For furth r information see HVCA publication DWl44 Appendix B
Solvent~fomes
Details of design criteria used or adopted to avoid the trapping and discharge of liquid solvent fumes or gases
6
~--
DW154 Specificatio1l for Plastics Ductwork
410 Protective finishes (Part 6 Section J9) Detai Is and specification of any protective finishes
411 Fire retardant finishes (Part 6 Section 23) The extent and limits of protection for any fire retardant finishes on plastic ductwork (Specific references must be defined)
412 Controlssensing equipment Details of positions and fixing configuration of all sensors and test points to suit specialist contml and sensing equipment
413 Special supports (Part 5 Section 14) Details of any spanning primary secondary steelwork or special support requirements not specifically covered by Section 14
414 Attachment to building structure (Part 6 Section 20) Specific requirements for the junction of ductwork and associated components to opening hou1d be detailed and specified with the limits of responsibility defined
Tbe design and provision of penetrations and associated framings are outside the scope of this specification
415 Ductwork layout drawing Details of any special requirement$ relating to CAD scales etc It is common practice and cost effective for duclwork manufacturers to utilise their approved ductwork layout drawings as a basis of their manufacturing installation information by adding the necessary details to the same drawin2 Scales of 150 or smaller may preclude tJlis practice therefore larger scales might be more appropriate The final choice of manufacturing installation scales shall be left to the ductwork contractor
416 Other requirements Details of any requirements far the ductwork not in accordance with the provisions of tbis specification including any modified construction required to conform with any requirements cancerning external ductwork (See 53) or to meet the regulations of a local autbority or athcr controlling body
4 7
Clause
Reference to designer In consideration of the foregoing reference is also made to the designer in the following c1ausesshy
Page 52 8 53 8 106 12 1072 12 111 12 131 16 1352 17 136 17 141 19 144 19 145 19 147 20 152 22 161 22 1631 23 1634 23 171 24 173 24 174 24 181 24 182 27 191 27 211 27 222 28 223 2R 231 28 252 31 Appendix A 49 Appendix B 54 Appendix C 55 Appendix D 56
7
DW154 Spaijicllliflll for Plastics Ductwork
PAR 2 54
Standards
5 APPLICATION
51 This specification sets out minimum requirem nts for tbe manufaclure and in-tallation of ductwork for commercial and industrial fume extraction and exhaust 5y terns made from any of th material listed in Seclion 7 and being within the limit of ize andor material Ihickness speci led in Ihe relevant tables Normal ambient operating temperatures are assumed within the pressurevelocil limits and the limits of air leakage for the various pressur classes prescribed in Table 1
52 Thi specill alion is inlended to apply to ductwork handling fume-laden air which are polluted or is otherwise exceptional in respect of temperarure or humidity (including aturated air) for dllctwork wber the external
surface are exposed to a hostile environment The design construction installati n supports and finishes in such case should be giv n special consideration b the de igner in relation to tbe parti [lIar requir ments of each application
6
61
53 TIlis specification is sllitabl for ductwork expo ed to external atffio phere The designer will need to ~ive sp cift details of any special finish constlUction (See eetiar J9)
62
This specification i ba ed on duct operating environments of not less than - 100e and for
PVC (non GRP reinforced) nor exceeding 40degC UPVC reinforced wilh GRP not exceedin cr
600 e PPS and PP not exceeding 60deg FBPP reinforced witb GRP not exceeding 70degC Systems required to operate at temperatur outside those d tailed above aJthough outside of Ih scop of Ll)is specification are Dot precluded but the ductwork hould be designed from fi rst principle Ilaving regard for the physical mechanical and chemical properties of the material It mu~t be noted that the cOlTosive re i tance of all the above m terials will decrea e at temperatures approaching 5deg to looe below the parent materiaL beat distonion point Further guidance on temperatup effect is provided in Fig 34 Linear Tbennal
xpansion and Fig 35 Typical 0 ign Stres es for VC and PP
DUCTWORK CLASSIFICATION AND A R LEAKAGE
Classification and air leakage limits Duc work la sification and air leakage limitmiddot are eL out in Table 1
Compatibility with CEN The leakage fa tor u ed in able 1 for Classes A Band C ~u-e the ame as those for the cIa e similarly de ignated in th E Document Pr E 12237Pr L507
Table bullbull uctwork Class icati nand ir Leakage Limits (Reproduced from DWI144j
Ducl pressure class
1
Low-pressure -Medium-pressure -High-pressure
-I
I Class A Class B
Class C
Static pr sure limil Air I akage LimitMaximum air
litres per ltccnno per quarevelocity
Positive Negalive metre of duct surface areu
2 4 5 ~ -Pa Pa
f-m1s
0027 X pors500 10500 --1000 0009 x po6~750 20
0003 x pO652000 750 40
Where p is he differential pressure in pascals
Nole Tllls specification DWl54 onJy covers construction up to 1500 Pa
8
- - shy -~----
- shy
DW154 SpeciiCfllioll for Plastics Ductwork
63 Leakage at various pressures and other 110 mm to 600 mm dia (Dimensional rela tionships tolerances to DIN 8062) Applying the limits specified In Table 1 Appendix A (Table 13) sets out the permitted 74 PPS (Forms aailable) leakage at each of a serie of pressures up tu a maximum for each class Incloded in that 741 Extmded sheet in thickness 3 mm to Appendix is a graphical presentation of the 12 mm (Dimensional tolerance to pre urelleakage relationship DIN 53479)
DWl143 A Practical Guide to Ductwork 742 V series tube in sizes 1] 0 mrn lO 630 Leakage Testing provides detai Is of the basis mm dia and fittings in size I 10 mm for the leakage limits specified in Table 1 to 400 mm dia (Dimenional
tolerances DIN 53479) 64 Air leakage testing
Air Jeakage testing of low and medium 743 All PPS material used hall be pressure ductwork is not mandatory under compatible and comply with DIN tJlis specification Air kakage testing of high 4102 part B and SS 476 part 7 class pressure ductvork t mandatory under this 4 PPS material should not be used for specification and for details of testing external applications vithout suitable procedure refer LO DW143 A Practical Guide protection (See Part 6 section 19) to Ductwork Leakage Testing
744 It should be noted thal PP is not fully 7 MATERIALS compatible wilh PPS
71 Application 75 FBPP (Forms aailable) This specification applies to ductwork constructed from materials as defined below 7 51 Sheet in thickness 3 mm to 9 mm or equal Minimum material thickness is to be taken a a nominal thickness as Tables 267 7 52 Continuous roll form in thickness 2 10 amp 11 AJJ UPVC materials ued shall be mm to 4 mm low flammability selfextinguishing compatible and UV stable with pigment colour to RAL 7 53 This particular material is specifically 7011 and DIN 4802 B 1 designed to be externally reinforced
with GRP (See Section 24) 72 Types
The materials covered by thi specification are 76 UPVCGRP abbreviated herein as foIlowsshy This is a form of composite lamjnate used (UPVC) Unplasticised polyvinyl chloride where improved mechanical trengtb UV (PPS) Self eXlioguihing polypropylene stabilisatiolJ or fire retardence is required (PP) Polypropylene (GRP) Gla s reinforced plastic 77 UPVCIFOAMJGRP (FOAM) Rigid polyurethane self FBPPFOAMfGRP
extinguiShing foam This is a form of composite laminate used (FBPP) Fabric backed polypropylene sheet where insulation andor support is required for
special applications 73 UPVC (Forms available)
8 DUCTWORK CONSTRUCTION 731 Extruded sheet in thickness 3 mm to AND JOINT SEALING
12 mm (Dimensional tolerances to DIN 7748) 81 Ductwork construction
The election of longitudillal cross joint and 732 V series tube in sizes 110 mm to stiffener types within the criteria laid dOT1 in
1AOO mm dia and fittings in siz~ Part 3 amp 4 shall be used as a minimum standard
9
DW154 Spet((icatioll for Plastics Ductwork
82 Joint sealing and sealants 8226 The joint mu t be held in po ition ror at leamiddott 5
821 General minutes A jig should be The integrity of the ductwork used jf nece-ltsary to ensure depends on the successful applicatioll that no twisting force i of tbe conemiddot t jointing metbod appl ied to th joint during
the period 822 Solvent cementing
Solvent cementing a atisfactory 8227 Once made the joint method of jointing circular UPVC should not be exposed to socket anu spigot or leeve joints a undue force for eight certain solvent based cement horn shy hour Tb full strength of geneously bond the PVC surface the jOjJlt is not achieved in providing uitabl joints Solvent less than twenty-four cementing i not practicable with PP hours because of its hioh resi tanc to solvents The procedure recommended OTE SOLVENT CEMENT JOINTING by the cement manufacnJrer should METHODS ARE TOT RECOMshybe followed but the following points ME DED FOR RECTANGULAR are important DUCT SECTIONS
[N ALL CASES S ALA MATshy8221 Clearance between ocket ERlALS MUST BE APPLIED
and spigot must be STRICTLY IN ACCORDA CE minimal because of the WITH THE MANUFACTUR ~RS
lirnited gap filling propshy 11 STRUCTIO SAD OSHH ertie of the cement ASSESSMENT
8222 Inside edges of sockets and 823 Hot air welding utside edge of spigot VC and pp a be welded by
shouJd be lightly chamshy Llsing the hot ga Ifil1er rod meUlOd fered ltmd thoroughly cleaned described helow
8223 Mating urfaces should be 8231 The welding gas can be cleaned using a proprietary nitrooen or compressed air solvent cleaner to remove and shltlll b fIltered free grease and slightly etch the from suspended water oil surface vapour and particulate
matter 8224 The cement should be
applied a quickly a 8232 The filler rods shall be possible to the socket and made from material to r pigot over the full area of compatible with the matshythe mating surface are eriaJ being welded should be taken to avoid the use of excessive 8233 Butt weld joints shall be cement bevelled to an included
angle of 60deg to 90deg and 8225 The posi liolling of the joint where po sibl welds shall
mUSl be achieved immedshy be fully penetrated from iately after the cement i both ide of the work applied aJld surplus cement removed
10
DW154 Specificatiol for Plastics Ductwork
8234 The joint face and the filler rod surfaces must be clean and grease fre and preferably roughened b shyfore welding In particular any deposited filler rod that is charred mu t be scraped away before additional runs are added
8235 The numbers of runs of fi lIer rod shall be sufficient to give a thiekne s of era s section of the veld at least equal to the thiekn s of the sheet
8236 Where high frequency park testing i specified lhi shall be undertaken in accordance with tbe weldshying in tmction handbook
Note A full descriplion of welding method is given in the Welding Institut handboo entitled Data on Welding of Thennoplastic Relevant BS amp CE Standards are prEN 12814-1 amp 2 prE 13067 and prE 13100-1
824 Completion of compo ite laminate joints Following solvent ementing or hot air welding of joints campi tion of any specified external laminate shall
carried out to maintain thebe
825
integrity of the construction (S 8227)
Gaskets These can be fabricated from various materials in the form of a pre-formed roll she t or trip applied between opposing faces of fbnced ross joints It i a visable to select material r commended by th ga ket manufacturer for the pecific appucation intended
PART 3
Rectangula ucts
9 RECTANGULAR DUCT SIZES
91 This specification covers duct size up to a rnLltimum longer ide of I -00 mm Duct size with an a peet ralio greater than 4 I ar not recommended Although they offer no problems of construction they increase friclionaJ resi tance and the pos ibility of Dois
10 CONSTRUCTION
101 General Th minimum constructional requiJement r r UPVC and PPPPS un-reinforced are hown in able 2
102 Longitudinal seams Longitudinal seams should Dot be located at corners or in the underside of the duct
103 Sheet jointing seams Seams shall be joined by continuous filler rod hot air welding or by fl1sion Vi ldiug only other form of jointing are not acceptable
104 Socket and spigot joints Sock t and spigot joints shall be formed by purpoe made double cket pi ces 100 mm long and of the ame thiekne material as the duct welded into position on each standard length of duet forming 50 mm de p sockets prepared and ready for final jointing on site with filler [Od of the ame formulation used for prefabrication (See Table 2)
105 Flanged joints
1051 FJa ges Fabricated flanges shall b con tmeted u ing miniumum of 9 mm thick by 50 nun wide material of matching formulation depending on duel size as hown in Table 2 The flange hall be mounted true and square to the duct surface and w lded on both sides a 103 and Figs 3 4 Alternative con truction Illay be
11
DW154 Spedjicfltiotl for Plastics Ductwork
utilised for attacllment to plant or other equipment
1052 Drillings Drjllings shall be placed to permit clearance to tbe extel11al casing and any reinforcement of tbe ductwork for the application of fastening
1053 Fastenings For nonnaJ application bright zinc plated bolts nuts and vashers hall be Llsed in sizes and pitch centres shown in Tabl 3 Where special conditions prevail consideration of other material finishes such as stainless steel bolpounds nuts and washers may be used In all cases gasket materials as Section 825 shaLL be used
106 Expansion joints Wher the configuration of the ductwork does not provide for movement due to temperature change or where such movement is restricted by branches or attachmenL expansion joints should be specified by the designer (See Section 18 FlexibleExpansion joint connections)
It is the re ponsibilir-y of the designer to identify the positions of any necessary expansion joints hased upon design param ters for the individual systems (See Figs 23 to 25 34 amp 35)
Design ote xamples of expansion joints shown in Figs 23 to 25 are not suitable for movement exceeding 30 mm
107 StilJeners
1071 External stiffeners Shall be fitted as specified in Tables 2 amp 10 and Figs 5 amp 6
1072 I temal stiffeners The u e of internal stiffening or bracing shall be acceptable iJ deemed necesary and approved by the designer (See Fig 7)
11 FITTINGS
111 Standardisation of fiuings The terminology and descriptions of rectangular duct fittings a et out in Section 25 are recommended for adoption as standard practice to provide common terms of reference for desi crners quantity surveyor and ductwork contractors and for those using computer in ductwork design and fabrication
Bend are designated as hard or easy and the e terms as used herein have the folJowin o
meanings
Hard signifies rotation in the plane of tb longer side of the cross ection
Easy signiiies rotation in the plane of the shorter side of the cros section
An example iIlu trating these term ] given in Fig 8
Fitting are fabricated by cutting and welding sheet
112 Stiffeners Shall be as 107 and Tables 2 amp 10
113 Splitters Shall be as shown in Fig 41 and welded as 1003
114 ruing vanes Where square bends are required turning vanes as shown in Fig 9 hall be fitted
115 Branches When fitting branch ducts to a main duct care should be taken to ensure that the rigidity- of the duct panel is maintained in terms of tbe sti ffenillg criteria
116 Change shapes Where a change bape is necessary to acconUllOdate the duct and the cross- ectional area is to be maintained the slope haU not exceed 225deg 011 any side (See Figs 52 to 56) Where a change in shape includes a local reduction in duct cras - ectionaJ area the slope should not exceed ISO on any side and tbe reduction in area should not exceed 20 Where tceper angles are necessary due to ile
12
DW154 Spec([icatirJ1l for Plastics Ductwork
restucllOn splitters shall be provided Taper Transformation pieces from circular 10 square pieces reducers and transformation piec s or rectangular shall be made as long a shall be manufactured from the tbickl1 s of p sible and uJe angl ball be uot mor than material specified for the larger size ducl 225 (Fig 55)
loon Pa 1500 Pa
2 3 4 5 6 mm mm mm mm
3 socket amp spigot - - -or tlanged
as Figs 1 2 3 401 to 600 45 flanged 50 x 9 flat 1200 800
50 x 9 flat welded both sides a Fig 3 as Fig 5
601 to 1000 45 flnged 50 x 9 flat 800 600 50 x 9 flat welded both sides as Fig 3 as Fig 5
1001 to 1500 6 anged 75 x 9 flat 600 600 75 x 9 flat welded botb sides as Fig 3 as FieJ 5
or or 70 x 70 x 9 angle 50 x 50 x 5 angle
as Fig 4 welded both sides as Fig 6
N t For constructional operating temp rature limits refer to Part 2 Clause 54
Longer Pitch Bolt Size
Side max 2
mm 1m mm Up to 400 100 8 with washers 401-600 tOO 10 with washers
601middot1000 100 10 with wash rs 1001-1500 100 10 with oycrsized
washer
13
Table 2 inimum con tructional requi ments - rectangUlar nmiddotreinforce UPVC and pp
Joints Sliffeners Maximum spacinOLonger Side MillirnUlll She t between
Thickness Joint~S(iffi ners
mm Up to 400
DW154 SpedflCiltion for Plastics Ductwork
Cross joint - recta gular ducts
Fig 1 Socket and spigot joint (UPVC and PP)
Conlinuou weld joint on sile onlinuou- wcld
CT~r~T2
Fig 3 Flange joint (UPVC and PP)
ontinuou weld
Fig 2 Socket and spigot joint (UPVC only)
Fig 4 Flange joint (UPVC and PP)
S iffeners - rectangular ducts
Fig 5 Flat Fig6 Angle
Oatim wo]
Fig8 Bends - examples of hardTie rod assembly and easy
Hard
Fig7 With spacers Easy
4
DW154 Speci(uariml for Plastics Ductwork
Fig 9 Turning Vanes
HOWl G TYl AL EXAMPLE OF FOCI G
15
Ma vane length shy 615 mm
Example ofbraemg when V1IIle length exeeed max pennined Ahematively two banks of ncs fixmg the centre rail together at ] 50 mm nrrcs
U~_II---- fixed to dnct wall both CDds
bLEVATION
vane
Maximum distance between centrc oflUming vanes should [Jot exceed 60 mm pitch
DW154 SPCCijicllfiull for Plastics Ductwork
practice to provide common terms ofPA T4 reference for designers quantiry urveyor and
Circular Ducts
12 CIRCULAR DUCT SIZES Th duct sizes [n Table 4 have been selected from the ISO and C standard ranges as the 132 preferreod sizes
Table 4 Circular ducts shystandard extruded tube sizes
133 Extruded tube
ISO Standard Sizes (Nominal Diameter) 11
Wan Wall Thickness Thickness
mm mm mm mm 110 500 4022
I25160 600 50 I25200 630 60
225 25 700 60 13425250 800 63
280 900 70 315
23 23 80
355 1000
25 1250 104 400 32 1400 108 450 35
Note The above sizes are subject to normal manufactl1ring tolerances Other size may be available in varying wall Lhicknesses and subject to test and operational pressure
13 CONSTRue ION
13 General Tllis specification covers duct sizes up to a maximum diameter of 1500 mm The minimum constructional requirements for UPVC amp PPPPS un-reinforced ducts sball be as Tables 6 amp 7
ductwork contractors and tho e using computers in ductwork design and fabrication The requirements for circular duct fittings apply throughout the size ranges covered in this specification
Sheet jointing seams Seams shall be joined either by continuous fLiJer rod hot air welding or by fu ion welding Other forms of jointing are not acceptable
Socket and Sl)igot joints Socket and spigot joints shall be formed by purpose made double socket pieces 100 mm long and of the same thickness material as tJJe duct welded into position on each tandard length of duct forming 50 mm deep sockets prepared and ready for final jointing on ite with PVC adhesive andor fill r rod of the same formulation used for fabrication
Flanged joints
1341 Flanges abricated flanges shall be conshy
structed using minimum of 9 mm thick by 50 mm wide material of matching formulation depending on duct size as shown in Tables 6 amp 7 The flange shall be mounted true and square to the duct surfaces and welded OD both sides a 103 and Fig 12
1342 Drilliogs Drilling ball be placed to permit clearance to the external casing and any reinforcement of the ductwork
1343 Fastenings For normal application bright zinc plated bolts nuts and washers hall
16
For srualler diameters preformed fittings are available otberwise fitting are fabricated from segments of duct or sheet welded together
The terminology and description of circular duct tiltings as set Ollt in Section 25 are recommended for adoption as standard
be used in sizes and pitCh centres shown in Table S Wh re special conditions prevail consideration of other material finishes such as stain le steel bolt nuts and wasbers shall be u ed In all ca cs gasket materials as Seciion 825 shall be USed
DW154 Speciliwriml for Plastics Ductwork
135 Stiffeners
1351 External stiffeners Shall be fitted as specified in Tables 67amp 1 I and Fig 13
1352 Internal stiffeners The use of internal stiffening or bracing hall be acceptable if deemed neces ary and appn ved by the designer
f 36 Expansion joints Where the corrfiguration of the ductwork does not provide for movement due to temperature
Cross joints - circular ducts
change or where such movement is restricted by branches or attachments expansion joints should be fitted (See Section 18 Flexible Expansion joint connections)
It is the responsibiLity of the designer to identify the position of any necessary expansion joints based upon design parameters for the individual systems (See Figs 23 24 2534 amp 35)
Design Note Examples of expansion joints shown are not suitable for movement exceeding 30 mm
Fig 10 Socket and spigot joint (UPVC and PP)
ConLinuous weld joim on ite Ontinuous weld
crlr~l
Fig 12 Flange joint (UPVC and PP)
Continllous wcld
boil
Continuous weld or Solvelll cement
Solvelll ccmcnl joim on sile
Fig 11 Socket and spigot joint (UPVC only)
Stiffeners - circular ducts Table 5 Fastening centres shycircular duct flange jointsFig13 Flat
flat conljnlJou~ly welded Diameter Pitch Bolt Size
max
1 2 J 11
1 shy -~
mm mm mm Up to 600 100 8 with washers
601middot1000 100 10 with washers - ---I
1001middot1500 100 10 with oversized washers
1
Minimum offourfixings
17
DW154 Specifiiutiofl for Plastics Ductwork
Table 6 constructional quiremen s - circular unshy inforced U VC
Diameter Minimum Joints Stiffeners Maximum spa ~in r
Sheet between Thickness Jointsl tiffcners
1000 Pa 1500 Pa
1 2 3 4 5 6 UD mm mm mm mm
UO to 600 3 socket amp spigot as Figs 10 11
or fla ged Fig 12
601 to 1000 45 socket amp spigot 50 x 9 flat 2400 2400 as Figs 10 11 welded bo sides
or Oanged as Fig 13 as Fig 12
1001 to 1500 6 Hanged 75 x 9 flat 1200 1200 as Fig 2 welded both ides
as Fig 13
Applies 10 Tables 6 alld 7
Note 1 For constructional operating temperature limit refer to Part 2 luu 54 2 To allow for conicleration or extruded se lions or fabricated component the materia] tllicknes i hawn a nominal
Table 7 Minimu onstrucfional requirements shy circular un-reinforced PPS and
Diameter Minimum Joints Stiffcners Maximum pacio Sheet between
Thickness Join sStiffener 1000 Pa 150n Pa
I 2 3 4 6 mm m m mm
110 to 500 3 socket amp spigot as Fig 10 or flaoged as Fig 12
501 to 750 45 ocket amp spi~ot
as Fi 10 or Uanged as Fig 12
751 to 1000 6 tlanged 50 x 9 Oat UOO 12 0 as Fig 12 welded nth sides
as Fig 13 1 1 to 1250 6 flanged 75 x 9 flat 800shy 800
as Fig 12 welded both sides as Fig 13
1251to~ flangcd 75 x 9 Oat 600 600 as Fig 12 welded both sides
as Fig 13
18
DW154 Sped(icalirm for Plastics Ductwork
PARTS
Hangers an Suppo ts
14 GENERA
141 Supports are an e sentiaJ part of me ductwork system and their supply and in tallation are normally the responsibility of the ductwork contractor The principl s are a I-rvCA publication DWIl44 Part 6 Section 19 and should be read in conjunction with this document
Design Note Designers may pecify specific requirements wbich will supersede guidance given in DW144
142 Rectangular ducts abl 8 give the- minimum requirements for
hanger and supports for un-reinforced ductwork
143 Circular ducts Table 9 gives the minimum requirements for hangers and upports for uD-reinforced ductwork
144 Vertical d cts The design of supports for vertical duct is dictated by site condition and where practical duc hould be upported at 4000 mm interval or where tbey pa s through a floor (but n ver exceeding 4500 mm) see Figs 17 amp J8
145 External ducts Where ducts are external to buildings and may be ubject to wind loading support should be plac d so as to restrain ide tl1ruSt and should allow axial movement as neces ary It is the respon ibility of me de igner to calculate the effect of the particular prevailing condition and to define any special upport requirement
146 Expansion joints Support shall be designed to permit axial movement only and shall e provided on eitl1er ide of expansion joint
I 1shy
I~
mm -Jp to 400
401 to 600 601 to 1000
Table B Hangers and Supports - rectangular horizontal ducts
Hanger Bearer Drop Roll Formed Rod
Long r Side
Cbannel ~-shy ~
---shy
Maximum ~pacing
4 52 3 _ -c Fig 15 - Figs 14 15 16 amp 2J
shy
mmm mmmm 240025 x 25 x 16 40 x 20 x 15 8 240040x20x15 40x 20 x 15 10 240040 x 20 x 1~510 40 x 20 x 15
shy
I
40 x 40 x 15 40 x 40 x 15 24001001 to 1500 I 10
Table 9 Hangers and Supports - circular horizontal ducts
Longer Side Hanoer Split Clips Maximum spacing Drop Roll f-ormed and Wrap-round Rod ~hannel Hang r
2 3 4I Fig 1920 amp 22Fig I
mm mmmm mm mm 25 x 25 x 15 IIp to 355 8 40 x 3- --1-_ 2400
2400
2400 2400
70x 6
40 x 5 SOx 5
40 x 20 x 15 40 x 20 x 15 40 x 40 15
10 10 10
356 to 600 601 to 1000 1001 to 1500
19
DW154 Spccijicutioll for Plastics Ductwork
147 Protection specification Any special coatingpaint Unless otherwise stated all support shall be finishes for protection against hostile manufactured in material as specified in this environments shall be advised by the designer
SUPPORT BEARERS
~ 14 Flg16 Inverted profile
angle I ~lIed steel
channel (alternatives) Fig 15 Profile channel (alternatives)
TYPICmiddotAL VERTICAL DUCT SUPPORTS Flat bar clipStiffening frame Outline ofinsulation stiffening frame or tlanged joint (if applicable) or flanged joint
Stiffening framc or flanged Joint
~~-I ( ee notes 10) I
r--~ -++- ~--4==J===4~---
Fig 17 Vertical rectangular ducts Fig18 Vertical circular ducts
The support bearer which depending on ducti tructural opening size could be either channel or angle section may be ll1ilised in any of the following arrangementsshy
a) To support the underside of a flat bar clip in halves (circular)
b) To support the underidc of either the stiffening frame oftbe flanged joint ofaoy duct section
c) To support either a stiffening frame Or a flanged joint below nsing drop rod srudding
20
DW154 Spediraiml for Plastics Ductwork
Arrangement of bearers and hangers (to be read in conjunction with Table 8 amp 9
wbich list material sizes relative 10 duel izes)
KEY Limits refer to actual duct size - insulation is additional - Typical
attachmentv -Atta hment t strucUlrcI to strucUlrc
I I
I - Flat Bar
I - Drop rod or - utlinc of lllddmg In ulillwn (if
applicable)
Alternative 7 drop rod or rt------------ 1 studdmg q I
I I Rectangular
ii i n 1
Fig 21 Rolled or profiled bearer Limit oncFig 19 Wrap-round hanger Limit 55 DIA
V v Drop rod orAllernaUC 1 1 tudding
drop rod or 1
-- -- 1studding and elded bas 1
I I0 -_
Limit 355 DIA Frg 22 Split clips Limit 1500 DIAFig 20 Flat strap hanger amp split clips
21
DW154 Specification for Plastics Ductwork
6PA deElned in J62 appropriate to the airflow pressure acoustic temperature and corrosion
General
15 ACCESSl SPECTION OPENINGS
151 General These are for inspectionservici ng on 1y
HVCA publication DWIl44 Part 7 - General Section 20 sets out the requirements for access applicable to this specification
152 Cleaningmaintenance Designers shall take specialist advice and then stipulate their requirements for the periodic internal cleaningmaintenance of ductwork and of the consequent need for adequate access for specialist cleaning equipment including the size type and locationfrequency of the actual access openings required
Appendix D sets out guidance notes for the consideration of cleaning access and also makes reference to the HVCA publication TR 17 Guide to Good Practice Cleanliness of Ventilation Systems which covers the su~ject
in greater detail
Note A majority of in tallations in which plastic ductwork is used are considered to have a nigb operational risk potential and provision of access should address this
16 REGULATI G DAMPERS
161 General Balancing dampers and control dampers are elements inserted into an air di tribution system or element of an air distribution sy middottem Balancng dampers permit modification of the air resistance of tbe system and consequently cbanging of the airflow rate Control dampers control tlle airflow rate and may in addition provide low leakage closure of the airflow
The deigner shall specify damper locations taking into consideration that good design practice requires a minimum of five times the diameter or width of the shortest side of uninterrupted flow between plant connections and the damper and select the damper type as
characteristics
1611 Balancing damper To achieve the required distribution of air in the ductwork system at inlets andor outlets for [hi purpose the damper blades are set and Jocked manually in position between fully open and fully closed
1612 Control damper To secure dynamic control of the air now in the ductwork system In thi function the damper will always be power actuated and may require to be modulated between fully open and fully closed and to be capable of taking up any position between these extremes In the fully open position the damper should have a minimum pressure drop In the fully closed position it will not necessarily achieve a complete shut off
162 Types of airflow control dampers Airflow dampers of various types are available for specific purposes as follows
1621 Single - blade dampers Single-blade dampers shall consist of a si ngle pi voted blade cOlllained withjn a casing or section of ductwork The blade shall be adjustable tbmugh a nominal 90 angle by means of a quadrant or similar operating mechanism Where automatic control of the damper is required the spindle shall be extended to enable a powered actllator to be mounted
Single-blade dampers shall have a maximum duct width of 400 nUll and a maximum duct height of 400 mm for rectangular ducts and for circular ducts a maximum diameter of 400 mm
1622 Multi-blade dampers Multi-blade dampers shall consist of a number of pivoted blades contained within a casing The blades shall be
22
DW154 Sedicalirm for Plastics Ductwork
adju table through a nominal 90deg angle simultaneously by intershyconnected linkage or gears connected to a quadrant or similar operating mecbanism Where automatic control of a damper is required a spindle shall be extended to enable a powered achlator to be mounted
There is no restriction on the size of duct in which multi-blade dampers or damper assemblie may be u ed Where dampers are required for blade lengths in excess of 750 mm the blades should be suitably reinforced or supponed 0
individual damper blade should exceed 200 mm in width
1623 Iris dampers Lris dampers shall consist of a nUlllber of radialty interconnected blades which open or close within a casing with duct COlll1cctions The blade shall be simultaneously adjusted by a quadrant or similar operating mechanism
Iris dampers shall be installed as specified by the manufacturers operating and installation instructions where the product is unidirectional with regard to airflow
lris dampers are available for circular ducts only in diameters up to 250 mm (it should be noted that the damper casin i appro)(imately twice the diameter of the duct)
1624 Backdraught dampers Air pressure operated uni-directional rectangular (single or multi-blade) with adapters if fitted to circular ducts
1625 Slide and blast gate dampers A damper [lsed as a shut off facility with an externaJ Lide bousing allowing the blade configuration to be fuJly inserted to fully extended for maxiDlUlll air flow
163 Construction
1631 Materials All products shall be protected against cOHosion as necessary and supplied in a fully finished condition as specified by the designer
1632 Dampers used in low and medium pressure systems The following recommendations apply to dampers forming an integral part of ducrwork with pressure classifications A and B air leakage limits
The dampers shaH be constructed to minimise distortion and prevent jammin in operation Th blade shall be sufficiently rigid to minimise movement when in the locked pOSitiOLl
The blades shall be securely fixed to the operating mechanism All balancing dampers shall have a locking device located on the outsid of the case and shall giv clear indication of the actlwl blad position All penetrations of the duct shall be fitted with suitable seals where necessary
1633 Dampers used in high pressure systems Regulatino- dampers used in duc[work sy tems to pressure cJassification C shall meet tbe construction requireshyments specified in 1631 and 1632 with operating mechanisms out of the air-stream
1634 Proprietary types of damper The use of any specific type of proprietary damper shall be confirmed by the designer In all cases proprietary dampers shall meet the relevant requirements of thi specification
1635 Damper casings Duct damper casings hall be constructed to meet th mllllmum
23
DW154 SpeciJimlioll for Plastics Ductwork
leakage Iim its sp cified for th c1uctwork ystem to which tbey are installed
In order to apply the square metre leakage calculatio as detailed in DW143 A Practical Guide to Ductwork Leakage Testing the reference casing area ball be taken as the perimeter ize of lh damper IDultipli d by the equi alent length of Imetr eg an 800 mm x 400 mm duct damper hall have a surface area for casillg leakag p donnan calculated as follow (2 x 08) + (2 x 04 x I
=24m2 casing area
Other pelforlllance ancl rating test methods for damp f and valves are specified in ISO 5129 and BSIE 1751 and are referenced belm a) Leakage past a closed damper
alve BSIE 1751 b) low ratepre sure requirement
characteri t cs BSIE 1751 c) Operational torque le ring
BSEN 1751 cl) Thermal transfer testing
BSIEN 17 I e) Reg nerated sound power levels
ISO 5129
164 Installation Dampers shall be imaalled in accordance will) any re Ievant ISO EN or British Standard 10 aJ bUT lcling regulation and national code of practice as well as the manufacturers recommendations
17 FIRE DAMPERS AND INT MESCENT SLEEVES
171 General Damper or sleeves arc requiTed on duct y~telll where the designer has -tjpulated the
duct wiU penetrate a fire compartment in the majority of application tbermopla ti ductwork is ugtecl where contamlDated corro ive or otherwise exceptional fumes are concerned it is preferable to use tire damp r which are externalJy mounted ie of the intmnescent operated crush typ
24
72 Fit-e rating The damper assembly should have a fUT
resi tance ratin o equal to that of the fir ban-jer it penetrate and ball be fire tested and rated to the timetemperature curv of B 476 Part 20 and 22
173 Intumescent sleeve At the time of writing this specification qualified test results were available for rectangular dampers and circular dampers up to 55 mm diamet r Manufacture have indicated that they are able t provide speci fications for other size and diameters This infonnation should be confirmed b th de igner Various type are available includino
tho e incorporating ruechanical closing plate and those operated anI by expanded iJllUme c nt media
In all ca es fire damp rs and intnmeBcen leeves shall be supplied and in taUed in
accordance with the manufacturer iJlStructioos and COSHH a essm nt
174 Other types Fire dampers of mious types are availabl for specific purpose~ ee HVCA publication DW144 The de igner should )lot (hat materials for con lt1Jction bould be uitablc for the par1icular application
ALL C SES FIRE DAMPERS AND fNT MESCENT SL _VES SHALL HE S PPLTED AND INSTALLED IN A ORDA CE WITH Tf--IE MANUshyPACTURERS STRUCTTONS AND COSHH ASSESSMENT
18 FLEXIBLEEXPANSION dOINT CONNECTIONS
181 General ploperties Tbe material u ed for flexibleexpan ion iojnt~
mu t meet the design r requirements for temperature air pressllrelfe resistance applicable to pl astic duct sy tem vibration and noi e br akout when incorporated into a jointconnection and shall comply ith lh standard of air-tigbtne specifi cl for the duct work sy tem of which it fOlms part (See Figs 23 24 5 26 27 amp 28 for typical con truclion clelai Is
DW154 SJecilimtol for Plastics Ductwork
Expansion joints
Fig23 Moulded bellows type (rectangular and circular)
Fig24
~F aiblc sleeve
__ liding sleeve
~~~~
Sleeve type (circufar)
Fig 25
AIRFLO
COnlinuou~
weld~
Flexible Iceve
PV A HOWN pp SE BACKING FLATS AS FIG 2
Sliding lee c Co1linuou
weld
Flanged sleeve (rectangular and circular)
25
DW154 Specificatiol for Plastics Ductwork
Flexible con ections
Fig 26 Flexible sleeve with clips (UPVC and PP)
--__ Flexible I eve
I
I
I CODn clioD to plant ~
Band clip
Fig27 Welded flexible sleeve (UPVC only)
Plastic)sed PVC slceve ~-- onll11uo1sly welded
onrreclion to planl ~
Fig28 Flanged flexible connection (UPVC and P )
t sp dally moulded flexible flanged connCClitlll
boil
C)nneclion to plant ~
26
DW154 Specificotiol for Plastics Ductwork
182 LOClt1tion Flexible joint are typicltllly lIsed at building expansion joint and fan inletsoutlets Any others required should be indicated on the de ign drawings Care should be taken to maintain alignment across jointsconnections
183 Length Flexible Jomts shall be kept as short as pra middottieable above a minimum eft ctive length of SO mm In no ca e shall a flexible joint exceed 250 mm in lengtb
184 Connections to rectang a ducts With flanged rectangular connections Ule tlexible material shall be held in pLace with flat pIa tic strip of not less U1an 6 mm thick ltlttached to the flanges using uitabJe fixings The more heavy weight type of fleAible mateLial may also be obtained formed into a channel ection with corners fitted to give a neat air tight j int For pigot connections the Be ible material shall b held in place with flat pIa tic trips n t less than 6 mm thick
t 85 Connections to circular ducts With tlanged circular connections the flexibl material shall be held in place with flat plastic backing strips or proprietary clip bands with screw or toggle fast ners
186 Welded flexible connections (Rectangular and Circular) Where the parent and llexibl material are from imilar ba ed products they can be joined to the duct u ing the welding method described in Section 823
19 PROTECT VE FINISHES
191 nles otherwise stated all ductwork shall be mallllfactured in mat fial as pecified in tbis specification Any special coatingpaint fmishes to be provid d by the duct work contractor sball be advisd by th de igner
20 CONNECTIONS TO BUILDING OPENINGS
201 Fanning and finishing building op nings are not the repoJlsibjlity of the duftw( rk contractor and the note that follow are for guidance purpo e only
2011 Openings in brick block or concrete walls shall have inset frames to provide a suitable means of fixing grille louver masking flanges or the tlanged ends of ductwork The illset frames shall be conslnlcted to maintain the structural int grity of the wlll and where applicable cavities shall be suitably lined
2012 Openin s in dry linino partItIons shall have inset frames a 2011
2013 Openjngs in cladding walls and roofs shall have flaoged leevesframes to provide a suitable means of fixing a 2011
2014 Horizontal and vertical opening xposed to oLltside atmo phere hall
be provided with a suitable weathering fini h at the external face especially where profiled cladding is used
2015 Timber framed op nings are not permitted In fj re compart ment barriers
202 Ductwork connections to building openings hall have a flange of suitable profile to permit practical fixing to the openillg frame In selecting the profile consideration shall be given to Tabl~s 2 and 10 in this specitication relating to duct ize and rating Gasket strip or sealant shall be ltlpplied between the tJaoge and building op ning frame
21 DISCHARGEEXHAUST TERMINAL
21 Tbese shall be vertical open ended and designed to meet and comply with current r gularions on contaminated flue The designer hall ensure that the de ign and perf rmance i suitable for its intended purpose Examples of some typical terminal designs are SbOiD in Figbull 102 10 bull 104 amp 105
27
DW154 SpedjimioTl for Plastics Ductwork
22 THERMAL INSULATION
221 The provision and application of thermal insulation to ductwork is not the responsibility of the ductwork contractor
222 Where ductwork is required to be preshyinsulated the specification should be agreed with tbe designer
223 Where the temperature of the air within the duct promotes condensation on the exterior surface of the duct and cause moisture penetration througb the thermal insulation vapour scaling may be required and in this case the most important requirement is to limit penetration of the seal
The extent of any vapour sealing of ductwork thermal insulation and the support method to be u ed must be clearly pecitled in advance by the designer
224 For detailed information on the thermal insulation of ductwork reference should be made to BS 5422 1990 which covers the specification for thermal insulation materials on pipes ductwork and equipment (in the temperature range -40degC to +700degC) and BS 5970 1992 which is a Code of Practic for Thermal Insulation of Pipework and Equipment (in the temperature range -lOOdegC to +870degC)
23 FIRE RETARDANT FINISHES ON PLAST C DUCTWORK
231 The designer should note tbat ductwork constructed to DW154 has no teted fire rating or information see Appendix C
24 REINFORCEMENT OF DUCTS WITH GRP LAMINATE
241 General Where ductwork is required in larg T izes than are covered by Tables 2 4 6 amp 7 or with the increased strength sometimes necessary for industrial use external reinforcement is normally pwvided by applicatioD of glass fibreresin laminate
GRP systems will bond satisfactorily with standard UPVC sheet but for pp it is
nece sary to use a specially prepared sheet with a glass fabric backing incorporated dOling manufactllfe
The detailed techniques of fabrication using GRP are outside the scope of this speci lcation but the following notes are offered for guidance of ductwork fabricators
242 Materials
2421 Quality The laminate is made up of polyester resin complying with BS 3532 and glass fibre complying with BS 3496 or BS 3749 The nominal ratio of resin to glass fibre should be 7030 by weight
2422 Minimum properties The laminate shall comply with the followiog mini mum pbysical properties
Tensile strength - 70 MNm Tensile modulus - 7 Gl m Flexural strength - 140 M Im Bond strength (hetween laminate and substrate Not less than 7MNm Bmcol hardnes Not le s than manufacturers specification
The GRP reinforcement educe the expansion of the parent material but the resultant stre ses arc well within rhe strength of the bond However the Iinear thermal expansion curve shown in Figs 34 amp 35 will serve as a guide
Surface resistivity electrkal propcltles and acoustical propertie are similar to the relevanl unreinforced materials The fire retarding properties of GRP may be improved by the use of specialisl laminating resin
2423 Forms available GRP Laminate should be built up from the separate materials ie resin aod glass fibre in the form of chopped
I strand mat or spray ravings
28
DW154 Spcification for Plastics Ductwork
2424 Workshop conditions Polyester resuls are sensItIve to lmperature and the workshop hould b maintained at a temperature of herween 20deg and 25degC HiOh relative humidities and damp onditions should be avoided A good rate of air change must be pro icled pJeferably by m chanical ventilation
2425 Storage of materials Resin and urin o agents shouJd be stored in dark cool condirions away from the working area and in confonnit with statutor requireshyments for tJle middottorage of flarmnable liquid Because of Ule Limited torage lif of the unmixed resin and curing a eot mal lials ~hould be ch eked before use to enLlfe that they are within the manufacturer pe ified sh If life (usually ix month from the dm of manufacrure)
Glass fi re should be stored separately und r clean dry conditions
243 Surface preparafon
2431 UPVC To achieve the specified bond strengtll the urface to which the GRP is applied mut first be thoroughly cleaned and then etched either by mechanical means or by the use of a suitable solvent
2432 pp with glass fabric backing To achieve the specified bond middottrength the fabric backing must be thoroughly impregnated Witll resin
244 Mixing the materials for use The re in 1 a three part mix compri lng base I sin hardener and accelerator The manufactur rs pecj[ied proportions are critical and th llUxmg sequenc pecified must be meticulously foUowed
The resin has a very limited life after mixing and before u e It is dependent on the characteri tics and bulk of th resin the alllount of hardener the degree and method of acceleration and the workshop onditions
245 Methods of application
2451 General The mixed resin may be applied by hand or b pray c1epoition The operation must b completed within the gel time of th y tern and tbe laminat fully cOI1olidated to achi v the phy ieal properties pecified
2452 Hand lay-up The duct surface i coated by hand with resin Llsing a brush and a mar of gla fibp orked in until full consolidation achieved Th proc is repeated untiJ th requird thicknes i obtained
2453 Spray depo Won The duct surface is coated WiUl re in by spray gun with the chopped glass roving added through a separate nozzle The full thickne i obtain d in layer with con olidation of each layer by hand roller
246 Construction
2461 General M ini mum COllst ructional requireshyments are pe itied ill Tabl 10 for rectangular and Table 1J for circular dUClS
2462 Joints and stiffeners Fig 29 30 31 32 amp 33 hoI TOSS
joint and tiffener for reinforced UPVC and PBPP duct
247 Worki g practices The fabrication of ductwork pecifiecl ill thi document i not affected by the addition of GRP
29
DW154 SfJcdJicatiOt for Plastics Ductwork
Table 10 Minimum constructional requirements shy
Longer Side Minimum Sheet Thicknes and
GRP Reinforcement
UPVC FBIPP 1 2 3
mm mm mm Up to 1000 3 plus 3 plus
06 kgm2 06 kgOIl GRP GRP
1001 to 2250 45 plus 3 plus 06 kgm 12 kgm
GRP GRP
2251 to 3000 45 plus 6 plus 12 kgm 12 kgm
GRP GRP
Cross Joints
UPVCFBPP 4
mm socket amp spigot
as Fig 30 or flanged as Fig 29
75 x 9 flange welded on both sides as Fig 29
75 x 9 tlange welded on both sides as Fig 29
rectangular GRP reinforced ducts
SlifTeners Maximum Spacing Between
JointsSljffeners UPVCIFBIPP UPVCFBPP
5 6 mm mm
75 x 9 flat 800 as Fig 31 or
50 x 50 x 5 plastic or MS inverted angle as Fig 32
or tormer as Fig 33
75 x 9 flat 600 as Fig 31 or
50 x 50 x 5 plastic or MS inverted angle as Fig 32
or former as Fig 33
75 x 9 flat 600+shyas Fig 31 or 50 x 50 x 5 plastic
or MS inverted angle as Fig 32
or former as Fig 33
Note 1 On rectangular duct up to 400 mm longer side no stiffeners are required 2 Applies to Tables 10 amp I I For COlJstructional operating temperature limits refer to Part 2 clause 5A 3 Tables 10 amp II apply to all pres ure classes up lo ]500 Pa
Table 11
Diameter
1 III
lJp to 1000
1001 to 1750
1751 to 2500
Minimum Sheet Thickness and
GRP Reinforcement
UPVC FBPP 2 3
mm mm 3 plus 3 plus
06 kgm 06 kgm GRP GRP
45 plus 3 plus 06 kgm2 18 kgm
GRP GRP
6 plus 6 plus 12 kglm2 18 kgm1
GRP GRP
Cross Joints
UPVCFBPP 4 III
socket amp spigot as Fig 30 or flaoged as Fig 29
75 x 9 flange welded on both sides as Fig 29
75 x 9 flange welded 00
both sides as Fi 29
inforced ducts
Maximum Spacing Between
JointsStiffeners UPVCIFBPP
6 mm 2400
800
600
Stiffencrs
UPVCFBPP 5
mm 50 x 9 flat as Fig 31
75 x 9 flat as Fig 31 or former as Fig 33 75 x 9 tlat as Fig 31 or t()rmer as Fi 33
ote On extruded tube tip to 600mm diameter no stiffenergt are required
30
DW154 Specificatioll for Plastics Ductwork
G - Cross joints and tiffeners
Fig 29 Flange Joint Fig32 Stiffener shy inverted angle
M artiPfCuQkbdd erttpObri) Wl111 RP tlddtlt
_- GRPloliu] lh~
Fig 30 Socket and spigot joint Fig33 Stiffener shy use of former
Fig 31 Stiffener Flat
I Pv FlPP ~ ~lmJaDUA1) d
OMrlQ rrnall 1( tQlS
25 STANDARD COMPONENT DRAWINGS AND ABBREVIATIONS
251 The illustrations in this section not only highlight where applicable geometric limjtations for the de ign and manufacture or ductwork components but also recommend
standard drawing representation terminology and abbreviations for both duetwork components and some of the more commonly used ancillaryplant items
252 Designers and surveyors should note that bills of quantities should provide a full description
3)
---
v
DW154 Spcc(fim(ml for Plastics Ductwork
Fig 34 Linear Thermal Expansion
u c 0 N ro 0)
b 0)
S
sect0
5 oS cl) 0)
~
on ~ ltl
c U
-30 -20 -10 0 10 20 30 40 50 60 70 80 90 TEMPRATURE C
~ V
-
~~c_ ~
~V
V ~
-7 ~
-- ~V ----
v
-6
+14
+12
+10
+8
+6
+4
+2
0
-2
--4
ig 35 Typical Design Stress tor UPVC and P
7
6
r shy 5E
-c E----0 4t) VJ 0)
ci5 0Jl 3
~
0)
Cl
2
1
o
UPVC
1
000
1
1
pp
- r-- shy r----- shy - t--shy I
__0
-30 -20 -10 0 10 20 30 40 50 60 70 80 90 TEMPERATURE C C
Note Figso 14 amp 35 shaded area refers to GRP reinforced duct
32
DW154 Speciicfltirm for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - REC ~NGULAR
Splilt~r Posilion W-mm pliucr
A B c 40]--QOO 1 W - -
601-1000 1 W4 Wf2 -
1001-1800 3 WI W3 W2
FIG DRAWING DETAfiS
tU]36 ATI Straight Duct with socket and spigol joint
rn [037 Straight Duct with flanged joints
[I []38 Straight Duct with flanged joints
rkJ Short Radius Bend
39 Applies to any augl and for duct up to 400 n11n wide
Minimum (I1m31 radills = 100 mm
Medium Radius Bend (a illustrated)
[kJ Applies to any angle
40 Long Radiu Bend Similar but radius = W
Throlll radius = W2 Applies to any angle
- Short Radius Bend with plitlers
I -shy -shy u co - t lt Li--_ 41 t 0 ~ I I I
~ I
L 1W
Minimum waal radius = 100 mm Splitters not required in bend angle less than 45deg
42 QJ1 Square Bend with turning vanes ij
3
DW154 SP(L~ficatioll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - RECTANGULAR
FIG DRAWl G DETADS
43
~
I v
L L Radius Tee with internal deflectors
44
~ Radiussed Twin Bend
45
Imiddot
er Swept Branch
46 U-
Sqoare Tee with Turning Vanes
47
~ f
Breeches Piece
48 0 y l Piece
34
DW154 Specificatioll for Plastics Ductwork
STANDARD COMPONENT RAWINGS - ECTANGULAR
55
54
51
50
53
52
49
FIG
~MX
RAWlNG
DmiddotMAX
EfjMAX
Minimum throat rndius = 100 mm
Rectangular shy Round Transformatioll
Eccentric Taper 225deg max in either plane Spliller are required for angles greater than 225deg and hould bi eet the angle between any side and duct centreline
DETATLS
Angled Offset
OUset Taper Splitters are required for angle greater than 22 0
and shoold bi eet the angl between any side and dUCI centrelinc
Mitred Offset
Concentrk Taper 2250 max in ither plane SpUtters are required for angle greater than 225deg and should bisect the angle between any side and duel c ntreline
Radiussed Offset
35
DW154 Splcilcuthm for Plastics Ductwork
STANDARD COMPONENT DRAWINGS ~ RECTANGU AR
Branch ducl DimCllsions widlh (W) (A)
urnl mm up lO 200 75
300 100 400 125 600 150
Ocr 600 200
FIG DRAWlNG DETAILS
56 poundplusmni~~ Rectan~lar - Flat Oval Transformation
57 [ Square Branch
58 er Angled Branch
Branch dUCI Dimensions wfdth (W) (A)
[- mm mm59 3shy Shoe Branch Up (0 200 75
--shy AIshy + 300 100
400 125
450 MAX 600 150
Over 600 200
Branch duct DimensIOn
rP X width (W) A)
60 - 1--shy _
~ mm mm
Bell Mouth Branch pto 200 75 300 100 t 400 125
600 150 Over 600 200
0=0 61 -
~ Bell Mouth
- shy T 4-5deg M x
--I 1-shy
TJ
62 X I ] I
Tele-scopic Joint I Illustrated with flangeL
X63
SBD Single Bladed Damper
36
---
DW154 Spedicatioll for Plastics Ductwork
STANDARD OMPONENT DRAWINGS - RECTANGULAR
DRAWING DETAILSFIG
64 on-Return DamperNRD shyshy
shyXbull
Multi-Leaf Damper Can be piggoted or flanged oppo cd or parallel blade
Alternative controls areshy
q p [gtshy
J HD65 Hand
~MD otori ed
PO Pneumalic
L-lt
l 13G 66 Blast Gate DamperX X
FireSmoke DampersSleeves
211r Ratinggtshy----
L_-
---
----
r----
Ir-- shy
IL- _-l
2hr
With i tallation frame
67 41 r Rating
4hr
Smoke damper SD
Intumc cent Sleeve L-d
37
DW154 Specijicutiolt for Plastics Ductwork
FIG
68
69
70
71
STANDARD COMPONET DRAWINGS shy REC ANGULAR
DRAVING DETAILS
gtshy Access Openings
AP 6 Access Panel - Rerno able
w [ ~ Access Door - Hinged
I ~le Inspection Cover
le -I reg -lt
~X X Flexible Connection
~ Drop Cheeked Radiussed Twin Bend
U Drop Cheek Bend
I
72 Air Flow SymbolX
38
DW154 Specifim[ioll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - ECTANGULAR
FIG DRAWING DETAILS
73
74
75
76
77
Q
Q
rp---t
~
V- I Ir---I
JL --11
THE ABOVE DETAILS TYPICAL PLENUM
Air Terminal Plenums
Plenum with side connection
Plenum with top connection
Cover plate with connection
Special plenum with connection
elescopic conn ction in direction of air flow
39
DW154 SpecijicotiOll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG
78
79
80
81
DRAWING
-23~---pound3-(MALE) (FEMAJE)
-t=j--_j(--d-shy
--L
~ THROAT RADI S= D AS T NDARD
e ~
THROAT Rjf)lU = D A MU)
DETAILS
Straight Duct With male and female connectors
Straight Duct With flange joint and slip joint
Bend MouldedIFormed Applies to any angle ego 30deg45deg60deg90deg Medium radius bend as illustrated Long radius similar but throat radius 0
Segmented Bend 90deg four section minjmum as illustrated
Other Angles 60deg = 3 sections 45deg = 3 sections 30deg = 2 sections
I
i
40 shy
DW154 Speciicafinll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG DRAWING DETAlLS
82 Segmented Twin Bend Radius = D2 max
May also be fabricated from tube
83 Equal Tee MouldedIFormed
84 -~ 1in Bend MouldedIFormed
85 Taper Concentric 1 0 as iUu trated Eccentric 30deg iJJcLuded angle
86 Short Taper
41
DW154 SpcUicatol1 for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG DRAWING DETAILS
87 30 max Offset
Angle Branch
Bran h dUCI Dimcnsions dia (D) lA)
Shoe Branch mm mm 88 Cl
Off rectanguJur Up 10 200 75 lOO 10 400 125
- 00 150 Over 600 200
Bl1IllCh duct DimenlOns din (D) (A
~-$a-Conical Branch mm mm
89 Also acceptable with Up 10 200 r
full conical surface 300 10
400 125
END VrE -shy 600 150 Over 600 200
90
m 75
100 12 150 200
mm Up to 200
_ 300 400
600 Over 600
iUtred Branch
Shoe Branch
J-L----U ~ Bell oulh Branch
ENDV1EW
93
92
91
42
DW154 Specificatiol for Plastics Ductwork
STANDARD OMPONENT DRAWINGS - CIRCULAR
FIG
94
DRAW G
I
~ 30deg 090deg
Breeches Piece
DETAILS
95 amp-----~ Blank End
~-----p Multi-Leaf Damper Can be piggolcd or fianged opposed or parallel blade
Alternative controls areshyri=-+- L-T~
I
---
LT~
I r- -
-+1
J HO Hand96
bMD Molori cd
PD Pneumatic
tl-shy bull
Single Bladed Damper 97 ~ saD
on-Return Damper Vertical application only 98 m~D
43
DW154 Sf1tcificatioll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG
99
100
101
102
DRAWING
$ I-
2hr
1 4hr
SD
~v I I
CO TINENTAL COWL
DETAILS
Iris Damper
Fi reS moke Dam persSleeves
2hr Ratillg
With installation frame
4br Rating
Smoke damper
Intumescent Sleeve
Access Openings
Access panel - removable
Access door shy hinged
fnspection cover
Discharge Continental Cowl
44
DW154 Sp(Cii(ltJll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
DRAWINGltIC DETAns
-
I
I
~
I I I High Velocity Discharge Terminal 103 I
I
I I
J I I 1 ~--
Offset Stack Discbarge Terminal 104 1
~ I e --(-
I
N
I
I
I~
I I Vertical Oischarge with Weather Cowl 105 I
--1--1 I
I
GAPI I
RTl AL DISC) lARGE WITH W ATIIER COWL
45
DW154 SpecUicatoll for Plastics Ductwork
STANDARD COMPONE T DRAWINGS - PLA TEQUIPMENTIMISCELLANEOU
FIG DRAWING DETAILS
106 ~~~ Rectangular Attenuator
107 ~- Circular Attenuator
108
~ Beod Attenuator
109 J ~(f) Heating Coil
110 J ftte Cooling Coil
III Jc[ Electric Heating Coil
112 X F
Humidifier
113 [H XX Axial Fan
114 ~fB1famp Noo-standard Ductwork Cross hntchillg (of any separate type) indicates by reference to a key any non DVil54 ductwork system
115 2llIIIIJIIIIIll Flexible Ductwork
46
DW154 SJeCUicll(iol1 for Plastics Ductwork
TABLE 12 - STANDARD ABBREVIAT ONS
ABBREVIATION FLL
AD Acces Door
AFF Axial Flow Fan
AHU Air Handling nit
All Aluminium
AP Acess Panel
AT Attenuator
AV Air enninal Unit
BE 81ank nd
BQ Blast ate Damper
CC Cooling Coil
CF Centrifugal Fan
CTA Cross alk Attenuator
CVU Constant Volume Unit
DP Drain Point
EEC Electric Heating Coil
El Expansion Joint
FAl Fresh Air Inlet
FA From Above
FB From Belo
fBPP Fabric Backed Polypropyl-ne Sheet
Flexle Flexible Connection
lexfD Flexible Du t
C False Ceiling CO an oil Unit
fD Fire Damper
FFL Finished Floor Level
FJ Flanged Joint
FOAM Rigid Polyurethane Self xtinguishing Foam
FOB Flat on Bottom
FOT Flat on Top
GAM Galvanised after ManufacttrJc
GRP Glass Reinforced Plastic
GSS Galvanised Sheet Steel
HC Heating oil
HD and controlled Damper
HH Hand Hole
HL High Level
HVD High Velocity Discharge
IC Inspection Cover
ID lri Damper
IFS Intumescent Fircleevc
47
DW154 Specification for Plastics Ductwork
TABLE 12 - STANDAR ABBREVIATION CONTINUED
ABBREVIATION
IU
L
tv1D
MS
NRD NTS
OBO
OE
PHD
PD
PP
PP
PRD
PVC
RFC
RSC
R
SBO
SO
S1 TST
SSL
TA
TB
TO TJ
TP
TV
TV
OS
UPVC
S
V
VAV
50 RSA
FULL
Induction Unit
Low Level
Motor controlled Damper
Mjld Steel
on Return Damper
at to cale
Opposed Blade Damper
Open End
Parallel Blade Damper
Pneumatic controlled Damper
Polypropylene
Self xtinguishing Polypropylene
Pressure Relief Damper
Polyvinyl Chloride
Rolled Form Chamlel
Rolled Steel Channel
R fUnit
Singl Blade Damper
Smoke Damper
Slip Joint
Stainl t el
tructural Slab Level
To Ab vc
To Blow
Top Down (In Direction of Flow)
Telescopic Joint
Test Point
TU111iog Vane
Top Up (In Direction of Flo )
Voles Otherwise Stated
Unpl3sticisecl Polyvinyl Chloride
Underside
Ultra Violet Light
Variable Air Volume
Rolled Steel Angle (Vith Size)
48
DW154 SJeriiflllioll for Plastics Ductwork
A2 DUCT PRESSUREAPPE DXA Ductwork con truct d to DWIl54 will bebullbullbullbullbullbullbullbullbullbullbullbullbullbull
Air Leakage From Ductwork To be read in conjunction with DW143 A practical guide to Ductwork Leakage Testing
CAUTION As highlighted ill both this docul1lenr and DW14 I lot ellough emphasis can be placed 01 the fact that except for high pressure class C the much more stringent ductwork constructional standard brolght about b the general acceptance of DW154 have irtlally negated the requirement for leakage-testing It is essential lO realise lhat except where it is mandatory this doclllllelll is nOl an endors ~lIlent of the rourine testing of ducts bllt purely a guide to outline the procedures for cononnity with the air leakage limits ill Table l Where the specified methods of assembly and
A3sealing of dlcls are u ed a vi ual inspection wil ordinarily sl~fll e for ver(iatioll of a well engineered and a ceptahfy airtight COl1strucrioll WHERE NOT MANDATORY DUCT LEAKAGE TESTING IS GENERALLY AN UNJUSTIFIED AND SUBSTANTIAL EXPENSE
A1 INTRODUCTION L akage from ducted air distribution systems is an Lmportant consideration in the design and operation of ventilatjon and air conditioning middotystems A ductviork t)ystem tbat ba limited air leakag within defiucd limits wiH cnsUft
that tile design characteristics of the sytem can be maintained It wilJ also ensure that energy and operatLonal cosb are maintained at optimum levels DucLwork constlucted and Ulstalled in accordance with DW154 should minimise a level of air leakage that it) appropriate to tll operating static air pre sur in tile system
A4However it is recouuised that tbe environment in wtJich middotystems are installed is not always conducive to achieving a predictable level of quality in term of system ajr leakage and it is therefore accepted that designer may sometimes require tlle ystem to be tested in part or in total It should be ecogni ed that the testing of duct systems add a ignificant cost to the installation and incur some extra tjm within the programme (Se 47 and 64 re mandatory te-sting)
manufactured to a structural standard that is compatible with the system operating pressure There are three classes of duct con truction to eorre pond with the three pre ure clas meations Class A Lo pressure ducts suita le for a maximum positive operating pressure of 500 Pascal and a maximum negative pressure of -500 Pascals Class B IVledium pressure ductmiddot suitable for a rnaxilnuJJl positive operafjn o pressure of 1000 Pascals and a maxllnum negative pre sure of -750 Pa cal Class C High pre sure ducts suitable for a maximum po ilive operating pressur of 2000 Pa cals and a maximum negativ pres ur of -750 Paltcals
LEAKAGE FROM DUCTWORK Leakao-e front pia tic air ducts occur at the joint~ and is therefore proportional to the total surface area orthe du twork in th system Tb level of leakage i imilarly related to tIle air pres ure in th du t system and whilst there LS n precis formula for calculating the level of air los it i generally accepted that leakage will increase in proportjon to pressure to rbe pOvver of 065 The effect of air leakage from high pressure velocit ductwork is critical tn terms of system perfomlan dege energy consumption and the risk of high frequency noise as ociated with leakage These problems are le critical with medium pressure 10 ity systems but should be con idered Low pres mevelocity ducts present the lowe~t
ri k in tenn of tbe effect of leakage on the operation of the s stern
SYSTEM LEAKAGE LOSS As there i no di ct relatLonship between th volume of air conv yed and the surface area f the ductwork sy tern required to match the building configuratmn it is difficult to express air leakage a a percentage of total air volume Similarly the operating pressure will vary throughollt lh 3 system and a leakage is related to pre me the calculations ar comple However it is generally ac epted tbat in typical good quaJjty systems the leakage from
49
DW154 Specificatioll for Plastics Ductwork
each class of duct llnd r operating condition will be io the region of CIa S A low pressure 6 Clas B medium pres un 3 Clas C high pressure 2
A5 SPECIFYING AIR LEAKAGE TESTING Re peeting both the co -t and programme implications a sociated with te ling du 1 for leakage the designer may for example indicate that a particular system is te ted as follow
a) High pressure ducts - all tested b) Medium pr ssure duets - 10 of the
ductwork shall be s eet d at random and tested
c) Low pre sure - unte ed In any case where a random te t i elected for medium pre sure ductmiddot the followin c1au~e is suggested for inclusion by the de ign r
The designer hall elect at random a maxirnwlI of 10 of the dUCl system to bt tested for air leakage The duct hall be tested af the pressure recommended in Table J3 for the assifi atiol for the ectiol1 of the ductwork that is to be tested The tests shall be carried Ollt as the work proceeds and prior to the application of thermal insulation In the event of test failure of the randomlY selected section the designer shall have The right to select two La1her e tiolls at random for resting Where succes ive failures are identified there shall be a Tight to require rhl COl11raCWr 10 apply remedial attention to the complete ductwork system Th contractor shall provide documented eviden e of the calculalions used to arrive (1
the allowable 10 I for the section to be tested and the client or his agent shall willess and sign the results of the test
able 13 Air leakage rates
Maximum leakage of duct work Static
prcssUft Low-pressure edium-prc-sure I Iigh-prebull me diJfercntial Class A Class B Class C
1 2 J 4 Pa Litres per second per quare metre of surface area 100 054 018 ZOO 084 028 300 110 037 400 132 044 500 153 051 600 058 019 700 064 021 800 069 023 900 075 025
1000 080 027 1100 1200 1300 1400 1500
029 030 032 033 035
1600 1700 1800 1900 2000
036 038 039 040 042
Note Recommend d mean test presures are highlighted iD bold type with the actual selection being left to tll test operator
50
DW154 Sfeeiieaioll for Plastics Ductwork
A9
A10
and air leakage classification for the y em under test
DESIGNERS CALCULATIONS The designer can middotaJculate with reasonable accuracy the predicted total loss from a ystem by
a) Calculating the operatin presure in each ection of the sy tern
b) Calculating the surface area of the ductwork in each correspondin pre lire s ction
c) Calulating the allowabl~ los at the operating pressure for each ection of the system (see table 13 for allowable leakage figures)
VARIABLE PRESSUR S IN SYSTEMS De igner can achieve significant co t saving by matchina operating pressures throughout the system to constmctional standard and appropriate air leakage testing eO the practice of specifying construction tandards for whole duct sy tems based on fan discharge pre sure may incur unnece sary costs on a project For example ome large sy terns ould well be classiC ed for I akage limits as follows
Plant room risers CJas C Main floor distriblltJou CIa B Low pre sure outlets Cla A
A6 SPECIAL CASES There may be ~itLlations on a project where circumstance dictate thal pecial consideration be given to containing air loss s eg a long mn of duclwork may incur a di -proportjonate level of air 10 s In ca es such as thi example the designer can specify an improved tandard of airtighmess ie 80 of alJo~able 10 s for la B Ju ts The designer sbould not specif a CIa C t sI at CIa s C pressure for a CIa s B ducl
A7 SUGG S ED RANGE OF TES ING
A8 TESTING OF PLANT ITEMS Items of inline pJant (eg Fig 106 to 115) will not normaUy be included in an air I akage test The dllctwork contractor may indud such itelllS in tbe te t jf rh quipm ot has a certificate of COnfOlnlity for Ihe pres ure clas
bull High pressure duct bull Medium pre sure ducts bull Low pre sur ducts bull Exposed extract syst ID bull Ceiling void extract
systems bull Secondary ducts from
VAV or fan coil units bull Flexjble duct bull Final connections and
branches to grille and diffusers
100 test See A5 Untested UDt sted
Untested
Untested Untested
Untested
SI
i
DW154 SJecijicafion for Plastics Ductwork
ig 116 Permitted leakage at various pressures
Leakage in litres per second per square metre duct surface area
Vgt
o ltgt 0 ltgt N
ltgt Cgt
0 0 cc
0 0
~
g =
g ~
c 0
J
ltgt 0 I
~ ] tn
ltgt ltgt
In ol
~ 0 ~ 8 ~
~
c ltgt ltgt
~ CJ
~ ~ ~ ~ 8
0shyij
~ ~ ~ t
ltgt ltgt 00
l
~
~ Q
c C
~ rshy
e ltgt
I 1
I Cgt ltgtv
c Co ~
~~ ~ 10
I
0 Cgt
fJshyq 410 ) 1 ltgt
ltgt N
~ shy ltgt ltgt
~ I 1
c
52
DW154 Specificatio for Plastics Ductwork
Example of a completed test sheet Test No
General
Name of job N~ jC43Pt(r2lef Building Repound ~(~~0
Part 1 - Physical details
a Section of duct work to be tested ~(diffPIfff~el1f3rd Floor
b Drawing Number g91~~ c ssure aSSJ L atlOn V~Jl~IRfYgtg~~lPre Cl T Class C
d Test static pressure -(9 raErq~ ~~~~-~~J~~~ ~~ ~~~~ll
Leakaoe factor 9~-tre3$ecMz I OM REFTOTABLE 13)e b bullbullbullbullbullbullbull
f Surface area of duct under test Q~tJJItetre$ CPROMCALCU TIO BELOW)bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull ampampamp bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull
g ]Vlaxi mum permitted leakage -~ (~i~~0 ~~r~~ ~~~l-~-11~ ~~~Q
Part 2 - Test particulars
a Duct static pressure reading 9QFt~q~ ~ middot~~~1 ~~
b Manufacturer and type of liow measuring d vice (-~~~cJ~Y-9Q7EYg c Range of measurement of now measuring device QtP)OQ~(e~~~0I~~~~1~I~ ~~~~~~W~
d Reading of flm measurin o device pmiddot IFROM RIO)ftscag ~
I (DERlVED [ROM CHART SUPPUED WITH RIG US 0 ud)1e Interpreted air flow leakage rate ~(~~~f~~~ (~l~~~~~~~~~~~~~~~~~I
f Duration ~~~~~norn~allY l~ lnil1Ut~~d~~~ it1~ W~ Date of test ~(lITled ut by Wltll s ed by ~ ~
(~lJ MIJLrr) (Si~rrfltJUYJ
Printed Name 1~g0f~ Printed Name ~~Y~9~ and Company 7jl~~~~~( UJd CompanY AB COII$Itallt8
Width and depth or diameter
Periphery ength Area
millimetreS millimetres metre qL1are metre
800 x 750 3100 1755 5440
600 x 650 2500 557 1193
300 x 300 1200 120 144
305 din 958 700 670
250 dia 785 450 353
TOTAL 8000
53
DW154 Specijilarion for Plastics Ductwork
pA XB
Guida ce No es For he ransport Handling and
Storage of uctwork
avoid damage to adjacent duct panels In somc ca es particularly on con acts calling f r repetitive sizes the use of timber jigs and spacers may be justified Where reduced bulk and greater protection are major factor such as consignments for export transporting ductwork in L shape sections may justify the increa ed ite as embly co ts
It is recommended that before a contract is finalised that consideration is given to the subject of site acces material handling and storage as tbcy havgt a strong influence on the cost efficiency of the overall activity of ductwOlk installation
B3 Handling To minilnise th risk of damage duct sections should be clearly identified and deliveries to site should be closely linked to the installation programme so as to avoid accumulation of
B1 Storage and Handling of Ra Material Material should be stored in suitably designed racking out of direct unJight Where possible the e racks should be metal to earth Edges of cut she t may be harp and protective gloves are advised Wearing teel toe-capped boots is recommended Most pIa tic sheet is manufactured with smootb mfaces andor is suppLied with protective coating Care must be taken to prevent accidental lippag of stacked materials Beiuoshy good electrical insulators the movement of stock unless earthed will allow the build up of stati All stock shapes are chemically stable at normal temperature Whil t some raw materials used in their manufacture may themselves pre ent a toxic hazard once incorporated into the lOck bape they no long r constitute such a hazard and no dermatitic bazard are known nor are any
unfiJied ductwork and minimise double handling It is important to recognise that ductwork panels joint and corners arc susceptible to damage and care must be taken wheu band ling such material through a site During handling individual item of duct work may be liable to light cross sectional deformation until thev become an integral pan of a completed ductwork system Whilst this may temporarily detract from its intended appearance thi deformation will not have any detrimental effect on the functionality of the finally a semblecl system Installation of duct work and asociated plant items ill illevitably involve manual handUng The responsibi Iiry of employers and employees to a ses the risk of personal injury during mallual handling operations is et out in the HS E publication L23 Guidance on Manual Handling Regulations 1992
environmental problems expected 84 Site storage
B2 fransport Large capacity vehicles with high-sided open or closed-top bodies are tlle mo t suitable for the transport of dllctwork Careful consideration should be given to the
Adequate floor space IDust be provided within tbe building for the site storage of ductvork Such storage shalt make due allowance for thc stOf(ne of ductwork in stacks such that access ~ egt
between them is of sufficient width to pennil the removal of item without interference to
unloading of transport on sit a not all siJes b n fit from the material handlino- and access facilities that exi [ in a manufacturing workshop such as crane- fork-lifts or loading bay Site handJiog facilities along with
adjoining sta ks Ductvork components should be positioned so a to avoid crushing Ductwork of small panel size may be stored horizontally however care should be exercised to ensure that tack sizes are limited 10 within
ehicular acce s restrictions may itilluence the type and ize of transport to be uWised
engtlls of ductwork should be positioned 0
the tmctural strength of the duct sections to prevent distortion of the lower sections within the stack
as to avoid crushing Lengths Witll projections such as branches and bends i1anges girths damper quadrauL should be loaded so as to
54
DW154 S1tciic(ltioll for Plastics Ductwork
85 Internal cleanliness of new ductwork The site storage of ductwork introduces the important cODsideration of maintaining the internal cleanliness of the ductwork R feren e should be made to HVCA documentshybull DWffM2 Guide to Good Practice - internal
Cleanliness of New Ductwork Installations If the above conditioDs can not be satisfied consideration should be given by tJle designer to amending the specification to include for Po t Installation Cleaning as covered by tJ1C HVCA documentshybull TRJ17 Guide to Good Practic - Cleanliness
of Ventilation Systems
APPE DIXC
Fi e Retardant inishes C1 Improvement in the fire retardancy of plastic
ducts can be achieved to varying degrees and is wholly dependent llPOll the surface coating laminating resin selected and construction specification adopted In some instances smoke emission is coILSidered equaUy with other speci fication requirernen ts of the materials resistance to ignition and bumjng It is therefore important for design rs to establ ish the clients and officers detailed requirements and not rely on a tbird party interpretation of fire resisting or fire retardant Where possible the specification should refer dir etly to compliance with a British or European Standard identifying the specific sections applicable There are various types of resin and mat rcLnforcements that can achieve a Class 1 surface spread of flame ratin o when tested according to BS476 Part 7 (1987) This test puts materials illto Class I - 4 in descending order of perfoDllance according to the rat and extent of flame spread over their surfac under standard beating conditions Materials should also be tested for flre propagarion to BS476 Part 6 (1989) Tbi tesr measures the amount and rate of heat evolved by the material when subjected to standard heating
conditions Test results are given as an index of Perfonnance (i) whicb is based on three sub indices (iJ (i1) (h) The higher the value of the Index of Performance (i) the greater is the material s contribution to fire growth The higher the value of the sub-index 0) rhe greater the ease of ignition aod flame spread The highest product performance classification as defined in Approved Document B of the Building Regulations is Class O This is acLlieved if a material surface of a composite ploduct i~ either a) composed throughout of materials of
limited combustibility or b) a Class I material which has a tlre
propagation index (i) of not more than 12 and sub-index (i l ) of nor more than 6
01 J Class 0 is not a cla$sif1cation identified in any British Standard test
There are resin system reported to be classified to Class O when tested to BS476 Pcl1S 6 and 7 however designers need to ensure that such sysrems can be applied to their proposed design In propriety resinmat system available the fabrication techniques and COITect application are critical to the integrity of the reinforcing and clas ificatiol1 For example in some systems the u e of a non-fire retardant gelcont on a fire retardant substrate would reduce the classification For further information see HVCA publication DW144 Appendix D
55
DW154 SplCijiClIliol1 for Plastics Ductwork
x Guidance otes For nspectmiddoton Servicing a d
Clean-ng Access Openings
D1 GE ERAL This appendix highlight in ummary fOI111
the acce considerations that hould be made by the design r iD terms of inspection servicing and cleaning Having considered the seop and the design of the dUCI work system relative to the guidelines outlined below the designer should clearly indicate which levels of acces should be incorporated into the manufacture of a new duct work system (See Table 14 and Note I b low it
D2 DESIGN CONSIDERATIONS
D21 In ptction and servicing requireshyments are set out in Section 15 of Lhis specification
D22 Cleaning requirements are set out in the HVCA pubUcation TRl7 Guide to Good Practice Clean Lines of Ventilation Systems and the guide tates The precise location ize and
type of access would be dependent on the type of ductwork cleaning inspection and te ting metbods to b adopted Care protection and standards of cleanliness prior LO cOlllmisionin o
are set out in th AV A publication DWITM2 Guide to Good Practice Internal Cleanliness of New Ductwork Installations and th guide state Wh re specific limits of cleanliness are required ductwork sball be cleaned after installation by a spcialist cleaning contractor It will b in the interests of tht desioner botb financially and practically to cunsider employing a specialist c1eauing contractor at tbe
outset of a contract to internally clean newly installed ductwork prior to bandover This approach would reali e the following benefit shyi) Tb actual numb r of cleaning
access panels could be detennined to suit the method of cleaning to be adopted (This may be 1 s than the maximum requiremen listed under Lev 13 of Table 14)
ii) Clear directions could b given to the ductwork contractor as to tJle size and location of cleaning access panels that are required to be fitted during the mauushyfaclunng pro s
iii) The specialist cleaning operation prior to commi ioning vould enable the cleaning contractor to verify the practical acee requirement for the future cleaning operation associated -vitb a regular maintenance programme
iv) A specialist cleaning operation prior to commissioning would allow the designer to omit from the speeilicatiolJ the DWrrM2 requirem nt for factory sealing protection wipe downs and capping-off
v) Specialist Ieall ill 0 to the measurable standard defin d in TR17 will allow an objective definition of cleanline to be achieved
Car ful consideration must be gIven by the designer to the practl aJ problems associated witb the manufacture and fitting of suitably si Led access panel on small cross section duct and on the circular faces of rouod and flat oval ducts in particular
D23 Special con ideration must be given by the de igner to the practical problems associated with gaining personnel access to heavily congested ceiling areas and multi-la red du twork systems This approach would avoid
56
DW154 Spfciication for Plastics Ductwork
the possibility of access panels being D3 ACCESS 0 IN-LINE EQUIPMENT incorporated into a ductwork system at the This appendix unly covers acc il1spection manufacturing stage that were later found in through the ductwork body adjacent to an item practice to be inaccessible for either ervicing of in-line equipment and not openings in the or cleaning activities equipment itself
able 14 Acce requirements for inspection servicing and cleaning
HVCA PUBLICATIO REFE NeE (uidtgt 10 Gund Prartict
Adjace t OW144 Cleanliness orVcnlillltio S~lcr~ fRjJ7
in-line LeyeJ 1 Level 2 Level 3 ite sequipment pcdionSen lcin~ Section d C1eaniJl( SUn(O)lnspc lion Palle ltk~m_n
2011 (minimum OiL Jubje-ct to duct ~zel (ft~ -Panels
Control Da pcrs One (inspection) 203 One 300 mm x 200 mm Both sid Fire Dampers One (sCTjdJl~) 20211 One 300 0101 x 200 mm One side HeatingCooling Coils One (inspedion) 20213 One 300 mm x 200 mm (lIpstream) Both sides Attenuators (rectangular) None required One 300 mm x 200 mm (downstream) Both sides Attenuators (circular) one retluired One 300 mm x 200 mm (downstream) One side Filter Sections One (inspection) 20212 one required Uoth sides Air Turn Vanes None requjred None required Both sides Changes of Direction None required one required One side In-Duct FansDevices One (inspection) 20213 None required Both sides l
1 In the absence of any indication by the designer only Level ) access will be jncorporated into a new ductwork system
2 Tbe panel izes associated with Lev lis I and 3 acee s ar e middottablished by reference to Section 20 of DW144 and Section 2 ofTRll7 respectively
57
DW154 Speclfifatio for Plastics Ductwork
pA XE
B-bliography Included in this Bibliography are technical pUblications which may be of interest (0 ductwork designers fabricators and erectors and to tho e in the heating ventilatlng air conditioning industries generally nquiric should be made of the relevant organisation at the address quoted Since its publication other addresse contained within 0V154 mav have changed and some pubJicalions may have been superseded
HEATING AND VENTILATING CONTRACTORS ASSOCIATION
4 Palace Court London W2 4JG Telephone 020-7229 2488 Fax 020-7727 9268
Orders fo FlY A Publications Old Matlsion House Eamont Bridge Penrith Cumbria CA 10 2BX (Telephone 01768 864771 Fax 01768 86718) Email hvcapoblicationshvwelfarecouk DWn 44 pe ilicatiun for sheet mctal duclwork (Iow- mediulllshy
and high-pressure) 1998) DWIl4 A practical guide to dUGI ork I akage te ting
(revised 2000) DWII54 Specification for plastic~ duct rk DW171 Guide to good Practice for kitchen venlibtion system DW191 Guide to good pracuce glass fibre ductwoJk DwrrMI Acceptance cheme for new products - Redangolar cro
joint classification Guide to good pra tice - Internal cleanliness of new ductwork installations Guide to good practice for the design for the Installation of lire and smoke uampers
J 1Other puhlications
HampV safely guide 5th edition JS2 Tool box talks JS5 Weldlng Safety booklet JSI9 afety facts bo klet Fact sheets 1-24 2nd edition JS2J COSHH manual volume 1 Advice on compliance with the
regulations 1521A CO I-rH manual volume 2 Asses mcnt h ets JS23 Ri k management manual TR3 BrazinltT and bronze welding of copper pipework cUld sheet
(I 976) TR5 Welding of carbon steel pipework (1980)
TR6 Guide to Good Practice for Site Pre sure Testing of Pipework (19 0) Guide to good practice cleanliness of ventilation Ylem
CHARTERED IN TITUTlO OF BUILDING SERVICES E G EERS Delta House 222 Balham High Road London SW12 9BS rTelephone 020-8675 5211 Fax 020-8675 5449) CIBSE Guide Volume A Design Data Volume B In tallatiol1 and quipment Data Volume C Reference Data
CommlssioniJIg Codes These Codes eover the preliminary checkS eUing to work and regulation of vanous catcgories 0 plan The Codes give a guide to design implications Series A Air Distnbution Systems Series B Boiler Plant
ri s C Automatic Conlrol ystems Cr1es R Refrigerating Sy terns
Sene iN Water Distribution Systems
Technkal Memonllda TM 4 Design Notes for the Middle East TM bull Design otes for Ductwork TM 13 Minimi iog lhc Risk of egiounaires Disease
Research Reports RROI95 Ventilation system hygiene - A review of published
infomlatioo on lhe occurrence and ffects of Olltamination Rl~02J95 Air-to-air heal rec v ry RR0395 rnfluen e of HV C on smoke detectors
ATlONAL ENI [ERING SPECIFICATION LfMITED Southgatc hamber 3739 Southgate Street Winchester S023 9EH (Telephone 01962 842058 Fax 01962 R(8982) BUfLDING S RVICES RESEARCH AND [ ORMATION ASSOCIATIO Old Bracknell Lane West Bracknell Berkshire RG 12 4AH (Telephone Brackl1eU (01344) 426511 Fax 01344 487 -7 )
Application Guides AGln4 De tglJing Vana~le Volume middotylans for KOOnl
iir Movement AG1I91 Commissioning of V Sylcms in Buildings 11 6194 Fire Dampers
B) 94 cntiJalion or KitcneTls
AG389 The Commls ionin of Air Systems In Buildmgs AH2192 Commissioning of Bern - A ~ode of Practice TN2417 I Fire Dampec il) Ventilating Ducl
BEATING VENTILATING A AIR CONDITION G MA UFACTURERS ASSOCIATIO (HEVAC) HEVAC Henley Road Medmenham Marlow Buck SU 2ER (Telephone 01491 578674 ox 01491 575024 Emoimiddot infofetacouk)
Publicatjons Air Diffusion Guide Guide to Air Handling Unit Leakage Testing Guide to Good Practice Air Handling Unit Real Room Acoustic ~ st Procedure Specification for the ertiiicatioll ofAir Filters Method of Test for Water Rejection PerfOnTlatce of Louvrcs Subjected 1(1
Simulated Rainfall Test Procedure for Acoustic Loo cs Specification 10 Floor GrilJes - Types Performan e and Method ofTest Specification for the Determination of the Collection Efficiency of SilJ1d
Trap Louvre Domestic Mechwlical Vclltllalion Systems with Heal Recovery Fan Application Guid
~an and Ouctwork Installation Guide Guide to Fan Noise and Vibration
pecification of Requirements for JallJral Smoke and Heal Exhausl Ventilators
pecification for Powered Smoke and Heat Exhaust Ventilators
Specification of Requirements for Smoke Curtains Design Gujue of Smoke Ventilation for Single Storey Lodustrilll Building~
Including those with Mezzanine Floor and IIi Racked Storage Warehou es - Issue 3
Guidance for the Design of Smoke entilation YSlem for Covered and Undergrollnd Car Parks - lssue 1
Application of SOloke Control Equipment and Syst m Guid to Good Practice - Isue J
58
DW154 Sp(C~tiifitiol for Plastics Ductwork
BRITISH STANDARDS INSTIT TION Sales Department 101 P ntooviLle Road London NI 9ND (felephone 020-78 1 78801)
CP 413 1973 Ducts for building ervices
SS 476 Fire tes on building matenals and lruc(ure
Part 4 19 4 Non-combustibility lest or materials
Part 6 I Fire propagation lest for materials
Part 7 1993 Surface spread of tlarnJ tesls for materia
Part 20 1987 Fir resistance of elements of construction
Part 21 1987 Fire r sistlUlce of loadbeanng elements of construction
Part 22 1987 Fhe istallceofllon-loadbearing elemcllts ofconsttuclion Part 23 1987 Contribution of componcnts to the fire resistance 0 a
structure
Part 24t987 Fire resi lance of wl1lilation ductl
SS 5588 nan 919 0 Fire Precautions III thc desIgn and OOSlnJ lion of buildings
S 729 1971 Hot dip galvanized oatiugs (or irOIl aod stcel articles
BS 1449 Steel plate sheet and Irip
Pan 11991 Carbon steel plate heel and strip Part 2 1983 Stainless steel plate sheer and strip
and
B middotENJOI49-2 996 BSEN 10149- 1991)
BSEN 10131 1992
BSEN22063 Sprayed metal coarings 1994 Protection of iron and steel by aluminium and zinc against
atmospheric cOlosion Irotectiotl of iron and ste I against corro ion and oxishydation at elevared temperatures
BS 353 1981 Glossary of lerms relnting to thermal insulation
BS ISO 1479 Self-tapplngscrewsandmetallicdri c crew
B -lSO 7049
1994
B 4800 1989 Painl colour for building purposes B 4848 l0 rolled structural steel sections
Part4 1972 Equal and unequal angles BS 5422 1990 Specification for the use of therm illuating matcriulS
SS 5720 1979 ode of practice for mechanical veutilating and air C 11shy
dirionin bull in building
l3S PR 12814-1 Bend resting for plasric welds
SS PR 12814-2 Tensile testing for plastic welds
SS PR 13067 Appro altesting for plastic welds
BS PR EN I 100-] Vi ual in pection ofplaslic welds
SHEET METAL AND AIR CONDITIONING CONTR-CTORS NATIONAL ASSOCIATION INC (SMACNA) Headquarters 420 I Lafayeue Center Drive Chanlilly Virginia 2051-1209
Mailing Address pa Box 221230 Cbantilly Virginilt120 153-1230
Telephone (703) 803-2980 Fax (703) 803-3732
Accepted IJJdustry Pl3Gtice for Industrial Duct Constnlelion 197 ) i-rchitecmral Sheet kwl Manual ([993)
Comractors Guide lor Modification 10 ooslruerion Colllraets 1993 Ducted Eleclric Heat Guide for ir Handling Ssrerns (1994)
En~rgy ollservatioD Guidelines (1984) Energy Recovery Equipment yslClllS (199l
Fibrou GIns Duct onS1ntClion Standards (1992)
Fire Smoke amp Radiation Damper In tall Guide for HVA Syst ms (1992) Guide t leel Stack 1(95)
HVA Air Duct Leakage Test Manual (19 ) HVA COlllmissioning lvlanual (1994)
H A Duct Construction Standards-Metal amp Flexible (1995) Addendum 01 (Nov 1997)
HVA Duct Systems Inspection Guide (1989)
HVA ySlems-Application (1986) nVAC ByternS-DLlct D ign (1990)
HVi Systems-Testing Adjusting amp Balancing (1993)
indoor Air Quality Manual (1993) tcheu quipment Fabrication Guidelmes (1990)
Managers Guide for elding (1993)
Rectangular Industrial Duct Cons1TUction Standards (19 0) Round Industrial Duct oustmction Standards (1977)
Sei mic Restraint Manual (1991) (wl Appendix E 1993) SMACNA Ma le Index ()fTechnical Publications (1995) Tbennoplnstic Duct CPY ) Construction Manual 1994)
DEPARTME OF THE ENVIRO MENT (Publications Centre) H Stationery Oflice 5 Nine Elms Lane London SWS 5DR
MampEJ 011972 Electrical in tallat1011 in buildings ( ew Editiou)
IampE 0319 Healing hot and cold wat r steam and gas losla1lations for buildings
M amp - No4 1970 Central heating and hot and cold ~ ateT in tallations for
dwelling
M amp ENo100 1971 Mechanical ventilation for building~
ASSOCIATION FOR SPECIALIST FIRE PROTECTlO As ociation House 235 Ash Road AJdershot Hampshire GUl2 4DD
Telephone OJ25221322 Fax 0 J252 333901
lublicalioos Fire Ratcd and moke Outlet Ducrwork An Industry Guide t Design and InSlalla lioll
HEALTH AND SAFETY EXEC TIVE Rose Court 2 Southwark Bridge London SEl 9HS Telephone 020-7717 6000
TWJ THE WELD G TlTUTE Abington Hall Abington Cambridge CB16AL Telepbone 0 J223 89162
Publication DatJ Oil w~ldll1g of lhermopla lics
59
DW154 wciiwlioll for Plastics Ductwork
A -=--DIX
Factors
Specific gravity shy pp = 091 approx UPVC = 14 approx
Some miscellaneous conversion factors
To convert
Length Inches to millimetres Feet to metres
Multiply by
2540 03048
To convert
Millimetres to inches Metres to feet
vIultiply by
003937 3281
Area Square inches to square millimetres 6452 Square millimetres to square inches 000155 Square feet to square metres 00929 Square metres to square feet 10764
Volume Cubic feet to cubic metres Cubic feet to litres Gallons (UK) to litres
002832 2831 4546
Cubic metres to cubic feet Litres to cubic feet Litres to gallons (UK)
35315 00353
022
Mass Ounces to grams Pounds to kiJograms Tons to tonnes
2835 04536
1016
Grams to ounces Kilograms to pounds Tonnes to tons
003527 2205
09842
Volume flow Cubic feet per minute to cubic Cubic metres per second to cubic
metres per second 0000472 feet per minute 2119 Cubic feet per mIDute to litres Litres per second to cubic feet
per second 04719 per minute 2119
Motion Feet per minute to metres per second 000508 Metres per second to feet per minute 197
Pressure Inches water gauge to millibars 2491 Inches wateJ- gauge to pascals (Pa) 2491 I Pa = I ewton per square metre = 10-2 millibars
60
Heating and Ventilating Contractors Association Esca House 34 Palace Court London W2 4JG
Tel 020 7313 4900
e-mail contact Itvcaorguk web site wwwhvcaorguk
Fax 020 7727 9268
DW154 Specificatio1l for Plastics Ductwork
410 Protective finishes (Part 6 Section J9) Detai Is and specification of any protective finishes
411 Fire retardant finishes (Part 6 Section 23) The extent and limits of protection for any fire retardant finishes on plastic ductwork (Specific references must be defined)
412 Controlssensing equipment Details of positions and fixing configuration of all sensors and test points to suit specialist contml and sensing equipment
413 Special supports (Part 5 Section 14) Details of any spanning primary secondary steelwork or special support requirements not specifically covered by Section 14
414 Attachment to building structure (Part 6 Section 20) Specific requirements for the junction of ductwork and associated components to opening hou1d be detailed and specified with the limits of responsibility defined
Tbe design and provision of penetrations and associated framings are outside the scope of this specification
415 Ductwork layout drawing Details of any special requirement$ relating to CAD scales etc It is common practice and cost effective for duclwork manufacturers to utilise their approved ductwork layout drawings as a basis of their manufacturing installation information by adding the necessary details to the same drawin2 Scales of 150 or smaller may preclude tJlis practice therefore larger scales might be more appropriate The final choice of manufacturing installation scales shall be left to the ductwork contractor
416 Other requirements Details of any requirements far the ductwork not in accordance with the provisions of tbis specification including any modified construction required to conform with any requirements cancerning external ductwork (See 53) or to meet the regulations of a local autbority or athcr controlling body
4 7
Clause
Reference to designer In consideration of the foregoing reference is also made to the designer in the following c1ausesshy
Page 52 8 53 8 106 12 1072 12 111 12 131 16 1352 17 136 17 141 19 144 19 145 19 147 20 152 22 161 22 1631 23 1634 23 171 24 173 24 174 24 181 24 182 27 191 27 211 27 222 28 223 2R 231 28 252 31 Appendix A 49 Appendix B 54 Appendix C 55 Appendix D 56
7
DW154 Spaijicllliflll for Plastics Ductwork
PAR 2 54
Standards
5 APPLICATION
51 This specification sets out minimum requirem nts for tbe manufaclure and in-tallation of ductwork for commercial and industrial fume extraction and exhaust 5y terns made from any of th material listed in Seclion 7 and being within the limit of ize andor material Ihickness speci led in Ihe relevant tables Normal ambient operating temperatures are assumed within the pressurevelocil limits and the limits of air leakage for the various pressur classes prescribed in Table 1
52 Thi specill alion is inlended to apply to ductwork handling fume-laden air which are polluted or is otherwise exceptional in respect of temperarure or humidity (including aturated air) for dllctwork wber the external
surface are exposed to a hostile environment The design construction installati n supports and finishes in such case should be giv n special consideration b the de igner in relation to tbe parti [lIar requir ments of each application
6
61
53 TIlis specification is sllitabl for ductwork expo ed to external atffio phere The designer will need to ~ive sp cift details of any special finish constlUction (See eetiar J9)
62
This specification i ba ed on duct operating environments of not less than - 100e and for
PVC (non GRP reinforced) nor exceeding 40degC UPVC reinforced wilh GRP not exceedin cr
600 e PPS and PP not exceeding 60deg FBPP reinforced witb GRP not exceeding 70degC Systems required to operate at temperatur outside those d tailed above aJthough outside of Ih scop of Ll)is specification are Dot precluded but the ductwork hould be designed from fi rst principle Ilaving regard for the physical mechanical and chemical properties of the material It mu~t be noted that the cOlTosive re i tance of all the above m terials will decrea e at temperatures approaching 5deg to looe below the parent materiaL beat distonion point Further guidance on temperatup effect is provided in Fig 34 Linear Tbennal
xpansion and Fig 35 Typical 0 ign Stres es for VC and PP
DUCTWORK CLASSIFICATION AND A R LEAKAGE
Classification and air leakage limits Duc work la sification and air leakage limitmiddot are eL out in Table 1
Compatibility with CEN The leakage fa tor u ed in able 1 for Classes A Band C ~u-e the ame as those for the cIa e similarly de ignated in th E Document Pr E 12237Pr L507
Table bullbull uctwork Class icati nand ir Leakage Limits (Reproduced from DWI144j
Ducl pressure class
1
Low-pressure -Medium-pressure -High-pressure
-I
I Class A Class B
Class C
Static pr sure limil Air I akage LimitMaximum air
litres per ltccnno per quarevelocity
Positive Negalive metre of duct surface areu
2 4 5 ~ -Pa Pa
f-m1s
0027 X pors500 10500 --1000 0009 x po6~750 20
0003 x pO652000 750 40
Where p is he differential pressure in pascals
Nole Tllls specification DWl54 onJy covers construction up to 1500 Pa
8
- - shy -~----
- shy
DW154 SpeciiCfllioll for Plastics Ductwork
63 Leakage at various pressures and other 110 mm to 600 mm dia (Dimensional rela tionships tolerances to DIN 8062) Applying the limits specified In Table 1 Appendix A (Table 13) sets out the permitted 74 PPS (Forms aailable) leakage at each of a serie of pressures up tu a maximum for each class Incloded in that 741 Extmded sheet in thickness 3 mm to Appendix is a graphical presentation of the 12 mm (Dimensional tolerance to pre urelleakage relationship DIN 53479)
DWl143 A Practical Guide to Ductwork 742 V series tube in sizes 1] 0 mrn lO 630 Leakage Testing provides detai Is of the basis mm dia and fittings in size I 10 mm for the leakage limits specified in Table 1 to 400 mm dia (Dimenional
tolerances DIN 53479) 64 Air leakage testing
Air Jeakage testing of low and medium 743 All PPS material used hall be pressure ductwork is not mandatory under compatible and comply with DIN tJlis specification Air kakage testing of high 4102 part B and SS 476 part 7 class pressure ductvork t mandatory under this 4 PPS material should not be used for specification and for details of testing external applications vithout suitable procedure refer LO DW143 A Practical Guide protection (See Part 6 section 19) to Ductwork Leakage Testing
744 It should be noted thal PP is not fully 7 MATERIALS compatible wilh PPS
71 Application 75 FBPP (Forms aailable) This specification applies to ductwork constructed from materials as defined below 7 51 Sheet in thickness 3 mm to 9 mm or equal Minimum material thickness is to be taken a a nominal thickness as Tables 267 7 52 Continuous roll form in thickness 2 10 amp 11 AJJ UPVC materials ued shall be mm to 4 mm low flammability selfextinguishing compatible and UV stable with pigment colour to RAL 7 53 This particular material is specifically 7011 and DIN 4802 B 1 designed to be externally reinforced
with GRP (See Section 24) 72 Types
The materials covered by thi specification are 76 UPVCGRP abbreviated herein as foIlowsshy This is a form of composite lamjnate used (UPVC) Unplasticised polyvinyl chloride where improved mechanical trengtb UV (PPS) Self eXlioguihing polypropylene stabilisatiolJ or fire retardence is required (PP) Polypropylene (GRP) Gla s reinforced plastic 77 UPVCIFOAMJGRP (FOAM) Rigid polyurethane self FBPPFOAMfGRP
extinguiShing foam This is a form of composite laminate used (FBPP) Fabric backed polypropylene sheet where insulation andor support is required for
special applications 73 UPVC (Forms available)
8 DUCTWORK CONSTRUCTION 731 Extruded sheet in thickness 3 mm to AND JOINT SEALING
12 mm (Dimensional tolerances to DIN 7748) 81 Ductwork construction
The election of longitudillal cross joint and 732 V series tube in sizes 110 mm to stiffener types within the criteria laid dOT1 in
1AOO mm dia and fittings in siz~ Part 3 amp 4 shall be used as a minimum standard
9
DW154 Spet((icatioll for Plastics Ductwork
82 Joint sealing and sealants 8226 The joint mu t be held in po ition ror at leamiddott 5
821 General minutes A jig should be The integrity of the ductwork used jf nece-ltsary to ensure depends on the successful applicatioll that no twisting force i of tbe conemiddot t jointing metbod appl ied to th joint during
the period 822 Solvent cementing
Solvent cementing a atisfactory 8227 Once made the joint method of jointing circular UPVC should not be exposed to socket anu spigot or leeve joints a undue force for eight certain solvent based cement horn shy hour Tb full strength of geneously bond the PVC surface the jOjJlt is not achieved in providing uitabl joints Solvent less than twenty-four cementing i not practicable with PP hours because of its hioh resi tanc to solvents The procedure recommended OTE SOLVENT CEMENT JOINTING by the cement manufacnJrer should METHODS ARE TOT RECOMshybe followed but the following points ME DED FOR RECTANGULAR are important DUCT SECTIONS
[N ALL CASES S ALA MATshy8221 Clearance between ocket ERlALS MUST BE APPLIED
and spigot must be STRICTLY IN ACCORDA CE minimal because of the WITH THE MANUFACTUR ~RS
lirnited gap filling propshy 11 STRUCTIO SAD OSHH ertie of the cement ASSESSMENT
8222 Inside edges of sockets and 823 Hot air welding utside edge of spigot VC and pp a be welded by
shouJd be lightly chamshy Llsing the hot ga Ifil1er rod meUlOd fered ltmd thoroughly cleaned described helow
8223 Mating urfaces should be 8231 The welding gas can be cleaned using a proprietary nitrooen or compressed air solvent cleaner to remove and shltlll b fIltered free grease and slightly etch the from suspended water oil surface vapour and particulate
matter 8224 The cement should be
applied a quickly a 8232 The filler rods shall be possible to the socket and made from material to r pigot over the full area of compatible with the matshythe mating surface are eriaJ being welded should be taken to avoid the use of excessive 8233 Butt weld joints shall be cement bevelled to an included
angle of 60deg to 90deg and 8225 The posi liolling of the joint where po sibl welds shall
mUSl be achieved immedshy be fully penetrated from iately after the cement i both ide of the work applied aJld surplus cement removed
10
DW154 Specificatiol for Plastics Ductwork
8234 The joint face and the filler rod surfaces must be clean and grease fre and preferably roughened b shyfore welding In particular any deposited filler rod that is charred mu t be scraped away before additional runs are added
8235 The numbers of runs of fi lIer rod shall be sufficient to give a thiekne s of era s section of the veld at least equal to the thiekn s of the sheet
8236 Where high frequency park testing i specified lhi shall be undertaken in accordance with tbe weldshying in tmction handbook
Note A full descriplion of welding method is given in the Welding Institut handboo entitled Data on Welding of Thennoplastic Relevant BS amp CE Standards are prEN 12814-1 amp 2 prE 13067 and prE 13100-1
824 Completion of compo ite laminate joints Following solvent ementing or hot air welding of joints campi tion of any specified external laminate shall
carried out to maintain thebe
825
integrity of the construction (S 8227)
Gaskets These can be fabricated from various materials in the form of a pre-formed roll she t or trip applied between opposing faces of fbnced ross joints It i a visable to select material r commended by th ga ket manufacturer for the pecific appucation intended
PART 3
Rectangula ucts
9 RECTANGULAR DUCT SIZES
91 This specification covers duct size up to a rnLltimum longer ide of I -00 mm Duct size with an a peet ralio greater than 4 I ar not recommended Although they offer no problems of construction they increase friclionaJ resi tance and the pos ibility of Dois
10 CONSTRUCTION
101 General Th minimum constructional requiJement r r UPVC and PPPPS un-reinforced are hown in able 2
102 Longitudinal seams Longitudinal seams should Dot be located at corners or in the underside of the duct
103 Sheet jointing seams Seams shall be joined by continuous filler rod hot air welding or by fl1sion Vi ldiug only other form of jointing are not acceptable
104 Socket and spigot joints Sock t and spigot joints shall be formed by purpoe made double cket pi ces 100 mm long and of the ame thiekne material as the duct welded into position on each standard length of duet forming 50 mm de p sockets prepared and ready for final jointing on site with filler [Od of the ame formulation used for prefabrication (See Table 2)
105 Flanged joints
1051 FJa ges Fabricated flanges shall b con tmeted u ing miniumum of 9 mm thick by 50 nun wide material of matching formulation depending on duel size as hown in Table 2 The flange hall be mounted true and square to the duct surface and w lded on both sides a 103 and Figs 3 4 Alternative con truction Illay be
11
DW154 Spedjicfltiotl for Plastics Ductwork
utilised for attacllment to plant or other equipment
1052 Drillings Drjllings shall be placed to permit clearance to tbe extel11al casing and any reinforcement of tbe ductwork for the application of fastening
1053 Fastenings For nonnaJ application bright zinc plated bolts nuts and vashers hall be Llsed in sizes and pitch centres shown in Tabl 3 Where special conditions prevail consideration of other material finishes such as stainless steel bolpounds nuts and washers may be used In all cases gasket materials as Section 825 shaLL be used
106 Expansion joints Wher the configuration of the ductwork does not provide for movement due to temperature change or where such movement is restricted by branches or attachmenL expansion joints should be specified by the designer (See Section 18 FlexibleExpansion joint connections)
It is the re ponsibilir-y of the designer to identify the positions of any necessary expansion joints hased upon design param ters for the individual systems (See Figs 23 to 25 34 amp 35)
Design ote xamples of expansion joints shown in Figs 23 to 25 are not suitable for movement exceeding 30 mm
107 StilJeners
1071 External stiffeners Shall be fitted as specified in Tables 2 amp 10 and Figs 5 amp 6
1072 I temal stiffeners The u e of internal stiffening or bracing shall be acceptable iJ deemed necesary and approved by the designer (See Fig 7)
11 FITTINGS
111 Standardisation of fiuings The terminology and descriptions of rectangular duct fittings a et out in Section 25 are recommended for adoption as standard practice to provide common terms of reference for desi crners quantity surveyor and ductwork contractors and for those using computer in ductwork design and fabrication
Bend are designated as hard or easy and the e terms as used herein have the folJowin o
meanings
Hard signifies rotation in the plane of tb longer side of the cross ection
Easy signiiies rotation in the plane of the shorter side of the cros section
An example iIlu trating these term ] given in Fig 8
Fitting are fabricated by cutting and welding sheet
112 Stiffeners Shall be as 107 and Tables 2 amp 10
113 Splitters Shall be as shown in Fig 41 and welded as 1003
114 ruing vanes Where square bends are required turning vanes as shown in Fig 9 hall be fitted
115 Branches When fitting branch ducts to a main duct care should be taken to ensure that the rigidity- of the duct panel is maintained in terms of tbe sti ffenillg criteria
116 Change shapes Where a change bape is necessary to acconUllOdate the duct and the cross- ectional area is to be maintained the slope haU not exceed 225deg 011 any side (See Figs 52 to 56) Where a change in shape includes a local reduction in duct cras - ectionaJ area the slope should not exceed ISO on any side and tbe reduction in area should not exceed 20 Where tceper angles are necessary due to ile
12
DW154 Spec([icatirJ1l for Plastics Ductwork
restucllOn splitters shall be provided Taper Transformation pieces from circular 10 square pieces reducers and transformation piec s or rectangular shall be made as long a shall be manufactured from the tbickl1 s of p sible and uJe angl ball be uot mor than material specified for the larger size ducl 225 (Fig 55)
loon Pa 1500 Pa
2 3 4 5 6 mm mm mm mm
3 socket amp spigot - - -or tlanged
as Figs 1 2 3 401 to 600 45 flanged 50 x 9 flat 1200 800
50 x 9 flat welded both sides a Fig 3 as Fig 5
601 to 1000 45 flnged 50 x 9 flat 800 600 50 x 9 flat welded both sides as Fig 3 as Fig 5
1001 to 1500 6 anged 75 x 9 flat 600 600 75 x 9 flat welded botb sides as Fig 3 as FieJ 5
or or 70 x 70 x 9 angle 50 x 50 x 5 angle
as Fig 4 welded both sides as Fig 6
N t For constructional operating temp rature limits refer to Part 2 Clause 54
Longer Pitch Bolt Size
Side max 2
mm 1m mm Up to 400 100 8 with washers 401-600 tOO 10 with washers
601middot1000 100 10 with wash rs 1001-1500 100 10 with oycrsized
washer
13
Table 2 inimum con tructional requi ments - rectangUlar nmiddotreinforce UPVC and pp
Joints Sliffeners Maximum spacinOLonger Side MillirnUlll She t between
Thickness Joint~S(iffi ners
mm Up to 400
DW154 SpedflCiltion for Plastics Ductwork
Cross joint - recta gular ducts
Fig 1 Socket and spigot joint (UPVC and PP)
Conlinuou weld joint on sile onlinuou- wcld
CT~r~T2
Fig 3 Flange joint (UPVC and PP)
ontinuou weld
Fig 2 Socket and spigot joint (UPVC only)
Fig 4 Flange joint (UPVC and PP)
S iffeners - rectangular ducts
Fig 5 Flat Fig6 Angle
Oatim wo]
Fig8 Bends - examples of hardTie rod assembly and easy
Hard
Fig7 With spacers Easy
4
DW154 Speci(uariml for Plastics Ductwork
Fig 9 Turning Vanes
HOWl G TYl AL EXAMPLE OF FOCI G
15
Ma vane length shy 615 mm
Example ofbraemg when V1IIle length exeeed max pennined Ahematively two banks of ncs fixmg the centre rail together at ] 50 mm nrrcs
U~_II---- fixed to dnct wall both CDds
bLEVATION
vane
Maximum distance between centrc oflUming vanes should [Jot exceed 60 mm pitch
DW154 SPCCijicllfiull for Plastics Ductwork
practice to provide common terms ofPA T4 reference for designers quantiry urveyor and
Circular Ducts
12 CIRCULAR DUCT SIZES Th duct sizes [n Table 4 have been selected from the ISO and C standard ranges as the 132 preferreod sizes
Table 4 Circular ducts shystandard extruded tube sizes
133 Extruded tube
ISO Standard Sizes (Nominal Diameter) 11
Wan Wall Thickness Thickness
mm mm mm mm 110 500 4022
I25160 600 50 I25200 630 60
225 25 700 60 13425250 800 63
280 900 70 315
23 23 80
355 1000
25 1250 104 400 32 1400 108 450 35
Note The above sizes are subject to normal manufactl1ring tolerances Other size may be available in varying wall Lhicknesses and subject to test and operational pressure
13 CONSTRue ION
13 General Tllis specification covers duct sizes up to a maximum diameter of 1500 mm The minimum constructional requirements for UPVC amp PPPPS un-reinforced ducts sball be as Tables 6 amp 7
ductwork contractors and tho e using computers in ductwork design and fabrication The requirements for circular duct fittings apply throughout the size ranges covered in this specification
Sheet jointing seams Seams shall be joined either by continuous fLiJer rod hot air welding or by fu ion welding Other forms of jointing are not acceptable
Socket and Sl)igot joints Socket and spigot joints shall be formed by purpose made double socket pieces 100 mm long and of the same thickness material as tJJe duct welded into position on each tandard length of duct forming 50 mm deep sockets prepared and ready for final jointing on ite with PVC adhesive andor fill r rod of the same formulation used for fabrication
Flanged joints
1341 Flanges abricated flanges shall be conshy
structed using minimum of 9 mm thick by 50 mm wide material of matching formulation depending on duct size as shown in Tables 6 amp 7 The flange shall be mounted true and square to the duct surfaces and welded OD both sides a 103 and Fig 12
1342 Drilliogs Drilling ball be placed to permit clearance to the external casing and any reinforcement of the ductwork
1343 Fastenings For normal application bright zinc plated bolts nuts and washers hall
16
For srualler diameters preformed fittings are available otberwise fitting are fabricated from segments of duct or sheet welded together
The terminology and description of circular duct tiltings as set Ollt in Section 25 are recommended for adoption as standard
be used in sizes and pitCh centres shown in Table S Wh re special conditions prevail consideration of other material finishes such as stain le steel bolt nuts and wasbers shall be u ed In all ca cs gasket materials as Seciion 825 shall be USed
DW154 Speciliwriml for Plastics Ductwork
135 Stiffeners
1351 External stiffeners Shall be fitted as specified in Tables 67amp 1 I and Fig 13
1352 Internal stiffeners The use of internal stiffening or bracing hall be acceptable if deemed neces ary and appn ved by the designer
f 36 Expansion joints Where the corrfiguration of the ductwork does not provide for movement due to temperature
Cross joints - circular ducts
change or where such movement is restricted by branches or attachments expansion joints should be fitted (See Section 18 Flexible Expansion joint connections)
It is the responsibiLity of the designer to identify the position of any necessary expansion joints based upon design parameters for the individual systems (See Figs 23 24 2534 amp 35)
Design Note Examples of expansion joints shown are not suitable for movement exceeding 30 mm
Fig 10 Socket and spigot joint (UPVC and PP)
ConLinuous weld joim on ite Ontinuous weld
crlr~l
Fig 12 Flange joint (UPVC and PP)
Continllous wcld
boil
Continuous weld or Solvelll cement
Solvelll ccmcnl joim on sile
Fig 11 Socket and spigot joint (UPVC only)
Stiffeners - circular ducts Table 5 Fastening centres shycircular duct flange jointsFig13 Flat
flat conljnlJou~ly welded Diameter Pitch Bolt Size
max
1 2 J 11
1 shy -~
mm mm mm Up to 600 100 8 with washers
601middot1000 100 10 with washers - ---I
1001middot1500 100 10 with oversized washers
1
Minimum offourfixings
17
DW154 Specifiiutiofl for Plastics Ductwork
Table 6 constructional quiremen s - circular unshy inforced U VC
Diameter Minimum Joints Stiffeners Maximum spa ~in r
Sheet between Thickness Jointsl tiffcners
1000 Pa 1500 Pa
1 2 3 4 5 6 UD mm mm mm mm
UO to 600 3 socket amp spigot as Figs 10 11
or fla ged Fig 12
601 to 1000 45 socket amp spigot 50 x 9 flat 2400 2400 as Figs 10 11 welded bo sides
or Oanged as Fig 13 as Fig 12
1001 to 1500 6 Hanged 75 x 9 flat 1200 1200 as Fig 2 welded both ides
as Fig 13
Applies 10 Tables 6 alld 7
Note 1 For constructional operating temperature limit refer to Part 2 luu 54 2 To allow for conicleration or extruded se lions or fabricated component the materia] tllicknes i hawn a nominal
Table 7 Minimu onstrucfional requirements shy circular un-reinforced PPS and
Diameter Minimum Joints Stiffcners Maximum pacio Sheet between
Thickness Join sStiffener 1000 Pa 150n Pa
I 2 3 4 6 mm m m mm
110 to 500 3 socket amp spigot as Fig 10 or flaoged as Fig 12
501 to 750 45 ocket amp spi~ot
as Fi 10 or Uanged as Fig 12
751 to 1000 6 tlanged 50 x 9 Oat UOO 12 0 as Fig 12 welded nth sides
as Fig 13 1 1 to 1250 6 flanged 75 x 9 flat 800shy 800
as Fig 12 welded both sides as Fig 13
1251to~ flangcd 75 x 9 Oat 600 600 as Fig 12 welded both sides
as Fig 13
18
DW154 Sped(icalirm for Plastics Ductwork
PARTS
Hangers an Suppo ts
14 GENERA
141 Supports are an e sentiaJ part of me ductwork system and their supply and in tallation are normally the responsibility of the ductwork contractor The principl s are a I-rvCA publication DWIl44 Part 6 Section 19 and should be read in conjunction with this document
Design Note Designers may pecify specific requirements wbich will supersede guidance given in DW144
142 Rectangular ducts abl 8 give the- minimum requirements for
hanger and supports for un-reinforced ductwork
143 Circular ducts Table 9 gives the minimum requirements for hangers and upports for uD-reinforced ductwork
144 Vertical d cts The design of supports for vertical duct is dictated by site condition and where practical duc hould be upported at 4000 mm interval or where tbey pa s through a floor (but n ver exceeding 4500 mm) see Figs 17 amp J8
145 External ducts Where ducts are external to buildings and may be ubject to wind loading support should be plac d so as to restrain ide tl1ruSt and should allow axial movement as neces ary It is the respon ibility of me de igner to calculate the effect of the particular prevailing condition and to define any special upport requirement
146 Expansion joints Support shall be designed to permit axial movement only and shall e provided on eitl1er ide of expansion joint
I 1shy
I~
mm -Jp to 400
401 to 600 601 to 1000
Table B Hangers and Supports - rectangular horizontal ducts
Hanger Bearer Drop Roll Formed Rod
Long r Side
Cbannel ~-shy ~
---shy
Maximum ~pacing
4 52 3 _ -c Fig 15 - Figs 14 15 16 amp 2J
shy
mmm mmmm 240025 x 25 x 16 40 x 20 x 15 8 240040x20x15 40x 20 x 15 10 240040 x 20 x 1~510 40 x 20 x 15
shy
I
40 x 40 x 15 40 x 40 x 15 24001001 to 1500 I 10
Table 9 Hangers and Supports - circular horizontal ducts
Longer Side Hanoer Split Clips Maximum spacing Drop Roll f-ormed and Wrap-round Rod ~hannel Hang r
2 3 4I Fig 1920 amp 22Fig I
mm mmmm mm mm 25 x 25 x 15 IIp to 355 8 40 x 3- --1-_ 2400
2400
2400 2400
70x 6
40 x 5 SOx 5
40 x 20 x 15 40 x 20 x 15 40 x 40 15
10 10 10
356 to 600 601 to 1000 1001 to 1500
19
DW154 Spccijicutioll for Plastics Ductwork
147 Protection specification Any special coatingpaint Unless otherwise stated all support shall be finishes for protection against hostile manufactured in material as specified in this environments shall be advised by the designer
SUPPORT BEARERS
~ 14 Flg16 Inverted profile
angle I ~lIed steel
channel (alternatives) Fig 15 Profile channel (alternatives)
TYPICmiddotAL VERTICAL DUCT SUPPORTS Flat bar clipStiffening frame Outline ofinsulation stiffening frame or tlanged joint (if applicable) or flanged joint
Stiffening framc or flanged Joint
~~-I ( ee notes 10) I
r--~ -++- ~--4==J===4~---
Fig 17 Vertical rectangular ducts Fig18 Vertical circular ducts
The support bearer which depending on ducti tructural opening size could be either channel or angle section may be ll1ilised in any of the following arrangementsshy
a) To support the underside of a flat bar clip in halves (circular)
b) To support the underidc of either the stiffening frame oftbe flanged joint ofaoy duct section
c) To support either a stiffening frame Or a flanged joint below nsing drop rod srudding
20
DW154 Spediraiml for Plastics Ductwork
Arrangement of bearers and hangers (to be read in conjunction with Table 8 amp 9
wbich list material sizes relative 10 duel izes)
KEY Limits refer to actual duct size - insulation is additional - Typical
attachmentv -Atta hment t strucUlrcI to strucUlrc
I I
I - Flat Bar
I - Drop rod or - utlinc of lllddmg In ulillwn (if
applicable)
Alternative 7 drop rod or rt------------ 1 studdmg q I
I I Rectangular
ii i n 1
Fig 21 Rolled or profiled bearer Limit oncFig 19 Wrap-round hanger Limit 55 DIA
V v Drop rod orAllernaUC 1 1 tudding
drop rod or 1
-- -- 1studding and elded bas 1
I I0 -_
Limit 355 DIA Frg 22 Split clips Limit 1500 DIAFig 20 Flat strap hanger amp split clips
21
DW154 Specification for Plastics Ductwork
6PA deElned in J62 appropriate to the airflow pressure acoustic temperature and corrosion
General
15 ACCESSl SPECTION OPENINGS
151 General These are for inspectionservici ng on 1y
HVCA publication DWIl44 Part 7 - General Section 20 sets out the requirements for access applicable to this specification
152 Cleaningmaintenance Designers shall take specialist advice and then stipulate their requirements for the periodic internal cleaningmaintenance of ductwork and of the consequent need for adequate access for specialist cleaning equipment including the size type and locationfrequency of the actual access openings required
Appendix D sets out guidance notes for the consideration of cleaning access and also makes reference to the HVCA publication TR 17 Guide to Good Practice Cleanliness of Ventilation Systems which covers the su~ject
in greater detail
Note A majority of in tallations in which plastic ductwork is used are considered to have a nigb operational risk potential and provision of access should address this
16 REGULATI G DAMPERS
161 General Balancing dampers and control dampers are elements inserted into an air di tribution system or element of an air distribution sy middottem Balancng dampers permit modification of the air resistance of tbe system and consequently cbanging of the airflow rate Control dampers control tlle airflow rate and may in addition provide low leakage closure of the airflow
The deigner shall specify damper locations taking into consideration that good design practice requires a minimum of five times the diameter or width of the shortest side of uninterrupted flow between plant connections and the damper and select the damper type as
characteristics
1611 Balancing damper To achieve the required distribution of air in the ductwork system at inlets andor outlets for [hi purpose the damper blades are set and Jocked manually in position between fully open and fully closed
1612 Control damper To secure dynamic control of the air now in the ductwork system In thi function the damper will always be power actuated and may require to be modulated between fully open and fully closed and to be capable of taking up any position between these extremes In the fully open position the damper should have a minimum pressure drop In the fully closed position it will not necessarily achieve a complete shut off
162 Types of airflow control dampers Airflow dampers of various types are available for specific purposes as follows
1621 Single - blade dampers Single-blade dampers shall consist of a si ngle pi voted blade cOlllained withjn a casing or section of ductwork The blade shall be adjustable tbmugh a nominal 90 angle by means of a quadrant or similar operating mechanism Where automatic control of the damper is required the spindle shall be extended to enable a powered actllator to be mounted
Single-blade dampers shall have a maximum duct width of 400 nUll and a maximum duct height of 400 mm for rectangular ducts and for circular ducts a maximum diameter of 400 mm
1622 Multi-blade dampers Multi-blade dampers shall consist of a number of pivoted blades contained within a casing The blades shall be
22
DW154 Sedicalirm for Plastics Ductwork
adju table through a nominal 90deg angle simultaneously by intershyconnected linkage or gears connected to a quadrant or similar operating mecbanism Where automatic control of a damper is required a spindle shall be extended to enable a powered achlator to be mounted
There is no restriction on the size of duct in which multi-blade dampers or damper assemblie may be u ed Where dampers are required for blade lengths in excess of 750 mm the blades should be suitably reinforced or supponed 0
individual damper blade should exceed 200 mm in width
1623 Iris dampers Lris dampers shall consist of a nUlllber of radialty interconnected blades which open or close within a casing with duct COlll1cctions The blade shall be simultaneously adjusted by a quadrant or similar operating mechanism
Iris dampers shall be installed as specified by the manufacturers operating and installation instructions where the product is unidirectional with regard to airflow
lris dampers are available for circular ducts only in diameters up to 250 mm (it should be noted that the damper casin i appro)(imately twice the diameter of the duct)
1624 Backdraught dampers Air pressure operated uni-directional rectangular (single or multi-blade) with adapters if fitted to circular ducts
1625 Slide and blast gate dampers A damper [lsed as a shut off facility with an externaJ Lide bousing allowing the blade configuration to be fuJly inserted to fully extended for maxiDlUlll air flow
163 Construction
1631 Materials All products shall be protected against cOHosion as necessary and supplied in a fully finished condition as specified by the designer
1632 Dampers used in low and medium pressure systems The following recommendations apply to dampers forming an integral part of ducrwork with pressure classifications A and B air leakage limits
The dampers shaH be constructed to minimise distortion and prevent jammin in operation Th blade shall be sufficiently rigid to minimise movement when in the locked pOSitiOLl
The blades shall be securely fixed to the operating mechanism All balancing dampers shall have a locking device located on the outsid of the case and shall giv clear indication of the actlwl blad position All penetrations of the duct shall be fitted with suitable seals where necessary
1633 Dampers used in high pressure systems Regulatino- dampers used in duc[work sy tems to pressure cJassification C shall meet tbe construction requireshyments specified in 1631 and 1632 with operating mechanisms out of the air-stream
1634 Proprietary types of damper The use of any specific type of proprietary damper shall be confirmed by the designer In all cases proprietary dampers shall meet the relevant requirements of thi specification
1635 Damper casings Duct damper casings hall be constructed to meet th mllllmum
23
DW154 SpeciJimlioll for Plastics Ductwork
leakage Iim its sp cified for th c1uctwork ystem to which tbey are installed
In order to apply the square metre leakage calculatio as detailed in DW143 A Practical Guide to Ductwork Leakage Testing the reference casing area ball be taken as the perimeter ize of lh damper IDultipli d by the equi alent length of Imetr eg an 800 mm x 400 mm duct damper hall have a surface area for casillg leakag p donnan calculated as follow (2 x 08) + (2 x 04 x I
=24m2 casing area
Other pelforlllance ancl rating test methods for damp f and valves are specified in ISO 5129 and BSIE 1751 and are referenced belm a) Leakage past a closed damper
alve BSIE 1751 b) low ratepre sure requirement
characteri t cs BSIE 1751 c) Operational torque le ring
BSEN 1751 cl) Thermal transfer testing
BSIEN 17 I e) Reg nerated sound power levels
ISO 5129
164 Installation Dampers shall be imaalled in accordance will) any re Ievant ISO EN or British Standard 10 aJ bUT lcling regulation and national code of practice as well as the manufacturers recommendations
17 FIRE DAMPERS AND INT MESCENT SLEEVES
171 General Damper or sleeves arc requiTed on duct y~telll where the designer has -tjpulated the
duct wiU penetrate a fire compartment in the majority of application tbermopla ti ductwork is ugtecl where contamlDated corro ive or otherwise exceptional fumes are concerned it is preferable to use tire damp r which are externalJy mounted ie of the intmnescent operated crush typ
24
72 Fit-e rating The damper assembly should have a fUT
resi tance ratin o equal to that of the fir ban-jer it penetrate and ball be fire tested and rated to the timetemperature curv of B 476 Part 20 and 22
173 Intumescent sleeve At the time of writing this specification qualified test results were available for rectangular dampers and circular dampers up to 55 mm diamet r Manufacture have indicated that they are able t provide speci fications for other size and diameters This infonnation should be confirmed b th de igner Various type are available includino
tho e incorporating ruechanical closing plate and those operated anI by expanded iJllUme c nt media
In all ca es fire damp rs and intnmeBcen leeves shall be supplied and in taUed in
accordance with the manufacturer iJlStructioos and COSHH a essm nt
174 Other types Fire dampers of mious types are availabl for specific purpose~ ee HVCA publication DW144 The de igner should )lot (hat materials for con lt1Jction bould be uitablc for the par1icular application
ALL C SES FIRE DAMPERS AND fNT MESCENT SL _VES SHALL HE S PPLTED AND INSTALLED IN A ORDA CE WITH Tf--IE MANUshyPACTURERS STRUCTTONS AND COSHH ASSESSMENT
18 FLEXIBLEEXPANSION dOINT CONNECTIONS
181 General ploperties Tbe material u ed for flexibleexpan ion iojnt~
mu t meet the design r requirements for temperature air pressllrelfe resistance applicable to pl astic duct sy tem vibration and noi e br akout when incorporated into a jointconnection and shall comply ith lh standard of air-tigbtne specifi cl for the duct work sy tem of which it fOlms part (See Figs 23 24 5 26 27 amp 28 for typical con truclion clelai Is
DW154 SJecilimtol for Plastics Ductwork
Expansion joints
Fig23 Moulded bellows type (rectangular and circular)
Fig24
~F aiblc sleeve
__ liding sleeve
~~~~
Sleeve type (circufar)
Fig 25
AIRFLO
COnlinuou~
weld~
Flexible Iceve
PV A HOWN pp SE BACKING FLATS AS FIG 2
Sliding lee c Co1linuou
weld
Flanged sleeve (rectangular and circular)
25
DW154 Specificatiol for Plastics Ductwork
Flexible con ections
Fig 26 Flexible sleeve with clips (UPVC and PP)
--__ Flexible I eve
I
I
I CODn clioD to plant ~
Band clip
Fig27 Welded flexible sleeve (UPVC only)
Plastic)sed PVC slceve ~-- onll11uo1sly welded
onrreclion to planl ~
Fig28 Flanged flexible connection (UPVC and P )
t sp dally moulded flexible flanged connCClitlll
boil
C)nneclion to plant ~
26
DW154 Specificotiol for Plastics Ductwork
182 LOClt1tion Flexible joint are typicltllly lIsed at building expansion joint and fan inletsoutlets Any others required should be indicated on the de ign drawings Care should be taken to maintain alignment across jointsconnections
183 Length Flexible Jomts shall be kept as short as pra middottieable above a minimum eft ctive length of SO mm In no ca e shall a flexible joint exceed 250 mm in lengtb
184 Connections to rectang a ducts With flanged rectangular connections Ule tlexible material shall be held in pLace with flat pIa tic strip of not less U1an 6 mm thick ltlttached to the flanges using uitabJe fixings The more heavy weight type of fleAible mateLial may also be obtained formed into a channel ection with corners fitted to give a neat air tight j int For pigot connections the Be ible material shall b held in place with flat pIa tic trips n t less than 6 mm thick
t 85 Connections to circular ducts With tlanged circular connections the flexibl material shall be held in place with flat plastic backing strips or proprietary clip bands with screw or toggle fast ners
186 Welded flexible connections (Rectangular and Circular) Where the parent and llexibl material are from imilar ba ed products they can be joined to the duct u ing the welding method described in Section 823
19 PROTECT VE FINISHES
191 nles otherwise stated all ductwork shall be mallllfactured in mat fial as pecified in tbis specification Any special coatingpaint fmishes to be provid d by the duct work contractor sball be advisd by th de igner
20 CONNECTIONS TO BUILDING OPENINGS
201 Fanning and finishing building op nings are not the repoJlsibjlity of the duftw( rk contractor and the note that follow are for guidance purpo e only
2011 Openings in brick block or concrete walls shall have inset frames to provide a suitable means of fixing grille louver masking flanges or the tlanged ends of ductwork The illset frames shall be conslnlcted to maintain the structural int grity of the wlll and where applicable cavities shall be suitably lined
2012 Openin s in dry linino partItIons shall have inset frames a 2011
2013 Openjngs in cladding walls and roofs shall have flaoged leevesframes to provide a suitable means of fixing a 2011
2014 Horizontal and vertical opening xposed to oLltside atmo phere hall
be provided with a suitable weathering fini h at the external face especially where profiled cladding is used
2015 Timber framed op nings are not permitted In fj re compart ment barriers
202 Ductwork connections to building openings hall have a flange of suitable profile to permit practical fixing to the openillg frame In selecting the profile consideration shall be given to Tabl~s 2 and 10 in this specitication relating to duct ize and rating Gasket strip or sealant shall be ltlpplied between the tJaoge and building op ning frame
21 DISCHARGEEXHAUST TERMINAL
21 Tbese shall be vertical open ended and designed to meet and comply with current r gularions on contaminated flue The designer hall ensure that the de ign and perf rmance i suitable for its intended purpose Examples of some typical terminal designs are SbOiD in Figbull 102 10 bull 104 amp 105
27
DW154 SpedjimioTl for Plastics Ductwork
22 THERMAL INSULATION
221 The provision and application of thermal insulation to ductwork is not the responsibility of the ductwork contractor
222 Where ductwork is required to be preshyinsulated the specification should be agreed with tbe designer
223 Where the temperature of the air within the duct promotes condensation on the exterior surface of the duct and cause moisture penetration througb the thermal insulation vapour scaling may be required and in this case the most important requirement is to limit penetration of the seal
The extent of any vapour sealing of ductwork thermal insulation and the support method to be u ed must be clearly pecitled in advance by the designer
224 For detailed information on the thermal insulation of ductwork reference should be made to BS 5422 1990 which covers the specification for thermal insulation materials on pipes ductwork and equipment (in the temperature range -40degC to +700degC) and BS 5970 1992 which is a Code of Practic for Thermal Insulation of Pipework and Equipment (in the temperature range -lOOdegC to +870degC)
23 FIRE RETARDANT FINISHES ON PLAST C DUCTWORK
231 The designer should note tbat ductwork constructed to DW154 has no teted fire rating or information see Appendix C
24 REINFORCEMENT OF DUCTS WITH GRP LAMINATE
241 General Where ductwork is required in larg T izes than are covered by Tables 2 4 6 amp 7 or with the increased strength sometimes necessary for industrial use external reinforcement is normally pwvided by applicatioD of glass fibreresin laminate
GRP systems will bond satisfactorily with standard UPVC sheet but for pp it is
nece sary to use a specially prepared sheet with a glass fabric backing incorporated dOling manufactllfe
The detailed techniques of fabrication using GRP are outside the scope of this speci lcation but the following notes are offered for guidance of ductwork fabricators
242 Materials
2421 Quality The laminate is made up of polyester resin complying with BS 3532 and glass fibre complying with BS 3496 or BS 3749 The nominal ratio of resin to glass fibre should be 7030 by weight
2422 Minimum properties The laminate shall comply with the followiog mini mum pbysical properties
Tensile strength - 70 MNm Tensile modulus - 7 Gl m Flexural strength - 140 M Im Bond strength (hetween laminate and substrate Not less than 7MNm Bmcol hardnes Not le s than manufacturers specification
The GRP reinforcement educe the expansion of the parent material but the resultant stre ses arc well within rhe strength of the bond However the Iinear thermal expansion curve shown in Figs 34 amp 35 will serve as a guide
Surface resistivity electrkal propcltles and acoustical propertie are similar to the relevanl unreinforced materials The fire retarding properties of GRP may be improved by the use of specialisl laminating resin
2423 Forms available GRP Laminate should be built up from the separate materials ie resin aod glass fibre in the form of chopped
I strand mat or spray ravings
28
DW154 Spcification for Plastics Ductwork
2424 Workshop conditions Polyester resuls are sensItIve to lmperature and the workshop hould b maintained at a temperature of herween 20deg and 25degC HiOh relative humidities and damp onditions should be avoided A good rate of air change must be pro icled pJeferably by m chanical ventilation
2425 Storage of materials Resin and urin o agents shouJd be stored in dark cool condirions away from the working area and in confonnit with statutor requireshyments for tJle middottorage of flarmnable liquid Because of Ule Limited torage lif of the unmixed resin and curing a eot mal lials ~hould be ch eked before use to enLlfe that they are within the manufacturer pe ified sh If life (usually ix month from the dm of manufacrure)
Glass fi re should be stored separately und r clean dry conditions
243 Surface preparafon
2431 UPVC To achieve the specified bond strengtll the urface to which the GRP is applied mut first be thoroughly cleaned and then etched either by mechanical means or by the use of a suitable solvent
2432 pp with glass fabric backing To achieve the specified bond middottrength the fabric backing must be thoroughly impregnated Witll resin
244 Mixing the materials for use The re in 1 a three part mix compri lng base I sin hardener and accelerator The manufactur rs pecj[ied proportions are critical and th llUxmg sequenc pecified must be meticulously foUowed
The resin has a very limited life after mixing and before u e It is dependent on the characteri tics and bulk of th resin the alllount of hardener the degree and method of acceleration and the workshop onditions
245 Methods of application
2451 General The mixed resin may be applied by hand or b pray c1epoition The operation must b completed within the gel time of th y tern and tbe laminat fully cOI1olidated to achi v the phy ieal properties pecified
2452 Hand lay-up The duct surface i coated by hand with resin Llsing a brush and a mar of gla fibp orked in until full consolidation achieved Th proc is repeated untiJ th requird thicknes i obtained
2453 Spray depo Won The duct surface is coated WiUl re in by spray gun with the chopped glass roving added through a separate nozzle The full thickne i obtain d in layer with con olidation of each layer by hand roller
246 Construction
2461 General M ini mum COllst ructional requireshyments are pe itied ill Tabl 10 for rectangular and Table 1J for circular dUClS
2462 Joints and stiffeners Fig 29 30 31 32 amp 33 hoI TOSS
joint and tiffener for reinforced UPVC and PBPP duct
247 Worki g practices The fabrication of ductwork pecifiecl ill thi document i not affected by the addition of GRP
29
DW154 SfJcdJicatiOt for Plastics Ductwork
Table 10 Minimum constructional requirements shy
Longer Side Minimum Sheet Thicknes and
GRP Reinforcement
UPVC FBIPP 1 2 3
mm mm mm Up to 1000 3 plus 3 plus
06 kgm2 06 kgOIl GRP GRP
1001 to 2250 45 plus 3 plus 06 kgm 12 kgm
GRP GRP
2251 to 3000 45 plus 6 plus 12 kgm 12 kgm
GRP GRP
Cross Joints
UPVCFBPP 4
mm socket amp spigot
as Fig 30 or flanged as Fig 29
75 x 9 flange welded on both sides as Fig 29
75 x 9 tlange welded on both sides as Fig 29
rectangular GRP reinforced ducts
SlifTeners Maximum Spacing Between
JointsSljffeners UPVCIFBIPP UPVCFBPP
5 6 mm mm
75 x 9 flat 800 as Fig 31 or
50 x 50 x 5 plastic or MS inverted angle as Fig 32
or tormer as Fig 33
75 x 9 flat 600 as Fig 31 or
50 x 50 x 5 plastic or MS inverted angle as Fig 32
or former as Fig 33
75 x 9 flat 600+shyas Fig 31 or 50 x 50 x 5 plastic
or MS inverted angle as Fig 32
or former as Fig 33
Note 1 On rectangular duct up to 400 mm longer side no stiffeners are required 2 Applies to Tables 10 amp I I For COlJstructional operating temperature limits refer to Part 2 clause 5A 3 Tables 10 amp II apply to all pres ure classes up lo ]500 Pa
Table 11
Diameter
1 III
lJp to 1000
1001 to 1750
1751 to 2500
Minimum Sheet Thickness and
GRP Reinforcement
UPVC FBPP 2 3
mm mm 3 plus 3 plus
06 kgm 06 kgm GRP GRP
45 plus 3 plus 06 kgm2 18 kgm
GRP GRP
6 plus 6 plus 12 kglm2 18 kgm1
GRP GRP
Cross Joints
UPVCFBPP 4 III
socket amp spigot as Fig 30 or flaoged as Fig 29
75 x 9 flange welded on both sides as Fig 29
75 x 9 flange welded 00
both sides as Fi 29
inforced ducts
Maximum Spacing Between
JointsStiffeners UPVCIFBPP
6 mm 2400
800
600
Stiffencrs
UPVCFBPP 5
mm 50 x 9 flat as Fig 31
75 x 9 flat as Fig 31 or former as Fig 33 75 x 9 tlat as Fig 31 or t()rmer as Fi 33
ote On extruded tube tip to 600mm diameter no stiffenergt are required
30
DW154 Specificatioll for Plastics Ductwork
G - Cross joints and tiffeners
Fig 29 Flange Joint Fig32 Stiffener shy inverted angle
M artiPfCuQkbdd erttpObri) Wl111 RP tlddtlt
_- GRPloliu] lh~
Fig 30 Socket and spigot joint Fig33 Stiffener shy use of former
Fig 31 Stiffener Flat
I Pv FlPP ~ ~lmJaDUA1) d
OMrlQ rrnall 1( tQlS
25 STANDARD COMPONENT DRAWINGS AND ABBREVIATIONS
251 The illustrations in this section not only highlight where applicable geometric limjtations for the de ign and manufacture or ductwork components but also recommend
standard drawing representation terminology and abbreviations for both duetwork components and some of the more commonly used ancillaryplant items
252 Designers and surveyors should note that bills of quantities should provide a full description
3)
---
v
DW154 Spcc(fim(ml for Plastics Ductwork
Fig 34 Linear Thermal Expansion
u c 0 N ro 0)
b 0)
S
sect0
5 oS cl) 0)
~
on ~ ltl
c U
-30 -20 -10 0 10 20 30 40 50 60 70 80 90 TEMPRATURE C
~ V
-
~~c_ ~
~V
V ~
-7 ~
-- ~V ----
v
-6
+14
+12
+10
+8
+6
+4
+2
0
-2
--4
ig 35 Typical Design Stress tor UPVC and P
7
6
r shy 5E
-c E----0 4t) VJ 0)
ci5 0Jl 3
~
0)
Cl
2
1
o
UPVC
1
000
1
1
pp
- r-- shy r----- shy - t--shy I
__0
-30 -20 -10 0 10 20 30 40 50 60 70 80 90 TEMPERATURE C C
Note Figso 14 amp 35 shaded area refers to GRP reinforced duct
32
DW154 Speciicfltirm for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - REC ~NGULAR
Splilt~r Posilion W-mm pliucr
A B c 40]--QOO 1 W - -
601-1000 1 W4 Wf2 -
1001-1800 3 WI W3 W2
FIG DRAWING DETAfiS
tU]36 ATI Straight Duct with socket and spigol joint
rn [037 Straight Duct with flanged joints
[I []38 Straight Duct with flanged joints
rkJ Short Radius Bend
39 Applies to any augl and for duct up to 400 n11n wide
Minimum (I1m31 radills = 100 mm
Medium Radius Bend (a illustrated)
[kJ Applies to any angle
40 Long Radiu Bend Similar but radius = W
Throlll radius = W2 Applies to any angle
- Short Radius Bend with plitlers
I -shy -shy u co - t lt Li--_ 41 t 0 ~ I I I
~ I
L 1W
Minimum waal radius = 100 mm Splitters not required in bend angle less than 45deg
42 QJ1 Square Bend with turning vanes ij
3
DW154 SP(L~ficatioll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - RECTANGULAR
FIG DRAWl G DETADS
43
~
I v
L L Radius Tee with internal deflectors
44
~ Radiussed Twin Bend
45
Imiddot
er Swept Branch
46 U-
Sqoare Tee with Turning Vanes
47
~ f
Breeches Piece
48 0 y l Piece
34
DW154 Specificatioll for Plastics Ductwork
STANDARD COMPONENT RAWINGS - ECTANGULAR
55
54
51
50
53
52
49
FIG
~MX
RAWlNG
DmiddotMAX
EfjMAX
Minimum throat rndius = 100 mm
Rectangular shy Round Transformatioll
Eccentric Taper 225deg max in either plane Spliller are required for angles greater than 225deg and hould bi eet the angle between any side and duct centreline
DETATLS
Angled Offset
OUset Taper Splitters are required for angle greater than 22 0
and shoold bi eet the angl between any side and dUCI centrelinc
Mitred Offset
Concentrk Taper 2250 max in ither plane SpUtters are required for angle greater than 225deg and should bisect the angle between any side and duel c ntreline
Radiussed Offset
35
DW154 Splcilcuthm for Plastics Ductwork
STANDARD COMPONENT DRAWINGS ~ RECTANGU AR
Branch ducl DimCllsions widlh (W) (A)
urnl mm up lO 200 75
300 100 400 125 600 150
Ocr 600 200
FIG DRAWlNG DETAILS
56 poundplusmni~~ Rectan~lar - Flat Oval Transformation
57 [ Square Branch
58 er Angled Branch
Branch dUCI Dimensions wfdth (W) (A)
[- mm mm59 3shy Shoe Branch Up (0 200 75
--shy AIshy + 300 100
400 125
450 MAX 600 150
Over 600 200
Branch duct DimensIOn
rP X width (W) A)
60 - 1--shy _
~ mm mm
Bell Mouth Branch pto 200 75 300 100 t 400 125
600 150 Over 600 200
0=0 61 -
~ Bell Mouth
- shy T 4-5deg M x
--I 1-shy
TJ
62 X I ] I
Tele-scopic Joint I Illustrated with flangeL
X63
SBD Single Bladed Damper
36
---
DW154 Spedicatioll for Plastics Ductwork
STANDARD OMPONENT DRAWINGS - RECTANGULAR
DRAWING DETAILSFIG
64 on-Return DamperNRD shyshy
shyXbull
Multi-Leaf Damper Can be piggoted or flanged oppo cd or parallel blade
Alternative controls areshy
q p [gtshy
J HD65 Hand
~MD otori ed
PO Pneumalic
L-lt
l 13G 66 Blast Gate DamperX X
FireSmoke DampersSleeves
211r Ratinggtshy----
L_-
---
----
r----
Ir-- shy
IL- _-l
2hr
With i tallation frame
67 41 r Rating
4hr
Smoke damper SD
Intumc cent Sleeve L-d
37
DW154 Specijicutiolt for Plastics Ductwork
FIG
68
69
70
71
STANDARD COMPONET DRAWINGS shy REC ANGULAR
DRAVING DETAILS
gtshy Access Openings
AP 6 Access Panel - Rerno able
w [ ~ Access Door - Hinged
I ~le Inspection Cover
le -I reg -lt
~X X Flexible Connection
~ Drop Cheeked Radiussed Twin Bend
U Drop Cheek Bend
I
72 Air Flow SymbolX
38
DW154 Specifim[ioll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - ECTANGULAR
FIG DRAWING DETAILS
73
74
75
76
77
Q
Q
rp---t
~
V- I Ir---I
JL --11
THE ABOVE DETAILS TYPICAL PLENUM
Air Terminal Plenums
Plenum with side connection
Plenum with top connection
Cover plate with connection
Special plenum with connection
elescopic conn ction in direction of air flow
39
DW154 SpecijicotiOll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG
78
79
80
81
DRAWING
-23~---pound3-(MALE) (FEMAJE)
-t=j--_j(--d-shy
--L
~ THROAT RADI S= D AS T NDARD
e ~
THROAT Rjf)lU = D A MU)
DETAILS
Straight Duct With male and female connectors
Straight Duct With flange joint and slip joint
Bend MouldedIFormed Applies to any angle ego 30deg45deg60deg90deg Medium radius bend as illustrated Long radius similar but throat radius 0
Segmented Bend 90deg four section minjmum as illustrated
Other Angles 60deg = 3 sections 45deg = 3 sections 30deg = 2 sections
I
i
40 shy
DW154 Speciicafinll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG DRAWING DETAlLS
82 Segmented Twin Bend Radius = D2 max
May also be fabricated from tube
83 Equal Tee MouldedIFormed
84 -~ 1in Bend MouldedIFormed
85 Taper Concentric 1 0 as iUu trated Eccentric 30deg iJJcLuded angle
86 Short Taper
41
DW154 SpcUicatol1 for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG DRAWING DETAILS
87 30 max Offset
Angle Branch
Bran h dUCI Dimcnsions dia (D) lA)
Shoe Branch mm mm 88 Cl
Off rectanguJur Up 10 200 75 lOO 10 400 125
- 00 150 Over 600 200
Bl1IllCh duct DimenlOns din (D) (A
~-$a-Conical Branch mm mm
89 Also acceptable with Up 10 200 r
full conical surface 300 10
400 125
END VrE -shy 600 150 Over 600 200
90
m 75
100 12 150 200
mm Up to 200
_ 300 400
600 Over 600
iUtred Branch
Shoe Branch
J-L----U ~ Bell oulh Branch
ENDV1EW
93
92
91
42
DW154 Specificatiol for Plastics Ductwork
STANDARD OMPONENT DRAWINGS - CIRCULAR
FIG
94
DRAW G
I
~ 30deg 090deg
Breeches Piece
DETAILS
95 amp-----~ Blank End
~-----p Multi-Leaf Damper Can be piggolcd or fianged opposed or parallel blade
Alternative controls areshyri=-+- L-T~
I
---
LT~
I r- -
-+1
J HO Hand96
bMD Molori cd
PD Pneumatic
tl-shy bull
Single Bladed Damper 97 ~ saD
on-Return Damper Vertical application only 98 m~D
43
DW154 Sf1tcificatioll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG
99
100
101
102
DRAWING
$ I-
2hr
1 4hr
SD
~v I I
CO TINENTAL COWL
DETAILS
Iris Damper
Fi reS moke Dam persSleeves
2hr Ratillg
With installation frame
4br Rating
Smoke damper
Intumescent Sleeve
Access Openings
Access panel - removable
Access door shy hinged
fnspection cover
Discharge Continental Cowl
44
DW154 Sp(Cii(ltJll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
DRAWINGltIC DETAns
-
I
I
~
I I I High Velocity Discharge Terminal 103 I
I
I I
J I I 1 ~--
Offset Stack Discbarge Terminal 104 1
~ I e --(-
I
N
I
I
I~
I I Vertical Oischarge with Weather Cowl 105 I
--1--1 I
I
GAPI I
RTl AL DISC) lARGE WITH W ATIIER COWL
45
DW154 SpecUicatoll for Plastics Ductwork
STANDARD COMPONE T DRAWINGS - PLA TEQUIPMENTIMISCELLANEOU
FIG DRAWING DETAILS
106 ~~~ Rectangular Attenuator
107 ~- Circular Attenuator
108
~ Beod Attenuator
109 J ~(f) Heating Coil
110 J ftte Cooling Coil
III Jc[ Electric Heating Coil
112 X F
Humidifier
113 [H XX Axial Fan
114 ~fB1famp Noo-standard Ductwork Cross hntchillg (of any separate type) indicates by reference to a key any non DVil54 ductwork system
115 2llIIIIJIIIIIll Flexible Ductwork
46
DW154 SJeCUicll(iol1 for Plastics Ductwork
TABLE 12 - STANDARD ABBREVIAT ONS
ABBREVIATION FLL
AD Acces Door
AFF Axial Flow Fan
AHU Air Handling nit
All Aluminium
AP Acess Panel
AT Attenuator
AV Air enninal Unit
BE 81ank nd
BQ Blast ate Damper
CC Cooling Coil
CF Centrifugal Fan
CTA Cross alk Attenuator
CVU Constant Volume Unit
DP Drain Point
EEC Electric Heating Coil
El Expansion Joint
FAl Fresh Air Inlet
FA From Above
FB From Belo
fBPP Fabric Backed Polypropyl-ne Sheet
Flexle Flexible Connection
lexfD Flexible Du t
C False Ceiling CO an oil Unit
fD Fire Damper
FFL Finished Floor Level
FJ Flanged Joint
FOAM Rigid Polyurethane Self xtinguishing Foam
FOB Flat on Bottom
FOT Flat on Top
GAM Galvanised after ManufacttrJc
GRP Glass Reinforced Plastic
GSS Galvanised Sheet Steel
HC Heating oil
HD and controlled Damper
HH Hand Hole
HL High Level
HVD High Velocity Discharge
IC Inspection Cover
ID lri Damper
IFS Intumescent Fircleevc
47
DW154 Specification for Plastics Ductwork
TABLE 12 - STANDAR ABBREVIATION CONTINUED
ABBREVIATION
IU
L
tv1D
MS
NRD NTS
OBO
OE
PHD
PD
PP
PP
PRD
PVC
RFC
RSC
R
SBO
SO
S1 TST
SSL
TA
TB
TO TJ
TP
TV
TV
OS
UPVC
S
V
VAV
50 RSA
FULL
Induction Unit
Low Level
Motor controlled Damper
Mjld Steel
on Return Damper
at to cale
Opposed Blade Damper
Open End
Parallel Blade Damper
Pneumatic controlled Damper
Polypropylene
Self xtinguishing Polypropylene
Pressure Relief Damper
Polyvinyl Chloride
Rolled Form Chamlel
Rolled Steel Channel
R fUnit
Singl Blade Damper
Smoke Damper
Slip Joint
Stainl t el
tructural Slab Level
To Ab vc
To Blow
Top Down (In Direction of Flow)
Telescopic Joint
Test Point
TU111iog Vane
Top Up (In Direction of Flo )
Voles Otherwise Stated
Unpl3sticisecl Polyvinyl Chloride
Underside
Ultra Violet Light
Variable Air Volume
Rolled Steel Angle (Vith Size)
48
DW154 SJeriiflllioll for Plastics Ductwork
A2 DUCT PRESSUREAPPE DXA Ductwork con truct d to DWIl54 will bebullbullbullbullbullbullbullbullbullbullbullbullbullbull
Air Leakage From Ductwork To be read in conjunction with DW143 A practical guide to Ductwork Leakage Testing
CAUTION As highlighted ill both this docul1lenr and DW14 I lot ellough emphasis can be placed 01 the fact that except for high pressure class C the much more stringent ductwork constructional standard brolght about b the general acceptance of DW154 have irtlally negated the requirement for leakage-testing It is essential lO realise lhat except where it is mandatory this doclllllelll is nOl an endors ~lIlent of the rourine testing of ducts bllt purely a guide to outline the procedures for cononnity with the air leakage limits ill Table l Where the specified methods of assembly and
A3sealing of dlcls are u ed a vi ual inspection wil ordinarily sl~fll e for ver(iatioll of a well engineered and a ceptahfy airtight COl1strucrioll WHERE NOT MANDATORY DUCT LEAKAGE TESTING IS GENERALLY AN UNJUSTIFIED AND SUBSTANTIAL EXPENSE
A1 INTRODUCTION L akage from ducted air distribution systems is an Lmportant consideration in the design and operation of ventilatjon and air conditioning middotystems A ductviork t)ystem tbat ba limited air leakag within defiucd limits wiH cnsUft
that tile design characteristics of the sytem can be maintained It wilJ also ensure that energy and operatLonal cosb are maintained at optimum levels DucLwork constlucted and Ulstalled in accordance with DW154 should minimise a level of air leakage that it) appropriate to tll operating static air pre sur in tile system
A4However it is recouuised that tbe environment in wtJich middotystems are installed is not always conducive to achieving a predictable level of quality in term of system ajr leakage and it is therefore accepted that designer may sometimes require tlle ystem to be tested in part or in total It should be ecogni ed that the testing of duct systems add a ignificant cost to the installation and incur some extra tjm within the programme (Se 47 and 64 re mandatory te-sting)
manufactured to a structural standard that is compatible with the system operating pressure There are three classes of duct con truction to eorre pond with the three pre ure clas meations Class A Lo pressure ducts suita le for a maximum positive operating pressure of 500 Pascal and a maximum negative pressure of -500 Pascals Class B IVledium pressure ductmiddot suitable for a rnaxilnuJJl positive operafjn o pressure of 1000 Pascals and a maxllnum negative pre sure of -750 Pa cal Class C High pre sure ducts suitable for a maximum po ilive operating pressur of 2000 Pa cals and a maximum negativ pres ur of -750 Paltcals
LEAKAGE FROM DUCTWORK Leakao-e front pia tic air ducts occur at the joint~ and is therefore proportional to the total surface area orthe du twork in th system Tb level of leakage i imilarly related to tIle air pres ure in th du t system and whilst there LS n precis formula for calculating the level of air los it i generally accepted that leakage will increase in proportjon to pressure to rbe pOvver of 065 The effect of air leakage from high pressure velocit ductwork is critical tn terms of system perfomlan dege energy consumption and the risk of high frequency noise as ociated with leakage These problems are le critical with medium pressure 10 ity systems but should be con idered Low pres mevelocity ducts present the lowe~t
ri k in tenn of tbe effect of leakage on the operation of the s stern
SYSTEM LEAKAGE LOSS As there i no di ct relatLonship between th volume of air conv yed and the surface area f the ductwork sy tern required to match the building configuratmn it is difficult to express air leakage a a percentage of total air volume Similarly the operating pressure will vary throughollt lh 3 system and a leakage is related to pre me the calculations ar comple However it is generally ac epted tbat in typical good quaJjty systems the leakage from
49
DW154 Specificatioll for Plastics Ductwork
each class of duct llnd r operating condition will be io the region of CIa S A low pressure 6 Clas B medium pres un 3 Clas C high pressure 2
A5 SPECIFYING AIR LEAKAGE TESTING Re peeting both the co -t and programme implications a sociated with te ling du 1 for leakage the designer may for example indicate that a particular system is te ted as follow
a) High pressure ducts - all tested b) Medium pr ssure duets - 10 of the
ductwork shall be s eet d at random and tested
c) Low pre sure - unte ed In any case where a random te t i elected for medium pre sure ductmiddot the followin c1au~e is suggested for inclusion by the de ign r
The designer hall elect at random a maxirnwlI of 10 of the dUCl system to bt tested for air leakage The duct hall be tested af the pressure recommended in Table J3 for the assifi atiol for the ectiol1 of the ductwork that is to be tested The tests shall be carried Ollt as the work proceeds and prior to the application of thermal insulation In the event of test failure of the randomlY selected section the designer shall have The right to select two La1her e tiolls at random for resting Where succes ive failures are identified there shall be a Tight to require rhl COl11raCWr 10 apply remedial attention to the complete ductwork system Th contractor shall provide documented eviden e of the calculalions used to arrive (1
the allowable 10 I for the section to be tested and the client or his agent shall willess and sign the results of the test
able 13 Air leakage rates
Maximum leakage of duct work Static
prcssUft Low-pressure edium-prc-sure I Iigh-prebull me diJfercntial Class A Class B Class C
1 2 J 4 Pa Litres per second per quare metre of surface area 100 054 018 ZOO 084 028 300 110 037 400 132 044 500 153 051 600 058 019 700 064 021 800 069 023 900 075 025
1000 080 027 1100 1200 1300 1400 1500
029 030 032 033 035
1600 1700 1800 1900 2000
036 038 039 040 042
Note Recommend d mean test presures are highlighted iD bold type with the actual selection being left to tll test operator
50
DW154 Sfeeiieaioll for Plastics Ductwork
A9
A10
and air leakage classification for the y em under test
DESIGNERS CALCULATIONS The designer can middotaJculate with reasonable accuracy the predicted total loss from a ystem by
a) Calculating the operatin presure in each ection of the sy tern
b) Calculating the surface area of the ductwork in each correspondin pre lire s ction
c) Calulating the allowabl~ los at the operating pressure for each ection of the system (see table 13 for allowable leakage figures)
VARIABLE PRESSUR S IN SYSTEMS De igner can achieve significant co t saving by matchina operating pressures throughout the system to constmctional standard and appropriate air leakage testing eO the practice of specifying construction tandards for whole duct sy tems based on fan discharge pre sure may incur unnece sary costs on a project For example ome large sy terns ould well be classiC ed for I akage limits as follows
Plant room risers CJas C Main floor distriblltJou CIa B Low pre sure outlets Cla A
A6 SPECIAL CASES There may be ~itLlations on a project where circumstance dictate thal pecial consideration be given to containing air loss s eg a long mn of duclwork may incur a di -proportjonate level of air 10 s In ca es such as thi example the designer can specify an improved tandard of airtighmess ie 80 of alJo~able 10 s for la B Ju ts The designer sbould not specif a CIa C t sI at CIa s C pressure for a CIa s B ducl
A7 SUGG S ED RANGE OF TES ING
A8 TESTING OF PLANT ITEMS Items of inline pJant (eg Fig 106 to 115) will not normaUy be included in an air I akage test The dllctwork contractor may indud such itelllS in tbe te t jf rh quipm ot has a certificate of COnfOlnlity for Ihe pres ure clas
bull High pressure duct bull Medium pre sure ducts bull Low pre sur ducts bull Exposed extract syst ID bull Ceiling void extract
systems bull Secondary ducts from
VAV or fan coil units bull Flexjble duct bull Final connections and
branches to grille and diffusers
100 test See A5 Untested UDt sted
Untested
Untested Untested
Untested
SI
i
DW154 SJecijicafion for Plastics Ductwork
ig 116 Permitted leakage at various pressures
Leakage in litres per second per square metre duct surface area
Vgt
o ltgt 0 ltgt N
ltgt Cgt
0 0 cc
0 0
~
g =
g ~
c 0
J
ltgt 0 I
~ ] tn
ltgt ltgt
In ol
~ 0 ~ 8 ~
~
c ltgt ltgt
~ CJ
~ ~ ~ ~ 8
0shyij
~ ~ ~ t
ltgt ltgt 00
l
~
~ Q
c C
~ rshy
e ltgt
I 1
I Cgt ltgtv
c Co ~
~~ ~ 10
I
0 Cgt
fJshyq 410 ) 1 ltgt
ltgt N
~ shy ltgt ltgt
~ I 1
c
52
DW154 Specificatio for Plastics Ductwork
Example of a completed test sheet Test No
General
Name of job N~ jC43Pt(r2lef Building Repound ~(~~0
Part 1 - Physical details
a Section of duct work to be tested ~(diffPIfff~el1f3rd Floor
b Drawing Number g91~~ c ssure aSSJ L atlOn V~Jl~IRfYgtg~~lPre Cl T Class C
d Test static pressure -(9 raErq~ ~~~~-~~J~~~ ~~ ~~~~ll
Leakaoe factor 9~-tre3$ecMz I OM REFTOTABLE 13)e b bullbullbullbullbullbullbull
f Surface area of duct under test Q~tJJItetre$ CPROMCALCU TIO BELOW)bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull ampampamp bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull
g ]Vlaxi mum permitted leakage -~ (~i~~0 ~~r~~ ~~~l-~-11~ ~~~Q
Part 2 - Test particulars
a Duct static pressure reading 9QFt~q~ ~ middot~~~1 ~~
b Manufacturer and type of liow measuring d vice (-~~~cJ~Y-9Q7EYg c Range of measurement of now measuring device QtP)OQ~(e~~~0I~~~~1~I~ ~~~~~~W~
d Reading of flm measurin o device pmiddot IFROM RIO)ftscag ~
I (DERlVED [ROM CHART SUPPUED WITH RIG US 0 ud)1e Interpreted air flow leakage rate ~(~~~f~~~ (~l~~~~~~~~~~~~~~~~~I
f Duration ~~~~~norn~allY l~ lnil1Ut~~d~~~ it1~ W~ Date of test ~(lITled ut by Wltll s ed by ~ ~
(~lJ MIJLrr) (Si~rrfltJUYJ
Printed Name 1~g0f~ Printed Name ~~Y~9~ and Company 7jl~~~~~( UJd CompanY AB COII$Itallt8
Width and depth or diameter
Periphery ength Area
millimetreS millimetres metre qL1are metre
800 x 750 3100 1755 5440
600 x 650 2500 557 1193
300 x 300 1200 120 144
305 din 958 700 670
250 dia 785 450 353
TOTAL 8000
53
DW154 Specijilarion for Plastics Ductwork
pA XB
Guida ce No es For he ransport Handling and
Storage of uctwork
avoid damage to adjacent duct panels In somc ca es particularly on con acts calling f r repetitive sizes the use of timber jigs and spacers may be justified Where reduced bulk and greater protection are major factor such as consignments for export transporting ductwork in L shape sections may justify the increa ed ite as embly co ts
It is recommended that before a contract is finalised that consideration is given to the subject of site acces material handling and storage as tbcy havgt a strong influence on the cost efficiency of the overall activity of ductwOlk installation
B3 Handling To minilnise th risk of damage duct sections should be clearly identified and deliveries to site should be closely linked to the installation programme so as to avoid accumulation of
B1 Storage and Handling of Ra Material Material should be stored in suitably designed racking out of direct unJight Where possible the e racks should be metal to earth Edges of cut she t may be harp and protective gloves are advised Wearing teel toe-capped boots is recommended Most pIa tic sheet is manufactured with smootb mfaces andor is suppLied with protective coating Care must be taken to prevent accidental lippag of stacked materials Beiuoshy good electrical insulators the movement of stock unless earthed will allow the build up of stati All stock shapes are chemically stable at normal temperature Whil t some raw materials used in their manufacture may themselves pre ent a toxic hazard once incorporated into the lOck bape they no long r constitute such a hazard and no dermatitic bazard are known nor are any
unfiJied ductwork and minimise double handling It is important to recognise that ductwork panels joint and corners arc susceptible to damage and care must be taken wheu band ling such material through a site During handling individual item of duct work may be liable to light cross sectional deformation until thev become an integral pan of a completed ductwork system Whilst this may temporarily detract from its intended appearance thi deformation will not have any detrimental effect on the functionality of the finally a semblecl system Installation of duct work and asociated plant items ill illevitably involve manual handUng The responsibi Iiry of employers and employees to a ses the risk of personal injury during mallual handling operations is et out in the HS E publication L23 Guidance on Manual Handling Regulations 1992
environmental problems expected 84 Site storage
B2 fransport Large capacity vehicles with high-sided open or closed-top bodies are tlle mo t suitable for the transport of dllctwork Careful consideration should be given to the
Adequate floor space IDust be provided within tbe building for the site storage of ductvork Such storage shalt make due allowance for thc stOf(ne of ductwork in stacks such that access ~ egt
between them is of sufficient width to pennil the removal of item without interference to
unloading of transport on sit a not all siJes b n fit from the material handlino- and access facilities that exi [ in a manufacturing workshop such as crane- fork-lifts or loading bay Site handJiog facilities along with
adjoining sta ks Ductvork components should be positioned so a to avoid crushing Ductwork of small panel size may be stored horizontally however care should be exercised to ensure that tack sizes are limited 10 within
ehicular acce s restrictions may itilluence the type and ize of transport to be uWised
engtlls of ductwork should be positioned 0
the tmctural strength of the duct sections to prevent distortion of the lower sections within the stack
as to avoid crushing Lengths Witll projections such as branches and bends i1anges girths damper quadrauL should be loaded so as to
54
DW154 S1tciic(ltioll for Plastics Ductwork
85 Internal cleanliness of new ductwork The site storage of ductwork introduces the important cODsideration of maintaining the internal cleanliness of the ductwork R feren e should be made to HVCA documentshybull DWffM2 Guide to Good Practice - internal
Cleanliness of New Ductwork Installations If the above conditioDs can not be satisfied consideration should be given by tJle designer to amending the specification to include for Po t Installation Cleaning as covered by tJ1C HVCA documentshybull TRJ17 Guide to Good Practic - Cleanliness
of Ventilation Systems
APPE DIXC
Fi e Retardant inishes C1 Improvement in the fire retardancy of plastic
ducts can be achieved to varying degrees and is wholly dependent llPOll the surface coating laminating resin selected and construction specification adopted In some instances smoke emission is coILSidered equaUy with other speci fication requirernen ts of the materials resistance to ignition and bumjng It is therefore important for design rs to establ ish the clients and officers detailed requirements and not rely on a tbird party interpretation of fire resisting or fire retardant Where possible the specification should refer dir etly to compliance with a British or European Standard identifying the specific sections applicable There are various types of resin and mat rcLnforcements that can achieve a Class 1 surface spread of flame ratin o when tested according to BS476 Part 7 (1987) This test puts materials illto Class I - 4 in descending order of perfoDllance according to the rat and extent of flame spread over their surfac under standard beating conditions Materials should also be tested for flre propagarion to BS476 Part 6 (1989) Tbi tesr measures the amount and rate of heat evolved by the material when subjected to standard heating
conditions Test results are given as an index of Perfonnance (i) whicb is based on three sub indices (iJ (i1) (h) The higher the value of the Index of Performance (i) the greater is the material s contribution to fire growth The higher the value of the sub-index 0) rhe greater the ease of ignition aod flame spread The highest product performance classification as defined in Approved Document B of the Building Regulations is Class O This is acLlieved if a material surface of a composite ploduct i~ either a) composed throughout of materials of
limited combustibility or b) a Class I material which has a tlre
propagation index (i) of not more than 12 and sub-index (i l ) of nor more than 6
01 J Class 0 is not a cla$sif1cation identified in any British Standard test
There are resin system reported to be classified to Class O when tested to BS476 Pcl1S 6 and 7 however designers need to ensure that such sysrems can be applied to their proposed design In propriety resinmat system available the fabrication techniques and COITect application are critical to the integrity of the reinforcing and clas ificatiol1 For example in some systems the u e of a non-fire retardant gelcont on a fire retardant substrate would reduce the classification For further information see HVCA publication DW144 Appendix D
55
DW154 SplCijiClIliol1 for Plastics Ductwork
x Guidance otes For nspectmiddoton Servicing a d
Clean-ng Access Openings
D1 GE ERAL This appendix highlight in ummary fOI111
the acce considerations that hould be made by the design r iD terms of inspection servicing and cleaning Having considered the seop and the design of the dUCI work system relative to the guidelines outlined below the designer should clearly indicate which levels of acces should be incorporated into the manufacture of a new duct work system (See Table 14 and Note I b low it
D2 DESIGN CONSIDERATIONS
D21 In ptction and servicing requireshyments are set out in Section 15 of Lhis specification
D22 Cleaning requirements are set out in the HVCA pubUcation TRl7 Guide to Good Practice Clean Lines of Ventilation Systems and the guide tates The precise location ize and
type of access would be dependent on the type of ductwork cleaning inspection and te ting metbods to b adopted Care protection and standards of cleanliness prior LO cOlllmisionin o
are set out in th AV A publication DWITM2 Guide to Good Practice Internal Cleanliness of New Ductwork Installations and th guide state Wh re specific limits of cleanliness are required ductwork sball be cleaned after installation by a spcialist cleaning contractor It will b in the interests of tht desioner botb financially and practically to cunsider employing a specialist c1eauing contractor at tbe
outset of a contract to internally clean newly installed ductwork prior to bandover This approach would reali e the following benefit shyi) Tb actual numb r of cleaning
access panels could be detennined to suit the method of cleaning to be adopted (This may be 1 s than the maximum requiremen listed under Lev 13 of Table 14)
ii) Clear directions could b given to the ductwork contractor as to tJle size and location of cleaning access panels that are required to be fitted during the mauushyfaclunng pro s
iii) The specialist cleaning operation prior to commi ioning vould enable the cleaning contractor to verify the practical acee requirement for the future cleaning operation associated -vitb a regular maintenance programme
iv) A specialist cleaning operation prior to commissioning would allow the designer to omit from the speeilicatiolJ the DWrrM2 requirem nt for factory sealing protection wipe downs and capping-off
v) Specialist Ieall ill 0 to the measurable standard defin d in TR17 will allow an objective definition of cleanline to be achieved
Car ful consideration must be gIven by the designer to the practl aJ problems associated witb the manufacture and fitting of suitably si Led access panel on small cross section duct and on the circular faces of rouod and flat oval ducts in particular
D23 Special con ideration must be given by the de igner to the practical problems associated with gaining personnel access to heavily congested ceiling areas and multi-la red du twork systems This approach would avoid
56
DW154 Spfciication for Plastics Ductwork
the possibility of access panels being D3 ACCESS 0 IN-LINE EQUIPMENT incorporated into a ductwork system at the This appendix unly covers acc il1spection manufacturing stage that were later found in through the ductwork body adjacent to an item practice to be inaccessible for either ervicing of in-line equipment and not openings in the or cleaning activities equipment itself
able 14 Acce requirements for inspection servicing and cleaning
HVCA PUBLICATIO REFE NeE (uidtgt 10 Gund Prartict
Adjace t OW144 Cleanliness orVcnlillltio S~lcr~ fRjJ7
in-line LeyeJ 1 Level 2 Level 3 ite sequipment pcdionSen lcin~ Section d C1eaniJl( SUn(O)lnspc lion Palle ltk~m_n
2011 (minimum OiL Jubje-ct to duct ~zel (ft~ -Panels
Control Da pcrs One (inspection) 203 One 300 mm x 200 mm Both sid Fire Dampers One (sCTjdJl~) 20211 One 300 0101 x 200 mm One side HeatingCooling Coils One (inspedion) 20213 One 300 mm x 200 mm (lIpstream) Both sides Attenuators (rectangular) None required One 300 mm x 200 mm (downstream) Both sides Attenuators (circular) one retluired One 300 mm x 200 mm (downstream) One side Filter Sections One (inspection) 20212 one required Uoth sides Air Turn Vanes None requjred None required Both sides Changes of Direction None required one required One side In-Duct FansDevices One (inspection) 20213 None required Both sides l
1 In the absence of any indication by the designer only Level ) access will be jncorporated into a new ductwork system
2 Tbe panel izes associated with Lev lis I and 3 acee s ar e middottablished by reference to Section 20 of DW144 and Section 2 ofTRll7 respectively
57
DW154 Speclfifatio for Plastics Ductwork
pA XE
B-bliography Included in this Bibliography are technical pUblications which may be of interest (0 ductwork designers fabricators and erectors and to tho e in the heating ventilatlng air conditioning industries generally nquiric should be made of the relevant organisation at the address quoted Since its publication other addresse contained within 0V154 mav have changed and some pubJicalions may have been superseded
HEATING AND VENTILATING CONTRACTORS ASSOCIATION
4 Palace Court London W2 4JG Telephone 020-7229 2488 Fax 020-7727 9268
Orders fo FlY A Publications Old Matlsion House Eamont Bridge Penrith Cumbria CA 10 2BX (Telephone 01768 864771 Fax 01768 86718) Email hvcapoblicationshvwelfarecouk DWn 44 pe ilicatiun for sheet mctal duclwork (Iow- mediulllshy
and high-pressure) 1998) DWIl4 A practical guide to dUGI ork I akage te ting
(revised 2000) DWII54 Specification for plastic~ duct rk DW171 Guide to good Practice for kitchen venlibtion system DW191 Guide to good pracuce glass fibre ductwoJk DwrrMI Acceptance cheme for new products - Redangolar cro
joint classification Guide to good pra tice - Internal cleanliness of new ductwork installations Guide to good practice for the design for the Installation of lire and smoke uampers
J 1Other puhlications
HampV safely guide 5th edition JS2 Tool box talks JS5 Weldlng Safety booklet JSI9 afety facts bo klet Fact sheets 1-24 2nd edition JS2J COSHH manual volume 1 Advice on compliance with the
regulations 1521A CO I-rH manual volume 2 Asses mcnt h ets JS23 Ri k management manual TR3 BrazinltT and bronze welding of copper pipework cUld sheet
(I 976) TR5 Welding of carbon steel pipework (1980)
TR6 Guide to Good Practice for Site Pre sure Testing of Pipework (19 0) Guide to good practice cleanliness of ventilation Ylem
CHARTERED IN TITUTlO OF BUILDING SERVICES E G EERS Delta House 222 Balham High Road London SW12 9BS rTelephone 020-8675 5211 Fax 020-8675 5449) CIBSE Guide Volume A Design Data Volume B In tallatiol1 and quipment Data Volume C Reference Data
CommlssioniJIg Codes These Codes eover the preliminary checkS eUing to work and regulation of vanous catcgories 0 plan The Codes give a guide to design implications Series A Air Distnbution Systems Series B Boiler Plant
ri s C Automatic Conlrol ystems Cr1es R Refrigerating Sy terns
Sene iN Water Distribution Systems
Technkal Memonllda TM 4 Design Notes for the Middle East TM bull Design otes for Ductwork TM 13 Minimi iog lhc Risk of egiounaires Disease
Research Reports RROI95 Ventilation system hygiene - A review of published
infomlatioo on lhe occurrence and ffects of Olltamination Rl~02J95 Air-to-air heal rec v ry RR0395 rnfluen e of HV C on smoke detectors
ATlONAL ENI [ERING SPECIFICATION LfMITED Southgatc hamber 3739 Southgate Street Winchester S023 9EH (Telephone 01962 842058 Fax 01962 R(8982) BUfLDING S RVICES RESEARCH AND [ ORMATION ASSOCIATIO Old Bracknell Lane West Bracknell Berkshire RG 12 4AH (Telephone Brackl1eU (01344) 426511 Fax 01344 487 -7 )
Application Guides AGln4 De tglJing Vana~le Volume middotylans for KOOnl
iir Movement AG1I91 Commissioning of V Sylcms in Buildings 11 6194 Fire Dampers
B) 94 cntiJalion or KitcneTls
AG389 The Commls ionin of Air Systems In Buildmgs AH2192 Commissioning of Bern - A ~ode of Practice TN2417 I Fire Dampec il) Ventilating Ducl
BEATING VENTILATING A AIR CONDITION G MA UFACTURERS ASSOCIATIO (HEVAC) HEVAC Henley Road Medmenham Marlow Buck SU 2ER (Telephone 01491 578674 ox 01491 575024 Emoimiddot infofetacouk)
Publicatjons Air Diffusion Guide Guide to Air Handling Unit Leakage Testing Guide to Good Practice Air Handling Unit Real Room Acoustic ~ st Procedure Specification for the ertiiicatioll ofAir Filters Method of Test for Water Rejection PerfOnTlatce of Louvrcs Subjected 1(1
Simulated Rainfall Test Procedure for Acoustic Loo cs Specification 10 Floor GrilJes - Types Performan e and Method ofTest Specification for the Determination of the Collection Efficiency of SilJ1d
Trap Louvre Domestic Mechwlical Vclltllalion Systems with Heal Recovery Fan Application Guid
~an and Ouctwork Installation Guide Guide to Fan Noise and Vibration
pecification of Requirements for JallJral Smoke and Heal Exhausl Ventilators
pecification for Powered Smoke and Heat Exhaust Ventilators
Specification of Requirements for Smoke Curtains Design Gujue of Smoke Ventilation for Single Storey Lodustrilll Building~
Including those with Mezzanine Floor and IIi Racked Storage Warehou es - Issue 3
Guidance for the Design of Smoke entilation YSlem for Covered and Undergrollnd Car Parks - lssue 1
Application of SOloke Control Equipment and Syst m Guid to Good Practice - Isue J
58
DW154 Sp(C~tiifitiol for Plastics Ductwork
BRITISH STANDARDS INSTIT TION Sales Department 101 P ntooviLle Road London NI 9ND (felephone 020-78 1 78801)
CP 413 1973 Ducts for building ervices
SS 476 Fire tes on building matenals and lruc(ure
Part 4 19 4 Non-combustibility lest or materials
Part 6 I Fire propagation lest for materials
Part 7 1993 Surface spread of tlarnJ tesls for materia
Part 20 1987 Fir resistance of elements of construction
Part 21 1987 Fire r sistlUlce of loadbeanng elements of construction
Part 22 1987 Fhe istallceofllon-loadbearing elemcllts ofconsttuclion Part 23 1987 Contribution of componcnts to the fire resistance 0 a
structure
Part 24t987 Fire resi lance of wl1lilation ductl
SS 5588 nan 919 0 Fire Precautions III thc desIgn and OOSlnJ lion of buildings
S 729 1971 Hot dip galvanized oatiugs (or irOIl aod stcel articles
BS 1449 Steel plate sheet and Irip
Pan 11991 Carbon steel plate heel and strip Part 2 1983 Stainless steel plate sheer and strip
and
B middotENJOI49-2 996 BSEN 10149- 1991)
BSEN 10131 1992
BSEN22063 Sprayed metal coarings 1994 Protection of iron and steel by aluminium and zinc against
atmospheric cOlosion Irotectiotl of iron and ste I against corro ion and oxishydation at elevared temperatures
BS 353 1981 Glossary of lerms relnting to thermal insulation
BS ISO 1479 Self-tapplngscrewsandmetallicdri c crew
B -lSO 7049
1994
B 4800 1989 Painl colour for building purposes B 4848 l0 rolled structural steel sections
Part4 1972 Equal and unequal angles BS 5422 1990 Specification for the use of therm illuating matcriulS
SS 5720 1979 ode of practice for mechanical veutilating and air C 11shy
dirionin bull in building
l3S PR 12814-1 Bend resting for plasric welds
SS PR 12814-2 Tensile testing for plastic welds
SS PR 13067 Appro altesting for plastic welds
BS PR EN I 100-] Vi ual in pection ofplaslic welds
SHEET METAL AND AIR CONDITIONING CONTR-CTORS NATIONAL ASSOCIATION INC (SMACNA) Headquarters 420 I Lafayeue Center Drive Chanlilly Virginia 2051-1209
Mailing Address pa Box 221230 Cbantilly Virginilt120 153-1230
Telephone (703) 803-2980 Fax (703) 803-3732
Accepted IJJdustry Pl3Gtice for Industrial Duct Constnlelion 197 ) i-rchitecmral Sheet kwl Manual ([993)
Comractors Guide lor Modification 10 ooslruerion Colllraets 1993 Ducted Eleclric Heat Guide for ir Handling Ssrerns (1994)
En~rgy ollservatioD Guidelines (1984) Energy Recovery Equipment yslClllS (199l
Fibrou GIns Duct onS1ntClion Standards (1992)
Fire Smoke amp Radiation Damper In tall Guide for HVA Syst ms (1992) Guide t leel Stack 1(95)
HVA Air Duct Leakage Test Manual (19 ) HVA COlllmissioning lvlanual (1994)
H A Duct Construction Standards-Metal amp Flexible (1995) Addendum 01 (Nov 1997)
HVA Duct Systems Inspection Guide (1989)
HVA ySlems-Application (1986) nVAC ByternS-DLlct D ign (1990)
HVi Systems-Testing Adjusting amp Balancing (1993)
indoor Air Quality Manual (1993) tcheu quipment Fabrication Guidelmes (1990)
Managers Guide for elding (1993)
Rectangular Industrial Duct Cons1TUction Standards (19 0) Round Industrial Duct oustmction Standards (1977)
Sei mic Restraint Manual (1991) (wl Appendix E 1993) SMACNA Ma le Index ()fTechnical Publications (1995) Tbennoplnstic Duct CPY ) Construction Manual 1994)
DEPARTME OF THE ENVIRO MENT (Publications Centre) H Stationery Oflice 5 Nine Elms Lane London SWS 5DR
MampEJ 011972 Electrical in tallat1011 in buildings ( ew Editiou)
IampE 0319 Healing hot and cold wat r steam and gas losla1lations for buildings
M amp - No4 1970 Central heating and hot and cold ~ ateT in tallations for
dwelling
M amp ENo100 1971 Mechanical ventilation for building~
ASSOCIATION FOR SPECIALIST FIRE PROTECTlO As ociation House 235 Ash Road AJdershot Hampshire GUl2 4DD
Telephone OJ25221322 Fax 0 J252 333901
lublicalioos Fire Ratcd and moke Outlet Ducrwork An Industry Guide t Design and InSlalla lioll
HEALTH AND SAFETY EXEC TIVE Rose Court 2 Southwark Bridge London SEl 9HS Telephone 020-7717 6000
TWJ THE WELD G TlTUTE Abington Hall Abington Cambridge CB16AL Telepbone 0 J223 89162
Publication DatJ Oil w~ldll1g of lhermopla lics
59
DW154 wciiwlioll for Plastics Ductwork
A -=--DIX
Factors
Specific gravity shy pp = 091 approx UPVC = 14 approx
Some miscellaneous conversion factors
To convert
Length Inches to millimetres Feet to metres
Multiply by
2540 03048
To convert
Millimetres to inches Metres to feet
vIultiply by
003937 3281
Area Square inches to square millimetres 6452 Square millimetres to square inches 000155 Square feet to square metres 00929 Square metres to square feet 10764
Volume Cubic feet to cubic metres Cubic feet to litres Gallons (UK) to litres
002832 2831 4546
Cubic metres to cubic feet Litres to cubic feet Litres to gallons (UK)
35315 00353
022
Mass Ounces to grams Pounds to kiJograms Tons to tonnes
2835 04536
1016
Grams to ounces Kilograms to pounds Tonnes to tons
003527 2205
09842
Volume flow Cubic feet per minute to cubic Cubic metres per second to cubic
metres per second 0000472 feet per minute 2119 Cubic feet per mIDute to litres Litres per second to cubic feet
per second 04719 per minute 2119
Motion Feet per minute to metres per second 000508 Metres per second to feet per minute 197
Pressure Inches water gauge to millibars 2491 Inches wateJ- gauge to pascals (Pa) 2491 I Pa = I ewton per square metre = 10-2 millibars
60
Heating and Ventilating Contractors Association Esca House 34 Palace Court London W2 4JG
Tel 020 7313 4900
e-mail contact Itvcaorguk web site wwwhvcaorguk
Fax 020 7727 9268
DW154 Spaijicllliflll for Plastics Ductwork
PAR 2 54
Standards
5 APPLICATION
51 This specification sets out minimum requirem nts for tbe manufaclure and in-tallation of ductwork for commercial and industrial fume extraction and exhaust 5y terns made from any of th material listed in Seclion 7 and being within the limit of ize andor material Ihickness speci led in Ihe relevant tables Normal ambient operating temperatures are assumed within the pressurevelocil limits and the limits of air leakage for the various pressur classes prescribed in Table 1
52 Thi specill alion is inlended to apply to ductwork handling fume-laden air which are polluted or is otherwise exceptional in respect of temperarure or humidity (including aturated air) for dllctwork wber the external
surface are exposed to a hostile environment The design construction installati n supports and finishes in such case should be giv n special consideration b the de igner in relation to tbe parti [lIar requir ments of each application
6
61
53 TIlis specification is sllitabl for ductwork expo ed to external atffio phere The designer will need to ~ive sp cift details of any special finish constlUction (See eetiar J9)
62
This specification i ba ed on duct operating environments of not less than - 100e and for
PVC (non GRP reinforced) nor exceeding 40degC UPVC reinforced wilh GRP not exceedin cr
600 e PPS and PP not exceeding 60deg FBPP reinforced witb GRP not exceeding 70degC Systems required to operate at temperatur outside those d tailed above aJthough outside of Ih scop of Ll)is specification are Dot precluded but the ductwork hould be designed from fi rst principle Ilaving regard for the physical mechanical and chemical properties of the material It mu~t be noted that the cOlTosive re i tance of all the above m terials will decrea e at temperatures approaching 5deg to looe below the parent materiaL beat distonion point Further guidance on temperatup effect is provided in Fig 34 Linear Tbennal
xpansion and Fig 35 Typical 0 ign Stres es for VC and PP
DUCTWORK CLASSIFICATION AND A R LEAKAGE
Classification and air leakage limits Duc work la sification and air leakage limitmiddot are eL out in Table 1
Compatibility with CEN The leakage fa tor u ed in able 1 for Classes A Band C ~u-e the ame as those for the cIa e similarly de ignated in th E Document Pr E 12237Pr L507
Table bullbull uctwork Class icati nand ir Leakage Limits (Reproduced from DWI144j
Ducl pressure class
1
Low-pressure -Medium-pressure -High-pressure
-I
I Class A Class B
Class C
Static pr sure limil Air I akage LimitMaximum air
litres per ltccnno per quarevelocity
Positive Negalive metre of duct surface areu
2 4 5 ~ -Pa Pa
f-m1s
0027 X pors500 10500 --1000 0009 x po6~750 20
0003 x pO652000 750 40
Where p is he differential pressure in pascals
Nole Tllls specification DWl54 onJy covers construction up to 1500 Pa
8
- - shy -~----
- shy
DW154 SpeciiCfllioll for Plastics Ductwork
63 Leakage at various pressures and other 110 mm to 600 mm dia (Dimensional rela tionships tolerances to DIN 8062) Applying the limits specified In Table 1 Appendix A (Table 13) sets out the permitted 74 PPS (Forms aailable) leakage at each of a serie of pressures up tu a maximum for each class Incloded in that 741 Extmded sheet in thickness 3 mm to Appendix is a graphical presentation of the 12 mm (Dimensional tolerance to pre urelleakage relationship DIN 53479)
DWl143 A Practical Guide to Ductwork 742 V series tube in sizes 1] 0 mrn lO 630 Leakage Testing provides detai Is of the basis mm dia and fittings in size I 10 mm for the leakage limits specified in Table 1 to 400 mm dia (Dimenional
tolerances DIN 53479) 64 Air leakage testing
Air Jeakage testing of low and medium 743 All PPS material used hall be pressure ductwork is not mandatory under compatible and comply with DIN tJlis specification Air kakage testing of high 4102 part B and SS 476 part 7 class pressure ductvork t mandatory under this 4 PPS material should not be used for specification and for details of testing external applications vithout suitable procedure refer LO DW143 A Practical Guide protection (See Part 6 section 19) to Ductwork Leakage Testing
744 It should be noted thal PP is not fully 7 MATERIALS compatible wilh PPS
71 Application 75 FBPP (Forms aailable) This specification applies to ductwork constructed from materials as defined below 7 51 Sheet in thickness 3 mm to 9 mm or equal Minimum material thickness is to be taken a a nominal thickness as Tables 267 7 52 Continuous roll form in thickness 2 10 amp 11 AJJ UPVC materials ued shall be mm to 4 mm low flammability selfextinguishing compatible and UV stable with pigment colour to RAL 7 53 This particular material is specifically 7011 and DIN 4802 B 1 designed to be externally reinforced
with GRP (See Section 24) 72 Types
The materials covered by thi specification are 76 UPVCGRP abbreviated herein as foIlowsshy This is a form of composite lamjnate used (UPVC) Unplasticised polyvinyl chloride where improved mechanical trengtb UV (PPS) Self eXlioguihing polypropylene stabilisatiolJ or fire retardence is required (PP) Polypropylene (GRP) Gla s reinforced plastic 77 UPVCIFOAMJGRP (FOAM) Rigid polyurethane self FBPPFOAMfGRP
extinguiShing foam This is a form of composite laminate used (FBPP) Fabric backed polypropylene sheet where insulation andor support is required for
special applications 73 UPVC (Forms available)
8 DUCTWORK CONSTRUCTION 731 Extruded sheet in thickness 3 mm to AND JOINT SEALING
12 mm (Dimensional tolerances to DIN 7748) 81 Ductwork construction
The election of longitudillal cross joint and 732 V series tube in sizes 110 mm to stiffener types within the criteria laid dOT1 in
1AOO mm dia and fittings in siz~ Part 3 amp 4 shall be used as a minimum standard
9
DW154 Spet((icatioll for Plastics Ductwork
82 Joint sealing and sealants 8226 The joint mu t be held in po ition ror at leamiddott 5
821 General minutes A jig should be The integrity of the ductwork used jf nece-ltsary to ensure depends on the successful applicatioll that no twisting force i of tbe conemiddot t jointing metbod appl ied to th joint during
the period 822 Solvent cementing
Solvent cementing a atisfactory 8227 Once made the joint method of jointing circular UPVC should not be exposed to socket anu spigot or leeve joints a undue force for eight certain solvent based cement horn shy hour Tb full strength of geneously bond the PVC surface the jOjJlt is not achieved in providing uitabl joints Solvent less than twenty-four cementing i not practicable with PP hours because of its hioh resi tanc to solvents The procedure recommended OTE SOLVENT CEMENT JOINTING by the cement manufacnJrer should METHODS ARE TOT RECOMshybe followed but the following points ME DED FOR RECTANGULAR are important DUCT SECTIONS
[N ALL CASES S ALA MATshy8221 Clearance between ocket ERlALS MUST BE APPLIED
and spigot must be STRICTLY IN ACCORDA CE minimal because of the WITH THE MANUFACTUR ~RS
lirnited gap filling propshy 11 STRUCTIO SAD OSHH ertie of the cement ASSESSMENT
8222 Inside edges of sockets and 823 Hot air welding utside edge of spigot VC and pp a be welded by
shouJd be lightly chamshy Llsing the hot ga Ifil1er rod meUlOd fered ltmd thoroughly cleaned described helow
8223 Mating urfaces should be 8231 The welding gas can be cleaned using a proprietary nitrooen or compressed air solvent cleaner to remove and shltlll b fIltered free grease and slightly etch the from suspended water oil surface vapour and particulate
matter 8224 The cement should be
applied a quickly a 8232 The filler rods shall be possible to the socket and made from material to r pigot over the full area of compatible with the matshythe mating surface are eriaJ being welded should be taken to avoid the use of excessive 8233 Butt weld joints shall be cement bevelled to an included
angle of 60deg to 90deg and 8225 The posi liolling of the joint where po sibl welds shall
mUSl be achieved immedshy be fully penetrated from iately after the cement i both ide of the work applied aJld surplus cement removed
10
DW154 Specificatiol for Plastics Ductwork
8234 The joint face and the filler rod surfaces must be clean and grease fre and preferably roughened b shyfore welding In particular any deposited filler rod that is charred mu t be scraped away before additional runs are added
8235 The numbers of runs of fi lIer rod shall be sufficient to give a thiekne s of era s section of the veld at least equal to the thiekn s of the sheet
8236 Where high frequency park testing i specified lhi shall be undertaken in accordance with tbe weldshying in tmction handbook
Note A full descriplion of welding method is given in the Welding Institut handboo entitled Data on Welding of Thennoplastic Relevant BS amp CE Standards are prEN 12814-1 amp 2 prE 13067 and prE 13100-1
824 Completion of compo ite laminate joints Following solvent ementing or hot air welding of joints campi tion of any specified external laminate shall
carried out to maintain thebe
825
integrity of the construction (S 8227)
Gaskets These can be fabricated from various materials in the form of a pre-formed roll she t or trip applied between opposing faces of fbnced ross joints It i a visable to select material r commended by th ga ket manufacturer for the pecific appucation intended
PART 3
Rectangula ucts
9 RECTANGULAR DUCT SIZES
91 This specification covers duct size up to a rnLltimum longer ide of I -00 mm Duct size with an a peet ralio greater than 4 I ar not recommended Although they offer no problems of construction they increase friclionaJ resi tance and the pos ibility of Dois
10 CONSTRUCTION
101 General Th minimum constructional requiJement r r UPVC and PPPPS un-reinforced are hown in able 2
102 Longitudinal seams Longitudinal seams should Dot be located at corners or in the underside of the duct
103 Sheet jointing seams Seams shall be joined by continuous filler rod hot air welding or by fl1sion Vi ldiug only other form of jointing are not acceptable
104 Socket and spigot joints Sock t and spigot joints shall be formed by purpoe made double cket pi ces 100 mm long and of the ame thiekne material as the duct welded into position on each standard length of duet forming 50 mm de p sockets prepared and ready for final jointing on site with filler [Od of the ame formulation used for prefabrication (See Table 2)
105 Flanged joints
1051 FJa ges Fabricated flanges shall b con tmeted u ing miniumum of 9 mm thick by 50 nun wide material of matching formulation depending on duel size as hown in Table 2 The flange hall be mounted true and square to the duct surface and w lded on both sides a 103 and Figs 3 4 Alternative con truction Illay be
11
DW154 Spedjicfltiotl for Plastics Ductwork
utilised for attacllment to plant or other equipment
1052 Drillings Drjllings shall be placed to permit clearance to tbe extel11al casing and any reinforcement of tbe ductwork for the application of fastening
1053 Fastenings For nonnaJ application bright zinc plated bolts nuts and vashers hall be Llsed in sizes and pitch centres shown in Tabl 3 Where special conditions prevail consideration of other material finishes such as stainless steel bolpounds nuts and washers may be used In all cases gasket materials as Section 825 shaLL be used
106 Expansion joints Wher the configuration of the ductwork does not provide for movement due to temperature change or where such movement is restricted by branches or attachmenL expansion joints should be specified by the designer (See Section 18 FlexibleExpansion joint connections)
It is the re ponsibilir-y of the designer to identify the positions of any necessary expansion joints hased upon design param ters for the individual systems (See Figs 23 to 25 34 amp 35)
Design ote xamples of expansion joints shown in Figs 23 to 25 are not suitable for movement exceeding 30 mm
107 StilJeners
1071 External stiffeners Shall be fitted as specified in Tables 2 amp 10 and Figs 5 amp 6
1072 I temal stiffeners The u e of internal stiffening or bracing shall be acceptable iJ deemed necesary and approved by the designer (See Fig 7)
11 FITTINGS
111 Standardisation of fiuings The terminology and descriptions of rectangular duct fittings a et out in Section 25 are recommended for adoption as standard practice to provide common terms of reference for desi crners quantity surveyor and ductwork contractors and for those using computer in ductwork design and fabrication
Bend are designated as hard or easy and the e terms as used herein have the folJowin o
meanings
Hard signifies rotation in the plane of tb longer side of the cross ection
Easy signiiies rotation in the plane of the shorter side of the cros section
An example iIlu trating these term ] given in Fig 8
Fitting are fabricated by cutting and welding sheet
112 Stiffeners Shall be as 107 and Tables 2 amp 10
113 Splitters Shall be as shown in Fig 41 and welded as 1003
114 ruing vanes Where square bends are required turning vanes as shown in Fig 9 hall be fitted
115 Branches When fitting branch ducts to a main duct care should be taken to ensure that the rigidity- of the duct panel is maintained in terms of tbe sti ffenillg criteria
116 Change shapes Where a change bape is necessary to acconUllOdate the duct and the cross- ectional area is to be maintained the slope haU not exceed 225deg 011 any side (See Figs 52 to 56) Where a change in shape includes a local reduction in duct cras - ectionaJ area the slope should not exceed ISO on any side and tbe reduction in area should not exceed 20 Where tceper angles are necessary due to ile
12
DW154 Spec([icatirJ1l for Plastics Ductwork
restucllOn splitters shall be provided Taper Transformation pieces from circular 10 square pieces reducers and transformation piec s or rectangular shall be made as long a shall be manufactured from the tbickl1 s of p sible and uJe angl ball be uot mor than material specified for the larger size ducl 225 (Fig 55)
loon Pa 1500 Pa
2 3 4 5 6 mm mm mm mm
3 socket amp spigot - - -or tlanged
as Figs 1 2 3 401 to 600 45 flanged 50 x 9 flat 1200 800
50 x 9 flat welded both sides a Fig 3 as Fig 5
601 to 1000 45 flnged 50 x 9 flat 800 600 50 x 9 flat welded both sides as Fig 3 as Fig 5
1001 to 1500 6 anged 75 x 9 flat 600 600 75 x 9 flat welded botb sides as Fig 3 as FieJ 5
or or 70 x 70 x 9 angle 50 x 50 x 5 angle
as Fig 4 welded both sides as Fig 6
N t For constructional operating temp rature limits refer to Part 2 Clause 54
Longer Pitch Bolt Size
Side max 2
mm 1m mm Up to 400 100 8 with washers 401-600 tOO 10 with washers
601middot1000 100 10 with wash rs 1001-1500 100 10 with oycrsized
washer
13
Table 2 inimum con tructional requi ments - rectangUlar nmiddotreinforce UPVC and pp
Joints Sliffeners Maximum spacinOLonger Side MillirnUlll She t between
Thickness Joint~S(iffi ners
mm Up to 400
DW154 SpedflCiltion for Plastics Ductwork
Cross joint - recta gular ducts
Fig 1 Socket and spigot joint (UPVC and PP)
Conlinuou weld joint on sile onlinuou- wcld
CT~r~T2
Fig 3 Flange joint (UPVC and PP)
ontinuou weld
Fig 2 Socket and spigot joint (UPVC only)
Fig 4 Flange joint (UPVC and PP)
S iffeners - rectangular ducts
Fig 5 Flat Fig6 Angle
Oatim wo]
Fig8 Bends - examples of hardTie rod assembly and easy
Hard
Fig7 With spacers Easy
4
DW154 Speci(uariml for Plastics Ductwork
Fig 9 Turning Vanes
HOWl G TYl AL EXAMPLE OF FOCI G
15
Ma vane length shy 615 mm
Example ofbraemg when V1IIle length exeeed max pennined Ahematively two banks of ncs fixmg the centre rail together at ] 50 mm nrrcs
U~_II---- fixed to dnct wall both CDds
bLEVATION
vane
Maximum distance between centrc oflUming vanes should [Jot exceed 60 mm pitch
DW154 SPCCijicllfiull for Plastics Ductwork
practice to provide common terms ofPA T4 reference for designers quantiry urveyor and
Circular Ducts
12 CIRCULAR DUCT SIZES Th duct sizes [n Table 4 have been selected from the ISO and C standard ranges as the 132 preferreod sizes
Table 4 Circular ducts shystandard extruded tube sizes
133 Extruded tube
ISO Standard Sizes (Nominal Diameter) 11
Wan Wall Thickness Thickness
mm mm mm mm 110 500 4022
I25160 600 50 I25200 630 60
225 25 700 60 13425250 800 63
280 900 70 315
23 23 80
355 1000
25 1250 104 400 32 1400 108 450 35
Note The above sizes are subject to normal manufactl1ring tolerances Other size may be available in varying wall Lhicknesses and subject to test and operational pressure
13 CONSTRue ION
13 General Tllis specification covers duct sizes up to a maximum diameter of 1500 mm The minimum constructional requirements for UPVC amp PPPPS un-reinforced ducts sball be as Tables 6 amp 7
ductwork contractors and tho e using computers in ductwork design and fabrication The requirements for circular duct fittings apply throughout the size ranges covered in this specification
Sheet jointing seams Seams shall be joined either by continuous fLiJer rod hot air welding or by fu ion welding Other forms of jointing are not acceptable
Socket and Sl)igot joints Socket and spigot joints shall be formed by purpose made double socket pieces 100 mm long and of the same thickness material as tJJe duct welded into position on each tandard length of duct forming 50 mm deep sockets prepared and ready for final jointing on ite with PVC adhesive andor fill r rod of the same formulation used for fabrication
Flanged joints
1341 Flanges abricated flanges shall be conshy
structed using minimum of 9 mm thick by 50 mm wide material of matching formulation depending on duct size as shown in Tables 6 amp 7 The flange shall be mounted true and square to the duct surfaces and welded OD both sides a 103 and Fig 12
1342 Drilliogs Drilling ball be placed to permit clearance to the external casing and any reinforcement of the ductwork
1343 Fastenings For normal application bright zinc plated bolts nuts and washers hall
16
For srualler diameters preformed fittings are available otberwise fitting are fabricated from segments of duct or sheet welded together
The terminology and description of circular duct tiltings as set Ollt in Section 25 are recommended for adoption as standard
be used in sizes and pitCh centres shown in Table S Wh re special conditions prevail consideration of other material finishes such as stain le steel bolt nuts and wasbers shall be u ed In all ca cs gasket materials as Seciion 825 shall be USed
DW154 Speciliwriml for Plastics Ductwork
135 Stiffeners
1351 External stiffeners Shall be fitted as specified in Tables 67amp 1 I and Fig 13
1352 Internal stiffeners The use of internal stiffening or bracing hall be acceptable if deemed neces ary and appn ved by the designer
f 36 Expansion joints Where the corrfiguration of the ductwork does not provide for movement due to temperature
Cross joints - circular ducts
change or where such movement is restricted by branches or attachments expansion joints should be fitted (See Section 18 Flexible Expansion joint connections)
It is the responsibiLity of the designer to identify the position of any necessary expansion joints based upon design parameters for the individual systems (See Figs 23 24 2534 amp 35)
Design Note Examples of expansion joints shown are not suitable for movement exceeding 30 mm
Fig 10 Socket and spigot joint (UPVC and PP)
ConLinuous weld joim on ite Ontinuous weld
crlr~l
Fig 12 Flange joint (UPVC and PP)
Continllous wcld
boil
Continuous weld or Solvelll cement
Solvelll ccmcnl joim on sile
Fig 11 Socket and spigot joint (UPVC only)
Stiffeners - circular ducts Table 5 Fastening centres shycircular duct flange jointsFig13 Flat
flat conljnlJou~ly welded Diameter Pitch Bolt Size
max
1 2 J 11
1 shy -~
mm mm mm Up to 600 100 8 with washers
601middot1000 100 10 with washers - ---I
1001middot1500 100 10 with oversized washers
1
Minimum offourfixings
17
DW154 Specifiiutiofl for Plastics Ductwork
Table 6 constructional quiremen s - circular unshy inforced U VC
Diameter Minimum Joints Stiffeners Maximum spa ~in r
Sheet between Thickness Jointsl tiffcners
1000 Pa 1500 Pa
1 2 3 4 5 6 UD mm mm mm mm
UO to 600 3 socket amp spigot as Figs 10 11
or fla ged Fig 12
601 to 1000 45 socket amp spigot 50 x 9 flat 2400 2400 as Figs 10 11 welded bo sides
or Oanged as Fig 13 as Fig 12
1001 to 1500 6 Hanged 75 x 9 flat 1200 1200 as Fig 2 welded both ides
as Fig 13
Applies 10 Tables 6 alld 7
Note 1 For constructional operating temperature limit refer to Part 2 luu 54 2 To allow for conicleration or extruded se lions or fabricated component the materia] tllicknes i hawn a nominal
Table 7 Minimu onstrucfional requirements shy circular un-reinforced PPS and
Diameter Minimum Joints Stiffcners Maximum pacio Sheet between
Thickness Join sStiffener 1000 Pa 150n Pa
I 2 3 4 6 mm m m mm
110 to 500 3 socket amp spigot as Fig 10 or flaoged as Fig 12
501 to 750 45 ocket amp spi~ot
as Fi 10 or Uanged as Fig 12
751 to 1000 6 tlanged 50 x 9 Oat UOO 12 0 as Fig 12 welded nth sides
as Fig 13 1 1 to 1250 6 flanged 75 x 9 flat 800shy 800
as Fig 12 welded both sides as Fig 13
1251to~ flangcd 75 x 9 Oat 600 600 as Fig 12 welded both sides
as Fig 13
18
DW154 Sped(icalirm for Plastics Ductwork
PARTS
Hangers an Suppo ts
14 GENERA
141 Supports are an e sentiaJ part of me ductwork system and their supply and in tallation are normally the responsibility of the ductwork contractor The principl s are a I-rvCA publication DWIl44 Part 6 Section 19 and should be read in conjunction with this document
Design Note Designers may pecify specific requirements wbich will supersede guidance given in DW144
142 Rectangular ducts abl 8 give the- minimum requirements for
hanger and supports for un-reinforced ductwork
143 Circular ducts Table 9 gives the minimum requirements for hangers and upports for uD-reinforced ductwork
144 Vertical d cts The design of supports for vertical duct is dictated by site condition and where practical duc hould be upported at 4000 mm interval or where tbey pa s through a floor (but n ver exceeding 4500 mm) see Figs 17 amp J8
145 External ducts Where ducts are external to buildings and may be ubject to wind loading support should be plac d so as to restrain ide tl1ruSt and should allow axial movement as neces ary It is the respon ibility of me de igner to calculate the effect of the particular prevailing condition and to define any special upport requirement
146 Expansion joints Support shall be designed to permit axial movement only and shall e provided on eitl1er ide of expansion joint
I 1shy
I~
mm -Jp to 400
401 to 600 601 to 1000
Table B Hangers and Supports - rectangular horizontal ducts
Hanger Bearer Drop Roll Formed Rod
Long r Side
Cbannel ~-shy ~
---shy
Maximum ~pacing
4 52 3 _ -c Fig 15 - Figs 14 15 16 amp 2J
shy
mmm mmmm 240025 x 25 x 16 40 x 20 x 15 8 240040x20x15 40x 20 x 15 10 240040 x 20 x 1~510 40 x 20 x 15
shy
I
40 x 40 x 15 40 x 40 x 15 24001001 to 1500 I 10
Table 9 Hangers and Supports - circular horizontal ducts
Longer Side Hanoer Split Clips Maximum spacing Drop Roll f-ormed and Wrap-round Rod ~hannel Hang r
2 3 4I Fig 1920 amp 22Fig I
mm mmmm mm mm 25 x 25 x 15 IIp to 355 8 40 x 3- --1-_ 2400
2400
2400 2400
70x 6
40 x 5 SOx 5
40 x 20 x 15 40 x 20 x 15 40 x 40 15
10 10 10
356 to 600 601 to 1000 1001 to 1500
19
DW154 Spccijicutioll for Plastics Ductwork
147 Protection specification Any special coatingpaint Unless otherwise stated all support shall be finishes for protection against hostile manufactured in material as specified in this environments shall be advised by the designer
SUPPORT BEARERS
~ 14 Flg16 Inverted profile
angle I ~lIed steel
channel (alternatives) Fig 15 Profile channel (alternatives)
TYPICmiddotAL VERTICAL DUCT SUPPORTS Flat bar clipStiffening frame Outline ofinsulation stiffening frame or tlanged joint (if applicable) or flanged joint
Stiffening framc or flanged Joint
~~-I ( ee notes 10) I
r--~ -++- ~--4==J===4~---
Fig 17 Vertical rectangular ducts Fig18 Vertical circular ducts
The support bearer which depending on ducti tructural opening size could be either channel or angle section may be ll1ilised in any of the following arrangementsshy
a) To support the underside of a flat bar clip in halves (circular)
b) To support the underidc of either the stiffening frame oftbe flanged joint ofaoy duct section
c) To support either a stiffening frame Or a flanged joint below nsing drop rod srudding
20
DW154 Spediraiml for Plastics Ductwork
Arrangement of bearers and hangers (to be read in conjunction with Table 8 amp 9
wbich list material sizes relative 10 duel izes)
KEY Limits refer to actual duct size - insulation is additional - Typical
attachmentv -Atta hment t strucUlrcI to strucUlrc
I I
I - Flat Bar
I - Drop rod or - utlinc of lllddmg In ulillwn (if
applicable)
Alternative 7 drop rod or rt------------ 1 studdmg q I
I I Rectangular
ii i n 1
Fig 21 Rolled or profiled bearer Limit oncFig 19 Wrap-round hanger Limit 55 DIA
V v Drop rod orAllernaUC 1 1 tudding
drop rod or 1
-- -- 1studding and elded bas 1
I I0 -_
Limit 355 DIA Frg 22 Split clips Limit 1500 DIAFig 20 Flat strap hanger amp split clips
21
DW154 Specification for Plastics Ductwork
6PA deElned in J62 appropriate to the airflow pressure acoustic temperature and corrosion
General
15 ACCESSl SPECTION OPENINGS
151 General These are for inspectionservici ng on 1y
HVCA publication DWIl44 Part 7 - General Section 20 sets out the requirements for access applicable to this specification
152 Cleaningmaintenance Designers shall take specialist advice and then stipulate their requirements for the periodic internal cleaningmaintenance of ductwork and of the consequent need for adequate access for specialist cleaning equipment including the size type and locationfrequency of the actual access openings required
Appendix D sets out guidance notes for the consideration of cleaning access and also makes reference to the HVCA publication TR 17 Guide to Good Practice Cleanliness of Ventilation Systems which covers the su~ject
in greater detail
Note A majority of in tallations in which plastic ductwork is used are considered to have a nigb operational risk potential and provision of access should address this
16 REGULATI G DAMPERS
161 General Balancing dampers and control dampers are elements inserted into an air di tribution system or element of an air distribution sy middottem Balancng dampers permit modification of the air resistance of tbe system and consequently cbanging of the airflow rate Control dampers control tlle airflow rate and may in addition provide low leakage closure of the airflow
The deigner shall specify damper locations taking into consideration that good design practice requires a minimum of five times the diameter or width of the shortest side of uninterrupted flow between plant connections and the damper and select the damper type as
characteristics
1611 Balancing damper To achieve the required distribution of air in the ductwork system at inlets andor outlets for [hi purpose the damper blades are set and Jocked manually in position between fully open and fully closed
1612 Control damper To secure dynamic control of the air now in the ductwork system In thi function the damper will always be power actuated and may require to be modulated between fully open and fully closed and to be capable of taking up any position between these extremes In the fully open position the damper should have a minimum pressure drop In the fully closed position it will not necessarily achieve a complete shut off
162 Types of airflow control dampers Airflow dampers of various types are available for specific purposes as follows
1621 Single - blade dampers Single-blade dampers shall consist of a si ngle pi voted blade cOlllained withjn a casing or section of ductwork The blade shall be adjustable tbmugh a nominal 90 angle by means of a quadrant or similar operating mechanism Where automatic control of the damper is required the spindle shall be extended to enable a powered actllator to be mounted
Single-blade dampers shall have a maximum duct width of 400 nUll and a maximum duct height of 400 mm for rectangular ducts and for circular ducts a maximum diameter of 400 mm
1622 Multi-blade dampers Multi-blade dampers shall consist of a number of pivoted blades contained within a casing The blades shall be
22
DW154 Sedicalirm for Plastics Ductwork
adju table through a nominal 90deg angle simultaneously by intershyconnected linkage or gears connected to a quadrant or similar operating mecbanism Where automatic control of a damper is required a spindle shall be extended to enable a powered achlator to be mounted
There is no restriction on the size of duct in which multi-blade dampers or damper assemblie may be u ed Where dampers are required for blade lengths in excess of 750 mm the blades should be suitably reinforced or supponed 0
individual damper blade should exceed 200 mm in width
1623 Iris dampers Lris dampers shall consist of a nUlllber of radialty interconnected blades which open or close within a casing with duct COlll1cctions The blade shall be simultaneously adjusted by a quadrant or similar operating mechanism
Iris dampers shall be installed as specified by the manufacturers operating and installation instructions where the product is unidirectional with regard to airflow
lris dampers are available for circular ducts only in diameters up to 250 mm (it should be noted that the damper casin i appro)(imately twice the diameter of the duct)
1624 Backdraught dampers Air pressure operated uni-directional rectangular (single or multi-blade) with adapters if fitted to circular ducts
1625 Slide and blast gate dampers A damper [lsed as a shut off facility with an externaJ Lide bousing allowing the blade configuration to be fuJly inserted to fully extended for maxiDlUlll air flow
163 Construction
1631 Materials All products shall be protected against cOHosion as necessary and supplied in a fully finished condition as specified by the designer
1632 Dampers used in low and medium pressure systems The following recommendations apply to dampers forming an integral part of ducrwork with pressure classifications A and B air leakage limits
The dampers shaH be constructed to minimise distortion and prevent jammin in operation Th blade shall be sufficiently rigid to minimise movement when in the locked pOSitiOLl
The blades shall be securely fixed to the operating mechanism All balancing dampers shall have a locking device located on the outsid of the case and shall giv clear indication of the actlwl blad position All penetrations of the duct shall be fitted with suitable seals where necessary
1633 Dampers used in high pressure systems Regulatino- dampers used in duc[work sy tems to pressure cJassification C shall meet tbe construction requireshyments specified in 1631 and 1632 with operating mechanisms out of the air-stream
1634 Proprietary types of damper The use of any specific type of proprietary damper shall be confirmed by the designer In all cases proprietary dampers shall meet the relevant requirements of thi specification
1635 Damper casings Duct damper casings hall be constructed to meet th mllllmum
23
DW154 SpeciJimlioll for Plastics Ductwork
leakage Iim its sp cified for th c1uctwork ystem to which tbey are installed
In order to apply the square metre leakage calculatio as detailed in DW143 A Practical Guide to Ductwork Leakage Testing the reference casing area ball be taken as the perimeter ize of lh damper IDultipli d by the equi alent length of Imetr eg an 800 mm x 400 mm duct damper hall have a surface area for casillg leakag p donnan calculated as follow (2 x 08) + (2 x 04 x I
=24m2 casing area
Other pelforlllance ancl rating test methods for damp f and valves are specified in ISO 5129 and BSIE 1751 and are referenced belm a) Leakage past a closed damper
alve BSIE 1751 b) low ratepre sure requirement
characteri t cs BSIE 1751 c) Operational torque le ring
BSEN 1751 cl) Thermal transfer testing
BSIEN 17 I e) Reg nerated sound power levels
ISO 5129
164 Installation Dampers shall be imaalled in accordance will) any re Ievant ISO EN or British Standard 10 aJ bUT lcling regulation and national code of practice as well as the manufacturers recommendations
17 FIRE DAMPERS AND INT MESCENT SLEEVES
171 General Damper or sleeves arc requiTed on duct y~telll where the designer has -tjpulated the
duct wiU penetrate a fire compartment in the majority of application tbermopla ti ductwork is ugtecl where contamlDated corro ive or otherwise exceptional fumes are concerned it is preferable to use tire damp r which are externalJy mounted ie of the intmnescent operated crush typ
24
72 Fit-e rating The damper assembly should have a fUT
resi tance ratin o equal to that of the fir ban-jer it penetrate and ball be fire tested and rated to the timetemperature curv of B 476 Part 20 and 22
173 Intumescent sleeve At the time of writing this specification qualified test results were available for rectangular dampers and circular dampers up to 55 mm diamet r Manufacture have indicated that they are able t provide speci fications for other size and diameters This infonnation should be confirmed b th de igner Various type are available includino
tho e incorporating ruechanical closing plate and those operated anI by expanded iJllUme c nt media
In all ca es fire damp rs and intnmeBcen leeves shall be supplied and in taUed in
accordance with the manufacturer iJlStructioos and COSHH a essm nt
174 Other types Fire dampers of mious types are availabl for specific purpose~ ee HVCA publication DW144 The de igner should )lot (hat materials for con lt1Jction bould be uitablc for the par1icular application
ALL C SES FIRE DAMPERS AND fNT MESCENT SL _VES SHALL HE S PPLTED AND INSTALLED IN A ORDA CE WITH Tf--IE MANUshyPACTURERS STRUCTTONS AND COSHH ASSESSMENT
18 FLEXIBLEEXPANSION dOINT CONNECTIONS
181 General ploperties Tbe material u ed for flexibleexpan ion iojnt~
mu t meet the design r requirements for temperature air pressllrelfe resistance applicable to pl astic duct sy tem vibration and noi e br akout when incorporated into a jointconnection and shall comply ith lh standard of air-tigbtne specifi cl for the duct work sy tem of which it fOlms part (See Figs 23 24 5 26 27 amp 28 for typical con truclion clelai Is
DW154 SJecilimtol for Plastics Ductwork
Expansion joints
Fig23 Moulded bellows type (rectangular and circular)
Fig24
~F aiblc sleeve
__ liding sleeve
~~~~
Sleeve type (circufar)
Fig 25
AIRFLO
COnlinuou~
weld~
Flexible Iceve
PV A HOWN pp SE BACKING FLATS AS FIG 2
Sliding lee c Co1linuou
weld
Flanged sleeve (rectangular and circular)
25
DW154 Specificatiol for Plastics Ductwork
Flexible con ections
Fig 26 Flexible sleeve with clips (UPVC and PP)
--__ Flexible I eve
I
I
I CODn clioD to plant ~
Band clip
Fig27 Welded flexible sleeve (UPVC only)
Plastic)sed PVC slceve ~-- onll11uo1sly welded
onrreclion to planl ~
Fig28 Flanged flexible connection (UPVC and P )
t sp dally moulded flexible flanged connCClitlll
boil
C)nneclion to plant ~
26
DW154 Specificotiol for Plastics Ductwork
182 LOClt1tion Flexible joint are typicltllly lIsed at building expansion joint and fan inletsoutlets Any others required should be indicated on the de ign drawings Care should be taken to maintain alignment across jointsconnections
183 Length Flexible Jomts shall be kept as short as pra middottieable above a minimum eft ctive length of SO mm In no ca e shall a flexible joint exceed 250 mm in lengtb
184 Connections to rectang a ducts With flanged rectangular connections Ule tlexible material shall be held in pLace with flat pIa tic strip of not less U1an 6 mm thick ltlttached to the flanges using uitabJe fixings The more heavy weight type of fleAible mateLial may also be obtained formed into a channel ection with corners fitted to give a neat air tight j int For pigot connections the Be ible material shall b held in place with flat pIa tic trips n t less than 6 mm thick
t 85 Connections to circular ducts With tlanged circular connections the flexibl material shall be held in place with flat plastic backing strips or proprietary clip bands with screw or toggle fast ners
186 Welded flexible connections (Rectangular and Circular) Where the parent and llexibl material are from imilar ba ed products they can be joined to the duct u ing the welding method described in Section 823
19 PROTECT VE FINISHES
191 nles otherwise stated all ductwork shall be mallllfactured in mat fial as pecified in tbis specification Any special coatingpaint fmishes to be provid d by the duct work contractor sball be advisd by th de igner
20 CONNECTIONS TO BUILDING OPENINGS
201 Fanning and finishing building op nings are not the repoJlsibjlity of the duftw( rk contractor and the note that follow are for guidance purpo e only
2011 Openings in brick block or concrete walls shall have inset frames to provide a suitable means of fixing grille louver masking flanges or the tlanged ends of ductwork The illset frames shall be conslnlcted to maintain the structural int grity of the wlll and where applicable cavities shall be suitably lined
2012 Openin s in dry linino partItIons shall have inset frames a 2011
2013 Openjngs in cladding walls and roofs shall have flaoged leevesframes to provide a suitable means of fixing a 2011
2014 Horizontal and vertical opening xposed to oLltside atmo phere hall
be provided with a suitable weathering fini h at the external face especially where profiled cladding is used
2015 Timber framed op nings are not permitted In fj re compart ment barriers
202 Ductwork connections to building openings hall have a flange of suitable profile to permit practical fixing to the openillg frame In selecting the profile consideration shall be given to Tabl~s 2 and 10 in this specitication relating to duct ize and rating Gasket strip or sealant shall be ltlpplied between the tJaoge and building op ning frame
21 DISCHARGEEXHAUST TERMINAL
21 Tbese shall be vertical open ended and designed to meet and comply with current r gularions on contaminated flue The designer hall ensure that the de ign and perf rmance i suitable for its intended purpose Examples of some typical terminal designs are SbOiD in Figbull 102 10 bull 104 amp 105
27
DW154 SpedjimioTl for Plastics Ductwork
22 THERMAL INSULATION
221 The provision and application of thermal insulation to ductwork is not the responsibility of the ductwork contractor
222 Where ductwork is required to be preshyinsulated the specification should be agreed with tbe designer
223 Where the temperature of the air within the duct promotes condensation on the exterior surface of the duct and cause moisture penetration througb the thermal insulation vapour scaling may be required and in this case the most important requirement is to limit penetration of the seal
The extent of any vapour sealing of ductwork thermal insulation and the support method to be u ed must be clearly pecitled in advance by the designer
224 For detailed information on the thermal insulation of ductwork reference should be made to BS 5422 1990 which covers the specification for thermal insulation materials on pipes ductwork and equipment (in the temperature range -40degC to +700degC) and BS 5970 1992 which is a Code of Practic for Thermal Insulation of Pipework and Equipment (in the temperature range -lOOdegC to +870degC)
23 FIRE RETARDANT FINISHES ON PLAST C DUCTWORK
231 The designer should note tbat ductwork constructed to DW154 has no teted fire rating or information see Appendix C
24 REINFORCEMENT OF DUCTS WITH GRP LAMINATE
241 General Where ductwork is required in larg T izes than are covered by Tables 2 4 6 amp 7 or with the increased strength sometimes necessary for industrial use external reinforcement is normally pwvided by applicatioD of glass fibreresin laminate
GRP systems will bond satisfactorily with standard UPVC sheet but for pp it is
nece sary to use a specially prepared sheet with a glass fabric backing incorporated dOling manufactllfe
The detailed techniques of fabrication using GRP are outside the scope of this speci lcation but the following notes are offered for guidance of ductwork fabricators
242 Materials
2421 Quality The laminate is made up of polyester resin complying with BS 3532 and glass fibre complying with BS 3496 or BS 3749 The nominal ratio of resin to glass fibre should be 7030 by weight
2422 Minimum properties The laminate shall comply with the followiog mini mum pbysical properties
Tensile strength - 70 MNm Tensile modulus - 7 Gl m Flexural strength - 140 M Im Bond strength (hetween laminate and substrate Not less than 7MNm Bmcol hardnes Not le s than manufacturers specification
The GRP reinforcement educe the expansion of the parent material but the resultant stre ses arc well within rhe strength of the bond However the Iinear thermal expansion curve shown in Figs 34 amp 35 will serve as a guide
Surface resistivity electrkal propcltles and acoustical propertie are similar to the relevanl unreinforced materials The fire retarding properties of GRP may be improved by the use of specialisl laminating resin
2423 Forms available GRP Laminate should be built up from the separate materials ie resin aod glass fibre in the form of chopped
I strand mat or spray ravings
28
DW154 Spcification for Plastics Ductwork
2424 Workshop conditions Polyester resuls are sensItIve to lmperature and the workshop hould b maintained at a temperature of herween 20deg and 25degC HiOh relative humidities and damp onditions should be avoided A good rate of air change must be pro icled pJeferably by m chanical ventilation
2425 Storage of materials Resin and urin o agents shouJd be stored in dark cool condirions away from the working area and in confonnit with statutor requireshyments for tJle middottorage of flarmnable liquid Because of Ule Limited torage lif of the unmixed resin and curing a eot mal lials ~hould be ch eked before use to enLlfe that they are within the manufacturer pe ified sh If life (usually ix month from the dm of manufacrure)
Glass fi re should be stored separately und r clean dry conditions
243 Surface preparafon
2431 UPVC To achieve the specified bond strengtll the urface to which the GRP is applied mut first be thoroughly cleaned and then etched either by mechanical means or by the use of a suitable solvent
2432 pp with glass fabric backing To achieve the specified bond middottrength the fabric backing must be thoroughly impregnated Witll resin
244 Mixing the materials for use The re in 1 a three part mix compri lng base I sin hardener and accelerator The manufactur rs pecj[ied proportions are critical and th llUxmg sequenc pecified must be meticulously foUowed
The resin has a very limited life after mixing and before u e It is dependent on the characteri tics and bulk of th resin the alllount of hardener the degree and method of acceleration and the workshop onditions
245 Methods of application
2451 General The mixed resin may be applied by hand or b pray c1epoition The operation must b completed within the gel time of th y tern and tbe laminat fully cOI1olidated to achi v the phy ieal properties pecified
2452 Hand lay-up The duct surface i coated by hand with resin Llsing a brush and a mar of gla fibp orked in until full consolidation achieved Th proc is repeated untiJ th requird thicknes i obtained
2453 Spray depo Won The duct surface is coated WiUl re in by spray gun with the chopped glass roving added through a separate nozzle The full thickne i obtain d in layer with con olidation of each layer by hand roller
246 Construction
2461 General M ini mum COllst ructional requireshyments are pe itied ill Tabl 10 for rectangular and Table 1J for circular dUClS
2462 Joints and stiffeners Fig 29 30 31 32 amp 33 hoI TOSS
joint and tiffener for reinforced UPVC and PBPP duct
247 Worki g practices The fabrication of ductwork pecifiecl ill thi document i not affected by the addition of GRP
29
DW154 SfJcdJicatiOt for Plastics Ductwork
Table 10 Minimum constructional requirements shy
Longer Side Minimum Sheet Thicknes and
GRP Reinforcement
UPVC FBIPP 1 2 3
mm mm mm Up to 1000 3 plus 3 plus
06 kgm2 06 kgOIl GRP GRP
1001 to 2250 45 plus 3 plus 06 kgm 12 kgm
GRP GRP
2251 to 3000 45 plus 6 plus 12 kgm 12 kgm
GRP GRP
Cross Joints
UPVCFBPP 4
mm socket amp spigot
as Fig 30 or flanged as Fig 29
75 x 9 flange welded on both sides as Fig 29
75 x 9 tlange welded on both sides as Fig 29
rectangular GRP reinforced ducts
SlifTeners Maximum Spacing Between
JointsSljffeners UPVCIFBIPP UPVCFBPP
5 6 mm mm
75 x 9 flat 800 as Fig 31 or
50 x 50 x 5 plastic or MS inverted angle as Fig 32
or tormer as Fig 33
75 x 9 flat 600 as Fig 31 or
50 x 50 x 5 plastic or MS inverted angle as Fig 32
or former as Fig 33
75 x 9 flat 600+shyas Fig 31 or 50 x 50 x 5 plastic
or MS inverted angle as Fig 32
or former as Fig 33
Note 1 On rectangular duct up to 400 mm longer side no stiffeners are required 2 Applies to Tables 10 amp I I For COlJstructional operating temperature limits refer to Part 2 clause 5A 3 Tables 10 amp II apply to all pres ure classes up lo ]500 Pa
Table 11
Diameter
1 III
lJp to 1000
1001 to 1750
1751 to 2500
Minimum Sheet Thickness and
GRP Reinforcement
UPVC FBPP 2 3
mm mm 3 plus 3 plus
06 kgm 06 kgm GRP GRP
45 plus 3 plus 06 kgm2 18 kgm
GRP GRP
6 plus 6 plus 12 kglm2 18 kgm1
GRP GRP
Cross Joints
UPVCFBPP 4 III
socket amp spigot as Fig 30 or flaoged as Fig 29
75 x 9 flange welded on both sides as Fig 29
75 x 9 flange welded 00
both sides as Fi 29
inforced ducts
Maximum Spacing Between
JointsStiffeners UPVCIFBPP
6 mm 2400
800
600
Stiffencrs
UPVCFBPP 5
mm 50 x 9 flat as Fig 31
75 x 9 flat as Fig 31 or former as Fig 33 75 x 9 tlat as Fig 31 or t()rmer as Fi 33
ote On extruded tube tip to 600mm diameter no stiffenergt are required
30
DW154 Specificatioll for Plastics Ductwork
G - Cross joints and tiffeners
Fig 29 Flange Joint Fig32 Stiffener shy inverted angle
M artiPfCuQkbdd erttpObri) Wl111 RP tlddtlt
_- GRPloliu] lh~
Fig 30 Socket and spigot joint Fig33 Stiffener shy use of former
Fig 31 Stiffener Flat
I Pv FlPP ~ ~lmJaDUA1) d
OMrlQ rrnall 1( tQlS
25 STANDARD COMPONENT DRAWINGS AND ABBREVIATIONS
251 The illustrations in this section not only highlight where applicable geometric limjtations for the de ign and manufacture or ductwork components but also recommend
standard drawing representation terminology and abbreviations for both duetwork components and some of the more commonly used ancillaryplant items
252 Designers and surveyors should note that bills of quantities should provide a full description
3)
---
v
DW154 Spcc(fim(ml for Plastics Ductwork
Fig 34 Linear Thermal Expansion
u c 0 N ro 0)
b 0)
S
sect0
5 oS cl) 0)
~
on ~ ltl
c U
-30 -20 -10 0 10 20 30 40 50 60 70 80 90 TEMPRATURE C
~ V
-
~~c_ ~
~V
V ~
-7 ~
-- ~V ----
v
-6
+14
+12
+10
+8
+6
+4
+2
0
-2
--4
ig 35 Typical Design Stress tor UPVC and P
7
6
r shy 5E
-c E----0 4t) VJ 0)
ci5 0Jl 3
~
0)
Cl
2
1
o
UPVC
1
000
1
1
pp
- r-- shy r----- shy - t--shy I
__0
-30 -20 -10 0 10 20 30 40 50 60 70 80 90 TEMPERATURE C C
Note Figso 14 amp 35 shaded area refers to GRP reinforced duct
32
DW154 Speciicfltirm for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - REC ~NGULAR
Splilt~r Posilion W-mm pliucr
A B c 40]--QOO 1 W - -
601-1000 1 W4 Wf2 -
1001-1800 3 WI W3 W2
FIG DRAWING DETAfiS
tU]36 ATI Straight Duct with socket and spigol joint
rn [037 Straight Duct with flanged joints
[I []38 Straight Duct with flanged joints
rkJ Short Radius Bend
39 Applies to any augl and for duct up to 400 n11n wide
Minimum (I1m31 radills = 100 mm
Medium Radius Bend (a illustrated)
[kJ Applies to any angle
40 Long Radiu Bend Similar but radius = W
Throlll radius = W2 Applies to any angle
- Short Radius Bend with plitlers
I -shy -shy u co - t lt Li--_ 41 t 0 ~ I I I
~ I
L 1W
Minimum waal radius = 100 mm Splitters not required in bend angle less than 45deg
42 QJ1 Square Bend with turning vanes ij
3
DW154 SP(L~ficatioll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - RECTANGULAR
FIG DRAWl G DETADS
43
~
I v
L L Radius Tee with internal deflectors
44
~ Radiussed Twin Bend
45
Imiddot
er Swept Branch
46 U-
Sqoare Tee with Turning Vanes
47
~ f
Breeches Piece
48 0 y l Piece
34
DW154 Specificatioll for Plastics Ductwork
STANDARD COMPONENT RAWINGS - ECTANGULAR
55
54
51
50
53
52
49
FIG
~MX
RAWlNG
DmiddotMAX
EfjMAX
Minimum throat rndius = 100 mm
Rectangular shy Round Transformatioll
Eccentric Taper 225deg max in either plane Spliller are required for angles greater than 225deg and hould bi eet the angle between any side and duct centreline
DETATLS
Angled Offset
OUset Taper Splitters are required for angle greater than 22 0
and shoold bi eet the angl between any side and dUCI centrelinc
Mitred Offset
Concentrk Taper 2250 max in ither plane SpUtters are required for angle greater than 225deg and should bisect the angle between any side and duel c ntreline
Radiussed Offset
35
DW154 Splcilcuthm for Plastics Ductwork
STANDARD COMPONENT DRAWINGS ~ RECTANGU AR
Branch ducl DimCllsions widlh (W) (A)
urnl mm up lO 200 75
300 100 400 125 600 150
Ocr 600 200
FIG DRAWlNG DETAILS
56 poundplusmni~~ Rectan~lar - Flat Oval Transformation
57 [ Square Branch
58 er Angled Branch
Branch dUCI Dimensions wfdth (W) (A)
[- mm mm59 3shy Shoe Branch Up (0 200 75
--shy AIshy + 300 100
400 125
450 MAX 600 150
Over 600 200
Branch duct DimensIOn
rP X width (W) A)
60 - 1--shy _
~ mm mm
Bell Mouth Branch pto 200 75 300 100 t 400 125
600 150 Over 600 200
0=0 61 -
~ Bell Mouth
- shy T 4-5deg M x
--I 1-shy
TJ
62 X I ] I
Tele-scopic Joint I Illustrated with flangeL
X63
SBD Single Bladed Damper
36
---
DW154 Spedicatioll for Plastics Ductwork
STANDARD OMPONENT DRAWINGS - RECTANGULAR
DRAWING DETAILSFIG
64 on-Return DamperNRD shyshy
shyXbull
Multi-Leaf Damper Can be piggoted or flanged oppo cd or parallel blade
Alternative controls areshy
q p [gtshy
J HD65 Hand
~MD otori ed
PO Pneumalic
L-lt
l 13G 66 Blast Gate DamperX X
FireSmoke DampersSleeves
211r Ratinggtshy----
L_-
---
----
r----
Ir-- shy
IL- _-l
2hr
With i tallation frame
67 41 r Rating
4hr
Smoke damper SD
Intumc cent Sleeve L-d
37
DW154 Specijicutiolt for Plastics Ductwork
FIG
68
69
70
71
STANDARD COMPONET DRAWINGS shy REC ANGULAR
DRAVING DETAILS
gtshy Access Openings
AP 6 Access Panel - Rerno able
w [ ~ Access Door - Hinged
I ~le Inspection Cover
le -I reg -lt
~X X Flexible Connection
~ Drop Cheeked Radiussed Twin Bend
U Drop Cheek Bend
I
72 Air Flow SymbolX
38
DW154 Specifim[ioll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - ECTANGULAR
FIG DRAWING DETAILS
73
74
75
76
77
Q
Q
rp---t
~
V- I Ir---I
JL --11
THE ABOVE DETAILS TYPICAL PLENUM
Air Terminal Plenums
Plenum with side connection
Plenum with top connection
Cover plate with connection
Special plenum with connection
elescopic conn ction in direction of air flow
39
DW154 SpecijicotiOll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG
78
79
80
81
DRAWING
-23~---pound3-(MALE) (FEMAJE)
-t=j--_j(--d-shy
--L
~ THROAT RADI S= D AS T NDARD
e ~
THROAT Rjf)lU = D A MU)
DETAILS
Straight Duct With male and female connectors
Straight Duct With flange joint and slip joint
Bend MouldedIFormed Applies to any angle ego 30deg45deg60deg90deg Medium radius bend as illustrated Long radius similar but throat radius 0
Segmented Bend 90deg four section minjmum as illustrated
Other Angles 60deg = 3 sections 45deg = 3 sections 30deg = 2 sections
I
i
40 shy
DW154 Speciicafinll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG DRAWING DETAlLS
82 Segmented Twin Bend Radius = D2 max
May also be fabricated from tube
83 Equal Tee MouldedIFormed
84 -~ 1in Bend MouldedIFormed
85 Taper Concentric 1 0 as iUu trated Eccentric 30deg iJJcLuded angle
86 Short Taper
41
DW154 SpcUicatol1 for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG DRAWING DETAILS
87 30 max Offset
Angle Branch
Bran h dUCI Dimcnsions dia (D) lA)
Shoe Branch mm mm 88 Cl
Off rectanguJur Up 10 200 75 lOO 10 400 125
- 00 150 Over 600 200
Bl1IllCh duct DimenlOns din (D) (A
~-$a-Conical Branch mm mm
89 Also acceptable with Up 10 200 r
full conical surface 300 10
400 125
END VrE -shy 600 150 Over 600 200
90
m 75
100 12 150 200
mm Up to 200
_ 300 400
600 Over 600
iUtred Branch
Shoe Branch
J-L----U ~ Bell oulh Branch
ENDV1EW
93
92
91
42
DW154 Specificatiol for Plastics Ductwork
STANDARD OMPONENT DRAWINGS - CIRCULAR
FIG
94
DRAW G
I
~ 30deg 090deg
Breeches Piece
DETAILS
95 amp-----~ Blank End
~-----p Multi-Leaf Damper Can be piggolcd or fianged opposed or parallel blade
Alternative controls areshyri=-+- L-T~
I
---
LT~
I r- -
-+1
J HO Hand96
bMD Molori cd
PD Pneumatic
tl-shy bull
Single Bladed Damper 97 ~ saD
on-Return Damper Vertical application only 98 m~D
43
DW154 Sf1tcificatioll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG
99
100
101
102
DRAWING
$ I-
2hr
1 4hr
SD
~v I I
CO TINENTAL COWL
DETAILS
Iris Damper
Fi reS moke Dam persSleeves
2hr Ratillg
With installation frame
4br Rating
Smoke damper
Intumescent Sleeve
Access Openings
Access panel - removable
Access door shy hinged
fnspection cover
Discharge Continental Cowl
44
DW154 Sp(Cii(ltJll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
DRAWINGltIC DETAns
-
I
I
~
I I I High Velocity Discharge Terminal 103 I
I
I I
J I I 1 ~--
Offset Stack Discbarge Terminal 104 1
~ I e --(-
I
N
I
I
I~
I I Vertical Oischarge with Weather Cowl 105 I
--1--1 I
I
GAPI I
RTl AL DISC) lARGE WITH W ATIIER COWL
45
DW154 SpecUicatoll for Plastics Ductwork
STANDARD COMPONE T DRAWINGS - PLA TEQUIPMENTIMISCELLANEOU
FIG DRAWING DETAILS
106 ~~~ Rectangular Attenuator
107 ~- Circular Attenuator
108
~ Beod Attenuator
109 J ~(f) Heating Coil
110 J ftte Cooling Coil
III Jc[ Electric Heating Coil
112 X F
Humidifier
113 [H XX Axial Fan
114 ~fB1famp Noo-standard Ductwork Cross hntchillg (of any separate type) indicates by reference to a key any non DVil54 ductwork system
115 2llIIIIJIIIIIll Flexible Ductwork
46
DW154 SJeCUicll(iol1 for Plastics Ductwork
TABLE 12 - STANDARD ABBREVIAT ONS
ABBREVIATION FLL
AD Acces Door
AFF Axial Flow Fan
AHU Air Handling nit
All Aluminium
AP Acess Panel
AT Attenuator
AV Air enninal Unit
BE 81ank nd
BQ Blast ate Damper
CC Cooling Coil
CF Centrifugal Fan
CTA Cross alk Attenuator
CVU Constant Volume Unit
DP Drain Point
EEC Electric Heating Coil
El Expansion Joint
FAl Fresh Air Inlet
FA From Above
FB From Belo
fBPP Fabric Backed Polypropyl-ne Sheet
Flexle Flexible Connection
lexfD Flexible Du t
C False Ceiling CO an oil Unit
fD Fire Damper
FFL Finished Floor Level
FJ Flanged Joint
FOAM Rigid Polyurethane Self xtinguishing Foam
FOB Flat on Bottom
FOT Flat on Top
GAM Galvanised after ManufacttrJc
GRP Glass Reinforced Plastic
GSS Galvanised Sheet Steel
HC Heating oil
HD and controlled Damper
HH Hand Hole
HL High Level
HVD High Velocity Discharge
IC Inspection Cover
ID lri Damper
IFS Intumescent Fircleevc
47
DW154 Specification for Plastics Ductwork
TABLE 12 - STANDAR ABBREVIATION CONTINUED
ABBREVIATION
IU
L
tv1D
MS
NRD NTS
OBO
OE
PHD
PD
PP
PP
PRD
PVC
RFC
RSC
R
SBO
SO
S1 TST
SSL
TA
TB
TO TJ
TP
TV
TV
OS
UPVC
S
V
VAV
50 RSA
FULL
Induction Unit
Low Level
Motor controlled Damper
Mjld Steel
on Return Damper
at to cale
Opposed Blade Damper
Open End
Parallel Blade Damper
Pneumatic controlled Damper
Polypropylene
Self xtinguishing Polypropylene
Pressure Relief Damper
Polyvinyl Chloride
Rolled Form Chamlel
Rolled Steel Channel
R fUnit
Singl Blade Damper
Smoke Damper
Slip Joint
Stainl t el
tructural Slab Level
To Ab vc
To Blow
Top Down (In Direction of Flow)
Telescopic Joint
Test Point
TU111iog Vane
Top Up (In Direction of Flo )
Voles Otherwise Stated
Unpl3sticisecl Polyvinyl Chloride
Underside
Ultra Violet Light
Variable Air Volume
Rolled Steel Angle (Vith Size)
48
DW154 SJeriiflllioll for Plastics Ductwork
A2 DUCT PRESSUREAPPE DXA Ductwork con truct d to DWIl54 will bebullbullbullbullbullbullbullbullbullbullbullbullbullbull
Air Leakage From Ductwork To be read in conjunction with DW143 A practical guide to Ductwork Leakage Testing
CAUTION As highlighted ill both this docul1lenr and DW14 I lot ellough emphasis can be placed 01 the fact that except for high pressure class C the much more stringent ductwork constructional standard brolght about b the general acceptance of DW154 have irtlally negated the requirement for leakage-testing It is essential lO realise lhat except where it is mandatory this doclllllelll is nOl an endors ~lIlent of the rourine testing of ducts bllt purely a guide to outline the procedures for cononnity with the air leakage limits ill Table l Where the specified methods of assembly and
A3sealing of dlcls are u ed a vi ual inspection wil ordinarily sl~fll e for ver(iatioll of a well engineered and a ceptahfy airtight COl1strucrioll WHERE NOT MANDATORY DUCT LEAKAGE TESTING IS GENERALLY AN UNJUSTIFIED AND SUBSTANTIAL EXPENSE
A1 INTRODUCTION L akage from ducted air distribution systems is an Lmportant consideration in the design and operation of ventilatjon and air conditioning middotystems A ductviork t)ystem tbat ba limited air leakag within defiucd limits wiH cnsUft
that tile design characteristics of the sytem can be maintained It wilJ also ensure that energy and operatLonal cosb are maintained at optimum levels DucLwork constlucted and Ulstalled in accordance with DW154 should minimise a level of air leakage that it) appropriate to tll operating static air pre sur in tile system
A4However it is recouuised that tbe environment in wtJich middotystems are installed is not always conducive to achieving a predictable level of quality in term of system ajr leakage and it is therefore accepted that designer may sometimes require tlle ystem to be tested in part or in total It should be ecogni ed that the testing of duct systems add a ignificant cost to the installation and incur some extra tjm within the programme (Se 47 and 64 re mandatory te-sting)
manufactured to a structural standard that is compatible with the system operating pressure There are three classes of duct con truction to eorre pond with the three pre ure clas meations Class A Lo pressure ducts suita le for a maximum positive operating pressure of 500 Pascal and a maximum negative pressure of -500 Pascals Class B IVledium pressure ductmiddot suitable for a rnaxilnuJJl positive operafjn o pressure of 1000 Pascals and a maxllnum negative pre sure of -750 Pa cal Class C High pre sure ducts suitable for a maximum po ilive operating pressur of 2000 Pa cals and a maximum negativ pres ur of -750 Paltcals
LEAKAGE FROM DUCTWORK Leakao-e front pia tic air ducts occur at the joint~ and is therefore proportional to the total surface area orthe du twork in th system Tb level of leakage i imilarly related to tIle air pres ure in th du t system and whilst there LS n precis formula for calculating the level of air los it i generally accepted that leakage will increase in proportjon to pressure to rbe pOvver of 065 The effect of air leakage from high pressure velocit ductwork is critical tn terms of system perfomlan dege energy consumption and the risk of high frequency noise as ociated with leakage These problems are le critical with medium pressure 10 ity systems but should be con idered Low pres mevelocity ducts present the lowe~t
ri k in tenn of tbe effect of leakage on the operation of the s stern
SYSTEM LEAKAGE LOSS As there i no di ct relatLonship between th volume of air conv yed and the surface area f the ductwork sy tern required to match the building configuratmn it is difficult to express air leakage a a percentage of total air volume Similarly the operating pressure will vary throughollt lh 3 system and a leakage is related to pre me the calculations ar comple However it is generally ac epted tbat in typical good quaJjty systems the leakage from
49
DW154 Specificatioll for Plastics Ductwork
each class of duct llnd r operating condition will be io the region of CIa S A low pressure 6 Clas B medium pres un 3 Clas C high pressure 2
A5 SPECIFYING AIR LEAKAGE TESTING Re peeting both the co -t and programme implications a sociated with te ling du 1 for leakage the designer may for example indicate that a particular system is te ted as follow
a) High pressure ducts - all tested b) Medium pr ssure duets - 10 of the
ductwork shall be s eet d at random and tested
c) Low pre sure - unte ed In any case where a random te t i elected for medium pre sure ductmiddot the followin c1au~e is suggested for inclusion by the de ign r
The designer hall elect at random a maxirnwlI of 10 of the dUCl system to bt tested for air leakage The duct hall be tested af the pressure recommended in Table J3 for the assifi atiol for the ectiol1 of the ductwork that is to be tested The tests shall be carried Ollt as the work proceeds and prior to the application of thermal insulation In the event of test failure of the randomlY selected section the designer shall have The right to select two La1her e tiolls at random for resting Where succes ive failures are identified there shall be a Tight to require rhl COl11raCWr 10 apply remedial attention to the complete ductwork system Th contractor shall provide documented eviden e of the calculalions used to arrive (1
the allowable 10 I for the section to be tested and the client or his agent shall willess and sign the results of the test
able 13 Air leakage rates
Maximum leakage of duct work Static
prcssUft Low-pressure edium-prc-sure I Iigh-prebull me diJfercntial Class A Class B Class C
1 2 J 4 Pa Litres per second per quare metre of surface area 100 054 018 ZOO 084 028 300 110 037 400 132 044 500 153 051 600 058 019 700 064 021 800 069 023 900 075 025
1000 080 027 1100 1200 1300 1400 1500
029 030 032 033 035
1600 1700 1800 1900 2000
036 038 039 040 042
Note Recommend d mean test presures are highlighted iD bold type with the actual selection being left to tll test operator
50
DW154 Sfeeiieaioll for Plastics Ductwork
A9
A10
and air leakage classification for the y em under test
DESIGNERS CALCULATIONS The designer can middotaJculate with reasonable accuracy the predicted total loss from a ystem by
a) Calculating the operatin presure in each ection of the sy tern
b) Calculating the surface area of the ductwork in each correspondin pre lire s ction
c) Calulating the allowabl~ los at the operating pressure for each ection of the system (see table 13 for allowable leakage figures)
VARIABLE PRESSUR S IN SYSTEMS De igner can achieve significant co t saving by matchina operating pressures throughout the system to constmctional standard and appropriate air leakage testing eO the practice of specifying construction tandards for whole duct sy tems based on fan discharge pre sure may incur unnece sary costs on a project For example ome large sy terns ould well be classiC ed for I akage limits as follows
Plant room risers CJas C Main floor distriblltJou CIa B Low pre sure outlets Cla A
A6 SPECIAL CASES There may be ~itLlations on a project where circumstance dictate thal pecial consideration be given to containing air loss s eg a long mn of duclwork may incur a di -proportjonate level of air 10 s In ca es such as thi example the designer can specify an improved tandard of airtighmess ie 80 of alJo~able 10 s for la B Ju ts The designer sbould not specif a CIa C t sI at CIa s C pressure for a CIa s B ducl
A7 SUGG S ED RANGE OF TES ING
A8 TESTING OF PLANT ITEMS Items of inline pJant (eg Fig 106 to 115) will not normaUy be included in an air I akage test The dllctwork contractor may indud such itelllS in tbe te t jf rh quipm ot has a certificate of COnfOlnlity for Ihe pres ure clas
bull High pressure duct bull Medium pre sure ducts bull Low pre sur ducts bull Exposed extract syst ID bull Ceiling void extract
systems bull Secondary ducts from
VAV or fan coil units bull Flexjble duct bull Final connections and
branches to grille and diffusers
100 test See A5 Untested UDt sted
Untested
Untested Untested
Untested
SI
i
DW154 SJecijicafion for Plastics Ductwork
ig 116 Permitted leakage at various pressures
Leakage in litres per second per square metre duct surface area
Vgt
o ltgt 0 ltgt N
ltgt Cgt
0 0 cc
0 0
~
g =
g ~
c 0
J
ltgt 0 I
~ ] tn
ltgt ltgt
In ol
~ 0 ~ 8 ~
~
c ltgt ltgt
~ CJ
~ ~ ~ ~ 8
0shyij
~ ~ ~ t
ltgt ltgt 00
l
~
~ Q
c C
~ rshy
e ltgt
I 1
I Cgt ltgtv
c Co ~
~~ ~ 10
I
0 Cgt
fJshyq 410 ) 1 ltgt
ltgt N
~ shy ltgt ltgt
~ I 1
c
52
DW154 Specificatio for Plastics Ductwork
Example of a completed test sheet Test No
General
Name of job N~ jC43Pt(r2lef Building Repound ~(~~0
Part 1 - Physical details
a Section of duct work to be tested ~(diffPIfff~el1f3rd Floor
b Drawing Number g91~~ c ssure aSSJ L atlOn V~Jl~IRfYgtg~~lPre Cl T Class C
d Test static pressure -(9 raErq~ ~~~~-~~J~~~ ~~ ~~~~ll
Leakaoe factor 9~-tre3$ecMz I OM REFTOTABLE 13)e b bullbullbullbullbullbullbull
f Surface area of duct under test Q~tJJItetre$ CPROMCALCU TIO BELOW)bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull ampampamp bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull
g ]Vlaxi mum permitted leakage -~ (~i~~0 ~~r~~ ~~~l-~-11~ ~~~Q
Part 2 - Test particulars
a Duct static pressure reading 9QFt~q~ ~ middot~~~1 ~~
b Manufacturer and type of liow measuring d vice (-~~~cJ~Y-9Q7EYg c Range of measurement of now measuring device QtP)OQ~(e~~~0I~~~~1~I~ ~~~~~~W~
d Reading of flm measurin o device pmiddot IFROM RIO)ftscag ~
I (DERlVED [ROM CHART SUPPUED WITH RIG US 0 ud)1e Interpreted air flow leakage rate ~(~~~f~~~ (~l~~~~~~~~~~~~~~~~~I
f Duration ~~~~~norn~allY l~ lnil1Ut~~d~~~ it1~ W~ Date of test ~(lITled ut by Wltll s ed by ~ ~
(~lJ MIJLrr) (Si~rrfltJUYJ
Printed Name 1~g0f~ Printed Name ~~Y~9~ and Company 7jl~~~~~( UJd CompanY AB COII$Itallt8
Width and depth or diameter
Periphery ength Area
millimetreS millimetres metre qL1are metre
800 x 750 3100 1755 5440
600 x 650 2500 557 1193
300 x 300 1200 120 144
305 din 958 700 670
250 dia 785 450 353
TOTAL 8000
53
DW154 Specijilarion for Plastics Ductwork
pA XB
Guida ce No es For he ransport Handling and
Storage of uctwork
avoid damage to adjacent duct panels In somc ca es particularly on con acts calling f r repetitive sizes the use of timber jigs and spacers may be justified Where reduced bulk and greater protection are major factor such as consignments for export transporting ductwork in L shape sections may justify the increa ed ite as embly co ts
It is recommended that before a contract is finalised that consideration is given to the subject of site acces material handling and storage as tbcy havgt a strong influence on the cost efficiency of the overall activity of ductwOlk installation
B3 Handling To minilnise th risk of damage duct sections should be clearly identified and deliveries to site should be closely linked to the installation programme so as to avoid accumulation of
B1 Storage and Handling of Ra Material Material should be stored in suitably designed racking out of direct unJight Where possible the e racks should be metal to earth Edges of cut she t may be harp and protective gloves are advised Wearing teel toe-capped boots is recommended Most pIa tic sheet is manufactured with smootb mfaces andor is suppLied with protective coating Care must be taken to prevent accidental lippag of stacked materials Beiuoshy good electrical insulators the movement of stock unless earthed will allow the build up of stati All stock shapes are chemically stable at normal temperature Whil t some raw materials used in their manufacture may themselves pre ent a toxic hazard once incorporated into the lOck bape they no long r constitute such a hazard and no dermatitic bazard are known nor are any
unfiJied ductwork and minimise double handling It is important to recognise that ductwork panels joint and corners arc susceptible to damage and care must be taken wheu band ling such material through a site During handling individual item of duct work may be liable to light cross sectional deformation until thev become an integral pan of a completed ductwork system Whilst this may temporarily detract from its intended appearance thi deformation will not have any detrimental effect on the functionality of the finally a semblecl system Installation of duct work and asociated plant items ill illevitably involve manual handUng The responsibi Iiry of employers and employees to a ses the risk of personal injury during mallual handling operations is et out in the HS E publication L23 Guidance on Manual Handling Regulations 1992
environmental problems expected 84 Site storage
B2 fransport Large capacity vehicles with high-sided open or closed-top bodies are tlle mo t suitable for the transport of dllctwork Careful consideration should be given to the
Adequate floor space IDust be provided within tbe building for the site storage of ductvork Such storage shalt make due allowance for thc stOf(ne of ductwork in stacks such that access ~ egt
between them is of sufficient width to pennil the removal of item without interference to
unloading of transport on sit a not all siJes b n fit from the material handlino- and access facilities that exi [ in a manufacturing workshop such as crane- fork-lifts or loading bay Site handJiog facilities along with
adjoining sta ks Ductvork components should be positioned so a to avoid crushing Ductwork of small panel size may be stored horizontally however care should be exercised to ensure that tack sizes are limited 10 within
ehicular acce s restrictions may itilluence the type and ize of transport to be uWised
engtlls of ductwork should be positioned 0
the tmctural strength of the duct sections to prevent distortion of the lower sections within the stack
as to avoid crushing Lengths Witll projections such as branches and bends i1anges girths damper quadrauL should be loaded so as to
54
DW154 S1tciic(ltioll for Plastics Ductwork
85 Internal cleanliness of new ductwork The site storage of ductwork introduces the important cODsideration of maintaining the internal cleanliness of the ductwork R feren e should be made to HVCA documentshybull DWffM2 Guide to Good Practice - internal
Cleanliness of New Ductwork Installations If the above conditioDs can not be satisfied consideration should be given by tJle designer to amending the specification to include for Po t Installation Cleaning as covered by tJ1C HVCA documentshybull TRJ17 Guide to Good Practic - Cleanliness
of Ventilation Systems
APPE DIXC
Fi e Retardant inishes C1 Improvement in the fire retardancy of plastic
ducts can be achieved to varying degrees and is wholly dependent llPOll the surface coating laminating resin selected and construction specification adopted In some instances smoke emission is coILSidered equaUy with other speci fication requirernen ts of the materials resistance to ignition and bumjng It is therefore important for design rs to establ ish the clients and officers detailed requirements and not rely on a tbird party interpretation of fire resisting or fire retardant Where possible the specification should refer dir etly to compliance with a British or European Standard identifying the specific sections applicable There are various types of resin and mat rcLnforcements that can achieve a Class 1 surface spread of flame ratin o when tested according to BS476 Part 7 (1987) This test puts materials illto Class I - 4 in descending order of perfoDllance according to the rat and extent of flame spread over their surfac under standard beating conditions Materials should also be tested for flre propagarion to BS476 Part 6 (1989) Tbi tesr measures the amount and rate of heat evolved by the material when subjected to standard heating
conditions Test results are given as an index of Perfonnance (i) whicb is based on three sub indices (iJ (i1) (h) The higher the value of the Index of Performance (i) the greater is the material s contribution to fire growth The higher the value of the sub-index 0) rhe greater the ease of ignition aod flame spread The highest product performance classification as defined in Approved Document B of the Building Regulations is Class O This is acLlieved if a material surface of a composite ploduct i~ either a) composed throughout of materials of
limited combustibility or b) a Class I material which has a tlre
propagation index (i) of not more than 12 and sub-index (i l ) of nor more than 6
01 J Class 0 is not a cla$sif1cation identified in any British Standard test
There are resin system reported to be classified to Class O when tested to BS476 Pcl1S 6 and 7 however designers need to ensure that such sysrems can be applied to their proposed design In propriety resinmat system available the fabrication techniques and COITect application are critical to the integrity of the reinforcing and clas ificatiol1 For example in some systems the u e of a non-fire retardant gelcont on a fire retardant substrate would reduce the classification For further information see HVCA publication DW144 Appendix D
55
DW154 SplCijiClIliol1 for Plastics Ductwork
x Guidance otes For nspectmiddoton Servicing a d
Clean-ng Access Openings
D1 GE ERAL This appendix highlight in ummary fOI111
the acce considerations that hould be made by the design r iD terms of inspection servicing and cleaning Having considered the seop and the design of the dUCI work system relative to the guidelines outlined below the designer should clearly indicate which levels of acces should be incorporated into the manufacture of a new duct work system (See Table 14 and Note I b low it
D2 DESIGN CONSIDERATIONS
D21 In ptction and servicing requireshyments are set out in Section 15 of Lhis specification
D22 Cleaning requirements are set out in the HVCA pubUcation TRl7 Guide to Good Practice Clean Lines of Ventilation Systems and the guide tates The precise location ize and
type of access would be dependent on the type of ductwork cleaning inspection and te ting metbods to b adopted Care protection and standards of cleanliness prior LO cOlllmisionin o
are set out in th AV A publication DWITM2 Guide to Good Practice Internal Cleanliness of New Ductwork Installations and th guide state Wh re specific limits of cleanliness are required ductwork sball be cleaned after installation by a spcialist cleaning contractor It will b in the interests of tht desioner botb financially and practically to cunsider employing a specialist c1eauing contractor at tbe
outset of a contract to internally clean newly installed ductwork prior to bandover This approach would reali e the following benefit shyi) Tb actual numb r of cleaning
access panels could be detennined to suit the method of cleaning to be adopted (This may be 1 s than the maximum requiremen listed under Lev 13 of Table 14)
ii) Clear directions could b given to the ductwork contractor as to tJle size and location of cleaning access panels that are required to be fitted during the mauushyfaclunng pro s
iii) The specialist cleaning operation prior to commi ioning vould enable the cleaning contractor to verify the practical acee requirement for the future cleaning operation associated -vitb a regular maintenance programme
iv) A specialist cleaning operation prior to commissioning would allow the designer to omit from the speeilicatiolJ the DWrrM2 requirem nt for factory sealing protection wipe downs and capping-off
v) Specialist Ieall ill 0 to the measurable standard defin d in TR17 will allow an objective definition of cleanline to be achieved
Car ful consideration must be gIven by the designer to the practl aJ problems associated witb the manufacture and fitting of suitably si Led access panel on small cross section duct and on the circular faces of rouod and flat oval ducts in particular
D23 Special con ideration must be given by the de igner to the practical problems associated with gaining personnel access to heavily congested ceiling areas and multi-la red du twork systems This approach would avoid
56
DW154 Spfciication for Plastics Ductwork
the possibility of access panels being D3 ACCESS 0 IN-LINE EQUIPMENT incorporated into a ductwork system at the This appendix unly covers acc il1spection manufacturing stage that were later found in through the ductwork body adjacent to an item practice to be inaccessible for either ervicing of in-line equipment and not openings in the or cleaning activities equipment itself
able 14 Acce requirements for inspection servicing and cleaning
HVCA PUBLICATIO REFE NeE (uidtgt 10 Gund Prartict
Adjace t OW144 Cleanliness orVcnlillltio S~lcr~ fRjJ7
in-line LeyeJ 1 Level 2 Level 3 ite sequipment pcdionSen lcin~ Section d C1eaniJl( SUn(O)lnspc lion Palle ltk~m_n
2011 (minimum OiL Jubje-ct to duct ~zel (ft~ -Panels
Control Da pcrs One (inspection) 203 One 300 mm x 200 mm Both sid Fire Dampers One (sCTjdJl~) 20211 One 300 0101 x 200 mm One side HeatingCooling Coils One (inspedion) 20213 One 300 mm x 200 mm (lIpstream) Both sides Attenuators (rectangular) None required One 300 mm x 200 mm (downstream) Both sides Attenuators (circular) one retluired One 300 mm x 200 mm (downstream) One side Filter Sections One (inspection) 20212 one required Uoth sides Air Turn Vanes None requjred None required Both sides Changes of Direction None required one required One side In-Duct FansDevices One (inspection) 20213 None required Both sides l
1 In the absence of any indication by the designer only Level ) access will be jncorporated into a new ductwork system
2 Tbe panel izes associated with Lev lis I and 3 acee s ar e middottablished by reference to Section 20 of DW144 and Section 2 ofTRll7 respectively
57
DW154 Speclfifatio for Plastics Ductwork
pA XE
B-bliography Included in this Bibliography are technical pUblications which may be of interest (0 ductwork designers fabricators and erectors and to tho e in the heating ventilatlng air conditioning industries generally nquiric should be made of the relevant organisation at the address quoted Since its publication other addresse contained within 0V154 mav have changed and some pubJicalions may have been superseded
HEATING AND VENTILATING CONTRACTORS ASSOCIATION
4 Palace Court London W2 4JG Telephone 020-7229 2488 Fax 020-7727 9268
Orders fo FlY A Publications Old Matlsion House Eamont Bridge Penrith Cumbria CA 10 2BX (Telephone 01768 864771 Fax 01768 86718) Email hvcapoblicationshvwelfarecouk DWn 44 pe ilicatiun for sheet mctal duclwork (Iow- mediulllshy
and high-pressure) 1998) DWIl4 A practical guide to dUGI ork I akage te ting
(revised 2000) DWII54 Specification for plastic~ duct rk DW171 Guide to good Practice for kitchen venlibtion system DW191 Guide to good pracuce glass fibre ductwoJk DwrrMI Acceptance cheme for new products - Redangolar cro
joint classification Guide to good pra tice - Internal cleanliness of new ductwork installations Guide to good practice for the design for the Installation of lire and smoke uampers
J 1Other puhlications
HampV safely guide 5th edition JS2 Tool box talks JS5 Weldlng Safety booklet JSI9 afety facts bo klet Fact sheets 1-24 2nd edition JS2J COSHH manual volume 1 Advice on compliance with the
regulations 1521A CO I-rH manual volume 2 Asses mcnt h ets JS23 Ri k management manual TR3 BrazinltT and bronze welding of copper pipework cUld sheet
(I 976) TR5 Welding of carbon steel pipework (1980)
TR6 Guide to Good Practice for Site Pre sure Testing of Pipework (19 0) Guide to good practice cleanliness of ventilation Ylem
CHARTERED IN TITUTlO OF BUILDING SERVICES E G EERS Delta House 222 Balham High Road London SW12 9BS rTelephone 020-8675 5211 Fax 020-8675 5449) CIBSE Guide Volume A Design Data Volume B In tallatiol1 and quipment Data Volume C Reference Data
CommlssioniJIg Codes These Codes eover the preliminary checkS eUing to work and regulation of vanous catcgories 0 plan The Codes give a guide to design implications Series A Air Distnbution Systems Series B Boiler Plant
ri s C Automatic Conlrol ystems Cr1es R Refrigerating Sy terns
Sene iN Water Distribution Systems
Technkal Memonllda TM 4 Design Notes for the Middle East TM bull Design otes for Ductwork TM 13 Minimi iog lhc Risk of egiounaires Disease
Research Reports RROI95 Ventilation system hygiene - A review of published
infomlatioo on lhe occurrence and ffects of Olltamination Rl~02J95 Air-to-air heal rec v ry RR0395 rnfluen e of HV C on smoke detectors
ATlONAL ENI [ERING SPECIFICATION LfMITED Southgatc hamber 3739 Southgate Street Winchester S023 9EH (Telephone 01962 842058 Fax 01962 R(8982) BUfLDING S RVICES RESEARCH AND [ ORMATION ASSOCIATIO Old Bracknell Lane West Bracknell Berkshire RG 12 4AH (Telephone Brackl1eU (01344) 426511 Fax 01344 487 -7 )
Application Guides AGln4 De tglJing Vana~le Volume middotylans for KOOnl
iir Movement AG1I91 Commissioning of V Sylcms in Buildings 11 6194 Fire Dampers
B) 94 cntiJalion or KitcneTls
AG389 The Commls ionin of Air Systems In Buildmgs AH2192 Commissioning of Bern - A ~ode of Practice TN2417 I Fire Dampec il) Ventilating Ducl
BEATING VENTILATING A AIR CONDITION G MA UFACTURERS ASSOCIATIO (HEVAC) HEVAC Henley Road Medmenham Marlow Buck SU 2ER (Telephone 01491 578674 ox 01491 575024 Emoimiddot infofetacouk)
Publicatjons Air Diffusion Guide Guide to Air Handling Unit Leakage Testing Guide to Good Practice Air Handling Unit Real Room Acoustic ~ st Procedure Specification for the ertiiicatioll ofAir Filters Method of Test for Water Rejection PerfOnTlatce of Louvrcs Subjected 1(1
Simulated Rainfall Test Procedure for Acoustic Loo cs Specification 10 Floor GrilJes - Types Performan e and Method ofTest Specification for the Determination of the Collection Efficiency of SilJ1d
Trap Louvre Domestic Mechwlical Vclltllalion Systems with Heal Recovery Fan Application Guid
~an and Ouctwork Installation Guide Guide to Fan Noise and Vibration
pecification of Requirements for JallJral Smoke and Heal Exhausl Ventilators
pecification for Powered Smoke and Heat Exhaust Ventilators
Specification of Requirements for Smoke Curtains Design Gujue of Smoke Ventilation for Single Storey Lodustrilll Building~
Including those with Mezzanine Floor and IIi Racked Storage Warehou es - Issue 3
Guidance for the Design of Smoke entilation YSlem for Covered and Undergrollnd Car Parks - lssue 1
Application of SOloke Control Equipment and Syst m Guid to Good Practice - Isue J
58
DW154 Sp(C~tiifitiol for Plastics Ductwork
BRITISH STANDARDS INSTIT TION Sales Department 101 P ntooviLle Road London NI 9ND (felephone 020-78 1 78801)
CP 413 1973 Ducts for building ervices
SS 476 Fire tes on building matenals and lruc(ure
Part 4 19 4 Non-combustibility lest or materials
Part 6 I Fire propagation lest for materials
Part 7 1993 Surface spread of tlarnJ tesls for materia
Part 20 1987 Fir resistance of elements of construction
Part 21 1987 Fire r sistlUlce of loadbeanng elements of construction
Part 22 1987 Fhe istallceofllon-loadbearing elemcllts ofconsttuclion Part 23 1987 Contribution of componcnts to the fire resistance 0 a
structure
Part 24t987 Fire resi lance of wl1lilation ductl
SS 5588 nan 919 0 Fire Precautions III thc desIgn and OOSlnJ lion of buildings
S 729 1971 Hot dip galvanized oatiugs (or irOIl aod stcel articles
BS 1449 Steel plate sheet and Irip
Pan 11991 Carbon steel plate heel and strip Part 2 1983 Stainless steel plate sheer and strip
and
B middotENJOI49-2 996 BSEN 10149- 1991)
BSEN 10131 1992
BSEN22063 Sprayed metal coarings 1994 Protection of iron and steel by aluminium and zinc against
atmospheric cOlosion Irotectiotl of iron and ste I against corro ion and oxishydation at elevared temperatures
BS 353 1981 Glossary of lerms relnting to thermal insulation
BS ISO 1479 Self-tapplngscrewsandmetallicdri c crew
B -lSO 7049
1994
B 4800 1989 Painl colour for building purposes B 4848 l0 rolled structural steel sections
Part4 1972 Equal and unequal angles BS 5422 1990 Specification for the use of therm illuating matcriulS
SS 5720 1979 ode of practice for mechanical veutilating and air C 11shy
dirionin bull in building
l3S PR 12814-1 Bend resting for plasric welds
SS PR 12814-2 Tensile testing for plastic welds
SS PR 13067 Appro altesting for plastic welds
BS PR EN I 100-] Vi ual in pection ofplaslic welds
SHEET METAL AND AIR CONDITIONING CONTR-CTORS NATIONAL ASSOCIATION INC (SMACNA) Headquarters 420 I Lafayeue Center Drive Chanlilly Virginia 2051-1209
Mailing Address pa Box 221230 Cbantilly Virginilt120 153-1230
Telephone (703) 803-2980 Fax (703) 803-3732
Accepted IJJdustry Pl3Gtice for Industrial Duct Constnlelion 197 ) i-rchitecmral Sheet kwl Manual ([993)
Comractors Guide lor Modification 10 ooslruerion Colllraets 1993 Ducted Eleclric Heat Guide for ir Handling Ssrerns (1994)
En~rgy ollservatioD Guidelines (1984) Energy Recovery Equipment yslClllS (199l
Fibrou GIns Duct onS1ntClion Standards (1992)
Fire Smoke amp Radiation Damper In tall Guide for HVA Syst ms (1992) Guide t leel Stack 1(95)
HVA Air Duct Leakage Test Manual (19 ) HVA COlllmissioning lvlanual (1994)
H A Duct Construction Standards-Metal amp Flexible (1995) Addendum 01 (Nov 1997)
HVA Duct Systems Inspection Guide (1989)
HVA ySlems-Application (1986) nVAC ByternS-DLlct D ign (1990)
HVi Systems-Testing Adjusting amp Balancing (1993)
indoor Air Quality Manual (1993) tcheu quipment Fabrication Guidelmes (1990)
Managers Guide for elding (1993)
Rectangular Industrial Duct Cons1TUction Standards (19 0) Round Industrial Duct oustmction Standards (1977)
Sei mic Restraint Manual (1991) (wl Appendix E 1993) SMACNA Ma le Index ()fTechnical Publications (1995) Tbennoplnstic Duct CPY ) Construction Manual 1994)
DEPARTME OF THE ENVIRO MENT (Publications Centre) H Stationery Oflice 5 Nine Elms Lane London SWS 5DR
MampEJ 011972 Electrical in tallat1011 in buildings ( ew Editiou)
IampE 0319 Healing hot and cold wat r steam and gas losla1lations for buildings
M amp - No4 1970 Central heating and hot and cold ~ ateT in tallations for
dwelling
M amp ENo100 1971 Mechanical ventilation for building~
ASSOCIATION FOR SPECIALIST FIRE PROTECTlO As ociation House 235 Ash Road AJdershot Hampshire GUl2 4DD
Telephone OJ25221322 Fax 0 J252 333901
lublicalioos Fire Ratcd and moke Outlet Ducrwork An Industry Guide t Design and InSlalla lioll
HEALTH AND SAFETY EXEC TIVE Rose Court 2 Southwark Bridge London SEl 9HS Telephone 020-7717 6000
TWJ THE WELD G TlTUTE Abington Hall Abington Cambridge CB16AL Telepbone 0 J223 89162
Publication DatJ Oil w~ldll1g of lhermopla lics
59
DW154 wciiwlioll for Plastics Ductwork
A -=--DIX
Factors
Specific gravity shy pp = 091 approx UPVC = 14 approx
Some miscellaneous conversion factors
To convert
Length Inches to millimetres Feet to metres
Multiply by
2540 03048
To convert
Millimetres to inches Metres to feet
vIultiply by
003937 3281
Area Square inches to square millimetres 6452 Square millimetres to square inches 000155 Square feet to square metres 00929 Square metres to square feet 10764
Volume Cubic feet to cubic metres Cubic feet to litres Gallons (UK) to litres
002832 2831 4546
Cubic metres to cubic feet Litres to cubic feet Litres to gallons (UK)
35315 00353
022
Mass Ounces to grams Pounds to kiJograms Tons to tonnes
2835 04536
1016
Grams to ounces Kilograms to pounds Tonnes to tons
003527 2205
09842
Volume flow Cubic feet per minute to cubic Cubic metres per second to cubic
metres per second 0000472 feet per minute 2119 Cubic feet per mIDute to litres Litres per second to cubic feet
per second 04719 per minute 2119
Motion Feet per minute to metres per second 000508 Metres per second to feet per minute 197
Pressure Inches water gauge to millibars 2491 Inches wateJ- gauge to pascals (Pa) 2491 I Pa = I ewton per square metre = 10-2 millibars
60
Heating and Ventilating Contractors Association Esca House 34 Palace Court London W2 4JG
Tel 020 7313 4900
e-mail contact Itvcaorguk web site wwwhvcaorguk
Fax 020 7727 9268
DW154 SpeciiCfllioll for Plastics Ductwork
63 Leakage at various pressures and other 110 mm to 600 mm dia (Dimensional rela tionships tolerances to DIN 8062) Applying the limits specified In Table 1 Appendix A (Table 13) sets out the permitted 74 PPS (Forms aailable) leakage at each of a serie of pressures up tu a maximum for each class Incloded in that 741 Extmded sheet in thickness 3 mm to Appendix is a graphical presentation of the 12 mm (Dimensional tolerance to pre urelleakage relationship DIN 53479)
DWl143 A Practical Guide to Ductwork 742 V series tube in sizes 1] 0 mrn lO 630 Leakage Testing provides detai Is of the basis mm dia and fittings in size I 10 mm for the leakage limits specified in Table 1 to 400 mm dia (Dimenional
tolerances DIN 53479) 64 Air leakage testing
Air Jeakage testing of low and medium 743 All PPS material used hall be pressure ductwork is not mandatory under compatible and comply with DIN tJlis specification Air kakage testing of high 4102 part B and SS 476 part 7 class pressure ductvork t mandatory under this 4 PPS material should not be used for specification and for details of testing external applications vithout suitable procedure refer LO DW143 A Practical Guide protection (See Part 6 section 19) to Ductwork Leakage Testing
744 It should be noted thal PP is not fully 7 MATERIALS compatible wilh PPS
71 Application 75 FBPP (Forms aailable) This specification applies to ductwork constructed from materials as defined below 7 51 Sheet in thickness 3 mm to 9 mm or equal Minimum material thickness is to be taken a a nominal thickness as Tables 267 7 52 Continuous roll form in thickness 2 10 amp 11 AJJ UPVC materials ued shall be mm to 4 mm low flammability selfextinguishing compatible and UV stable with pigment colour to RAL 7 53 This particular material is specifically 7011 and DIN 4802 B 1 designed to be externally reinforced
with GRP (See Section 24) 72 Types
The materials covered by thi specification are 76 UPVCGRP abbreviated herein as foIlowsshy This is a form of composite lamjnate used (UPVC) Unplasticised polyvinyl chloride where improved mechanical trengtb UV (PPS) Self eXlioguihing polypropylene stabilisatiolJ or fire retardence is required (PP) Polypropylene (GRP) Gla s reinforced plastic 77 UPVCIFOAMJGRP (FOAM) Rigid polyurethane self FBPPFOAMfGRP
extinguiShing foam This is a form of composite laminate used (FBPP) Fabric backed polypropylene sheet where insulation andor support is required for
special applications 73 UPVC (Forms available)
8 DUCTWORK CONSTRUCTION 731 Extruded sheet in thickness 3 mm to AND JOINT SEALING
12 mm (Dimensional tolerances to DIN 7748) 81 Ductwork construction
The election of longitudillal cross joint and 732 V series tube in sizes 110 mm to stiffener types within the criteria laid dOT1 in
1AOO mm dia and fittings in siz~ Part 3 amp 4 shall be used as a minimum standard
9
DW154 Spet((icatioll for Plastics Ductwork
82 Joint sealing and sealants 8226 The joint mu t be held in po ition ror at leamiddott 5
821 General minutes A jig should be The integrity of the ductwork used jf nece-ltsary to ensure depends on the successful applicatioll that no twisting force i of tbe conemiddot t jointing metbod appl ied to th joint during
the period 822 Solvent cementing
Solvent cementing a atisfactory 8227 Once made the joint method of jointing circular UPVC should not be exposed to socket anu spigot or leeve joints a undue force for eight certain solvent based cement horn shy hour Tb full strength of geneously bond the PVC surface the jOjJlt is not achieved in providing uitabl joints Solvent less than twenty-four cementing i not practicable with PP hours because of its hioh resi tanc to solvents The procedure recommended OTE SOLVENT CEMENT JOINTING by the cement manufacnJrer should METHODS ARE TOT RECOMshybe followed but the following points ME DED FOR RECTANGULAR are important DUCT SECTIONS
[N ALL CASES S ALA MATshy8221 Clearance between ocket ERlALS MUST BE APPLIED
and spigot must be STRICTLY IN ACCORDA CE minimal because of the WITH THE MANUFACTUR ~RS
lirnited gap filling propshy 11 STRUCTIO SAD OSHH ertie of the cement ASSESSMENT
8222 Inside edges of sockets and 823 Hot air welding utside edge of spigot VC and pp a be welded by
shouJd be lightly chamshy Llsing the hot ga Ifil1er rod meUlOd fered ltmd thoroughly cleaned described helow
8223 Mating urfaces should be 8231 The welding gas can be cleaned using a proprietary nitrooen or compressed air solvent cleaner to remove and shltlll b fIltered free grease and slightly etch the from suspended water oil surface vapour and particulate
matter 8224 The cement should be
applied a quickly a 8232 The filler rods shall be possible to the socket and made from material to r pigot over the full area of compatible with the matshythe mating surface are eriaJ being welded should be taken to avoid the use of excessive 8233 Butt weld joints shall be cement bevelled to an included
angle of 60deg to 90deg and 8225 The posi liolling of the joint where po sibl welds shall
mUSl be achieved immedshy be fully penetrated from iately after the cement i both ide of the work applied aJld surplus cement removed
10
DW154 Specificatiol for Plastics Ductwork
8234 The joint face and the filler rod surfaces must be clean and grease fre and preferably roughened b shyfore welding In particular any deposited filler rod that is charred mu t be scraped away before additional runs are added
8235 The numbers of runs of fi lIer rod shall be sufficient to give a thiekne s of era s section of the veld at least equal to the thiekn s of the sheet
8236 Where high frequency park testing i specified lhi shall be undertaken in accordance with tbe weldshying in tmction handbook
Note A full descriplion of welding method is given in the Welding Institut handboo entitled Data on Welding of Thennoplastic Relevant BS amp CE Standards are prEN 12814-1 amp 2 prE 13067 and prE 13100-1
824 Completion of compo ite laminate joints Following solvent ementing or hot air welding of joints campi tion of any specified external laminate shall
carried out to maintain thebe
825
integrity of the construction (S 8227)
Gaskets These can be fabricated from various materials in the form of a pre-formed roll she t or trip applied between opposing faces of fbnced ross joints It i a visable to select material r commended by th ga ket manufacturer for the pecific appucation intended
PART 3
Rectangula ucts
9 RECTANGULAR DUCT SIZES
91 This specification covers duct size up to a rnLltimum longer ide of I -00 mm Duct size with an a peet ralio greater than 4 I ar not recommended Although they offer no problems of construction they increase friclionaJ resi tance and the pos ibility of Dois
10 CONSTRUCTION
101 General Th minimum constructional requiJement r r UPVC and PPPPS un-reinforced are hown in able 2
102 Longitudinal seams Longitudinal seams should Dot be located at corners or in the underside of the duct
103 Sheet jointing seams Seams shall be joined by continuous filler rod hot air welding or by fl1sion Vi ldiug only other form of jointing are not acceptable
104 Socket and spigot joints Sock t and spigot joints shall be formed by purpoe made double cket pi ces 100 mm long and of the ame thiekne material as the duct welded into position on each standard length of duet forming 50 mm de p sockets prepared and ready for final jointing on site with filler [Od of the ame formulation used for prefabrication (See Table 2)
105 Flanged joints
1051 FJa ges Fabricated flanges shall b con tmeted u ing miniumum of 9 mm thick by 50 nun wide material of matching formulation depending on duel size as hown in Table 2 The flange hall be mounted true and square to the duct surface and w lded on both sides a 103 and Figs 3 4 Alternative con truction Illay be
11
DW154 Spedjicfltiotl for Plastics Ductwork
utilised for attacllment to plant or other equipment
1052 Drillings Drjllings shall be placed to permit clearance to tbe extel11al casing and any reinforcement of tbe ductwork for the application of fastening
1053 Fastenings For nonnaJ application bright zinc plated bolts nuts and vashers hall be Llsed in sizes and pitch centres shown in Tabl 3 Where special conditions prevail consideration of other material finishes such as stainless steel bolpounds nuts and washers may be used In all cases gasket materials as Section 825 shaLL be used
106 Expansion joints Wher the configuration of the ductwork does not provide for movement due to temperature change or where such movement is restricted by branches or attachmenL expansion joints should be specified by the designer (See Section 18 FlexibleExpansion joint connections)
It is the re ponsibilir-y of the designer to identify the positions of any necessary expansion joints hased upon design param ters for the individual systems (See Figs 23 to 25 34 amp 35)
Design ote xamples of expansion joints shown in Figs 23 to 25 are not suitable for movement exceeding 30 mm
107 StilJeners
1071 External stiffeners Shall be fitted as specified in Tables 2 amp 10 and Figs 5 amp 6
1072 I temal stiffeners The u e of internal stiffening or bracing shall be acceptable iJ deemed necesary and approved by the designer (See Fig 7)
11 FITTINGS
111 Standardisation of fiuings The terminology and descriptions of rectangular duct fittings a et out in Section 25 are recommended for adoption as standard practice to provide common terms of reference for desi crners quantity surveyor and ductwork contractors and for those using computer in ductwork design and fabrication
Bend are designated as hard or easy and the e terms as used herein have the folJowin o
meanings
Hard signifies rotation in the plane of tb longer side of the cross ection
Easy signiiies rotation in the plane of the shorter side of the cros section
An example iIlu trating these term ] given in Fig 8
Fitting are fabricated by cutting and welding sheet
112 Stiffeners Shall be as 107 and Tables 2 amp 10
113 Splitters Shall be as shown in Fig 41 and welded as 1003
114 ruing vanes Where square bends are required turning vanes as shown in Fig 9 hall be fitted
115 Branches When fitting branch ducts to a main duct care should be taken to ensure that the rigidity- of the duct panel is maintained in terms of tbe sti ffenillg criteria
116 Change shapes Where a change bape is necessary to acconUllOdate the duct and the cross- ectional area is to be maintained the slope haU not exceed 225deg 011 any side (See Figs 52 to 56) Where a change in shape includes a local reduction in duct cras - ectionaJ area the slope should not exceed ISO on any side and tbe reduction in area should not exceed 20 Where tceper angles are necessary due to ile
12
DW154 Spec([icatirJ1l for Plastics Ductwork
restucllOn splitters shall be provided Taper Transformation pieces from circular 10 square pieces reducers and transformation piec s or rectangular shall be made as long a shall be manufactured from the tbickl1 s of p sible and uJe angl ball be uot mor than material specified for the larger size ducl 225 (Fig 55)
loon Pa 1500 Pa
2 3 4 5 6 mm mm mm mm
3 socket amp spigot - - -or tlanged
as Figs 1 2 3 401 to 600 45 flanged 50 x 9 flat 1200 800
50 x 9 flat welded both sides a Fig 3 as Fig 5
601 to 1000 45 flnged 50 x 9 flat 800 600 50 x 9 flat welded both sides as Fig 3 as Fig 5
1001 to 1500 6 anged 75 x 9 flat 600 600 75 x 9 flat welded botb sides as Fig 3 as FieJ 5
or or 70 x 70 x 9 angle 50 x 50 x 5 angle
as Fig 4 welded both sides as Fig 6
N t For constructional operating temp rature limits refer to Part 2 Clause 54
Longer Pitch Bolt Size
Side max 2
mm 1m mm Up to 400 100 8 with washers 401-600 tOO 10 with washers
601middot1000 100 10 with wash rs 1001-1500 100 10 with oycrsized
washer
13
Table 2 inimum con tructional requi ments - rectangUlar nmiddotreinforce UPVC and pp
Joints Sliffeners Maximum spacinOLonger Side MillirnUlll She t between
Thickness Joint~S(iffi ners
mm Up to 400
DW154 SpedflCiltion for Plastics Ductwork
Cross joint - recta gular ducts
Fig 1 Socket and spigot joint (UPVC and PP)
Conlinuou weld joint on sile onlinuou- wcld
CT~r~T2
Fig 3 Flange joint (UPVC and PP)
ontinuou weld
Fig 2 Socket and spigot joint (UPVC only)
Fig 4 Flange joint (UPVC and PP)
S iffeners - rectangular ducts
Fig 5 Flat Fig6 Angle
Oatim wo]
Fig8 Bends - examples of hardTie rod assembly and easy
Hard
Fig7 With spacers Easy
4
DW154 Speci(uariml for Plastics Ductwork
Fig 9 Turning Vanes
HOWl G TYl AL EXAMPLE OF FOCI G
15
Ma vane length shy 615 mm
Example ofbraemg when V1IIle length exeeed max pennined Ahematively two banks of ncs fixmg the centre rail together at ] 50 mm nrrcs
U~_II---- fixed to dnct wall both CDds
bLEVATION
vane
Maximum distance between centrc oflUming vanes should [Jot exceed 60 mm pitch
DW154 SPCCijicllfiull for Plastics Ductwork
practice to provide common terms ofPA T4 reference for designers quantiry urveyor and
Circular Ducts
12 CIRCULAR DUCT SIZES Th duct sizes [n Table 4 have been selected from the ISO and C standard ranges as the 132 preferreod sizes
Table 4 Circular ducts shystandard extruded tube sizes
133 Extruded tube
ISO Standard Sizes (Nominal Diameter) 11
Wan Wall Thickness Thickness
mm mm mm mm 110 500 4022
I25160 600 50 I25200 630 60
225 25 700 60 13425250 800 63
280 900 70 315
23 23 80
355 1000
25 1250 104 400 32 1400 108 450 35
Note The above sizes are subject to normal manufactl1ring tolerances Other size may be available in varying wall Lhicknesses and subject to test and operational pressure
13 CONSTRue ION
13 General Tllis specification covers duct sizes up to a maximum diameter of 1500 mm The minimum constructional requirements for UPVC amp PPPPS un-reinforced ducts sball be as Tables 6 amp 7
ductwork contractors and tho e using computers in ductwork design and fabrication The requirements for circular duct fittings apply throughout the size ranges covered in this specification
Sheet jointing seams Seams shall be joined either by continuous fLiJer rod hot air welding or by fu ion welding Other forms of jointing are not acceptable
Socket and Sl)igot joints Socket and spigot joints shall be formed by purpose made double socket pieces 100 mm long and of the same thickness material as tJJe duct welded into position on each tandard length of duct forming 50 mm deep sockets prepared and ready for final jointing on ite with PVC adhesive andor fill r rod of the same formulation used for fabrication
Flanged joints
1341 Flanges abricated flanges shall be conshy
structed using minimum of 9 mm thick by 50 mm wide material of matching formulation depending on duct size as shown in Tables 6 amp 7 The flange shall be mounted true and square to the duct surfaces and welded OD both sides a 103 and Fig 12
1342 Drilliogs Drilling ball be placed to permit clearance to the external casing and any reinforcement of the ductwork
1343 Fastenings For normal application bright zinc plated bolts nuts and washers hall
16
For srualler diameters preformed fittings are available otberwise fitting are fabricated from segments of duct or sheet welded together
The terminology and description of circular duct tiltings as set Ollt in Section 25 are recommended for adoption as standard
be used in sizes and pitCh centres shown in Table S Wh re special conditions prevail consideration of other material finishes such as stain le steel bolt nuts and wasbers shall be u ed In all ca cs gasket materials as Seciion 825 shall be USed
DW154 Speciliwriml for Plastics Ductwork
135 Stiffeners
1351 External stiffeners Shall be fitted as specified in Tables 67amp 1 I and Fig 13
1352 Internal stiffeners The use of internal stiffening or bracing hall be acceptable if deemed neces ary and appn ved by the designer
f 36 Expansion joints Where the corrfiguration of the ductwork does not provide for movement due to temperature
Cross joints - circular ducts
change or where such movement is restricted by branches or attachments expansion joints should be fitted (See Section 18 Flexible Expansion joint connections)
It is the responsibiLity of the designer to identify the position of any necessary expansion joints based upon design parameters for the individual systems (See Figs 23 24 2534 amp 35)
Design Note Examples of expansion joints shown are not suitable for movement exceeding 30 mm
Fig 10 Socket and spigot joint (UPVC and PP)
ConLinuous weld joim on ite Ontinuous weld
crlr~l
Fig 12 Flange joint (UPVC and PP)
Continllous wcld
boil
Continuous weld or Solvelll cement
Solvelll ccmcnl joim on sile
Fig 11 Socket and spigot joint (UPVC only)
Stiffeners - circular ducts Table 5 Fastening centres shycircular duct flange jointsFig13 Flat
flat conljnlJou~ly welded Diameter Pitch Bolt Size
max
1 2 J 11
1 shy -~
mm mm mm Up to 600 100 8 with washers
601middot1000 100 10 with washers - ---I
1001middot1500 100 10 with oversized washers
1
Minimum offourfixings
17
DW154 Specifiiutiofl for Plastics Ductwork
Table 6 constructional quiremen s - circular unshy inforced U VC
Diameter Minimum Joints Stiffeners Maximum spa ~in r
Sheet between Thickness Jointsl tiffcners
1000 Pa 1500 Pa
1 2 3 4 5 6 UD mm mm mm mm
UO to 600 3 socket amp spigot as Figs 10 11
or fla ged Fig 12
601 to 1000 45 socket amp spigot 50 x 9 flat 2400 2400 as Figs 10 11 welded bo sides
or Oanged as Fig 13 as Fig 12
1001 to 1500 6 Hanged 75 x 9 flat 1200 1200 as Fig 2 welded both ides
as Fig 13
Applies 10 Tables 6 alld 7
Note 1 For constructional operating temperature limit refer to Part 2 luu 54 2 To allow for conicleration or extruded se lions or fabricated component the materia] tllicknes i hawn a nominal
Table 7 Minimu onstrucfional requirements shy circular un-reinforced PPS and
Diameter Minimum Joints Stiffcners Maximum pacio Sheet between
Thickness Join sStiffener 1000 Pa 150n Pa
I 2 3 4 6 mm m m mm
110 to 500 3 socket amp spigot as Fig 10 or flaoged as Fig 12
501 to 750 45 ocket amp spi~ot
as Fi 10 or Uanged as Fig 12
751 to 1000 6 tlanged 50 x 9 Oat UOO 12 0 as Fig 12 welded nth sides
as Fig 13 1 1 to 1250 6 flanged 75 x 9 flat 800shy 800
as Fig 12 welded both sides as Fig 13
1251to~ flangcd 75 x 9 Oat 600 600 as Fig 12 welded both sides
as Fig 13
18
DW154 Sped(icalirm for Plastics Ductwork
PARTS
Hangers an Suppo ts
14 GENERA
141 Supports are an e sentiaJ part of me ductwork system and their supply and in tallation are normally the responsibility of the ductwork contractor The principl s are a I-rvCA publication DWIl44 Part 6 Section 19 and should be read in conjunction with this document
Design Note Designers may pecify specific requirements wbich will supersede guidance given in DW144
142 Rectangular ducts abl 8 give the- minimum requirements for
hanger and supports for un-reinforced ductwork
143 Circular ducts Table 9 gives the minimum requirements for hangers and upports for uD-reinforced ductwork
144 Vertical d cts The design of supports for vertical duct is dictated by site condition and where practical duc hould be upported at 4000 mm interval or where tbey pa s through a floor (but n ver exceeding 4500 mm) see Figs 17 amp J8
145 External ducts Where ducts are external to buildings and may be ubject to wind loading support should be plac d so as to restrain ide tl1ruSt and should allow axial movement as neces ary It is the respon ibility of me de igner to calculate the effect of the particular prevailing condition and to define any special upport requirement
146 Expansion joints Support shall be designed to permit axial movement only and shall e provided on eitl1er ide of expansion joint
I 1shy
I~
mm -Jp to 400
401 to 600 601 to 1000
Table B Hangers and Supports - rectangular horizontal ducts
Hanger Bearer Drop Roll Formed Rod
Long r Side
Cbannel ~-shy ~
---shy
Maximum ~pacing
4 52 3 _ -c Fig 15 - Figs 14 15 16 amp 2J
shy
mmm mmmm 240025 x 25 x 16 40 x 20 x 15 8 240040x20x15 40x 20 x 15 10 240040 x 20 x 1~510 40 x 20 x 15
shy
I
40 x 40 x 15 40 x 40 x 15 24001001 to 1500 I 10
Table 9 Hangers and Supports - circular horizontal ducts
Longer Side Hanoer Split Clips Maximum spacing Drop Roll f-ormed and Wrap-round Rod ~hannel Hang r
2 3 4I Fig 1920 amp 22Fig I
mm mmmm mm mm 25 x 25 x 15 IIp to 355 8 40 x 3- --1-_ 2400
2400
2400 2400
70x 6
40 x 5 SOx 5
40 x 20 x 15 40 x 20 x 15 40 x 40 15
10 10 10
356 to 600 601 to 1000 1001 to 1500
19
DW154 Spccijicutioll for Plastics Ductwork
147 Protection specification Any special coatingpaint Unless otherwise stated all support shall be finishes for protection against hostile manufactured in material as specified in this environments shall be advised by the designer
SUPPORT BEARERS
~ 14 Flg16 Inverted profile
angle I ~lIed steel
channel (alternatives) Fig 15 Profile channel (alternatives)
TYPICmiddotAL VERTICAL DUCT SUPPORTS Flat bar clipStiffening frame Outline ofinsulation stiffening frame or tlanged joint (if applicable) or flanged joint
Stiffening framc or flanged Joint
~~-I ( ee notes 10) I
r--~ -++- ~--4==J===4~---
Fig 17 Vertical rectangular ducts Fig18 Vertical circular ducts
The support bearer which depending on ducti tructural opening size could be either channel or angle section may be ll1ilised in any of the following arrangementsshy
a) To support the underside of a flat bar clip in halves (circular)
b) To support the underidc of either the stiffening frame oftbe flanged joint ofaoy duct section
c) To support either a stiffening frame Or a flanged joint below nsing drop rod srudding
20
DW154 Spediraiml for Plastics Ductwork
Arrangement of bearers and hangers (to be read in conjunction with Table 8 amp 9
wbich list material sizes relative 10 duel izes)
KEY Limits refer to actual duct size - insulation is additional - Typical
attachmentv -Atta hment t strucUlrcI to strucUlrc
I I
I - Flat Bar
I - Drop rod or - utlinc of lllddmg In ulillwn (if
applicable)
Alternative 7 drop rod or rt------------ 1 studdmg q I
I I Rectangular
ii i n 1
Fig 21 Rolled or profiled bearer Limit oncFig 19 Wrap-round hanger Limit 55 DIA
V v Drop rod orAllernaUC 1 1 tudding
drop rod or 1
-- -- 1studding and elded bas 1
I I0 -_
Limit 355 DIA Frg 22 Split clips Limit 1500 DIAFig 20 Flat strap hanger amp split clips
21
DW154 Specification for Plastics Ductwork
6PA deElned in J62 appropriate to the airflow pressure acoustic temperature and corrosion
General
15 ACCESSl SPECTION OPENINGS
151 General These are for inspectionservici ng on 1y
HVCA publication DWIl44 Part 7 - General Section 20 sets out the requirements for access applicable to this specification
152 Cleaningmaintenance Designers shall take specialist advice and then stipulate their requirements for the periodic internal cleaningmaintenance of ductwork and of the consequent need for adequate access for specialist cleaning equipment including the size type and locationfrequency of the actual access openings required
Appendix D sets out guidance notes for the consideration of cleaning access and also makes reference to the HVCA publication TR 17 Guide to Good Practice Cleanliness of Ventilation Systems which covers the su~ject
in greater detail
Note A majority of in tallations in which plastic ductwork is used are considered to have a nigb operational risk potential and provision of access should address this
16 REGULATI G DAMPERS
161 General Balancing dampers and control dampers are elements inserted into an air di tribution system or element of an air distribution sy middottem Balancng dampers permit modification of the air resistance of tbe system and consequently cbanging of the airflow rate Control dampers control tlle airflow rate and may in addition provide low leakage closure of the airflow
The deigner shall specify damper locations taking into consideration that good design practice requires a minimum of five times the diameter or width of the shortest side of uninterrupted flow between plant connections and the damper and select the damper type as
characteristics
1611 Balancing damper To achieve the required distribution of air in the ductwork system at inlets andor outlets for [hi purpose the damper blades are set and Jocked manually in position between fully open and fully closed
1612 Control damper To secure dynamic control of the air now in the ductwork system In thi function the damper will always be power actuated and may require to be modulated between fully open and fully closed and to be capable of taking up any position between these extremes In the fully open position the damper should have a minimum pressure drop In the fully closed position it will not necessarily achieve a complete shut off
162 Types of airflow control dampers Airflow dampers of various types are available for specific purposes as follows
1621 Single - blade dampers Single-blade dampers shall consist of a si ngle pi voted blade cOlllained withjn a casing or section of ductwork The blade shall be adjustable tbmugh a nominal 90 angle by means of a quadrant or similar operating mechanism Where automatic control of the damper is required the spindle shall be extended to enable a powered actllator to be mounted
Single-blade dampers shall have a maximum duct width of 400 nUll and a maximum duct height of 400 mm for rectangular ducts and for circular ducts a maximum diameter of 400 mm
1622 Multi-blade dampers Multi-blade dampers shall consist of a number of pivoted blades contained within a casing The blades shall be
22
DW154 Sedicalirm for Plastics Ductwork
adju table through a nominal 90deg angle simultaneously by intershyconnected linkage or gears connected to a quadrant or similar operating mecbanism Where automatic control of a damper is required a spindle shall be extended to enable a powered achlator to be mounted
There is no restriction on the size of duct in which multi-blade dampers or damper assemblie may be u ed Where dampers are required for blade lengths in excess of 750 mm the blades should be suitably reinforced or supponed 0
individual damper blade should exceed 200 mm in width
1623 Iris dampers Lris dampers shall consist of a nUlllber of radialty interconnected blades which open or close within a casing with duct COlll1cctions The blade shall be simultaneously adjusted by a quadrant or similar operating mechanism
Iris dampers shall be installed as specified by the manufacturers operating and installation instructions where the product is unidirectional with regard to airflow
lris dampers are available for circular ducts only in diameters up to 250 mm (it should be noted that the damper casin i appro)(imately twice the diameter of the duct)
1624 Backdraught dampers Air pressure operated uni-directional rectangular (single or multi-blade) with adapters if fitted to circular ducts
1625 Slide and blast gate dampers A damper [lsed as a shut off facility with an externaJ Lide bousing allowing the blade configuration to be fuJly inserted to fully extended for maxiDlUlll air flow
163 Construction
1631 Materials All products shall be protected against cOHosion as necessary and supplied in a fully finished condition as specified by the designer
1632 Dampers used in low and medium pressure systems The following recommendations apply to dampers forming an integral part of ducrwork with pressure classifications A and B air leakage limits
The dampers shaH be constructed to minimise distortion and prevent jammin in operation Th blade shall be sufficiently rigid to minimise movement when in the locked pOSitiOLl
The blades shall be securely fixed to the operating mechanism All balancing dampers shall have a locking device located on the outsid of the case and shall giv clear indication of the actlwl blad position All penetrations of the duct shall be fitted with suitable seals where necessary
1633 Dampers used in high pressure systems Regulatino- dampers used in duc[work sy tems to pressure cJassification C shall meet tbe construction requireshyments specified in 1631 and 1632 with operating mechanisms out of the air-stream
1634 Proprietary types of damper The use of any specific type of proprietary damper shall be confirmed by the designer In all cases proprietary dampers shall meet the relevant requirements of thi specification
1635 Damper casings Duct damper casings hall be constructed to meet th mllllmum
23
DW154 SpeciJimlioll for Plastics Ductwork
leakage Iim its sp cified for th c1uctwork ystem to which tbey are installed
In order to apply the square metre leakage calculatio as detailed in DW143 A Practical Guide to Ductwork Leakage Testing the reference casing area ball be taken as the perimeter ize of lh damper IDultipli d by the equi alent length of Imetr eg an 800 mm x 400 mm duct damper hall have a surface area for casillg leakag p donnan calculated as follow (2 x 08) + (2 x 04 x I
=24m2 casing area
Other pelforlllance ancl rating test methods for damp f and valves are specified in ISO 5129 and BSIE 1751 and are referenced belm a) Leakage past a closed damper
alve BSIE 1751 b) low ratepre sure requirement
characteri t cs BSIE 1751 c) Operational torque le ring
BSEN 1751 cl) Thermal transfer testing
BSIEN 17 I e) Reg nerated sound power levels
ISO 5129
164 Installation Dampers shall be imaalled in accordance will) any re Ievant ISO EN or British Standard 10 aJ bUT lcling regulation and national code of practice as well as the manufacturers recommendations
17 FIRE DAMPERS AND INT MESCENT SLEEVES
171 General Damper or sleeves arc requiTed on duct y~telll where the designer has -tjpulated the
duct wiU penetrate a fire compartment in the majority of application tbermopla ti ductwork is ugtecl where contamlDated corro ive or otherwise exceptional fumes are concerned it is preferable to use tire damp r which are externalJy mounted ie of the intmnescent operated crush typ
24
72 Fit-e rating The damper assembly should have a fUT
resi tance ratin o equal to that of the fir ban-jer it penetrate and ball be fire tested and rated to the timetemperature curv of B 476 Part 20 and 22
173 Intumescent sleeve At the time of writing this specification qualified test results were available for rectangular dampers and circular dampers up to 55 mm diamet r Manufacture have indicated that they are able t provide speci fications for other size and diameters This infonnation should be confirmed b th de igner Various type are available includino
tho e incorporating ruechanical closing plate and those operated anI by expanded iJllUme c nt media
In all ca es fire damp rs and intnmeBcen leeves shall be supplied and in taUed in
accordance with the manufacturer iJlStructioos and COSHH a essm nt
174 Other types Fire dampers of mious types are availabl for specific purpose~ ee HVCA publication DW144 The de igner should )lot (hat materials for con lt1Jction bould be uitablc for the par1icular application
ALL C SES FIRE DAMPERS AND fNT MESCENT SL _VES SHALL HE S PPLTED AND INSTALLED IN A ORDA CE WITH Tf--IE MANUshyPACTURERS STRUCTTONS AND COSHH ASSESSMENT
18 FLEXIBLEEXPANSION dOINT CONNECTIONS
181 General ploperties Tbe material u ed for flexibleexpan ion iojnt~
mu t meet the design r requirements for temperature air pressllrelfe resistance applicable to pl astic duct sy tem vibration and noi e br akout when incorporated into a jointconnection and shall comply ith lh standard of air-tigbtne specifi cl for the duct work sy tem of which it fOlms part (See Figs 23 24 5 26 27 amp 28 for typical con truclion clelai Is
DW154 SJecilimtol for Plastics Ductwork
Expansion joints
Fig23 Moulded bellows type (rectangular and circular)
Fig24
~F aiblc sleeve
__ liding sleeve
~~~~
Sleeve type (circufar)
Fig 25
AIRFLO
COnlinuou~
weld~
Flexible Iceve
PV A HOWN pp SE BACKING FLATS AS FIG 2
Sliding lee c Co1linuou
weld
Flanged sleeve (rectangular and circular)
25
DW154 Specificatiol for Plastics Ductwork
Flexible con ections
Fig 26 Flexible sleeve with clips (UPVC and PP)
--__ Flexible I eve
I
I
I CODn clioD to plant ~
Band clip
Fig27 Welded flexible sleeve (UPVC only)
Plastic)sed PVC slceve ~-- onll11uo1sly welded
onrreclion to planl ~
Fig28 Flanged flexible connection (UPVC and P )
t sp dally moulded flexible flanged connCClitlll
boil
C)nneclion to plant ~
26
DW154 Specificotiol for Plastics Ductwork
182 LOClt1tion Flexible joint are typicltllly lIsed at building expansion joint and fan inletsoutlets Any others required should be indicated on the de ign drawings Care should be taken to maintain alignment across jointsconnections
183 Length Flexible Jomts shall be kept as short as pra middottieable above a minimum eft ctive length of SO mm In no ca e shall a flexible joint exceed 250 mm in lengtb
184 Connections to rectang a ducts With flanged rectangular connections Ule tlexible material shall be held in pLace with flat pIa tic strip of not less U1an 6 mm thick ltlttached to the flanges using uitabJe fixings The more heavy weight type of fleAible mateLial may also be obtained formed into a channel ection with corners fitted to give a neat air tight j int For pigot connections the Be ible material shall b held in place with flat pIa tic trips n t less than 6 mm thick
t 85 Connections to circular ducts With tlanged circular connections the flexibl material shall be held in place with flat plastic backing strips or proprietary clip bands with screw or toggle fast ners
186 Welded flexible connections (Rectangular and Circular) Where the parent and llexibl material are from imilar ba ed products they can be joined to the duct u ing the welding method described in Section 823
19 PROTECT VE FINISHES
191 nles otherwise stated all ductwork shall be mallllfactured in mat fial as pecified in tbis specification Any special coatingpaint fmishes to be provid d by the duct work contractor sball be advisd by th de igner
20 CONNECTIONS TO BUILDING OPENINGS
201 Fanning and finishing building op nings are not the repoJlsibjlity of the duftw( rk contractor and the note that follow are for guidance purpo e only
2011 Openings in brick block or concrete walls shall have inset frames to provide a suitable means of fixing grille louver masking flanges or the tlanged ends of ductwork The illset frames shall be conslnlcted to maintain the structural int grity of the wlll and where applicable cavities shall be suitably lined
2012 Openin s in dry linino partItIons shall have inset frames a 2011
2013 Openjngs in cladding walls and roofs shall have flaoged leevesframes to provide a suitable means of fixing a 2011
2014 Horizontal and vertical opening xposed to oLltside atmo phere hall
be provided with a suitable weathering fini h at the external face especially where profiled cladding is used
2015 Timber framed op nings are not permitted In fj re compart ment barriers
202 Ductwork connections to building openings hall have a flange of suitable profile to permit practical fixing to the openillg frame In selecting the profile consideration shall be given to Tabl~s 2 and 10 in this specitication relating to duct ize and rating Gasket strip or sealant shall be ltlpplied between the tJaoge and building op ning frame
21 DISCHARGEEXHAUST TERMINAL
21 Tbese shall be vertical open ended and designed to meet and comply with current r gularions on contaminated flue The designer hall ensure that the de ign and perf rmance i suitable for its intended purpose Examples of some typical terminal designs are SbOiD in Figbull 102 10 bull 104 amp 105
27
DW154 SpedjimioTl for Plastics Ductwork
22 THERMAL INSULATION
221 The provision and application of thermal insulation to ductwork is not the responsibility of the ductwork contractor
222 Where ductwork is required to be preshyinsulated the specification should be agreed with tbe designer
223 Where the temperature of the air within the duct promotes condensation on the exterior surface of the duct and cause moisture penetration througb the thermal insulation vapour scaling may be required and in this case the most important requirement is to limit penetration of the seal
The extent of any vapour sealing of ductwork thermal insulation and the support method to be u ed must be clearly pecitled in advance by the designer
224 For detailed information on the thermal insulation of ductwork reference should be made to BS 5422 1990 which covers the specification for thermal insulation materials on pipes ductwork and equipment (in the temperature range -40degC to +700degC) and BS 5970 1992 which is a Code of Practic for Thermal Insulation of Pipework and Equipment (in the temperature range -lOOdegC to +870degC)
23 FIRE RETARDANT FINISHES ON PLAST C DUCTWORK
231 The designer should note tbat ductwork constructed to DW154 has no teted fire rating or information see Appendix C
24 REINFORCEMENT OF DUCTS WITH GRP LAMINATE
241 General Where ductwork is required in larg T izes than are covered by Tables 2 4 6 amp 7 or with the increased strength sometimes necessary for industrial use external reinforcement is normally pwvided by applicatioD of glass fibreresin laminate
GRP systems will bond satisfactorily with standard UPVC sheet but for pp it is
nece sary to use a specially prepared sheet with a glass fabric backing incorporated dOling manufactllfe
The detailed techniques of fabrication using GRP are outside the scope of this speci lcation but the following notes are offered for guidance of ductwork fabricators
242 Materials
2421 Quality The laminate is made up of polyester resin complying with BS 3532 and glass fibre complying with BS 3496 or BS 3749 The nominal ratio of resin to glass fibre should be 7030 by weight
2422 Minimum properties The laminate shall comply with the followiog mini mum pbysical properties
Tensile strength - 70 MNm Tensile modulus - 7 Gl m Flexural strength - 140 M Im Bond strength (hetween laminate and substrate Not less than 7MNm Bmcol hardnes Not le s than manufacturers specification
The GRP reinforcement educe the expansion of the parent material but the resultant stre ses arc well within rhe strength of the bond However the Iinear thermal expansion curve shown in Figs 34 amp 35 will serve as a guide
Surface resistivity electrkal propcltles and acoustical propertie are similar to the relevanl unreinforced materials The fire retarding properties of GRP may be improved by the use of specialisl laminating resin
2423 Forms available GRP Laminate should be built up from the separate materials ie resin aod glass fibre in the form of chopped
I strand mat or spray ravings
28
DW154 Spcification for Plastics Ductwork
2424 Workshop conditions Polyester resuls are sensItIve to lmperature and the workshop hould b maintained at a temperature of herween 20deg and 25degC HiOh relative humidities and damp onditions should be avoided A good rate of air change must be pro icled pJeferably by m chanical ventilation
2425 Storage of materials Resin and urin o agents shouJd be stored in dark cool condirions away from the working area and in confonnit with statutor requireshyments for tJle middottorage of flarmnable liquid Because of Ule Limited torage lif of the unmixed resin and curing a eot mal lials ~hould be ch eked before use to enLlfe that they are within the manufacturer pe ified sh If life (usually ix month from the dm of manufacrure)
Glass fi re should be stored separately und r clean dry conditions
243 Surface preparafon
2431 UPVC To achieve the specified bond strengtll the urface to which the GRP is applied mut first be thoroughly cleaned and then etched either by mechanical means or by the use of a suitable solvent
2432 pp with glass fabric backing To achieve the specified bond middottrength the fabric backing must be thoroughly impregnated Witll resin
244 Mixing the materials for use The re in 1 a three part mix compri lng base I sin hardener and accelerator The manufactur rs pecj[ied proportions are critical and th llUxmg sequenc pecified must be meticulously foUowed
The resin has a very limited life after mixing and before u e It is dependent on the characteri tics and bulk of th resin the alllount of hardener the degree and method of acceleration and the workshop onditions
245 Methods of application
2451 General The mixed resin may be applied by hand or b pray c1epoition The operation must b completed within the gel time of th y tern and tbe laminat fully cOI1olidated to achi v the phy ieal properties pecified
2452 Hand lay-up The duct surface i coated by hand with resin Llsing a brush and a mar of gla fibp orked in until full consolidation achieved Th proc is repeated untiJ th requird thicknes i obtained
2453 Spray depo Won The duct surface is coated WiUl re in by spray gun with the chopped glass roving added through a separate nozzle The full thickne i obtain d in layer with con olidation of each layer by hand roller
246 Construction
2461 General M ini mum COllst ructional requireshyments are pe itied ill Tabl 10 for rectangular and Table 1J for circular dUClS
2462 Joints and stiffeners Fig 29 30 31 32 amp 33 hoI TOSS
joint and tiffener for reinforced UPVC and PBPP duct
247 Worki g practices The fabrication of ductwork pecifiecl ill thi document i not affected by the addition of GRP
29
DW154 SfJcdJicatiOt for Plastics Ductwork
Table 10 Minimum constructional requirements shy
Longer Side Minimum Sheet Thicknes and
GRP Reinforcement
UPVC FBIPP 1 2 3
mm mm mm Up to 1000 3 plus 3 plus
06 kgm2 06 kgOIl GRP GRP
1001 to 2250 45 plus 3 plus 06 kgm 12 kgm
GRP GRP
2251 to 3000 45 plus 6 plus 12 kgm 12 kgm
GRP GRP
Cross Joints
UPVCFBPP 4
mm socket amp spigot
as Fig 30 or flanged as Fig 29
75 x 9 flange welded on both sides as Fig 29
75 x 9 tlange welded on both sides as Fig 29
rectangular GRP reinforced ducts
SlifTeners Maximum Spacing Between
JointsSljffeners UPVCIFBIPP UPVCFBPP
5 6 mm mm
75 x 9 flat 800 as Fig 31 or
50 x 50 x 5 plastic or MS inverted angle as Fig 32
or tormer as Fig 33
75 x 9 flat 600 as Fig 31 or
50 x 50 x 5 plastic or MS inverted angle as Fig 32
or former as Fig 33
75 x 9 flat 600+shyas Fig 31 or 50 x 50 x 5 plastic
or MS inverted angle as Fig 32
or former as Fig 33
Note 1 On rectangular duct up to 400 mm longer side no stiffeners are required 2 Applies to Tables 10 amp I I For COlJstructional operating temperature limits refer to Part 2 clause 5A 3 Tables 10 amp II apply to all pres ure classes up lo ]500 Pa
Table 11
Diameter
1 III
lJp to 1000
1001 to 1750
1751 to 2500
Minimum Sheet Thickness and
GRP Reinforcement
UPVC FBPP 2 3
mm mm 3 plus 3 plus
06 kgm 06 kgm GRP GRP
45 plus 3 plus 06 kgm2 18 kgm
GRP GRP
6 plus 6 plus 12 kglm2 18 kgm1
GRP GRP
Cross Joints
UPVCFBPP 4 III
socket amp spigot as Fig 30 or flaoged as Fig 29
75 x 9 flange welded on both sides as Fig 29
75 x 9 flange welded 00
both sides as Fi 29
inforced ducts
Maximum Spacing Between
JointsStiffeners UPVCIFBPP
6 mm 2400
800
600
Stiffencrs
UPVCFBPP 5
mm 50 x 9 flat as Fig 31
75 x 9 flat as Fig 31 or former as Fig 33 75 x 9 tlat as Fig 31 or t()rmer as Fi 33
ote On extruded tube tip to 600mm diameter no stiffenergt are required
30
DW154 Specificatioll for Plastics Ductwork
G - Cross joints and tiffeners
Fig 29 Flange Joint Fig32 Stiffener shy inverted angle
M artiPfCuQkbdd erttpObri) Wl111 RP tlddtlt
_- GRPloliu] lh~
Fig 30 Socket and spigot joint Fig33 Stiffener shy use of former
Fig 31 Stiffener Flat
I Pv FlPP ~ ~lmJaDUA1) d
OMrlQ rrnall 1( tQlS
25 STANDARD COMPONENT DRAWINGS AND ABBREVIATIONS
251 The illustrations in this section not only highlight where applicable geometric limjtations for the de ign and manufacture or ductwork components but also recommend
standard drawing representation terminology and abbreviations for both duetwork components and some of the more commonly used ancillaryplant items
252 Designers and surveyors should note that bills of quantities should provide a full description
3)
---
v
DW154 Spcc(fim(ml for Plastics Ductwork
Fig 34 Linear Thermal Expansion
u c 0 N ro 0)
b 0)
S
sect0
5 oS cl) 0)
~
on ~ ltl
c U
-30 -20 -10 0 10 20 30 40 50 60 70 80 90 TEMPRATURE C
~ V
-
~~c_ ~
~V
V ~
-7 ~
-- ~V ----
v
-6
+14
+12
+10
+8
+6
+4
+2
0
-2
--4
ig 35 Typical Design Stress tor UPVC and P
7
6
r shy 5E
-c E----0 4t) VJ 0)
ci5 0Jl 3
~
0)
Cl
2
1
o
UPVC
1
000
1
1
pp
- r-- shy r----- shy - t--shy I
__0
-30 -20 -10 0 10 20 30 40 50 60 70 80 90 TEMPERATURE C C
Note Figso 14 amp 35 shaded area refers to GRP reinforced duct
32
DW154 Speciicfltirm for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - REC ~NGULAR
Splilt~r Posilion W-mm pliucr
A B c 40]--QOO 1 W - -
601-1000 1 W4 Wf2 -
1001-1800 3 WI W3 W2
FIG DRAWING DETAfiS
tU]36 ATI Straight Duct with socket and spigol joint
rn [037 Straight Duct with flanged joints
[I []38 Straight Duct with flanged joints
rkJ Short Radius Bend
39 Applies to any augl and for duct up to 400 n11n wide
Minimum (I1m31 radills = 100 mm
Medium Radius Bend (a illustrated)
[kJ Applies to any angle
40 Long Radiu Bend Similar but radius = W
Throlll radius = W2 Applies to any angle
- Short Radius Bend with plitlers
I -shy -shy u co - t lt Li--_ 41 t 0 ~ I I I
~ I
L 1W
Minimum waal radius = 100 mm Splitters not required in bend angle less than 45deg
42 QJ1 Square Bend with turning vanes ij
3
DW154 SP(L~ficatioll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - RECTANGULAR
FIG DRAWl G DETADS
43
~
I v
L L Radius Tee with internal deflectors
44
~ Radiussed Twin Bend
45
Imiddot
er Swept Branch
46 U-
Sqoare Tee with Turning Vanes
47
~ f
Breeches Piece
48 0 y l Piece
34
DW154 Specificatioll for Plastics Ductwork
STANDARD COMPONENT RAWINGS - ECTANGULAR
55
54
51
50
53
52
49
FIG
~MX
RAWlNG
DmiddotMAX
EfjMAX
Minimum throat rndius = 100 mm
Rectangular shy Round Transformatioll
Eccentric Taper 225deg max in either plane Spliller are required for angles greater than 225deg and hould bi eet the angle between any side and duct centreline
DETATLS
Angled Offset
OUset Taper Splitters are required for angle greater than 22 0
and shoold bi eet the angl between any side and dUCI centrelinc
Mitred Offset
Concentrk Taper 2250 max in ither plane SpUtters are required for angle greater than 225deg and should bisect the angle between any side and duel c ntreline
Radiussed Offset
35
DW154 Splcilcuthm for Plastics Ductwork
STANDARD COMPONENT DRAWINGS ~ RECTANGU AR
Branch ducl DimCllsions widlh (W) (A)
urnl mm up lO 200 75
300 100 400 125 600 150
Ocr 600 200
FIG DRAWlNG DETAILS
56 poundplusmni~~ Rectan~lar - Flat Oval Transformation
57 [ Square Branch
58 er Angled Branch
Branch dUCI Dimensions wfdth (W) (A)
[- mm mm59 3shy Shoe Branch Up (0 200 75
--shy AIshy + 300 100
400 125
450 MAX 600 150
Over 600 200
Branch duct DimensIOn
rP X width (W) A)
60 - 1--shy _
~ mm mm
Bell Mouth Branch pto 200 75 300 100 t 400 125
600 150 Over 600 200
0=0 61 -
~ Bell Mouth
- shy T 4-5deg M x
--I 1-shy
TJ
62 X I ] I
Tele-scopic Joint I Illustrated with flangeL
X63
SBD Single Bladed Damper
36
---
DW154 Spedicatioll for Plastics Ductwork
STANDARD OMPONENT DRAWINGS - RECTANGULAR
DRAWING DETAILSFIG
64 on-Return DamperNRD shyshy
shyXbull
Multi-Leaf Damper Can be piggoted or flanged oppo cd or parallel blade
Alternative controls areshy
q p [gtshy
J HD65 Hand
~MD otori ed
PO Pneumalic
L-lt
l 13G 66 Blast Gate DamperX X
FireSmoke DampersSleeves
211r Ratinggtshy----
L_-
---
----
r----
Ir-- shy
IL- _-l
2hr
With i tallation frame
67 41 r Rating
4hr
Smoke damper SD
Intumc cent Sleeve L-d
37
DW154 Specijicutiolt for Plastics Ductwork
FIG
68
69
70
71
STANDARD COMPONET DRAWINGS shy REC ANGULAR
DRAVING DETAILS
gtshy Access Openings
AP 6 Access Panel - Rerno able
w [ ~ Access Door - Hinged
I ~le Inspection Cover
le -I reg -lt
~X X Flexible Connection
~ Drop Cheeked Radiussed Twin Bend
U Drop Cheek Bend
I
72 Air Flow SymbolX
38
DW154 Specifim[ioll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - ECTANGULAR
FIG DRAWING DETAILS
73
74
75
76
77
Q
Q
rp---t
~
V- I Ir---I
JL --11
THE ABOVE DETAILS TYPICAL PLENUM
Air Terminal Plenums
Plenum with side connection
Plenum with top connection
Cover plate with connection
Special plenum with connection
elescopic conn ction in direction of air flow
39
DW154 SpecijicotiOll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG
78
79
80
81
DRAWING
-23~---pound3-(MALE) (FEMAJE)
-t=j--_j(--d-shy
--L
~ THROAT RADI S= D AS T NDARD
e ~
THROAT Rjf)lU = D A MU)
DETAILS
Straight Duct With male and female connectors
Straight Duct With flange joint and slip joint
Bend MouldedIFormed Applies to any angle ego 30deg45deg60deg90deg Medium radius bend as illustrated Long radius similar but throat radius 0
Segmented Bend 90deg four section minjmum as illustrated
Other Angles 60deg = 3 sections 45deg = 3 sections 30deg = 2 sections
I
i
40 shy
DW154 Speciicafinll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG DRAWING DETAlLS
82 Segmented Twin Bend Radius = D2 max
May also be fabricated from tube
83 Equal Tee MouldedIFormed
84 -~ 1in Bend MouldedIFormed
85 Taper Concentric 1 0 as iUu trated Eccentric 30deg iJJcLuded angle
86 Short Taper
41
DW154 SpcUicatol1 for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG DRAWING DETAILS
87 30 max Offset
Angle Branch
Bran h dUCI Dimcnsions dia (D) lA)
Shoe Branch mm mm 88 Cl
Off rectanguJur Up 10 200 75 lOO 10 400 125
- 00 150 Over 600 200
Bl1IllCh duct DimenlOns din (D) (A
~-$a-Conical Branch mm mm
89 Also acceptable with Up 10 200 r
full conical surface 300 10
400 125
END VrE -shy 600 150 Over 600 200
90
m 75
100 12 150 200
mm Up to 200
_ 300 400
600 Over 600
iUtred Branch
Shoe Branch
J-L----U ~ Bell oulh Branch
ENDV1EW
93
92
91
42
DW154 Specificatiol for Plastics Ductwork
STANDARD OMPONENT DRAWINGS - CIRCULAR
FIG
94
DRAW G
I
~ 30deg 090deg
Breeches Piece
DETAILS
95 amp-----~ Blank End
~-----p Multi-Leaf Damper Can be piggolcd or fianged opposed or parallel blade
Alternative controls areshyri=-+- L-T~
I
---
LT~
I r- -
-+1
J HO Hand96
bMD Molori cd
PD Pneumatic
tl-shy bull
Single Bladed Damper 97 ~ saD
on-Return Damper Vertical application only 98 m~D
43
DW154 Sf1tcificatioll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG
99
100
101
102
DRAWING
$ I-
2hr
1 4hr
SD
~v I I
CO TINENTAL COWL
DETAILS
Iris Damper
Fi reS moke Dam persSleeves
2hr Ratillg
With installation frame
4br Rating
Smoke damper
Intumescent Sleeve
Access Openings
Access panel - removable
Access door shy hinged
fnspection cover
Discharge Continental Cowl
44
DW154 Sp(Cii(ltJll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
DRAWINGltIC DETAns
-
I
I
~
I I I High Velocity Discharge Terminal 103 I
I
I I
J I I 1 ~--
Offset Stack Discbarge Terminal 104 1
~ I e --(-
I
N
I
I
I~
I I Vertical Oischarge with Weather Cowl 105 I
--1--1 I
I
GAPI I
RTl AL DISC) lARGE WITH W ATIIER COWL
45
DW154 SpecUicatoll for Plastics Ductwork
STANDARD COMPONE T DRAWINGS - PLA TEQUIPMENTIMISCELLANEOU
FIG DRAWING DETAILS
106 ~~~ Rectangular Attenuator
107 ~- Circular Attenuator
108
~ Beod Attenuator
109 J ~(f) Heating Coil
110 J ftte Cooling Coil
III Jc[ Electric Heating Coil
112 X F
Humidifier
113 [H XX Axial Fan
114 ~fB1famp Noo-standard Ductwork Cross hntchillg (of any separate type) indicates by reference to a key any non DVil54 ductwork system
115 2llIIIIJIIIIIll Flexible Ductwork
46
DW154 SJeCUicll(iol1 for Plastics Ductwork
TABLE 12 - STANDARD ABBREVIAT ONS
ABBREVIATION FLL
AD Acces Door
AFF Axial Flow Fan
AHU Air Handling nit
All Aluminium
AP Acess Panel
AT Attenuator
AV Air enninal Unit
BE 81ank nd
BQ Blast ate Damper
CC Cooling Coil
CF Centrifugal Fan
CTA Cross alk Attenuator
CVU Constant Volume Unit
DP Drain Point
EEC Electric Heating Coil
El Expansion Joint
FAl Fresh Air Inlet
FA From Above
FB From Belo
fBPP Fabric Backed Polypropyl-ne Sheet
Flexle Flexible Connection
lexfD Flexible Du t
C False Ceiling CO an oil Unit
fD Fire Damper
FFL Finished Floor Level
FJ Flanged Joint
FOAM Rigid Polyurethane Self xtinguishing Foam
FOB Flat on Bottom
FOT Flat on Top
GAM Galvanised after ManufacttrJc
GRP Glass Reinforced Plastic
GSS Galvanised Sheet Steel
HC Heating oil
HD and controlled Damper
HH Hand Hole
HL High Level
HVD High Velocity Discharge
IC Inspection Cover
ID lri Damper
IFS Intumescent Fircleevc
47
DW154 Specification for Plastics Ductwork
TABLE 12 - STANDAR ABBREVIATION CONTINUED
ABBREVIATION
IU
L
tv1D
MS
NRD NTS
OBO
OE
PHD
PD
PP
PP
PRD
PVC
RFC
RSC
R
SBO
SO
S1 TST
SSL
TA
TB
TO TJ
TP
TV
TV
OS
UPVC
S
V
VAV
50 RSA
FULL
Induction Unit
Low Level
Motor controlled Damper
Mjld Steel
on Return Damper
at to cale
Opposed Blade Damper
Open End
Parallel Blade Damper
Pneumatic controlled Damper
Polypropylene
Self xtinguishing Polypropylene
Pressure Relief Damper
Polyvinyl Chloride
Rolled Form Chamlel
Rolled Steel Channel
R fUnit
Singl Blade Damper
Smoke Damper
Slip Joint
Stainl t el
tructural Slab Level
To Ab vc
To Blow
Top Down (In Direction of Flow)
Telescopic Joint
Test Point
TU111iog Vane
Top Up (In Direction of Flo )
Voles Otherwise Stated
Unpl3sticisecl Polyvinyl Chloride
Underside
Ultra Violet Light
Variable Air Volume
Rolled Steel Angle (Vith Size)
48
DW154 SJeriiflllioll for Plastics Ductwork
A2 DUCT PRESSUREAPPE DXA Ductwork con truct d to DWIl54 will bebullbullbullbullbullbullbullbullbullbullbullbullbullbull
Air Leakage From Ductwork To be read in conjunction with DW143 A practical guide to Ductwork Leakage Testing
CAUTION As highlighted ill both this docul1lenr and DW14 I lot ellough emphasis can be placed 01 the fact that except for high pressure class C the much more stringent ductwork constructional standard brolght about b the general acceptance of DW154 have irtlally negated the requirement for leakage-testing It is essential lO realise lhat except where it is mandatory this doclllllelll is nOl an endors ~lIlent of the rourine testing of ducts bllt purely a guide to outline the procedures for cononnity with the air leakage limits ill Table l Where the specified methods of assembly and
A3sealing of dlcls are u ed a vi ual inspection wil ordinarily sl~fll e for ver(iatioll of a well engineered and a ceptahfy airtight COl1strucrioll WHERE NOT MANDATORY DUCT LEAKAGE TESTING IS GENERALLY AN UNJUSTIFIED AND SUBSTANTIAL EXPENSE
A1 INTRODUCTION L akage from ducted air distribution systems is an Lmportant consideration in the design and operation of ventilatjon and air conditioning middotystems A ductviork t)ystem tbat ba limited air leakag within defiucd limits wiH cnsUft
that tile design characteristics of the sytem can be maintained It wilJ also ensure that energy and operatLonal cosb are maintained at optimum levels DucLwork constlucted and Ulstalled in accordance with DW154 should minimise a level of air leakage that it) appropriate to tll operating static air pre sur in tile system
A4However it is recouuised that tbe environment in wtJich middotystems are installed is not always conducive to achieving a predictable level of quality in term of system ajr leakage and it is therefore accepted that designer may sometimes require tlle ystem to be tested in part or in total It should be ecogni ed that the testing of duct systems add a ignificant cost to the installation and incur some extra tjm within the programme (Se 47 and 64 re mandatory te-sting)
manufactured to a structural standard that is compatible with the system operating pressure There are three classes of duct con truction to eorre pond with the three pre ure clas meations Class A Lo pressure ducts suita le for a maximum positive operating pressure of 500 Pascal and a maximum negative pressure of -500 Pascals Class B IVledium pressure ductmiddot suitable for a rnaxilnuJJl positive operafjn o pressure of 1000 Pascals and a maxllnum negative pre sure of -750 Pa cal Class C High pre sure ducts suitable for a maximum po ilive operating pressur of 2000 Pa cals and a maximum negativ pres ur of -750 Paltcals
LEAKAGE FROM DUCTWORK Leakao-e front pia tic air ducts occur at the joint~ and is therefore proportional to the total surface area orthe du twork in th system Tb level of leakage i imilarly related to tIle air pres ure in th du t system and whilst there LS n precis formula for calculating the level of air los it i generally accepted that leakage will increase in proportjon to pressure to rbe pOvver of 065 The effect of air leakage from high pressure velocit ductwork is critical tn terms of system perfomlan dege energy consumption and the risk of high frequency noise as ociated with leakage These problems are le critical with medium pressure 10 ity systems but should be con idered Low pres mevelocity ducts present the lowe~t
ri k in tenn of tbe effect of leakage on the operation of the s stern
SYSTEM LEAKAGE LOSS As there i no di ct relatLonship between th volume of air conv yed and the surface area f the ductwork sy tern required to match the building configuratmn it is difficult to express air leakage a a percentage of total air volume Similarly the operating pressure will vary throughollt lh 3 system and a leakage is related to pre me the calculations ar comple However it is generally ac epted tbat in typical good quaJjty systems the leakage from
49
DW154 Specificatioll for Plastics Ductwork
each class of duct llnd r operating condition will be io the region of CIa S A low pressure 6 Clas B medium pres un 3 Clas C high pressure 2
A5 SPECIFYING AIR LEAKAGE TESTING Re peeting both the co -t and programme implications a sociated with te ling du 1 for leakage the designer may for example indicate that a particular system is te ted as follow
a) High pressure ducts - all tested b) Medium pr ssure duets - 10 of the
ductwork shall be s eet d at random and tested
c) Low pre sure - unte ed In any case where a random te t i elected for medium pre sure ductmiddot the followin c1au~e is suggested for inclusion by the de ign r
The designer hall elect at random a maxirnwlI of 10 of the dUCl system to bt tested for air leakage The duct hall be tested af the pressure recommended in Table J3 for the assifi atiol for the ectiol1 of the ductwork that is to be tested The tests shall be carried Ollt as the work proceeds and prior to the application of thermal insulation In the event of test failure of the randomlY selected section the designer shall have The right to select two La1her e tiolls at random for resting Where succes ive failures are identified there shall be a Tight to require rhl COl11raCWr 10 apply remedial attention to the complete ductwork system Th contractor shall provide documented eviden e of the calculalions used to arrive (1
the allowable 10 I for the section to be tested and the client or his agent shall willess and sign the results of the test
able 13 Air leakage rates
Maximum leakage of duct work Static
prcssUft Low-pressure edium-prc-sure I Iigh-prebull me diJfercntial Class A Class B Class C
1 2 J 4 Pa Litres per second per quare metre of surface area 100 054 018 ZOO 084 028 300 110 037 400 132 044 500 153 051 600 058 019 700 064 021 800 069 023 900 075 025
1000 080 027 1100 1200 1300 1400 1500
029 030 032 033 035
1600 1700 1800 1900 2000
036 038 039 040 042
Note Recommend d mean test presures are highlighted iD bold type with the actual selection being left to tll test operator
50
DW154 Sfeeiieaioll for Plastics Ductwork
A9
A10
and air leakage classification for the y em under test
DESIGNERS CALCULATIONS The designer can middotaJculate with reasonable accuracy the predicted total loss from a ystem by
a) Calculating the operatin presure in each ection of the sy tern
b) Calculating the surface area of the ductwork in each correspondin pre lire s ction
c) Calulating the allowabl~ los at the operating pressure for each ection of the system (see table 13 for allowable leakage figures)
VARIABLE PRESSUR S IN SYSTEMS De igner can achieve significant co t saving by matchina operating pressures throughout the system to constmctional standard and appropriate air leakage testing eO the practice of specifying construction tandards for whole duct sy tems based on fan discharge pre sure may incur unnece sary costs on a project For example ome large sy terns ould well be classiC ed for I akage limits as follows
Plant room risers CJas C Main floor distriblltJou CIa B Low pre sure outlets Cla A
A6 SPECIAL CASES There may be ~itLlations on a project where circumstance dictate thal pecial consideration be given to containing air loss s eg a long mn of duclwork may incur a di -proportjonate level of air 10 s In ca es such as thi example the designer can specify an improved tandard of airtighmess ie 80 of alJo~able 10 s for la B Ju ts The designer sbould not specif a CIa C t sI at CIa s C pressure for a CIa s B ducl
A7 SUGG S ED RANGE OF TES ING
A8 TESTING OF PLANT ITEMS Items of inline pJant (eg Fig 106 to 115) will not normaUy be included in an air I akage test The dllctwork contractor may indud such itelllS in tbe te t jf rh quipm ot has a certificate of COnfOlnlity for Ihe pres ure clas
bull High pressure duct bull Medium pre sure ducts bull Low pre sur ducts bull Exposed extract syst ID bull Ceiling void extract
systems bull Secondary ducts from
VAV or fan coil units bull Flexjble duct bull Final connections and
branches to grille and diffusers
100 test See A5 Untested UDt sted
Untested
Untested Untested
Untested
SI
i
DW154 SJecijicafion for Plastics Ductwork
ig 116 Permitted leakage at various pressures
Leakage in litres per second per square metre duct surface area
Vgt
o ltgt 0 ltgt N
ltgt Cgt
0 0 cc
0 0
~
g =
g ~
c 0
J
ltgt 0 I
~ ] tn
ltgt ltgt
In ol
~ 0 ~ 8 ~
~
c ltgt ltgt
~ CJ
~ ~ ~ ~ 8
0shyij
~ ~ ~ t
ltgt ltgt 00
l
~
~ Q
c C
~ rshy
e ltgt
I 1
I Cgt ltgtv
c Co ~
~~ ~ 10
I
0 Cgt
fJshyq 410 ) 1 ltgt
ltgt N
~ shy ltgt ltgt
~ I 1
c
52
DW154 Specificatio for Plastics Ductwork
Example of a completed test sheet Test No
General
Name of job N~ jC43Pt(r2lef Building Repound ~(~~0
Part 1 - Physical details
a Section of duct work to be tested ~(diffPIfff~el1f3rd Floor
b Drawing Number g91~~ c ssure aSSJ L atlOn V~Jl~IRfYgtg~~lPre Cl T Class C
d Test static pressure -(9 raErq~ ~~~~-~~J~~~ ~~ ~~~~ll
Leakaoe factor 9~-tre3$ecMz I OM REFTOTABLE 13)e b bullbullbullbullbullbullbull
f Surface area of duct under test Q~tJJItetre$ CPROMCALCU TIO BELOW)bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull ampampamp bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull
g ]Vlaxi mum permitted leakage -~ (~i~~0 ~~r~~ ~~~l-~-11~ ~~~Q
Part 2 - Test particulars
a Duct static pressure reading 9QFt~q~ ~ middot~~~1 ~~
b Manufacturer and type of liow measuring d vice (-~~~cJ~Y-9Q7EYg c Range of measurement of now measuring device QtP)OQ~(e~~~0I~~~~1~I~ ~~~~~~W~
d Reading of flm measurin o device pmiddot IFROM RIO)ftscag ~
I (DERlVED [ROM CHART SUPPUED WITH RIG US 0 ud)1e Interpreted air flow leakage rate ~(~~~f~~~ (~l~~~~~~~~~~~~~~~~~I
f Duration ~~~~~norn~allY l~ lnil1Ut~~d~~~ it1~ W~ Date of test ~(lITled ut by Wltll s ed by ~ ~
(~lJ MIJLrr) (Si~rrfltJUYJ
Printed Name 1~g0f~ Printed Name ~~Y~9~ and Company 7jl~~~~~( UJd CompanY AB COII$Itallt8
Width and depth or diameter
Periphery ength Area
millimetreS millimetres metre qL1are metre
800 x 750 3100 1755 5440
600 x 650 2500 557 1193
300 x 300 1200 120 144
305 din 958 700 670
250 dia 785 450 353
TOTAL 8000
53
DW154 Specijilarion for Plastics Ductwork
pA XB
Guida ce No es For he ransport Handling and
Storage of uctwork
avoid damage to adjacent duct panels In somc ca es particularly on con acts calling f r repetitive sizes the use of timber jigs and spacers may be justified Where reduced bulk and greater protection are major factor such as consignments for export transporting ductwork in L shape sections may justify the increa ed ite as embly co ts
It is recommended that before a contract is finalised that consideration is given to the subject of site acces material handling and storage as tbcy havgt a strong influence on the cost efficiency of the overall activity of ductwOlk installation
B3 Handling To minilnise th risk of damage duct sections should be clearly identified and deliveries to site should be closely linked to the installation programme so as to avoid accumulation of
B1 Storage and Handling of Ra Material Material should be stored in suitably designed racking out of direct unJight Where possible the e racks should be metal to earth Edges of cut she t may be harp and protective gloves are advised Wearing teel toe-capped boots is recommended Most pIa tic sheet is manufactured with smootb mfaces andor is suppLied with protective coating Care must be taken to prevent accidental lippag of stacked materials Beiuoshy good electrical insulators the movement of stock unless earthed will allow the build up of stati All stock shapes are chemically stable at normal temperature Whil t some raw materials used in their manufacture may themselves pre ent a toxic hazard once incorporated into the lOck bape they no long r constitute such a hazard and no dermatitic bazard are known nor are any
unfiJied ductwork and minimise double handling It is important to recognise that ductwork panels joint and corners arc susceptible to damage and care must be taken wheu band ling such material through a site During handling individual item of duct work may be liable to light cross sectional deformation until thev become an integral pan of a completed ductwork system Whilst this may temporarily detract from its intended appearance thi deformation will not have any detrimental effect on the functionality of the finally a semblecl system Installation of duct work and asociated plant items ill illevitably involve manual handUng The responsibi Iiry of employers and employees to a ses the risk of personal injury during mallual handling operations is et out in the HS E publication L23 Guidance on Manual Handling Regulations 1992
environmental problems expected 84 Site storage
B2 fransport Large capacity vehicles with high-sided open or closed-top bodies are tlle mo t suitable for the transport of dllctwork Careful consideration should be given to the
Adequate floor space IDust be provided within tbe building for the site storage of ductvork Such storage shalt make due allowance for thc stOf(ne of ductwork in stacks such that access ~ egt
between them is of sufficient width to pennil the removal of item without interference to
unloading of transport on sit a not all siJes b n fit from the material handlino- and access facilities that exi [ in a manufacturing workshop such as crane- fork-lifts or loading bay Site handJiog facilities along with
adjoining sta ks Ductvork components should be positioned so a to avoid crushing Ductwork of small panel size may be stored horizontally however care should be exercised to ensure that tack sizes are limited 10 within
ehicular acce s restrictions may itilluence the type and ize of transport to be uWised
engtlls of ductwork should be positioned 0
the tmctural strength of the duct sections to prevent distortion of the lower sections within the stack
as to avoid crushing Lengths Witll projections such as branches and bends i1anges girths damper quadrauL should be loaded so as to
54
DW154 S1tciic(ltioll for Plastics Ductwork
85 Internal cleanliness of new ductwork The site storage of ductwork introduces the important cODsideration of maintaining the internal cleanliness of the ductwork R feren e should be made to HVCA documentshybull DWffM2 Guide to Good Practice - internal
Cleanliness of New Ductwork Installations If the above conditioDs can not be satisfied consideration should be given by tJle designer to amending the specification to include for Po t Installation Cleaning as covered by tJ1C HVCA documentshybull TRJ17 Guide to Good Practic - Cleanliness
of Ventilation Systems
APPE DIXC
Fi e Retardant inishes C1 Improvement in the fire retardancy of plastic
ducts can be achieved to varying degrees and is wholly dependent llPOll the surface coating laminating resin selected and construction specification adopted In some instances smoke emission is coILSidered equaUy with other speci fication requirernen ts of the materials resistance to ignition and bumjng It is therefore important for design rs to establ ish the clients and officers detailed requirements and not rely on a tbird party interpretation of fire resisting or fire retardant Where possible the specification should refer dir etly to compliance with a British or European Standard identifying the specific sections applicable There are various types of resin and mat rcLnforcements that can achieve a Class 1 surface spread of flame ratin o when tested according to BS476 Part 7 (1987) This test puts materials illto Class I - 4 in descending order of perfoDllance according to the rat and extent of flame spread over their surfac under standard beating conditions Materials should also be tested for flre propagarion to BS476 Part 6 (1989) Tbi tesr measures the amount and rate of heat evolved by the material when subjected to standard heating
conditions Test results are given as an index of Perfonnance (i) whicb is based on three sub indices (iJ (i1) (h) The higher the value of the Index of Performance (i) the greater is the material s contribution to fire growth The higher the value of the sub-index 0) rhe greater the ease of ignition aod flame spread The highest product performance classification as defined in Approved Document B of the Building Regulations is Class O This is acLlieved if a material surface of a composite ploduct i~ either a) composed throughout of materials of
limited combustibility or b) a Class I material which has a tlre
propagation index (i) of not more than 12 and sub-index (i l ) of nor more than 6
01 J Class 0 is not a cla$sif1cation identified in any British Standard test
There are resin system reported to be classified to Class O when tested to BS476 Pcl1S 6 and 7 however designers need to ensure that such sysrems can be applied to their proposed design In propriety resinmat system available the fabrication techniques and COITect application are critical to the integrity of the reinforcing and clas ificatiol1 For example in some systems the u e of a non-fire retardant gelcont on a fire retardant substrate would reduce the classification For further information see HVCA publication DW144 Appendix D
55
DW154 SplCijiClIliol1 for Plastics Ductwork
x Guidance otes For nspectmiddoton Servicing a d
Clean-ng Access Openings
D1 GE ERAL This appendix highlight in ummary fOI111
the acce considerations that hould be made by the design r iD terms of inspection servicing and cleaning Having considered the seop and the design of the dUCI work system relative to the guidelines outlined below the designer should clearly indicate which levels of acces should be incorporated into the manufacture of a new duct work system (See Table 14 and Note I b low it
D2 DESIGN CONSIDERATIONS
D21 In ptction and servicing requireshyments are set out in Section 15 of Lhis specification
D22 Cleaning requirements are set out in the HVCA pubUcation TRl7 Guide to Good Practice Clean Lines of Ventilation Systems and the guide tates The precise location ize and
type of access would be dependent on the type of ductwork cleaning inspection and te ting metbods to b adopted Care protection and standards of cleanliness prior LO cOlllmisionin o
are set out in th AV A publication DWITM2 Guide to Good Practice Internal Cleanliness of New Ductwork Installations and th guide state Wh re specific limits of cleanliness are required ductwork sball be cleaned after installation by a spcialist cleaning contractor It will b in the interests of tht desioner botb financially and practically to cunsider employing a specialist c1eauing contractor at tbe
outset of a contract to internally clean newly installed ductwork prior to bandover This approach would reali e the following benefit shyi) Tb actual numb r of cleaning
access panels could be detennined to suit the method of cleaning to be adopted (This may be 1 s than the maximum requiremen listed under Lev 13 of Table 14)
ii) Clear directions could b given to the ductwork contractor as to tJle size and location of cleaning access panels that are required to be fitted during the mauushyfaclunng pro s
iii) The specialist cleaning operation prior to commi ioning vould enable the cleaning contractor to verify the practical acee requirement for the future cleaning operation associated -vitb a regular maintenance programme
iv) A specialist cleaning operation prior to commissioning would allow the designer to omit from the speeilicatiolJ the DWrrM2 requirem nt for factory sealing protection wipe downs and capping-off
v) Specialist Ieall ill 0 to the measurable standard defin d in TR17 will allow an objective definition of cleanline to be achieved
Car ful consideration must be gIven by the designer to the practl aJ problems associated witb the manufacture and fitting of suitably si Led access panel on small cross section duct and on the circular faces of rouod and flat oval ducts in particular
D23 Special con ideration must be given by the de igner to the practical problems associated with gaining personnel access to heavily congested ceiling areas and multi-la red du twork systems This approach would avoid
56
DW154 Spfciication for Plastics Ductwork
the possibility of access panels being D3 ACCESS 0 IN-LINE EQUIPMENT incorporated into a ductwork system at the This appendix unly covers acc il1spection manufacturing stage that were later found in through the ductwork body adjacent to an item practice to be inaccessible for either ervicing of in-line equipment and not openings in the or cleaning activities equipment itself
able 14 Acce requirements for inspection servicing and cleaning
HVCA PUBLICATIO REFE NeE (uidtgt 10 Gund Prartict
Adjace t OW144 Cleanliness orVcnlillltio S~lcr~ fRjJ7
in-line LeyeJ 1 Level 2 Level 3 ite sequipment pcdionSen lcin~ Section d C1eaniJl( SUn(O)lnspc lion Palle ltk~m_n
2011 (minimum OiL Jubje-ct to duct ~zel (ft~ -Panels
Control Da pcrs One (inspection) 203 One 300 mm x 200 mm Both sid Fire Dampers One (sCTjdJl~) 20211 One 300 0101 x 200 mm One side HeatingCooling Coils One (inspedion) 20213 One 300 mm x 200 mm (lIpstream) Both sides Attenuators (rectangular) None required One 300 mm x 200 mm (downstream) Both sides Attenuators (circular) one retluired One 300 mm x 200 mm (downstream) One side Filter Sections One (inspection) 20212 one required Uoth sides Air Turn Vanes None requjred None required Both sides Changes of Direction None required one required One side In-Duct FansDevices One (inspection) 20213 None required Both sides l
1 In the absence of any indication by the designer only Level ) access will be jncorporated into a new ductwork system
2 Tbe panel izes associated with Lev lis I and 3 acee s ar e middottablished by reference to Section 20 of DW144 and Section 2 ofTRll7 respectively
57
DW154 Speclfifatio for Plastics Ductwork
pA XE
B-bliography Included in this Bibliography are technical pUblications which may be of interest (0 ductwork designers fabricators and erectors and to tho e in the heating ventilatlng air conditioning industries generally nquiric should be made of the relevant organisation at the address quoted Since its publication other addresse contained within 0V154 mav have changed and some pubJicalions may have been superseded
HEATING AND VENTILATING CONTRACTORS ASSOCIATION
4 Palace Court London W2 4JG Telephone 020-7229 2488 Fax 020-7727 9268
Orders fo FlY A Publications Old Matlsion House Eamont Bridge Penrith Cumbria CA 10 2BX (Telephone 01768 864771 Fax 01768 86718) Email hvcapoblicationshvwelfarecouk DWn 44 pe ilicatiun for sheet mctal duclwork (Iow- mediulllshy
and high-pressure) 1998) DWIl4 A practical guide to dUGI ork I akage te ting
(revised 2000) DWII54 Specification for plastic~ duct rk DW171 Guide to good Practice for kitchen venlibtion system DW191 Guide to good pracuce glass fibre ductwoJk DwrrMI Acceptance cheme for new products - Redangolar cro
joint classification Guide to good pra tice - Internal cleanliness of new ductwork installations Guide to good practice for the design for the Installation of lire and smoke uampers
J 1Other puhlications
HampV safely guide 5th edition JS2 Tool box talks JS5 Weldlng Safety booklet JSI9 afety facts bo klet Fact sheets 1-24 2nd edition JS2J COSHH manual volume 1 Advice on compliance with the
regulations 1521A CO I-rH manual volume 2 Asses mcnt h ets JS23 Ri k management manual TR3 BrazinltT and bronze welding of copper pipework cUld sheet
(I 976) TR5 Welding of carbon steel pipework (1980)
TR6 Guide to Good Practice for Site Pre sure Testing of Pipework (19 0) Guide to good practice cleanliness of ventilation Ylem
CHARTERED IN TITUTlO OF BUILDING SERVICES E G EERS Delta House 222 Balham High Road London SW12 9BS rTelephone 020-8675 5211 Fax 020-8675 5449) CIBSE Guide Volume A Design Data Volume B In tallatiol1 and quipment Data Volume C Reference Data
CommlssioniJIg Codes These Codes eover the preliminary checkS eUing to work and regulation of vanous catcgories 0 plan The Codes give a guide to design implications Series A Air Distnbution Systems Series B Boiler Plant
ri s C Automatic Conlrol ystems Cr1es R Refrigerating Sy terns
Sene iN Water Distribution Systems
Technkal Memonllda TM 4 Design Notes for the Middle East TM bull Design otes for Ductwork TM 13 Minimi iog lhc Risk of egiounaires Disease
Research Reports RROI95 Ventilation system hygiene - A review of published
infomlatioo on lhe occurrence and ffects of Olltamination Rl~02J95 Air-to-air heal rec v ry RR0395 rnfluen e of HV C on smoke detectors
ATlONAL ENI [ERING SPECIFICATION LfMITED Southgatc hamber 3739 Southgate Street Winchester S023 9EH (Telephone 01962 842058 Fax 01962 R(8982) BUfLDING S RVICES RESEARCH AND [ ORMATION ASSOCIATIO Old Bracknell Lane West Bracknell Berkshire RG 12 4AH (Telephone Brackl1eU (01344) 426511 Fax 01344 487 -7 )
Application Guides AGln4 De tglJing Vana~le Volume middotylans for KOOnl
iir Movement AG1I91 Commissioning of V Sylcms in Buildings 11 6194 Fire Dampers
B) 94 cntiJalion or KitcneTls
AG389 The Commls ionin of Air Systems In Buildmgs AH2192 Commissioning of Bern - A ~ode of Practice TN2417 I Fire Dampec il) Ventilating Ducl
BEATING VENTILATING A AIR CONDITION G MA UFACTURERS ASSOCIATIO (HEVAC) HEVAC Henley Road Medmenham Marlow Buck SU 2ER (Telephone 01491 578674 ox 01491 575024 Emoimiddot infofetacouk)
Publicatjons Air Diffusion Guide Guide to Air Handling Unit Leakage Testing Guide to Good Practice Air Handling Unit Real Room Acoustic ~ st Procedure Specification for the ertiiicatioll ofAir Filters Method of Test for Water Rejection PerfOnTlatce of Louvrcs Subjected 1(1
Simulated Rainfall Test Procedure for Acoustic Loo cs Specification 10 Floor GrilJes - Types Performan e and Method ofTest Specification for the Determination of the Collection Efficiency of SilJ1d
Trap Louvre Domestic Mechwlical Vclltllalion Systems with Heal Recovery Fan Application Guid
~an and Ouctwork Installation Guide Guide to Fan Noise and Vibration
pecification of Requirements for JallJral Smoke and Heal Exhausl Ventilators
pecification for Powered Smoke and Heat Exhaust Ventilators
Specification of Requirements for Smoke Curtains Design Gujue of Smoke Ventilation for Single Storey Lodustrilll Building~
Including those with Mezzanine Floor and IIi Racked Storage Warehou es - Issue 3
Guidance for the Design of Smoke entilation YSlem for Covered and Undergrollnd Car Parks - lssue 1
Application of SOloke Control Equipment and Syst m Guid to Good Practice - Isue J
58
DW154 Sp(C~tiifitiol for Plastics Ductwork
BRITISH STANDARDS INSTIT TION Sales Department 101 P ntooviLle Road London NI 9ND (felephone 020-78 1 78801)
CP 413 1973 Ducts for building ervices
SS 476 Fire tes on building matenals and lruc(ure
Part 4 19 4 Non-combustibility lest or materials
Part 6 I Fire propagation lest for materials
Part 7 1993 Surface spread of tlarnJ tesls for materia
Part 20 1987 Fir resistance of elements of construction
Part 21 1987 Fire r sistlUlce of loadbeanng elements of construction
Part 22 1987 Fhe istallceofllon-loadbearing elemcllts ofconsttuclion Part 23 1987 Contribution of componcnts to the fire resistance 0 a
structure
Part 24t987 Fire resi lance of wl1lilation ductl
SS 5588 nan 919 0 Fire Precautions III thc desIgn and OOSlnJ lion of buildings
S 729 1971 Hot dip galvanized oatiugs (or irOIl aod stcel articles
BS 1449 Steel plate sheet and Irip
Pan 11991 Carbon steel plate heel and strip Part 2 1983 Stainless steel plate sheer and strip
and
B middotENJOI49-2 996 BSEN 10149- 1991)
BSEN 10131 1992
BSEN22063 Sprayed metal coarings 1994 Protection of iron and steel by aluminium and zinc against
atmospheric cOlosion Irotectiotl of iron and ste I against corro ion and oxishydation at elevared temperatures
BS 353 1981 Glossary of lerms relnting to thermal insulation
BS ISO 1479 Self-tapplngscrewsandmetallicdri c crew
B -lSO 7049
1994
B 4800 1989 Painl colour for building purposes B 4848 l0 rolled structural steel sections
Part4 1972 Equal and unequal angles BS 5422 1990 Specification for the use of therm illuating matcriulS
SS 5720 1979 ode of practice for mechanical veutilating and air C 11shy
dirionin bull in building
l3S PR 12814-1 Bend resting for plasric welds
SS PR 12814-2 Tensile testing for plastic welds
SS PR 13067 Appro altesting for plastic welds
BS PR EN I 100-] Vi ual in pection ofplaslic welds
SHEET METAL AND AIR CONDITIONING CONTR-CTORS NATIONAL ASSOCIATION INC (SMACNA) Headquarters 420 I Lafayeue Center Drive Chanlilly Virginia 2051-1209
Mailing Address pa Box 221230 Cbantilly Virginilt120 153-1230
Telephone (703) 803-2980 Fax (703) 803-3732
Accepted IJJdustry Pl3Gtice for Industrial Duct Constnlelion 197 ) i-rchitecmral Sheet kwl Manual ([993)
Comractors Guide lor Modification 10 ooslruerion Colllraets 1993 Ducted Eleclric Heat Guide for ir Handling Ssrerns (1994)
En~rgy ollservatioD Guidelines (1984) Energy Recovery Equipment yslClllS (199l
Fibrou GIns Duct onS1ntClion Standards (1992)
Fire Smoke amp Radiation Damper In tall Guide for HVA Syst ms (1992) Guide t leel Stack 1(95)
HVA Air Duct Leakage Test Manual (19 ) HVA COlllmissioning lvlanual (1994)
H A Duct Construction Standards-Metal amp Flexible (1995) Addendum 01 (Nov 1997)
HVA Duct Systems Inspection Guide (1989)
HVA ySlems-Application (1986) nVAC ByternS-DLlct D ign (1990)
HVi Systems-Testing Adjusting amp Balancing (1993)
indoor Air Quality Manual (1993) tcheu quipment Fabrication Guidelmes (1990)
Managers Guide for elding (1993)
Rectangular Industrial Duct Cons1TUction Standards (19 0) Round Industrial Duct oustmction Standards (1977)
Sei mic Restraint Manual (1991) (wl Appendix E 1993) SMACNA Ma le Index ()fTechnical Publications (1995) Tbennoplnstic Duct CPY ) Construction Manual 1994)
DEPARTME OF THE ENVIRO MENT (Publications Centre) H Stationery Oflice 5 Nine Elms Lane London SWS 5DR
MampEJ 011972 Electrical in tallat1011 in buildings ( ew Editiou)
IampE 0319 Healing hot and cold wat r steam and gas losla1lations for buildings
M amp - No4 1970 Central heating and hot and cold ~ ateT in tallations for
dwelling
M amp ENo100 1971 Mechanical ventilation for building~
ASSOCIATION FOR SPECIALIST FIRE PROTECTlO As ociation House 235 Ash Road AJdershot Hampshire GUl2 4DD
Telephone OJ25221322 Fax 0 J252 333901
lublicalioos Fire Ratcd and moke Outlet Ducrwork An Industry Guide t Design and InSlalla lioll
HEALTH AND SAFETY EXEC TIVE Rose Court 2 Southwark Bridge London SEl 9HS Telephone 020-7717 6000
TWJ THE WELD G TlTUTE Abington Hall Abington Cambridge CB16AL Telepbone 0 J223 89162
Publication DatJ Oil w~ldll1g of lhermopla lics
59
DW154 wciiwlioll for Plastics Ductwork
A -=--DIX
Factors
Specific gravity shy pp = 091 approx UPVC = 14 approx
Some miscellaneous conversion factors
To convert
Length Inches to millimetres Feet to metres
Multiply by
2540 03048
To convert
Millimetres to inches Metres to feet
vIultiply by
003937 3281
Area Square inches to square millimetres 6452 Square millimetres to square inches 000155 Square feet to square metres 00929 Square metres to square feet 10764
Volume Cubic feet to cubic metres Cubic feet to litres Gallons (UK) to litres
002832 2831 4546
Cubic metres to cubic feet Litres to cubic feet Litres to gallons (UK)
35315 00353
022
Mass Ounces to grams Pounds to kiJograms Tons to tonnes
2835 04536
1016
Grams to ounces Kilograms to pounds Tonnes to tons
003527 2205
09842
Volume flow Cubic feet per minute to cubic Cubic metres per second to cubic
metres per second 0000472 feet per minute 2119 Cubic feet per mIDute to litres Litres per second to cubic feet
per second 04719 per minute 2119
Motion Feet per minute to metres per second 000508 Metres per second to feet per minute 197
Pressure Inches water gauge to millibars 2491 Inches wateJ- gauge to pascals (Pa) 2491 I Pa = I ewton per square metre = 10-2 millibars
60
Heating and Ventilating Contractors Association Esca House 34 Palace Court London W2 4JG
Tel 020 7313 4900
e-mail contact Itvcaorguk web site wwwhvcaorguk
Fax 020 7727 9268
DW154 Spet((icatioll for Plastics Ductwork
82 Joint sealing and sealants 8226 The joint mu t be held in po ition ror at leamiddott 5
821 General minutes A jig should be The integrity of the ductwork used jf nece-ltsary to ensure depends on the successful applicatioll that no twisting force i of tbe conemiddot t jointing metbod appl ied to th joint during
the period 822 Solvent cementing
Solvent cementing a atisfactory 8227 Once made the joint method of jointing circular UPVC should not be exposed to socket anu spigot or leeve joints a undue force for eight certain solvent based cement horn shy hour Tb full strength of geneously bond the PVC surface the jOjJlt is not achieved in providing uitabl joints Solvent less than twenty-four cementing i not practicable with PP hours because of its hioh resi tanc to solvents The procedure recommended OTE SOLVENT CEMENT JOINTING by the cement manufacnJrer should METHODS ARE TOT RECOMshybe followed but the following points ME DED FOR RECTANGULAR are important DUCT SECTIONS
[N ALL CASES S ALA MATshy8221 Clearance between ocket ERlALS MUST BE APPLIED
and spigot must be STRICTLY IN ACCORDA CE minimal because of the WITH THE MANUFACTUR ~RS
lirnited gap filling propshy 11 STRUCTIO SAD OSHH ertie of the cement ASSESSMENT
8222 Inside edges of sockets and 823 Hot air welding utside edge of spigot VC and pp a be welded by
shouJd be lightly chamshy Llsing the hot ga Ifil1er rod meUlOd fered ltmd thoroughly cleaned described helow
8223 Mating urfaces should be 8231 The welding gas can be cleaned using a proprietary nitrooen or compressed air solvent cleaner to remove and shltlll b fIltered free grease and slightly etch the from suspended water oil surface vapour and particulate
matter 8224 The cement should be
applied a quickly a 8232 The filler rods shall be possible to the socket and made from material to r pigot over the full area of compatible with the matshythe mating surface are eriaJ being welded should be taken to avoid the use of excessive 8233 Butt weld joints shall be cement bevelled to an included
angle of 60deg to 90deg and 8225 The posi liolling of the joint where po sibl welds shall
mUSl be achieved immedshy be fully penetrated from iately after the cement i both ide of the work applied aJld surplus cement removed
10
DW154 Specificatiol for Plastics Ductwork
8234 The joint face and the filler rod surfaces must be clean and grease fre and preferably roughened b shyfore welding In particular any deposited filler rod that is charred mu t be scraped away before additional runs are added
8235 The numbers of runs of fi lIer rod shall be sufficient to give a thiekne s of era s section of the veld at least equal to the thiekn s of the sheet
8236 Where high frequency park testing i specified lhi shall be undertaken in accordance with tbe weldshying in tmction handbook
Note A full descriplion of welding method is given in the Welding Institut handboo entitled Data on Welding of Thennoplastic Relevant BS amp CE Standards are prEN 12814-1 amp 2 prE 13067 and prE 13100-1
824 Completion of compo ite laminate joints Following solvent ementing or hot air welding of joints campi tion of any specified external laminate shall
carried out to maintain thebe
825
integrity of the construction (S 8227)
Gaskets These can be fabricated from various materials in the form of a pre-formed roll she t or trip applied between opposing faces of fbnced ross joints It i a visable to select material r commended by th ga ket manufacturer for the pecific appucation intended
PART 3
Rectangula ucts
9 RECTANGULAR DUCT SIZES
91 This specification covers duct size up to a rnLltimum longer ide of I -00 mm Duct size with an a peet ralio greater than 4 I ar not recommended Although they offer no problems of construction they increase friclionaJ resi tance and the pos ibility of Dois
10 CONSTRUCTION
101 General Th minimum constructional requiJement r r UPVC and PPPPS un-reinforced are hown in able 2
102 Longitudinal seams Longitudinal seams should Dot be located at corners or in the underside of the duct
103 Sheet jointing seams Seams shall be joined by continuous filler rod hot air welding or by fl1sion Vi ldiug only other form of jointing are not acceptable
104 Socket and spigot joints Sock t and spigot joints shall be formed by purpoe made double cket pi ces 100 mm long and of the ame thiekne material as the duct welded into position on each standard length of duet forming 50 mm de p sockets prepared and ready for final jointing on site with filler [Od of the ame formulation used for prefabrication (See Table 2)
105 Flanged joints
1051 FJa ges Fabricated flanges shall b con tmeted u ing miniumum of 9 mm thick by 50 nun wide material of matching formulation depending on duel size as hown in Table 2 The flange hall be mounted true and square to the duct surface and w lded on both sides a 103 and Figs 3 4 Alternative con truction Illay be
11
DW154 Spedjicfltiotl for Plastics Ductwork
utilised for attacllment to plant or other equipment
1052 Drillings Drjllings shall be placed to permit clearance to tbe extel11al casing and any reinforcement of tbe ductwork for the application of fastening
1053 Fastenings For nonnaJ application bright zinc plated bolts nuts and vashers hall be Llsed in sizes and pitch centres shown in Tabl 3 Where special conditions prevail consideration of other material finishes such as stainless steel bolpounds nuts and washers may be used In all cases gasket materials as Section 825 shaLL be used
106 Expansion joints Wher the configuration of the ductwork does not provide for movement due to temperature change or where such movement is restricted by branches or attachmenL expansion joints should be specified by the designer (See Section 18 FlexibleExpansion joint connections)
It is the re ponsibilir-y of the designer to identify the positions of any necessary expansion joints hased upon design param ters for the individual systems (See Figs 23 to 25 34 amp 35)
Design ote xamples of expansion joints shown in Figs 23 to 25 are not suitable for movement exceeding 30 mm
107 StilJeners
1071 External stiffeners Shall be fitted as specified in Tables 2 amp 10 and Figs 5 amp 6
1072 I temal stiffeners The u e of internal stiffening or bracing shall be acceptable iJ deemed necesary and approved by the designer (See Fig 7)
11 FITTINGS
111 Standardisation of fiuings The terminology and descriptions of rectangular duct fittings a et out in Section 25 are recommended for adoption as standard practice to provide common terms of reference for desi crners quantity surveyor and ductwork contractors and for those using computer in ductwork design and fabrication
Bend are designated as hard or easy and the e terms as used herein have the folJowin o
meanings
Hard signifies rotation in the plane of tb longer side of the cross ection
Easy signiiies rotation in the plane of the shorter side of the cros section
An example iIlu trating these term ] given in Fig 8
Fitting are fabricated by cutting and welding sheet
112 Stiffeners Shall be as 107 and Tables 2 amp 10
113 Splitters Shall be as shown in Fig 41 and welded as 1003
114 ruing vanes Where square bends are required turning vanes as shown in Fig 9 hall be fitted
115 Branches When fitting branch ducts to a main duct care should be taken to ensure that the rigidity- of the duct panel is maintained in terms of tbe sti ffenillg criteria
116 Change shapes Where a change bape is necessary to acconUllOdate the duct and the cross- ectional area is to be maintained the slope haU not exceed 225deg 011 any side (See Figs 52 to 56) Where a change in shape includes a local reduction in duct cras - ectionaJ area the slope should not exceed ISO on any side and tbe reduction in area should not exceed 20 Where tceper angles are necessary due to ile
12
DW154 Spec([icatirJ1l for Plastics Ductwork
restucllOn splitters shall be provided Taper Transformation pieces from circular 10 square pieces reducers and transformation piec s or rectangular shall be made as long a shall be manufactured from the tbickl1 s of p sible and uJe angl ball be uot mor than material specified for the larger size ducl 225 (Fig 55)
loon Pa 1500 Pa
2 3 4 5 6 mm mm mm mm
3 socket amp spigot - - -or tlanged
as Figs 1 2 3 401 to 600 45 flanged 50 x 9 flat 1200 800
50 x 9 flat welded both sides a Fig 3 as Fig 5
601 to 1000 45 flnged 50 x 9 flat 800 600 50 x 9 flat welded both sides as Fig 3 as Fig 5
1001 to 1500 6 anged 75 x 9 flat 600 600 75 x 9 flat welded botb sides as Fig 3 as FieJ 5
or or 70 x 70 x 9 angle 50 x 50 x 5 angle
as Fig 4 welded both sides as Fig 6
N t For constructional operating temp rature limits refer to Part 2 Clause 54
Longer Pitch Bolt Size
Side max 2
mm 1m mm Up to 400 100 8 with washers 401-600 tOO 10 with washers
601middot1000 100 10 with wash rs 1001-1500 100 10 with oycrsized
washer
13
Table 2 inimum con tructional requi ments - rectangUlar nmiddotreinforce UPVC and pp
Joints Sliffeners Maximum spacinOLonger Side MillirnUlll She t between
Thickness Joint~S(iffi ners
mm Up to 400
DW154 SpedflCiltion for Plastics Ductwork
Cross joint - recta gular ducts
Fig 1 Socket and spigot joint (UPVC and PP)
Conlinuou weld joint on sile onlinuou- wcld
CT~r~T2
Fig 3 Flange joint (UPVC and PP)
ontinuou weld
Fig 2 Socket and spigot joint (UPVC only)
Fig 4 Flange joint (UPVC and PP)
S iffeners - rectangular ducts
Fig 5 Flat Fig6 Angle
Oatim wo]
Fig8 Bends - examples of hardTie rod assembly and easy
Hard
Fig7 With spacers Easy
4
DW154 Speci(uariml for Plastics Ductwork
Fig 9 Turning Vanes
HOWl G TYl AL EXAMPLE OF FOCI G
15
Ma vane length shy 615 mm
Example ofbraemg when V1IIle length exeeed max pennined Ahematively two banks of ncs fixmg the centre rail together at ] 50 mm nrrcs
U~_II---- fixed to dnct wall both CDds
bLEVATION
vane
Maximum distance between centrc oflUming vanes should [Jot exceed 60 mm pitch
DW154 SPCCijicllfiull for Plastics Ductwork
practice to provide common terms ofPA T4 reference for designers quantiry urveyor and
Circular Ducts
12 CIRCULAR DUCT SIZES Th duct sizes [n Table 4 have been selected from the ISO and C standard ranges as the 132 preferreod sizes
Table 4 Circular ducts shystandard extruded tube sizes
133 Extruded tube
ISO Standard Sizes (Nominal Diameter) 11
Wan Wall Thickness Thickness
mm mm mm mm 110 500 4022
I25160 600 50 I25200 630 60
225 25 700 60 13425250 800 63
280 900 70 315
23 23 80
355 1000
25 1250 104 400 32 1400 108 450 35
Note The above sizes are subject to normal manufactl1ring tolerances Other size may be available in varying wall Lhicknesses and subject to test and operational pressure
13 CONSTRue ION
13 General Tllis specification covers duct sizes up to a maximum diameter of 1500 mm The minimum constructional requirements for UPVC amp PPPPS un-reinforced ducts sball be as Tables 6 amp 7
ductwork contractors and tho e using computers in ductwork design and fabrication The requirements for circular duct fittings apply throughout the size ranges covered in this specification
Sheet jointing seams Seams shall be joined either by continuous fLiJer rod hot air welding or by fu ion welding Other forms of jointing are not acceptable
Socket and Sl)igot joints Socket and spigot joints shall be formed by purpose made double socket pieces 100 mm long and of the same thickness material as tJJe duct welded into position on each tandard length of duct forming 50 mm deep sockets prepared and ready for final jointing on ite with PVC adhesive andor fill r rod of the same formulation used for fabrication
Flanged joints
1341 Flanges abricated flanges shall be conshy
structed using minimum of 9 mm thick by 50 mm wide material of matching formulation depending on duct size as shown in Tables 6 amp 7 The flange shall be mounted true and square to the duct surfaces and welded OD both sides a 103 and Fig 12
1342 Drilliogs Drilling ball be placed to permit clearance to the external casing and any reinforcement of the ductwork
1343 Fastenings For normal application bright zinc plated bolts nuts and washers hall
16
For srualler diameters preformed fittings are available otberwise fitting are fabricated from segments of duct or sheet welded together
The terminology and description of circular duct tiltings as set Ollt in Section 25 are recommended for adoption as standard
be used in sizes and pitCh centres shown in Table S Wh re special conditions prevail consideration of other material finishes such as stain le steel bolt nuts and wasbers shall be u ed In all ca cs gasket materials as Seciion 825 shall be USed
DW154 Speciliwriml for Plastics Ductwork
135 Stiffeners
1351 External stiffeners Shall be fitted as specified in Tables 67amp 1 I and Fig 13
1352 Internal stiffeners The use of internal stiffening or bracing hall be acceptable if deemed neces ary and appn ved by the designer
f 36 Expansion joints Where the corrfiguration of the ductwork does not provide for movement due to temperature
Cross joints - circular ducts
change or where such movement is restricted by branches or attachments expansion joints should be fitted (See Section 18 Flexible Expansion joint connections)
It is the responsibiLity of the designer to identify the position of any necessary expansion joints based upon design parameters for the individual systems (See Figs 23 24 2534 amp 35)
Design Note Examples of expansion joints shown are not suitable for movement exceeding 30 mm
Fig 10 Socket and spigot joint (UPVC and PP)
ConLinuous weld joim on ite Ontinuous weld
crlr~l
Fig 12 Flange joint (UPVC and PP)
Continllous wcld
boil
Continuous weld or Solvelll cement
Solvelll ccmcnl joim on sile
Fig 11 Socket and spigot joint (UPVC only)
Stiffeners - circular ducts Table 5 Fastening centres shycircular duct flange jointsFig13 Flat
flat conljnlJou~ly welded Diameter Pitch Bolt Size
max
1 2 J 11
1 shy -~
mm mm mm Up to 600 100 8 with washers
601middot1000 100 10 with washers - ---I
1001middot1500 100 10 with oversized washers
1
Minimum offourfixings
17
DW154 Specifiiutiofl for Plastics Ductwork
Table 6 constructional quiremen s - circular unshy inforced U VC
Diameter Minimum Joints Stiffeners Maximum spa ~in r
Sheet between Thickness Jointsl tiffcners
1000 Pa 1500 Pa
1 2 3 4 5 6 UD mm mm mm mm
UO to 600 3 socket amp spigot as Figs 10 11
or fla ged Fig 12
601 to 1000 45 socket amp spigot 50 x 9 flat 2400 2400 as Figs 10 11 welded bo sides
or Oanged as Fig 13 as Fig 12
1001 to 1500 6 Hanged 75 x 9 flat 1200 1200 as Fig 2 welded both ides
as Fig 13
Applies 10 Tables 6 alld 7
Note 1 For constructional operating temperature limit refer to Part 2 luu 54 2 To allow for conicleration or extruded se lions or fabricated component the materia] tllicknes i hawn a nominal
Table 7 Minimu onstrucfional requirements shy circular un-reinforced PPS and
Diameter Minimum Joints Stiffcners Maximum pacio Sheet between
Thickness Join sStiffener 1000 Pa 150n Pa
I 2 3 4 6 mm m m mm
110 to 500 3 socket amp spigot as Fig 10 or flaoged as Fig 12
501 to 750 45 ocket amp spi~ot
as Fi 10 or Uanged as Fig 12
751 to 1000 6 tlanged 50 x 9 Oat UOO 12 0 as Fig 12 welded nth sides
as Fig 13 1 1 to 1250 6 flanged 75 x 9 flat 800shy 800
as Fig 12 welded both sides as Fig 13
1251to~ flangcd 75 x 9 Oat 600 600 as Fig 12 welded both sides
as Fig 13
18
DW154 Sped(icalirm for Plastics Ductwork
PARTS
Hangers an Suppo ts
14 GENERA
141 Supports are an e sentiaJ part of me ductwork system and their supply and in tallation are normally the responsibility of the ductwork contractor The principl s are a I-rvCA publication DWIl44 Part 6 Section 19 and should be read in conjunction with this document
Design Note Designers may pecify specific requirements wbich will supersede guidance given in DW144
142 Rectangular ducts abl 8 give the- minimum requirements for
hanger and supports for un-reinforced ductwork
143 Circular ducts Table 9 gives the minimum requirements for hangers and upports for uD-reinforced ductwork
144 Vertical d cts The design of supports for vertical duct is dictated by site condition and where practical duc hould be upported at 4000 mm interval or where tbey pa s through a floor (but n ver exceeding 4500 mm) see Figs 17 amp J8
145 External ducts Where ducts are external to buildings and may be ubject to wind loading support should be plac d so as to restrain ide tl1ruSt and should allow axial movement as neces ary It is the respon ibility of me de igner to calculate the effect of the particular prevailing condition and to define any special upport requirement
146 Expansion joints Support shall be designed to permit axial movement only and shall e provided on eitl1er ide of expansion joint
I 1shy
I~
mm -Jp to 400
401 to 600 601 to 1000
Table B Hangers and Supports - rectangular horizontal ducts
Hanger Bearer Drop Roll Formed Rod
Long r Side
Cbannel ~-shy ~
---shy
Maximum ~pacing
4 52 3 _ -c Fig 15 - Figs 14 15 16 amp 2J
shy
mmm mmmm 240025 x 25 x 16 40 x 20 x 15 8 240040x20x15 40x 20 x 15 10 240040 x 20 x 1~510 40 x 20 x 15
shy
I
40 x 40 x 15 40 x 40 x 15 24001001 to 1500 I 10
Table 9 Hangers and Supports - circular horizontal ducts
Longer Side Hanoer Split Clips Maximum spacing Drop Roll f-ormed and Wrap-round Rod ~hannel Hang r
2 3 4I Fig 1920 amp 22Fig I
mm mmmm mm mm 25 x 25 x 15 IIp to 355 8 40 x 3- --1-_ 2400
2400
2400 2400
70x 6
40 x 5 SOx 5
40 x 20 x 15 40 x 20 x 15 40 x 40 15
10 10 10
356 to 600 601 to 1000 1001 to 1500
19
DW154 Spccijicutioll for Plastics Ductwork
147 Protection specification Any special coatingpaint Unless otherwise stated all support shall be finishes for protection against hostile manufactured in material as specified in this environments shall be advised by the designer
SUPPORT BEARERS
~ 14 Flg16 Inverted profile
angle I ~lIed steel
channel (alternatives) Fig 15 Profile channel (alternatives)
TYPICmiddotAL VERTICAL DUCT SUPPORTS Flat bar clipStiffening frame Outline ofinsulation stiffening frame or tlanged joint (if applicable) or flanged joint
Stiffening framc or flanged Joint
~~-I ( ee notes 10) I
r--~ -++- ~--4==J===4~---
Fig 17 Vertical rectangular ducts Fig18 Vertical circular ducts
The support bearer which depending on ducti tructural opening size could be either channel or angle section may be ll1ilised in any of the following arrangementsshy
a) To support the underside of a flat bar clip in halves (circular)
b) To support the underidc of either the stiffening frame oftbe flanged joint ofaoy duct section
c) To support either a stiffening frame Or a flanged joint below nsing drop rod srudding
20
DW154 Spediraiml for Plastics Ductwork
Arrangement of bearers and hangers (to be read in conjunction with Table 8 amp 9
wbich list material sizes relative 10 duel izes)
KEY Limits refer to actual duct size - insulation is additional - Typical
attachmentv -Atta hment t strucUlrcI to strucUlrc
I I
I - Flat Bar
I - Drop rod or - utlinc of lllddmg In ulillwn (if
applicable)
Alternative 7 drop rod or rt------------ 1 studdmg q I
I I Rectangular
ii i n 1
Fig 21 Rolled or profiled bearer Limit oncFig 19 Wrap-round hanger Limit 55 DIA
V v Drop rod orAllernaUC 1 1 tudding
drop rod or 1
-- -- 1studding and elded bas 1
I I0 -_
Limit 355 DIA Frg 22 Split clips Limit 1500 DIAFig 20 Flat strap hanger amp split clips
21
DW154 Specification for Plastics Ductwork
6PA deElned in J62 appropriate to the airflow pressure acoustic temperature and corrosion
General
15 ACCESSl SPECTION OPENINGS
151 General These are for inspectionservici ng on 1y
HVCA publication DWIl44 Part 7 - General Section 20 sets out the requirements for access applicable to this specification
152 Cleaningmaintenance Designers shall take specialist advice and then stipulate their requirements for the periodic internal cleaningmaintenance of ductwork and of the consequent need for adequate access for specialist cleaning equipment including the size type and locationfrequency of the actual access openings required
Appendix D sets out guidance notes for the consideration of cleaning access and also makes reference to the HVCA publication TR 17 Guide to Good Practice Cleanliness of Ventilation Systems which covers the su~ject
in greater detail
Note A majority of in tallations in which plastic ductwork is used are considered to have a nigb operational risk potential and provision of access should address this
16 REGULATI G DAMPERS
161 General Balancing dampers and control dampers are elements inserted into an air di tribution system or element of an air distribution sy middottem Balancng dampers permit modification of the air resistance of tbe system and consequently cbanging of the airflow rate Control dampers control tlle airflow rate and may in addition provide low leakage closure of the airflow
The deigner shall specify damper locations taking into consideration that good design practice requires a minimum of five times the diameter or width of the shortest side of uninterrupted flow between plant connections and the damper and select the damper type as
characteristics
1611 Balancing damper To achieve the required distribution of air in the ductwork system at inlets andor outlets for [hi purpose the damper blades are set and Jocked manually in position between fully open and fully closed
1612 Control damper To secure dynamic control of the air now in the ductwork system In thi function the damper will always be power actuated and may require to be modulated between fully open and fully closed and to be capable of taking up any position between these extremes In the fully open position the damper should have a minimum pressure drop In the fully closed position it will not necessarily achieve a complete shut off
162 Types of airflow control dampers Airflow dampers of various types are available for specific purposes as follows
1621 Single - blade dampers Single-blade dampers shall consist of a si ngle pi voted blade cOlllained withjn a casing or section of ductwork The blade shall be adjustable tbmugh a nominal 90 angle by means of a quadrant or similar operating mechanism Where automatic control of the damper is required the spindle shall be extended to enable a powered actllator to be mounted
Single-blade dampers shall have a maximum duct width of 400 nUll and a maximum duct height of 400 mm for rectangular ducts and for circular ducts a maximum diameter of 400 mm
1622 Multi-blade dampers Multi-blade dampers shall consist of a number of pivoted blades contained within a casing The blades shall be
22
DW154 Sedicalirm for Plastics Ductwork
adju table through a nominal 90deg angle simultaneously by intershyconnected linkage or gears connected to a quadrant or similar operating mecbanism Where automatic control of a damper is required a spindle shall be extended to enable a powered achlator to be mounted
There is no restriction on the size of duct in which multi-blade dampers or damper assemblie may be u ed Where dampers are required for blade lengths in excess of 750 mm the blades should be suitably reinforced or supponed 0
individual damper blade should exceed 200 mm in width
1623 Iris dampers Lris dampers shall consist of a nUlllber of radialty interconnected blades which open or close within a casing with duct COlll1cctions The blade shall be simultaneously adjusted by a quadrant or similar operating mechanism
Iris dampers shall be installed as specified by the manufacturers operating and installation instructions where the product is unidirectional with regard to airflow
lris dampers are available for circular ducts only in diameters up to 250 mm (it should be noted that the damper casin i appro)(imately twice the diameter of the duct)
1624 Backdraught dampers Air pressure operated uni-directional rectangular (single or multi-blade) with adapters if fitted to circular ducts
1625 Slide and blast gate dampers A damper [lsed as a shut off facility with an externaJ Lide bousing allowing the blade configuration to be fuJly inserted to fully extended for maxiDlUlll air flow
163 Construction
1631 Materials All products shall be protected against cOHosion as necessary and supplied in a fully finished condition as specified by the designer
1632 Dampers used in low and medium pressure systems The following recommendations apply to dampers forming an integral part of ducrwork with pressure classifications A and B air leakage limits
The dampers shaH be constructed to minimise distortion and prevent jammin in operation Th blade shall be sufficiently rigid to minimise movement when in the locked pOSitiOLl
The blades shall be securely fixed to the operating mechanism All balancing dampers shall have a locking device located on the outsid of the case and shall giv clear indication of the actlwl blad position All penetrations of the duct shall be fitted with suitable seals where necessary
1633 Dampers used in high pressure systems Regulatino- dampers used in duc[work sy tems to pressure cJassification C shall meet tbe construction requireshyments specified in 1631 and 1632 with operating mechanisms out of the air-stream
1634 Proprietary types of damper The use of any specific type of proprietary damper shall be confirmed by the designer In all cases proprietary dampers shall meet the relevant requirements of thi specification
1635 Damper casings Duct damper casings hall be constructed to meet th mllllmum
23
DW154 SpeciJimlioll for Plastics Ductwork
leakage Iim its sp cified for th c1uctwork ystem to which tbey are installed
In order to apply the square metre leakage calculatio as detailed in DW143 A Practical Guide to Ductwork Leakage Testing the reference casing area ball be taken as the perimeter ize of lh damper IDultipli d by the equi alent length of Imetr eg an 800 mm x 400 mm duct damper hall have a surface area for casillg leakag p donnan calculated as follow (2 x 08) + (2 x 04 x I
=24m2 casing area
Other pelforlllance ancl rating test methods for damp f and valves are specified in ISO 5129 and BSIE 1751 and are referenced belm a) Leakage past a closed damper
alve BSIE 1751 b) low ratepre sure requirement
characteri t cs BSIE 1751 c) Operational torque le ring
BSEN 1751 cl) Thermal transfer testing
BSIEN 17 I e) Reg nerated sound power levels
ISO 5129
164 Installation Dampers shall be imaalled in accordance will) any re Ievant ISO EN or British Standard 10 aJ bUT lcling regulation and national code of practice as well as the manufacturers recommendations
17 FIRE DAMPERS AND INT MESCENT SLEEVES
171 General Damper or sleeves arc requiTed on duct y~telll where the designer has -tjpulated the
duct wiU penetrate a fire compartment in the majority of application tbermopla ti ductwork is ugtecl where contamlDated corro ive or otherwise exceptional fumes are concerned it is preferable to use tire damp r which are externalJy mounted ie of the intmnescent operated crush typ
24
72 Fit-e rating The damper assembly should have a fUT
resi tance ratin o equal to that of the fir ban-jer it penetrate and ball be fire tested and rated to the timetemperature curv of B 476 Part 20 and 22
173 Intumescent sleeve At the time of writing this specification qualified test results were available for rectangular dampers and circular dampers up to 55 mm diamet r Manufacture have indicated that they are able t provide speci fications for other size and diameters This infonnation should be confirmed b th de igner Various type are available includino
tho e incorporating ruechanical closing plate and those operated anI by expanded iJllUme c nt media
In all ca es fire damp rs and intnmeBcen leeves shall be supplied and in taUed in
accordance with the manufacturer iJlStructioos and COSHH a essm nt
174 Other types Fire dampers of mious types are availabl for specific purpose~ ee HVCA publication DW144 The de igner should )lot (hat materials for con lt1Jction bould be uitablc for the par1icular application
ALL C SES FIRE DAMPERS AND fNT MESCENT SL _VES SHALL HE S PPLTED AND INSTALLED IN A ORDA CE WITH Tf--IE MANUshyPACTURERS STRUCTTONS AND COSHH ASSESSMENT
18 FLEXIBLEEXPANSION dOINT CONNECTIONS
181 General ploperties Tbe material u ed for flexibleexpan ion iojnt~
mu t meet the design r requirements for temperature air pressllrelfe resistance applicable to pl astic duct sy tem vibration and noi e br akout when incorporated into a jointconnection and shall comply ith lh standard of air-tigbtne specifi cl for the duct work sy tem of which it fOlms part (See Figs 23 24 5 26 27 amp 28 for typical con truclion clelai Is
DW154 SJecilimtol for Plastics Ductwork
Expansion joints
Fig23 Moulded bellows type (rectangular and circular)
Fig24
~F aiblc sleeve
__ liding sleeve
~~~~
Sleeve type (circufar)
Fig 25
AIRFLO
COnlinuou~
weld~
Flexible Iceve
PV A HOWN pp SE BACKING FLATS AS FIG 2
Sliding lee c Co1linuou
weld
Flanged sleeve (rectangular and circular)
25
DW154 Specificatiol for Plastics Ductwork
Flexible con ections
Fig 26 Flexible sleeve with clips (UPVC and PP)
--__ Flexible I eve
I
I
I CODn clioD to plant ~
Band clip
Fig27 Welded flexible sleeve (UPVC only)
Plastic)sed PVC slceve ~-- onll11uo1sly welded
onrreclion to planl ~
Fig28 Flanged flexible connection (UPVC and P )
t sp dally moulded flexible flanged connCClitlll
boil
C)nneclion to plant ~
26
DW154 Specificotiol for Plastics Ductwork
182 LOClt1tion Flexible joint are typicltllly lIsed at building expansion joint and fan inletsoutlets Any others required should be indicated on the de ign drawings Care should be taken to maintain alignment across jointsconnections
183 Length Flexible Jomts shall be kept as short as pra middottieable above a minimum eft ctive length of SO mm In no ca e shall a flexible joint exceed 250 mm in lengtb
184 Connections to rectang a ducts With flanged rectangular connections Ule tlexible material shall be held in pLace with flat pIa tic strip of not less U1an 6 mm thick ltlttached to the flanges using uitabJe fixings The more heavy weight type of fleAible mateLial may also be obtained formed into a channel ection with corners fitted to give a neat air tight j int For pigot connections the Be ible material shall b held in place with flat pIa tic trips n t less than 6 mm thick
t 85 Connections to circular ducts With tlanged circular connections the flexibl material shall be held in place with flat plastic backing strips or proprietary clip bands with screw or toggle fast ners
186 Welded flexible connections (Rectangular and Circular) Where the parent and llexibl material are from imilar ba ed products they can be joined to the duct u ing the welding method described in Section 823
19 PROTECT VE FINISHES
191 nles otherwise stated all ductwork shall be mallllfactured in mat fial as pecified in tbis specification Any special coatingpaint fmishes to be provid d by the duct work contractor sball be advisd by th de igner
20 CONNECTIONS TO BUILDING OPENINGS
201 Fanning and finishing building op nings are not the repoJlsibjlity of the duftw( rk contractor and the note that follow are for guidance purpo e only
2011 Openings in brick block or concrete walls shall have inset frames to provide a suitable means of fixing grille louver masking flanges or the tlanged ends of ductwork The illset frames shall be conslnlcted to maintain the structural int grity of the wlll and where applicable cavities shall be suitably lined
2012 Openin s in dry linino partItIons shall have inset frames a 2011
2013 Openjngs in cladding walls and roofs shall have flaoged leevesframes to provide a suitable means of fixing a 2011
2014 Horizontal and vertical opening xposed to oLltside atmo phere hall
be provided with a suitable weathering fini h at the external face especially where profiled cladding is used
2015 Timber framed op nings are not permitted In fj re compart ment barriers
202 Ductwork connections to building openings hall have a flange of suitable profile to permit practical fixing to the openillg frame In selecting the profile consideration shall be given to Tabl~s 2 and 10 in this specitication relating to duct ize and rating Gasket strip or sealant shall be ltlpplied between the tJaoge and building op ning frame
21 DISCHARGEEXHAUST TERMINAL
21 Tbese shall be vertical open ended and designed to meet and comply with current r gularions on contaminated flue The designer hall ensure that the de ign and perf rmance i suitable for its intended purpose Examples of some typical terminal designs are SbOiD in Figbull 102 10 bull 104 amp 105
27
DW154 SpedjimioTl for Plastics Ductwork
22 THERMAL INSULATION
221 The provision and application of thermal insulation to ductwork is not the responsibility of the ductwork contractor
222 Where ductwork is required to be preshyinsulated the specification should be agreed with tbe designer
223 Where the temperature of the air within the duct promotes condensation on the exterior surface of the duct and cause moisture penetration througb the thermal insulation vapour scaling may be required and in this case the most important requirement is to limit penetration of the seal
The extent of any vapour sealing of ductwork thermal insulation and the support method to be u ed must be clearly pecitled in advance by the designer
224 For detailed information on the thermal insulation of ductwork reference should be made to BS 5422 1990 which covers the specification for thermal insulation materials on pipes ductwork and equipment (in the temperature range -40degC to +700degC) and BS 5970 1992 which is a Code of Practic for Thermal Insulation of Pipework and Equipment (in the temperature range -lOOdegC to +870degC)
23 FIRE RETARDANT FINISHES ON PLAST C DUCTWORK
231 The designer should note tbat ductwork constructed to DW154 has no teted fire rating or information see Appendix C
24 REINFORCEMENT OF DUCTS WITH GRP LAMINATE
241 General Where ductwork is required in larg T izes than are covered by Tables 2 4 6 amp 7 or with the increased strength sometimes necessary for industrial use external reinforcement is normally pwvided by applicatioD of glass fibreresin laminate
GRP systems will bond satisfactorily with standard UPVC sheet but for pp it is
nece sary to use a specially prepared sheet with a glass fabric backing incorporated dOling manufactllfe
The detailed techniques of fabrication using GRP are outside the scope of this speci lcation but the following notes are offered for guidance of ductwork fabricators
242 Materials
2421 Quality The laminate is made up of polyester resin complying with BS 3532 and glass fibre complying with BS 3496 or BS 3749 The nominal ratio of resin to glass fibre should be 7030 by weight
2422 Minimum properties The laminate shall comply with the followiog mini mum pbysical properties
Tensile strength - 70 MNm Tensile modulus - 7 Gl m Flexural strength - 140 M Im Bond strength (hetween laminate and substrate Not less than 7MNm Bmcol hardnes Not le s than manufacturers specification
The GRP reinforcement educe the expansion of the parent material but the resultant stre ses arc well within rhe strength of the bond However the Iinear thermal expansion curve shown in Figs 34 amp 35 will serve as a guide
Surface resistivity electrkal propcltles and acoustical propertie are similar to the relevanl unreinforced materials The fire retarding properties of GRP may be improved by the use of specialisl laminating resin
2423 Forms available GRP Laminate should be built up from the separate materials ie resin aod glass fibre in the form of chopped
I strand mat or spray ravings
28
DW154 Spcification for Plastics Ductwork
2424 Workshop conditions Polyester resuls are sensItIve to lmperature and the workshop hould b maintained at a temperature of herween 20deg and 25degC HiOh relative humidities and damp onditions should be avoided A good rate of air change must be pro icled pJeferably by m chanical ventilation
2425 Storage of materials Resin and urin o agents shouJd be stored in dark cool condirions away from the working area and in confonnit with statutor requireshyments for tJle middottorage of flarmnable liquid Because of Ule Limited torage lif of the unmixed resin and curing a eot mal lials ~hould be ch eked before use to enLlfe that they are within the manufacturer pe ified sh If life (usually ix month from the dm of manufacrure)
Glass fi re should be stored separately und r clean dry conditions
243 Surface preparafon
2431 UPVC To achieve the specified bond strengtll the urface to which the GRP is applied mut first be thoroughly cleaned and then etched either by mechanical means or by the use of a suitable solvent
2432 pp with glass fabric backing To achieve the specified bond middottrength the fabric backing must be thoroughly impregnated Witll resin
244 Mixing the materials for use The re in 1 a three part mix compri lng base I sin hardener and accelerator The manufactur rs pecj[ied proportions are critical and th llUxmg sequenc pecified must be meticulously foUowed
The resin has a very limited life after mixing and before u e It is dependent on the characteri tics and bulk of th resin the alllount of hardener the degree and method of acceleration and the workshop onditions
245 Methods of application
2451 General The mixed resin may be applied by hand or b pray c1epoition The operation must b completed within the gel time of th y tern and tbe laminat fully cOI1olidated to achi v the phy ieal properties pecified
2452 Hand lay-up The duct surface i coated by hand with resin Llsing a brush and a mar of gla fibp orked in until full consolidation achieved Th proc is repeated untiJ th requird thicknes i obtained
2453 Spray depo Won The duct surface is coated WiUl re in by spray gun with the chopped glass roving added through a separate nozzle The full thickne i obtain d in layer with con olidation of each layer by hand roller
246 Construction
2461 General M ini mum COllst ructional requireshyments are pe itied ill Tabl 10 for rectangular and Table 1J for circular dUClS
2462 Joints and stiffeners Fig 29 30 31 32 amp 33 hoI TOSS
joint and tiffener for reinforced UPVC and PBPP duct
247 Worki g practices The fabrication of ductwork pecifiecl ill thi document i not affected by the addition of GRP
29
DW154 SfJcdJicatiOt for Plastics Ductwork
Table 10 Minimum constructional requirements shy
Longer Side Minimum Sheet Thicknes and
GRP Reinforcement
UPVC FBIPP 1 2 3
mm mm mm Up to 1000 3 plus 3 plus
06 kgm2 06 kgOIl GRP GRP
1001 to 2250 45 plus 3 plus 06 kgm 12 kgm
GRP GRP
2251 to 3000 45 plus 6 plus 12 kgm 12 kgm
GRP GRP
Cross Joints
UPVCFBPP 4
mm socket amp spigot
as Fig 30 or flanged as Fig 29
75 x 9 flange welded on both sides as Fig 29
75 x 9 tlange welded on both sides as Fig 29
rectangular GRP reinforced ducts
SlifTeners Maximum Spacing Between
JointsSljffeners UPVCIFBIPP UPVCFBPP
5 6 mm mm
75 x 9 flat 800 as Fig 31 or
50 x 50 x 5 plastic or MS inverted angle as Fig 32
or tormer as Fig 33
75 x 9 flat 600 as Fig 31 or
50 x 50 x 5 plastic or MS inverted angle as Fig 32
or former as Fig 33
75 x 9 flat 600+shyas Fig 31 or 50 x 50 x 5 plastic
or MS inverted angle as Fig 32
or former as Fig 33
Note 1 On rectangular duct up to 400 mm longer side no stiffeners are required 2 Applies to Tables 10 amp I I For COlJstructional operating temperature limits refer to Part 2 clause 5A 3 Tables 10 amp II apply to all pres ure classes up lo ]500 Pa
Table 11
Diameter
1 III
lJp to 1000
1001 to 1750
1751 to 2500
Minimum Sheet Thickness and
GRP Reinforcement
UPVC FBPP 2 3
mm mm 3 plus 3 plus
06 kgm 06 kgm GRP GRP
45 plus 3 plus 06 kgm2 18 kgm
GRP GRP
6 plus 6 plus 12 kglm2 18 kgm1
GRP GRP
Cross Joints
UPVCFBPP 4 III
socket amp spigot as Fig 30 or flaoged as Fig 29
75 x 9 flange welded on both sides as Fig 29
75 x 9 flange welded 00
both sides as Fi 29
inforced ducts
Maximum Spacing Between
JointsStiffeners UPVCIFBPP
6 mm 2400
800
600
Stiffencrs
UPVCFBPP 5
mm 50 x 9 flat as Fig 31
75 x 9 flat as Fig 31 or former as Fig 33 75 x 9 tlat as Fig 31 or t()rmer as Fi 33
ote On extruded tube tip to 600mm diameter no stiffenergt are required
30
DW154 Specificatioll for Plastics Ductwork
G - Cross joints and tiffeners
Fig 29 Flange Joint Fig32 Stiffener shy inverted angle
M artiPfCuQkbdd erttpObri) Wl111 RP tlddtlt
_- GRPloliu] lh~
Fig 30 Socket and spigot joint Fig33 Stiffener shy use of former
Fig 31 Stiffener Flat
I Pv FlPP ~ ~lmJaDUA1) d
OMrlQ rrnall 1( tQlS
25 STANDARD COMPONENT DRAWINGS AND ABBREVIATIONS
251 The illustrations in this section not only highlight where applicable geometric limjtations for the de ign and manufacture or ductwork components but also recommend
standard drawing representation terminology and abbreviations for both duetwork components and some of the more commonly used ancillaryplant items
252 Designers and surveyors should note that bills of quantities should provide a full description
3)
---
v
DW154 Spcc(fim(ml for Plastics Ductwork
Fig 34 Linear Thermal Expansion
u c 0 N ro 0)
b 0)
S
sect0
5 oS cl) 0)
~
on ~ ltl
c U
-30 -20 -10 0 10 20 30 40 50 60 70 80 90 TEMPRATURE C
~ V
-
~~c_ ~
~V
V ~
-7 ~
-- ~V ----
v
-6
+14
+12
+10
+8
+6
+4
+2
0
-2
--4
ig 35 Typical Design Stress tor UPVC and P
7
6
r shy 5E
-c E----0 4t) VJ 0)
ci5 0Jl 3
~
0)
Cl
2
1
o
UPVC
1
000
1
1
pp
- r-- shy r----- shy - t--shy I
__0
-30 -20 -10 0 10 20 30 40 50 60 70 80 90 TEMPERATURE C C
Note Figso 14 amp 35 shaded area refers to GRP reinforced duct
32
DW154 Speciicfltirm for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - REC ~NGULAR
Splilt~r Posilion W-mm pliucr
A B c 40]--QOO 1 W - -
601-1000 1 W4 Wf2 -
1001-1800 3 WI W3 W2
FIG DRAWING DETAfiS
tU]36 ATI Straight Duct with socket and spigol joint
rn [037 Straight Duct with flanged joints
[I []38 Straight Duct with flanged joints
rkJ Short Radius Bend
39 Applies to any augl and for duct up to 400 n11n wide
Minimum (I1m31 radills = 100 mm
Medium Radius Bend (a illustrated)
[kJ Applies to any angle
40 Long Radiu Bend Similar but radius = W
Throlll radius = W2 Applies to any angle
- Short Radius Bend with plitlers
I -shy -shy u co - t lt Li--_ 41 t 0 ~ I I I
~ I
L 1W
Minimum waal radius = 100 mm Splitters not required in bend angle less than 45deg
42 QJ1 Square Bend with turning vanes ij
3
DW154 SP(L~ficatioll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - RECTANGULAR
FIG DRAWl G DETADS
43
~
I v
L L Radius Tee with internal deflectors
44
~ Radiussed Twin Bend
45
Imiddot
er Swept Branch
46 U-
Sqoare Tee with Turning Vanes
47
~ f
Breeches Piece
48 0 y l Piece
34
DW154 Specificatioll for Plastics Ductwork
STANDARD COMPONENT RAWINGS - ECTANGULAR
55
54
51
50
53
52
49
FIG
~MX
RAWlNG
DmiddotMAX
EfjMAX
Minimum throat rndius = 100 mm
Rectangular shy Round Transformatioll
Eccentric Taper 225deg max in either plane Spliller are required for angles greater than 225deg and hould bi eet the angle between any side and duct centreline
DETATLS
Angled Offset
OUset Taper Splitters are required for angle greater than 22 0
and shoold bi eet the angl between any side and dUCI centrelinc
Mitred Offset
Concentrk Taper 2250 max in ither plane SpUtters are required for angle greater than 225deg and should bisect the angle between any side and duel c ntreline
Radiussed Offset
35
DW154 Splcilcuthm for Plastics Ductwork
STANDARD COMPONENT DRAWINGS ~ RECTANGU AR
Branch ducl DimCllsions widlh (W) (A)
urnl mm up lO 200 75
300 100 400 125 600 150
Ocr 600 200
FIG DRAWlNG DETAILS
56 poundplusmni~~ Rectan~lar - Flat Oval Transformation
57 [ Square Branch
58 er Angled Branch
Branch dUCI Dimensions wfdth (W) (A)
[- mm mm59 3shy Shoe Branch Up (0 200 75
--shy AIshy + 300 100
400 125
450 MAX 600 150
Over 600 200
Branch duct DimensIOn
rP X width (W) A)
60 - 1--shy _
~ mm mm
Bell Mouth Branch pto 200 75 300 100 t 400 125
600 150 Over 600 200
0=0 61 -
~ Bell Mouth
- shy T 4-5deg M x
--I 1-shy
TJ
62 X I ] I
Tele-scopic Joint I Illustrated with flangeL
X63
SBD Single Bladed Damper
36
---
DW154 Spedicatioll for Plastics Ductwork
STANDARD OMPONENT DRAWINGS - RECTANGULAR
DRAWING DETAILSFIG
64 on-Return DamperNRD shyshy
shyXbull
Multi-Leaf Damper Can be piggoted or flanged oppo cd or parallel blade
Alternative controls areshy
q p [gtshy
J HD65 Hand
~MD otori ed
PO Pneumalic
L-lt
l 13G 66 Blast Gate DamperX X
FireSmoke DampersSleeves
211r Ratinggtshy----
L_-
---
----
r----
Ir-- shy
IL- _-l
2hr
With i tallation frame
67 41 r Rating
4hr
Smoke damper SD
Intumc cent Sleeve L-d
37
DW154 Specijicutiolt for Plastics Ductwork
FIG
68
69
70
71
STANDARD COMPONET DRAWINGS shy REC ANGULAR
DRAVING DETAILS
gtshy Access Openings
AP 6 Access Panel - Rerno able
w [ ~ Access Door - Hinged
I ~le Inspection Cover
le -I reg -lt
~X X Flexible Connection
~ Drop Cheeked Radiussed Twin Bend
U Drop Cheek Bend
I
72 Air Flow SymbolX
38
DW154 Specifim[ioll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - ECTANGULAR
FIG DRAWING DETAILS
73
74
75
76
77
Q
Q
rp---t
~
V- I Ir---I
JL --11
THE ABOVE DETAILS TYPICAL PLENUM
Air Terminal Plenums
Plenum with side connection
Plenum with top connection
Cover plate with connection
Special plenum with connection
elescopic conn ction in direction of air flow
39
DW154 SpecijicotiOll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG
78
79
80
81
DRAWING
-23~---pound3-(MALE) (FEMAJE)
-t=j--_j(--d-shy
--L
~ THROAT RADI S= D AS T NDARD
e ~
THROAT Rjf)lU = D A MU)
DETAILS
Straight Duct With male and female connectors
Straight Duct With flange joint and slip joint
Bend MouldedIFormed Applies to any angle ego 30deg45deg60deg90deg Medium radius bend as illustrated Long radius similar but throat radius 0
Segmented Bend 90deg four section minjmum as illustrated
Other Angles 60deg = 3 sections 45deg = 3 sections 30deg = 2 sections
I
i
40 shy
DW154 Speciicafinll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG DRAWING DETAlLS
82 Segmented Twin Bend Radius = D2 max
May also be fabricated from tube
83 Equal Tee MouldedIFormed
84 -~ 1in Bend MouldedIFormed
85 Taper Concentric 1 0 as iUu trated Eccentric 30deg iJJcLuded angle
86 Short Taper
41
DW154 SpcUicatol1 for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG DRAWING DETAILS
87 30 max Offset
Angle Branch
Bran h dUCI Dimcnsions dia (D) lA)
Shoe Branch mm mm 88 Cl
Off rectanguJur Up 10 200 75 lOO 10 400 125
- 00 150 Over 600 200
Bl1IllCh duct DimenlOns din (D) (A
~-$a-Conical Branch mm mm
89 Also acceptable with Up 10 200 r
full conical surface 300 10
400 125
END VrE -shy 600 150 Over 600 200
90
m 75
100 12 150 200
mm Up to 200
_ 300 400
600 Over 600
iUtred Branch
Shoe Branch
J-L----U ~ Bell oulh Branch
ENDV1EW
93
92
91
42
DW154 Specificatiol for Plastics Ductwork
STANDARD OMPONENT DRAWINGS - CIRCULAR
FIG
94
DRAW G
I
~ 30deg 090deg
Breeches Piece
DETAILS
95 amp-----~ Blank End
~-----p Multi-Leaf Damper Can be piggolcd or fianged opposed or parallel blade
Alternative controls areshyri=-+- L-T~
I
---
LT~
I r- -
-+1
J HO Hand96
bMD Molori cd
PD Pneumatic
tl-shy bull
Single Bladed Damper 97 ~ saD
on-Return Damper Vertical application only 98 m~D
43
DW154 Sf1tcificatioll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG
99
100
101
102
DRAWING
$ I-
2hr
1 4hr
SD
~v I I
CO TINENTAL COWL
DETAILS
Iris Damper
Fi reS moke Dam persSleeves
2hr Ratillg
With installation frame
4br Rating
Smoke damper
Intumescent Sleeve
Access Openings
Access panel - removable
Access door shy hinged
fnspection cover
Discharge Continental Cowl
44
DW154 Sp(Cii(ltJll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
DRAWINGltIC DETAns
-
I
I
~
I I I High Velocity Discharge Terminal 103 I
I
I I
J I I 1 ~--
Offset Stack Discbarge Terminal 104 1
~ I e --(-
I
N
I
I
I~
I I Vertical Oischarge with Weather Cowl 105 I
--1--1 I
I
GAPI I
RTl AL DISC) lARGE WITH W ATIIER COWL
45
DW154 SpecUicatoll for Plastics Ductwork
STANDARD COMPONE T DRAWINGS - PLA TEQUIPMENTIMISCELLANEOU
FIG DRAWING DETAILS
106 ~~~ Rectangular Attenuator
107 ~- Circular Attenuator
108
~ Beod Attenuator
109 J ~(f) Heating Coil
110 J ftte Cooling Coil
III Jc[ Electric Heating Coil
112 X F
Humidifier
113 [H XX Axial Fan
114 ~fB1famp Noo-standard Ductwork Cross hntchillg (of any separate type) indicates by reference to a key any non DVil54 ductwork system
115 2llIIIIJIIIIIll Flexible Ductwork
46
DW154 SJeCUicll(iol1 for Plastics Ductwork
TABLE 12 - STANDARD ABBREVIAT ONS
ABBREVIATION FLL
AD Acces Door
AFF Axial Flow Fan
AHU Air Handling nit
All Aluminium
AP Acess Panel
AT Attenuator
AV Air enninal Unit
BE 81ank nd
BQ Blast ate Damper
CC Cooling Coil
CF Centrifugal Fan
CTA Cross alk Attenuator
CVU Constant Volume Unit
DP Drain Point
EEC Electric Heating Coil
El Expansion Joint
FAl Fresh Air Inlet
FA From Above
FB From Belo
fBPP Fabric Backed Polypropyl-ne Sheet
Flexle Flexible Connection
lexfD Flexible Du t
C False Ceiling CO an oil Unit
fD Fire Damper
FFL Finished Floor Level
FJ Flanged Joint
FOAM Rigid Polyurethane Self xtinguishing Foam
FOB Flat on Bottom
FOT Flat on Top
GAM Galvanised after ManufacttrJc
GRP Glass Reinforced Plastic
GSS Galvanised Sheet Steel
HC Heating oil
HD and controlled Damper
HH Hand Hole
HL High Level
HVD High Velocity Discharge
IC Inspection Cover
ID lri Damper
IFS Intumescent Fircleevc
47
DW154 Specification for Plastics Ductwork
TABLE 12 - STANDAR ABBREVIATION CONTINUED
ABBREVIATION
IU
L
tv1D
MS
NRD NTS
OBO
OE
PHD
PD
PP
PP
PRD
PVC
RFC
RSC
R
SBO
SO
S1 TST
SSL
TA
TB
TO TJ
TP
TV
TV
OS
UPVC
S
V
VAV
50 RSA
FULL
Induction Unit
Low Level
Motor controlled Damper
Mjld Steel
on Return Damper
at to cale
Opposed Blade Damper
Open End
Parallel Blade Damper
Pneumatic controlled Damper
Polypropylene
Self xtinguishing Polypropylene
Pressure Relief Damper
Polyvinyl Chloride
Rolled Form Chamlel
Rolled Steel Channel
R fUnit
Singl Blade Damper
Smoke Damper
Slip Joint
Stainl t el
tructural Slab Level
To Ab vc
To Blow
Top Down (In Direction of Flow)
Telescopic Joint
Test Point
TU111iog Vane
Top Up (In Direction of Flo )
Voles Otherwise Stated
Unpl3sticisecl Polyvinyl Chloride
Underside
Ultra Violet Light
Variable Air Volume
Rolled Steel Angle (Vith Size)
48
DW154 SJeriiflllioll for Plastics Ductwork
A2 DUCT PRESSUREAPPE DXA Ductwork con truct d to DWIl54 will bebullbullbullbullbullbullbullbullbullbullbullbullbullbull
Air Leakage From Ductwork To be read in conjunction with DW143 A practical guide to Ductwork Leakage Testing
CAUTION As highlighted ill both this docul1lenr and DW14 I lot ellough emphasis can be placed 01 the fact that except for high pressure class C the much more stringent ductwork constructional standard brolght about b the general acceptance of DW154 have irtlally negated the requirement for leakage-testing It is essential lO realise lhat except where it is mandatory this doclllllelll is nOl an endors ~lIlent of the rourine testing of ducts bllt purely a guide to outline the procedures for cononnity with the air leakage limits ill Table l Where the specified methods of assembly and
A3sealing of dlcls are u ed a vi ual inspection wil ordinarily sl~fll e for ver(iatioll of a well engineered and a ceptahfy airtight COl1strucrioll WHERE NOT MANDATORY DUCT LEAKAGE TESTING IS GENERALLY AN UNJUSTIFIED AND SUBSTANTIAL EXPENSE
A1 INTRODUCTION L akage from ducted air distribution systems is an Lmportant consideration in the design and operation of ventilatjon and air conditioning middotystems A ductviork t)ystem tbat ba limited air leakag within defiucd limits wiH cnsUft
that tile design characteristics of the sytem can be maintained It wilJ also ensure that energy and operatLonal cosb are maintained at optimum levels DucLwork constlucted and Ulstalled in accordance with DW154 should minimise a level of air leakage that it) appropriate to tll operating static air pre sur in tile system
A4However it is recouuised that tbe environment in wtJich middotystems are installed is not always conducive to achieving a predictable level of quality in term of system ajr leakage and it is therefore accepted that designer may sometimes require tlle ystem to be tested in part or in total It should be ecogni ed that the testing of duct systems add a ignificant cost to the installation and incur some extra tjm within the programme (Se 47 and 64 re mandatory te-sting)
manufactured to a structural standard that is compatible with the system operating pressure There are three classes of duct con truction to eorre pond with the three pre ure clas meations Class A Lo pressure ducts suita le for a maximum positive operating pressure of 500 Pascal and a maximum negative pressure of -500 Pascals Class B IVledium pressure ductmiddot suitable for a rnaxilnuJJl positive operafjn o pressure of 1000 Pascals and a maxllnum negative pre sure of -750 Pa cal Class C High pre sure ducts suitable for a maximum po ilive operating pressur of 2000 Pa cals and a maximum negativ pres ur of -750 Paltcals
LEAKAGE FROM DUCTWORK Leakao-e front pia tic air ducts occur at the joint~ and is therefore proportional to the total surface area orthe du twork in th system Tb level of leakage i imilarly related to tIle air pres ure in th du t system and whilst there LS n precis formula for calculating the level of air los it i generally accepted that leakage will increase in proportjon to pressure to rbe pOvver of 065 The effect of air leakage from high pressure velocit ductwork is critical tn terms of system perfomlan dege energy consumption and the risk of high frequency noise as ociated with leakage These problems are le critical with medium pressure 10 ity systems but should be con idered Low pres mevelocity ducts present the lowe~t
ri k in tenn of tbe effect of leakage on the operation of the s stern
SYSTEM LEAKAGE LOSS As there i no di ct relatLonship between th volume of air conv yed and the surface area f the ductwork sy tern required to match the building configuratmn it is difficult to express air leakage a a percentage of total air volume Similarly the operating pressure will vary throughollt lh 3 system and a leakage is related to pre me the calculations ar comple However it is generally ac epted tbat in typical good quaJjty systems the leakage from
49
DW154 Specificatioll for Plastics Ductwork
each class of duct llnd r operating condition will be io the region of CIa S A low pressure 6 Clas B medium pres un 3 Clas C high pressure 2
A5 SPECIFYING AIR LEAKAGE TESTING Re peeting both the co -t and programme implications a sociated with te ling du 1 for leakage the designer may for example indicate that a particular system is te ted as follow
a) High pressure ducts - all tested b) Medium pr ssure duets - 10 of the
ductwork shall be s eet d at random and tested
c) Low pre sure - unte ed In any case where a random te t i elected for medium pre sure ductmiddot the followin c1au~e is suggested for inclusion by the de ign r
The designer hall elect at random a maxirnwlI of 10 of the dUCl system to bt tested for air leakage The duct hall be tested af the pressure recommended in Table J3 for the assifi atiol for the ectiol1 of the ductwork that is to be tested The tests shall be carried Ollt as the work proceeds and prior to the application of thermal insulation In the event of test failure of the randomlY selected section the designer shall have The right to select two La1her e tiolls at random for resting Where succes ive failures are identified there shall be a Tight to require rhl COl11raCWr 10 apply remedial attention to the complete ductwork system Th contractor shall provide documented eviden e of the calculalions used to arrive (1
the allowable 10 I for the section to be tested and the client or his agent shall willess and sign the results of the test
able 13 Air leakage rates
Maximum leakage of duct work Static
prcssUft Low-pressure edium-prc-sure I Iigh-prebull me diJfercntial Class A Class B Class C
1 2 J 4 Pa Litres per second per quare metre of surface area 100 054 018 ZOO 084 028 300 110 037 400 132 044 500 153 051 600 058 019 700 064 021 800 069 023 900 075 025
1000 080 027 1100 1200 1300 1400 1500
029 030 032 033 035
1600 1700 1800 1900 2000
036 038 039 040 042
Note Recommend d mean test presures are highlighted iD bold type with the actual selection being left to tll test operator
50
DW154 Sfeeiieaioll for Plastics Ductwork
A9
A10
and air leakage classification for the y em under test
DESIGNERS CALCULATIONS The designer can middotaJculate with reasonable accuracy the predicted total loss from a ystem by
a) Calculating the operatin presure in each ection of the sy tern
b) Calculating the surface area of the ductwork in each correspondin pre lire s ction
c) Calulating the allowabl~ los at the operating pressure for each ection of the system (see table 13 for allowable leakage figures)
VARIABLE PRESSUR S IN SYSTEMS De igner can achieve significant co t saving by matchina operating pressures throughout the system to constmctional standard and appropriate air leakage testing eO the practice of specifying construction tandards for whole duct sy tems based on fan discharge pre sure may incur unnece sary costs on a project For example ome large sy terns ould well be classiC ed for I akage limits as follows
Plant room risers CJas C Main floor distriblltJou CIa B Low pre sure outlets Cla A
A6 SPECIAL CASES There may be ~itLlations on a project where circumstance dictate thal pecial consideration be given to containing air loss s eg a long mn of duclwork may incur a di -proportjonate level of air 10 s In ca es such as thi example the designer can specify an improved tandard of airtighmess ie 80 of alJo~able 10 s for la B Ju ts The designer sbould not specif a CIa C t sI at CIa s C pressure for a CIa s B ducl
A7 SUGG S ED RANGE OF TES ING
A8 TESTING OF PLANT ITEMS Items of inline pJant (eg Fig 106 to 115) will not normaUy be included in an air I akage test The dllctwork contractor may indud such itelllS in tbe te t jf rh quipm ot has a certificate of COnfOlnlity for Ihe pres ure clas
bull High pressure duct bull Medium pre sure ducts bull Low pre sur ducts bull Exposed extract syst ID bull Ceiling void extract
systems bull Secondary ducts from
VAV or fan coil units bull Flexjble duct bull Final connections and
branches to grille and diffusers
100 test See A5 Untested UDt sted
Untested
Untested Untested
Untested
SI
i
DW154 SJecijicafion for Plastics Ductwork
ig 116 Permitted leakage at various pressures
Leakage in litres per second per square metre duct surface area
Vgt
o ltgt 0 ltgt N
ltgt Cgt
0 0 cc
0 0
~
g =
g ~
c 0
J
ltgt 0 I
~ ] tn
ltgt ltgt
In ol
~ 0 ~ 8 ~
~
c ltgt ltgt
~ CJ
~ ~ ~ ~ 8
0shyij
~ ~ ~ t
ltgt ltgt 00
l
~
~ Q
c C
~ rshy
e ltgt
I 1
I Cgt ltgtv
c Co ~
~~ ~ 10
I
0 Cgt
fJshyq 410 ) 1 ltgt
ltgt N
~ shy ltgt ltgt
~ I 1
c
52
DW154 Specificatio for Plastics Ductwork
Example of a completed test sheet Test No
General
Name of job N~ jC43Pt(r2lef Building Repound ~(~~0
Part 1 - Physical details
a Section of duct work to be tested ~(diffPIfff~el1f3rd Floor
b Drawing Number g91~~ c ssure aSSJ L atlOn V~Jl~IRfYgtg~~lPre Cl T Class C
d Test static pressure -(9 raErq~ ~~~~-~~J~~~ ~~ ~~~~ll
Leakaoe factor 9~-tre3$ecMz I OM REFTOTABLE 13)e b bullbullbullbullbullbullbull
f Surface area of duct under test Q~tJJItetre$ CPROMCALCU TIO BELOW)bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull ampampamp bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull
g ]Vlaxi mum permitted leakage -~ (~i~~0 ~~r~~ ~~~l-~-11~ ~~~Q
Part 2 - Test particulars
a Duct static pressure reading 9QFt~q~ ~ middot~~~1 ~~
b Manufacturer and type of liow measuring d vice (-~~~cJ~Y-9Q7EYg c Range of measurement of now measuring device QtP)OQ~(e~~~0I~~~~1~I~ ~~~~~~W~
d Reading of flm measurin o device pmiddot IFROM RIO)ftscag ~
I (DERlVED [ROM CHART SUPPUED WITH RIG US 0 ud)1e Interpreted air flow leakage rate ~(~~~f~~~ (~l~~~~~~~~~~~~~~~~~I
f Duration ~~~~~norn~allY l~ lnil1Ut~~d~~~ it1~ W~ Date of test ~(lITled ut by Wltll s ed by ~ ~
(~lJ MIJLrr) (Si~rrfltJUYJ
Printed Name 1~g0f~ Printed Name ~~Y~9~ and Company 7jl~~~~~( UJd CompanY AB COII$Itallt8
Width and depth or diameter
Periphery ength Area
millimetreS millimetres metre qL1are metre
800 x 750 3100 1755 5440
600 x 650 2500 557 1193
300 x 300 1200 120 144
305 din 958 700 670
250 dia 785 450 353
TOTAL 8000
53
DW154 Specijilarion for Plastics Ductwork
pA XB
Guida ce No es For he ransport Handling and
Storage of uctwork
avoid damage to adjacent duct panels In somc ca es particularly on con acts calling f r repetitive sizes the use of timber jigs and spacers may be justified Where reduced bulk and greater protection are major factor such as consignments for export transporting ductwork in L shape sections may justify the increa ed ite as embly co ts
It is recommended that before a contract is finalised that consideration is given to the subject of site acces material handling and storage as tbcy havgt a strong influence on the cost efficiency of the overall activity of ductwOlk installation
B3 Handling To minilnise th risk of damage duct sections should be clearly identified and deliveries to site should be closely linked to the installation programme so as to avoid accumulation of
B1 Storage and Handling of Ra Material Material should be stored in suitably designed racking out of direct unJight Where possible the e racks should be metal to earth Edges of cut she t may be harp and protective gloves are advised Wearing teel toe-capped boots is recommended Most pIa tic sheet is manufactured with smootb mfaces andor is suppLied with protective coating Care must be taken to prevent accidental lippag of stacked materials Beiuoshy good electrical insulators the movement of stock unless earthed will allow the build up of stati All stock shapes are chemically stable at normal temperature Whil t some raw materials used in their manufacture may themselves pre ent a toxic hazard once incorporated into the lOck bape they no long r constitute such a hazard and no dermatitic bazard are known nor are any
unfiJied ductwork and minimise double handling It is important to recognise that ductwork panels joint and corners arc susceptible to damage and care must be taken wheu band ling such material through a site During handling individual item of duct work may be liable to light cross sectional deformation until thev become an integral pan of a completed ductwork system Whilst this may temporarily detract from its intended appearance thi deformation will not have any detrimental effect on the functionality of the finally a semblecl system Installation of duct work and asociated plant items ill illevitably involve manual handUng The responsibi Iiry of employers and employees to a ses the risk of personal injury during mallual handling operations is et out in the HS E publication L23 Guidance on Manual Handling Regulations 1992
environmental problems expected 84 Site storage
B2 fransport Large capacity vehicles with high-sided open or closed-top bodies are tlle mo t suitable for the transport of dllctwork Careful consideration should be given to the
Adequate floor space IDust be provided within tbe building for the site storage of ductvork Such storage shalt make due allowance for thc stOf(ne of ductwork in stacks such that access ~ egt
between them is of sufficient width to pennil the removal of item without interference to
unloading of transport on sit a not all siJes b n fit from the material handlino- and access facilities that exi [ in a manufacturing workshop such as crane- fork-lifts or loading bay Site handJiog facilities along with
adjoining sta ks Ductvork components should be positioned so a to avoid crushing Ductwork of small panel size may be stored horizontally however care should be exercised to ensure that tack sizes are limited 10 within
ehicular acce s restrictions may itilluence the type and ize of transport to be uWised
engtlls of ductwork should be positioned 0
the tmctural strength of the duct sections to prevent distortion of the lower sections within the stack
as to avoid crushing Lengths Witll projections such as branches and bends i1anges girths damper quadrauL should be loaded so as to
54
DW154 S1tciic(ltioll for Plastics Ductwork
85 Internal cleanliness of new ductwork The site storage of ductwork introduces the important cODsideration of maintaining the internal cleanliness of the ductwork R feren e should be made to HVCA documentshybull DWffM2 Guide to Good Practice - internal
Cleanliness of New Ductwork Installations If the above conditioDs can not be satisfied consideration should be given by tJle designer to amending the specification to include for Po t Installation Cleaning as covered by tJ1C HVCA documentshybull TRJ17 Guide to Good Practic - Cleanliness
of Ventilation Systems
APPE DIXC
Fi e Retardant inishes C1 Improvement in the fire retardancy of plastic
ducts can be achieved to varying degrees and is wholly dependent llPOll the surface coating laminating resin selected and construction specification adopted In some instances smoke emission is coILSidered equaUy with other speci fication requirernen ts of the materials resistance to ignition and bumjng It is therefore important for design rs to establ ish the clients and officers detailed requirements and not rely on a tbird party interpretation of fire resisting or fire retardant Where possible the specification should refer dir etly to compliance with a British or European Standard identifying the specific sections applicable There are various types of resin and mat rcLnforcements that can achieve a Class 1 surface spread of flame ratin o when tested according to BS476 Part 7 (1987) This test puts materials illto Class I - 4 in descending order of perfoDllance according to the rat and extent of flame spread over their surfac under standard beating conditions Materials should also be tested for flre propagarion to BS476 Part 6 (1989) Tbi tesr measures the amount and rate of heat evolved by the material when subjected to standard heating
conditions Test results are given as an index of Perfonnance (i) whicb is based on three sub indices (iJ (i1) (h) The higher the value of the Index of Performance (i) the greater is the material s contribution to fire growth The higher the value of the sub-index 0) rhe greater the ease of ignition aod flame spread The highest product performance classification as defined in Approved Document B of the Building Regulations is Class O This is acLlieved if a material surface of a composite ploduct i~ either a) composed throughout of materials of
limited combustibility or b) a Class I material which has a tlre
propagation index (i) of not more than 12 and sub-index (i l ) of nor more than 6
01 J Class 0 is not a cla$sif1cation identified in any British Standard test
There are resin system reported to be classified to Class O when tested to BS476 Pcl1S 6 and 7 however designers need to ensure that such sysrems can be applied to their proposed design In propriety resinmat system available the fabrication techniques and COITect application are critical to the integrity of the reinforcing and clas ificatiol1 For example in some systems the u e of a non-fire retardant gelcont on a fire retardant substrate would reduce the classification For further information see HVCA publication DW144 Appendix D
55
DW154 SplCijiClIliol1 for Plastics Ductwork
x Guidance otes For nspectmiddoton Servicing a d
Clean-ng Access Openings
D1 GE ERAL This appendix highlight in ummary fOI111
the acce considerations that hould be made by the design r iD terms of inspection servicing and cleaning Having considered the seop and the design of the dUCI work system relative to the guidelines outlined below the designer should clearly indicate which levels of acces should be incorporated into the manufacture of a new duct work system (See Table 14 and Note I b low it
D2 DESIGN CONSIDERATIONS
D21 In ptction and servicing requireshyments are set out in Section 15 of Lhis specification
D22 Cleaning requirements are set out in the HVCA pubUcation TRl7 Guide to Good Practice Clean Lines of Ventilation Systems and the guide tates The precise location ize and
type of access would be dependent on the type of ductwork cleaning inspection and te ting metbods to b adopted Care protection and standards of cleanliness prior LO cOlllmisionin o
are set out in th AV A publication DWITM2 Guide to Good Practice Internal Cleanliness of New Ductwork Installations and th guide state Wh re specific limits of cleanliness are required ductwork sball be cleaned after installation by a spcialist cleaning contractor It will b in the interests of tht desioner botb financially and practically to cunsider employing a specialist c1eauing contractor at tbe
outset of a contract to internally clean newly installed ductwork prior to bandover This approach would reali e the following benefit shyi) Tb actual numb r of cleaning
access panels could be detennined to suit the method of cleaning to be adopted (This may be 1 s than the maximum requiremen listed under Lev 13 of Table 14)
ii) Clear directions could b given to the ductwork contractor as to tJle size and location of cleaning access panels that are required to be fitted during the mauushyfaclunng pro s
iii) The specialist cleaning operation prior to commi ioning vould enable the cleaning contractor to verify the practical acee requirement for the future cleaning operation associated -vitb a regular maintenance programme
iv) A specialist cleaning operation prior to commissioning would allow the designer to omit from the speeilicatiolJ the DWrrM2 requirem nt for factory sealing protection wipe downs and capping-off
v) Specialist Ieall ill 0 to the measurable standard defin d in TR17 will allow an objective definition of cleanline to be achieved
Car ful consideration must be gIven by the designer to the practl aJ problems associated witb the manufacture and fitting of suitably si Led access panel on small cross section duct and on the circular faces of rouod and flat oval ducts in particular
D23 Special con ideration must be given by the de igner to the practical problems associated with gaining personnel access to heavily congested ceiling areas and multi-la red du twork systems This approach would avoid
56
DW154 Spfciication for Plastics Ductwork
the possibility of access panels being D3 ACCESS 0 IN-LINE EQUIPMENT incorporated into a ductwork system at the This appendix unly covers acc il1spection manufacturing stage that were later found in through the ductwork body adjacent to an item practice to be inaccessible for either ervicing of in-line equipment and not openings in the or cleaning activities equipment itself
able 14 Acce requirements for inspection servicing and cleaning
HVCA PUBLICATIO REFE NeE (uidtgt 10 Gund Prartict
Adjace t OW144 Cleanliness orVcnlillltio S~lcr~ fRjJ7
in-line LeyeJ 1 Level 2 Level 3 ite sequipment pcdionSen lcin~ Section d C1eaniJl( SUn(O)lnspc lion Palle ltk~m_n
2011 (minimum OiL Jubje-ct to duct ~zel (ft~ -Panels
Control Da pcrs One (inspection) 203 One 300 mm x 200 mm Both sid Fire Dampers One (sCTjdJl~) 20211 One 300 0101 x 200 mm One side HeatingCooling Coils One (inspedion) 20213 One 300 mm x 200 mm (lIpstream) Both sides Attenuators (rectangular) None required One 300 mm x 200 mm (downstream) Both sides Attenuators (circular) one retluired One 300 mm x 200 mm (downstream) One side Filter Sections One (inspection) 20212 one required Uoth sides Air Turn Vanes None requjred None required Both sides Changes of Direction None required one required One side In-Duct FansDevices One (inspection) 20213 None required Both sides l
1 In the absence of any indication by the designer only Level ) access will be jncorporated into a new ductwork system
2 Tbe panel izes associated with Lev lis I and 3 acee s ar e middottablished by reference to Section 20 of DW144 and Section 2 ofTRll7 respectively
57
DW154 Speclfifatio for Plastics Ductwork
pA XE
B-bliography Included in this Bibliography are technical pUblications which may be of interest (0 ductwork designers fabricators and erectors and to tho e in the heating ventilatlng air conditioning industries generally nquiric should be made of the relevant organisation at the address quoted Since its publication other addresse contained within 0V154 mav have changed and some pubJicalions may have been superseded
HEATING AND VENTILATING CONTRACTORS ASSOCIATION
4 Palace Court London W2 4JG Telephone 020-7229 2488 Fax 020-7727 9268
Orders fo FlY A Publications Old Matlsion House Eamont Bridge Penrith Cumbria CA 10 2BX (Telephone 01768 864771 Fax 01768 86718) Email hvcapoblicationshvwelfarecouk DWn 44 pe ilicatiun for sheet mctal duclwork (Iow- mediulllshy
and high-pressure) 1998) DWIl4 A practical guide to dUGI ork I akage te ting
(revised 2000) DWII54 Specification for plastic~ duct rk DW171 Guide to good Practice for kitchen venlibtion system DW191 Guide to good pracuce glass fibre ductwoJk DwrrMI Acceptance cheme for new products - Redangolar cro
joint classification Guide to good pra tice - Internal cleanliness of new ductwork installations Guide to good practice for the design for the Installation of lire and smoke uampers
J 1Other puhlications
HampV safely guide 5th edition JS2 Tool box talks JS5 Weldlng Safety booklet JSI9 afety facts bo klet Fact sheets 1-24 2nd edition JS2J COSHH manual volume 1 Advice on compliance with the
regulations 1521A CO I-rH manual volume 2 Asses mcnt h ets JS23 Ri k management manual TR3 BrazinltT and bronze welding of copper pipework cUld sheet
(I 976) TR5 Welding of carbon steel pipework (1980)
TR6 Guide to Good Practice for Site Pre sure Testing of Pipework (19 0) Guide to good practice cleanliness of ventilation Ylem
CHARTERED IN TITUTlO OF BUILDING SERVICES E G EERS Delta House 222 Balham High Road London SW12 9BS rTelephone 020-8675 5211 Fax 020-8675 5449) CIBSE Guide Volume A Design Data Volume B In tallatiol1 and quipment Data Volume C Reference Data
CommlssioniJIg Codes These Codes eover the preliminary checkS eUing to work and regulation of vanous catcgories 0 plan The Codes give a guide to design implications Series A Air Distnbution Systems Series B Boiler Plant
ri s C Automatic Conlrol ystems Cr1es R Refrigerating Sy terns
Sene iN Water Distribution Systems
Technkal Memonllda TM 4 Design Notes for the Middle East TM bull Design otes for Ductwork TM 13 Minimi iog lhc Risk of egiounaires Disease
Research Reports RROI95 Ventilation system hygiene - A review of published
infomlatioo on lhe occurrence and ffects of Olltamination Rl~02J95 Air-to-air heal rec v ry RR0395 rnfluen e of HV C on smoke detectors
ATlONAL ENI [ERING SPECIFICATION LfMITED Southgatc hamber 3739 Southgate Street Winchester S023 9EH (Telephone 01962 842058 Fax 01962 R(8982) BUfLDING S RVICES RESEARCH AND [ ORMATION ASSOCIATIO Old Bracknell Lane West Bracknell Berkshire RG 12 4AH (Telephone Brackl1eU (01344) 426511 Fax 01344 487 -7 )
Application Guides AGln4 De tglJing Vana~le Volume middotylans for KOOnl
iir Movement AG1I91 Commissioning of V Sylcms in Buildings 11 6194 Fire Dampers
B) 94 cntiJalion or KitcneTls
AG389 The Commls ionin of Air Systems In Buildmgs AH2192 Commissioning of Bern - A ~ode of Practice TN2417 I Fire Dampec il) Ventilating Ducl
BEATING VENTILATING A AIR CONDITION G MA UFACTURERS ASSOCIATIO (HEVAC) HEVAC Henley Road Medmenham Marlow Buck SU 2ER (Telephone 01491 578674 ox 01491 575024 Emoimiddot infofetacouk)
Publicatjons Air Diffusion Guide Guide to Air Handling Unit Leakage Testing Guide to Good Practice Air Handling Unit Real Room Acoustic ~ st Procedure Specification for the ertiiicatioll ofAir Filters Method of Test for Water Rejection PerfOnTlatce of Louvrcs Subjected 1(1
Simulated Rainfall Test Procedure for Acoustic Loo cs Specification 10 Floor GrilJes - Types Performan e and Method ofTest Specification for the Determination of the Collection Efficiency of SilJ1d
Trap Louvre Domestic Mechwlical Vclltllalion Systems with Heal Recovery Fan Application Guid
~an and Ouctwork Installation Guide Guide to Fan Noise and Vibration
pecification of Requirements for JallJral Smoke and Heal Exhausl Ventilators
pecification for Powered Smoke and Heat Exhaust Ventilators
Specification of Requirements for Smoke Curtains Design Gujue of Smoke Ventilation for Single Storey Lodustrilll Building~
Including those with Mezzanine Floor and IIi Racked Storage Warehou es - Issue 3
Guidance for the Design of Smoke entilation YSlem for Covered and Undergrollnd Car Parks - lssue 1
Application of SOloke Control Equipment and Syst m Guid to Good Practice - Isue J
58
DW154 Sp(C~tiifitiol for Plastics Ductwork
BRITISH STANDARDS INSTIT TION Sales Department 101 P ntooviLle Road London NI 9ND (felephone 020-78 1 78801)
CP 413 1973 Ducts for building ervices
SS 476 Fire tes on building matenals and lruc(ure
Part 4 19 4 Non-combustibility lest or materials
Part 6 I Fire propagation lest for materials
Part 7 1993 Surface spread of tlarnJ tesls for materia
Part 20 1987 Fir resistance of elements of construction
Part 21 1987 Fire r sistlUlce of loadbeanng elements of construction
Part 22 1987 Fhe istallceofllon-loadbearing elemcllts ofconsttuclion Part 23 1987 Contribution of componcnts to the fire resistance 0 a
structure
Part 24t987 Fire resi lance of wl1lilation ductl
SS 5588 nan 919 0 Fire Precautions III thc desIgn and OOSlnJ lion of buildings
S 729 1971 Hot dip galvanized oatiugs (or irOIl aod stcel articles
BS 1449 Steel plate sheet and Irip
Pan 11991 Carbon steel plate heel and strip Part 2 1983 Stainless steel plate sheer and strip
and
B middotENJOI49-2 996 BSEN 10149- 1991)
BSEN 10131 1992
BSEN22063 Sprayed metal coarings 1994 Protection of iron and steel by aluminium and zinc against
atmospheric cOlosion Irotectiotl of iron and ste I against corro ion and oxishydation at elevared temperatures
BS 353 1981 Glossary of lerms relnting to thermal insulation
BS ISO 1479 Self-tapplngscrewsandmetallicdri c crew
B -lSO 7049
1994
B 4800 1989 Painl colour for building purposes B 4848 l0 rolled structural steel sections
Part4 1972 Equal and unequal angles BS 5422 1990 Specification for the use of therm illuating matcriulS
SS 5720 1979 ode of practice for mechanical veutilating and air C 11shy
dirionin bull in building
l3S PR 12814-1 Bend resting for plasric welds
SS PR 12814-2 Tensile testing for plastic welds
SS PR 13067 Appro altesting for plastic welds
BS PR EN I 100-] Vi ual in pection ofplaslic welds
SHEET METAL AND AIR CONDITIONING CONTR-CTORS NATIONAL ASSOCIATION INC (SMACNA) Headquarters 420 I Lafayeue Center Drive Chanlilly Virginia 2051-1209
Mailing Address pa Box 221230 Cbantilly Virginilt120 153-1230
Telephone (703) 803-2980 Fax (703) 803-3732
Accepted IJJdustry Pl3Gtice for Industrial Duct Constnlelion 197 ) i-rchitecmral Sheet kwl Manual ([993)
Comractors Guide lor Modification 10 ooslruerion Colllraets 1993 Ducted Eleclric Heat Guide for ir Handling Ssrerns (1994)
En~rgy ollservatioD Guidelines (1984) Energy Recovery Equipment yslClllS (199l
Fibrou GIns Duct onS1ntClion Standards (1992)
Fire Smoke amp Radiation Damper In tall Guide for HVA Syst ms (1992) Guide t leel Stack 1(95)
HVA Air Duct Leakage Test Manual (19 ) HVA COlllmissioning lvlanual (1994)
H A Duct Construction Standards-Metal amp Flexible (1995) Addendum 01 (Nov 1997)
HVA Duct Systems Inspection Guide (1989)
HVA ySlems-Application (1986) nVAC ByternS-DLlct D ign (1990)
HVi Systems-Testing Adjusting amp Balancing (1993)
indoor Air Quality Manual (1993) tcheu quipment Fabrication Guidelmes (1990)
Managers Guide for elding (1993)
Rectangular Industrial Duct Cons1TUction Standards (19 0) Round Industrial Duct oustmction Standards (1977)
Sei mic Restraint Manual (1991) (wl Appendix E 1993) SMACNA Ma le Index ()fTechnical Publications (1995) Tbennoplnstic Duct CPY ) Construction Manual 1994)
DEPARTME OF THE ENVIRO MENT (Publications Centre) H Stationery Oflice 5 Nine Elms Lane London SWS 5DR
MampEJ 011972 Electrical in tallat1011 in buildings ( ew Editiou)
IampE 0319 Healing hot and cold wat r steam and gas losla1lations for buildings
M amp - No4 1970 Central heating and hot and cold ~ ateT in tallations for
dwelling
M amp ENo100 1971 Mechanical ventilation for building~
ASSOCIATION FOR SPECIALIST FIRE PROTECTlO As ociation House 235 Ash Road AJdershot Hampshire GUl2 4DD
Telephone OJ25221322 Fax 0 J252 333901
lublicalioos Fire Ratcd and moke Outlet Ducrwork An Industry Guide t Design and InSlalla lioll
HEALTH AND SAFETY EXEC TIVE Rose Court 2 Southwark Bridge London SEl 9HS Telephone 020-7717 6000
TWJ THE WELD G TlTUTE Abington Hall Abington Cambridge CB16AL Telepbone 0 J223 89162
Publication DatJ Oil w~ldll1g of lhermopla lics
59
DW154 wciiwlioll for Plastics Ductwork
A -=--DIX
Factors
Specific gravity shy pp = 091 approx UPVC = 14 approx
Some miscellaneous conversion factors
To convert
Length Inches to millimetres Feet to metres
Multiply by
2540 03048
To convert
Millimetres to inches Metres to feet
vIultiply by
003937 3281
Area Square inches to square millimetres 6452 Square millimetres to square inches 000155 Square feet to square metres 00929 Square metres to square feet 10764
Volume Cubic feet to cubic metres Cubic feet to litres Gallons (UK) to litres
002832 2831 4546
Cubic metres to cubic feet Litres to cubic feet Litres to gallons (UK)
35315 00353
022
Mass Ounces to grams Pounds to kiJograms Tons to tonnes
2835 04536
1016
Grams to ounces Kilograms to pounds Tonnes to tons
003527 2205
09842
Volume flow Cubic feet per minute to cubic Cubic metres per second to cubic
metres per second 0000472 feet per minute 2119 Cubic feet per mIDute to litres Litres per second to cubic feet
per second 04719 per minute 2119
Motion Feet per minute to metres per second 000508 Metres per second to feet per minute 197
Pressure Inches water gauge to millibars 2491 Inches wateJ- gauge to pascals (Pa) 2491 I Pa = I ewton per square metre = 10-2 millibars
60
Heating and Ventilating Contractors Association Esca House 34 Palace Court London W2 4JG
Tel 020 7313 4900
e-mail contact Itvcaorguk web site wwwhvcaorguk
Fax 020 7727 9268
DW154 Specificatiol for Plastics Ductwork
8234 The joint face and the filler rod surfaces must be clean and grease fre and preferably roughened b shyfore welding In particular any deposited filler rod that is charred mu t be scraped away before additional runs are added
8235 The numbers of runs of fi lIer rod shall be sufficient to give a thiekne s of era s section of the veld at least equal to the thiekn s of the sheet
8236 Where high frequency park testing i specified lhi shall be undertaken in accordance with tbe weldshying in tmction handbook
Note A full descriplion of welding method is given in the Welding Institut handboo entitled Data on Welding of Thennoplastic Relevant BS amp CE Standards are prEN 12814-1 amp 2 prE 13067 and prE 13100-1
824 Completion of compo ite laminate joints Following solvent ementing or hot air welding of joints campi tion of any specified external laminate shall
carried out to maintain thebe
825
integrity of the construction (S 8227)
Gaskets These can be fabricated from various materials in the form of a pre-formed roll she t or trip applied between opposing faces of fbnced ross joints It i a visable to select material r commended by th ga ket manufacturer for the pecific appucation intended
PART 3
Rectangula ucts
9 RECTANGULAR DUCT SIZES
91 This specification covers duct size up to a rnLltimum longer ide of I -00 mm Duct size with an a peet ralio greater than 4 I ar not recommended Although they offer no problems of construction they increase friclionaJ resi tance and the pos ibility of Dois
10 CONSTRUCTION
101 General Th minimum constructional requiJement r r UPVC and PPPPS un-reinforced are hown in able 2
102 Longitudinal seams Longitudinal seams should Dot be located at corners or in the underside of the duct
103 Sheet jointing seams Seams shall be joined by continuous filler rod hot air welding or by fl1sion Vi ldiug only other form of jointing are not acceptable
104 Socket and spigot joints Sock t and spigot joints shall be formed by purpoe made double cket pi ces 100 mm long and of the ame thiekne material as the duct welded into position on each standard length of duet forming 50 mm de p sockets prepared and ready for final jointing on site with filler [Od of the ame formulation used for prefabrication (See Table 2)
105 Flanged joints
1051 FJa ges Fabricated flanges shall b con tmeted u ing miniumum of 9 mm thick by 50 nun wide material of matching formulation depending on duel size as hown in Table 2 The flange hall be mounted true and square to the duct surface and w lded on both sides a 103 and Figs 3 4 Alternative con truction Illay be
11
DW154 Spedjicfltiotl for Plastics Ductwork
utilised for attacllment to plant or other equipment
1052 Drillings Drjllings shall be placed to permit clearance to tbe extel11al casing and any reinforcement of tbe ductwork for the application of fastening
1053 Fastenings For nonnaJ application bright zinc plated bolts nuts and vashers hall be Llsed in sizes and pitch centres shown in Tabl 3 Where special conditions prevail consideration of other material finishes such as stainless steel bolpounds nuts and washers may be used In all cases gasket materials as Section 825 shaLL be used
106 Expansion joints Wher the configuration of the ductwork does not provide for movement due to temperature change or where such movement is restricted by branches or attachmenL expansion joints should be specified by the designer (See Section 18 FlexibleExpansion joint connections)
It is the re ponsibilir-y of the designer to identify the positions of any necessary expansion joints hased upon design param ters for the individual systems (See Figs 23 to 25 34 amp 35)
Design ote xamples of expansion joints shown in Figs 23 to 25 are not suitable for movement exceeding 30 mm
107 StilJeners
1071 External stiffeners Shall be fitted as specified in Tables 2 amp 10 and Figs 5 amp 6
1072 I temal stiffeners The u e of internal stiffening or bracing shall be acceptable iJ deemed necesary and approved by the designer (See Fig 7)
11 FITTINGS
111 Standardisation of fiuings The terminology and descriptions of rectangular duct fittings a et out in Section 25 are recommended for adoption as standard practice to provide common terms of reference for desi crners quantity surveyor and ductwork contractors and for those using computer in ductwork design and fabrication
Bend are designated as hard or easy and the e terms as used herein have the folJowin o
meanings
Hard signifies rotation in the plane of tb longer side of the cross ection
Easy signiiies rotation in the plane of the shorter side of the cros section
An example iIlu trating these term ] given in Fig 8
Fitting are fabricated by cutting and welding sheet
112 Stiffeners Shall be as 107 and Tables 2 amp 10
113 Splitters Shall be as shown in Fig 41 and welded as 1003
114 ruing vanes Where square bends are required turning vanes as shown in Fig 9 hall be fitted
115 Branches When fitting branch ducts to a main duct care should be taken to ensure that the rigidity- of the duct panel is maintained in terms of tbe sti ffenillg criteria
116 Change shapes Where a change bape is necessary to acconUllOdate the duct and the cross- ectional area is to be maintained the slope haU not exceed 225deg 011 any side (See Figs 52 to 56) Where a change in shape includes a local reduction in duct cras - ectionaJ area the slope should not exceed ISO on any side and tbe reduction in area should not exceed 20 Where tceper angles are necessary due to ile
12
DW154 Spec([icatirJ1l for Plastics Ductwork
restucllOn splitters shall be provided Taper Transformation pieces from circular 10 square pieces reducers and transformation piec s or rectangular shall be made as long a shall be manufactured from the tbickl1 s of p sible and uJe angl ball be uot mor than material specified for the larger size ducl 225 (Fig 55)
loon Pa 1500 Pa
2 3 4 5 6 mm mm mm mm
3 socket amp spigot - - -or tlanged
as Figs 1 2 3 401 to 600 45 flanged 50 x 9 flat 1200 800
50 x 9 flat welded both sides a Fig 3 as Fig 5
601 to 1000 45 flnged 50 x 9 flat 800 600 50 x 9 flat welded both sides as Fig 3 as Fig 5
1001 to 1500 6 anged 75 x 9 flat 600 600 75 x 9 flat welded botb sides as Fig 3 as FieJ 5
or or 70 x 70 x 9 angle 50 x 50 x 5 angle
as Fig 4 welded both sides as Fig 6
N t For constructional operating temp rature limits refer to Part 2 Clause 54
Longer Pitch Bolt Size
Side max 2
mm 1m mm Up to 400 100 8 with washers 401-600 tOO 10 with washers
601middot1000 100 10 with wash rs 1001-1500 100 10 with oycrsized
washer
13
Table 2 inimum con tructional requi ments - rectangUlar nmiddotreinforce UPVC and pp
Joints Sliffeners Maximum spacinOLonger Side MillirnUlll She t between
Thickness Joint~S(iffi ners
mm Up to 400
DW154 SpedflCiltion for Plastics Ductwork
Cross joint - recta gular ducts
Fig 1 Socket and spigot joint (UPVC and PP)
Conlinuou weld joint on sile onlinuou- wcld
CT~r~T2
Fig 3 Flange joint (UPVC and PP)
ontinuou weld
Fig 2 Socket and spigot joint (UPVC only)
Fig 4 Flange joint (UPVC and PP)
S iffeners - rectangular ducts
Fig 5 Flat Fig6 Angle
Oatim wo]
Fig8 Bends - examples of hardTie rod assembly and easy
Hard
Fig7 With spacers Easy
4
DW154 Speci(uariml for Plastics Ductwork
Fig 9 Turning Vanes
HOWl G TYl AL EXAMPLE OF FOCI G
15
Ma vane length shy 615 mm
Example ofbraemg when V1IIle length exeeed max pennined Ahematively two banks of ncs fixmg the centre rail together at ] 50 mm nrrcs
U~_II---- fixed to dnct wall both CDds
bLEVATION
vane
Maximum distance between centrc oflUming vanes should [Jot exceed 60 mm pitch
DW154 SPCCijicllfiull for Plastics Ductwork
practice to provide common terms ofPA T4 reference for designers quantiry urveyor and
Circular Ducts
12 CIRCULAR DUCT SIZES Th duct sizes [n Table 4 have been selected from the ISO and C standard ranges as the 132 preferreod sizes
Table 4 Circular ducts shystandard extruded tube sizes
133 Extruded tube
ISO Standard Sizes (Nominal Diameter) 11
Wan Wall Thickness Thickness
mm mm mm mm 110 500 4022
I25160 600 50 I25200 630 60
225 25 700 60 13425250 800 63
280 900 70 315
23 23 80
355 1000
25 1250 104 400 32 1400 108 450 35
Note The above sizes are subject to normal manufactl1ring tolerances Other size may be available in varying wall Lhicknesses and subject to test and operational pressure
13 CONSTRue ION
13 General Tllis specification covers duct sizes up to a maximum diameter of 1500 mm The minimum constructional requirements for UPVC amp PPPPS un-reinforced ducts sball be as Tables 6 amp 7
ductwork contractors and tho e using computers in ductwork design and fabrication The requirements for circular duct fittings apply throughout the size ranges covered in this specification
Sheet jointing seams Seams shall be joined either by continuous fLiJer rod hot air welding or by fu ion welding Other forms of jointing are not acceptable
Socket and Sl)igot joints Socket and spigot joints shall be formed by purpose made double socket pieces 100 mm long and of the same thickness material as tJJe duct welded into position on each tandard length of duct forming 50 mm deep sockets prepared and ready for final jointing on ite with PVC adhesive andor fill r rod of the same formulation used for fabrication
Flanged joints
1341 Flanges abricated flanges shall be conshy
structed using minimum of 9 mm thick by 50 mm wide material of matching formulation depending on duct size as shown in Tables 6 amp 7 The flange shall be mounted true and square to the duct surfaces and welded OD both sides a 103 and Fig 12
1342 Drilliogs Drilling ball be placed to permit clearance to the external casing and any reinforcement of the ductwork
1343 Fastenings For normal application bright zinc plated bolts nuts and washers hall
16
For srualler diameters preformed fittings are available otberwise fitting are fabricated from segments of duct or sheet welded together
The terminology and description of circular duct tiltings as set Ollt in Section 25 are recommended for adoption as standard
be used in sizes and pitCh centres shown in Table S Wh re special conditions prevail consideration of other material finishes such as stain le steel bolt nuts and wasbers shall be u ed In all ca cs gasket materials as Seciion 825 shall be USed
DW154 Speciliwriml for Plastics Ductwork
135 Stiffeners
1351 External stiffeners Shall be fitted as specified in Tables 67amp 1 I and Fig 13
1352 Internal stiffeners The use of internal stiffening or bracing hall be acceptable if deemed neces ary and appn ved by the designer
f 36 Expansion joints Where the corrfiguration of the ductwork does not provide for movement due to temperature
Cross joints - circular ducts
change or where such movement is restricted by branches or attachments expansion joints should be fitted (See Section 18 Flexible Expansion joint connections)
It is the responsibiLity of the designer to identify the position of any necessary expansion joints based upon design parameters for the individual systems (See Figs 23 24 2534 amp 35)
Design Note Examples of expansion joints shown are not suitable for movement exceeding 30 mm
Fig 10 Socket and spigot joint (UPVC and PP)
ConLinuous weld joim on ite Ontinuous weld
crlr~l
Fig 12 Flange joint (UPVC and PP)
Continllous wcld
boil
Continuous weld or Solvelll cement
Solvelll ccmcnl joim on sile
Fig 11 Socket and spigot joint (UPVC only)
Stiffeners - circular ducts Table 5 Fastening centres shycircular duct flange jointsFig13 Flat
flat conljnlJou~ly welded Diameter Pitch Bolt Size
max
1 2 J 11
1 shy -~
mm mm mm Up to 600 100 8 with washers
601middot1000 100 10 with washers - ---I
1001middot1500 100 10 with oversized washers
1
Minimum offourfixings
17
DW154 Specifiiutiofl for Plastics Ductwork
Table 6 constructional quiremen s - circular unshy inforced U VC
Diameter Minimum Joints Stiffeners Maximum spa ~in r
Sheet between Thickness Jointsl tiffcners
1000 Pa 1500 Pa
1 2 3 4 5 6 UD mm mm mm mm
UO to 600 3 socket amp spigot as Figs 10 11
or fla ged Fig 12
601 to 1000 45 socket amp spigot 50 x 9 flat 2400 2400 as Figs 10 11 welded bo sides
or Oanged as Fig 13 as Fig 12
1001 to 1500 6 Hanged 75 x 9 flat 1200 1200 as Fig 2 welded both ides
as Fig 13
Applies 10 Tables 6 alld 7
Note 1 For constructional operating temperature limit refer to Part 2 luu 54 2 To allow for conicleration or extruded se lions or fabricated component the materia] tllicknes i hawn a nominal
Table 7 Minimu onstrucfional requirements shy circular un-reinforced PPS and
Diameter Minimum Joints Stiffcners Maximum pacio Sheet between
Thickness Join sStiffener 1000 Pa 150n Pa
I 2 3 4 6 mm m m mm
110 to 500 3 socket amp spigot as Fig 10 or flaoged as Fig 12
501 to 750 45 ocket amp spi~ot
as Fi 10 or Uanged as Fig 12
751 to 1000 6 tlanged 50 x 9 Oat UOO 12 0 as Fig 12 welded nth sides
as Fig 13 1 1 to 1250 6 flanged 75 x 9 flat 800shy 800
as Fig 12 welded both sides as Fig 13
1251to~ flangcd 75 x 9 Oat 600 600 as Fig 12 welded both sides
as Fig 13
18
DW154 Sped(icalirm for Plastics Ductwork
PARTS
Hangers an Suppo ts
14 GENERA
141 Supports are an e sentiaJ part of me ductwork system and their supply and in tallation are normally the responsibility of the ductwork contractor The principl s are a I-rvCA publication DWIl44 Part 6 Section 19 and should be read in conjunction with this document
Design Note Designers may pecify specific requirements wbich will supersede guidance given in DW144
142 Rectangular ducts abl 8 give the- minimum requirements for
hanger and supports for un-reinforced ductwork
143 Circular ducts Table 9 gives the minimum requirements for hangers and upports for uD-reinforced ductwork
144 Vertical d cts The design of supports for vertical duct is dictated by site condition and where practical duc hould be upported at 4000 mm interval or where tbey pa s through a floor (but n ver exceeding 4500 mm) see Figs 17 amp J8
145 External ducts Where ducts are external to buildings and may be ubject to wind loading support should be plac d so as to restrain ide tl1ruSt and should allow axial movement as neces ary It is the respon ibility of me de igner to calculate the effect of the particular prevailing condition and to define any special upport requirement
146 Expansion joints Support shall be designed to permit axial movement only and shall e provided on eitl1er ide of expansion joint
I 1shy
I~
mm -Jp to 400
401 to 600 601 to 1000
Table B Hangers and Supports - rectangular horizontal ducts
Hanger Bearer Drop Roll Formed Rod
Long r Side
Cbannel ~-shy ~
---shy
Maximum ~pacing
4 52 3 _ -c Fig 15 - Figs 14 15 16 amp 2J
shy
mmm mmmm 240025 x 25 x 16 40 x 20 x 15 8 240040x20x15 40x 20 x 15 10 240040 x 20 x 1~510 40 x 20 x 15
shy
I
40 x 40 x 15 40 x 40 x 15 24001001 to 1500 I 10
Table 9 Hangers and Supports - circular horizontal ducts
Longer Side Hanoer Split Clips Maximum spacing Drop Roll f-ormed and Wrap-round Rod ~hannel Hang r
2 3 4I Fig 1920 amp 22Fig I
mm mmmm mm mm 25 x 25 x 15 IIp to 355 8 40 x 3- --1-_ 2400
2400
2400 2400
70x 6
40 x 5 SOx 5
40 x 20 x 15 40 x 20 x 15 40 x 40 15
10 10 10
356 to 600 601 to 1000 1001 to 1500
19
DW154 Spccijicutioll for Plastics Ductwork
147 Protection specification Any special coatingpaint Unless otherwise stated all support shall be finishes for protection against hostile manufactured in material as specified in this environments shall be advised by the designer
SUPPORT BEARERS
~ 14 Flg16 Inverted profile
angle I ~lIed steel
channel (alternatives) Fig 15 Profile channel (alternatives)
TYPICmiddotAL VERTICAL DUCT SUPPORTS Flat bar clipStiffening frame Outline ofinsulation stiffening frame or tlanged joint (if applicable) or flanged joint
Stiffening framc or flanged Joint
~~-I ( ee notes 10) I
r--~ -++- ~--4==J===4~---
Fig 17 Vertical rectangular ducts Fig18 Vertical circular ducts
The support bearer which depending on ducti tructural opening size could be either channel or angle section may be ll1ilised in any of the following arrangementsshy
a) To support the underside of a flat bar clip in halves (circular)
b) To support the underidc of either the stiffening frame oftbe flanged joint ofaoy duct section
c) To support either a stiffening frame Or a flanged joint below nsing drop rod srudding
20
DW154 Spediraiml for Plastics Ductwork
Arrangement of bearers and hangers (to be read in conjunction with Table 8 amp 9
wbich list material sizes relative 10 duel izes)
KEY Limits refer to actual duct size - insulation is additional - Typical
attachmentv -Atta hment t strucUlrcI to strucUlrc
I I
I - Flat Bar
I - Drop rod or - utlinc of lllddmg In ulillwn (if
applicable)
Alternative 7 drop rod or rt------------ 1 studdmg q I
I I Rectangular
ii i n 1
Fig 21 Rolled or profiled bearer Limit oncFig 19 Wrap-round hanger Limit 55 DIA
V v Drop rod orAllernaUC 1 1 tudding
drop rod or 1
-- -- 1studding and elded bas 1
I I0 -_
Limit 355 DIA Frg 22 Split clips Limit 1500 DIAFig 20 Flat strap hanger amp split clips
21
DW154 Specification for Plastics Ductwork
6PA deElned in J62 appropriate to the airflow pressure acoustic temperature and corrosion
General
15 ACCESSl SPECTION OPENINGS
151 General These are for inspectionservici ng on 1y
HVCA publication DWIl44 Part 7 - General Section 20 sets out the requirements for access applicable to this specification
152 Cleaningmaintenance Designers shall take specialist advice and then stipulate their requirements for the periodic internal cleaningmaintenance of ductwork and of the consequent need for adequate access for specialist cleaning equipment including the size type and locationfrequency of the actual access openings required
Appendix D sets out guidance notes for the consideration of cleaning access and also makes reference to the HVCA publication TR 17 Guide to Good Practice Cleanliness of Ventilation Systems which covers the su~ject
in greater detail
Note A majority of in tallations in which plastic ductwork is used are considered to have a nigb operational risk potential and provision of access should address this
16 REGULATI G DAMPERS
161 General Balancing dampers and control dampers are elements inserted into an air di tribution system or element of an air distribution sy middottem Balancng dampers permit modification of the air resistance of tbe system and consequently cbanging of the airflow rate Control dampers control tlle airflow rate and may in addition provide low leakage closure of the airflow
The deigner shall specify damper locations taking into consideration that good design practice requires a minimum of five times the diameter or width of the shortest side of uninterrupted flow between plant connections and the damper and select the damper type as
characteristics
1611 Balancing damper To achieve the required distribution of air in the ductwork system at inlets andor outlets for [hi purpose the damper blades are set and Jocked manually in position between fully open and fully closed
1612 Control damper To secure dynamic control of the air now in the ductwork system In thi function the damper will always be power actuated and may require to be modulated between fully open and fully closed and to be capable of taking up any position between these extremes In the fully open position the damper should have a minimum pressure drop In the fully closed position it will not necessarily achieve a complete shut off
162 Types of airflow control dampers Airflow dampers of various types are available for specific purposes as follows
1621 Single - blade dampers Single-blade dampers shall consist of a si ngle pi voted blade cOlllained withjn a casing or section of ductwork The blade shall be adjustable tbmugh a nominal 90 angle by means of a quadrant or similar operating mechanism Where automatic control of the damper is required the spindle shall be extended to enable a powered actllator to be mounted
Single-blade dampers shall have a maximum duct width of 400 nUll and a maximum duct height of 400 mm for rectangular ducts and for circular ducts a maximum diameter of 400 mm
1622 Multi-blade dampers Multi-blade dampers shall consist of a number of pivoted blades contained within a casing The blades shall be
22
DW154 Sedicalirm for Plastics Ductwork
adju table through a nominal 90deg angle simultaneously by intershyconnected linkage or gears connected to a quadrant or similar operating mecbanism Where automatic control of a damper is required a spindle shall be extended to enable a powered achlator to be mounted
There is no restriction on the size of duct in which multi-blade dampers or damper assemblie may be u ed Where dampers are required for blade lengths in excess of 750 mm the blades should be suitably reinforced or supponed 0
individual damper blade should exceed 200 mm in width
1623 Iris dampers Lris dampers shall consist of a nUlllber of radialty interconnected blades which open or close within a casing with duct COlll1cctions The blade shall be simultaneously adjusted by a quadrant or similar operating mechanism
Iris dampers shall be installed as specified by the manufacturers operating and installation instructions where the product is unidirectional with regard to airflow
lris dampers are available for circular ducts only in diameters up to 250 mm (it should be noted that the damper casin i appro)(imately twice the diameter of the duct)
1624 Backdraught dampers Air pressure operated uni-directional rectangular (single or multi-blade) with adapters if fitted to circular ducts
1625 Slide and blast gate dampers A damper [lsed as a shut off facility with an externaJ Lide bousing allowing the blade configuration to be fuJly inserted to fully extended for maxiDlUlll air flow
163 Construction
1631 Materials All products shall be protected against cOHosion as necessary and supplied in a fully finished condition as specified by the designer
1632 Dampers used in low and medium pressure systems The following recommendations apply to dampers forming an integral part of ducrwork with pressure classifications A and B air leakage limits
The dampers shaH be constructed to minimise distortion and prevent jammin in operation Th blade shall be sufficiently rigid to minimise movement when in the locked pOSitiOLl
The blades shall be securely fixed to the operating mechanism All balancing dampers shall have a locking device located on the outsid of the case and shall giv clear indication of the actlwl blad position All penetrations of the duct shall be fitted with suitable seals where necessary
1633 Dampers used in high pressure systems Regulatino- dampers used in duc[work sy tems to pressure cJassification C shall meet tbe construction requireshyments specified in 1631 and 1632 with operating mechanisms out of the air-stream
1634 Proprietary types of damper The use of any specific type of proprietary damper shall be confirmed by the designer In all cases proprietary dampers shall meet the relevant requirements of thi specification
1635 Damper casings Duct damper casings hall be constructed to meet th mllllmum
23
DW154 SpeciJimlioll for Plastics Ductwork
leakage Iim its sp cified for th c1uctwork ystem to which tbey are installed
In order to apply the square metre leakage calculatio as detailed in DW143 A Practical Guide to Ductwork Leakage Testing the reference casing area ball be taken as the perimeter ize of lh damper IDultipli d by the equi alent length of Imetr eg an 800 mm x 400 mm duct damper hall have a surface area for casillg leakag p donnan calculated as follow (2 x 08) + (2 x 04 x I
=24m2 casing area
Other pelforlllance ancl rating test methods for damp f and valves are specified in ISO 5129 and BSIE 1751 and are referenced belm a) Leakage past a closed damper
alve BSIE 1751 b) low ratepre sure requirement
characteri t cs BSIE 1751 c) Operational torque le ring
BSEN 1751 cl) Thermal transfer testing
BSIEN 17 I e) Reg nerated sound power levels
ISO 5129
164 Installation Dampers shall be imaalled in accordance will) any re Ievant ISO EN or British Standard 10 aJ bUT lcling regulation and national code of practice as well as the manufacturers recommendations
17 FIRE DAMPERS AND INT MESCENT SLEEVES
171 General Damper or sleeves arc requiTed on duct y~telll where the designer has -tjpulated the
duct wiU penetrate a fire compartment in the majority of application tbermopla ti ductwork is ugtecl where contamlDated corro ive or otherwise exceptional fumes are concerned it is preferable to use tire damp r which are externalJy mounted ie of the intmnescent operated crush typ
24
72 Fit-e rating The damper assembly should have a fUT
resi tance ratin o equal to that of the fir ban-jer it penetrate and ball be fire tested and rated to the timetemperature curv of B 476 Part 20 and 22
173 Intumescent sleeve At the time of writing this specification qualified test results were available for rectangular dampers and circular dampers up to 55 mm diamet r Manufacture have indicated that they are able t provide speci fications for other size and diameters This infonnation should be confirmed b th de igner Various type are available includino
tho e incorporating ruechanical closing plate and those operated anI by expanded iJllUme c nt media
In all ca es fire damp rs and intnmeBcen leeves shall be supplied and in taUed in
accordance with the manufacturer iJlStructioos and COSHH a essm nt
174 Other types Fire dampers of mious types are availabl for specific purpose~ ee HVCA publication DW144 The de igner should )lot (hat materials for con lt1Jction bould be uitablc for the par1icular application
ALL C SES FIRE DAMPERS AND fNT MESCENT SL _VES SHALL HE S PPLTED AND INSTALLED IN A ORDA CE WITH Tf--IE MANUshyPACTURERS STRUCTTONS AND COSHH ASSESSMENT
18 FLEXIBLEEXPANSION dOINT CONNECTIONS
181 General ploperties Tbe material u ed for flexibleexpan ion iojnt~
mu t meet the design r requirements for temperature air pressllrelfe resistance applicable to pl astic duct sy tem vibration and noi e br akout when incorporated into a jointconnection and shall comply ith lh standard of air-tigbtne specifi cl for the duct work sy tem of which it fOlms part (See Figs 23 24 5 26 27 amp 28 for typical con truclion clelai Is
DW154 SJecilimtol for Plastics Ductwork
Expansion joints
Fig23 Moulded bellows type (rectangular and circular)
Fig24
~F aiblc sleeve
__ liding sleeve
~~~~
Sleeve type (circufar)
Fig 25
AIRFLO
COnlinuou~
weld~
Flexible Iceve
PV A HOWN pp SE BACKING FLATS AS FIG 2
Sliding lee c Co1linuou
weld
Flanged sleeve (rectangular and circular)
25
DW154 Specificatiol for Plastics Ductwork
Flexible con ections
Fig 26 Flexible sleeve with clips (UPVC and PP)
--__ Flexible I eve
I
I
I CODn clioD to plant ~
Band clip
Fig27 Welded flexible sleeve (UPVC only)
Plastic)sed PVC slceve ~-- onll11uo1sly welded
onrreclion to planl ~
Fig28 Flanged flexible connection (UPVC and P )
t sp dally moulded flexible flanged connCClitlll
boil
C)nneclion to plant ~
26
DW154 Specificotiol for Plastics Ductwork
182 LOClt1tion Flexible joint are typicltllly lIsed at building expansion joint and fan inletsoutlets Any others required should be indicated on the de ign drawings Care should be taken to maintain alignment across jointsconnections
183 Length Flexible Jomts shall be kept as short as pra middottieable above a minimum eft ctive length of SO mm In no ca e shall a flexible joint exceed 250 mm in lengtb
184 Connections to rectang a ducts With flanged rectangular connections Ule tlexible material shall be held in pLace with flat pIa tic strip of not less U1an 6 mm thick ltlttached to the flanges using uitabJe fixings The more heavy weight type of fleAible mateLial may also be obtained formed into a channel ection with corners fitted to give a neat air tight j int For pigot connections the Be ible material shall b held in place with flat pIa tic trips n t less than 6 mm thick
t 85 Connections to circular ducts With tlanged circular connections the flexibl material shall be held in place with flat plastic backing strips or proprietary clip bands with screw or toggle fast ners
186 Welded flexible connections (Rectangular and Circular) Where the parent and llexibl material are from imilar ba ed products they can be joined to the duct u ing the welding method described in Section 823
19 PROTECT VE FINISHES
191 nles otherwise stated all ductwork shall be mallllfactured in mat fial as pecified in tbis specification Any special coatingpaint fmishes to be provid d by the duct work contractor sball be advisd by th de igner
20 CONNECTIONS TO BUILDING OPENINGS
201 Fanning and finishing building op nings are not the repoJlsibjlity of the duftw( rk contractor and the note that follow are for guidance purpo e only
2011 Openings in brick block or concrete walls shall have inset frames to provide a suitable means of fixing grille louver masking flanges or the tlanged ends of ductwork The illset frames shall be conslnlcted to maintain the structural int grity of the wlll and where applicable cavities shall be suitably lined
2012 Openin s in dry linino partItIons shall have inset frames a 2011
2013 Openjngs in cladding walls and roofs shall have flaoged leevesframes to provide a suitable means of fixing a 2011
2014 Horizontal and vertical opening xposed to oLltside atmo phere hall
be provided with a suitable weathering fini h at the external face especially where profiled cladding is used
2015 Timber framed op nings are not permitted In fj re compart ment barriers
202 Ductwork connections to building openings hall have a flange of suitable profile to permit practical fixing to the openillg frame In selecting the profile consideration shall be given to Tabl~s 2 and 10 in this specitication relating to duct ize and rating Gasket strip or sealant shall be ltlpplied between the tJaoge and building op ning frame
21 DISCHARGEEXHAUST TERMINAL
21 Tbese shall be vertical open ended and designed to meet and comply with current r gularions on contaminated flue The designer hall ensure that the de ign and perf rmance i suitable for its intended purpose Examples of some typical terminal designs are SbOiD in Figbull 102 10 bull 104 amp 105
27
DW154 SpedjimioTl for Plastics Ductwork
22 THERMAL INSULATION
221 The provision and application of thermal insulation to ductwork is not the responsibility of the ductwork contractor
222 Where ductwork is required to be preshyinsulated the specification should be agreed with tbe designer
223 Where the temperature of the air within the duct promotes condensation on the exterior surface of the duct and cause moisture penetration througb the thermal insulation vapour scaling may be required and in this case the most important requirement is to limit penetration of the seal
The extent of any vapour sealing of ductwork thermal insulation and the support method to be u ed must be clearly pecitled in advance by the designer
224 For detailed information on the thermal insulation of ductwork reference should be made to BS 5422 1990 which covers the specification for thermal insulation materials on pipes ductwork and equipment (in the temperature range -40degC to +700degC) and BS 5970 1992 which is a Code of Practic for Thermal Insulation of Pipework and Equipment (in the temperature range -lOOdegC to +870degC)
23 FIRE RETARDANT FINISHES ON PLAST C DUCTWORK
231 The designer should note tbat ductwork constructed to DW154 has no teted fire rating or information see Appendix C
24 REINFORCEMENT OF DUCTS WITH GRP LAMINATE
241 General Where ductwork is required in larg T izes than are covered by Tables 2 4 6 amp 7 or with the increased strength sometimes necessary for industrial use external reinforcement is normally pwvided by applicatioD of glass fibreresin laminate
GRP systems will bond satisfactorily with standard UPVC sheet but for pp it is
nece sary to use a specially prepared sheet with a glass fabric backing incorporated dOling manufactllfe
The detailed techniques of fabrication using GRP are outside the scope of this speci lcation but the following notes are offered for guidance of ductwork fabricators
242 Materials
2421 Quality The laminate is made up of polyester resin complying with BS 3532 and glass fibre complying with BS 3496 or BS 3749 The nominal ratio of resin to glass fibre should be 7030 by weight
2422 Minimum properties The laminate shall comply with the followiog mini mum pbysical properties
Tensile strength - 70 MNm Tensile modulus - 7 Gl m Flexural strength - 140 M Im Bond strength (hetween laminate and substrate Not less than 7MNm Bmcol hardnes Not le s than manufacturers specification
The GRP reinforcement educe the expansion of the parent material but the resultant stre ses arc well within rhe strength of the bond However the Iinear thermal expansion curve shown in Figs 34 amp 35 will serve as a guide
Surface resistivity electrkal propcltles and acoustical propertie are similar to the relevanl unreinforced materials The fire retarding properties of GRP may be improved by the use of specialisl laminating resin
2423 Forms available GRP Laminate should be built up from the separate materials ie resin aod glass fibre in the form of chopped
I strand mat or spray ravings
28
DW154 Spcification for Plastics Ductwork
2424 Workshop conditions Polyester resuls are sensItIve to lmperature and the workshop hould b maintained at a temperature of herween 20deg and 25degC HiOh relative humidities and damp onditions should be avoided A good rate of air change must be pro icled pJeferably by m chanical ventilation
2425 Storage of materials Resin and urin o agents shouJd be stored in dark cool condirions away from the working area and in confonnit with statutor requireshyments for tJle middottorage of flarmnable liquid Because of Ule Limited torage lif of the unmixed resin and curing a eot mal lials ~hould be ch eked before use to enLlfe that they are within the manufacturer pe ified sh If life (usually ix month from the dm of manufacrure)
Glass fi re should be stored separately und r clean dry conditions
243 Surface preparafon
2431 UPVC To achieve the specified bond strengtll the urface to which the GRP is applied mut first be thoroughly cleaned and then etched either by mechanical means or by the use of a suitable solvent
2432 pp with glass fabric backing To achieve the specified bond middottrength the fabric backing must be thoroughly impregnated Witll resin
244 Mixing the materials for use The re in 1 a three part mix compri lng base I sin hardener and accelerator The manufactur rs pecj[ied proportions are critical and th llUxmg sequenc pecified must be meticulously foUowed
The resin has a very limited life after mixing and before u e It is dependent on the characteri tics and bulk of th resin the alllount of hardener the degree and method of acceleration and the workshop onditions
245 Methods of application
2451 General The mixed resin may be applied by hand or b pray c1epoition The operation must b completed within the gel time of th y tern and tbe laminat fully cOI1olidated to achi v the phy ieal properties pecified
2452 Hand lay-up The duct surface i coated by hand with resin Llsing a brush and a mar of gla fibp orked in until full consolidation achieved Th proc is repeated untiJ th requird thicknes i obtained
2453 Spray depo Won The duct surface is coated WiUl re in by spray gun with the chopped glass roving added through a separate nozzle The full thickne i obtain d in layer with con olidation of each layer by hand roller
246 Construction
2461 General M ini mum COllst ructional requireshyments are pe itied ill Tabl 10 for rectangular and Table 1J for circular dUClS
2462 Joints and stiffeners Fig 29 30 31 32 amp 33 hoI TOSS
joint and tiffener for reinforced UPVC and PBPP duct
247 Worki g practices The fabrication of ductwork pecifiecl ill thi document i not affected by the addition of GRP
29
DW154 SfJcdJicatiOt for Plastics Ductwork
Table 10 Minimum constructional requirements shy
Longer Side Minimum Sheet Thicknes and
GRP Reinforcement
UPVC FBIPP 1 2 3
mm mm mm Up to 1000 3 plus 3 plus
06 kgm2 06 kgOIl GRP GRP
1001 to 2250 45 plus 3 plus 06 kgm 12 kgm
GRP GRP
2251 to 3000 45 plus 6 plus 12 kgm 12 kgm
GRP GRP
Cross Joints
UPVCFBPP 4
mm socket amp spigot
as Fig 30 or flanged as Fig 29
75 x 9 flange welded on both sides as Fig 29
75 x 9 tlange welded on both sides as Fig 29
rectangular GRP reinforced ducts
SlifTeners Maximum Spacing Between
JointsSljffeners UPVCIFBIPP UPVCFBPP
5 6 mm mm
75 x 9 flat 800 as Fig 31 or
50 x 50 x 5 plastic or MS inverted angle as Fig 32
or tormer as Fig 33
75 x 9 flat 600 as Fig 31 or
50 x 50 x 5 plastic or MS inverted angle as Fig 32
or former as Fig 33
75 x 9 flat 600+shyas Fig 31 or 50 x 50 x 5 plastic
or MS inverted angle as Fig 32
or former as Fig 33
Note 1 On rectangular duct up to 400 mm longer side no stiffeners are required 2 Applies to Tables 10 amp I I For COlJstructional operating temperature limits refer to Part 2 clause 5A 3 Tables 10 amp II apply to all pres ure classes up lo ]500 Pa
Table 11
Diameter
1 III
lJp to 1000
1001 to 1750
1751 to 2500
Minimum Sheet Thickness and
GRP Reinforcement
UPVC FBPP 2 3
mm mm 3 plus 3 plus
06 kgm 06 kgm GRP GRP
45 plus 3 plus 06 kgm2 18 kgm
GRP GRP
6 plus 6 plus 12 kglm2 18 kgm1
GRP GRP
Cross Joints
UPVCFBPP 4 III
socket amp spigot as Fig 30 or flaoged as Fig 29
75 x 9 flange welded on both sides as Fig 29
75 x 9 flange welded 00
both sides as Fi 29
inforced ducts
Maximum Spacing Between
JointsStiffeners UPVCIFBPP
6 mm 2400
800
600
Stiffencrs
UPVCFBPP 5
mm 50 x 9 flat as Fig 31
75 x 9 flat as Fig 31 or former as Fig 33 75 x 9 tlat as Fig 31 or t()rmer as Fi 33
ote On extruded tube tip to 600mm diameter no stiffenergt are required
30
DW154 Specificatioll for Plastics Ductwork
G - Cross joints and tiffeners
Fig 29 Flange Joint Fig32 Stiffener shy inverted angle
M artiPfCuQkbdd erttpObri) Wl111 RP tlddtlt
_- GRPloliu] lh~
Fig 30 Socket and spigot joint Fig33 Stiffener shy use of former
Fig 31 Stiffener Flat
I Pv FlPP ~ ~lmJaDUA1) d
OMrlQ rrnall 1( tQlS
25 STANDARD COMPONENT DRAWINGS AND ABBREVIATIONS
251 The illustrations in this section not only highlight where applicable geometric limjtations for the de ign and manufacture or ductwork components but also recommend
standard drawing representation terminology and abbreviations for both duetwork components and some of the more commonly used ancillaryplant items
252 Designers and surveyors should note that bills of quantities should provide a full description
3)
---
v
DW154 Spcc(fim(ml for Plastics Ductwork
Fig 34 Linear Thermal Expansion
u c 0 N ro 0)
b 0)
S
sect0
5 oS cl) 0)
~
on ~ ltl
c U
-30 -20 -10 0 10 20 30 40 50 60 70 80 90 TEMPRATURE C
~ V
-
~~c_ ~
~V
V ~
-7 ~
-- ~V ----
v
-6
+14
+12
+10
+8
+6
+4
+2
0
-2
--4
ig 35 Typical Design Stress tor UPVC and P
7
6
r shy 5E
-c E----0 4t) VJ 0)
ci5 0Jl 3
~
0)
Cl
2
1
o
UPVC
1
000
1
1
pp
- r-- shy r----- shy - t--shy I
__0
-30 -20 -10 0 10 20 30 40 50 60 70 80 90 TEMPERATURE C C
Note Figso 14 amp 35 shaded area refers to GRP reinforced duct
32
DW154 Speciicfltirm for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - REC ~NGULAR
Splilt~r Posilion W-mm pliucr
A B c 40]--QOO 1 W - -
601-1000 1 W4 Wf2 -
1001-1800 3 WI W3 W2
FIG DRAWING DETAfiS
tU]36 ATI Straight Duct with socket and spigol joint
rn [037 Straight Duct with flanged joints
[I []38 Straight Duct with flanged joints
rkJ Short Radius Bend
39 Applies to any augl and for duct up to 400 n11n wide
Minimum (I1m31 radills = 100 mm
Medium Radius Bend (a illustrated)
[kJ Applies to any angle
40 Long Radiu Bend Similar but radius = W
Throlll radius = W2 Applies to any angle
- Short Radius Bend with plitlers
I -shy -shy u co - t lt Li--_ 41 t 0 ~ I I I
~ I
L 1W
Minimum waal radius = 100 mm Splitters not required in bend angle less than 45deg
42 QJ1 Square Bend with turning vanes ij
3
DW154 SP(L~ficatioll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - RECTANGULAR
FIG DRAWl G DETADS
43
~
I v
L L Radius Tee with internal deflectors
44
~ Radiussed Twin Bend
45
Imiddot
er Swept Branch
46 U-
Sqoare Tee with Turning Vanes
47
~ f
Breeches Piece
48 0 y l Piece
34
DW154 Specificatioll for Plastics Ductwork
STANDARD COMPONENT RAWINGS - ECTANGULAR
55
54
51
50
53
52
49
FIG
~MX
RAWlNG
DmiddotMAX
EfjMAX
Minimum throat rndius = 100 mm
Rectangular shy Round Transformatioll
Eccentric Taper 225deg max in either plane Spliller are required for angles greater than 225deg and hould bi eet the angle between any side and duct centreline
DETATLS
Angled Offset
OUset Taper Splitters are required for angle greater than 22 0
and shoold bi eet the angl between any side and dUCI centrelinc
Mitred Offset
Concentrk Taper 2250 max in ither plane SpUtters are required for angle greater than 225deg and should bisect the angle between any side and duel c ntreline
Radiussed Offset
35
DW154 Splcilcuthm for Plastics Ductwork
STANDARD COMPONENT DRAWINGS ~ RECTANGU AR
Branch ducl DimCllsions widlh (W) (A)
urnl mm up lO 200 75
300 100 400 125 600 150
Ocr 600 200
FIG DRAWlNG DETAILS
56 poundplusmni~~ Rectan~lar - Flat Oval Transformation
57 [ Square Branch
58 er Angled Branch
Branch dUCI Dimensions wfdth (W) (A)
[- mm mm59 3shy Shoe Branch Up (0 200 75
--shy AIshy + 300 100
400 125
450 MAX 600 150
Over 600 200
Branch duct DimensIOn
rP X width (W) A)
60 - 1--shy _
~ mm mm
Bell Mouth Branch pto 200 75 300 100 t 400 125
600 150 Over 600 200
0=0 61 -
~ Bell Mouth
- shy T 4-5deg M x
--I 1-shy
TJ
62 X I ] I
Tele-scopic Joint I Illustrated with flangeL
X63
SBD Single Bladed Damper
36
---
DW154 Spedicatioll for Plastics Ductwork
STANDARD OMPONENT DRAWINGS - RECTANGULAR
DRAWING DETAILSFIG
64 on-Return DamperNRD shyshy
shyXbull
Multi-Leaf Damper Can be piggoted or flanged oppo cd or parallel blade
Alternative controls areshy
q p [gtshy
J HD65 Hand
~MD otori ed
PO Pneumalic
L-lt
l 13G 66 Blast Gate DamperX X
FireSmoke DampersSleeves
211r Ratinggtshy----
L_-
---
----
r----
Ir-- shy
IL- _-l
2hr
With i tallation frame
67 41 r Rating
4hr
Smoke damper SD
Intumc cent Sleeve L-d
37
DW154 Specijicutiolt for Plastics Ductwork
FIG
68
69
70
71
STANDARD COMPONET DRAWINGS shy REC ANGULAR
DRAVING DETAILS
gtshy Access Openings
AP 6 Access Panel - Rerno able
w [ ~ Access Door - Hinged
I ~le Inspection Cover
le -I reg -lt
~X X Flexible Connection
~ Drop Cheeked Radiussed Twin Bend
U Drop Cheek Bend
I
72 Air Flow SymbolX
38
DW154 Specifim[ioll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - ECTANGULAR
FIG DRAWING DETAILS
73
74
75
76
77
Q
Q
rp---t
~
V- I Ir---I
JL --11
THE ABOVE DETAILS TYPICAL PLENUM
Air Terminal Plenums
Plenum with side connection
Plenum with top connection
Cover plate with connection
Special plenum with connection
elescopic conn ction in direction of air flow
39
DW154 SpecijicotiOll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG
78
79
80
81
DRAWING
-23~---pound3-(MALE) (FEMAJE)
-t=j--_j(--d-shy
--L
~ THROAT RADI S= D AS T NDARD
e ~
THROAT Rjf)lU = D A MU)
DETAILS
Straight Duct With male and female connectors
Straight Duct With flange joint and slip joint
Bend MouldedIFormed Applies to any angle ego 30deg45deg60deg90deg Medium radius bend as illustrated Long radius similar but throat radius 0
Segmented Bend 90deg four section minjmum as illustrated
Other Angles 60deg = 3 sections 45deg = 3 sections 30deg = 2 sections
I
i
40 shy
DW154 Speciicafinll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG DRAWING DETAlLS
82 Segmented Twin Bend Radius = D2 max
May also be fabricated from tube
83 Equal Tee MouldedIFormed
84 -~ 1in Bend MouldedIFormed
85 Taper Concentric 1 0 as iUu trated Eccentric 30deg iJJcLuded angle
86 Short Taper
41
DW154 SpcUicatol1 for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG DRAWING DETAILS
87 30 max Offset
Angle Branch
Bran h dUCI Dimcnsions dia (D) lA)
Shoe Branch mm mm 88 Cl
Off rectanguJur Up 10 200 75 lOO 10 400 125
- 00 150 Over 600 200
Bl1IllCh duct DimenlOns din (D) (A
~-$a-Conical Branch mm mm
89 Also acceptable with Up 10 200 r
full conical surface 300 10
400 125
END VrE -shy 600 150 Over 600 200
90
m 75
100 12 150 200
mm Up to 200
_ 300 400
600 Over 600
iUtred Branch
Shoe Branch
J-L----U ~ Bell oulh Branch
ENDV1EW
93
92
91
42
DW154 Specificatiol for Plastics Ductwork
STANDARD OMPONENT DRAWINGS - CIRCULAR
FIG
94
DRAW G
I
~ 30deg 090deg
Breeches Piece
DETAILS
95 amp-----~ Blank End
~-----p Multi-Leaf Damper Can be piggolcd or fianged opposed or parallel blade
Alternative controls areshyri=-+- L-T~
I
---
LT~
I r- -
-+1
J HO Hand96
bMD Molori cd
PD Pneumatic
tl-shy bull
Single Bladed Damper 97 ~ saD
on-Return Damper Vertical application only 98 m~D
43
DW154 Sf1tcificatioll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG
99
100
101
102
DRAWING
$ I-
2hr
1 4hr
SD
~v I I
CO TINENTAL COWL
DETAILS
Iris Damper
Fi reS moke Dam persSleeves
2hr Ratillg
With installation frame
4br Rating
Smoke damper
Intumescent Sleeve
Access Openings
Access panel - removable
Access door shy hinged
fnspection cover
Discharge Continental Cowl
44
DW154 Sp(Cii(ltJll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
DRAWINGltIC DETAns
-
I
I
~
I I I High Velocity Discharge Terminal 103 I
I
I I
J I I 1 ~--
Offset Stack Discbarge Terminal 104 1
~ I e --(-
I
N
I
I
I~
I I Vertical Oischarge with Weather Cowl 105 I
--1--1 I
I
GAPI I
RTl AL DISC) lARGE WITH W ATIIER COWL
45
DW154 SpecUicatoll for Plastics Ductwork
STANDARD COMPONE T DRAWINGS - PLA TEQUIPMENTIMISCELLANEOU
FIG DRAWING DETAILS
106 ~~~ Rectangular Attenuator
107 ~- Circular Attenuator
108
~ Beod Attenuator
109 J ~(f) Heating Coil
110 J ftte Cooling Coil
III Jc[ Electric Heating Coil
112 X F
Humidifier
113 [H XX Axial Fan
114 ~fB1famp Noo-standard Ductwork Cross hntchillg (of any separate type) indicates by reference to a key any non DVil54 ductwork system
115 2llIIIIJIIIIIll Flexible Ductwork
46
DW154 SJeCUicll(iol1 for Plastics Ductwork
TABLE 12 - STANDARD ABBREVIAT ONS
ABBREVIATION FLL
AD Acces Door
AFF Axial Flow Fan
AHU Air Handling nit
All Aluminium
AP Acess Panel
AT Attenuator
AV Air enninal Unit
BE 81ank nd
BQ Blast ate Damper
CC Cooling Coil
CF Centrifugal Fan
CTA Cross alk Attenuator
CVU Constant Volume Unit
DP Drain Point
EEC Electric Heating Coil
El Expansion Joint
FAl Fresh Air Inlet
FA From Above
FB From Belo
fBPP Fabric Backed Polypropyl-ne Sheet
Flexle Flexible Connection
lexfD Flexible Du t
C False Ceiling CO an oil Unit
fD Fire Damper
FFL Finished Floor Level
FJ Flanged Joint
FOAM Rigid Polyurethane Self xtinguishing Foam
FOB Flat on Bottom
FOT Flat on Top
GAM Galvanised after ManufacttrJc
GRP Glass Reinforced Plastic
GSS Galvanised Sheet Steel
HC Heating oil
HD and controlled Damper
HH Hand Hole
HL High Level
HVD High Velocity Discharge
IC Inspection Cover
ID lri Damper
IFS Intumescent Fircleevc
47
DW154 Specification for Plastics Ductwork
TABLE 12 - STANDAR ABBREVIATION CONTINUED
ABBREVIATION
IU
L
tv1D
MS
NRD NTS
OBO
OE
PHD
PD
PP
PP
PRD
PVC
RFC
RSC
R
SBO
SO
S1 TST
SSL
TA
TB
TO TJ
TP
TV
TV
OS
UPVC
S
V
VAV
50 RSA
FULL
Induction Unit
Low Level
Motor controlled Damper
Mjld Steel
on Return Damper
at to cale
Opposed Blade Damper
Open End
Parallel Blade Damper
Pneumatic controlled Damper
Polypropylene
Self xtinguishing Polypropylene
Pressure Relief Damper
Polyvinyl Chloride
Rolled Form Chamlel
Rolled Steel Channel
R fUnit
Singl Blade Damper
Smoke Damper
Slip Joint
Stainl t el
tructural Slab Level
To Ab vc
To Blow
Top Down (In Direction of Flow)
Telescopic Joint
Test Point
TU111iog Vane
Top Up (In Direction of Flo )
Voles Otherwise Stated
Unpl3sticisecl Polyvinyl Chloride
Underside
Ultra Violet Light
Variable Air Volume
Rolled Steel Angle (Vith Size)
48
DW154 SJeriiflllioll for Plastics Ductwork
A2 DUCT PRESSUREAPPE DXA Ductwork con truct d to DWIl54 will bebullbullbullbullbullbullbullbullbullbullbullbullbullbull
Air Leakage From Ductwork To be read in conjunction with DW143 A practical guide to Ductwork Leakage Testing
CAUTION As highlighted ill both this docul1lenr and DW14 I lot ellough emphasis can be placed 01 the fact that except for high pressure class C the much more stringent ductwork constructional standard brolght about b the general acceptance of DW154 have irtlally negated the requirement for leakage-testing It is essential lO realise lhat except where it is mandatory this doclllllelll is nOl an endors ~lIlent of the rourine testing of ducts bllt purely a guide to outline the procedures for cononnity with the air leakage limits ill Table l Where the specified methods of assembly and
A3sealing of dlcls are u ed a vi ual inspection wil ordinarily sl~fll e for ver(iatioll of a well engineered and a ceptahfy airtight COl1strucrioll WHERE NOT MANDATORY DUCT LEAKAGE TESTING IS GENERALLY AN UNJUSTIFIED AND SUBSTANTIAL EXPENSE
A1 INTRODUCTION L akage from ducted air distribution systems is an Lmportant consideration in the design and operation of ventilatjon and air conditioning middotystems A ductviork t)ystem tbat ba limited air leakag within defiucd limits wiH cnsUft
that tile design characteristics of the sytem can be maintained It wilJ also ensure that energy and operatLonal cosb are maintained at optimum levels DucLwork constlucted and Ulstalled in accordance with DW154 should minimise a level of air leakage that it) appropriate to tll operating static air pre sur in tile system
A4However it is recouuised that tbe environment in wtJich middotystems are installed is not always conducive to achieving a predictable level of quality in term of system ajr leakage and it is therefore accepted that designer may sometimes require tlle ystem to be tested in part or in total It should be ecogni ed that the testing of duct systems add a ignificant cost to the installation and incur some extra tjm within the programme (Se 47 and 64 re mandatory te-sting)
manufactured to a structural standard that is compatible with the system operating pressure There are three classes of duct con truction to eorre pond with the three pre ure clas meations Class A Lo pressure ducts suita le for a maximum positive operating pressure of 500 Pascal and a maximum negative pressure of -500 Pascals Class B IVledium pressure ductmiddot suitable for a rnaxilnuJJl positive operafjn o pressure of 1000 Pascals and a maxllnum negative pre sure of -750 Pa cal Class C High pre sure ducts suitable for a maximum po ilive operating pressur of 2000 Pa cals and a maximum negativ pres ur of -750 Paltcals
LEAKAGE FROM DUCTWORK Leakao-e front pia tic air ducts occur at the joint~ and is therefore proportional to the total surface area orthe du twork in th system Tb level of leakage i imilarly related to tIle air pres ure in th du t system and whilst there LS n precis formula for calculating the level of air los it i generally accepted that leakage will increase in proportjon to pressure to rbe pOvver of 065 The effect of air leakage from high pressure velocit ductwork is critical tn terms of system perfomlan dege energy consumption and the risk of high frequency noise as ociated with leakage These problems are le critical with medium pressure 10 ity systems but should be con idered Low pres mevelocity ducts present the lowe~t
ri k in tenn of tbe effect of leakage on the operation of the s stern
SYSTEM LEAKAGE LOSS As there i no di ct relatLonship between th volume of air conv yed and the surface area f the ductwork sy tern required to match the building configuratmn it is difficult to express air leakage a a percentage of total air volume Similarly the operating pressure will vary throughollt lh 3 system and a leakage is related to pre me the calculations ar comple However it is generally ac epted tbat in typical good quaJjty systems the leakage from
49
DW154 Specificatioll for Plastics Ductwork
each class of duct llnd r operating condition will be io the region of CIa S A low pressure 6 Clas B medium pres un 3 Clas C high pressure 2
A5 SPECIFYING AIR LEAKAGE TESTING Re peeting both the co -t and programme implications a sociated with te ling du 1 for leakage the designer may for example indicate that a particular system is te ted as follow
a) High pressure ducts - all tested b) Medium pr ssure duets - 10 of the
ductwork shall be s eet d at random and tested
c) Low pre sure - unte ed In any case where a random te t i elected for medium pre sure ductmiddot the followin c1au~e is suggested for inclusion by the de ign r
The designer hall elect at random a maxirnwlI of 10 of the dUCl system to bt tested for air leakage The duct hall be tested af the pressure recommended in Table J3 for the assifi atiol for the ectiol1 of the ductwork that is to be tested The tests shall be carried Ollt as the work proceeds and prior to the application of thermal insulation In the event of test failure of the randomlY selected section the designer shall have The right to select two La1her e tiolls at random for resting Where succes ive failures are identified there shall be a Tight to require rhl COl11raCWr 10 apply remedial attention to the complete ductwork system Th contractor shall provide documented eviden e of the calculalions used to arrive (1
the allowable 10 I for the section to be tested and the client or his agent shall willess and sign the results of the test
able 13 Air leakage rates
Maximum leakage of duct work Static
prcssUft Low-pressure edium-prc-sure I Iigh-prebull me diJfercntial Class A Class B Class C
1 2 J 4 Pa Litres per second per quare metre of surface area 100 054 018 ZOO 084 028 300 110 037 400 132 044 500 153 051 600 058 019 700 064 021 800 069 023 900 075 025
1000 080 027 1100 1200 1300 1400 1500
029 030 032 033 035
1600 1700 1800 1900 2000
036 038 039 040 042
Note Recommend d mean test presures are highlighted iD bold type with the actual selection being left to tll test operator
50
DW154 Sfeeiieaioll for Plastics Ductwork
A9
A10
and air leakage classification for the y em under test
DESIGNERS CALCULATIONS The designer can middotaJculate with reasonable accuracy the predicted total loss from a ystem by
a) Calculating the operatin presure in each ection of the sy tern
b) Calculating the surface area of the ductwork in each correspondin pre lire s ction
c) Calulating the allowabl~ los at the operating pressure for each ection of the system (see table 13 for allowable leakage figures)
VARIABLE PRESSUR S IN SYSTEMS De igner can achieve significant co t saving by matchina operating pressures throughout the system to constmctional standard and appropriate air leakage testing eO the practice of specifying construction tandards for whole duct sy tems based on fan discharge pre sure may incur unnece sary costs on a project For example ome large sy terns ould well be classiC ed for I akage limits as follows
Plant room risers CJas C Main floor distriblltJou CIa B Low pre sure outlets Cla A
A6 SPECIAL CASES There may be ~itLlations on a project where circumstance dictate thal pecial consideration be given to containing air loss s eg a long mn of duclwork may incur a di -proportjonate level of air 10 s In ca es such as thi example the designer can specify an improved tandard of airtighmess ie 80 of alJo~able 10 s for la B Ju ts The designer sbould not specif a CIa C t sI at CIa s C pressure for a CIa s B ducl
A7 SUGG S ED RANGE OF TES ING
A8 TESTING OF PLANT ITEMS Items of inline pJant (eg Fig 106 to 115) will not normaUy be included in an air I akage test The dllctwork contractor may indud such itelllS in tbe te t jf rh quipm ot has a certificate of COnfOlnlity for Ihe pres ure clas
bull High pressure duct bull Medium pre sure ducts bull Low pre sur ducts bull Exposed extract syst ID bull Ceiling void extract
systems bull Secondary ducts from
VAV or fan coil units bull Flexjble duct bull Final connections and
branches to grille and diffusers
100 test See A5 Untested UDt sted
Untested
Untested Untested
Untested
SI
i
DW154 SJecijicafion for Plastics Ductwork
ig 116 Permitted leakage at various pressures
Leakage in litres per second per square metre duct surface area
Vgt
o ltgt 0 ltgt N
ltgt Cgt
0 0 cc
0 0
~
g =
g ~
c 0
J
ltgt 0 I
~ ] tn
ltgt ltgt
In ol
~ 0 ~ 8 ~
~
c ltgt ltgt
~ CJ
~ ~ ~ ~ 8
0shyij
~ ~ ~ t
ltgt ltgt 00
l
~
~ Q
c C
~ rshy
e ltgt
I 1
I Cgt ltgtv
c Co ~
~~ ~ 10
I
0 Cgt
fJshyq 410 ) 1 ltgt
ltgt N
~ shy ltgt ltgt
~ I 1
c
52
DW154 Specificatio for Plastics Ductwork
Example of a completed test sheet Test No
General
Name of job N~ jC43Pt(r2lef Building Repound ~(~~0
Part 1 - Physical details
a Section of duct work to be tested ~(diffPIfff~el1f3rd Floor
b Drawing Number g91~~ c ssure aSSJ L atlOn V~Jl~IRfYgtg~~lPre Cl T Class C
d Test static pressure -(9 raErq~ ~~~~-~~J~~~ ~~ ~~~~ll
Leakaoe factor 9~-tre3$ecMz I OM REFTOTABLE 13)e b bullbullbullbullbullbullbull
f Surface area of duct under test Q~tJJItetre$ CPROMCALCU TIO BELOW)bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull ampampamp bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull
g ]Vlaxi mum permitted leakage -~ (~i~~0 ~~r~~ ~~~l-~-11~ ~~~Q
Part 2 - Test particulars
a Duct static pressure reading 9QFt~q~ ~ middot~~~1 ~~
b Manufacturer and type of liow measuring d vice (-~~~cJ~Y-9Q7EYg c Range of measurement of now measuring device QtP)OQ~(e~~~0I~~~~1~I~ ~~~~~~W~
d Reading of flm measurin o device pmiddot IFROM RIO)ftscag ~
I (DERlVED [ROM CHART SUPPUED WITH RIG US 0 ud)1e Interpreted air flow leakage rate ~(~~~f~~~ (~l~~~~~~~~~~~~~~~~~I
f Duration ~~~~~norn~allY l~ lnil1Ut~~d~~~ it1~ W~ Date of test ~(lITled ut by Wltll s ed by ~ ~
(~lJ MIJLrr) (Si~rrfltJUYJ
Printed Name 1~g0f~ Printed Name ~~Y~9~ and Company 7jl~~~~~( UJd CompanY AB COII$Itallt8
Width and depth or diameter
Periphery ength Area
millimetreS millimetres metre qL1are metre
800 x 750 3100 1755 5440
600 x 650 2500 557 1193
300 x 300 1200 120 144
305 din 958 700 670
250 dia 785 450 353
TOTAL 8000
53
DW154 Specijilarion for Plastics Ductwork
pA XB
Guida ce No es For he ransport Handling and
Storage of uctwork
avoid damage to adjacent duct panels In somc ca es particularly on con acts calling f r repetitive sizes the use of timber jigs and spacers may be justified Where reduced bulk and greater protection are major factor such as consignments for export transporting ductwork in L shape sections may justify the increa ed ite as embly co ts
It is recommended that before a contract is finalised that consideration is given to the subject of site acces material handling and storage as tbcy havgt a strong influence on the cost efficiency of the overall activity of ductwOlk installation
B3 Handling To minilnise th risk of damage duct sections should be clearly identified and deliveries to site should be closely linked to the installation programme so as to avoid accumulation of
B1 Storage and Handling of Ra Material Material should be stored in suitably designed racking out of direct unJight Where possible the e racks should be metal to earth Edges of cut she t may be harp and protective gloves are advised Wearing teel toe-capped boots is recommended Most pIa tic sheet is manufactured with smootb mfaces andor is suppLied with protective coating Care must be taken to prevent accidental lippag of stacked materials Beiuoshy good electrical insulators the movement of stock unless earthed will allow the build up of stati All stock shapes are chemically stable at normal temperature Whil t some raw materials used in their manufacture may themselves pre ent a toxic hazard once incorporated into the lOck bape they no long r constitute such a hazard and no dermatitic bazard are known nor are any
unfiJied ductwork and minimise double handling It is important to recognise that ductwork panels joint and corners arc susceptible to damage and care must be taken wheu band ling such material through a site During handling individual item of duct work may be liable to light cross sectional deformation until thev become an integral pan of a completed ductwork system Whilst this may temporarily detract from its intended appearance thi deformation will not have any detrimental effect on the functionality of the finally a semblecl system Installation of duct work and asociated plant items ill illevitably involve manual handUng The responsibi Iiry of employers and employees to a ses the risk of personal injury during mallual handling operations is et out in the HS E publication L23 Guidance on Manual Handling Regulations 1992
environmental problems expected 84 Site storage
B2 fransport Large capacity vehicles with high-sided open or closed-top bodies are tlle mo t suitable for the transport of dllctwork Careful consideration should be given to the
Adequate floor space IDust be provided within tbe building for the site storage of ductvork Such storage shalt make due allowance for thc stOf(ne of ductwork in stacks such that access ~ egt
between them is of sufficient width to pennil the removal of item without interference to
unloading of transport on sit a not all siJes b n fit from the material handlino- and access facilities that exi [ in a manufacturing workshop such as crane- fork-lifts or loading bay Site handJiog facilities along with
adjoining sta ks Ductvork components should be positioned so a to avoid crushing Ductwork of small panel size may be stored horizontally however care should be exercised to ensure that tack sizes are limited 10 within
ehicular acce s restrictions may itilluence the type and ize of transport to be uWised
engtlls of ductwork should be positioned 0
the tmctural strength of the duct sections to prevent distortion of the lower sections within the stack
as to avoid crushing Lengths Witll projections such as branches and bends i1anges girths damper quadrauL should be loaded so as to
54
DW154 S1tciic(ltioll for Plastics Ductwork
85 Internal cleanliness of new ductwork The site storage of ductwork introduces the important cODsideration of maintaining the internal cleanliness of the ductwork R feren e should be made to HVCA documentshybull DWffM2 Guide to Good Practice - internal
Cleanliness of New Ductwork Installations If the above conditioDs can not be satisfied consideration should be given by tJle designer to amending the specification to include for Po t Installation Cleaning as covered by tJ1C HVCA documentshybull TRJ17 Guide to Good Practic - Cleanliness
of Ventilation Systems
APPE DIXC
Fi e Retardant inishes C1 Improvement in the fire retardancy of plastic
ducts can be achieved to varying degrees and is wholly dependent llPOll the surface coating laminating resin selected and construction specification adopted In some instances smoke emission is coILSidered equaUy with other speci fication requirernen ts of the materials resistance to ignition and bumjng It is therefore important for design rs to establ ish the clients and officers detailed requirements and not rely on a tbird party interpretation of fire resisting or fire retardant Where possible the specification should refer dir etly to compliance with a British or European Standard identifying the specific sections applicable There are various types of resin and mat rcLnforcements that can achieve a Class 1 surface spread of flame ratin o when tested according to BS476 Part 7 (1987) This test puts materials illto Class I - 4 in descending order of perfoDllance according to the rat and extent of flame spread over their surfac under standard beating conditions Materials should also be tested for flre propagarion to BS476 Part 6 (1989) Tbi tesr measures the amount and rate of heat evolved by the material when subjected to standard heating
conditions Test results are given as an index of Perfonnance (i) whicb is based on three sub indices (iJ (i1) (h) The higher the value of the Index of Performance (i) the greater is the material s contribution to fire growth The higher the value of the sub-index 0) rhe greater the ease of ignition aod flame spread The highest product performance classification as defined in Approved Document B of the Building Regulations is Class O This is acLlieved if a material surface of a composite ploduct i~ either a) composed throughout of materials of
limited combustibility or b) a Class I material which has a tlre
propagation index (i) of not more than 12 and sub-index (i l ) of nor more than 6
01 J Class 0 is not a cla$sif1cation identified in any British Standard test
There are resin system reported to be classified to Class O when tested to BS476 Pcl1S 6 and 7 however designers need to ensure that such sysrems can be applied to their proposed design In propriety resinmat system available the fabrication techniques and COITect application are critical to the integrity of the reinforcing and clas ificatiol1 For example in some systems the u e of a non-fire retardant gelcont on a fire retardant substrate would reduce the classification For further information see HVCA publication DW144 Appendix D
55
DW154 SplCijiClIliol1 for Plastics Ductwork
x Guidance otes For nspectmiddoton Servicing a d
Clean-ng Access Openings
D1 GE ERAL This appendix highlight in ummary fOI111
the acce considerations that hould be made by the design r iD terms of inspection servicing and cleaning Having considered the seop and the design of the dUCI work system relative to the guidelines outlined below the designer should clearly indicate which levels of acces should be incorporated into the manufacture of a new duct work system (See Table 14 and Note I b low it
D2 DESIGN CONSIDERATIONS
D21 In ptction and servicing requireshyments are set out in Section 15 of Lhis specification
D22 Cleaning requirements are set out in the HVCA pubUcation TRl7 Guide to Good Practice Clean Lines of Ventilation Systems and the guide tates The precise location ize and
type of access would be dependent on the type of ductwork cleaning inspection and te ting metbods to b adopted Care protection and standards of cleanliness prior LO cOlllmisionin o
are set out in th AV A publication DWITM2 Guide to Good Practice Internal Cleanliness of New Ductwork Installations and th guide state Wh re specific limits of cleanliness are required ductwork sball be cleaned after installation by a spcialist cleaning contractor It will b in the interests of tht desioner botb financially and practically to cunsider employing a specialist c1eauing contractor at tbe
outset of a contract to internally clean newly installed ductwork prior to bandover This approach would reali e the following benefit shyi) Tb actual numb r of cleaning
access panels could be detennined to suit the method of cleaning to be adopted (This may be 1 s than the maximum requiremen listed under Lev 13 of Table 14)
ii) Clear directions could b given to the ductwork contractor as to tJle size and location of cleaning access panels that are required to be fitted during the mauushyfaclunng pro s
iii) The specialist cleaning operation prior to commi ioning vould enable the cleaning contractor to verify the practical acee requirement for the future cleaning operation associated -vitb a regular maintenance programme
iv) A specialist cleaning operation prior to commissioning would allow the designer to omit from the speeilicatiolJ the DWrrM2 requirem nt for factory sealing protection wipe downs and capping-off
v) Specialist Ieall ill 0 to the measurable standard defin d in TR17 will allow an objective definition of cleanline to be achieved
Car ful consideration must be gIven by the designer to the practl aJ problems associated witb the manufacture and fitting of suitably si Led access panel on small cross section duct and on the circular faces of rouod and flat oval ducts in particular
D23 Special con ideration must be given by the de igner to the practical problems associated with gaining personnel access to heavily congested ceiling areas and multi-la red du twork systems This approach would avoid
56
DW154 Spfciication for Plastics Ductwork
the possibility of access panels being D3 ACCESS 0 IN-LINE EQUIPMENT incorporated into a ductwork system at the This appendix unly covers acc il1spection manufacturing stage that were later found in through the ductwork body adjacent to an item practice to be inaccessible for either ervicing of in-line equipment and not openings in the or cleaning activities equipment itself
able 14 Acce requirements for inspection servicing and cleaning
HVCA PUBLICATIO REFE NeE (uidtgt 10 Gund Prartict
Adjace t OW144 Cleanliness orVcnlillltio S~lcr~ fRjJ7
in-line LeyeJ 1 Level 2 Level 3 ite sequipment pcdionSen lcin~ Section d C1eaniJl( SUn(O)lnspc lion Palle ltk~m_n
2011 (minimum OiL Jubje-ct to duct ~zel (ft~ -Panels
Control Da pcrs One (inspection) 203 One 300 mm x 200 mm Both sid Fire Dampers One (sCTjdJl~) 20211 One 300 0101 x 200 mm One side HeatingCooling Coils One (inspedion) 20213 One 300 mm x 200 mm (lIpstream) Both sides Attenuators (rectangular) None required One 300 mm x 200 mm (downstream) Both sides Attenuators (circular) one retluired One 300 mm x 200 mm (downstream) One side Filter Sections One (inspection) 20212 one required Uoth sides Air Turn Vanes None requjred None required Both sides Changes of Direction None required one required One side In-Duct FansDevices One (inspection) 20213 None required Both sides l
1 In the absence of any indication by the designer only Level ) access will be jncorporated into a new ductwork system
2 Tbe panel izes associated with Lev lis I and 3 acee s ar e middottablished by reference to Section 20 of DW144 and Section 2 ofTRll7 respectively
57
DW154 Speclfifatio for Plastics Ductwork
pA XE
B-bliography Included in this Bibliography are technical pUblications which may be of interest (0 ductwork designers fabricators and erectors and to tho e in the heating ventilatlng air conditioning industries generally nquiric should be made of the relevant organisation at the address quoted Since its publication other addresse contained within 0V154 mav have changed and some pubJicalions may have been superseded
HEATING AND VENTILATING CONTRACTORS ASSOCIATION
4 Palace Court London W2 4JG Telephone 020-7229 2488 Fax 020-7727 9268
Orders fo FlY A Publications Old Matlsion House Eamont Bridge Penrith Cumbria CA 10 2BX (Telephone 01768 864771 Fax 01768 86718) Email hvcapoblicationshvwelfarecouk DWn 44 pe ilicatiun for sheet mctal duclwork (Iow- mediulllshy
and high-pressure) 1998) DWIl4 A practical guide to dUGI ork I akage te ting
(revised 2000) DWII54 Specification for plastic~ duct rk DW171 Guide to good Practice for kitchen venlibtion system DW191 Guide to good pracuce glass fibre ductwoJk DwrrMI Acceptance cheme for new products - Redangolar cro
joint classification Guide to good pra tice - Internal cleanliness of new ductwork installations Guide to good practice for the design for the Installation of lire and smoke uampers
J 1Other puhlications
HampV safely guide 5th edition JS2 Tool box talks JS5 Weldlng Safety booklet JSI9 afety facts bo klet Fact sheets 1-24 2nd edition JS2J COSHH manual volume 1 Advice on compliance with the
regulations 1521A CO I-rH manual volume 2 Asses mcnt h ets JS23 Ri k management manual TR3 BrazinltT and bronze welding of copper pipework cUld sheet
(I 976) TR5 Welding of carbon steel pipework (1980)
TR6 Guide to Good Practice for Site Pre sure Testing of Pipework (19 0) Guide to good practice cleanliness of ventilation Ylem
CHARTERED IN TITUTlO OF BUILDING SERVICES E G EERS Delta House 222 Balham High Road London SW12 9BS rTelephone 020-8675 5211 Fax 020-8675 5449) CIBSE Guide Volume A Design Data Volume B In tallatiol1 and quipment Data Volume C Reference Data
CommlssioniJIg Codes These Codes eover the preliminary checkS eUing to work and regulation of vanous catcgories 0 plan The Codes give a guide to design implications Series A Air Distnbution Systems Series B Boiler Plant
ri s C Automatic Conlrol ystems Cr1es R Refrigerating Sy terns
Sene iN Water Distribution Systems
Technkal Memonllda TM 4 Design Notes for the Middle East TM bull Design otes for Ductwork TM 13 Minimi iog lhc Risk of egiounaires Disease
Research Reports RROI95 Ventilation system hygiene - A review of published
infomlatioo on lhe occurrence and ffects of Olltamination Rl~02J95 Air-to-air heal rec v ry RR0395 rnfluen e of HV C on smoke detectors
ATlONAL ENI [ERING SPECIFICATION LfMITED Southgatc hamber 3739 Southgate Street Winchester S023 9EH (Telephone 01962 842058 Fax 01962 R(8982) BUfLDING S RVICES RESEARCH AND [ ORMATION ASSOCIATIO Old Bracknell Lane West Bracknell Berkshire RG 12 4AH (Telephone Brackl1eU (01344) 426511 Fax 01344 487 -7 )
Application Guides AGln4 De tglJing Vana~le Volume middotylans for KOOnl
iir Movement AG1I91 Commissioning of V Sylcms in Buildings 11 6194 Fire Dampers
B) 94 cntiJalion or KitcneTls
AG389 The Commls ionin of Air Systems In Buildmgs AH2192 Commissioning of Bern - A ~ode of Practice TN2417 I Fire Dampec il) Ventilating Ducl
BEATING VENTILATING A AIR CONDITION G MA UFACTURERS ASSOCIATIO (HEVAC) HEVAC Henley Road Medmenham Marlow Buck SU 2ER (Telephone 01491 578674 ox 01491 575024 Emoimiddot infofetacouk)
Publicatjons Air Diffusion Guide Guide to Air Handling Unit Leakage Testing Guide to Good Practice Air Handling Unit Real Room Acoustic ~ st Procedure Specification for the ertiiicatioll ofAir Filters Method of Test for Water Rejection PerfOnTlatce of Louvrcs Subjected 1(1
Simulated Rainfall Test Procedure for Acoustic Loo cs Specification 10 Floor GrilJes - Types Performan e and Method ofTest Specification for the Determination of the Collection Efficiency of SilJ1d
Trap Louvre Domestic Mechwlical Vclltllalion Systems with Heal Recovery Fan Application Guid
~an and Ouctwork Installation Guide Guide to Fan Noise and Vibration
pecification of Requirements for JallJral Smoke and Heal Exhausl Ventilators
pecification for Powered Smoke and Heat Exhaust Ventilators
Specification of Requirements for Smoke Curtains Design Gujue of Smoke Ventilation for Single Storey Lodustrilll Building~
Including those with Mezzanine Floor and IIi Racked Storage Warehou es - Issue 3
Guidance for the Design of Smoke entilation YSlem for Covered and Undergrollnd Car Parks - lssue 1
Application of SOloke Control Equipment and Syst m Guid to Good Practice - Isue J
58
DW154 Sp(C~tiifitiol for Plastics Ductwork
BRITISH STANDARDS INSTIT TION Sales Department 101 P ntooviLle Road London NI 9ND (felephone 020-78 1 78801)
CP 413 1973 Ducts for building ervices
SS 476 Fire tes on building matenals and lruc(ure
Part 4 19 4 Non-combustibility lest or materials
Part 6 I Fire propagation lest for materials
Part 7 1993 Surface spread of tlarnJ tesls for materia
Part 20 1987 Fir resistance of elements of construction
Part 21 1987 Fire r sistlUlce of loadbeanng elements of construction
Part 22 1987 Fhe istallceofllon-loadbearing elemcllts ofconsttuclion Part 23 1987 Contribution of componcnts to the fire resistance 0 a
structure
Part 24t987 Fire resi lance of wl1lilation ductl
SS 5588 nan 919 0 Fire Precautions III thc desIgn and OOSlnJ lion of buildings
S 729 1971 Hot dip galvanized oatiugs (or irOIl aod stcel articles
BS 1449 Steel plate sheet and Irip
Pan 11991 Carbon steel plate heel and strip Part 2 1983 Stainless steel plate sheer and strip
and
B middotENJOI49-2 996 BSEN 10149- 1991)
BSEN 10131 1992
BSEN22063 Sprayed metal coarings 1994 Protection of iron and steel by aluminium and zinc against
atmospheric cOlosion Irotectiotl of iron and ste I against corro ion and oxishydation at elevared temperatures
BS 353 1981 Glossary of lerms relnting to thermal insulation
BS ISO 1479 Self-tapplngscrewsandmetallicdri c crew
B -lSO 7049
1994
B 4800 1989 Painl colour for building purposes B 4848 l0 rolled structural steel sections
Part4 1972 Equal and unequal angles BS 5422 1990 Specification for the use of therm illuating matcriulS
SS 5720 1979 ode of practice for mechanical veutilating and air C 11shy
dirionin bull in building
l3S PR 12814-1 Bend resting for plasric welds
SS PR 12814-2 Tensile testing for plastic welds
SS PR 13067 Appro altesting for plastic welds
BS PR EN I 100-] Vi ual in pection ofplaslic welds
SHEET METAL AND AIR CONDITIONING CONTR-CTORS NATIONAL ASSOCIATION INC (SMACNA) Headquarters 420 I Lafayeue Center Drive Chanlilly Virginia 2051-1209
Mailing Address pa Box 221230 Cbantilly Virginilt120 153-1230
Telephone (703) 803-2980 Fax (703) 803-3732
Accepted IJJdustry Pl3Gtice for Industrial Duct Constnlelion 197 ) i-rchitecmral Sheet kwl Manual ([993)
Comractors Guide lor Modification 10 ooslruerion Colllraets 1993 Ducted Eleclric Heat Guide for ir Handling Ssrerns (1994)
En~rgy ollservatioD Guidelines (1984) Energy Recovery Equipment yslClllS (199l
Fibrou GIns Duct onS1ntClion Standards (1992)
Fire Smoke amp Radiation Damper In tall Guide for HVA Syst ms (1992) Guide t leel Stack 1(95)
HVA Air Duct Leakage Test Manual (19 ) HVA COlllmissioning lvlanual (1994)
H A Duct Construction Standards-Metal amp Flexible (1995) Addendum 01 (Nov 1997)
HVA Duct Systems Inspection Guide (1989)
HVA ySlems-Application (1986) nVAC ByternS-DLlct D ign (1990)
HVi Systems-Testing Adjusting amp Balancing (1993)
indoor Air Quality Manual (1993) tcheu quipment Fabrication Guidelmes (1990)
Managers Guide for elding (1993)
Rectangular Industrial Duct Cons1TUction Standards (19 0) Round Industrial Duct oustmction Standards (1977)
Sei mic Restraint Manual (1991) (wl Appendix E 1993) SMACNA Ma le Index ()fTechnical Publications (1995) Tbennoplnstic Duct CPY ) Construction Manual 1994)
DEPARTME OF THE ENVIRO MENT (Publications Centre) H Stationery Oflice 5 Nine Elms Lane London SWS 5DR
MampEJ 011972 Electrical in tallat1011 in buildings ( ew Editiou)
IampE 0319 Healing hot and cold wat r steam and gas losla1lations for buildings
M amp - No4 1970 Central heating and hot and cold ~ ateT in tallations for
dwelling
M amp ENo100 1971 Mechanical ventilation for building~
ASSOCIATION FOR SPECIALIST FIRE PROTECTlO As ociation House 235 Ash Road AJdershot Hampshire GUl2 4DD
Telephone OJ25221322 Fax 0 J252 333901
lublicalioos Fire Ratcd and moke Outlet Ducrwork An Industry Guide t Design and InSlalla lioll
HEALTH AND SAFETY EXEC TIVE Rose Court 2 Southwark Bridge London SEl 9HS Telephone 020-7717 6000
TWJ THE WELD G TlTUTE Abington Hall Abington Cambridge CB16AL Telepbone 0 J223 89162
Publication DatJ Oil w~ldll1g of lhermopla lics
59
DW154 wciiwlioll for Plastics Ductwork
A -=--DIX
Factors
Specific gravity shy pp = 091 approx UPVC = 14 approx
Some miscellaneous conversion factors
To convert
Length Inches to millimetres Feet to metres
Multiply by
2540 03048
To convert
Millimetres to inches Metres to feet
vIultiply by
003937 3281
Area Square inches to square millimetres 6452 Square millimetres to square inches 000155 Square feet to square metres 00929 Square metres to square feet 10764
Volume Cubic feet to cubic metres Cubic feet to litres Gallons (UK) to litres
002832 2831 4546
Cubic metres to cubic feet Litres to cubic feet Litres to gallons (UK)
35315 00353
022
Mass Ounces to grams Pounds to kiJograms Tons to tonnes
2835 04536
1016
Grams to ounces Kilograms to pounds Tonnes to tons
003527 2205
09842
Volume flow Cubic feet per minute to cubic Cubic metres per second to cubic
metres per second 0000472 feet per minute 2119 Cubic feet per mIDute to litres Litres per second to cubic feet
per second 04719 per minute 2119
Motion Feet per minute to metres per second 000508 Metres per second to feet per minute 197
Pressure Inches water gauge to millibars 2491 Inches wateJ- gauge to pascals (Pa) 2491 I Pa = I ewton per square metre = 10-2 millibars
60
Heating and Ventilating Contractors Association Esca House 34 Palace Court London W2 4JG
Tel 020 7313 4900
e-mail contact Itvcaorguk web site wwwhvcaorguk
Fax 020 7727 9268
DW154 Spedjicfltiotl for Plastics Ductwork
utilised for attacllment to plant or other equipment
1052 Drillings Drjllings shall be placed to permit clearance to tbe extel11al casing and any reinforcement of tbe ductwork for the application of fastening
1053 Fastenings For nonnaJ application bright zinc plated bolts nuts and vashers hall be Llsed in sizes and pitch centres shown in Tabl 3 Where special conditions prevail consideration of other material finishes such as stainless steel bolpounds nuts and washers may be used In all cases gasket materials as Section 825 shaLL be used
106 Expansion joints Wher the configuration of the ductwork does not provide for movement due to temperature change or where such movement is restricted by branches or attachmenL expansion joints should be specified by the designer (See Section 18 FlexibleExpansion joint connections)
It is the re ponsibilir-y of the designer to identify the positions of any necessary expansion joints hased upon design param ters for the individual systems (See Figs 23 to 25 34 amp 35)
Design ote xamples of expansion joints shown in Figs 23 to 25 are not suitable for movement exceeding 30 mm
107 StilJeners
1071 External stiffeners Shall be fitted as specified in Tables 2 amp 10 and Figs 5 amp 6
1072 I temal stiffeners The u e of internal stiffening or bracing shall be acceptable iJ deemed necesary and approved by the designer (See Fig 7)
11 FITTINGS
111 Standardisation of fiuings The terminology and descriptions of rectangular duct fittings a et out in Section 25 are recommended for adoption as standard practice to provide common terms of reference for desi crners quantity surveyor and ductwork contractors and for those using computer in ductwork design and fabrication
Bend are designated as hard or easy and the e terms as used herein have the folJowin o
meanings
Hard signifies rotation in the plane of tb longer side of the cross ection
Easy signiiies rotation in the plane of the shorter side of the cros section
An example iIlu trating these term ] given in Fig 8
Fitting are fabricated by cutting and welding sheet
112 Stiffeners Shall be as 107 and Tables 2 amp 10
113 Splitters Shall be as shown in Fig 41 and welded as 1003
114 ruing vanes Where square bends are required turning vanes as shown in Fig 9 hall be fitted
115 Branches When fitting branch ducts to a main duct care should be taken to ensure that the rigidity- of the duct panel is maintained in terms of tbe sti ffenillg criteria
116 Change shapes Where a change bape is necessary to acconUllOdate the duct and the cross- ectional area is to be maintained the slope haU not exceed 225deg 011 any side (See Figs 52 to 56) Where a change in shape includes a local reduction in duct cras - ectionaJ area the slope should not exceed ISO on any side and tbe reduction in area should not exceed 20 Where tceper angles are necessary due to ile
12
DW154 Spec([icatirJ1l for Plastics Ductwork
restucllOn splitters shall be provided Taper Transformation pieces from circular 10 square pieces reducers and transformation piec s or rectangular shall be made as long a shall be manufactured from the tbickl1 s of p sible and uJe angl ball be uot mor than material specified for the larger size ducl 225 (Fig 55)
loon Pa 1500 Pa
2 3 4 5 6 mm mm mm mm
3 socket amp spigot - - -or tlanged
as Figs 1 2 3 401 to 600 45 flanged 50 x 9 flat 1200 800
50 x 9 flat welded both sides a Fig 3 as Fig 5
601 to 1000 45 flnged 50 x 9 flat 800 600 50 x 9 flat welded both sides as Fig 3 as Fig 5
1001 to 1500 6 anged 75 x 9 flat 600 600 75 x 9 flat welded botb sides as Fig 3 as FieJ 5
or or 70 x 70 x 9 angle 50 x 50 x 5 angle
as Fig 4 welded both sides as Fig 6
N t For constructional operating temp rature limits refer to Part 2 Clause 54
Longer Pitch Bolt Size
Side max 2
mm 1m mm Up to 400 100 8 with washers 401-600 tOO 10 with washers
601middot1000 100 10 with wash rs 1001-1500 100 10 with oycrsized
washer
13
Table 2 inimum con tructional requi ments - rectangUlar nmiddotreinforce UPVC and pp
Joints Sliffeners Maximum spacinOLonger Side MillirnUlll She t between
Thickness Joint~S(iffi ners
mm Up to 400
DW154 SpedflCiltion for Plastics Ductwork
Cross joint - recta gular ducts
Fig 1 Socket and spigot joint (UPVC and PP)
Conlinuou weld joint on sile onlinuou- wcld
CT~r~T2
Fig 3 Flange joint (UPVC and PP)
ontinuou weld
Fig 2 Socket and spigot joint (UPVC only)
Fig 4 Flange joint (UPVC and PP)
S iffeners - rectangular ducts
Fig 5 Flat Fig6 Angle
Oatim wo]
Fig8 Bends - examples of hardTie rod assembly and easy
Hard
Fig7 With spacers Easy
4
DW154 Speci(uariml for Plastics Ductwork
Fig 9 Turning Vanes
HOWl G TYl AL EXAMPLE OF FOCI G
15
Ma vane length shy 615 mm
Example ofbraemg when V1IIle length exeeed max pennined Ahematively two banks of ncs fixmg the centre rail together at ] 50 mm nrrcs
U~_II---- fixed to dnct wall both CDds
bLEVATION
vane
Maximum distance between centrc oflUming vanes should [Jot exceed 60 mm pitch
DW154 SPCCijicllfiull for Plastics Ductwork
practice to provide common terms ofPA T4 reference for designers quantiry urveyor and
Circular Ducts
12 CIRCULAR DUCT SIZES Th duct sizes [n Table 4 have been selected from the ISO and C standard ranges as the 132 preferreod sizes
Table 4 Circular ducts shystandard extruded tube sizes
133 Extruded tube
ISO Standard Sizes (Nominal Diameter) 11
Wan Wall Thickness Thickness
mm mm mm mm 110 500 4022
I25160 600 50 I25200 630 60
225 25 700 60 13425250 800 63
280 900 70 315
23 23 80
355 1000
25 1250 104 400 32 1400 108 450 35
Note The above sizes are subject to normal manufactl1ring tolerances Other size may be available in varying wall Lhicknesses and subject to test and operational pressure
13 CONSTRue ION
13 General Tllis specification covers duct sizes up to a maximum diameter of 1500 mm The minimum constructional requirements for UPVC amp PPPPS un-reinforced ducts sball be as Tables 6 amp 7
ductwork contractors and tho e using computers in ductwork design and fabrication The requirements for circular duct fittings apply throughout the size ranges covered in this specification
Sheet jointing seams Seams shall be joined either by continuous fLiJer rod hot air welding or by fu ion welding Other forms of jointing are not acceptable
Socket and Sl)igot joints Socket and spigot joints shall be formed by purpose made double socket pieces 100 mm long and of the same thickness material as tJJe duct welded into position on each tandard length of duct forming 50 mm deep sockets prepared and ready for final jointing on ite with PVC adhesive andor fill r rod of the same formulation used for fabrication
Flanged joints
1341 Flanges abricated flanges shall be conshy
structed using minimum of 9 mm thick by 50 mm wide material of matching formulation depending on duct size as shown in Tables 6 amp 7 The flange shall be mounted true and square to the duct surfaces and welded OD both sides a 103 and Fig 12
1342 Drilliogs Drilling ball be placed to permit clearance to the external casing and any reinforcement of the ductwork
1343 Fastenings For normal application bright zinc plated bolts nuts and washers hall
16
For srualler diameters preformed fittings are available otberwise fitting are fabricated from segments of duct or sheet welded together
The terminology and description of circular duct tiltings as set Ollt in Section 25 are recommended for adoption as standard
be used in sizes and pitCh centres shown in Table S Wh re special conditions prevail consideration of other material finishes such as stain le steel bolt nuts and wasbers shall be u ed In all ca cs gasket materials as Seciion 825 shall be USed
DW154 Speciliwriml for Plastics Ductwork
135 Stiffeners
1351 External stiffeners Shall be fitted as specified in Tables 67amp 1 I and Fig 13
1352 Internal stiffeners The use of internal stiffening or bracing hall be acceptable if deemed neces ary and appn ved by the designer
f 36 Expansion joints Where the corrfiguration of the ductwork does not provide for movement due to temperature
Cross joints - circular ducts
change or where such movement is restricted by branches or attachments expansion joints should be fitted (See Section 18 Flexible Expansion joint connections)
It is the responsibiLity of the designer to identify the position of any necessary expansion joints based upon design parameters for the individual systems (See Figs 23 24 2534 amp 35)
Design Note Examples of expansion joints shown are not suitable for movement exceeding 30 mm
Fig 10 Socket and spigot joint (UPVC and PP)
ConLinuous weld joim on ite Ontinuous weld
crlr~l
Fig 12 Flange joint (UPVC and PP)
Continllous wcld
boil
Continuous weld or Solvelll cement
Solvelll ccmcnl joim on sile
Fig 11 Socket and spigot joint (UPVC only)
Stiffeners - circular ducts Table 5 Fastening centres shycircular duct flange jointsFig13 Flat
flat conljnlJou~ly welded Diameter Pitch Bolt Size
max
1 2 J 11
1 shy -~
mm mm mm Up to 600 100 8 with washers
601middot1000 100 10 with washers - ---I
1001middot1500 100 10 with oversized washers
1
Minimum offourfixings
17
DW154 Specifiiutiofl for Plastics Ductwork
Table 6 constructional quiremen s - circular unshy inforced U VC
Diameter Minimum Joints Stiffeners Maximum spa ~in r
Sheet between Thickness Jointsl tiffcners
1000 Pa 1500 Pa
1 2 3 4 5 6 UD mm mm mm mm
UO to 600 3 socket amp spigot as Figs 10 11
or fla ged Fig 12
601 to 1000 45 socket amp spigot 50 x 9 flat 2400 2400 as Figs 10 11 welded bo sides
or Oanged as Fig 13 as Fig 12
1001 to 1500 6 Hanged 75 x 9 flat 1200 1200 as Fig 2 welded both ides
as Fig 13
Applies 10 Tables 6 alld 7
Note 1 For constructional operating temperature limit refer to Part 2 luu 54 2 To allow for conicleration or extruded se lions or fabricated component the materia] tllicknes i hawn a nominal
Table 7 Minimu onstrucfional requirements shy circular un-reinforced PPS and
Diameter Minimum Joints Stiffcners Maximum pacio Sheet between
Thickness Join sStiffener 1000 Pa 150n Pa
I 2 3 4 6 mm m m mm
110 to 500 3 socket amp spigot as Fig 10 or flaoged as Fig 12
501 to 750 45 ocket amp spi~ot
as Fi 10 or Uanged as Fig 12
751 to 1000 6 tlanged 50 x 9 Oat UOO 12 0 as Fig 12 welded nth sides
as Fig 13 1 1 to 1250 6 flanged 75 x 9 flat 800shy 800
as Fig 12 welded both sides as Fig 13
1251to~ flangcd 75 x 9 Oat 600 600 as Fig 12 welded both sides
as Fig 13
18
DW154 Sped(icalirm for Plastics Ductwork
PARTS
Hangers an Suppo ts
14 GENERA
141 Supports are an e sentiaJ part of me ductwork system and their supply and in tallation are normally the responsibility of the ductwork contractor The principl s are a I-rvCA publication DWIl44 Part 6 Section 19 and should be read in conjunction with this document
Design Note Designers may pecify specific requirements wbich will supersede guidance given in DW144
142 Rectangular ducts abl 8 give the- minimum requirements for
hanger and supports for un-reinforced ductwork
143 Circular ducts Table 9 gives the minimum requirements for hangers and upports for uD-reinforced ductwork
144 Vertical d cts The design of supports for vertical duct is dictated by site condition and where practical duc hould be upported at 4000 mm interval or where tbey pa s through a floor (but n ver exceeding 4500 mm) see Figs 17 amp J8
145 External ducts Where ducts are external to buildings and may be ubject to wind loading support should be plac d so as to restrain ide tl1ruSt and should allow axial movement as neces ary It is the respon ibility of me de igner to calculate the effect of the particular prevailing condition and to define any special upport requirement
146 Expansion joints Support shall be designed to permit axial movement only and shall e provided on eitl1er ide of expansion joint
I 1shy
I~
mm -Jp to 400
401 to 600 601 to 1000
Table B Hangers and Supports - rectangular horizontal ducts
Hanger Bearer Drop Roll Formed Rod
Long r Side
Cbannel ~-shy ~
---shy
Maximum ~pacing
4 52 3 _ -c Fig 15 - Figs 14 15 16 amp 2J
shy
mmm mmmm 240025 x 25 x 16 40 x 20 x 15 8 240040x20x15 40x 20 x 15 10 240040 x 20 x 1~510 40 x 20 x 15
shy
I
40 x 40 x 15 40 x 40 x 15 24001001 to 1500 I 10
Table 9 Hangers and Supports - circular horizontal ducts
Longer Side Hanoer Split Clips Maximum spacing Drop Roll f-ormed and Wrap-round Rod ~hannel Hang r
2 3 4I Fig 1920 amp 22Fig I
mm mmmm mm mm 25 x 25 x 15 IIp to 355 8 40 x 3- --1-_ 2400
2400
2400 2400
70x 6
40 x 5 SOx 5
40 x 20 x 15 40 x 20 x 15 40 x 40 15
10 10 10
356 to 600 601 to 1000 1001 to 1500
19
DW154 Spccijicutioll for Plastics Ductwork
147 Protection specification Any special coatingpaint Unless otherwise stated all support shall be finishes for protection against hostile manufactured in material as specified in this environments shall be advised by the designer
SUPPORT BEARERS
~ 14 Flg16 Inverted profile
angle I ~lIed steel
channel (alternatives) Fig 15 Profile channel (alternatives)
TYPICmiddotAL VERTICAL DUCT SUPPORTS Flat bar clipStiffening frame Outline ofinsulation stiffening frame or tlanged joint (if applicable) or flanged joint
Stiffening framc or flanged Joint
~~-I ( ee notes 10) I
r--~ -++- ~--4==J===4~---
Fig 17 Vertical rectangular ducts Fig18 Vertical circular ducts
The support bearer which depending on ducti tructural opening size could be either channel or angle section may be ll1ilised in any of the following arrangementsshy
a) To support the underside of a flat bar clip in halves (circular)
b) To support the underidc of either the stiffening frame oftbe flanged joint ofaoy duct section
c) To support either a stiffening frame Or a flanged joint below nsing drop rod srudding
20
DW154 Spediraiml for Plastics Ductwork
Arrangement of bearers and hangers (to be read in conjunction with Table 8 amp 9
wbich list material sizes relative 10 duel izes)
KEY Limits refer to actual duct size - insulation is additional - Typical
attachmentv -Atta hment t strucUlrcI to strucUlrc
I I
I - Flat Bar
I - Drop rod or - utlinc of lllddmg In ulillwn (if
applicable)
Alternative 7 drop rod or rt------------ 1 studdmg q I
I I Rectangular
ii i n 1
Fig 21 Rolled or profiled bearer Limit oncFig 19 Wrap-round hanger Limit 55 DIA
V v Drop rod orAllernaUC 1 1 tudding
drop rod or 1
-- -- 1studding and elded bas 1
I I0 -_
Limit 355 DIA Frg 22 Split clips Limit 1500 DIAFig 20 Flat strap hanger amp split clips
21
DW154 Specification for Plastics Ductwork
6PA deElned in J62 appropriate to the airflow pressure acoustic temperature and corrosion
General
15 ACCESSl SPECTION OPENINGS
151 General These are for inspectionservici ng on 1y
HVCA publication DWIl44 Part 7 - General Section 20 sets out the requirements for access applicable to this specification
152 Cleaningmaintenance Designers shall take specialist advice and then stipulate their requirements for the periodic internal cleaningmaintenance of ductwork and of the consequent need for adequate access for specialist cleaning equipment including the size type and locationfrequency of the actual access openings required
Appendix D sets out guidance notes for the consideration of cleaning access and also makes reference to the HVCA publication TR 17 Guide to Good Practice Cleanliness of Ventilation Systems which covers the su~ject
in greater detail
Note A majority of in tallations in which plastic ductwork is used are considered to have a nigb operational risk potential and provision of access should address this
16 REGULATI G DAMPERS
161 General Balancing dampers and control dampers are elements inserted into an air di tribution system or element of an air distribution sy middottem Balancng dampers permit modification of the air resistance of tbe system and consequently cbanging of the airflow rate Control dampers control tlle airflow rate and may in addition provide low leakage closure of the airflow
The deigner shall specify damper locations taking into consideration that good design practice requires a minimum of five times the diameter or width of the shortest side of uninterrupted flow between plant connections and the damper and select the damper type as
characteristics
1611 Balancing damper To achieve the required distribution of air in the ductwork system at inlets andor outlets for [hi purpose the damper blades are set and Jocked manually in position between fully open and fully closed
1612 Control damper To secure dynamic control of the air now in the ductwork system In thi function the damper will always be power actuated and may require to be modulated between fully open and fully closed and to be capable of taking up any position between these extremes In the fully open position the damper should have a minimum pressure drop In the fully closed position it will not necessarily achieve a complete shut off
162 Types of airflow control dampers Airflow dampers of various types are available for specific purposes as follows
1621 Single - blade dampers Single-blade dampers shall consist of a si ngle pi voted blade cOlllained withjn a casing or section of ductwork The blade shall be adjustable tbmugh a nominal 90 angle by means of a quadrant or similar operating mechanism Where automatic control of the damper is required the spindle shall be extended to enable a powered actllator to be mounted
Single-blade dampers shall have a maximum duct width of 400 nUll and a maximum duct height of 400 mm for rectangular ducts and for circular ducts a maximum diameter of 400 mm
1622 Multi-blade dampers Multi-blade dampers shall consist of a number of pivoted blades contained within a casing The blades shall be
22
DW154 Sedicalirm for Plastics Ductwork
adju table through a nominal 90deg angle simultaneously by intershyconnected linkage or gears connected to a quadrant or similar operating mecbanism Where automatic control of a damper is required a spindle shall be extended to enable a powered achlator to be mounted
There is no restriction on the size of duct in which multi-blade dampers or damper assemblie may be u ed Where dampers are required for blade lengths in excess of 750 mm the blades should be suitably reinforced or supponed 0
individual damper blade should exceed 200 mm in width
1623 Iris dampers Lris dampers shall consist of a nUlllber of radialty interconnected blades which open or close within a casing with duct COlll1cctions The blade shall be simultaneously adjusted by a quadrant or similar operating mechanism
Iris dampers shall be installed as specified by the manufacturers operating and installation instructions where the product is unidirectional with regard to airflow
lris dampers are available for circular ducts only in diameters up to 250 mm (it should be noted that the damper casin i appro)(imately twice the diameter of the duct)
1624 Backdraught dampers Air pressure operated uni-directional rectangular (single or multi-blade) with adapters if fitted to circular ducts
1625 Slide and blast gate dampers A damper [lsed as a shut off facility with an externaJ Lide bousing allowing the blade configuration to be fuJly inserted to fully extended for maxiDlUlll air flow
163 Construction
1631 Materials All products shall be protected against cOHosion as necessary and supplied in a fully finished condition as specified by the designer
1632 Dampers used in low and medium pressure systems The following recommendations apply to dampers forming an integral part of ducrwork with pressure classifications A and B air leakage limits
The dampers shaH be constructed to minimise distortion and prevent jammin in operation Th blade shall be sufficiently rigid to minimise movement when in the locked pOSitiOLl
The blades shall be securely fixed to the operating mechanism All balancing dampers shall have a locking device located on the outsid of the case and shall giv clear indication of the actlwl blad position All penetrations of the duct shall be fitted with suitable seals where necessary
1633 Dampers used in high pressure systems Regulatino- dampers used in duc[work sy tems to pressure cJassification C shall meet tbe construction requireshyments specified in 1631 and 1632 with operating mechanisms out of the air-stream
1634 Proprietary types of damper The use of any specific type of proprietary damper shall be confirmed by the designer In all cases proprietary dampers shall meet the relevant requirements of thi specification
1635 Damper casings Duct damper casings hall be constructed to meet th mllllmum
23
DW154 SpeciJimlioll for Plastics Ductwork
leakage Iim its sp cified for th c1uctwork ystem to which tbey are installed
In order to apply the square metre leakage calculatio as detailed in DW143 A Practical Guide to Ductwork Leakage Testing the reference casing area ball be taken as the perimeter ize of lh damper IDultipli d by the equi alent length of Imetr eg an 800 mm x 400 mm duct damper hall have a surface area for casillg leakag p donnan calculated as follow (2 x 08) + (2 x 04 x I
=24m2 casing area
Other pelforlllance ancl rating test methods for damp f and valves are specified in ISO 5129 and BSIE 1751 and are referenced belm a) Leakage past a closed damper
alve BSIE 1751 b) low ratepre sure requirement
characteri t cs BSIE 1751 c) Operational torque le ring
BSEN 1751 cl) Thermal transfer testing
BSIEN 17 I e) Reg nerated sound power levels
ISO 5129
164 Installation Dampers shall be imaalled in accordance will) any re Ievant ISO EN or British Standard 10 aJ bUT lcling regulation and national code of practice as well as the manufacturers recommendations
17 FIRE DAMPERS AND INT MESCENT SLEEVES
171 General Damper or sleeves arc requiTed on duct y~telll where the designer has -tjpulated the
duct wiU penetrate a fire compartment in the majority of application tbermopla ti ductwork is ugtecl where contamlDated corro ive or otherwise exceptional fumes are concerned it is preferable to use tire damp r which are externalJy mounted ie of the intmnescent operated crush typ
24
72 Fit-e rating The damper assembly should have a fUT
resi tance ratin o equal to that of the fir ban-jer it penetrate and ball be fire tested and rated to the timetemperature curv of B 476 Part 20 and 22
173 Intumescent sleeve At the time of writing this specification qualified test results were available for rectangular dampers and circular dampers up to 55 mm diamet r Manufacture have indicated that they are able t provide speci fications for other size and diameters This infonnation should be confirmed b th de igner Various type are available includino
tho e incorporating ruechanical closing plate and those operated anI by expanded iJllUme c nt media
In all ca es fire damp rs and intnmeBcen leeves shall be supplied and in taUed in
accordance with the manufacturer iJlStructioos and COSHH a essm nt
174 Other types Fire dampers of mious types are availabl for specific purpose~ ee HVCA publication DW144 The de igner should )lot (hat materials for con lt1Jction bould be uitablc for the par1icular application
ALL C SES FIRE DAMPERS AND fNT MESCENT SL _VES SHALL HE S PPLTED AND INSTALLED IN A ORDA CE WITH Tf--IE MANUshyPACTURERS STRUCTTONS AND COSHH ASSESSMENT
18 FLEXIBLEEXPANSION dOINT CONNECTIONS
181 General ploperties Tbe material u ed for flexibleexpan ion iojnt~
mu t meet the design r requirements for temperature air pressllrelfe resistance applicable to pl astic duct sy tem vibration and noi e br akout when incorporated into a jointconnection and shall comply ith lh standard of air-tigbtne specifi cl for the duct work sy tem of which it fOlms part (See Figs 23 24 5 26 27 amp 28 for typical con truclion clelai Is
DW154 SJecilimtol for Plastics Ductwork
Expansion joints
Fig23 Moulded bellows type (rectangular and circular)
Fig24
~F aiblc sleeve
__ liding sleeve
~~~~
Sleeve type (circufar)
Fig 25
AIRFLO
COnlinuou~
weld~
Flexible Iceve
PV A HOWN pp SE BACKING FLATS AS FIG 2
Sliding lee c Co1linuou
weld
Flanged sleeve (rectangular and circular)
25
DW154 Specificatiol for Plastics Ductwork
Flexible con ections
Fig 26 Flexible sleeve with clips (UPVC and PP)
--__ Flexible I eve
I
I
I CODn clioD to plant ~
Band clip
Fig27 Welded flexible sleeve (UPVC only)
Plastic)sed PVC slceve ~-- onll11uo1sly welded
onrreclion to planl ~
Fig28 Flanged flexible connection (UPVC and P )
t sp dally moulded flexible flanged connCClitlll
boil
C)nneclion to plant ~
26
DW154 Specificotiol for Plastics Ductwork
182 LOClt1tion Flexible joint are typicltllly lIsed at building expansion joint and fan inletsoutlets Any others required should be indicated on the de ign drawings Care should be taken to maintain alignment across jointsconnections
183 Length Flexible Jomts shall be kept as short as pra middottieable above a minimum eft ctive length of SO mm In no ca e shall a flexible joint exceed 250 mm in lengtb
184 Connections to rectang a ducts With flanged rectangular connections Ule tlexible material shall be held in pLace with flat pIa tic strip of not less U1an 6 mm thick ltlttached to the flanges using uitabJe fixings The more heavy weight type of fleAible mateLial may also be obtained formed into a channel ection with corners fitted to give a neat air tight j int For pigot connections the Be ible material shall b held in place with flat pIa tic trips n t less than 6 mm thick
t 85 Connections to circular ducts With tlanged circular connections the flexibl material shall be held in place with flat plastic backing strips or proprietary clip bands with screw or toggle fast ners
186 Welded flexible connections (Rectangular and Circular) Where the parent and llexibl material are from imilar ba ed products they can be joined to the duct u ing the welding method described in Section 823
19 PROTECT VE FINISHES
191 nles otherwise stated all ductwork shall be mallllfactured in mat fial as pecified in tbis specification Any special coatingpaint fmishes to be provid d by the duct work contractor sball be advisd by th de igner
20 CONNECTIONS TO BUILDING OPENINGS
201 Fanning and finishing building op nings are not the repoJlsibjlity of the duftw( rk contractor and the note that follow are for guidance purpo e only
2011 Openings in brick block or concrete walls shall have inset frames to provide a suitable means of fixing grille louver masking flanges or the tlanged ends of ductwork The illset frames shall be conslnlcted to maintain the structural int grity of the wlll and where applicable cavities shall be suitably lined
2012 Openin s in dry linino partItIons shall have inset frames a 2011
2013 Openjngs in cladding walls and roofs shall have flaoged leevesframes to provide a suitable means of fixing a 2011
2014 Horizontal and vertical opening xposed to oLltside atmo phere hall
be provided with a suitable weathering fini h at the external face especially where profiled cladding is used
2015 Timber framed op nings are not permitted In fj re compart ment barriers
202 Ductwork connections to building openings hall have a flange of suitable profile to permit practical fixing to the openillg frame In selecting the profile consideration shall be given to Tabl~s 2 and 10 in this specitication relating to duct ize and rating Gasket strip or sealant shall be ltlpplied between the tJaoge and building op ning frame
21 DISCHARGEEXHAUST TERMINAL
21 Tbese shall be vertical open ended and designed to meet and comply with current r gularions on contaminated flue The designer hall ensure that the de ign and perf rmance i suitable for its intended purpose Examples of some typical terminal designs are SbOiD in Figbull 102 10 bull 104 amp 105
27
DW154 SpedjimioTl for Plastics Ductwork
22 THERMAL INSULATION
221 The provision and application of thermal insulation to ductwork is not the responsibility of the ductwork contractor
222 Where ductwork is required to be preshyinsulated the specification should be agreed with tbe designer
223 Where the temperature of the air within the duct promotes condensation on the exterior surface of the duct and cause moisture penetration througb the thermal insulation vapour scaling may be required and in this case the most important requirement is to limit penetration of the seal
The extent of any vapour sealing of ductwork thermal insulation and the support method to be u ed must be clearly pecitled in advance by the designer
224 For detailed information on the thermal insulation of ductwork reference should be made to BS 5422 1990 which covers the specification for thermal insulation materials on pipes ductwork and equipment (in the temperature range -40degC to +700degC) and BS 5970 1992 which is a Code of Practic for Thermal Insulation of Pipework and Equipment (in the temperature range -lOOdegC to +870degC)
23 FIRE RETARDANT FINISHES ON PLAST C DUCTWORK
231 The designer should note tbat ductwork constructed to DW154 has no teted fire rating or information see Appendix C
24 REINFORCEMENT OF DUCTS WITH GRP LAMINATE
241 General Where ductwork is required in larg T izes than are covered by Tables 2 4 6 amp 7 or with the increased strength sometimes necessary for industrial use external reinforcement is normally pwvided by applicatioD of glass fibreresin laminate
GRP systems will bond satisfactorily with standard UPVC sheet but for pp it is
nece sary to use a specially prepared sheet with a glass fabric backing incorporated dOling manufactllfe
The detailed techniques of fabrication using GRP are outside the scope of this speci lcation but the following notes are offered for guidance of ductwork fabricators
242 Materials
2421 Quality The laminate is made up of polyester resin complying with BS 3532 and glass fibre complying with BS 3496 or BS 3749 The nominal ratio of resin to glass fibre should be 7030 by weight
2422 Minimum properties The laminate shall comply with the followiog mini mum pbysical properties
Tensile strength - 70 MNm Tensile modulus - 7 Gl m Flexural strength - 140 M Im Bond strength (hetween laminate and substrate Not less than 7MNm Bmcol hardnes Not le s than manufacturers specification
The GRP reinforcement educe the expansion of the parent material but the resultant stre ses arc well within rhe strength of the bond However the Iinear thermal expansion curve shown in Figs 34 amp 35 will serve as a guide
Surface resistivity electrkal propcltles and acoustical propertie are similar to the relevanl unreinforced materials The fire retarding properties of GRP may be improved by the use of specialisl laminating resin
2423 Forms available GRP Laminate should be built up from the separate materials ie resin aod glass fibre in the form of chopped
I strand mat or spray ravings
28
DW154 Spcification for Plastics Ductwork
2424 Workshop conditions Polyester resuls are sensItIve to lmperature and the workshop hould b maintained at a temperature of herween 20deg and 25degC HiOh relative humidities and damp onditions should be avoided A good rate of air change must be pro icled pJeferably by m chanical ventilation
2425 Storage of materials Resin and urin o agents shouJd be stored in dark cool condirions away from the working area and in confonnit with statutor requireshyments for tJle middottorage of flarmnable liquid Because of Ule Limited torage lif of the unmixed resin and curing a eot mal lials ~hould be ch eked before use to enLlfe that they are within the manufacturer pe ified sh If life (usually ix month from the dm of manufacrure)
Glass fi re should be stored separately und r clean dry conditions
243 Surface preparafon
2431 UPVC To achieve the specified bond strengtll the urface to which the GRP is applied mut first be thoroughly cleaned and then etched either by mechanical means or by the use of a suitable solvent
2432 pp with glass fabric backing To achieve the specified bond middottrength the fabric backing must be thoroughly impregnated Witll resin
244 Mixing the materials for use The re in 1 a three part mix compri lng base I sin hardener and accelerator The manufactur rs pecj[ied proportions are critical and th llUxmg sequenc pecified must be meticulously foUowed
The resin has a very limited life after mixing and before u e It is dependent on the characteri tics and bulk of th resin the alllount of hardener the degree and method of acceleration and the workshop onditions
245 Methods of application
2451 General The mixed resin may be applied by hand or b pray c1epoition The operation must b completed within the gel time of th y tern and tbe laminat fully cOI1olidated to achi v the phy ieal properties pecified
2452 Hand lay-up The duct surface i coated by hand with resin Llsing a brush and a mar of gla fibp orked in until full consolidation achieved Th proc is repeated untiJ th requird thicknes i obtained
2453 Spray depo Won The duct surface is coated WiUl re in by spray gun with the chopped glass roving added through a separate nozzle The full thickne i obtain d in layer with con olidation of each layer by hand roller
246 Construction
2461 General M ini mum COllst ructional requireshyments are pe itied ill Tabl 10 for rectangular and Table 1J for circular dUClS
2462 Joints and stiffeners Fig 29 30 31 32 amp 33 hoI TOSS
joint and tiffener for reinforced UPVC and PBPP duct
247 Worki g practices The fabrication of ductwork pecifiecl ill thi document i not affected by the addition of GRP
29
DW154 SfJcdJicatiOt for Plastics Ductwork
Table 10 Minimum constructional requirements shy
Longer Side Minimum Sheet Thicknes and
GRP Reinforcement
UPVC FBIPP 1 2 3
mm mm mm Up to 1000 3 plus 3 plus
06 kgm2 06 kgOIl GRP GRP
1001 to 2250 45 plus 3 plus 06 kgm 12 kgm
GRP GRP
2251 to 3000 45 plus 6 plus 12 kgm 12 kgm
GRP GRP
Cross Joints
UPVCFBPP 4
mm socket amp spigot
as Fig 30 or flanged as Fig 29
75 x 9 flange welded on both sides as Fig 29
75 x 9 tlange welded on both sides as Fig 29
rectangular GRP reinforced ducts
SlifTeners Maximum Spacing Between
JointsSljffeners UPVCIFBIPP UPVCFBPP
5 6 mm mm
75 x 9 flat 800 as Fig 31 or
50 x 50 x 5 plastic or MS inverted angle as Fig 32
or tormer as Fig 33
75 x 9 flat 600 as Fig 31 or
50 x 50 x 5 plastic or MS inverted angle as Fig 32
or former as Fig 33
75 x 9 flat 600+shyas Fig 31 or 50 x 50 x 5 plastic
or MS inverted angle as Fig 32
or former as Fig 33
Note 1 On rectangular duct up to 400 mm longer side no stiffeners are required 2 Applies to Tables 10 amp I I For COlJstructional operating temperature limits refer to Part 2 clause 5A 3 Tables 10 amp II apply to all pres ure classes up lo ]500 Pa
Table 11
Diameter
1 III
lJp to 1000
1001 to 1750
1751 to 2500
Minimum Sheet Thickness and
GRP Reinforcement
UPVC FBPP 2 3
mm mm 3 plus 3 plus
06 kgm 06 kgm GRP GRP
45 plus 3 plus 06 kgm2 18 kgm
GRP GRP
6 plus 6 plus 12 kglm2 18 kgm1
GRP GRP
Cross Joints
UPVCFBPP 4 III
socket amp spigot as Fig 30 or flaoged as Fig 29
75 x 9 flange welded on both sides as Fig 29
75 x 9 flange welded 00
both sides as Fi 29
inforced ducts
Maximum Spacing Between
JointsStiffeners UPVCIFBPP
6 mm 2400
800
600
Stiffencrs
UPVCFBPP 5
mm 50 x 9 flat as Fig 31
75 x 9 flat as Fig 31 or former as Fig 33 75 x 9 tlat as Fig 31 or t()rmer as Fi 33
ote On extruded tube tip to 600mm diameter no stiffenergt are required
30
DW154 Specificatioll for Plastics Ductwork
G - Cross joints and tiffeners
Fig 29 Flange Joint Fig32 Stiffener shy inverted angle
M artiPfCuQkbdd erttpObri) Wl111 RP tlddtlt
_- GRPloliu] lh~
Fig 30 Socket and spigot joint Fig33 Stiffener shy use of former
Fig 31 Stiffener Flat
I Pv FlPP ~ ~lmJaDUA1) d
OMrlQ rrnall 1( tQlS
25 STANDARD COMPONENT DRAWINGS AND ABBREVIATIONS
251 The illustrations in this section not only highlight where applicable geometric limjtations for the de ign and manufacture or ductwork components but also recommend
standard drawing representation terminology and abbreviations for both duetwork components and some of the more commonly used ancillaryplant items
252 Designers and surveyors should note that bills of quantities should provide a full description
3)
---
v
DW154 Spcc(fim(ml for Plastics Ductwork
Fig 34 Linear Thermal Expansion
u c 0 N ro 0)
b 0)
S
sect0
5 oS cl) 0)
~
on ~ ltl
c U
-30 -20 -10 0 10 20 30 40 50 60 70 80 90 TEMPRATURE C
~ V
-
~~c_ ~
~V
V ~
-7 ~
-- ~V ----
v
-6
+14
+12
+10
+8
+6
+4
+2
0
-2
--4
ig 35 Typical Design Stress tor UPVC and P
7
6
r shy 5E
-c E----0 4t) VJ 0)
ci5 0Jl 3
~
0)
Cl
2
1
o
UPVC
1
000
1
1
pp
- r-- shy r----- shy - t--shy I
__0
-30 -20 -10 0 10 20 30 40 50 60 70 80 90 TEMPERATURE C C
Note Figso 14 amp 35 shaded area refers to GRP reinforced duct
32
DW154 Speciicfltirm for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - REC ~NGULAR
Splilt~r Posilion W-mm pliucr
A B c 40]--QOO 1 W - -
601-1000 1 W4 Wf2 -
1001-1800 3 WI W3 W2
FIG DRAWING DETAfiS
tU]36 ATI Straight Duct with socket and spigol joint
rn [037 Straight Duct with flanged joints
[I []38 Straight Duct with flanged joints
rkJ Short Radius Bend
39 Applies to any augl and for duct up to 400 n11n wide
Minimum (I1m31 radills = 100 mm
Medium Radius Bend (a illustrated)
[kJ Applies to any angle
40 Long Radiu Bend Similar but radius = W
Throlll radius = W2 Applies to any angle
- Short Radius Bend with plitlers
I -shy -shy u co - t lt Li--_ 41 t 0 ~ I I I
~ I
L 1W
Minimum waal radius = 100 mm Splitters not required in bend angle less than 45deg
42 QJ1 Square Bend with turning vanes ij
3
DW154 SP(L~ficatioll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - RECTANGULAR
FIG DRAWl G DETADS
43
~
I v
L L Radius Tee with internal deflectors
44
~ Radiussed Twin Bend
45
Imiddot
er Swept Branch
46 U-
Sqoare Tee with Turning Vanes
47
~ f
Breeches Piece
48 0 y l Piece
34
DW154 Specificatioll for Plastics Ductwork
STANDARD COMPONENT RAWINGS - ECTANGULAR
55
54
51
50
53
52
49
FIG
~MX
RAWlNG
DmiddotMAX
EfjMAX
Minimum throat rndius = 100 mm
Rectangular shy Round Transformatioll
Eccentric Taper 225deg max in either plane Spliller are required for angles greater than 225deg and hould bi eet the angle between any side and duct centreline
DETATLS
Angled Offset
OUset Taper Splitters are required for angle greater than 22 0
and shoold bi eet the angl between any side and dUCI centrelinc
Mitred Offset
Concentrk Taper 2250 max in ither plane SpUtters are required for angle greater than 225deg and should bisect the angle between any side and duel c ntreline
Radiussed Offset
35
DW154 Splcilcuthm for Plastics Ductwork
STANDARD COMPONENT DRAWINGS ~ RECTANGU AR
Branch ducl DimCllsions widlh (W) (A)
urnl mm up lO 200 75
300 100 400 125 600 150
Ocr 600 200
FIG DRAWlNG DETAILS
56 poundplusmni~~ Rectan~lar - Flat Oval Transformation
57 [ Square Branch
58 er Angled Branch
Branch dUCI Dimensions wfdth (W) (A)
[- mm mm59 3shy Shoe Branch Up (0 200 75
--shy AIshy + 300 100
400 125
450 MAX 600 150
Over 600 200
Branch duct DimensIOn
rP X width (W) A)
60 - 1--shy _
~ mm mm
Bell Mouth Branch pto 200 75 300 100 t 400 125
600 150 Over 600 200
0=0 61 -
~ Bell Mouth
- shy T 4-5deg M x
--I 1-shy
TJ
62 X I ] I
Tele-scopic Joint I Illustrated with flangeL
X63
SBD Single Bladed Damper
36
---
DW154 Spedicatioll for Plastics Ductwork
STANDARD OMPONENT DRAWINGS - RECTANGULAR
DRAWING DETAILSFIG
64 on-Return DamperNRD shyshy
shyXbull
Multi-Leaf Damper Can be piggoted or flanged oppo cd or parallel blade
Alternative controls areshy
q p [gtshy
J HD65 Hand
~MD otori ed
PO Pneumalic
L-lt
l 13G 66 Blast Gate DamperX X
FireSmoke DampersSleeves
211r Ratinggtshy----
L_-
---
----
r----
Ir-- shy
IL- _-l
2hr
With i tallation frame
67 41 r Rating
4hr
Smoke damper SD
Intumc cent Sleeve L-d
37
DW154 Specijicutiolt for Plastics Ductwork
FIG
68
69
70
71
STANDARD COMPONET DRAWINGS shy REC ANGULAR
DRAVING DETAILS
gtshy Access Openings
AP 6 Access Panel - Rerno able
w [ ~ Access Door - Hinged
I ~le Inspection Cover
le -I reg -lt
~X X Flexible Connection
~ Drop Cheeked Radiussed Twin Bend
U Drop Cheek Bend
I
72 Air Flow SymbolX
38
DW154 Specifim[ioll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - ECTANGULAR
FIG DRAWING DETAILS
73
74
75
76
77
Q
Q
rp---t
~
V- I Ir---I
JL --11
THE ABOVE DETAILS TYPICAL PLENUM
Air Terminal Plenums
Plenum with side connection
Plenum with top connection
Cover plate with connection
Special plenum with connection
elescopic conn ction in direction of air flow
39
DW154 SpecijicotiOll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG
78
79
80
81
DRAWING
-23~---pound3-(MALE) (FEMAJE)
-t=j--_j(--d-shy
--L
~ THROAT RADI S= D AS T NDARD
e ~
THROAT Rjf)lU = D A MU)
DETAILS
Straight Duct With male and female connectors
Straight Duct With flange joint and slip joint
Bend MouldedIFormed Applies to any angle ego 30deg45deg60deg90deg Medium radius bend as illustrated Long radius similar but throat radius 0
Segmented Bend 90deg four section minjmum as illustrated
Other Angles 60deg = 3 sections 45deg = 3 sections 30deg = 2 sections
I
i
40 shy
DW154 Speciicafinll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG DRAWING DETAlLS
82 Segmented Twin Bend Radius = D2 max
May also be fabricated from tube
83 Equal Tee MouldedIFormed
84 -~ 1in Bend MouldedIFormed
85 Taper Concentric 1 0 as iUu trated Eccentric 30deg iJJcLuded angle
86 Short Taper
41
DW154 SpcUicatol1 for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG DRAWING DETAILS
87 30 max Offset
Angle Branch
Bran h dUCI Dimcnsions dia (D) lA)
Shoe Branch mm mm 88 Cl
Off rectanguJur Up 10 200 75 lOO 10 400 125
- 00 150 Over 600 200
Bl1IllCh duct DimenlOns din (D) (A
~-$a-Conical Branch mm mm
89 Also acceptable with Up 10 200 r
full conical surface 300 10
400 125
END VrE -shy 600 150 Over 600 200
90
m 75
100 12 150 200
mm Up to 200
_ 300 400
600 Over 600
iUtred Branch
Shoe Branch
J-L----U ~ Bell oulh Branch
ENDV1EW
93
92
91
42
DW154 Specificatiol for Plastics Ductwork
STANDARD OMPONENT DRAWINGS - CIRCULAR
FIG
94
DRAW G
I
~ 30deg 090deg
Breeches Piece
DETAILS
95 amp-----~ Blank End
~-----p Multi-Leaf Damper Can be piggolcd or fianged opposed or parallel blade
Alternative controls areshyri=-+- L-T~
I
---
LT~
I r- -
-+1
J HO Hand96
bMD Molori cd
PD Pneumatic
tl-shy bull
Single Bladed Damper 97 ~ saD
on-Return Damper Vertical application only 98 m~D
43
DW154 Sf1tcificatioll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG
99
100
101
102
DRAWING
$ I-
2hr
1 4hr
SD
~v I I
CO TINENTAL COWL
DETAILS
Iris Damper
Fi reS moke Dam persSleeves
2hr Ratillg
With installation frame
4br Rating
Smoke damper
Intumescent Sleeve
Access Openings
Access panel - removable
Access door shy hinged
fnspection cover
Discharge Continental Cowl
44
DW154 Sp(Cii(ltJll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
DRAWINGltIC DETAns
-
I
I
~
I I I High Velocity Discharge Terminal 103 I
I
I I
J I I 1 ~--
Offset Stack Discbarge Terminal 104 1
~ I e --(-
I
N
I
I
I~
I I Vertical Oischarge with Weather Cowl 105 I
--1--1 I
I
GAPI I
RTl AL DISC) lARGE WITH W ATIIER COWL
45
DW154 SpecUicatoll for Plastics Ductwork
STANDARD COMPONE T DRAWINGS - PLA TEQUIPMENTIMISCELLANEOU
FIG DRAWING DETAILS
106 ~~~ Rectangular Attenuator
107 ~- Circular Attenuator
108
~ Beod Attenuator
109 J ~(f) Heating Coil
110 J ftte Cooling Coil
III Jc[ Electric Heating Coil
112 X F
Humidifier
113 [H XX Axial Fan
114 ~fB1famp Noo-standard Ductwork Cross hntchillg (of any separate type) indicates by reference to a key any non DVil54 ductwork system
115 2llIIIIJIIIIIll Flexible Ductwork
46
DW154 SJeCUicll(iol1 for Plastics Ductwork
TABLE 12 - STANDARD ABBREVIAT ONS
ABBREVIATION FLL
AD Acces Door
AFF Axial Flow Fan
AHU Air Handling nit
All Aluminium
AP Acess Panel
AT Attenuator
AV Air enninal Unit
BE 81ank nd
BQ Blast ate Damper
CC Cooling Coil
CF Centrifugal Fan
CTA Cross alk Attenuator
CVU Constant Volume Unit
DP Drain Point
EEC Electric Heating Coil
El Expansion Joint
FAl Fresh Air Inlet
FA From Above
FB From Belo
fBPP Fabric Backed Polypropyl-ne Sheet
Flexle Flexible Connection
lexfD Flexible Du t
C False Ceiling CO an oil Unit
fD Fire Damper
FFL Finished Floor Level
FJ Flanged Joint
FOAM Rigid Polyurethane Self xtinguishing Foam
FOB Flat on Bottom
FOT Flat on Top
GAM Galvanised after ManufacttrJc
GRP Glass Reinforced Plastic
GSS Galvanised Sheet Steel
HC Heating oil
HD and controlled Damper
HH Hand Hole
HL High Level
HVD High Velocity Discharge
IC Inspection Cover
ID lri Damper
IFS Intumescent Fircleevc
47
DW154 Specification for Plastics Ductwork
TABLE 12 - STANDAR ABBREVIATION CONTINUED
ABBREVIATION
IU
L
tv1D
MS
NRD NTS
OBO
OE
PHD
PD
PP
PP
PRD
PVC
RFC
RSC
R
SBO
SO
S1 TST
SSL
TA
TB
TO TJ
TP
TV
TV
OS
UPVC
S
V
VAV
50 RSA
FULL
Induction Unit
Low Level
Motor controlled Damper
Mjld Steel
on Return Damper
at to cale
Opposed Blade Damper
Open End
Parallel Blade Damper
Pneumatic controlled Damper
Polypropylene
Self xtinguishing Polypropylene
Pressure Relief Damper
Polyvinyl Chloride
Rolled Form Chamlel
Rolled Steel Channel
R fUnit
Singl Blade Damper
Smoke Damper
Slip Joint
Stainl t el
tructural Slab Level
To Ab vc
To Blow
Top Down (In Direction of Flow)
Telescopic Joint
Test Point
TU111iog Vane
Top Up (In Direction of Flo )
Voles Otherwise Stated
Unpl3sticisecl Polyvinyl Chloride
Underside
Ultra Violet Light
Variable Air Volume
Rolled Steel Angle (Vith Size)
48
DW154 SJeriiflllioll for Plastics Ductwork
A2 DUCT PRESSUREAPPE DXA Ductwork con truct d to DWIl54 will bebullbullbullbullbullbullbullbullbullbullbullbullbullbull
Air Leakage From Ductwork To be read in conjunction with DW143 A practical guide to Ductwork Leakage Testing
CAUTION As highlighted ill both this docul1lenr and DW14 I lot ellough emphasis can be placed 01 the fact that except for high pressure class C the much more stringent ductwork constructional standard brolght about b the general acceptance of DW154 have irtlally negated the requirement for leakage-testing It is essential lO realise lhat except where it is mandatory this doclllllelll is nOl an endors ~lIlent of the rourine testing of ducts bllt purely a guide to outline the procedures for cononnity with the air leakage limits ill Table l Where the specified methods of assembly and
A3sealing of dlcls are u ed a vi ual inspection wil ordinarily sl~fll e for ver(iatioll of a well engineered and a ceptahfy airtight COl1strucrioll WHERE NOT MANDATORY DUCT LEAKAGE TESTING IS GENERALLY AN UNJUSTIFIED AND SUBSTANTIAL EXPENSE
A1 INTRODUCTION L akage from ducted air distribution systems is an Lmportant consideration in the design and operation of ventilatjon and air conditioning middotystems A ductviork t)ystem tbat ba limited air leakag within defiucd limits wiH cnsUft
that tile design characteristics of the sytem can be maintained It wilJ also ensure that energy and operatLonal cosb are maintained at optimum levels DucLwork constlucted and Ulstalled in accordance with DW154 should minimise a level of air leakage that it) appropriate to tll operating static air pre sur in tile system
A4However it is recouuised that tbe environment in wtJich middotystems are installed is not always conducive to achieving a predictable level of quality in term of system ajr leakage and it is therefore accepted that designer may sometimes require tlle ystem to be tested in part or in total It should be ecogni ed that the testing of duct systems add a ignificant cost to the installation and incur some extra tjm within the programme (Se 47 and 64 re mandatory te-sting)
manufactured to a structural standard that is compatible with the system operating pressure There are three classes of duct con truction to eorre pond with the three pre ure clas meations Class A Lo pressure ducts suita le for a maximum positive operating pressure of 500 Pascal and a maximum negative pressure of -500 Pascals Class B IVledium pressure ductmiddot suitable for a rnaxilnuJJl positive operafjn o pressure of 1000 Pascals and a maxllnum negative pre sure of -750 Pa cal Class C High pre sure ducts suitable for a maximum po ilive operating pressur of 2000 Pa cals and a maximum negativ pres ur of -750 Paltcals
LEAKAGE FROM DUCTWORK Leakao-e front pia tic air ducts occur at the joint~ and is therefore proportional to the total surface area orthe du twork in th system Tb level of leakage i imilarly related to tIle air pres ure in th du t system and whilst there LS n precis formula for calculating the level of air los it i generally accepted that leakage will increase in proportjon to pressure to rbe pOvver of 065 The effect of air leakage from high pressure velocit ductwork is critical tn terms of system perfomlan dege energy consumption and the risk of high frequency noise as ociated with leakage These problems are le critical with medium pressure 10 ity systems but should be con idered Low pres mevelocity ducts present the lowe~t
ri k in tenn of tbe effect of leakage on the operation of the s stern
SYSTEM LEAKAGE LOSS As there i no di ct relatLonship between th volume of air conv yed and the surface area f the ductwork sy tern required to match the building configuratmn it is difficult to express air leakage a a percentage of total air volume Similarly the operating pressure will vary throughollt lh 3 system and a leakage is related to pre me the calculations ar comple However it is generally ac epted tbat in typical good quaJjty systems the leakage from
49
DW154 Specificatioll for Plastics Ductwork
each class of duct llnd r operating condition will be io the region of CIa S A low pressure 6 Clas B medium pres un 3 Clas C high pressure 2
A5 SPECIFYING AIR LEAKAGE TESTING Re peeting both the co -t and programme implications a sociated with te ling du 1 for leakage the designer may for example indicate that a particular system is te ted as follow
a) High pressure ducts - all tested b) Medium pr ssure duets - 10 of the
ductwork shall be s eet d at random and tested
c) Low pre sure - unte ed In any case where a random te t i elected for medium pre sure ductmiddot the followin c1au~e is suggested for inclusion by the de ign r
The designer hall elect at random a maxirnwlI of 10 of the dUCl system to bt tested for air leakage The duct hall be tested af the pressure recommended in Table J3 for the assifi atiol for the ectiol1 of the ductwork that is to be tested The tests shall be carried Ollt as the work proceeds and prior to the application of thermal insulation In the event of test failure of the randomlY selected section the designer shall have The right to select two La1her e tiolls at random for resting Where succes ive failures are identified there shall be a Tight to require rhl COl11raCWr 10 apply remedial attention to the complete ductwork system Th contractor shall provide documented eviden e of the calculalions used to arrive (1
the allowable 10 I for the section to be tested and the client or his agent shall willess and sign the results of the test
able 13 Air leakage rates
Maximum leakage of duct work Static
prcssUft Low-pressure edium-prc-sure I Iigh-prebull me diJfercntial Class A Class B Class C
1 2 J 4 Pa Litres per second per quare metre of surface area 100 054 018 ZOO 084 028 300 110 037 400 132 044 500 153 051 600 058 019 700 064 021 800 069 023 900 075 025
1000 080 027 1100 1200 1300 1400 1500
029 030 032 033 035
1600 1700 1800 1900 2000
036 038 039 040 042
Note Recommend d mean test presures are highlighted iD bold type with the actual selection being left to tll test operator
50
DW154 Sfeeiieaioll for Plastics Ductwork
A9
A10
and air leakage classification for the y em under test
DESIGNERS CALCULATIONS The designer can middotaJculate with reasonable accuracy the predicted total loss from a ystem by
a) Calculating the operatin presure in each ection of the sy tern
b) Calculating the surface area of the ductwork in each correspondin pre lire s ction
c) Calulating the allowabl~ los at the operating pressure for each ection of the system (see table 13 for allowable leakage figures)
VARIABLE PRESSUR S IN SYSTEMS De igner can achieve significant co t saving by matchina operating pressures throughout the system to constmctional standard and appropriate air leakage testing eO the practice of specifying construction tandards for whole duct sy tems based on fan discharge pre sure may incur unnece sary costs on a project For example ome large sy terns ould well be classiC ed for I akage limits as follows
Plant room risers CJas C Main floor distriblltJou CIa B Low pre sure outlets Cla A
A6 SPECIAL CASES There may be ~itLlations on a project where circumstance dictate thal pecial consideration be given to containing air loss s eg a long mn of duclwork may incur a di -proportjonate level of air 10 s In ca es such as thi example the designer can specify an improved tandard of airtighmess ie 80 of alJo~able 10 s for la B Ju ts The designer sbould not specif a CIa C t sI at CIa s C pressure for a CIa s B ducl
A7 SUGG S ED RANGE OF TES ING
A8 TESTING OF PLANT ITEMS Items of inline pJant (eg Fig 106 to 115) will not normaUy be included in an air I akage test The dllctwork contractor may indud such itelllS in tbe te t jf rh quipm ot has a certificate of COnfOlnlity for Ihe pres ure clas
bull High pressure duct bull Medium pre sure ducts bull Low pre sur ducts bull Exposed extract syst ID bull Ceiling void extract
systems bull Secondary ducts from
VAV or fan coil units bull Flexjble duct bull Final connections and
branches to grille and diffusers
100 test See A5 Untested UDt sted
Untested
Untested Untested
Untested
SI
i
DW154 SJecijicafion for Plastics Ductwork
ig 116 Permitted leakage at various pressures
Leakage in litres per second per square metre duct surface area
Vgt
o ltgt 0 ltgt N
ltgt Cgt
0 0 cc
0 0
~
g =
g ~
c 0
J
ltgt 0 I
~ ] tn
ltgt ltgt
In ol
~ 0 ~ 8 ~
~
c ltgt ltgt
~ CJ
~ ~ ~ ~ 8
0shyij
~ ~ ~ t
ltgt ltgt 00
l
~
~ Q
c C
~ rshy
e ltgt
I 1
I Cgt ltgtv
c Co ~
~~ ~ 10
I
0 Cgt
fJshyq 410 ) 1 ltgt
ltgt N
~ shy ltgt ltgt
~ I 1
c
52
DW154 Specificatio for Plastics Ductwork
Example of a completed test sheet Test No
General
Name of job N~ jC43Pt(r2lef Building Repound ~(~~0
Part 1 - Physical details
a Section of duct work to be tested ~(diffPIfff~el1f3rd Floor
b Drawing Number g91~~ c ssure aSSJ L atlOn V~Jl~IRfYgtg~~lPre Cl T Class C
d Test static pressure -(9 raErq~ ~~~~-~~J~~~ ~~ ~~~~ll
Leakaoe factor 9~-tre3$ecMz I OM REFTOTABLE 13)e b bullbullbullbullbullbullbull
f Surface area of duct under test Q~tJJItetre$ CPROMCALCU TIO BELOW)bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull ampampamp bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull
g ]Vlaxi mum permitted leakage -~ (~i~~0 ~~r~~ ~~~l-~-11~ ~~~Q
Part 2 - Test particulars
a Duct static pressure reading 9QFt~q~ ~ middot~~~1 ~~
b Manufacturer and type of liow measuring d vice (-~~~cJ~Y-9Q7EYg c Range of measurement of now measuring device QtP)OQ~(e~~~0I~~~~1~I~ ~~~~~~W~
d Reading of flm measurin o device pmiddot IFROM RIO)ftscag ~
I (DERlVED [ROM CHART SUPPUED WITH RIG US 0 ud)1e Interpreted air flow leakage rate ~(~~~f~~~ (~l~~~~~~~~~~~~~~~~~I
f Duration ~~~~~norn~allY l~ lnil1Ut~~d~~~ it1~ W~ Date of test ~(lITled ut by Wltll s ed by ~ ~
(~lJ MIJLrr) (Si~rrfltJUYJ
Printed Name 1~g0f~ Printed Name ~~Y~9~ and Company 7jl~~~~~( UJd CompanY AB COII$Itallt8
Width and depth or diameter
Periphery ength Area
millimetreS millimetres metre qL1are metre
800 x 750 3100 1755 5440
600 x 650 2500 557 1193
300 x 300 1200 120 144
305 din 958 700 670
250 dia 785 450 353
TOTAL 8000
53
DW154 Specijilarion for Plastics Ductwork
pA XB
Guida ce No es For he ransport Handling and
Storage of uctwork
avoid damage to adjacent duct panels In somc ca es particularly on con acts calling f r repetitive sizes the use of timber jigs and spacers may be justified Where reduced bulk and greater protection are major factor such as consignments for export transporting ductwork in L shape sections may justify the increa ed ite as embly co ts
It is recommended that before a contract is finalised that consideration is given to the subject of site acces material handling and storage as tbcy havgt a strong influence on the cost efficiency of the overall activity of ductwOlk installation
B3 Handling To minilnise th risk of damage duct sections should be clearly identified and deliveries to site should be closely linked to the installation programme so as to avoid accumulation of
B1 Storage and Handling of Ra Material Material should be stored in suitably designed racking out of direct unJight Where possible the e racks should be metal to earth Edges of cut she t may be harp and protective gloves are advised Wearing teel toe-capped boots is recommended Most pIa tic sheet is manufactured with smootb mfaces andor is suppLied with protective coating Care must be taken to prevent accidental lippag of stacked materials Beiuoshy good electrical insulators the movement of stock unless earthed will allow the build up of stati All stock shapes are chemically stable at normal temperature Whil t some raw materials used in their manufacture may themselves pre ent a toxic hazard once incorporated into the lOck bape they no long r constitute such a hazard and no dermatitic bazard are known nor are any
unfiJied ductwork and minimise double handling It is important to recognise that ductwork panels joint and corners arc susceptible to damage and care must be taken wheu band ling such material through a site During handling individual item of duct work may be liable to light cross sectional deformation until thev become an integral pan of a completed ductwork system Whilst this may temporarily detract from its intended appearance thi deformation will not have any detrimental effect on the functionality of the finally a semblecl system Installation of duct work and asociated plant items ill illevitably involve manual handUng The responsibi Iiry of employers and employees to a ses the risk of personal injury during mallual handling operations is et out in the HS E publication L23 Guidance on Manual Handling Regulations 1992
environmental problems expected 84 Site storage
B2 fransport Large capacity vehicles with high-sided open or closed-top bodies are tlle mo t suitable for the transport of dllctwork Careful consideration should be given to the
Adequate floor space IDust be provided within tbe building for the site storage of ductvork Such storage shalt make due allowance for thc stOf(ne of ductwork in stacks such that access ~ egt
between them is of sufficient width to pennil the removal of item without interference to
unloading of transport on sit a not all siJes b n fit from the material handlino- and access facilities that exi [ in a manufacturing workshop such as crane- fork-lifts or loading bay Site handJiog facilities along with
adjoining sta ks Ductvork components should be positioned so a to avoid crushing Ductwork of small panel size may be stored horizontally however care should be exercised to ensure that tack sizes are limited 10 within
ehicular acce s restrictions may itilluence the type and ize of transport to be uWised
engtlls of ductwork should be positioned 0
the tmctural strength of the duct sections to prevent distortion of the lower sections within the stack
as to avoid crushing Lengths Witll projections such as branches and bends i1anges girths damper quadrauL should be loaded so as to
54
DW154 S1tciic(ltioll for Plastics Ductwork
85 Internal cleanliness of new ductwork The site storage of ductwork introduces the important cODsideration of maintaining the internal cleanliness of the ductwork R feren e should be made to HVCA documentshybull DWffM2 Guide to Good Practice - internal
Cleanliness of New Ductwork Installations If the above conditioDs can not be satisfied consideration should be given by tJle designer to amending the specification to include for Po t Installation Cleaning as covered by tJ1C HVCA documentshybull TRJ17 Guide to Good Practic - Cleanliness
of Ventilation Systems
APPE DIXC
Fi e Retardant inishes C1 Improvement in the fire retardancy of plastic
ducts can be achieved to varying degrees and is wholly dependent llPOll the surface coating laminating resin selected and construction specification adopted In some instances smoke emission is coILSidered equaUy with other speci fication requirernen ts of the materials resistance to ignition and bumjng It is therefore important for design rs to establ ish the clients and officers detailed requirements and not rely on a tbird party interpretation of fire resisting or fire retardant Where possible the specification should refer dir etly to compliance with a British or European Standard identifying the specific sections applicable There are various types of resin and mat rcLnforcements that can achieve a Class 1 surface spread of flame ratin o when tested according to BS476 Part 7 (1987) This test puts materials illto Class I - 4 in descending order of perfoDllance according to the rat and extent of flame spread over their surfac under standard beating conditions Materials should also be tested for flre propagarion to BS476 Part 6 (1989) Tbi tesr measures the amount and rate of heat evolved by the material when subjected to standard heating
conditions Test results are given as an index of Perfonnance (i) whicb is based on three sub indices (iJ (i1) (h) The higher the value of the Index of Performance (i) the greater is the material s contribution to fire growth The higher the value of the sub-index 0) rhe greater the ease of ignition aod flame spread The highest product performance classification as defined in Approved Document B of the Building Regulations is Class O This is acLlieved if a material surface of a composite ploduct i~ either a) composed throughout of materials of
limited combustibility or b) a Class I material which has a tlre
propagation index (i) of not more than 12 and sub-index (i l ) of nor more than 6
01 J Class 0 is not a cla$sif1cation identified in any British Standard test
There are resin system reported to be classified to Class O when tested to BS476 Pcl1S 6 and 7 however designers need to ensure that such sysrems can be applied to their proposed design In propriety resinmat system available the fabrication techniques and COITect application are critical to the integrity of the reinforcing and clas ificatiol1 For example in some systems the u e of a non-fire retardant gelcont on a fire retardant substrate would reduce the classification For further information see HVCA publication DW144 Appendix D
55
DW154 SplCijiClIliol1 for Plastics Ductwork
x Guidance otes For nspectmiddoton Servicing a d
Clean-ng Access Openings
D1 GE ERAL This appendix highlight in ummary fOI111
the acce considerations that hould be made by the design r iD terms of inspection servicing and cleaning Having considered the seop and the design of the dUCI work system relative to the guidelines outlined below the designer should clearly indicate which levels of acces should be incorporated into the manufacture of a new duct work system (See Table 14 and Note I b low it
D2 DESIGN CONSIDERATIONS
D21 In ptction and servicing requireshyments are set out in Section 15 of Lhis specification
D22 Cleaning requirements are set out in the HVCA pubUcation TRl7 Guide to Good Practice Clean Lines of Ventilation Systems and the guide tates The precise location ize and
type of access would be dependent on the type of ductwork cleaning inspection and te ting metbods to b adopted Care protection and standards of cleanliness prior LO cOlllmisionin o
are set out in th AV A publication DWITM2 Guide to Good Practice Internal Cleanliness of New Ductwork Installations and th guide state Wh re specific limits of cleanliness are required ductwork sball be cleaned after installation by a spcialist cleaning contractor It will b in the interests of tht desioner botb financially and practically to cunsider employing a specialist c1eauing contractor at tbe
outset of a contract to internally clean newly installed ductwork prior to bandover This approach would reali e the following benefit shyi) Tb actual numb r of cleaning
access panels could be detennined to suit the method of cleaning to be adopted (This may be 1 s than the maximum requiremen listed under Lev 13 of Table 14)
ii) Clear directions could b given to the ductwork contractor as to tJle size and location of cleaning access panels that are required to be fitted during the mauushyfaclunng pro s
iii) The specialist cleaning operation prior to commi ioning vould enable the cleaning contractor to verify the practical acee requirement for the future cleaning operation associated -vitb a regular maintenance programme
iv) A specialist cleaning operation prior to commissioning would allow the designer to omit from the speeilicatiolJ the DWrrM2 requirem nt for factory sealing protection wipe downs and capping-off
v) Specialist Ieall ill 0 to the measurable standard defin d in TR17 will allow an objective definition of cleanline to be achieved
Car ful consideration must be gIven by the designer to the practl aJ problems associated witb the manufacture and fitting of suitably si Led access panel on small cross section duct and on the circular faces of rouod and flat oval ducts in particular
D23 Special con ideration must be given by the de igner to the practical problems associated with gaining personnel access to heavily congested ceiling areas and multi-la red du twork systems This approach would avoid
56
DW154 Spfciication for Plastics Ductwork
the possibility of access panels being D3 ACCESS 0 IN-LINE EQUIPMENT incorporated into a ductwork system at the This appendix unly covers acc il1spection manufacturing stage that were later found in through the ductwork body adjacent to an item practice to be inaccessible for either ervicing of in-line equipment and not openings in the or cleaning activities equipment itself
able 14 Acce requirements for inspection servicing and cleaning
HVCA PUBLICATIO REFE NeE (uidtgt 10 Gund Prartict
Adjace t OW144 Cleanliness orVcnlillltio S~lcr~ fRjJ7
in-line LeyeJ 1 Level 2 Level 3 ite sequipment pcdionSen lcin~ Section d C1eaniJl( SUn(O)lnspc lion Palle ltk~m_n
2011 (minimum OiL Jubje-ct to duct ~zel (ft~ -Panels
Control Da pcrs One (inspection) 203 One 300 mm x 200 mm Both sid Fire Dampers One (sCTjdJl~) 20211 One 300 0101 x 200 mm One side HeatingCooling Coils One (inspedion) 20213 One 300 mm x 200 mm (lIpstream) Both sides Attenuators (rectangular) None required One 300 mm x 200 mm (downstream) Both sides Attenuators (circular) one retluired One 300 mm x 200 mm (downstream) One side Filter Sections One (inspection) 20212 one required Uoth sides Air Turn Vanes None requjred None required Both sides Changes of Direction None required one required One side In-Duct FansDevices One (inspection) 20213 None required Both sides l
1 In the absence of any indication by the designer only Level ) access will be jncorporated into a new ductwork system
2 Tbe panel izes associated with Lev lis I and 3 acee s ar e middottablished by reference to Section 20 of DW144 and Section 2 ofTRll7 respectively
57
DW154 Speclfifatio for Plastics Ductwork
pA XE
B-bliography Included in this Bibliography are technical pUblications which may be of interest (0 ductwork designers fabricators and erectors and to tho e in the heating ventilatlng air conditioning industries generally nquiric should be made of the relevant organisation at the address quoted Since its publication other addresse contained within 0V154 mav have changed and some pubJicalions may have been superseded
HEATING AND VENTILATING CONTRACTORS ASSOCIATION
4 Palace Court London W2 4JG Telephone 020-7229 2488 Fax 020-7727 9268
Orders fo FlY A Publications Old Matlsion House Eamont Bridge Penrith Cumbria CA 10 2BX (Telephone 01768 864771 Fax 01768 86718) Email hvcapoblicationshvwelfarecouk DWn 44 pe ilicatiun for sheet mctal duclwork (Iow- mediulllshy
and high-pressure) 1998) DWIl4 A practical guide to dUGI ork I akage te ting
(revised 2000) DWII54 Specification for plastic~ duct rk DW171 Guide to good Practice for kitchen venlibtion system DW191 Guide to good pracuce glass fibre ductwoJk DwrrMI Acceptance cheme for new products - Redangolar cro
joint classification Guide to good pra tice - Internal cleanliness of new ductwork installations Guide to good practice for the design for the Installation of lire and smoke uampers
J 1Other puhlications
HampV safely guide 5th edition JS2 Tool box talks JS5 Weldlng Safety booklet JSI9 afety facts bo klet Fact sheets 1-24 2nd edition JS2J COSHH manual volume 1 Advice on compliance with the
regulations 1521A CO I-rH manual volume 2 Asses mcnt h ets JS23 Ri k management manual TR3 BrazinltT and bronze welding of copper pipework cUld sheet
(I 976) TR5 Welding of carbon steel pipework (1980)
TR6 Guide to Good Practice for Site Pre sure Testing of Pipework (19 0) Guide to good practice cleanliness of ventilation Ylem
CHARTERED IN TITUTlO OF BUILDING SERVICES E G EERS Delta House 222 Balham High Road London SW12 9BS rTelephone 020-8675 5211 Fax 020-8675 5449) CIBSE Guide Volume A Design Data Volume B In tallatiol1 and quipment Data Volume C Reference Data
CommlssioniJIg Codes These Codes eover the preliminary checkS eUing to work and regulation of vanous catcgories 0 plan The Codes give a guide to design implications Series A Air Distnbution Systems Series B Boiler Plant
ri s C Automatic Conlrol ystems Cr1es R Refrigerating Sy terns
Sene iN Water Distribution Systems
Technkal Memonllda TM 4 Design Notes for the Middle East TM bull Design otes for Ductwork TM 13 Minimi iog lhc Risk of egiounaires Disease
Research Reports RROI95 Ventilation system hygiene - A review of published
infomlatioo on lhe occurrence and ffects of Olltamination Rl~02J95 Air-to-air heal rec v ry RR0395 rnfluen e of HV C on smoke detectors
ATlONAL ENI [ERING SPECIFICATION LfMITED Southgatc hamber 3739 Southgate Street Winchester S023 9EH (Telephone 01962 842058 Fax 01962 R(8982) BUfLDING S RVICES RESEARCH AND [ ORMATION ASSOCIATIO Old Bracknell Lane West Bracknell Berkshire RG 12 4AH (Telephone Brackl1eU (01344) 426511 Fax 01344 487 -7 )
Application Guides AGln4 De tglJing Vana~le Volume middotylans for KOOnl
iir Movement AG1I91 Commissioning of V Sylcms in Buildings 11 6194 Fire Dampers
B) 94 cntiJalion or KitcneTls
AG389 The Commls ionin of Air Systems In Buildmgs AH2192 Commissioning of Bern - A ~ode of Practice TN2417 I Fire Dampec il) Ventilating Ducl
BEATING VENTILATING A AIR CONDITION G MA UFACTURERS ASSOCIATIO (HEVAC) HEVAC Henley Road Medmenham Marlow Buck SU 2ER (Telephone 01491 578674 ox 01491 575024 Emoimiddot infofetacouk)
Publicatjons Air Diffusion Guide Guide to Air Handling Unit Leakage Testing Guide to Good Practice Air Handling Unit Real Room Acoustic ~ st Procedure Specification for the ertiiicatioll ofAir Filters Method of Test for Water Rejection PerfOnTlatce of Louvrcs Subjected 1(1
Simulated Rainfall Test Procedure for Acoustic Loo cs Specification 10 Floor GrilJes - Types Performan e and Method ofTest Specification for the Determination of the Collection Efficiency of SilJ1d
Trap Louvre Domestic Mechwlical Vclltllalion Systems with Heal Recovery Fan Application Guid
~an and Ouctwork Installation Guide Guide to Fan Noise and Vibration
pecification of Requirements for JallJral Smoke and Heal Exhausl Ventilators
pecification for Powered Smoke and Heat Exhaust Ventilators
Specification of Requirements for Smoke Curtains Design Gujue of Smoke Ventilation for Single Storey Lodustrilll Building~
Including those with Mezzanine Floor and IIi Racked Storage Warehou es - Issue 3
Guidance for the Design of Smoke entilation YSlem for Covered and Undergrollnd Car Parks - lssue 1
Application of SOloke Control Equipment and Syst m Guid to Good Practice - Isue J
58
DW154 Sp(C~tiifitiol for Plastics Ductwork
BRITISH STANDARDS INSTIT TION Sales Department 101 P ntooviLle Road London NI 9ND (felephone 020-78 1 78801)
CP 413 1973 Ducts for building ervices
SS 476 Fire tes on building matenals and lruc(ure
Part 4 19 4 Non-combustibility lest or materials
Part 6 I Fire propagation lest for materials
Part 7 1993 Surface spread of tlarnJ tesls for materia
Part 20 1987 Fir resistance of elements of construction
Part 21 1987 Fire r sistlUlce of loadbeanng elements of construction
Part 22 1987 Fhe istallceofllon-loadbearing elemcllts ofconsttuclion Part 23 1987 Contribution of componcnts to the fire resistance 0 a
structure
Part 24t987 Fire resi lance of wl1lilation ductl
SS 5588 nan 919 0 Fire Precautions III thc desIgn and OOSlnJ lion of buildings
S 729 1971 Hot dip galvanized oatiugs (or irOIl aod stcel articles
BS 1449 Steel plate sheet and Irip
Pan 11991 Carbon steel plate heel and strip Part 2 1983 Stainless steel plate sheer and strip
and
B middotENJOI49-2 996 BSEN 10149- 1991)
BSEN 10131 1992
BSEN22063 Sprayed metal coarings 1994 Protection of iron and steel by aluminium and zinc against
atmospheric cOlosion Irotectiotl of iron and ste I against corro ion and oxishydation at elevared temperatures
BS 353 1981 Glossary of lerms relnting to thermal insulation
BS ISO 1479 Self-tapplngscrewsandmetallicdri c crew
B -lSO 7049
1994
B 4800 1989 Painl colour for building purposes B 4848 l0 rolled structural steel sections
Part4 1972 Equal and unequal angles BS 5422 1990 Specification for the use of therm illuating matcriulS
SS 5720 1979 ode of practice for mechanical veutilating and air C 11shy
dirionin bull in building
l3S PR 12814-1 Bend resting for plasric welds
SS PR 12814-2 Tensile testing for plastic welds
SS PR 13067 Appro altesting for plastic welds
BS PR EN I 100-] Vi ual in pection ofplaslic welds
SHEET METAL AND AIR CONDITIONING CONTR-CTORS NATIONAL ASSOCIATION INC (SMACNA) Headquarters 420 I Lafayeue Center Drive Chanlilly Virginia 2051-1209
Mailing Address pa Box 221230 Cbantilly Virginilt120 153-1230
Telephone (703) 803-2980 Fax (703) 803-3732
Accepted IJJdustry Pl3Gtice for Industrial Duct Constnlelion 197 ) i-rchitecmral Sheet kwl Manual ([993)
Comractors Guide lor Modification 10 ooslruerion Colllraets 1993 Ducted Eleclric Heat Guide for ir Handling Ssrerns (1994)
En~rgy ollservatioD Guidelines (1984) Energy Recovery Equipment yslClllS (199l
Fibrou GIns Duct onS1ntClion Standards (1992)
Fire Smoke amp Radiation Damper In tall Guide for HVA Syst ms (1992) Guide t leel Stack 1(95)
HVA Air Duct Leakage Test Manual (19 ) HVA COlllmissioning lvlanual (1994)
H A Duct Construction Standards-Metal amp Flexible (1995) Addendum 01 (Nov 1997)
HVA Duct Systems Inspection Guide (1989)
HVA ySlems-Application (1986) nVAC ByternS-DLlct D ign (1990)
HVi Systems-Testing Adjusting amp Balancing (1993)
indoor Air Quality Manual (1993) tcheu quipment Fabrication Guidelmes (1990)
Managers Guide for elding (1993)
Rectangular Industrial Duct Cons1TUction Standards (19 0) Round Industrial Duct oustmction Standards (1977)
Sei mic Restraint Manual (1991) (wl Appendix E 1993) SMACNA Ma le Index ()fTechnical Publications (1995) Tbennoplnstic Duct CPY ) Construction Manual 1994)
DEPARTME OF THE ENVIRO MENT (Publications Centre) H Stationery Oflice 5 Nine Elms Lane London SWS 5DR
MampEJ 011972 Electrical in tallat1011 in buildings ( ew Editiou)
IampE 0319 Healing hot and cold wat r steam and gas losla1lations for buildings
M amp - No4 1970 Central heating and hot and cold ~ ateT in tallations for
dwelling
M amp ENo100 1971 Mechanical ventilation for building~
ASSOCIATION FOR SPECIALIST FIRE PROTECTlO As ociation House 235 Ash Road AJdershot Hampshire GUl2 4DD
Telephone OJ25221322 Fax 0 J252 333901
lublicalioos Fire Ratcd and moke Outlet Ducrwork An Industry Guide t Design and InSlalla lioll
HEALTH AND SAFETY EXEC TIVE Rose Court 2 Southwark Bridge London SEl 9HS Telephone 020-7717 6000
TWJ THE WELD G TlTUTE Abington Hall Abington Cambridge CB16AL Telepbone 0 J223 89162
Publication DatJ Oil w~ldll1g of lhermopla lics
59
DW154 wciiwlioll for Plastics Ductwork
A -=--DIX
Factors
Specific gravity shy pp = 091 approx UPVC = 14 approx
Some miscellaneous conversion factors
To convert
Length Inches to millimetres Feet to metres
Multiply by
2540 03048
To convert
Millimetres to inches Metres to feet
vIultiply by
003937 3281
Area Square inches to square millimetres 6452 Square millimetres to square inches 000155 Square feet to square metres 00929 Square metres to square feet 10764
Volume Cubic feet to cubic metres Cubic feet to litres Gallons (UK) to litres
002832 2831 4546
Cubic metres to cubic feet Litres to cubic feet Litres to gallons (UK)
35315 00353
022
Mass Ounces to grams Pounds to kiJograms Tons to tonnes
2835 04536
1016
Grams to ounces Kilograms to pounds Tonnes to tons
003527 2205
09842
Volume flow Cubic feet per minute to cubic Cubic metres per second to cubic
metres per second 0000472 feet per minute 2119 Cubic feet per mIDute to litres Litres per second to cubic feet
per second 04719 per minute 2119
Motion Feet per minute to metres per second 000508 Metres per second to feet per minute 197
Pressure Inches water gauge to millibars 2491 Inches wateJ- gauge to pascals (Pa) 2491 I Pa = I ewton per square metre = 10-2 millibars
60
Heating and Ventilating Contractors Association Esca House 34 Palace Court London W2 4JG
Tel 020 7313 4900
e-mail contact Itvcaorguk web site wwwhvcaorguk
Fax 020 7727 9268
DW154 Spec([icatirJ1l for Plastics Ductwork
restucllOn splitters shall be provided Taper Transformation pieces from circular 10 square pieces reducers and transformation piec s or rectangular shall be made as long a shall be manufactured from the tbickl1 s of p sible and uJe angl ball be uot mor than material specified for the larger size ducl 225 (Fig 55)
loon Pa 1500 Pa
2 3 4 5 6 mm mm mm mm
3 socket amp spigot - - -or tlanged
as Figs 1 2 3 401 to 600 45 flanged 50 x 9 flat 1200 800
50 x 9 flat welded both sides a Fig 3 as Fig 5
601 to 1000 45 flnged 50 x 9 flat 800 600 50 x 9 flat welded both sides as Fig 3 as Fig 5
1001 to 1500 6 anged 75 x 9 flat 600 600 75 x 9 flat welded botb sides as Fig 3 as FieJ 5
or or 70 x 70 x 9 angle 50 x 50 x 5 angle
as Fig 4 welded both sides as Fig 6
N t For constructional operating temp rature limits refer to Part 2 Clause 54
Longer Pitch Bolt Size
Side max 2
mm 1m mm Up to 400 100 8 with washers 401-600 tOO 10 with washers
601middot1000 100 10 with wash rs 1001-1500 100 10 with oycrsized
washer
13
Table 2 inimum con tructional requi ments - rectangUlar nmiddotreinforce UPVC and pp
Joints Sliffeners Maximum spacinOLonger Side MillirnUlll She t between
Thickness Joint~S(iffi ners
mm Up to 400
DW154 SpedflCiltion for Plastics Ductwork
Cross joint - recta gular ducts
Fig 1 Socket and spigot joint (UPVC and PP)
Conlinuou weld joint on sile onlinuou- wcld
CT~r~T2
Fig 3 Flange joint (UPVC and PP)
ontinuou weld
Fig 2 Socket and spigot joint (UPVC only)
Fig 4 Flange joint (UPVC and PP)
S iffeners - rectangular ducts
Fig 5 Flat Fig6 Angle
Oatim wo]
Fig8 Bends - examples of hardTie rod assembly and easy
Hard
Fig7 With spacers Easy
4
DW154 Speci(uariml for Plastics Ductwork
Fig 9 Turning Vanes
HOWl G TYl AL EXAMPLE OF FOCI G
15
Ma vane length shy 615 mm
Example ofbraemg when V1IIle length exeeed max pennined Ahematively two banks of ncs fixmg the centre rail together at ] 50 mm nrrcs
U~_II---- fixed to dnct wall both CDds
bLEVATION
vane
Maximum distance between centrc oflUming vanes should [Jot exceed 60 mm pitch
DW154 SPCCijicllfiull for Plastics Ductwork
practice to provide common terms ofPA T4 reference for designers quantiry urveyor and
Circular Ducts
12 CIRCULAR DUCT SIZES Th duct sizes [n Table 4 have been selected from the ISO and C standard ranges as the 132 preferreod sizes
Table 4 Circular ducts shystandard extruded tube sizes
133 Extruded tube
ISO Standard Sizes (Nominal Diameter) 11
Wan Wall Thickness Thickness
mm mm mm mm 110 500 4022
I25160 600 50 I25200 630 60
225 25 700 60 13425250 800 63
280 900 70 315
23 23 80
355 1000
25 1250 104 400 32 1400 108 450 35
Note The above sizes are subject to normal manufactl1ring tolerances Other size may be available in varying wall Lhicknesses and subject to test and operational pressure
13 CONSTRue ION
13 General Tllis specification covers duct sizes up to a maximum diameter of 1500 mm The minimum constructional requirements for UPVC amp PPPPS un-reinforced ducts sball be as Tables 6 amp 7
ductwork contractors and tho e using computers in ductwork design and fabrication The requirements for circular duct fittings apply throughout the size ranges covered in this specification
Sheet jointing seams Seams shall be joined either by continuous fLiJer rod hot air welding or by fu ion welding Other forms of jointing are not acceptable
Socket and Sl)igot joints Socket and spigot joints shall be formed by purpose made double socket pieces 100 mm long and of the same thickness material as tJJe duct welded into position on each tandard length of duct forming 50 mm deep sockets prepared and ready for final jointing on ite with PVC adhesive andor fill r rod of the same formulation used for fabrication
Flanged joints
1341 Flanges abricated flanges shall be conshy
structed using minimum of 9 mm thick by 50 mm wide material of matching formulation depending on duct size as shown in Tables 6 amp 7 The flange shall be mounted true and square to the duct surfaces and welded OD both sides a 103 and Fig 12
1342 Drilliogs Drilling ball be placed to permit clearance to the external casing and any reinforcement of the ductwork
1343 Fastenings For normal application bright zinc plated bolts nuts and washers hall
16
For srualler diameters preformed fittings are available otberwise fitting are fabricated from segments of duct or sheet welded together
The terminology and description of circular duct tiltings as set Ollt in Section 25 are recommended for adoption as standard
be used in sizes and pitCh centres shown in Table S Wh re special conditions prevail consideration of other material finishes such as stain le steel bolt nuts and wasbers shall be u ed In all ca cs gasket materials as Seciion 825 shall be USed
DW154 Speciliwriml for Plastics Ductwork
135 Stiffeners
1351 External stiffeners Shall be fitted as specified in Tables 67amp 1 I and Fig 13
1352 Internal stiffeners The use of internal stiffening or bracing hall be acceptable if deemed neces ary and appn ved by the designer
f 36 Expansion joints Where the corrfiguration of the ductwork does not provide for movement due to temperature
Cross joints - circular ducts
change or where such movement is restricted by branches or attachments expansion joints should be fitted (See Section 18 Flexible Expansion joint connections)
It is the responsibiLity of the designer to identify the position of any necessary expansion joints based upon design parameters for the individual systems (See Figs 23 24 2534 amp 35)
Design Note Examples of expansion joints shown are not suitable for movement exceeding 30 mm
Fig 10 Socket and spigot joint (UPVC and PP)
ConLinuous weld joim on ite Ontinuous weld
crlr~l
Fig 12 Flange joint (UPVC and PP)
Continllous wcld
boil
Continuous weld or Solvelll cement
Solvelll ccmcnl joim on sile
Fig 11 Socket and spigot joint (UPVC only)
Stiffeners - circular ducts Table 5 Fastening centres shycircular duct flange jointsFig13 Flat
flat conljnlJou~ly welded Diameter Pitch Bolt Size
max
1 2 J 11
1 shy -~
mm mm mm Up to 600 100 8 with washers
601middot1000 100 10 with washers - ---I
1001middot1500 100 10 with oversized washers
1
Minimum offourfixings
17
DW154 Specifiiutiofl for Plastics Ductwork
Table 6 constructional quiremen s - circular unshy inforced U VC
Diameter Minimum Joints Stiffeners Maximum spa ~in r
Sheet between Thickness Jointsl tiffcners
1000 Pa 1500 Pa
1 2 3 4 5 6 UD mm mm mm mm
UO to 600 3 socket amp spigot as Figs 10 11
or fla ged Fig 12
601 to 1000 45 socket amp spigot 50 x 9 flat 2400 2400 as Figs 10 11 welded bo sides
or Oanged as Fig 13 as Fig 12
1001 to 1500 6 Hanged 75 x 9 flat 1200 1200 as Fig 2 welded both ides
as Fig 13
Applies 10 Tables 6 alld 7
Note 1 For constructional operating temperature limit refer to Part 2 luu 54 2 To allow for conicleration or extruded se lions or fabricated component the materia] tllicknes i hawn a nominal
Table 7 Minimu onstrucfional requirements shy circular un-reinforced PPS and
Diameter Minimum Joints Stiffcners Maximum pacio Sheet between
Thickness Join sStiffener 1000 Pa 150n Pa
I 2 3 4 6 mm m m mm
110 to 500 3 socket amp spigot as Fig 10 or flaoged as Fig 12
501 to 750 45 ocket amp spi~ot
as Fi 10 or Uanged as Fig 12
751 to 1000 6 tlanged 50 x 9 Oat UOO 12 0 as Fig 12 welded nth sides
as Fig 13 1 1 to 1250 6 flanged 75 x 9 flat 800shy 800
as Fig 12 welded both sides as Fig 13
1251to~ flangcd 75 x 9 Oat 600 600 as Fig 12 welded both sides
as Fig 13
18
DW154 Sped(icalirm for Plastics Ductwork
PARTS
Hangers an Suppo ts
14 GENERA
141 Supports are an e sentiaJ part of me ductwork system and their supply and in tallation are normally the responsibility of the ductwork contractor The principl s are a I-rvCA publication DWIl44 Part 6 Section 19 and should be read in conjunction with this document
Design Note Designers may pecify specific requirements wbich will supersede guidance given in DW144
142 Rectangular ducts abl 8 give the- minimum requirements for
hanger and supports for un-reinforced ductwork
143 Circular ducts Table 9 gives the minimum requirements for hangers and upports for uD-reinforced ductwork
144 Vertical d cts The design of supports for vertical duct is dictated by site condition and where practical duc hould be upported at 4000 mm interval or where tbey pa s through a floor (but n ver exceeding 4500 mm) see Figs 17 amp J8
145 External ducts Where ducts are external to buildings and may be ubject to wind loading support should be plac d so as to restrain ide tl1ruSt and should allow axial movement as neces ary It is the respon ibility of me de igner to calculate the effect of the particular prevailing condition and to define any special upport requirement
146 Expansion joints Support shall be designed to permit axial movement only and shall e provided on eitl1er ide of expansion joint
I 1shy
I~
mm -Jp to 400
401 to 600 601 to 1000
Table B Hangers and Supports - rectangular horizontal ducts
Hanger Bearer Drop Roll Formed Rod
Long r Side
Cbannel ~-shy ~
---shy
Maximum ~pacing
4 52 3 _ -c Fig 15 - Figs 14 15 16 amp 2J
shy
mmm mmmm 240025 x 25 x 16 40 x 20 x 15 8 240040x20x15 40x 20 x 15 10 240040 x 20 x 1~510 40 x 20 x 15
shy
I
40 x 40 x 15 40 x 40 x 15 24001001 to 1500 I 10
Table 9 Hangers and Supports - circular horizontal ducts
Longer Side Hanoer Split Clips Maximum spacing Drop Roll f-ormed and Wrap-round Rod ~hannel Hang r
2 3 4I Fig 1920 amp 22Fig I
mm mmmm mm mm 25 x 25 x 15 IIp to 355 8 40 x 3- --1-_ 2400
2400
2400 2400
70x 6
40 x 5 SOx 5
40 x 20 x 15 40 x 20 x 15 40 x 40 15
10 10 10
356 to 600 601 to 1000 1001 to 1500
19
DW154 Spccijicutioll for Plastics Ductwork
147 Protection specification Any special coatingpaint Unless otherwise stated all support shall be finishes for protection against hostile manufactured in material as specified in this environments shall be advised by the designer
SUPPORT BEARERS
~ 14 Flg16 Inverted profile
angle I ~lIed steel
channel (alternatives) Fig 15 Profile channel (alternatives)
TYPICmiddotAL VERTICAL DUCT SUPPORTS Flat bar clipStiffening frame Outline ofinsulation stiffening frame or tlanged joint (if applicable) or flanged joint
Stiffening framc or flanged Joint
~~-I ( ee notes 10) I
r--~ -++- ~--4==J===4~---
Fig 17 Vertical rectangular ducts Fig18 Vertical circular ducts
The support bearer which depending on ducti tructural opening size could be either channel or angle section may be ll1ilised in any of the following arrangementsshy
a) To support the underside of a flat bar clip in halves (circular)
b) To support the underidc of either the stiffening frame oftbe flanged joint ofaoy duct section
c) To support either a stiffening frame Or a flanged joint below nsing drop rod srudding
20
DW154 Spediraiml for Plastics Ductwork
Arrangement of bearers and hangers (to be read in conjunction with Table 8 amp 9
wbich list material sizes relative 10 duel izes)
KEY Limits refer to actual duct size - insulation is additional - Typical
attachmentv -Atta hment t strucUlrcI to strucUlrc
I I
I - Flat Bar
I - Drop rod or - utlinc of lllddmg In ulillwn (if
applicable)
Alternative 7 drop rod or rt------------ 1 studdmg q I
I I Rectangular
ii i n 1
Fig 21 Rolled or profiled bearer Limit oncFig 19 Wrap-round hanger Limit 55 DIA
V v Drop rod orAllernaUC 1 1 tudding
drop rod or 1
-- -- 1studding and elded bas 1
I I0 -_
Limit 355 DIA Frg 22 Split clips Limit 1500 DIAFig 20 Flat strap hanger amp split clips
21
DW154 Specification for Plastics Ductwork
6PA deElned in J62 appropriate to the airflow pressure acoustic temperature and corrosion
General
15 ACCESSl SPECTION OPENINGS
151 General These are for inspectionservici ng on 1y
HVCA publication DWIl44 Part 7 - General Section 20 sets out the requirements for access applicable to this specification
152 Cleaningmaintenance Designers shall take specialist advice and then stipulate their requirements for the periodic internal cleaningmaintenance of ductwork and of the consequent need for adequate access for specialist cleaning equipment including the size type and locationfrequency of the actual access openings required
Appendix D sets out guidance notes for the consideration of cleaning access and also makes reference to the HVCA publication TR 17 Guide to Good Practice Cleanliness of Ventilation Systems which covers the su~ject
in greater detail
Note A majority of in tallations in which plastic ductwork is used are considered to have a nigb operational risk potential and provision of access should address this
16 REGULATI G DAMPERS
161 General Balancing dampers and control dampers are elements inserted into an air di tribution system or element of an air distribution sy middottem Balancng dampers permit modification of the air resistance of tbe system and consequently cbanging of the airflow rate Control dampers control tlle airflow rate and may in addition provide low leakage closure of the airflow
The deigner shall specify damper locations taking into consideration that good design practice requires a minimum of five times the diameter or width of the shortest side of uninterrupted flow between plant connections and the damper and select the damper type as
characteristics
1611 Balancing damper To achieve the required distribution of air in the ductwork system at inlets andor outlets for [hi purpose the damper blades are set and Jocked manually in position between fully open and fully closed
1612 Control damper To secure dynamic control of the air now in the ductwork system In thi function the damper will always be power actuated and may require to be modulated between fully open and fully closed and to be capable of taking up any position between these extremes In the fully open position the damper should have a minimum pressure drop In the fully closed position it will not necessarily achieve a complete shut off
162 Types of airflow control dampers Airflow dampers of various types are available for specific purposes as follows
1621 Single - blade dampers Single-blade dampers shall consist of a si ngle pi voted blade cOlllained withjn a casing or section of ductwork The blade shall be adjustable tbmugh a nominal 90 angle by means of a quadrant or similar operating mechanism Where automatic control of the damper is required the spindle shall be extended to enable a powered actllator to be mounted
Single-blade dampers shall have a maximum duct width of 400 nUll and a maximum duct height of 400 mm for rectangular ducts and for circular ducts a maximum diameter of 400 mm
1622 Multi-blade dampers Multi-blade dampers shall consist of a number of pivoted blades contained within a casing The blades shall be
22
DW154 Sedicalirm for Plastics Ductwork
adju table through a nominal 90deg angle simultaneously by intershyconnected linkage or gears connected to a quadrant or similar operating mecbanism Where automatic control of a damper is required a spindle shall be extended to enable a powered achlator to be mounted
There is no restriction on the size of duct in which multi-blade dampers or damper assemblie may be u ed Where dampers are required for blade lengths in excess of 750 mm the blades should be suitably reinforced or supponed 0
individual damper blade should exceed 200 mm in width
1623 Iris dampers Lris dampers shall consist of a nUlllber of radialty interconnected blades which open or close within a casing with duct COlll1cctions The blade shall be simultaneously adjusted by a quadrant or similar operating mechanism
Iris dampers shall be installed as specified by the manufacturers operating and installation instructions where the product is unidirectional with regard to airflow
lris dampers are available for circular ducts only in diameters up to 250 mm (it should be noted that the damper casin i appro)(imately twice the diameter of the duct)
1624 Backdraught dampers Air pressure operated uni-directional rectangular (single or multi-blade) with adapters if fitted to circular ducts
1625 Slide and blast gate dampers A damper [lsed as a shut off facility with an externaJ Lide bousing allowing the blade configuration to be fuJly inserted to fully extended for maxiDlUlll air flow
163 Construction
1631 Materials All products shall be protected against cOHosion as necessary and supplied in a fully finished condition as specified by the designer
1632 Dampers used in low and medium pressure systems The following recommendations apply to dampers forming an integral part of ducrwork with pressure classifications A and B air leakage limits
The dampers shaH be constructed to minimise distortion and prevent jammin in operation Th blade shall be sufficiently rigid to minimise movement when in the locked pOSitiOLl
The blades shall be securely fixed to the operating mechanism All balancing dampers shall have a locking device located on the outsid of the case and shall giv clear indication of the actlwl blad position All penetrations of the duct shall be fitted with suitable seals where necessary
1633 Dampers used in high pressure systems Regulatino- dampers used in duc[work sy tems to pressure cJassification C shall meet tbe construction requireshyments specified in 1631 and 1632 with operating mechanisms out of the air-stream
1634 Proprietary types of damper The use of any specific type of proprietary damper shall be confirmed by the designer In all cases proprietary dampers shall meet the relevant requirements of thi specification
1635 Damper casings Duct damper casings hall be constructed to meet th mllllmum
23
DW154 SpeciJimlioll for Plastics Ductwork
leakage Iim its sp cified for th c1uctwork ystem to which tbey are installed
In order to apply the square metre leakage calculatio as detailed in DW143 A Practical Guide to Ductwork Leakage Testing the reference casing area ball be taken as the perimeter ize of lh damper IDultipli d by the equi alent length of Imetr eg an 800 mm x 400 mm duct damper hall have a surface area for casillg leakag p donnan calculated as follow (2 x 08) + (2 x 04 x I
=24m2 casing area
Other pelforlllance ancl rating test methods for damp f and valves are specified in ISO 5129 and BSIE 1751 and are referenced belm a) Leakage past a closed damper
alve BSIE 1751 b) low ratepre sure requirement
characteri t cs BSIE 1751 c) Operational torque le ring
BSEN 1751 cl) Thermal transfer testing
BSIEN 17 I e) Reg nerated sound power levels
ISO 5129
164 Installation Dampers shall be imaalled in accordance will) any re Ievant ISO EN or British Standard 10 aJ bUT lcling regulation and national code of practice as well as the manufacturers recommendations
17 FIRE DAMPERS AND INT MESCENT SLEEVES
171 General Damper or sleeves arc requiTed on duct y~telll where the designer has -tjpulated the
duct wiU penetrate a fire compartment in the majority of application tbermopla ti ductwork is ugtecl where contamlDated corro ive or otherwise exceptional fumes are concerned it is preferable to use tire damp r which are externalJy mounted ie of the intmnescent operated crush typ
24
72 Fit-e rating The damper assembly should have a fUT
resi tance ratin o equal to that of the fir ban-jer it penetrate and ball be fire tested and rated to the timetemperature curv of B 476 Part 20 and 22
173 Intumescent sleeve At the time of writing this specification qualified test results were available for rectangular dampers and circular dampers up to 55 mm diamet r Manufacture have indicated that they are able t provide speci fications for other size and diameters This infonnation should be confirmed b th de igner Various type are available includino
tho e incorporating ruechanical closing plate and those operated anI by expanded iJllUme c nt media
In all ca es fire damp rs and intnmeBcen leeves shall be supplied and in taUed in
accordance with the manufacturer iJlStructioos and COSHH a essm nt
174 Other types Fire dampers of mious types are availabl for specific purpose~ ee HVCA publication DW144 The de igner should )lot (hat materials for con lt1Jction bould be uitablc for the par1icular application
ALL C SES FIRE DAMPERS AND fNT MESCENT SL _VES SHALL HE S PPLTED AND INSTALLED IN A ORDA CE WITH Tf--IE MANUshyPACTURERS STRUCTTONS AND COSHH ASSESSMENT
18 FLEXIBLEEXPANSION dOINT CONNECTIONS
181 General ploperties Tbe material u ed for flexibleexpan ion iojnt~
mu t meet the design r requirements for temperature air pressllrelfe resistance applicable to pl astic duct sy tem vibration and noi e br akout when incorporated into a jointconnection and shall comply ith lh standard of air-tigbtne specifi cl for the duct work sy tem of which it fOlms part (See Figs 23 24 5 26 27 amp 28 for typical con truclion clelai Is
DW154 SJecilimtol for Plastics Ductwork
Expansion joints
Fig23 Moulded bellows type (rectangular and circular)
Fig24
~F aiblc sleeve
__ liding sleeve
~~~~
Sleeve type (circufar)
Fig 25
AIRFLO
COnlinuou~
weld~
Flexible Iceve
PV A HOWN pp SE BACKING FLATS AS FIG 2
Sliding lee c Co1linuou
weld
Flanged sleeve (rectangular and circular)
25
DW154 Specificatiol for Plastics Ductwork
Flexible con ections
Fig 26 Flexible sleeve with clips (UPVC and PP)
--__ Flexible I eve
I
I
I CODn clioD to plant ~
Band clip
Fig27 Welded flexible sleeve (UPVC only)
Plastic)sed PVC slceve ~-- onll11uo1sly welded
onrreclion to planl ~
Fig28 Flanged flexible connection (UPVC and P )
t sp dally moulded flexible flanged connCClitlll
boil
C)nneclion to plant ~
26
DW154 Specificotiol for Plastics Ductwork
182 LOClt1tion Flexible joint are typicltllly lIsed at building expansion joint and fan inletsoutlets Any others required should be indicated on the de ign drawings Care should be taken to maintain alignment across jointsconnections
183 Length Flexible Jomts shall be kept as short as pra middottieable above a minimum eft ctive length of SO mm In no ca e shall a flexible joint exceed 250 mm in lengtb
184 Connections to rectang a ducts With flanged rectangular connections Ule tlexible material shall be held in pLace with flat pIa tic strip of not less U1an 6 mm thick ltlttached to the flanges using uitabJe fixings The more heavy weight type of fleAible mateLial may also be obtained formed into a channel ection with corners fitted to give a neat air tight j int For pigot connections the Be ible material shall b held in place with flat pIa tic trips n t less than 6 mm thick
t 85 Connections to circular ducts With tlanged circular connections the flexibl material shall be held in place with flat plastic backing strips or proprietary clip bands with screw or toggle fast ners
186 Welded flexible connections (Rectangular and Circular) Where the parent and llexibl material are from imilar ba ed products they can be joined to the duct u ing the welding method described in Section 823
19 PROTECT VE FINISHES
191 nles otherwise stated all ductwork shall be mallllfactured in mat fial as pecified in tbis specification Any special coatingpaint fmishes to be provid d by the duct work contractor sball be advisd by th de igner
20 CONNECTIONS TO BUILDING OPENINGS
201 Fanning and finishing building op nings are not the repoJlsibjlity of the duftw( rk contractor and the note that follow are for guidance purpo e only
2011 Openings in brick block or concrete walls shall have inset frames to provide a suitable means of fixing grille louver masking flanges or the tlanged ends of ductwork The illset frames shall be conslnlcted to maintain the structural int grity of the wlll and where applicable cavities shall be suitably lined
2012 Openin s in dry linino partItIons shall have inset frames a 2011
2013 Openjngs in cladding walls and roofs shall have flaoged leevesframes to provide a suitable means of fixing a 2011
2014 Horizontal and vertical opening xposed to oLltside atmo phere hall
be provided with a suitable weathering fini h at the external face especially where profiled cladding is used
2015 Timber framed op nings are not permitted In fj re compart ment barriers
202 Ductwork connections to building openings hall have a flange of suitable profile to permit practical fixing to the openillg frame In selecting the profile consideration shall be given to Tabl~s 2 and 10 in this specitication relating to duct ize and rating Gasket strip or sealant shall be ltlpplied between the tJaoge and building op ning frame
21 DISCHARGEEXHAUST TERMINAL
21 Tbese shall be vertical open ended and designed to meet and comply with current r gularions on contaminated flue The designer hall ensure that the de ign and perf rmance i suitable for its intended purpose Examples of some typical terminal designs are SbOiD in Figbull 102 10 bull 104 amp 105
27
DW154 SpedjimioTl for Plastics Ductwork
22 THERMAL INSULATION
221 The provision and application of thermal insulation to ductwork is not the responsibility of the ductwork contractor
222 Where ductwork is required to be preshyinsulated the specification should be agreed with tbe designer
223 Where the temperature of the air within the duct promotes condensation on the exterior surface of the duct and cause moisture penetration througb the thermal insulation vapour scaling may be required and in this case the most important requirement is to limit penetration of the seal
The extent of any vapour sealing of ductwork thermal insulation and the support method to be u ed must be clearly pecitled in advance by the designer
224 For detailed information on the thermal insulation of ductwork reference should be made to BS 5422 1990 which covers the specification for thermal insulation materials on pipes ductwork and equipment (in the temperature range -40degC to +700degC) and BS 5970 1992 which is a Code of Practic for Thermal Insulation of Pipework and Equipment (in the temperature range -lOOdegC to +870degC)
23 FIRE RETARDANT FINISHES ON PLAST C DUCTWORK
231 The designer should note tbat ductwork constructed to DW154 has no teted fire rating or information see Appendix C
24 REINFORCEMENT OF DUCTS WITH GRP LAMINATE
241 General Where ductwork is required in larg T izes than are covered by Tables 2 4 6 amp 7 or with the increased strength sometimes necessary for industrial use external reinforcement is normally pwvided by applicatioD of glass fibreresin laminate
GRP systems will bond satisfactorily with standard UPVC sheet but for pp it is
nece sary to use a specially prepared sheet with a glass fabric backing incorporated dOling manufactllfe
The detailed techniques of fabrication using GRP are outside the scope of this speci lcation but the following notes are offered for guidance of ductwork fabricators
242 Materials
2421 Quality The laminate is made up of polyester resin complying with BS 3532 and glass fibre complying with BS 3496 or BS 3749 The nominal ratio of resin to glass fibre should be 7030 by weight
2422 Minimum properties The laminate shall comply with the followiog mini mum pbysical properties
Tensile strength - 70 MNm Tensile modulus - 7 Gl m Flexural strength - 140 M Im Bond strength (hetween laminate and substrate Not less than 7MNm Bmcol hardnes Not le s than manufacturers specification
The GRP reinforcement educe the expansion of the parent material but the resultant stre ses arc well within rhe strength of the bond However the Iinear thermal expansion curve shown in Figs 34 amp 35 will serve as a guide
Surface resistivity electrkal propcltles and acoustical propertie are similar to the relevanl unreinforced materials The fire retarding properties of GRP may be improved by the use of specialisl laminating resin
2423 Forms available GRP Laminate should be built up from the separate materials ie resin aod glass fibre in the form of chopped
I strand mat or spray ravings
28
DW154 Spcification for Plastics Ductwork
2424 Workshop conditions Polyester resuls are sensItIve to lmperature and the workshop hould b maintained at a temperature of herween 20deg and 25degC HiOh relative humidities and damp onditions should be avoided A good rate of air change must be pro icled pJeferably by m chanical ventilation
2425 Storage of materials Resin and urin o agents shouJd be stored in dark cool condirions away from the working area and in confonnit with statutor requireshyments for tJle middottorage of flarmnable liquid Because of Ule Limited torage lif of the unmixed resin and curing a eot mal lials ~hould be ch eked before use to enLlfe that they are within the manufacturer pe ified sh If life (usually ix month from the dm of manufacrure)
Glass fi re should be stored separately und r clean dry conditions
243 Surface preparafon
2431 UPVC To achieve the specified bond strengtll the urface to which the GRP is applied mut first be thoroughly cleaned and then etched either by mechanical means or by the use of a suitable solvent
2432 pp with glass fabric backing To achieve the specified bond middottrength the fabric backing must be thoroughly impregnated Witll resin
244 Mixing the materials for use The re in 1 a three part mix compri lng base I sin hardener and accelerator The manufactur rs pecj[ied proportions are critical and th llUxmg sequenc pecified must be meticulously foUowed
The resin has a very limited life after mixing and before u e It is dependent on the characteri tics and bulk of th resin the alllount of hardener the degree and method of acceleration and the workshop onditions
245 Methods of application
2451 General The mixed resin may be applied by hand or b pray c1epoition The operation must b completed within the gel time of th y tern and tbe laminat fully cOI1olidated to achi v the phy ieal properties pecified
2452 Hand lay-up The duct surface i coated by hand with resin Llsing a brush and a mar of gla fibp orked in until full consolidation achieved Th proc is repeated untiJ th requird thicknes i obtained
2453 Spray depo Won The duct surface is coated WiUl re in by spray gun with the chopped glass roving added through a separate nozzle The full thickne i obtain d in layer with con olidation of each layer by hand roller
246 Construction
2461 General M ini mum COllst ructional requireshyments are pe itied ill Tabl 10 for rectangular and Table 1J for circular dUClS
2462 Joints and stiffeners Fig 29 30 31 32 amp 33 hoI TOSS
joint and tiffener for reinforced UPVC and PBPP duct
247 Worki g practices The fabrication of ductwork pecifiecl ill thi document i not affected by the addition of GRP
29
DW154 SfJcdJicatiOt for Plastics Ductwork
Table 10 Minimum constructional requirements shy
Longer Side Minimum Sheet Thicknes and
GRP Reinforcement
UPVC FBIPP 1 2 3
mm mm mm Up to 1000 3 plus 3 plus
06 kgm2 06 kgOIl GRP GRP
1001 to 2250 45 plus 3 plus 06 kgm 12 kgm
GRP GRP
2251 to 3000 45 plus 6 plus 12 kgm 12 kgm
GRP GRP
Cross Joints
UPVCFBPP 4
mm socket amp spigot
as Fig 30 or flanged as Fig 29
75 x 9 flange welded on both sides as Fig 29
75 x 9 tlange welded on both sides as Fig 29
rectangular GRP reinforced ducts
SlifTeners Maximum Spacing Between
JointsSljffeners UPVCIFBIPP UPVCFBPP
5 6 mm mm
75 x 9 flat 800 as Fig 31 or
50 x 50 x 5 plastic or MS inverted angle as Fig 32
or tormer as Fig 33
75 x 9 flat 600 as Fig 31 or
50 x 50 x 5 plastic or MS inverted angle as Fig 32
or former as Fig 33
75 x 9 flat 600+shyas Fig 31 or 50 x 50 x 5 plastic
or MS inverted angle as Fig 32
or former as Fig 33
Note 1 On rectangular duct up to 400 mm longer side no stiffeners are required 2 Applies to Tables 10 amp I I For COlJstructional operating temperature limits refer to Part 2 clause 5A 3 Tables 10 amp II apply to all pres ure classes up lo ]500 Pa
Table 11
Diameter
1 III
lJp to 1000
1001 to 1750
1751 to 2500
Minimum Sheet Thickness and
GRP Reinforcement
UPVC FBPP 2 3
mm mm 3 plus 3 plus
06 kgm 06 kgm GRP GRP
45 plus 3 plus 06 kgm2 18 kgm
GRP GRP
6 plus 6 plus 12 kglm2 18 kgm1
GRP GRP
Cross Joints
UPVCFBPP 4 III
socket amp spigot as Fig 30 or flaoged as Fig 29
75 x 9 flange welded on both sides as Fig 29
75 x 9 flange welded 00
both sides as Fi 29
inforced ducts
Maximum Spacing Between
JointsStiffeners UPVCIFBPP
6 mm 2400
800
600
Stiffencrs
UPVCFBPP 5
mm 50 x 9 flat as Fig 31
75 x 9 flat as Fig 31 or former as Fig 33 75 x 9 tlat as Fig 31 or t()rmer as Fi 33
ote On extruded tube tip to 600mm diameter no stiffenergt are required
30
DW154 Specificatioll for Plastics Ductwork
G - Cross joints and tiffeners
Fig 29 Flange Joint Fig32 Stiffener shy inverted angle
M artiPfCuQkbdd erttpObri) Wl111 RP tlddtlt
_- GRPloliu] lh~
Fig 30 Socket and spigot joint Fig33 Stiffener shy use of former
Fig 31 Stiffener Flat
I Pv FlPP ~ ~lmJaDUA1) d
OMrlQ rrnall 1( tQlS
25 STANDARD COMPONENT DRAWINGS AND ABBREVIATIONS
251 The illustrations in this section not only highlight where applicable geometric limjtations for the de ign and manufacture or ductwork components but also recommend
standard drawing representation terminology and abbreviations for both duetwork components and some of the more commonly used ancillaryplant items
252 Designers and surveyors should note that bills of quantities should provide a full description
3)
---
v
DW154 Spcc(fim(ml for Plastics Ductwork
Fig 34 Linear Thermal Expansion
u c 0 N ro 0)
b 0)
S
sect0
5 oS cl) 0)
~
on ~ ltl
c U
-30 -20 -10 0 10 20 30 40 50 60 70 80 90 TEMPRATURE C
~ V
-
~~c_ ~
~V
V ~
-7 ~
-- ~V ----
v
-6
+14
+12
+10
+8
+6
+4
+2
0
-2
--4
ig 35 Typical Design Stress tor UPVC and P
7
6
r shy 5E
-c E----0 4t) VJ 0)
ci5 0Jl 3
~
0)
Cl
2
1
o
UPVC
1
000
1
1
pp
- r-- shy r----- shy - t--shy I
__0
-30 -20 -10 0 10 20 30 40 50 60 70 80 90 TEMPERATURE C C
Note Figso 14 amp 35 shaded area refers to GRP reinforced duct
32
DW154 Speciicfltirm for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - REC ~NGULAR
Splilt~r Posilion W-mm pliucr
A B c 40]--QOO 1 W - -
601-1000 1 W4 Wf2 -
1001-1800 3 WI W3 W2
FIG DRAWING DETAfiS
tU]36 ATI Straight Duct with socket and spigol joint
rn [037 Straight Duct with flanged joints
[I []38 Straight Duct with flanged joints
rkJ Short Radius Bend
39 Applies to any augl and for duct up to 400 n11n wide
Minimum (I1m31 radills = 100 mm
Medium Radius Bend (a illustrated)
[kJ Applies to any angle
40 Long Radiu Bend Similar but radius = W
Throlll radius = W2 Applies to any angle
- Short Radius Bend with plitlers
I -shy -shy u co - t lt Li--_ 41 t 0 ~ I I I
~ I
L 1W
Minimum waal radius = 100 mm Splitters not required in bend angle less than 45deg
42 QJ1 Square Bend with turning vanes ij
3
DW154 SP(L~ficatioll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - RECTANGULAR
FIG DRAWl G DETADS
43
~
I v
L L Radius Tee with internal deflectors
44
~ Radiussed Twin Bend
45
Imiddot
er Swept Branch
46 U-
Sqoare Tee with Turning Vanes
47
~ f
Breeches Piece
48 0 y l Piece
34
DW154 Specificatioll for Plastics Ductwork
STANDARD COMPONENT RAWINGS - ECTANGULAR
55
54
51
50
53
52
49
FIG
~MX
RAWlNG
DmiddotMAX
EfjMAX
Minimum throat rndius = 100 mm
Rectangular shy Round Transformatioll
Eccentric Taper 225deg max in either plane Spliller are required for angles greater than 225deg and hould bi eet the angle between any side and duct centreline
DETATLS
Angled Offset
OUset Taper Splitters are required for angle greater than 22 0
and shoold bi eet the angl between any side and dUCI centrelinc
Mitred Offset
Concentrk Taper 2250 max in ither plane SpUtters are required for angle greater than 225deg and should bisect the angle between any side and duel c ntreline
Radiussed Offset
35
DW154 Splcilcuthm for Plastics Ductwork
STANDARD COMPONENT DRAWINGS ~ RECTANGU AR
Branch ducl DimCllsions widlh (W) (A)
urnl mm up lO 200 75
300 100 400 125 600 150
Ocr 600 200
FIG DRAWlNG DETAILS
56 poundplusmni~~ Rectan~lar - Flat Oval Transformation
57 [ Square Branch
58 er Angled Branch
Branch dUCI Dimensions wfdth (W) (A)
[- mm mm59 3shy Shoe Branch Up (0 200 75
--shy AIshy + 300 100
400 125
450 MAX 600 150
Over 600 200
Branch duct DimensIOn
rP X width (W) A)
60 - 1--shy _
~ mm mm
Bell Mouth Branch pto 200 75 300 100 t 400 125
600 150 Over 600 200
0=0 61 -
~ Bell Mouth
- shy T 4-5deg M x
--I 1-shy
TJ
62 X I ] I
Tele-scopic Joint I Illustrated with flangeL
X63
SBD Single Bladed Damper
36
---
DW154 Spedicatioll for Plastics Ductwork
STANDARD OMPONENT DRAWINGS - RECTANGULAR
DRAWING DETAILSFIG
64 on-Return DamperNRD shyshy
shyXbull
Multi-Leaf Damper Can be piggoted or flanged oppo cd or parallel blade
Alternative controls areshy
q p [gtshy
J HD65 Hand
~MD otori ed
PO Pneumalic
L-lt
l 13G 66 Blast Gate DamperX X
FireSmoke DampersSleeves
211r Ratinggtshy----
L_-
---
----
r----
Ir-- shy
IL- _-l
2hr
With i tallation frame
67 41 r Rating
4hr
Smoke damper SD
Intumc cent Sleeve L-d
37
DW154 Specijicutiolt for Plastics Ductwork
FIG
68
69
70
71
STANDARD COMPONET DRAWINGS shy REC ANGULAR
DRAVING DETAILS
gtshy Access Openings
AP 6 Access Panel - Rerno able
w [ ~ Access Door - Hinged
I ~le Inspection Cover
le -I reg -lt
~X X Flexible Connection
~ Drop Cheeked Radiussed Twin Bend
U Drop Cheek Bend
I
72 Air Flow SymbolX
38
DW154 Specifim[ioll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - ECTANGULAR
FIG DRAWING DETAILS
73
74
75
76
77
Q
Q
rp---t
~
V- I Ir---I
JL --11
THE ABOVE DETAILS TYPICAL PLENUM
Air Terminal Plenums
Plenum with side connection
Plenum with top connection
Cover plate with connection
Special plenum with connection
elescopic conn ction in direction of air flow
39
DW154 SpecijicotiOll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG
78
79
80
81
DRAWING
-23~---pound3-(MALE) (FEMAJE)
-t=j--_j(--d-shy
--L
~ THROAT RADI S= D AS T NDARD
e ~
THROAT Rjf)lU = D A MU)
DETAILS
Straight Duct With male and female connectors
Straight Duct With flange joint and slip joint
Bend MouldedIFormed Applies to any angle ego 30deg45deg60deg90deg Medium radius bend as illustrated Long radius similar but throat radius 0
Segmented Bend 90deg four section minjmum as illustrated
Other Angles 60deg = 3 sections 45deg = 3 sections 30deg = 2 sections
I
i
40 shy
DW154 Speciicafinll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG DRAWING DETAlLS
82 Segmented Twin Bend Radius = D2 max
May also be fabricated from tube
83 Equal Tee MouldedIFormed
84 -~ 1in Bend MouldedIFormed
85 Taper Concentric 1 0 as iUu trated Eccentric 30deg iJJcLuded angle
86 Short Taper
41
DW154 SpcUicatol1 for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG DRAWING DETAILS
87 30 max Offset
Angle Branch
Bran h dUCI Dimcnsions dia (D) lA)
Shoe Branch mm mm 88 Cl
Off rectanguJur Up 10 200 75 lOO 10 400 125
- 00 150 Over 600 200
Bl1IllCh duct DimenlOns din (D) (A
~-$a-Conical Branch mm mm
89 Also acceptable with Up 10 200 r
full conical surface 300 10
400 125
END VrE -shy 600 150 Over 600 200
90
m 75
100 12 150 200
mm Up to 200
_ 300 400
600 Over 600
iUtred Branch
Shoe Branch
J-L----U ~ Bell oulh Branch
ENDV1EW
93
92
91
42
DW154 Specificatiol for Plastics Ductwork
STANDARD OMPONENT DRAWINGS - CIRCULAR
FIG
94
DRAW G
I
~ 30deg 090deg
Breeches Piece
DETAILS
95 amp-----~ Blank End
~-----p Multi-Leaf Damper Can be piggolcd or fianged opposed or parallel blade
Alternative controls areshyri=-+- L-T~
I
---
LT~
I r- -
-+1
J HO Hand96
bMD Molori cd
PD Pneumatic
tl-shy bull
Single Bladed Damper 97 ~ saD
on-Return Damper Vertical application only 98 m~D
43
DW154 Sf1tcificatioll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG
99
100
101
102
DRAWING
$ I-
2hr
1 4hr
SD
~v I I
CO TINENTAL COWL
DETAILS
Iris Damper
Fi reS moke Dam persSleeves
2hr Ratillg
With installation frame
4br Rating
Smoke damper
Intumescent Sleeve
Access Openings
Access panel - removable
Access door shy hinged
fnspection cover
Discharge Continental Cowl
44
DW154 Sp(Cii(ltJll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
DRAWINGltIC DETAns
-
I
I
~
I I I High Velocity Discharge Terminal 103 I
I
I I
J I I 1 ~--
Offset Stack Discbarge Terminal 104 1
~ I e --(-
I
N
I
I
I~
I I Vertical Oischarge with Weather Cowl 105 I
--1--1 I
I
GAPI I
RTl AL DISC) lARGE WITH W ATIIER COWL
45
DW154 SpecUicatoll for Plastics Ductwork
STANDARD COMPONE T DRAWINGS - PLA TEQUIPMENTIMISCELLANEOU
FIG DRAWING DETAILS
106 ~~~ Rectangular Attenuator
107 ~- Circular Attenuator
108
~ Beod Attenuator
109 J ~(f) Heating Coil
110 J ftte Cooling Coil
III Jc[ Electric Heating Coil
112 X F
Humidifier
113 [H XX Axial Fan
114 ~fB1famp Noo-standard Ductwork Cross hntchillg (of any separate type) indicates by reference to a key any non DVil54 ductwork system
115 2llIIIIJIIIIIll Flexible Ductwork
46
DW154 SJeCUicll(iol1 for Plastics Ductwork
TABLE 12 - STANDARD ABBREVIAT ONS
ABBREVIATION FLL
AD Acces Door
AFF Axial Flow Fan
AHU Air Handling nit
All Aluminium
AP Acess Panel
AT Attenuator
AV Air enninal Unit
BE 81ank nd
BQ Blast ate Damper
CC Cooling Coil
CF Centrifugal Fan
CTA Cross alk Attenuator
CVU Constant Volume Unit
DP Drain Point
EEC Electric Heating Coil
El Expansion Joint
FAl Fresh Air Inlet
FA From Above
FB From Belo
fBPP Fabric Backed Polypropyl-ne Sheet
Flexle Flexible Connection
lexfD Flexible Du t
C False Ceiling CO an oil Unit
fD Fire Damper
FFL Finished Floor Level
FJ Flanged Joint
FOAM Rigid Polyurethane Self xtinguishing Foam
FOB Flat on Bottom
FOT Flat on Top
GAM Galvanised after ManufacttrJc
GRP Glass Reinforced Plastic
GSS Galvanised Sheet Steel
HC Heating oil
HD and controlled Damper
HH Hand Hole
HL High Level
HVD High Velocity Discharge
IC Inspection Cover
ID lri Damper
IFS Intumescent Fircleevc
47
DW154 Specification for Plastics Ductwork
TABLE 12 - STANDAR ABBREVIATION CONTINUED
ABBREVIATION
IU
L
tv1D
MS
NRD NTS
OBO
OE
PHD
PD
PP
PP
PRD
PVC
RFC
RSC
R
SBO
SO
S1 TST
SSL
TA
TB
TO TJ
TP
TV
TV
OS
UPVC
S
V
VAV
50 RSA
FULL
Induction Unit
Low Level
Motor controlled Damper
Mjld Steel
on Return Damper
at to cale
Opposed Blade Damper
Open End
Parallel Blade Damper
Pneumatic controlled Damper
Polypropylene
Self xtinguishing Polypropylene
Pressure Relief Damper
Polyvinyl Chloride
Rolled Form Chamlel
Rolled Steel Channel
R fUnit
Singl Blade Damper
Smoke Damper
Slip Joint
Stainl t el
tructural Slab Level
To Ab vc
To Blow
Top Down (In Direction of Flow)
Telescopic Joint
Test Point
TU111iog Vane
Top Up (In Direction of Flo )
Voles Otherwise Stated
Unpl3sticisecl Polyvinyl Chloride
Underside
Ultra Violet Light
Variable Air Volume
Rolled Steel Angle (Vith Size)
48
DW154 SJeriiflllioll for Plastics Ductwork
A2 DUCT PRESSUREAPPE DXA Ductwork con truct d to DWIl54 will bebullbullbullbullbullbullbullbullbullbullbullbullbullbull
Air Leakage From Ductwork To be read in conjunction with DW143 A practical guide to Ductwork Leakage Testing
CAUTION As highlighted ill both this docul1lenr and DW14 I lot ellough emphasis can be placed 01 the fact that except for high pressure class C the much more stringent ductwork constructional standard brolght about b the general acceptance of DW154 have irtlally negated the requirement for leakage-testing It is essential lO realise lhat except where it is mandatory this doclllllelll is nOl an endors ~lIlent of the rourine testing of ducts bllt purely a guide to outline the procedures for cononnity with the air leakage limits ill Table l Where the specified methods of assembly and
A3sealing of dlcls are u ed a vi ual inspection wil ordinarily sl~fll e for ver(iatioll of a well engineered and a ceptahfy airtight COl1strucrioll WHERE NOT MANDATORY DUCT LEAKAGE TESTING IS GENERALLY AN UNJUSTIFIED AND SUBSTANTIAL EXPENSE
A1 INTRODUCTION L akage from ducted air distribution systems is an Lmportant consideration in the design and operation of ventilatjon and air conditioning middotystems A ductviork t)ystem tbat ba limited air leakag within defiucd limits wiH cnsUft
that tile design characteristics of the sytem can be maintained It wilJ also ensure that energy and operatLonal cosb are maintained at optimum levels DucLwork constlucted and Ulstalled in accordance with DW154 should minimise a level of air leakage that it) appropriate to tll operating static air pre sur in tile system
A4However it is recouuised that tbe environment in wtJich middotystems are installed is not always conducive to achieving a predictable level of quality in term of system ajr leakage and it is therefore accepted that designer may sometimes require tlle ystem to be tested in part or in total It should be ecogni ed that the testing of duct systems add a ignificant cost to the installation and incur some extra tjm within the programme (Se 47 and 64 re mandatory te-sting)
manufactured to a structural standard that is compatible with the system operating pressure There are three classes of duct con truction to eorre pond with the three pre ure clas meations Class A Lo pressure ducts suita le for a maximum positive operating pressure of 500 Pascal and a maximum negative pressure of -500 Pascals Class B IVledium pressure ductmiddot suitable for a rnaxilnuJJl positive operafjn o pressure of 1000 Pascals and a maxllnum negative pre sure of -750 Pa cal Class C High pre sure ducts suitable for a maximum po ilive operating pressur of 2000 Pa cals and a maximum negativ pres ur of -750 Paltcals
LEAKAGE FROM DUCTWORK Leakao-e front pia tic air ducts occur at the joint~ and is therefore proportional to the total surface area orthe du twork in th system Tb level of leakage i imilarly related to tIle air pres ure in th du t system and whilst there LS n precis formula for calculating the level of air los it i generally accepted that leakage will increase in proportjon to pressure to rbe pOvver of 065 The effect of air leakage from high pressure velocit ductwork is critical tn terms of system perfomlan dege energy consumption and the risk of high frequency noise as ociated with leakage These problems are le critical with medium pressure 10 ity systems but should be con idered Low pres mevelocity ducts present the lowe~t
ri k in tenn of tbe effect of leakage on the operation of the s stern
SYSTEM LEAKAGE LOSS As there i no di ct relatLonship between th volume of air conv yed and the surface area f the ductwork sy tern required to match the building configuratmn it is difficult to express air leakage a a percentage of total air volume Similarly the operating pressure will vary throughollt lh 3 system and a leakage is related to pre me the calculations ar comple However it is generally ac epted tbat in typical good quaJjty systems the leakage from
49
DW154 Specificatioll for Plastics Ductwork
each class of duct llnd r operating condition will be io the region of CIa S A low pressure 6 Clas B medium pres un 3 Clas C high pressure 2
A5 SPECIFYING AIR LEAKAGE TESTING Re peeting both the co -t and programme implications a sociated with te ling du 1 for leakage the designer may for example indicate that a particular system is te ted as follow
a) High pressure ducts - all tested b) Medium pr ssure duets - 10 of the
ductwork shall be s eet d at random and tested
c) Low pre sure - unte ed In any case where a random te t i elected for medium pre sure ductmiddot the followin c1au~e is suggested for inclusion by the de ign r
The designer hall elect at random a maxirnwlI of 10 of the dUCl system to bt tested for air leakage The duct hall be tested af the pressure recommended in Table J3 for the assifi atiol for the ectiol1 of the ductwork that is to be tested The tests shall be carried Ollt as the work proceeds and prior to the application of thermal insulation In the event of test failure of the randomlY selected section the designer shall have The right to select two La1her e tiolls at random for resting Where succes ive failures are identified there shall be a Tight to require rhl COl11raCWr 10 apply remedial attention to the complete ductwork system Th contractor shall provide documented eviden e of the calculalions used to arrive (1
the allowable 10 I for the section to be tested and the client or his agent shall willess and sign the results of the test
able 13 Air leakage rates
Maximum leakage of duct work Static
prcssUft Low-pressure edium-prc-sure I Iigh-prebull me diJfercntial Class A Class B Class C
1 2 J 4 Pa Litres per second per quare metre of surface area 100 054 018 ZOO 084 028 300 110 037 400 132 044 500 153 051 600 058 019 700 064 021 800 069 023 900 075 025
1000 080 027 1100 1200 1300 1400 1500
029 030 032 033 035
1600 1700 1800 1900 2000
036 038 039 040 042
Note Recommend d mean test presures are highlighted iD bold type with the actual selection being left to tll test operator
50
DW154 Sfeeiieaioll for Plastics Ductwork
A9
A10
and air leakage classification for the y em under test
DESIGNERS CALCULATIONS The designer can middotaJculate with reasonable accuracy the predicted total loss from a ystem by
a) Calculating the operatin presure in each ection of the sy tern
b) Calculating the surface area of the ductwork in each correspondin pre lire s ction
c) Calulating the allowabl~ los at the operating pressure for each ection of the system (see table 13 for allowable leakage figures)
VARIABLE PRESSUR S IN SYSTEMS De igner can achieve significant co t saving by matchina operating pressures throughout the system to constmctional standard and appropriate air leakage testing eO the practice of specifying construction tandards for whole duct sy tems based on fan discharge pre sure may incur unnece sary costs on a project For example ome large sy terns ould well be classiC ed for I akage limits as follows
Plant room risers CJas C Main floor distriblltJou CIa B Low pre sure outlets Cla A
A6 SPECIAL CASES There may be ~itLlations on a project where circumstance dictate thal pecial consideration be given to containing air loss s eg a long mn of duclwork may incur a di -proportjonate level of air 10 s In ca es such as thi example the designer can specify an improved tandard of airtighmess ie 80 of alJo~able 10 s for la B Ju ts The designer sbould not specif a CIa C t sI at CIa s C pressure for a CIa s B ducl
A7 SUGG S ED RANGE OF TES ING
A8 TESTING OF PLANT ITEMS Items of inline pJant (eg Fig 106 to 115) will not normaUy be included in an air I akage test The dllctwork contractor may indud such itelllS in tbe te t jf rh quipm ot has a certificate of COnfOlnlity for Ihe pres ure clas
bull High pressure duct bull Medium pre sure ducts bull Low pre sur ducts bull Exposed extract syst ID bull Ceiling void extract
systems bull Secondary ducts from
VAV or fan coil units bull Flexjble duct bull Final connections and
branches to grille and diffusers
100 test See A5 Untested UDt sted
Untested
Untested Untested
Untested
SI
i
DW154 SJecijicafion for Plastics Ductwork
ig 116 Permitted leakage at various pressures
Leakage in litres per second per square metre duct surface area
Vgt
o ltgt 0 ltgt N
ltgt Cgt
0 0 cc
0 0
~
g =
g ~
c 0
J
ltgt 0 I
~ ] tn
ltgt ltgt
In ol
~ 0 ~ 8 ~
~
c ltgt ltgt
~ CJ
~ ~ ~ ~ 8
0shyij
~ ~ ~ t
ltgt ltgt 00
l
~
~ Q
c C
~ rshy
e ltgt
I 1
I Cgt ltgtv
c Co ~
~~ ~ 10
I
0 Cgt
fJshyq 410 ) 1 ltgt
ltgt N
~ shy ltgt ltgt
~ I 1
c
52
DW154 Specificatio for Plastics Ductwork
Example of a completed test sheet Test No
General
Name of job N~ jC43Pt(r2lef Building Repound ~(~~0
Part 1 - Physical details
a Section of duct work to be tested ~(diffPIfff~el1f3rd Floor
b Drawing Number g91~~ c ssure aSSJ L atlOn V~Jl~IRfYgtg~~lPre Cl T Class C
d Test static pressure -(9 raErq~ ~~~~-~~J~~~ ~~ ~~~~ll
Leakaoe factor 9~-tre3$ecMz I OM REFTOTABLE 13)e b bullbullbullbullbullbullbull
f Surface area of duct under test Q~tJJItetre$ CPROMCALCU TIO BELOW)bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull ampampamp bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull
g ]Vlaxi mum permitted leakage -~ (~i~~0 ~~r~~ ~~~l-~-11~ ~~~Q
Part 2 - Test particulars
a Duct static pressure reading 9QFt~q~ ~ middot~~~1 ~~
b Manufacturer and type of liow measuring d vice (-~~~cJ~Y-9Q7EYg c Range of measurement of now measuring device QtP)OQ~(e~~~0I~~~~1~I~ ~~~~~~W~
d Reading of flm measurin o device pmiddot IFROM RIO)ftscag ~
I (DERlVED [ROM CHART SUPPUED WITH RIG US 0 ud)1e Interpreted air flow leakage rate ~(~~~f~~~ (~l~~~~~~~~~~~~~~~~~I
f Duration ~~~~~norn~allY l~ lnil1Ut~~d~~~ it1~ W~ Date of test ~(lITled ut by Wltll s ed by ~ ~
(~lJ MIJLrr) (Si~rrfltJUYJ
Printed Name 1~g0f~ Printed Name ~~Y~9~ and Company 7jl~~~~~( UJd CompanY AB COII$Itallt8
Width and depth or diameter
Periphery ength Area
millimetreS millimetres metre qL1are metre
800 x 750 3100 1755 5440
600 x 650 2500 557 1193
300 x 300 1200 120 144
305 din 958 700 670
250 dia 785 450 353
TOTAL 8000
53
DW154 Specijilarion for Plastics Ductwork
pA XB
Guida ce No es For he ransport Handling and
Storage of uctwork
avoid damage to adjacent duct panels In somc ca es particularly on con acts calling f r repetitive sizes the use of timber jigs and spacers may be justified Where reduced bulk and greater protection are major factor such as consignments for export transporting ductwork in L shape sections may justify the increa ed ite as embly co ts
It is recommended that before a contract is finalised that consideration is given to the subject of site acces material handling and storage as tbcy havgt a strong influence on the cost efficiency of the overall activity of ductwOlk installation
B3 Handling To minilnise th risk of damage duct sections should be clearly identified and deliveries to site should be closely linked to the installation programme so as to avoid accumulation of
B1 Storage and Handling of Ra Material Material should be stored in suitably designed racking out of direct unJight Where possible the e racks should be metal to earth Edges of cut she t may be harp and protective gloves are advised Wearing teel toe-capped boots is recommended Most pIa tic sheet is manufactured with smootb mfaces andor is suppLied with protective coating Care must be taken to prevent accidental lippag of stacked materials Beiuoshy good electrical insulators the movement of stock unless earthed will allow the build up of stati All stock shapes are chemically stable at normal temperature Whil t some raw materials used in their manufacture may themselves pre ent a toxic hazard once incorporated into the lOck bape they no long r constitute such a hazard and no dermatitic bazard are known nor are any
unfiJied ductwork and minimise double handling It is important to recognise that ductwork panels joint and corners arc susceptible to damage and care must be taken wheu band ling such material through a site During handling individual item of duct work may be liable to light cross sectional deformation until thev become an integral pan of a completed ductwork system Whilst this may temporarily detract from its intended appearance thi deformation will not have any detrimental effect on the functionality of the finally a semblecl system Installation of duct work and asociated plant items ill illevitably involve manual handUng The responsibi Iiry of employers and employees to a ses the risk of personal injury during mallual handling operations is et out in the HS E publication L23 Guidance on Manual Handling Regulations 1992
environmental problems expected 84 Site storage
B2 fransport Large capacity vehicles with high-sided open or closed-top bodies are tlle mo t suitable for the transport of dllctwork Careful consideration should be given to the
Adequate floor space IDust be provided within tbe building for the site storage of ductvork Such storage shalt make due allowance for thc stOf(ne of ductwork in stacks such that access ~ egt
between them is of sufficient width to pennil the removal of item without interference to
unloading of transport on sit a not all siJes b n fit from the material handlino- and access facilities that exi [ in a manufacturing workshop such as crane- fork-lifts or loading bay Site handJiog facilities along with
adjoining sta ks Ductvork components should be positioned so a to avoid crushing Ductwork of small panel size may be stored horizontally however care should be exercised to ensure that tack sizes are limited 10 within
ehicular acce s restrictions may itilluence the type and ize of transport to be uWised
engtlls of ductwork should be positioned 0
the tmctural strength of the duct sections to prevent distortion of the lower sections within the stack
as to avoid crushing Lengths Witll projections such as branches and bends i1anges girths damper quadrauL should be loaded so as to
54
DW154 S1tciic(ltioll for Plastics Ductwork
85 Internal cleanliness of new ductwork The site storage of ductwork introduces the important cODsideration of maintaining the internal cleanliness of the ductwork R feren e should be made to HVCA documentshybull DWffM2 Guide to Good Practice - internal
Cleanliness of New Ductwork Installations If the above conditioDs can not be satisfied consideration should be given by tJle designer to amending the specification to include for Po t Installation Cleaning as covered by tJ1C HVCA documentshybull TRJ17 Guide to Good Practic - Cleanliness
of Ventilation Systems
APPE DIXC
Fi e Retardant inishes C1 Improvement in the fire retardancy of plastic
ducts can be achieved to varying degrees and is wholly dependent llPOll the surface coating laminating resin selected and construction specification adopted In some instances smoke emission is coILSidered equaUy with other speci fication requirernen ts of the materials resistance to ignition and bumjng It is therefore important for design rs to establ ish the clients and officers detailed requirements and not rely on a tbird party interpretation of fire resisting or fire retardant Where possible the specification should refer dir etly to compliance with a British or European Standard identifying the specific sections applicable There are various types of resin and mat rcLnforcements that can achieve a Class 1 surface spread of flame ratin o when tested according to BS476 Part 7 (1987) This test puts materials illto Class I - 4 in descending order of perfoDllance according to the rat and extent of flame spread over their surfac under standard beating conditions Materials should also be tested for flre propagarion to BS476 Part 6 (1989) Tbi tesr measures the amount and rate of heat evolved by the material when subjected to standard heating
conditions Test results are given as an index of Perfonnance (i) whicb is based on three sub indices (iJ (i1) (h) The higher the value of the Index of Performance (i) the greater is the material s contribution to fire growth The higher the value of the sub-index 0) rhe greater the ease of ignition aod flame spread The highest product performance classification as defined in Approved Document B of the Building Regulations is Class O This is acLlieved if a material surface of a composite ploduct i~ either a) composed throughout of materials of
limited combustibility or b) a Class I material which has a tlre
propagation index (i) of not more than 12 and sub-index (i l ) of nor more than 6
01 J Class 0 is not a cla$sif1cation identified in any British Standard test
There are resin system reported to be classified to Class O when tested to BS476 Pcl1S 6 and 7 however designers need to ensure that such sysrems can be applied to their proposed design In propriety resinmat system available the fabrication techniques and COITect application are critical to the integrity of the reinforcing and clas ificatiol1 For example in some systems the u e of a non-fire retardant gelcont on a fire retardant substrate would reduce the classification For further information see HVCA publication DW144 Appendix D
55
DW154 SplCijiClIliol1 for Plastics Ductwork
x Guidance otes For nspectmiddoton Servicing a d
Clean-ng Access Openings
D1 GE ERAL This appendix highlight in ummary fOI111
the acce considerations that hould be made by the design r iD terms of inspection servicing and cleaning Having considered the seop and the design of the dUCI work system relative to the guidelines outlined below the designer should clearly indicate which levels of acces should be incorporated into the manufacture of a new duct work system (See Table 14 and Note I b low it
D2 DESIGN CONSIDERATIONS
D21 In ptction and servicing requireshyments are set out in Section 15 of Lhis specification
D22 Cleaning requirements are set out in the HVCA pubUcation TRl7 Guide to Good Practice Clean Lines of Ventilation Systems and the guide tates The precise location ize and
type of access would be dependent on the type of ductwork cleaning inspection and te ting metbods to b adopted Care protection and standards of cleanliness prior LO cOlllmisionin o
are set out in th AV A publication DWITM2 Guide to Good Practice Internal Cleanliness of New Ductwork Installations and th guide state Wh re specific limits of cleanliness are required ductwork sball be cleaned after installation by a spcialist cleaning contractor It will b in the interests of tht desioner botb financially and practically to cunsider employing a specialist c1eauing contractor at tbe
outset of a contract to internally clean newly installed ductwork prior to bandover This approach would reali e the following benefit shyi) Tb actual numb r of cleaning
access panels could be detennined to suit the method of cleaning to be adopted (This may be 1 s than the maximum requiremen listed under Lev 13 of Table 14)
ii) Clear directions could b given to the ductwork contractor as to tJle size and location of cleaning access panels that are required to be fitted during the mauushyfaclunng pro s
iii) The specialist cleaning operation prior to commi ioning vould enable the cleaning contractor to verify the practical acee requirement for the future cleaning operation associated -vitb a regular maintenance programme
iv) A specialist cleaning operation prior to commissioning would allow the designer to omit from the speeilicatiolJ the DWrrM2 requirem nt for factory sealing protection wipe downs and capping-off
v) Specialist Ieall ill 0 to the measurable standard defin d in TR17 will allow an objective definition of cleanline to be achieved
Car ful consideration must be gIven by the designer to the practl aJ problems associated witb the manufacture and fitting of suitably si Led access panel on small cross section duct and on the circular faces of rouod and flat oval ducts in particular
D23 Special con ideration must be given by the de igner to the practical problems associated with gaining personnel access to heavily congested ceiling areas and multi-la red du twork systems This approach would avoid
56
DW154 Spfciication for Plastics Ductwork
the possibility of access panels being D3 ACCESS 0 IN-LINE EQUIPMENT incorporated into a ductwork system at the This appendix unly covers acc il1spection manufacturing stage that were later found in through the ductwork body adjacent to an item practice to be inaccessible for either ervicing of in-line equipment and not openings in the or cleaning activities equipment itself
able 14 Acce requirements for inspection servicing and cleaning
HVCA PUBLICATIO REFE NeE (uidtgt 10 Gund Prartict
Adjace t OW144 Cleanliness orVcnlillltio S~lcr~ fRjJ7
in-line LeyeJ 1 Level 2 Level 3 ite sequipment pcdionSen lcin~ Section d C1eaniJl( SUn(O)lnspc lion Palle ltk~m_n
2011 (minimum OiL Jubje-ct to duct ~zel (ft~ -Panels
Control Da pcrs One (inspection) 203 One 300 mm x 200 mm Both sid Fire Dampers One (sCTjdJl~) 20211 One 300 0101 x 200 mm One side HeatingCooling Coils One (inspedion) 20213 One 300 mm x 200 mm (lIpstream) Both sides Attenuators (rectangular) None required One 300 mm x 200 mm (downstream) Both sides Attenuators (circular) one retluired One 300 mm x 200 mm (downstream) One side Filter Sections One (inspection) 20212 one required Uoth sides Air Turn Vanes None requjred None required Both sides Changes of Direction None required one required One side In-Duct FansDevices One (inspection) 20213 None required Both sides l
1 In the absence of any indication by the designer only Level ) access will be jncorporated into a new ductwork system
2 Tbe panel izes associated with Lev lis I and 3 acee s ar e middottablished by reference to Section 20 of DW144 and Section 2 ofTRll7 respectively
57
DW154 Speclfifatio for Plastics Ductwork
pA XE
B-bliography Included in this Bibliography are technical pUblications which may be of interest (0 ductwork designers fabricators and erectors and to tho e in the heating ventilatlng air conditioning industries generally nquiric should be made of the relevant organisation at the address quoted Since its publication other addresse contained within 0V154 mav have changed and some pubJicalions may have been superseded
HEATING AND VENTILATING CONTRACTORS ASSOCIATION
4 Palace Court London W2 4JG Telephone 020-7229 2488 Fax 020-7727 9268
Orders fo FlY A Publications Old Matlsion House Eamont Bridge Penrith Cumbria CA 10 2BX (Telephone 01768 864771 Fax 01768 86718) Email hvcapoblicationshvwelfarecouk DWn 44 pe ilicatiun for sheet mctal duclwork (Iow- mediulllshy
and high-pressure) 1998) DWIl4 A practical guide to dUGI ork I akage te ting
(revised 2000) DWII54 Specification for plastic~ duct rk DW171 Guide to good Practice for kitchen venlibtion system DW191 Guide to good pracuce glass fibre ductwoJk DwrrMI Acceptance cheme for new products - Redangolar cro
joint classification Guide to good pra tice - Internal cleanliness of new ductwork installations Guide to good practice for the design for the Installation of lire and smoke uampers
J 1Other puhlications
HampV safely guide 5th edition JS2 Tool box talks JS5 Weldlng Safety booklet JSI9 afety facts bo klet Fact sheets 1-24 2nd edition JS2J COSHH manual volume 1 Advice on compliance with the
regulations 1521A CO I-rH manual volume 2 Asses mcnt h ets JS23 Ri k management manual TR3 BrazinltT and bronze welding of copper pipework cUld sheet
(I 976) TR5 Welding of carbon steel pipework (1980)
TR6 Guide to Good Practice for Site Pre sure Testing of Pipework (19 0) Guide to good practice cleanliness of ventilation Ylem
CHARTERED IN TITUTlO OF BUILDING SERVICES E G EERS Delta House 222 Balham High Road London SW12 9BS rTelephone 020-8675 5211 Fax 020-8675 5449) CIBSE Guide Volume A Design Data Volume B In tallatiol1 and quipment Data Volume C Reference Data
CommlssioniJIg Codes These Codes eover the preliminary checkS eUing to work and regulation of vanous catcgories 0 plan The Codes give a guide to design implications Series A Air Distnbution Systems Series B Boiler Plant
ri s C Automatic Conlrol ystems Cr1es R Refrigerating Sy terns
Sene iN Water Distribution Systems
Technkal Memonllda TM 4 Design Notes for the Middle East TM bull Design otes for Ductwork TM 13 Minimi iog lhc Risk of egiounaires Disease
Research Reports RROI95 Ventilation system hygiene - A review of published
infomlatioo on lhe occurrence and ffects of Olltamination Rl~02J95 Air-to-air heal rec v ry RR0395 rnfluen e of HV C on smoke detectors
ATlONAL ENI [ERING SPECIFICATION LfMITED Southgatc hamber 3739 Southgate Street Winchester S023 9EH (Telephone 01962 842058 Fax 01962 R(8982) BUfLDING S RVICES RESEARCH AND [ ORMATION ASSOCIATIO Old Bracknell Lane West Bracknell Berkshire RG 12 4AH (Telephone Brackl1eU (01344) 426511 Fax 01344 487 -7 )
Application Guides AGln4 De tglJing Vana~le Volume middotylans for KOOnl
iir Movement AG1I91 Commissioning of V Sylcms in Buildings 11 6194 Fire Dampers
B) 94 cntiJalion or KitcneTls
AG389 The Commls ionin of Air Systems In Buildmgs AH2192 Commissioning of Bern - A ~ode of Practice TN2417 I Fire Dampec il) Ventilating Ducl
BEATING VENTILATING A AIR CONDITION G MA UFACTURERS ASSOCIATIO (HEVAC) HEVAC Henley Road Medmenham Marlow Buck SU 2ER (Telephone 01491 578674 ox 01491 575024 Emoimiddot infofetacouk)
Publicatjons Air Diffusion Guide Guide to Air Handling Unit Leakage Testing Guide to Good Practice Air Handling Unit Real Room Acoustic ~ st Procedure Specification for the ertiiicatioll ofAir Filters Method of Test for Water Rejection PerfOnTlatce of Louvrcs Subjected 1(1
Simulated Rainfall Test Procedure for Acoustic Loo cs Specification 10 Floor GrilJes - Types Performan e and Method ofTest Specification for the Determination of the Collection Efficiency of SilJ1d
Trap Louvre Domestic Mechwlical Vclltllalion Systems with Heal Recovery Fan Application Guid
~an and Ouctwork Installation Guide Guide to Fan Noise and Vibration
pecification of Requirements for JallJral Smoke and Heal Exhausl Ventilators
pecification for Powered Smoke and Heat Exhaust Ventilators
Specification of Requirements for Smoke Curtains Design Gujue of Smoke Ventilation for Single Storey Lodustrilll Building~
Including those with Mezzanine Floor and IIi Racked Storage Warehou es - Issue 3
Guidance for the Design of Smoke entilation YSlem for Covered and Undergrollnd Car Parks - lssue 1
Application of SOloke Control Equipment and Syst m Guid to Good Practice - Isue J
58
DW154 Sp(C~tiifitiol for Plastics Ductwork
BRITISH STANDARDS INSTIT TION Sales Department 101 P ntooviLle Road London NI 9ND (felephone 020-78 1 78801)
CP 413 1973 Ducts for building ervices
SS 476 Fire tes on building matenals and lruc(ure
Part 4 19 4 Non-combustibility lest or materials
Part 6 I Fire propagation lest for materials
Part 7 1993 Surface spread of tlarnJ tesls for materia
Part 20 1987 Fir resistance of elements of construction
Part 21 1987 Fire r sistlUlce of loadbeanng elements of construction
Part 22 1987 Fhe istallceofllon-loadbearing elemcllts ofconsttuclion Part 23 1987 Contribution of componcnts to the fire resistance 0 a
structure
Part 24t987 Fire resi lance of wl1lilation ductl
SS 5588 nan 919 0 Fire Precautions III thc desIgn and OOSlnJ lion of buildings
S 729 1971 Hot dip galvanized oatiugs (or irOIl aod stcel articles
BS 1449 Steel plate sheet and Irip
Pan 11991 Carbon steel plate heel and strip Part 2 1983 Stainless steel plate sheer and strip
and
B middotENJOI49-2 996 BSEN 10149- 1991)
BSEN 10131 1992
BSEN22063 Sprayed metal coarings 1994 Protection of iron and steel by aluminium and zinc against
atmospheric cOlosion Irotectiotl of iron and ste I against corro ion and oxishydation at elevared temperatures
BS 353 1981 Glossary of lerms relnting to thermal insulation
BS ISO 1479 Self-tapplngscrewsandmetallicdri c crew
B -lSO 7049
1994
B 4800 1989 Painl colour for building purposes B 4848 l0 rolled structural steel sections
Part4 1972 Equal and unequal angles BS 5422 1990 Specification for the use of therm illuating matcriulS
SS 5720 1979 ode of practice for mechanical veutilating and air C 11shy
dirionin bull in building
l3S PR 12814-1 Bend resting for plasric welds
SS PR 12814-2 Tensile testing for plastic welds
SS PR 13067 Appro altesting for plastic welds
BS PR EN I 100-] Vi ual in pection ofplaslic welds
SHEET METAL AND AIR CONDITIONING CONTR-CTORS NATIONAL ASSOCIATION INC (SMACNA) Headquarters 420 I Lafayeue Center Drive Chanlilly Virginia 2051-1209
Mailing Address pa Box 221230 Cbantilly Virginilt120 153-1230
Telephone (703) 803-2980 Fax (703) 803-3732
Accepted IJJdustry Pl3Gtice for Industrial Duct Constnlelion 197 ) i-rchitecmral Sheet kwl Manual ([993)
Comractors Guide lor Modification 10 ooslruerion Colllraets 1993 Ducted Eleclric Heat Guide for ir Handling Ssrerns (1994)
En~rgy ollservatioD Guidelines (1984) Energy Recovery Equipment yslClllS (199l
Fibrou GIns Duct onS1ntClion Standards (1992)
Fire Smoke amp Radiation Damper In tall Guide for HVA Syst ms (1992) Guide t leel Stack 1(95)
HVA Air Duct Leakage Test Manual (19 ) HVA COlllmissioning lvlanual (1994)
H A Duct Construction Standards-Metal amp Flexible (1995) Addendum 01 (Nov 1997)
HVA Duct Systems Inspection Guide (1989)
HVA ySlems-Application (1986) nVAC ByternS-DLlct D ign (1990)
HVi Systems-Testing Adjusting amp Balancing (1993)
indoor Air Quality Manual (1993) tcheu quipment Fabrication Guidelmes (1990)
Managers Guide for elding (1993)
Rectangular Industrial Duct Cons1TUction Standards (19 0) Round Industrial Duct oustmction Standards (1977)
Sei mic Restraint Manual (1991) (wl Appendix E 1993) SMACNA Ma le Index ()fTechnical Publications (1995) Tbennoplnstic Duct CPY ) Construction Manual 1994)
DEPARTME OF THE ENVIRO MENT (Publications Centre) H Stationery Oflice 5 Nine Elms Lane London SWS 5DR
MampEJ 011972 Electrical in tallat1011 in buildings ( ew Editiou)
IampE 0319 Healing hot and cold wat r steam and gas losla1lations for buildings
M amp - No4 1970 Central heating and hot and cold ~ ateT in tallations for
dwelling
M amp ENo100 1971 Mechanical ventilation for building~
ASSOCIATION FOR SPECIALIST FIRE PROTECTlO As ociation House 235 Ash Road AJdershot Hampshire GUl2 4DD
Telephone OJ25221322 Fax 0 J252 333901
lublicalioos Fire Ratcd and moke Outlet Ducrwork An Industry Guide t Design and InSlalla lioll
HEALTH AND SAFETY EXEC TIVE Rose Court 2 Southwark Bridge London SEl 9HS Telephone 020-7717 6000
TWJ THE WELD G TlTUTE Abington Hall Abington Cambridge CB16AL Telepbone 0 J223 89162
Publication DatJ Oil w~ldll1g of lhermopla lics
59
DW154 wciiwlioll for Plastics Ductwork
A -=--DIX
Factors
Specific gravity shy pp = 091 approx UPVC = 14 approx
Some miscellaneous conversion factors
To convert
Length Inches to millimetres Feet to metres
Multiply by
2540 03048
To convert
Millimetres to inches Metres to feet
vIultiply by
003937 3281
Area Square inches to square millimetres 6452 Square millimetres to square inches 000155 Square feet to square metres 00929 Square metres to square feet 10764
Volume Cubic feet to cubic metres Cubic feet to litres Gallons (UK) to litres
002832 2831 4546
Cubic metres to cubic feet Litres to cubic feet Litres to gallons (UK)
35315 00353
022
Mass Ounces to grams Pounds to kiJograms Tons to tonnes
2835 04536
1016
Grams to ounces Kilograms to pounds Tonnes to tons
003527 2205
09842
Volume flow Cubic feet per minute to cubic Cubic metres per second to cubic
metres per second 0000472 feet per minute 2119 Cubic feet per mIDute to litres Litres per second to cubic feet
per second 04719 per minute 2119
Motion Feet per minute to metres per second 000508 Metres per second to feet per minute 197
Pressure Inches water gauge to millibars 2491 Inches wateJ- gauge to pascals (Pa) 2491 I Pa = I ewton per square metre = 10-2 millibars
60
Heating and Ventilating Contractors Association Esca House 34 Palace Court London W2 4JG
Tel 020 7313 4900
e-mail contact Itvcaorguk web site wwwhvcaorguk
Fax 020 7727 9268
DW154 SpedflCiltion for Plastics Ductwork
Cross joint - recta gular ducts
Fig 1 Socket and spigot joint (UPVC and PP)
Conlinuou weld joint on sile onlinuou- wcld
CT~r~T2
Fig 3 Flange joint (UPVC and PP)
ontinuou weld
Fig 2 Socket and spigot joint (UPVC only)
Fig 4 Flange joint (UPVC and PP)
S iffeners - rectangular ducts
Fig 5 Flat Fig6 Angle
Oatim wo]
Fig8 Bends - examples of hardTie rod assembly and easy
Hard
Fig7 With spacers Easy
4
DW154 Speci(uariml for Plastics Ductwork
Fig 9 Turning Vanes
HOWl G TYl AL EXAMPLE OF FOCI G
15
Ma vane length shy 615 mm
Example ofbraemg when V1IIle length exeeed max pennined Ahematively two banks of ncs fixmg the centre rail together at ] 50 mm nrrcs
U~_II---- fixed to dnct wall both CDds
bLEVATION
vane
Maximum distance between centrc oflUming vanes should [Jot exceed 60 mm pitch
DW154 SPCCijicllfiull for Plastics Ductwork
practice to provide common terms ofPA T4 reference for designers quantiry urveyor and
Circular Ducts
12 CIRCULAR DUCT SIZES Th duct sizes [n Table 4 have been selected from the ISO and C standard ranges as the 132 preferreod sizes
Table 4 Circular ducts shystandard extruded tube sizes
133 Extruded tube
ISO Standard Sizes (Nominal Diameter) 11
Wan Wall Thickness Thickness
mm mm mm mm 110 500 4022
I25160 600 50 I25200 630 60
225 25 700 60 13425250 800 63
280 900 70 315
23 23 80
355 1000
25 1250 104 400 32 1400 108 450 35
Note The above sizes are subject to normal manufactl1ring tolerances Other size may be available in varying wall Lhicknesses and subject to test and operational pressure
13 CONSTRue ION
13 General Tllis specification covers duct sizes up to a maximum diameter of 1500 mm The minimum constructional requirements for UPVC amp PPPPS un-reinforced ducts sball be as Tables 6 amp 7
ductwork contractors and tho e using computers in ductwork design and fabrication The requirements for circular duct fittings apply throughout the size ranges covered in this specification
Sheet jointing seams Seams shall be joined either by continuous fLiJer rod hot air welding or by fu ion welding Other forms of jointing are not acceptable
Socket and Sl)igot joints Socket and spigot joints shall be formed by purpose made double socket pieces 100 mm long and of the same thickness material as tJJe duct welded into position on each tandard length of duct forming 50 mm deep sockets prepared and ready for final jointing on ite with PVC adhesive andor fill r rod of the same formulation used for fabrication
Flanged joints
1341 Flanges abricated flanges shall be conshy
structed using minimum of 9 mm thick by 50 mm wide material of matching formulation depending on duct size as shown in Tables 6 amp 7 The flange shall be mounted true and square to the duct surfaces and welded OD both sides a 103 and Fig 12
1342 Drilliogs Drilling ball be placed to permit clearance to the external casing and any reinforcement of the ductwork
1343 Fastenings For normal application bright zinc plated bolts nuts and washers hall
16
For srualler diameters preformed fittings are available otberwise fitting are fabricated from segments of duct or sheet welded together
The terminology and description of circular duct tiltings as set Ollt in Section 25 are recommended for adoption as standard
be used in sizes and pitCh centres shown in Table S Wh re special conditions prevail consideration of other material finishes such as stain le steel bolt nuts and wasbers shall be u ed In all ca cs gasket materials as Seciion 825 shall be USed
DW154 Speciliwriml for Plastics Ductwork
135 Stiffeners
1351 External stiffeners Shall be fitted as specified in Tables 67amp 1 I and Fig 13
1352 Internal stiffeners The use of internal stiffening or bracing hall be acceptable if deemed neces ary and appn ved by the designer
f 36 Expansion joints Where the corrfiguration of the ductwork does not provide for movement due to temperature
Cross joints - circular ducts
change or where such movement is restricted by branches or attachments expansion joints should be fitted (See Section 18 Flexible Expansion joint connections)
It is the responsibiLity of the designer to identify the position of any necessary expansion joints based upon design parameters for the individual systems (See Figs 23 24 2534 amp 35)
Design Note Examples of expansion joints shown are not suitable for movement exceeding 30 mm
Fig 10 Socket and spigot joint (UPVC and PP)
ConLinuous weld joim on ite Ontinuous weld
crlr~l
Fig 12 Flange joint (UPVC and PP)
Continllous wcld
boil
Continuous weld or Solvelll cement
Solvelll ccmcnl joim on sile
Fig 11 Socket and spigot joint (UPVC only)
Stiffeners - circular ducts Table 5 Fastening centres shycircular duct flange jointsFig13 Flat
flat conljnlJou~ly welded Diameter Pitch Bolt Size
max
1 2 J 11
1 shy -~
mm mm mm Up to 600 100 8 with washers
601middot1000 100 10 with washers - ---I
1001middot1500 100 10 with oversized washers
1
Minimum offourfixings
17
DW154 Specifiiutiofl for Plastics Ductwork
Table 6 constructional quiremen s - circular unshy inforced U VC
Diameter Minimum Joints Stiffeners Maximum spa ~in r
Sheet between Thickness Jointsl tiffcners
1000 Pa 1500 Pa
1 2 3 4 5 6 UD mm mm mm mm
UO to 600 3 socket amp spigot as Figs 10 11
or fla ged Fig 12
601 to 1000 45 socket amp spigot 50 x 9 flat 2400 2400 as Figs 10 11 welded bo sides
or Oanged as Fig 13 as Fig 12
1001 to 1500 6 Hanged 75 x 9 flat 1200 1200 as Fig 2 welded both ides
as Fig 13
Applies 10 Tables 6 alld 7
Note 1 For constructional operating temperature limit refer to Part 2 luu 54 2 To allow for conicleration or extruded se lions or fabricated component the materia] tllicknes i hawn a nominal
Table 7 Minimu onstrucfional requirements shy circular un-reinforced PPS and
Diameter Minimum Joints Stiffcners Maximum pacio Sheet between
Thickness Join sStiffener 1000 Pa 150n Pa
I 2 3 4 6 mm m m mm
110 to 500 3 socket amp spigot as Fig 10 or flaoged as Fig 12
501 to 750 45 ocket amp spi~ot
as Fi 10 or Uanged as Fig 12
751 to 1000 6 tlanged 50 x 9 Oat UOO 12 0 as Fig 12 welded nth sides
as Fig 13 1 1 to 1250 6 flanged 75 x 9 flat 800shy 800
as Fig 12 welded both sides as Fig 13
1251to~ flangcd 75 x 9 Oat 600 600 as Fig 12 welded both sides
as Fig 13
18
DW154 Sped(icalirm for Plastics Ductwork
PARTS
Hangers an Suppo ts
14 GENERA
141 Supports are an e sentiaJ part of me ductwork system and their supply and in tallation are normally the responsibility of the ductwork contractor The principl s are a I-rvCA publication DWIl44 Part 6 Section 19 and should be read in conjunction with this document
Design Note Designers may pecify specific requirements wbich will supersede guidance given in DW144
142 Rectangular ducts abl 8 give the- minimum requirements for
hanger and supports for un-reinforced ductwork
143 Circular ducts Table 9 gives the minimum requirements for hangers and upports for uD-reinforced ductwork
144 Vertical d cts The design of supports for vertical duct is dictated by site condition and where practical duc hould be upported at 4000 mm interval or where tbey pa s through a floor (but n ver exceeding 4500 mm) see Figs 17 amp J8
145 External ducts Where ducts are external to buildings and may be ubject to wind loading support should be plac d so as to restrain ide tl1ruSt and should allow axial movement as neces ary It is the respon ibility of me de igner to calculate the effect of the particular prevailing condition and to define any special upport requirement
146 Expansion joints Support shall be designed to permit axial movement only and shall e provided on eitl1er ide of expansion joint
I 1shy
I~
mm -Jp to 400
401 to 600 601 to 1000
Table B Hangers and Supports - rectangular horizontal ducts
Hanger Bearer Drop Roll Formed Rod
Long r Side
Cbannel ~-shy ~
---shy
Maximum ~pacing
4 52 3 _ -c Fig 15 - Figs 14 15 16 amp 2J
shy
mmm mmmm 240025 x 25 x 16 40 x 20 x 15 8 240040x20x15 40x 20 x 15 10 240040 x 20 x 1~510 40 x 20 x 15
shy
I
40 x 40 x 15 40 x 40 x 15 24001001 to 1500 I 10
Table 9 Hangers and Supports - circular horizontal ducts
Longer Side Hanoer Split Clips Maximum spacing Drop Roll f-ormed and Wrap-round Rod ~hannel Hang r
2 3 4I Fig 1920 amp 22Fig I
mm mmmm mm mm 25 x 25 x 15 IIp to 355 8 40 x 3- --1-_ 2400
2400
2400 2400
70x 6
40 x 5 SOx 5
40 x 20 x 15 40 x 20 x 15 40 x 40 15
10 10 10
356 to 600 601 to 1000 1001 to 1500
19
DW154 Spccijicutioll for Plastics Ductwork
147 Protection specification Any special coatingpaint Unless otherwise stated all support shall be finishes for protection against hostile manufactured in material as specified in this environments shall be advised by the designer
SUPPORT BEARERS
~ 14 Flg16 Inverted profile
angle I ~lIed steel
channel (alternatives) Fig 15 Profile channel (alternatives)
TYPICmiddotAL VERTICAL DUCT SUPPORTS Flat bar clipStiffening frame Outline ofinsulation stiffening frame or tlanged joint (if applicable) or flanged joint
Stiffening framc or flanged Joint
~~-I ( ee notes 10) I
r--~ -++- ~--4==J===4~---
Fig 17 Vertical rectangular ducts Fig18 Vertical circular ducts
The support bearer which depending on ducti tructural opening size could be either channel or angle section may be ll1ilised in any of the following arrangementsshy
a) To support the underside of a flat bar clip in halves (circular)
b) To support the underidc of either the stiffening frame oftbe flanged joint ofaoy duct section
c) To support either a stiffening frame Or a flanged joint below nsing drop rod srudding
20
DW154 Spediraiml for Plastics Ductwork
Arrangement of bearers and hangers (to be read in conjunction with Table 8 amp 9
wbich list material sizes relative 10 duel izes)
KEY Limits refer to actual duct size - insulation is additional - Typical
attachmentv -Atta hment t strucUlrcI to strucUlrc
I I
I - Flat Bar
I - Drop rod or - utlinc of lllddmg In ulillwn (if
applicable)
Alternative 7 drop rod or rt------------ 1 studdmg q I
I I Rectangular
ii i n 1
Fig 21 Rolled or profiled bearer Limit oncFig 19 Wrap-round hanger Limit 55 DIA
V v Drop rod orAllernaUC 1 1 tudding
drop rod or 1
-- -- 1studding and elded bas 1
I I0 -_
Limit 355 DIA Frg 22 Split clips Limit 1500 DIAFig 20 Flat strap hanger amp split clips
21
DW154 Specification for Plastics Ductwork
6PA deElned in J62 appropriate to the airflow pressure acoustic temperature and corrosion
General
15 ACCESSl SPECTION OPENINGS
151 General These are for inspectionservici ng on 1y
HVCA publication DWIl44 Part 7 - General Section 20 sets out the requirements for access applicable to this specification
152 Cleaningmaintenance Designers shall take specialist advice and then stipulate their requirements for the periodic internal cleaningmaintenance of ductwork and of the consequent need for adequate access for specialist cleaning equipment including the size type and locationfrequency of the actual access openings required
Appendix D sets out guidance notes for the consideration of cleaning access and also makes reference to the HVCA publication TR 17 Guide to Good Practice Cleanliness of Ventilation Systems which covers the su~ject
in greater detail
Note A majority of in tallations in which plastic ductwork is used are considered to have a nigb operational risk potential and provision of access should address this
16 REGULATI G DAMPERS
161 General Balancing dampers and control dampers are elements inserted into an air di tribution system or element of an air distribution sy middottem Balancng dampers permit modification of the air resistance of tbe system and consequently cbanging of the airflow rate Control dampers control tlle airflow rate and may in addition provide low leakage closure of the airflow
The deigner shall specify damper locations taking into consideration that good design practice requires a minimum of five times the diameter or width of the shortest side of uninterrupted flow between plant connections and the damper and select the damper type as
characteristics
1611 Balancing damper To achieve the required distribution of air in the ductwork system at inlets andor outlets for [hi purpose the damper blades are set and Jocked manually in position between fully open and fully closed
1612 Control damper To secure dynamic control of the air now in the ductwork system In thi function the damper will always be power actuated and may require to be modulated between fully open and fully closed and to be capable of taking up any position between these extremes In the fully open position the damper should have a minimum pressure drop In the fully closed position it will not necessarily achieve a complete shut off
162 Types of airflow control dampers Airflow dampers of various types are available for specific purposes as follows
1621 Single - blade dampers Single-blade dampers shall consist of a si ngle pi voted blade cOlllained withjn a casing or section of ductwork The blade shall be adjustable tbmugh a nominal 90 angle by means of a quadrant or similar operating mechanism Where automatic control of the damper is required the spindle shall be extended to enable a powered actllator to be mounted
Single-blade dampers shall have a maximum duct width of 400 nUll and a maximum duct height of 400 mm for rectangular ducts and for circular ducts a maximum diameter of 400 mm
1622 Multi-blade dampers Multi-blade dampers shall consist of a number of pivoted blades contained within a casing The blades shall be
22
DW154 Sedicalirm for Plastics Ductwork
adju table through a nominal 90deg angle simultaneously by intershyconnected linkage or gears connected to a quadrant or similar operating mecbanism Where automatic control of a damper is required a spindle shall be extended to enable a powered achlator to be mounted
There is no restriction on the size of duct in which multi-blade dampers or damper assemblie may be u ed Where dampers are required for blade lengths in excess of 750 mm the blades should be suitably reinforced or supponed 0
individual damper blade should exceed 200 mm in width
1623 Iris dampers Lris dampers shall consist of a nUlllber of radialty interconnected blades which open or close within a casing with duct COlll1cctions The blade shall be simultaneously adjusted by a quadrant or similar operating mechanism
Iris dampers shall be installed as specified by the manufacturers operating and installation instructions where the product is unidirectional with regard to airflow
lris dampers are available for circular ducts only in diameters up to 250 mm (it should be noted that the damper casin i appro)(imately twice the diameter of the duct)
1624 Backdraught dampers Air pressure operated uni-directional rectangular (single or multi-blade) with adapters if fitted to circular ducts
1625 Slide and blast gate dampers A damper [lsed as a shut off facility with an externaJ Lide bousing allowing the blade configuration to be fuJly inserted to fully extended for maxiDlUlll air flow
163 Construction
1631 Materials All products shall be protected against cOHosion as necessary and supplied in a fully finished condition as specified by the designer
1632 Dampers used in low and medium pressure systems The following recommendations apply to dampers forming an integral part of ducrwork with pressure classifications A and B air leakage limits
The dampers shaH be constructed to minimise distortion and prevent jammin in operation Th blade shall be sufficiently rigid to minimise movement when in the locked pOSitiOLl
The blades shall be securely fixed to the operating mechanism All balancing dampers shall have a locking device located on the outsid of the case and shall giv clear indication of the actlwl blad position All penetrations of the duct shall be fitted with suitable seals where necessary
1633 Dampers used in high pressure systems Regulatino- dampers used in duc[work sy tems to pressure cJassification C shall meet tbe construction requireshyments specified in 1631 and 1632 with operating mechanisms out of the air-stream
1634 Proprietary types of damper The use of any specific type of proprietary damper shall be confirmed by the designer In all cases proprietary dampers shall meet the relevant requirements of thi specification
1635 Damper casings Duct damper casings hall be constructed to meet th mllllmum
23
DW154 SpeciJimlioll for Plastics Ductwork
leakage Iim its sp cified for th c1uctwork ystem to which tbey are installed
In order to apply the square metre leakage calculatio as detailed in DW143 A Practical Guide to Ductwork Leakage Testing the reference casing area ball be taken as the perimeter ize of lh damper IDultipli d by the equi alent length of Imetr eg an 800 mm x 400 mm duct damper hall have a surface area for casillg leakag p donnan calculated as follow (2 x 08) + (2 x 04 x I
=24m2 casing area
Other pelforlllance ancl rating test methods for damp f and valves are specified in ISO 5129 and BSIE 1751 and are referenced belm a) Leakage past a closed damper
alve BSIE 1751 b) low ratepre sure requirement
characteri t cs BSIE 1751 c) Operational torque le ring
BSEN 1751 cl) Thermal transfer testing
BSIEN 17 I e) Reg nerated sound power levels
ISO 5129
164 Installation Dampers shall be imaalled in accordance will) any re Ievant ISO EN or British Standard 10 aJ bUT lcling regulation and national code of practice as well as the manufacturers recommendations
17 FIRE DAMPERS AND INT MESCENT SLEEVES
171 General Damper or sleeves arc requiTed on duct y~telll where the designer has -tjpulated the
duct wiU penetrate a fire compartment in the majority of application tbermopla ti ductwork is ugtecl where contamlDated corro ive or otherwise exceptional fumes are concerned it is preferable to use tire damp r which are externalJy mounted ie of the intmnescent operated crush typ
24
72 Fit-e rating The damper assembly should have a fUT
resi tance ratin o equal to that of the fir ban-jer it penetrate and ball be fire tested and rated to the timetemperature curv of B 476 Part 20 and 22
173 Intumescent sleeve At the time of writing this specification qualified test results were available for rectangular dampers and circular dampers up to 55 mm diamet r Manufacture have indicated that they are able t provide speci fications for other size and diameters This infonnation should be confirmed b th de igner Various type are available includino
tho e incorporating ruechanical closing plate and those operated anI by expanded iJllUme c nt media
In all ca es fire damp rs and intnmeBcen leeves shall be supplied and in taUed in
accordance with the manufacturer iJlStructioos and COSHH a essm nt
174 Other types Fire dampers of mious types are availabl for specific purpose~ ee HVCA publication DW144 The de igner should )lot (hat materials for con lt1Jction bould be uitablc for the par1icular application
ALL C SES FIRE DAMPERS AND fNT MESCENT SL _VES SHALL HE S PPLTED AND INSTALLED IN A ORDA CE WITH Tf--IE MANUshyPACTURERS STRUCTTONS AND COSHH ASSESSMENT
18 FLEXIBLEEXPANSION dOINT CONNECTIONS
181 General ploperties Tbe material u ed for flexibleexpan ion iojnt~
mu t meet the design r requirements for temperature air pressllrelfe resistance applicable to pl astic duct sy tem vibration and noi e br akout when incorporated into a jointconnection and shall comply ith lh standard of air-tigbtne specifi cl for the duct work sy tem of which it fOlms part (See Figs 23 24 5 26 27 amp 28 for typical con truclion clelai Is
DW154 SJecilimtol for Plastics Ductwork
Expansion joints
Fig23 Moulded bellows type (rectangular and circular)
Fig24
~F aiblc sleeve
__ liding sleeve
~~~~
Sleeve type (circufar)
Fig 25
AIRFLO
COnlinuou~
weld~
Flexible Iceve
PV A HOWN pp SE BACKING FLATS AS FIG 2
Sliding lee c Co1linuou
weld
Flanged sleeve (rectangular and circular)
25
DW154 Specificatiol for Plastics Ductwork
Flexible con ections
Fig 26 Flexible sleeve with clips (UPVC and PP)
--__ Flexible I eve
I
I
I CODn clioD to plant ~
Band clip
Fig27 Welded flexible sleeve (UPVC only)
Plastic)sed PVC slceve ~-- onll11uo1sly welded
onrreclion to planl ~
Fig28 Flanged flexible connection (UPVC and P )
t sp dally moulded flexible flanged connCClitlll
boil
C)nneclion to plant ~
26
DW154 Specificotiol for Plastics Ductwork
182 LOClt1tion Flexible joint are typicltllly lIsed at building expansion joint and fan inletsoutlets Any others required should be indicated on the de ign drawings Care should be taken to maintain alignment across jointsconnections
183 Length Flexible Jomts shall be kept as short as pra middottieable above a minimum eft ctive length of SO mm In no ca e shall a flexible joint exceed 250 mm in lengtb
184 Connections to rectang a ducts With flanged rectangular connections Ule tlexible material shall be held in pLace with flat pIa tic strip of not less U1an 6 mm thick ltlttached to the flanges using uitabJe fixings The more heavy weight type of fleAible mateLial may also be obtained formed into a channel ection with corners fitted to give a neat air tight j int For pigot connections the Be ible material shall b held in place with flat pIa tic trips n t less than 6 mm thick
t 85 Connections to circular ducts With tlanged circular connections the flexibl material shall be held in place with flat plastic backing strips or proprietary clip bands with screw or toggle fast ners
186 Welded flexible connections (Rectangular and Circular) Where the parent and llexibl material are from imilar ba ed products they can be joined to the duct u ing the welding method described in Section 823
19 PROTECT VE FINISHES
191 nles otherwise stated all ductwork shall be mallllfactured in mat fial as pecified in tbis specification Any special coatingpaint fmishes to be provid d by the duct work contractor sball be advisd by th de igner
20 CONNECTIONS TO BUILDING OPENINGS
201 Fanning and finishing building op nings are not the repoJlsibjlity of the duftw( rk contractor and the note that follow are for guidance purpo e only
2011 Openings in brick block or concrete walls shall have inset frames to provide a suitable means of fixing grille louver masking flanges or the tlanged ends of ductwork The illset frames shall be conslnlcted to maintain the structural int grity of the wlll and where applicable cavities shall be suitably lined
2012 Openin s in dry linino partItIons shall have inset frames a 2011
2013 Openjngs in cladding walls and roofs shall have flaoged leevesframes to provide a suitable means of fixing a 2011
2014 Horizontal and vertical opening xposed to oLltside atmo phere hall
be provided with a suitable weathering fini h at the external face especially where profiled cladding is used
2015 Timber framed op nings are not permitted In fj re compart ment barriers
202 Ductwork connections to building openings hall have a flange of suitable profile to permit practical fixing to the openillg frame In selecting the profile consideration shall be given to Tabl~s 2 and 10 in this specitication relating to duct ize and rating Gasket strip or sealant shall be ltlpplied between the tJaoge and building op ning frame
21 DISCHARGEEXHAUST TERMINAL
21 Tbese shall be vertical open ended and designed to meet and comply with current r gularions on contaminated flue The designer hall ensure that the de ign and perf rmance i suitable for its intended purpose Examples of some typical terminal designs are SbOiD in Figbull 102 10 bull 104 amp 105
27
DW154 SpedjimioTl for Plastics Ductwork
22 THERMAL INSULATION
221 The provision and application of thermal insulation to ductwork is not the responsibility of the ductwork contractor
222 Where ductwork is required to be preshyinsulated the specification should be agreed with tbe designer
223 Where the temperature of the air within the duct promotes condensation on the exterior surface of the duct and cause moisture penetration througb the thermal insulation vapour scaling may be required and in this case the most important requirement is to limit penetration of the seal
The extent of any vapour sealing of ductwork thermal insulation and the support method to be u ed must be clearly pecitled in advance by the designer
224 For detailed information on the thermal insulation of ductwork reference should be made to BS 5422 1990 which covers the specification for thermal insulation materials on pipes ductwork and equipment (in the temperature range -40degC to +700degC) and BS 5970 1992 which is a Code of Practic for Thermal Insulation of Pipework and Equipment (in the temperature range -lOOdegC to +870degC)
23 FIRE RETARDANT FINISHES ON PLAST C DUCTWORK
231 The designer should note tbat ductwork constructed to DW154 has no teted fire rating or information see Appendix C
24 REINFORCEMENT OF DUCTS WITH GRP LAMINATE
241 General Where ductwork is required in larg T izes than are covered by Tables 2 4 6 amp 7 or with the increased strength sometimes necessary for industrial use external reinforcement is normally pwvided by applicatioD of glass fibreresin laminate
GRP systems will bond satisfactorily with standard UPVC sheet but for pp it is
nece sary to use a specially prepared sheet with a glass fabric backing incorporated dOling manufactllfe
The detailed techniques of fabrication using GRP are outside the scope of this speci lcation but the following notes are offered for guidance of ductwork fabricators
242 Materials
2421 Quality The laminate is made up of polyester resin complying with BS 3532 and glass fibre complying with BS 3496 or BS 3749 The nominal ratio of resin to glass fibre should be 7030 by weight
2422 Minimum properties The laminate shall comply with the followiog mini mum pbysical properties
Tensile strength - 70 MNm Tensile modulus - 7 Gl m Flexural strength - 140 M Im Bond strength (hetween laminate and substrate Not less than 7MNm Bmcol hardnes Not le s than manufacturers specification
The GRP reinforcement educe the expansion of the parent material but the resultant stre ses arc well within rhe strength of the bond However the Iinear thermal expansion curve shown in Figs 34 amp 35 will serve as a guide
Surface resistivity electrkal propcltles and acoustical propertie are similar to the relevanl unreinforced materials The fire retarding properties of GRP may be improved by the use of specialisl laminating resin
2423 Forms available GRP Laminate should be built up from the separate materials ie resin aod glass fibre in the form of chopped
I strand mat or spray ravings
28
DW154 Spcification for Plastics Ductwork
2424 Workshop conditions Polyester resuls are sensItIve to lmperature and the workshop hould b maintained at a temperature of herween 20deg and 25degC HiOh relative humidities and damp onditions should be avoided A good rate of air change must be pro icled pJeferably by m chanical ventilation
2425 Storage of materials Resin and urin o agents shouJd be stored in dark cool condirions away from the working area and in confonnit with statutor requireshyments for tJle middottorage of flarmnable liquid Because of Ule Limited torage lif of the unmixed resin and curing a eot mal lials ~hould be ch eked before use to enLlfe that they are within the manufacturer pe ified sh If life (usually ix month from the dm of manufacrure)
Glass fi re should be stored separately und r clean dry conditions
243 Surface preparafon
2431 UPVC To achieve the specified bond strengtll the urface to which the GRP is applied mut first be thoroughly cleaned and then etched either by mechanical means or by the use of a suitable solvent
2432 pp with glass fabric backing To achieve the specified bond middottrength the fabric backing must be thoroughly impregnated Witll resin
244 Mixing the materials for use The re in 1 a three part mix compri lng base I sin hardener and accelerator The manufactur rs pecj[ied proportions are critical and th llUxmg sequenc pecified must be meticulously foUowed
The resin has a very limited life after mixing and before u e It is dependent on the characteri tics and bulk of th resin the alllount of hardener the degree and method of acceleration and the workshop onditions
245 Methods of application
2451 General The mixed resin may be applied by hand or b pray c1epoition The operation must b completed within the gel time of th y tern and tbe laminat fully cOI1olidated to achi v the phy ieal properties pecified
2452 Hand lay-up The duct surface i coated by hand with resin Llsing a brush and a mar of gla fibp orked in until full consolidation achieved Th proc is repeated untiJ th requird thicknes i obtained
2453 Spray depo Won The duct surface is coated WiUl re in by spray gun with the chopped glass roving added through a separate nozzle The full thickne i obtain d in layer with con olidation of each layer by hand roller
246 Construction
2461 General M ini mum COllst ructional requireshyments are pe itied ill Tabl 10 for rectangular and Table 1J for circular dUClS
2462 Joints and stiffeners Fig 29 30 31 32 amp 33 hoI TOSS
joint and tiffener for reinforced UPVC and PBPP duct
247 Worki g practices The fabrication of ductwork pecifiecl ill thi document i not affected by the addition of GRP
29
DW154 SfJcdJicatiOt for Plastics Ductwork
Table 10 Minimum constructional requirements shy
Longer Side Minimum Sheet Thicknes and
GRP Reinforcement
UPVC FBIPP 1 2 3
mm mm mm Up to 1000 3 plus 3 plus
06 kgm2 06 kgOIl GRP GRP
1001 to 2250 45 plus 3 plus 06 kgm 12 kgm
GRP GRP
2251 to 3000 45 plus 6 plus 12 kgm 12 kgm
GRP GRP
Cross Joints
UPVCFBPP 4
mm socket amp spigot
as Fig 30 or flanged as Fig 29
75 x 9 flange welded on both sides as Fig 29
75 x 9 tlange welded on both sides as Fig 29
rectangular GRP reinforced ducts
SlifTeners Maximum Spacing Between
JointsSljffeners UPVCIFBIPP UPVCFBPP
5 6 mm mm
75 x 9 flat 800 as Fig 31 or
50 x 50 x 5 plastic or MS inverted angle as Fig 32
or tormer as Fig 33
75 x 9 flat 600 as Fig 31 or
50 x 50 x 5 plastic or MS inverted angle as Fig 32
or former as Fig 33
75 x 9 flat 600+shyas Fig 31 or 50 x 50 x 5 plastic
or MS inverted angle as Fig 32
or former as Fig 33
Note 1 On rectangular duct up to 400 mm longer side no stiffeners are required 2 Applies to Tables 10 amp I I For COlJstructional operating temperature limits refer to Part 2 clause 5A 3 Tables 10 amp II apply to all pres ure classes up lo ]500 Pa
Table 11
Diameter
1 III
lJp to 1000
1001 to 1750
1751 to 2500
Minimum Sheet Thickness and
GRP Reinforcement
UPVC FBPP 2 3
mm mm 3 plus 3 plus
06 kgm 06 kgm GRP GRP
45 plus 3 plus 06 kgm2 18 kgm
GRP GRP
6 plus 6 plus 12 kglm2 18 kgm1
GRP GRP
Cross Joints
UPVCFBPP 4 III
socket amp spigot as Fig 30 or flaoged as Fig 29
75 x 9 flange welded on both sides as Fig 29
75 x 9 flange welded 00
both sides as Fi 29
inforced ducts
Maximum Spacing Between
JointsStiffeners UPVCIFBPP
6 mm 2400
800
600
Stiffencrs
UPVCFBPP 5
mm 50 x 9 flat as Fig 31
75 x 9 flat as Fig 31 or former as Fig 33 75 x 9 tlat as Fig 31 or t()rmer as Fi 33
ote On extruded tube tip to 600mm diameter no stiffenergt are required
30
DW154 Specificatioll for Plastics Ductwork
G - Cross joints and tiffeners
Fig 29 Flange Joint Fig32 Stiffener shy inverted angle
M artiPfCuQkbdd erttpObri) Wl111 RP tlddtlt
_- GRPloliu] lh~
Fig 30 Socket and spigot joint Fig33 Stiffener shy use of former
Fig 31 Stiffener Flat
I Pv FlPP ~ ~lmJaDUA1) d
OMrlQ rrnall 1( tQlS
25 STANDARD COMPONENT DRAWINGS AND ABBREVIATIONS
251 The illustrations in this section not only highlight where applicable geometric limjtations for the de ign and manufacture or ductwork components but also recommend
standard drawing representation terminology and abbreviations for both duetwork components and some of the more commonly used ancillaryplant items
252 Designers and surveyors should note that bills of quantities should provide a full description
3)
---
v
DW154 Spcc(fim(ml for Plastics Ductwork
Fig 34 Linear Thermal Expansion
u c 0 N ro 0)
b 0)
S
sect0
5 oS cl) 0)
~
on ~ ltl
c U
-30 -20 -10 0 10 20 30 40 50 60 70 80 90 TEMPRATURE C
~ V
-
~~c_ ~
~V
V ~
-7 ~
-- ~V ----
v
-6
+14
+12
+10
+8
+6
+4
+2
0
-2
--4
ig 35 Typical Design Stress tor UPVC and P
7
6
r shy 5E
-c E----0 4t) VJ 0)
ci5 0Jl 3
~
0)
Cl
2
1
o
UPVC
1
000
1
1
pp
- r-- shy r----- shy - t--shy I
__0
-30 -20 -10 0 10 20 30 40 50 60 70 80 90 TEMPERATURE C C
Note Figso 14 amp 35 shaded area refers to GRP reinforced duct
32
DW154 Speciicfltirm for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - REC ~NGULAR
Splilt~r Posilion W-mm pliucr
A B c 40]--QOO 1 W - -
601-1000 1 W4 Wf2 -
1001-1800 3 WI W3 W2
FIG DRAWING DETAfiS
tU]36 ATI Straight Duct with socket and spigol joint
rn [037 Straight Duct with flanged joints
[I []38 Straight Duct with flanged joints
rkJ Short Radius Bend
39 Applies to any augl and for duct up to 400 n11n wide
Minimum (I1m31 radills = 100 mm
Medium Radius Bend (a illustrated)
[kJ Applies to any angle
40 Long Radiu Bend Similar but radius = W
Throlll radius = W2 Applies to any angle
- Short Radius Bend with plitlers
I -shy -shy u co - t lt Li--_ 41 t 0 ~ I I I
~ I
L 1W
Minimum waal radius = 100 mm Splitters not required in bend angle less than 45deg
42 QJ1 Square Bend with turning vanes ij
3
DW154 SP(L~ficatioll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - RECTANGULAR
FIG DRAWl G DETADS
43
~
I v
L L Radius Tee with internal deflectors
44
~ Radiussed Twin Bend
45
Imiddot
er Swept Branch
46 U-
Sqoare Tee with Turning Vanes
47
~ f
Breeches Piece
48 0 y l Piece
34
DW154 Specificatioll for Plastics Ductwork
STANDARD COMPONENT RAWINGS - ECTANGULAR
55
54
51
50
53
52
49
FIG
~MX
RAWlNG
DmiddotMAX
EfjMAX
Minimum throat rndius = 100 mm
Rectangular shy Round Transformatioll
Eccentric Taper 225deg max in either plane Spliller are required for angles greater than 225deg and hould bi eet the angle between any side and duct centreline
DETATLS
Angled Offset
OUset Taper Splitters are required for angle greater than 22 0
and shoold bi eet the angl between any side and dUCI centrelinc
Mitred Offset
Concentrk Taper 2250 max in ither plane SpUtters are required for angle greater than 225deg and should bisect the angle between any side and duel c ntreline
Radiussed Offset
35
DW154 Splcilcuthm for Plastics Ductwork
STANDARD COMPONENT DRAWINGS ~ RECTANGU AR
Branch ducl DimCllsions widlh (W) (A)
urnl mm up lO 200 75
300 100 400 125 600 150
Ocr 600 200
FIG DRAWlNG DETAILS
56 poundplusmni~~ Rectan~lar - Flat Oval Transformation
57 [ Square Branch
58 er Angled Branch
Branch dUCI Dimensions wfdth (W) (A)
[- mm mm59 3shy Shoe Branch Up (0 200 75
--shy AIshy + 300 100
400 125
450 MAX 600 150
Over 600 200
Branch duct DimensIOn
rP X width (W) A)
60 - 1--shy _
~ mm mm
Bell Mouth Branch pto 200 75 300 100 t 400 125
600 150 Over 600 200
0=0 61 -
~ Bell Mouth
- shy T 4-5deg M x
--I 1-shy
TJ
62 X I ] I
Tele-scopic Joint I Illustrated with flangeL
X63
SBD Single Bladed Damper
36
---
DW154 Spedicatioll for Plastics Ductwork
STANDARD OMPONENT DRAWINGS - RECTANGULAR
DRAWING DETAILSFIG
64 on-Return DamperNRD shyshy
shyXbull
Multi-Leaf Damper Can be piggoted or flanged oppo cd or parallel blade
Alternative controls areshy
q p [gtshy
J HD65 Hand
~MD otori ed
PO Pneumalic
L-lt
l 13G 66 Blast Gate DamperX X
FireSmoke DampersSleeves
211r Ratinggtshy----
L_-
---
----
r----
Ir-- shy
IL- _-l
2hr
With i tallation frame
67 41 r Rating
4hr
Smoke damper SD
Intumc cent Sleeve L-d
37
DW154 Specijicutiolt for Plastics Ductwork
FIG
68
69
70
71
STANDARD COMPONET DRAWINGS shy REC ANGULAR
DRAVING DETAILS
gtshy Access Openings
AP 6 Access Panel - Rerno able
w [ ~ Access Door - Hinged
I ~le Inspection Cover
le -I reg -lt
~X X Flexible Connection
~ Drop Cheeked Radiussed Twin Bend
U Drop Cheek Bend
I
72 Air Flow SymbolX
38
DW154 Specifim[ioll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - ECTANGULAR
FIG DRAWING DETAILS
73
74
75
76
77
Q
Q
rp---t
~
V- I Ir---I
JL --11
THE ABOVE DETAILS TYPICAL PLENUM
Air Terminal Plenums
Plenum with side connection
Plenum with top connection
Cover plate with connection
Special plenum with connection
elescopic conn ction in direction of air flow
39
DW154 SpecijicotiOll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG
78
79
80
81
DRAWING
-23~---pound3-(MALE) (FEMAJE)
-t=j--_j(--d-shy
--L
~ THROAT RADI S= D AS T NDARD
e ~
THROAT Rjf)lU = D A MU)
DETAILS
Straight Duct With male and female connectors
Straight Duct With flange joint and slip joint
Bend MouldedIFormed Applies to any angle ego 30deg45deg60deg90deg Medium radius bend as illustrated Long radius similar but throat radius 0
Segmented Bend 90deg four section minjmum as illustrated
Other Angles 60deg = 3 sections 45deg = 3 sections 30deg = 2 sections
I
i
40 shy
DW154 Speciicafinll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG DRAWING DETAlLS
82 Segmented Twin Bend Radius = D2 max
May also be fabricated from tube
83 Equal Tee MouldedIFormed
84 -~ 1in Bend MouldedIFormed
85 Taper Concentric 1 0 as iUu trated Eccentric 30deg iJJcLuded angle
86 Short Taper
41
DW154 SpcUicatol1 for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG DRAWING DETAILS
87 30 max Offset
Angle Branch
Bran h dUCI Dimcnsions dia (D) lA)
Shoe Branch mm mm 88 Cl
Off rectanguJur Up 10 200 75 lOO 10 400 125
- 00 150 Over 600 200
Bl1IllCh duct DimenlOns din (D) (A
~-$a-Conical Branch mm mm
89 Also acceptable with Up 10 200 r
full conical surface 300 10
400 125
END VrE -shy 600 150 Over 600 200
90
m 75
100 12 150 200
mm Up to 200
_ 300 400
600 Over 600
iUtred Branch
Shoe Branch
J-L----U ~ Bell oulh Branch
ENDV1EW
93
92
91
42
DW154 Specificatiol for Plastics Ductwork
STANDARD OMPONENT DRAWINGS - CIRCULAR
FIG
94
DRAW G
I
~ 30deg 090deg
Breeches Piece
DETAILS
95 amp-----~ Blank End
~-----p Multi-Leaf Damper Can be piggolcd or fianged opposed or parallel blade
Alternative controls areshyri=-+- L-T~
I
---
LT~
I r- -
-+1
J HO Hand96
bMD Molori cd
PD Pneumatic
tl-shy bull
Single Bladed Damper 97 ~ saD
on-Return Damper Vertical application only 98 m~D
43
DW154 Sf1tcificatioll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG
99
100
101
102
DRAWING
$ I-
2hr
1 4hr
SD
~v I I
CO TINENTAL COWL
DETAILS
Iris Damper
Fi reS moke Dam persSleeves
2hr Ratillg
With installation frame
4br Rating
Smoke damper
Intumescent Sleeve
Access Openings
Access panel - removable
Access door shy hinged
fnspection cover
Discharge Continental Cowl
44
DW154 Sp(Cii(ltJll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
DRAWINGltIC DETAns
-
I
I
~
I I I High Velocity Discharge Terminal 103 I
I
I I
J I I 1 ~--
Offset Stack Discbarge Terminal 104 1
~ I e --(-
I
N
I
I
I~
I I Vertical Oischarge with Weather Cowl 105 I
--1--1 I
I
GAPI I
RTl AL DISC) lARGE WITH W ATIIER COWL
45
DW154 SpecUicatoll for Plastics Ductwork
STANDARD COMPONE T DRAWINGS - PLA TEQUIPMENTIMISCELLANEOU
FIG DRAWING DETAILS
106 ~~~ Rectangular Attenuator
107 ~- Circular Attenuator
108
~ Beod Attenuator
109 J ~(f) Heating Coil
110 J ftte Cooling Coil
III Jc[ Electric Heating Coil
112 X F
Humidifier
113 [H XX Axial Fan
114 ~fB1famp Noo-standard Ductwork Cross hntchillg (of any separate type) indicates by reference to a key any non DVil54 ductwork system
115 2llIIIIJIIIIIll Flexible Ductwork
46
DW154 SJeCUicll(iol1 for Plastics Ductwork
TABLE 12 - STANDARD ABBREVIAT ONS
ABBREVIATION FLL
AD Acces Door
AFF Axial Flow Fan
AHU Air Handling nit
All Aluminium
AP Acess Panel
AT Attenuator
AV Air enninal Unit
BE 81ank nd
BQ Blast ate Damper
CC Cooling Coil
CF Centrifugal Fan
CTA Cross alk Attenuator
CVU Constant Volume Unit
DP Drain Point
EEC Electric Heating Coil
El Expansion Joint
FAl Fresh Air Inlet
FA From Above
FB From Belo
fBPP Fabric Backed Polypropyl-ne Sheet
Flexle Flexible Connection
lexfD Flexible Du t
C False Ceiling CO an oil Unit
fD Fire Damper
FFL Finished Floor Level
FJ Flanged Joint
FOAM Rigid Polyurethane Self xtinguishing Foam
FOB Flat on Bottom
FOT Flat on Top
GAM Galvanised after ManufacttrJc
GRP Glass Reinforced Plastic
GSS Galvanised Sheet Steel
HC Heating oil
HD and controlled Damper
HH Hand Hole
HL High Level
HVD High Velocity Discharge
IC Inspection Cover
ID lri Damper
IFS Intumescent Fircleevc
47
DW154 Specification for Plastics Ductwork
TABLE 12 - STANDAR ABBREVIATION CONTINUED
ABBREVIATION
IU
L
tv1D
MS
NRD NTS
OBO
OE
PHD
PD
PP
PP
PRD
PVC
RFC
RSC
R
SBO
SO
S1 TST
SSL
TA
TB
TO TJ
TP
TV
TV
OS
UPVC
S
V
VAV
50 RSA
FULL
Induction Unit
Low Level
Motor controlled Damper
Mjld Steel
on Return Damper
at to cale
Opposed Blade Damper
Open End
Parallel Blade Damper
Pneumatic controlled Damper
Polypropylene
Self xtinguishing Polypropylene
Pressure Relief Damper
Polyvinyl Chloride
Rolled Form Chamlel
Rolled Steel Channel
R fUnit
Singl Blade Damper
Smoke Damper
Slip Joint
Stainl t el
tructural Slab Level
To Ab vc
To Blow
Top Down (In Direction of Flow)
Telescopic Joint
Test Point
TU111iog Vane
Top Up (In Direction of Flo )
Voles Otherwise Stated
Unpl3sticisecl Polyvinyl Chloride
Underside
Ultra Violet Light
Variable Air Volume
Rolled Steel Angle (Vith Size)
48
DW154 SJeriiflllioll for Plastics Ductwork
A2 DUCT PRESSUREAPPE DXA Ductwork con truct d to DWIl54 will bebullbullbullbullbullbullbullbullbullbullbullbullbullbull
Air Leakage From Ductwork To be read in conjunction with DW143 A practical guide to Ductwork Leakage Testing
CAUTION As highlighted ill both this docul1lenr and DW14 I lot ellough emphasis can be placed 01 the fact that except for high pressure class C the much more stringent ductwork constructional standard brolght about b the general acceptance of DW154 have irtlally negated the requirement for leakage-testing It is essential lO realise lhat except where it is mandatory this doclllllelll is nOl an endors ~lIlent of the rourine testing of ducts bllt purely a guide to outline the procedures for cononnity with the air leakage limits ill Table l Where the specified methods of assembly and
A3sealing of dlcls are u ed a vi ual inspection wil ordinarily sl~fll e for ver(iatioll of a well engineered and a ceptahfy airtight COl1strucrioll WHERE NOT MANDATORY DUCT LEAKAGE TESTING IS GENERALLY AN UNJUSTIFIED AND SUBSTANTIAL EXPENSE
A1 INTRODUCTION L akage from ducted air distribution systems is an Lmportant consideration in the design and operation of ventilatjon and air conditioning middotystems A ductviork t)ystem tbat ba limited air leakag within defiucd limits wiH cnsUft
that tile design characteristics of the sytem can be maintained It wilJ also ensure that energy and operatLonal cosb are maintained at optimum levels DucLwork constlucted and Ulstalled in accordance with DW154 should minimise a level of air leakage that it) appropriate to tll operating static air pre sur in tile system
A4However it is recouuised that tbe environment in wtJich middotystems are installed is not always conducive to achieving a predictable level of quality in term of system ajr leakage and it is therefore accepted that designer may sometimes require tlle ystem to be tested in part or in total It should be ecogni ed that the testing of duct systems add a ignificant cost to the installation and incur some extra tjm within the programme (Se 47 and 64 re mandatory te-sting)
manufactured to a structural standard that is compatible with the system operating pressure There are three classes of duct con truction to eorre pond with the three pre ure clas meations Class A Lo pressure ducts suita le for a maximum positive operating pressure of 500 Pascal and a maximum negative pressure of -500 Pascals Class B IVledium pressure ductmiddot suitable for a rnaxilnuJJl positive operafjn o pressure of 1000 Pascals and a maxllnum negative pre sure of -750 Pa cal Class C High pre sure ducts suitable for a maximum po ilive operating pressur of 2000 Pa cals and a maximum negativ pres ur of -750 Paltcals
LEAKAGE FROM DUCTWORK Leakao-e front pia tic air ducts occur at the joint~ and is therefore proportional to the total surface area orthe du twork in th system Tb level of leakage i imilarly related to tIle air pres ure in th du t system and whilst there LS n precis formula for calculating the level of air los it i generally accepted that leakage will increase in proportjon to pressure to rbe pOvver of 065 The effect of air leakage from high pressure velocit ductwork is critical tn terms of system perfomlan dege energy consumption and the risk of high frequency noise as ociated with leakage These problems are le critical with medium pressure 10 ity systems but should be con idered Low pres mevelocity ducts present the lowe~t
ri k in tenn of tbe effect of leakage on the operation of the s stern
SYSTEM LEAKAGE LOSS As there i no di ct relatLonship between th volume of air conv yed and the surface area f the ductwork sy tern required to match the building configuratmn it is difficult to express air leakage a a percentage of total air volume Similarly the operating pressure will vary throughollt lh 3 system and a leakage is related to pre me the calculations ar comple However it is generally ac epted tbat in typical good quaJjty systems the leakage from
49
DW154 Specificatioll for Plastics Ductwork
each class of duct llnd r operating condition will be io the region of CIa S A low pressure 6 Clas B medium pres un 3 Clas C high pressure 2
A5 SPECIFYING AIR LEAKAGE TESTING Re peeting both the co -t and programme implications a sociated with te ling du 1 for leakage the designer may for example indicate that a particular system is te ted as follow
a) High pressure ducts - all tested b) Medium pr ssure duets - 10 of the
ductwork shall be s eet d at random and tested
c) Low pre sure - unte ed In any case where a random te t i elected for medium pre sure ductmiddot the followin c1au~e is suggested for inclusion by the de ign r
The designer hall elect at random a maxirnwlI of 10 of the dUCl system to bt tested for air leakage The duct hall be tested af the pressure recommended in Table J3 for the assifi atiol for the ectiol1 of the ductwork that is to be tested The tests shall be carried Ollt as the work proceeds and prior to the application of thermal insulation In the event of test failure of the randomlY selected section the designer shall have The right to select two La1her e tiolls at random for resting Where succes ive failures are identified there shall be a Tight to require rhl COl11raCWr 10 apply remedial attention to the complete ductwork system Th contractor shall provide documented eviden e of the calculalions used to arrive (1
the allowable 10 I for the section to be tested and the client or his agent shall willess and sign the results of the test
able 13 Air leakage rates
Maximum leakage of duct work Static
prcssUft Low-pressure edium-prc-sure I Iigh-prebull me diJfercntial Class A Class B Class C
1 2 J 4 Pa Litres per second per quare metre of surface area 100 054 018 ZOO 084 028 300 110 037 400 132 044 500 153 051 600 058 019 700 064 021 800 069 023 900 075 025
1000 080 027 1100 1200 1300 1400 1500
029 030 032 033 035
1600 1700 1800 1900 2000
036 038 039 040 042
Note Recommend d mean test presures are highlighted iD bold type with the actual selection being left to tll test operator
50
DW154 Sfeeiieaioll for Plastics Ductwork
A9
A10
and air leakage classification for the y em under test
DESIGNERS CALCULATIONS The designer can middotaJculate with reasonable accuracy the predicted total loss from a ystem by
a) Calculating the operatin presure in each ection of the sy tern
b) Calculating the surface area of the ductwork in each correspondin pre lire s ction
c) Calulating the allowabl~ los at the operating pressure for each ection of the system (see table 13 for allowable leakage figures)
VARIABLE PRESSUR S IN SYSTEMS De igner can achieve significant co t saving by matchina operating pressures throughout the system to constmctional standard and appropriate air leakage testing eO the practice of specifying construction tandards for whole duct sy tems based on fan discharge pre sure may incur unnece sary costs on a project For example ome large sy terns ould well be classiC ed for I akage limits as follows
Plant room risers CJas C Main floor distriblltJou CIa B Low pre sure outlets Cla A
A6 SPECIAL CASES There may be ~itLlations on a project where circumstance dictate thal pecial consideration be given to containing air loss s eg a long mn of duclwork may incur a di -proportjonate level of air 10 s In ca es such as thi example the designer can specify an improved tandard of airtighmess ie 80 of alJo~able 10 s for la B Ju ts The designer sbould not specif a CIa C t sI at CIa s C pressure for a CIa s B ducl
A7 SUGG S ED RANGE OF TES ING
A8 TESTING OF PLANT ITEMS Items of inline pJant (eg Fig 106 to 115) will not normaUy be included in an air I akage test The dllctwork contractor may indud such itelllS in tbe te t jf rh quipm ot has a certificate of COnfOlnlity for Ihe pres ure clas
bull High pressure duct bull Medium pre sure ducts bull Low pre sur ducts bull Exposed extract syst ID bull Ceiling void extract
systems bull Secondary ducts from
VAV or fan coil units bull Flexjble duct bull Final connections and
branches to grille and diffusers
100 test See A5 Untested UDt sted
Untested
Untested Untested
Untested
SI
i
DW154 SJecijicafion for Plastics Ductwork
ig 116 Permitted leakage at various pressures
Leakage in litres per second per square metre duct surface area
Vgt
o ltgt 0 ltgt N
ltgt Cgt
0 0 cc
0 0
~
g =
g ~
c 0
J
ltgt 0 I
~ ] tn
ltgt ltgt
In ol
~ 0 ~ 8 ~
~
c ltgt ltgt
~ CJ
~ ~ ~ ~ 8
0shyij
~ ~ ~ t
ltgt ltgt 00
l
~
~ Q
c C
~ rshy
e ltgt
I 1
I Cgt ltgtv
c Co ~
~~ ~ 10
I
0 Cgt
fJshyq 410 ) 1 ltgt
ltgt N
~ shy ltgt ltgt
~ I 1
c
52
DW154 Specificatio for Plastics Ductwork
Example of a completed test sheet Test No
General
Name of job N~ jC43Pt(r2lef Building Repound ~(~~0
Part 1 - Physical details
a Section of duct work to be tested ~(diffPIfff~el1f3rd Floor
b Drawing Number g91~~ c ssure aSSJ L atlOn V~Jl~IRfYgtg~~lPre Cl T Class C
d Test static pressure -(9 raErq~ ~~~~-~~J~~~ ~~ ~~~~ll
Leakaoe factor 9~-tre3$ecMz I OM REFTOTABLE 13)e b bullbullbullbullbullbullbull
f Surface area of duct under test Q~tJJItetre$ CPROMCALCU TIO BELOW)bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull ampampamp bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull
g ]Vlaxi mum permitted leakage -~ (~i~~0 ~~r~~ ~~~l-~-11~ ~~~Q
Part 2 - Test particulars
a Duct static pressure reading 9QFt~q~ ~ middot~~~1 ~~
b Manufacturer and type of liow measuring d vice (-~~~cJ~Y-9Q7EYg c Range of measurement of now measuring device QtP)OQ~(e~~~0I~~~~1~I~ ~~~~~~W~
d Reading of flm measurin o device pmiddot IFROM RIO)ftscag ~
I (DERlVED [ROM CHART SUPPUED WITH RIG US 0 ud)1e Interpreted air flow leakage rate ~(~~~f~~~ (~l~~~~~~~~~~~~~~~~~I
f Duration ~~~~~norn~allY l~ lnil1Ut~~d~~~ it1~ W~ Date of test ~(lITled ut by Wltll s ed by ~ ~
(~lJ MIJLrr) (Si~rrfltJUYJ
Printed Name 1~g0f~ Printed Name ~~Y~9~ and Company 7jl~~~~~( UJd CompanY AB COII$Itallt8
Width and depth or diameter
Periphery ength Area
millimetreS millimetres metre qL1are metre
800 x 750 3100 1755 5440
600 x 650 2500 557 1193
300 x 300 1200 120 144
305 din 958 700 670
250 dia 785 450 353
TOTAL 8000
53
DW154 Specijilarion for Plastics Ductwork
pA XB
Guida ce No es For he ransport Handling and
Storage of uctwork
avoid damage to adjacent duct panels In somc ca es particularly on con acts calling f r repetitive sizes the use of timber jigs and spacers may be justified Where reduced bulk and greater protection are major factor such as consignments for export transporting ductwork in L shape sections may justify the increa ed ite as embly co ts
It is recommended that before a contract is finalised that consideration is given to the subject of site acces material handling and storage as tbcy havgt a strong influence on the cost efficiency of the overall activity of ductwOlk installation
B3 Handling To minilnise th risk of damage duct sections should be clearly identified and deliveries to site should be closely linked to the installation programme so as to avoid accumulation of
B1 Storage and Handling of Ra Material Material should be stored in suitably designed racking out of direct unJight Where possible the e racks should be metal to earth Edges of cut she t may be harp and protective gloves are advised Wearing teel toe-capped boots is recommended Most pIa tic sheet is manufactured with smootb mfaces andor is suppLied with protective coating Care must be taken to prevent accidental lippag of stacked materials Beiuoshy good electrical insulators the movement of stock unless earthed will allow the build up of stati All stock shapes are chemically stable at normal temperature Whil t some raw materials used in their manufacture may themselves pre ent a toxic hazard once incorporated into the lOck bape they no long r constitute such a hazard and no dermatitic bazard are known nor are any
unfiJied ductwork and minimise double handling It is important to recognise that ductwork panels joint and corners arc susceptible to damage and care must be taken wheu band ling such material through a site During handling individual item of duct work may be liable to light cross sectional deformation until thev become an integral pan of a completed ductwork system Whilst this may temporarily detract from its intended appearance thi deformation will not have any detrimental effect on the functionality of the finally a semblecl system Installation of duct work and asociated plant items ill illevitably involve manual handUng The responsibi Iiry of employers and employees to a ses the risk of personal injury during mallual handling operations is et out in the HS E publication L23 Guidance on Manual Handling Regulations 1992
environmental problems expected 84 Site storage
B2 fransport Large capacity vehicles with high-sided open or closed-top bodies are tlle mo t suitable for the transport of dllctwork Careful consideration should be given to the
Adequate floor space IDust be provided within tbe building for the site storage of ductvork Such storage shalt make due allowance for thc stOf(ne of ductwork in stacks such that access ~ egt
between them is of sufficient width to pennil the removal of item without interference to
unloading of transport on sit a not all siJes b n fit from the material handlino- and access facilities that exi [ in a manufacturing workshop such as crane- fork-lifts or loading bay Site handJiog facilities along with
adjoining sta ks Ductvork components should be positioned so a to avoid crushing Ductwork of small panel size may be stored horizontally however care should be exercised to ensure that tack sizes are limited 10 within
ehicular acce s restrictions may itilluence the type and ize of transport to be uWised
engtlls of ductwork should be positioned 0
the tmctural strength of the duct sections to prevent distortion of the lower sections within the stack
as to avoid crushing Lengths Witll projections such as branches and bends i1anges girths damper quadrauL should be loaded so as to
54
DW154 S1tciic(ltioll for Plastics Ductwork
85 Internal cleanliness of new ductwork The site storage of ductwork introduces the important cODsideration of maintaining the internal cleanliness of the ductwork R feren e should be made to HVCA documentshybull DWffM2 Guide to Good Practice - internal
Cleanliness of New Ductwork Installations If the above conditioDs can not be satisfied consideration should be given by tJle designer to amending the specification to include for Po t Installation Cleaning as covered by tJ1C HVCA documentshybull TRJ17 Guide to Good Practic - Cleanliness
of Ventilation Systems
APPE DIXC
Fi e Retardant inishes C1 Improvement in the fire retardancy of plastic
ducts can be achieved to varying degrees and is wholly dependent llPOll the surface coating laminating resin selected and construction specification adopted In some instances smoke emission is coILSidered equaUy with other speci fication requirernen ts of the materials resistance to ignition and bumjng It is therefore important for design rs to establ ish the clients and officers detailed requirements and not rely on a tbird party interpretation of fire resisting or fire retardant Where possible the specification should refer dir etly to compliance with a British or European Standard identifying the specific sections applicable There are various types of resin and mat rcLnforcements that can achieve a Class 1 surface spread of flame ratin o when tested according to BS476 Part 7 (1987) This test puts materials illto Class I - 4 in descending order of perfoDllance according to the rat and extent of flame spread over their surfac under standard beating conditions Materials should also be tested for flre propagarion to BS476 Part 6 (1989) Tbi tesr measures the amount and rate of heat evolved by the material when subjected to standard heating
conditions Test results are given as an index of Perfonnance (i) whicb is based on three sub indices (iJ (i1) (h) The higher the value of the Index of Performance (i) the greater is the material s contribution to fire growth The higher the value of the sub-index 0) rhe greater the ease of ignition aod flame spread The highest product performance classification as defined in Approved Document B of the Building Regulations is Class O This is acLlieved if a material surface of a composite ploduct i~ either a) composed throughout of materials of
limited combustibility or b) a Class I material which has a tlre
propagation index (i) of not more than 12 and sub-index (i l ) of nor more than 6
01 J Class 0 is not a cla$sif1cation identified in any British Standard test
There are resin system reported to be classified to Class O when tested to BS476 Pcl1S 6 and 7 however designers need to ensure that such sysrems can be applied to their proposed design In propriety resinmat system available the fabrication techniques and COITect application are critical to the integrity of the reinforcing and clas ificatiol1 For example in some systems the u e of a non-fire retardant gelcont on a fire retardant substrate would reduce the classification For further information see HVCA publication DW144 Appendix D
55
DW154 SplCijiClIliol1 for Plastics Ductwork
x Guidance otes For nspectmiddoton Servicing a d
Clean-ng Access Openings
D1 GE ERAL This appendix highlight in ummary fOI111
the acce considerations that hould be made by the design r iD terms of inspection servicing and cleaning Having considered the seop and the design of the dUCI work system relative to the guidelines outlined below the designer should clearly indicate which levels of acces should be incorporated into the manufacture of a new duct work system (See Table 14 and Note I b low it
D2 DESIGN CONSIDERATIONS
D21 In ptction and servicing requireshyments are set out in Section 15 of Lhis specification
D22 Cleaning requirements are set out in the HVCA pubUcation TRl7 Guide to Good Practice Clean Lines of Ventilation Systems and the guide tates The precise location ize and
type of access would be dependent on the type of ductwork cleaning inspection and te ting metbods to b adopted Care protection and standards of cleanliness prior LO cOlllmisionin o
are set out in th AV A publication DWITM2 Guide to Good Practice Internal Cleanliness of New Ductwork Installations and th guide state Wh re specific limits of cleanliness are required ductwork sball be cleaned after installation by a spcialist cleaning contractor It will b in the interests of tht desioner botb financially and practically to cunsider employing a specialist c1eauing contractor at tbe
outset of a contract to internally clean newly installed ductwork prior to bandover This approach would reali e the following benefit shyi) Tb actual numb r of cleaning
access panels could be detennined to suit the method of cleaning to be adopted (This may be 1 s than the maximum requiremen listed under Lev 13 of Table 14)
ii) Clear directions could b given to the ductwork contractor as to tJle size and location of cleaning access panels that are required to be fitted during the mauushyfaclunng pro s
iii) The specialist cleaning operation prior to commi ioning vould enable the cleaning contractor to verify the practical acee requirement for the future cleaning operation associated -vitb a regular maintenance programme
iv) A specialist cleaning operation prior to commissioning would allow the designer to omit from the speeilicatiolJ the DWrrM2 requirem nt for factory sealing protection wipe downs and capping-off
v) Specialist Ieall ill 0 to the measurable standard defin d in TR17 will allow an objective definition of cleanline to be achieved
Car ful consideration must be gIven by the designer to the practl aJ problems associated witb the manufacture and fitting of suitably si Led access panel on small cross section duct and on the circular faces of rouod and flat oval ducts in particular
D23 Special con ideration must be given by the de igner to the practical problems associated with gaining personnel access to heavily congested ceiling areas and multi-la red du twork systems This approach would avoid
56
DW154 Spfciication for Plastics Ductwork
the possibility of access panels being D3 ACCESS 0 IN-LINE EQUIPMENT incorporated into a ductwork system at the This appendix unly covers acc il1spection manufacturing stage that were later found in through the ductwork body adjacent to an item practice to be inaccessible for either ervicing of in-line equipment and not openings in the or cleaning activities equipment itself
able 14 Acce requirements for inspection servicing and cleaning
HVCA PUBLICATIO REFE NeE (uidtgt 10 Gund Prartict
Adjace t OW144 Cleanliness orVcnlillltio S~lcr~ fRjJ7
in-line LeyeJ 1 Level 2 Level 3 ite sequipment pcdionSen lcin~ Section d C1eaniJl( SUn(O)lnspc lion Palle ltk~m_n
2011 (minimum OiL Jubje-ct to duct ~zel (ft~ -Panels
Control Da pcrs One (inspection) 203 One 300 mm x 200 mm Both sid Fire Dampers One (sCTjdJl~) 20211 One 300 0101 x 200 mm One side HeatingCooling Coils One (inspedion) 20213 One 300 mm x 200 mm (lIpstream) Both sides Attenuators (rectangular) None required One 300 mm x 200 mm (downstream) Both sides Attenuators (circular) one retluired One 300 mm x 200 mm (downstream) One side Filter Sections One (inspection) 20212 one required Uoth sides Air Turn Vanes None requjred None required Both sides Changes of Direction None required one required One side In-Duct FansDevices One (inspection) 20213 None required Both sides l
1 In the absence of any indication by the designer only Level ) access will be jncorporated into a new ductwork system
2 Tbe panel izes associated with Lev lis I and 3 acee s ar e middottablished by reference to Section 20 of DW144 and Section 2 ofTRll7 respectively
57
DW154 Speclfifatio for Plastics Ductwork
pA XE
B-bliography Included in this Bibliography are technical pUblications which may be of interest (0 ductwork designers fabricators and erectors and to tho e in the heating ventilatlng air conditioning industries generally nquiric should be made of the relevant organisation at the address quoted Since its publication other addresse contained within 0V154 mav have changed and some pubJicalions may have been superseded
HEATING AND VENTILATING CONTRACTORS ASSOCIATION
4 Palace Court London W2 4JG Telephone 020-7229 2488 Fax 020-7727 9268
Orders fo FlY A Publications Old Matlsion House Eamont Bridge Penrith Cumbria CA 10 2BX (Telephone 01768 864771 Fax 01768 86718) Email hvcapoblicationshvwelfarecouk DWn 44 pe ilicatiun for sheet mctal duclwork (Iow- mediulllshy
and high-pressure) 1998) DWIl4 A practical guide to dUGI ork I akage te ting
(revised 2000) DWII54 Specification for plastic~ duct rk DW171 Guide to good Practice for kitchen venlibtion system DW191 Guide to good pracuce glass fibre ductwoJk DwrrMI Acceptance cheme for new products - Redangolar cro
joint classification Guide to good pra tice - Internal cleanliness of new ductwork installations Guide to good practice for the design for the Installation of lire and smoke uampers
J 1Other puhlications
HampV safely guide 5th edition JS2 Tool box talks JS5 Weldlng Safety booklet JSI9 afety facts bo klet Fact sheets 1-24 2nd edition JS2J COSHH manual volume 1 Advice on compliance with the
regulations 1521A CO I-rH manual volume 2 Asses mcnt h ets JS23 Ri k management manual TR3 BrazinltT and bronze welding of copper pipework cUld sheet
(I 976) TR5 Welding of carbon steel pipework (1980)
TR6 Guide to Good Practice for Site Pre sure Testing of Pipework (19 0) Guide to good practice cleanliness of ventilation Ylem
CHARTERED IN TITUTlO OF BUILDING SERVICES E G EERS Delta House 222 Balham High Road London SW12 9BS rTelephone 020-8675 5211 Fax 020-8675 5449) CIBSE Guide Volume A Design Data Volume B In tallatiol1 and quipment Data Volume C Reference Data
CommlssioniJIg Codes These Codes eover the preliminary checkS eUing to work and regulation of vanous catcgories 0 plan The Codes give a guide to design implications Series A Air Distnbution Systems Series B Boiler Plant
ri s C Automatic Conlrol ystems Cr1es R Refrigerating Sy terns
Sene iN Water Distribution Systems
Technkal Memonllda TM 4 Design Notes for the Middle East TM bull Design otes for Ductwork TM 13 Minimi iog lhc Risk of egiounaires Disease
Research Reports RROI95 Ventilation system hygiene - A review of published
infomlatioo on lhe occurrence and ffects of Olltamination Rl~02J95 Air-to-air heal rec v ry RR0395 rnfluen e of HV C on smoke detectors
ATlONAL ENI [ERING SPECIFICATION LfMITED Southgatc hamber 3739 Southgate Street Winchester S023 9EH (Telephone 01962 842058 Fax 01962 R(8982) BUfLDING S RVICES RESEARCH AND [ ORMATION ASSOCIATIO Old Bracknell Lane West Bracknell Berkshire RG 12 4AH (Telephone Brackl1eU (01344) 426511 Fax 01344 487 -7 )
Application Guides AGln4 De tglJing Vana~le Volume middotylans for KOOnl
iir Movement AG1I91 Commissioning of V Sylcms in Buildings 11 6194 Fire Dampers
B) 94 cntiJalion or KitcneTls
AG389 The Commls ionin of Air Systems In Buildmgs AH2192 Commissioning of Bern - A ~ode of Practice TN2417 I Fire Dampec il) Ventilating Ducl
BEATING VENTILATING A AIR CONDITION G MA UFACTURERS ASSOCIATIO (HEVAC) HEVAC Henley Road Medmenham Marlow Buck SU 2ER (Telephone 01491 578674 ox 01491 575024 Emoimiddot infofetacouk)
Publicatjons Air Diffusion Guide Guide to Air Handling Unit Leakage Testing Guide to Good Practice Air Handling Unit Real Room Acoustic ~ st Procedure Specification for the ertiiicatioll ofAir Filters Method of Test for Water Rejection PerfOnTlatce of Louvrcs Subjected 1(1
Simulated Rainfall Test Procedure for Acoustic Loo cs Specification 10 Floor GrilJes - Types Performan e and Method ofTest Specification for the Determination of the Collection Efficiency of SilJ1d
Trap Louvre Domestic Mechwlical Vclltllalion Systems with Heal Recovery Fan Application Guid
~an and Ouctwork Installation Guide Guide to Fan Noise and Vibration
pecification of Requirements for JallJral Smoke and Heal Exhausl Ventilators
pecification for Powered Smoke and Heat Exhaust Ventilators
Specification of Requirements for Smoke Curtains Design Gujue of Smoke Ventilation for Single Storey Lodustrilll Building~
Including those with Mezzanine Floor and IIi Racked Storage Warehou es - Issue 3
Guidance for the Design of Smoke entilation YSlem for Covered and Undergrollnd Car Parks - lssue 1
Application of SOloke Control Equipment and Syst m Guid to Good Practice - Isue J
58
DW154 Sp(C~tiifitiol for Plastics Ductwork
BRITISH STANDARDS INSTIT TION Sales Department 101 P ntooviLle Road London NI 9ND (felephone 020-78 1 78801)
CP 413 1973 Ducts for building ervices
SS 476 Fire tes on building matenals and lruc(ure
Part 4 19 4 Non-combustibility lest or materials
Part 6 I Fire propagation lest for materials
Part 7 1993 Surface spread of tlarnJ tesls for materia
Part 20 1987 Fir resistance of elements of construction
Part 21 1987 Fire r sistlUlce of loadbeanng elements of construction
Part 22 1987 Fhe istallceofllon-loadbearing elemcllts ofconsttuclion Part 23 1987 Contribution of componcnts to the fire resistance 0 a
structure
Part 24t987 Fire resi lance of wl1lilation ductl
SS 5588 nan 919 0 Fire Precautions III thc desIgn and OOSlnJ lion of buildings
S 729 1971 Hot dip galvanized oatiugs (or irOIl aod stcel articles
BS 1449 Steel plate sheet and Irip
Pan 11991 Carbon steel plate heel and strip Part 2 1983 Stainless steel plate sheer and strip
and
B middotENJOI49-2 996 BSEN 10149- 1991)
BSEN 10131 1992
BSEN22063 Sprayed metal coarings 1994 Protection of iron and steel by aluminium and zinc against
atmospheric cOlosion Irotectiotl of iron and ste I against corro ion and oxishydation at elevared temperatures
BS 353 1981 Glossary of lerms relnting to thermal insulation
BS ISO 1479 Self-tapplngscrewsandmetallicdri c crew
B -lSO 7049
1994
B 4800 1989 Painl colour for building purposes B 4848 l0 rolled structural steel sections
Part4 1972 Equal and unequal angles BS 5422 1990 Specification for the use of therm illuating matcriulS
SS 5720 1979 ode of practice for mechanical veutilating and air C 11shy
dirionin bull in building
l3S PR 12814-1 Bend resting for plasric welds
SS PR 12814-2 Tensile testing for plastic welds
SS PR 13067 Appro altesting for plastic welds
BS PR EN I 100-] Vi ual in pection ofplaslic welds
SHEET METAL AND AIR CONDITIONING CONTR-CTORS NATIONAL ASSOCIATION INC (SMACNA) Headquarters 420 I Lafayeue Center Drive Chanlilly Virginia 2051-1209
Mailing Address pa Box 221230 Cbantilly Virginilt120 153-1230
Telephone (703) 803-2980 Fax (703) 803-3732
Accepted IJJdustry Pl3Gtice for Industrial Duct Constnlelion 197 ) i-rchitecmral Sheet kwl Manual ([993)
Comractors Guide lor Modification 10 ooslruerion Colllraets 1993 Ducted Eleclric Heat Guide for ir Handling Ssrerns (1994)
En~rgy ollservatioD Guidelines (1984) Energy Recovery Equipment yslClllS (199l
Fibrou GIns Duct onS1ntClion Standards (1992)
Fire Smoke amp Radiation Damper In tall Guide for HVA Syst ms (1992) Guide t leel Stack 1(95)
HVA Air Duct Leakage Test Manual (19 ) HVA COlllmissioning lvlanual (1994)
H A Duct Construction Standards-Metal amp Flexible (1995) Addendum 01 (Nov 1997)
HVA Duct Systems Inspection Guide (1989)
HVA ySlems-Application (1986) nVAC ByternS-DLlct D ign (1990)
HVi Systems-Testing Adjusting amp Balancing (1993)
indoor Air Quality Manual (1993) tcheu quipment Fabrication Guidelmes (1990)
Managers Guide for elding (1993)
Rectangular Industrial Duct Cons1TUction Standards (19 0) Round Industrial Duct oustmction Standards (1977)
Sei mic Restraint Manual (1991) (wl Appendix E 1993) SMACNA Ma le Index ()fTechnical Publications (1995) Tbennoplnstic Duct CPY ) Construction Manual 1994)
DEPARTME OF THE ENVIRO MENT (Publications Centre) H Stationery Oflice 5 Nine Elms Lane London SWS 5DR
MampEJ 011972 Electrical in tallat1011 in buildings ( ew Editiou)
IampE 0319 Healing hot and cold wat r steam and gas losla1lations for buildings
M amp - No4 1970 Central heating and hot and cold ~ ateT in tallations for
dwelling
M amp ENo100 1971 Mechanical ventilation for building~
ASSOCIATION FOR SPECIALIST FIRE PROTECTlO As ociation House 235 Ash Road AJdershot Hampshire GUl2 4DD
Telephone OJ25221322 Fax 0 J252 333901
lublicalioos Fire Ratcd and moke Outlet Ducrwork An Industry Guide t Design and InSlalla lioll
HEALTH AND SAFETY EXEC TIVE Rose Court 2 Southwark Bridge London SEl 9HS Telephone 020-7717 6000
TWJ THE WELD G TlTUTE Abington Hall Abington Cambridge CB16AL Telepbone 0 J223 89162
Publication DatJ Oil w~ldll1g of lhermopla lics
59
DW154 wciiwlioll for Plastics Ductwork
A -=--DIX
Factors
Specific gravity shy pp = 091 approx UPVC = 14 approx
Some miscellaneous conversion factors
To convert
Length Inches to millimetres Feet to metres
Multiply by
2540 03048
To convert
Millimetres to inches Metres to feet
vIultiply by
003937 3281
Area Square inches to square millimetres 6452 Square millimetres to square inches 000155 Square feet to square metres 00929 Square metres to square feet 10764
Volume Cubic feet to cubic metres Cubic feet to litres Gallons (UK) to litres
002832 2831 4546
Cubic metres to cubic feet Litres to cubic feet Litres to gallons (UK)
35315 00353
022
Mass Ounces to grams Pounds to kiJograms Tons to tonnes
2835 04536
1016
Grams to ounces Kilograms to pounds Tonnes to tons
003527 2205
09842
Volume flow Cubic feet per minute to cubic Cubic metres per second to cubic
metres per second 0000472 feet per minute 2119 Cubic feet per mIDute to litres Litres per second to cubic feet
per second 04719 per minute 2119
Motion Feet per minute to metres per second 000508 Metres per second to feet per minute 197
Pressure Inches water gauge to millibars 2491 Inches wateJ- gauge to pascals (Pa) 2491 I Pa = I ewton per square metre = 10-2 millibars
60
Heating and Ventilating Contractors Association Esca House 34 Palace Court London W2 4JG
Tel 020 7313 4900
e-mail contact Itvcaorguk web site wwwhvcaorguk
Fax 020 7727 9268
DW154 Speci(uariml for Plastics Ductwork
Fig 9 Turning Vanes
HOWl G TYl AL EXAMPLE OF FOCI G
15
Ma vane length shy 615 mm
Example ofbraemg when V1IIle length exeeed max pennined Ahematively two banks of ncs fixmg the centre rail together at ] 50 mm nrrcs
U~_II---- fixed to dnct wall both CDds
bLEVATION
vane
Maximum distance between centrc oflUming vanes should [Jot exceed 60 mm pitch
DW154 SPCCijicllfiull for Plastics Ductwork
practice to provide common terms ofPA T4 reference for designers quantiry urveyor and
Circular Ducts
12 CIRCULAR DUCT SIZES Th duct sizes [n Table 4 have been selected from the ISO and C standard ranges as the 132 preferreod sizes
Table 4 Circular ducts shystandard extruded tube sizes
133 Extruded tube
ISO Standard Sizes (Nominal Diameter) 11
Wan Wall Thickness Thickness
mm mm mm mm 110 500 4022
I25160 600 50 I25200 630 60
225 25 700 60 13425250 800 63
280 900 70 315
23 23 80
355 1000
25 1250 104 400 32 1400 108 450 35
Note The above sizes are subject to normal manufactl1ring tolerances Other size may be available in varying wall Lhicknesses and subject to test and operational pressure
13 CONSTRue ION
13 General Tllis specification covers duct sizes up to a maximum diameter of 1500 mm The minimum constructional requirements for UPVC amp PPPPS un-reinforced ducts sball be as Tables 6 amp 7
ductwork contractors and tho e using computers in ductwork design and fabrication The requirements for circular duct fittings apply throughout the size ranges covered in this specification
Sheet jointing seams Seams shall be joined either by continuous fLiJer rod hot air welding or by fu ion welding Other forms of jointing are not acceptable
Socket and Sl)igot joints Socket and spigot joints shall be formed by purpose made double socket pieces 100 mm long and of the same thickness material as tJJe duct welded into position on each tandard length of duct forming 50 mm deep sockets prepared and ready for final jointing on ite with PVC adhesive andor fill r rod of the same formulation used for fabrication
Flanged joints
1341 Flanges abricated flanges shall be conshy
structed using minimum of 9 mm thick by 50 mm wide material of matching formulation depending on duct size as shown in Tables 6 amp 7 The flange shall be mounted true and square to the duct surfaces and welded OD both sides a 103 and Fig 12
1342 Drilliogs Drilling ball be placed to permit clearance to the external casing and any reinforcement of the ductwork
1343 Fastenings For normal application bright zinc plated bolts nuts and washers hall
16
For srualler diameters preformed fittings are available otberwise fitting are fabricated from segments of duct or sheet welded together
The terminology and description of circular duct tiltings as set Ollt in Section 25 are recommended for adoption as standard
be used in sizes and pitCh centres shown in Table S Wh re special conditions prevail consideration of other material finishes such as stain le steel bolt nuts and wasbers shall be u ed In all ca cs gasket materials as Seciion 825 shall be USed
DW154 Speciliwriml for Plastics Ductwork
135 Stiffeners
1351 External stiffeners Shall be fitted as specified in Tables 67amp 1 I and Fig 13
1352 Internal stiffeners The use of internal stiffening or bracing hall be acceptable if deemed neces ary and appn ved by the designer
f 36 Expansion joints Where the corrfiguration of the ductwork does not provide for movement due to temperature
Cross joints - circular ducts
change or where such movement is restricted by branches or attachments expansion joints should be fitted (See Section 18 Flexible Expansion joint connections)
It is the responsibiLity of the designer to identify the position of any necessary expansion joints based upon design parameters for the individual systems (See Figs 23 24 2534 amp 35)
Design Note Examples of expansion joints shown are not suitable for movement exceeding 30 mm
Fig 10 Socket and spigot joint (UPVC and PP)
ConLinuous weld joim on ite Ontinuous weld
crlr~l
Fig 12 Flange joint (UPVC and PP)
Continllous wcld
boil
Continuous weld or Solvelll cement
Solvelll ccmcnl joim on sile
Fig 11 Socket and spigot joint (UPVC only)
Stiffeners - circular ducts Table 5 Fastening centres shycircular duct flange jointsFig13 Flat
flat conljnlJou~ly welded Diameter Pitch Bolt Size
max
1 2 J 11
1 shy -~
mm mm mm Up to 600 100 8 with washers
601middot1000 100 10 with washers - ---I
1001middot1500 100 10 with oversized washers
1
Minimum offourfixings
17
DW154 Specifiiutiofl for Plastics Ductwork
Table 6 constructional quiremen s - circular unshy inforced U VC
Diameter Minimum Joints Stiffeners Maximum spa ~in r
Sheet between Thickness Jointsl tiffcners
1000 Pa 1500 Pa
1 2 3 4 5 6 UD mm mm mm mm
UO to 600 3 socket amp spigot as Figs 10 11
or fla ged Fig 12
601 to 1000 45 socket amp spigot 50 x 9 flat 2400 2400 as Figs 10 11 welded bo sides
or Oanged as Fig 13 as Fig 12
1001 to 1500 6 Hanged 75 x 9 flat 1200 1200 as Fig 2 welded both ides
as Fig 13
Applies 10 Tables 6 alld 7
Note 1 For constructional operating temperature limit refer to Part 2 luu 54 2 To allow for conicleration or extruded se lions or fabricated component the materia] tllicknes i hawn a nominal
Table 7 Minimu onstrucfional requirements shy circular un-reinforced PPS and
Diameter Minimum Joints Stiffcners Maximum pacio Sheet between
Thickness Join sStiffener 1000 Pa 150n Pa
I 2 3 4 6 mm m m mm
110 to 500 3 socket amp spigot as Fig 10 or flaoged as Fig 12
501 to 750 45 ocket amp spi~ot
as Fi 10 or Uanged as Fig 12
751 to 1000 6 tlanged 50 x 9 Oat UOO 12 0 as Fig 12 welded nth sides
as Fig 13 1 1 to 1250 6 flanged 75 x 9 flat 800shy 800
as Fig 12 welded both sides as Fig 13
1251to~ flangcd 75 x 9 Oat 600 600 as Fig 12 welded both sides
as Fig 13
18
DW154 Sped(icalirm for Plastics Ductwork
PARTS
Hangers an Suppo ts
14 GENERA
141 Supports are an e sentiaJ part of me ductwork system and their supply and in tallation are normally the responsibility of the ductwork contractor The principl s are a I-rvCA publication DWIl44 Part 6 Section 19 and should be read in conjunction with this document
Design Note Designers may pecify specific requirements wbich will supersede guidance given in DW144
142 Rectangular ducts abl 8 give the- minimum requirements for
hanger and supports for un-reinforced ductwork
143 Circular ducts Table 9 gives the minimum requirements for hangers and upports for uD-reinforced ductwork
144 Vertical d cts The design of supports for vertical duct is dictated by site condition and where practical duc hould be upported at 4000 mm interval or where tbey pa s through a floor (but n ver exceeding 4500 mm) see Figs 17 amp J8
145 External ducts Where ducts are external to buildings and may be ubject to wind loading support should be plac d so as to restrain ide tl1ruSt and should allow axial movement as neces ary It is the respon ibility of me de igner to calculate the effect of the particular prevailing condition and to define any special upport requirement
146 Expansion joints Support shall be designed to permit axial movement only and shall e provided on eitl1er ide of expansion joint
I 1shy
I~
mm -Jp to 400
401 to 600 601 to 1000
Table B Hangers and Supports - rectangular horizontal ducts
Hanger Bearer Drop Roll Formed Rod
Long r Side
Cbannel ~-shy ~
---shy
Maximum ~pacing
4 52 3 _ -c Fig 15 - Figs 14 15 16 amp 2J
shy
mmm mmmm 240025 x 25 x 16 40 x 20 x 15 8 240040x20x15 40x 20 x 15 10 240040 x 20 x 1~510 40 x 20 x 15
shy
I
40 x 40 x 15 40 x 40 x 15 24001001 to 1500 I 10
Table 9 Hangers and Supports - circular horizontal ducts
Longer Side Hanoer Split Clips Maximum spacing Drop Roll f-ormed and Wrap-round Rod ~hannel Hang r
2 3 4I Fig 1920 amp 22Fig I
mm mmmm mm mm 25 x 25 x 15 IIp to 355 8 40 x 3- --1-_ 2400
2400
2400 2400
70x 6
40 x 5 SOx 5
40 x 20 x 15 40 x 20 x 15 40 x 40 15
10 10 10
356 to 600 601 to 1000 1001 to 1500
19
DW154 Spccijicutioll for Plastics Ductwork
147 Protection specification Any special coatingpaint Unless otherwise stated all support shall be finishes for protection against hostile manufactured in material as specified in this environments shall be advised by the designer
SUPPORT BEARERS
~ 14 Flg16 Inverted profile
angle I ~lIed steel
channel (alternatives) Fig 15 Profile channel (alternatives)
TYPICmiddotAL VERTICAL DUCT SUPPORTS Flat bar clipStiffening frame Outline ofinsulation stiffening frame or tlanged joint (if applicable) or flanged joint
Stiffening framc or flanged Joint
~~-I ( ee notes 10) I
r--~ -++- ~--4==J===4~---
Fig 17 Vertical rectangular ducts Fig18 Vertical circular ducts
The support bearer which depending on ducti tructural opening size could be either channel or angle section may be ll1ilised in any of the following arrangementsshy
a) To support the underside of a flat bar clip in halves (circular)
b) To support the underidc of either the stiffening frame oftbe flanged joint ofaoy duct section
c) To support either a stiffening frame Or a flanged joint below nsing drop rod srudding
20
DW154 Spediraiml for Plastics Ductwork
Arrangement of bearers and hangers (to be read in conjunction with Table 8 amp 9
wbich list material sizes relative 10 duel izes)
KEY Limits refer to actual duct size - insulation is additional - Typical
attachmentv -Atta hment t strucUlrcI to strucUlrc
I I
I - Flat Bar
I - Drop rod or - utlinc of lllddmg In ulillwn (if
applicable)
Alternative 7 drop rod or rt------------ 1 studdmg q I
I I Rectangular
ii i n 1
Fig 21 Rolled or profiled bearer Limit oncFig 19 Wrap-round hanger Limit 55 DIA
V v Drop rod orAllernaUC 1 1 tudding
drop rod or 1
-- -- 1studding and elded bas 1
I I0 -_
Limit 355 DIA Frg 22 Split clips Limit 1500 DIAFig 20 Flat strap hanger amp split clips
21
DW154 Specification for Plastics Ductwork
6PA deElned in J62 appropriate to the airflow pressure acoustic temperature and corrosion
General
15 ACCESSl SPECTION OPENINGS
151 General These are for inspectionservici ng on 1y
HVCA publication DWIl44 Part 7 - General Section 20 sets out the requirements for access applicable to this specification
152 Cleaningmaintenance Designers shall take specialist advice and then stipulate their requirements for the periodic internal cleaningmaintenance of ductwork and of the consequent need for adequate access for specialist cleaning equipment including the size type and locationfrequency of the actual access openings required
Appendix D sets out guidance notes for the consideration of cleaning access and also makes reference to the HVCA publication TR 17 Guide to Good Practice Cleanliness of Ventilation Systems which covers the su~ject
in greater detail
Note A majority of in tallations in which plastic ductwork is used are considered to have a nigb operational risk potential and provision of access should address this
16 REGULATI G DAMPERS
161 General Balancing dampers and control dampers are elements inserted into an air di tribution system or element of an air distribution sy middottem Balancng dampers permit modification of the air resistance of tbe system and consequently cbanging of the airflow rate Control dampers control tlle airflow rate and may in addition provide low leakage closure of the airflow
The deigner shall specify damper locations taking into consideration that good design practice requires a minimum of five times the diameter or width of the shortest side of uninterrupted flow between plant connections and the damper and select the damper type as
characteristics
1611 Balancing damper To achieve the required distribution of air in the ductwork system at inlets andor outlets for [hi purpose the damper blades are set and Jocked manually in position between fully open and fully closed
1612 Control damper To secure dynamic control of the air now in the ductwork system In thi function the damper will always be power actuated and may require to be modulated between fully open and fully closed and to be capable of taking up any position between these extremes In the fully open position the damper should have a minimum pressure drop In the fully closed position it will not necessarily achieve a complete shut off
162 Types of airflow control dampers Airflow dampers of various types are available for specific purposes as follows
1621 Single - blade dampers Single-blade dampers shall consist of a si ngle pi voted blade cOlllained withjn a casing or section of ductwork The blade shall be adjustable tbmugh a nominal 90 angle by means of a quadrant or similar operating mechanism Where automatic control of the damper is required the spindle shall be extended to enable a powered actllator to be mounted
Single-blade dampers shall have a maximum duct width of 400 nUll and a maximum duct height of 400 mm for rectangular ducts and for circular ducts a maximum diameter of 400 mm
1622 Multi-blade dampers Multi-blade dampers shall consist of a number of pivoted blades contained within a casing The blades shall be
22
DW154 Sedicalirm for Plastics Ductwork
adju table through a nominal 90deg angle simultaneously by intershyconnected linkage or gears connected to a quadrant or similar operating mecbanism Where automatic control of a damper is required a spindle shall be extended to enable a powered achlator to be mounted
There is no restriction on the size of duct in which multi-blade dampers or damper assemblie may be u ed Where dampers are required for blade lengths in excess of 750 mm the blades should be suitably reinforced or supponed 0
individual damper blade should exceed 200 mm in width
1623 Iris dampers Lris dampers shall consist of a nUlllber of radialty interconnected blades which open or close within a casing with duct COlll1cctions The blade shall be simultaneously adjusted by a quadrant or similar operating mechanism
Iris dampers shall be installed as specified by the manufacturers operating and installation instructions where the product is unidirectional with regard to airflow
lris dampers are available for circular ducts only in diameters up to 250 mm (it should be noted that the damper casin i appro)(imately twice the diameter of the duct)
1624 Backdraught dampers Air pressure operated uni-directional rectangular (single or multi-blade) with adapters if fitted to circular ducts
1625 Slide and blast gate dampers A damper [lsed as a shut off facility with an externaJ Lide bousing allowing the blade configuration to be fuJly inserted to fully extended for maxiDlUlll air flow
163 Construction
1631 Materials All products shall be protected against cOHosion as necessary and supplied in a fully finished condition as specified by the designer
1632 Dampers used in low and medium pressure systems The following recommendations apply to dampers forming an integral part of ducrwork with pressure classifications A and B air leakage limits
The dampers shaH be constructed to minimise distortion and prevent jammin in operation Th blade shall be sufficiently rigid to minimise movement when in the locked pOSitiOLl
The blades shall be securely fixed to the operating mechanism All balancing dampers shall have a locking device located on the outsid of the case and shall giv clear indication of the actlwl blad position All penetrations of the duct shall be fitted with suitable seals where necessary
1633 Dampers used in high pressure systems Regulatino- dampers used in duc[work sy tems to pressure cJassification C shall meet tbe construction requireshyments specified in 1631 and 1632 with operating mechanisms out of the air-stream
1634 Proprietary types of damper The use of any specific type of proprietary damper shall be confirmed by the designer In all cases proprietary dampers shall meet the relevant requirements of thi specification
1635 Damper casings Duct damper casings hall be constructed to meet th mllllmum
23
DW154 SpeciJimlioll for Plastics Ductwork
leakage Iim its sp cified for th c1uctwork ystem to which tbey are installed
In order to apply the square metre leakage calculatio as detailed in DW143 A Practical Guide to Ductwork Leakage Testing the reference casing area ball be taken as the perimeter ize of lh damper IDultipli d by the equi alent length of Imetr eg an 800 mm x 400 mm duct damper hall have a surface area for casillg leakag p donnan calculated as follow (2 x 08) + (2 x 04 x I
=24m2 casing area
Other pelforlllance ancl rating test methods for damp f and valves are specified in ISO 5129 and BSIE 1751 and are referenced belm a) Leakage past a closed damper
alve BSIE 1751 b) low ratepre sure requirement
characteri t cs BSIE 1751 c) Operational torque le ring
BSEN 1751 cl) Thermal transfer testing
BSIEN 17 I e) Reg nerated sound power levels
ISO 5129
164 Installation Dampers shall be imaalled in accordance will) any re Ievant ISO EN or British Standard 10 aJ bUT lcling regulation and national code of practice as well as the manufacturers recommendations
17 FIRE DAMPERS AND INT MESCENT SLEEVES
171 General Damper or sleeves arc requiTed on duct y~telll where the designer has -tjpulated the
duct wiU penetrate a fire compartment in the majority of application tbermopla ti ductwork is ugtecl where contamlDated corro ive or otherwise exceptional fumes are concerned it is preferable to use tire damp r which are externalJy mounted ie of the intmnescent operated crush typ
24
72 Fit-e rating The damper assembly should have a fUT
resi tance ratin o equal to that of the fir ban-jer it penetrate and ball be fire tested and rated to the timetemperature curv of B 476 Part 20 and 22
173 Intumescent sleeve At the time of writing this specification qualified test results were available for rectangular dampers and circular dampers up to 55 mm diamet r Manufacture have indicated that they are able t provide speci fications for other size and diameters This infonnation should be confirmed b th de igner Various type are available includino
tho e incorporating ruechanical closing plate and those operated anI by expanded iJllUme c nt media
In all ca es fire damp rs and intnmeBcen leeves shall be supplied and in taUed in
accordance with the manufacturer iJlStructioos and COSHH a essm nt
174 Other types Fire dampers of mious types are availabl for specific purpose~ ee HVCA publication DW144 The de igner should )lot (hat materials for con lt1Jction bould be uitablc for the par1icular application
ALL C SES FIRE DAMPERS AND fNT MESCENT SL _VES SHALL HE S PPLTED AND INSTALLED IN A ORDA CE WITH Tf--IE MANUshyPACTURERS STRUCTTONS AND COSHH ASSESSMENT
18 FLEXIBLEEXPANSION dOINT CONNECTIONS
181 General ploperties Tbe material u ed for flexibleexpan ion iojnt~
mu t meet the design r requirements for temperature air pressllrelfe resistance applicable to pl astic duct sy tem vibration and noi e br akout when incorporated into a jointconnection and shall comply ith lh standard of air-tigbtne specifi cl for the duct work sy tem of which it fOlms part (See Figs 23 24 5 26 27 amp 28 for typical con truclion clelai Is
DW154 SJecilimtol for Plastics Ductwork
Expansion joints
Fig23 Moulded bellows type (rectangular and circular)
Fig24
~F aiblc sleeve
__ liding sleeve
~~~~
Sleeve type (circufar)
Fig 25
AIRFLO
COnlinuou~
weld~
Flexible Iceve
PV A HOWN pp SE BACKING FLATS AS FIG 2
Sliding lee c Co1linuou
weld
Flanged sleeve (rectangular and circular)
25
DW154 Specificatiol for Plastics Ductwork
Flexible con ections
Fig 26 Flexible sleeve with clips (UPVC and PP)
--__ Flexible I eve
I
I
I CODn clioD to plant ~
Band clip
Fig27 Welded flexible sleeve (UPVC only)
Plastic)sed PVC slceve ~-- onll11uo1sly welded
onrreclion to planl ~
Fig28 Flanged flexible connection (UPVC and P )
t sp dally moulded flexible flanged connCClitlll
boil
C)nneclion to plant ~
26
DW154 Specificotiol for Plastics Ductwork
182 LOClt1tion Flexible joint are typicltllly lIsed at building expansion joint and fan inletsoutlets Any others required should be indicated on the de ign drawings Care should be taken to maintain alignment across jointsconnections
183 Length Flexible Jomts shall be kept as short as pra middottieable above a minimum eft ctive length of SO mm In no ca e shall a flexible joint exceed 250 mm in lengtb
184 Connections to rectang a ducts With flanged rectangular connections Ule tlexible material shall be held in pLace with flat pIa tic strip of not less U1an 6 mm thick ltlttached to the flanges using uitabJe fixings The more heavy weight type of fleAible mateLial may also be obtained formed into a channel ection with corners fitted to give a neat air tight j int For pigot connections the Be ible material shall b held in place with flat pIa tic trips n t less than 6 mm thick
t 85 Connections to circular ducts With tlanged circular connections the flexibl material shall be held in place with flat plastic backing strips or proprietary clip bands with screw or toggle fast ners
186 Welded flexible connections (Rectangular and Circular) Where the parent and llexibl material are from imilar ba ed products they can be joined to the duct u ing the welding method described in Section 823
19 PROTECT VE FINISHES
191 nles otherwise stated all ductwork shall be mallllfactured in mat fial as pecified in tbis specification Any special coatingpaint fmishes to be provid d by the duct work contractor sball be advisd by th de igner
20 CONNECTIONS TO BUILDING OPENINGS
201 Fanning and finishing building op nings are not the repoJlsibjlity of the duftw( rk contractor and the note that follow are for guidance purpo e only
2011 Openings in brick block or concrete walls shall have inset frames to provide a suitable means of fixing grille louver masking flanges or the tlanged ends of ductwork The illset frames shall be conslnlcted to maintain the structural int grity of the wlll and where applicable cavities shall be suitably lined
2012 Openin s in dry linino partItIons shall have inset frames a 2011
2013 Openjngs in cladding walls and roofs shall have flaoged leevesframes to provide a suitable means of fixing a 2011
2014 Horizontal and vertical opening xposed to oLltside atmo phere hall
be provided with a suitable weathering fini h at the external face especially where profiled cladding is used
2015 Timber framed op nings are not permitted In fj re compart ment barriers
202 Ductwork connections to building openings hall have a flange of suitable profile to permit practical fixing to the openillg frame In selecting the profile consideration shall be given to Tabl~s 2 and 10 in this specitication relating to duct ize and rating Gasket strip or sealant shall be ltlpplied between the tJaoge and building op ning frame
21 DISCHARGEEXHAUST TERMINAL
21 Tbese shall be vertical open ended and designed to meet and comply with current r gularions on contaminated flue The designer hall ensure that the de ign and perf rmance i suitable for its intended purpose Examples of some typical terminal designs are SbOiD in Figbull 102 10 bull 104 amp 105
27
DW154 SpedjimioTl for Plastics Ductwork
22 THERMAL INSULATION
221 The provision and application of thermal insulation to ductwork is not the responsibility of the ductwork contractor
222 Where ductwork is required to be preshyinsulated the specification should be agreed with tbe designer
223 Where the temperature of the air within the duct promotes condensation on the exterior surface of the duct and cause moisture penetration througb the thermal insulation vapour scaling may be required and in this case the most important requirement is to limit penetration of the seal
The extent of any vapour sealing of ductwork thermal insulation and the support method to be u ed must be clearly pecitled in advance by the designer
224 For detailed information on the thermal insulation of ductwork reference should be made to BS 5422 1990 which covers the specification for thermal insulation materials on pipes ductwork and equipment (in the temperature range -40degC to +700degC) and BS 5970 1992 which is a Code of Practic for Thermal Insulation of Pipework and Equipment (in the temperature range -lOOdegC to +870degC)
23 FIRE RETARDANT FINISHES ON PLAST C DUCTWORK
231 The designer should note tbat ductwork constructed to DW154 has no teted fire rating or information see Appendix C
24 REINFORCEMENT OF DUCTS WITH GRP LAMINATE
241 General Where ductwork is required in larg T izes than are covered by Tables 2 4 6 amp 7 or with the increased strength sometimes necessary for industrial use external reinforcement is normally pwvided by applicatioD of glass fibreresin laminate
GRP systems will bond satisfactorily with standard UPVC sheet but for pp it is
nece sary to use a specially prepared sheet with a glass fabric backing incorporated dOling manufactllfe
The detailed techniques of fabrication using GRP are outside the scope of this speci lcation but the following notes are offered for guidance of ductwork fabricators
242 Materials
2421 Quality The laminate is made up of polyester resin complying with BS 3532 and glass fibre complying with BS 3496 or BS 3749 The nominal ratio of resin to glass fibre should be 7030 by weight
2422 Minimum properties The laminate shall comply with the followiog mini mum pbysical properties
Tensile strength - 70 MNm Tensile modulus - 7 Gl m Flexural strength - 140 M Im Bond strength (hetween laminate and substrate Not less than 7MNm Bmcol hardnes Not le s than manufacturers specification
The GRP reinforcement educe the expansion of the parent material but the resultant stre ses arc well within rhe strength of the bond However the Iinear thermal expansion curve shown in Figs 34 amp 35 will serve as a guide
Surface resistivity electrkal propcltles and acoustical propertie are similar to the relevanl unreinforced materials The fire retarding properties of GRP may be improved by the use of specialisl laminating resin
2423 Forms available GRP Laminate should be built up from the separate materials ie resin aod glass fibre in the form of chopped
I strand mat or spray ravings
28
DW154 Spcification for Plastics Ductwork
2424 Workshop conditions Polyester resuls are sensItIve to lmperature and the workshop hould b maintained at a temperature of herween 20deg and 25degC HiOh relative humidities and damp onditions should be avoided A good rate of air change must be pro icled pJeferably by m chanical ventilation
2425 Storage of materials Resin and urin o agents shouJd be stored in dark cool condirions away from the working area and in confonnit with statutor requireshyments for tJle middottorage of flarmnable liquid Because of Ule Limited torage lif of the unmixed resin and curing a eot mal lials ~hould be ch eked before use to enLlfe that they are within the manufacturer pe ified sh If life (usually ix month from the dm of manufacrure)
Glass fi re should be stored separately und r clean dry conditions
243 Surface preparafon
2431 UPVC To achieve the specified bond strengtll the urface to which the GRP is applied mut first be thoroughly cleaned and then etched either by mechanical means or by the use of a suitable solvent
2432 pp with glass fabric backing To achieve the specified bond middottrength the fabric backing must be thoroughly impregnated Witll resin
244 Mixing the materials for use The re in 1 a three part mix compri lng base I sin hardener and accelerator The manufactur rs pecj[ied proportions are critical and th llUxmg sequenc pecified must be meticulously foUowed
The resin has a very limited life after mixing and before u e It is dependent on the characteri tics and bulk of th resin the alllount of hardener the degree and method of acceleration and the workshop onditions
245 Methods of application
2451 General The mixed resin may be applied by hand or b pray c1epoition The operation must b completed within the gel time of th y tern and tbe laminat fully cOI1olidated to achi v the phy ieal properties pecified
2452 Hand lay-up The duct surface i coated by hand with resin Llsing a brush and a mar of gla fibp orked in until full consolidation achieved Th proc is repeated untiJ th requird thicknes i obtained
2453 Spray depo Won The duct surface is coated WiUl re in by spray gun with the chopped glass roving added through a separate nozzle The full thickne i obtain d in layer with con olidation of each layer by hand roller
246 Construction
2461 General M ini mum COllst ructional requireshyments are pe itied ill Tabl 10 for rectangular and Table 1J for circular dUClS
2462 Joints and stiffeners Fig 29 30 31 32 amp 33 hoI TOSS
joint and tiffener for reinforced UPVC and PBPP duct
247 Worki g practices The fabrication of ductwork pecifiecl ill thi document i not affected by the addition of GRP
29
DW154 SfJcdJicatiOt for Plastics Ductwork
Table 10 Minimum constructional requirements shy
Longer Side Minimum Sheet Thicknes and
GRP Reinforcement
UPVC FBIPP 1 2 3
mm mm mm Up to 1000 3 plus 3 plus
06 kgm2 06 kgOIl GRP GRP
1001 to 2250 45 plus 3 plus 06 kgm 12 kgm
GRP GRP
2251 to 3000 45 plus 6 plus 12 kgm 12 kgm
GRP GRP
Cross Joints
UPVCFBPP 4
mm socket amp spigot
as Fig 30 or flanged as Fig 29
75 x 9 flange welded on both sides as Fig 29
75 x 9 tlange welded on both sides as Fig 29
rectangular GRP reinforced ducts
SlifTeners Maximum Spacing Between
JointsSljffeners UPVCIFBIPP UPVCFBPP
5 6 mm mm
75 x 9 flat 800 as Fig 31 or
50 x 50 x 5 plastic or MS inverted angle as Fig 32
or tormer as Fig 33
75 x 9 flat 600 as Fig 31 or
50 x 50 x 5 plastic or MS inverted angle as Fig 32
or former as Fig 33
75 x 9 flat 600+shyas Fig 31 or 50 x 50 x 5 plastic
or MS inverted angle as Fig 32
or former as Fig 33
Note 1 On rectangular duct up to 400 mm longer side no stiffeners are required 2 Applies to Tables 10 amp I I For COlJstructional operating temperature limits refer to Part 2 clause 5A 3 Tables 10 amp II apply to all pres ure classes up lo ]500 Pa
Table 11
Diameter
1 III
lJp to 1000
1001 to 1750
1751 to 2500
Minimum Sheet Thickness and
GRP Reinforcement
UPVC FBPP 2 3
mm mm 3 plus 3 plus
06 kgm 06 kgm GRP GRP
45 plus 3 plus 06 kgm2 18 kgm
GRP GRP
6 plus 6 plus 12 kglm2 18 kgm1
GRP GRP
Cross Joints
UPVCFBPP 4 III
socket amp spigot as Fig 30 or flaoged as Fig 29
75 x 9 flange welded on both sides as Fig 29
75 x 9 flange welded 00
both sides as Fi 29
inforced ducts
Maximum Spacing Between
JointsStiffeners UPVCIFBPP
6 mm 2400
800
600
Stiffencrs
UPVCFBPP 5
mm 50 x 9 flat as Fig 31
75 x 9 flat as Fig 31 or former as Fig 33 75 x 9 tlat as Fig 31 or t()rmer as Fi 33
ote On extruded tube tip to 600mm diameter no stiffenergt are required
30
DW154 Specificatioll for Plastics Ductwork
G - Cross joints and tiffeners
Fig 29 Flange Joint Fig32 Stiffener shy inverted angle
M artiPfCuQkbdd erttpObri) Wl111 RP tlddtlt
_- GRPloliu] lh~
Fig 30 Socket and spigot joint Fig33 Stiffener shy use of former
Fig 31 Stiffener Flat
I Pv FlPP ~ ~lmJaDUA1) d
OMrlQ rrnall 1( tQlS
25 STANDARD COMPONENT DRAWINGS AND ABBREVIATIONS
251 The illustrations in this section not only highlight where applicable geometric limjtations for the de ign and manufacture or ductwork components but also recommend
standard drawing representation terminology and abbreviations for both duetwork components and some of the more commonly used ancillaryplant items
252 Designers and surveyors should note that bills of quantities should provide a full description
3)
---
v
DW154 Spcc(fim(ml for Plastics Ductwork
Fig 34 Linear Thermal Expansion
u c 0 N ro 0)
b 0)
S
sect0
5 oS cl) 0)
~
on ~ ltl
c U
-30 -20 -10 0 10 20 30 40 50 60 70 80 90 TEMPRATURE C
~ V
-
~~c_ ~
~V
V ~
-7 ~
-- ~V ----
v
-6
+14
+12
+10
+8
+6
+4
+2
0
-2
--4
ig 35 Typical Design Stress tor UPVC and P
7
6
r shy 5E
-c E----0 4t) VJ 0)
ci5 0Jl 3
~
0)
Cl
2
1
o
UPVC
1
000
1
1
pp
- r-- shy r----- shy - t--shy I
__0
-30 -20 -10 0 10 20 30 40 50 60 70 80 90 TEMPERATURE C C
Note Figso 14 amp 35 shaded area refers to GRP reinforced duct
32
DW154 Speciicfltirm for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - REC ~NGULAR
Splilt~r Posilion W-mm pliucr
A B c 40]--QOO 1 W - -
601-1000 1 W4 Wf2 -
1001-1800 3 WI W3 W2
FIG DRAWING DETAfiS
tU]36 ATI Straight Duct with socket and spigol joint
rn [037 Straight Duct with flanged joints
[I []38 Straight Duct with flanged joints
rkJ Short Radius Bend
39 Applies to any augl and for duct up to 400 n11n wide
Minimum (I1m31 radills = 100 mm
Medium Radius Bend (a illustrated)
[kJ Applies to any angle
40 Long Radiu Bend Similar but radius = W
Throlll radius = W2 Applies to any angle
- Short Radius Bend with plitlers
I -shy -shy u co - t lt Li--_ 41 t 0 ~ I I I
~ I
L 1W
Minimum waal radius = 100 mm Splitters not required in bend angle less than 45deg
42 QJ1 Square Bend with turning vanes ij
3
DW154 SP(L~ficatioll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - RECTANGULAR
FIG DRAWl G DETADS
43
~
I v
L L Radius Tee with internal deflectors
44
~ Radiussed Twin Bend
45
Imiddot
er Swept Branch
46 U-
Sqoare Tee with Turning Vanes
47
~ f
Breeches Piece
48 0 y l Piece
34
DW154 Specificatioll for Plastics Ductwork
STANDARD COMPONENT RAWINGS - ECTANGULAR
55
54
51
50
53
52
49
FIG
~MX
RAWlNG
DmiddotMAX
EfjMAX
Minimum throat rndius = 100 mm
Rectangular shy Round Transformatioll
Eccentric Taper 225deg max in either plane Spliller are required for angles greater than 225deg and hould bi eet the angle between any side and duct centreline
DETATLS
Angled Offset
OUset Taper Splitters are required for angle greater than 22 0
and shoold bi eet the angl between any side and dUCI centrelinc
Mitred Offset
Concentrk Taper 2250 max in ither plane SpUtters are required for angle greater than 225deg and should bisect the angle between any side and duel c ntreline
Radiussed Offset
35
DW154 Splcilcuthm for Plastics Ductwork
STANDARD COMPONENT DRAWINGS ~ RECTANGU AR
Branch ducl DimCllsions widlh (W) (A)
urnl mm up lO 200 75
300 100 400 125 600 150
Ocr 600 200
FIG DRAWlNG DETAILS
56 poundplusmni~~ Rectan~lar - Flat Oval Transformation
57 [ Square Branch
58 er Angled Branch
Branch dUCI Dimensions wfdth (W) (A)
[- mm mm59 3shy Shoe Branch Up (0 200 75
--shy AIshy + 300 100
400 125
450 MAX 600 150
Over 600 200
Branch duct DimensIOn
rP X width (W) A)
60 - 1--shy _
~ mm mm
Bell Mouth Branch pto 200 75 300 100 t 400 125
600 150 Over 600 200
0=0 61 -
~ Bell Mouth
- shy T 4-5deg M x
--I 1-shy
TJ
62 X I ] I
Tele-scopic Joint I Illustrated with flangeL
X63
SBD Single Bladed Damper
36
---
DW154 Spedicatioll for Plastics Ductwork
STANDARD OMPONENT DRAWINGS - RECTANGULAR
DRAWING DETAILSFIG
64 on-Return DamperNRD shyshy
shyXbull
Multi-Leaf Damper Can be piggoted or flanged oppo cd or parallel blade
Alternative controls areshy
q p [gtshy
J HD65 Hand
~MD otori ed
PO Pneumalic
L-lt
l 13G 66 Blast Gate DamperX X
FireSmoke DampersSleeves
211r Ratinggtshy----
L_-
---
----
r----
Ir-- shy
IL- _-l
2hr
With i tallation frame
67 41 r Rating
4hr
Smoke damper SD
Intumc cent Sleeve L-d
37
DW154 Specijicutiolt for Plastics Ductwork
FIG
68
69
70
71
STANDARD COMPONET DRAWINGS shy REC ANGULAR
DRAVING DETAILS
gtshy Access Openings
AP 6 Access Panel - Rerno able
w [ ~ Access Door - Hinged
I ~le Inspection Cover
le -I reg -lt
~X X Flexible Connection
~ Drop Cheeked Radiussed Twin Bend
U Drop Cheek Bend
I
72 Air Flow SymbolX
38
DW154 Specifim[ioll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - ECTANGULAR
FIG DRAWING DETAILS
73
74
75
76
77
Q
Q
rp---t
~
V- I Ir---I
JL --11
THE ABOVE DETAILS TYPICAL PLENUM
Air Terminal Plenums
Plenum with side connection
Plenum with top connection
Cover plate with connection
Special plenum with connection
elescopic conn ction in direction of air flow
39
DW154 SpecijicotiOll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG
78
79
80
81
DRAWING
-23~---pound3-(MALE) (FEMAJE)
-t=j--_j(--d-shy
--L
~ THROAT RADI S= D AS T NDARD
e ~
THROAT Rjf)lU = D A MU)
DETAILS
Straight Duct With male and female connectors
Straight Duct With flange joint and slip joint
Bend MouldedIFormed Applies to any angle ego 30deg45deg60deg90deg Medium radius bend as illustrated Long radius similar but throat radius 0
Segmented Bend 90deg four section minjmum as illustrated
Other Angles 60deg = 3 sections 45deg = 3 sections 30deg = 2 sections
I
i
40 shy
DW154 Speciicafinll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG DRAWING DETAlLS
82 Segmented Twin Bend Radius = D2 max
May also be fabricated from tube
83 Equal Tee MouldedIFormed
84 -~ 1in Bend MouldedIFormed
85 Taper Concentric 1 0 as iUu trated Eccentric 30deg iJJcLuded angle
86 Short Taper
41
DW154 SpcUicatol1 for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG DRAWING DETAILS
87 30 max Offset
Angle Branch
Bran h dUCI Dimcnsions dia (D) lA)
Shoe Branch mm mm 88 Cl
Off rectanguJur Up 10 200 75 lOO 10 400 125
- 00 150 Over 600 200
Bl1IllCh duct DimenlOns din (D) (A
~-$a-Conical Branch mm mm
89 Also acceptable with Up 10 200 r
full conical surface 300 10
400 125
END VrE -shy 600 150 Over 600 200
90
m 75
100 12 150 200
mm Up to 200
_ 300 400
600 Over 600
iUtred Branch
Shoe Branch
J-L----U ~ Bell oulh Branch
ENDV1EW
93
92
91
42
DW154 Specificatiol for Plastics Ductwork
STANDARD OMPONENT DRAWINGS - CIRCULAR
FIG
94
DRAW G
I
~ 30deg 090deg
Breeches Piece
DETAILS
95 amp-----~ Blank End
~-----p Multi-Leaf Damper Can be piggolcd or fianged opposed or parallel blade
Alternative controls areshyri=-+- L-T~
I
---
LT~
I r- -
-+1
J HO Hand96
bMD Molori cd
PD Pneumatic
tl-shy bull
Single Bladed Damper 97 ~ saD
on-Return Damper Vertical application only 98 m~D
43
DW154 Sf1tcificatioll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG
99
100
101
102
DRAWING
$ I-
2hr
1 4hr
SD
~v I I
CO TINENTAL COWL
DETAILS
Iris Damper
Fi reS moke Dam persSleeves
2hr Ratillg
With installation frame
4br Rating
Smoke damper
Intumescent Sleeve
Access Openings
Access panel - removable
Access door shy hinged
fnspection cover
Discharge Continental Cowl
44
DW154 Sp(Cii(ltJll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
DRAWINGltIC DETAns
-
I
I
~
I I I High Velocity Discharge Terminal 103 I
I
I I
J I I 1 ~--
Offset Stack Discbarge Terminal 104 1
~ I e --(-
I
N
I
I
I~
I I Vertical Oischarge with Weather Cowl 105 I
--1--1 I
I
GAPI I
RTl AL DISC) lARGE WITH W ATIIER COWL
45
DW154 SpecUicatoll for Plastics Ductwork
STANDARD COMPONE T DRAWINGS - PLA TEQUIPMENTIMISCELLANEOU
FIG DRAWING DETAILS
106 ~~~ Rectangular Attenuator
107 ~- Circular Attenuator
108
~ Beod Attenuator
109 J ~(f) Heating Coil
110 J ftte Cooling Coil
III Jc[ Electric Heating Coil
112 X F
Humidifier
113 [H XX Axial Fan
114 ~fB1famp Noo-standard Ductwork Cross hntchillg (of any separate type) indicates by reference to a key any non DVil54 ductwork system
115 2llIIIIJIIIIIll Flexible Ductwork
46
DW154 SJeCUicll(iol1 for Plastics Ductwork
TABLE 12 - STANDARD ABBREVIAT ONS
ABBREVIATION FLL
AD Acces Door
AFF Axial Flow Fan
AHU Air Handling nit
All Aluminium
AP Acess Panel
AT Attenuator
AV Air enninal Unit
BE 81ank nd
BQ Blast ate Damper
CC Cooling Coil
CF Centrifugal Fan
CTA Cross alk Attenuator
CVU Constant Volume Unit
DP Drain Point
EEC Electric Heating Coil
El Expansion Joint
FAl Fresh Air Inlet
FA From Above
FB From Belo
fBPP Fabric Backed Polypropyl-ne Sheet
Flexle Flexible Connection
lexfD Flexible Du t
C False Ceiling CO an oil Unit
fD Fire Damper
FFL Finished Floor Level
FJ Flanged Joint
FOAM Rigid Polyurethane Self xtinguishing Foam
FOB Flat on Bottom
FOT Flat on Top
GAM Galvanised after ManufacttrJc
GRP Glass Reinforced Plastic
GSS Galvanised Sheet Steel
HC Heating oil
HD and controlled Damper
HH Hand Hole
HL High Level
HVD High Velocity Discharge
IC Inspection Cover
ID lri Damper
IFS Intumescent Fircleevc
47
DW154 Specification for Plastics Ductwork
TABLE 12 - STANDAR ABBREVIATION CONTINUED
ABBREVIATION
IU
L
tv1D
MS
NRD NTS
OBO
OE
PHD
PD
PP
PP
PRD
PVC
RFC
RSC
R
SBO
SO
S1 TST
SSL
TA
TB
TO TJ
TP
TV
TV
OS
UPVC
S
V
VAV
50 RSA
FULL
Induction Unit
Low Level
Motor controlled Damper
Mjld Steel
on Return Damper
at to cale
Opposed Blade Damper
Open End
Parallel Blade Damper
Pneumatic controlled Damper
Polypropylene
Self xtinguishing Polypropylene
Pressure Relief Damper
Polyvinyl Chloride
Rolled Form Chamlel
Rolled Steel Channel
R fUnit
Singl Blade Damper
Smoke Damper
Slip Joint
Stainl t el
tructural Slab Level
To Ab vc
To Blow
Top Down (In Direction of Flow)
Telescopic Joint
Test Point
TU111iog Vane
Top Up (In Direction of Flo )
Voles Otherwise Stated
Unpl3sticisecl Polyvinyl Chloride
Underside
Ultra Violet Light
Variable Air Volume
Rolled Steel Angle (Vith Size)
48
DW154 SJeriiflllioll for Plastics Ductwork
A2 DUCT PRESSUREAPPE DXA Ductwork con truct d to DWIl54 will bebullbullbullbullbullbullbullbullbullbullbullbullbullbull
Air Leakage From Ductwork To be read in conjunction with DW143 A practical guide to Ductwork Leakage Testing
CAUTION As highlighted ill both this docul1lenr and DW14 I lot ellough emphasis can be placed 01 the fact that except for high pressure class C the much more stringent ductwork constructional standard brolght about b the general acceptance of DW154 have irtlally negated the requirement for leakage-testing It is essential lO realise lhat except where it is mandatory this doclllllelll is nOl an endors ~lIlent of the rourine testing of ducts bllt purely a guide to outline the procedures for cononnity with the air leakage limits ill Table l Where the specified methods of assembly and
A3sealing of dlcls are u ed a vi ual inspection wil ordinarily sl~fll e for ver(iatioll of a well engineered and a ceptahfy airtight COl1strucrioll WHERE NOT MANDATORY DUCT LEAKAGE TESTING IS GENERALLY AN UNJUSTIFIED AND SUBSTANTIAL EXPENSE
A1 INTRODUCTION L akage from ducted air distribution systems is an Lmportant consideration in the design and operation of ventilatjon and air conditioning middotystems A ductviork t)ystem tbat ba limited air leakag within defiucd limits wiH cnsUft
that tile design characteristics of the sytem can be maintained It wilJ also ensure that energy and operatLonal cosb are maintained at optimum levels DucLwork constlucted and Ulstalled in accordance with DW154 should minimise a level of air leakage that it) appropriate to tll operating static air pre sur in tile system
A4However it is recouuised that tbe environment in wtJich middotystems are installed is not always conducive to achieving a predictable level of quality in term of system ajr leakage and it is therefore accepted that designer may sometimes require tlle ystem to be tested in part or in total It should be ecogni ed that the testing of duct systems add a ignificant cost to the installation and incur some extra tjm within the programme (Se 47 and 64 re mandatory te-sting)
manufactured to a structural standard that is compatible with the system operating pressure There are three classes of duct con truction to eorre pond with the three pre ure clas meations Class A Lo pressure ducts suita le for a maximum positive operating pressure of 500 Pascal and a maximum negative pressure of -500 Pascals Class B IVledium pressure ductmiddot suitable for a rnaxilnuJJl positive operafjn o pressure of 1000 Pascals and a maxllnum negative pre sure of -750 Pa cal Class C High pre sure ducts suitable for a maximum po ilive operating pressur of 2000 Pa cals and a maximum negativ pres ur of -750 Paltcals
LEAKAGE FROM DUCTWORK Leakao-e front pia tic air ducts occur at the joint~ and is therefore proportional to the total surface area orthe du twork in th system Tb level of leakage i imilarly related to tIle air pres ure in th du t system and whilst there LS n precis formula for calculating the level of air los it i generally accepted that leakage will increase in proportjon to pressure to rbe pOvver of 065 The effect of air leakage from high pressure velocit ductwork is critical tn terms of system perfomlan dege energy consumption and the risk of high frequency noise as ociated with leakage These problems are le critical with medium pressure 10 ity systems but should be con idered Low pres mevelocity ducts present the lowe~t
ri k in tenn of tbe effect of leakage on the operation of the s stern
SYSTEM LEAKAGE LOSS As there i no di ct relatLonship between th volume of air conv yed and the surface area f the ductwork sy tern required to match the building configuratmn it is difficult to express air leakage a a percentage of total air volume Similarly the operating pressure will vary throughollt lh 3 system and a leakage is related to pre me the calculations ar comple However it is generally ac epted tbat in typical good quaJjty systems the leakage from
49
DW154 Specificatioll for Plastics Ductwork
each class of duct llnd r operating condition will be io the region of CIa S A low pressure 6 Clas B medium pres un 3 Clas C high pressure 2
A5 SPECIFYING AIR LEAKAGE TESTING Re peeting both the co -t and programme implications a sociated with te ling du 1 for leakage the designer may for example indicate that a particular system is te ted as follow
a) High pressure ducts - all tested b) Medium pr ssure duets - 10 of the
ductwork shall be s eet d at random and tested
c) Low pre sure - unte ed In any case where a random te t i elected for medium pre sure ductmiddot the followin c1au~e is suggested for inclusion by the de ign r
The designer hall elect at random a maxirnwlI of 10 of the dUCl system to bt tested for air leakage The duct hall be tested af the pressure recommended in Table J3 for the assifi atiol for the ectiol1 of the ductwork that is to be tested The tests shall be carried Ollt as the work proceeds and prior to the application of thermal insulation In the event of test failure of the randomlY selected section the designer shall have The right to select two La1her e tiolls at random for resting Where succes ive failures are identified there shall be a Tight to require rhl COl11raCWr 10 apply remedial attention to the complete ductwork system Th contractor shall provide documented eviden e of the calculalions used to arrive (1
the allowable 10 I for the section to be tested and the client or his agent shall willess and sign the results of the test
able 13 Air leakage rates
Maximum leakage of duct work Static
prcssUft Low-pressure edium-prc-sure I Iigh-prebull me diJfercntial Class A Class B Class C
1 2 J 4 Pa Litres per second per quare metre of surface area 100 054 018 ZOO 084 028 300 110 037 400 132 044 500 153 051 600 058 019 700 064 021 800 069 023 900 075 025
1000 080 027 1100 1200 1300 1400 1500
029 030 032 033 035
1600 1700 1800 1900 2000
036 038 039 040 042
Note Recommend d mean test presures are highlighted iD bold type with the actual selection being left to tll test operator
50
DW154 Sfeeiieaioll for Plastics Ductwork
A9
A10
and air leakage classification for the y em under test
DESIGNERS CALCULATIONS The designer can middotaJculate with reasonable accuracy the predicted total loss from a ystem by
a) Calculating the operatin presure in each ection of the sy tern
b) Calculating the surface area of the ductwork in each correspondin pre lire s ction
c) Calulating the allowabl~ los at the operating pressure for each ection of the system (see table 13 for allowable leakage figures)
VARIABLE PRESSUR S IN SYSTEMS De igner can achieve significant co t saving by matchina operating pressures throughout the system to constmctional standard and appropriate air leakage testing eO the practice of specifying construction tandards for whole duct sy tems based on fan discharge pre sure may incur unnece sary costs on a project For example ome large sy terns ould well be classiC ed for I akage limits as follows
Plant room risers CJas C Main floor distriblltJou CIa B Low pre sure outlets Cla A
A6 SPECIAL CASES There may be ~itLlations on a project where circumstance dictate thal pecial consideration be given to containing air loss s eg a long mn of duclwork may incur a di -proportjonate level of air 10 s In ca es such as thi example the designer can specify an improved tandard of airtighmess ie 80 of alJo~able 10 s for la B Ju ts The designer sbould not specif a CIa C t sI at CIa s C pressure for a CIa s B ducl
A7 SUGG S ED RANGE OF TES ING
A8 TESTING OF PLANT ITEMS Items of inline pJant (eg Fig 106 to 115) will not normaUy be included in an air I akage test The dllctwork contractor may indud such itelllS in tbe te t jf rh quipm ot has a certificate of COnfOlnlity for Ihe pres ure clas
bull High pressure duct bull Medium pre sure ducts bull Low pre sur ducts bull Exposed extract syst ID bull Ceiling void extract
systems bull Secondary ducts from
VAV or fan coil units bull Flexjble duct bull Final connections and
branches to grille and diffusers
100 test See A5 Untested UDt sted
Untested
Untested Untested
Untested
SI
i
DW154 SJecijicafion for Plastics Ductwork
ig 116 Permitted leakage at various pressures
Leakage in litres per second per square metre duct surface area
Vgt
o ltgt 0 ltgt N
ltgt Cgt
0 0 cc
0 0
~
g =
g ~
c 0
J
ltgt 0 I
~ ] tn
ltgt ltgt
In ol
~ 0 ~ 8 ~
~
c ltgt ltgt
~ CJ
~ ~ ~ ~ 8
0shyij
~ ~ ~ t
ltgt ltgt 00
l
~
~ Q
c C
~ rshy
e ltgt
I 1
I Cgt ltgtv
c Co ~
~~ ~ 10
I
0 Cgt
fJshyq 410 ) 1 ltgt
ltgt N
~ shy ltgt ltgt
~ I 1
c
52
DW154 Specificatio for Plastics Ductwork
Example of a completed test sheet Test No
General
Name of job N~ jC43Pt(r2lef Building Repound ~(~~0
Part 1 - Physical details
a Section of duct work to be tested ~(diffPIfff~el1f3rd Floor
b Drawing Number g91~~ c ssure aSSJ L atlOn V~Jl~IRfYgtg~~lPre Cl T Class C
d Test static pressure -(9 raErq~ ~~~~-~~J~~~ ~~ ~~~~ll
Leakaoe factor 9~-tre3$ecMz I OM REFTOTABLE 13)e b bullbullbullbullbullbullbull
f Surface area of duct under test Q~tJJItetre$ CPROMCALCU TIO BELOW)bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull ampampamp bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull
g ]Vlaxi mum permitted leakage -~ (~i~~0 ~~r~~ ~~~l-~-11~ ~~~Q
Part 2 - Test particulars
a Duct static pressure reading 9QFt~q~ ~ middot~~~1 ~~
b Manufacturer and type of liow measuring d vice (-~~~cJ~Y-9Q7EYg c Range of measurement of now measuring device QtP)OQ~(e~~~0I~~~~1~I~ ~~~~~~W~
d Reading of flm measurin o device pmiddot IFROM RIO)ftscag ~
I (DERlVED [ROM CHART SUPPUED WITH RIG US 0 ud)1e Interpreted air flow leakage rate ~(~~~f~~~ (~l~~~~~~~~~~~~~~~~~I
f Duration ~~~~~norn~allY l~ lnil1Ut~~d~~~ it1~ W~ Date of test ~(lITled ut by Wltll s ed by ~ ~
(~lJ MIJLrr) (Si~rrfltJUYJ
Printed Name 1~g0f~ Printed Name ~~Y~9~ and Company 7jl~~~~~( UJd CompanY AB COII$Itallt8
Width and depth or diameter
Periphery ength Area
millimetreS millimetres metre qL1are metre
800 x 750 3100 1755 5440
600 x 650 2500 557 1193
300 x 300 1200 120 144
305 din 958 700 670
250 dia 785 450 353
TOTAL 8000
53
DW154 Specijilarion for Plastics Ductwork
pA XB
Guida ce No es For he ransport Handling and
Storage of uctwork
avoid damage to adjacent duct panels In somc ca es particularly on con acts calling f r repetitive sizes the use of timber jigs and spacers may be justified Where reduced bulk and greater protection are major factor such as consignments for export transporting ductwork in L shape sections may justify the increa ed ite as embly co ts
It is recommended that before a contract is finalised that consideration is given to the subject of site acces material handling and storage as tbcy havgt a strong influence on the cost efficiency of the overall activity of ductwOlk installation
B3 Handling To minilnise th risk of damage duct sections should be clearly identified and deliveries to site should be closely linked to the installation programme so as to avoid accumulation of
B1 Storage and Handling of Ra Material Material should be stored in suitably designed racking out of direct unJight Where possible the e racks should be metal to earth Edges of cut she t may be harp and protective gloves are advised Wearing teel toe-capped boots is recommended Most pIa tic sheet is manufactured with smootb mfaces andor is suppLied with protective coating Care must be taken to prevent accidental lippag of stacked materials Beiuoshy good electrical insulators the movement of stock unless earthed will allow the build up of stati All stock shapes are chemically stable at normal temperature Whil t some raw materials used in their manufacture may themselves pre ent a toxic hazard once incorporated into the lOck bape they no long r constitute such a hazard and no dermatitic bazard are known nor are any
unfiJied ductwork and minimise double handling It is important to recognise that ductwork panels joint and corners arc susceptible to damage and care must be taken wheu band ling such material through a site During handling individual item of duct work may be liable to light cross sectional deformation until thev become an integral pan of a completed ductwork system Whilst this may temporarily detract from its intended appearance thi deformation will not have any detrimental effect on the functionality of the finally a semblecl system Installation of duct work and asociated plant items ill illevitably involve manual handUng The responsibi Iiry of employers and employees to a ses the risk of personal injury during mallual handling operations is et out in the HS E publication L23 Guidance on Manual Handling Regulations 1992
environmental problems expected 84 Site storage
B2 fransport Large capacity vehicles with high-sided open or closed-top bodies are tlle mo t suitable for the transport of dllctwork Careful consideration should be given to the
Adequate floor space IDust be provided within tbe building for the site storage of ductvork Such storage shalt make due allowance for thc stOf(ne of ductwork in stacks such that access ~ egt
between them is of sufficient width to pennil the removal of item without interference to
unloading of transport on sit a not all siJes b n fit from the material handlino- and access facilities that exi [ in a manufacturing workshop such as crane- fork-lifts or loading bay Site handJiog facilities along with
adjoining sta ks Ductvork components should be positioned so a to avoid crushing Ductwork of small panel size may be stored horizontally however care should be exercised to ensure that tack sizes are limited 10 within
ehicular acce s restrictions may itilluence the type and ize of transport to be uWised
engtlls of ductwork should be positioned 0
the tmctural strength of the duct sections to prevent distortion of the lower sections within the stack
as to avoid crushing Lengths Witll projections such as branches and bends i1anges girths damper quadrauL should be loaded so as to
54
DW154 S1tciic(ltioll for Plastics Ductwork
85 Internal cleanliness of new ductwork The site storage of ductwork introduces the important cODsideration of maintaining the internal cleanliness of the ductwork R feren e should be made to HVCA documentshybull DWffM2 Guide to Good Practice - internal
Cleanliness of New Ductwork Installations If the above conditioDs can not be satisfied consideration should be given by tJle designer to amending the specification to include for Po t Installation Cleaning as covered by tJ1C HVCA documentshybull TRJ17 Guide to Good Practic - Cleanliness
of Ventilation Systems
APPE DIXC
Fi e Retardant inishes C1 Improvement in the fire retardancy of plastic
ducts can be achieved to varying degrees and is wholly dependent llPOll the surface coating laminating resin selected and construction specification adopted In some instances smoke emission is coILSidered equaUy with other speci fication requirernen ts of the materials resistance to ignition and bumjng It is therefore important for design rs to establ ish the clients and officers detailed requirements and not rely on a tbird party interpretation of fire resisting or fire retardant Where possible the specification should refer dir etly to compliance with a British or European Standard identifying the specific sections applicable There are various types of resin and mat rcLnforcements that can achieve a Class 1 surface spread of flame ratin o when tested according to BS476 Part 7 (1987) This test puts materials illto Class I - 4 in descending order of perfoDllance according to the rat and extent of flame spread over their surfac under standard beating conditions Materials should also be tested for flre propagarion to BS476 Part 6 (1989) Tbi tesr measures the amount and rate of heat evolved by the material when subjected to standard heating
conditions Test results are given as an index of Perfonnance (i) whicb is based on three sub indices (iJ (i1) (h) The higher the value of the Index of Performance (i) the greater is the material s contribution to fire growth The higher the value of the sub-index 0) rhe greater the ease of ignition aod flame spread The highest product performance classification as defined in Approved Document B of the Building Regulations is Class O This is acLlieved if a material surface of a composite ploduct i~ either a) composed throughout of materials of
limited combustibility or b) a Class I material which has a tlre
propagation index (i) of not more than 12 and sub-index (i l ) of nor more than 6
01 J Class 0 is not a cla$sif1cation identified in any British Standard test
There are resin system reported to be classified to Class O when tested to BS476 Pcl1S 6 and 7 however designers need to ensure that such sysrems can be applied to their proposed design In propriety resinmat system available the fabrication techniques and COITect application are critical to the integrity of the reinforcing and clas ificatiol1 For example in some systems the u e of a non-fire retardant gelcont on a fire retardant substrate would reduce the classification For further information see HVCA publication DW144 Appendix D
55
DW154 SplCijiClIliol1 for Plastics Ductwork
x Guidance otes For nspectmiddoton Servicing a d
Clean-ng Access Openings
D1 GE ERAL This appendix highlight in ummary fOI111
the acce considerations that hould be made by the design r iD terms of inspection servicing and cleaning Having considered the seop and the design of the dUCI work system relative to the guidelines outlined below the designer should clearly indicate which levels of acces should be incorporated into the manufacture of a new duct work system (See Table 14 and Note I b low it
D2 DESIGN CONSIDERATIONS
D21 In ptction and servicing requireshyments are set out in Section 15 of Lhis specification
D22 Cleaning requirements are set out in the HVCA pubUcation TRl7 Guide to Good Practice Clean Lines of Ventilation Systems and the guide tates The precise location ize and
type of access would be dependent on the type of ductwork cleaning inspection and te ting metbods to b adopted Care protection and standards of cleanliness prior LO cOlllmisionin o
are set out in th AV A publication DWITM2 Guide to Good Practice Internal Cleanliness of New Ductwork Installations and th guide state Wh re specific limits of cleanliness are required ductwork sball be cleaned after installation by a spcialist cleaning contractor It will b in the interests of tht desioner botb financially and practically to cunsider employing a specialist c1eauing contractor at tbe
outset of a contract to internally clean newly installed ductwork prior to bandover This approach would reali e the following benefit shyi) Tb actual numb r of cleaning
access panels could be detennined to suit the method of cleaning to be adopted (This may be 1 s than the maximum requiremen listed under Lev 13 of Table 14)
ii) Clear directions could b given to the ductwork contractor as to tJle size and location of cleaning access panels that are required to be fitted during the mauushyfaclunng pro s
iii) The specialist cleaning operation prior to commi ioning vould enable the cleaning contractor to verify the practical acee requirement for the future cleaning operation associated -vitb a regular maintenance programme
iv) A specialist cleaning operation prior to commissioning would allow the designer to omit from the speeilicatiolJ the DWrrM2 requirem nt for factory sealing protection wipe downs and capping-off
v) Specialist Ieall ill 0 to the measurable standard defin d in TR17 will allow an objective definition of cleanline to be achieved
Car ful consideration must be gIven by the designer to the practl aJ problems associated witb the manufacture and fitting of suitably si Led access panel on small cross section duct and on the circular faces of rouod and flat oval ducts in particular
D23 Special con ideration must be given by the de igner to the practical problems associated with gaining personnel access to heavily congested ceiling areas and multi-la red du twork systems This approach would avoid
56
DW154 Spfciication for Plastics Ductwork
the possibility of access panels being D3 ACCESS 0 IN-LINE EQUIPMENT incorporated into a ductwork system at the This appendix unly covers acc il1spection manufacturing stage that were later found in through the ductwork body adjacent to an item practice to be inaccessible for either ervicing of in-line equipment and not openings in the or cleaning activities equipment itself
able 14 Acce requirements for inspection servicing and cleaning
HVCA PUBLICATIO REFE NeE (uidtgt 10 Gund Prartict
Adjace t OW144 Cleanliness orVcnlillltio S~lcr~ fRjJ7
in-line LeyeJ 1 Level 2 Level 3 ite sequipment pcdionSen lcin~ Section d C1eaniJl( SUn(O)lnspc lion Palle ltk~m_n
2011 (minimum OiL Jubje-ct to duct ~zel (ft~ -Panels
Control Da pcrs One (inspection) 203 One 300 mm x 200 mm Both sid Fire Dampers One (sCTjdJl~) 20211 One 300 0101 x 200 mm One side HeatingCooling Coils One (inspedion) 20213 One 300 mm x 200 mm (lIpstream) Both sides Attenuators (rectangular) None required One 300 mm x 200 mm (downstream) Both sides Attenuators (circular) one retluired One 300 mm x 200 mm (downstream) One side Filter Sections One (inspection) 20212 one required Uoth sides Air Turn Vanes None requjred None required Both sides Changes of Direction None required one required One side In-Duct FansDevices One (inspection) 20213 None required Both sides l
1 In the absence of any indication by the designer only Level ) access will be jncorporated into a new ductwork system
2 Tbe panel izes associated with Lev lis I and 3 acee s ar e middottablished by reference to Section 20 of DW144 and Section 2 ofTRll7 respectively
57
DW154 Speclfifatio for Plastics Ductwork
pA XE
B-bliography Included in this Bibliography are technical pUblications which may be of interest (0 ductwork designers fabricators and erectors and to tho e in the heating ventilatlng air conditioning industries generally nquiric should be made of the relevant organisation at the address quoted Since its publication other addresse contained within 0V154 mav have changed and some pubJicalions may have been superseded
HEATING AND VENTILATING CONTRACTORS ASSOCIATION
4 Palace Court London W2 4JG Telephone 020-7229 2488 Fax 020-7727 9268
Orders fo FlY A Publications Old Matlsion House Eamont Bridge Penrith Cumbria CA 10 2BX (Telephone 01768 864771 Fax 01768 86718) Email hvcapoblicationshvwelfarecouk DWn 44 pe ilicatiun for sheet mctal duclwork (Iow- mediulllshy
and high-pressure) 1998) DWIl4 A practical guide to dUGI ork I akage te ting
(revised 2000) DWII54 Specification for plastic~ duct rk DW171 Guide to good Practice for kitchen venlibtion system DW191 Guide to good pracuce glass fibre ductwoJk DwrrMI Acceptance cheme for new products - Redangolar cro
joint classification Guide to good pra tice - Internal cleanliness of new ductwork installations Guide to good practice for the design for the Installation of lire and smoke uampers
J 1Other puhlications
HampV safely guide 5th edition JS2 Tool box talks JS5 Weldlng Safety booklet JSI9 afety facts bo klet Fact sheets 1-24 2nd edition JS2J COSHH manual volume 1 Advice on compliance with the
regulations 1521A CO I-rH manual volume 2 Asses mcnt h ets JS23 Ri k management manual TR3 BrazinltT and bronze welding of copper pipework cUld sheet
(I 976) TR5 Welding of carbon steel pipework (1980)
TR6 Guide to Good Practice for Site Pre sure Testing of Pipework (19 0) Guide to good practice cleanliness of ventilation Ylem
CHARTERED IN TITUTlO OF BUILDING SERVICES E G EERS Delta House 222 Balham High Road London SW12 9BS rTelephone 020-8675 5211 Fax 020-8675 5449) CIBSE Guide Volume A Design Data Volume B In tallatiol1 and quipment Data Volume C Reference Data
CommlssioniJIg Codes These Codes eover the preliminary checkS eUing to work and regulation of vanous catcgories 0 plan The Codes give a guide to design implications Series A Air Distnbution Systems Series B Boiler Plant
ri s C Automatic Conlrol ystems Cr1es R Refrigerating Sy terns
Sene iN Water Distribution Systems
Technkal Memonllda TM 4 Design Notes for the Middle East TM bull Design otes for Ductwork TM 13 Minimi iog lhc Risk of egiounaires Disease
Research Reports RROI95 Ventilation system hygiene - A review of published
infomlatioo on lhe occurrence and ffects of Olltamination Rl~02J95 Air-to-air heal rec v ry RR0395 rnfluen e of HV C on smoke detectors
ATlONAL ENI [ERING SPECIFICATION LfMITED Southgatc hamber 3739 Southgate Street Winchester S023 9EH (Telephone 01962 842058 Fax 01962 R(8982) BUfLDING S RVICES RESEARCH AND [ ORMATION ASSOCIATIO Old Bracknell Lane West Bracknell Berkshire RG 12 4AH (Telephone Brackl1eU (01344) 426511 Fax 01344 487 -7 )
Application Guides AGln4 De tglJing Vana~le Volume middotylans for KOOnl
iir Movement AG1I91 Commissioning of V Sylcms in Buildings 11 6194 Fire Dampers
B) 94 cntiJalion or KitcneTls
AG389 The Commls ionin of Air Systems In Buildmgs AH2192 Commissioning of Bern - A ~ode of Practice TN2417 I Fire Dampec il) Ventilating Ducl
BEATING VENTILATING A AIR CONDITION G MA UFACTURERS ASSOCIATIO (HEVAC) HEVAC Henley Road Medmenham Marlow Buck SU 2ER (Telephone 01491 578674 ox 01491 575024 Emoimiddot infofetacouk)
Publicatjons Air Diffusion Guide Guide to Air Handling Unit Leakage Testing Guide to Good Practice Air Handling Unit Real Room Acoustic ~ st Procedure Specification for the ertiiicatioll ofAir Filters Method of Test for Water Rejection PerfOnTlatce of Louvrcs Subjected 1(1
Simulated Rainfall Test Procedure for Acoustic Loo cs Specification 10 Floor GrilJes - Types Performan e and Method ofTest Specification for the Determination of the Collection Efficiency of SilJ1d
Trap Louvre Domestic Mechwlical Vclltllalion Systems with Heal Recovery Fan Application Guid
~an and Ouctwork Installation Guide Guide to Fan Noise and Vibration
pecification of Requirements for JallJral Smoke and Heal Exhausl Ventilators
pecification for Powered Smoke and Heat Exhaust Ventilators
Specification of Requirements for Smoke Curtains Design Gujue of Smoke Ventilation for Single Storey Lodustrilll Building~
Including those with Mezzanine Floor and IIi Racked Storage Warehou es - Issue 3
Guidance for the Design of Smoke entilation YSlem for Covered and Undergrollnd Car Parks - lssue 1
Application of SOloke Control Equipment and Syst m Guid to Good Practice - Isue J
58
DW154 Sp(C~tiifitiol for Plastics Ductwork
BRITISH STANDARDS INSTIT TION Sales Department 101 P ntooviLle Road London NI 9ND (felephone 020-78 1 78801)
CP 413 1973 Ducts for building ervices
SS 476 Fire tes on building matenals and lruc(ure
Part 4 19 4 Non-combustibility lest or materials
Part 6 I Fire propagation lest for materials
Part 7 1993 Surface spread of tlarnJ tesls for materia
Part 20 1987 Fir resistance of elements of construction
Part 21 1987 Fire r sistlUlce of loadbeanng elements of construction
Part 22 1987 Fhe istallceofllon-loadbearing elemcllts ofconsttuclion Part 23 1987 Contribution of componcnts to the fire resistance 0 a
structure
Part 24t987 Fire resi lance of wl1lilation ductl
SS 5588 nan 919 0 Fire Precautions III thc desIgn and OOSlnJ lion of buildings
S 729 1971 Hot dip galvanized oatiugs (or irOIl aod stcel articles
BS 1449 Steel plate sheet and Irip
Pan 11991 Carbon steel plate heel and strip Part 2 1983 Stainless steel plate sheer and strip
and
B middotENJOI49-2 996 BSEN 10149- 1991)
BSEN 10131 1992
BSEN22063 Sprayed metal coarings 1994 Protection of iron and steel by aluminium and zinc against
atmospheric cOlosion Irotectiotl of iron and ste I against corro ion and oxishydation at elevared temperatures
BS 353 1981 Glossary of lerms relnting to thermal insulation
BS ISO 1479 Self-tapplngscrewsandmetallicdri c crew
B -lSO 7049
1994
B 4800 1989 Painl colour for building purposes B 4848 l0 rolled structural steel sections
Part4 1972 Equal and unequal angles BS 5422 1990 Specification for the use of therm illuating matcriulS
SS 5720 1979 ode of practice for mechanical veutilating and air C 11shy
dirionin bull in building
l3S PR 12814-1 Bend resting for plasric welds
SS PR 12814-2 Tensile testing for plastic welds
SS PR 13067 Appro altesting for plastic welds
BS PR EN I 100-] Vi ual in pection ofplaslic welds
SHEET METAL AND AIR CONDITIONING CONTR-CTORS NATIONAL ASSOCIATION INC (SMACNA) Headquarters 420 I Lafayeue Center Drive Chanlilly Virginia 2051-1209
Mailing Address pa Box 221230 Cbantilly Virginilt120 153-1230
Telephone (703) 803-2980 Fax (703) 803-3732
Accepted IJJdustry Pl3Gtice for Industrial Duct Constnlelion 197 ) i-rchitecmral Sheet kwl Manual ([993)
Comractors Guide lor Modification 10 ooslruerion Colllraets 1993 Ducted Eleclric Heat Guide for ir Handling Ssrerns (1994)
En~rgy ollservatioD Guidelines (1984) Energy Recovery Equipment yslClllS (199l
Fibrou GIns Duct onS1ntClion Standards (1992)
Fire Smoke amp Radiation Damper In tall Guide for HVA Syst ms (1992) Guide t leel Stack 1(95)
HVA Air Duct Leakage Test Manual (19 ) HVA COlllmissioning lvlanual (1994)
H A Duct Construction Standards-Metal amp Flexible (1995) Addendum 01 (Nov 1997)
HVA Duct Systems Inspection Guide (1989)
HVA ySlems-Application (1986) nVAC ByternS-DLlct D ign (1990)
HVi Systems-Testing Adjusting amp Balancing (1993)
indoor Air Quality Manual (1993) tcheu quipment Fabrication Guidelmes (1990)
Managers Guide for elding (1993)
Rectangular Industrial Duct Cons1TUction Standards (19 0) Round Industrial Duct oustmction Standards (1977)
Sei mic Restraint Manual (1991) (wl Appendix E 1993) SMACNA Ma le Index ()fTechnical Publications (1995) Tbennoplnstic Duct CPY ) Construction Manual 1994)
DEPARTME OF THE ENVIRO MENT (Publications Centre) H Stationery Oflice 5 Nine Elms Lane London SWS 5DR
MampEJ 011972 Electrical in tallat1011 in buildings ( ew Editiou)
IampE 0319 Healing hot and cold wat r steam and gas losla1lations for buildings
M amp - No4 1970 Central heating and hot and cold ~ ateT in tallations for
dwelling
M amp ENo100 1971 Mechanical ventilation for building~
ASSOCIATION FOR SPECIALIST FIRE PROTECTlO As ociation House 235 Ash Road AJdershot Hampshire GUl2 4DD
Telephone OJ25221322 Fax 0 J252 333901
lublicalioos Fire Ratcd and moke Outlet Ducrwork An Industry Guide t Design and InSlalla lioll
HEALTH AND SAFETY EXEC TIVE Rose Court 2 Southwark Bridge London SEl 9HS Telephone 020-7717 6000
TWJ THE WELD G TlTUTE Abington Hall Abington Cambridge CB16AL Telepbone 0 J223 89162
Publication DatJ Oil w~ldll1g of lhermopla lics
59
DW154 wciiwlioll for Plastics Ductwork
A -=--DIX
Factors
Specific gravity shy pp = 091 approx UPVC = 14 approx
Some miscellaneous conversion factors
To convert
Length Inches to millimetres Feet to metres
Multiply by
2540 03048
To convert
Millimetres to inches Metres to feet
vIultiply by
003937 3281
Area Square inches to square millimetres 6452 Square millimetres to square inches 000155 Square feet to square metres 00929 Square metres to square feet 10764
Volume Cubic feet to cubic metres Cubic feet to litres Gallons (UK) to litres
002832 2831 4546
Cubic metres to cubic feet Litres to cubic feet Litres to gallons (UK)
35315 00353
022
Mass Ounces to grams Pounds to kiJograms Tons to tonnes
2835 04536
1016
Grams to ounces Kilograms to pounds Tonnes to tons
003527 2205
09842
Volume flow Cubic feet per minute to cubic Cubic metres per second to cubic
metres per second 0000472 feet per minute 2119 Cubic feet per mIDute to litres Litres per second to cubic feet
per second 04719 per minute 2119
Motion Feet per minute to metres per second 000508 Metres per second to feet per minute 197
Pressure Inches water gauge to millibars 2491 Inches wateJ- gauge to pascals (Pa) 2491 I Pa = I ewton per square metre = 10-2 millibars
60
Heating and Ventilating Contractors Association Esca House 34 Palace Court London W2 4JG
Tel 020 7313 4900
e-mail contact Itvcaorguk web site wwwhvcaorguk
Fax 020 7727 9268
DW154 SPCCijicllfiull for Plastics Ductwork
practice to provide common terms ofPA T4 reference for designers quantiry urveyor and
Circular Ducts
12 CIRCULAR DUCT SIZES Th duct sizes [n Table 4 have been selected from the ISO and C standard ranges as the 132 preferreod sizes
Table 4 Circular ducts shystandard extruded tube sizes
133 Extruded tube
ISO Standard Sizes (Nominal Diameter) 11
Wan Wall Thickness Thickness
mm mm mm mm 110 500 4022
I25160 600 50 I25200 630 60
225 25 700 60 13425250 800 63
280 900 70 315
23 23 80
355 1000
25 1250 104 400 32 1400 108 450 35
Note The above sizes are subject to normal manufactl1ring tolerances Other size may be available in varying wall Lhicknesses and subject to test and operational pressure
13 CONSTRue ION
13 General Tllis specification covers duct sizes up to a maximum diameter of 1500 mm The minimum constructional requirements for UPVC amp PPPPS un-reinforced ducts sball be as Tables 6 amp 7
ductwork contractors and tho e using computers in ductwork design and fabrication The requirements for circular duct fittings apply throughout the size ranges covered in this specification
Sheet jointing seams Seams shall be joined either by continuous fLiJer rod hot air welding or by fu ion welding Other forms of jointing are not acceptable
Socket and Sl)igot joints Socket and spigot joints shall be formed by purpose made double socket pieces 100 mm long and of the same thickness material as tJJe duct welded into position on each tandard length of duct forming 50 mm deep sockets prepared and ready for final jointing on ite with PVC adhesive andor fill r rod of the same formulation used for fabrication
Flanged joints
1341 Flanges abricated flanges shall be conshy
structed using minimum of 9 mm thick by 50 mm wide material of matching formulation depending on duct size as shown in Tables 6 amp 7 The flange shall be mounted true and square to the duct surfaces and welded OD both sides a 103 and Fig 12
1342 Drilliogs Drilling ball be placed to permit clearance to the external casing and any reinforcement of the ductwork
1343 Fastenings For normal application bright zinc plated bolts nuts and washers hall
16
For srualler diameters preformed fittings are available otberwise fitting are fabricated from segments of duct or sheet welded together
The terminology and description of circular duct tiltings as set Ollt in Section 25 are recommended for adoption as standard
be used in sizes and pitCh centres shown in Table S Wh re special conditions prevail consideration of other material finishes such as stain le steel bolt nuts and wasbers shall be u ed In all ca cs gasket materials as Seciion 825 shall be USed
DW154 Speciliwriml for Plastics Ductwork
135 Stiffeners
1351 External stiffeners Shall be fitted as specified in Tables 67amp 1 I and Fig 13
1352 Internal stiffeners The use of internal stiffening or bracing hall be acceptable if deemed neces ary and appn ved by the designer
f 36 Expansion joints Where the corrfiguration of the ductwork does not provide for movement due to temperature
Cross joints - circular ducts
change or where such movement is restricted by branches or attachments expansion joints should be fitted (See Section 18 Flexible Expansion joint connections)
It is the responsibiLity of the designer to identify the position of any necessary expansion joints based upon design parameters for the individual systems (See Figs 23 24 2534 amp 35)
Design Note Examples of expansion joints shown are not suitable for movement exceeding 30 mm
Fig 10 Socket and spigot joint (UPVC and PP)
ConLinuous weld joim on ite Ontinuous weld
crlr~l
Fig 12 Flange joint (UPVC and PP)
Continllous wcld
boil
Continuous weld or Solvelll cement
Solvelll ccmcnl joim on sile
Fig 11 Socket and spigot joint (UPVC only)
Stiffeners - circular ducts Table 5 Fastening centres shycircular duct flange jointsFig13 Flat
flat conljnlJou~ly welded Diameter Pitch Bolt Size
max
1 2 J 11
1 shy -~
mm mm mm Up to 600 100 8 with washers
601middot1000 100 10 with washers - ---I
1001middot1500 100 10 with oversized washers
1
Minimum offourfixings
17
DW154 Specifiiutiofl for Plastics Ductwork
Table 6 constructional quiremen s - circular unshy inforced U VC
Diameter Minimum Joints Stiffeners Maximum spa ~in r
Sheet between Thickness Jointsl tiffcners
1000 Pa 1500 Pa
1 2 3 4 5 6 UD mm mm mm mm
UO to 600 3 socket amp spigot as Figs 10 11
or fla ged Fig 12
601 to 1000 45 socket amp spigot 50 x 9 flat 2400 2400 as Figs 10 11 welded bo sides
or Oanged as Fig 13 as Fig 12
1001 to 1500 6 Hanged 75 x 9 flat 1200 1200 as Fig 2 welded both ides
as Fig 13
Applies 10 Tables 6 alld 7
Note 1 For constructional operating temperature limit refer to Part 2 luu 54 2 To allow for conicleration or extruded se lions or fabricated component the materia] tllicknes i hawn a nominal
Table 7 Minimu onstrucfional requirements shy circular un-reinforced PPS and
Diameter Minimum Joints Stiffcners Maximum pacio Sheet between
Thickness Join sStiffener 1000 Pa 150n Pa
I 2 3 4 6 mm m m mm
110 to 500 3 socket amp spigot as Fig 10 or flaoged as Fig 12
501 to 750 45 ocket amp spi~ot
as Fi 10 or Uanged as Fig 12
751 to 1000 6 tlanged 50 x 9 Oat UOO 12 0 as Fig 12 welded nth sides
as Fig 13 1 1 to 1250 6 flanged 75 x 9 flat 800shy 800
as Fig 12 welded both sides as Fig 13
1251to~ flangcd 75 x 9 Oat 600 600 as Fig 12 welded both sides
as Fig 13
18
DW154 Sped(icalirm for Plastics Ductwork
PARTS
Hangers an Suppo ts
14 GENERA
141 Supports are an e sentiaJ part of me ductwork system and their supply and in tallation are normally the responsibility of the ductwork contractor The principl s are a I-rvCA publication DWIl44 Part 6 Section 19 and should be read in conjunction with this document
Design Note Designers may pecify specific requirements wbich will supersede guidance given in DW144
142 Rectangular ducts abl 8 give the- minimum requirements for
hanger and supports for un-reinforced ductwork
143 Circular ducts Table 9 gives the minimum requirements for hangers and upports for uD-reinforced ductwork
144 Vertical d cts The design of supports for vertical duct is dictated by site condition and where practical duc hould be upported at 4000 mm interval or where tbey pa s through a floor (but n ver exceeding 4500 mm) see Figs 17 amp J8
145 External ducts Where ducts are external to buildings and may be ubject to wind loading support should be plac d so as to restrain ide tl1ruSt and should allow axial movement as neces ary It is the respon ibility of me de igner to calculate the effect of the particular prevailing condition and to define any special upport requirement
146 Expansion joints Support shall be designed to permit axial movement only and shall e provided on eitl1er ide of expansion joint
I 1shy
I~
mm -Jp to 400
401 to 600 601 to 1000
Table B Hangers and Supports - rectangular horizontal ducts
Hanger Bearer Drop Roll Formed Rod
Long r Side
Cbannel ~-shy ~
---shy
Maximum ~pacing
4 52 3 _ -c Fig 15 - Figs 14 15 16 amp 2J
shy
mmm mmmm 240025 x 25 x 16 40 x 20 x 15 8 240040x20x15 40x 20 x 15 10 240040 x 20 x 1~510 40 x 20 x 15
shy
I
40 x 40 x 15 40 x 40 x 15 24001001 to 1500 I 10
Table 9 Hangers and Supports - circular horizontal ducts
Longer Side Hanoer Split Clips Maximum spacing Drop Roll f-ormed and Wrap-round Rod ~hannel Hang r
2 3 4I Fig 1920 amp 22Fig I
mm mmmm mm mm 25 x 25 x 15 IIp to 355 8 40 x 3- --1-_ 2400
2400
2400 2400
70x 6
40 x 5 SOx 5
40 x 20 x 15 40 x 20 x 15 40 x 40 15
10 10 10
356 to 600 601 to 1000 1001 to 1500
19
DW154 Spccijicutioll for Plastics Ductwork
147 Protection specification Any special coatingpaint Unless otherwise stated all support shall be finishes for protection against hostile manufactured in material as specified in this environments shall be advised by the designer
SUPPORT BEARERS
~ 14 Flg16 Inverted profile
angle I ~lIed steel
channel (alternatives) Fig 15 Profile channel (alternatives)
TYPICmiddotAL VERTICAL DUCT SUPPORTS Flat bar clipStiffening frame Outline ofinsulation stiffening frame or tlanged joint (if applicable) or flanged joint
Stiffening framc or flanged Joint
~~-I ( ee notes 10) I
r--~ -++- ~--4==J===4~---
Fig 17 Vertical rectangular ducts Fig18 Vertical circular ducts
The support bearer which depending on ducti tructural opening size could be either channel or angle section may be ll1ilised in any of the following arrangementsshy
a) To support the underside of a flat bar clip in halves (circular)
b) To support the underidc of either the stiffening frame oftbe flanged joint ofaoy duct section
c) To support either a stiffening frame Or a flanged joint below nsing drop rod srudding
20
DW154 Spediraiml for Plastics Ductwork
Arrangement of bearers and hangers (to be read in conjunction with Table 8 amp 9
wbich list material sizes relative 10 duel izes)
KEY Limits refer to actual duct size - insulation is additional - Typical
attachmentv -Atta hment t strucUlrcI to strucUlrc
I I
I - Flat Bar
I - Drop rod or - utlinc of lllddmg In ulillwn (if
applicable)
Alternative 7 drop rod or rt------------ 1 studdmg q I
I I Rectangular
ii i n 1
Fig 21 Rolled or profiled bearer Limit oncFig 19 Wrap-round hanger Limit 55 DIA
V v Drop rod orAllernaUC 1 1 tudding
drop rod or 1
-- -- 1studding and elded bas 1
I I0 -_
Limit 355 DIA Frg 22 Split clips Limit 1500 DIAFig 20 Flat strap hanger amp split clips
21
DW154 Specification for Plastics Ductwork
6PA deElned in J62 appropriate to the airflow pressure acoustic temperature and corrosion
General
15 ACCESSl SPECTION OPENINGS
151 General These are for inspectionservici ng on 1y
HVCA publication DWIl44 Part 7 - General Section 20 sets out the requirements for access applicable to this specification
152 Cleaningmaintenance Designers shall take specialist advice and then stipulate their requirements for the periodic internal cleaningmaintenance of ductwork and of the consequent need for adequate access for specialist cleaning equipment including the size type and locationfrequency of the actual access openings required
Appendix D sets out guidance notes for the consideration of cleaning access and also makes reference to the HVCA publication TR 17 Guide to Good Practice Cleanliness of Ventilation Systems which covers the su~ject
in greater detail
Note A majority of in tallations in which plastic ductwork is used are considered to have a nigb operational risk potential and provision of access should address this
16 REGULATI G DAMPERS
161 General Balancing dampers and control dampers are elements inserted into an air di tribution system or element of an air distribution sy middottem Balancng dampers permit modification of the air resistance of tbe system and consequently cbanging of the airflow rate Control dampers control tlle airflow rate and may in addition provide low leakage closure of the airflow
The deigner shall specify damper locations taking into consideration that good design practice requires a minimum of five times the diameter or width of the shortest side of uninterrupted flow between plant connections and the damper and select the damper type as
characteristics
1611 Balancing damper To achieve the required distribution of air in the ductwork system at inlets andor outlets for [hi purpose the damper blades are set and Jocked manually in position between fully open and fully closed
1612 Control damper To secure dynamic control of the air now in the ductwork system In thi function the damper will always be power actuated and may require to be modulated between fully open and fully closed and to be capable of taking up any position between these extremes In the fully open position the damper should have a minimum pressure drop In the fully closed position it will not necessarily achieve a complete shut off
162 Types of airflow control dampers Airflow dampers of various types are available for specific purposes as follows
1621 Single - blade dampers Single-blade dampers shall consist of a si ngle pi voted blade cOlllained withjn a casing or section of ductwork The blade shall be adjustable tbmugh a nominal 90 angle by means of a quadrant or similar operating mechanism Where automatic control of the damper is required the spindle shall be extended to enable a powered actllator to be mounted
Single-blade dampers shall have a maximum duct width of 400 nUll and a maximum duct height of 400 mm for rectangular ducts and for circular ducts a maximum diameter of 400 mm
1622 Multi-blade dampers Multi-blade dampers shall consist of a number of pivoted blades contained within a casing The blades shall be
22
DW154 Sedicalirm for Plastics Ductwork
adju table through a nominal 90deg angle simultaneously by intershyconnected linkage or gears connected to a quadrant or similar operating mecbanism Where automatic control of a damper is required a spindle shall be extended to enable a powered achlator to be mounted
There is no restriction on the size of duct in which multi-blade dampers or damper assemblie may be u ed Where dampers are required for blade lengths in excess of 750 mm the blades should be suitably reinforced or supponed 0
individual damper blade should exceed 200 mm in width
1623 Iris dampers Lris dampers shall consist of a nUlllber of radialty interconnected blades which open or close within a casing with duct COlll1cctions The blade shall be simultaneously adjusted by a quadrant or similar operating mechanism
Iris dampers shall be installed as specified by the manufacturers operating and installation instructions where the product is unidirectional with regard to airflow
lris dampers are available for circular ducts only in diameters up to 250 mm (it should be noted that the damper casin i appro)(imately twice the diameter of the duct)
1624 Backdraught dampers Air pressure operated uni-directional rectangular (single or multi-blade) with adapters if fitted to circular ducts
1625 Slide and blast gate dampers A damper [lsed as a shut off facility with an externaJ Lide bousing allowing the blade configuration to be fuJly inserted to fully extended for maxiDlUlll air flow
163 Construction
1631 Materials All products shall be protected against cOHosion as necessary and supplied in a fully finished condition as specified by the designer
1632 Dampers used in low and medium pressure systems The following recommendations apply to dampers forming an integral part of ducrwork with pressure classifications A and B air leakage limits
The dampers shaH be constructed to minimise distortion and prevent jammin in operation Th blade shall be sufficiently rigid to minimise movement when in the locked pOSitiOLl
The blades shall be securely fixed to the operating mechanism All balancing dampers shall have a locking device located on the outsid of the case and shall giv clear indication of the actlwl blad position All penetrations of the duct shall be fitted with suitable seals where necessary
1633 Dampers used in high pressure systems Regulatino- dampers used in duc[work sy tems to pressure cJassification C shall meet tbe construction requireshyments specified in 1631 and 1632 with operating mechanisms out of the air-stream
1634 Proprietary types of damper The use of any specific type of proprietary damper shall be confirmed by the designer In all cases proprietary dampers shall meet the relevant requirements of thi specification
1635 Damper casings Duct damper casings hall be constructed to meet th mllllmum
23
DW154 SpeciJimlioll for Plastics Ductwork
leakage Iim its sp cified for th c1uctwork ystem to which tbey are installed
In order to apply the square metre leakage calculatio as detailed in DW143 A Practical Guide to Ductwork Leakage Testing the reference casing area ball be taken as the perimeter ize of lh damper IDultipli d by the equi alent length of Imetr eg an 800 mm x 400 mm duct damper hall have a surface area for casillg leakag p donnan calculated as follow (2 x 08) + (2 x 04 x I
=24m2 casing area
Other pelforlllance ancl rating test methods for damp f and valves are specified in ISO 5129 and BSIE 1751 and are referenced belm a) Leakage past a closed damper
alve BSIE 1751 b) low ratepre sure requirement
characteri t cs BSIE 1751 c) Operational torque le ring
BSEN 1751 cl) Thermal transfer testing
BSIEN 17 I e) Reg nerated sound power levels
ISO 5129
164 Installation Dampers shall be imaalled in accordance will) any re Ievant ISO EN or British Standard 10 aJ bUT lcling regulation and national code of practice as well as the manufacturers recommendations
17 FIRE DAMPERS AND INT MESCENT SLEEVES
171 General Damper or sleeves arc requiTed on duct y~telll where the designer has -tjpulated the
duct wiU penetrate a fire compartment in the majority of application tbermopla ti ductwork is ugtecl where contamlDated corro ive or otherwise exceptional fumes are concerned it is preferable to use tire damp r which are externalJy mounted ie of the intmnescent operated crush typ
24
72 Fit-e rating The damper assembly should have a fUT
resi tance ratin o equal to that of the fir ban-jer it penetrate and ball be fire tested and rated to the timetemperature curv of B 476 Part 20 and 22
173 Intumescent sleeve At the time of writing this specification qualified test results were available for rectangular dampers and circular dampers up to 55 mm diamet r Manufacture have indicated that they are able t provide speci fications for other size and diameters This infonnation should be confirmed b th de igner Various type are available includino
tho e incorporating ruechanical closing plate and those operated anI by expanded iJllUme c nt media
In all ca es fire damp rs and intnmeBcen leeves shall be supplied and in taUed in
accordance with the manufacturer iJlStructioos and COSHH a essm nt
174 Other types Fire dampers of mious types are availabl for specific purpose~ ee HVCA publication DW144 The de igner should )lot (hat materials for con lt1Jction bould be uitablc for the par1icular application
ALL C SES FIRE DAMPERS AND fNT MESCENT SL _VES SHALL HE S PPLTED AND INSTALLED IN A ORDA CE WITH Tf--IE MANUshyPACTURERS STRUCTTONS AND COSHH ASSESSMENT
18 FLEXIBLEEXPANSION dOINT CONNECTIONS
181 General ploperties Tbe material u ed for flexibleexpan ion iojnt~
mu t meet the design r requirements for temperature air pressllrelfe resistance applicable to pl astic duct sy tem vibration and noi e br akout when incorporated into a jointconnection and shall comply ith lh standard of air-tigbtne specifi cl for the duct work sy tem of which it fOlms part (See Figs 23 24 5 26 27 amp 28 for typical con truclion clelai Is
DW154 SJecilimtol for Plastics Ductwork
Expansion joints
Fig23 Moulded bellows type (rectangular and circular)
Fig24
~F aiblc sleeve
__ liding sleeve
~~~~
Sleeve type (circufar)
Fig 25
AIRFLO
COnlinuou~
weld~
Flexible Iceve
PV A HOWN pp SE BACKING FLATS AS FIG 2
Sliding lee c Co1linuou
weld
Flanged sleeve (rectangular and circular)
25
DW154 Specificatiol for Plastics Ductwork
Flexible con ections
Fig 26 Flexible sleeve with clips (UPVC and PP)
--__ Flexible I eve
I
I
I CODn clioD to plant ~
Band clip
Fig27 Welded flexible sleeve (UPVC only)
Plastic)sed PVC slceve ~-- onll11uo1sly welded
onrreclion to planl ~
Fig28 Flanged flexible connection (UPVC and P )
t sp dally moulded flexible flanged connCClitlll
boil
C)nneclion to plant ~
26
DW154 Specificotiol for Plastics Ductwork
182 LOClt1tion Flexible joint are typicltllly lIsed at building expansion joint and fan inletsoutlets Any others required should be indicated on the de ign drawings Care should be taken to maintain alignment across jointsconnections
183 Length Flexible Jomts shall be kept as short as pra middottieable above a minimum eft ctive length of SO mm In no ca e shall a flexible joint exceed 250 mm in lengtb
184 Connections to rectang a ducts With flanged rectangular connections Ule tlexible material shall be held in pLace with flat pIa tic strip of not less U1an 6 mm thick ltlttached to the flanges using uitabJe fixings The more heavy weight type of fleAible mateLial may also be obtained formed into a channel ection with corners fitted to give a neat air tight j int For pigot connections the Be ible material shall b held in place with flat pIa tic trips n t less than 6 mm thick
t 85 Connections to circular ducts With tlanged circular connections the flexibl material shall be held in place with flat plastic backing strips or proprietary clip bands with screw or toggle fast ners
186 Welded flexible connections (Rectangular and Circular) Where the parent and llexibl material are from imilar ba ed products they can be joined to the duct u ing the welding method described in Section 823
19 PROTECT VE FINISHES
191 nles otherwise stated all ductwork shall be mallllfactured in mat fial as pecified in tbis specification Any special coatingpaint fmishes to be provid d by the duct work contractor sball be advisd by th de igner
20 CONNECTIONS TO BUILDING OPENINGS
201 Fanning and finishing building op nings are not the repoJlsibjlity of the duftw( rk contractor and the note that follow are for guidance purpo e only
2011 Openings in brick block or concrete walls shall have inset frames to provide a suitable means of fixing grille louver masking flanges or the tlanged ends of ductwork The illset frames shall be conslnlcted to maintain the structural int grity of the wlll and where applicable cavities shall be suitably lined
2012 Openin s in dry linino partItIons shall have inset frames a 2011
2013 Openjngs in cladding walls and roofs shall have flaoged leevesframes to provide a suitable means of fixing a 2011
2014 Horizontal and vertical opening xposed to oLltside atmo phere hall
be provided with a suitable weathering fini h at the external face especially where profiled cladding is used
2015 Timber framed op nings are not permitted In fj re compart ment barriers
202 Ductwork connections to building openings hall have a flange of suitable profile to permit practical fixing to the openillg frame In selecting the profile consideration shall be given to Tabl~s 2 and 10 in this specitication relating to duct ize and rating Gasket strip or sealant shall be ltlpplied between the tJaoge and building op ning frame
21 DISCHARGEEXHAUST TERMINAL
21 Tbese shall be vertical open ended and designed to meet and comply with current r gularions on contaminated flue The designer hall ensure that the de ign and perf rmance i suitable for its intended purpose Examples of some typical terminal designs are SbOiD in Figbull 102 10 bull 104 amp 105
27
DW154 SpedjimioTl for Plastics Ductwork
22 THERMAL INSULATION
221 The provision and application of thermal insulation to ductwork is not the responsibility of the ductwork contractor
222 Where ductwork is required to be preshyinsulated the specification should be agreed with tbe designer
223 Where the temperature of the air within the duct promotes condensation on the exterior surface of the duct and cause moisture penetration througb the thermal insulation vapour scaling may be required and in this case the most important requirement is to limit penetration of the seal
The extent of any vapour sealing of ductwork thermal insulation and the support method to be u ed must be clearly pecitled in advance by the designer
224 For detailed information on the thermal insulation of ductwork reference should be made to BS 5422 1990 which covers the specification for thermal insulation materials on pipes ductwork and equipment (in the temperature range -40degC to +700degC) and BS 5970 1992 which is a Code of Practic for Thermal Insulation of Pipework and Equipment (in the temperature range -lOOdegC to +870degC)
23 FIRE RETARDANT FINISHES ON PLAST C DUCTWORK
231 The designer should note tbat ductwork constructed to DW154 has no teted fire rating or information see Appendix C
24 REINFORCEMENT OF DUCTS WITH GRP LAMINATE
241 General Where ductwork is required in larg T izes than are covered by Tables 2 4 6 amp 7 or with the increased strength sometimes necessary for industrial use external reinforcement is normally pwvided by applicatioD of glass fibreresin laminate
GRP systems will bond satisfactorily with standard UPVC sheet but for pp it is
nece sary to use a specially prepared sheet with a glass fabric backing incorporated dOling manufactllfe
The detailed techniques of fabrication using GRP are outside the scope of this speci lcation but the following notes are offered for guidance of ductwork fabricators
242 Materials
2421 Quality The laminate is made up of polyester resin complying with BS 3532 and glass fibre complying with BS 3496 or BS 3749 The nominal ratio of resin to glass fibre should be 7030 by weight
2422 Minimum properties The laminate shall comply with the followiog mini mum pbysical properties
Tensile strength - 70 MNm Tensile modulus - 7 Gl m Flexural strength - 140 M Im Bond strength (hetween laminate and substrate Not less than 7MNm Bmcol hardnes Not le s than manufacturers specification
The GRP reinforcement educe the expansion of the parent material but the resultant stre ses arc well within rhe strength of the bond However the Iinear thermal expansion curve shown in Figs 34 amp 35 will serve as a guide
Surface resistivity electrkal propcltles and acoustical propertie are similar to the relevanl unreinforced materials The fire retarding properties of GRP may be improved by the use of specialisl laminating resin
2423 Forms available GRP Laminate should be built up from the separate materials ie resin aod glass fibre in the form of chopped
I strand mat or spray ravings
28
DW154 Spcification for Plastics Ductwork
2424 Workshop conditions Polyester resuls are sensItIve to lmperature and the workshop hould b maintained at a temperature of herween 20deg and 25degC HiOh relative humidities and damp onditions should be avoided A good rate of air change must be pro icled pJeferably by m chanical ventilation
2425 Storage of materials Resin and urin o agents shouJd be stored in dark cool condirions away from the working area and in confonnit with statutor requireshyments for tJle middottorage of flarmnable liquid Because of Ule Limited torage lif of the unmixed resin and curing a eot mal lials ~hould be ch eked before use to enLlfe that they are within the manufacturer pe ified sh If life (usually ix month from the dm of manufacrure)
Glass fi re should be stored separately und r clean dry conditions
243 Surface preparafon
2431 UPVC To achieve the specified bond strengtll the urface to which the GRP is applied mut first be thoroughly cleaned and then etched either by mechanical means or by the use of a suitable solvent
2432 pp with glass fabric backing To achieve the specified bond middottrength the fabric backing must be thoroughly impregnated Witll resin
244 Mixing the materials for use The re in 1 a three part mix compri lng base I sin hardener and accelerator The manufactur rs pecj[ied proportions are critical and th llUxmg sequenc pecified must be meticulously foUowed
The resin has a very limited life after mixing and before u e It is dependent on the characteri tics and bulk of th resin the alllount of hardener the degree and method of acceleration and the workshop onditions
245 Methods of application
2451 General The mixed resin may be applied by hand or b pray c1epoition The operation must b completed within the gel time of th y tern and tbe laminat fully cOI1olidated to achi v the phy ieal properties pecified
2452 Hand lay-up The duct surface i coated by hand with resin Llsing a brush and a mar of gla fibp orked in until full consolidation achieved Th proc is repeated untiJ th requird thicknes i obtained
2453 Spray depo Won The duct surface is coated WiUl re in by spray gun with the chopped glass roving added through a separate nozzle The full thickne i obtain d in layer with con olidation of each layer by hand roller
246 Construction
2461 General M ini mum COllst ructional requireshyments are pe itied ill Tabl 10 for rectangular and Table 1J for circular dUClS
2462 Joints and stiffeners Fig 29 30 31 32 amp 33 hoI TOSS
joint and tiffener for reinforced UPVC and PBPP duct
247 Worki g practices The fabrication of ductwork pecifiecl ill thi document i not affected by the addition of GRP
29
DW154 SfJcdJicatiOt for Plastics Ductwork
Table 10 Minimum constructional requirements shy
Longer Side Minimum Sheet Thicknes and
GRP Reinforcement
UPVC FBIPP 1 2 3
mm mm mm Up to 1000 3 plus 3 plus
06 kgm2 06 kgOIl GRP GRP
1001 to 2250 45 plus 3 plus 06 kgm 12 kgm
GRP GRP
2251 to 3000 45 plus 6 plus 12 kgm 12 kgm
GRP GRP
Cross Joints
UPVCFBPP 4
mm socket amp spigot
as Fig 30 or flanged as Fig 29
75 x 9 flange welded on both sides as Fig 29
75 x 9 tlange welded on both sides as Fig 29
rectangular GRP reinforced ducts
SlifTeners Maximum Spacing Between
JointsSljffeners UPVCIFBIPP UPVCFBPP
5 6 mm mm
75 x 9 flat 800 as Fig 31 or
50 x 50 x 5 plastic or MS inverted angle as Fig 32
or tormer as Fig 33
75 x 9 flat 600 as Fig 31 or
50 x 50 x 5 plastic or MS inverted angle as Fig 32
or former as Fig 33
75 x 9 flat 600+shyas Fig 31 or 50 x 50 x 5 plastic
or MS inverted angle as Fig 32
or former as Fig 33
Note 1 On rectangular duct up to 400 mm longer side no stiffeners are required 2 Applies to Tables 10 amp I I For COlJstructional operating temperature limits refer to Part 2 clause 5A 3 Tables 10 amp II apply to all pres ure classes up lo ]500 Pa
Table 11
Diameter
1 III
lJp to 1000
1001 to 1750
1751 to 2500
Minimum Sheet Thickness and
GRP Reinforcement
UPVC FBPP 2 3
mm mm 3 plus 3 plus
06 kgm 06 kgm GRP GRP
45 plus 3 plus 06 kgm2 18 kgm
GRP GRP
6 plus 6 plus 12 kglm2 18 kgm1
GRP GRP
Cross Joints
UPVCFBPP 4 III
socket amp spigot as Fig 30 or flaoged as Fig 29
75 x 9 flange welded on both sides as Fig 29
75 x 9 flange welded 00
both sides as Fi 29
inforced ducts
Maximum Spacing Between
JointsStiffeners UPVCIFBPP
6 mm 2400
800
600
Stiffencrs
UPVCFBPP 5
mm 50 x 9 flat as Fig 31
75 x 9 flat as Fig 31 or former as Fig 33 75 x 9 tlat as Fig 31 or t()rmer as Fi 33
ote On extruded tube tip to 600mm diameter no stiffenergt are required
30
DW154 Specificatioll for Plastics Ductwork
G - Cross joints and tiffeners
Fig 29 Flange Joint Fig32 Stiffener shy inverted angle
M artiPfCuQkbdd erttpObri) Wl111 RP tlddtlt
_- GRPloliu] lh~
Fig 30 Socket and spigot joint Fig33 Stiffener shy use of former
Fig 31 Stiffener Flat
I Pv FlPP ~ ~lmJaDUA1) d
OMrlQ rrnall 1( tQlS
25 STANDARD COMPONENT DRAWINGS AND ABBREVIATIONS
251 The illustrations in this section not only highlight where applicable geometric limjtations for the de ign and manufacture or ductwork components but also recommend
standard drawing representation terminology and abbreviations for both duetwork components and some of the more commonly used ancillaryplant items
252 Designers and surveyors should note that bills of quantities should provide a full description
3)
---
v
DW154 Spcc(fim(ml for Plastics Ductwork
Fig 34 Linear Thermal Expansion
u c 0 N ro 0)
b 0)
S
sect0
5 oS cl) 0)
~
on ~ ltl
c U
-30 -20 -10 0 10 20 30 40 50 60 70 80 90 TEMPRATURE C
~ V
-
~~c_ ~
~V
V ~
-7 ~
-- ~V ----
v
-6
+14
+12
+10
+8
+6
+4
+2
0
-2
--4
ig 35 Typical Design Stress tor UPVC and P
7
6
r shy 5E
-c E----0 4t) VJ 0)
ci5 0Jl 3
~
0)
Cl
2
1
o
UPVC
1
000
1
1
pp
- r-- shy r----- shy - t--shy I
__0
-30 -20 -10 0 10 20 30 40 50 60 70 80 90 TEMPERATURE C C
Note Figso 14 amp 35 shaded area refers to GRP reinforced duct
32
DW154 Speciicfltirm for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - REC ~NGULAR
Splilt~r Posilion W-mm pliucr
A B c 40]--QOO 1 W - -
601-1000 1 W4 Wf2 -
1001-1800 3 WI W3 W2
FIG DRAWING DETAfiS
tU]36 ATI Straight Duct with socket and spigol joint
rn [037 Straight Duct with flanged joints
[I []38 Straight Duct with flanged joints
rkJ Short Radius Bend
39 Applies to any augl and for duct up to 400 n11n wide
Minimum (I1m31 radills = 100 mm
Medium Radius Bend (a illustrated)
[kJ Applies to any angle
40 Long Radiu Bend Similar but radius = W
Throlll radius = W2 Applies to any angle
- Short Radius Bend with plitlers
I -shy -shy u co - t lt Li--_ 41 t 0 ~ I I I
~ I
L 1W
Minimum waal radius = 100 mm Splitters not required in bend angle less than 45deg
42 QJ1 Square Bend with turning vanes ij
3
DW154 SP(L~ficatioll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - RECTANGULAR
FIG DRAWl G DETADS
43
~
I v
L L Radius Tee with internal deflectors
44
~ Radiussed Twin Bend
45
Imiddot
er Swept Branch
46 U-
Sqoare Tee with Turning Vanes
47
~ f
Breeches Piece
48 0 y l Piece
34
DW154 Specificatioll for Plastics Ductwork
STANDARD COMPONENT RAWINGS - ECTANGULAR
55
54
51
50
53
52
49
FIG
~MX
RAWlNG
DmiddotMAX
EfjMAX
Minimum throat rndius = 100 mm
Rectangular shy Round Transformatioll
Eccentric Taper 225deg max in either plane Spliller are required for angles greater than 225deg and hould bi eet the angle between any side and duct centreline
DETATLS
Angled Offset
OUset Taper Splitters are required for angle greater than 22 0
and shoold bi eet the angl between any side and dUCI centrelinc
Mitred Offset
Concentrk Taper 2250 max in ither plane SpUtters are required for angle greater than 225deg and should bisect the angle between any side and duel c ntreline
Radiussed Offset
35
DW154 Splcilcuthm for Plastics Ductwork
STANDARD COMPONENT DRAWINGS ~ RECTANGU AR
Branch ducl DimCllsions widlh (W) (A)
urnl mm up lO 200 75
300 100 400 125 600 150
Ocr 600 200
FIG DRAWlNG DETAILS
56 poundplusmni~~ Rectan~lar - Flat Oval Transformation
57 [ Square Branch
58 er Angled Branch
Branch dUCI Dimensions wfdth (W) (A)
[- mm mm59 3shy Shoe Branch Up (0 200 75
--shy AIshy + 300 100
400 125
450 MAX 600 150
Over 600 200
Branch duct DimensIOn
rP X width (W) A)
60 - 1--shy _
~ mm mm
Bell Mouth Branch pto 200 75 300 100 t 400 125
600 150 Over 600 200
0=0 61 -
~ Bell Mouth
- shy T 4-5deg M x
--I 1-shy
TJ
62 X I ] I
Tele-scopic Joint I Illustrated with flangeL
X63
SBD Single Bladed Damper
36
---
DW154 Spedicatioll for Plastics Ductwork
STANDARD OMPONENT DRAWINGS - RECTANGULAR
DRAWING DETAILSFIG
64 on-Return DamperNRD shyshy
shyXbull
Multi-Leaf Damper Can be piggoted or flanged oppo cd or parallel blade
Alternative controls areshy
q p [gtshy
J HD65 Hand
~MD otori ed
PO Pneumalic
L-lt
l 13G 66 Blast Gate DamperX X
FireSmoke DampersSleeves
211r Ratinggtshy----
L_-
---
----
r----
Ir-- shy
IL- _-l
2hr
With i tallation frame
67 41 r Rating
4hr
Smoke damper SD
Intumc cent Sleeve L-d
37
DW154 Specijicutiolt for Plastics Ductwork
FIG
68
69
70
71
STANDARD COMPONET DRAWINGS shy REC ANGULAR
DRAVING DETAILS
gtshy Access Openings
AP 6 Access Panel - Rerno able
w [ ~ Access Door - Hinged
I ~le Inspection Cover
le -I reg -lt
~X X Flexible Connection
~ Drop Cheeked Radiussed Twin Bend
U Drop Cheek Bend
I
72 Air Flow SymbolX
38
DW154 Specifim[ioll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - ECTANGULAR
FIG DRAWING DETAILS
73
74
75
76
77
Q
Q
rp---t
~
V- I Ir---I
JL --11
THE ABOVE DETAILS TYPICAL PLENUM
Air Terminal Plenums
Plenum with side connection
Plenum with top connection
Cover plate with connection
Special plenum with connection
elescopic conn ction in direction of air flow
39
DW154 SpecijicotiOll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG
78
79
80
81
DRAWING
-23~---pound3-(MALE) (FEMAJE)
-t=j--_j(--d-shy
--L
~ THROAT RADI S= D AS T NDARD
e ~
THROAT Rjf)lU = D A MU)
DETAILS
Straight Duct With male and female connectors
Straight Duct With flange joint and slip joint
Bend MouldedIFormed Applies to any angle ego 30deg45deg60deg90deg Medium radius bend as illustrated Long radius similar but throat radius 0
Segmented Bend 90deg four section minjmum as illustrated
Other Angles 60deg = 3 sections 45deg = 3 sections 30deg = 2 sections
I
i
40 shy
DW154 Speciicafinll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG DRAWING DETAlLS
82 Segmented Twin Bend Radius = D2 max
May also be fabricated from tube
83 Equal Tee MouldedIFormed
84 -~ 1in Bend MouldedIFormed
85 Taper Concentric 1 0 as iUu trated Eccentric 30deg iJJcLuded angle
86 Short Taper
41
DW154 SpcUicatol1 for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG DRAWING DETAILS
87 30 max Offset
Angle Branch
Bran h dUCI Dimcnsions dia (D) lA)
Shoe Branch mm mm 88 Cl
Off rectanguJur Up 10 200 75 lOO 10 400 125
- 00 150 Over 600 200
Bl1IllCh duct DimenlOns din (D) (A
~-$a-Conical Branch mm mm
89 Also acceptable with Up 10 200 r
full conical surface 300 10
400 125
END VrE -shy 600 150 Over 600 200
90
m 75
100 12 150 200
mm Up to 200
_ 300 400
600 Over 600
iUtred Branch
Shoe Branch
J-L----U ~ Bell oulh Branch
ENDV1EW
93
92
91
42
DW154 Specificatiol for Plastics Ductwork
STANDARD OMPONENT DRAWINGS - CIRCULAR
FIG
94
DRAW G
I
~ 30deg 090deg
Breeches Piece
DETAILS
95 amp-----~ Blank End
~-----p Multi-Leaf Damper Can be piggolcd or fianged opposed or parallel blade
Alternative controls areshyri=-+- L-T~
I
---
LT~
I r- -
-+1
J HO Hand96
bMD Molori cd
PD Pneumatic
tl-shy bull
Single Bladed Damper 97 ~ saD
on-Return Damper Vertical application only 98 m~D
43
DW154 Sf1tcificatioll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG
99
100
101
102
DRAWING
$ I-
2hr
1 4hr
SD
~v I I
CO TINENTAL COWL
DETAILS
Iris Damper
Fi reS moke Dam persSleeves
2hr Ratillg
With installation frame
4br Rating
Smoke damper
Intumescent Sleeve
Access Openings
Access panel - removable
Access door shy hinged
fnspection cover
Discharge Continental Cowl
44
DW154 Sp(Cii(ltJll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
DRAWINGltIC DETAns
-
I
I
~
I I I High Velocity Discharge Terminal 103 I
I
I I
J I I 1 ~--
Offset Stack Discbarge Terminal 104 1
~ I e --(-
I
N
I
I
I~
I I Vertical Oischarge with Weather Cowl 105 I
--1--1 I
I
GAPI I
RTl AL DISC) lARGE WITH W ATIIER COWL
45
DW154 SpecUicatoll for Plastics Ductwork
STANDARD COMPONE T DRAWINGS - PLA TEQUIPMENTIMISCELLANEOU
FIG DRAWING DETAILS
106 ~~~ Rectangular Attenuator
107 ~- Circular Attenuator
108
~ Beod Attenuator
109 J ~(f) Heating Coil
110 J ftte Cooling Coil
III Jc[ Electric Heating Coil
112 X F
Humidifier
113 [H XX Axial Fan
114 ~fB1famp Noo-standard Ductwork Cross hntchillg (of any separate type) indicates by reference to a key any non DVil54 ductwork system
115 2llIIIIJIIIIIll Flexible Ductwork
46
DW154 SJeCUicll(iol1 for Plastics Ductwork
TABLE 12 - STANDARD ABBREVIAT ONS
ABBREVIATION FLL
AD Acces Door
AFF Axial Flow Fan
AHU Air Handling nit
All Aluminium
AP Acess Panel
AT Attenuator
AV Air enninal Unit
BE 81ank nd
BQ Blast ate Damper
CC Cooling Coil
CF Centrifugal Fan
CTA Cross alk Attenuator
CVU Constant Volume Unit
DP Drain Point
EEC Electric Heating Coil
El Expansion Joint
FAl Fresh Air Inlet
FA From Above
FB From Belo
fBPP Fabric Backed Polypropyl-ne Sheet
Flexle Flexible Connection
lexfD Flexible Du t
C False Ceiling CO an oil Unit
fD Fire Damper
FFL Finished Floor Level
FJ Flanged Joint
FOAM Rigid Polyurethane Self xtinguishing Foam
FOB Flat on Bottom
FOT Flat on Top
GAM Galvanised after ManufacttrJc
GRP Glass Reinforced Plastic
GSS Galvanised Sheet Steel
HC Heating oil
HD and controlled Damper
HH Hand Hole
HL High Level
HVD High Velocity Discharge
IC Inspection Cover
ID lri Damper
IFS Intumescent Fircleevc
47
DW154 Specification for Plastics Ductwork
TABLE 12 - STANDAR ABBREVIATION CONTINUED
ABBREVIATION
IU
L
tv1D
MS
NRD NTS
OBO
OE
PHD
PD
PP
PP
PRD
PVC
RFC
RSC
R
SBO
SO
S1 TST
SSL
TA
TB
TO TJ
TP
TV
TV
OS
UPVC
S
V
VAV
50 RSA
FULL
Induction Unit
Low Level
Motor controlled Damper
Mjld Steel
on Return Damper
at to cale
Opposed Blade Damper
Open End
Parallel Blade Damper
Pneumatic controlled Damper
Polypropylene
Self xtinguishing Polypropylene
Pressure Relief Damper
Polyvinyl Chloride
Rolled Form Chamlel
Rolled Steel Channel
R fUnit
Singl Blade Damper
Smoke Damper
Slip Joint
Stainl t el
tructural Slab Level
To Ab vc
To Blow
Top Down (In Direction of Flow)
Telescopic Joint
Test Point
TU111iog Vane
Top Up (In Direction of Flo )
Voles Otherwise Stated
Unpl3sticisecl Polyvinyl Chloride
Underside
Ultra Violet Light
Variable Air Volume
Rolled Steel Angle (Vith Size)
48
DW154 SJeriiflllioll for Plastics Ductwork
A2 DUCT PRESSUREAPPE DXA Ductwork con truct d to DWIl54 will bebullbullbullbullbullbullbullbullbullbullbullbullbullbull
Air Leakage From Ductwork To be read in conjunction with DW143 A practical guide to Ductwork Leakage Testing
CAUTION As highlighted ill both this docul1lenr and DW14 I lot ellough emphasis can be placed 01 the fact that except for high pressure class C the much more stringent ductwork constructional standard brolght about b the general acceptance of DW154 have irtlally negated the requirement for leakage-testing It is essential lO realise lhat except where it is mandatory this doclllllelll is nOl an endors ~lIlent of the rourine testing of ducts bllt purely a guide to outline the procedures for cononnity with the air leakage limits ill Table l Where the specified methods of assembly and
A3sealing of dlcls are u ed a vi ual inspection wil ordinarily sl~fll e for ver(iatioll of a well engineered and a ceptahfy airtight COl1strucrioll WHERE NOT MANDATORY DUCT LEAKAGE TESTING IS GENERALLY AN UNJUSTIFIED AND SUBSTANTIAL EXPENSE
A1 INTRODUCTION L akage from ducted air distribution systems is an Lmportant consideration in the design and operation of ventilatjon and air conditioning middotystems A ductviork t)ystem tbat ba limited air leakag within defiucd limits wiH cnsUft
that tile design characteristics of the sytem can be maintained It wilJ also ensure that energy and operatLonal cosb are maintained at optimum levels DucLwork constlucted and Ulstalled in accordance with DW154 should minimise a level of air leakage that it) appropriate to tll operating static air pre sur in tile system
A4However it is recouuised that tbe environment in wtJich middotystems are installed is not always conducive to achieving a predictable level of quality in term of system ajr leakage and it is therefore accepted that designer may sometimes require tlle ystem to be tested in part or in total It should be ecogni ed that the testing of duct systems add a ignificant cost to the installation and incur some extra tjm within the programme (Se 47 and 64 re mandatory te-sting)
manufactured to a structural standard that is compatible with the system operating pressure There are three classes of duct con truction to eorre pond with the three pre ure clas meations Class A Lo pressure ducts suita le for a maximum positive operating pressure of 500 Pascal and a maximum negative pressure of -500 Pascals Class B IVledium pressure ductmiddot suitable for a rnaxilnuJJl positive operafjn o pressure of 1000 Pascals and a maxllnum negative pre sure of -750 Pa cal Class C High pre sure ducts suitable for a maximum po ilive operating pressur of 2000 Pa cals and a maximum negativ pres ur of -750 Paltcals
LEAKAGE FROM DUCTWORK Leakao-e front pia tic air ducts occur at the joint~ and is therefore proportional to the total surface area orthe du twork in th system Tb level of leakage i imilarly related to tIle air pres ure in th du t system and whilst there LS n precis formula for calculating the level of air los it i generally accepted that leakage will increase in proportjon to pressure to rbe pOvver of 065 The effect of air leakage from high pressure velocit ductwork is critical tn terms of system perfomlan dege energy consumption and the risk of high frequency noise as ociated with leakage These problems are le critical with medium pressure 10 ity systems but should be con idered Low pres mevelocity ducts present the lowe~t
ri k in tenn of tbe effect of leakage on the operation of the s stern
SYSTEM LEAKAGE LOSS As there i no di ct relatLonship between th volume of air conv yed and the surface area f the ductwork sy tern required to match the building configuratmn it is difficult to express air leakage a a percentage of total air volume Similarly the operating pressure will vary throughollt lh 3 system and a leakage is related to pre me the calculations ar comple However it is generally ac epted tbat in typical good quaJjty systems the leakage from
49
DW154 Specificatioll for Plastics Ductwork
each class of duct llnd r operating condition will be io the region of CIa S A low pressure 6 Clas B medium pres un 3 Clas C high pressure 2
A5 SPECIFYING AIR LEAKAGE TESTING Re peeting both the co -t and programme implications a sociated with te ling du 1 for leakage the designer may for example indicate that a particular system is te ted as follow
a) High pressure ducts - all tested b) Medium pr ssure duets - 10 of the
ductwork shall be s eet d at random and tested
c) Low pre sure - unte ed In any case where a random te t i elected for medium pre sure ductmiddot the followin c1au~e is suggested for inclusion by the de ign r
The designer hall elect at random a maxirnwlI of 10 of the dUCl system to bt tested for air leakage The duct hall be tested af the pressure recommended in Table J3 for the assifi atiol for the ectiol1 of the ductwork that is to be tested The tests shall be carried Ollt as the work proceeds and prior to the application of thermal insulation In the event of test failure of the randomlY selected section the designer shall have The right to select two La1her e tiolls at random for resting Where succes ive failures are identified there shall be a Tight to require rhl COl11raCWr 10 apply remedial attention to the complete ductwork system Th contractor shall provide documented eviden e of the calculalions used to arrive (1
the allowable 10 I for the section to be tested and the client or his agent shall willess and sign the results of the test
able 13 Air leakage rates
Maximum leakage of duct work Static
prcssUft Low-pressure edium-prc-sure I Iigh-prebull me diJfercntial Class A Class B Class C
1 2 J 4 Pa Litres per second per quare metre of surface area 100 054 018 ZOO 084 028 300 110 037 400 132 044 500 153 051 600 058 019 700 064 021 800 069 023 900 075 025
1000 080 027 1100 1200 1300 1400 1500
029 030 032 033 035
1600 1700 1800 1900 2000
036 038 039 040 042
Note Recommend d mean test presures are highlighted iD bold type with the actual selection being left to tll test operator
50
DW154 Sfeeiieaioll for Plastics Ductwork
A9
A10
and air leakage classification for the y em under test
DESIGNERS CALCULATIONS The designer can middotaJculate with reasonable accuracy the predicted total loss from a ystem by
a) Calculating the operatin presure in each ection of the sy tern
b) Calculating the surface area of the ductwork in each correspondin pre lire s ction
c) Calulating the allowabl~ los at the operating pressure for each ection of the system (see table 13 for allowable leakage figures)
VARIABLE PRESSUR S IN SYSTEMS De igner can achieve significant co t saving by matchina operating pressures throughout the system to constmctional standard and appropriate air leakage testing eO the practice of specifying construction tandards for whole duct sy tems based on fan discharge pre sure may incur unnece sary costs on a project For example ome large sy terns ould well be classiC ed for I akage limits as follows
Plant room risers CJas C Main floor distriblltJou CIa B Low pre sure outlets Cla A
A6 SPECIAL CASES There may be ~itLlations on a project where circumstance dictate thal pecial consideration be given to containing air loss s eg a long mn of duclwork may incur a di -proportjonate level of air 10 s In ca es such as thi example the designer can specify an improved tandard of airtighmess ie 80 of alJo~able 10 s for la B Ju ts The designer sbould not specif a CIa C t sI at CIa s C pressure for a CIa s B ducl
A7 SUGG S ED RANGE OF TES ING
A8 TESTING OF PLANT ITEMS Items of inline pJant (eg Fig 106 to 115) will not normaUy be included in an air I akage test The dllctwork contractor may indud such itelllS in tbe te t jf rh quipm ot has a certificate of COnfOlnlity for Ihe pres ure clas
bull High pressure duct bull Medium pre sure ducts bull Low pre sur ducts bull Exposed extract syst ID bull Ceiling void extract
systems bull Secondary ducts from
VAV or fan coil units bull Flexjble duct bull Final connections and
branches to grille and diffusers
100 test See A5 Untested UDt sted
Untested
Untested Untested
Untested
SI
i
DW154 SJecijicafion for Plastics Ductwork
ig 116 Permitted leakage at various pressures
Leakage in litres per second per square metre duct surface area
Vgt
o ltgt 0 ltgt N
ltgt Cgt
0 0 cc
0 0
~
g =
g ~
c 0
J
ltgt 0 I
~ ] tn
ltgt ltgt
In ol
~ 0 ~ 8 ~
~
c ltgt ltgt
~ CJ
~ ~ ~ ~ 8
0shyij
~ ~ ~ t
ltgt ltgt 00
l
~
~ Q
c C
~ rshy
e ltgt
I 1
I Cgt ltgtv
c Co ~
~~ ~ 10
I
0 Cgt
fJshyq 410 ) 1 ltgt
ltgt N
~ shy ltgt ltgt
~ I 1
c
52
DW154 Specificatio for Plastics Ductwork
Example of a completed test sheet Test No
General
Name of job N~ jC43Pt(r2lef Building Repound ~(~~0
Part 1 - Physical details
a Section of duct work to be tested ~(diffPIfff~el1f3rd Floor
b Drawing Number g91~~ c ssure aSSJ L atlOn V~Jl~IRfYgtg~~lPre Cl T Class C
d Test static pressure -(9 raErq~ ~~~~-~~J~~~ ~~ ~~~~ll
Leakaoe factor 9~-tre3$ecMz I OM REFTOTABLE 13)e b bullbullbullbullbullbullbull
f Surface area of duct under test Q~tJJItetre$ CPROMCALCU TIO BELOW)bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull ampampamp bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull
g ]Vlaxi mum permitted leakage -~ (~i~~0 ~~r~~ ~~~l-~-11~ ~~~Q
Part 2 - Test particulars
a Duct static pressure reading 9QFt~q~ ~ middot~~~1 ~~
b Manufacturer and type of liow measuring d vice (-~~~cJ~Y-9Q7EYg c Range of measurement of now measuring device QtP)OQ~(e~~~0I~~~~1~I~ ~~~~~~W~
d Reading of flm measurin o device pmiddot IFROM RIO)ftscag ~
I (DERlVED [ROM CHART SUPPUED WITH RIG US 0 ud)1e Interpreted air flow leakage rate ~(~~~f~~~ (~l~~~~~~~~~~~~~~~~~I
f Duration ~~~~~norn~allY l~ lnil1Ut~~d~~~ it1~ W~ Date of test ~(lITled ut by Wltll s ed by ~ ~
(~lJ MIJLrr) (Si~rrfltJUYJ
Printed Name 1~g0f~ Printed Name ~~Y~9~ and Company 7jl~~~~~( UJd CompanY AB COII$Itallt8
Width and depth or diameter
Periphery ength Area
millimetreS millimetres metre qL1are metre
800 x 750 3100 1755 5440
600 x 650 2500 557 1193
300 x 300 1200 120 144
305 din 958 700 670
250 dia 785 450 353
TOTAL 8000
53
DW154 Specijilarion for Plastics Ductwork
pA XB
Guida ce No es For he ransport Handling and
Storage of uctwork
avoid damage to adjacent duct panels In somc ca es particularly on con acts calling f r repetitive sizes the use of timber jigs and spacers may be justified Where reduced bulk and greater protection are major factor such as consignments for export transporting ductwork in L shape sections may justify the increa ed ite as embly co ts
It is recommended that before a contract is finalised that consideration is given to the subject of site acces material handling and storage as tbcy havgt a strong influence on the cost efficiency of the overall activity of ductwOlk installation
B3 Handling To minilnise th risk of damage duct sections should be clearly identified and deliveries to site should be closely linked to the installation programme so as to avoid accumulation of
B1 Storage and Handling of Ra Material Material should be stored in suitably designed racking out of direct unJight Where possible the e racks should be metal to earth Edges of cut she t may be harp and protective gloves are advised Wearing teel toe-capped boots is recommended Most pIa tic sheet is manufactured with smootb mfaces andor is suppLied with protective coating Care must be taken to prevent accidental lippag of stacked materials Beiuoshy good electrical insulators the movement of stock unless earthed will allow the build up of stati All stock shapes are chemically stable at normal temperature Whil t some raw materials used in their manufacture may themselves pre ent a toxic hazard once incorporated into the lOck bape they no long r constitute such a hazard and no dermatitic bazard are known nor are any
unfiJied ductwork and minimise double handling It is important to recognise that ductwork panels joint and corners arc susceptible to damage and care must be taken wheu band ling such material through a site During handling individual item of duct work may be liable to light cross sectional deformation until thev become an integral pan of a completed ductwork system Whilst this may temporarily detract from its intended appearance thi deformation will not have any detrimental effect on the functionality of the finally a semblecl system Installation of duct work and asociated plant items ill illevitably involve manual handUng The responsibi Iiry of employers and employees to a ses the risk of personal injury during mallual handling operations is et out in the HS E publication L23 Guidance on Manual Handling Regulations 1992
environmental problems expected 84 Site storage
B2 fransport Large capacity vehicles with high-sided open or closed-top bodies are tlle mo t suitable for the transport of dllctwork Careful consideration should be given to the
Adequate floor space IDust be provided within tbe building for the site storage of ductvork Such storage shalt make due allowance for thc stOf(ne of ductwork in stacks such that access ~ egt
between them is of sufficient width to pennil the removal of item without interference to
unloading of transport on sit a not all siJes b n fit from the material handlino- and access facilities that exi [ in a manufacturing workshop such as crane- fork-lifts or loading bay Site handJiog facilities along with
adjoining sta ks Ductvork components should be positioned so a to avoid crushing Ductwork of small panel size may be stored horizontally however care should be exercised to ensure that tack sizes are limited 10 within
ehicular acce s restrictions may itilluence the type and ize of transport to be uWised
engtlls of ductwork should be positioned 0
the tmctural strength of the duct sections to prevent distortion of the lower sections within the stack
as to avoid crushing Lengths Witll projections such as branches and bends i1anges girths damper quadrauL should be loaded so as to
54
DW154 S1tciic(ltioll for Plastics Ductwork
85 Internal cleanliness of new ductwork The site storage of ductwork introduces the important cODsideration of maintaining the internal cleanliness of the ductwork R feren e should be made to HVCA documentshybull DWffM2 Guide to Good Practice - internal
Cleanliness of New Ductwork Installations If the above conditioDs can not be satisfied consideration should be given by tJle designer to amending the specification to include for Po t Installation Cleaning as covered by tJ1C HVCA documentshybull TRJ17 Guide to Good Practic - Cleanliness
of Ventilation Systems
APPE DIXC
Fi e Retardant inishes C1 Improvement in the fire retardancy of plastic
ducts can be achieved to varying degrees and is wholly dependent llPOll the surface coating laminating resin selected and construction specification adopted In some instances smoke emission is coILSidered equaUy with other speci fication requirernen ts of the materials resistance to ignition and bumjng It is therefore important for design rs to establ ish the clients and officers detailed requirements and not rely on a tbird party interpretation of fire resisting or fire retardant Where possible the specification should refer dir etly to compliance with a British or European Standard identifying the specific sections applicable There are various types of resin and mat rcLnforcements that can achieve a Class 1 surface spread of flame ratin o when tested according to BS476 Part 7 (1987) This test puts materials illto Class I - 4 in descending order of perfoDllance according to the rat and extent of flame spread over their surfac under standard beating conditions Materials should also be tested for flre propagarion to BS476 Part 6 (1989) Tbi tesr measures the amount and rate of heat evolved by the material when subjected to standard heating
conditions Test results are given as an index of Perfonnance (i) whicb is based on three sub indices (iJ (i1) (h) The higher the value of the Index of Performance (i) the greater is the material s contribution to fire growth The higher the value of the sub-index 0) rhe greater the ease of ignition aod flame spread The highest product performance classification as defined in Approved Document B of the Building Regulations is Class O This is acLlieved if a material surface of a composite ploduct i~ either a) composed throughout of materials of
limited combustibility or b) a Class I material which has a tlre
propagation index (i) of not more than 12 and sub-index (i l ) of nor more than 6
01 J Class 0 is not a cla$sif1cation identified in any British Standard test
There are resin system reported to be classified to Class O when tested to BS476 Pcl1S 6 and 7 however designers need to ensure that such sysrems can be applied to their proposed design In propriety resinmat system available the fabrication techniques and COITect application are critical to the integrity of the reinforcing and clas ificatiol1 For example in some systems the u e of a non-fire retardant gelcont on a fire retardant substrate would reduce the classification For further information see HVCA publication DW144 Appendix D
55
DW154 SplCijiClIliol1 for Plastics Ductwork
x Guidance otes For nspectmiddoton Servicing a d
Clean-ng Access Openings
D1 GE ERAL This appendix highlight in ummary fOI111
the acce considerations that hould be made by the design r iD terms of inspection servicing and cleaning Having considered the seop and the design of the dUCI work system relative to the guidelines outlined below the designer should clearly indicate which levels of acces should be incorporated into the manufacture of a new duct work system (See Table 14 and Note I b low it
D2 DESIGN CONSIDERATIONS
D21 In ptction and servicing requireshyments are set out in Section 15 of Lhis specification
D22 Cleaning requirements are set out in the HVCA pubUcation TRl7 Guide to Good Practice Clean Lines of Ventilation Systems and the guide tates The precise location ize and
type of access would be dependent on the type of ductwork cleaning inspection and te ting metbods to b adopted Care protection and standards of cleanliness prior LO cOlllmisionin o
are set out in th AV A publication DWITM2 Guide to Good Practice Internal Cleanliness of New Ductwork Installations and th guide state Wh re specific limits of cleanliness are required ductwork sball be cleaned after installation by a spcialist cleaning contractor It will b in the interests of tht desioner botb financially and practically to cunsider employing a specialist c1eauing contractor at tbe
outset of a contract to internally clean newly installed ductwork prior to bandover This approach would reali e the following benefit shyi) Tb actual numb r of cleaning
access panels could be detennined to suit the method of cleaning to be adopted (This may be 1 s than the maximum requiremen listed under Lev 13 of Table 14)
ii) Clear directions could b given to the ductwork contractor as to tJle size and location of cleaning access panels that are required to be fitted during the mauushyfaclunng pro s
iii) The specialist cleaning operation prior to commi ioning vould enable the cleaning contractor to verify the practical acee requirement for the future cleaning operation associated -vitb a regular maintenance programme
iv) A specialist cleaning operation prior to commissioning would allow the designer to omit from the speeilicatiolJ the DWrrM2 requirem nt for factory sealing protection wipe downs and capping-off
v) Specialist Ieall ill 0 to the measurable standard defin d in TR17 will allow an objective definition of cleanline to be achieved
Car ful consideration must be gIven by the designer to the practl aJ problems associated witb the manufacture and fitting of suitably si Led access panel on small cross section duct and on the circular faces of rouod and flat oval ducts in particular
D23 Special con ideration must be given by the de igner to the practical problems associated with gaining personnel access to heavily congested ceiling areas and multi-la red du twork systems This approach would avoid
56
DW154 Spfciication for Plastics Ductwork
the possibility of access panels being D3 ACCESS 0 IN-LINE EQUIPMENT incorporated into a ductwork system at the This appendix unly covers acc il1spection manufacturing stage that were later found in through the ductwork body adjacent to an item practice to be inaccessible for either ervicing of in-line equipment and not openings in the or cleaning activities equipment itself
able 14 Acce requirements for inspection servicing and cleaning
HVCA PUBLICATIO REFE NeE (uidtgt 10 Gund Prartict
Adjace t OW144 Cleanliness orVcnlillltio S~lcr~ fRjJ7
in-line LeyeJ 1 Level 2 Level 3 ite sequipment pcdionSen lcin~ Section d C1eaniJl( SUn(O)lnspc lion Palle ltk~m_n
2011 (minimum OiL Jubje-ct to duct ~zel (ft~ -Panels
Control Da pcrs One (inspection) 203 One 300 mm x 200 mm Both sid Fire Dampers One (sCTjdJl~) 20211 One 300 0101 x 200 mm One side HeatingCooling Coils One (inspedion) 20213 One 300 mm x 200 mm (lIpstream) Both sides Attenuators (rectangular) None required One 300 mm x 200 mm (downstream) Both sides Attenuators (circular) one retluired One 300 mm x 200 mm (downstream) One side Filter Sections One (inspection) 20212 one required Uoth sides Air Turn Vanes None requjred None required Both sides Changes of Direction None required one required One side In-Duct FansDevices One (inspection) 20213 None required Both sides l
1 In the absence of any indication by the designer only Level ) access will be jncorporated into a new ductwork system
2 Tbe panel izes associated with Lev lis I and 3 acee s ar e middottablished by reference to Section 20 of DW144 and Section 2 ofTRll7 respectively
57
DW154 Speclfifatio for Plastics Ductwork
pA XE
B-bliography Included in this Bibliography are technical pUblications which may be of interest (0 ductwork designers fabricators and erectors and to tho e in the heating ventilatlng air conditioning industries generally nquiric should be made of the relevant organisation at the address quoted Since its publication other addresse contained within 0V154 mav have changed and some pubJicalions may have been superseded
HEATING AND VENTILATING CONTRACTORS ASSOCIATION
4 Palace Court London W2 4JG Telephone 020-7229 2488 Fax 020-7727 9268
Orders fo FlY A Publications Old Matlsion House Eamont Bridge Penrith Cumbria CA 10 2BX (Telephone 01768 864771 Fax 01768 86718) Email hvcapoblicationshvwelfarecouk DWn 44 pe ilicatiun for sheet mctal duclwork (Iow- mediulllshy
and high-pressure) 1998) DWIl4 A practical guide to dUGI ork I akage te ting
(revised 2000) DWII54 Specification for plastic~ duct rk DW171 Guide to good Practice for kitchen venlibtion system DW191 Guide to good pracuce glass fibre ductwoJk DwrrMI Acceptance cheme for new products - Redangolar cro
joint classification Guide to good pra tice - Internal cleanliness of new ductwork installations Guide to good practice for the design for the Installation of lire and smoke uampers
J 1Other puhlications
HampV safely guide 5th edition JS2 Tool box talks JS5 Weldlng Safety booklet JSI9 afety facts bo klet Fact sheets 1-24 2nd edition JS2J COSHH manual volume 1 Advice on compliance with the
regulations 1521A CO I-rH manual volume 2 Asses mcnt h ets JS23 Ri k management manual TR3 BrazinltT and bronze welding of copper pipework cUld sheet
(I 976) TR5 Welding of carbon steel pipework (1980)
TR6 Guide to Good Practice for Site Pre sure Testing of Pipework (19 0) Guide to good practice cleanliness of ventilation Ylem
CHARTERED IN TITUTlO OF BUILDING SERVICES E G EERS Delta House 222 Balham High Road London SW12 9BS rTelephone 020-8675 5211 Fax 020-8675 5449) CIBSE Guide Volume A Design Data Volume B In tallatiol1 and quipment Data Volume C Reference Data
CommlssioniJIg Codes These Codes eover the preliminary checkS eUing to work and regulation of vanous catcgories 0 plan The Codes give a guide to design implications Series A Air Distnbution Systems Series B Boiler Plant
ri s C Automatic Conlrol ystems Cr1es R Refrigerating Sy terns
Sene iN Water Distribution Systems
Technkal Memonllda TM 4 Design Notes for the Middle East TM bull Design otes for Ductwork TM 13 Minimi iog lhc Risk of egiounaires Disease
Research Reports RROI95 Ventilation system hygiene - A review of published
infomlatioo on lhe occurrence and ffects of Olltamination Rl~02J95 Air-to-air heal rec v ry RR0395 rnfluen e of HV C on smoke detectors
ATlONAL ENI [ERING SPECIFICATION LfMITED Southgatc hamber 3739 Southgate Street Winchester S023 9EH (Telephone 01962 842058 Fax 01962 R(8982) BUfLDING S RVICES RESEARCH AND [ ORMATION ASSOCIATIO Old Bracknell Lane West Bracknell Berkshire RG 12 4AH (Telephone Brackl1eU (01344) 426511 Fax 01344 487 -7 )
Application Guides AGln4 De tglJing Vana~le Volume middotylans for KOOnl
iir Movement AG1I91 Commissioning of V Sylcms in Buildings 11 6194 Fire Dampers
B) 94 cntiJalion or KitcneTls
AG389 The Commls ionin of Air Systems In Buildmgs AH2192 Commissioning of Bern - A ~ode of Practice TN2417 I Fire Dampec il) Ventilating Ducl
BEATING VENTILATING A AIR CONDITION G MA UFACTURERS ASSOCIATIO (HEVAC) HEVAC Henley Road Medmenham Marlow Buck SU 2ER (Telephone 01491 578674 ox 01491 575024 Emoimiddot infofetacouk)
Publicatjons Air Diffusion Guide Guide to Air Handling Unit Leakage Testing Guide to Good Practice Air Handling Unit Real Room Acoustic ~ st Procedure Specification for the ertiiicatioll ofAir Filters Method of Test for Water Rejection PerfOnTlatce of Louvrcs Subjected 1(1
Simulated Rainfall Test Procedure for Acoustic Loo cs Specification 10 Floor GrilJes - Types Performan e and Method ofTest Specification for the Determination of the Collection Efficiency of SilJ1d
Trap Louvre Domestic Mechwlical Vclltllalion Systems with Heal Recovery Fan Application Guid
~an and Ouctwork Installation Guide Guide to Fan Noise and Vibration
pecification of Requirements for JallJral Smoke and Heal Exhausl Ventilators
pecification for Powered Smoke and Heat Exhaust Ventilators
Specification of Requirements for Smoke Curtains Design Gujue of Smoke Ventilation for Single Storey Lodustrilll Building~
Including those with Mezzanine Floor and IIi Racked Storage Warehou es - Issue 3
Guidance for the Design of Smoke entilation YSlem for Covered and Undergrollnd Car Parks - lssue 1
Application of SOloke Control Equipment and Syst m Guid to Good Practice - Isue J
58
DW154 Sp(C~tiifitiol for Plastics Ductwork
BRITISH STANDARDS INSTIT TION Sales Department 101 P ntooviLle Road London NI 9ND (felephone 020-78 1 78801)
CP 413 1973 Ducts for building ervices
SS 476 Fire tes on building matenals and lruc(ure
Part 4 19 4 Non-combustibility lest or materials
Part 6 I Fire propagation lest for materials
Part 7 1993 Surface spread of tlarnJ tesls for materia
Part 20 1987 Fir resistance of elements of construction
Part 21 1987 Fire r sistlUlce of loadbeanng elements of construction
Part 22 1987 Fhe istallceofllon-loadbearing elemcllts ofconsttuclion Part 23 1987 Contribution of componcnts to the fire resistance 0 a
structure
Part 24t987 Fire resi lance of wl1lilation ductl
SS 5588 nan 919 0 Fire Precautions III thc desIgn and OOSlnJ lion of buildings
S 729 1971 Hot dip galvanized oatiugs (or irOIl aod stcel articles
BS 1449 Steel plate sheet and Irip
Pan 11991 Carbon steel plate heel and strip Part 2 1983 Stainless steel plate sheer and strip
and
B middotENJOI49-2 996 BSEN 10149- 1991)
BSEN 10131 1992
BSEN22063 Sprayed metal coarings 1994 Protection of iron and steel by aluminium and zinc against
atmospheric cOlosion Irotectiotl of iron and ste I against corro ion and oxishydation at elevared temperatures
BS 353 1981 Glossary of lerms relnting to thermal insulation
BS ISO 1479 Self-tapplngscrewsandmetallicdri c crew
B -lSO 7049
1994
B 4800 1989 Painl colour for building purposes B 4848 l0 rolled structural steel sections
Part4 1972 Equal and unequal angles BS 5422 1990 Specification for the use of therm illuating matcriulS
SS 5720 1979 ode of practice for mechanical veutilating and air C 11shy
dirionin bull in building
l3S PR 12814-1 Bend resting for plasric welds
SS PR 12814-2 Tensile testing for plastic welds
SS PR 13067 Appro altesting for plastic welds
BS PR EN I 100-] Vi ual in pection ofplaslic welds
SHEET METAL AND AIR CONDITIONING CONTR-CTORS NATIONAL ASSOCIATION INC (SMACNA) Headquarters 420 I Lafayeue Center Drive Chanlilly Virginia 2051-1209
Mailing Address pa Box 221230 Cbantilly Virginilt120 153-1230
Telephone (703) 803-2980 Fax (703) 803-3732
Accepted IJJdustry Pl3Gtice for Industrial Duct Constnlelion 197 ) i-rchitecmral Sheet kwl Manual ([993)
Comractors Guide lor Modification 10 ooslruerion Colllraets 1993 Ducted Eleclric Heat Guide for ir Handling Ssrerns (1994)
En~rgy ollservatioD Guidelines (1984) Energy Recovery Equipment yslClllS (199l
Fibrou GIns Duct onS1ntClion Standards (1992)
Fire Smoke amp Radiation Damper In tall Guide for HVA Syst ms (1992) Guide t leel Stack 1(95)
HVA Air Duct Leakage Test Manual (19 ) HVA COlllmissioning lvlanual (1994)
H A Duct Construction Standards-Metal amp Flexible (1995) Addendum 01 (Nov 1997)
HVA Duct Systems Inspection Guide (1989)
HVA ySlems-Application (1986) nVAC ByternS-DLlct D ign (1990)
HVi Systems-Testing Adjusting amp Balancing (1993)
indoor Air Quality Manual (1993) tcheu quipment Fabrication Guidelmes (1990)
Managers Guide for elding (1993)
Rectangular Industrial Duct Cons1TUction Standards (19 0) Round Industrial Duct oustmction Standards (1977)
Sei mic Restraint Manual (1991) (wl Appendix E 1993) SMACNA Ma le Index ()fTechnical Publications (1995) Tbennoplnstic Duct CPY ) Construction Manual 1994)
DEPARTME OF THE ENVIRO MENT (Publications Centre) H Stationery Oflice 5 Nine Elms Lane London SWS 5DR
MampEJ 011972 Electrical in tallat1011 in buildings ( ew Editiou)
IampE 0319 Healing hot and cold wat r steam and gas losla1lations for buildings
M amp - No4 1970 Central heating and hot and cold ~ ateT in tallations for
dwelling
M amp ENo100 1971 Mechanical ventilation for building~
ASSOCIATION FOR SPECIALIST FIRE PROTECTlO As ociation House 235 Ash Road AJdershot Hampshire GUl2 4DD
Telephone OJ25221322 Fax 0 J252 333901
lublicalioos Fire Ratcd and moke Outlet Ducrwork An Industry Guide t Design and InSlalla lioll
HEALTH AND SAFETY EXEC TIVE Rose Court 2 Southwark Bridge London SEl 9HS Telephone 020-7717 6000
TWJ THE WELD G TlTUTE Abington Hall Abington Cambridge CB16AL Telepbone 0 J223 89162
Publication DatJ Oil w~ldll1g of lhermopla lics
59
DW154 wciiwlioll for Plastics Ductwork
A -=--DIX
Factors
Specific gravity shy pp = 091 approx UPVC = 14 approx
Some miscellaneous conversion factors
To convert
Length Inches to millimetres Feet to metres
Multiply by
2540 03048
To convert
Millimetres to inches Metres to feet
vIultiply by
003937 3281
Area Square inches to square millimetres 6452 Square millimetres to square inches 000155 Square feet to square metres 00929 Square metres to square feet 10764
Volume Cubic feet to cubic metres Cubic feet to litres Gallons (UK) to litres
002832 2831 4546
Cubic metres to cubic feet Litres to cubic feet Litres to gallons (UK)
35315 00353
022
Mass Ounces to grams Pounds to kiJograms Tons to tonnes
2835 04536
1016
Grams to ounces Kilograms to pounds Tonnes to tons
003527 2205
09842
Volume flow Cubic feet per minute to cubic Cubic metres per second to cubic
metres per second 0000472 feet per minute 2119 Cubic feet per mIDute to litres Litres per second to cubic feet
per second 04719 per minute 2119
Motion Feet per minute to metres per second 000508 Metres per second to feet per minute 197
Pressure Inches water gauge to millibars 2491 Inches wateJ- gauge to pascals (Pa) 2491 I Pa = I ewton per square metre = 10-2 millibars
60
Heating and Ventilating Contractors Association Esca House 34 Palace Court London W2 4JG
Tel 020 7313 4900
e-mail contact Itvcaorguk web site wwwhvcaorguk
Fax 020 7727 9268
DW154 Speciliwriml for Plastics Ductwork
135 Stiffeners
1351 External stiffeners Shall be fitted as specified in Tables 67amp 1 I and Fig 13
1352 Internal stiffeners The use of internal stiffening or bracing hall be acceptable if deemed neces ary and appn ved by the designer
f 36 Expansion joints Where the corrfiguration of the ductwork does not provide for movement due to temperature
Cross joints - circular ducts
change or where such movement is restricted by branches or attachments expansion joints should be fitted (See Section 18 Flexible Expansion joint connections)
It is the responsibiLity of the designer to identify the position of any necessary expansion joints based upon design parameters for the individual systems (See Figs 23 24 2534 amp 35)
Design Note Examples of expansion joints shown are not suitable for movement exceeding 30 mm
Fig 10 Socket and spigot joint (UPVC and PP)
ConLinuous weld joim on ite Ontinuous weld
crlr~l
Fig 12 Flange joint (UPVC and PP)
Continllous wcld
boil
Continuous weld or Solvelll cement
Solvelll ccmcnl joim on sile
Fig 11 Socket and spigot joint (UPVC only)
Stiffeners - circular ducts Table 5 Fastening centres shycircular duct flange jointsFig13 Flat
flat conljnlJou~ly welded Diameter Pitch Bolt Size
max
1 2 J 11
1 shy -~
mm mm mm Up to 600 100 8 with washers
601middot1000 100 10 with washers - ---I
1001middot1500 100 10 with oversized washers
1
Minimum offourfixings
17
DW154 Specifiiutiofl for Plastics Ductwork
Table 6 constructional quiremen s - circular unshy inforced U VC
Diameter Minimum Joints Stiffeners Maximum spa ~in r
Sheet between Thickness Jointsl tiffcners
1000 Pa 1500 Pa
1 2 3 4 5 6 UD mm mm mm mm
UO to 600 3 socket amp spigot as Figs 10 11
or fla ged Fig 12
601 to 1000 45 socket amp spigot 50 x 9 flat 2400 2400 as Figs 10 11 welded bo sides
or Oanged as Fig 13 as Fig 12
1001 to 1500 6 Hanged 75 x 9 flat 1200 1200 as Fig 2 welded both ides
as Fig 13
Applies 10 Tables 6 alld 7
Note 1 For constructional operating temperature limit refer to Part 2 luu 54 2 To allow for conicleration or extruded se lions or fabricated component the materia] tllicknes i hawn a nominal
Table 7 Minimu onstrucfional requirements shy circular un-reinforced PPS and
Diameter Minimum Joints Stiffcners Maximum pacio Sheet between
Thickness Join sStiffener 1000 Pa 150n Pa
I 2 3 4 6 mm m m mm
110 to 500 3 socket amp spigot as Fig 10 or flaoged as Fig 12
501 to 750 45 ocket amp spi~ot
as Fi 10 or Uanged as Fig 12
751 to 1000 6 tlanged 50 x 9 Oat UOO 12 0 as Fig 12 welded nth sides
as Fig 13 1 1 to 1250 6 flanged 75 x 9 flat 800shy 800
as Fig 12 welded both sides as Fig 13
1251to~ flangcd 75 x 9 Oat 600 600 as Fig 12 welded both sides
as Fig 13
18
DW154 Sped(icalirm for Plastics Ductwork
PARTS
Hangers an Suppo ts
14 GENERA
141 Supports are an e sentiaJ part of me ductwork system and their supply and in tallation are normally the responsibility of the ductwork contractor The principl s are a I-rvCA publication DWIl44 Part 6 Section 19 and should be read in conjunction with this document
Design Note Designers may pecify specific requirements wbich will supersede guidance given in DW144
142 Rectangular ducts abl 8 give the- minimum requirements for
hanger and supports for un-reinforced ductwork
143 Circular ducts Table 9 gives the minimum requirements for hangers and upports for uD-reinforced ductwork
144 Vertical d cts The design of supports for vertical duct is dictated by site condition and where practical duc hould be upported at 4000 mm interval or where tbey pa s through a floor (but n ver exceeding 4500 mm) see Figs 17 amp J8
145 External ducts Where ducts are external to buildings and may be ubject to wind loading support should be plac d so as to restrain ide tl1ruSt and should allow axial movement as neces ary It is the respon ibility of me de igner to calculate the effect of the particular prevailing condition and to define any special upport requirement
146 Expansion joints Support shall be designed to permit axial movement only and shall e provided on eitl1er ide of expansion joint
I 1shy
I~
mm -Jp to 400
401 to 600 601 to 1000
Table B Hangers and Supports - rectangular horizontal ducts
Hanger Bearer Drop Roll Formed Rod
Long r Side
Cbannel ~-shy ~
---shy
Maximum ~pacing
4 52 3 _ -c Fig 15 - Figs 14 15 16 amp 2J
shy
mmm mmmm 240025 x 25 x 16 40 x 20 x 15 8 240040x20x15 40x 20 x 15 10 240040 x 20 x 1~510 40 x 20 x 15
shy
I
40 x 40 x 15 40 x 40 x 15 24001001 to 1500 I 10
Table 9 Hangers and Supports - circular horizontal ducts
Longer Side Hanoer Split Clips Maximum spacing Drop Roll f-ormed and Wrap-round Rod ~hannel Hang r
2 3 4I Fig 1920 amp 22Fig I
mm mmmm mm mm 25 x 25 x 15 IIp to 355 8 40 x 3- --1-_ 2400
2400
2400 2400
70x 6
40 x 5 SOx 5
40 x 20 x 15 40 x 20 x 15 40 x 40 15
10 10 10
356 to 600 601 to 1000 1001 to 1500
19
DW154 Spccijicutioll for Plastics Ductwork
147 Protection specification Any special coatingpaint Unless otherwise stated all support shall be finishes for protection against hostile manufactured in material as specified in this environments shall be advised by the designer
SUPPORT BEARERS
~ 14 Flg16 Inverted profile
angle I ~lIed steel
channel (alternatives) Fig 15 Profile channel (alternatives)
TYPICmiddotAL VERTICAL DUCT SUPPORTS Flat bar clipStiffening frame Outline ofinsulation stiffening frame or tlanged joint (if applicable) or flanged joint
Stiffening framc or flanged Joint
~~-I ( ee notes 10) I
r--~ -++- ~--4==J===4~---
Fig 17 Vertical rectangular ducts Fig18 Vertical circular ducts
The support bearer which depending on ducti tructural opening size could be either channel or angle section may be ll1ilised in any of the following arrangementsshy
a) To support the underside of a flat bar clip in halves (circular)
b) To support the underidc of either the stiffening frame oftbe flanged joint ofaoy duct section
c) To support either a stiffening frame Or a flanged joint below nsing drop rod srudding
20
DW154 Spediraiml for Plastics Ductwork
Arrangement of bearers and hangers (to be read in conjunction with Table 8 amp 9
wbich list material sizes relative 10 duel izes)
KEY Limits refer to actual duct size - insulation is additional - Typical
attachmentv -Atta hment t strucUlrcI to strucUlrc
I I
I - Flat Bar
I - Drop rod or - utlinc of lllddmg In ulillwn (if
applicable)
Alternative 7 drop rod or rt------------ 1 studdmg q I
I I Rectangular
ii i n 1
Fig 21 Rolled or profiled bearer Limit oncFig 19 Wrap-round hanger Limit 55 DIA
V v Drop rod orAllernaUC 1 1 tudding
drop rod or 1
-- -- 1studding and elded bas 1
I I0 -_
Limit 355 DIA Frg 22 Split clips Limit 1500 DIAFig 20 Flat strap hanger amp split clips
21
DW154 Specification for Plastics Ductwork
6PA deElned in J62 appropriate to the airflow pressure acoustic temperature and corrosion
General
15 ACCESSl SPECTION OPENINGS
151 General These are for inspectionservici ng on 1y
HVCA publication DWIl44 Part 7 - General Section 20 sets out the requirements for access applicable to this specification
152 Cleaningmaintenance Designers shall take specialist advice and then stipulate their requirements for the periodic internal cleaningmaintenance of ductwork and of the consequent need for adequate access for specialist cleaning equipment including the size type and locationfrequency of the actual access openings required
Appendix D sets out guidance notes for the consideration of cleaning access and also makes reference to the HVCA publication TR 17 Guide to Good Practice Cleanliness of Ventilation Systems which covers the su~ject
in greater detail
Note A majority of in tallations in which plastic ductwork is used are considered to have a nigb operational risk potential and provision of access should address this
16 REGULATI G DAMPERS
161 General Balancing dampers and control dampers are elements inserted into an air di tribution system or element of an air distribution sy middottem Balancng dampers permit modification of the air resistance of tbe system and consequently cbanging of the airflow rate Control dampers control tlle airflow rate and may in addition provide low leakage closure of the airflow
The deigner shall specify damper locations taking into consideration that good design practice requires a minimum of five times the diameter or width of the shortest side of uninterrupted flow between plant connections and the damper and select the damper type as
characteristics
1611 Balancing damper To achieve the required distribution of air in the ductwork system at inlets andor outlets for [hi purpose the damper blades are set and Jocked manually in position between fully open and fully closed
1612 Control damper To secure dynamic control of the air now in the ductwork system In thi function the damper will always be power actuated and may require to be modulated between fully open and fully closed and to be capable of taking up any position between these extremes In the fully open position the damper should have a minimum pressure drop In the fully closed position it will not necessarily achieve a complete shut off
162 Types of airflow control dampers Airflow dampers of various types are available for specific purposes as follows
1621 Single - blade dampers Single-blade dampers shall consist of a si ngle pi voted blade cOlllained withjn a casing or section of ductwork The blade shall be adjustable tbmugh a nominal 90 angle by means of a quadrant or similar operating mechanism Where automatic control of the damper is required the spindle shall be extended to enable a powered actllator to be mounted
Single-blade dampers shall have a maximum duct width of 400 nUll and a maximum duct height of 400 mm for rectangular ducts and for circular ducts a maximum diameter of 400 mm
1622 Multi-blade dampers Multi-blade dampers shall consist of a number of pivoted blades contained within a casing The blades shall be
22
DW154 Sedicalirm for Plastics Ductwork
adju table through a nominal 90deg angle simultaneously by intershyconnected linkage or gears connected to a quadrant or similar operating mecbanism Where automatic control of a damper is required a spindle shall be extended to enable a powered achlator to be mounted
There is no restriction on the size of duct in which multi-blade dampers or damper assemblie may be u ed Where dampers are required for blade lengths in excess of 750 mm the blades should be suitably reinforced or supponed 0
individual damper blade should exceed 200 mm in width
1623 Iris dampers Lris dampers shall consist of a nUlllber of radialty interconnected blades which open or close within a casing with duct COlll1cctions The blade shall be simultaneously adjusted by a quadrant or similar operating mechanism
Iris dampers shall be installed as specified by the manufacturers operating and installation instructions where the product is unidirectional with regard to airflow
lris dampers are available for circular ducts only in diameters up to 250 mm (it should be noted that the damper casin i appro)(imately twice the diameter of the duct)
1624 Backdraught dampers Air pressure operated uni-directional rectangular (single or multi-blade) with adapters if fitted to circular ducts
1625 Slide and blast gate dampers A damper [lsed as a shut off facility with an externaJ Lide bousing allowing the blade configuration to be fuJly inserted to fully extended for maxiDlUlll air flow
163 Construction
1631 Materials All products shall be protected against cOHosion as necessary and supplied in a fully finished condition as specified by the designer
1632 Dampers used in low and medium pressure systems The following recommendations apply to dampers forming an integral part of ducrwork with pressure classifications A and B air leakage limits
The dampers shaH be constructed to minimise distortion and prevent jammin in operation Th blade shall be sufficiently rigid to minimise movement when in the locked pOSitiOLl
The blades shall be securely fixed to the operating mechanism All balancing dampers shall have a locking device located on the outsid of the case and shall giv clear indication of the actlwl blad position All penetrations of the duct shall be fitted with suitable seals where necessary
1633 Dampers used in high pressure systems Regulatino- dampers used in duc[work sy tems to pressure cJassification C shall meet tbe construction requireshyments specified in 1631 and 1632 with operating mechanisms out of the air-stream
1634 Proprietary types of damper The use of any specific type of proprietary damper shall be confirmed by the designer In all cases proprietary dampers shall meet the relevant requirements of thi specification
1635 Damper casings Duct damper casings hall be constructed to meet th mllllmum
23
DW154 SpeciJimlioll for Plastics Ductwork
leakage Iim its sp cified for th c1uctwork ystem to which tbey are installed
In order to apply the square metre leakage calculatio as detailed in DW143 A Practical Guide to Ductwork Leakage Testing the reference casing area ball be taken as the perimeter ize of lh damper IDultipli d by the equi alent length of Imetr eg an 800 mm x 400 mm duct damper hall have a surface area for casillg leakag p donnan calculated as follow (2 x 08) + (2 x 04 x I
=24m2 casing area
Other pelforlllance ancl rating test methods for damp f and valves are specified in ISO 5129 and BSIE 1751 and are referenced belm a) Leakage past a closed damper
alve BSIE 1751 b) low ratepre sure requirement
characteri t cs BSIE 1751 c) Operational torque le ring
BSEN 1751 cl) Thermal transfer testing
BSIEN 17 I e) Reg nerated sound power levels
ISO 5129
164 Installation Dampers shall be imaalled in accordance will) any re Ievant ISO EN or British Standard 10 aJ bUT lcling regulation and national code of practice as well as the manufacturers recommendations
17 FIRE DAMPERS AND INT MESCENT SLEEVES
171 General Damper or sleeves arc requiTed on duct y~telll where the designer has -tjpulated the
duct wiU penetrate a fire compartment in the majority of application tbermopla ti ductwork is ugtecl where contamlDated corro ive or otherwise exceptional fumes are concerned it is preferable to use tire damp r which are externalJy mounted ie of the intmnescent operated crush typ
24
72 Fit-e rating The damper assembly should have a fUT
resi tance ratin o equal to that of the fir ban-jer it penetrate and ball be fire tested and rated to the timetemperature curv of B 476 Part 20 and 22
173 Intumescent sleeve At the time of writing this specification qualified test results were available for rectangular dampers and circular dampers up to 55 mm diamet r Manufacture have indicated that they are able t provide speci fications for other size and diameters This infonnation should be confirmed b th de igner Various type are available includino
tho e incorporating ruechanical closing plate and those operated anI by expanded iJllUme c nt media
In all ca es fire damp rs and intnmeBcen leeves shall be supplied and in taUed in
accordance with the manufacturer iJlStructioos and COSHH a essm nt
174 Other types Fire dampers of mious types are availabl for specific purpose~ ee HVCA publication DW144 The de igner should )lot (hat materials for con lt1Jction bould be uitablc for the par1icular application
ALL C SES FIRE DAMPERS AND fNT MESCENT SL _VES SHALL HE S PPLTED AND INSTALLED IN A ORDA CE WITH Tf--IE MANUshyPACTURERS STRUCTTONS AND COSHH ASSESSMENT
18 FLEXIBLEEXPANSION dOINT CONNECTIONS
181 General ploperties Tbe material u ed for flexibleexpan ion iojnt~
mu t meet the design r requirements for temperature air pressllrelfe resistance applicable to pl astic duct sy tem vibration and noi e br akout when incorporated into a jointconnection and shall comply ith lh standard of air-tigbtne specifi cl for the duct work sy tem of which it fOlms part (See Figs 23 24 5 26 27 amp 28 for typical con truclion clelai Is
DW154 SJecilimtol for Plastics Ductwork
Expansion joints
Fig23 Moulded bellows type (rectangular and circular)
Fig24
~F aiblc sleeve
__ liding sleeve
~~~~
Sleeve type (circufar)
Fig 25
AIRFLO
COnlinuou~
weld~
Flexible Iceve
PV A HOWN pp SE BACKING FLATS AS FIG 2
Sliding lee c Co1linuou
weld
Flanged sleeve (rectangular and circular)
25
DW154 Specificatiol for Plastics Ductwork
Flexible con ections
Fig 26 Flexible sleeve with clips (UPVC and PP)
--__ Flexible I eve
I
I
I CODn clioD to plant ~
Band clip
Fig27 Welded flexible sleeve (UPVC only)
Plastic)sed PVC slceve ~-- onll11uo1sly welded
onrreclion to planl ~
Fig28 Flanged flexible connection (UPVC and P )
t sp dally moulded flexible flanged connCClitlll
boil
C)nneclion to plant ~
26
DW154 Specificotiol for Plastics Ductwork
182 LOClt1tion Flexible joint are typicltllly lIsed at building expansion joint and fan inletsoutlets Any others required should be indicated on the de ign drawings Care should be taken to maintain alignment across jointsconnections
183 Length Flexible Jomts shall be kept as short as pra middottieable above a minimum eft ctive length of SO mm In no ca e shall a flexible joint exceed 250 mm in lengtb
184 Connections to rectang a ducts With flanged rectangular connections Ule tlexible material shall be held in pLace with flat pIa tic strip of not less U1an 6 mm thick ltlttached to the flanges using uitabJe fixings The more heavy weight type of fleAible mateLial may also be obtained formed into a channel ection with corners fitted to give a neat air tight j int For pigot connections the Be ible material shall b held in place with flat pIa tic trips n t less than 6 mm thick
t 85 Connections to circular ducts With tlanged circular connections the flexibl material shall be held in place with flat plastic backing strips or proprietary clip bands with screw or toggle fast ners
186 Welded flexible connections (Rectangular and Circular) Where the parent and llexibl material are from imilar ba ed products they can be joined to the duct u ing the welding method described in Section 823
19 PROTECT VE FINISHES
191 nles otherwise stated all ductwork shall be mallllfactured in mat fial as pecified in tbis specification Any special coatingpaint fmishes to be provid d by the duct work contractor sball be advisd by th de igner
20 CONNECTIONS TO BUILDING OPENINGS
201 Fanning and finishing building op nings are not the repoJlsibjlity of the duftw( rk contractor and the note that follow are for guidance purpo e only
2011 Openings in brick block or concrete walls shall have inset frames to provide a suitable means of fixing grille louver masking flanges or the tlanged ends of ductwork The illset frames shall be conslnlcted to maintain the structural int grity of the wlll and where applicable cavities shall be suitably lined
2012 Openin s in dry linino partItIons shall have inset frames a 2011
2013 Openjngs in cladding walls and roofs shall have flaoged leevesframes to provide a suitable means of fixing a 2011
2014 Horizontal and vertical opening xposed to oLltside atmo phere hall
be provided with a suitable weathering fini h at the external face especially where profiled cladding is used
2015 Timber framed op nings are not permitted In fj re compart ment barriers
202 Ductwork connections to building openings hall have a flange of suitable profile to permit practical fixing to the openillg frame In selecting the profile consideration shall be given to Tabl~s 2 and 10 in this specitication relating to duct ize and rating Gasket strip or sealant shall be ltlpplied between the tJaoge and building op ning frame
21 DISCHARGEEXHAUST TERMINAL
21 Tbese shall be vertical open ended and designed to meet and comply with current r gularions on contaminated flue The designer hall ensure that the de ign and perf rmance i suitable for its intended purpose Examples of some typical terminal designs are SbOiD in Figbull 102 10 bull 104 amp 105
27
DW154 SpedjimioTl for Plastics Ductwork
22 THERMAL INSULATION
221 The provision and application of thermal insulation to ductwork is not the responsibility of the ductwork contractor
222 Where ductwork is required to be preshyinsulated the specification should be agreed with tbe designer
223 Where the temperature of the air within the duct promotes condensation on the exterior surface of the duct and cause moisture penetration througb the thermal insulation vapour scaling may be required and in this case the most important requirement is to limit penetration of the seal
The extent of any vapour sealing of ductwork thermal insulation and the support method to be u ed must be clearly pecitled in advance by the designer
224 For detailed information on the thermal insulation of ductwork reference should be made to BS 5422 1990 which covers the specification for thermal insulation materials on pipes ductwork and equipment (in the temperature range -40degC to +700degC) and BS 5970 1992 which is a Code of Practic for Thermal Insulation of Pipework and Equipment (in the temperature range -lOOdegC to +870degC)
23 FIRE RETARDANT FINISHES ON PLAST C DUCTWORK
231 The designer should note tbat ductwork constructed to DW154 has no teted fire rating or information see Appendix C
24 REINFORCEMENT OF DUCTS WITH GRP LAMINATE
241 General Where ductwork is required in larg T izes than are covered by Tables 2 4 6 amp 7 or with the increased strength sometimes necessary for industrial use external reinforcement is normally pwvided by applicatioD of glass fibreresin laminate
GRP systems will bond satisfactorily with standard UPVC sheet but for pp it is
nece sary to use a specially prepared sheet with a glass fabric backing incorporated dOling manufactllfe
The detailed techniques of fabrication using GRP are outside the scope of this speci lcation but the following notes are offered for guidance of ductwork fabricators
242 Materials
2421 Quality The laminate is made up of polyester resin complying with BS 3532 and glass fibre complying with BS 3496 or BS 3749 The nominal ratio of resin to glass fibre should be 7030 by weight
2422 Minimum properties The laminate shall comply with the followiog mini mum pbysical properties
Tensile strength - 70 MNm Tensile modulus - 7 Gl m Flexural strength - 140 M Im Bond strength (hetween laminate and substrate Not less than 7MNm Bmcol hardnes Not le s than manufacturers specification
The GRP reinforcement educe the expansion of the parent material but the resultant stre ses arc well within rhe strength of the bond However the Iinear thermal expansion curve shown in Figs 34 amp 35 will serve as a guide
Surface resistivity electrkal propcltles and acoustical propertie are similar to the relevanl unreinforced materials The fire retarding properties of GRP may be improved by the use of specialisl laminating resin
2423 Forms available GRP Laminate should be built up from the separate materials ie resin aod glass fibre in the form of chopped
I strand mat or spray ravings
28
DW154 Spcification for Plastics Ductwork
2424 Workshop conditions Polyester resuls are sensItIve to lmperature and the workshop hould b maintained at a temperature of herween 20deg and 25degC HiOh relative humidities and damp onditions should be avoided A good rate of air change must be pro icled pJeferably by m chanical ventilation
2425 Storage of materials Resin and urin o agents shouJd be stored in dark cool condirions away from the working area and in confonnit with statutor requireshyments for tJle middottorage of flarmnable liquid Because of Ule Limited torage lif of the unmixed resin and curing a eot mal lials ~hould be ch eked before use to enLlfe that they are within the manufacturer pe ified sh If life (usually ix month from the dm of manufacrure)
Glass fi re should be stored separately und r clean dry conditions
243 Surface preparafon
2431 UPVC To achieve the specified bond strengtll the urface to which the GRP is applied mut first be thoroughly cleaned and then etched either by mechanical means or by the use of a suitable solvent
2432 pp with glass fabric backing To achieve the specified bond middottrength the fabric backing must be thoroughly impregnated Witll resin
244 Mixing the materials for use The re in 1 a three part mix compri lng base I sin hardener and accelerator The manufactur rs pecj[ied proportions are critical and th llUxmg sequenc pecified must be meticulously foUowed
The resin has a very limited life after mixing and before u e It is dependent on the characteri tics and bulk of th resin the alllount of hardener the degree and method of acceleration and the workshop onditions
245 Methods of application
2451 General The mixed resin may be applied by hand or b pray c1epoition The operation must b completed within the gel time of th y tern and tbe laminat fully cOI1olidated to achi v the phy ieal properties pecified
2452 Hand lay-up The duct surface i coated by hand with resin Llsing a brush and a mar of gla fibp orked in until full consolidation achieved Th proc is repeated untiJ th requird thicknes i obtained
2453 Spray depo Won The duct surface is coated WiUl re in by spray gun with the chopped glass roving added through a separate nozzle The full thickne i obtain d in layer with con olidation of each layer by hand roller
246 Construction
2461 General M ini mum COllst ructional requireshyments are pe itied ill Tabl 10 for rectangular and Table 1J for circular dUClS
2462 Joints and stiffeners Fig 29 30 31 32 amp 33 hoI TOSS
joint and tiffener for reinforced UPVC and PBPP duct
247 Worki g practices The fabrication of ductwork pecifiecl ill thi document i not affected by the addition of GRP
29
DW154 SfJcdJicatiOt for Plastics Ductwork
Table 10 Minimum constructional requirements shy
Longer Side Minimum Sheet Thicknes and
GRP Reinforcement
UPVC FBIPP 1 2 3
mm mm mm Up to 1000 3 plus 3 plus
06 kgm2 06 kgOIl GRP GRP
1001 to 2250 45 plus 3 plus 06 kgm 12 kgm
GRP GRP
2251 to 3000 45 plus 6 plus 12 kgm 12 kgm
GRP GRP
Cross Joints
UPVCFBPP 4
mm socket amp spigot
as Fig 30 or flanged as Fig 29
75 x 9 flange welded on both sides as Fig 29
75 x 9 tlange welded on both sides as Fig 29
rectangular GRP reinforced ducts
SlifTeners Maximum Spacing Between
JointsSljffeners UPVCIFBIPP UPVCFBPP
5 6 mm mm
75 x 9 flat 800 as Fig 31 or
50 x 50 x 5 plastic or MS inverted angle as Fig 32
or tormer as Fig 33
75 x 9 flat 600 as Fig 31 or
50 x 50 x 5 plastic or MS inverted angle as Fig 32
or former as Fig 33
75 x 9 flat 600+shyas Fig 31 or 50 x 50 x 5 plastic
or MS inverted angle as Fig 32
or former as Fig 33
Note 1 On rectangular duct up to 400 mm longer side no stiffeners are required 2 Applies to Tables 10 amp I I For COlJstructional operating temperature limits refer to Part 2 clause 5A 3 Tables 10 amp II apply to all pres ure classes up lo ]500 Pa
Table 11
Diameter
1 III
lJp to 1000
1001 to 1750
1751 to 2500
Minimum Sheet Thickness and
GRP Reinforcement
UPVC FBPP 2 3
mm mm 3 plus 3 plus
06 kgm 06 kgm GRP GRP
45 plus 3 plus 06 kgm2 18 kgm
GRP GRP
6 plus 6 plus 12 kglm2 18 kgm1
GRP GRP
Cross Joints
UPVCFBPP 4 III
socket amp spigot as Fig 30 or flaoged as Fig 29
75 x 9 flange welded on both sides as Fig 29
75 x 9 flange welded 00
both sides as Fi 29
inforced ducts
Maximum Spacing Between
JointsStiffeners UPVCIFBPP
6 mm 2400
800
600
Stiffencrs
UPVCFBPP 5
mm 50 x 9 flat as Fig 31
75 x 9 flat as Fig 31 or former as Fig 33 75 x 9 tlat as Fig 31 or t()rmer as Fi 33
ote On extruded tube tip to 600mm diameter no stiffenergt are required
30
DW154 Specificatioll for Plastics Ductwork
G - Cross joints and tiffeners
Fig 29 Flange Joint Fig32 Stiffener shy inverted angle
M artiPfCuQkbdd erttpObri) Wl111 RP tlddtlt
_- GRPloliu] lh~
Fig 30 Socket and spigot joint Fig33 Stiffener shy use of former
Fig 31 Stiffener Flat
I Pv FlPP ~ ~lmJaDUA1) d
OMrlQ rrnall 1( tQlS
25 STANDARD COMPONENT DRAWINGS AND ABBREVIATIONS
251 The illustrations in this section not only highlight where applicable geometric limjtations for the de ign and manufacture or ductwork components but also recommend
standard drawing representation terminology and abbreviations for both duetwork components and some of the more commonly used ancillaryplant items
252 Designers and surveyors should note that bills of quantities should provide a full description
3)
---
v
DW154 Spcc(fim(ml for Plastics Ductwork
Fig 34 Linear Thermal Expansion
u c 0 N ro 0)
b 0)
S
sect0
5 oS cl) 0)
~
on ~ ltl
c U
-30 -20 -10 0 10 20 30 40 50 60 70 80 90 TEMPRATURE C
~ V
-
~~c_ ~
~V
V ~
-7 ~
-- ~V ----
v
-6
+14
+12
+10
+8
+6
+4
+2
0
-2
--4
ig 35 Typical Design Stress tor UPVC and P
7
6
r shy 5E
-c E----0 4t) VJ 0)
ci5 0Jl 3
~
0)
Cl
2
1
o
UPVC
1
000
1
1
pp
- r-- shy r----- shy - t--shy I
__0
-30 -20 -10 0 10 20 30 40 50 60 70 80 90 TEMPERATURE C C
Note Figso 14 amp 35 shaded area refers to GRP reinforced duct
32
DW154 Speciicfltirm for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - REC ~NGULAR
Splilt~r Posilion W-mm pliucr
A B c 40]--QOO 1 W - -
601-1000 1 W4 Wf2 -
1001-1800 3 WI W3 W2
FIG DRAWING DETAfiS
tU]36 ATI Straight Duct with socket and spigol joint
rn [037 Straight Duct with flanged joints
[I []38 Straight Duct with flanged joints
rkJ Short Radius Bend
39 Applies to any augl and for duct up to 400 n11n wide
Minimum (I1m31 radills = 100 mm
Medium Radius Bend (a illustrated)
[kJ Applies to any angle
40 Long Radiu Bend Similar but radius = W
Throlll radius = W2 Applies to any angle
- Short Radius Bend with plitlers
I -shy -shy u co - t lt Li--_ 41 t 0 ~ I I I
~ I
L 1W
Minimum waal radius = 100 mm Splitters not required in bend angle less than 45deg
42 QJ1 Square Bend with turning vanes ij
3
DW154 SP(L~ficatioll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - RECTANGULAR
FIG DRAWl G DETADS
43
~
I v
L L Radius Tee with internal deflectors
44
~ Radiussed Twin Bend
45
Imiddot
er Swept Branch
46 U-
Sqoare Tee with Turning Vanes
47
~ f
Breeches Piece
48 0 y l Piece
34
DW154 Specificatioll for Plastics Ductwork
STANDARD COMPONENT RAWINGS - ECTANGULAR
55
54
51
50
53
52
49
FIG
~MX
RAWlNG
DmiddotMAX
EfjMAX
Minimum throat rndius = 100 mm
Rectangular shy Round Transformatioll
Eccentric Taper 225deg max in either plane Spliller are required for angles greater than 225deg and hould bi eet the angle between any side and duct centreline
DETATLS
Angled Offset
OUset Taper Splitters are required for angle greater than 22 0
and shoold bi eet the angl between any side and dUCI centrelinc
Mitred Offset
Concentrk Taper 2250 max in ither plane SpUtters are required for angle greater than 225deg and should bisect the angle between any side and duel c ntreline
Radiussed Offset
35
DW154 Splcilcuthm for Plastics Ductwork
STANDARD COMPONENT DRAWINGS ~ RECTANGU AR
Branch ducl DimCllsions widlh (W) (A)
urnl mm up lO 200 75
300 100 400 125 600 150
Ocr 600 200
FIG DRAWlNG DETAILS
56 poundplusmni~~ Rectan~lar - Flat Oval Transformation
57 [ Square Branch
58 er Angled Branch
Branch dUCI Dimensions wfdth (W) (A)
[- mm mm59 3shy Shoe Branch Up (0 200 75
--shy AIshy + 300 100
400 125
450 MAX 600 150
Over 600 200
Branch duct DimensIOn
rP X width (W) A)
60 - 1--shy _
~ mm mm
Bell Mouth Branch pto 200 75 300 100 t 400 125
600 150 Over 600 200
0=0 61 -
~ Bell Mouth
- shy T 4-5deg M x
--I 1-shy
TJ
62 X I ] I
Tele-scopic Joint I Illustrated with flangeL
X63
SBD Single Bladed Damper
36
---
DW154 Spedicatioll for Plastics Ductwork
STANDARD OMPONENT DRAWINGS - RECTANGULAR
DRAWING DETAILSFIG
64 on-Return DamperNRD shyshy
shyXbull
Multi-Leaf Damper Can be piggoted or flanged oppo cd or parallel blade
Alternative controls areshy
q p [gtshy
J HD65 Hand
~MD otori ed
PO Pneumalic
L-lt
l 13G 66 Blast Gate DamperX X
FireSmoke DampersSleeves
211r Ratinggtshy----
L_-
---
----
r----
Ir-- shy
IL- _-l
2hr
With i tallation frame
67 41 r Rating
4hr
Smoke damper SD
Intumc cent Sleeve L-d
37
DW154 Specijicutiolt for Plastics Ductwork
FIG
68
69
70
71
STANDARD COMPONET DRAWINGS shy REC ANGULAR
DRAVING DETAILS
gtshy Access Openings
AP 6 Access Panel - Rerno able
w [ ~ Access Door - Hinged
I ~le Inspection Cover
le -I reg -lt
~X X Flexible Connection
~ Drop Cheeked Radiussed Twin Bend
U Drop Cheek Bend
I
72 Air Flow SymbolX
38
DW154 Specifim[ioll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - ECTANGULAR
FIG DRAWING DETAILS
73
74
75
76
77
Q
Q
rp---t
~
V- I Ir---I
JL --11
THE ABOVE DETAILS TYPICAL PLENUM
Air Terminal Plenums
Plenum with side connection
Plenum with top connection
Cover plate with connection
Special plenum with connection
elescopic conn ction in direction of air flow
39
DW154 SpecijicotiOll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG
78
79
80
81
DRAWING
-23~---pound3-(MALE) (FEMAJE)
-t=j--_j(--d-shy
--L
~ THROAT RADI S= D AS T NDARD
e ~
THROAT Rjf)lU = D A MU)
DETAILS
Straight Duct With male and female connectors
Straight Duct With flange joint and slip joint
Bend MouldedIFormed Applies to any angle ego 30deg45deg60deg90deg Medium radius bend as illustrated Long radius similar but throat radius 0
Segmented Bend 90deg four section minjmum as illustrated
Other Angles 60deg = 3 sections 45deg = 3 sections 30deg = 2 sections
I
i
40 shy
DW154 Speciicafinll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG DRAWING DETAlLS
82 Segmented Twin Bend Radius = D2 max
May also be fabricated from tube
83 Equal Tee MouldedIFormed
84 -~ 1in Bend MouldedIFormed
85 Taper Concentric 1 0 as iUu trated Eccentric 30deg iJJcLuded angle
86 Short Taper
41
DW154 SpcUicatol1 for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG DRAWING DETAILS
87 30 max Offset
Angle Branch
Bran h dUCI Dimcnsions dia (D) lA)
Shoe Branch mm mm 88 Cl
Off rectanguJur Up 10 200 75 lOO 10 400 125
- 00 150 Over 600 200
Bl1IllCh duct DimenlOns din (D) (A
~-$a-Conical Branch mm mm
89 Also acceptable with Up 10 200 r
full conical surface 300 10
400 125
END VrE -shy 600 150 Over 600 200
90
m 75
100 12 150 200
mm Up to 200
_ 300 400
600 Over 600
iUtred Branch
Shoe Branch
J-L----U ~ Bell oulh Branch
ENDV1EW
93
92
91
42
DW154 Specificatiol for Plastics Ductwork
STANDARD OMPONENT DRAWINGS - CIRCULAR
FIG
94
DRAW G
I
~ 30deg 090deg
Breeches Piece
DETAILS
95 amp-----~ Blank End
~-----p Multi-Leaf Damper Can be piggolcd or fianged opposed or parallel blade
Alternative controls areshyri=-+- L-T~
I
---
LT~
I r- -
-+1
J HO Hand96
bMD Molori cd
PD Pneumatic
tl-shy bull
Single Bladed Damper 97 ~ saD
on-Return Damper Vertical application only 98 m~D
43
DW154 Sf1tcificatioll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG
99
100
101
102
DRAWING
$ I-
2hr
1 4hr
SD
~v I I
CO TINENTAL COWL
DETAILS
Iris Damper
Fi reS moke Dam persSleeves
2hr Ratillg
With installation frame
4br Rating
Smoke damper
Intumescent Sleeve
Access Openings
Access panel - removable
Access door shy hinged
fnspection cover
Discharge Continental Cowl
44
DW154 Sp(Cii(ltJll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
DRAWINGltIC DETAns
-
I
I
~
I I I High Velocity Discharge Terminal 103 I
I
I I
J I I 1 ~--
Offset Stack Discbarge Terminal 104 1
~ I e --(-
I
N
I
I
I~
I I Vertical Oischarge with Weather Cowl 105 I
--1--1 I
I
GAPI I
RTl AL DISC) lARGE WITH W ATIIER COWL
45
DW154 SpecUicatoll for Plastics Ductwork
STANDARD COMPONE T DRAWINGS - PLA TEQUIPMENTIMISCELLANEOU
FIG DRAWING DETAILS
106 ~~~ Rectangular Attenuator
107 ~- Circular Attenuator
108
~ Beod Attenuator
109 J ~(f) Heating Coil
110 J ftte Cooling Coil
III Jc[ Electric Heating Coil
112 X F
Humidifier
113 [H XX Axial Fan
114 ~fB1famp Noo-standard Ductwork Cross hntchillg (of any separate type) indicates by reference to a key any non DVil54 ductwork system
115 2llIIIIJIIIIIll Flexible Ductwork
46
DW154 SJeCUicll(iol1 for Plastics Ductwork
TABLE 12 - STANDARD ABBREVIAT ONS
ABBREVIATION FLL
AD Acces Door
AFF Axial Flow Fan
AHU Air Handling nit
All Aluminium
AP Acess Panel
AT Attenuator
AV Air enninal Unit
BE 81ank nd
BQ Blast ate Damper
CC Cooling Coil
CF Centrifugal Fan
CTA Cross alk Attenuator
CVU Constant Volume Unit
DP Drain Point
EEC Electric Heating Coil
El Expansion Joint
FAl Fresh Air Inlet
FA From Above
FB From Belo
fBPP Fabric Backed Polypropyl-ne Sheet
Flexle Flexible Connection
lexfD Flexible Du t
C False Ceiling CO an oil Unit
fD Fire Damper
FFL Finished Floor Level
FJ Flanged Joint
FOAM Rigid Polyurethane Self xtinguishing Foam
FOB Flat on Bottom
FOT Flat on Top
GAM Galvanised after ManufacttrJc
GRP Glass Reinforced Plastic
GSS Galvanised Sheet Steel
HC Heating oil
HD and controlled Damper
HH Hand Hole
HL High Level
HVD High Velocity Discharge
IC Inspection Cover
ID lri Damper
IFS Intumescent Fircleevc
47
DW154 Specification for Plastics Ductwork
TABLE 12 - STANDAR ABBREVIATION CONTINUED
ABBREVIATION
IU
L
tv1D
MS
NRD NTS
OBO
OE
PHD
PD
PP
PP
PRD
PVC
RFC
RSC
R
SBO
SO
S1 TST
SSL
TA
TB
TO TJ
TP
TV
TV
OS
UPVC
S
V
VAV
50 RSA
FULL
Induction Unit
Low Level
Motor controlled Damper
Mjld Steel
on Return Damper
at to cale
Opposed Blade Damper
Open End
Parallel Blade Damper
Pneumatic controlled Damper
Polypropylene
Self xtinguishing Polypropylene
Pressure Relief Damper
Polyvinyl Chloride
Rolled Form Chamlel
Rolled Steel Channel
R fUnit
Singl Blade Damper
Smoke Damper
Slip Joint
Stainl t el
tructural Slab Level
To Ab vc
To Blow
Top Down (In Direction of Flow)
Telescopic Joint
Test Point
TU111iog Vane
Top Up (In Direction of Flo )
Voles Otherwise Stated
Unpl3sticisecl Polyvinyl Chloride
Underside
Ultra Violet Light
Variable Air Volume
Rolled Steel Angle (Vith Size)
48
DW154 SJeriiflllioll for Plastics Ductwork
A2 DUCT PRESSUREAPPE DXA Ductwork con truct d to DWIl54 will bebullbullbullbullbullbullbullbullbullbullbullbullbullbull
Air Leakage From Ductwork To be read in conjunction with DW143 A practical guide to Ductwork Leakage Testing
CAUTION As highlighted ill both this docul1lenr and DW14 I lot ellough emphasis can be placed 01 the fact that except for high pressure class C the much more stringent ductwork constructional standard brolght about b the general acceptance of DW154 have irtlally negated the requirement for leakage-testing It is essential lO realise lhat except where it is mandatory this doclllllelll is nOl an endors ~lIlent of the rourine testing of ducts bllt purely a guide to outline the procedures for cononnity with the air leakage limits ill Table l Where the specified methods of assembly and
A3sealing of dlcls are u ed a vi ual inspection wil ordinarily sl~fll e for ver(iatioll of a well engineered and a ceptahfy airtight COl1strucrioll WHERE NOT MANDATORY DUCT LEAKAGE TESTING IS GENERALLY AN UNJUSTIFIED AND SUBSTANTIAL EXPENSE
A1 INTRODUCTION L akage from ducted air distribution systems is an Lmportant consideration in the design and operation of ventilatjon and air conditioning middotystems A ductviork t)ystem tbat ba limited air leakag within defiucd limits wiH cnsUft
that tile design characteristics of the sytem can be maintained It wilJ also ensure that energy and operatLonal cosb are maintained at optimum levels DucLwork constlucted and Ulstalled in accordance with DW154 should minimise a level of air leakage that it) appropriate to tll operating static air pre sur in tile system
A4However it is recouuised that tbe environment in wtJich middotystems are installed is not always conducive to achieving a predictable level of quality in term of system ajr leakage and it is therefore accepted that designer may sometimes require tlle ystem to be tested in part or in total It should be ecogni ed that the testing of duct systems add a ignificant cost to the installation and incur some extra tjm within the programme (Se 47 and 64 re mandatory te-sting)
manufactured to a structural standard that is compatible with the system operating pressure There are three classes of duct con truction to eorre pond with the three pre ure clas meations Class A Lo pressure ducts suita le for a maximum positive operating pressure of 500 Pascal and a maximum negative pressure of -500 Pascals Class B IVledium pressure ductmiddot suitable for a rnaxilnuJJl positive operafjn o pressure of 1000 Pascals and a maxllnum negative pre sure of -750 Pa cal Class C High pre sure ducts suitable for a maximum po ilive operating pressur of 2000 Pa cals and a maximum negativ pres ur of -750 Paltcals
LEAKAGE FROM DUCTWORK Leakao-e front pia tic air ducts occur at the joint~ and is therefore proportional to the total surface area orthe du twork in th system Tb level of leakage i imilarly related to tIle air pres ure in th du t system and whilst there LS n precis formula for calculating the level of air los it i generally accepted that leakage will increase in proportjon to pressure to rbe pOvver of 065 The effect of air leakage from high pressure velocit ductwork is critical tn terms of system perfomlan dege energy consumption and the risk of high frequency noise as ociated with leakage These problems are le critical with medium pressure 10 ity systems but should be con idered Low pres mevelocity ducts present the lowe~t
ri k in tenn of tbe effect of leakage on the operation of the s stern
SYSTEM LEAKAGE LOSS As there i no di ct relatLonship between th volume of air conv yed and the surface area f the ductwork sy tern required to match the building configuratmn it is difficult to express air leakage a a percentage of total air volume Similarly the operating pressure will vary throughollt lh 3 system and a leakage is related to pre me the calculations ar comple However it is generally ac epted tbat in typical good quaJjty systems the leakage from
49
DW154 Specificatioll for Plastics Ductwork
each class of duct llnd r operating condition will be io the region of CIa S A low pressure 6 Clas B medium pres un 3 Clas C high pressure 2
A5 SPECIFYING AIR LEAKAGE TESTING Re peeting both the co -t and programme implications a sociated with te ling du 1 for leakage the designer may for example indicate that a particular system is te ted as follow
a) High pressure ducts - all tested b) Medium pr ssure duets - 10 of the
ductwork shall be s eet d at random and tested
c) Low pre sure - unte ed In any case where a random te t i elected for medium pre sure ductmiddot the followin c1au~e is suggested for inclusion by the de ign r
The designer hall elect at random a maxirnwlI of 10 of the dUCl system to bt tested for air leakage The duct hall be tested af the pressure recommended in Table J3 for the assifi atiol for the ectiol1 of the ductwork that is to be tested The tests shall be carried Ollt as the work proceeds and prior to the application of thermal insulation In the event of test failure of the randomlY selected section the designer shall have The right to select two La1her e tiolls at random for resting Where succes ive failures are identified there shall be a Tight to require rhl COl11raCWr 10 apply remedial attention to the complete ductwork system Th contractor shall provide documented eviden e of the calculalions used to arrive (1
the allowable 10 I for the section to be tested and the client or his agent shall willess and sign the results of the test
able 13 Air leakage rates
Maximum leakage of duct work Static
prcssUft Low-pressure edium-prc-sure I Iigh-prebull me diJfercntial Class A Class B Class C
1 2 J 4 Pa Litres per second per quare metre of surface area 100 054 018 ZOO 084 028 300 110 037 400 132 044 500 153 051 600 058 019 700 064 021 800 069 023 900 075 025
1000 080 027 1100 1200 1300 1400 1500
029 030 032 033 035
1600 1700 1800 1900 2000
036 038 039 040 042
Note Recommend d mean test presures are highlighted iD bold type with the actual selection being left to tll test operator
50
DW154 Sfeeiieaioll for Plastics Ductwork
A9
A10
and air leakage classification for the y em under test
DESIGNERS CALCULATIONS The designer can middotaJculate with reasonable accuracy the predicted total loss from a ystem by
a) Calculating the operatin presure in each ection of the sy tern
b) Calculating the surface area of the ductwork in each correspondin pre lire s ction
c) Calulating the allowabl~ los at the operating pressure for each ection of the system (see table 13 for allowable leakage figures)
VARIABLE PRESSUR S IN SYSTEMS De igner can achieve significant co t saving by matchina operating pressures throughout the system to constmctional standard and appropriate air leakage testing eO the practice of specifying construction tandards for whole duct sy tems based on fan discharge pre sure may incur unnece sary costs on a project For example ome large sy terns ould well be classiC ed for I akage limits as follows
Plant room risers CJas C Main floor distriblltJou CIa B Low pre sure outlets Cla A
A6 SPECIAL CASES There may be ~itLlations on a project where circumstance dictate thal pecial consideration be given to containing air loss s eg a long mn of duclwork may incur a di -proportjonate level of air 10 s In ca es such as thi example the designer can specify an improved tandard of airtighmess ie 80 of alJo~able 10 s for la B Ju ts The designer sbould not specif a CIa C t sI at CIa s C pressure for a CIa s B ducl
A7 SUGG S ED RANGE OF TES ING
A8 TESTING OF PLANT ITEMS Items of inline pJant (eg Fig 106 to 115) will not normaUy be included in an air I akage test The dllctwork contractor may indud such itelllS in tbe te t jf rh quipm ot has a certificate of COnfOlnlity for Ihe pres ure clas
bull High pressure duct bull Medium pre sure ducts bull Low pre sur ducts bull Exposed extract syst ID bull Ceiling void extract
systems bull Secondary ducts from
VAV or fan coil units bull Flexjble duct bull Final connections and
branches to grille and diffusers
100 test See A5 Untested UDt sted
Untested
Untested Untested
Untested
SI
i
DW154 SJecijicafion for Plastics Ductwork
ig 116 Permitted leakage at various pressures
Leakage in litres per second per square metre duct surface area
Vgt
o ltgt 0 ltgt N
ltgt Cgt
0 0 cc
0 0
~
g =
g ~
c 0
J
ltgt 0 I
~ ] tn
ltgt ltgt
In ol
~ 0 ~ 8 ~
~
c ltgt ltgt
~ CJ
~ ~ ~ ~ 8
0shyij
~ ~ ~ t
ltgt ltgt 00
l
~
~ Q
c C
~ rshy
e ltgt
I 1
I Cgt ltgtv
c Co ~
~~ ~ 10
I
0 Cgt
fJshyq 410 ) 1 ltgt
ltgt N
~ shy ltgt ltgt
~ I 1
c
52
DW154 Specificatio for Plastics Ductwork
Example of a completed test sheet Test No
General
Name of job N~ jC43Pt(r2lef Building Repound ~(~~0
Part 1 - Physical details
a Section of duct work to be tested ~(diffPIfff~el1f3rd Floor
b Drawing Number g91~~ c ssure aSSJ L atlOn V~Jl~IRfYgtg~~lPre Cl T Class C
d Test static pressure -(9 raErq~ ~~~~-~~J~~~ ~~ ~~~~ll
Leakaoe factor 9~-tre3$ecMz I OM REFTOTABLE 13)e b bullbullbullbullbullbullbull
f Surface area of duct under test Q~tJJItetre$ CPROMCALCU TIO BELOW)bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull ampampamp bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull
g ]Vlaxi mum permitted leakage -~ (~i~~0 ~~r~~ ~~~l-~-11~ ~~~Q
Part 2 - Test particulars
a Duct static pressure reading 9QFt~q~ ~ middot~~~1 ~~
b Manufacturer and type of liow measuring d vice (-~~~cJ~Y-9Q7EYg c Range of measurement of now measuring device QtP)OQ~(e~~~0I~~~~1~I~ ~~~~~~W~
d Reading of flm measurin o device pmiddot IFROM RIO)ftscag ~
I (DERlVED [ROM CHART SUPPUED WITH RIG US 0 ud)1e Interpreted air flow leakage rate ~(~~~f~~~ (~l~~~~~~~~~~~~~~~~~I
f Duration ~~~~~norn~allY l~ lnil1Ut~~d~~~ it1~ W~ Date of test ~(lITled ut by Wltll s ed by ~ ~
(~lJ MIJLrr) (Si~rrfltJUYJ
Printed Name 1~g0f~ Printed Name ~~Y~9~ and Company 7jl~~~~~( UJd CompanY AB COII$Itallt8
Width and depth or diameter
Periphery ength Area
millimetreS millimetres metre qL1are metre
800 x 750 3100 1755 5440
600 x 650 2500 557 1193
300 x 300 1200 120 144
305 din 958 700 670
250 dia 785 450 353
TOTAL 8000
53
DW154 Specijilarion for Plastics Ductwork
pA XB
Guida ce No es For he ransport Handling and
Storage of uctwork
avoid damage to adjacent duct panels In somc ca es particularly on con acts calling f r repetitive sizes the use of timber jigs and spacers may be justified Where reduced bulk and greater protection are major factor such as consignments for export transporting ductwork in L shape sections may justify the increa ed ite as embly co ts
It is recommended that before a contract is finalised that consideration is given to the subject of site acces material handling and storage as tbcy havgt a strong influence on the cost efficiency of the overall activity of ductwOlk installation
B3 Handling To minilnise th risk of damage duct sections should be clearly identified and deliveries to site should be closely linked to the installation programme so as to avoid accumulation of
B1 Storage and Handling of Ra Material Material should be stored in suitably designed racking out of direct unJight Where possible the e racks should be metal to earth Edges of cut she t may be harp and protective gloves are advised Wearing teel toe-capped boots is recommended Most pIa tic sheet is manufactured with smootb mfaces andor is suppLied with protective coating Care must be taken to prevent accidental lippag of stacked materials Beiuoshy good electrical insulators the movement of stock unless earthed will allow the build up of stati All stock shapes are chemically stable at normal temperature Whil t some raw materials used in their manufacture may themselves pre ent a toxic hazard once incorporated into the lOck bape they no long r constitute such a hazard and no dermatitic bazard are known nor are any
unfiJied ductwork and minimise double handling It is important to recognise that ductwork panels joint and corners arc susceptible to damage and care must be taken wheu band ling such material through a site During handling individual item of duct work may be liable to light cross sectional deformation until thev become an integral pan of a completed ductwork system Whilst this may temporarily detract from its intended appearance thi deformation will not have any detrimental effect on the functionality of the finally a semblecl system Installation of duct work and asociated plant items ill illevitably involve manual handUng The responsibi Iiry of employers and employees to a ses the risk of personal injury during mallual handling operations is et out in the HS E publication L23 Guidance on Manual Handling Regulations 1992
environmental problems expected 84 Site storage
B2 fransport Large capacity vehicles with high-sided open or closed-top bodies are tlle mo t suitable for the transport of dllctwork Careful consideration should be given to the
Adequate floor space IDust be provided within tbe building for the site storage of ductvork Such storage shalt make due allowance for thc stOf(ne of ductwork in stacks such that access ~ egt
between them is of sufficient width to pennil the removal of item without interference to
unloading of transport on sit a not all siJes b n fit from the material handlino- and access facilities that exi [ in a manufacturing workshop such as crane- fork-lifts or loading bay Site handJiog facilities along with
adjoining sta ks Ductvork components should be positioned so a to avoid crushing Ductwork of small panel size may be stored horizontally however care should be exercised to ensure that tack sizes are limited 10 within
ehicular acce s restrictions may itilluence the type and ize of transport to be uWised
engtlls of ductwork should be positioned 0
the tmctural strength of the duct sections to prevent distortion of the lower sections within the stack
as to avoid crushing Lengths Witll projections such as branches and bends i1anges girths damper quadrauL should be loaded so as to
54
DW154 S1tciic(ltioll for Plastics Ductwork
85 Internal cleanliness of new ductwork The site storage of ductwork introduces the important cODsideration of maintaining the internal cleanliness of the ductwork R feren e should be made to HVCA documentshybull DWffM2 Guide to Good Practice - internal
Cleanliness of New Ductwork Installations If the above conditioDs can not be satisfied consideration should be given by tJle designer to amending the specification to include for Po t Installation Cleaning as covered by tJ1C HVCA documentshybull TRJ17 Guide to Good Practic - Cleanliness
of Ventilation Systems
APPE DIXC
Fi e Retardant inishes C1 Improvement in the fire retardancy of plastic
ducts can be achieved to varying degrees and is wholly dependent llPOll the surface coating laminating resin selected and construction specification adopted In some instances smoke emission is coILSidered equaUy with other speci fication requirernen ts of the materials resistance to ignition and bumjng It is therefore important for design rs to establ ish the clients and officers detailed requirements and not rely on a tbird party interpretation of fire resisting or fire retardant Where possible the specification should refer dir etly to compliance with a British or European Standard identifying the specific sections applicable There are various types of resin and mat rcLnforcements that can achieve a Class 1 surface spread of flame ratin o when tested according to BS476 Part 7 (1987) This test puts materials illto Class I - 4 in descending order of perfoDllance according to the rat and extent of flame spread over their surfac under standard beating conditions Materials should also be tested for flre propagarion to BS476 Part 6 (1989) Tbi tesr measures the amount and rate of heat evolved by the material when subjected to standard heating
conditions Test results are given as an index of Perfonnance (i) whicb is based on three sub indices (iJ (i1) (h) The higher the value of the Index of Performance (i) the greater is the material s contribution to fire growth The higher the value of the sub-index 0) rhe greater the ease of ignition aod flame spread The highest product performance classification as defined in Approved Document B of the Building Regulations is Class O This is acLlieved if a material surface of a composite ploduct i~ either a) composed throughout of materials of
limited combustibility or b) a Class I material which has a tlre
propagation index (i) of not more than 12 and sub-index (i l ) of nor more than 6
01 J Class 0 is not a cla$sif1cation identified in any British Standard test
There are resin system reported to be classified to Class O when tested to BS476 Pcl1S 6 and 7 however designers need to ensure that such sysrems can be applied to their proposed design In propriety resinmat system available the fabrication techniques and COITect application are critical to the integrity of the reinforcing and clas ificatiol1 For example in some systems the u e of a non-fire retardant gelcont on a fire retardant substrate would reduce the classification For further information see HVCA publication DW144 Appendix D
55
DW154 SplCijiClIliol1 for Plastics Ductwork
x Guidance otes For nspectmiddoton Servicing a d
Clean-ng Access Openings
D1 GE ERAL This appendix highlight in ummary fOI111
the acce considerations that hould be made by the design r iD terms of inspection servicing and cleaning Having considered the seop and the design of the dUCI work system relative to the guidelines outlined below the designer should clearly indicate which levels of acces should be incorporated into the manufacture of a new duct work system (See Table 14 and Note I b low it
D2 DESIGN CONSIDERATIONS
D21 In ptction and servicing requireshyments are set out in Section 15 of Lhis specification
D22 Cleaning requirements are set out in the HVCA pubUcation TRl7 Guide to Good Practice Clean Lines of Ventilation Systems and the guide tates The precise location ize and
type of access would be dependent on the type of ductwork cleaning inspection and te ting metbods to b adopted Care protection and standards of cleanliness prior LO cOlllmisionin o
are set out in th AV A publication DWITM2 Guide to Good Practice Internal Cleanliness of New Ductwork Installations and th guide state Wh re specific limits of cleanliness are required ductwork sball be cleaned after installation by a spcialist cleaning contractor It will b in the interests of tht desioner botb financially and practically to cunsider employing a specialist c1eauing contractor at tbe
outset of a contract to internally clean newly installed ductwork prior to bandover This approach would reali e the following benefit shyi) Tb actual numb r of cleaning
access panels could be detennined to suit the method of cleaning to be adopted (This may be 1 s than the maximum requiremen listed under Lev 13 of Table 14)
ii) Clear directions could b given to the ductwork contractor as to tJle size and location of cleaning access panels that are required to be fitted during the mauushyfaclunng pro s
iii) The specialist cleaning operation prior to commi ioning vould enable the cleaning contractor to verify the practical acee requirement for the future cleaning operation associated -vitb a regular maintenance programme
iv) A specialist cleaning operation prior to commissioning would allow the designer to omit from the speeilicatiolJ the DWrrM2 requirem nt for factory sealing protection wipe downs and capping-off
v) Specialist Ieall ill 0 to the measurable standard defin d in TR17 will allow an objective definition of cleanline to be achieved
Car ful consideration must be gIven by the designer to the practl aJ problems associated witb the manufacture and fitting of suitably si Led access panel on small cross section duct and on the circular faces of rouod and flat oval ducts in particular
D23 Special con ideration must be given by the de igner to the practical problems associated with gaining personnel access to heavily congested ceiling areas and multi-la red du twork systems This approach would avoid
56
DW154 Spfciication for Plastics Ductwork
the possibility of access panels being D3 ACCESS 0 IN-LINE EQUIPMENT incorporated into a ductwork system at the This appendix unly covers acc il1spection manufacturing stage that were later found in through the ductwork body adjacent to an item practice to be inaccessible for either ervicing of in-line equipment and not openings in the or cleaning activities equipment itself
able 14 Acce requirements for inspection servicing and cleaning
HVCA PUBLICATIO REFE NeE (uidtgt 10 Gund Prartict
Adjace t OW144 Cleanliness orVcnlillltio S~lcr~ fRjJ7
in-line LeyeJ 1 Level 2 Level 3 ite sequipment pcdionSen lcin~ Section d C1eaniJl( SUn(O)lnspc lion Palle ltk~m_n
2011 (minimum OiL Jubje-ct to duct ~zel (ft~ -Panels
Control Da pcrs One (inspection) 203 One 300 mm x 200 mm Both sid Fire Dampers One (sCTjdJl~) 20211 One 300 0101 x 200 mm One side HeatingCooling Coils One (inspedion) 20213 One 300 mm x 200 mm (lIpstream) Both sides Attenuators (rectangular) None required One 300 mm x 200 mm (downstream) Both sides Attenuators (circular) one retluired One 300 mm x 200 mm (downstream) One side Filter Sections One (inspection) 20212 one required Uoth sides Air Turn Vanes None requjred None required Both sides Changes of Direction None required one required One side In-Duct FansDevices One (inspection) 20213 None required Both sides l
1 In the absence of any indication by the designer only Level ) access will be jncorporated into a new ductwork system
2 Tbe panel izes associated with Lev lis I and 3 acee s ar e middottablished by reference to Section 20 of DW144 and Section 2 ofTRll7 respectively
57
DW154 Speclfifatio for Plastics Ductwork
pA XE
B-bliography Included in this Bibliography are technical pUblications which may be of interest (0 ductwork designers fabricators and erectors and to tho e in the heating ventilatlng air conditioning industries generally nquiric should be made of the relevant organisation at the address quoted Since its publication other addresse contained within 0V154 mav have changed and some pubJicalions may have been superseded
HEATING AND VENTILATING CONTRACTORS ASSOCIATION
4 Palace Court London W2 4JG Telephone 020-7229 2488 Fax 020-7727 9268
Orders fo FlY A Publications Old Matlsion House Eamont Bridge Penrith Cumbria CA 10 2BX (Telephone 01768 864771 Fax 01768 86718) Email hvcapoblicationshvwelfarecouk DWn 44 pe ilicatiun for sheet mctal duclwork (Iow- mediulllshy
and high-pressure) 1998) DWIl4 A practical guide to dUGI ork I akage te ting
(revised 2000) DWII54 Specification for plastic~ duct rk DW171 Guide to good Practice for kitchen venlibtion system DW191 Guide to good pracuce glass fibre ductwoJk DwrrMI Acceptance cheme for new products - Redangolar cro
joint classification Guide to good pra tice - Internal cleanliness of new ductwork installations Guide to good practice for the design for the Installation of lire and smoke uampers
J 1Other puhlications
HampV safely guide 5th edition JS2 Tool box talks JS5 Weldlng Safety booklet JSI9 afety facts bo klet Fact sheets 1-24 2nd edition JS2J COSHH manual volume 1 Advice on compliance with the
regulations 1521A CO I-rH manual volume 2 Asses mcnt h ets JS23 Ri k management manual TR3 BrazinltT and bronze welding of copper pipework cUld sheet
(I 976) TR5 Welding of carbon steel pipework (1980)
TR6 Guide to Good Practice for Site Pre sure Testing of Pipework (19 0) Guide to good practice cleanliness of ventilation Ylem
CHARTERED IN TITUTlO OF BUILDING SERVICES E G EERS Delta House 222 Balham High Road London SW12 9BS rTelephone 020-8675 5211 Fax 020-8675 5449) CIBSE Guide Volume A Design Data Volume B In tallatiol1 and quipment Data Volume C Reference Data
CommlssioniJIg Codes These Codes eover the preliminary checkS eUing to work and regulation of vanous catcgories 0 plan The Codes give a guide to design implications Series A Air Distnbution Systems Series B Boiler Plant
ri s C Automatic Conlrol ystems Cr1es R Refrigerating Sy terns
Sene iN Water Distribution Systems
Technkal Memonllda TM 4 Design Notes for the Middle East TM bull Design otes for Ductwork TM 13 Minimi iog lhc Risk of egiounaires Disease
Research Reports RROI95 Ventilation system hygiene - A review of published
infomlatioo on lhe occurrence and ffects of Olltamination Rl~02J95 Air-to-air heal rec v ry RR0395 rnfluen e of HV C on smoke detectors
ATlONAL ENI [ERING SPECIFICATION LfMITED Southgatc hamber 3739 Southgate Street Winchester S023 9EH (Telephone 01962 842058 Fax 01962 R(8982) BUfLDING S RVICES RESEARCH AND [ ORMATION ASSOCIATIO Old Bracknell Lane West Bracknell Berkshire RG 12 4AH (Telephone Brackl1eU (01344) 426511 Fax 01344 487 -7 )
Application Guides AGln4 De tglJing Vana~le Volume middotylans for KOOnl
iir Movement AG1I91 Commissioning of V Sylcms in Buildings 11 6194 Fire Dampers
B) 94 cntiJalion or KitcneTls
AG389 The Commls ionin of Air Systems In Buildmgs AH2192 Commissioning of Bern - A ~ode of Practice TN2417 I Fire Dampec il) Ventilating Ducl
BEATING VENTILATING A AIR CONDITION G MA UFACTURERS ASSOCIATIO (HEVAC) HEVAC Henley Road Medmenham Marlow Buck SU 2ER (Telephone 01491 578674 ox 01491 575024 Emoimiddot infofetacouk)
Publicatjons Air Diffusion Guide Guide to Air Handling Unit Leakage Testing Guide to Good Practice Air Handling Unit Real Room Acoustic ~ st Procedure Specification for the ertiiicatioll ofAir Filters Method of Test for Water Rejection PerfOnTlatce of Louvrcs Subjected 1(1
Simulated Rainfall Test Procedure for Acoustic Loo cs Specification 10 Floor GrilJes - Types Performan e and Method ofTest Specification for the Determination of the Collection Efficiency of SilJ1d
Trap Louvre Domestic Mechwlical Vclltllalion Systems with Heal Recovery Fan Application Guid
~an and Ouctwork Installation Guide Guide to Fan Noise and Vibration
pecification of Requirements for JallJral Smoke and Heal Exhausl Ventilators
pecification for Powered Smoke and Heat Exhaust Ventilators
Specification of Requirements for Smoke Curtains Design Gujue of Smoke Ventilation for Single Storey Lodustrilll Building~
Including those with Mezzanine Floor and IIi Racked Storage Warehou es - Issue 3
Guidance for the Design of Smoke entilation YSlem for Covered and Undergrollnd Car Parks - lssue 1
Application of SOloke Control Equipment and Syst m Guid to Good Practice - Isue J
58
DW154 Sp(C~tiifitiol for Plastics Ductwork
BRITISH STANDARDS INSTIT TION Sales Department 101 P ntooviLle Road London NI 9ND (felephone 020-78 1 78801)
CP 413 1973 Ducts for building ervices
SS 476 Fire tes on building matenals and lruc(ure
Part 4 19 4 Non-combustibility lest or materials
Part 6 I Fire propagation lest for materials
Part 7 1993 Surface spread of tlarnJ tesls for materia
Part 20 1987 Fir resistance of elements of construction
Part 21 1987 Fire r sistlUlce of loadbeanng elements of construction
Part 22 1987 Fhe istallceofllon-loadbearing elemcllts ofconsttuclion Part 23 1987 Contribution of componcnts to the fire resistance 0 a
structure
Part 24t987 Fire resi lance of wl1lilation ductl
SS 5588 nan 919 0 Fire Precautions III thc desIgn and OOSlnJ lion of buildings
S 729 1971 Hot dip galvanized oatiugs (or irOIl aod stcel articles
BS 1449 Steel plate sheet and Irip
Pan 11991 Carbon steel plate heel and strip Part 2 1983 Stainless steel plate sheer and strip
and
B middotENJOI49-2 996 BSEN 10149- 1991)
BSEN 10131 1992
BSEN22063 Sprayed metal coarings 1994 Protection of iron and steel by aluminium and zinc against
atmospheric cOlosion Irotectiotl of iron and ste I against corro ion and oxishydation at elevared temperatures
BS 353 1981 Glossary of lerms relnting to thermal insulation
BS ISO 1479 Self-tapplngscrewsandmetallicdri c crew
B -lSO 7049
1994
B 4800 1989 Painl colour for building purposes B 4848 l0 rolled structural steel sections
Part4 1972 Equal and unequal angles BS 5422 1990 Specification for the use of therm illuating matcriulS
SS 5720 1979 ode of practice for mechanical veutilating and air C 11shy
dirionin bull in building
l3S PR 12814-1 Bend resting for plasric welds
SS PR 12814-2 Tensile testing for plastic welds
SS PR 13067 Appro altesting for plastic welds
BS PR EN I 100-] Vi ual in pection ofplaslic welds
SHEET METAL AND AIR CONDITIONING CONTR-CTORS NATIONAL ASSOCIATION INC (SMACNA) Headquarters 420 I Lafayeue Center Drive Chanlilly Virginia 2051-1209
Mailing Address pa Box 221230 Cbantilly Virginilt120 153-1230
Telephone (703) 803-2980 Fax (703) 803-3732
Accepted IJJdustry Pl3Gtice for Industrial Duct Constnlelion 197 ) i-rchitecmral Sheet kwl Manual ([993)
Comractors Guide lor Modification 10 ooslruerion Colllraets 1993 Ducted Eleclric Heat Guide for ir Handling Ssrerns (1994)
En~rgy ollservatioD Guidelines (1984) Energy Recovery Equipment yslClllS (199l
Fibrou GIns Duct onS1ntClion Standards (1992)
Fire Smoke amp Radiation Damper In tall Guide for HVA Syst ms (1992) Guide t leel Stack 1(95)
HVA Air Duct Leakage Test Manual (19 ) HVA COlllmissioning lvlanual (1994)
H A Duct Construction Standards-Metal amp Flexible (1995) Addendum 01 (Nov 1997)
HVA Duct Systems Inspection Guide (1989)
HVA ySlems-Application (1986) nVAC ByternS-DLlct D ign (1990)
HVi Systems-Testing Adjusting amp Balancing (1993)
indoor Air Quality Manual (1993) tcheu quipment Fabrication Guidelmes (1990)
Managers Guide for elding (1993)
Rectangular Industrial Duct Cons1TUction Standards (19 0) Round Industrial Duct oustmction Standards (1977)
Sei mic Restraint Manual (1991) (wl Appendix E 1993) SMACNA Ma le Index ()fTechnical Publications (1995) Tbennoplnstic Duct CPY ) Construction Manual 1994)
DEPARTME OF THE ENVIRO MENT (Publications Centre) H Stationery Oflice 5 Nine Elms Lane London SWS 5DR
MampEJ 011972 Electrical in tallat1011 in buildings ( ew Editiou)
IampE 0319 Healing hot and cold wat r steam and gas losla1lations for buildings
M amp - No4 1970 Central heating and hot and cold ~ ateT in tallations for
dwelling
M amp ENo100 1971 Mechanical ventilation for building~
ASSOCIATION FOR SPECIALIST FIRE PROTECTlO As ociation House 235 Ash Road AJdershot Hampshire GUl2 4DD
Telephone OJ25221322 Fax 0 J252 333901
lublicalioos Fire Ratcd and moke Outlet Ducrwork An Industry Guide t Design and InSlalla lioll
HEALTH AND SAFETY EXEC TIVE Rose Court 2 Southwark Bridge London SEl 9HS Telephone 020-7717 6000
TWJ THE WELD G TlTUTE Abington Hall Abington Cambridge CB16AL Telepbone 0 J223 89162
Publication DatJ Oil w~ldll1g of lhermopla lics
59
DW154 wciiwlioll for Plastics Ductwork
A -=--DIX
Factors
Specific gravity shy pp = 091 approx UPVC = 14 approx
Some miscellaneous conversion factors
To convert
Length Inches to millimetres Feet to metres
Multiply by
2540 03048
To convert
Millimetres to inches Metres to feet
vIultiply by
003937 3281
Area Square inches to square millimetres 6452 Square millimetres to square inches 000155 Square feet to square metres 00929 Square metres to square feet 10764
Volume Cubic feet to cubic metres Cubic feet to litres Gallons (UK) to litres
002832 2831 4546
Cubic metres to cubic feet Litres to cubic feet Litres to gallons (UK)
35315 00353
022
Mass Ounces to grams Pounds to kiJograms Tons to tonnes
2835 04536
1016
Grams to ounces Kilograms to pounds Tonnes to tons
003527 2205
09842
Volume flow Cubic feet per minute to cubic Cubic metres per second to cubic
metres per second 0000472 feet per minute 2119 Cubic feet per mIDute to litres Litres per second to cubic feet
per second 04719 per minute 2119
Motion Feet per minute to metres per second 000508 Metres per second to feet per minute 197
Pressure Inches water gauge to millibars 2491 Inches wateJ- gauge to pascals (Pa) 2491 I Pa = I ewton per square metre = 10-2 millibars
60
Heating and Ventilating Contractors Association Esca House 34 Palace Court London W2 4JG
Tel 020 7313 4900
e-mail contact Itvcaorguk web site wwwhvcaorguk
Fax 020 7727 9268
DW154 Specifiiutiofl for Plastics Ductwork
Table 6 constructional quiremen s - circular unshy inforced U VC
Diameter Minimum Joints Stiffeners Maximum spa ~in r
Sheet between Thickness Jointsl tiffcners
1000 Pa 1500 Pa
1 2 3 4 5 6 UD mm mm mm mm
UO to 600 3 socket amp spigot as Figs 10 11
or fla ged Fig 12
601 to 1000 45 socket amp spigot 50 x 9 flat 2400 2400 as Figs 10 11 welded bo sides
or Oanged as Fig 13 as Fig 12
1001 to 1500 6 Hanged 75 x 9 flat 1200 1200 as Fig 2 welded both ides
as Fig 13
Applies 10 Tables 6 alld 7
Note 1 For constructional operating temperature limit refer to Part 2 luu 54 2 To allow for conicleration or extruded se lions or fabricated component the materia] tllicknes i hawn a nominal
Table 7 Minimu onstrucfional requirements shy circular un-reinforced PPS and
Diameter Minimum Joints Stiffcners Maximum pacio Sheet between
Thickness Join sStiffener 1000 Pa 150n Pa
I 2 3 4 6 mm m m mm
110 to 500 3 socket amp spigot as Fig 10 or flaoged as Fig 12
501 to 750 45 ocket amp spi~ot
as Fi 10 or Uanged as Fig 12
751 to 1000 6 tlanged 50 x 9 Oat UOO 12 0 as Fig 12 welded nth sides
as Fig 13 1 1 to 1250 6 flanged 75 x 9 flat 800shy 800
as Fig 12 welded both sides as Fig 13
1251to~ flangcd 75 x 9 Oat 600 600 as Fig 12 welded both sides
as Fig 13
18
DW154 Sped(icalirm for Plastics Ductwork
PARTS
Hangers an Suppo ts
14 GENERA
141 Supports are an e sentiaJ part of me ductwork system and their supply and in tallation are normally the responsibility of the ductwork contractor The principl s are a I-rvCA publication DWIl44 Part 6 Section 19 and should be read in conjunction with this document
Design Note Designers may pecify specific requirements wbich will supersede guidance given in DW144
142 Rectangular ducts abl 8 give the- minimum requirements for
hanger and supports for un-reinforced ductwork
143 Circular ducts Table 9 gives the minimum requirements for hangers and upports for uD-reinforced ductwork
144 Vertical d cts The design of supports for vertical duct is dictated by site condition and where practical duc hould be upported at 4000 mm interval or where tbey pa s through a floor (but n ver exceeding 4500 mm) see Figs 17 amp J8
145 External ducts Where ducts are external to buildings and may be ubject to wind loading support should be plac d so as to restrain ide tl1ruSt and should allow axial movement as neces ary It is the respon ibility of me de igner to calculate the effect of the particular prevailing condition and to define any special upport requirement
146 Expansion joints Support shall be designed to permit axial movement only and shall e provided on eitl1er ide of expansion joint
I 1shy
I~
mm -Jp to 400
401 to 600 601 to 1000
Table B Hangers and Supports - rectangular horizontal ducts
Hanger Bearer Drop Roll Formed Rod
Long r Side
Cbannel ~-shy ~
---shy
Maximum ~pacing
4 52 3 _ -c Fig 15 - Figs 14 15 16 amp 2J
shy
mmm mmmm 240025 x 25 x 16 40 x 20 x 15 8 240040x20x15 40x 20 x 15 10 240040 x 20 x 1~510 40 x 20 x 15
shy
I
40 x 40 x 15 40 x 40 x 15 24001001 to 1500 I 10
Table 9 Hangers and Supports - circular horizontal ducts
Longer Side Hanoer Split Clips Maximum spacing Drop Roll f-ormed and Wrap-round Rod ~hannel Hang r
2 3 4I Fig 1920 amp 22Fig I
mm mmmm mm mm 25 x 25 x 15 IIp to 355 8 40 x 3- --1-_ 2400
2400
2400 2400
70x 6
40 x 5 SOx 5
40 x 20 x 15 40 x 20 x 15 40 x 40 15
10 10 10
356 to 600 601 to 1000 1001 to 1500
19
DW154 Spccijicutioll for Plastics Ductwork
147 Protection specification Any special coatingpaint Unless otherwise stated all support shall be finishes for protection against hostile manufactured in material as specified in this environments shall be advised by the designer
SUPPORT BEARERS
~ 14 Flg16 Inverted profile
angle I ~lIed steel
channel (alternatives) Fig 15 Profile channel (alternatives)
TYPICmiddotAL VERTICAL DUCT SUPPORTS Flat bar clipStiffening frame Outline ofinsulation stiffening frame or tlanged joint (if applicable) or flanged joint
Stiffening framc or flanged Joint
~~-I ( ee notes 10) I
r--~ -++- ~--4==J===4~---
Fig 17 Vertical rectangular ducts Fig18 Vertical circular ducts
The support bearer which depending on ducti tructural opening size could be either channel or angle section may be ll1ilised in any of the following arrangementsshy
a) To support the underside of a flat bar clip in halves (circular)
b) To support the underidc of either the stiffening frame oftbe flanged joint ofaoy duct section
c) To support either a stiffening frame Or a flanged joint below nsing drop rod srudding
20
DW154 Spediraiml for Plastics Ductwork
Arrangement of bearers and hangers (to be read in conjunction with Table 8 amp 9
wbich list material sizes relative 10 duel izes)
KEY Limits refer to actual duct size - insulation is additional - Typical
attachmentv -Atta hment t strucUlrcI to strucUlrc
I I
I - Flat Bar
I - Drop rod or - utlinc of lllddmg In ulillwn (if
applicable)
Alternative 7 drop rod or rt------------ 1 studdmg q I
I I Rectangular
ii i n 1
Fig 21 Rolled or profiled bearer Limit oncFig 19 Wrap-round hanger Limit 55 DIA
V v Drop rod orAllernaUC 1 1 tudding
drop rod or 1
-- -- 1studding and elded bas 1
I I0 -_
Limit 355 DIA Frg 22 Split clips Limit 1500 DIAFig 20 Flat strap hanger amp split clips
21
DW154 Specification for Plastics Ductwork
6PA deElned in J62 appropriate to the airflow pressure acoustic temperature and corrosion
General
15 ACCESSl SPECTION OPENINGS
151 General These are for inspectionservici ng on 1y
HVCA publication DWIl44 Part 7 - General Section 20 sets out the requirements for access applicable to this specification
152 Cleaningmaintenance Designers shall take specialist advice and then stipulate their requirements for the periodic internal cleaningmaintenance of ductwork and of the consequent need for adequate access for specialist cleaning equipment including the size type and locationfrequency of the actual access openings required
Appendix D sets out guidance notes for the consideration of cleaning access and also makes reference to the HVCA publication TR 17 Guide to Good Practice Cleanliness of Ventilation Systems which covers the su~ject
in greater detail
Note A majority of in tallations in which plastic ductwork is used are considered to have a nigb operational risk potential and provision of access should address this
16 REGULATI G DAMPERS
161 General Balancing dampers and control dampers are elements inserted into an air di tribution system or element of an air distribution sy middottem Balancng dampers permit modification of the air resistance of tbe system and consequently cbanging of the airflow rate Control dampers control tlle airflow rate and may in addition provide low leakage closure of the airflow
The deigner shall specify damper locations taking into consideration that good design practice requires a minimum of five times the diameter or width of the shortest side of uninterrupted flow between plant connections and the damper and select the damper type as
characteristics
1611 Balancing damper To achieve the required distribution of air in the ductwork system at inlets andor outlets for [hi purpose the damper blades are set and Jocked manually in position between fully open and fully closed
1612 Control damper To secure dynamic control of the air now in the ductwork system In thi function the damper will always be power actuated and may require to be modulated between fully open and fully closed and to be capable of taking up any position between these extremes In the fully open position the damper should have a minimum pressure drop In the fully closed position it will not necessarily achieve a complete shut off
162 Types of airflow control dampers Airflow dampers of various types are available for specific purposes as follows
1621 Single - blade dampers Single-blade dampers shall consist of a si ngle pi voted blade cOlllained withjn a casing or section of ductwork The blade shall be adjustable tbmugh a nominal 90 angle by means of a quadrant or similar operating mechanism Where automatic control of the damper is required the spindle shall be extended to enable a powered actllator to be mounted
Single-blade dampers shall have a maximum duct width of 400 nUll and a maximum duct height of 400 mm for rectangular ducts and for circular ducts a maximum diameter of 400 mm
1622 Multi-blade dampers Multi-blade dampers shall consist of a number of pivoted blades contained within a casing The blades shall be
22
DW154 Sedicalirm for Plastics Ductwork
adju table through a nominal 90deg angle simultaneously by intershyconnected linkage or gears connected to a quadrant or similar operating mecbanism Where automatic control of a damper is required a spindle shall be extended to enable a powered achlator to be mounted
There is no restriction on the size of duct in which multi-blade dampers or damper assemblie may be u ed Where dampers are required for blade lengths in excess of 750 mm the blades should be suitably reinforced or supponed 0
individual damper blade should exceed 200 mm in width
1623 Iris dampers Lris dampers shall consist of a nUlllber of radialty interconnected blades which open or close within a casing with duct COlll1cctions The blade shall be simultaneously adjusted by a quadrant or similar operating mechanism
Iris dampers shall be installed as specified by the manufacturers operating and installation instructions where the product is unidirectional with regard to airflow
lris dampers are available for circular ducts only in diameters up to 250 mm (it should be noted that the damper casin i appro)(imately twice the diameter of the duct)
1624 Backdraught dampers Air pressure operated uni-directional rectangular (single or multi-blade) with adapters if fitted to circular ducts
1625 Slide and blast gate dampers A damper [lsed as a shut off facility with an externaJ Lide bousing allowing the blade configuration to be fuJly inserted to fully extended for maxiDlUlll air flow
163 Construction
1631 Materials All products shall be protected against cOHosion as necessary and supplied in a fully finished condition as specified by the designer
1632 Dampers used in low and medium pressure systems The following recommendations apply to dampers forming an integral part of ducrwork with pressure classifications A and B air leakage limits
The dampers shaH be constructed to minimise distortion and prevent jammin in operation Th blade shall be sufficiently rigid to minimise movement when in the locked pOSitiOLl
The blades shall be securely fixed to the operating mechanism All balancing dampers shall have a locking device located on the outsid of the case and shall giv clear indication of the actlwl blad position All penetrations of the duct shall be fitted with suitable seals where necessary
1633 Dampers used in high pressure systems Regulatino- dampers used in duc[work sy tems to pressure cJassification C shall meet tbe construction requireshyments specified in 1631 and 1632 with operating mechanisms out of the air-stream
1634 Proprietary types of damper The use of any specific type of proprietary damper shall be confirmed by the designer In all cases proprietary dampers shall meet the relevant requirements of thi specification
1635 Damper casings Duct damper casings hall be constructed to meet th mllllmum
23
DW154 SpeciJimlioll for Plastics Ductwork
leakage Iim its sp cified for th c1uctwork ystem to which tbey are installed
In order to apply the square metre leakage calculatio as detailed in DW143 A Practical Guide to Ductwork Leakage Testing the reference casing area ball be taken as the perimeter ize of lh damper IDultipli d by the equi alent length of Imetr eg an 800 mm x 400 mm duct damper hall have a surface area for casillg leakag p donnan calculated as follow (2 x 08) + (2 x 04 x I
=24m2 casing area
Other pelforlllance ancl rating test methods for damp f and valves are specified in ISO 5129 and BSIE 1751 and are referenced belm a) Leakage past a closed damper
alve BSIE 1751 b) low ratepre sure requirement
characteri t cs BSIE 1751 c) Operational torque le ring
BSEN 1751 cl) Thermal transfer testing
BSIEN 17 I e) Reg nerated sound power levels
ISO 5129
164 Installation Dampers shall be imaalled in accordance will) any re Ievant ISO EN or British Standard 10 aJ bUT lcling regulation and national code of practice as well as the manufacturers recommendations
17 FIRE DAMPERS AND INT MESCENT SLEEVES
171 General Damper or sleeves arc requiTed on duct y~telll where the designer has -tjpulated the
duct wiU penetrate a fire compartment in the majority of application tbermopla ti ductwork is ugtecl where contamlDated corro ive or otherwise exceptional fumes are concerned it is preferable to use tire damp r which are externalJy mounted ie of the intmnescent operated crush typ
24
72 Fit-e rating The damper assembly should have a fUT
resi tance ratin o equal to that of the fir ban-jer it penetrate and ball be fire tested and rated to the timetemperature curv of B 476 Part 20 and 22
173 Intumescent sleeve At the time of writing this specification qualified test results were available for rectangular dampers and circular dampers up to 55 mm diamet r Manufacture have indicated that they are able t provide speci fications for other size and diameters This infonnation should be confirmed b th de igner Various type are available includino
tho e incorporating ruechanical closing plate and those operated anI by expanded iJllUme c nt media
In all ca es fire damp rs and intnmeBcen leeves shall be supplied and in taUed in
accordance with the manufacturer iJlStructioos and COSHH a essm nt
174 Other types Fire dampers of mious types are availabl for specific purpose~ ee HVCA publication DW144 The de igner should )lot (hat materials for con lt1Jction bould be uitablc for the par1icular application
ALL C SES FIRE DAMPERS AND fNT MESCENT SL _VES SHALL HE S PPLTED AND INSTALLED IN A ORDA CE WITH Tf--IE MANUshyPACTURERS STRUCTTONS AND COSHH ASSESSMENT
18 FLEXIBLEEXPANSION dOINT CONNECTIONS
181 General ploperties Tbe material u ed for flexibleexpan ion iojnt~
mu t meet the design r requirements for temperature air pressllrelfe resistance applicable to pl astic duct sy tem vibration and noi e br akout when incorporated into a jointconnection and shall comply ith lh standard of air-tigbtne specifi cl for the duct work sy tem of which it fOlms part (See Figs 23 24 5 26 27 amp 28 for typical con truclion clelai Is
DW154 SJecilimtol for Plastics Ductwork
Expansion joints
Fig23 Moulded bellows type (rectangular and circular)
Fig24
~F aiblc sleeve
__ liding sleeve
~~~~
Sleeve type (circufar)
Fig 25
AIRFLO
COnlinuou~
weld~
Flexible Iceve
PV A HOWN pp SE BACKING FLATS AS FIG 2
Sliding lee c Co1linuou
weld
Flanged sleeve (rectangular and circular)
25
DW154 Specificatiol for Plastics Ductwork
Flexible con ections
Fig 26 Flexible sleeve with clips (UPVC and PP)
--__ Flexible I eve
I
I
I CODn clioD to plant ~
Band clip
Fig27 Welded flexible sleeve (UPVC only)
Plastic)sed PVC slceve ~-- onll11uo1sly welded
onrreclion to planl ~
Fig28 Flanged flexible connection (UPVC and P )
t sp dally moulded flexible flanged connCClitlll
boil
C)nneclion to plant ~
26
DW154 Specificotiol for Plastics Ductwork
182 LOClt1tion Flexible joint are typicltllly lIsed at building expansion joint and fan inletsoutlets Any others required should be indicated on the de ign drawings Care should be taken to maintain alignment across jointsconnections
183 Length Flexible Jomts shall be kept as short as pra middottieable above a minimum eft ctive length of SO mm In no ca e shall a flexible joint exceed 250 mm in lengtb
184 Connections to rectang a ducts With flanged rectangular connections Ule tlexible material shall be held in pLace with flat pIa tic strip of not less U1an 6 mm thick ltlttached to the flanges using uitabJe fixings The more heavy weight type of fleAible mateLial may also be obtained formed into a channel ection with corners fitted to give a neat air tight j int For pigot connections the Be ible material shall b held in place with flat pIa tic trips n t less than 6 mm thick
t 85 Connections to circular ducts With tlanged circular connections the flexibl material shall be held in place with flat plastic backing strips or proprietary clip bands with screw or toggle fast ners
186 Welded flexible connections (Rectangular and Circular) Where the parent and llexibl material are from imilar ba ed products they can be joined to the duct u ing the welding method described in Section 823
19 PROTECT VE FINISHES
191 nles otherwise stated all ductwork shall be mallllfactured in mat fial as pecified in tbis specification Any special coatingpaint fmishes to be provid d by the duct work contractor sball be advisd by th de igner
20 CONNECTIONS TO BUILDING OPENINGS
201 Fanning and finishing building op nings are not the repoJlsibjlity of the duftw( rk contractor and the note that follow are for guidance purpo e only
2011 Openings in brick block or concrete walls shall have inset frames to provide a suitable means of fixing grille louver masking flanges or the tlanged ends of ductwork The illset frames shall be conslnlcted to maintain the structural int grity of the wlll and where applicable cavities shall be suitably lined
2012 Openin s in dry linino partItIons shall have inset frames a 2011
2013 Openjngs in cladding walls and roofs shall have flaoged leevesframes to provide a suitable means of fixing a 2011
2014 Horizontal and vertical opening xposed to oLltside atmo phere hall
be provided with a suitable weathering fini h at the external face especially where profiled cladding is used
2015 Timber framed op nings are not permitted In fj re compart ment barriers
202 Ductwork connections to building openings hall have a flange of suitable profile to permit practical fixing to the openillg frame In selecting the profile consideration shall be given to Tabl~s 2 and 10 in this specitication relating to duct ize and rating Gasket strip or sealant shall be ltlpplied between the tJaoge and building op ning frame
21 DISCHARGEEXHAUST TERMINAL
21 Tbese shall be vertical open ended and designed to meet and comply with current r gularions on contaminated flue The designer hall ensure that the de ign and perf rmance i suitable for its intended purpose Examples of some typical terminal designs are SbOiD in Figbull 102 10 bull 104 amp 105
27
DW154 SpedjimioTl for Plastics Ductwork
22 THERMAL INSULATION
221 The provision and application of thermal insulation to ductwork is not the responsibility of the ductwork contractor
222 Where ductwork is required to be preshyinsulated the specification should be agreed with tbe designer
223 Where the temperature of the air within the duct promotes condensation on the exterior surface of the duct and cause moisture penetration througb the thermal insulation vapour scaling may be required and in this case the most important requirement is to limit penetration of the seal
The extent of any vapour sealing of ductwork thermal insulation and the support method to be u ed must be clearly pecitled in advance by the designer
224 For detailed information on the thermal insulation of ductwork reference should be made to BS 5422 1990 which covers the specification for thermal insulation materials on pipes ductwork and equipment (in the temperature range -40degC to +700degC) and BS 5970 1992 which is a Code of Practic for Thermal Insulation of Pipework and Equipment (in the temperature range -lOOdegC to +870degC)
23 FIRE RETARDANT FINISHES ON PLAST C DUCTWORK
231 The designer should note tbat ductwork constructed to DW154 has no teted fire rating or information see Appendix C
24 REINFORCEMENT OF DUCTS WITH GRP LAMINATE
241 General Where ductwork is required in larg T izes than are covered by Tables 2 4 6 amp 7 or with the increased strength sometimes necessary for industrial use external reinforcement is normally pwvided by applicatioD of glass fibreresin laminate
GRP systems will bond satisfactorily with standard UPVC sheet but for pp it is
nece sary to use a specially prepared sheet with a glass fabric backing incorporated dOling manufactllfe
The detailed techniques of fabrication using GRP are outside the scope of this speci lcation but the following notes are offered for guidance of ductwork fabricators
242 Materials
2421 Quality The laminate is made up of polyester resin complying with BS 3532 and glass fibre complying with BS 3496 or BS 3749 The nominal ratio of resin to glass fibre should be 7030 by weight
2422 Minimum properties The laminate shall comply with the followiog mini mum pbysical properties
Tensile strength - 70 MNm Tensile modulus - 7 Gl m Flexural strength - 140 M Im Bond strength (hetween laminate and substrate Not less than 7MNm Bmcol hardnes Not le s than manufacturers specification
The GRP reinforcement educe the expansion of the parent material but the resultant stre ses arc well within rhe strength of the bond However the Iinear thermal expansion curve shown in Figs 34 amp 35 will serve as a guide
Surface resistivity electrkal propcltles and acoustical propertie are similar to the relevanl unreinforced materials The fire retarding properties of GRP may be improved by the use of specialisl laminating resin
2423 Forms available GRP Laminate should be built up from the separate materials ie resin aod glass fibre in the form of chopped
I strand mat or spray ravings
28
DW154 Spcification for Plastics Ductwork
2424 Workshop conditions Polyester resuls are sensItIve to lmperature and the workshop hould b maintained at a temperature of herween 20deg and 25degC HiOh relative humidities and damp onditions should be avoided A good rate of air change must be pro icled pJeferably by m chanical ventilation
2425 Storage of materials Resin and urin o agents shouJd be stored in dark cool condirions away from the working area and in confonnit with statutor requireshyments for tJle middottorage of flarmnable liquid Because of Ule Limited torage lif of the unmixed resin and curing a eot mal lials ~hould be ch eked before use to enLlfe that they are within the manufacturer pe ified sh If life (usually ix month from the dm of manufacrure)
Glass fi re should be stored separately und r clean dry conditions
243 Surface preparafon
2431 UPVC To achieve the specified bond strengtll the urface to which the GRP is applied mut first be thoroughly cleaned and then etched either by mechanical means or by the use of a suitable solvent
2432 pp with glass fabric backing To achieve the specified bond middottrength the fabric backing must be thoroughly impregnated Witll resin
244 Mixing the materials for use The re in 1 a three part mix compri lng base I sin hardener and accelerator The manufactur rs pecj[ied proportions are critical and th llUxmg sequenc pecified must be meticulously foUowed
The resin has a very limited life after mixing and before u e It is dependent on the characteri tics and bulk of th resin the alllount of hardener the degree and method of acceleration and the workshop onditions
245 Methods of application
2451 General The mixed resin may be applied by hand or b pray c1epoition The operation must b completed within the gel time of th y tern and tbe laminat fully cOI1olidated to achi v the phy ieal properties pecified
2452 Hand lay-up The duct surface i coated by hand with resin Llsing a brush and a mar of gla fibp orked in until full consolidation achieved Th proc is repeated untiJ th requird thicknes i obtained
2453 Spray depo Won The duct surface is coated WiUl re in by spray gun with the chopped glass roving added through a separate nozzle The full thickne i obtain d in layer with con olidation of each layer by hand roller
246 Construction
2461 General M ini mum COllst ructional requireshyments are pe itied ill Tabl 10 for rectangular and Table 1J for circular dUClS
2462 Joints and stiffeners Fig 29 30 31 32 amp 33 hoI TOSS
joint and tiffener for reinforced UPVC and PBPP duct
247 Worki g practices The fabrication of ductwork pecifiecl ill thi document i not affected by the addition of GRP
29
DW154 SfJcdJicatiOt for Plastics Ductwork
Table 10 Minimum constructional requirements shy
Longer Side Minimum Sheet Thicknes and
GRP Reinforcement
UPVC FBIPP 1 2 3
mm mm mm Up to 1000 3 plus 3 plus
06 kgm2 06 kgOIl GRP GRP
1001 to 2250 45 plus 3 plus 06 kgm 12 kgm
GRP GRP
2251 to 3000 45 plus 6 plus 12 kgm 12 kgm
GRP GRP
Cross Joints
UPVCFBPP 4
mm socket amp spigot
as Fig 30 or flanged as Fig 29
75 x 9 flange welded on both sides as Fig 29
75 x 9 tlange welded on both sides as Fig 29
rectangular GRP reinforced ducts
SlifTeners Maximum Spacing Between
JointsSljffeners UPVCIFBIPP UPVCFBPP
5 6 mm mm
75 x 9 flat 800 as Fig 31 or
50 x 50 x 5 plastic or MS inverted angle as Fig 32
or tormer as Fig 33
75 x 9 flat 600 as Fig 31 or
50 x 50 x 5 plastic or MS inverted angle as Fig 32
or former as Fig 33
75 x 9 flat 600+shyas Fig 31 or 50 x 50 x 5 plastic
or MS inverted angle as Fig 32
or former as Fig 33
Note 1 On rectangular duct up to 400 mm longer side no stiffeners are required 2 Applies to Tables 10 amp I I For COlJstructional operating temperature limits refer to Part 2 clause 5A 3 Tables 10 amp II apply to all pres ure classes up lo ]500 Pa
Table 11
Diameter
1 III
lJp to 1000
1001 to 1750
1751 to 2500
Minimum Sheet Thickness and
GRP Reinforcement
UPVC FBPP 2 3
mm mm 3 plus 3 plus
06 kgm 06 kgm GRP GRP
45 plus 3 plus 06 kgm2 18 kgm
GRP GRP
6 plus 6 plus 12 kglm2 18 kgm1
GRP GRP
Cross Joints
UPVCFBPP 4 III
socket amp spigot as Fig 30 or flaoged as Fig 29
75 x 9 flange welded on both sides as Fig 29
75 x 9 flange welded 00
both sides as Fi 29
inforced ducts
Maximum Spacing Between
JointsStiffeners UPVCIFBPP
6 mm 2400
800
600
Stiffencrs
UPVCFBPP 5
mm 50 x 9 flat as Fig 31
75 x 9 flat as Fig 31 or former as Fig 33 75 x 9 tlat as Fig 31 or t()rmer as Fi 33
ote On extruded tube tip to 600mm diameter no stiffenergt are required
30
DW154 Specificatioll for Plastics Ductwork
G - Cross joints and tiffeners
Fig 29 Flange Joint Fig32 Stiffener shy inverted angle
M artiPfCuQkbdd erttpObri) Wl111 RP tlddtlt
_- GRPloliu] lh~
Fig 30 Socket and spigot joint Fig33 Stiffener shy use of former
Fig 31 Stiffener Flat
I Pv FlPP ~ ~lmJaDUA1) d
OMrlQ rrnall 1( tQlS
25 STANDARD COMPONENT DRAWINGS AND ABBREVIATIONS
251 The illustrations in this section not only highlight where applicable geometric limjtations for the de ign and manufacture or ductwork components but also recommend
standard drawing representation terminology and abbreviations for both duetwork components and some of the more commonly used ancillaryplant items
252 Designers and surveyors should note that bills of quantities should provide a full description
3)
---
v
DW154 Spcc(fim(ml for Plastics Ductwork
Fig 34 Linear Thermal Expansion
u c 0 N ro 0)
b 0)
S
sect0
5 oS cl) 0)
~
on ~ ltl
c U
-30 -20 -10 0 10 20 30 40 50 60 70 80 90 TEMPRATURE C
~ V
-
~~c_ ~
~V
V ~
-7 ~
-- ~V ----
v
-6
+14
+12
+10
+8
+6
+4
+2
0
-2
--4
ig 35 Typical Design Stress tor UPVC and P
7
6
r shy 5E
-c E----0 4t) VJ 0)
ci5 0Jl 3
~
0)
Cl
2
1
o
UPVC
1
000
1
1
pp
- r-- shy r----- shy - t--shy I
__0
-30 -20 -10 0 10 20 30 40 50 60 70 80 90 TEMPERATURE C C
Note Figso 14 amp 35 shaded area refers to GRP reinforced duct
32
DW154 Speciicfltirm for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - REC ~NGULAR
Splilt~r Posilion W-mm pliucr
A B c 40]--QOO 1 W - -
601-1000 1 W4 Wf2 -
1001-1800 3 WI W3 W2
FIG DRAWING DETAfiS
tU]36 ATI Straight Duct with socket and spigol joint
rn [037 Straight Duct with flanged joints
[I []38 Straight Duct with flanged joints
rkJ Short Radius Bend
39 Applies to any augl and for duct up to 400 n11n wide
Minimum (I1m31 radills = 100 mm
Medium Radius Bend (a illustrated)
[kJ Applies to any angle
40 Long Radiu Bend Similar but radius = W
Throlll radius = W2 Applies to any angle
- Short Radius Bend with plitlers
I -shy -shy u co - t lt Li--_ 41 t 0 ~ I I I
~ I
L 1W
Minimum waal radius = 100 mm Splitters not required in bend angle less than 45deg
42 QJ1 Square Bend with turning vanes ij
3
DW154 SP(L~ficatioll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - RECTANGULAR
FIG DRAWl G DETADS
43
~
I v
L L Radius Tee with internal deflectors
44
~ Radiussed Twin Bend
45
Imiddot
er Swept Branch
46 U-
Sqoare Tee with Turning Vanes
47
~ f
Breeches Piece
48 0 y l Piece
34
DW154 Specificatioll for Plastics Ductwork
STANDARD COMPONENT RAWINGS - ECTANGULAR
55
54
51
50
53
52
49
FIG
~MX
RAWlNG
DmiddotMAX
EfjMAX
Minimum throat rndius = 100 mm
Rectangular shy Round Transformatioll
Eccentric Taper 225deg max in either plane Spliller are required for angles greater than 225deg and hould bi eet the angle between any side and duct centreline
DETATLS
Angled Offset
OUset Taper Splitters are required for angle greater than 22 0
and shoold bi eet the angl between any side and dUCI centrelinc
Mitred Offset
Concentrk Taper 2250 max in ither plane SpUtters are required for angle greater than 225deg and should bisect the angle between any side and duel c ntreline
Radiussed Offset
35
DW154 Splcilcuthm for Plastics Ductwork
STANDARD COMPONENT DRAWINGS ~ RECTANGU AR
Branch ducl DimCllsions widlh (W) (A)
urnl mm up lO 200 75
300 100 400 125 600 150
Ocr 600 200
FIG DRAWlNG DETAILS
56 poundplusmni~~ Rectan~lar - Flat Oval Transformation
57 [ Square Branch
58 er Angled Branch
Branch dUCI Dimensions wfdth (W) (A)
[- mm mm59 3shy Shoe Branch Up (0 200 75
--shy AIshy + 300 100
400 125
450 MAX 600 150
Over 600 200
Branch duct DimensIOn
rP X width (W) A)
60 - 1--shy _
~ mm mm
Bell Mouth Branch pto 200 75 300 100 t 400 125
600 150 Over 600 200
0=0 61 -
~ Bell Mouth
- shy T 4-5deg M x
--I 1-shy
TJ
62 X I ] I
Tele-scopic Joint I Illustrated with flangeL
X63
SBD Single Bladed Damper
36
---
DW154 Spedicatioll for Plastics Ductwork
STANDARD OMPONENT DRAWINGS - RECTANGULAR
DRAWING DETAILSFIG
64 on-Return DamperNRD shyshy
shyXbull
Multi-Leaf Damper Can be piggoted or flanged oppo cd or parallel blade
Alternative controls areshy
q p [gtshy
J HD65 Hand
~MD otori ed
PO Pneumalic
L-lt
l 13G 66 Blast Gate DamperX X
FireSmoke DampersSleeves
211r Ratinggtshy----
L_-
---
----
r----
Ir-- shy
IL- _-l
2hr
With i tallation frame
67 41 r Rating
4hr
Smoke damper SD
Intumc cent Sleeve L-d
37
DW154 Specijicutiolt for Plastics Ductwork
FIG
68
69
70
71
STANDARD COMPONET DRAWINGS shy REC ANGULAR
DRAVING DETAILS
gtshy Access Openings
AP 6 Access Panel - Rerno able
w [ ~ Access Door - Hinged
I ~le Inspection Cover
le -I reg -lt
~X X Flexible Connection
~ Drop Cheeked Radiussed Twin Bend
U Drop Cheek Bend
I
72 Air Flow SymbolX
38
DW154 Specifim[ioll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - ECTANGULAR
FIG DRAWING DETAILS
73
74
75
76
77
Q
Q
rp---t
~
V- I Ir---I
JL --11
THE ABOVE DETAILS TYPICAL PLENUM
Air Terminal Plenums
Plenum with side connection
Plenum with top connection
Cover plate with connection
Special plenum with connection
elescopic conn ction in direction of air flow
39
DW154 SpecijicotiOll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG
78
79
80
81
DRAWING
-23~---pound3-(MALE) (FEMAJE)
-t=j--_j(--d-shy
--L
~ THROAT RADI S= D AS T NDARD
e ~
THROAT Rjf)lU = D A MU)
DETAILS
Straight Duct With male and female connectors
Straight Duct With flange joint and slip joint
Bend MouldedIFormed Applies to any angle ego 30deg45deg60deg90deg Medium radius bend as illustrated Long radius similar but throat radius 0
Segmented Bend 90deg four section minjmum as illustrated
Other Angles 60deg = 3 sections 45deg = 3 sections 30deg = 2 sections
I
i
40 shy
DW154 Speciicafinll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG DRAWING DETAlLS
82 Segmented Twin Bend Radius = D2 max
May also be fabricated from tube
83 Equal Tee MouldedIFormed
84 -~ 1in Bend MouldedIFormed
85 Taper Concentric 1 0 as iUu trated Eccentric 30deg iJJcLuded angle
86 Short Taper
41
DW154 SpcUicatol1 for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG DRAWING DETAILS
87 30 max Offset
Angle Branch
Bran h dUCI Dimcnsions dia (D) lA)
Shoe Branch mm mm 88 Cl
Off rectanguJur Up 10 200 75 lOO 10 400 125
- 00 150 Over 600 200
Bl1IllCh duct DimenlOns din (D) (A
~-$a-Conical Branch mm mm
89 Also acceptable with Up 10 200 r
full conical surface 300 10
400 125
END VrE -shy 600 150 Over 600 200
90
m 75
100 12 150 200
mm Up to 200
_ 300 400
600 Over 600
iUtred Branch
Shoe Branch
J-L----U ~ Bell oulh Branch
ENDV1EW
93
92
91
42
DW154 Specificatiol for Plastics Ductwork
STANDARD OMPONENT DRAWINGS - CIRCULAR
FIG
94
DRAW G
I
~ 30deg 090deg
Breeches Piece
DETAILS
95 amp-----~ Blank End
~-----p Multi-Leaf Damper Can be piggolcd or fianged opposed or parallel blade
Alternative controls areshyri=-+- L-T~
I
---
LT~
I r- -
-+1
J HO Hand96
bMD Molori cd
PD Pneumatic
tl-shy bull
Single Bladed Damper 97 ~ saD
on-Return Damper Vertical application only 98 m~D
43
DW154 Sf1tcificatioll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG
99
100
101
102
DRAWING
$ I-
2hr
1 4hr
SD
~v I I
CO TINENTAL COWL
DETAILS
Iris Damper
Fi reS moke Dam persSleeves
2hr Ratillg
With installation frame
4br Rating
Smoke damper
Intumescent Sleeve
Access Openings
Access panel - removable
Access door shy hinged
fnspection cover
Discharge Continental Cowl
44
DW154 Sp(Cii(ltJll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
DRAWINGltIC DETAns
-
I
I
~
I I I High Velocity Discharge Terminal 103 I
I
I I
J I I 1 ~--
Offset Stack Discbarge Terminal 104 1
~ I e --(-
I
N
I
I
I~
I I Vertical Oischarge with Weather Cowl 105 I
--1--1 I
I
GAPI I
RTl AL DISC) lARGE WITH W ATIIER COWL
45
DW154 SpecUicatoll for Plastics Ductwork
STANDARD COMPONE T DRAWINGS - PLA TEQUIPMENTIMISCELLANEOU
FIG DRAWING DETAILS
106 ~~~ Rectangular Attenuator
107 ~- Circular Attenuator
108
~ Beod Attenuator
109 J ~(f) Heating Coil
110 J ftte Cooling Coil
III Jc[ Electric Heating Coil
112 X F
Humidifier
113 [H XX Axial Fan
114 ~fB1famp Noo-standard Ductwork Cross hntchillg (of any separate type) indicates by reference to a key any non DVil54 ductwork system
115 2llIIIIJIIIIIll Flexible Ductwork
46
DW154 SJeCUicll(iol1 for Plastics Ductwork
TABLE 12 - STANDARD ABBREVIAT ONS
ABBREVIATION FLL
AD Acces Door
AFF Axial Flow Fan
AHU Air Handling nit
All Aluminium
AP Acess Panel
AT Attenuator
AV Air enninal Unit
BE 81ank nd
BQ Blast ate Damper
CC Cooling Coil
CF Centrifugal Fan
CTA Cross alk Attenuator
CVU Constant Volume Unit
DP Drain Point
EEC Electric Heating Coil
El Expansion Joint
FAl Fresh Air Inlet
FA From Above
FB From Belo
fBPP Fabric Backed Polypropyl-ne Sheet
Flexle Flexible Connection
lexfD Flexible Du t
C False Ceiling CO an oil Unit
fD Fire Damper
FFL Finished Floor Level
FJ Flanged Joint
FOAM Rigid Polyurethane Self xtinguishing Foam
FOB Flat on Bottom
FOT Flat on Top
GAM Galvanised after ManufacttrJc
GRP Glass Reinforced Plastic
GSS Galvanised Sheet Steel
HC Heating oil
HD and controlled Damper
HH Hand Hole
HL High Level
HVD High Velocity Discharge
IC Inspection Cover
ID lri Damper
IFS Intumescent Fircleevc
47
DW154 Specification for Plastics Ductwork
TABLE 12 - STANDAR ABBREVIATION CONTINUED
ABBREVIATION
IU
L
tv1D
MS
NRD NTS
OBO
OE
PHD
PD
PP
PP
PRD
PVC
RFC
RSC
R
SBO
SO
S1 TST
SSL
TA
TB
TO TJ
TP
TV
TV
OS
UPVC
S
V
VAV
50 RSA
FULL
Induction Unit
Low Level
Motor controlled Damper
Mjld Steel
on Return Damper
at to cale
Opposed Blade Damper
Open End
Parallel Blade Damper
Pneumatic controlled Damper
Polypropylene
Self xtinguishing Polypropylene
Pressure Relief Damper
Polyvinyl Chloride
Rolled Form Chamlel
Rolled Steel Channel
R fUnit
Singl Blade Damper
Smoke Damper
Slip Joint
Stainl t el
tructural Slab Level
To Ab vc
To Blow
Top Down (In Direction of Flow)
Telescopic Joint
Test Point
TU111iog Vane
Top Up (In Direction of Flo )
Voles Otherwise Stated
Unpl3sticisecl Polyvinyl Chloride
Underside
Ultra Violet Light
Variable Air Volume
Rolled Steel Angle (Vith Size)
48
DW154 SJeriiflllioll for Plastics Ductwork
A2 DUCT PRESSUREAPPE DXA Ductwork con truct d to DWIl54 will bebullbullbullbullbullbullbullbullbullbullbullbullbullbull
Air Leakage From Ductwork To be read in conjunction with DW143 A practical guide to Ductwork Leakage Testing
CAUTION As highlighted ill both this docul1lenr and DW14 I lot ellough emphasis can be placed 01 the fact that except for high pressure class C the much more stringent ductwork constructional standard brolght about b the general acceptance of DW154 have irtlally negated the requirement for leakage-testing It is essential lO realise lhat except where it is mandatory this doclllllelll is nOl an endors ~lIlent of the rourine testing of ducts bllt purely a guide to outline the procedures for cononnity with the air leakage limits ill Table l Where the specified methods of assembly and
A3sealing of dlcls are u ed a vi ual inspection wil ordinarily sl~fll e for ver(iatioll of a well engineered and a ceptahfy airtight COl1strucrioll WHERE NOT MANDATORY DUCT LEAKAGE TESTING IS GENERALLY AN UNJUSTIFIED AND SUBSTANTIAL EXPENSE
A1 INTRODUCTION L akage from ducted air distribution systems is an Lmportant consideration in the design and operation of ventilatjon and air conditioning middotystems A ductviork t)ystem tbat ba limited air leakag within defiucd limits wiH cnsUft
that tile design characteristics of the sytem can be maintained It wilJ also ensure that energy and operatLonal cosb are maintained at optimum levels DucLwork constlucted and Ulstalled in accordance with DW154 should minimise a level of air leakage that it) appropriate to tll operating static air pre sur in tile system
A4However it is recouuised that tbe environment in wtJich middotystems are installed is not always conducive to achieving a predictable level of quality in term of system ajr leakage and it is therefore accepted that designer may sometimes require tlle ystem to be tested in part or in total It should be ecogni ed that the testing of duct systems add a ignificant cost to the installation and incur some extra tjm within the programme (Se 47 and 64 re mandatory te-sting)
manufactured to a structural standard that is compatible with the system operating pressure There are three classes of duct con truction to eorre pond with the three pre ure clas meations Class A Lo pressure ducts suita le for a maximum positive operating pressure of 500 Pascal and a maximum negative pressure of -500 Pascals Class B IVledium pressure ductmiddot suitable for a rnaxilnuJJl positive operafjn o pressure of 1000 Pascals and a maxllnum negative pre sure of -750 Pa cal Class C High pre sure ducts suitable for a maximum po ilive operating pressur of 2000 Pa cals and a maximum negativ pres ur of -750 Paltcals
LEAKAGE FROM DUCTWORK Leakao-e front pia tic air ducts occur at the joint~ and is therefore proportional to the total surface area orthe du twork in th system Tb level of leakage i imilarly related to tIle air pres ure in th du t system and whilst there LS n precis formula for calculating the level of air los it i generally accepted that leakage will increase in proportjon to pressure to rbe pOvver of 065 The effect of air leakage from high pressure velocit ductwork is critical tn terms of system perfomlan dege energy consumption and the risk of high frequency noise as ociated with leakage These problems are le critical with medium pressure 10 ity systems but should be con idered Low pres mevelocity ducts present the lowe~t
ri k in tenn of tbe effect of leakage on the operation of the s stern
SYSTEM LEAKAGE LOSS As there i no di ct relatLonship between th volume of air conv yed and the surface area f the ductwork sy tern required to match the building configuratmn it is difficult to express air leakage a a percentage of total air volume Similarly the operating pressure will vary throughollt lh 3 system and a leakage is related to pre me the calculations ar comple However it is generally ac epted tbat in typical good quaJjty systems the leakage from
49
DW154 Specificatioll for Plastics Ductwork
each class of duct llnd r operating condition will be io the region of CIa S A low pressure 6 Clas B medium pres un 3 Clas C high pressure 2
A5 SPECIFYING AIR LEAKAGE TESTING Re peeting both the co -t and programme implications a sociated with te ling du 1 for leakage the designer may for example indicate that a particular system is te ted as follow
a) High pressure ducts - all tested b) Medium pr ssure duets - 10 of the
ductwork shall be s eet d at random and tested
c) Low pre sure - unte ed In any case where a random te t i elected for medium pre sure ductmiddot the followin c1au~e is suggested for inclusion by the de ign r
The designer hall elect at random a maxirnwlI of 10 of the dUCl system to bt tested for air leakage The duct hall be tested af the pressure recommended in Table J3 for the assifi atiol for the ectiol1 of the ductwork that is to be tested The tests shall be carried Ollt as the work proceeds and prior to the application of thermal insulation In the event of test failure of the randomlY selected section the designer shall have The right to select two La1her e tiolls at random for resting Where succes ive failures are identified there shall be a Tight to require rhl COl11raCWr 10 apply remedial attention to the complete ductwork system Th contractor shall provide documented eviden e of the calculalions used to arrive (1
the allowable 10 I for the section to be tested and the client or his agent shall willess and sign the results of the test
able 13 Air leakage rates
Maximum leakage of duct work Static
prcssUft Low-pressure edium-prc-sure I Iigh-prebull me diJfercntial Class A Class B Class C
1 2 J 4 Pa Litres per second per quare metre of surface area 100 054 018 ZOO 084 028 300 110 037 400 132 044 500 153 051 600 058 019 700 064 021 800 069 023 900 075 025
1000 080 027 1100 1200 1300 1400 1500
029 030 032 033 035
1600 1700 1800 1900 2000
036 038 039 040 042
Note Recommend d mean test presures are highlighted iD bold type with the actual selection being left to tll test operator
50
DW154 Sfeeiieaioll for Plastics Ductwork
A9
A10
and air leakage classification for the y em under test
DESIGNERS CALCULATIONS The designer can middotaJculate with reasonable accuracy the predicted total loss from a ystem by
a) Calculating the operatin presure in each ection of the sy tern
b) Calculating the surface area of the ductwork in each correspondin pre lire s ction
c) Calulating the allowabl~ los at the operating pressure for each ection of the system (see table 13 for allowable leakage figures)
VARIABLE PRESSUR S IN SYSTEMS De igner can achieve significant co t saving by matchina operating pressures throughout the system to constmctional standard and appropriate air leakage testing eO the practice of specifying construction tandards for whole duct sy tems based on fan discharge pre sure may incur unnece sary costs on a project For example ome large sy terns ould well be classiC ed for I akage limits as follows
Plant room risers CJas C Main floor distriblltJou CIa B Low pre sure outlets Cla A
A6 SPECIAL CASES There may be ~itLlations on a project where circumstance dictate thal pecial consideration be given to containing air loss s eg a long mn of duclwork may incur a di -proportjonate level of air 10 s In ca es such as thi example the designer can specify an improved tandard of airtighmess ie 80 of alJo~able 10 s for la B Ju ts The designer sbould not specif a CIa C t sI at CIa s C pressure for a CIa s B ducl
A7 SUGG S ED RANGE OF TES ING
A8 TESTING OF PLANT ITEMS Items of inline pJant (eg Fig 106 to 115) will not normaUy be included in an air I akage test The dllctwork contractor may indud such itelllS in tbe te t jf rh quipm ot has a certificate of COnfOlnlity for Ihe pres ure clas
bull High pressure duct bull Medium pre sure ducts bull Low pre sur ducts bull Exposed extract syst ID bull Ceiling void extract
systems bull Secondary ducts from
VAV or fan coil units bull Flexjble duct bull Final connections and
branches to grille and diffusers
100 test See A5 Untested UDt sted
Untested
Untested Untested
Untested
SI
i
DW154 SJecijicafion for Plastics Ductwork
ig 116 Permitted leakage at various pressures
Leakage in litres per second per square metre duct surface area
Vgt
o ltgt 0 ltgt N
ltgt Cgt
0 0 cc
0 0
~
g =
g ~
c 0
J
ltgt 0 I
~ ] tn
ltgt ltgt
In ol
~ 0 ~ 8 ~
~
c ltgt ltgt
~ CJ
~ ~ ~ ~ 8
0shyij
~ ~ ~ t
ltgt ltgt 00
l
~
~ Q
c C
~ rshy
e ltgt
I 1
I Cgt ltgtv
c Co ~
~~ ~ 10
I
0 Cgt
fJshyq 410 ) 1 ltgt
ltgt N
~ shy ltgt ltgt
~ I 1
c
52
DW154 Specificatio for Plastics Ductwork
Example of a completed test sheet Test No
General
Name of job N~ jC43Pt(r2lef Building Repound ~(~~0
Part 1 - Physical details
a Section of duct work to be tested ~(diffPIfff~el1f3rd Floor
b Drawing Number g91~~ c ssure aSSJ L atlOn V~Jl~IRfYgtg~~lPre Cl T Class C
d Test static pressure -(9 raErq~ ~~~~-~~J~~~ ~~ ~~~~ll
Leakaoe factor 9~-tre3$ecMz I OM REFTOTABLE 13)e b bullbullbullbullbullbullbull
f Surface area of duct under test Q~tJJItetre$ CPROMCALCU TIO BELOW)bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull ampampamp bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull
g ]Vlaxi mum permitted leakage -~ (~i~~0 ~~r~~ ~~~l-~-11~ ~~~Q
Part 2 - Test particulars
a Duct static pressure reading 9QFt~q~ ~ middot~~~1 ~~
b Manufacturer and type of liow measuring d vice (-~~~cJ~Y-9Q7EYg c Range of measurement of now measuring device QtP)OQ~(e~~~0I~~~~1~I~ ~~~~~~W~
d Reading of flm measurin o device pmiddot IFROM RIO)ftscag ~
I (DERlVED [ROM CHART SUPPUED WITH RIG US 0 ud)1e Interpreted air flow leakage rate ~(~~~f~~~ (~l~~~~~~~~~~~~~~~~~I
f Duration ~~~~~norn~allY l~ lnil1Ut~~d~~~ it1~ W~ Date of test ~(lITled ut by Wltll s ed by ~ ~
(~lJ MIJLrr) (Si~rrfltJUYJ
Printed Name 1~g0f~ Printed Name ~~Y~9~ and Company 7jl~~~~~( UJd CompanY AB COII$Itallt8
Width and depth or diameter
Periphery ength Area
millimetreS millimetres metre qL1are metre
800 x 750 3100 1755 5440
600 x 650 2500 557 1193
300 x 300 1200 120 144
305 din 958 700 670
250 dia 785 450 353
TOTAL 8000
53
DW154 Specijilarion for Plastics Ductwork
pA XB
Guida ce No es For he ransport Handling and
Storage of uctwork
avoid damage to adjacent duct panels In somc ca es particularly on con acts calling f r repetitive sizes the use of timber jigs and spacers may be justified Where reduced bulk and greater protection are major factor such as consignments for export transporting ductwork in L shape sections may justify the increa ed ite as embly co ts
It is recommended that before a contract is finalised that consideration is given to the subject of site acces material handling and storage as tbcy havgt a strong influence on the cost efficiency of the overall activity of ductwOlk installation
B3 Handling To minilnise th risk of damage duct sections should be clearly identified and deliveries to site should be closely linked to the installation programme so as to avoid accumulation of
B1 Storage and Handling of Ra Material Material should be stored in suitably designed racking out of direct unJight Where possible the e racks should be metal to earth Edges of cut she t may be harp and protective gloves are advised Wearing teel toe-capped boots is recommended Most pIa tic sheet is manufactured with smootb mfaces andor is suppLied with protective coating Care must be taken to prevent accidental lippag of stacked materials Beiuoshy good electrical insulators the movement of stock unless earthed will allow the build up of stati All stock shapes are chemically stable at normal temperature Whil t some raw materials used in their manufacture may themselves pre ent a toxic hazard once incorporated into the lOck bape they no long r constitute such a hazard and no dermatitic bazard are known nor are any
unfiJied ductwork and minimise double handling It is important to recognise that ductwork panels joint and corners arc susceptible to damage and care must be taken wheu band ling such material through a site During handling individual item of duct work may be liable to light cross sectional deformation until thev become an integral pan of a completed ductwork system Whilst this may temporarily detract from its intended appearance thi deformation will not have any detrimental effect on the functionality of the finally a semblecl system Installation of duct work and asociated plant items ill illevitably involve manual handUng The responsibi Iiry of employers and employees to a ses the risk of personal injury during mallual handling operations is et out in the HS E publication L23 Guidance on Manual Handling Regulations 1992
environmental problems expected 84 Site storage
B2 fransport Large capacity vehicles with high-sided open or closed-top bodies are tlle mo t suitable for the transport of dllctwork Careful consideration should be given to the
Adequate floor space IDust be provided within tbe building for the site storage of ductvork Such storage shalt make due allowance for thc stOf(ne of ductwork in stacks such that access ~ egt
between them is of sufficient width to pennil the removal of item without interference to
unloading of transport on sit a not all siJes b n fit from the material handlino- and access facilities that exi [ in a manufacturing workshop such as crane- fork-lifts or loading bay Site handJiog facilities along with
adjoining sta ks Ductvork components should be positioned so a to avoid crushing Ductwork of small panel size may be stored horizontally however care should be exercised to ensure that tack sizes are limited 10 within
ehicular acce s restrictions may itilluence the type and ize of transport to be uWised
engtlls of ductwork should be positioned 0
the tmctural strength of the duct sections to prevent distortion of the lower sections within the stack
as to avoid crushing Lengths Witll projections such as branches and bends i1anges girths damper quadrauL should be loaded so as to
54
DW154 S1tciic(ltioll for Plastics Ductwork
85 Internal cleanliness of new ductwork The site storage of ductwork introduces the important cODsideration of maintaining the internal cleanliness of the ductwork R feren e should be made to HVCA documentshybull DWffM2 Guide to Good Practice - internal
Cleanliness of New Ductwork Installations If the above conditioDs can not be satisfied consideration should be given by tJle designer to amending the specification to include for Po t Installation Cleaning as covered by tJ1C HVCA documentshybull TRJ17 Guide to Good Practic - Cleanliness
of Ventilation Systems
APPE DIXC
Fi e Retardant inishes C1 Improvement in the fire retardancy of plastic
ducts can be achieved to varying degrees and is wholly dependent llPOll the surface coating laminating resin selected and construction specification adopted In some instances smoke emission is coILSidered equaUy with other speci fication requirernen ts of the materials resistance to ignition and bumjng It is therefore important for design rs to establ ish the clients and officers detailed requirements and not rely on a tbird party interpretation of fire resisting or fire retardant Where possible the specification should refer dir etly to compliance with a British or European Standard identifying the specific sections applicable There are various types of resin and mat rcLnforcements that can achieve a Class 1 surface spread of flame ratin o when tested according to BS476 Part 7 (1987) This test puts materials illto Class I - 4 in descending order of perfoDllance according to the rat and extent of flame spread over their surfac under standard beating conditions Materials should also be tested for flre propagarion to BS476 Part 6 (1989) Tbi tesr measures the amount and rate of heat evolved by the material when subjected to standard heating
conditions Test results are given as an index of Perfonnance (i) whicb is based on three sub indices (iJ (i1) (h) The higher the value of the Index of Performance (i) the greater is the material s contribution to fire growth The higher the value of the sub-index 0) rhe greater the ease of ignition aod flame spread The highest product performance classification as defined in Approved Document B of the Building Regulations is Class O This is acLlieved if a material surface of a composite ploduct i~ either a) composed throughout of materials of
limited combustibility or b) a Class I material which has a tlre
propagation index (i) of not more than 12 and sub-index (i l ) of nor more than 6
01 J Class 0 is not a cla$sif1cation identified in any British Standard test
There are resin system reported to be classified to Class O when tested to BS476 Pcl1S 6 and 7 however designers need to ensure that such sysrems can be applied to their proposed design In propriety resinmat system available the fabrication techniques and COITect application are critical to the integrity of the reinforcing and clas ificatiol1 For example in some systems the u e of a non-fire retardant gelcont on a fire retardant substrate would reduce the classification For further information see HVCA publication DW144 Appendix D
55
DW154 SplCijiClIliol1 for Plastics Ductwork
x Guidance otes For nspectmiddoton Servicing a d
Clean-ng Access Openings
D1 GE ERAL This appendix highlight in ummary fOI111
the acce considerations that hould be made by the design r iD terms of inspection servicing and cleaning Having considered the seop and the design of the dUCI work system relative to the guidelines outlined below the designer should clearly indicate which levels of acces should be incorporated into the manufacture of a new duct work system (See Table 14 and Note I b low it
D2 DESIGN CONSIDERATIONS
D21 In ptction and servicing requireshyments are set out in Section 15 of Lhis specification
D22 Cleaning requirements are set out in the HVCA pubUcation TRl7 Guide to Good Practice Clean Lines of Ventilation Systems and the guide tates The precise location ize and
type of access would be dependent on the type of ductwork cleaning inspection and te ting metbods to b adopted Care protection and standards of cleanliness prior LO cOlllmisionin o
are set out in th AV A publication DWITM2 Guide to Good Practice Internal Cleanliness of New Ductwork Installations and th guide state Wh re specific limits of cleanliness are required ductwork sball be cleaned after installation by a spcialist cleaning contractor It will b in the interests of tht desioner botb financially and practically to cunsider employing a specialist c1eauing contractor at tbe
outset of a contract to internally clean newly installed ductwork prior to bandover This approach would reali e the following benefit shyi) Tb actual numb r of cleaning
access panels could be detennined to suit the method of cleaning to be adopted (This may be 1 s than the maximum requiremen listed under Lev 13 of Table 14)
ii) Clear directions could b given to the ductwork contractor as to tJle size and location of cleaning access panels that are required to be fitted during the mauushyfaclunng pro s
iii) The specialist cleaning operation prior to commi ioning vould enable the cleaning contractor to verify the practical acee requirement for the future cleaning operation associated -vitb a regular maintenance programme
iv) A specialist cleaning operation prior to commissioning would allow the designer to omit from the speeilicatiolJ the DWrrM2 requirem nt for factory sealing protection wipe downs and capping-off
v) Specialist Ieall ill 0 to the measurable standard defin d in TR17 will allow an objective definition of cleanline to be achieved
Car ful consideration must be gIven by the designer to the practl aJ problems associated witb the manufacture and fitting of suitably si Led access panel on small cross section duct and on the circular faces of rouod and flat oval ducts in particular
D23 Special con ideration must be given by the de igner to the practical problems associated with gaining personnel access to heavily congested ceiling areas and multi-la red du twork systems This approach would avoid
56
DW154 Spfciication for Plastics Ductwork
the possibility of access panels being D3 ACCESS 0 IN-LINE EQUIPMENT incorporated into a ductwork system at the This appendix unly covers acc il1spection manufacturing stage that were later found in through the ductwork body adjacent to an item practice to be inaccessible for either ervicing of in-line equipment and not openings in the or cleaning activities equipment itself
able 14 Acce requirements for inspection servicing and cleaning
HVCA PUBLICATIO REFE NeE (uidtgt 10 Gund Prartict
Adjace t OW144 Cleanliness orVcnlillltio S~lcr~ fRjJ7
in-line LeyeJ 1 Level 2 Level 3 ite sequipment pcdionSen lcin~ Section d C1eaniJl( SUn(O)lnspc lion Palle ltk~m_n
2011 (minimum OiL Jubje-ct to duct ~zel (ft~ -Panels
Control Da pcrs One (inspection) 203 One 300 mm x 200 mm Both sid Fire Dampers One (sCTjdJl~) 20211 One 300 0101 x 200 mm One side HeatingCooling Coils One (inspedion) 20213 One 300 mm x 200 mm (lIpstream) Both sides Attenuators (rectangular) None required One 300 mm x 200 mm (downstream) Both sides Attenuators (circular) one retluired One 300 mm x 200 mm (downstream) One side Filter Sections One (inspection) 20212 one required Uoth sides Air Turn Vanes None requjred None required Both sides Changes of Direction None required one required One side In-Duct FansDevices One (inspection) 20213 None required Both sides l
1 In the absence of any indication by the designer only Level ) access will be jncorporated into a new ductwork system
2 Tbe panel izes associated with Lev lis I and 3 acee s ar e middottablished by reference to Section 20 of DW144 and Section 2 ofTRll7 respectively
57
DW154 Speclfifatio for Plastics Ductwork
pA XE
B-bliography Included in this Bibliography are technical pUblications which may be of interest (0 ductwork designers fabricators and erectors and to tho e in the heating ventilatlng air conditioning industries generally nquiric should be made of the relevant organisation at the address quoted Since its publication other addresse contained within 0V154 mav have changed and some pubJicalions may have been superseded
HEATING AND VENTILATING CONTRACTORS ASSOCIATION
4 Palace Court London W2 4JG Telephone 020-7229 2488 Fax 020-7727 9268
Orders fo FlY A Publications Old Matlsion House Eamont Bridge Penrith Cumbria CA 10 2BX (Telephone 01768 864771 Fax 01768 86718) Email hvcapoblicationshvwelfarecouk DWn 44 pe ilicatiun for sheet mctal duclwork (Iow- mediulllshy
and high-pressure) 1998) DWIl4 A practical guide to dUGI ork I akage te ting
(revised 2000) DWII54 Specification for plastic~ duct rk DW171 Guide to good Practice for kitchen venlibtion system DW191 Guide to good pracuce glass fibre ductwoJk DwrrMI Acceptance cheme for new products - Redangolar cro
joint classification Guide to good pra tice - Internal cleanliness of new ductwork installations Guide to good practice for the design for the Installation of lire and smoke uampers
J 1Other puhlications
HampV safely guide 5th edition JS2 Tool box talks JS5 Weldlng Safety booklet JSI9 afety facts bo klet Fact sheets 1-24 2nd edition JS2J COSHH manual volume 1 Advice on compliance with the
regulations 1521A CO I-rH manual volume 2 Asses mcnt h ets JS23 Ri k management manual TR3 BrazinltT and bronze welding of copper pipework cUld sheet
(I 976) TR5 Welding of carbon steel pipework (1980)
TR6 Guide to Good Practice for Site Pre sure Testing of Pipework (19 0) Guide to good practice cleanliness of ventilation Ylem
CHARTERED IN TITUTlO OF BUILDING SERVICES E G EERS Delta House 222 Balham High Road London SW12 9BS rTelephone 020-8675 5211 Fax 020-8675 5449) CIBSE Guide Volume A Design Data Volume B In tallatiol1 and quipment Data Volume C Reference Data
CommlssioniJIg Codes These Codes eover the preliminary checkS eUing to work and regulation of vanous catcgories 0 plan The Codes give a guide to design implications Series A Air Distnbution Systems Series B Boiler Plant
ri s C Automatic Conlrol ystems Cr1es R Refrigerating Sy terns
Sene iN Water Distribution Systems
Technkal Memonllda TM 4 Design Notes for the Middle East TM bull Design otes for Ductwork TM 13 Minimi iog lhc Risk of egiounaires Disease
Research Reports RROI95 Ventilation system hygiene - A review of published
infomlatioo on lhe occurrence and ffects of Olltamination Rl~02J95 Air-to-air heal rec v ry RR0395 rnfluen e of HV C on smoke detectors
ATlONAL ENI [ERING SPECIFICATION LfMITED Southgatc hamber 3739 Southgate Street Winchester S023 9EH (Telephone 01962 842058 Fax 01962 R(8982) BUfLDING S RVICES RESEARCH AND [ ORMATION ASSOCIATIO Old Bracknell Lane West Bracknell Berkshire RG 12 4AH (Telephone Brackl1eU (01344) 426511 Fax 01344 487 -7 )
Application Guides AGln4 De tglJing Vana~le Volume middotylans for KOOnl
iir Movement AG1I91 Commissioning of V Sylcms in Buildings 11 6194 Fire Dampers
B) 94 cntiJalion or KitcneTls
AG389 The Commls ionin of Air Systems In Buildmgs AH2192 Commissioning of Bern - A ~ode of Practice TN2417 I Fire Dampec il) Ventilating Ducl
BEATING VENTILATING A AIR CONDITION G MA UFACTURERS ASSOCIATIO (HEVAC) HEVAC Henley Road Medmenham Marlow Buck SU 2ER (Telephone 01491 578674 ox 01491 575024 Emoimiddot infofetacouk)
Publicatjons Air Diffusion Guide Guide to Air Handling Unit Leakage Testing Guide to Good Practice Air Handling Unit Real Room Acoustic ~ st Procedure Specification for the ertiiicatioll ofAir Filters Method of Test for Water Rejection PerfOnTlatce of Louvrcs Subjected 1(1
Simulated Rainfall Test Procedure for Acoustic Loo cs Specification 10 Floor GrilJes - Types Performan e and Method ofTest Specification for the Determination of the Collection Efficiency of SilJ1d
Trap Louvre Domestic Mechwlical Vclltllalion Systems with Heal Recovery Fan Application Guid
~an and Ouctwork Installation Guide Guide to Fan Noise and Vibration
pecification of Requirements for JallJral Smoke and Heal Exhausl Ventilators
pecification for Powered Smoke and Heat Exhaust Ventilators
Specification of Requirements for Smoke Curtains Design Gujue of Smoke Ventilation for Single Storey Lodustrilll Building~
Including those with Mezzanine Floor and IIi Racked Storage Warehou es - Issue 3
Guidance for the Design of Smoke entilation YSlem for Covered and Undergrollnd Car Parks - lssue 1
Application of SOloke Control Equipment and Syst m Guid to Good Practice - Isue J
58
DW154 Sp(C~tiifitiol for Plastics Ductwork
BRITISH STANDARDS INSTIT TION Sales Department 101 P ntooviLle Road London NI 9ND (felephone 020-78 1 78801)
CP 413 1973 Ducts for building ervices
SS 476 Fire tes on building matenals and lruc(ure
Part 4 19 4 Non-combustibility lest or materials
Part 6 I Fire propagation lest for materials
Part 7 1993 Surface spread of tlarnJ tesls for materia
Part 20 1987 Fir resistance of elements of construction
Part 21 1987 Fire r sistlUlce of loadbeanng elements of construction
Part 22 1987 Fhe istallceofllon-loadbearing elemcllts ofconsttuclion Part 23 1987 Contribution of componcnts to the fire resistance 0 a
structure
Part 24t987 Fire resi lance of wl1lilation ductl
SS 5588 nan 919 0 Fire Precautions III thc desIgn and OOSlnJ lion of buildings
S 729 1971 Hot dip galvanized oatiugs (or irOIl aod stcel articles
BS 1449 Steel plate sheet and Irip
Pan 11991 Carbon steel plate heel and strip Part 2 1983 Stainless steel plate sheer and strip
and
B middotENJOI49-2 996 BSEN 10149- 1991)
BSEN 10131 1992
BSEN22063 Sprayed metal coarings 1994 Protection of iron and steel by aluminium and zinc against
atmospheric cOlosion Irotectiotl of iron and ste I against corro ion and oxishydation at elevared temperatures
BS 353 1981 Glossary of lerms relnting to thermal insulation
BS ISO 1479 Self-tapplngscrewsandmetallicdri c crew
B -lSO 7049
1994
B 4800 1989 Painl colour for building purposes B 4848 l0 rolled structural steel sections
Part4 1972 Equal and unequal angles BS 5422 1990 Specification for the use of therm illuating matcriulS
SS 5720 1979 ode of practice for mechanical veutilating and air C 11shy
dirionin bull in building
l3S PR 12814-1 Bend resting for plasric welds
SS PR 12814-2 Tensile testing for plastic welds
SS PR 13067 Appro altesting for plastic welds
BS PR EN I 100-] Vi ual in pection ofplaslic welds
SHEET METAL AND AIR CONDITIONING CONTR-CTORS NATIONAL ASSOCIATION INC (SMACNA) Headquarters 420 I Lafayeue Center Drive Chanlilly Virginia 2051-1209
Mailing Address pa Box 221230 Cbantilly Virginilt120 153-1230
Telephone (703) 803-2980 Fax (703) 803-3732
Accepted IJJdustry Pl3Gtice for Industrial Duct Constnlelion 197 ) i-rchitecmral Sheet kwl Manual ([993)
Comractors Guide lor Modification 10 ooslruerion Colllraets 1993 Ducted Eleclric Heat Guide for ir Handling Ssrerns (1994)
En~rgy ollservatioD Guidelines (1984) Energy Recovery Equipment yslClllS (199l
Fibrou GIns Duct onS1ntClion Standards (1992)
Fire Smoke amp Radiation Damper In tall Guide for HVA Syst ms (1992) Guide t leel Stack 1(95)
HVA Air Duct Leakage Test Manual (19 ) HVA COlllmissioning lvlanual (1994)
H A Duct Construction Standards-Metal amp Flexible (1995) Addendum 01 (Nov 1997)
HVA Duct Systems Inspection Guide (1989)
HVA ySlems-Application (1986) nVAC ByternS-DLlct D ign (1990)
HVi Systems-Testing Adjusting amp Balancing (1993)
indoor Air Quality Manual (1993) tcheu quipment Fabrication Guidelmes (1990)
Managers Guide for elding (1993)
Rectangular Industrial Duct Cons1TUction Standards (19 0) Round Industrial Duct oustmction Standards (1977)
Sei mic Restraint Manual (1991) (wl Appendix E 1993) SMACNA Ma le Index ()fTechnical Publications (1995) Tbennoplnstic Duct CPY ) Construction Manual 1994)
DEPARTME OF THE ENVIRO MENT (Publications Centre) H Stationery Oflice 5 Nine Elms Lane London SWS 5DR
MampEJ 011972 Electrical in tallat1011 in buildings ( ew Editiou)
IampE 0319 Healing hot and cold wat r steam and gas losla1lations for buildings
M amp - No4 1970 Central heating and hot and cold ~ ateT in tallations for
dwelling
M amp ENo100 1971 Mechanical ventilation for building~
ASSOCIATION FOR SPECIALIST FIRE PROTECTlO As ociation House 235 Ash Road AJdershot Hampshire GUl2 4DD
Telephone OJ25221322 Fax 0 J252 333901
lublicalioos Fire Ratcd and moke Outlet Ducrwork An Industry Guide t Design and InSlalla lioll
HEALTH AND SAFETY EXEC TIVE Rose Court 2 Southwark Bridge London SEl 9HS Telephone 020-7717 6000
TWJ THE WELD G TlTUTE Abington Hall Abington Cambridge CB16AL Telepbone 0 J223 89162
Publication DatJ Oil w~ldll1g of lhermopla lics
59
DW154 wciiwlioll for Plastics Ductwork
A -=--DIX
Factors
Specific gravity shy pp = 091 approx UPVC = 14 approx
Some miscellaneous conversion factors
To convert
Length Inches to millimetres Feet to metres
Multiply by
2540 03048
To convert
Millimetres to inches Metres to feet
vIultiply by
003937 3281
Area Square inches to square millimetres 6452 Square millimetres to square inches 000155 Square feet to square metres 00929 Square metres to square feet 10764
Volume Cubic feet to cubic metres Cubic feet to litres Gallons (UK) to litres
002832 2831 4546
Cubic metres to cubic feet Litres to cubic feet Litres to gallons (UK)
35315 00353
022
Mass Ounces to grams Pounds to kiJograms Tons to tonnes
2835 04536
1016
Grams to ounces Kilograms to pounds Tonnes to tons
003527 2205
09842
Volume flow Cubic feet per minute to cubic Cubic metres per second to cubic
metres per second 0000472 feet per minute 2119 Cubic feet per mIDute to litres Litres per second to cubic feet
per second 04719 per minute 2119
Motion Feet per minute to metres per second 000508 Metres per second to feet per minute 197
Pressure Inches water gauge to millibars 2491 Inches wateJ- gauge to pascals (Pa) 2491 I Pa = I ewton per square metre = 10-2 millibars
60
Heating and Ventilating Contractors Association Esca House 34 Palace Court London W2 4JG
Tel 020 7313 4900
e-mail contact Itvcaorguk web site wwwhvcaorguk
Fax 020 7727 9268
DW154 Sped(icalirm for Plastics Ductwork
PARTS
Hangers an Suppo ts
14 GENERA
141 Supports are an e sentiaJ part of me ductwork system and their supply and in tallation are normally the responsibility of the ductwork contractor The principl s are a I-rvCA publication DWIl44 Part 6 Section 19 and should be read in conjunction with this document
Design Note Designers may pecify specific requirements wbich will supersede guidance given in DW144
142 Rectangular ducts abl 8 give the- minimum requirements for
hanger and supports for un-reinforced ductwork
143 Circular ducts Table 9 gives the minimum requirements for hangers and upports for uD-reinforced ductwork
144 Vertical d cts The design of supports for vertical duct is dictated by site condition and where practical duc hould be upported at 4000 mm interval or where tbey pa s through a floor (but n ver exceeding 4500 mm) see Figs 17 amp J8
145 External ducts Where ducts are external to buildings and may be ubject to wind loading support should be plac d so as to restrain ide tl1ruSt and should allow axial movement as neces ary It is the respon ibility of me de igner to calculate the effect of the particular prevailing condition and to define any special upport requirement
146 Expansion joints Support shall be designed to permit axial movement only and shall e provided on eitl1er ide of expansion joint
I 1shy
I~
mm -Jp to 400
401 to 600 601 to 1000
Table B Hangers and Supports - rectangular horizontal ducts
Hanger Bearer Drop Roll Formed Rod
Long r Side
Cbannel ~-shy ~
---shy
Maximum ~pacing
4 52 3 _ -c Fig 15 - Figs 14 15 16 amp 2J
shy
mmm mmmm 240025 x 25 x 16 40 x 20 x 15 8 240040x20x15 40x 20 x 15 10 240040 x 20 x 1~510 40 x 20 x 15
shy
I
40 x 40 x 15 40 x 40 x 15 24001001 to 1500 I 10
Table 9 Hangers and Supports - circular horizontal ducts
Longer Side Hanoer Split Clips Maximum spacing Drop Roll f-ormed and Wrap-round Rod ~hannel Hang r
2 3 4I Fig 1920 amp 22Fig I
mm mmmm mm mm 25 x 25 x 15 IIp to 355 8 40 x 3- --1-_ 2400
2400
2400 2400
70x 6
40 x 5 SOx 5
40 x 20 x 15 40 x 20 x 15 40 x 40 15
10 10 10
356 to 600 601 to 1000 1001 to 1500
19
DW154 Spccijicutioll for Plastics Ductwork
147 Protection specification Any special coatingpaint Unless otherwise stated all support shall be finishes for protection against hostile manufactured in material as specified in this environments shall be advised by the designer
SUPPORT BEARERS
~ 14 Flg16 Inverted profile
angle I ~lIed steel
channel (alternatives) Fig 15 Profile channel (alternatives)
TYPICmiddotAL VERTICAL DUCT SUPPORTS Flat bar clipStiffening frame Outline ofinsulation stiffening frame or tlanged joint (if applicable) or flanged joint
Stiffening framc or flanged Joint
~~-I ( ee notes 10) I
r--~ -++- ~--4==J===4~---
Fig 17 Vertical rectangular ducts Fig18 Vertical circular ducts
The support bearer which depending on ducti tructural opening size could be either channel or angle section may be ll1ilised in any of the following arrangementsshy
a) To support the underside of a flat bar clip in halves (circular)
b) To support the underidc of either the stiffening frame oftbe flanged joint ofaoy duct section
c) To support either a stiffening frame Or a flanged joint below nsing drop rod srudding
20
DW154 Spediraiml for Plastics Ductwork
Arrangement of bearers and hangers (to be read in conjunction with Table 8 amp 9
wbich list material sizes relative 10 duel izes)
KEY Limits refer to actual duct size - insulation is additional - Typical
attachmentv -Atta hment t strucUlrcI to strucUlrc
I I
I - Flat Bar
I - Drop rod or - utlinc of lllddmg In ulillwn (if
applicable)
Alternative 7 drop rod or rt------------ 1 studdmg q I
I I Rectangular
ii i n 1
Fig 21 Rolled or profiled bearer Limit oncFig 19 Wrap-round hanger Limit 55 DIA
V v Drop rod orAllernaUC 1 1 tudding
drop rod or 1
-- -- 1studding and elded bas 1
I I0 -_
Limit 355 DIA Frg 22 Split clips Limit 1500 DIAFig 20 Flat strap hanger amp split clips
21
DW154 Specification for Plastics Ductwork
6PA deElned in J62 appropriate to the airflow pressure acoustic temperature and corrosion
General
15 ACCESSl SPECTION OPENINGS
151 General These are for inspectionservici ng on 1y
HVCA publication DWIl44 Part 7 - General Section 20 sets out the requirements for access applicable to this specification
152 Cleaningmaintenance Designers shall take specialist advice and then stipulate their requirements for the periodic internal cleaningmaintenance of ductwork and of the consequent need for adequate access for specialist cleaning equipment including the size type and locationfrequency of the actual access openings required
Appendix D sets out guidance notes for the consideration of cleaning access and also makes reference to the HVCA publication TR 17 Guide to Good Practice Cleanliness of Ventilation Systems which covers the su~ject
in greater detail
Note A majority of in tallations in which plastic ductwork is used are considered to have a nigb operational risk potential and provision of access should address this
16 REGULATI G DAMPERS
161 General Balancing dampers and control dampers are elements inserted into an air di tribution system or element of an air distribution sy middottem Balancng dampers permit modification of the air resistance of tbe system and consequently cbanging of the airflow rate Control dampers control tlle airflow rate and may in addition provide low leakage closure of the airflow
The deigner shall specify damper locations taking into consideration that good design practice requires a minimum of five times the diameter or width of the shortest side of uninterrupted flow between plant connections and the damper and select the damper type as
characteristics
1611 Balancing damper To achieve the required distribution of air in the ductwork system at inlets andor outlets for [hi purpose the damper blades are set and Jocked manually in position between fully open and fully closed
1612 Control damper To secure dynamic control of the air now in the ductwork system In thi function the damper will always be power actuated and may require to be modulated between fully open and fully closed and to be capable of taking up any position between these extremes In the fully open position the damper should have a minimum pressure drop In the fully closed position it will not necessarily achieve a complete shut off
162 Types of airflow control dampers Airflow dampers of various types are available for specific purposes as follows
1621 Single - blade dampers Single-blade dampers shall consist of a si ngle pi voted blade cOlllained withjn a casing or section of ductwork The blade shall be adjustable tbmugh a nominal 90 angle by means of a quadrant or similar operating mechanism Where automatic control of the damper is required the spindle shall be extended to enable a powered actllator to be mounted
Single-blade dampers shall have a maximum duct width of 400 nUll and a maximum duct height of 400 mm for rectangular ducts and for circular ducts a maximum diameter of 400 mm
1622 Multi-blade dampers Multi-blade dampers shall consist of a number of pivoted blades contained within a casing The blades shall be
22
DW154 Sedicalirm for Plastics Ductwork
adju table through a nominal 90deg angle simultaneously by intershyconnected linkage or gears connected to a quadrant or similar operating mecbanism Where automatic control of a damper is required a spindle shall be extended to enable a powered achlator to be mounted
There is no restriction on the size of duct in which multi-blade dampers or damper assemblie may be u ed Where dampers are required for blade lengths in excess of 750 mm the blades should be suitably reinforced or supponed 0
individual damper blade should exceed 200 mm in width
1623 Iris dampers Lris dampers shall consist of a nUlllber of radialty interconnected blades which open or close within a casing with duct COlll1cctions The blade shall be simultaneously adjusted by a quadrant or similar operating mechanism
Iris dampers shall be installed as specified by the manufacturers operating and installation instructions where the product is unidirectional with regard to airflow
lris dampers are available for circular ducts only in diameters up to 250 mm (it should be noted that the damper casin i appro)(imately twice the diameter of the duct)
1624 Backdraught dampers Air pressure operated uni-directional rectangular (single or multi-blade) with adapters if fitted to circular ducts
1625 Slide and blast gate dampers A damper [lsed as a shut off facility with an externaJ Lide bousing allowing the blade configuration to be fuJly inserted to fully extended for maxiDlUlll air flow
163 Construction
1631 Materials All products shall be protected against cOHosion as necessary and supplied in a fully finished condition as specified by the designer
1632 Dampers used in low and medium pressure systems The following recommendations apply to dampers forming an integral part of ducrwork with pressure classifications A and B air leakage limits
The dampers shaH be constructed to minimise distortion and prevent jammin in operation Th blade shall be sufficiently rigid to minimise movement when in the locked pOSitiOLl
The blades shall be securely fixed to the operating mechanism All balancing dampers shall have a locking device located on the outsid of the case and shall giv clear indication of the actlwl blad position All penetrations of the duct shall be fitted with suitable seals where necessary
1633 Dampers used in high pressure systems Regulatino- dampers used in duc[work sy tems to pressure cJassification C shall meet tbe construction requireshyments specified in 1631 and 1632 with operating mechanisms out of the air-stream
1634 Proprietary types of damper The use of any specific type of proprietary damper shall be confirmed by the designer In all cases proprietary dampers shall meet the relevant requirements of thi specification
1635 Damper casings Duct damper casings hall be constructed to meet th mllllmum
23
DW154 SpeciJimlioll for Plastics Ductwork
leakage Iim its sp cified for th c1uctwork ystem to which tbey are installed
In order to apply the square metre leakage calculatio as detailed in DW143 A Practical Guide to Ductwork Leakage Testing the reference casing area ball be taken as the perimeter ize of lh damper IDultipli d by the equi alent length of Imetr eg an 800 mm x 400 mm duct damper hall have a surface area for casillg leakag p donnan calculated as follow (2 x 08) + (2 x 04 x I
=24m2 casing area
Other pelforlllance ancl rating test methods for damp f and valves are specified in ISO 5129 and BSIE 1751 and are referenced belm a) Leakage past a closed damper
alve BSIE 1751 b) low ratepre sure requirement
characteri t cs BSIE 1751 c) Operational torque le ring
BSEN 1751 cl) Thermal transfer testing
BSIEN 17 I e) Reg nerated sound power levels
ISO 5129
164 Installation Dampers shall be imaalled in accordance will) any re Ievant ISO EN or British Standard 10 aJ bUT lcling regulation and national code of practice as well as the manufacturers recommendations
17 FIRE DAMPERS AND INT MESCENT SLEEVES
171 General Damper or sleeves arc requiTed on duct y~telll where the designer has -tjpulated the
duct wiU penetrate a fire compartment in the majority of application tbermopla ti ductwork is ugtecl where contamlDated corro ive or otherwise exceptional fumes are concerned it is preferable to use tire damp r which are externalJy mounted ie of the intmnescent operated crush typ
24
72 Fit-e rating The damper assembly should have a fUT
resi tance ratin o equal to that of the fir ban-jer it penetrate and ball be fire tested and rated to the timetemperature curv of B 476 Part 20 and 22
173 Intumescent sleeve At the time of writing this specification qualified test results were available for rectangular dampers and circular dampers up to 55 mm diamet r Manufacture have indicated that they are able t provide speci fications for other size and diameters This infonnation should be confirmed b th de igner Various type are available includino
tho e incorporating ruechanical closing plate and those operated anI by expanded iJllUme c nt media
In all ca es fire damp rs and intnmeBcen leeves shall be supplied and in taUed in
accordance with the manufacturer iJlStructioos and COSHH a essm nt
174 Other types Fire dampers of mious types are availabl for specific purpose~ ee HVCA publication DW144 The de igner should )lot (hat materials for con lt1Jction bould be uitablc for the par1icular application
ALL C SES FIRE DAMPERS AND fNT MESCENT SL _VES SHALL HE S PPLTED AND INSTALLED IN A ORDA CE WITH Tf--IE MANUshyPACTURERS STRUCTTONS AND COSHH ASSESSMENT
18 FLEXIBLEEXPANSION dOINT CONNECTIONS
181 General ploperties Tbe material u ed for flexibleexpan ion iojnt~
mu t meet the design r requirements for temperature air pressllrelfe resistance applicable to pl astic duct sy tem vibration and noi e br akout when incorporated into a jointconnection and shall comply ith lh standard of air-tigbtne specifi cl for the duct work sy tem of which it fOlms part (See Figs 23 24 5 26 27 amp 28 for typical con truclion clelai Is
DW154 SJecilimtol for Plastics Ductwork
Expansion joints
Fig23 Moulded bellows type (rectangular and circular)
Fig24
~F aiblc sleeve
__ liding sleeve
~~~~
Sleeve type (circufar)
Fig 25
AIRFLO
COnlinuou~
weld~
Flexible Iceve
PV A HOWN pp SE BACKING FLATS AS FIG 2
Sliding lee c Co1linuou
weld
Flanged sleeve (rectangular and circular)
25
DW154 Specificatiol for Plastics Ductwork
Flexible con ections
Fig 26 Flexible sleeve with clips (UPVC and PP)
--__ Flexible I eve
I
I
I CODn clioD to plant ~
Band clip
Fig27 Welded flexible sleeve (UPVC only)
Plastic)sed PVC slceve ~-- onll11uo1sly welded
onrreclion to planl ~
Fig28 Flanged flexible connection (UPVC and P )
t sp dally moulded flexible flanged connCClitlll
boil
C)nneclion to plant ~
26
DW154 Specificotiol for Plastics Ductwork
182 LOClt1tion Flexible joint are typicltllly lIsed at building expansion joint and fan inletsoutlets Any others required should be indicated on the de ign drawings Care should be taken to maintain alignment across jointsconnections
183 Length Flexible Jomts shall be kept as short as pra middottieable above a minimum eft ctive length of SO mm In no ca e shall a flexible joint exceed 250 mm in lengtb
184 Connections to rectang a ducts With flanged rectangular connections Ule tlexible material shall be held in pLace with flat pIa tic strip of not less U1an 6 mm thick ltlttached to the flanges using uitabJe fixings The more heavy weight type of fleAible mateLial may also be obtained formed into a channel ection with corners fitted to give a neat air tight j int For pigot connections the Be ible material shall b held in place with flat pIa tic trips n t less than 6 mm thick
t 85 Connections to circular ducts With tlanged circular connections the flexibl material shall be held in place with flat plastic backing strips or proprietary clip bands with screw or toggle fast ners
186 Welded flexible connections (Rectangular and Circular) Where the parent and llexibl material are from imilar ba ed products they can be joined to the duct u ing the welding method described in Section 823
19 PROTECT VE FINISHES
191 nles otherwise stated all ductwork shall be mallllfactured in mat fial as pecified in tbis specification Any special coatingpaint fmishes to be provid d by the duct work contractor sball be advisd by th de igner
20 CONNECTIONS TO BUILDING OPENINGS
201 Fanning and finishing building op nings are not the repoJlsibjlity of the duftw( rk contractor and the note that follow are for guidance purpo e only
2011 Openings in brick block or concrete walls shall have inset frames to provide a suitable means of fixing grille louver masking flanges or the tlanged ends of ductwork The illset frames shall be conslnlcted to maintain the structural int grity of the wlll and where applicable cavities shall be suitably lined
2012 Openin s in dry linino partItIons shall have inset frames a 2011
2013 Openjngs in cladding walls and roofs shall have flaoged leevesframes to provide a suitable means of fixing a 2011
2014 Horizontal and vertical opening xposed to oLltside atmo phere hall
be provided with a suitable weathering fini h at the external face especially where profiled cladding is used
2015 Timber framed op nings are not permitted In fj re compart ment barriers
202 Ductwork connections to building openings hall have a flange of suitable profile to permit practical fixing to the openillg frame In selecting the profile consideration shall be given to Tabl~s 2 and 10 in this specitication relating to duct ize and rating Gasket strip or sealant shall be ltlpplied between the tJaoge and building op ning frame
21 DISCHARGEEXHAUST TERMINAL
21 Tbese shall be vertical open ended and designed to meet and comply with current r gularions on contaminated flue The designer hall ensure that the de ign and perf rmance i suitable for its intended purpose Examples of some typical terminal designs are SbOiD in Figbull 102 10 bull 104 amp 105
27
DW154 SpedjimioTl for Plastics Ductwork
22 THERMAL INSULATION
221 The provision and application of thermal insulation to ductwork is not the responsibility of the ductwork contractor
222 Where ductwork is required to be preshyinsulated the specification should be agreed with tbe designer
223 Where the temperature of the air within the duct promotes condensation on the exterior surface of the duct and cause moisture penetration througb the thermal insulation vapour scaling may be required and in this case the most important requirement is to limit penetration of the seal
The extent of any vapour sealing of ductwork thermal insulation and the support method to be u ed must be clearly pecitled in advance by the designer
224 For detailed information on the thermal insulation of ductwork reference should be made to BS 5422 1990 which covers the specification for thermal insulation materials on pipes ductwork and equipment (in the temperature range -40degC to +700degC) and BS 5970 1992 which is a Code of Practic for Thermal Insulation of Pipework and Equipment (in the temperature range -lOOdegC to +870degC)
23 FIRE RETARDANT FINISHES ON PLAST C DUCTWORK
231 The designer should note tbat ductwork constructed to DW154 has no teted fire rating or information see Appendix C
24 REINFORCEMENT OF DUCTS WITH GRP LAMINATE
241 General Where ductwork is required in larg T izes than are covered by Tables 2 4 6 amp 7 or with the increased strength sometimes necessary for industrial use external reinforcement is normally pwvided by applicatioD of glass fibreresin laminate
GRP systems will bond satisfactorily with standard UPVC sheet but for pp it is
nece sary to use a specially prepared sheet with a glass fabric backing incorporated dOling manufactllfe
The detailed techniques of fabrication using GRP are outside the scope of this speci lcation but the following notes are offered for guidance of ductwork fabricators
242 Materials
2421 Quality The laminate is made up of polyester resin complying with BS 3532 and glass fibre complying with BS 3496 or BS 3749 The nominal ratio of resin to glass fibre should be 7030 by weight
2422 Minimum properties The laminate shall comply with the followiog mini mum pbysical properties
Tensile strength - 70 MNm Tensile modulus - 7 Gl m Flexural strength - 140 M Im Bond strength (hetween laminate and substrate Not less than 7MNm Bmcol hardnes Not le s than manufacturers specification
The GRP reinforcement educe the expansion of the parent material but the resultant stre ses arc well within rhe strength of the bond However the Iinear thermal expansion curve shown in Figs 34 amp 35 will serve as a guide
Surface resistivity electrkal propcltles and acoustical propertie are similar to the relevanl unreinforced materials The fire retarding properties of GRP may be improved by the use of specialisl laminating resin
2423 Forms available GRP Laminate should be built up from the separate materials ie resin aod glass fibre in the form of chopped
I strand mat or spray ravings
28
DW154 Spcification for Plastics Ductwork
2424 Workshop conditions Polyester resuls are sensItIve to lmperature and the workshop hould b maintained at a temperature of herween 20deg and 25degC HiOh relative humidities and damp onditions should be avoided A good rate of air change must be pro icled pJeferably by m chanical ventilation
2425 Storage of materials Resin and urin o agents shouJd be stored in dark cool condirions away from the working area and in confonnit with statutor requireshyments for tJle middottorage of flarmnable liquid Because of Ule Limited torage lif of the unmixed resin and curing a eot mal lials ~hould be ch eked before use to enLlfe that they are within the manufacturer pe ified sh If life (usually ix month from the dm of manufacrure)
Glass fi re should be stored separately und r clean dry conditions
243 Surface preparafon
2431 UPVC To achieve the specified bond strengtll the urface to which the GRP is applied mut first be thoroughly cleaned and then etched either by mechanical means or by the use of a suitable solvent
2432 pp with glass fabric backing To achieve the specified bond middottrength the fabric backing must be thoroughly impregnated Witll resin
244 Mixing the materials for use The re in 1 a three part mix compri lng base I sin hardener and accelerator The manufactur rs pecj[ied proportions are critical and th llUxmg sequenc pecified must be meticulously foUowed
The resin has a very limited life after mixing and before u e It is dependent on the characteri tics and bulk of th resin the alllount of hardener the degree and method of acceleration and the workshop onditions
245 Methods of application
2451 General The mixed resin may be applied by hand or b pray c1epoition The operation must b completed within the gel time of th y tern and tbe laminat fully cOI1olidated to achi v the phy ieal properties pecified
2452 Hand lay-up The duct surface i coated by hand with resin Llsing a brush and a mar of gla fibp orked in until full consolidation achieved Th proc is repeated untiJ th requird thicknes i obtained
2453 Spray depo Won The duct surface is coated WiUl re in by spray gun with the chopped glass roving added through a separate nozzle The full thickne i obtain d in layer with con olidation of each layer by hand roller
246 Construction
2461 General M ini mum COllst ructional requireshyments are pe itied ill Tabl 10 for rectangular and Table 1J for circular dUClS
2462 Joints and stiffeners Fig 29 30 31 32 amp 33 hoI TOSS
joint and tiffener for reinforced UPVC and PBPP duct
247 Worki g practices The fabrication of ductwork pecifiecl ill thi document i not affected by the addition of GRP
29
DW154 SfJcdJicatiOt for Plastics Ductwork
Table 10 Minimum constructional requirements shy
Longer Side Minimum Sheet Thicknes and
GRP Reinforcement
UPVC FBIPP 1 2 3
mm mm mm Up to 1000 3 plus 3 plus
06 kgm2 06 kgOIl GRP GRP
1001 to 2250 45 plus 3 plus 06 kgm 12 kgm
GRP GRP
2251 to 3000 45 plus 6 plus 12 kgm 12 kgm
GRP GRP
Cross Joints
UPVCFBPP 4
mm socket amp spigot
as Fig 30 or flanged as Fig 29
75 x 9 flange welded on both sides as Fig 29
75 x 9 tlange welded on both sides as Fig 29
rectangular GRP reinforced ducts
SlifTeners Maximum Spacing Between
JointsSljffeners UPVCIFBIPP UPVCFBPP
5 6 mm mm
75 x 9 flat 800 as Fig 31 or
50 x 50 x 5 plastic or MS inverted angle as Fig 32
or tormer as Fig 33
75 x 9 flat 600 as Fig 31 or
50 x 50 x 5 plastic or MS inverted angle as Fig 32
or former as Fig 33
75 x 9 flat 600+shyas Fig 31 or 50 x 50 x 5 plastic
or MS inverted angle as Fig 32
or former as Fig 33
Note 1 On rectangular duct up to 400 mm longer side no stiffeners are required 2 Applies to Tables 10 amp I I For COlJstructional operating temperature limits refer to Part 2 clause 5A 3 Tables 10 amp II apply to all pres ure classes up lo ]500 Pa
Table 11
Diameter
1 III
lJp to 1000
1001 to 1750
1751 to 2500
Minimum Sheet Thickness and
GRP Reinforcement
UPVC FBPP 2 3
mm mm 3 plus 3 plus
06 kgm 06 kgm GRP GRP
45 plus 3 plus 06 kgm2 18 kgm
GRP GRP
6 plus 6 plus 12 kglm2 18 kgm1
GRP GRP
Cross Joints
UPVCFBPP 4 III
socket amp spigot as Fig 30 or flaoged as Fig 29
75 x 9 flange welded on both sides as Fig 29
75 x 9 flange welded 00
both sides as Fi 29
inforced ducts
Maximum Spacing Between
JointsStiffeners UPVCIFBPP
6 mm 2400
800
600
Stiffencrs
UPVCFBPP 5
mm 50 x 9 flat as Fig 31
75 x 9 flat as Fig 31 or former as Fig 33 75 x 9 tlat as Fig 31 or t()rmer as Fi 33
ote On extruded tube tip to 600mm diameter no stiffenergt are required
30
DW154 Specificatioll for Plastics Ductwork
G - Cross joints and tiffeners
Fig 29 Flange Joint Fig32 Stiffener shy inverted angle
M artiPfCuQkbdd erttpObri) Wl111 RP tlddtlt
_- GRPloliu] lh~
Fig 30 Socket and spigot joint Fig33 Stiffener shy use of former
Fig 31 Stiffener Flat
I Pv FlPP ~ ~lmJaDUA1) d
OMrlQ rrnall 1( tQlS
25 STANDARD COMPONENT DRAWINGS AND ABBREVIATIONS
251 The illustrations in this section not only highlight where applicable geometric limjtations for the de ign and manufacture or ductwork components but also recommend
standard drawing representation terminology and abbreviations for both duetwork components and some of the more commonly used ancillaryplant items
252 Designers and surveyors should note that bills of quantities should provide a full description
3)
---
v
DW154 Spcc(fim(ml for Plastics Ductwork
Fig 34 Linear Thermal Expansion
u c 0 N ro 0)
b 0)
S
sect0
5 oS cl) 0)
~
on ~ ltl
c U
-30 -20 -10 0 10 20 30 40 50 60 70 80 90 TEMPRATURE C
~ V
-
~~c_ ~
~V
V ~
-7 ~
-- ~V ----
v
-6
+14
+12
+10
+8
+6
+4
+2
0
-2
--4
ig 35 Typical Design Stress tor UPVC and P
7
6
r shy 5E
-c E----0 4t) VJ 0)
ci5 0Jl 3
~
0)
Cl
2
1
o
UPVC
1
000
1
1
pp
- r-- shy r----- shy - t--shy I
__0
-30 -20 -10 0 10 20 30 40 50 60 70 80 90 TEMPERATURE C C
Note Figso 14 amp 35 shaded area refers to GRP reinforced duct
32
DW154 Speciicfltirm for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - REC ~NGULAR
Splilt~r Posilion W-mm pliucr
A B c 40]--QOO 1 W - -
601-1000 1 W4 Wf2 -
1001-1800 3 WI W3 W2
FIG DRAWING DETAfiS
tU]36 ATI Straight Duct with socket and spigol joint
rn [037 Straight Duct with flanged joints
[I []38 Straight Duct with flanged joints
rkJ Short Radius Bend
39 Applies to any augl and for duct up to 400 n11n wide
Minimum (I1m31 radills = 100 mm
Medium Radius Bend (a illustrated)
[kJ Applies to any angle
40 Long Radiu Bend Similar but radius = W
Throlll radius = W2 Applies to any angle
- Short Radius Bend with plitlers
I -shy -shy u co - t lt Li--_ 41 t 0 ~ I I I
~ I
L 1W
Minimum waal radius = 100 mm Splitters not required in bend angle less than 45deg
42 QJ1 Square Bend with turning vanes ij
3
DW154 SP(L~ficatioll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - RECTANGULAR
FIG DRAWl G DETADS
43
~
I v
L L Radius Tee with internal deflectors
44
~ Radiussed Twin Bend
45
Imiddot
er Swept Branch
46 U-
Sqoare Tee with Turning Vanes
47
~ f
Breeches Piece
48 0 y l Piece
34
DW154 Specificatioll for Plastics Ductwork
STANDARD COMPONENT RAWINGS - ECTANGULAR
55
54
51
50
53
52
49
FIG
~MX
RAWlNG
DmiddotMAX
EfjMAX
Minimum throat rndius = 100 mm
Rectangular shy Round Transformatioll
Eccentric Taper 225deg max in either plane Spliller are required for angles greater than 225deg and hould bi eet the angle between any side and duct centreline
DETATLS
Angled Offset
OUset Taper Splitters are required for angle greater than 22 0
and shoold bi eet the angl between any side and dUCI centrelinc
Mitred Offset
Concentrk Taper 2250 max in ither plane SpUtters are required for angle greater than 225deg and should bisect the angle between any side and duel c ntreline
Radiussed Offset
35
DW154 Splcilcuthm for Plastics Ductwork
STANDARD COMPONENT DRAWINGS ~ RECTANGU AR
Branch ducl DimCllsions widlh (W) (A)
urnl mm up lO 200 75
300 100 400 125 600 150
Ocr 600 200
FIG DRAWlNG DETAILS
56 poundplusmni~~ Rectan~lar - Flat Oval Transformation
57 [ Square Branch
58 er Angled Branch
Branch dUCI Dimensions wfdth (W) (A)
[- mm mm59 3shy Shoe Branch Up (0 200 75
--shy AIshy + 300 100
400 125
450 MAX 600 150
Over 600 200
Branch duct DimensIOn
rP X width (W) A)
60 - 1--shy _
~ mm mm
Bell Mouth Branch pto 200 75 300 100 t 400 125
600 150 Over 600 200
0=0 61 -
~ Bell Mouth
- shy T 4-5deg M x
--I 1-shy
TJ
62 X I ] I
Tele-scopic Joint I Illustrated with flangeL
X63
SBD Single Bladed Damper
36
---
DW154 Spedicatioll for Plastics Ductwork
STANDARD OMPONENT DRAWINGS - RECTANGULAR
DRAWING DETAILSFIG
64 on-Return DamperNRD shyshy
shyXbull
Multi-Leaf Damper Can be piggoted or flanged oppo cd or parallel blade
Alternative controls areshy
q p [gtshy
J HD65 Hand
~MD otori ed
PO Pneumalic
L-lt
l 13G 66 Blast Gate DamperX X
FireSmoke DampersSleeves
211r Ratinggtshy----
L_-
---
----
r----
Ir-- shy
IL- _-l
2hr
With i tallation frame
67 41 r Rating
4hr
Smoke damper SD
Intumc cent Sleeve L-d
37
DW154 Specijicutiolt for Plastics Ductwork
FIG
68
69
70
71
STANDARD COMPONET DRAWINGS shy REC ANGULAR
DRAVING DETAILS
gtshy Access Openings
AP 6 Access Panel - Rerno able
w [ ~ Access Door - Hinged
I ~le Inspection Cover
le -I reg -lt
~X X Flexible Connection
~ Drop Cheeked Radiussed Twin Bend
U Drop Cheek Bend
I
72 Air Flow SymbolX
38
DW154 Specifim[ioll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - ECTANGULAR
FIG DRAWING DETAILS
73
74
75
76
77
Q
Q
rp---t
~
V- I Ir---I
JL --11
THE ABOVE DETAILS TYPICAL PLENUM
Air Terminal Plenums
Plenum with side connection
Plenum with top connection
Cover plate with connection
Special plenum with connection
elescopic conn ction in direction of air flow
39
DW154 SpecijicotiOll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG
78
79
80
81
DRAWING
-23~---pound3-(MALE) (FEMAJE)
-t=j--_j(--d-shy
--L
~ THROAT RADI S= D AS T NDARD
e ~
THROAT Rjf)lU = D A MU)
DETAILS
Straight Duct With male and female connectors
Straight Duct With flange joint and slip joint
Bend MouldedIFormed Applies to any angle ego 30deg45deg60deg90deg Medium radius bend as illustrated Long radius similar but throat radius 0
Segmented Bend 90deg four section minjmum as illustrated
Other Angles 60deg = 3 sections 45deg = 3 sections 30deg = 2 sections
I
i
40 shy
DW154 Speciicafinll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG DRAWING DETAlLS
82 Segmented Twin Bend Radius = D2 max
May also be fabricated from tube
83 Equal Tee MouldedIFormed
84 -~ 1in Bend MouldedIFormed
85 Taper Concentric 1 0 as iUu trated Eccentric 30deg iJJcLuded angle
86 Short Taper
41
DW154 SpcUicatol1 for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG DRAWING DETAILS
87 30 max Offset
Angle Branch
Bran h dUCI Dimcnsions dia (D) lA)
Shoe Branch mm mm 88 Cl
Off rectanguJur Up 10 200 75 lOO 10 400 125
- 00 150 Over 600 200
Bl1IllCh duct DimenlOns din (D) (A
~-$a-Conical Branch mm mm
89 Also acceptable with Up 10 200 r
full conical surface 300 10
400 125
END VrE -shy 600 150 Over 600 200
90
m 75
100 12 150 200
mm Up to 200
_ 300 400
600 Over 600
iUtred Branch
Shoe Branch
J-L----U ~ Bell oulh Branch
ENDV1EW
93
92
91
42
DW154 Specificatiol for Plastics Ductwork
STANDARD OMPONENT DRAWINGS - CIRCULAR
FIG
94
DRAW G
I
~ 30deg 090deg
Breeches Piece
DETAILS
95 amp-----~ Blank End
~-----p Multi-Leaf Damper Can be piggolcd or fianged opposed or parallel blade
Alternative controls areshyri=-+- L-T~
I
---
LT~
I r- -
-+1
J HO Hand96
bMD Molori cd
PD Pneumatic
tl-shy bull
Single Bladed Damper 97 ~ saD
on-Return Damper Vertical application only 98 m~D
43
DW154 Sf1tcificatioll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG
99
100
101
102
DRAWING
$ I-
2hr
1 4hr
SD
~v I I
CO TINENTAL COWL
DETAILS
Iris Damper
Fi reS moke Dam persSleeves
2hr Ratillg
With installation frame
4br Rating
Smoke damper
Intumescent Sleeve
Access Openings
Access panel - removable
Access door shy hinged
fnspection cover
Discharge Continental Cowl
44
DW154 Sp(Cii(ltJll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
DRAWINGltIC DETAns
-
I
I
~
I I I High Velocity Discharge Terminal 103 I
I
I I
J I I 1 ~--
Offset Stack Discbarge Terminal 104 1
~ I e --(-
I
N
I
I
I~
I I Vertical Oischarge with Weather Cowl 105 I
--1--1 I
I
GAPI I
RTl AL DISC) lARGE WITH W ATIIER COWL
45
DW154 SpecUicatoll for Plastics Ductwork
STANDARD COMPONE T DRAWINGS - PLA TEQUIPMENTIMISCELLANEOU
FIG DRAWING DETAILS
106 ~~~ Rectangular Attenuator
107 ~- Circular Attenuator
108
~ Beod Attenuator
109 J ~(f) Heating Coil
110 J ftte Cooling Coil
III Jc[ Electric Heating Coil
112 X F
Humidifier
113 [H XX Axial Fan
114 ~fB1famp Noo-standard Ductwork Cross hntchillg (of any separate type) indicates by reference to a key any non DVil54 ductwork system
115 2llIIIIJIIIIIll Flexible Ductwork
46
DW154 SJeCUicll(iol1 for Plastics Ductwork
TABLE 12 - STANDARD ABBREVIAT ONS
ABBREVIATION FLL
AD Acces Door
AFF Axial Flow Fan
AHU Air Handling nit
All Aluminium
AP Acess Panel
AT Attenuator
AV Air enninal Unit
BE 81ank nd
BQ Blast ate Damper
CC Cooling Coil
CF Centrifugal Fan
CTA Cross alk Attenuator
CVU Constant Volume Unit
DP Drain Point
EEC Electric Heating Coil
El Expansion Joint
FAl Fresh Air Inlet
FA From Above
FB From Belo
fBPP Fabric Backed Polypropyl-ne Sheet
Flexle Flexible Connection
lexfD Flexible Du t
C False Ceiling CO an oil Unit
fD Fire Damper
FFL Finished Floor Level
FJ Flanged Joint
FOAM Rigid Polyurethane Self xtinguishing Foam
FOB Flat on Bottom
FOT Flat on Top
GAM Galvanised after ManufacttrJc
GRP Glass Reinforced Plastic
GSS Galvanised Sheet Steel
HC Heating oil
HD and controlled Damper
HH Hand Hole
HL High Level
HVD High Velocity Discharge
IC Inspection Cover
ID lri Damper
IFS Intumescent Fircleevc
47
DW154 Specification for Plastics Ductwork
TABLE 12 - STANDAR ABBREVIATION CONTINUED
ABBREVIATION
IU
L
tv1D
MS
NRD NTS
OBO
OE
PHD
PD
PP
PP
PRD
PVC
RFC
RSC
R
SBO
SO
S1 TST
SSL
TA
TB
TO TJ
TP
TV
TV
OS
UPVC
S
V
VAV
50 RSA
FULL
Induction Unit
Low Level
Motor controlled Damper
Mjld Steel
on Return Damper
at to cale
Opposed Blade Damper
Open End
Parallel Blade Damper
Pneumatic controlled Damper
Polypropylene
Self xtinguishing Polypropylene
Pressure Relief Damper
Polyvinyl Chloride
Rolled Form Chamlel
Rolled Steel Channel
R fUnit
Singl Blade Damper
Smoke Damper
Slip Joint
Stainl t el
tructural Slab Level
To Ab vc
To Blow
Top Down (In Direction of Flow)
Telescopic Joint
Test Point
TU111iog Vane
Top Up (In Direction of Flo )
Voles Otherwise Stated
Unpl3sticisecl Polyvinyl Chloride
Underside
Ultra Violet Light
Variable Air Volume
Rolled Steel Angle (Vith Size)
48
DW154 SJeriiflllioll for Plastics Ductwork
A2 DUCT PRESSUREAPPE DXA Ductwork con truct d to DWIl54 will bebullbullbullbullbullbullbullbullbullbullbullbullbullbull
Air Leakage From Ductwork To be read in conjunction with DW143 A practical guide to Ductwork Leakage Testing
CAUTION As highlighted ill both this docul1lenr and DW14 I lot ellough emphasis can be placed 01 the fact that except for high pressure class C the much more stringent ductwork constructional standard brolght about b the general acceptance of DW154 have irtlally negated the requirement for leakage-testing It is essential lO realise lhat except where it is mandatory this doclllllelll is nOl an endors ~lIlent of the rourine testing of ducts bllt purely a guide to outline the procedures for cononnity with the air leakage limits ill Table l Where the specified methods of assembly and
A3sealing of dlcls are u ed a vi ual inspection wil ordinarily sl~fll e for ver(iatioll of a well engineered and a ceptahfy airtight COl1strucrioll WHERE NOT MANDATORY DUCT LEAKAGE TESTING IS GENERALLY AN UNJUSTIFIED AND SUBSTANTIAL EXPENSE
A1 INTRODUCTION L akage from ducted air distribution systems is an Lmportant consideration in the design and operation of ventilatjon and air conditioning middotystems A ductviork t)ystem tbat ba limited air leakag within defiucd limits wiH cnsUft
that tile design characteristics of the sytem can be maintained It wilJ also ensure that energy and operatLonal cosb are maintained at optimum levels DucLwork constlucted and Ulstalled in accordance with DW154 should minimise a level of air leakage that it) appropriate to tll operating static air pre sur in tile system
A4However it is recouuised that tbe environment in wtJich middotystems are installed is not always conducive to achieving a predictable level of quality in term of system ajr leakage and it is therefore accepted that designer may sometimes require tlle ystem to be tested in part or in total It should be ecogni ed that the testing of duct systems add a ignificant cost to the installation and incur some extra tjm within the programme (Se 47 and 64 re mandatory te-sting)
manufactured to a structural standard that is compatible with the system operating pressure There are three classes of duct con truction to eorre pond with the three pre ure clas meations Class A Lo pressure ducts suita le for a maximum positive operating pressure of 500 Pascal and a maximum negative pressure of -500 Pascals Class B IVledium pressure ductmiddot suitable for a rnaxilnuJJl positive operafjn o pressure of 1000 Pascals and a maxllnum negative pre sure of -750 Pa cal Class C High pre sure ducts suitable for a maximum po ilive operating pressur of 2000 Pa cals and a maximum negativ pres ur of -750 Paltcals
LEAKAGE FROM DUCTWORK Leakao-e front pia tic air ducts occur at the joint~ and is therefore proportional to the total surface area orthe du twork in th system Tb level of leakage i imilarly related to tIle air pres ure in th du t system and whilst there LS n precis formula for calculating the level of air los it i generally accepted that leakage will increase in proportjon to pressure to rbe pOvver of 065 The effect of air leakage from high pressure velocit ductwork is critical tn terms of system perfomlan dege energy consumption and the risk of high frequency noise as ociated with leakage These problems are le critical with medium pressure 10 ity systems but should be con idered Low pres mevelocity ducts present the lowe~t
ri k in tenn of tbe effect of leakage on the operation of the s stern
SYSTEM LEAKAGE LOSS As there i no di ct relatLonship between th volume of air conv yed and the surface area f the ductwork sy tern required to match the building configuratmn it is difficult to express air leakage a a percentage of total air volume Similarly the operating pressure will vary throughollt lh 3 system and a leakage is related to pre me the calculations ar comple However it is generally ac epted tbat in typical good quaJjty systems the leakage from
49
DW154 Specificatioll for Plastics Ductwork
each class of duct llnd r operating condition will be io the region of CIa S A low pressure 6 Clas B medium pres un 3 Clas C high pressure 2
A5 SPECIFYING AIR LEAKAGE TESTING Re peeting both the co -t and programme implications a sociated with te ling du 1 for leakage the designer may for example indicate that a particular system is te ted as follow
a) High pressure ducts - all tested b) Medium pr ssure duets - 10 of the
ductwork shall be s eet d at random and tested
c) Low pre sure - unte ed In any case where a random te t i elected for medium pre sure ductmiddot the followin c1au~e is suggested for inclusion by the de ign r
The designer hall elect at random a maxirnwlI of 10 of the dUCl system to bt tested for air leakage The duct hall be tested af the pressure recommended in Table J3 for the assifi atiol for the ectiol1 of the ductwork that is to be tested The tests shall be carried Ollt as the work proceeds and prior to the application of thermal insulation In the event of test failure of the randomlY selected section the designer shall have The right to select two La1her e tiolls at random for resting Where succes ive failures are identified there shall be a Tight to require rhl COl11raCWr 10 apply remedial attention to the complete ductwork system Th contractor shall provide documented eviden e of the calculalions used to arrive (1
the allowable 10 I for the section to be tested and the client or his agent shall willess and sign the results of the test
able 13 Air leakage rates
Maximum leakage of duct work Static
prcssUft Low-pressure edium-prc-sure I Iigh-prebull me diJfercntial Class A Class B Class C
1 2 J 4 Pa Litres per second per quare metre of surface area 100 054 018 ZOO 084 028 300 110 037 400 132 044 500 153 051 600 058 019 700 064 021 800 069 023 900 075 025
1000 080 027 1100 1200 1300 1400 1500
029 030 032 033 035
1600 1700 1800 1900 2000
036 038 039 040 042
Note Recommend d mean test presures are highlighted iD bold type with the actual selection being left to tll test operator
50
DW154 Sfeeiieaioll for Plastics Ductwork
A9
A10
and air leakage classification for the y em under test
DESIGNERS CALCULATIONS The designer can middotaJculate with reasonable accuracy the predicted total loss from a ystem by
a) Calculating the operatin presure in each ection of the sy tern
b) Calculating the surface area of the ductwork in each correspondin pre lire s ction
c) Calulating the allowabl~ los at the operating pressure for each ection of the system (see table 13 for allowable leakage figures)
VARIABLE PRESSUR S IN SYSTEMS De igner can achieve significant co t saving by matchina operating pressures throughout the system to constmctional standard and appropriate air leakage testing eO the practice of specifying construction tandards for whole duct sy tems based on fan discharge pre sure may incur unnece sary costs on a project For example ome large sy terns ould well be classiC ed for I akage limits as follows
Plant room risers CJas C Main floor distriblltJou CIa B Low pre sure outlets Cla A
A6 SPECIAL CASES There may be ~itLlations on a project where circumstance dictate thal pecial consideration be given to containing air loss s eg a long mn of duclwork may incur a di -proportjonate level of air 10 s In ca es such as thi example the designer can specify an improved tandard of airtighmess ie 80 of alJo~able 10 s for la B Ju ts The designer sbould not specif a CIa C t sI at CIa s C pressure for a CIa s B ducl
A7 SUGG S ED RANGE OF TES ING
A8 TESTING OF PLANT ITEMS Items of inline pJant (eg Fig 106 to 115) will not normaUy be included in an air I akage test The dllctwork contractor may indud such itelllS in tbe te t jf rh quipm ot has a certificate of COnfOlnlity for Ihe pres ure clas
bull High pressure duct bull Medium pre sure ducts bull Low pre sur ducts bull Exposed extract syst ID bull Ceiling void extract
systems bull Secondary ducts from
VAV or fan coil units bull Flexjble duct bull Final connections and
branches to grille and diffusers
100 test See A5 Untested UDt sted
Untested
Untested Untested
Untested
SI
i
DW154 SJecijicafion for Plastics Ductwork
ig 116 Permitted leakage at various pressures
Leakage in litres per second per square metre duct surface area
Vgt
o ltgt 0 ltgt N
ltgt Cgt
0 0 cc
0 0
~
g =
g ~
c 0
J
ltgt 0 I
~ ] tn
ltgt ltgt
In ol
~ 0 ~ 8 ~
~
c ltgt ltgt
~ CJ
~ ~ ~ ~ 8
0shyij
~ ~ ~ t
ltgt ltgt 00
l
~
~ Q
c C
~ rshy
e ltgt
I 1
I Cgt ltgtv
c Co ~
~~ ~ 10
I
0 Cgt
fJshyq 410 ) 1 ltgt
ltgt N
~ shy ltgt ltgt
~ I 1
c
52
DW154 Specificatio for Plastics Ductwork
Example of a completed test sheet Test No
General
Name of job N~ jC43Pt(r2lef Building Repound ~(~~0
Part 1 - Physical details
a Section of duct work to be tested ~(diffPIfff~el1f3rd Floor
b Drawing Number g91~~ c ssure aSSJ L atlOn V~Jl~IRfYgtg~~lPre Cl T Class C
d Test static pressure -(9 raErq~ ~~~~-~~J~~~ ~~ ~~~~ll
Leakaoe factor 9~-tre3$ecMz I OM REFTOTABLE 13)e b bullbullbullbullbullbullbull
f Surface area of duct under test Q~tJJItetre$ CPROMCALCU TIO BELOW)bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull ampampamp bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull
g ]Vlaxi mum permitted leakage -~ (~i~~0 ~~r~~ ~~~l-~-11~ ~~~Q
Part 2 - Test particulars
a Duct static pressure reading 9QFt~q~ ~ middot~~~1 ~~
b Manufacturer and type of liow measuring d vice (-~~~cJ~Y-9Q7EYg c Range of measurement of now measuring device QtP)OQ~(e~~~0I~~~~1~I~ ~~~~~~W~
d Reading of flm measurin o device pmiddot IFROM RIO)ftscag ~
I (DERlVED [ROM CHART SUPPUED WITH RIG US 0 ud)1e Interpreted air flow leakage rate ~(~~~f~~~ (~l~~~~~~~~~~~~~~~~~I
f Duration ~~~~~norn~allY l~ lnil1Ut~~d~~~ it1~ W~ Date of test ~(lITled ut by Wltll s ed by ~ ~
(~lJ MIJLrr) (Si~rrfltJUYJ
Printed Name 1~g0f~ Printed Name ~~Y~9~ and Company 7jl~~~~~( UJd CompanY AB COII$Itallt8
Width and depth or diameter
Periphery ength Area
millimetreS millimetres metre qL1are metre
800 x 750 3100 1755 5440
600 x 650 2500 557 1193
300 x 300 1200 120 144
305 din 958 700 670
250 dia 785 450 353
TOTAL 8000
53
DW154 Specijilarion for Plastics Ductwork
pA XB
Guida ce No es For he ransport Handling and
Storage of uctwork
avoid damage to adjacent duct panels In somc ca es particularly on con acts calling f r repetitive sizes the use of timber jigs and spacers may be justified Where reduced bulk and greater protection are major factor such as consignments for export transporting ductwork in L shape sections may justify the increa ed ite as embly co ts
It is recommended that before a contract is finalised that consideration is given to the subject of site acces material handling and storage as tbcy havgt a strong influence on the cost efficiency of the overall activity of ductwOlk installation
B3 Handling To minilnise th risk of damage duct sections should be clearly identified and deliveries to site should be closely linked to the installation programme so as to avoid accumulation of
B1 Storage and Handling of Ra Material Material should be stored in suitably designed racking out of direct unJight Where possible the e racks should be metal to earth Edges of cut she t may be harp and protective gloves are advised Wearing teel toe-capped boots is recommended Most pIa tic sheet is manufactured with smootb mfaces andor is suppLied with protective coating Care must be taken to prevent accidental lippag of stacked materials Beiuoshy good electrical insulators the movement of stock unless earthed will allow the build up of stati All stock shapes are chemically stable at normal temperature Whil t some raw materials used in their manufacture may themselves pre ent a toxic hazard once incorporated into the lOck bape they no long r constitute such a hazard and no dermatitic bazard are known nor are any
unfiJied ductwork and minimise double handling It is important to recognise that ductwork panels joint and corners arc susceptible to damage and care must be taken wheu band ling such material through a site During handling individual item of duct work may be liable to light cross sectional deformation until thev become an integral pan of a completed ductwork system Whilst this may temporarily detract from its intended appearance thi deformation will not have any detrimental effect on the functionality of the finally a semblecl system Installation of duct work and asociated plant items ill illevitably involve manual handUng The responsibi Iiry of employers and employees to a ses the risk of personal injury during mallual handling operations is et out in the HS E publication L23 Guidance on Manual Handling Regulations 1992
environmental problems expected 84 Site storage
B2 fransport Large capacity vehicles with high-sided open or closed-top bodies are tlle mo t suitable for the transport of dllctwork Careful consideration should be given to the
Adequate floor space IDust be provided within tbe building for the site storage of ductvork Such storage shalt make due allowance for thc stOf(ne of ductwork in stacks such that access ~ egt
between them is of sufficient width to pennil the removal of item without interference to
unloading of transport on sit a not all siJes b n fit from the material handlino- and access facilities that exi [ in a manufacturing workshop such as crane- fork-lifts or loading bay Site handJiog facilities along with
adjoining sta ks Ductvork components should be positioned so a to avoid crushing Ductwork of small panel size may be stored horizontally however care should be exercised to ensure that tack sizes are limited 10 within
ehicular acce s restrictions may itilluence the type and ize of transport to be uWised
engtlls of ductwork should be positioned 0
the tmctural strength of the duct sections to prevent distortion of the lower sections within the stack
as to avoid crushing Lengths Witll projections such as branches and bends i1anges girths damper quadrauL should be loaded so as to
54
DW154 S1tciic(ltioll for Plastics Ductwork
85 Internal cleanliness of new ductwork The site storage of ductwork introduces the important cODsideration of maintaining the internal cleanliness of the ductwork R feren e should be made to HVCA documentshybull DWffM2 Guide to Good Practice - internal
Cleanliness of New Ductwork Installations If the above conditioDs can not be satisfied consideration should be given by tJle designer to amending the specification to include for Po t Installation Cleaning as covered by tJ1C HVCA documentshybull TRJ17 Guide to Good Practic - Cleanliness
of Ventilation Systems
APPE DIXC
Fi e Retardant inishes C1 Improvement in the fire retardancy of plastic
ducts can be achieved to varying degrees and is wholly dependent llPOll the surface coating laminating resin selected and construction specification adopted In some instances smoke emission is coILSidered equaUy with other speci fication requirernen ts of the materials resistance to ignition and bumjng It is therefore important for design rs to establ ish the clients and officers detailed requirements and not rely on a tbird party interpretation of fire resisting or fire retardant Where possible the specification should refer dir etly to compliance with a British or European Standard identifying the specific sections applicable There are various types of resin and mat rcLnforcements that can achieve a Class 1 surface spread of flame ratin o when tested according to BS476 Part 7 (1987) This test puts materials illto Class I - 4 in descending order of perfoDllance according to the rat and extent of flame spread over their surfac under standard beating conditions Materials should also be tested for flre propagarion to BS476 Part 6 (1989) Tbi tesr measures the amount and rate of heat evolved by the material when subjected to standard heating
conditions Test results are given as an index of Perfonnance (i) whicb is based on three sub indices (iJ (i1) (h) The higher the value of the Index of Performance (i) the greater is the material s contribution to fire growth The higher the value of the sub-index 0) rhe greater the ease of ignition aod flame spread The highest product performance classification as defined in Approved Document B of the Building Regulations is Class O This is acLlieved if a material surface of a composite ploduct i~ either a) composed throughout of materials of
limited combustibility or b) a Class I material which has a tlre
propagation index (i) of not more than 12 and sub-index (i l ) of nor more than 6
01 J Class 0 is not a cla$sif1cation identified in any British Standard test
There are resin system reported to be classified to Class O when tested to BS476 Pcl1S 6 and 7 however designers need to ensure that such sysrems can be applied to their proposed design In propriety resinmat system available the fabrication techniques and COITect application are critical to the integrity of the reinforcing and clas ificatiol1 For example in some systems the u e of a non-fire retardant gelcont on a fire retardant substrate would reduce the classification For further information see HVCA publication DW144 Appendix D
55
DW154 SplCijiClIliol1 for Plastics Ductwork
x Guidance otes For nspectmiddoton Servicing a d
Clean-ng Access Openings
D1 GE ERAL This appendix highlight in ummary fOI111
the acce considerations that hould be made by the design r iD terms of inspection servicing and cleaning Having considered the seop and the design of the dUCI work system relative to the guidelines outlined below the designer should clearly indicate which levels of acces should be incorporated into the manufacture of a new duct work system (See Table 14 and Note I b low it
D2 DESIGN CONSIDERATIONS
D21 In ptction and servicing requireshyments are set out in Section 15 of Lhis specification
D22 Cleaning requirements are set out in the HVCA pubUcation TRl7 Guide to Good Practice Clean Lines of Ventilation Systems and the guide tates The precise location ize and
type of access would be dependent on the type of ductwork cleaning inspection and te ting metbods to b adopted Care protection and standards of cleanliness prior LO cOlllmisionin o
are set out in th AV A publication DWITM2 Guide to Good Practice Internal Cleanliness of New Ductwork Installations and th guide state Wh re specific limits of cleanliness are required ductwork sball be cleaned after installation by a spcialist cleaning contractor It will b in the interests of tht desioner botb financially and practically to cunsider employing a specialist c1eauing contractor at tbe
outset of a contract to internally clean newly installed ductwork prior to bandover This approach would reali e the following benefit shyi) Tb actual numb r of cleaning
access panels could be detennined to suit the method of cleaning to be adopted (This may be 1 s than the maximum requiremen listed under Lev 13 of Table 14)
ii) Clear directions could b given to the ductwork contractor as to tJle size and location of cleaning access panels that are required to be fitted during the mauushyfaclunng pro s
iii) The specialist cleaning operation prior to commi ioning vould enable the cleaning contractor to verify the practical acee requirement for the future cleaning operation associated -vitb a regular maintenance programme
iv) A specialist cleaning operation prior to commissioning would allow the designer to omit from the speeilicatiolJ the DWrrM2 requirem nt for factory sealing protection wipe downs and capping-off
v) Specialist Ieall ill 0 to the measurable standard defin d in TR17 will allow an objective definition of cleanline to be achieved
Car ful consideration must be gIven by the designer to the practl aJ problems associated witb the manufacture and fitting of suitably si Led access panel on small cross section duct and on the circular faces of rouod and flat oval ducts in particular
D23 Special con ideration must be given by the de igner to the practical problems associated with gaining personnel access to heavily congested ceiling areas and multi-la red du twork systems This approach would avoid
56
DW154 Spfciication for Plastics Ductwork
the possibility of access panels being D3 ACCESS 0 IN-LINE EQUIPMENT incorporated into a ductwork system at the This appendix unly covers acc il1spection manufacturing stage that were later found in through the ductwork body adjacent to an item practice to be inaccessible for either ervicing of in-line equipment and not openings in the or cleaning activities equipment itself
able 14 Acce requirements for inspection servicing and cleaning
HVCA PUBLICATIO REFE NeE (uidtgt 10 Gund Prartict
Adjace t OW144 Cleanliness orVcnlillltio S~lcr~ fRjJ7
in-line LeyeJ 1 Level 2 Level 3 ite sequipment pcdionSen lcin~ Section d C1eaniJl( SUn(O)lnspc lion Palle ltk~m_n
2011 (minimum OiL Jubje-ct to duct ~zel (ft~ -Panels
Control Da pcrs One (inspection) 203 One 300 mm x 200 mm Both sid Fire Dampers One (sCTjdJl~) 20211 One 300 0101 x 200 mm One side HeatingCooling Coils One (inspedion) 20213 One 300 mm x 200 mm (lIpstream) Both sides Attenuators (rectangular) None required One 300 mm x 200 mm (downstream) Both sides Attenuators (circular) one retluired One 300 mm x 200 mm (downstream) One side Filter Sections One (inspection) 20212 one required Uoth sides Air Turn Vanes None requjred None required Both sides Changes of Direction None required one required One side In-Duct FansDevices One (inspection) 20213 None required Both sides l
1 In the absence of any indication by the designer only Level ) access will be jncorporated into a new ductwork system
2 Tbe panel izes associated with Lev lis I and 3 acee s ar e middottablished by reference to Section 20 of DW144 and Section 2 ofTRll7 respectively
57
DW154 Speclfifatio for Plastics Ductwork
pA XE
B-bliography Included in this Bibliography are technical pUblications which may be of interest (0 ductwork designers fabricators and erectors and to tho e in the heating ventilatlng air conditioning industries generally nquiric should be made of the relevant organisation at the address quoted Since its publication other addresse contained within 0V154 mav have changed and some pubJicalions may have been superseded
HEATING AND VENTILATING CONTRACTORS ASSOCIATION
4 Palace Court London W2 4JG Telephone 020-7229 2488 Fax 020-7727 9268
Orders fo FlY A Publications Old Matlsion House Eamont Bridge Penrith Cumbria CA 10 2BX (Telephone 01768 864771 Fax 01768 86718) Email hvcapoblicationshvwelfarecouk DWn 44 pe ilicatiun for sheet mctal duclwork (Iow- mediulllshy
and high-pressure) 1998) DWIl4 A practical guide to dUGI ork I akage te ting
(revised 2000) DWII54 Specification for plastic~ duct rk DW171 Guide to good Practice for kitchen venlibtion system DW191 Guide to good pracuce glass fibre ductwoJk DwrrMI Acceptance cheme for new products - Redangolar cro
joint classification Guide to good pra tice - Internal cleanliness of new ductwork installations Guide to good practice for the design for the Installation of lire and smoke uampers
J 1Other puhlications
HampV safely guide 5th edition JS2 Tool box talks JS5 Weldlng Safety booklet JSI9 afety facts bo klet Fact sheets 1-24 2nd edition JS2J COSHH manual volume 1 Advice on compliance with the
regulations 1521A CO I-rH manual volume 2 Asses mcnt h ets JS23 Ri k management manual TR3 BrazinltT and bronze welding of copper pipework cUld sheet
(I 976) TR5 Welding of carbon steel pipework (1980)
TR6 Guide to Good Practice for Site Pre sure Testing of Pipework (19 0) Guide to good practice cleanliness of ventilation Ylem
CHARTERED IN TITUTlO OF BUILDING SERVICES E G EERS Delta House 222 Balham High Road London SW12 9BS rTelephone 020-8675 5211 Fax 020-8675 5449) CIBSE Guide Volume A Design Data Volume B In tallatiol1 and quipment Data Volume C Reference Data
CommlssioniJIg Codes These Codes eover the preliminary checkS eUing to work and regulation of vanous catcgories 0 plan The Codes give a guide to design implications Series A Air Distnbution Systems Series B Boiler Plant
ri s C Automatic Conlrol ystems Cr1es R Refrigerating Sy terns
Sene iN Water Distribution Systems
Technkal Memonllda TM 4 Design Notes for the Middle East TM bull Design otes for Ductwork TM 13 Minimi iog lhc Risk of egiounaires Disease
Research Reports RROI95 Ventilation system hygiene - A review of published
infomlatioo on lhe occurrence and ffects of Olltamination Rl~02J95 Air-to-air heal rec v ry RR0395 rnfluen e of HV C on smoke detectors
ATlONAL ENI [ERING SPECIFICATION LfMITED Southgatc hamber 3739 Southgate Street Winchester S023 9EH (Telephone 01962 842058 Fax 01962 R(8982) BUfLDING S RVICES RESEARCH AND [ ORMATION ASSOCIATIO Old Bracknell Lane West Bracknell Berkshire RG 12 4AH (Telephone Brackl1eU (01344) 426511 Fax 01344 487 -7 )
Application Guides AGln4 De tglJing Vana~le Volume middotylans for KOOnl
iir Movement AG1I91 Commissioning of V Sylcms in Buildings 11 6194 Fire Dampers
B) 94 cntiJalion or KitcneTls
AG389 The Commls ionin of Air Systems In Buildmgs AH2192 Commissioning of Bern - A ~ode of Practice TN2417 I Fire Dampec il) Ventilating Ducl
BEATING VENTILATING A AIR CONDITION G MA UFACTURERS ASSOCIATIO (HEVAC) HEVAC Henley Road Medmenham Marlow Buck SU 2ER (Telephone 01491 578674 ox 01491 575024 Emoimiddot infofetacouk)
Publicatjons Air Diffusion Guide Guide to Air Handling Unit Leakage Testing Guide to Good Practice Air Handling Unit Real Room Acoustic ~ st Procedure Specification for the ertiiicatioll ofAir Filters Method of Test for Water Rejection PerfOnTlatce of Louvrcs Subjected 1(1
Simulated Rainfall Test Procedure for Acoustic Loo cs Specification 10 Floor GrilJes - Types Performan e and Method ofTest Specification for the Determination of the Collection Efficiency of SilJ1d
Trap Louvre Domestic Mechwlical Vclltllalion Systems with Heal Recovery Fan Application Guid
~an and Ouctwork Installation Guide Guide to Fan Noise and Vibration
pecification of Requirements for JallJral Smoke and Heal Exhausl Ventilators
pecification for Powered Smoke and Heat Exhaust Ventilators
Specification of Requirements for Smoke Curtains Design Gujue of Smoke Ventilation for Single Storey Lodustrilll Building~
Including those with Mezzanine Floor and IIi Racked Storage Warehou es - Issue 3
Guidance for the Design of Smoke entilation YSlem for Covered and Undergrollnd Car Parks - lssue 1
Application of SOloke Control Equipment and Syst m Guid to Good Practice - Isue J
58
DW154 Sp(C~tiifitiol for Plastics Ductwork
BRITISH STANDARDS INSTIT TION Sales Department 101 P ntooviLle Road London NI 9ND (felephone 020-78 1 78801)
CP 413 1973 Ducts for building ervices
SS 476 Fire tes on building matenals and lruc(ure
Part 4 19 4 Non-combustibility lest or materials
Part 6 I Fire propagation lest for materials
Part 7 1993 Surface spread of tlarnJ tesls for materia
Part 20 1987 Fir resistance of elements of construction
Part 21 1987 Fire r sistlUlce of loadbeanng elements of construction
Part 22 1987 Fhe istallceofllon-loadbearing elemcllts ofconsttuclion Part 23 1987 Contribution of componcnts to the fire resistance 0 a
structure
Part 24t987 Fire resi lance of wl1lilation ductl
SS 5588 nan 919 0 Fire Precautions III thc desIgn and OOSlnJ lion of buildings
S 729 1971 Hot dip galvanized oatiugs (or irOIl aod stcel articles
BS 1449 Steel plate sheet and Irip
Pan 11991 Carbon steel plate heel and strip Part 2 1983 Stainless steel plate sheer and strip
and
B middotENJOI49-2 996 BSEN 10149- 1991)
BSEN 10131 1992
BSEN22063 Sprayed metal coarings 1994 Protection of iron and steel by aluminium and zinc against
atmospheric cOlosion Irotectiotl of iron and ste I against corro ion and oxishydation at elevared temperatures
BS 353 1981 Glossary of lerms relnting to thermal insulation
BS ISO 1479 Self-tapplngscrewsandmetallicdri c crew
B -lSO 7049
1994
B 4800 1989 Painl colour for building purposes B 4848 l0 rolled structural steel sections
Part4 1972 Equal and unequal angles BS 5422 1990 Specification for the use of therm illuating matcriulS
SS 5720 1979 ode of practice for mechanical veutilating and air C 11shy
dirionin bull in building
l3S PR 12814-1 Bend resting for plasric welds
SS PR 12814-2 Tensile testing for plastic welds
SS PR 13067 Appro altesting for plastic welds
BS PR EN I 100-] Vi ual in pection ofplaslic welds
SHEET METAL AND AIR CONDITIONING CONTR-CTORS NATIONAL ASSOCIATION INC (SMACNA) Headquarters 420 I Lafayeue Center Drive Chanlilly Virginia 2051-1209
Mailing Address pa Box 221230 Cbantilly Virginilt120 153-1230
Telephone (703) 803-2980 Fax (703) 803-3732
Accepted IJJdustry Pl3Gtice for Industrial Duct Constnlelion 197 ) i-rchitecmral Sheet kwl Manual ([993)
Comractors Guide lor Modification 10 ooslruerion Colllraets 1993 Ducted Eleclric Heat Guide for ir Handling Ssrerns (1994)
En~rgy ollservatioD Guidelines (1984) Energy Recovery Equipment yslClllS (199l
Fibrou GIns Duct onS1ntClion Standards (1992)
Fire Smoke amp Radiation Damper In tall Guide for HVA Syst ms (1992) Guide t leel Stack 1(95)
HVA Air Duct Leakage Test Manual (19 ) HVA COlllmissioning lvlanual (1994)
H A Duct Construction Standards-Metal amp Flexible (1995) Addendum 01 (Nov 1997)
HVA Duct Systems Inspection Guide (1989)
HVA ySlems-Application (1986) nVAC ByternS-DLlct D ign (1990)
HVi Systems-Testing Adjusting amp Balancing (1993)
indoor Air Quality Manual (1993) tcheu quipment Fabrication Guidelmes (1990)
Managers Guide for elding (1993)
Rectangular Industrial Duct Cons1TUction Standards (19 0) Round Industrial Duct oustmction Standards (1977)
Sei mic Restraint Manual (1991) (wl Appendix E 1993) SMACNA Ma le Index ()fTechnical Publications (1995) Tbennoplnstic Duct CPY ) Construction Manual 1994)
DEPARTME OF THE ENVIRO MENT (Publications Centre) H Stationery Oflice 5 Nine Elms Lane London SWS 5DR
MampEJ 011972 Electrical in tallat1011 in buildings ( ew Editiou)
IampE 0319 Healing hot and cold wat r steam and gas losla1lations for buildings
M amp - No4 1970 Central heating and hot and cold ~ ateT in tallations for
dwelling
M amp ENo100 1971 Mechanical ventilation for building~
ASSOCIATION FOR SPECIALIST FIRE PROTECTlO As ociation House 235 Ash Road AJdershot Hampshire GUl2 4DD
Telephone OJ25221322 Fax 0 J252 333901
lublicalioos Fire Ratcd and moke Outlet Ducrwork An Industry Guide t Design and InSlalla lioll
HEALTH AND SAFETY EXEC TIVE Rose Court 2 Southwark Bridge London SEl 9HS Telephone 020-7717 6000
TWJ THE WELD G TlTUTE Abington Hall Abington Cambridge CB16AL Telepbone 0 J223 89162
Publication DatJ Oil w~ldll1g of lhermopla lics
59
DW154 wciiwlioll for Plastics Ductwork
A -=--DIX
Factors
Specific gravity shy pp = 091 approx UPVC = 14 approx
Some miscellaneous conversion factors
To convert
Length Inches to millimetres Feet to metres
Multiply by
2540 03048
To convert
Millimetres to inches Metres to feet
vIultiply by
003937 3281
Area Square inches to square millimetres 6452 Square millimetres to square inches 000155 Square feet to square metres 00929 Square metres to square feet 10764
Volume Cubic feet to cubic metres Cubic feet to litres Gallons (UK) to litres
002832 2831 4546
Cubic metres to cubic feet Litres to cubic feet Litres to gallons (UK)
35315 00353
022
Mass Ounces to grams Pounds to kiJograms Tons to tonnes
2835 04536
1016
Grams to ounces Kilograms to pounds Tonnes to tons
003527 2205
09842
Volume flow Cubic feet per minute to cubic Cubic metres per second to cubic
metres per second 0000472 feet per minute 2119 Cubic feet per mIDute to litres Litres per second to cubic feet
per second 04719 per minute 2119
Motion Feet per minute to metres per second 000508 Metres per second to feet per minute 197
Pressure Inches water gauge to millibars 2491 Inches wateJ- gauge to pascals (Pa) 2491 I Pa = I ewton per square metre = 10-2 millibars
60
Heating and Ventilating Contractors Association Esca House 34 Palace Court London W2 4JG
Tel 020 7313 4900
e-mail contact Itvcaorguk web site wwwhvcaorguk
Fax 020 7727 9268
DW154 Spccijicutioll for Plastics Ductwork
147 Protection specification Any special coatingpaint Unless otherwise stated all support shall be finishes for protection against hostile manufactured in material as specified in this environments shall be advised by the designer
SUPPORT BEARERS
~ 14 Flg16 Inverted profile
angle I ~lIed steel
channel (alternatives) Fig 15 Profile channel (alternatives)
TYPICmiddotAL VERTICAL DUCT SUPPORTS Flat bar clipStiffening frame Outline ofinsulation stiffening frame or tlanged joint (if applicable) or flanged joint
Stiffening framc or flanged Joint
~~-I ( ee notes 10) I
r--~ -++- ~--4==J===4~---
Fig 17 Vertical rectangular ducts Fig18 Vertical circular ducts
The support bearer which depending on ducti tructural opening size could be either channel or angle section may be ll1ilised in any of the following arrangementsshy
a) To support the underside of a flat bar clip in halves (circular)
b) To support the underidc of either the stiffening frame oftbe flanged joint ofaoy duct section
c) To support either a stiffening frame Or a flanged joint below nsing drop rod srudding
20
DW154 Spediraiml for Plastics Ductwork
Arrangement of bearers and hangers (to be read in conjunction with Table 8 amp 9
wbich list material sizes relative 10 duel izes)
KEY Limits refer to actual duct size - insulation is additional - Typical
attachmentv -Atta hment t strucUlrcI to strucUlrc
I I
I - Flat Bar
I - Drop rod or - utlinc of lllddmg In ulillwn (if
applicable)
Alternative 7 drop rod or rt------------ 1 studdmg q I
I I Rectangular
ii i n 1
Fig 21 Rolled or profiled bearer Limit oncFig 19 Wrap-round hanger Limit 55 DIA
V v Drop rod orAllernaUC 1 1 tudding
drop rod or 1
-- -- 1studding and elded bas 1
I I0 -_
Limit 355 DIA Frg 22 Split clips Limit 1500 DIAFig 20 Flat strap hanger amp split clips
21
DW154 Specification for Plastics Ductwork
6PA deElned in J62 appropriate to the airflow pressure acoustic temperature and corrosion
General
15 ACCESSl SPECTION OPENINGS
151 General These are for inspectionservici ng on 1y
HVCA publication DWIl44 Part 7 - General Section 20 sets out the requirements for access applicable to this specification
152 Cleaningmaintenance Designers shall take specialist advice and then stipulate their requirements for the periodic internal cleaningmaintenance of ductwork and of the consequent need for adequate access for specialist cleaning equipment including the size type and locationfrequency of the actual access openings required
Appendix D sets out guidance notes for the consideration of cleaning access and also makes reference to the HVCA publication TR 17 Guide to Good Practice Cleanliness of Ventilation Systems which covers the su~ject
in greater detail
Note A majority of in tallations in which plastic ductwork is used are considered to have a nigb operational risk potential and provision of access should address this
16 REGULATI G DAMPERS
161 General Balancing dampers and control dampers are elements inserted into an air di tribution system or element of an air distribution sy middottem Balancng dampers permit modification of the air resistance of tbe system and consequently cbanging of the airflow rate Control dampers control tlle airflow rate and may in addition provide low leakage closure of the airflow
The deigner shall specify damper locations taking into consideration that good design practice requires a minimum of five times the diameter or width of the shortest side of uninterrupted flow between plant connections and the damper and select the damper type as
characteristics
1611 Balancing damper To achieve the required distribution of air in the ductwork system at inlets andor outlets for [hi purpose the damper blades are set and Jocked manually in position between fully open and fully closed
1612 Control damper To secure dynamic control of the air now in the ductwork system In thi function the damper will always be power actuated and may require to be modulated between fully open and fully closed and to be capable of taking up any position between these extremes In the fully open position the damper should have a minimum pressure drop In the fully closed position it will not necessarily achieve a complete shut off
162 Types of airflow control dampers Airflow dampers of various types are available for specific purposes as follows
1621 Single - blade dampers Single-blade dampers shall consist of a si ngle pi voted blade cOlllained withjn a casing or section of ductwork The blade shall be adjustable tbmugh a nominal 90 angle by means of a quadrant or similar operating mechanism Where automatic control of the damper is required the spindle shall be extended to enable a powered actllator to be mounted
Single-blade dampers shall have a maximum duct width of 400 nUll and a maximum duct height of 400 mm for rectangular ducts and for circular ducts a maximum diameter of 400 mm
1622 Multi-blade dampers Multi-blade dampers shall consist of a number of pivoted blades contained within a casing The blades shall be
22
DW154 Sedicalirm for Plastics Ductwork
adju table through a nominal 90deg angle simultaneously by intershyconnected linkage or gears connected to a quadrant or similar operating mecbanism Where automatic control of a damper is required a spindle shall be extended to enable a powered achlator to be mounted
There is no restriction on the size of duct in which multi-blade dampers or damper assemblie may be u ed Where dampers are required for blade lengths in excess of 750 mm the blades should be suitably reinforced or supponed 0
individual damper blade should exceed 200 mm in width
1623 Iris dampers Lris dampers shall consist of a nUlllber of radialty interconnected blades which open or close within a casing with duct COlll1cctions The blade shall be simultaneously adjusted by a quadrant or similar operating mechanism
Iris dampers shall be installed as specified by the manufacturers operating and installation instructions where the product is unidirectional with regard to airflow
lris dampers are available for circular ducts only in diameters up to 250 mm (it should be noted that the damper casin i appro)(imately twice the diameter of the duct)
1624 Backdraught dampers Air pressure operated uni-directional rectangular (single or multi-blade) with adapters if fitted to circular ducts
1625 Slide and blast gate dampers A damper [lsed as a shut off facility with an externaJ Lide bousing allowing the blade configuration to be fuJly inserted to fully extended for maxiDlUlll air flow
163 Construction
1631 Materials All products shall be protected against cOHosion as necessary and supplied in a fully finished condition as specified by the designer
1632 Dampers used in low and medium pressure systems The following recommendations apply to dampers forming an integral part of ducrwork with pressure classifications A and B air leakage limits
The dampers shaH be constructed to minimise distortion and prevent jammin in operation Th blade shall be sufficiently rigid to minimise movement when in the locked pOSitiOLl
The blades shall be securely fixed to the operating mechanism All balancing dampers shall have a locking device located on the outsid of the case and shall giv clear indication of the actlwl blad position All penetrations of the duct shall be fitted with suitable seals where necessary
1633 Dampers used in high pressure systems Regulatino- dampers used in duc[work sy tems to pressure cJassification C shall meet tbe construction requireshyments specified in 1631 and 1632 with operating mechanisms out of the air-stream
1634 Proprietary types of damper The use of any specific type of proprietary damper shall be confirmed by the designer In all cases proprietary dampers shall meet the relevant requirements of thi specification
1635 Damper casings Duct damper casings hall be constructed to meet th mllllmum
23
DW154 SpeciJimlioll for Plastics Ductwork
leakage Iim its sp cified for th c1uctwork ystem to which tbey are installed
In order to apply the square metre leakage calculatio as detailed in DW143 A Practical Guide to Ductwork Leakage Testing the reference casing area ball be taken as the perimeter ize of lh damper IDultipli d by the equi alent length of Imetr eg an 800 mm x 400 mm duct damper hall have a surface area for casillg leakag p donnan calculated as follow (2 x 08) + (2 x 04 x I
=24m2 casing area
Other pelforlllance ancl rating test methods for damp f and valves are specified in ISO 5129 and BSIE 1751 and are referenced belm a) Leakage past a closed damper
alve BSIE 1751 b) low ratepre sure requirement
characteri t cs BSIE 1751 c) Operational torque le ring
BSEN 1751 cl) Thermal transfer testing
BSIEN 17 I e) Reg nerated sound power levels
ISO 5129
164 Installation Dampers shall be imaalled in accordance will) any re Ievant ISO EN or British Standard 10 aJ bUT lcling regulation and national code of practice as well as the manufacturers recommendations
17 FIRE DAMPERS AND INT MESCENT SLEEVES
171 General Damper or sleeves arc requiTed on duct y~telll where the designer has -tjpulated the
duct wiU penetrate a fire compartment in the majority of application tbermopla ti ductwork is ugtecl where contamlDated corro ive or otherwise exceptional fumes are concerned it is preferable to use tire damp r which are externalJy mounted ie of the intmnescent operated crush typ
24
72 Fit-e rating The damper assembly should have a fUT
resi tance ratin o equal to that of the fir ban-jer it penetrate and ball be fire tested and rated to the timetemperature curv of B 476 Part 20 and 22
173 Intumescent sleeve At the time of writing this specification qualified test results were available for rectangular dampers and circular dampers up to 55 mm diamet r Manufacture have indicated that they are able t provide speci fications for other size and diameters This infonnation should be confirmed b th de igner Various type are available includino
tho e incorporating ruechanical closing plate and those operated anI by expanded iJllUme c nt media
In all ca es fire damp rs and intnmeBcen leeves shall be supplied and in taUed in
accordance with the manufacturer iJlStructioos and COSHH a essm nt
174 Other types Fire dampers of mious types are availabl for specific purpose~ ee HVCA publication DW144 The de igner should )lot (hat materials for con lt1Jction bould be uitablc for the par1icular application
ALL C SES FIRE DAMPERS AND fNT MESCENT SL _VES SHALL HE S PPLTED AND INSTALLED IN A ORDA CE WITH Tf--IE MANUshyPACTURERS STRUCTTONS AND COSHH ASSESSMENT
18 FLEXIBLEEXPANSION dOINT CONNECTIONS
181 General ploperties Tbe material u ed for flexibleexpan ion iojnt~
mu t meet the design r requirements for temperature air pressllrelfe resistance applicable to pl astic duct sy tem vibration and noi e br akout when incorporated into a jointconnection and shall comply ith lh standard of air-tigbtne specifi cl for the duct work sy tem of which it fOlms part (See Figs 23 24 5 26 27 amp 28 for typical con truclion clelai Is
DW154 SJecilimtol for Plastics Ductwork
Expansion joints
Fig23 Moulded bellows type (rectangular and circular)
Fig24
~F aiblc sleeve
__ liding sleeve
~~~~
Sleeve type (circufar)
Fig 25
AIRFLO
COnlinuou~
weld~
Flexible Iceve
PV A HOWN pp SE BACKING FLATS AS FIG 2
Sliding lee c Co1linuou
weld
Flanged sleeve (rectangular and circular)
25
DW154 Specificatiol for Plastics Ductwork
Flexible con ections
Fig 26 Flexible sleeve with clips (UPVC and PP)
--__ Flexible I eve
I
I
I CODn clioD to plant ~
Band clip
Fig27 Welded flexible sleeve (UPVC only)
Plastic)sed PVC slceve ~-- onll11uo1sly welded
onrreclion to planl ~
Fig28 Flanged flexible connection (UPVC and P )
t sp dally moulded flexible flanged connCClitlll
boil
C)nneclion to plant ~
26
DW154 Specificotiol for Plastics Ductwork
182 LOClt1tion Flexible joint are typicltllly lIsed at building expansion joint and fan inletsoutlets Any others required should be indicated on the de ign drawings Care should be taken to maintain alignment across jointsconnections
183 Length Flexible Jomts shall be kept as short as pra middottieable above a minimum eft ctive length of SO mm In no ca e shall a flexible joint exceed 250 mm in lengtb
184 Connections to rectang a ducts With flanged rectangular connections Ule tlexible material shall be held in pLace with flat pIa tic strip of not less U1an 6 mm thick ltlttached to the flanges using uitabJe fixings The more heavy weight type of fleAible mateLial may also be obtained formed into a channel ection with corners fitted to give a neat air tight j int For pigot connections the Be ible material shall b held in place with flat pIa tic trips n t less than 6 mm thick
t 85 Connections to circular ducts With tlanged circular connections the flexibl material shall be held in place with flat plastic backing strips or proprietary clip bands with screw or toggle fast ners
186 Welded flexible connections (Rectangular and Circular) Where the parent and llexibl material are from imilar ba ed products they can be joined to the duct u ing the welding method described in Section 823
19 PROTECT VE FINISHES
191 nles otherwise stated all ductwork shall be mallllfactured in mat fial as pecified in tbis specification Any special coatingpaint fmishes to be provid d by the duct work contractor sball be advisd by th de igner
20 CONNECTIONS TO BUILDING OPENINGS
201 Fanning and finishing building op nings are not the repoJlsibjlity of the duftw( rk contractor and the note that follow are for guidance purpo e only
2011 Openings in brick block or concrete walls shall have inset frames to provide a suitable means of fixing grille louver masking flanges or the tlanged ends of ductwork The illset frames shall be conslnlcted to maintain the structural int grity of the wlll and where applicable cavities shall be suitably lined
2012 Openin s in dry linino partItIons shall have inset frames a 2011
2013 Openjngs in cladding walls and roofs shall have flaoged leevesframes to provide a suitable means of fixing a 2011
2014 Horizontal and vertical opening xposed to oLltside atmo phere hall
be provided with a suitable weathering fini h at the external face especially where profiled cladding is used
2015 Timber framed op nings are not permitted In fj re compart ment barriers
202 Ductwork connections to building openings hall have a flange of suitable profile to permit practical fixing to the openillg frame In selecting the profile consideration shall be given to Tabl~s 2 and 10 in this specitication relating to duct ize and rating Gasket strip or sealant shall be ltlpplied between the tJaoge and building op ning frame
21 DISCHARGEEXHAUST TERMINAL
21 Tbese shall be vertical open ended and designed to meet and comply with current r gularions on contaminated flue The designer hall ensure that the de ign and perf rmance i suitable for its intended purpose Examples of some typical terminal designs are SbOiD in Figbull 102 10 bull 104 amp 105
27
DW154 SpedjimioTl for Plastics Ductwork
22 THERMAL INSULATION
221 The provision and application of thermal insulation to ductwork is not the responsibility of the ductwork contractor
222 Where ductwork is required to be preshyinsulated the specification should be agreed with tbe designer
223 Where the temperature of the air within the duct promotes condensation on the exterior surface of the duct and cause moisture penetration througb the thermal insulation vapour scaling may be required and in this case the most important requirement is to limit penetration of the seal
The extent of any vapour sealing of ductwork thermal insulation and the support method to be u ed must be clearly pecitled in advance by the designer
224 For detailed information on the thermal insulation of ductwork reference should be made to BS 5422 1990 which covers the specification for thermal insulation materials on pipes ductwork and equipment (in the temperature range -40degC to +700degC) and BS 5970 1992 which is a Code of Practic for Thermal Insulation of Pipework and Equipment (in the temperature range -lOOdegC to +870degC)
23 FIRE RETARDANT FINISHES ON PLAST C DUCTWORK
231 The designer should note tbat ductwork constructed to DW154 has no teted fire rating or information see Appendix C
24 REINFORCEMENT OF DUCTS WITH GRP LAMINATE
241 General Where ductwork is required in larg T izes than are covered by Tables 2 4 6 amp 7 or with the increased strength sometimes necessary for industrial use external reinforcement is normally pwvided by applicatioD of glass fibreresin laminate
GRP systems will bond satisfactorily with standard UPVC sheet but for pp it is
nece sary to use a specially prepared sheet with a glass fabric backing incorporated dOling manufactllfe
The detailed techniques of fabrication using GRP are outside the scope of this speci lcation but the following notes are offered for guidance of ductwork fabricators
242 Materials
2421 Quality The laminate is made up of polyester resin complying with BS 3532 and glass fibre complying with BS 3496 or BS 3749 The nominal ratio of resin to glass fibre should be 7030 by weight
2422 Minimum properties The laminate shall comply with the followiog mini mum pbysical properties
Tensile strength - 70 MNm Tensile modulus - 7 Gl m Flexural strength - 140 M Im Bond strength (hetween laminate and substrate Not less than 7MNm Bmcol hardnes Not le s than manufacturers specification
The GRP reinforcement educe the expansion of the parent material but the resultant stre ses arc well within rhe strength of the bond However the Iinear thermal expansion curve shown in Figs 34 amp 35 will serve as a guide
Surface resistivity electrkal propcltles and acoustical propertie are similar to the relevanl unreinforced materials The fire retarding properties of GRP may be improved by the use of specialisl laminating resin
2423 Forms available GRP Laminate should be built up from the separate materials ie resin aod glass fibre in the form of chopped
I strand mat or spray ravings
28
DW154 Spcification for Plastics Ductwork
2424 Workshop conditions Polyester resuls are sensItIve to lmperature and the workshop hould b maintained at a temperature of herween 20deg and 25degC HiOh relative humidities and damp onditions should be avoided A good rate of air change must be pro icled pJeferably by m chanical ventilation
2425 Storage of materials Resin and urin o agents shouJd be stored in dark cool condirions away from the working area and in confonnit with statutor requireshyments for tJle middottorage of flarmnable liquid Because of Ule Limited torage lif of the unmixed resin and curing a eot mal lials ~hould be ch eked before use to enLlfe that they are within the manufacturer pe ified sh If life (usually ix month from the dm of manufacrure)
Glass fi re should be stored separately und r clean dry conditions
243 Surface preparafon
2431 UPVC To achieve the specified bond strengtll the urface to which the GRP is applied mut first be thoroughly cleaned and then etched either by mechanical means or by the use of a suitable solvent
2432 pp with glass fabric backing To achieve the specified bond middottrength the fabric backing must be thoroughly impregnated Witll resin
244 Mixing the materials for use The re in 1 a three part mix compri lng base I sin hardener and accelerator The manufactur rs pecj[ied proportions are critical and th llUxmg sequenc pecified must be meticulously foUowed
The resin has a very limited life after mixing and before u e It is dependent on the characteri tics and bulk of th resin the alllount of hardener the degree and method of acceleration and the workshop onditions
245 Methods of application
2451 General The mixed resin may be applied by hand or b pray c1epoition The operation must b completed within the gel time of th y tern and tbe laminat fully cOI1olidated to achi v the phy ieal properties pecified
2452 Hand lay-up The duct surface i coated by hand with resin Llsing a brush and a mar of gla fibp orked in until full consolidation achieved Th proc is repeated untiJ th requird thicknes i obtained
2453 Spray depo Won The duct surface is coated WiUl re in by spray gun with the chopped glass roving added through a separate nozzle The full thickne i obtain d in layer with con olidation of each layer by hand roller
246 Construction
2461 General M ini mum COllst ructional requireshyments are pe itied ill Tabl 10 for rectangular and Table 1J for circular dUClS
2462 Joints and stiffeners Fig 29 30 31 32 amp 33 hoI TOSS
joint and tiffener for reinforced UPVC and PBPP duct
247 Worki g practices The fabrication of ductwork pecifiecl ill thi document i not affected by the addition of GRP
29
DW154 SfJcdJicatiOt for Plastics Ductwork
Table 10 Minimum constructional requirements shy
Longer Side Minimum Sheet Thicknes and
GRP Reinforcement
UPVC FBIPP 1 2 3
mm mm mm Up to 1000 3 plus 3 plus
06 kgm2 06 kgOIl GRP GRP
1001 to 2250 45 plus 3 plus 06 kgm 12 kgm
GRP GRP
2251 to 3000 45 plus 6 plus 12 kgm 12 kgm
GRP GRP
Cross Joints
UPVCFBPP 4
mm socket amp spigot
as Fig 30 or flanged as Fig 29
75 x 9 flange welded on both sides as Fig 29
75 x 9 tlange welded on both sides as Fig 29
rectangular GRP reinforced ducts
SlifTeners Maximum Spacing Between
JointsSljffeners UPVCIFBIPP UPVCFBPP
5 6 mm mm
75 x 9 flat 800 as Fig 31 or
50 x 50 x 5 plastic or MS inverted angle as Fig 32
or tormer as Fig 33
75 x 9 flat 600 as Fig 31 or
50 x 50 x 5 plastic or MS inverted angle as Fig 32
or former as Fig 33
75 x 9 flat 600+shyas Fig 31 or 50 x 50 x 5 plastic
or MS inverted angle as Fig 32
or former as Fig 33
Note 1 On rectangular duct up to 400 mm longer side no stiffeners are required 2 Applies to Tables 10 amp I I For COlJstructional operating temperature limits refer to Part 2 clause 5A 3 Tables 10 amp II apply to all pres ure classes up lo ]500 Pa
Table 11
Diameter
1 III
lJp to 1000
1001 to 1750
1751 to 2500
Minimum Sheet Thickness and
GRP Reinforcement
UPVC FBPP 2 3
mm mm 3 plus 3 plus
06 kgm 06 kgm GRP GRP
45 plus 3 plus 06 kgm2 18 kgm
GRP GRP
6 plus 6 plus 12 kglm2 18 kgm1
GRP GRP
Cross Joints
UPVCFBPP 4 III
socket amp spigot as Fig 30 or flaoged as Fig 29
75 x 9 flange welded on both sides as Fig 29
75 x 9 flange welded 00
both sides as Fi 29
inforced ducts
Maximum Spacing Between
JointsStiffeners UPVCIFBPP
6 mm 2400
800
600
Stiffencrs
UPVCFBPP 5
mm 50 x 9 flat as Fig 31
75 x 9 flat as Fig 31 or former as Fig 33 75 x 9 tlat as Fig 31 or t()rmer as Fi 33
ote On extruded tube tip to 600mm diameter no stiffenergt are required
30
DW154 Specificatioll for Plastics Ductwork
G - Cross joints and tiffeners
Fig 29 Flange Joint Fig32 Stiffener shy inverted angle
M artiPfCuQkbdd erttpObri) Wl111 RP tlddtlt
_- GRPloliu] lh~
Fig 30 Socket and spigot joint Fig33 Stiffener shy use of former
Fig 31 Stiffener Flat
I Pv FlPP ~ ~lmJaDUA1) d
OMrlQ rrnall 1( tQlS
25 STANDARD COMPONENT DRAWINGS AND ABBREVIATIONS
251 The illustrations in this section not only highlight where applicable geometric limjtations for the de ign and manufacture or ductwork components but also recommend
standard drawing representation terminology and abbreviations for both duetwork components and some of the more commonly used ancillaryplant items
252 Designers and surveyors should note that bills of quantities should provide a full description
3)
---
v
DW154 Spcc(fim(ml for Plastics Ductwork
Fig 34 Linear Thermal Expansion
u c 0 N ro 0)
b 0)
S
sect0
5 oS cl) 0)
~
on ~ ltl
c U
-30 -20 -10 0 10 20 30 40 50 60 70 80 90 TEMPRATURE C
~ V
-
~~c_ ~
~V
V ~
-7 ~
-- ~V ----
v
-6
+14
+12
+10
+8
+6
+4
+2
0
-2
--4
ig 35 Typical Design Stress tor UPVC and P
7
6
r shy 5E
-c E----0 4t) VJ 0)
ci5 0Jl 3
~
0)
Cl
2
1
o
UPVC
1
000
1
1
pp
- r-- shy r----- shy - t--shy I
__0
-30 -20 -10 0 10 20 30 40 50 60 70 80 90 TEMPERATURE C C
Note Figso 14 amp 35 shaded area refers to GRP reinforced duct
32
DW154 Speciicfltirm for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - REC ~NGULAR
Splilt~r Posilion W-mm pliucr
A B c 40]--QOO 1 W - -
601-1000 1 W4 Wf2 -
1001-1800 3 WI W3 W2
FIG DRAWING DETAfiS
tU]36 ATI Straight Duct with socket and spigol joint
rn [037 Straight Duct with flanged joints
[I []38 Straight Duct with flanged joints
rkJ Short Radius Bend
39 Applies to any augl and for duct up to 400 n11n wide
Minimum (I1m31 radills = 100 mm
Medium Radius Bend (a illustrated)
[kJ Applies to any angle
40 Long Radiu Bend Similar but radius = W
Throlll radius = W2 Applies to any angle
- Short Radius Bend with plitlers
I -shy -shy u co - t lt Li--_ 41 t 0 ~ I I I
~ I
L 1W
Minimum waal radius = 100 mm Splitters not required in bend angle less than 45deg
42 QJ1 Square Bend with turning vanes ij
3
DW154 SP(L~ficatioll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - RECTANGULAR
FIG DRAWl G DETADS
43
~
I v
L L Radius Tee with internal deflectors
44
~ Radiussed Twin Bend
45
Imiddot
er Swept Branch
46 U-
Sqoare Tee with Turning Vanes
47
~ f
Breeches Piece
48 0 y l Piece
34
DW154 Specificatioll for Plastics Ductwork
STANDARD COMPONENT RAWINGS - ECTANGULAR
55
54
51
50
53
52
49
FIG
~MX
RAWlNG
DmiddotMAX
EfjMAX
Minimum throat rndius = 100 mm
Rectangular shy Round Transformatioll
Eccentric Taper 225deg max in either plane Spliller are required for angles greater than 225deg and hould bi eet the angle between any side and duct centreline
DETATLS
Angled Offset
OUset Taper Splitters are required for angle greater than 22 0
and shoold bi eet the angl between any side and dUCI centrelinc
Mitred Offset
Concentrk Taper 2250 max in ither plane SpUtters are required for angle greater than 225deg and should bisect the angle between any side and duel c ntreline
Radiussed Offset
35
DW154 Splcilcuthm for Plastics Ductwork
STANDARD COMPONENT DRAWINGS ~ RECTANGU AR
Branch ducl DimCllsions widlh (W) (A)
urnl mm up lO 200 75
300 100 400 125 600 150
Ocr 600 200
FIG DRAWlNG DETAILS
56 poundplusmni~~ Rectan~lar - Flat Oval Transformation
57 [ Square Branch
58 er Angled Branch
Branch dUCI Dimensions wfdth (W) (A)
[- mm mm59 3shy Shoe Branch Up (0 200 75
--shy AIshy + 300 100
400 125
450 MAX 600 150
Over 600 200
Branch duct DimensIOn
rP X width (W) A)
60 - 1--shy _
~ mm mm
Bell Mouth Branch pto 200 75 300 100 t 400 125
600 150 Over 600 200
0=0 61 -
~ Bell Mouth
- shy T 4-5deg M x
--I 1-shy
TJ
62 X I ] I
Tele-scopic Joint I Illustrated with flangeL
X63
SBD Single Bladed Damper
36
---
DW154 Spedicatioll for Plastics Ductwork
STANDARD OMPONENT DRAWINGS - RECTANGULAR
DRAWING DETAILSFIG
64 on-Return DamperNRD shyshy
shyXbull
Multi-Leaf Damper Can be piggoted or flanged oppo cd or parallel blade
Alternative controls areshy
q p [gtshy
J HD65 Hand
~MD otori ed
PO Pneumalic
L-lt
l 13G 66 Blast Gate DamperX X
FireSmoke DampersSleeves
211r Ratinggtshy----
L_-
---
----
r----
Ir-- shy
IL- _-l
2hr
With i tallation frame
67 41 r Rating
4hr
Smoke damper SD
Intumc cent Sleeve L-d
37
DW154 Specijicutiolt for Plastics Ductwork
FIG
68
69
70
71
STANDARD COMPONET DRAWINGS shy REC ANGULAR
DRAVING DETAILS
gtshy Access Openings
AP 6 Access Panel - Rerno able
w [ ~ Access Door - Hinged
I ~le Inspection Cover
le -I reg -lt
~X X Flexible Connection
~ Drop Cheeked Radiussed Twin Bend
U Drop Cheek Bend
I
72 Air Flow SymbolX
38
DW154 Specifim[ioll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - ECTANGULAR
FIG DRAWING DETAILS
73
74
75
76
77
Q
Q
rp---t
~
V- I Ir---I
JL --11
THE ABOVE DETAILS TYPICAL PLENUM
Air Terminal Plenums
Plenum with side connection
Plenum with top connection
Cover plate with connection
Special plenum with connection
elescopic conn ction in direction of air flow
39
DW154 SpecijicotiOll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG
78
79
80
81
DRAWING
-23~---pound3-(MALE) (FEMAJE)
-t=j--_j(--d-shy
--L
~ THROAT RADI S= D AS T NDARD
e ~
THROAT Rjf)lU = D A MU)
DETAILS
Straight Duct With male and female connectors
Straight Duct With flange joint and slip joint
Bend MouldedIFormed Applies to any angle ego 30deg45deg60deg90deg Medium radius bend as illustrated Long radius similar but throat radius 0
Segmented Bend 90deg four section minjmum as illustrated
Other Angles 60deg = 3 sections 45deg = 3 sections 30deg = 2 sections
I
i
40 shy
DW154 Speciicafinll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG DRAWING DETAlLS
82 Segmented Twin Bend Radius = D2 max
May also be fabricated from tube
83 Equal Tee MouldedIFormed
84 -~ 1in Bend MouldedIFormed
85 Taper Concentric 1 0 as iUu trated Eccentric 30deg iJJcLuded angle
86 Short Taper
41
DW154 SpcUicatol1 for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG DRAWING DETAILS
87 30 max Offset
Angle Branch
Bran h dUCI Dimcnsions dia (D) lA)
Shoe Branch mm mm 88 Cl
Off rectanguJur Up 10 200 75 lOO 10 400 125
- 00 150 Over 600 200
Bl1IllCh duct DimenlOns din (D) (A
~-$a-Conical Branch mm mm
89 Also acceptable with Up 10 200 r
full conical surface 300 10
400 125
END VrE -shy 600 150 Over 600 200
90
m 75
100 12 150 200
mm Up to 200
_ 300 400
600 Over 600
iUtred Branch
Shoe Branch
J-L----U ~ Bell oulh Branch
ENDV1EW
93
92
91
42
DW154 Specificatiol for Plastics Ductwork
STANDARD OMPONENT DRAWINGS - CIRCULAR
FIG
94
DRAW G
I
~ 30deg 090deg
Breeches Piece
DETAILS
95 amp-----~ Blank End
~-----p Multi-Leaf Damper Can be piggolcd or fianged opposed or parallel blade
Alternative controls areshyri=-+- L-T~
I
---
LT~
I r- -
-+1
J HO Hand96
bMD Molori cd
PD Pneumatic
tl-shy bull
Single Bladed Damper 97 ~ saD
on-Return Damper Vertical application only 98 m~D
43
DW154 Sf1tcificatioll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG
99
100
101
102
DRAWING
$ I-
2hr
1 4hr
SD
~v I I
CO TINENTAL COWL
DETAILS
Iris Damper
Fi reS moke Dam persSleeves
2hr Ratillg
With installation frame
4br Rating
Smoke damper
Intumescent Sleeve
Access Openings
Access panel - removable
Access door shy hinged
fnspection cover
Discharge Continental Cowl
44
DW154 Sp(Cii(ltJll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
DRAWINGltIC DETAns
-
I
I
~
I I I High Velocity Discharge Terminal 103 I
I
I I
J I I 1 ~--
Offset Stack Discbarge Terminal 104 1
~ I e --(-
I
N
I
I
I~
I I Vertical Oischarge with Weather Cowl 105 I
--1--1 I
I
GAPI I
RTl AL DISC) lARGE WITH W ATIIER COWL
45
DW154 SpecUicatoll for Plastics Ductwork
STANDARD COMPONE T DRAWINGS - PLA TEQUIPMENTIMISCELLANEOU
FIG DRAWING DETAILS
106 ~~~ Rectangular Attenuator
107 ~- Circular Attenuator
108
~ Beod Attenuator
109 J ~(f) Heating Coil
110 J ftte Cooling Coil
III Jc[ Electric Heating Coil
112 X F
Humidifier
113 [H XX Axial Fan
114 ~fB1famp Noo-standard Ductwork Cross hntchillg (of any separate type) indicates by reference to a key any non DVil54 ductwork system
115 2llIIIIJIIIIIll Flexible Ductwork
46
DW154 SJeCUicll(iol1 for Plastics Ductwork
TABLE 12 - STANDARD ABBREVIAT ONS
ABBREVIATION FLL
AD Acces Door
AFF Axial Flow Fan
AHU Air Handling nit
All Aluminium
AP Acess Panel
AT Attenuator
AV Air enninal Unit
BE 81ank nd
BQ Blast ate Damper
CC Cooling Coil
CF Centrifugal Fan
CTA Cross alk Attenuator
CVU Constant Volume Unit
DP Drain Point
EEC Electric Heating Coil
El Expansion Joint
FAl Fresh Air Inlet
FA From Above
FB From Belo
fBPP Fabric Backed Polypropyl-ne Sheet
Flexle Flexible Connection
lexfD Flexible Du t
C False Ceiling CO an oil Unit
fD Fire Damper
FFL Finished Floor Level
FJ Flanged Joint
FOAM Rigid Polyurethane Self xtinguishing Foam
FOB Flat on Bottom
FOT Flat on Top
GAM Galvanised after ManufacttrJc
GRP Glass Reinforced Plastic
GSS Galvanised Sheet Steel
HC Heating oil
HD and controlled Damper
HH Hand Hole
HL High Level
HVD High Velocity Discharge
IC Inspection Cover
ID lri Damper
IFS Intumescent Fircleevc
47
DW154 Specification for Plastics Ductwork
TABLE 12 - STANDAR ABBREVIATION CONTINUED
ABBREVIATION
IU
L
tv1D
MS
NRD NTS
OBO
OE
PHD
PD
PP
PP
PRD
PVC
RFC
RSC
R
SBO
SO
S1 TST
SSL
TA
TB
TO TJ
TP
TV
TV
OS
UPVC
S
V
VAV
50 RSA
FULL
Induction Unit
Low Level
Motor controlled Damper
Mjld Steel
on Return Damper
at to cale
Opposed Blade Damper
Open End
Parallel Blade Damper
Pneumatic controlled Damper
Polypropylene
Self xtinguishing Polypropylene
Pressure Relief Damper
Polyvinyl Chloride
Rolled Form Chamlel
Rolled Steel Channel
R fUnit
Singl Blade Damper
Smoke Damper
Slip Joint
Stainl t el
tructural Slab Level
To Ab vc
To Blow
Top Down (In Direction of Flow)
Telescopic Joint
Test Point
TU111iog Vane
Top Up (In Direction of Flo )
Voles Otherwise Stated
Unpl3sticisecl Polyvinyl Chloride
Underside
Ultra Violet Light
Variable Air Volume
Rolled Steel Angle (Vith Size)
48
DW154 SJeriiflllioll for Plastics Ductwork
A2 DUCT PRESSUREAPPE DXA Ductwork con truct d to DWIl54 will bebullbullbullbullbullbullbullbullbullbullbullbullbullbull
Air Leakage From Ductwork To be read in conjunction with DW143 A practical guide to Ductwork Leakage Testing
CAUTION As highlighted ill both this docul1lenr and DW14 I lot ellough emphasis can be placed 01 the fact that except for high pressure class C the much more stringent ductwork constructional standard brolght about b the general acceptance of DW154 have irtlally negated the requirement for leakage-testing It is essential lO realise lhat except where it is mandatory this doclllllelll is nOl an endors ~lIlent of the rourine testing of ducts bllt purely a guide to outline the procedures for cononnity with the air leakage limits ill Table l Where the specified methods of assembly and
A3sealing of dlcls are u ed a vi ual inspection wil ordinarily sl~fll e for ver(iatioll of a well engineered and a ceptahfy airtight COl1strucrioll WHERE NOT MANDATORY DUCT LEAKAGE TESTING IS GENERALLY AN UNJUSTIFIED AND SUBSTANTIAL EXPENSE
A1 INTRODUCTION L akage from ducted air distribution systems is an Lmportant consideration in the design and operation of ventilatjon and air conditioning middotystems A ductviork t)ystem tbat ba limited air leakag within defiucd limits wiH cnsUft
that tile design characteristics of the sytem can be maintained It wilJ also ensure that energy and operatLonal cosb are maintained at optimum levels DucLwork constlucted and Ulstalled in accordance with DW154 should minimise a level of air leakage that it) appropriate to tll operating static air pre sur in tile system
A4However it is recouuised that tbe environment in wtJich middotystems are installed is not always conducive to achieving a predictable level of quality in term of system ajr leakage and it is therefore accepted that designer may sometimes require tlle ystem to be tested in part or in total It should be ecogni ed that the testing of duct systems add a ignificant cost to the installation and incur some extra tjm within the programme (Se 47 and 64 re mandatory te-sting)
manufactured to a structural standard that is compatible with the system operating pressure There are three classes of duct con truction to eorre pond with the three pre ure clas meations Class A Lo pressure ducts suita le for a maximum positive operating pressure of 500 Pascal and a maximum negative pressure of -500 Pascals Class B IVledium pressure ductmiddot suitable for a rnaxilnuJJl positive operafjn o pressure of 1000 Pascals and a maxllnum negative pre sure of -750 Pa cal Class C High pre sure ducts suitable for a maximum po ilive operating pressur of 2000 Pa cals and a maximum negativ pres ur of -750 Paltcals
LEAKAGE FROM DUCTWORK Leakao-e front pia tic air ducts occur at the joint~ and is therefore proportional to the total surface area orthe du twork in th system Tb level of leakage i imilarly related to tIle air pres ure in th du t system and whilst there LS n precis formula for calculating the level of air los it i generally accepted that leakage will increase in proportjon to pressure to rbe pOvver of 065 The effect of air leakage from high pressure velocit ductwork is critical tn terms of system perfomlan dege energy consumption and the risk of high frequency noise as ociated with leakage These problems are le critical with medium pressure 10 ity systems but should be con idered Low pres mevelocity ducts present the lowe~t
ri k in tenn of tbe effect of leakage on the operation of the s stern
SYSTEM LEAKAGE LOSS As there i no di ct relatLonship between th volume of air conv yed and the surface area f the ductwork sy tern required to match the building configuratmn it is difficult to express air leakage a a percentage of total air volume Similarly the operating pressure will vary throughollt lh 3 system and a leakage is related to pre me the calculations ar comple However it is generally ac epted tbat in typical good quaJjty systems the leakage from
49
DW154 Specificatioll for Plastics Ductwork
each class of duct llnd r operating condition will be io the region of CIa S A low pressure 6 Clas B medium pres un 3 Clas C high pressure 2
A5 SPECIFYING AIR LEAKAGE TESTING Re peeting both the co -t and programme implications a sociated with te ling du 1 for leakage the designer may for example indicate that a particular system is te ted as follow
a) High pressure ducts - all tested b) Medium pr ssure duets - 10 of the
ductwork shall be s eet d at random and tested
c) Low pre sure - unte ed In any case where a random te t i elected for medium pre sure ductmiddot the followin c1au~e is suggested for inclusion by the de ign r
The designer hall elect at random a maxirnwlI of 10 of the dUCl system to bt tested for air leakage The duct hall be tested af the pressure recommended in Table J3 for the assifi atiol for the ectiol1 of the ductwork that is to be tested The tests shall be carried Ollt as the work proceeds and prior to the application of thermal insulation In the event of test failure of the randomlY selected section the designer shall have The right to select two La1her e tiolls at random for resting Where succes ive failures are identified there shall be a Tight to require rhl COl11raCWr 10 apply remedial attention to the complete ductwork system Th contractor shall provide documented eviden e of the calculalions used to arrive (1
the allowable 10 I for the section to be tested and the client or his agent shall willess and sign the results of the test
able 13 Air leakage rates
Maximum leakage of duct work Static
prcssUft Low-pressure edium-prc-sure I Iigh-prebull me diJfercntial Class A Class B Class C
1 2 J 4 Pa Litres per second per quare metre of surface area 100 054 018 ZOO 084 028 300 110 037 400 132 044 500 153 051 600 058 019 700 064 021 800 069 023 900 075 025
1000 080 027 1100 1200 1300 1400 1500
029 030 032 033 035
1600 1700 1800 1900 2000
036 038 039 040 042
Note Recommend d mean test presures are highlighted iD bold type with the actual selection being left to tll test operator
50
DW154 Sfeeiieaioll for Plastics Ductwork
A9
A10
and air leakage classification for the y em under test
DESIGNERS CALCULATIONS The designer can middotaJculate with reasonable accuracy the predicted total loss from a ystem by
a) Calculating the operatin presure in each ection of the sy tern
b) Calculating the surface area of the ductwork in each correspondin pre lire s ction
c) Calulating the allowabl~ los at the operating pressure for each ection of the system (see table 13 for allowable leakage figures)
VARIABLE PRESSUR S IN SYSTEMS De igner can achieve significant co t saving by matchina operating pressures throughout the system to constmctional standard and appropriate air leakage testing eO the practice of specifying construction tandards for whole duct sy tems based on fan discharge pre sure may incur unnece sary costs on a project For example ome large sy terns ould well be classiC ed for I akage limits as follows
Plant room risers CJas C Main floor distriblltJou CIa B Low pre sure outlets Cla A
A6 SPECIAL CASES There may be ~itLlations on a project where circumstance dictate thal pecial consideration be given to containing air loss s eg a long mn of duclwork may incur a di -proportjonate level of air 10 s In ca es such as thi example the designer can specify an improved tandard of airtighmess ie 80 of alJo~able 10 s for la B Ju ts The designer sbould not specif a CIa C t sI at CIa s C pressure for a CIa s B ducl
A7 SUGG S ED RANGE OF TES ING
A8 TESTING OF PLANT ITEMS Items of inline pJant (eg Fig 106 to 115) will not normaUy be included in an air I akage test The dllctwork contractor may indud such itelllS in tbe te t jf rh quipm ot has a certificate of COnfOlnlity for Ihe pres ure clas
bull High pressure duct bull Medium pre sure ducts bull Low pre sur ducts bull Exposed extract syst ID bull Ceiling void extract
systems bull Secondary ducts from
VAV or fan coil units bull Flexjble duct bull Final connections and
branches to grille and diffusers
100 test See A5 Untested UDt sted
Untested
Untested Untested
Untested
SI
i
DW154 SJecijicafion for Plastics Ductwork
ig 116 Permitted leakage at various pressures
Leakage in litres per second per square metre duct surface area
Vgt
o ltgt 0 ltgt N
ltgt Cgt
0 0 cc
0 0
~
g =
g ~
c 0
J
ltgt 0 I
~ ] tn
ltgt ltgt
In ol
~ 0 ~ 8 ~
~
c ltgt ltgt
~ CJ
~ ~ ~ ~ 8
0shyij
~ ~ ~ t
ltgt ltgt 00
l
~
~ Q
c C
~ rshy
e ltgt
I 1
I Cgt ltgtv
c Co ~
~~ ~ 10
I
0 Cgt
fJshyq 410 ) 1 ltgt
ltgt N
~ shy ltgt ltgt
~ I 1
c
52
DW154 Specificatio for Plastics Ductwork
Example of a completed test sheet Test No
General
Name of job N~ jC43Pt(r2lef Building Repound ~(~~0
Part 1 - Physical details
a Section of duct work to be tested ~(diffPIfff~el1f3rd Floor
b Drawing Number g91~~ c ssure aSSJ L atlOn V~Jl~IRfYgtg~~lPre Cl T Class C
d Test static pressure -(9 raErq~ ~~~~-~~J~~~ ~~ ~~~~ll
Leakaoe factor 9~-tre3$ecMz I OM REFTOTABLE 13)e b bullbullbullbullbullbullbull
f Surface area of duct under test Q~tJJItetre$ CPROMCALCU TIO BELOW)bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull ampampamp bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull
g ]Vlaxi mum permitted leakage -~ (~i~~0 ~~r~~ ~~~l-~-11~ ~~~Q
Part 2 - Test particulars
a Duct static pressure reading 9QFt~q~ ~ middot~~~1 ~~
b Manufacturer and type of liow measuring d vice (-~~~cJ~Y-9Q7EYg c Range of measurement of now measuring device QtP)OQ~(e~~~0I~~~~1~I~ ~~~~~~W~
d Reading of flm measurin o device pmiddot IFROM RIO)ftscag ~
I (DERlVED [ROM CHART SUPPUED WITH RIG US 0 ud)1e Interpreted air flow leakage rate ~(~~~f~~~ (~l~~~~~~~~~~~~~~~~~I
f Duration ~~~~~norn~allY l~ lnil1Ut~~d~~~ it1~ W~ Date of test ~(lITled ut by Wltll s ed by ~ ~
(~lJ MIJLrr) (Si~rrfltJUYJ
Printed Name 1~g0f~ Printed Name ~~Y~9~ and Company 7jl~~~~~( UJd CompanY AB COII$Itallt8
Width and depth or diameter
Periphery ength Area
millimetreS millimetres metre qL1are metre
800 x 750 3100 1755 5440
600 x 650 2500 557 1193
300 x 300 1200 120 144
305 din 958 700 670
250 dia 785 450 353
TOTAL 8000
53
DW154 Specijilarion for Plastics Ductwork
pA XB
Guida ce No es For he ransport Handling and
Storage of uctwork
avoid damage to adjacent duct panels In somc ca es particularly on con acts calling f r repetitive sizes the use of timber jigs and spacers may be justified Where reduced bulk and greater protection are major factor such as consignments for export transporting ductwork in L shape sections may justify the increa ed ite as embly co ts
It is recommended that before a contract is finalised that consideration is given to the subject of site acces material handling and storage as tbcy havgt a strong influence on the cost efficiency of the overall activity of ductwOlk installation
B3 Handling To minilnise th risk of damage duct sections should be clearly identified and deliveries to site should be closely linked to the installation programme so as to avoid accumulation of
B1 Storage and Handling of Ra Material Material should be stored in suitably designed racking out of direct unJight Where possible the e racks should be metal to earth Edges of cut she t may be harp and protective gloves are advised Wearing teel toe-capped boots is recommended Most pIa tic sheet is manufactured with smootb mfaces andor is suppLied with protective coating Care must be taken to prevent accidental lippag of stacked materials Beiuoshy good electrical insulators the movement of stock unless earthed will allow the build up of stati All stock shapes are chemically stable at normal temperature Whil t some raw materials used in their manufacture may themselves pre ent a toxic hazard once incorporated into the lOck bape they no long r constitute such a hazard and no dermatitic bazard are known nor are any
unfiJied ductwork and minimise double handling It is important to recognise that ductwork panels joint and corners arc susceptible to damage and care must be taken wheu band ling such material through a site During handling individual item of duct work may be liable to light cross sectional deformation until thev become an integral pan of a completed ductwork system Whilst this may temporarily detract from its intended appearance thi deformation will not have any detrimental effect on the functionality of the finally a semblecl system Installation of duct work and asociated plant items ill illevitably involve manual handUng The responsibi Iiry of employers and employees to a ses the risk of personal injury during mallual handling operations is et out in the HS E publication L23 Guidance on Manual Handling Regulations 1992
environmental problems expected 84 Site storage
B2 fransport Large capacity vehicles with high-sided open or closed-top bodies are tlle mo t suitable for the transport of dllctwork Careful consideration should be given to the
Adequate floor space IDust be provided within tbe building for the site storage of ductvork Such storage shalt make due allowance for thc stOf(ne of ductwork in stacks such that access ~ egt
between them is of sufficient width to pennil the removal of item without interference to
unloading of transport on sit a not all siJes b n fit from the material handlino- and access facilities that exi [ in a manufacturing workshop such as crane- fork-lifts or loading bay Site handJiog facilities along with
adjoining sta ks Ductvork components should be positioned so a to avoid crushing Ductwork of small panel size may be stored horizontally however care should be exercised to ensure that tack sizes are limited 10 within
ehicular acce s restrictions may itilluence the type and ize of transport to be uWised
engtlls of ductwork should be positioned 0
the tmctural strength of the duct sections to prevent distortion of the lower sections within the stack
as to avoid crushing Lengths Witll projections such as branches and bends i1anges girths damper quadrauL should be loaded so as to
54
DW154 S1tciic(ltioll for Plastics Ductwork
85 Internal cleanliness of new ductwork The site storage of ductwork introduces the important cODsideration of maintaining the internal cleanliness of the ductwork R feren e should be made to HVCA documentshybull DWffM2 Guide to Good Practice - internal
Cleanliness of New Ductwork Installations If the above conditioDs can not be satisfied consideration should be given by tJle designer to amending the specification to include for Po t Installation Cleaning as covered by tJ1C HVCA documentshybull TRJ17 Guide to Good Practic - Cleanliness
of Ventilation Systems
APPE DIXC
Fi e Retardant inishes C1 Improvement in the fire retardancy of plastic
ducts can be achieved to varying degrees and is wholly dependent llPOll the surface coating laminating resin selected and construction specification adopted In some instances smoke emission is coILSidered equaUy with other speci fication requirernen ts of the materials resistance to ignition and bumjng It is therefore important for design rs to establ ish the clients and officers detailed requirements and not rely on a tbird party interpretation of fire resisting or fire retardant Where possible the specification should refer dir etly to compliance with a British or European Standard identifying the specific sections applicable There are various types of resin and mat rcLnforcements that can achieve a Class 1 surface spread of flame ratin o when tested according to BS476 Part 7 (1987) This test puts materials illto Class I - 4 in descending order of perfoDllance according to the rat and extent of flame spread over their surfac under standard beating conditions Materials should also be tested for flre propagarion to BS476 Part 6 (1989) Tbi tesr measures the amount and rate of heat evolved by the material when subjected to standard heating
conditions Test results are given as an index of Perfonnance (i) whicb is based on three sub indices (iJ (i1) (h) The higher the value of the Index of Performance (i) the greater is the material s contribution to fire growth The higher the value of the sub-index 0) rhe greater the ease of ignition aod flame spread The highest product performance classification as defined in Approved Document B of the Building Regulations is Class O This is acLlieved if a material surface of a composite ploduct i~ either a) composed throughout of materials of
limited combustibility or b) a Class I material which has a tlre
propagation index (i) of not more than 12 and sub-index (i l ) of nor more than 6
01 J Class 0 is not a cla$sif1cation identified in any British Standard test
There are resin system reported to be classified to Class O when tested to BS476 Pcl1S 6 and 7 however designers need to ensure that such sysrems can be applied to their proposed design In propriety resinmat system available the fabrication techniques and COITect application are critical to the integrity of the reinforcing and clas ificatiol1 For example in some systems the u e of a non-fire retardant gelcont on a fire retardant substrate would reduce the classification For further information see HVCA publication DW144 Appendix D
55
DW154 SplCijiClIliol1 for Plastics Ductwork
x Guidance otes For nspectmiddoton Servicing a d
Clean-ng Access Openings
D1 GE ERAL This appendix highlight in ummary fOI111
the acce considerations that hould be made by the design r iD terms of inspection servicing and cleaning Having considered the seop and the design of the dUCI work system relative to the guidelines outlined below the designer should clearly indicate which levels of acces should be incorporated into the manufacture of a new duct work system (See Table 14 and Note I b low it
D2 DESIGN CONSIDERATIONS
D21 In ptction and servicing requireshyments are set out in Section 15 of Lhis specification
D22 Cleaning requirements are set out in the HVCA pubUcation TRl7 Guide to Good Practice Clean Lines of Ventilation Systems and the guide tates The precise location ize and
type of access would be dependent on the type of ductwork cleaning inspection and te ting metbods to b adopted Care protection and standards of cleanliness prior LO cOlllmisionin o
are set out in th AV A publication DWITM2 Guide to Good Practice Internal Cleanliness of New Ductwork Installations and th guide state Wh re specific limits of cleanliness are required ductwork sball be cleaned after installation by a spcialist cleaning contractor It will b in the interests of tht desioner botb financially and practically to cunsider employing a specialist c1eauing contractor at tbe
outset of a contract to internally clean newly installed ductwork prior to bandover This approach would reali e the following benefit shyi) Tb actual numb r of cleaning
access panels could be detennined to suit the method of cleaning to be adopted (This may be 1 s than the maximum requiremen listed under Lev 13 of Table 14)
ii) Clear directions could b given to the ductwork contractor as to tJle size and location of cleaning access panels that are required to be fitted during the mauushyfaclunng pro s
iii) The specialist cleaning operation prior to commi ioning vould enable the cleaning contractor to verify the practical acee requirement for the future cleaning operation associated -vitb a regular maintenance programme
iv) A specialist cleaning operation prior to commissioning would allow the designer to omit from the speeilicatiolJ the DWrrM2 requirem nt for factory sealing protection wipe downs and capping-off
v) Specialist Ieall ill 0 to the measurable standard defin d in TR17 will allow an objective definition of cleanline to be achieved
Car ful consideration must be gIven by the designer to the practl aJ problems associated witb the manufacture and fitting of suitably si Led access panel on small cross section duct and on the circular faces of rouod and flat oval ducts in particular
D23 Special con ideration must be given by the de igner to the practical problems associated with gaining personnel access to heavily congested ceiling areas and multi-la red du twork systems This approach would avoid
56
DW154 Spfciication for Plastics Ductwork
the possibility of access panels being D3 ACCESS 0 IN-LINE EQUIPMENT incorporated into a ductwork system at the This appendix unly covers acc il1spection manufacturing stage that were later found in through the ductwork body adjacent to an item practice to be inaccessible for either ervicing of in-line equipment and not openings in the or cleaning activities equipment itself
able 14 Acce requirements for inspection servicing and cleaning
HVCA PUBLICATIO REFE NeE (uidtgt 10 Gund Prartict
Adjace t OW144 Cleanliness orVcnlillltio S~lcr~ fRjJ7
in-line LeyeJ 1 Level 2 Level 3 ite sequipment pcdionSen lcin~ Section d C1eaniJl( SUn(O)lnspc lion Palle ltk~m_n
2011 (minimum OiL Jubje-ct to duct ~zel (ft~ -Panels
Control Da pcrs One (inspection) 203 One 300 mm x 200 mm Both sid Fire Dampers One (sCTjdJl~) 20211 One 300 0101 x 200 mm One side HeatingCooling Coils One (inspedion) 20213 One 300 mm x 200 mm (lIpstream) Both sides Attenuators (rectangular) None required One 300 mm x 200 mm (downstream) Both sides Attenuators (circular) one retluired One 300 mm x 200 mm (downstream) One side Filter Sections One (inspection) 20212 one required Uoth sides Air Turn Vanes None requjred None required Both sides Changes of Direction None required one required One side In-Duct FansDevices One (inspection) 20213 None required Both sides l
1 In the absence of any indication by the designer only Level ) access will be jncorporated into a new ductwork system
2 Tbe panel izes associated with Lev lis I and 3 acee s ar e middottablished by reference to Section 20 of DW144 and Section 2 ofTRll7 respectively
57
DW154 Speclfifatio for Plastics Ductwork
pA XE
B-bliography Included in this Bibliography are technical pUblications which may be of interest (0 ductwork designers fabricators and erectors and to tho e in the heating ventilatlng air conditioning industries generally nquiric should be made of the relevant organisation at the address quoted Since its publication other addresse contained within 0V154 mav have changed and some pubJicalions may have been superseded
HEATING AND VENTILATING CONTRACTORS ASSOCIATION
4 Palace Court London W2 4JG Telephone 020-7229 2488 Fax 020-7727 9268
Orders fo FlY A Publications Old Matlsion House Eamont Bridge Penrith Cumbria CA 10 2BX (Telephone 01768 864771 Fax 01768 86718) Email hvcapoblicationshvwelfarecouk DWn 44 pe ilicatiun for sheet mctal duclwork (Iow- mediulllshy
and high-pressure) 1998) DWIl4 A practical guide to dUGI ork I akage te ting
(revised 2000) DWII54 Specification for plastic~ duct rk DW171 Guide to good Practice for kitchen venlibtion system DW191 Guide to good pracuce glass fibre ductwoJk DwrrMI Acceptance cheme for new products - Redangolar cro
joint classification Guide to good pra tice - Internal cleanliness of new ductwork installations Guide to good practice for the design for the Installation of lire and smoke uampers
J 1Other puhlications
HampV safely guide 5th edition JS2 Tool box talks JS5 Weldlng Safety booklet JSI9 afety facts bo klet Fact sheets 1-24 2nd edition JS2J COSHH manual volume 1 Advice on compliance with the
regulations 1521A CO I-rH manual volume 2 Asses mcnt h ets JS23 Ri k management manual TR3 BrazinltT and bronze welding of copper pipework cUld sheet
(I 976) TR5 Welding of carbon steel pipework (1980)
TR6 Guide to Good Practice for Site Pre sure Testing of Pipework (19 0) Guide to good practice cleanliness of ventilation Ylem
CHARTERED IN TITUTlO OF BUILDING SERVICES E G EERS Delta House 222 Balham High Road London SW12 9BS rTelephone 020-8675 5211 Fax 020-8675 5449) CIBSE Guide Volume A Design Data Volume B In tallatiol1 and quipment Data Volume C Reference Data
CommlssioniJIg Codes These Codes eover the preliminary checkS eUing to work and regulation of vanous catcgories 0 plan The Codes give a guide to design implications Series A Air Distnbution Systems Series B Boiler Plant
ri s C Automatic Conlrol ystems Cr1es R Refrigerating Sy terns
Sene iN Water Distribution Systems
Technkal Memonllda TM 4 Design Notes for the Middle East TM bull Design otes for Ductwork TM 13 Minimi iog lhc Risk of egiounaires Disease
Research Reports RROI95 Ventilation system hygiene - A review of published
infomlatioo on lhe occurrence and ffects of Olltamination Rl~02J95 Air-to-air heal rec v ry RR0395 rnfluen e of HV C on smoke detectors
ATlONAL ENI [ERING SPECIFICATION LfMITED Southgatc hamber 3739 Southgate Street Winchester S023 9EH (Telephone 01962 842058 Fax 01962 R(8982) BUfLDING S RVICES RESEARCH AND [ ORMATION ASSOCIATIO Old Bracknell Lane West Bracknell Berkshire RG 12 4AH (Telephone Brackl1eU (01344) 426511 Fax 01344 487 -7 )
Application Guides AGln4 De tglJing Vana~le Volume middotylans for KOOnl
iir Movement AG1I91 Commissioning of V Sylcms in Buildings 11 6194 Fire Dampers
B) 94 cntiJalion or KitcneTls
AG389 The Commls ionin of Air Systems In Buildmgs AH2192 Commissioning of Bern - A ~ode of Practice TN2417 I Fire Dampec il) Ventilating Ducl
BEATING VENTILATING A AIR CONDITION G MA UFACTURERS ASSOCIATIO (HEVAC) HEVAC Henley Road Medmenham Marlow Buck SU 2ER (Telephone 01491 578674 ox 01491 575024 Emoimiddot infofetacouk)
Publicatjons Air Diffusion Guide Guide to Air Handling Unit Leakage Testing Guide to Good Practice Air Handling Unit Real Room Acoustic ~ st Procedure Specification for the ertiiicatioll ofAir Filters Method of Test for Water Rejection PerfOnTlatce of Louvrcs Subjected 1(1
Simulated Rainfall Test Procedure for Acoustic Loo cs Specification 10 Floor GrilJes - Types Performan e and Method ofTest Specification for the Determination of the Collection Efficiency of SilJ1d
Trap Louvre Domestic Mechwlical Vclltllalion Systems with Heal Recovery Fan Application Guid
~an and Ouctwork Installation Guide Guide to Fan Noise and Vibration
pecification of Requirements for JallJral Smoke and Heal Exhausl Ventilators
pecification for Powered Smoke and Heat Exhaust Ventilators
Specification of Requirements for Smoke Curtains Design Gujue of Smoke Ventilation for Single Storey Lodustrilll Building~
Including those with Mezzanine Floor and IIi Racked Storage Warehou es - Issue 3
Guidance for the Design of Smoke entilation YSlem for Covered and Undergrollnd Car Parks - lssue 1
Application of SOloke Control Equipment and Syst m Guid to Good Practice - Isue J
58
DW154 Sp(C~tiifitiol for Plastics Ductwork
BRITISH STANDARDS INSTIT TION Sales Department 101 P ntooviLle Road London NI 9ND (felephone 020-78 1 78801)
CP 413 1973 Ducts for building ervices
SS 476 Fire tes on building matenals and lruc(ure
Part 4 19 4 Non-combustibility lest or materials
Part 6 I Fire propagation lest for materials
Part 7 1993 Surface spread of tlarnJ tesls for materia
Part 20 1987 Fir resistance of elements of construction
Part 21 1987 Fire r sistlUlce of loadbeanng elements of construction
Part 22 1987 Fhe istallceofllon-loadbearing elemcllts ofconsttuclion Part 23 1987 Contribution of componcnts to the fire resistance 0 a
structure
Part 24t987 Fire resi lance of wl1lilation ductl
SS 5588 nan 919 0 Fire Precautions III thc desIgn and OOSlnJ lion of buildings
S 729 1971 Hot dip galvanized oatiugs (or irOIl aod stcel articles
BS 1449 Steel plate sheet and Irip
Pan 11991 Carbon steel plate heel and strip Part 2 1983 Stainless steel plate sheer and strip
and
B middotENJOI49-2 996 BSEN 10149- 1991)
BSEN 10131 1992
BSEN22063 Sprayed metal coarings 1994 Protection of iron and steel by aluminium and zinc against
atmospheric cOlosion Irotectiotl of iron and ste I against corro ion and oxishydation at elevared temperatures
BS 353 1981 Glossary of lerms relnting to thermal insulation
BS ISO 1479 Self-tapplngscrewsandmetallicdri c crew
B -lSO 7049
1994
B 4800 1989 Painl colour for building purposes B 4848 l0 rolled structural steel sections
Part4 1972 Equal and unequal angles BS 5422 1990 Specification for the use of therm illuating matcriulS
SS 5720 1979 ode of practice for mechanical veutilating and air C 11shy
dirionin bull in building
l3S PR 12814-1 Bend resting for plasric welds
SS PR 12814-2 Tensile testing for plastic welds
SS PR 13067 Appro altesting for plastic welds
BS PR EN I 100-] Vi ual in pection ofplaslic welds
SHEET METAL AND AIR CONDITIONING CONTR-CTORS NATIONAL ASSOCIATION INC (SMACNA) Headquarters 420 I Lafayeue Center Drive Chanlilly Virginia 2051-1209
Mailing Address pa Box 221230 Cbantilly Virginilt120 153-1230
Telephone (703) 803-2980 Fax (703) 803-3732
Accepted IJJdustry Pl3Gtice for Industrial Duct Constnlelion 197 ) i-rchitecmral Sheet kwl Manual ([993)
Comractors Guide lor Modification 10 ooslruerion Colllraets 1993 Ducted Eleclric Heat Guide for ir Handling Ssrerns (1994)
En~rgy ollservatioD Guidelines (1984) Energy Recovery Equipment yslClllS (199l
Fibrou GIns Duct onS1ntClion Standards (1992)
Fire Smoke amp Radiation Damper In tall Guide for HVA Syst ms (1992) Guide t leel Stack 1(95)
HVA Air Duct Leakage Test Manual (19 ) HVA COlllmissioning lvlanual (1994)
H A Duct Construction Standards-Metal amp Flexible (1995) Addendum 01 (Nov 1997)
HVA Duct Systems Inspection Guide (1989)
HVA ySlems-Application (1986) nVAC ByternS-DLlct D ign (1990)
HVi Systems-Testing Adjusting amp Balancing (1993)
indoor Air Quality Manual (1993) tcheu quipment Fabrication Guidelmes (1990)
Managers Guide for elding (1993)
Rectangular Industrial Duct Cons1TUction Standards (19 0) Round Industrial Duct oustmction Standards (1977)
Sei mic Restraint Manual (1991) (wl Appendix E 1993) SMACNA Ma le Index ()fTechnical Publications (1995) Tbennoplnstic Duct CPY ) Construction Manual 1994)
DEPARTME OF THE ENVIRO MENT (Publications Centre) H Stationery Oflice 5 Nine Elms Lane London SWS 5DR
MampEJ 011972 Electrical in tallat1011 in buildings ( ew Editiou)
IampE 0319 Healing hot and cold wat r steam and gas losla1lations for buildings
M amp - No4 1970 Central heating and hot and cold ~ ateT in tallations for
dwelling
M amp ENo100 1971 Mechanical ventilation for building~
ASSOCIATION FOR SPECIALIST FIRE PROTECTlO As ociation House 235 Ash Road AJdershot Hampshire GUl2 4DD
Telephone OJ25221322 Fax 0 J252 333901
lublicalioos Fire Ratcd and moke Outlet Ducrwork An Industry Guide t Design and InSlalla lioll
HEALTH AND SAFETY EXEC TIVE Rose Court 2 Southwark Bridge London SEl 9HS Telephone 020-7717 6000
TWJ THE WELD G TlTUTE Abington Hall Abington Cambridge CB16AL Telepbone 0 J223 89162
Publication DatJ Oil w~ldll1g of lhermopla lics
59
DW154 wciiwlioll for Plastics Ductwork
A -=--DIX
Factors
Specific gravity shy pp = 091 approx UPVC = 14 approx
Some miscellaneous conversion factors
To convert
Length Inches to millimetres Feet to metres
Multiply by
2540 03048
To convert
Millimetres to inches Metres to feet
vIultiply by
003937 3281
Area Square inches to square millimetres 6452 Square millimetres to square inches 000155 Square feet to square metres 00929 Square metres to square feet 10764
Volume Cubic feet to cubic metres Cubic feet to litres Gallons (UK) to litres
002832 2831 4546
Cubic metres to cubic feet Litres to cubic feet Litres to gallons (UK)
35315 00353
022
Mass Ounces to grams Pounds to kiJograms Tons to tonnes
2835 04536
1016
Grams to ounces Kilograms to pounds Tonnes to tons
003527 2205
09842
Volume flow Cubic feet per minute to cubic Cubic metres per second to cubic
metres per second 0000472 feet per minute 2119 Cubic feet per mIDute to litres Litres per second to cubic feet
per second 04719 per minute 2119
Motion Feet per minute to metres per second 000508 Metres per second to feet per minute 197
Pressure Inches water gauge to millibars 2491 Inches wateJ- gauge to pascals (Pa) 2491 I Pa = I ewton per square metre = 10-2 millibars
60
Heating and Ventilating Contractors Association Esca House 34 Palace Court London W2 4JG
Tel 020 7313 4900
e-mail contact Itvcaorguk web site wwwhvcaorguk
Fax 020 7727 9268
DW154 Spediraiml for Plastics Ductwork
Arrangement of bearers and hangers (to be read in conjunction with Table 8 amp 9
wbich list material sizes relative 10 duel izes)
KEY Limits refer to actual duct size - insulation is additional - Typical
attachmentv -Atta hment t strucUlrcI to strucUlrc
I I
I - Flat Bar
I - Drop rod or - utlinc of lllddmg In ulillwn (if
applicable)
Alternative 7 drop rod or rt------------ 1 studdmg q I
I I Rectangular
ii i n 1
Fig 21 Rolled or profiled bearer Limit oncFig 19 Wrap-round hanger Limit 55 DIA
V v Drop rod orAllernaUC 1 1 tudding
drop rod or 1
-- -- 1studding and elded bas 1
I I0 -_
Limit 355 DIA Frg 22 Split clips Limit 1500 DIAFig 20 Flat strap hanger amp split clips
21
DW154 Specification for Plastics Ductwork
6PA deElned in J62 appropriate to the airflow pressure acoustic temperature and corrosion
General
15 ACCESSl SPECTION OPENINGS
151 General These are for inspectionservici ng on 1y
HVCA publication DWIl44 Part 7 - General Section 20 sets out the requirements for access applicable to this specification
152 Cleaningmaintenance Designers shall take specialist advice and then stipulate their requirements for the periodic internal cleaningmaintenance of ductwork and of the consequent need for adequate access for specialist cleaning equipment including the size type and locationfrequency of the actual access openings required
Appendix D sets out guidance notes for the consideration of cleaning access and also makes reference to the HVCA publication TR 17 Guide to Good Practice Cleanliness of Ventilation Systems which covers the su~ject
in greater detail
Note A majority of in tallations in which plastic ductwork is used are considered to have a nigb operational risk potential and provision of access should address this
16 REGULATI G DAMPERS
161 General Balancing dampers and control dampers are elements inserted into an air di tribution system or element of an air distribution sy middottem Balancng dampers permit modification of the air resistance of tbe system and consequently cbanging of the airflow rate Control dampers control tlle airflow rate and may in addition provide low leakage closure of the airflow
The deigner shall specify damper locations taking into consideration that good design practice requires a minimum of five times the diameter or width of the shortest side of uninterrupted flow between plant connections and the damper and select the damper type as
characteristics
1611 Balancing damper To achieve the required distribution of air in the ductwork system at inlets andor outlets for [hi purpose the damper blades are set and Jocked manually in position between fully open and fully closed
1612 Control damper To secure dynamic control of the air now in the ductwork system In thi function the damper will always be power actuated and may require to be modulated between fully open and fully closed and to be capable of taking up any position between these extremes In the fully open position the damper should have a minimum pressure drop In the fully closed position it will not necessarily achieve a complete shut off
162 Types of airflow control dampers Airflow dampers of various types are available for specific purposes as follows
1621 Single - blade dampers Single-blade dampers shall consist of a si ngle pi voted blade cOlllained withjn a casing or section of ductwork The blade shall be adjustable tbmugh a nominal 90 angle by means of a quadrant or similar operating mechanism Where automatic control of the damper is required the spindle shall be extended to enable a powered actllator to be mounted
Single-blade dampers shall have a maximum duct width of 400 nUll and a maximum duct height of 400 mm for rectangular ducts and for circular ducts a maximum diameter of 400 mm
1622 Multi-blade dampers Multi-blade dampers shall consist of a number of pivoted blades contained within a casing The blades shall be
22
DW154 Sedicalirm for Plastics Ductwork
adju table through a nominal 90deg angle simultaneously by intershyconnected linkage or gears connected to a quadrant or similar operating mecbanism Where automatic control of a damper is required a spindle shall be extended to enable a powered achlator to be mounted
There is no restriction on the size of duct in which multi-blade dampers or damper assemblie may be u ed Where dampers are required for blade lengths in excess of 750 mm the blades should be suitably reinforced or supponed 0
individual damper blade should exceed 200 mm in width
1623 Iris dampers Lris dampers shall consist of a nUlllber of radialty interconnected blades which open or close within a casing with duct COlll1cctions The blade shall be simultaneously adjusted by a quadrant or similar operating mechanism
Iris dampers shall be installed as specified by the manufacturers operating and installation instructions where the product is unidirectional with regard to airflow
lris dampers are available for circular ducts only in diameters up to 250 mm (it should be noted that the damper casin i appro)(imately twice the diameter of the duct)
1624 Backdraught dampers Air pressure operated uni-directional rectangular (single or multi-blade) with adapters if fitted to circular ducts
1625 Slide and blast gate dampers A damper [lsed as a shut off facility with an externaJ Lide bousing allowing the blade configuration to be fuJly inserted to fully extended for maxiDlUlll air flow
163 Construction
1631 Materials All products shall be protected against cOHosion as necessary and supplied in a fully finished condition as specified by the designer
1632 Dampers used in low and medium pressure systems The following recommendations apply to dampers forming an integral part of ducrwork with pressure classifications A and B air leakage limits
The dampers shaH be constructed to minimise distortion and prevent jammin in operation Th blade shall be sufficiently rigid to minimise movement when in the locked pOSitiOLl
The blades shall be securely fixed to the operating mechanism All balancing dampers shall have a locking device located on the outsid of the case and shall giv clear indication of the actlwl blad position All penetrations of the duct shall be fitted with suitable seals where necessary
1633 Dampers used in high pressure systems Regulatino- dampers used in duc[work sy tems to pressure cJassification C shall meet tbe construction requireshyments specified in 1631 and 1632 with operating mechanisms out of the air-stream
1634 Proprietary types of damper The use of any specific type of proprietary damper shall be confirmed by the designer In all cases proprietary dampers shall meet the relevant requirements of thi specification
1635 Damper casings Duct damper casings hall be constructed to meet th mllllmum
23
DW154 SpeciJimlioll for Plastics Ductwork
leakage Iim its sp cified for th c1uctwork ystem to which tbey are installed
In order to apply the square metre leakage calculatio as detailed in DW143 A Practical Guide to Ductwork Leakage Testing the reference casing area ball be taken as the perimeter ize of lh damper IDultipli d by the equi alent length of Imetr eg an 800 mm x 400 mm duct damper hall have a surface area for casillg leakag p donnan calculated as follow (2 x 08) + (2 x 04 x I
=24m2 casing area
Other pelforlllance ancl rating test methods for damp f and valves are specified in ISO 5129 and BSIE 1751 and are referenced belm a) Leakage past a closed damper
alve BSIE 1751 b) low ratepre sure requirement
characteri t cs BSIE 1751 c) Operational torque le ring
BSEN 1751 cl) Thermal transfer testing
BSIEN 17 I e) Reg nerated sound power levels
ISO 5129
164 Installation Dampers shall be imaalled in accordance will) any re Ievant ISO EN or British Standard 10 aJ bUT lcling regulation and national code of practice as well as the manufacturers recommendations
17 FIRE DAMPERS AND INT MESCENT SLEEVES
171 General Damper or sleeves arc requiTed on duct y~telll where the designer has -tjpulated the
duct wiU penetrate a fire compartment in the majority of application tbermopla ti ductwork is ugtecl where contamlDated corro ive or otherwise exceptional fumes are concerned it is preferable to use tire damp r which are externalJy mounted ie of the intmnescent operated crush typ
24
72 Fit-e rating The damper assembly should have a fUT
resi tance ratin o equal to that of the fir ban-jer it penetrate and ball be fire tested and rated to the timetemperature curv of B 476 Part 20 and 22
173 Intumescent sleeve At the time of writing this specification qualified test results were available for rectangular dampers and circular dampers up to 55 mm diamet r Manufacture have indicated that they are able t provide speci fications for other size and diameters This infonnation should be confirmed b th de igner Various type are available includino
tho e incorporating ruechanical closing plate and those operated anI by expanded iJllUme c nt media
In all ca es fire damp rs and intnmeBcen leeves shall be supplied and in taUed in
accordance with the manufacturer iJlStructioos and COSHH a essm nt
174 Other types Fire dampers of mious types are availabl for specific purpose~ ee HVCA publication DW144 The de igner should )lot (hat materials for con lt1Jction bould be uitablc for the par1icular application
ALL C SES FIRE DAMPERS AND fNT MESCENT SL _VES SHALL HE S PPLTED AND INSTALLED IN A ORDA CE WITH Tf--IE MANUshyPACTURERS STRUCTTONS AND COSHH ASSESSMENT
18 FLEXIBLEEXPANSION dOINT CONNECTIONS
181 General ploperties Tbe material u ed for flexibleexpan ion iojnt~
mu t meet the design r requirements for temperature air pressllrelfe resistance applicable to pl astic duct sy tem vibration and noi e br akout when incorporated into a jointconnection and shall comply ith lh standard of air-tigbtne specifi cl for the duct work sy tem of which it fOlms part (See Figs 23 24 5 26 27 amp 28 for typical con truclion clelai Is
DW154 SJecilimtol for Plastics Ductwork
Expansion joints
Fig23 Moulded bellows type (rectangular and circular)
Fig24
~F aiblc sleeve
__ liding sleeve
~~~~
Sleeve type (circufar)
Fig 25
AIRFLO
COnlinuou~
weld~
Flexible Iceve
PV A HOWN pp SE BACKING FLATS AS FIG 2
Sliding lee c Co1linuou
weld
Flanged sleeve (rectangular and circular)
25
DW154 Specificatiol for Plastics Ductwork
Flexible con ections
Fig 26 Flexible sleeve with clips (UPVC and PP)
--__ Flexible I eve
I
I
I CODn clioD to plant ~
Band clip
Fig27 Welded flexible sleeve (UPVC only)
Plastic)sed PVC slceve ~-- onll11uo1sly welded
onrreclion to planl ~
Fig28 Flanged flexible connection (UPVC and P )
t sp dally moulded flexible flanged connCClitlll
boil
C)nneclion to plant ~
26
DW154 Specificotiol for Plastics Ductwork
182 LOClt1tion Flexible joint are typicltllly lIsed at building expansion joint and fan inletsoutlets Any others required should be indicated on the de ign drawings Care should be taken to maintain alignment across jointsconnections
183 Length Flexible Jomts shall be kept as short as pra middottieable above a minimum eft ctive length of SO mm In no ca e shall a flexible joint exceed 250 mm in lengtb
184 Connections to rectang a ducts With flanged rectangular connections Ule tlexible material shall be held in pLace with flat pIa tic strip of not less U1an 6 mm thick ltlttached to the flanges using uitabJe fixings The more heavy weight type of fleAible mateLial may also be obtained formed into a channel ection with corners fitted to give a neat air tight j int For pigot connections the Be ible material shall b held in place with flat pIa tic trips n t less than 6 mm thick
t 85 Connections to circular ducts With tlanged circular connections the flexibl material shall be held in place with flat plastic backing strips or proprietary clip bands with screw or toggle fast ners
186 Welded flexible connections (Rectangular and Circular) Where the parent and llexibl material are from imilar ba ed products they can be joined to the duct u ing the welding method described in Section 823
19 PROTECT VE FINISHES
191 nles otherwise stated all ductwork shall be mallllfactured in mat fial as pecified in tbis specification Any special coatingpaint fmishes to be provid d by the duct work contractor sball be advisd by th de igner
20 CONNECTIONS TO BUILDING OPENINGS
201 Fanning and finishing building op nings are not the repoJlsibjlity of the duftw( rk contractor and the note that follow are for guidance purpo e only
2011 Openings in brick block or concrete walls shall have inset frames to provide a suitable means of fixing grille louver masking flanges or the tlanged ends of ductwork The illset frames shall be conslnlcted to maintain the structural int grity of the wlll and where applicable cavities shall be suitably lined
2012 Openin s in dry linino partItIons shall have inset frames a 2011
2013 Openjngs in cladding walls and roofs shall have flaoged leevesframes to provide a suitable means of fixing a 2011
2014 Horizontal and vertical opening xposed to oLltside atmo phere hall
be provided with a suitable weathering fini h at the external face especially where profiled cladding is used
2015 Timber framed op nings are not permitted In fj re compart ment barriers
202 Ductwork connections to building openings hall have a flange of suitable profile to permit practical fixing to the openillg frame In selecting the profile consideration shall be given to Tabl~s 2 and 10 in this specitication relating to duct ize and rating Gasket strip or sealant shall be ltlpplied between the tJaoge and building op ning frame
21 DISCHARGEEXHAUST TERMINAL
21 Tbese shall be vertical open ended and designed to meet and comply with current r gularions on contaminated flue The designer hall ensure that the de ign and perf rmance i suitable for its intended purpose Examples of some typical terminal designs are SbOiD in Figbull 102 10 bull 104 amp 105
27
DW154 SpedjimioTl for Plastics Ductwork
22 THERMAL INSULATION
221 The provision and application of thermal insulation to ductwork is not the responsibility of the ductwork contractor
222 Where ductwork is required to be preshyinsulated the specification should be agreed with tbe designer
223 Where the temperature of the air within the duct promotes condensation on the exterior surface of the duct and cause moisture penetration througb the thermal insulation vapour scaling may be required and in this case the most important requirement is to limit penetration of the seal
The extent of any vapour sealing of ductwork thermal insulation and the support method to be u ed must be clearly pecitled in advance by the designer
224 For detailed information on the thermal insulation of ductwork reference should be made to BS 5422 1990 which covers the specification for thermal insulation materials on pipes ductwork and equipment (in the temperature range -40degC to +700degC) and BS 5970 1992 which is a Code of Practic for Thermal Insulation of Pipework and Equipment (in the temperature range -lOOdegC to +870degC)
23 FIRE RETARDANT FINISHES ON PLAST C DUCTWORK
231 The designer should note tbat ductwork constructed to DW154 has no teted fire rating or information see Appendix C
24 REINFORCEMENT OF DUCTS WITH GRP LAMINATE
241 General Where ductwork is required in larg T izes than are covered by Tables 2 4 6 amp 7 or with the increased strength sometimes necessary for industrial use external reinforcement is normally pwvided by applicatioD of glass fibreresin laminate
GRP systems will bond satisfactorily with standard UPVC sheet but for pp it is
nece sary to use a specially prepared sheet with a glass fabric backing incorporated dOling manufactllfe
The detailed techniques of fabrication using GRP are outside the scope of this speci lcation but the following notes are offered for guidance of ductwork fabricators
242 Materials
2421 Quality The laminate is made up of polyester resin complying with BS 3532 and glass fibre complying with BS 3496 or BS 3749 The nominal ratio of resin to glass fibre should be 7030 by weight
2422 Minimum properties The laminate shall comply with the followiog mini mum pbysical properties
Tensile strength - 70 MNm Tensile modulus - 7 Gl m Flexural strength - 140 M Im Bond strength (hetween laminate and substrate Not less than 7MNm Bmcol hardnes Not le s than manufacturers specification
The GRP reinforcement educe the expansion of the parent material but the resultant stre ses arc well within rhe strength of the bond However the Iinear thermal expansion curve shown in Figs 34 amp 35 will serve as a guide
Surface resistivity electrkal propcltles and acoustical propertie are similar to the relevanl unreinforced materials The fire retarding properties of GRP may be improved by the use of specialisl laminating resin
2423 Forms available GRP Laminate should be built up from the separate materials ie resin aod glass fibre in the form of chopped
I strand mat or spray ravings
28
DW154 Spcification for Plastics Ductwork
2424 Workshop conditions Polyester resuls are sensItIve to lmperature and the workshop hould b maintained at a temperature of herween 20deg and 25degC HiOh relative humidities and damp onditions should be avoided A good rate of air change must be pro icled pJeferably by m chanical ventilation
2425 Storage of materials Resin and urin o agents shouJd be stored in dark cool condirions away from the working area and in confonnit with statutor requireshyments for tJle middottorage of flarmnable liquid Because of Ule Limited torage lif of the unmixed resin and curing a eot mal lials ~hould be ch eked before use to enLlfe that they are within the manufacturer pe ified sh If life (usually ix month from the dm of manufacrure)
Glass fi re should be stored separately und r clean dry conditions
243 Surface preparafon
2431 UPVC To achieve the specified bond strengtll the urface to which the GRP is applied mut first be thoroughly cleaned and then etched either by mechanical means or by the use of a suitable solvent
2432 pp with glass fabric backing To achieve the specified bond middottrength the fabric backing must be thoroughly impregnated Witll resin
244 Mixing the materials for use The re in 1 a three part mix compri lng base I sin hardener and accelerator The manufactur rs pecj[ied proportions are critical and th llUxmg sequenc pecified must be meticulously foUowed
The resin has a very limited life after mixing and before u e It is dependent on the characteri tics and bulk of th resin the alllount of hardener the degree and method of acceleration and the workshop onditions
245 Methods of application
2451 General The mixed resin may be applied by hand or b pray c1epoition The operation must b completed within the gel time of th y tern and tbe laminat fully cOI1olidated to achi v the phy ieal properties pecified
2452 Hand lay-up The duct surface i coated by hand with resin Llsing a brush and a mar of gla fibp orked in until full consolidation achieved Th proc is repeated untiJ th requird thicknes i obtained
2453 Spray depo Won The duct surface is coated WiUl re in by spray gun with the chopped glass roving added through a separate nozzle The full thickne i obtain d in layer with con olidation of each layer by hand roller
246 Construction
2461 General M ini mum COllst ructional requireshyments are pe itied ill Tabl 10 for rectangular and Table 1J for circular dUClS
2462 Joints and stiffeners Fig 29 30 31 32 amp 33 hoI TOSS
joint and tiffener for reinforced UPVC and PBPP duct
247 Worki g practices The fabrication of ductwork pecifiecl ill thi document i not affected by the addition of GRP
29
DW154 SfJcdJicatiOt for Plastics Ductwork
Table 10 Minimum constructional requirements shy
Longer Side Minimum Sheet Thicknes and
GRP Reinforcement
UPVC FBIPP 1 2 3
mm mm mm Up to 1000 3 plus 3 plus
06 kgm2 06 kgOIl GRP GRP
1001 to 2250 45 plus 3 plus 06 kgm 12 kgm
GRP GRP
2251 to 3000 45 plus 6 plus 12 kgm 12 kgm
GRP GRP
Cross Joints
UPVCFBPP 4
mm socket amp spigot
as Fig 30 or flanged as Fig 29
75 x 9 flange welded on both sides as Fig 29
75 x 9 tlange welded on both sides as Fig 29
rectangular GRP reinforced ducts
SlifTeners Maximum Spacing Between
JointsSljffeners UPVCIFBIPP UPVCFBPP
5 6 mm mm
75 x 9 flat 800 as Fig 31 or
50 x 50 x 5 plastic or MS inverted angle as Fig 32
or tormer as Fig 33
75 x 9 flat 600 as Fig 31 or
50 x 50 x 5 plastic or MS inverted angle as Fig 32
or former as Fig 33
75 x 9 flat 600+shyas Fig 31 or 50 x 50 x 5 plastic
or MS inverted angle as Fig 32
or former as Fig 33
Note 1 On rectangular duct up to 400 mm longer side no stiffeners are required 2 Applies to Tables 10 amp I I For COlJstructional operating temperature limits refer to Part 2 clause 5A 3 Tables 10 amp II apply to all pres ure classes up lo ]500 Pa
Table 11
Diameter
1 III
lJp to 1000
1001 to 1750
1751 to 2500
Minimum Sheet Thickness and
GRP Reinforcement
UPVC FBPP 2 3
mm mm 3 plus 3 plus
06 kgm 06 kgm GRP GRP
45 plus 3 plus 06 kgm2 18 kgm
GRP GRP
6 plus 6 plus 12 kglm2 18 kgm1
GRP GRP
Cross Joints
UPVCFBPP 4 III
socket amp spigot as Fig 30 or flaoged as Fig 29
75 x 9 flange welded on both sides as Fig 29
75 x 9 flange welded 00
both sides as Fi 29
inforced ducts
Maximum Spacing Between
JointsStiffeners UPVCIFBPP
6 mm 2400
800
600
Stiffencrs
UPVCFBPP 5
mm 50 x 9 flat as Fig 31
75 x 9 flat as Fig 31 or former as Fig 33 75 x 9 tlat as Fig 31 or t()rmer as Fi 33
ote On extruded tube tip to 600mm diameter no stiffenergt are required
30
DW154 Specificatioll for Plastics Ductwork
G - Cross joints and tiffeners
Fig 29 Flange Joint Fig32 Stiffener shy inverted angle
M artiPfCuQkbdd erttpObri) Wl111 RP tlddtlt
_- GRPloliu] lh~
Fig 30 Socket and spigot joint Fig33 Stiffener shy use of former
Fig 31 Stiffener Flat
I Pv FlPP ~ ~lmJaDUA1) d
OMrlQ rrnall 1( tQlS
25 STANDARD COMPONENT DRAWINGS AND ABBREVIATIONS
251 The illustrations in this section not only highlight where applicable geometric limjtations for the de ign and manufacture or ductwork components but also recommend
standard drawing representation terminology and abbreviations for both duetwork components and some of the more commonly used ancillaryplant items
252 Designers and surveyors should note that bills of quantities should provide a full description
3)
---
v
DW154 Spcc(fim(ml for Plastics Ductwork
Fig 34 Linear Thermal Expansion
u c 0 N ro 0)
b 0)
S
sect0
5 oS cl) 0)
~
on ~ ltl
c U
-30 -20 -10 0 10 20 30 40 50 60 70 80 90 TEMPRATURE C
~ V
-
~~c_ ~
~V
V ~
-7 ~
-- ~V ----
v
-6
+14
+12
+10
+8
+6
+4
+2
0
-2
--4
ig 35 Typical Design Stress tor UPVC and P
7
6
r shy 5E
-c E----0 4t) VJ 0)
ci5 0Jl 3
~
0)
Cl
2
1
o
UPVC
1
000
1
1
pp
- r-- shy r----- shy - t--shy I
__0
-30 -20 -10 0 10 20 30 40 50 60 70 80 90 TEMPERATURE C C
Note Figso 14 amp 35 shaded area refers to GRP reinforced duct
32
DW154 Speciicfltirm for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - REC ~NGULAR
Splilt~r Posilion W-mm pliucr
A B c 40]--QOO 1 W - -
601-1000 1 W4 Wf2 -
1001-1800 3 WI W3 W2
FIG DRAWING DETAfiS
tU]36 ATI Straight Duct with socket and spigol joint
rn [037 Straight Duct with flanged joints
[I []38 Straight Duct with flanged joints
rkJ Short Radius Bend
39 Applies to any augl and for duct up to 400 n11n wide
Minimum (I1m31 radills = 100 mm
Medium Radius Bend (a illustrated)
[kJ Applies to any angle
40 Long Radiu Bend Similar but radius = W
Throlll radius = W2 Applies to any angle
- Short Radius Bend with plitlers
I -shy -shy u co - t lt Li--_ 41 t 0 ~ I I I
~ I
L 1W
Minimum waal radius = 100 mm Splitters not required in bend angle less than 45deg
42 QJ1 Square Bend with turning vanes ij
3
DW154 SP(L~ficatioll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - RECTANGULAR
FIG DRAWl G DETADS
43
~
I v
L L Radius Tee with internal deflectors
44
~ Radiussed Twin Bend
45
Imiddot
er Swept Branch
46 U-
Sqoare Tee with Turning Vanes
47
~ f
Breeches Piece
48 0 y l Piece
34
DW154 Specificatioll for Plastics Ductwork
STANDARD COMPONENT RAWINGS - ECTANGULAR
55
54
51
50
53
52
49
FIG
~MX
RAWlNG
DmiddotMAX
EfjMAX
Minimum throat rndius = 100 mm
Rectangular shy Round Transformatioll
Eccentric Taper 225deg max in either plane Spliller are required for angles greater than 225deg and hould bi eet the angle between any side and duct centreline
DETATLS
Angled Offset
OUset Taper Splitters are required for angle greater than 22 0
and shoold bi eet the angl between any side and dUCI centrelinc
Mitred Offset
Concentrk Taper 2250 max in ither plane SpUtters are required for angle greater than 225deg and should bisect the angle between any side and duel c ntreline
Radiussed Offset
35
DW154 Splcilcuthm for Plastics Ductwork
STANDARD COMPONENT DRAWINGS ~ RECTANGU AR
Branch ducl DimCllsions widlh (W) (A)
urnl mm up lO 200 75
300 100 400 125 600 150
Ocr 600 200
FIG DRAWlNG DETAILS
56 poundplusmni~~ Rectan~lar - Flat Oval Transformation
57 [ Square Branch
58 er Angled Branch
Branch dUCI Dimensions wfdth (W) (A)
[- mm mm59 3shy Shoe Branch Up (0 200 75
--shy AIshy + 300 100
400 125
450 MAX 600 150
Over 600 200
Branch duct DimensIOn
rP X width (W) A)
60 - 1--shy _
~ mm mm
Bell Mouth Branch pto 200 75 300 100 t 400 125
600 150 Over 600 200
0=0 61 -
~ Bell Mouth
- shy T 4-5deg M x
--I 1-shy
TJ
62 X I ] I
Tele-scopic Joint I Illustrated with flangeL
X63
SBD Single Bladed Damper
36
---
DW154 Spedicatioll for Plastics Ductwork
STANDARD OMPONENT DRAWINGS - RECTANGULAR
DRAWING DETAILSFIG
64 on-Return DamperNRD shyshy
shyXbull
Multi-Leaf Damper Can be piggoted or flanged oppo cd or parallel blade
Alternative controls areshy
q p [gtshy
J HD65 Hand
~MD otori ed
PO Pneumalic
L-lt
l 13G 66 Blast Gate DamperX X
FireSmoke DampersSleeves
211r Ratinggtshy----
L_-
---
----
r----
Ir-- shy
IL- _-l
2hr
With i tallation frame
67 41 r Rating
4hr
Smoke damper SD
Intumc cent Sleeve L-d
37
DW154 Specijicutiolt for Plastics Ductwork
FIG
68
69
70
71
STANDARD COMPONET DRAWINGS shy REC ANGULAR
DRAVING DETAILS
gtshy Access Openings
AP 6 Access Panel - Rerno able
w [ ~ Access Door - Hinged
I ~le Inspection Cover
le -I reg -lt
~X X Flexible Connection
~ Drop Cheeked Radiussed Twin Bend
U Drop Cheek Bend
I
72 Air Flow SymbolX
38
DW154 Specifim[ioll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - ECTANGULAR
FIG DRAWING DETAILS
73
74
75
76
77
Q
Q
rp---t
~
V- I Ir---I
JL --11
THE ABOVE DETAILS TYPICAL PLENUM
Air Terminal Plenums
Plenum with side connection
Plenum with top connection
Cover plate with connection
Special plenum with connection
elescopic conn ction in direction of air flow
39
DW154 SpecijicotiOll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG
78
79
80
81
DRAWING
-23~---pound3-(MALE) (FEMAJE)
-t=j--_j(--d-shy
--L
~ THROAT RADI S= D AS T NDARD
e ~
THROAT Rjf)lU = D A MU)
DETAILS
Straight Duct With male and female connectors
Straight Duct With flange joint and slip joint
Bend MouldedIFormed Applies to any angle ego 30deg45deg60deg90deg Medium radius bend as illustrated Long radius similar but throat radius 0
Segmented Bend 90deg four section minjmum as illustrated
Other Angles 60deg = 3 sections 45deg = 3 sections 30deg = 2 sections
I
i
40 shy
DW154 Speciicafinll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG DRAWING DETAlLS
82 Segmented Twin Bend Radius = D2 max
May also be fabricated from tube
83 Equal Tee MouldedIFormed
84 -~ 1in Bend MouldedIFormed
85 Taper Concentric 1 0 as iUu trated Eccentric 30deg iJJcLuded angle
86 Short Taper
41
DW154 SpcUicatol1 for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG DRAWING DETAILS
87 30 max Offset
Angle Branch
Bran h dUCI Dimcnsions dia (D) lA)
Shoe Branch mm mm 88 Cl
Off rectanguJur Up 10 200 75 lOO 10 400 125
- 00 150 Over 600 200
Bl1IllCh duct DimenlOns din (D) (A
~-$a-Conical Branch mm mm
89 Also acceptable with Up 10 200 r
full conical surface 300 10
400 125
END VrE -shy 600 150 Over 600 200
90
m 75
100 12 150 200
mm Up to 200
_ 300 400
600 Over 600
iUtred Branch
Shoe Branch
J-L----U ~ Bell oulh Branch
ENDV1EW
93
92
91
42
DW154 Specificatiol for Plastics Ductwork
STANDARD OMPONENT DRAWINGS - CIRCULAR
FIG
94
DRAW G
I
~ 30deg 090deg
Breeches Piece
DETAILS
95 amp-----~ Blank End
~-----p Multi-Leaf Damper Can be piggolcd or fianged opposed or parallel blade
Alternative controls areshyri=-+- L-T~
I
---
LT~
I r- -
-+1
J HO Hand96
bMD Molori cd
PD Pneumatic
tl-shy bull
Single Bladed Damper 97 ~ saD
on-Return Damper Vertical application only 98 m~D
43
DW154 Sf1tcificatioll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG
99
100
101
102
DRAWING
$ I-
2hr
1 4hr
SD
~v I I
CO TINENTAL COWL
DETAILS
Iris Damper
Fi reS moke Dam persSleeves
2hr Ratillg
With installation frame
4br Rating
Smoke damper
Intumescent Sleeve
Access Openings
Access panel - removable
Access door shy hinged
fnspection cover
Discharge Continental Cowl
44
DW154 Sp(Cii(ltJll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
DRAWINGltIC DETAns
-
I
I
~
I I I High Velocity Discharge Terminal 103 I
I
I I
J I I 1 ~--
Offset Stack Discbarge Terminal 104 1
~ I e --(-
I
N
I
I
I~
I I Vertical Oischarge with Weather Cowl 105 I
--1--1 I
I
GAPI I
RTl AL DISC) lARGE WITH W ATIIER COWL
45
DW154 SpecUicatoll for Plastics Ductwork
STANDARD COMPONE T DRAWINGS - PLA TEQUIPMENTIMISCELLANEOU
FIG DRAWING DETAILS
106 ~~~ Rectangular Attenuator
107 ~- Circular Attenuator
108
~ Beod Attenuator
109 J ~(f) Heating Coil
110 J ftte Cooling Coil
III Jc[ Electric Heating Coil
112 X F
Humidifier
113 [H XX Axial Fan
114 ~fB1famp Noo-standard Ductwork Cross hntchillg (of any separate type) indicates by reference to a key any non DVil54 ductwork system
115 2llIIIIJIIIIIll Flexible Ductwork
46
DW154 SJeCUicll(iol1 for Plastics Ductwork
TABLE 12 - STANDARD ABBREVIAT ONS
ABBREVIATION FLL
AD Acces Door
AFF Axial Flow Fan
AHU Air Handling nit
All Aluminium
AP Acess Panel
AT Attenuator
AV Air enninal Unit
BE 81ank nd
BQ Blast ate Damper
CC Cooling Coil
CF Centrifugal Fan
CTA Cross alk Attenuator
CVU Constant Volume Unit
DP Drain Point
EEC Electric Heating Coil
El Expansion Joint
FAl Fresh Air Inlet
FA From Above
FB From Belo
fBPP Fabric Backed Polypropyl-ne Sheet
Flexle Flexible Connection
lexfD Flexible Du t
C False Ceiling CO an oil Unit
fD Fire Damper
FFL Finished Floor Level
FJ Flanged Joint
FOAM Rigid Polyurethane Self xtinguishing Foam
FOB Flat on Bottom
FOT Flat on Top
GAM Galvanised after ManufacttrJc
GRP Glass Reinforced Plastic
GSS Galvanised Sheet Steel
HC Heating oil
HD and controlled Damper
HH Hand Hole
HL High Level
HVD High Velocity Discharge
IC Inspection Cover
ID lri Damper
IFS Intumescent Fircleevc
47
DW154 Specification for Plastics Ductwork
TABLE 12 - STANDAR ABBREVIATION CONTINUED
ABBREVIATION
IU
L
tv1D
MS
NRD NTS
OBO
OE
PHD
PD
PP
PP
PRD
PVC
RFC
RSC
R
SBO
SO
S1 TST
SSL
TA
TB
TO TJ
TP
TV
TV
OS
UPVC
S
V
VAV
50 RSA
FULL
Induction Unit
Low Level
Motor controlled Damper
Mjld Steel
on Return Damper
at to cale
Opposed Blade Damper
Open End
Parallel Blade Damper
Pneumatic controlled Damper
Polypropylene
Self xtinguishing Polypropylene
Pressure Relief Damper
Polyvinyl Chloride
Rolled Form Chamlel
Rolled Steel Channel
R fUnit
Singl Blade Damper
Smoke Damper
Slip Joint
Stainl t el
tructural Slab Level
To Ab vc
To Blow
Top Down (In Direction of Flow)
Telescopic Joint
Test Point
TU111iog Vane
Top Up (In Direction of Flo )
Voles Otherwise Stated
Unpl3sticisecl Polyvinyl Chloride
Underside
Ultra Violet Light
Variable Air Volume
Rolled Steel Angle (Vith Size)
48
DW154 SJeriiflllioll for Plastics Ductwork
A2 DUCT PRESSUREAPPE DXA Ductwork con truct d to DWIl54 will bebullbullbullbullbullbullbullbullbullbullbullbullbullbull
Air Leakage From Ductwork To be read in conjunction with DW143 A practical guide to Ductwork Leakage Testing
CAUTION As highlighted ill both this docul1lenr and DW14 I lot ellough emphasis can be placed 01 the fact that except for high pressure class C the much more stringent ductwork constructional standard brolght about b the general acceptance of DW154 have irtlally negated the requirement for leakage-testing It is essential lO realise lhat except where it is mandatory this doclllllelll is nOl an endors ~lIlent of the rourine testing of ducts bllt purely a guide to outline the procedures for cononnity with the air leakage limits ill Table l Where the specified methods of assembly and
A3sealing of dlcls are u ed a vi ual inspection wil ordinarily sl~fll e for ver(iatioll of a well engineered and a ceptahfy airtight COl1strucrioll WHERE NOT MANDATORY DUCT LEAKAGE TESTING IS GENERALLY AN UNJUSTIFIED AND SUBSTANTIAL EXPENSE
A1 INTRODUCTION L akage from ducted air distribution systems is an Lmportant consideration in the design and operation of ventilatjon and air conditioning middotystems A ductviork t)ystem tbat ba limited air leakag within defiucd limits wiH cnsUft
that tile design characteristics of the sytem can be maintained It wilJ also ensure that energy and operatLonal cosb are maintained at optimum levels DucLwork constlucted and Ulstalled in accordance with DW154 should minimise a level of air leakage that it) appropriate to tll operating static air pre sur in tile system
A4However it is recouuised that tbe environment in wtJich middotystems are installed is not always conducive to achieving a predictable level of quality in term of system ajr leakage and it is therefore accepted that designer may sometimes require tlle ystem to be tested in part or in total It should be ecogni ed that the testing of duct systems add a ignificant cost to the installation and incur some extra tjm within the programme (Se 47 and 64 re mandatory te-sting)
manufactured to a structural standard that is compatible with the system operating pressure There are three classes of duct con truction to eorre pond with the three pre ure clas meations Class A Lo pressure ducts suita le for a maximum positive operating pressure of 500 Pascal and a maximum negative pressure of -500 Pascals Class B IVledium pressure ductmiddot suitable for a rnaxilnuJJl positive operafjn o pressure of 1000 Pascals and a maxllnum negative pre sure of -750 Pa cal Class C High pre sure ducts suitable for a maximum po ilive operating pressur of 2000 Pa cals and a maximum negativ pres ur of -750 Paltcals
LEAKAGE FROM DUCTWORK Leakao-e front pia tic air ducts occur at the joint~ and is therefore proportional to the total surface area orthe du twork in th system Tb level of leakage i imilarly related to tIle air pres ure in th du t system and whilst there LS n precis formula for calculating the level of air los it i generally accepted that leakage will increase in proportjon to pressure to rbe pOvver of 065 The effect of air leakage from high pressure velocit ductwork is critical tn terms of system perfomlan dege energy consumption and the risk of high frequency noise as ociated with leakage These problems are le critical with medium pressure 10 ity systems but should be con idered Low pres mevelocity ducts present the lowe~t
ri k in tenn of tbe effect of leakage on the operation of the s stern
SYSTEM LEAKAGE LOSS As there i no di ct relatLonship between th volume of air conv yed and the surface area f the ductwork sy tern required to match the building configuratmn it is difficult to express air leakage a a percentage of total air volume Similarly the operating pressure will vary throughollt lh 3 system and a leakage is related to pre me the calculations ar comple However it is generally ac epted tbat in typical good quaJjty systems the leakage from
49
DW154 Specificatioll for Plastics Ductwork
each class of duct llnd r operating condition will be io the region of CIa S A low pressure 6 Clas B medium pres un 3 Clas C high pressure 2
A5 SPECIFYING AIR LEAKAGE TESTING Re peeting both the co -t and programme implications a sociated with te ling du 1 for leakage the designer may for example indicate that a particular system is te ted as follow
a) High pressure ducts - all tested b) Medium pr ssure duets - 10 of the
ductwork shall be s eet d at random and tested
c) Low pre sure - unte ed In any case where a random te t i elected for medium pre sure ductmiddot the followin c1au~e is suggested for inclusion by the de ign r
The designer hall elect at random a maxirnwlI of 10 of the dUCl system to bt tested for air leakage The duct hall be tested af the pressure recommended in Table J3 for the assifi atiol for the ectiol1 of the ductwork that is to be tested The tests shall be carried Ollt as the work proceeds and prior to the application of thermal insulation In the event of test failure of the randomlY selected section the designer shall have The right to select two La1her e tiolls at random for resting Where succes ive failures are identified there shall be a Tight to require rhl COl11raCWr 10 apply remedial attention to the complete ductwork system Th contractor shall provide documented eviden e of the calculalions used to arrive (1
the allowable 10 I for the section to be tested and the client or his agent shall willess and sign the results of the test
able 13 Air leakage rates
Maximum leakage of duct work Static
prcssUft Low-pressure edium-prc-sure I Iigh-prebull me diJfercntial Class A Class B Class C
1 2 J 4 Pa Litres per second per quare metre of surface area 100 054 018 ZOO 084 028 300 110 037 400 132 044 500 153 051 600 058 019 700 064 021 800 069 023 900 075 025
1000 080 027 1100 1200 1300 1400 1500
029 030 032 033 035
1600 1700 1800 1900 2000
036 038 039 040 042
Note Recommend d mean test presures are highlighted iD bold type with the actual selection being left to tll test operator
50
DW154 Sfeeiieaioll for Plastics Ductwork
A9
A10
and air leakage classification for the y em under test
DESIGNERS CALCULATIONS The designer can middotaJculate with reasonable accuracy the predicted total loss from a ystem by
a) Calculating the operatin presure in each ection of the sy tern
b) Calculating the surface area of the ductwork in each correspondin pre lire s ction
c) Calulating the allowabl~ los at the operating pressure for each ection of the system (see table 13 for allowable leakage figures)
VARIABLE PRESSUR S IN SYSTEMS De igner can achieve significant co t saving by matchina operating pressures throughout the system to constmctional standard and appropriate air leakage testing eO the practice of specifying construction tandards for whole duct sy tems based on fan discharge pre sure may incur unnece sary costs on a project For example ome large sy terns ould well be classiC ed for I akage limits as follows
Plant room risers CJas C Main floor distriblltJou CIa B Low pre sure outlets Cla A
A6 SPECIAL CASES There may be ~itLlations on a project where circumstance dictate thal pecial consideration be given to containing air loss s eg a long mn of duclwork may incur a di -proportjonate level of air 10 s In ca es such as thi example the designer can specify an improved tandard of airtighmess ie 80 of alJo~able 10 s for la B Ju ts The designer sbould not specif a CIa C t sI at CIa s C pressure for a CIa s B ducl
A7 SUGG S ED RANGE OF TES ING
A8 TESTING OF PLANT ITEMS Items of inline pJant (eg Fig 106 to 115) will not normaUy be included in an air I akage test The dllctwork contractor may indud such itelllS in tbe te t jf rh quipm ot has a certificate of COnfOlnlity for Ihe pres ure clas
bull High pressure duct bull Medium pre sure ducts bull Low pre sur ducts bull Exposed extract syst ID bull Ceiling void extract
systems bull Secondary ducts from
VAV or fan coil units bull Flexjble duct bull Final connections and
branches to grille and diffusers
100 test See A5 Untested UDt sted
Untested
Untested Untested
Untested
SI
i
DW154 SJecijicafion for Plastics Ductwork
ig 116 Permitted leakage at various pressures
Leakage in litres per second per square metre duct surface area
Vgt
o ltgt 0 ltgt N
ltgt Cgt
0 0 cc
0 0
~
g =
g ~
c 0
J
ltgt 0 I
~ ] tn
ltgt ltgt
In ol
~ 0 ~ 8 ~
~
c ltgt ltgt
~ CJ
~ ~ ~ ~ 8
0shyij
~ ~ ~ t
ltgt ltgt 00
l
~
~ Q
c C
~ rshy
e ltgt
I 1
I Cgt ltgtv
c Co ~
~~ ~ 10
I
0 Cgt
fJshyq 410 ) 1 ltgt
ltgt N
~ shy ltgt ltgt
~ I 1
c
52
DW154 Specificatio for Plastics Ductwork
Example of a completed test sheet Test No
General
Name of job N~ jC43Pt(r2lef Building Repound ~(~~0
Part 1 - Physical details
a Section of duct work to be tested ~(diffPIfff~el1f3rd Floor
b Drawing Number g91~~ c ssure aSSJ L atlOn V~Jl~IRfYgtg~~lPre Cl T Class C
d Test static pressure -(9 raErq~ ~~~~-~~J~~~ ~~ ~~~~ll
Leakaoe factor 9~-tre3$ecMz I OM REFTOTABLE 13)e b bullbullbullbullbullbullbull
f Surface area of duct under test Q~tJJItetre$ CPROMCALCU TIO BELOW)bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull ampampamp bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull
g ]Vlaxi mum permitted leakage -~ (~i~~0 ~~r~~ ~~~l-~-11~ ~~~Q
Part 2 - Test particulars
a Duct static pressure reading 9QFt~q~ ~ middot~~~1 ~~
b Manufacturer and type of liow measuring d vice (-~~~cJ~Y-9Q7EYg c Range of measurement of now measuring device QtP)OQ~(e~~~0I~~~~1~I~ ~~~~~~W~
d Reading of flm measurin o device pmiddot IFROM RIO)ftscag ~
I (DERlVED [ROM CHART SUPPUED WITH RIG US 0 ud)1e Interpreted air flow leakage rate ~(~~~f~~~ (~l~~~~~~~~~~~~~~~~~I
f Duration ~~~~~norn~allY l~ lnil1Ut~~d~~~ it1~ W~ Date of test ~(lITled ut by Wltll s ed by ~ ~
(~lJ MIJLrr) (Si~rrfltJUYJ
Printed Name 1~g0f~ Printed Name ~~Y~9~ and Company 7jl~~~~~( UJd CompanY AB COII$Itallt8
Width and depth or diameter
Periphery ength Area
millimetreS millimetres metre qL1are metre
800 x 750 3100 1755 5440
600 x 650 2500 557 1193
300 x 300 1200 120 144
305 din 958 700 670
250 dia 785 450 353
TOTAL 8000
53
DW154 Specijilarion for Plastics Ductwork
pA XB
Guida ce No es For he ransport Handling and
Storage of uctwork
avoid damage to adjacent duct panels In somc ca es particularly on con acts calling f r repetitive sizes the use of timber jigs and spacers may be justified Where reduced bulk and greater protection are major factor such as consignments for export transporting ductwork in L shape sections may justify the increa ed ite as embly co ts
It is recommended that before a contract is finalised that consideration is given to the subject of site acces material handling and storage as tbcy havgt a strong influence on the cost efficiency of the overall activity of ductwOlk installation
B3 Handling To minilnise th risk of damage duct sections should be clearly identified and deliveries to site should be closely linked to the installation programme so as to avoid accumulation of
B1 Storage and Handling of Ra Material Material should be stored in suitably designed racking out of direct unJight Where possible the e racks should be metal to earth Edges of cut she t may be harp and protective gloves are advised Wearing teel toe-capped boots is recommended Most pIa tic sheet is manufactured with smootb mfaces andor is suppLied with protective coating Care must be taken to prevent accidental lippag of stacked materials Beiuoshy good electrical insulators the movement of stock unless earthed will allow the build up of stati All stock shapes are chemically stable at normal temperature Whil t some raw materials used in their manufacture may themselves pre ent a toxic hazard once incorporated into the lOck bape they no long r constitute such a hazard and no dermatitic bazard are known nor are any
unfiJied ductwork and minimise double handling It is important to recognise that ductwork panels joint and corners arc susceptible to damage and care must be taken wheu band ling such material through a site During handling individual item of duct work may be liable to light cross sectional deformation until thev become an integral pan of a completed ductwork system Whilst this may temporarily detract from its intended appearance thi deformation will not have any detrimental effect on the functionality of the finally a semblecl system Installation of duct work and asociated plant items ill illevitably involve manual handUng The responsibi Iiry of employers and employees to a ses the risk of personal injury during mallual handling operations is et out in the HS E publication L23 Guidance on Manual Handling Regulations 1992
environmental problems expected 84 Site storage
B2 fransport Large capacity vehicles with high-sided open or closed-top bodies are tlle mo t suitable for the transport of dllctwork Careful consideration should be given to the
Adequate floor space IDust be provided within tbe building for the site storage of ductvork Such storage shalt make due allowance for thc stOf(ne of ductwork in stacks such that access ~ egt
between them is of sufficient width to pennil the removal of item without interference to
unloading of transport on sit a not all siJes b n fit from the material handlino- and access facilities that exi [ in a manufacturing workshop such as crane- fork-lifts or loading bay Site handJiog facilities along with
adjoining sta ks Ductvork components should be positioned so a to avoid crushing Ductwork of small panel size may be stored horizontally however care should be exercised to ensure that tack sizes are limited 10 within
ehicular acce s restrictions may itilluence the type and ize of transport to be uWised
engtlls of ductwork should be positioned 0
the tmctural strength of the duct sections to prevent distortion of the lower sections within the stack
as to avoid crushing Lengths Witll projections such as branches and bends i1anges girths damper quadrauL should be loaded so as to
54
DW154 S1tciic(ltioll for Plastics Ductwork
85 Internal cleanliness of new ductwork The site storage of ductwork introduces the important cODsideration of maintaining the internal cleanliness of the ductwork R feren e should be made to HVCA documentshybull DWffM2 Guide to Good Practice - internal
Cleanliness of New Ductwork Installations If the above conditioDs can not be satisfied consideration should be given by tJle designer to amending the specification to include for Po t Installation Cleaning as covered by tJ1C HVCA documentshybull TRJ17 Guide to Good Practic - Cleanliness
of Ventilation Systems
APPE DIXC
Fi e Retardant inishes C1 Improvement in the fire retardancy of plastic
ducts can be achieved to varying degrees and is wholly dependent llPOll the surface coating laminating resin selected and construction specification adopted In some instances smoke emission is coILSidered equaUy with other speci fication requirernen ts of the materials resistance to ignition and bumjng It is therefore important for design rs to establ ish the clients and officers detailed requirements and not rely on a tbird party interpretation of fire resisting or fire retardant Where possible the specification should refer dir etly to compliance with a British or European Standard identifying the specific sections applicable There are various types of resin and mat rcLnforcements that can achieve a Class 1 surface spread of flame ratin o when tested according to BS476 Part 7 (1987) This test puts materials illto Class I - 4 in descending order of perfoDllance according to the rat and extent of flame spread over their surfac under standard beating conditions Materials should also be tested for flre propagarion to BS476 Part 6 (1989) Tbi tesr measures the amount and rate of heat evolved by the material when subjected to standard heating
conditions Test results are given as an index of Perfonnance (i) whicb is based on three sub indices (iJ (i1) (h) The higher the value of the Index of Performance (i) the greater is the material s contribution to fire growth The higher the value of the sub-index 0) rhe greater the ease of ignition aod flame spread The highest product performance classification as defined in Approved Document B of the Building Regulations is Class O This is acLlieved if a material surface of a composite ploduct i~ either a) composed throughout of materials of
limited combustibility or b) a Class I material which has a tlre
propagation index (i) of not more than 12 and sub-index (i l ) of nor more than 6
01 J Class 0 is not a cla$sif1cation identified in any British Standard test
There are resin system reported to be classified to Class O when tested to BS476 Pcl1S 6 and 7 however designers need to ensure that such sysrems can be applied to their proposed design In propriety resinmat system available the fabrication techniques and COITect application are critical to the integrity of the reinforcing and clas ificatiol1 For example in some systems the u e of a non-fire retardant gelcont on a fire retardant substrate would reduce the classification For further information see HVCA publication DW144 Appendix D
55
DW154 SplCijiClIliol1 for Plastics Ductwork
x Guidance otes For nspectmiddoton Servicing a d
Clean-ng Access Openings
D1 GE ERAL This appendix highlight in ummary fOI111
the acce considerations that hould be made by the design r iD terms of inspection servicing and cleaning Having considered the seop and the design of the dUCI work system relative to the guidelines outlined below the designer should clearly indicate which levels of acces should be incorporated into the manufacture of a new duct work system (See Table 14 and Note I b low it
D2 DESIGN CONSIDERATIONS
D21 In ptction and servicing requireshyments are set out in Section 15 of Lhis specification
D22 Cleaning requirements are set out in the HVCA pubUcation TRl7 Guide to Good Practice Clean Lines of Ventilation Systems and the guide tates The precise location ize and
type of access would be dependent on the type of ductwork cleaning inspection and te ting metbods to b adopted Care protection and standards of cleanliness prior LO cOlllmisionin o
are set out in th AV A publication DWITM2 Guide to Good Practice Internal Cleanliness of New Ductwork Installations and th guide state Wh re specific limits of cleanliness are required ductwork sball be cleaned after installation by a spcialist cleaning contractor It will b in the interests of tht desioner botb financially and practically to cunsider employing a specialist c1eauing contractor at tbe
outset of a contract to internally clean newly installed ductwork prior to bandover This approach would reali e the following benefit shyi) Tb actual numb r of cleaning
access panels could be detennined to suit the method of cleaning to be adopted (This may be 1 s than the maximum requiremen listed under Lev 13 of Table 14)
ii) Clear directions could b given to the ductwork contractor as to tJle size and location of cleaning access panels that are required to be fitted during the mauushyfaclunng pro s
iii) The specialist cleaning operation prior to commi ioning vould enable the cleaning contractor to verify the practical acee requirement for the future cleaning operation associated -vitb a regular maintenance programme
iv) A specialist cleaning operation prior to commissioning would allow the designer to omit from the speeilicatiolJ the DWrrM2 requirem nt for factory sealing protection wipe downs and capping-off
v) Specialist Ieall ill 0 to the measurable standard defin d in TR17 will allow an objective definition of cleanline to be achieved
Car ful consideration must be gIven by the designer to the practl aJ problems associated witb the manufacture and fitting of suitably si Led access panel on small cross section duct and on the circular faces of rouod and flat oval ducts in particular
D23 Special con ideration must be given by the de igner to the practical problems associated with gaining personnel access to heavily congested ceiling areas and multi-la red du twork systems This approach would avoid
56
DW154 Spfciication for Plastics Ductwork
the possibility of access panels being D3 ACCESS 0 IN-LINE EQUIPMENT incorporated into a ductwork system at the This appendix unly covers acc il1spection manufacturing stage that were later found in through the ductwork body adjacent to an item practice to be inaccessible for either ervicing of in-line equipment and not openings in the or cleaning activities equipment itself
able 14 Acce requirements for inspection servicing and cleaning
HVCA PUBLICATIO REFE NeE (uidtgt 10 Gund Prartict
Adjace t OW144 Cleanliness orVcnlillltio S~lcr~ fRjJ7
in-line LeyeJ 1 Level 2 Level 3 ite sequipment pcdionSen lcin~ Section d C1eaniJl( SUn(O)lnspc lion Palle ltk~m_n
2011 (minimum OiL Jubje-ct to duct ~zel (ft~ -Panels
Control Da pcrs One (inspection) 203 One 300 mm x 200 mm Both sid Fire Dampers One (sCTjdJl~) 20211 One 300 0101 x 200 mm One side HeatingCooling Coils One (inspedion) 20213 One 300 mm x 200 mm (lIpstream) Both sides Attenuators (rectangular) None required One 300 mm x 200 mm (downstream) Both sides Attenuators (circular) one retluired One 300 mm x 200 mm (downstream) One side Filter Sections One (inspection) 20212 one required Uoth sides Air Turn Vanes None requjred None required Both sides Changes of Direction None required one required One side In-Duct FansDevices One (inspection) 20213 None required Both sides l
1 In the absence of any indication by the designer only Level ) access will be jncorporated into a new ductwork system
2 Tbe panel izes associated with Lev lis I and 3 acee s ar e middottablished by reference to Section 20 of DW144 and Section 2 ofTRll7 respectively
57
DW154 Speclfifatio for Plastics Ductwork
pA XE
B-bliography Included in this Bibliography are technical pUblications which may be of interest (0 ductwork designers fabricators and erectors and to tho e in the heating ventilatlng air conditioning industries generally nquiric should be made of the relevant organisation at the address quoted Since its publication other addresse contained within 0V154 mav have changed and some pubJicalions may have been superseded
HEATING AND VENTILATING CONTRACTORS ASSOCIATION
4 Palace Court London W2 4JG Telephone 020-7229 2488 Fax 020-7727 9268
Orders fo FlY A Publications Old Matlsion House Eamont Bridge Penrith Cumbria CA 10 2BX (Telephone 01768 864771 Fax 01768 86718) Email hvcapoblicationshvwelfarecouk DWn 44 pe ilicatiun for sheet mctal duclwork (Iow- mediulllshy
and high-pressure) 1998) DWIl4 A practical guide to dUGI ork I akage te ting
(revised 2000) DWII54 Specification for plastic~ duct rk DW171 Guide to good Practice for kitchen venlibtion system DW191 Guide to good pracuce glass fibre ductwoJk DwrrMI Acceptance cheme for new products - Redangolar cro
joint classification Guide to good pra tice - Internal cleanliness of new ductwork installations Guide to good practice for the design for the Installation of lire and smoke uampers
J 1Other puhlications
HampV safely guide 5th edition JS2 Tool box talks JS5 Weldlng Safety booklet JSI9 afety facts bo klet Fact sheets 1-24 2nd edition JS2J COSHH manual volume 1 Advice on compliance with the
regulations 1521A CO I-rH manual volume 2 Asses mcnt h ets JS23 Ri k management manual TR3 BrazinltT and bronze welding of copper pipework cUld sheet
(I 976) TR5 Welding of carbon steel pipework (1980)
TR6 Guide to Good Practice for Site Pre sure Testing of Pipework (19 0) Guide to good practice cleanliness of ventilation Ylem
CHARTERED IN TITUTlO OF BUILDING SERVICES E G EERS Delta House 222 Balham High Road London SW12 9BS rTelephone 020-8675 5211 Fax 020-8675 5449) CIBSE Guide Volume A Design Data Volume B In tallatiol1 and quipment Data Volume C Reference Data
CommlssioniJIg Codes These Codes eover the preliminary checkS eUing to work and regulation of vanous catcgories 0 plan The Codes give a guide to design implications Series A Air Distnbution Systems Series B Boiler Plant
ri s C Automatic Conlrol ystems Cr1es R Refrigerating Sy terns
Sene iN Water Distribution Systems
Technkal Memonllda TM 4 Design Notes for the Middle East TM bull Design otes for Ductwork TM 13 Minimi iog lhc Risk of egiounaires Disease
Research Reports RROI95 Ventilation system hygiene - A review of published
infomlatioo on lhe occurrence and ffects of Olltamination Rl~02J95 Air-to-air heal rec v ry RR0395 rnfluen e of HV C on smoke detectors
ATlONAL ENI [ERING SPECIFICATION LfMITED Southgatc hamber 3739 Southgate Street Winchester S023 9EH (Telephone 01962 842058 Fax 01962 R(8982) BUfLDING S RVICES RESEARCH AND [ ORMATION ASSOCIATIO Old Bracknell Lane West Bracknell Berkshire RG 12 4AH (Telephone Brackl1eU (01344) 426511 Fax 01344 487 -7 )
Application Guides AGln4 De tglJing Vana~le Volume middotylans for KOOnl
iir Movement AG1I91 Commissioning of V Sylcms in Buildings 11 6194 Fire Dampers
B) 94 cntiJalion or KitcneTls
AG389 The Commls ionin of Air Systems In Buildmgs AH2192 Commissioning of Bern - A ~ode of Practice TN2417 I Fire Dampec il) Ventilating Ducl
BEATING VENTILATING A AIR CONDITION G MA UFACTURERS ASSOCIATIO (HEVAC) HEVAC Henley Road Medmenham Marlow Buck SU 2ER (Telephone 01491 578674 ox 01491 575024 Emoimiddot infofetacouk)
Publicatjons Air Diffusion Guide Guide to Air Handling Unit Leakage Testing Guide to Good Practice Air Handling Unit Real Room Acoustic ~ st Procedure Specification for the ertiiicatioll ofAir Filters Method of Test for Water Rejection PerfOnTlatce of Louvrcs Subjected 1(1
Simulated Rainfall Test Procedure for Acoustic Loo cs Specification 10 Floor GrilJes - Types Performan e and Method ofTest Specification for the Determination of the Collection Efficiency of SilJ1d
Trap Louvre Domestic Mechwlical Vclltllalion Systems with Heal Recovery Fan Application Guid
~an and Ouctwork Installation Guide Guide to Fan Noise and Vibration
pecification of Requirements for JallJral Smoke and Heal Exhausl Ventilators
pecification for Powered Smoke and Heat Exhaust Ventilators
Specification of Requirements for Smoke Curtains Design Gujue of Smoke Ventilation for Single Storey Lodustrilll Building~
Including those with Mezzanine Floor and IIi Racked Storage Warehou es - Issue 3
Guidance for the Design of Smoke entilation YSlem for Covered and Undergrollnd Car Parks - lssue 1
Application of SOloke Control Equipment and Syst m Guid to Good Practice - Isue J
58
DW154 Sp(C~tiifitiol for Plastics Ductwork
BRITISH STANDARDS INSTIT TION Sales Department 101 P ntooviLle Road London NI 9ND (felephone 020-78 1 78801)
CP 413 1973 Ducts for building ervices
SS 476 Fire tes on building matenals and lruc(ure
Part 4 19 4 Non-combustibility lest or materials
Part 6 I Fire propagation lest for materials
Part 7 1993 Surface spread of tlarnJ tesls for materia
Part 20 1987 Fir resistance of elements of construction
Part 21 1987 Fire r sistlUlce of loadbeanng elements of construction
Part 22 1987 Fhe istallceofllon-loadbearing elemcllts ofconsttuclion Part 23 1987 Contribution of componcnts to the fire resistance 0 a
structure
Part 24t987 Fire resi lance of wl1lilation ductl
SS 5588 nan 919 0 Fire Precautions III thc desIgn and OOSlnJ lion of buildings
S 729 1971 Hot dip galvanized oatiugs (or irOIl aod stcel articles
BS 1449 Steel plate sheet and Irip
Pan 11991 Carbon steel plate heel and strip Part 2 1983 Stainless steel plate sheer and strip
and
B middotENJOI49-2 996 BSEN 10149- 1991)
BSEN 10131 1992
BSEN22063 Sprayed metal coarings 1994 Protection of iron and steel by aluminium and zinc against
atmospheric cOlosion Irotectiotl of iron and ste I against corro ion and oxishydation at elevared temperatures
BS 353 1981 Glossary of lerms relnting to thermal insulation
BS ISO 1479 Self-tapplngscrewsandmetallicdri c crew
B -lSO 7049
1994
B 4800 1989 Painl colour for building purposes B 4848 l0 rolled structural steel sections
Part4 1972 Equal and unequal angles BS 5422 1990 Specification for the use of therm illuating matcriulS
SS 5720 1979 ode of practice for mechanical veutilating and air C 11shy
dirionin bull in building
l3S PR 12814-1 Bend resting for plasric welds
SS PR 12814-2 Tensile testing for plastic welds
SS PR 13067 Appro altesting for plastic welds
BS PR EN I 100-] Vi ual in pection ofplaslic welds
SHEET METAL AND AIR CONDITIONING CONTR-CTORS NATIONAL ASSOCIATION INC (SMACNA) Headquarters 420 I Lafayeue Center Drive Chanlilly Virginia 2051-1209
Mailing Address pa Box 221230 Cbantilly Virginilt120 153-1230
Telephone (703) 803-2980 Fax (703) 803-3732
Accepted IJJdustry Pl3Gtice for Industrial Duct Constnlelion 197 ) i-rchitecmral Sheet kwl Manual ([993)
Comractors Guide lor Modification 10 ooslruerion Colllraets 1993 Ducted Eleclric Heat Guide for ir Handling Ssrerns (1994)
En~rgy ollservatioD Guidelines (1984) Energy Recovery Equipment yslClllS (199l
Fibrou GIns Duct onS1ntClion Standards (1992)
Fire Smoke amp Radiation Damper In tall Guide for HVA Syst ms (1992) Guide t leel Stack 1(95)
HVA Air Duct Leakage Test Manual (19 ) HVA COlllmissioning lvlanual (1994)
H A Duct Construction Standards-Metal amp Flexible (1995) Addendum 01 (Nov 1997)
HVA Duct Systems Inspection Guide (1989)
HVA ySlems-Application (1986) nVAC ByternS-DLlct D ign (1990)
HVi Systems-Testing Adjusting amp Balancing (1993)
indoor Air Quality Manual (1993) tcheu quipment Fabrication Guidelmes (1990)
Managers Guide for elding (1993)
Rectangular Industrial Duct Cons1TUction Standards (19 0) Round Industrial Duct oustmction Standards (1977)
Sei mic Restraint Manual (1991) (wl Appendix E 1993) SMACNA Ma le Index ()fTechnical Publications (1995) Tbennoplnstic Duct CPY ) Construction Manual 1994)
DEPARTME OF THE ENVIRO MENT (Publications Centre) H Stationery Oflice 5 Nine Elms Lane London SWS 5DR
MampEJ 011972 Electrical in tallat1011 in buildings ( ew Editiou)
IampE 0319 Healing hot and cold wat r steam and gas losla1lations for buildings
M amp - No4 1970 Central heating and hot and cold ~ ateT in tallations for
dwelling
M amp ENo100 1971 Mechanical ventilation for building~
ASSOCIATION FOR SPECIALIST FIRE PROTECTlO As ociation House 235 Ash Road AJdershot Hampshire GUl2 4DD
Telephone OJ25221322 Fax 0 J252 333901
lublicalioos Fire Ratcd and moke Outlet Ducrwork An Industry Guide t Design and InSlalla lioll
HEALTH AND SAFETY EXEC TIVE Rose Court 2 Southwark Bridge London SEl 9HS Telephone 020-7717 6000
TWJ THE WELD G TlTUTE Abington Hall Abington Cambridge CB16AL Telepbone 0 J223 89162
Publication DatJ Oil w~ldll1g of lhermopla lics
59
DW154 wciiwlioll for Plastics Ductwork
A -=--DIX
Factors
Specific gravity shy pp = 091 approx UPVC = 14 approx
Some miscellaneous conversion factors
To convert
Length Inches to millimetres Feet to metres
Multiply by
2540 03048
To convert
Millimetres to inches Metres to feet
vIultiply by
003937 3281
Area Square inches to square millimetres 6452 Square millimetres to square inches 000155 Square feet to square metres 00929 Square metres to square feet 10764
Volume Cubic feet to cubic metres Cubic feet to litres Gallons (UK) to litres
002832 2831 4546
Cubic metres to cubic feet Litres to cubic feet Litres to gallons (UK)
35315 00353
022
Mass Ounces to grams Pounds to kiJograms Tons to tonnes
2835 04536
1016
Grams to ounces Kilograms to pounds Tonnes to tons
003527 2205
09842
Volume flow Cubic feet per minute to cubic Cubic metres per second to cubic
metres per second 0000472 feet per minute 2119 Cubic feet per mIDute to litres Litres per second to cubic feet
per second 04719 per minute 2119
Motion Feet per minute to metres per second 000508 Metres per second to feet per minute 197
Pressure Inches water gauge to millibars 2491 Inches wateJ- gauge to pascals (Pa) 2491 I Pa = I ewton per square metre = 10-2 millibars
60
Heating and Ventilating Contractors Association Esca House 34 Palace Court London W2 4JG
Tel 020 7313 4900
e-mail contact Itvcaorguk web site wwwhvcaorguk
Fax 020 7727 9268
DW154 Specification for Plastics Ductwork
6PA deElned in J62 appropriate to the airflow pressure acoustic temperature and corrosion
General
15 ACCESSl SPECTION OPENINGS
151 General These are for inspectionservici ng on 1y
HVCA publication DWIl44 Part 7 - General Section 20 sets out the requirements for access applicable to this specification
152 Cleaningmaintenance Designers shall take specialist advice and then stipulate their requirements for the periodic internal cleaningmaintenance of ductwork and of the consequent need for adequate access for specialist cleaning equipment including the size type and locationfrequency of the actual access openings required
Appendix D sets out guidance notes for the consideration of cleaning access and also makes reference to the HVCA publication TR 17 Guide to Good Practice Cleanliness of Ventilation Systems which covers the su~ject
in greater detail
Note A majority of in tallations in which plastic ductwork is used are considered to have a nigb operational risk potential and provision of access should address this
16 REGULATI G DAMPERS
161 General Balancing dampers and control dampers are elements inserted into an air di tribution system or element of an air distribution sy middottem Balancng dampers permit modification of the air resistance of tbe system and consequently cbanging of the airflow rate Control dampers control tlle airflow rate and may in addition provide low leakage closure of the airflow
The deigner shall specify damper locations taking into consideration that good design practice requires a minimum of five times the diameter or width of the shortest side of uninterrupted flow between plant connections and the damper and select the damper type as
characteristics
1611 Balancing damper To achieve the required distribution of air in the ductwork system at inlets andor outlets for [hi purpose the damper blades are set and Jocked manually in position between fully open and fully closed
1612 Control damper To secure dynamic control of the air now in the ductwork system In thi function the damper will always be power actuated and may require to be modulated between fully open and fully closed and to be capable of taking up any position between these extremes In the fully open position the damper should have a minimum pressure drop In the fully closed position it will not necessarily achieve a complete shut off
162 Types of airflow control dampers Airflow dampers of various types are available for specific purposes as follows
1621 Single - blade dampers Single-blade dampers shall consist of a si ngle pi voted blade cOlllained withjn a casing or section of ductwork The blade shall be adjustable tbmugh a nominal 90 angle by means of a quadrant or similar operating mechanism Where automatic control of the damper is required the spindle shall be extended to enable a powered actllator to be mounted
Single-blade dampers shall have a maximum duct width of 400 nUll and a maximum duct height of 400 mm for rectangular ducts and for circular ducts a maximum diameter of 400 mm
1622 Multi-blade dampers Multi-blade dampers shall consist of a number of pivoted blades contained within a casing The blades shall be
22
DW154 Sedicalirm for Plastics Ductwork
adju table through a nominal 90deg angle simultaneously by intershyconnected linkage or gears connected to a quadrant or similar operating mecbanism Where automatic control of a damper is required a spindle shall be extended to enable a powered achlator to be mounted
There is no restriction on the size of duct in which multi-blade dampers or damper assemblie may be u ed Where dampers are required for blade lengths in excess of 750 mm the blades should be suitably reinforced or supponed 0
individual damper blade should exceed 200 mm in width
1623 Iris dampers Lris dampers shall consist of a nUlllber of radialty interconnected blades which open or close within a casing with duct COlll1cctions The blade shall be simultaneously adjusted by a quadrant or similar operating mechanism
Iris dampers shall be installed as specified by the manufacturers operating and installation instructions where the product is unidirectional with regard to airflow
lris dampers are available for circular ducts only in diameters up to 250 mm (it should be noted that the damper casin i appro)(imately twice the diameter of the duct)
1624 Backdraught dampers Air pressure operated uni-directional rectangular (single or multi-blade) with adapters if fitted to circular ducts
1625 Slide and blast gate dampers A damper [lsed as a shut off facility with an externaJ Lide bousing allowing the blade configuration to be fuJly inserted to fully extended for maxiDlUlll air flow
163 Construction
1631 Materials All products shall be protected against cOHosion as necessary and supplied in a fully finished condition as specified by the designer
1632 Dampers used in low and medium pressure systems The following recommendations apply to dampers forming an integral part of ducrwork with pressure classifications A and B air leakage limits
The dampers shaH be constructed to minimise distortion and prevent jammin in operation Th blade shall be sufficiently rigid to minimise movement when in the locked pOSitiOLl
The blades shall be securely fixed to the operating mechanism All balancing dampers shall have a locking device located on the outsid of the case and shall giv clear indication of the actlwl blad position All penetrations of the duct shall be fitted with suitable seals where necessary
1633 Dampers used in high pressure systems Regulatino- dampers used in duc[work sy tems to pressure cJassification C shall meet tbe construction requireshyments specified in 1631 and 1632 with operating mechanisms out of the air-stream
1634 Proprietary types of damper The use of any specific type of proprietary damper shall be confirmed by the designer In all cases proprietary dampers shall meet the relevant requirements of thi specification
1635 Damper casings Duct damper casings hall be constructed to meet th mllllmum
23
DW154 SpeciJimlioll for Plastics Ductwork
leakage Iim its sp cified for th c1uctwork ystem to which tbey are installed
In order to apply the square metre leakage calculatio as detailed in DW143 A Practical Guide to Ductwork Leakage Testing the reference casing area ball be taken as the perimeter ize of lh damper IDultipli d by the equi alent length of Imetr eg an 800 mm x 400 mm duct damper hall have a surface area for casillg leakag p donnan calculated as follow (2 x 08) + (2 x 04 x I
=24m2 casing area
Other pelforlllance ancl rating test methods for damp f and valves are specified in ISO 5129 and BSIE 1751 and are referenced belm a) Leakage past a closed damper
alve BSIE 1751 b) low ratepre sure requirement
characteri t cs BSIE 1751 c) Operational torque le ring
BSEN 1751 cl) Thermal transfer testing
BSIEN 17 I e) Reg nerated sound power levels
ISO 5129
164 Installation Dampers shall be imaalled in accordance will) any re Ievant ISO EN or British Standard 10 aJ bUT lcling regulation and national code of practice as well as the manufacturers recommendations
17 FIRE DAMPERS AND INT MESCENT SLEEVES
171 General Damper or sleeves arc requiTed on duct y~telll where the designer has -tjpulated the
duct wiU penetrate a fire compartment in the majority of application tbermopla ti ductwork is ugtecl where contamlDated corro ive or otherwise exceptional fumes are concerned it is preferable to use tire damp r which are externalJy mounted ie of the intmnescent operated crush typ
24
72 Fit-e rating The damper assembly should have a fUT
resi tance ratin o equal to that of the fir ban-jer it penetrate and ball be fire tested and rated to the timetemperature curv of B 476 Part 20 and 22
173 Intumescent sleeve At the time of writing this specification qualified test results were available for rectangular dampers and circular dampers up to 55 mm diamet r Manufacture have indicated that they are able t provide speci fications for other size and diameters This infonnation should be confirmed b th de igner Various type are available includino
tho e incorporating ruechanical closing plate and those operated anI by expanded iJllUme c nt media
In all ca es fire damp rs and intnmeBcen leeves shall be supplied and in taUed in
accordance with the manufacturer iJlStructioos and COSHH a essm nt
174 Other types Fire dampers of mious types are availabl for specific purpose~ ee HVCA publication DW144 The de igner should )lot (hat materials for con lt1Jction bould be uitablc for the par1icular application
ALL C SES FIRE DAMPERS AND fNT MESCENT SL _VES SHALL HE S PPLTED AND INSTALLED IN A ORDA CE WITH Tf--IE MANUshyPACTURERS STRUCTTONS AND COSHH ASSESSMENT
18 FLEXIBLEEXPANSION dOINT CONNECTIONS
181 General ploperties Tbe material u ed for flexibleexpan ion iojnt~
mu t meet the design r requirements for temperature air pressllrelfe resistance applicable to pl astic duct sy tem vibration and noi e br akout when incorporated into a jointconnection and shall comply ith lh standard of air-tigbtne specifi cl for the duct work sy tem of which it fOlms part (See Figs 23 24 5 26 27 amp 28 for typical con truclion clelai Is
DW154 SJecilimtol for Plastics Ductwork
Expansion joints
Fig23 Moulded bellows type (rectangular and circular)
Fig24
~F aiblc sleeve
__ liding sleeve
~~~~
Sleeve type (circufar)
Fig 25
AIRFLO
COnlinuou~
weld~
Flexible Iceve
PV A HOWN pp SE BACKING FLATS AS FIG 2
Sliding lee c Co1linuou
weld
Flanged sleeve (rectangular and circular)
25
DW154 Specificatiol for Plastics Ductwork
Flexible con ections
Fig 26 Flexible sleeve with clips (UPVC and PP)
--__ Flexible I eve
I
I
I CODn clioD to plant ~
Band clip
Fig27 Welded flexible sleeve (UPVC only)
Plastic)sed PVC slceve ~-- onll11uo1sly welded
onrreclion to planl ~
Fig28 Flanged flexible connection (UPVC and P )
t sp dally moulded flexible flanged connCClitlll
boil
C)nneclion to plant ~
26
DW154 Specificotiol for Plastics Ductwork
182 LOClt1tion Flexible joint are typicltllly lIsed at building expansion joint and fan inletsoutlets Any others required should be indicated on the de ign drawings Care should be taken to maintain alignment across jointsconnections
183 Length Flexible Jomts shall be kept as short as pra middottieable above a minimum eft ctive length of SO mm In no ca e shall a flexible joint exceed 250 mm in lengtb
184 Connections to rectang a ducts With flanged rectangular connections Ule tlexible material shall be held in pLace with flat pIa tic strip of not less U1an 6 mm thick ltlttached to the flanges using uitabJe fixings The more heavy weight type of fleAible mateLial may also be obtained formed into a channel ection with corners fitted to give a neat air tight j int For pigot connections the Be ible material shall b held in place with flat pIa tic trips n t less than 6 mm thick
t 85 Connections to circular ducts With tlanged circular connections the flexibl material shall be held in place with flat plastic backing strips or proprietary clip bands with screw or toggle fast ners
186 Welded flexible connections (Rectangular and Circular) Where the parent and llexibl material are from imilar ba ed products they can be joined to the duct u ing the welding method described in Section 823
19 PROTECT VE FINISHES
191 nles otherwise stated all ductwork shall be mallllfactured in mat fial as pecified in tbis specification Any special coatingpaint fmishes to be provid d by the duct work contractor sball be advisd by th de igner
20 CONNECTIONS TO BUILDING OPENINGS
201 Fanning and finishing building op nings are not the repoJlsibjlity of the duftw( rk contractor and the note that follow are for guidance purpo e only
2011 Openings in brick block or concrete walls shall have inset frames to provide a suitable means of fixing grille louver masking flanges or the tlanged ends of ductwork The illset frames shall be conslnlcted to maintain the structural int grity of the wlll and where applicable cavities shall be suitably lined
2012 Openin s in dry linino partItIons shall have inset frames a 2011
2013 Openjngs in cladding walls and roofs shall have flaoged leevesframes to provide a suitable means of fixing a 2011
2014 Horizontal and vertical opening xposed to oLltside atmo phere hall
be provided with a suitable weathering fini h at the external face especially where profiled cladding is used
2015 Timber framed op nings are not permitted In fj re compart ment barriers
202 Ductwork connections to building openings hall have a flange of suitable profile to permit practical fixing to the openillg frame In selecting the profile consideration shall be given to Tabl~s 2 and 10 in this specitication relating to duct ize and rating Gasket strip or sealant shall be ltlpplied between the tJaoge and building op ning frame
21 DISCHARGEEXHAUST TERMINAL
21 Tbese shall be vertical open ended and designed to meet and comply with current r gularions on contaminated flue The designer hall ensure that the de ign and perf rmance i suitable for its intended purpose Examples of some typical terminal designs are SbOiD in Figbull 102 10 bull 104 amp 105
27
DW154 SpedjimioTl for Plastics Ductwork
22 THERMAL INSULATION
221 The provision and application of thermal insulation to ductwork is not the responsibility of the ductwork contractor
222 Where ductwork is required to be preshyinsulated the specification should be agreed with tbe designer
223 Where the temperature of the air within the duct promotes condensation on the exterior surface of the duct and cause moisture penetration througb the thermal insulation vapour scaling may be required and in this case the most important requirement is to limit penetration of the seal
The extent of any vapour sealing of ductwork thermal insulation and the support method to be u ed must be clearly pecitled in advance by the designer
224 For detailed information on the thermal insulation of ductwork reference should be made to BS 5422 1990 which covers the specification for thermal insulation materials on pipes ductwork and equipment (in the temperature range -40degC to +700degC) and BS 5970 1992 which is a Code of Practic for Thermal Insulation of Pipework and Equipment (in the temperature range -lOOdegC to +870degC)
23 FIRE RETARDANT FINISHES ON PLAST C DUCTWORK
231 The designer should note tbat ductwork constructed to DW154 has no teted fire rating or information see Appendix C
24 REINFORCEMENT OF DUCTS WITH GRP LAMINATE
241 General Where ductwork is required in larg T izes than are covered by Tables 2 4 6 amp 7 or with the increased strength sometimes necessary for industrial use external reinforcement is normally pwvided by applicatioD of glass fibreresin laminate
GRP systems will bond satisfactorily with standard UPVC sheet but for pp it is
nece sary to use a specially prepared sheet with a glass fabric backing incorporated dOling manufactllfe
The detailed techniques of fabrication using GRP are outside the scope of this speci lcation but the following notes are offered for guidance of ductwork fabricators
242 Materials
2421 Quality The laminate is made up of polyester resin complying with BS 3532 and glass fibre complying with BS 3496 or BS 3749 The nominal ratio of resin to glass fibre should be 7030 by weight
2422 Minimum properties The laminate shall comply with the followiog mini mum pbysical properties
Tensile strength - 70 MNm Tensile modulus - 7 Gl m Flexural strength - 140 M Im Bond strength (hetween laminate and substrate Not less than 7MNm Bmcol hardnes Not le s than manufacturers specification
The GRP reinforcement educe the expansion of the parent material but the resultant stre ses arc well within rhe strength of the bond However the Iinear thermal expansion curve shown in Figs 34 amp 35 will serve as a guide
Surface resistivity electrkal propcltles and acoustical propertie are similar to the relevanl unreinforced materials The fire retarding properties of GRP may be improved by the use of specialisl laminating resin
2423 Forms available GRP Laminate should be built up from the separate materials ie resin aod glass fibre in the form of chopped
I strand mat or spray ravings
28
DW154 Spcification for Plastics Ductwork
2424 Workshop conditions Polyester resuls are sensItIve to lmperature and the workshop hould b maintained at a temperature of herween 20deg and 25degC HiOh relative humidities and damp onditions should be avoided A good rate of air change must be pro icled pJeferably by m chanical ventilation
2425 Storage of materials Resin and urin o agents shouJd be stored in dark cool condirions away from the working area and in confonnit with statutor requireshyments for tJle middottorage of flarmnable liquid Because of Ule Limited torage lif of the unmixed resin and curing a eot mal lials ~hould be ch eked before use to enLlfe that they are within the manufacturer pe ified sh If life (usually ix month from the dm of manufacrure)
Glass fi re should be stored separately und r clean dry conditions
243 Surface preparafon
2431 UPVC To achieve the specified bond strengtll the urface to which the GRP is applied mut first be thoroughly cleaned and then etched either by mechanical means or by the use of a suitable solvent
2432 pp with glass fabric backing To achieve the specified bond middottrength the fabric backing must be thoroughly impregnated Witll resin
244 Mixing the materials for use The re in 1 a three part mix compri lng base I sin hardener and accelerator The manufactur rs pecj[ied proportions are critical and th llUxmg sequenc pecified must be meticulously foUowed
The resin has a very limited life after mixing and before u e It is dependent on the characteri tics and bulk of th resin the alllount of hardener the degree and method of acceleration and the workshop onditions
245 Methods of application
2451 General The mixed resin may be applied by hand or b pray c1epoition The operation must b completed within the gel time of th y tern and tbe laminat fully cOI1olidated to achi v the phy ieal properties pecified
2452 Hand lay-up The duct surface i coated by hand with resin Llsing a brush and a mar of gla fibp orked in until full consolidation achieved Th proc is repeated untiJ th requird thicknes i obtained
2453 Spray depo Won The duct surface is coated WiUl re in by spray gun with the chopped glass roving added through a separate nozzle The full thickne i obtain d in layer with con olidation of each layer by hand roller
246 Construction
2461 General M ini mum COllst ructional requireshyments are pe itied ill Tabl 10 for rectangular and Table 1J for circular dUClS
2462 Joints and stiffeners Fig 29 30 31 32 amp 33 hoI TOSS
joint and tiffener for reinforced UPVC and PBPP duct
247 Worki g practices The fabrication of ductwork pecifiecl ill thi document i not affected by the addition of GRP
29
DW154 SfJcdJicatiOt for Plastics Ductwork
Table 10 Minimum constructional requirements shy
Longer Side Minimum Sheet Thicknes and
GRP Reinforcement
UPVC FBIPP 1 2 3
mm mm mm Up to 1000 3 plus 3 plus
06 kgm2 06 kgOIl GRP GRP
1001 to 2250 45 plus 3 plus 06 kgm 12 kgm
GRP GRP
2251 to 3000 45 plus 6 plus 12 kgm 12 kgm
GRP GRP
Cross Joints
UPVCFBPP 4
mm socket amp spigot
as Fig 30 or flanged as Fig 29
75 x 9 flange welded on both sides as Fig 29
75 x 9 tlange welded on both sides as Fig 29
rectangular GRP reinforced ducts
SlifTeners Maximum Spacing Between
JointsSljffeners UPVCIFBIPP UPVCFBPP
5 6 mm mm
75 x 9 flat 800 as Fig 31 or
50 x 50 x 5 plastic or MS inverted angle as Fig 32
or tormer as Fig 33
75 x 9 flat 600 as Fig 31 or
50 x 50 x 5 plastic or MS inverted angle as Fig 32
or former as Fig 33
75 x 9 flat 600+shyas Fig 31 or 50 x 50 x 5 plastic
or MS inverted angle as Fig 32
or former as Fig 33
Note 1 On rectangular duct up to 400 mm longer side no stiffeners are required 2 Applies to Tables 10 amp I I For COlJstructional operating temperature limits refer to Part 2 clause 5A 3 Tables 10 amp II apply to all pres ure classes up lo ]500 Pa
Table 11
Diameter
1 III
lJp to 1000
1001 to 1750
1751 to 2500
Minimum Sheet Thickness and
GRP Reinforcement
UPVC FBPP 2 3
mm mm 3 plus 3 plus
06 kgm 06 kgm GRP GRP
45 plus 3 plus 06 kgm2 18 kgm
GRP GRP
6 plus 6 plus 12 kglm2 18 kgm1
GRP GRP
Cross Joints
UPVCFBPP 4 III
socket amp spigot as Fig 30 or flaoged as Fig 29
75 x 9 flange welded on both sides as Fig 29
75 x 9 flange welded 00
both sides as Fi 29
inforced ducts
Maximum Spacing Between
JointsStiffeners UPVCIFBPP
6 mm 2400
800
600
Stiffencrs
UPVCFBPP 5
mm 50 x 9 flat as Fig 31
75 x 9 flat as Fig 31 or former as Fig 33 75 x 9 tlat as Fig 31 or t()rmer as Fi 33
ote On extruded tube tip to 600mm diameter no stiffenergt are required
30
DW154 Specificatioll for Plastics Ductwork
G - Cross joints and tiffeners
Fig 29 Flange Joint Fig32 Stiffener shy inverted angle
M artiPfCuQkbdd erttpObri) Wl111 RP tlddtlt
_- GRPloliu] lh~
Fig 30 Socket and spigot joint Fig33 Stiffener shy use of former
Fig 31 Stiffener Flat
I Pv FlPP ~ ~lmJaDUA1) d
OMrlQ rrnall 1( tQlS
25 STANDARD COMPONENT DRAWINGS AND ABBREVIATIONS
251 The illustrations in this section not only highlight where applicable geometric limjtations for the de ign and manufacture or ductwork components but also recommend
standard drawing representation terminology and abbreviations for both duetwork components and some of the more commonly used ancillaryplant items
252 Designers and surveyors should note that bills of quantities should provide a full description
3)
---
v
DW154 Spcc(fim(ml for Plastics Ductwork
Fig 34 Linear Thermal Expansion
u c 0 N ro 0)
b 0)
S
sect0
5 oS cl) 0)
~
on ~ ltl
c U
-30 -20 -10 0 10 20 30 40 50 60 70 80 90 TEMPRATURE C
~ V
-
~~c_ ~
~V
V ~
-7 ~
-- ~V ----
v
-6
+14
+12
+10
+8
+6
+4
+2
0
-2
--4
ig 35 Typical Design Stress tor UPVC and P
7
6
r shy 5E
-c E----0 4t) VJ 0)
ci5 0Jl 3
~
0)
Cl
2
1
o
UPVC
1
000
1
1
pp
- r-- shy r----- shy - t--shy I
__0
-30 -20 -10 0 10 20 30 40 50 60 70 80 90 TEMPERATURE C C
Note Figso 14 amp 35 shaded area refers to GRP reinforced duct
32
DW154 Speciicfltirm for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - REC ~NGULAR
Splilt~r Posilion W-mm pliucr
A B c 40]--QOO 1 W - -
601-1000 1 W4 Wf2 -
1001-1800 3 WI W3 W2
FIG DRAWING DETAfiS
tU]36 ATI Straight Duct with socket and spigol joint
rn [037 Straight Duct with flanged joints
[I []38 Straight Duct with flanged joints
rkJ Short Radius Bend
39 Applies to any augl and for duct up to 400 n11n wide
Minimum (I1m31 radills = 100 mm
Medium Radius Bend (a illustrated)
[kJ Applies to any angle
40 Long Radiu Bend Similar but radius = W
Throlll radius = W2 Applies to any angle
- Short Radius Bend with plitlers
I -shy -shy u co - t lt Li--_ 41 t 0 ~ I I I
~ I
L 1W
Minimum waal radius = 100 mm Splitters not required in bend angle less than 45deg
42 QJ1 Square Bend with turning vanes ij
3
DW154 SP(L~ficatioll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - RECTANGULAR
FIG DRAWl G DETADS
43
~
I v
L L Radius Tee with internal deflectors
44
~ Radiussed Twin Bend
45
Imiddot
er Swept Branch
46 U-
Sqoare Tee with Turning Vanes
47
~ f
Breeches Piece
48 0 y l Piece
34
DW154 Specificatioll for Plastics Ductwork
STANDARD COMPONENT RAWINGS - ECTANGULAR
55
54
51
50
53
52
49
FIG
~MX
RAWlNG
DmiddotMAX
EfjMAX
Minimum throat rndius = 100 mm
Rectangular shy Round Transformatioll
Eccentric Taper 225deg max in either plane Spliller are required for angles greater than 225deg and hould bi eet the angle between any side and duct centreline
DETATLS
Angled Offset
OUset Taper Splitters are required for angle greater than 22 0
and shoold bi eet the angl between any side and dUCI centrelinc
Mitred Offset
Concentrk Taper 2250 max in ither plane SpUtters are required for angle greater than 225deg and should bisect the angle between any side and duel c ntreline
Radiussed Offset
35
DW154 Splcilcuthm for Plastics Ductwork
STANDARD COMPONENT DRAWINGS ~ RECTANGU AR
Branch ducl DimCllsions widlh (W) (A)
urnl mm up lO 200 75
300 100 400 125 600 150
Ocr 600 200
FIG DRAWlNG DETAILS
56 poundplusmni~~ Rectan~lar - Flat Oval Transformation
57 [ Square Branch
58 er Angled Branch
Branch dUCI Dimensions wfdth (W) (A)
[- mm mm59 3shy Shoe Branch Up (0 200 75
--shy AIshy + 300 100
400 125
450 MAX 600 150
Over 600 200
Branch duct DimensIOn
rP X width (W) A)
60 - 1--shy _
~ mm mm
Bell Mouth Branch pto 200 75 300 100 t 400 125
600 150 Over 600 200
0=0 61 -
~ Bell Mouth
- shy T 4-5deg M x
--I 1-shy
TJ
62 X I ] I
Tele-scopic Joint I Illustrated with flangeL
X63
SBD Single Bladed Damper
36
---
DW154 Spedicatioll for Plastics Ductwork
STANDARD OMPONENT DRAWINGS - RECTANGULAR
DRAWING DETAILSFIG
64 on-Return DamperNRD shyshy
shyXbull
Multi-Leaf Damper Can be piggoted or flanged oppo cd or parallel blade
Alternative controls areshy
q p [gtshy
J HD65 Hand
~MD otori ed
PO Pneumalic
L-lt
l 13G 66 Blast Gate DamperX X
FireSmoke DampersSleeves
211r Ratinggtshy----
L_-
---
----
r----
Ir-- shy
IL- _-l
2hr
With i tallation frame
67 41 r Rating
4hr
Smoke damper SD
Intumc cent Sleeve L-d
37
DW154 Specijicutiolt for Plastics Ductwork
FIG
68
69
70
71
STANDARD COMPONET DRAWINGS shy REC ANGULAR
DRAVING DETAILS
gtshy Access Openings
AP 6 Access Panel - Rerno able
w [ ~ Access Door - Hinged
I ~le Inspection Cover
le -I reg -lt
~X X Flexible Connection
~ Drop Cheeked Radiussed Twin Bend
U Drop Cheek Bend
I
72 Air Flow SymbolX
38
DW154 Specifim[ioll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - ECTANGULAR
FIG DRAWING DETAILS
73
74
75
76
77
Q
Q
rp---t
~
V- I Ir---I
JL --11
THE ABOVE DETAILS TYPICAL PLENUM
Air Terminal Plenums
Plenum with side connection
Plenum with top connection
Cover plate with connection
Special plenum with connection
elescopic conn ction in direction of air flow
39
DW154 SpecijicotiOll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG
78
79
80
81
DRAWING
-23~---pound3-(MALE) (FEMAJE)
-t=j--_j(--d-shy
--L
~ THROAT RADI S= D AS T NDARD
e ~
THROAT Rjf)lU = D A MU)
DETAILS
Straight Duct With male and female connectors
Straight Duct With flange joint and slip joint
Bend MouldedIFormed Applies to any angle ego 30deg45deg60deg90deg Medium radius bend as illustrated Long radius similar but throat radius 0
Segmented Bend 90deg four section minjmum as illustrated
Other Angles 60deg = 3 sections 45deg = 3 sections 30deg = 2 sections
I
i
40 shy
DW154 Speciicafinll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG DRAWING DETAlLS
82 Segmented Twin Bend Radius = D2 max
May also be fabricated from tube
83 Equal Tee MouldedIFormed
84 -~ 1in Bend MouldedIFormed
85 Taper Concentric 1 0 as iUu trated Eccentric 30deg iJJcLuded angle
86 Short Taper
41
DW154 SpcUicatol1 for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG DRAWING DETAILS
87 30 max Offset
Angle Branch
Bran h dUCI Dimcnsions dia (D) lA)
Shoe Branch mm mm 88 Cl
Off rectanguJur Up 10 200 75 lOO 10 400 125
- 00 150 Over 600 200
Bl1IllCh duct DimenlOns din (D) (A
~-$a-Conical Branch mm mm
89 Also acceptable with Up 10 200 r
full conical surface 300 10
400 125
END VrE -shy 600 150 Over 600 200
90
m 75
100 12 150 200
mm Up to 200
_ 300 400
600 Over 600
iUtred Branch
Shoe Branch
J-L----U ~ Bell oulh Branch
ENDV1EW
93
92
91
42
DW154 Specificatiol for Plastics Ductwork
STANDARD OMPONENT DRAWINGS - CIRCULAR
FIG
94
DRAW G
I
~ 30deg 090deg
Breeches Piece
DETAILS
95 amp-----~ Blank End
~-----p Multi-Leaf Damper Can be piggolcd or fianged opposed or parallel blade
Alternative controls areshyri=-+- L-T~
I
---
LT~
I r- -
-+1
J HO Hand96
bMD Molori cd
PD Pneumatic
tl-shy bull
Single Bladed Damper 97 ~ saD
on-Return Damper Vertical application only 98 m~D
43
DW154 Sf1tcificatioll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG
99
100
101
102
DRAWING
$ I-
2hr
1 4hr
SD
~v I I
CO TINENTAL COWL
DETAILS
Iris Damper
Fi reS moke Dam persSleeves
2hr Ratillg
With installation frame
4br Rating
Smoke damper
Intumescent Sleeve
Access Openings
Access panel - removable
Access door shy hinged
fnspection cover
Discharge Continental Cowl
44
DW154 Sp(Cii(ltJll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
DRAWINGltIC DETAns
-
I
I
~
I I I High Velocity Discharge Terminal 103 I
I
I I
J I I 1 ~--
Offset Stack Discbarge Terminal 104 1
~ I e --(-
I
N
I
I
I~
I I Vertical Oischarge with Weather Cowl 105 I
--1--1 I
I
GAPI I
RTl AL DISC) lARGE WITH W ATIIER COWL
45
DW154 SpecUicatoll for Plastics Ductwork
STANDARD COMPONE T DRAWINGS - PLA TEQUIPMENTIMISCELLANEOU
FIG DRAWING DETAILS
106 ~~~ Rectangular Attenuator
107 ~- Circular Attenuator
108
~ Beod Attenuator
109 J ~(f) Heating Coil
110 J ftte Cooling Coil
III Jc[ Electric Heating Coil
112 X F
Humidifier
113 [H XX Axial Fan
114 ~fB1famp Noo-standard Ductwork Cross hntchillg (of any separate type) indicates by reference to a key any non DVil54 ductwork system
115 2llIIIIJIIIIIll Flexible Ductwork
46
DW154 SJeCUicll(iol1 for Plastics Ductwork
TABLE 12 - STANDARD ABBREVIAT ONS
ABBREVIATION FLL
AD Acces Door
AFF Axial Flow Fan
AHU Air Handling nit
All Aluminium
AP Acess Panel
AT Attenuator
AV Air enninal Unit
BE 81ank nd
BQ Blast ate Damper
CC Cooling Coil
CF Centrifugal Fan
CTA Cross alk Attenuator
CVU Constant Volume Unit
DP Drain Point
EEC Electric Heating Coil
El Expansion Joint
FAl Fresh Air Inlet
FA From Above
FB From Belo
fBPP Fabric Backed Polypropyl-ne Sheet
Flexle Flexible Connection
lexfD Flexible Du t
C False Ceiling CO an oil Unit
fD Fire Damper
FFL Finished Floor Level
FJ Flanged Joint
FOAM Rigid Polyurethane Self xtinguishing Foam
FOB Flat on Bottom
FOT Flat on Top
GAM Galvanised after ManufacttrJc
GRP Glass Reinforced Plastic
GSS Galvanised Sheet Steel
HC Heating oil
HD and controlled Damper
HH Hand Hole
HL High Level
HVD High Velocity Discharge
IC Inspection Cover
ID lri Damper
IFS Intumescent Fircleevc
47
DW154 Specification for Plastics Ductwork
TABLE 12 - STANDAR ABBREVIATION CONTINUED
ABBREVIATION
IU
L
tv1D
MS
NRD NTS
OBO
OE
PHD
PD
PP
PP
PRD
PVC
RFC
RSC
R
SBO
SO
S1 TST
SSL
TA
TB
TO TJ
TP
TV
TV
OS
UPVC
S
V
VAV
50 RSA
FULL
Induction Unit
Low Level
Motor controlled Damper
Mjld Steel
on Return Damper
at to cale
Opposed Blade Damper
Open End
Parallel Blade Damper
Pneumatic controlled Damper
Polypropylene
Self xtinguishing Polypropylene
Pressure Relief Damper
Polyvinyl Chloride
Rolled Form Chamlel
Rolled Steel Channel
R fUnit
Singl Blade Damper
Smoke Damper
Slip Joint
Stainl t el
tructural Slab Level
To Ab vc
To Blow
Top Down (In Direction of Flow)
Telescopic Joint
Test Point
TU111iog Vane
Top Up (In Direction of Flo )
Voles Otherwise Stated
Unpl3sticisecl Polyvinyl Chloride
Underside
Ultra Violet Light
Variable Air Volume
Rolled Steel Angle (Vith Size)
48
DW154 SJeriiflllioll for Plastics Ductwork
A2 DUCT PRESSUREAPPE DXA Ductwork con truct d to DWIl54 will bebullbullbullbullbullbullbullbullbullbullbullbullbullbull
Air Leakage From Ductwork To be read in conjunction with DW143 A practical guide to Ductwork Leakage Testing
CAUTION As highlighted ill both this docul1lenr and DW14 I lot ellough emphasis can be placed 01 the fact that except for high pressure class C the much more stringent ductwork constructional standard brolght about b the general acceptance of DW154 have irtlally negated the requirement for leakage-testing It is essential lO realise lhat except where it is mandatory this doclllllelll is nOl an endors ~lIlent of the rourine testing of ducts bllt purely a guide to outline the procedures for cononnity with the air leakage limits ill Table l Where the specified methods of assembly and
A3sealing of dlcls are u ed a vi ual inspection wil ordinarily sl~fll e for ver(iatioll of a well engineered and a ceptahfy airtight COl1strucrioll WHERE NOT MANDATORY DUCT LEAKAGE TESTING IS GENERALLY AN UNJUSTIFIED AND SUBSTANTIAL EXPENSE
A1 INTRODUCTION L akage from ducted air distribution systems is an Lmportant consideration in the design and operation of ventilatjon and air conditioning middotystems A ductviork t)ystem tbat ba limited air leakag within defiucd limits wiH cnsUft
that tile design characteristics of the sytem can be maintained It wilJ also ensure that energy and operatLonal cosb are maintained at optimum levels DucLwork constlucted and Ulstalled in accordance with DW154 should minimise a level of air leakage that it) appropriate to tll operating static air pre sur in tile system
A4However it is recouuised that tbe environment in wtJich middotystems are installed is not always conducive to achieving a predictable level of quality in term of system ajr leakage and it is therefore accepted that designer may sometimes require tlle ystem to be tested in part or in total It should be ecogni ed that the testing of duct systems add a ignificant cost to the installation and incur some extra tjm within the programme (Se 47 and 64 re mandatory te-sting)
manufactured to a structural standard that is compatible with the system operating pressure There are three classes of duct con truction to eorre pond with the three pre ure clas meations Class A Lo pressure ducts suita le for a maximum positive operating pressure of 500 Pascal and a maximum negative pressure of -500 Pascals Class B IVledium pressure ductmiddot suitable for a rnaxilnuJJl positive operafjn o pressure of 1000 Pascals and a maxllnum negative pre sure of -750 Pa cal Class C High pre sure ducts suitable for a maximum po ilive operating pressur of 2000 Pa cals and a maximum negativ pres ur of -750 Paltcals
LEAKAGE FROM DUCTWORK Leakao-e front pia tic air ducts occur at the joint~ and is therefore proportional to the total surface area orthe du twork in th system Tb level of leakage i imilarly related to tIle air pres ure in th du t system and whilst there LS n precis formula for calculating the level of air los it i generally accepted that leakage will increase in proportjon to pressure to rbe pOvver of 065 The effect of air leakage from high pressure velocit ductwork is critical tn terms of system perfomlan dege energy consumption and the risk of high frequency noise as ociated with leakage These problems are le critical with medium pressure 10 ity systems but should be con idered Low pres mevelocity ducts present the lowe~t
ri k in tenn of tbe effect of leakage on the operation of the s stern
SYSTEM LEAKAGE LOSS As there i no di ct relatLonship between th volume of air conv yed and the surface area f the ductwork sy tern required to match the building configuratmn it is difficult to express air leakage a a percentage of total air volume Similarly the operating pressure will vary throughollt lh 3 system and a leakage is related to pre me the calculations ar comple However it is generally ac epted tbat in typical good quaJjty systems the leakage from
49
DW154 Specificatioll for Plastics Ductwork
each class of duct llnd r operating condition will be io the region of CIa S A low pressure 6 Clas B medium pres un 3 Clas C high pressure 2
A5 SPECIFYING AIR LEAKAGE TESTING Re peeting both the co -t and programme implications a sociated with te ling du 1 for leakage the designer may for example indicate that a particular system is te ted as follow
a) High pressure ducts - all tested b) Medium pr ssure duets - 10 of the
ductwork shall be s eet d at random and tested
c) Low pre sure - unte ed In any case where a random te t i elected for medium pre sure ductmiddot the followin c1au~e is suggested for inclusion by the de ign r
The designer hall elect at random a maxirnwlI of 10 of the dUCl system to bt tested for air leakage The duct hall be tested af the pressure recommended in Table J3 for the assifi atiol for the ectiol1 of the ductwork that is to be tested The tests shall be carried Ollt as the work proceeds and prior to the application of thermal insulation In the event of test failure of the randomlY selected section the designer shall have The right to select two La1her e tiolls at random for resting Where succes ive failures are identified there shall be a Tight to require rhl COl11raCWr 10 apply remedial attention to the complete ductwork system Th contractor shall provide documented eviden e of the calculalions used to arrive (1
the allowable 10 I for the section to be tested and the client or his agent shall willess and sign the results of the test
able 13 Air leakage rates
Maximum leakage of duct work Static
prcssUft Low-pressure edium-prc-sure I Iigh-prebull me diJfercntial Class A Class B Class C
1 2 J 4 Pa Litres per second per quare metre of surface area 100 054 018 ZOO 084 028 300 110 037 400 132 044 500 153 051 600 058 019 700 064 021 800 069 023 900 075 025
1000 080 027 1100 1200 1300 1400 1500
029 030 032 033 035
1600 1700 1800 1900 2000
036 038 039 040 042
Note Recommend d mean test presures are highlighted iD bold type with the actual selection being left to tll test operator
50
DW154 Sfeeiieaioll for Plastics Ductwork
A9
A10
and air leakage classification for the y em under test
DESIGNERS CALCULATIONS The designer can middotaJculate with reasonable accuracy the predicted total loss from a ystem by
a) Calculating the operatin presure in each ection of the sy tern
b) Calculating the surface area of the ductwork in each correspondin pre lire s ction
c) Calulating the allowabl~ los at the operating pressure for each ection of the system (see table 13 for allowable leakage figures)
VARIABLE PRESSUR S IN SYSTEMS De igner can achieve significant co t saving by matchina operating pressures throughout the system to constmctional standard and appropriate air leakage testing eO the practice of specifying construction tandards for whole duct sy tems based on fan discharge pre sure may incur unnece sary costs on a project For example ome large sy terns ould well be classiC ed for I akage limits as follows
Plant room risers CJas C Main floor distriblltJou CIa B Low pre sure outlets Cla A
A6 SPECIAL CASES There may be ~itLlations on a project where circumstance dictate thal pecial consideration be given to containing air loss s eg a long mn of duclwork may incur a di -proportjonate level of air 10 s In ca es such as thi example the designer can specify an improved tandard of airtighmess ie 80 of alJo~able 10 s for la B Ju ts The designer sbould not specif a CIa C t sI at CIa s C pressure for a CIa s B ducl
A7 SUGG S ED RANGE OF TES ING
A8 TESTING OF PLANT ITEMS Items of inline pJant (eg Fig 106 to 115) will not normaUy be included in an air I akage test The dllctwork contractor may indud such itelllS in tbe te t jf rh quipm ot has a certificate of COnfOlnlity for Ihe pres ure clas
bull High pressure duct bull Medium pre sure ducts bull Low pre sur ducts bull Exposed extract syst ID bull Ceiling void extract
systems bull Secondary ducts from
VAV or fan coil units bull Flexjble duct bull Final connections and
branches to grille and diffusers
100 test See A5 Untested UDt sted
Untested
Untested Untested
Untested
SI
i
DW154 SJecijicafion for Plastics Ductwork
ig 116 Permitted leakage at various pressures
Leakage in litres per second per square metre duct surface area
Vgt
o ltgt 0 ltgt N
ltgt Cgt
0 0 cc
0 0
~
g =
g ~
c 0
J
ltgt 0 I
~ ] tn
ltgt ltgt
In ol
~ 0 ~ 8 ~
~
c ltgt ltgt
~ CJ
~ ~ ~ ~ 8
0shyij
~ ~ ~ t
ltgt ltgt 00
l
~
~ Q
c C
~ rshy
e ltgt
I 1
I Cgt ltgtv
c Co ~
~~ ~ 10
I
0 Cgt
fJshyq 410 ) 1 ltgt
ltgt N
~ shy ltgt ltgt
~ I 1
c
52
DW154 Specificatio for Plastics Ductwork
Example of a completed test sheet Test No
General
Name of job N~ jC43Pt(r2lef Building Repound ~(~~0
Part 1 - Physical details
a Section of duct work to be tested ~(diffPIfff~el1f3rd Floor
b Drawing Number g91~~ c ssure aSSJ L atlOn V~Jl~IRfYgtg~~lPre Cl T Class C
d Test static pressure -(9 raErq~ ~~~~-~~J~~~ ~~ ~~~~ll
Leakaoe factor 9~-tre3$ecMz I OM REFTOTABLE 13)e b bullbullbullbullbullbullbull
f Surface area of duct under test Q~tJJItetre$ CPROMCALCU TIO BELOW)bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull ampampamp bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull
g ]Vlaxi mum permitted leakage -~ (~i~~0 ~~r~~ ~~~l-~-11~ ~~~Q
Part 2 - Test particulars
a Duct static pressure reading 9QFt~q~ ~ middot~~~1 ~~
b Manufacturer and type of liow measuring d vice (-~~~cJ~Y-9Q7EYg c Range of measurement of now measuring device QtP)OQ~(e~~~0I~~~~1~I~ ~~~~~~W~
d Reading of flm measurin o device pmiddot IFROM RIO)ftscag ~
I (DERlVED [ROM CHART SUPPUED WITH RIG US 0 ud)1e Interpreted air flow leakage rate ~(~~~f~~~ (~l~~~~~~~~~~~~~~~~~I
f Duration ~~~~~norn~allY l~ lnil1Ut~~d~~~ it1~ W~ Date of test ~(lITled ut by Wltll s ed by ~ ~
(~lJ MIJLrr) (Si~rrfltJUYJ
Printed Name 1~g0f~ Printed Name ~~Y~9~ and Company 7jl~~~~~( UJd CompanY AB COII$Itallt8
Width and depth or diameter
Periphery ength Area
millimetreS millimetres metre qL1are metre
800 x 750 3100 1755 5440
600 x 650 2500 557 1193
300 x 300 1200 120 144
305 din 958 700 670
250 dia 785 450 353
TOTAL 8000
53
DW154 Specijilarion for Plastics Ductwork
pA XB
Guida ce No es For he ransport Handling and
Storage of uctwork
avoid damage to adjacent duct panels In somc ca es particularly on con acts calling f r repetitive sizes the use of timber jigs and spacers may be justified Where reduced bulk and greater protection are major factor such as consignments for export transporting ductwork in L shape sections may justify the increa ed ite as embly co ts
It is recommended that before a contract is finalised that consideration is given to the subject of site acces material handling and storage as tbcy havgt a strong influence on the cost efficiency of the overall activity of ductwOlk installation
B3 Handling To minilnise th risk of damage duct sections should be clearly identified and deliveries to site should be closely linked to the installation programme so as to avoid accumulation of
B1 Storage and Handling of Ra Material Material should be stored in suitably designed racking out of direct unJight Where possible the e racks should be metal to earth Edges of cut she t may be harp and protective gloves are advised Wearing teel toe-capped boots is recommended Most pIa tic sheet is manufactured with smootb mfaces andor is suppLied with protective coating Care must be taken to prevent accidental lippag of stacked materials Beiuoshy good electrical insulators the movement of stock unless earthed will allow the build up of stati All stock shapes are chemically stable at normal temperature Whil t some raw materials used in their manufacture may themselves pre ent a toxic hazard once incorporated into the lOck bape they no long r constitute such a hazard and no dermatitic bazard are known nor are any
unfiJied ductwork and minimise double handling It is important to recognise that ductwork panels joint and corners arc susceptible to damage and care must be taken wheu band ling such material through a site During handling individual item of duct work may be liable to light cross sectional deformation until thev become an integral pan of a completed ductwork system Whilst this may temporarily detract from its intended appearance thi deformation will not have any detrimental effect on the functionality of the finally a semblecl system Installation of duct work and asociated plant items ill illevitably involve manual handUng The responsibi Iiry of employers and employees to a ses the risk of personal injury during mallual handling operations is et out in the HS E publication L23 Guidance on Manual Handling Regulations 1992
environmental problems expected 84 Site storage
B2 fransport Large capacity vehicles with high-sided open or closed-top bodies are tlle mo t suitable for the transport of dllctwork Careful consideration should be given to the
Adequate floor space IDust be provided within tbe building for the site storage of ductvork Such storage shalt make due allowance for thc stOf(ne of ductwork in stacks such that access ~ egt
between them is of sufficient width to pennil the removal of item without interference to
unloading of transport on sit a not all siJes b n fit from the material handlino- and access facilities that exi [ in a manufacturing workshop such as crane- fork-lifts or loading bay Site handJiog facilities along with
adjoining sta ks Ductvork components should be positioned so a to avoid crushing Ductwork of small panel size may be stored horizontally however care should be exercised to ensure that tack sizes are limited 10 within
ehicular acce s restrictions may itilluence the type and ize of transport to be uWised
engtlls of ductwork should be positioned 0
the tmctural strength of the duct sections to prevent distortion of the lower sections within the stack
as to avoid crushing Lengths Witll projections such as branches and bends i1anges girths damper quadrauL should be loaded so as to
54
DW154 S1tciic(ltioll for Plastics Ductwork
85 Internal cleanliness of new ductwork The site storage of ductwork introduces the important cODsideration of maintaining the internal cleanliness of the ductwork R feren e should be made to HVCA documentshybull DWffM2 Guide to Good Practice - internal
Cleanliness of New Ductwork Installations If the above conditioDs can not be satisfied consideration should be given by tJle designer to amending the specification to include for Po t Installation Cleaning as covered by tJ1C HVCA documentshybull TRJ17 Guide to Good Practic - Cleanliness
of Ventilation Systems
APPE DIXC
Fi e Retardant inishes C1 Improvement in the fire retardancy of plastic
ducts can be achieved to varying degrees and is wholly dependent llPOll the surface coating laminating resin selected and construction specification adopted In some instances smoke emission is coILSidered equaUy with other speci fication requirernen ts of the materials resistance to ignition and bumjng It is therefore important for design rs to establ ish the clients and officers detailed requirements and not rely on a tbird party interpretation of fire resisting or fire retardant Where possible the specification should refer dir etly to compliance with a British or European Standard identifying the specific sections applicable There are various types of resin and mat rcLnforcements that can achieve a Class 1 surface spread of flame ratin o when tested according to BS476 Part 7 (1987) This test puts materials illto Class I - 4 in descending order of perfoDllance according to the rat and extent of flame spread over their surfac under standard beating conditions Materials should also be tested for flre propagarion to BS476 Part 6 (1989) Tbi tesr measures the amount and rate of heat evolved by the material when subjected to standard heating
conditions Test results are given as an index of Perfonnance (i) whicb is based on three sub indices (iJ (i1) (h) The higher the value of the Index of Performance (i) the greater is the material s contribution to fire growth The higher the value of the sub-index 0) rhe greater the ease of ignition aod flame spread The highest product performance classification as defined in Approved Document B of the Building Regulations is Class O This is acLlieved if a material surface of a composite ploduct i~ either a) composed throughout of materials of
limited combustibility or b) a Class I material which has a tlre
propagation index (i) of not more than 12 and sub-index (i l ) of nor more than 6
01 J Class 0 is not a cla$sif1cation identified in any British Standard test
There are resin system reported to be classified to Class O when tested to BS476 Pcl1S 6 and 7 however designers need to ensure that such sysrems can be applied to their proposed design In propriety resinmat system available the fabrication techniques and COITect application are critical to the integrity of the reinforcing and clas ificatiol1 For example in some systems the u e of a non-fire retardant gelcont on a fire retardant substrate would reduce the classification For further information see HVCA publication DW144 Appendix D
55
DW154 SplCijiClIliol1 for Plastics Ductwork
x Guidance otes For nspectmiddoton Servicing a d
Clean-ng Access Openings
D1 GE ERAL This appendix highlight in ummary fOI111
the acce considerations that hould be made by the design r iD terms of inspection servicing and cleaning Having considered the seop and the design of the dUCI work system relative to the guidelines outlined below the designer should clearly indicate which levels of acces should be incorporated into the manufacture of a new duct work system (See Table 14 and Note I b low it
D2 DESIGN CONSIDERATIONS
D21 In ptction and servicing requireshyments are set out in Section 15 of Lhis specification
D22 Cleaning requirements are set out in the HVCA pubUcation TRl7 Guide to Good Practice Clean Lines of Ventilation Systems and the guide tates The precise location ize and
type of access would be dependent on the type of ductwork cleaning inspection and te ting metbods to b adopted Care protection and standards of cleanliness prior LO cOlllmisionin o
are set out in th AV A publication DWITM2 Guide to Good Practice Internal Cleanliness of New Ductwork Installations and th guide state Wh re specific limits of cleanliness are required ductwork sball be cleaned after installation by a spcialist cleaning contractor It will b in the interests of tht desioner botb financially and practically to cunsider employing a specialist c1eauing contractor at tbe
outset of a contract to internally clean newly installed ductwork prior to bandover This approach would reali e the following benefit shyi) Tb actual numb r of cleaning
access panels could be detennined to suit the method of cleaning to be adopted (This may be 1 s than the maximum requiremen listed under Lev 13 of Table 14)
ii) Clear directions could b given to the ductwork contractor as to tJle size and location of cleaning access panels that are required to be fitted during the mauushyfaclunng pro s
iii) The specialist cleaning operation prior to commi ioning vould enable the cleaning contractor to verify the practical acee requirement for the future cleaning operation associated -vitb a regular maintenance programme
iv) A specialist cleaning operation prior to commissioning would allow the designer to omit from the speeilicatiolJ the DWrrM2 requirem nt for factory sealing protection wipe downs and capping-off
v) Specialist Ieall ill 0 to the measurable standard defin d in TR17 will allow an objective definition of cleanline to be achieved
Car ful consideration must be gIven by the designer to the practl aJ problems associated witb the manufacture and fitting of suitably si Led access panel on small cross section duct and on the circular faces of rouod and flat oval ducts in particular
D23 Special con ideration must be given by the de igner to the practical problems associated with gaining personnel access to heavily congested ceiling areas and multi-la red du twork systems This approach would avoid
56
DW154 Spfciication for Plastics Ductwork
the possibility of access panels being D3 ACCESS 0 IN-LINE EQUIPMENT incorporated into a ductwork system at the This appendix unly covers acc il1spection manufacturing stage that were later found in through the ductwork body adjacent to an item practice to be inaccessible for either ervicing of in-line equipment and not openings in the or cleaning activities equipment itself
able 14 Acce requirements for inspection servicing and cleaning
HVCA PUBLICATIO REFE NeE (uidtgt 10 Gund Prartict
Adjace t OW144 Cleanliness orVcnlillltio S~lcr~ fRjJ7
in-line LeyeJ 1 Level 2 Level 3 ite sequipment pcdionSen lcin~ Section d C1eaniJl( SUn(O)lnspc lion Palle ltk~m_n
2011 (minimum OiL Jubje-ct to duct ~zel (ft~ -Panels
Control Da pcrs One (inspection) 203 One 300 mm x 200 mm Both sid Fire Dampers One (sCTjdJl~) 20211 One 300 0101 x 200 mm One side HeatingCooling Coils One (inspedion) 20213 One 300 mm x 200 mm (lIpstream) Both sides Attenuators (rectangular) None required One 300 mm x 200 mm (downstream) Both sides Attenuators (circular) one retluired One 300 mm x 200 mm (downstream) One side Filter Sections One (inspection) 20212 one required Uoth sides Air Turn Vanes None requjred None required Both sides Changes of Direction None required one required One side In-Duct FansDevices One (inspection) 20213 None required Both sides l
1 In the absence of any indication by the designer only Level ) access will be jncorporated into a new ductwork system
2 Tbe panel izes associated with Lev lis I and 3 acee s ar e middottablished by reference to Section 20 of DW144 and Section 2 ofTRll7 respectively
57
DW154 Speclfifatio for Plastics Ductwork
pA XE
B-bliography Included in this Bibliography are technical pUblications which may be of interest (0 ductwork designers fabricators and erectors and to tho e in the heating ventilatlng air conditioning industries generally nquiric should be made of the relevant organisation at the address quoted Since its publication other addresse contained within 0V154 mav have changed and some pubJicalions may have been superseded
HEATING AND VENTILATING CONTRACTORS ASSOCIATION
4 Palace Court London W2 4JG Telephone 020-7229 2488 Fax 020-7727 9268
Orders fo FlY A Publications Old Matlsion House Eamont Bridge Penrith Cumbria CA 10 2BX (Telephone 01768 864771 Fax 01768 86718) Email hvcapoblicationshvwelfarecouk DWn 44 pe ilicatiun for sheet mctal duclwork (Iow- mediulllshy
and high-pressure) 1998) DWIl4 A practical guide to dUGI ork I akage te ting
(revised 2000) DWII54 Specification for plastic~ duct rk DW171 Guide to good Practice for kitchen venlibtion system DW191 Guide to good pracuce glass fibre ductwoJk DwrrMI Acceptance cheme for new products - Redangolar cro
joint classification Guide to good pra tice - Internal cleanliness of new ductwork installations Guide to good practice for the design for the Installation of lire and smoke uampers
J 1Other puhlications
HampV safely guide 5th edition JS2 Tool box talks JS5 Weldlng Safety booklet JSI9 afety facts bo klet Fact sheets 1-24 2nd edition JS2J COSHH manual volume 1 Advice on compliance with the
regulations 1521A CO I-rH manual volume 2 Asses mcnt h ets JS23 Ri k management manual TR3 BrazinltT and bronze welding of copper pipework cUld sheet
(I 976) TR5 Welding of carbon steel pipework (1980)
TR6 Guide to Good Practice for Site Pre sure Testing of Pipework (19 0) Guide to good practice cleanliness of ventilation Ylem
CHARTERED IN TITUTlO OF BUILDING SERVICES E G EERS Delta House 222 Balham High Road London SW12 9BS rTelephone 020-8675 5211 Fax 020-8675 5449) CIBSE Guide Volume A Design Data Volume B In tallatiol1 and quipment Data Volume C Reference Data
CommlssioniJIg Codes These Codes eover the preliminary checkS eUing to work and regulation of vanous catcgories 0 plan The Codes give a guide to design implications Series A Air Distnbution Systems Series B Boiler Plant
ri s C Automatic Conlrol ystems Cr1es R Refrigerating Sy terns
Sene iN Water Distribution Systems
Technkal Memonllda TM 4 Design Notes for the Middle East TM bull Design otes for Ductwork TM 13 Minimi iog lhc Risk of egiounaires Disease
Research Reports RROI95 Ventilation system hygiene - A review of published
infomlatioo on lhe occurrence and ffects of Olltamination Rl~02J95 Air-to-air heal rec v ry RR0395 rnfluen e of HV C on smoke detectors
ATlONAL ENI [ERING SPECIFICATION LfMITED Southgatc hamber 3739 Southgate Street Winchester S023 9EH (Telephone 01962 842058 Fax 01962 R(8982) BUfLDING S RVICES RESEARCH AND [ ORMATION ASSOCIATIO Old Bracknell Lane West Bracknell Berkshire RG 12 4AH (Telephone Brackl1eU (01344) 426511 Fax 01344 487 -7 )
Application Guides AGln4 De tglJing Vana~le Volume middotylans for KOOnl
iir Movement AG1I91 Commissioning of V Sylcms in Buildings 11 6194 Fire Dampers
B) 94 cntiJalion or KitcneTls
AG389 The Commls ionin of Air Systems In Buildmgs AH2192 Commissioning of Bern - A ~ode of Practice TN2417 I Fire Dampec il) Ventilating Ducl
BEATING VENTILATING A AIR CONDITION G MA UFACTURERS ASSOCIATIO (HEVAC) HEVAC Henley Road Medmenham Marlow Buck SU 2ER (Telephone 01491 578674 ox 01491 575024 Emoimiddot infofetacouk)
Publicatjons Air Diffusion Guide Guide to Air Handling Unit Leakage Testing Guide to Good Practice Air Handling Unit Real Room Acoustic ~ st Procedure Specification for the ertiiicatioll ofAir Filters Method of Test for Water Rejection PerfOnTlatce of Louvrcs Subjected 1(1
Simulated Rainfall Test Procedure for Acoustic Loo cs Specification 10 Floor GrilJes - Types Performan e and Method ofTest Specification for the Determination of the Collection Efficiency of SilJ1d
Trap Louvre Domestic Mechwlical Vclltllalion Systems with Heal Recovery Fan Application Guid
~an and Ouctwork Installation Guide Guide to Fan Noise and Vibration
pecification of Requirements for JallJral Smoke and Heal Exhausl Ventilators
pecification for Powered Smoke and Heat Exhaust Ventilators
Specification of Requirements for Smoke Curtains Design Gujue of Smoke Ventilation for Single Storey Lodustrilll Building~
Including those with Mezzanine Floor and IIi Racked Storage Warehou es - Issue 3
Guidance for the Design of Smoke entilation YSlem for Covered and Undergrollnd Car Parks - lssue 1
Application of SOloke Control Equipment and Syst m Guid to Good Practice - Isue J
58
DW154 Sp(C~tiifitiol for Plastics Ductwork
BRITISH STANDARDS INSTIT TION Sales Department 101 P ntooviLle Road London NI 9ND (felephone 020-78 1 78801)
CP 413 1973 Ducts for building ervices
SS 476 Fire tes on building matenals and lruc(ure
Part 4 19 4 Non-combustibility lest or materials
Part 6 I Fire propagation lest for materials
Part 7 1993 Surface spread of tlarnJ tesls for materia
Part 20 1987 Fir resistance of elements of construction
Part 21 1987 Fire r sistlUlce of loadbeanng elements of construction
Part 22 1987 Fhe istallceofllon-loadbearing elemcllts ofconsttuclion Part 23 1987 Contribution of componcnts to the fire resistance 0 a
structure
Part 24t987 Fire resi lance of wl1lilation ductl
SS 5588 nan 919 0 Fire Precautions III thc desIgn and OOSlnJ lion of buildings
S 729 1971 Hot dip galvanized oatiugs (or irOIl aod stcel articles
BS 1449 Steel plate sheet and Irip
Pan 11991 Carbon steel plate heel and strip Part 2 1983 Stainless steel plate sheer and strip
and
B middotENJOI49-2 996 BSEN 10149- 1991)
BSEN 10131 1992
BSEN22063 Sprayed metal coarings 1994 Protection of iron and steel by aluminium and zinc against
atmospheric cOlosion Irotectiotl of iron and ste I against corro ion and oxishydation at elevared temperatures
BS 353 1981 Glossary of lerms relnting to thermal insulation
BS ISO 1479 Self-tapplngscrewsandmetallicdri c crew
B -lSO 7049
1994
B 4800 1989 Painl colour for building purposes B 4848 l0 rolled structural steel sections
Part4 1972 Equal and unequal angles BS 5422 1990 Specification for the use of therm illuating matcriulS
SS 5720 1979 ode of practice for mechanical veutilating and air C 11shy
dirionin bull in building
l3S PR 12814-1 Bend resting for plasric welds
SS PR 12814-2 Tensile testing for plastic welds
SS PR 13067 Appro altesting for plastic welds
BS PR EN I 100-] Vi ual in pection ofplaslic welds
SHEET METAL AND AIR CONDITIONING CONTR-CTORS NATIONAL ASSOCIATION INC (SMACNA) Headquarters 420 I Lafayeue Center Drive Chanlilly Virginia 2051-1209
Mailing Address pa Box 221230 Cbantilly Virginilt120 153-1230
Telephone (703) 803-2980 Fax (703) 803-3732
Accepted IJJdustry Pl3Gtice for Industrial Duct Constnlelion 197 ) i-rchitecmral Sheet kwl Manual ([993)
Comractors Guide lor Modification 10 ooslruerion Colllraets 1993 Ducted Eleclric Heat Guide for ir Handling Ssrerns (1994)
En~rgy ollservatioD Guidelines (1984) Energy Recovery Equipment yslClllS (199l
Fibrou GIns Duct onS1ntClion Standards (1992)
Fire Smoke amp Radiation Damper In tall Guide for HVA Syst ms (1992) Guide t leel Stack 1(95)
HVA Air Duct Leakage Test Manual (19 ) HVA COlllmissioning lvlanual (1994)
H A Duct Construction Standards-Metal amp Flexible (1995) Addendum 01 (Nov 1997)
HVA Duct Systems Inspection Guide (1989)
HVA ySlems-Application (1986) nVAC ByternS-DLlct D ign (1990)
HVi Systems-Testing Adjusting amp Balancing (1993)
indoor Air Quality Manual (1993) tcheu quipment Fabrication Guidelmes (1990)
Managers Guide for elding (1993)
Rectangular Industrial Duct Cons1TUction Standards (19 0) Round Industrial Duct oustmction Standards (1977)
Sei mic Restraint Manual (1991) (wl Appendix E 1993) SMACNA Ma le Index ()fTechnical Publications (1995) Tbennoplnstic Duct CPY ) Construction Manual 1994)
DEPARTME OF THE ENVIRO MENT (Publications Centre) H Stationery Oflice 5 Nine Elms Lane London SWS 5DR
MampEJ 011972 Electrical in tallat1011 in buildings ( ew Editiou)
IampE 0319 Healing hot and cold wat r steam and gas losla1lations for buildings
M amp - No4 1970 Central heating and hot and cold ~ ateT in tallations for
dwelling
M amp ENo100 1971 Mechanical ventilation for building~
ASSOCIATION FOR SPECIALIST FIRE PROTECTlO As ociation House 235 Ash Road AJdershot Hampshire GUl2 4DD
Telephone OJ25221322 Fax 0 J252 333901
lublicalioos Fire Ratcd and moke Outlet Ducrwork An Industry Guide t Design and InSlalla lioll
HEALTH AND SAFETY EXEC TIVE Rose Court 2 Southwark Bridge London SEl 9HS Telephone 020-7717 6000
TWJ THE WELD G TlTUTE Abington Hall Abington Cambridge CB16AL Telepbone 0 J223 89162
Publication DatJ Oil w~ldll1g of lhermopla lics
59
DW154 wciiwlioll for Plastics Ductwork
A -=--DIX
Factors
Specific gravity shy pp = 091 approx UPVC = 14 approx
Some miscellaneous conversion factors
To convert
Length Inches to millimetres Feet to metres
Multiply by
2540 03048
To convert
Millimetres to inches Metres to feet
vIultiply by
003937 3281
Area Square inches to square millimetres 6452 Square millimetres to square inches 000155 Square feet to square metres 00929 Square metres to square feet 10764
Volume Cubic feet to cubic metres Cubic feet to litres Gallons (UK) to litres
002832 2831 4546
Cubic metres to cubic feet Litres to cubic feet Litres to gallons (UK)
35315 00353
022
Mass Ounces to grams Pounds to kiJograms Tons to tonnes
2835 04536
1016
Grams to ounces Kilograms to pounds Tonnes to tons
003527 2205
09842
Volume flow Cubic feet per minute to cubic Cubic metres per second to cubic
metres per second 0000472 feet per minute 2119 Cubic feet per mIDute to litres Litres per second to cubic feet
per second 04719 per minute 2119
Motion Feet per minute to metres per second 000508 Metres per second to feet per minute 197
Pressure Inches water gauge to millibars 2491 Inches wateJ- gauge to pascals (Pa) 2491 I Pa = I ewton per square metre = 10-2 millibars
60
Heating and Ventilating Contractors Association Esca House 34 Palace Court London W2 4JG
Tel 020 7313 4900
e-mail contact Itvcaorguk web site wwwhvcaorguk
Fax 020 7727 9268
DW154 Sedicalirm for Plastics Ductwork
adju table through a nominal 90deg angle simultaneously by intershyconnected linkage or gears connected to a quadrant or similar operating mecbanism Where automatic control of a damper is required a spindle shall be extended to enable a powered achlator to be mounted
There is no restriction on the size of duct in which multi-blade dampers or damper assemblie may be u ed Where dampers are required for blade lengths in excess of 750 mm the blades should be suitably reinforced or supponed 0
individual damper blade should exceed 200 mm in width
1623 Iris dampers Lris dampers shall consist of a nUlllber of radialty interconnected blades which open or close within a casing with duct COlll1cctions The blade shall be simultaneously adjusted by a quadrant or similar operating mechanism
Iris dampers shall be installed as specified by the manufacturers operating and installation instructions where the product is unidirectional with regard to airflow
lris dampers are available for circular ducts only in diameters up to 250 mm (it should be noted that the damper casin i appro)(imately twice the diameter of the duct)
1624 Backdraught dampers Air pressure operated uni-directional rectangular (single or multi-blade) with adapters if fitted to circular ducts
1625 Slide and blast gate dampers A damper [lsed as a shut off facility with an externaJ Lide bousing allowing the blade configuration to be fuJly inserted to fully extended for maxiDlUlll air flow
163 Construction
1631 Materials All products shall be protected against cOHosion as necessary and supplied in a fully finished condition as specified by the designer
1632 Dampers used in low and medium pressure systems The following recommendations apply to dampers forming an integral part of ducrwork with pressure classifications A and B air leakage limits
The dampers shaH be constructed to minimise distortion and prevent jammin in operation Th blade shall be sufficiently rigid to minimise movement when in the locked pOSitiOLl
The blades shall be securely fixed to the operating mechanism All balancing dampers shall have a locking device located on the outsid of the case and shall giv clear indication of the actlwl blad position All penetrations of the duct shall be fitted with suitable seals where necessary
1633 Dampers used in high pressure systems Regulatino- dampers used in duc[work sy tems to pressure cJassification C shall meet tbe construction requireshyments specified in 1631 and 1632 with operating mechanisms out of the air-stream
1634 Proprietary types of damper The use of any specific type of proprietary damper shall be confirmed by the designer In all cases proprietary dampers shall meet the relevant requirements of thi specification
1635 Damper casings Duct damper casings hall be constructed to meet th mllllmum
23
DW154 SpeciJimlioll for Plastics Ductwork
leakage Iim its sp cified for th c1uctwork ystem to which tbey are installed
In order to apply the square metre leakage calculatio as detailed in DW143 A Practical Guide to Ductwork Leakage Testing the reference casing area ball be taken as the perimeter ize of lh damper IDultipli d by the equi alent length of Imetr eg an 800 mm x 400 mm duct damper hall have a surface area for casillg leakag p donnan calculated as follow (2 x 08) + (2 x 04 x I
=24m2 casing area
Other pelforlllance ancl rating test methods for damp f and valves are specified in ISO 5129 and BSIE 1751 and are referenced belm a) Leakage past a closed damper
alve BSIE 1751 b) low ratepre sure requirement
characteri t cs BSIE 1751 c) Operational torque le ring
BSEN 1751 cl) Thermal transfer testing
BSIEN 17 I e) Reg nerated sound power levels
ISO 5129
164 Installation Dampers shall be imaalled in accordance will) any re Ievant ISO EN or British Standard 10 aJ bUT lcling regulation and national code of practice as well as the manufacturers recommendations
17 FIRE DAMPERS AND INT MESCENT SLEEVES
171 General Damper or sleeves arc requiTed on duct y~telll where the designer has -tjpulated the
duct wiU penetrate a fire compartment in the majority of application tbermopla ti ductwork is ugtecl where contamlDated corro ive or otherwise exceptional fumes are concerned it is preferable to use tire damp r which are externalJy mounted ie of the intmnescent operated crush typ
24
72 Fit-e rating The damper assembly should have a fUT
resi tance ratin o equal to that of the fir ban-jer it penetrate and ball be fire tested and rated to the timetemperature curv of B 476 Part 20 and 22
173 Intumescent sleeve At the time of writing this specification qualified test results were available for rectangular dampers and circular dampers up to 55 mm diamet r Manufacture have indicated that they are able t provide speci fications for other size and diameters This infonnation should be confirmed b th de igner Various type are available includino
tho e incorporating ruechanical closing plate and those operated anI by expanded iJllUme c nt media
In all ca es fire damp rs and intnmeBcen leeves shall be supplied and in taUed in
accordance with the manufacturer iJlStructioos and COSHH a essm nt
174 Other types Fire dampers of mious types are availabl for specific purpose~ ee HVCA publication DW144 The de igner should )lot (hat materials for con lt1Jction bould be uitablc for the par1icular application
ALL C SES FIRE DAMPERS AND fNT MESCENT SL _VES SHALL HE S PPLTED AND INSTALLED IN A ORDA CE WITH Tf--IE MANUshyPACTURERS STRUCTTONS AND COSHH ASSESSMENT
18 FLEXIBLEEXPANSION dOINT CONNECTIONS
181 General ploperties Tbe material u ed for flexibleexpan ion iojnt~
mu t meet the design r requirements for temperature air pressllrelfe resistance applicable to pl astic duct sy tem vibration and noi e br akout when incorporated into a jointconnection and shall comply ith lh standard of air-tigbtne specifi cl for the duct work sy tem of which it fOlms part (See Figs 23 24 5 26 27 amp 28 for typical con truclion clelai Is
DW154 SJecilimtol for Plastics Ductwork
Expansion joints
Fig23 Moulded bellows type (rectangular and circular)
Fig24
~F aiblc sleeve
__ liding sleeve
~~~~
Sleeve type (circufar)
Fig 25
AIRFLO
COnlinuou~
weld~
Flexible Iceve
PV A HOWN pp SE BACKING FLATS AS FIG 2
Sliding lee c Co1linuou
weld
Flanged sleeve (rectangular and circular)
25
DW154 Specificatiol for Plastics Ductwork
Flexible con ections
Fig 26 Flexible sleeve with clips (UPVC and PP)
--__ Flexible I eve
I
I
I CODn clioD to plant ~
Band clip
Fig27 Welded flexible sleeve (UPVC only)
Plastic)sed PVC slceve ~-- onll11uo1sly welded
onrreclion to planl ~
Fig28 Flanged flexible connection (UPVC and P )
t sp dally moulded flexible flanged connCClitlll
boil
C)nneclion to plant ~
26
DW154 Specificotiol for Plastics Ductwork
182 LOClt1tion Flexible joint are typicltllly lIsed at building expansion joint and fan inletsoutlets Any others required should be indicated on the de ign drawings Care should be taken to maintain alignment across jointsconnections
183 Length Flexible Jomts shall be kept as short as pra middottieable above a minimum eft ctive length of SO mm In no ca e shall a flexible joint exceed 250 mm in lengtb
184 Connections to rectang a ducts With flanged rectangular connections Ule tlexible material shall be held in pLace with flat pIa tic strip of not less U1an 6 mm thick ltlttached to the flanges using uitabJe fixings The more heavy weight type of fleAible mateLial may also be obtained formed into a channel ection with corners fitted to give a neat air tight j int For pigot connections the Be ible material shall b held in place with flat pIa tic trips n t less than 6 mm thick
t 85 Connections to circular ducts With tlanged circular connections the flexibl material shall be held in place with flat plastic backing strips or proprietary clip bands with screw or toggle fast ners
186 Welded flexible connections (Rectangular and Circular) Where the parent and llexibl material are from imilar ba ed products they can be joined to the duct u ing the welding method described in Section 823
19 PROTECT VE FINISHES
191 nles otherwise stated all ductwork shall be mallllfactured in mat fial as pecified in tbis specification Any special coatingpaint fmishes to be provid d by the duct work contractor sball be advisd by th de igner
20 CONNECTIONS TO BUILDING OPENINGS
201 Fanning and finishing building op nings are not the repoJlsibjlity of the duftw( rk contractor and the note that follow are for guidance purpo e only
2011 Openings in brick block or concrete walls shall have inset frames to provide a suitable means of fixing grille louver masking flanges or the tlanged ends of ductwork The illset frames shall be conslnlcted to maintain the structural int grity of the wlll and where applicable cavities shall be suitably lined
2012 Openin s in dry linino partItIons shall have inset frames a 2011
2013 Openjngs in cladding walls and roofs shall have flaoged leevesframes to provide a suitable means of fixing a 2011
2014 Horizontal and vertical opening xposed to oLltside atmo phere hall
be provided with a suitable weathering fini h at the external face especially where profiled cladding is used
2015 Timber framed op nings are not permitted In fj re compart ment barriers
202 Ductwork connections to building openings hall have a flange of suitable profile to permit practical fixing to the openillg frame In selecting the profile consideration shall be given to Tabl~s 2 and 10 in this specitication relating to duct ize and rating Gasket strip or sealant shall be ltlpplied between the tJaoge and building op ning frame
21 DISCHARGEEXHAUST TERMINAL
21 Tbese shall be vertical open ended and designed to meet and comply with current r gularions on contaminated flue The designer hall ensure that the de ign and perf rmance i suitable for its intended purpose Examples of some typical terminal designs are SbOiD in Figbull 102 10 bull 104 amp 105
27
DW154 SpedjimioTl for Plastics Ductwork
22 THERMAL INSULATION
221 The provision and application of thermal insulation to ductwork is not the responsibility of the ductwork contractor
222 Where ductwork is required to be preshyinsulated the specification should be agreed with tbe designer
223 Where the temperature of the air within the duct promotes condensation on the exterior surface of the duct and cause moisture penetration througb the thermal insulation vapour scaling may be required and in this case the most important requirement is to limit penetration of the seal
The extent of any vapour sealing of ductwork thermal insulation and the support method to be u ed must be clearly pecitled in advance by the designer
224 For detailed information on the thermal insulation of ductwork reference should be made to BS 5422 1990 which covers the specification for thermal insulation materials on pipes ductwork and equipment (in the temperature range -40degC to +700degC) and BS 5970 1992 which is a Code of Practic for Thermal Insulation of Pipework and Equipment (in the temperature range -lOOdegC to +870degC)
23 FIRE RETARDANT FINISHES ON PLAST C DUCTWORK
231 The designer should note tbat ductwork constructed to DW154 has no teted fire rating or information see Appendix C
24 REINFORCEMENT OF DUCTS WITH GRP LAMINATE
241 General Where ductwork is required in larg T izes than are covered by Tables 2 4 6 amp 7 or with the increased strength sometimes necessary for industrial use external reinforcement is normally pwvided by applicatioD of glass fibreresin laminate
GRP systems will bond satisfactorily with standard UPVC sheet but for pp it is
nece sary to use a specially prepared sheet with a glass fabric backing incorporated dOling manufactllfe
The detailed techniques of fabrication using GRP are outside the scope of this speci lcation but the following notes are offered for guidance of ductwork fabricators
242 Materials
2421 Quality The laminate is made up of polyester resin complying with BS 3532 and glass fibre complying with BS 3496 or BS 3749 The nominal ratio of resin to glass fibre should be 7030 by weight
2422 Minimum properties The laminate shall comply with the followiog mini mum pbysical properties
Tensile strength - 70 MNm Tensile modulus - 7 Gl m Flexural strength - 140 M Im Bond strength (hetween laminate and substrate Not less than 7MNm Bmcol hardnes Not le s than manufacturers specification
The GRP reinforcement educe the expansion of the parent material but the resultant stre ses arc well within rhe strength of the bond However the Iinear thermal expansion curve shown in Figs 34 amp 35 will serve as a guide
Surface resistivity electrkal propcltles and acoustical propertie are similar to the relevanl unreinforced materials The fire retarding properties of GRP may be improved by the use of specialisl laminating resin
2423 Forms available GRP Laminate should be built up from the separate materials ie resin aod glass fibre in the form of chopped
I strand mat or spray ravings
28
DW154 Spcification for Plastics Ductwork
2424 Workshop conditions Polyester resuls are sensItIve to lmperature and the workshop hould b maintained at a temperature of herween 20deg and 25degC HiOh relative humidities and damp onditions should be avoided A good rate of air change must be pro icled pJeferably by m chanical ventilation
2425 Storage of materials Resin and urin o agents shouJd be stored in dark cool condirions away from the working area and in confonnit with statutor requireshyments for tJle middottorage of flarmnable liquid Because of Ule Limited torage lif of the unmixed resin and curing a eot mal lials ~hould be ch eked before use to enLlfe that they are within the manufacturer pe ified sh If life (usually ix month from the dm of manufacrure)
Glass fi re should be stored separately und r clean dry conditions
243 Surface preparafon
2431 UPVC To achieve the specified bond strengtll the urface to which the GRP is applied mut first be thoroughly cleaned and then etched either by mechanical means or by the use of a suitable solvent
2432 pp with glass fabric backing To achieve the specified bond middottrength the fabric backing must be thoroughly impregnated Witll resin
244 Mixing the materials for use The re in 1 a three part mix compri lng base I sin hardener and accelerator The manufactur rs pecj[ied proportions are critical and th llUxmg sequenc pecified must be meticulously foUowed
The resin has a very limited life after mixing and before u e It is dependent on the characteri tics and bulk of th resin the alllount of hardener the degree and method of acceleration and the workshop onditions
245 Methods of application
2451 General The mixed resin may be applied by hand or b pray c1epoition The operation must b completed within the gel time of th y tern and tbe laminat fully cOI1olidated to achi v the phy ieal properties pecified
2452 Hand lay-up The duct surface i coated by hand with resin Llsing a brush and a mar of gla fibp orked in until full consolidation achieved Th proc is repeated untiJ th requird thicknes i obtained
2453 Spray depo Won The duct surface is coated WiUl re in by spray gun with the chopped glass roving added through a separate nozzle The full thickne i obtain d in layer with con olidation of each layer by hand roller
246 Construction
2461 General M ini mum COllst ructional requireshyments are pe itied ill Tabl 10 for rectangular and Table 1J for circular dUClS
2462 Joints and stiffeners Fig 29 30 31 32 amp 33 hoI TOSS
joint and tiffener for reinforced UPVC and PBPP duct
247 Worki g practices The fabrication of ductwork pecifiecl ill thi document i not affected by the addition of GRP
29
DW154 SfJcdJicatiOt for Plastics Ductwork
Table 10 Minimum constructional requirements shy
Longer Side Minimum Sheet Thicknes and
GRP Reinforcement
UPVC FBIPP 1 2 3
mm mm mm Up to 1000 3 plus 3 plus
06 kgm2 06 kgOIl GRP GRP
1001 to 2250 45 plus 3 plus 06 kgm 12 kgm
GRP GRP
2251 to 3000 45 plus 6 plus 12 kgm 12 kgm
GRP GRP
Cross Joints
UPVCFBPP 4
mm socket amp spigot
as Fig 30 or flanged as Fig 29
75 x 9 flange welded on both sides as Fig 29
75 x 9 tlange welded on both sides as Fig 29
rectangular GRP reinforced ducts
SlifTeners Maximum Spacing Between
JointsSljffeners UPVCIFBIPP UPVCFBPP
5 6 mm mm
75 x 9 flat 800 as Fig 31 or
50 x 50 x 5 plastic or MS inverted angle as Fig 32
or tormer as Fig 33
75 x 9 flat 600 as Fig 31 or
50 x 50 x 5 plastic or MS inverted angle as Fig 32
or former as Fig 33
75 x 9 flat 600+shyas Fig 31 or 50 x 50 x 5 plastic
or MS inverted angle as Fig 32
or former as Fig 33
Note 1 On rectangular duct up to 400 mm longer side no stiffeners are required 2 Applies to Tables 10 amp I I For COlJstructional operating temperature limits refer to Part 2 clause 5A 3 Tables 10 amp II apply to all pres ure classes up lo ]500 Pa
Table 11
Diameter
1 III
lJp to 1000
1001 to 1750
1751 to 2500
Minimum Sheet Thickness and
GRP Reinforcement
UPVC FBPP 2 3
mm mm 3 plus 3 plus
06 kgm 06 kgm GRP GRP
45 plus 3 plus 06 kgm2 18 kgm
GRP GRP
6 plus 6 plus 12 kglm2 18 kgm1
GRP GRP
Cross Joints
UPVCFBPP 4 III
socket amp spigot as Fig 30 or flaoged as Fig 29
75 x 9 flange welded on both sides as Fig 29
75 x 9 flange welded 00
both sides as Fi 29
inforced ducts
Maximum Spacing Between
JointsStiffeners UPVCIFBPP
6 mm 2400
800
600
Stiffencrs
UPVCFBPP 5
mm 50 x 9 flat as Fig 31
75 x 9 flat as Fig 31 or former as Fig 33 75 x 9 tlat as Fig 31 or t()rmer as Fi 33
ote On extruded tube tip to 600mm diameter no stiffenergt are required
30
DW154 Specificatioll for Plastics Ductwork
G - Cross joints and tiffeners
Fig 29 Flange Joint Fig32 Stiffener shy inverted angle
M artiPfCuQkbdd erttpObri) Wl111 RP tlddtlt
_- GRPloliu] lh~
Fig 30 Socket and spigot joint Fig33 Stiffener shy use of former
Fig 31 Stiffener Flat
I Pv FlPP ~ ~lmJaDUA1) d
OMrlQ rrnall 1( tQlS
25 STANDARD COMPONENT DRAWINGS AND ABBREVIATIONS
251 The illustrations in this section not only highlight where applicable geometric limjtations for the de ign and manufacture or ductwork components but also recommend
standard drawing representation terminology and abbreviations for both duetwork components and some of the more commonly used ancillaryplant items
252 Designers and surveyors should note that bills of quantities should provide a full description
3)
---
v
DW154 Spcc(fim(ml for Plastics Ductwork
Fig 34 Linear Thermal Expansion
u c 0 N ro 0)
b 0)
S
sect0
5 oS cl) 0)
~
on ~ ltl
c U
-30 -20 -10 0 10 20 30 40 50 60 70 80 90 TEMPRATURE C
~ V
-
~~c_ ~
~V
V ~
-7 ~
-- ~V ----
v
-6
+14
+12
+10
+8
+6
+4
+2
0
-2
--4
ig 35 Typical Design Stress tor UPVC and P
7
6
r shy 5E
-c E----0 4t) VJ 0)
ci5 0Jl 3
~
0)
Cl
2
1
o
UPVC
1
000
1
1
pp
- r-- shy r----- shy - t--shy I
__0
-30 -20 -10 0 10 20 30 40 50 60 70 80 90 TEMPERATURE C C
Note Figso 14 amp 35 shaded area refers to GRP reinforced duct
32
DW154 Speciicfltirm for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - REC ~NGULAR
Splilt~r Posilion W-mm pliucr
A B c 40]--QOO 1 W - -
601-1000 1 W4 Wf2 -
1001-1800 3 WI W3 W2
FIG DRAWING DETAfiS
tU]36 ATI Straight Duct with socket and spigol joint
rn [037 Straight Duct with flanged joints
[I []38 Straight Duct with flanged joints
rkJ Short Radius Bend
39 Applies to any augl and for duct up to 400 n11n wide
Minimum (I1m31 radills = 100 mm
Medium Radius Bend (a illustrated)
[kJ Applies to any angle
40 Long Radiu Bend Similar but radius = W
Throlll radius = W2 Applies to any angle
- Short Radius Bend with plitlers
I -shy -shy u co - t lt Li--_ 41 t 0 ~ I I I
~ I
L 1W
Minimum waal radius = 100 mm Splitters not required in bend angle less than 45deg
42 QJ1 Square Bend with turning vanes ij
3
DW154 SP(L~ficatioll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - RECTANGULAR
FIG DRAWl G DETADS
43
~
I v
L L Radius Tee with internal deflectors
44
~ Radiussed Twin Bend
45
Imiddot
er Swept Branch
46 U-
Sqoare Tee with Turning Vanes
47
~ f
Breeches Piece
48 0 y l Piece
34
DW154 Specificatioll for Plastics Ductwork
STANDARD COMPONENT RAWINGS - ECTANGULAR
55
54
51
50
53
52
49
FIG
~MX
RAWlNG
DmiddotMAX
EfjMAX
Minimum throat rndius = 100 mm
Rectangular shy Round Transformatioll
Eccentric Taper 225deg max in either plane Spliller are required for angles greater than 225deg and hould bi eet the angle between any side and duct centreline
DETATLS
Angled Offset
OUset Taper Splitters are required for angle greater than 22 0
and shoold bi eet the angl between any side and dUCI centrelinc
Mitred Offset
Concentrk Taper 2250 max in ither plane SpUtters are required for angle greater than 225deg and should bisect the angle between any side and duel c ntreline
Radiussed Offset
35
DW154 Splcilcuthm for Plastics Ductwork
STANDARD COMPONENT DRAWINGS ~ RECTANGU AR
Branch ducl DimCllsions widlh (W) (A)
urnl mm up lO 200 75
300 100 400 125 600 150
Ocr 600 200
FIG DRAWlNG DETAILS
56 poundplusmni~~ Rectan~lar - Flat Oval Transformation
57 [ Square Branch
58 er Angled Branch
Branch dUCI Dimensions wfdth (W) (A)
[- mm mm59 3shy Shoe Branch Up (0 200 75
--shy AIshy + 300 100
400 125
450 MAX 600 150
Over 600 200
Branch duct DimensIOn
rP X width (W) A)
60 - 1--shy _
~ mm mm
Bell Mouth Branch pto 200 75 300 100 t 400 125
600 150 Over 600 200
0=0 61 -
~ Bell Mouth
- shy T 4-5deg M x
--I 1-shy
TJ
62 X I ] I
Tele-scopic Joint I Illustrated with flangeL
X63
SBD Single Bladed Damper
36
---
DW154 Spedicatioll for Plastics Ductwork
STANDARD OMPONENT DRAWINGS - RECTANGULAR
DRAWING DETAILSFIG
64 on-Return DamperNRD shyshy
shyXbull
Multi-Leaf Damper Can be piggoted or flanged oppo cd or parallel blade
Alternative controls areshy
q p [gtshy
J HD65 Hand
~MD otori ed
PO Pneumalic
L-lt
l 13G 66 Blast Gate DamperX X
FireSmoke DampersSleeves
211r Ratinggtshy----
L_-
---
----
r----
Ir-- shy
IL- _-l
2hr
With i tallation frame
67 41 r Rating
4hr
Smoke damper SD
Intumc cent Sleeve L-d
37
DW154 Specijicutiolt for Plastics Ductwork
FIG
68
69
70
71
STANDARD COMPONET DRAWINGS shy REC ANGULAR
DRAVING DETAILS
gtshy Access Openings
AP 6 Access Panel - Rerno able
w [ ~ Access Door - Hinged
I ~le Inspection Cover
le -I reg -lt
~X X Flexible Connection
~ Drop Cheeked Radiussed Twin Bend
U Drop Cheek Bend
I
72 Air Flow SymbolX
38
DW154 Specifim[ioll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - ECTANGULAR
FIG DRAWING DETAILS
73
74
75
76
77
Q
Q
rp---t
~
V- I Ir---I
JL --11
THE ABOVE DETAILS TYPICAL PLENUM
Air Terminal Plenums
Plenum with side connection
Plenum with top connection
Cover plate with connection
Special plenum with connection
elescopic conn ction in direction of air flow
39
DW154 SpecijicotiOll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG
78
79
80
81
DRAWING
-23~---pound3-(MALE) (FEMAJE)
-t=j--_j(--d-shy
--L
~ THROAT RADI S= D AS T NDARD
e ~
THROAT Rjf)lU = D A MU)
DETAILS
Straight Duct With male and female connectors
Straight Duct With flange joint and slip joint
Bend MouldedIFormed Applies to any angle ego 30deg45deg60deg90deg Medium radius bend as illustrated Long radius similar but throat radius 0
Segmented Bend 90deg four section minjmum as illustrated
Other Angles 60deg = 3 sections 45deg = 3 sections 30deg = 2 sections
I
i
40 shy
DW154 Speciicafinll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG DRAWING DETAlLS
82 Segmented Twin Bend Radius = D2 max
May also be fabricated from tube
83 Equal Tee MouldedIFormed
84 -~ 1in Bend MouldedIFormed
85 Taper Concentric 1 0 as iUu trated Eccentric 30deg iJJcLuded angle
86 Short Taper
41
DW154 SpcUicatol1 for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG DRAWING DETAILS
87 30 max Offset
Angle Branch
Bran h dUCI Dimcnsions dia (D) lA)
Shoe Branch mm mm 88 Cl
Off rectanguJur Up 10 200 75 lOO 10 400 125
- 00 150 Over 600 200
Bl1IllCh duct DimenlOns din (D) (A
~-$a-Conical Branch mm mm
89 Also acceptable with Up 10 200 r
full conical surface 300 10
400 125
END VrE -shy 600 150 Over 600 200
90
m 75
100 12 150 200
mm Up to 200
_ 300 400
600 Over 600
iUtred Branch
Shoe Branch
J-L----U ~ Bell oulh Branch
ENDV1EW
93
92
91
42
DW154 Specificatiol for Plastics Ductwork
STANDARD OMPONENT DRAWINGS - CIRCULAR
FIG
94
DRAW G
I
~ 30deg 090deg
Breeches Piece
DETAILS
95 amp-----~ Blank End
~-----p Multi-Leaf Damper Can be piggolcd or fianged opposed or parallel blade
Alternative controls areshyri=-+- L-T~
I
---
LT~
I r- -
-+1
J HO Hand96
bMD Molori cd
PD Pneumatic
tl-shy bull
Single Bladed Damper 97 ~ saD
on-Return Damper Vertical application only 98 m~D
43
DW154 Sf1tcificatioll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG
99
100
101
102
DRAWING
$ I-
2hr
1 4hr
SD
~v I I
CO TINENTAL COWL
DETAILS
Iris Damper
Fi reS moke Dam persSleeves
2hr Ratillg
With installation frame
4br Rating
Smoke damper
Intumescent Sleeve
Access Openings
Access panel - removable
Access door shy hinged
fnspection cover
Discharge Continental Cowl
44
DW154 Sp(Cii(ltJll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
DRAWINGltIC DETAns
-
I
I
~
I I I High Velocity Discharge Terminal 103 I
I
I I
J I I 1 ~--
Offset Stack Discbarge Terminal 104 1
~ I e --(-
I
N
I
I
I~
I I Vertical Oischarge with Weather Cowl 105 I
--1--1 I
I
GAPI I
RTl AL DISC) lARGE WITH W ATIIER COWL
45
DW154 SpecUicatoll for Plastics Ductwork
STANDARD COMPONE T DRAWINGS - PLA TEQUIPMENTIMISCELLANEOU
FIG DRAWING DETAILS
106 ~~~ Rectangular Attenuator
107 ~- Circular Attenuator
108
~ Beod Attenuator
109 J ~(f) Heating Coil
110 J ftte Cooling Coil
III Jc[ Electric Heating Coil
112 X F
Humidifier
113 [H XX Axial Fan
114 ~fB1famp Noo-standard Ductwork Cross hntchillg (of any separate type) indicates by reference to a key any non DVil54 ductwork system
115 2llIIIIJIIIIIll Flexible Ductwork
46
DW154 SJeCUicll(iol1 for Plastics Ductwork
TABLE 12 - STANDARD ABBREVIAT ONS
ABBREVIATION FLL
AD Acces Door
AFF Axial Flow Fan
AHU Air Handling nit
All Aluminium
AP Acess Panel
AT Attenuator
AV Air enninal Unit
BE 81ank nd
BQ Blast ate Damper
CC Cooling Coil
CF Centrifugal Fan
CTA Cross alk Attenuator
CVU Constant Volume Unit
DP Drain Point
EEC Electric Heating Coil
El Expansion Joint
FAl Fresh Air Inlet
FA From Above
FB From Belo
fBPP Fabric Backed Polypropyl-ne Sheet
Flexle Flexible Connection
lexfD Flexible Du t
C False Ceiling CO an oil Unit
fD Fire Damper
FFL Finished Floor Level
FJ Flanged Joint
FOAM Rigid Polyurethane Self xtinguishing Foam
FOB Flat on Bottom
FOT Flat on Top
GAM Galvanised after ManufacttrJc
GRP Glass Reinforced Plastic
GSS Galvanised Sheet Steel
HC Heating oil
HD and controlled Damper
HH Hand Hole
HL High Level
HVD High Velocity Discharge
IC Inspection Cover
ID lri Damper
IFS Intumescent Fircleevc
47
DW154 Specification for Plastics Ductwork
TABLE 12 - STANDAR ABBREVIATION CONTINUED
ABBREVIATION
IU
L
tv1D
MS
NRD NTS
OBO
OE
PHD
PD
PP
PP
PRD
PVC
RFC
RSC
R
SBO
SO
S1 TST
SSL
TA
TB
TO TJ
TP
TV
TV
OS
UPVC
S
V
VAV
50 RSA
FULL
Induction Unit
Low Level
Motor controlled Damper
Mjld Steel
on Return Damper
at to cale
Opposed Blade Damper
Open End
Parallel Blade Damper
Pneumatic controlled Damper
Polypropylene
Self xtinguishing Polypropylene
Pressure Relief Damper
Polyvinyl Chloride
Rolled Form Chamlel
Rolled Steel Channel
R fUnit
Singl Blade Damper
Smoke Damper
Slip Joint
Stainl t el
tructural Slab Level
To Ab vc
To Blow
Top Down (In Direction of Flow)
Telescopic Joint
Test Point
TU111iog Vane
Top Up (In Direction of Flo )
Voles Otherwise Stated
Unpl3sticisecl Polyvinyl Chloride
Underside
Ultra Violet Light
Variable Air Volume
Rolled Steel Angle (Vith Size)
48
DW154 SJeriiflllioll for Plastics Ductwork
A2 DUCT PRESSUREAPPE DXA Ductwork con truct d to DWIl54 will bebullbullbullbullbullbullbullbullbullbullbullbullbullbull
Air Leakage From Ductwork To be read in conjunction with DW143 A practical guide to Ductwork Leakage Testing
CAUTION As highlighted ill both this docul1lenr and DW14 I lot ellough emphasis can be placed 01 the fact that except for high pressure class C the much more stringent ductwork constructional standard brolght about b the general acceptance of DW154 have irtlally negated the requirement for leakage-testing It is essential lO realise lhat except where it is mandatory this doclllllelll is nOl an endors ~lIlent of the rourine testing of ducts bllt purely a guide to outline the procedures for cononnity with the air leakage limits ill Table l Where the specified methods of assembly and
A3sealing of dlcls are u ed a vi ual inspection wil ordinarily sl~fll e for ver(iatioll of a well engineered and a ceptahfy airtight COl1strucrioll WHERE NOT MANDATORY DUCT LEAKAGE TESTING IS GENERALLY AN UNJUSTIFIED AND SUBSTANTIAL EXPENSE
A1 INTRODUCTION L akage from ducted air distribution systems is an Lmportant consideration in the design and operation of ventilatjon and air conditioning middotystems A ductviork t)ystem tbat ba limited air leakag within defiucd limits wiH cnsUft
that tile design characteristics of the sytem can be maintained It wilJ also ensure that energy and operatLonal cosb are maintained at optimum levels DucLwork constlucted and Ulstalled in accordance with DW154 should minimise a level of air leakage that it) appropriate to tll operating static air pre sur in tile system
A4However it is recouuised that tbe environment in wtJich middotystems are installed is not always conducive to achieving a predictable level of quality in term of system ajr leakage and it is therefore accepted that designer may sometimes require tlle ystem to be tested in part or in total It should be ecogni ed that the testing of duct systems add a ignificant cost to the installation and incur some extra tjm within the programme (Se 47 and 64 re mandatory te-sting)
manufactured to a structural standard that is compatible with the system operating pressure There are three classes of duct con truction to eorre pond with the three pre ure clas meations Class A Lo pressure ducts suita le for a maximum positive operating pressure of 500 Pascal and a maximum negative pressure of -500 Pascals Class B IVledium pressure ductmiddot suitable for a rnaxilnuJJl positive operafjn o pressure of 1000 Pascals and a maxllnum negative pre sure of -750 Pa cal Class C High pre sure ducts suitable for a maximum po ilive operating pressur of 2000 Pa cals and a maximum negativ pres ur of -750 Paltcals
LEAKAGE FROM DUCTWORK Leakao-e front pia tic air ducts occur at the joint~ and is therefore proportional to the total surface area orthe du twork in th system Tb level of leakage i imilarly related to tIle air pres ure in th du t system and whilst there LS n precis formula for calculating the level of air los it i generally accepted that leakage will increase in proportjon to pressure to rbe pOvver of 065 The effect of air leakage from high pressure velocit ductwork is critical tn terms of system perfomlan dege energy consumption and the risk of high frequency noise as ociated with leakage These problems are le critical with medium pressure 10 ity systems but should be con idered Low pres mevelocity ducts present the lowe~t
ri k in tenn of tbe effect of leakage on the operation of the s stern
SYSTEM LEAKAGE LOSS As there i no di ct relatLonship between th volume of air conv yed and the surface area f the ductwork sy tern required to match the building configuratmn it is difficult to express air leakage a a percentage of total air volume Similarly the operating pressure will vary throughollt lh 3 system and a leakage is related to pre me the calculations ar comple However it is generally ac epted tbat in typical good quaJjty systems the leakage from
49
DW154 Specificatioll for Plastics Ductwork
each class of duct llnd r operating condition will be io the region of CIa S A low pressure 6 Clas B medium pres un 3 Clas C high pressure 2
A5 SPECIFYING AIR LEAKAGE TESTING Re peeting both the co -t and programme implications a sociated with te ling du 1 for leakage the designer may for example indicate that a particular system is te ted as follow
a) High pressure ducts - all tested b) Medium pr ssure duets - 10 of the
ductwork shall be s eet d at random and tested
c) Low pre sure - unte ed In any case where a random te t i elected for medium pre sure ductmiddot the followin c1au~e is suggested for inclusion by the de ign r
The designer hall elect at random a maxirnwlI of 10 of the dUCl system to bt tested for air leakage The duct hall be tested af the pressure recommended in Table J3 for the assifi atiol for the ectiol1 of the ductwork that is to be tested The tests shall be carried Ollt as the work proceeds and prior to the application of thermal insulation In the event of test failure of the randomlY selected section the designer shall have The right to select two La1her e tiolls at random for resting Where succes ive failures are identified there shall be a Tight to require rhl COl11raCWr 10 apply remedial attention to the complete ductwork system Th contractor shall provide documented eviden e of the calculalions used to arrive (1
the allowable 10 I for the section to be tested and the client or his agent shall willess and sign the results of the test
able 13 Air leakage rates
Maximum leakage of duct work Static
prcssUft Low-pressure edium-prc-sure I Iigh-prebull me diJfercntial Class A Class B Class C
1 2 J 4 Pa Litres per second per quare metre of surface area 100 054 018 ZOO 084 028 300 110 037 400 132 044 500 153 051 600 058 019 700 064 021 800 069 023 900 075 025
1000 080 027 1100 1200 1300 1400 1500
029 030 032 033 035
1600 1700 1800 1900 2000
036 038 039 040 042
Note Recommend d mean test presures are highlighted iD bold type with the actual selection being left to tll test operator
50
DW154 Sfeeiieaioll for Plastics Ductwork
A9
A10
and air leakage classification for the y em under test
DESIGNERS CALCULATIONS The designer can middotaJculate with reasonable accuracy the predicted total loss from a ystem by
a) Calculating the operatin presure in each ection of the sy tern
b) Calculating the surface area of the ductwork in each correspondin pre lire s ction
c) Calulating the allowabl~ los at the operating pressure for each ection of the system (see table 13 for allowable leakage figures)
VARIABLE PRESSUR S IN SYSTEMS De igner can achieve significant co t saving by matchina operating pressures throughout the system to constmctional standard and appropriate air leakage testing eO the practice of specifying construction tandards for whole duct sy tems based on fan discharge pre sure may incur unnece sary costs on a project For example ome large sy terns ould well be classiC ed for I akage limits as follows
Plant room risers CJas C Main floor distriblltJou CIa B Low pre sure outlets Cla A
A6 SPECIAL CASES There may be ~itLlations on a project where circumstance dictate thal pecial consideration be given to containing air loss s eg a long mn of duclwork may incur a di -proportjonate level of air 10 s In ca es such as thi example the designer can specify an improved tandard of airtighmess ie 80 of alJo~able 10 s for la B Ju ts The designer sbould not specif a CIa C t sI at CIa s C pressure for a CIa s B ducl
A7 SUGG S ED RANGE OF TES ING
A8 TESTING OF PLANT ITEMS Items of inline pJant (eg Fig 106 to 115) will not normaUy be included in an air I akage test The dllctwork contractor may indud such itelllS in tbe te t jf rh quipm ot has a certificate of COnfOlnlity for Ihe pres ure clas
bull High pressure duct bull Medium pre sure ducts bull Low pre sur ducts bull Exposed extract syst ID bull Ceiling void extract
systems bull Secondary ducts from
VAV or fan coil units bull Flexjble duct bull Final connections and
branches to grille and diffusers
100 test See A5 Untested UDt sted
Untested
Untested Untested
Untested
SI
i
DW154 SJecijicafion for Plastics Ductwork
ig 116 Permitted leakage at various pressures
Leakage in litres per second per square metre duct surface area
Vgt
o ltgt 0 ltgt N
ltgt Cgt
0 0 cc
0 0
~
g =
g ~
c 0
J
ltgt 0 I
~ ] tn
ltgt ltgt
In ol
~ 0 ~ 8 ~
~
c ltgt ltgt
~ CJ
~ ~ ~ ~ 8
0shyij
~ ~ ~ t
ltgt ltgt 00
l
~
~ Q
c C
~ rshy
e ltgt
I 1
I Cgt ltgtv
c Co ~
~~ ~ 10
I
0 Cgt
fJshyq 410 ) 1 ltgt
ltgt N
~ shy ltgt ltgt
~ I 1
c
52
DW154 Specificatio for Plastics Ductwork
Example of a completed test sheet Test No
General
Name of job N~ jC43Pt(r2lef Building Repound ~(~~0
Part 1 - Physical details
a Section of duct work to be tested ~(diffPIfff~el1f3rd Floor
b Drawing Number g91~~ c ssure aSSJ L atlOn V~Jl~IRfYgtg~~lPre Cl T Class C
d Test static pressure -(9 raErq~ ~~~~-~~J~~~ ~~ ~~~~ll
Leakaoe factor 9~-tre3$ecMz I OM REFTOTABLE 13)e b bullbullbullbullbullbullbull
f Surface area of duct under test Q~tJJItetre$ CPROMCALCU TIO BELOW)bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull ampampamp bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull
g ]Vlaxi mum permitted leakage -~ (~i~~0 ~~r~~ ~~~l-~-11~ ~~~Q
Part 2 - Test particulars
a Duct static pressure reading 9QFt~q~ ~ middot~~~1 ~~
b Manufacturer and type of liow measuring d vice (-~~~cJ~Y-9Q7EYg c Range of measurement of now measuring device QtP)OQ~(e~~~0I~~~~1~I~ ~~~~~~W~
d Reading of flm measurin o device pmiddot IFROM RIO)ftscag ~
I (DERlVED [ROM CHART SUPPUED WITH RIG US 0 ud)1e Interpreted air flow leakage rate ~(~~~f~~~ (~l~~~~~~~~~~~~~~~~~I
f Duration ~~~~~norn~allY l~ lnil1Ut~~d~~~ it1~ W~ Date of test ~(lITled ut by Wltll s ed by ~ ~
(~lJ MIJLrr) (Si~rrfltJUYJ
Printed Name 1~g0f~ Printed Name ~~Y~9~ and Company 7jl~~~~~( UJd CompanY AB COII$Itallt8
Width and depth or diameter
Periphery ength Area
millimetreS millimetres metre qL1are metre
800 x 750 3100 1755 5440
600 x 650 2500 557 1193
300 x 300 1200 120 144
305 din 958 700 670
250 dia 785 450 353
TOTAL 8000
53
DW154 Specijilarion for Plastics Ductwork
pA XB
Guida ce No es For he ransport Handling and
Storage of uctwork
avoid damage to adjacent duct panels In somc ca es particularly on con acts calling f r repetitive sizes the use of timber jigs and spacers may be justified Where reduced bulk and greater protection are major factor such as consignments for export transporting ductwork in L shape sections may justify the increa ed ite as embly co ts
It is recommended that before a contract is finalised that consideration is given to the subject of site acces material handling and storage as tbcy havgt a strong influence on the cost efficiency of the overall activity of ductwOlk installation
B3 Handling To minilnise th risk of damage duct sections should be clearly identified and deliveries to site should be closely linked to the installation programme so as to avoid accumulation of
B1 Storage and Handling of Ra Material Material should be stored in suitably designed racking out of direct unJight Where possible the e racks should be metal to earth Edges of cut she t may be harp and protective gloves are advised Wearing teel toe-capped boots is recommended Most pIa tic sheet is manufactured with smootb mfaces andor is suppLied with protective coating Care must be taken to prevent accidental lippag of stacked materials Beiuoshy good electrical insulators the movement of stock unless earthed will allow the build up of stati All stock shapes are chemically stable at normal temperature Whil t some raw materials used in their manufacture may themselves pre ent a toxic hazard once incorporated into the lOck bape they no long r constitute such a hazard and no dermatitic bazard are known nor are any
unfiJied ductwork and minimise double handling It is important to recognise that ductwork panels joint and corners arc susceptible to damage and care must be taken wheu band ling such material through a site During handling individual item of duct work may be liable to light cross sectional deformation until thev become an integral pan of a completed ductwork system Whilst this may temporarily detract from its intended appearance thi deformation will not have any detrimental effect on the functionality of the finally a semblecl system Installation of duct work and asociated plant items ill illevitably involve manual handUng The responsibi Iiry of employers and employees to a ses the risk of personal injury during mallual handling operations is et out in the HS E publication L23 Guidance on Manual Handling Regulations 1992
environmental problems expected 84 Site storage
B2 fransport Large capacity vehicles with high-sided open or closed-top bodies are tlle mo t suitable for the transport of dllctwork Careful consideration should be given to the
Adequate floor space IDust be provided within tbe building for the site storage of ductvork Such storage shalt make due allowance for thc stOf(ne of ductwork in stacks such that access ~ egt
between them is of sufficient width to pennil the removal of item without interference to
unloading of transport on sit a not all siJes b n fit from the material handlino- and access facilities that exi [ in a manufacturing workshop such as crane- fork-lifts or loading bay Site handJiog facilities along with
adjoining sta ks Ductvork components should be positioned so a to avoid crushing Ductwork of small panel size may be stored horizontally however care should be exercised to ensure that tack sizes are limited 10 within
ehicular acce s restrictions may itilluence the type and ize of transport to be uWised
engtlls of ductwork should be positioned 0
the tmctural strength of the duct sections to prevent distortion of the lower sections within the stack
as to avoid crushing Lengths Witll projections such as branches and bends i1anges girths damper quadrauL should be loaded so as to
54
DW154 S1tciic(ltioll for Plastics Ductwork
85 Internal cleanliness of new ductwork The site storage of ductwork introduces the important cODsideration of maintaining the internal cleanliness of the ductwork R feren e should be made to HVCA documentshybull DWffM2 Guide to Good Practice - internal
Cleanliness of New Ductwork Installations If the above conditioDs can not be satisfied consideration should be given by tJle designer to amending the specification to include for Po t Installation Cleaning as covered by tJ1C HVCA documentshybull TRJ17 Guide to Good Practic - Cleanliness
of Ventilation Systems
APPE DIXC
Fi e Retardant inishes C1 Improvement in the fire retardancy of plastic
ducts can be achieved to varying degrees and is wholly dependent llPOll the surface coating laminating resin selected and construction specification adopted In some instances smoke emission is coILSidered equaUy with other speci fication requirernen ts of the materials resistance to ignition and bumjng It is therefore important for design rs to establ ish the clients and officers detailed requirements and not rely on a tbird party interpretation of fire resisting or fire retardant Where possible the specification should refer dir etly to compliance with a British or European Standard identifying the specific sections applicable There are various types of resin and mat rcLnforcements that can achieve a Class 1 surface spread of flame ratin o when tested according to BS476 Part 7 (1987) This test puts materials illto Class I - 4 in descending order of perfoDllance according to the rat and extent of flame spread over their surfac under standard beating conditions Materials should also be tested for flre propagarion to BS476 Part 6 (1989) Tbi tesr measures the amount and rate of heat evolved by the material when subjected to standard heating
conditions Test results are given as an index of Perfonnance (i) whicb is based on three sub indices (iJ (i1) (h) The higher the value of the Index of Performance (i) the greater is the material s contribution to fire growth The higher the value of the sub-index 0) rhe greater the ease of ignition aod flame spread The highest product performance classification as defined in Approved Document B of the Building Regulations is Class O This is acLlieved if a material surface of a composite ploduct i~ either a) composed throughout of materials of
limited combustibility or b) a Class I material which has a tlre
propagation index (i) of not more than 12 and sub-index (i l ) of nor more than 6
01 J Class 0 is not a cla$sif1cation identified in any British Standard test
There are resin system reported to be classified to Class O when tested to BS476 Pcl1S 6 and 7 however designers need to ensure that such sysrems can be applied to their proposed design In propriety resinmat system available the fabrication techniques and COITect application are critical to the integrity of the reinforcing and clas ificatiol1 For example in some systems the u e of a non-fire retardant gelcont on a fire retardant substrate would reduce the classification For further information see HVCA publication DW144 Appendix D
55
DW154 SplCijiClIliol1 for Plastics Ductwork
x Guidance otes For nspectmiddoton Servicing a d
Clean-ng Access Openings
D1 GE ERAL This appendix highlight in ummary fOI111
the acce considerations that hould be made by the design r iD terms of inspection servicing and cleaning Having considered the seop and the design of the dUCI work system relative to the guidelines outlined below the designer should clearly indicate which levels of acces should be incorporated into the manufacture of a new duct work system (See Table 14 and Note I b low it
D2 DESIGN CONSIDERATIONS
D21 In ptction and servicing requireshyments are set out in Section 15 of Lhis specification
D22 Cleaning requirements are set out in the HVCA pubUcation TRl7 Guide to Good Practice Clean Lines of Ventilation Systems and the guide tates The precise location ize and
type of access would be dependent on the type of ductwork cleaning inspection and te ting metbods to b adopted Care protection and standards of cleanliness prior LO cOlllmisionin o
are set out in th AV A publication DWITM2 Guide to Good Practice Internal Cleanliness of New Ductwork Installations and th guide state Wh re specific limits of cleanliness are required ductwork sball be cleaned after installation by a spcialist cleaning contractor It will b in the interests of tht desioner botb financially and practically to cunsider employing a specialist c1eauing contractor at tbe
outset of a contract to internally clean newly installed ductwork prior to bandover This approach would reali e the following benefit shyi) Tb actual numb r of cleaning
access panels could be detennined to suit the method of cleaning to be adopted (This may be 1 s than the maximum requiremen listed under Lev 13 of Table 14)
ii) Clear directions could b given to the ductwork contractor as to tJle size and location of cleaning access panels that are required to be fitted during the mauushyfaclunng pro s
iii) The specialist cleaning operation prior to commi ioning vould enable the cleaning contractor to verify the practical acee requirement for the future cleaning operation associated -vitb a regular maintenance programme
iv) A specialist cleaning operation prior to commissioning would allow the designer to omit from the speeilicatiolJ the DWrrM2 requirem nt for factory sealing protection wipe downs and capping-off
v) Specialist Ieall ill 0 to the measurable standard defin d in TR17 will allow an objective definition of cleanline to be achieved
Car ful consideration must be gIven by the designer to the practl aJ problems associated witb the manufacture and fitting of suitably si Led access panel on small cross section duct and on the circular faces of rouod and flat oval ducts in particular
D23 Special con ideration must be given by the de igner to the practical problems associated with gaining personnel access to heavily congested ceiling areas and multi-la red du twork systems This approach would avoid
56
DW154 Spfciication for Plastics Ductwork
the possibility of access panels being D3 ACCESS 0 IN-LINE EQUIPMENT incorporated into a ductwork system at the This appendix unly covers acc il1spection manufacturing stage that were later found in through the ductwork body adjacent to an item practice to be inaccessible for either ervicing of in-line equipment and not openings in the or cleaning activities equipment itself
able 14 Acce requirements for inspection servicing and cleaning
HVCA PUBLICATIO REFE NeE (uidtgt 10 Gund Prartict
Adjace t OW144 Cleanliness orVcnlillltio S~lcr~ fRjJ7
in-line LeyeJ 1 Level 2 Level 3 ite sequipment pcdionSen lcin~ Section d C1eaniJl( SUn(O)lnspc lion Palle ltk~m_n
2011 (minimum OiL Jubje-ct to duct ~zel (ft~ -Panels
Control Da pcrs One (inspection) 203 One 300 mm x 200 mm Both sid Fire Dampers One (sCTjdJl~) 20211 One 300 0101 x 200 mm One side HeatingCooling Coils One (inspedion) 20213 One 300 mm x 200 mm (lIpstream) Both sides Attenuators (rectangular) None required One 300 mm x 200 mm (downstream) Both sides Attenuators (circular) one retluired One 300 mm x 200 mm (downstream) One side Filter Sections One (inspection) 20212 one required Uoth sides Air Turn Vanes None requjred None required Both sides Changes of Direction None required one required One side In-Duct FansDevices One (inspection) 20213 None required Both sides l
1 In the absence of any indication by the designer only Level ) access will be jncorporated into a new ductwork system
2 Tbe panel izes associated with Lev lis I and 3 acee s ar e middottablished by reference to Section 20 of DW144 and Section 2 ofTRll7 respectively
57
DW154 Speclfifatio for Plastics Ductwork
pA XE
B-bliography Included in this Bibliography are technical pUblications which may be of interest (0 ductwork designers fabricators and erectors and to tho e in the heating ventilatlng air conditioning industries generally nquiric should be made of the relevant organisation at the address quoted Since its publication other addresse contained within 0V154 mav have changed and some pubJicalions may have been superseded
HEATING AND VENTILATING CONTRACTORS ASSOCIATION
4 Palace Court London W2 4JG Telephone 020-7229 2488 Fax 020-7727 9268
Orders fo FlY A Publications Old Matlsion House Eamont Bridge Penrith Cumbria CA 10 2BX (Telephone 01768 864771 Fax 01768 86718) Email hvcapoblicationshvwelfarecouk DWn 44 pe ilicatiun for sheet mctal duclwork (Iow- mediulllshy
and high-pressure) 1998) DWIl4 A practical guide to dUGI ork I akage te ting
(revised 2000) DWII54 Specification for plastic~ duct rk DW171 Guide to good Practice for kitchen venlibtion system DW191 Guide to good pracuce glass fibre ductwoJk DwrrMI Acceptance cheme for new products - Redangolar cro
joint classification Guide to good pra tice - Internal cleanliness of new ductwork installations Guide to good practice for the design for the Installation of lire and smoke uampers
J 1Other puhlications
HampV safely guide 5th edition JS2 Tool box talks JS5 Weldlng Safety booklet JSI9 afety facts bo klet Fact sheets 1-24 2nd edition JS2J COSHH manual volume 1 Advice on compliance with the
regulations 1521A CO I-rH manual volume 2 Asses mcnt h ets JS23 Ri k management manual TR3 BrazinltT and bronze welding of copper pipework cUld sheet
(I 976) TR5 Welding of carbon steel pipework (1980)
TR6 Guide to Good Practice for Site Pre sure Testing of Pipework (19 0) Guide to good practice cleanliness of ventilation Ylem
CHARTERED IN TITUTlO OF BUILDING SERVICES E G EERS Delta House 222 Balham High Road London SW12 9BS rTelephone 020-8675 5211 Fax 020-8675 5449) CIBSE Guide Volume A Design Data Volume B In tallatiol1 and quipment Data Volume C Reference Data
CommlssioniJIg Codes These Codes eover the preliminary checkS eUing to work and regulation of vanous catcgories 0 plan The Codes give a guide to design implications Series A Air Distnbution Systems Series B Boiler Plant
ri s C Automatic Conlrol ystems Cr1es R Refrigerating Sy terns
Sene iN Water Distribution Systems
Technkal Memonllda TM 4 Design Notes for the Middle East TM bull Design otes for Ductwork TM 13 Minimi iog lhc Risk of egiounaires Disease
Research Reports RROI95 Ventilation system hygiene - A review of published
infomlatioo on lhe occurrence and ffects of Olltamination Rl~02J95 Air-to-air heal rec v ry RR0395 rnfluen e of HV C on smoke detectors
ATlONAL ENI [ERING SPECIFICATION LfMITED Southgatc hamber 3739 Southgate Street Winchester S023 9EH (Telephone 01962 842058 Fax 01962 R(8982) BUfLDING S RVICES RESEARCH AND [ ORMATION ASSOCIATIO Old Bracknell Lane West Bracknell Berkshire RG 12 4AH (Telephone Brackl1eU (01344) 426511 Fax 01344 487 -7 )
Application Guides AGln4 De tglJing Vana~le Volume middotylans for KOOnl
iir Movement AG1I91 Commissioning of V Sylcms in Buildings 11 6194 Fire Dampers
B) 94 cntiJalion or KitcneTls
AG389 The Commls ionin of Air Systems In Buildmgs AH2192 Commissioning of Bern - A ~ode of Practice TN2417 I Fire Dampec il) Ventilating Ducl
BEATING VENTILATING A AIR CONDITION G MA UFACTURERS ASSOCIATIO (HEVAC) HEVAC Henley Road Medmenham Marlow Buck SU 2ER (Telephone 01491 578674 ox 01491 575024 Emoimiddot infofetacouk)
Publicatjons Air Diffusion Guide Guide to Air Handling Unit Leakage Testing Guide to Good Practice Air Handling Unit Real Room Acoustic ~ st Procedure Specification for the ertiiicatioll ofAir Filters Method of Test for Water Rejection PerfOnTlatce of Louvrcs Subjected 1(1
Simulated Rainfall Test Procedure for Acoustic Loo cs Specification 10 Floor GrilJes - Types Performan e and Method ofTest Specification for the Determination of the Collection Efficiency of SilJ1d
Trap Louvre Domestic Mechwlical Vclltllalion Systems with Heal Recovery Fan Application Guid
~an and Ouctwork Installation Guide Guide to Fan Noise and Vibration
pecification of Requirements for JallJral Smoke and Heal Exhausl Ventilators
pecification for Powered Smoke and Heat Exhaust Ventilators
Specification of Requirements for Smoke Curtains Design Gujue of Smoke Ventilation for Single Storey Lodustrilll Building~
Including those with Mezzanine Floor and IIi Racked Storage Warehou es - Issue 3
Guidance for the Design of Smoke entilation YSlem for Covered and Undergrollnd Car Parks - lssue 1
Application of SOloke Control Equipment and Syst m Guid to Good Practice - Isue J
58
DW154 Sp(C~tiifitiol for Plastics Ductwork
BRITISH STANDARDS INSTIT TION Sales Department 101 P ntooviLle Road London NI 9ND (felephone 020-78 1 78801)
CP 413 1973 Ducts for building ervices
SS 476 Fire tes on building matenals and lruc(ure
Part 4 19 4 Non-combustibility lest or materials
Part 6 I Fire propagation lest for materials
Part 7 1993 Surface spread of tlarnJ tesls for materia
Part 20 1987 Fir resistance of elements of construction
Part 21 1987 Fire r sistlUlce of loadbeanng elements of construction
Part 22 1987 Fhe istallceofllon-loadbearing elemcllts ofconsttuclion Part 23 1987 Contribution of componcnts to the fire resistance 0 a
structure
Part 24t987 Fire resi lance of wl1lilation ductl
SS 5588 nan 919 0 Fire Precautions III thc desIgn and OOSlnJ lion of buildings
S 729 1971 Hot dip galvanized oatiugs (or irOIl aod stcel articles
BS 1449 Steel plate sheet and Irip
Pan 11991 Carbon steel plate heel and strip Part 2 1983 Stainless steel plate sheer and strip
and
B middotENJOI49-2 996 BSEN 10149- 1991)
BSEN 10131 1992
BSEN22063 Sprayed metal coarings 1994 Protection of iron and steel by aluminium and zinc against
atmospheric cOlosion Irotectiotl of iron and ste I against corro ion and oxishydation at elevared temperatures
BS 353 1981 Glossary of lerms relnting to thermal insulation
BS ISO 1479 Self-tapplngscrewsandmetallicdri c crew
B -lSO 7049
1994
B 4800 1989 Painl colour for building purposes B 4848 l0 rolled structural steel sections
Part4 1972 Equal and unequal angles BS 5422 1990 Specification for the use of therm illuating matcriulS
SS 5720 1979 ode of practice for mechanical veutilating and air C 11shy
dirionin bull in building
l3S PR 12814-1 Bend resting for plasric welds
SS PR 12814-2 Tensile testing for plastic welds
SS PR 13067 Appro altesting for plastic welds
BS PR EN I 100-] Vi ual in pection ofplaslic welds
SHEET METAL AND AIR CONDITIONING CONTR-CTORS NATIONAL ASSOCIATION INC (SMACNA) Headquarters 420 I Lafayeue Center Drive Chanlilly Virginia 2051-1209
Mailing Address pa Box 221230 Cbantilly Virginilt120 153-1230
Telephone (703) 803-2980 Fax (703) 803-3732
Accepted IJJdustry Pl3Gtice for Industrial Duct Constnlelion 197 ) i-rchitecmral Sheet kwl Manual ([993)
Comractors Guide lor Modification 10 ooslruerion Colllraets 1993 Ducted Eleclric Heat Guide for ir Handling Ssrerns (1994)
En~rgy ollservatioD Guidelines (1984) Energy Recovery Equipment yslClllS (199l
Fibrou GIns Duct onS1ntClion Standards (1992)
Fire Smoke amp Radiation Damper In tall Guide for HVA Syst ms (1992) Guide t leel Stack 1(95)
HVA Air Duct Leakage Test Manual (19 ) HVA COlllmissioning lvlanual (1994)
H A Duct Construction Standards-Metal amp Flexible (1995) Addendum 01 (Nov 1997)
HVA Duct Systems Inspection Guide (1989)
HVA ySlems-Application (1986) nVAC ByternS-DLlct D ign (1990)
HVi Systems-Testing Adjusting amp Balancing (1993)
indoor Air Quality Manual (1993) tcheu quipment Fabrication Guidelmes (1990)
Managers Guide for elding (1993)
Rectangular Industrial Duct Cons1TUction Standards (19 0) Round Industrial Duct oustmction Standards (1977)
Sei mic Restraint Manual (1991) (wl Appendix E 1993) SMACNA Ma le Index ()fTechnical Publications (1995) Tbennoplnstic Duct CPY ) Construction Manual 1994)
DEPARTME OF THE ENVIRO MENT (Publications Centre) H Stationery Oflice 5 Nine Elms Lane London SWS 5DR
MampEJ 011972 Electrical in tallat1011 in buildings ( ew Editiou)
IampE 0319 Healing hot and cold wat r steam and gas losla1lations for buildings
M amp - No4 1970 Central heating and hot and cold ~ ateT in tallations for
dwelling
M amp ENo100 1971 Mechanical ventilation for building~
ASSOCIATION FOR SPECIALIST FIRE PROTECTlO As ociation House 235 Ash Road AJdershot Hampshire GUl2 4DD
Telephone OJ25221322 Fax 0 J252 333901
lublicalioos Fire Ratcd and moke Outlet Ducrwork An Industry Guide t Design and InSlalla lioll
HEALTH AND SAFETY EXEC TIVE Rose Court 2 Southwark Bridge London SEl 9HS Telephone 020-7717 6000
TWJ THE WELD G TlTUTE Abington Hall Abington Cambridge CB16AL Telepbone 0 J223 89162
Publication DatJ Oil w~ldll1g of lhermopla lics
59
DW154 wciiwlioll for Plastics Ductwork
A -=--DIX
Factors
Specific gravity shy pp = 091 approx UPVC = 14 approx
Some miscellaneous conversion factors
To convert
Length Inches to millimetres Feet to metres
Multiply by
2540 03048
To convert
Millimetres to inches Metres to feet
vIultiply by
003937 3281
Area Square inches to square millimetres 6452 Square millimetres to square inches 000155 Square feet to square metres 00929 Square metres to square feet 10764
Volume Cubic feet to cubic metres Cubic feet to litres Gallons (UK) to litres
002832 2831 4546
Cubic metres to cubic feet Litres to cubic feet Litres to gallons (UK)
35315 00353
022
Mass Ounces to grams Pounds to kiJograms Tons to tonnes
2835 04536
1016
Grams to ounces Kilograms to pounds Tonnes to tons
003527 2205
09842
Volume flow Cubic feet per minute to cubic Cubic metres per second to cubic
metres per second 0000472 feet per minute 2119 Cubic feet per mIDute to litres Litres per second to cubic feet
per second 04719 per minute 2119
Motion Feet per minute to metres per second 000508 Metres per second to feet per minute 197
Pressure Inches water gauge to millibars 2491 Inches wateJ- gauge to pascals (Pa) 2491 I Pa = I ewton per square metre = 10-2 millibars
60
Heating and Ventilating Contractors Association Esca House 34 Palace Court London W2 4JG
Tel 020 7313 4900
e-mail contact Itvcaorguk web site wwwhvcaorguk
Fax 020 7727 9268
DW154 SpeciJimlioll for Plastics Ductwork
leakage Iim its sp cified for th c1uctwork ystem to which tbey are installed
In order to apply the square metre leakage calculatio as detailed in DW143 A Practical Guide to Ductwork Leakage Testing the reference casing area ball be taken as the perimeter ize of lh damper IDultipli d by the equi alent length of Imetr eg an 800 mm x 400 mm duct damper hall have a surface area for casillg leakag p donnan calculated as follow (2 x 08) + (2 x 04 x I
=24m2 casing area
Other pelforlllance ancl rating test methods for damp f and valves are specified in ISO 5129 and BSIE 1751 and are referenced belm a) Leakage past a closed damper
alve BSIE 1751 b) low ratepre sure requirement
characteri t cs BSIE 1751 c) Operational torque le ring
BSEN 1751 cl) Thermal transfer testing
BSIEN 17 I e) Reg nerated sound power levels
ISO 5129
164 Installation Dampers shall be imaalled in accordance will) any re Ievant ISO EN or British Standard 10 aJ bUT lcling regulation and national code of practice as well as the manufacturers recommendations
17 FIRE DAMPERS AND INT MESCENT SLEEVES
171 General Damper or sleeves arc requiTed on duct y~telll where the designer has -tjpulated the
duct wiU penetrate a fire compartment in the majority of application tbermopla ti ductwork is ugtecl where contamlDated corro ive or otherwise exceptional fumes are concerned it is preferable to use tire damp r which are externalJy mounted ie of the intmnescent operated crush typ
24
72 Fit-e rating The damper assembly should have a fUT
resi tance ratin o equal to that of the fir ban-jer it penetrate and ball be fire tested and rated to the timetemperature curv of B 476 Part 20 and 22
173 Intumescent sleeve At the time of writing this specification qualified test results were available for rectangular dampers and circular dampers up to 55 mm diamet r Manufacture have indicated that they are able t provide speci fications for other size and diameters This infonnation should be confirmed b th de igner Various type are available includino
tho e incorporating ruechanical closing plate and those operated anI by expanded iJllUme c nt media
In all ca es fire damp rs and intnmeBcen leeves shall be supplied and in taUed in
accordance with the manufacturer iJlStructioos and COSHH a essm nt
174 Other types Fire dampers of mious types are availabl for specific purpose~ ee HVCA publication DW144 The de igner should )lot (hat materials for con lt1Jction bould be uitablc for the par1icular application
ALL C SES FIRE DAMPERS AND fNT MESCENT SL _VES SHALL HE S PPLTED AND INSTALLED IN A ORDA CE WITH Tf--IE MANUshyPACTURERS STRUCTTONS AND COSHH ASSESSMENT
18 FLEXIBLEEXPANSION dOINT CONNECTIONS
181 General ploperties Tbe material u ed for flexibleexpan ion iojnt~
mu t meet the design r requirements for temperature air pressllrelfe resistance applicable to pl astic duct sy tem vibration and noi e br akout when incorporated into a jointconnection and shall comply ith lh standard of air-tigbtne specifi cl for the duct work sy tem of which it fOlms part (See Figs 23 24 5 26 27 amp 28 for typical con truclion clelai Is
DW154 SJecilimtol for Plastics Ductwork
Expansion joints
Fig23 Moulded bellows type (rectangular and circular)
Fig24
~F aiblc sleeve
__ liding sleeve
~~~~
Sleeve type (circufar)
Fig 25
AIRFLO
COnlinuou~
weld~
Flexible Iceve
PV A HOWN pp SE BACKING FLATS AS FIG 2
Sliding lee c Co1linuou
weld
Flanged sleeve (rectangular and circular)
25
DW154 Specificatiol for Plastics Ductwork
Flexible con ections
Fig 26 Flexible sleeve with clips (UPVC and PP)
--__ Flexible I eve
I
I
I CODn clioD to plant ~
Band clip
Fig27 Welded flexible sleeve (UPVC only)
Plastic)sed PVC slceve ~-- onll11uo1sly welded
onrreclion to planl ~
Fig28 Flanged flexible connection (UPVC and P )
t sp dally moulded flexible flanged connCClitlll
boil
C)nneclion to plant ~
26
DW154 Specificotiol for Plastics Ductwork
182 LOClt1tion Flexible joint are typicltllly lIsed at building expansion joint and fan inletsoutlets Any others required should be indicated on the de ign drawings Care should be taken to maintain alignment across jointsconnections
183 Length Flexible Jomts shall be kept as short as pra middottieable above a minimum eft ctive length of SO mm In no ca e shall a flexible joint exceed 250 mm in lengtb
184 Connections to rectang a ducts With flanged rectangular connections Ule tlexible material shall be held in pLace with flat pIa tic strip of not less U1an 6 mm thick ltlttached to the flanges using uitabJe fixings The more heavy weight type of fleAible mateLial may also be obtained formed into a channel ection with corners fitted to give a neat air tight j int For pigot connections the Be ible material shall b held in place with flat pIa tic trips n t less than 6 mm thick
t 85 Connections to circular ducts With tlanged circular connections the flexibl material shall be held in place with flat plastic backing strips or proprietary clip bands with screw or toggle fast ners
186 Welded flexible connections (Rectangular and Circular) Where the parent and llexibl material are from imilar ba ed products they can be joined to the duct u ing the welding method described in Section 823
19 PROTECT VE FINISHES
191 nles otherwise stated all ductwork shall be mallllfactured in mat fial as pecified in tbis specification Any special coatingpaint fmishes to be provid d by the duct work contractor sball be advisd by th de igner
20 CONNECTIONS TO BUILDING OPENINGS
201 Fanning and finishing building op nings are not the repoJlsibjlity of the duftw( rk contractor and the note that follow are for guidance purpo e only
2011 Openings in brick block or concrete walls shall have inset frames to provide a suitable means of fixing grille louver masking flanges or the tlanged ends of ductwork The illset frames shall be conslnlcted to maintain the structural int grity of the wlll and where applicable cavities shall be suitably lined
2012 Openin s in dry linino partItIons shall have inset frames a 2011
2013 Openjngs in cladding walls and roofs shall have flaoged leevesframes to provide a suitable means of fixing a 2011
2014 Horizontal and vertical opening xposed to oLltside atmo phere hall
be provided with a suitable weathering fini h at the external face especially where profiled cladding is used
2015 Timber framed op nings are not permitted In fj re compart ment barriers
202 Ductwork connections to building openings hall have a flange of suitable profile to permit practical fixing to the openillg frame In selecting the profile consideration shall be given to Tabl~s 2 and 10 in this specitication relating to duct ize and rating Gasket strip or sealant shall be ltlpplied between the tJaoge and building op ning frame
21 DISCHARGEEXHAUST TERMINAL
21 Tbese shall be vertical open ended and designed to meet and comply with current r gularions on contaminated flue The designer hall ensure that the de ign and perf rmance i suitable for its intended purpose Examples of some typical terminal designs are SbOiD in Figbull 102 10 bull 104 amp 105
27
DW154 SpedjimioTl for Plastics Ductwork
22 THERMAL INSULATION
221 The provision and application of thermal insulation to ductwork is not the responsibility of the ductwork contractor
222 Where ductwork is required to be preshyinsulated the specification should be agreed with tbe designer
223 Where the temperature of the air within the duct promotes condensation on the exterior surface of the duct and cause moisture penetration througb the thermal insulation vapour scaling may be required and in this case the most important requirement is to limit penetration of the seal
The extent of any vapour sealing of ductwork thermal insulation and the support method to be u ed must be clearly pecitled in advance by the designer
224 For detailed information on the thermal insulation of ductwork reference should be made to BS 5422 1990 which covers the specification for thermal insulation materials on pipes ductwork and equipment (in the temperature range -40degC to +700degC) and BS 5970 1992 which is a Code of Practic for Thermal Insulation of Pipework and Equipment (in the temperature range -lOOdegC to +870degC)
23 FIRE RETARDANT FINISHES ON PLAST C DUCTWORK
231 The designer should note tbat ductwork constructed to DW154 has no teted fire rating or information see Appendix C
24 REINFORCEMENT OF DUCTS WITH GRP LAMINATE
241 General Where ductwork is required in larg T izes than are covered by Tables 2 4 6 amp 7 or with the increased strength sometimes necessary for industrial use external reinforcement is normally pwvided by applicatioD of glass fibreresin laminate
GRP systems will bond satisfactorily with standard UPVC sheet but for pp it is
nece sary to use a specially prepared sheet with a glass fabric backing incorporated dOling manufactllfe
The detailed techniques of fabrication using GRP are outside the scope of this speci lcation but the following notes are offered for guidance of ductwork fabricators
242 Materials
2421 Quality The laminate is made up of polyester resin complying with BS 3532 and glass fibre complying with BS 3496 or BS 3749 The nominal ratio of resin to glass fibre should be 7030 by weight
2422 Minimum properties The laminate shall comply with the followiog mini mum pbysical properties
Tensile strength - 70 MNm Tensile modulus - 7 Gl m Flexural strength - 140 M Im Bond strength (hetween laminate and substrate Not less than 7MNm Bmcol hardnes Not le s than manufacturers specification
The GRP reinforcement educe the expansion of the parent material but the resultant stre ses arc well within rhe strength of the bond However the Iinear thermal expansion curve shown in Figs 34 amp 35 will serve as a guide
Surface resistivity electrkal propcltles and acoustical propertie are similar to the relevanl unreinforced materials The fire retarding properties of GRP may be improved by the use of specialisl laminating resin
2423 Forms available GRP Laminate should be built up from the separate materials ie resin aod glass fibre in the form of chopped
I strand mat or spray ravings
28
DW154 Spcification for Plastics Ductwork
2424 Workshop conditions Polyester resuls are sensItIve to lmperature and the workshop hould b maintained at a temperature of herween 20deg and 25degC HiOh relative humidities and damp onditions should be avoided A good rate of air change must be pro icled pJeferably by m chanical ventilation
2425 Storage of materials Resin and urin o agents shouJd be stored in dark cool condirions away from the working area and in confonnit with statutor requireshyments for tJle middottorage of flarmnable liquid Because of Ule Limited torage lif of the unmixed resin and curing a eot mal lials ~hould be ch eked before use to enLlfe that they are within the manufacturer pe ified sh If life (usually ix month from the dm of manufacrure)
Glass fi re should be stored separately und r clean dry conditions
243 Surface preparafon
2431 UPVC To achieve the specified bond strengtll the urface to which the GRP is applied mut first be thoroughly cleaned and then etched either by mechanical means or by the use of a suitable solvent
2432 pp with glass fabric backing To achieve the specified bond middottrength the fabric backing must be thoroughly impregnated Witll resin
244 Mixing the materials for use The re in 1 a three part mix compri lng base I sin hardener and accelerator The manufactur rs pecj[ied proportions are critical and th llUxmg sequenc pecified must be meticulously foUowed
The resin has a very limited life after mixing and before u e It is dependent on the characteri tics and bulk of th resin the alllount of hardener the degree and method of acceleration and the workshop onditions
245 Methods of application
2451 General The mixed resin may be applied by hand or b pray c1epoition The operation must b completed within the gel time of th y tern and tbe laminat fully cOI1olidated to achi v the phy ieal properties pecified
2452 Hand lay-up The duct surface i coated by hand with resin Llsing a brush and a mar of gla fibp orked in until full consolidation achieved Th proc is repeated untiJ th requird thicknes i obtained
2453 Spray depo Won The duct surface is coated WiUl re in by spray gun with the chopped glass roving added through a separate nozzle The full thickne i obtain d in layer with con olidation of each layer by hand roller
246 Construction
2461 General M ini mum COllst ructional requireshyments are pe itied ill Tabl 10 for rectangular and Table 1J for circular dUClS
2462 Joints and stiffeners Fig 29 30 31 32 amp 33 hoI TOSS
joint and tiffener for reinforced UPVC and PBPP duct
247 Worki g practices The fabrication of ductwork pecifiecl ill thi document i not affected by the addition of GRP
29
DW154 SfJcdJicatiOt for Plastics Ductwork
Table 10 Minimum constructional requirements shy
Longer Side Minimum Sheet Thicknes and
GRP Reinforcement
UPVC FBIPP 1 2 3
mm mm mm Up to 1000 3 plus 3 plus
06 kgm2 06 kgOIl GRP GRP
1001 to 2250 45 plus 3 plus 06 kgm 12 kgm
GRP GRP
2251 to 3000 45 plus 6 plus 12 kgm 12 kgm
GRP GRP
Cross Joints
UPVCFBPP 4
mm socket amp spigot
as Fig 30 or flanged as Fig 29
75 x 9 flange welded on both sides as Fig 29
75 x 9 tlange welded on both sides as Fig 29
rectangular GRP reinforced ducts
SlifTeners Maximum Spacing Between
JointsSljffeners UPVCIFBIPP UPVCFBPP
5 6 mm mm
75 x 9 flat 800 as Fig 31 or
50 x 50 x 5 plastic or MS inverted angle as Fig 32
or tormer as Fig 33
75 x 9 flat 600 as Fig 31 or
50 x 50 x 5 plastic or MS inverted angle as Fig 32
or former as Fig 33
75 x 9 flat 600+shyas Fig 31 or 50 x 50 x 5 plastic
or MS inverted angle as Fig 32
or former as Fig 33
Note 1 On rectangular duct up to 400 mm longer side no stiffeners are required 2 Applies to Tables 10 amp I I For COlJstructional operating temperature limits refer to Part 2 clause 5A 3 Tables 10 amp II apply to all pres ure classes up lo ]500 Pa
Table 11
Diameter
1 III
lJp to 1000
1001 to 1750
1751 to 2500
Minimum Sheet Thickness and
GRP Reinforcement
UPVC FBPP 2 3
mm mm 3 plus 3 plus
06 kgm 06 kgm GRP GRP
45 plus 3 plus 06 kgm2 18 kgm
GRP GRP
6 plus 6 plus 12 kglm2 18 kgm1
GRP GRP
Cross Joints
UPVCFBPP 4 III
socket amp spigot as Fig 30 or flaoged as Fig 29
75 x 9 flange welded on both sides as Fig 29
75 x 9 flange welded 00
both sides as Fi 29
inforced ducts
Maximum Spacing Between
JointsStiffeners UPVCIFBPP
6 mm 2400
800
600
Stiffencrs
UPVCFBPP 5
mm 50 x 9 flat as Fig 31
75 x 9 flat as Fig 31 or former as Fig 33 75 x 9 tlat as Fig 31 or t()rmer as Fi 33
ote On extruded tube tip to 600mm diameter no stiffenergt are required
30
DW154 Specificatioll for Plastics Ductwork
G - Cross joints and tiffeners
Fig 29 Flange Joint Fig32 Stiffener shy inverted angle
M artiPfCuQkbdd erttpObri) Wl111 RP tlddtlt
_- GRPloliu] lh~
Fig 30 Socket and spigot joint Fig33 Stiffener shy use of former
Fig 31 Stiffener Flat
I Pv FlPP ~ ~lmJaDUA1) d
OMrlQ rrnall 1( tQlS
25 STANDARD COMPONENT DRAWINGS AND ABBREVIATIONS
251 The illustrations in this section not only highlight where applicable geometric limjtations for the de ign and manufacture or ductwork components but also recommend
standard drawing representation terminology and abbreviations for both duetwork components and some of the more commonly used ancillaryplant items
252 Designers and surveyors should note that bills of quantities should provide a full description
3)
---
v
DW154 Spcc(fim(ml for Plastics Ductwork
Fig 34 Linear Thermal Expansion
u c 0 N ro 0)
b 0)
S
sect0
5 oS cl) 0)
~
on ~ ltl
c U
-30 -20 -10 0 10 20 30 40 50 60 70 80 90 TEMPRATURE C
~ V
-
~~c_ ~
~V
V ~
-7 ~
-- ~V ----
v
-6
+14
+12
+10
+8
+6
+4
+2
0
-2
--4
ig 35 Typical Design Stress tor UPVC and P
7
6
r shy 5E
-c E----0 4t) VJ 0)
ci5 0Jl 3
~
0)
Cl
2
1
o
UPVC
1
000
1
1
pp
- r-- shy r----- shy - t--shy I
__0
-30 -20 -10 0 10 20 30 40 50 60 70 80 90 TEMPERATURE C C
Note Figso 14 amp 35 shaded area refers to GRP reinforced duct
32
DW154 Speciicfltirm for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - REC ~NGULAR
Splilt~r Posilion W-mm pliucr
A B c 40]--QOO 1 W - -
601-1000 1 W4 Wf2 -
1001-1800 3 WI W3 W2
FIG DRAWING DETAfiS
tU]36 ATI Straight Duct with socket and spigol joint
rn [037 Straight Duct with flanged joints
[I []38 Straight Duct with flanged joints
rkJ Short Radius Bend
39 Applies to any augl and for duct up to 400 n11n wide
Minimum (I1m31 radills = 100 mm
Medium Radius Bend (a illustrated)
[kJ Applies to any angle
40 Long Radiu Bend Similar but radius = W
Throlll radius = W2 Applies to any angle
- Short Radius Bend with plitlers
I -shy -shy u co - t lt Li--_ 41 t 0 ~ I I I
~ I
L 1W
Minimum waal radius = 100 mm Splitters not required in bend angle less than 45deg
42 QJ1 Square Bend with turning vanes ij
3
DW154 SP(L~ficatioll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - RECTANGULAR
FIG DRAWl G DETADS
43
~
I v
L L Radius Tee with internal deflectors
44
~ Radiussed Twin Bend
45
Imiddot
er Swept Branch
46 U-
Sqoare Tee with Turning Vanes
47
~ f
Breeches Piece
48 0 y l Piece
34
DW154 Specificatioll for Plastics Ductwork
STANDARD COMPONENT RAWINGS - ECTANGULAR
55
54
51
50
53
52
49
FIG
~MX
RAWlNG
DmiddotMAX
EfjMAX
Minimum throat rndius = 100 mm
Rectangular shy Round Transformatioll
Eccentric Taper 225deg max in either plane Spliller are required for angles greater than 225deg and hould bi eet the angle between any side and duct centreline
DETATLS
Angled Offset
OUset Taper Splitters are required for angle greater than 22 0
and shoold bi eet the angl between any side and dUCI centrelinc
Mitred Offset
Concentrk Taper 2250 max in ither plane SpUtters are required for angle greater than 225deg and should bisect the angle between any side and duel c ntreline
Radiussed Offset
35
DW154 Splcilcuthm for Plastics Ductwork
STANDARD COMPONENT DRAWINGS ~ RECTANGU AR
Branch ducl DimCllsions widlh (W) (A)
urnl mm up lO 200 75
300 100 400 125 600 150
Ocr 600 200
FIG DRAWlNG DETAILS
56 poundplusmni~~ Rectan~lar - Flat Oval Transformation
57 [ Square Branch
58 er Angled Branch
Branch dUCI Dimensions wfdth (W) (A)
[- mm mm59 3shy Shoe Branch Up (0 200 75
--shy AIshy + 300 100
400 125
450 MAX 600 150
Over 600 200
Branch duct DimensIOn
rP X width (W) A)
60 - 1--shy _
~ mm mm
Bell Mouth Branch pto 200 75 300 100 t 400 125
600 150 Over 600 200
0=0 61 -
~ Bell Mouth
- shy T 4-5deg M x
--I 1-shy
TJ
62 X I ] I
Tele-scopic Joint I Illustrated with flangeL
X63
SBD Single Bladed Damper
36
---
DW154 Spedicatioll for Plastics Ductwork
STANDARD OMPONENT DRAWINGS - RECTANGULAR
DRAWING DETAILSFIG
64 on-Return DamperNRD shyshy
shyXbull
Multi-Leaf Damper Can be piggoted or flanged oppo cd or parallel blade
Alternative controls areshy
q p [gtshy
J HD65 Hand
~MD otori ed
PO Pneumalic
L-lt
l 13G 66 Blast Gate DamperX X
FireSmoke DampersSleeves
211r Ratinggtshy----
L_-
---
----
r----
Ir-- shy
IL- _-l
2hr
With i tallation frame
67 41 r Rating
4hr
Smoke damper SD
Intumc cent Sleeve L-d
37
DW154 Specijicutiolt for Plastics Ductwork
FIG
68
69
70
71
STANDARD COMPONET DRAWINGS shy REC ANGULAR
DRAVING DETAILS
gtshy Access Openings
AP 6 Access Panel - Rerno able
w [ ~ Access Door - Hinged
I ~le Inspection Cover
le -I reg -lt
~X X Flexible Connection
~ Drop Cheeked Radiussed Twin Bend
U Drop Cheek Bend
I
72 Air Flow SymbolX
38
DW154 Specifim[ioll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - ECTANGULAR
FIG DRAWING DETAILS
73
74
75
76
77
Q
Q
rp---t
~
V- I Ir---I
JL --11
THE ABOVE DETAILS TYPICAL PLENUM
Air Terminal Plenums
Plenum with side connection
Plenum with top connection
Cover plate with connection
Special plenum with connection
elescopic conn ction in direction of air flow
39
DW154 SpecijicotiOll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG
78
79
80
81
DRAWING
-23~---pound3-(MALE) (FEMAJE)
-t=j--_j(--d-shy
--L
~ THROAT RADI S= D AS T NDARD
e ~
THROAT Rjf)lU = D A MU)
DETAILS
Straight Duct With male and female connectors
Straight Duct With flange joint and slip joint
Bend MouldedIFormed Applies to any angle ego 30deg45deg60deg90deg Medium radius bend as illustrated Long radius similar but throat radius 0
Segmented Bend 90deg four section minjmum as illustrated
Other Angles 60deg = 3 sections 45deg = 3 sections 30deg = 2 sections
I
i
40 shy
DW154 Speciicafinll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG DRAWING DETAlLS
82 Segmented Twin Bend Radius = D2 max
May also be fabricated from tube
83 Equal Tee MouldedIFormed
84 -~ 1in Bend MouldedIFormed
85 Taper Concentric 1 0 as iUu trated Eccentric 30deg iJJcLuded angle
86 Short Taper
41
DW154 SpcUicatol1 for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG DRAWING DETAILS
87 30 max Offset
Angle Branch
Bran h dUCI Dimcnsions dia (D) lA)
Shoe Branch mm mm 88 Cl
Off rectanguJur Up 10 200 75 lOO 10 400 125
- 00 150 Over 600 200
Bl1IllCh duct DimenlOns din (D) (A
~-$a-Conical Branch mm mm
89 Also acceptable with Up 10 200 r
full conical surface 300 10
400 125
END VrE -shy 600 150 Over 600 200
90
m 75
100 12 150 200
mm Up to 200
_ 300 400
600 Over 600
iUtred Branch
Shoe Branch
J-L----U ~ Bell oulh Branch
ENDV1EW
93
92
91
42
DW154 Specificatiol for Plastics Ductwork
STANDARD OMPONENT DRAWINGS - CIRCULAR
FIG
94
DRAW G
I
~ 30deg 090deg
Breeches Piece
DETAILS
95 amp-----~ Blank End
~-----p Multi-Leaf Damper Can be piggolcd or fianged opposed or parallel blade
Alternative controls areshyri=-+- L-T~
I
---
LT~
I r- -
-+1
J HO Hand96
bMD Molori cd
PD Pneumatic
tl-shy bull
Single Bladed Damper 97 ~ saD
on-Return Damper Vertical application only 98 m~D
43
DW154 Sf1tcificatioll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG
99
100
101
102
DRAWING
$ I-
2hr
1 4hr
SD
~v I I
CO TINENTAL COWL
DETAILS
Iris Damper
Fi reS moke Dam persSleeves
2hr Ratillg
With installation frame
4br Rating
Smoke damper
Intumescent Sleeve
Access Openings
Access panel - removable
Access door shy hinged
fnspection cover
Discharge Continental Cowl
44
DW154 Sp(Cii(ltJll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
DRAWINGltIC DETAns
-
I
I
~
I I I High Velocity Discharge Terminal 103 I
I
I I
J I I 1 ~--
Offset Stack Discbarge Terminal 104 1
~ I e --(-
I
N
I
I
I~
I I Vertical Oischarge with Weather Cowl 105 I
--1--1 I
I
GAPI I
RTl AL DISC) lARGE WITH W ATIIER COWL
45
DW154 SpecUicatoll for Plastics Ductwork
STANDARD COMPONE T DRAWINGS - PLA TEQUIPMENTIMISCELLANEOU
FIG DRAWING DETAILS
106 ~~~ Rectangular Attenuator
107 ~- Circular Attenuator
108
~ Beod Attenuator
109 J ~(f) Heating Coil
110 J ftte Cooling Coil
III Jc[ Electric Heating Coil
112 X F
Humidifier
113 [H XX Axial Fan
114 ~fB1famp Noo-standard Ductwork Cross hntchillg (of any separate type) indicates by reference to a key any non DVil54 ductwork system
115 2llIIIIJIIIIIll Flexible Ductwork
46
DW154 SJeCUicll(iol1 for Plastics Ductwork
TABLE 12 - STANDARD ABBREVIAT ONS
ABBREVIATION FLL
AD Acces Door
AFF Axial Flow Fan
AHU Air Handling nit
All Aluminium
AP Acess Panel
AT Attenuator
AV Air enninal Unit
BE 81ank nd
BQ Blast ate Damper
CC Cooling Coil
CF Centrifugal Fan
CTA Cross alk Attenuator
CVU Constant Volume Unit
DP Drain Point
EEC Electric Heating Coil
El Expansion Joint
FAl Fresh Air Inlet
FA From Above
FB From Belo
fBPP Fabric Backed Polypropyl-ne Sheet
Flexle Flexible Connection
lexfD Flexible Du t
C False Ceiling CO an oil Unit
fD Fire Damper
FFL Finished Floor Level
FJ Flanged Joint
FOAM Rigid Polyurethane Self xtinguishing Foam
FOB Flat on Bottom
FOT Flat on Top
GAM Galvanised after ManufacttrJc
GRP Glass Reinforced Plastic
GSS Galvanised Sheet Steel
HC Heating oil
HD and controlled Damper
HH Hand Hole
HL High Level
HVD High Velocity Discharge
IC Inspection Cover
ID lri Damper
IFS Intumescent Fircleevc
47
DW154 Specification for Plastics Ductwork
TABLE 12 - STANDAR ABBREVIATION CONTINUED
ABBREVIATION
IU
L
tv1D
MS
NRD NTS
OBO
OE
PHD
PD
PP
PP
PRD
PVC
RFC
RSC
R
SBO
SO
S1 TST
SSL
TA
TB
TO TJ
TP
TV
TV
OS
UPVC
S
V
VAV
50 RSA
FULL
Induction Unit
Low Level
Motor controlled Damper
Mjld Steel
on Return Damper
at to cale
Opposed Blade Damper
Open End
Parallel Blade Damper
Pneumatic controlled Damper
Polypropylene
Self xtinguishing Polypropylene
Pressure Relief Damper
Polyvinyl Chloride
Rolled Form Chamlel
Rolled Steel Channel
R fUnit
Singl Blade Damper
Smoke Damper
Slip Joint
Stainl t el
tructural Slab Level
To Ab vc
To Blow
Top Down (In Direction of Flow)
Telescopic Joint
Test Point
TU111iog Vane
Top Up (In Direction of Flo )
Voles Otherwise Stated
Unpl3sticisecl Polyvinyl Chloride
Underside
Ultra Violet Light
Variable Air Volume
Rolled Steel Angle (Vith Size)
48
DW154 SJeriiflllioll for Plastics Ductwork
A2 DUCT PRESSUREAPPE DXA Ductwork con truct d to DWIl54 will bebullbullbullbullbullbullbullbullbullbullbullbullbullbull
Air Leakage From Ductwork To be read in conjunction with DW143 A practical guide to Ductwork Leakage Testing
CAUTION As highlighted ill both this docul1lenr and DW14 I lot ellough emphasis can be placed 01 the fact that except for high pressure class C the much more stringent ductwork constructional standard brolght about b the general acceptance of DW154 have irtlally negated the requirement for leakage-testing It is essential lO realise lhat except where it is mandatory this doclllllelll is nOl an endors ~lIlent of the rourine testing of ducts bllt purely a guide to outline the procedures for cononnity with the air leakage limits ill Table l Where the specified methods of assembly and
A3sealing of dlcls are u ed a vi ual inspection wil ordinarily sl~fll e for ver(iatioll of a well engineered and a ceptahfy airtight COl1strucrioll WHERE NOT MANDATORY DUCT LEAKAGE TESTING IS GENERALLY AN UNJUSTIFIED AND SUBSTANTIAL EXPENSE
A1 INTRODUCTION L akage from ducted air distribution systems is an Lmportant consideration in the design and operation of ventilatjon and air conditioning middotystems A ductviork t)ystem tbat ba limited air leakag within defiucd limits wiH cnsUft
that tile design characteristics of the sytem can be maintained It wilJ also ensure that energy and operatLonal cosb are maintained at optimum levels DucLwork constlucted and Ulstalled in accordance with DW154 should minimise a level of air leakage that it) appropriate to tll operating static air pre sur in tile system
A4However it is recouuised that tbe environment in wtJich middotystems are installed is not always conducive to achieving a predictable level of quality in term of system ajr leakage and it is therefore accepted that designer may sometimes require tlle ystem to be tested in part or in total It should be ecogni ed that the testing of duct systems add a ignificant cost to the installation and incur some extra tjm within the programme (Se 47 and 64 re mandatory te-sting)
manufactured to a structural standard that is compatible with the system operating pressure There are three classes of duct con truction to eorre pond with the three pre ure clas meations Class A Lo pressure ducts suita le for a maximum positive operating pressure of 500 Pascal and a maximum negative pressure of -500 Pascals Class B IVledium pressure ductmiddot suitable for a rnaxilnuJJl positive operafjn o pressure of 1000 Pascals and a maxllnum negative pre sure of -750 Pa cal Class C High pre sure ducts suitable for a maximum po ilive operating pressur of 2000 Pa cals and a maximum negativ pres ur of -750 Paltcals
LEAKAGE FROM DUCTWORK Leakao-e front pia tic air ducts occur at the joint~ and is therefore proportional to the total surface area orthe du twork in th system Tb level of leakage i imilarly related to tIle air pres ure in th du t system and whilst there LS n precis formula for calculating the level of air los it i generally accepted that leakage will increase in proportjon to pressure to rbe pOvver of 065 The effect of air leakage from high pressure velocit ductwork is critical tn terms of system perfomlan dege energy consumption and the risk of high frequency noise as ociated with leakage These problems are le critical with medium pressure 10 ity systems but should be con idered Low pres mevelocity ducts present the lowe~t
ri k in tenn of tbe effect of leakage on the operation of the s stern
SYSTEM LEAKAGE LOSS As there i no di ct relatLonship between th volume of air conv yed and the surface area f the ductwork sy tern required to match the building configuratmn it is difficult to express air leakage a a percentage of total air volume Similarly the operating pressure will vary throughollt lh 3 system and a leakage is related to pre me the calculations ar comple However it is generally ac epted tbat in typical good quaJjty systems the leakage from
49
DW154 Specificatioll for Plastics Ductwork
each class of duct llnd r operating condition will be io the region of CIa S A low pressure 6 Clas B medium pres un 3 Clas C high pressure 2
A5 SPECIFYING AIR LEAKAGE TESTING Re peeting both the co -t and programme implications a sociated with te ling du 1 for leakage the designer may for example indicate that a particular system is te ted as follow
a) High pressure ducts - all tested b) Medium pr ssure duets - 10 of the
ductwork shall be s eet d at random and tested
c) Low pre sure - unte ed In any case where a random te t i elected for medium pre sure ductmiddot the followin c1au~e is suggested for inclusion by the de ign r
The designer hall elect at random a maxirnwlI of 10 of the dUCl system to bt tested for air leakage The duct hall be tested af the pressure recommended in Table J3 for the assifi atiol for the ectiol1 of the ductwork that is to be tested The tests shall be carried Ollt as the work proceeds and prior to the application of thermal insulation In the event of test failure of the randomlY selected section the designer shall have The right to select two La1her e tiolls at random for resting Where succes ive failures are identified there shall be a Tight to require rhl COl11raCWr 10 apply remedial attention to the complete ductwork system Th contractor shall provide documented eviden e of the calculalions used to arrive (1
the allowable 10 I for the section to be tested and the client or his agent shall willess and sign the results of the test
able 13 Air leakage rates
Maximum leakage of duct work Static
prcssUft Low-pressure edium-prc-sure I Iigh-prebull me diJfercntial Class A Class B Class C
1 2 J 4 Pa Litres per second per quare metre of surface area 100 054 018 ZOO 084 028 300 110 037 400 132 044 500 153 051 600 058 019 700 064 021 800 069 023 900 075 025
1000 080 027 1100 1200 1300 1400 1500
029 030 032 033 035
1600 1700 1800 1900 2000
036 038 039 040 042
Note Recommend d mean test presures are highlighted iD bold type with the actual selection being left to tll test operator
50
DW154 Sfeeiieaioll for Plastics Ductwork
A9
A10
and air leakage classification for the y em under test
DESIGNERS CALCULATIONS The designer can middotaJculate with reasonable accuracy the predicted total loss from a ystem by
a) Calculating the operatin presure in each ection of the sy tern
b) Calculating the surface area of the ductwork in each correspondin pre lire s ction
c) Calulating the allowabl~ los at the operating pressure for each ection of the system (see table 13 for allowable leakage figures)
VARIABLE PRESSUR S IN SYSTEMS De igner can achieve significant co t saving by matchina operating pressures throughout the system to constmctional standard and appropriate air leakage testing eO the practice of specifying construction tandards for whole duct sy tems based on fan discharge pre sure may incur unnece sary costs on a project For example ome large sy terns ould well be classiC ed for I akage limits as follows
Plant room risers CJas C Main floor distriblltJou CIa B Low pre sure outlets Cla A
A6 SPECIAL CASES There may be ~itLlations on a project where circumstance dictate thal pecial consideration be given to containing air loss s eg a long mn of duclwork may incur a di -proportjonate level of air 10 s In ca es such as thi example the designer can specify an improved tandard of airtighmess ie 80 of alJo~able 10 s for la B Ju ts The designer sbould not specif a CIa C t sI at CIa s C pressure for a CIa s B ducl
A7 SUGG S ED RANGE OF TES ING
A8 TESTING OF PLANT ITEMS Items of inline pJant (eg Fig 106 to 115) will not normaUy be included in an air I akage test The dllctwork contractor may indud such itelllS in tbe te t jf rh quipm ot has a certificate of COnfOlnlity for Ihe pres ure clas
bull High pressure duct bull Medium pre sure ducts bull Low pre sur ducts bull Exposed extract syst ID bull Ceiling void extract
systems bull Secondary ducts from
VAV or fan coil units bull Flexjble duct bull Final connections and
branches to grille and diffusers
100 test See A5 Untested UDt sted
Untested
Untested Untested
Untested
SI
i
DW154 SJecijicafion for Plastics Ductwork
ig 116 Permitted leakage at various pressures
Leakage in litres per second per square metre duct surface area
Vgt
o ltgt 0 ltgt N
ltgt Cgt
0 0 cc
0 0
~
g =
g ~
c 0
J
ltgt 0 I
~ ] tn
ltgt ltgt
In ol
~ 0 ~ 8 ~
~
c ltgt ltgt
~ CJ
~ ~ ~ ~ 8
0shyij
~ ~ ~ t
ltgt ltgt 00
l
~
~ Q
c C
~ rshy
e ltgt
I 1
I Cgt ltgtv
c Co ~
~~ ~ 10
I
0 Cgt
fJshyq 410 ) 1 ltgt
ltgt N
~ shy ltgt ltgt
~ I 1
c
52
DW154 Specificatio for Plastics Ductwork
Example of a completed test sheet Test No
General
Name of job N~ jC43Pt(r2lef Building Repound ~(~~0
Part 1 - Physical details
a Section of duct work to be tested ~(diffPIfff~el1f3rd Floor
b Drawing Number g91~~ c ssure aSSJ L atlOn V~Jl~IRfYgtg~~lPre Cl T Class C
d Test static pressure -(9 raErq~ ~~~~-~~J~~~ ~~ ~~~~ll
Leakaoe factor 9~-tre3$ecMz I OM REFTOTABLE 13)e b bullbullbullbullbullbullbull
f Surface area of duct under test Q~tJJItetre$ CPROMCALCU TIO BELOW)bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull ampampamp bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull
g ]Vlaxi mum permitted leakage -~ (~i~~0 ~~r~~ ~~~l-~-11~ ~~~Q
Part 2 - Test particulars
a Duct static pressure reading 9QFt~q~ ~ middot~~~1 ~~
b Manufacturer and type of liow measuring d vice (-~~~cJ~Y-9Q7EYg c Range of measurement of now measuring device QtP)OQ~(e~~~0I~~~~1~I~ ~~~~~~W~
d Reading of flm measurin o device pmiddot IFROM RIO)ftscag ~
I (DERlVED [ROM CHART SUPPUED WITH RIG US 0 ud)1e Interpreted air flow leakage rate ~(~~~f~~~ (~l~~~~~~~~~~~~~~~~~I
f Duration ~~~~~norn~allY l~ lnil1Ut~~d~~~ it1~ W~ Date of test ~(lITled ut by Wltll s ed by ~ ~
(~lJ MIJLrr) (Si~rrfltJUYJ
Printed Name 1~g0f~ Printed Name ~~Y~9~ and Company 7jl~~~~~( UJd CompanY AB COII$Itallt8
Width and depth or diameter
Periphery ength Area
millimetreS millimetres metre qL1are metre
800 x 750 3100 1755 5440
600 x 650 2500 557 1193
300 x 300 1200 120 144
305 din 958 700 670
250 dia 785 450 353
TOTAL 8000
53
DW154 Specijilarion for Plastics Ductwork
pA XB
Guida ce No es For he ransport Handling and
Storage of uctwork
avoid damage to adjacent duct panels In somc ca es particularly on con acts calling f r repetitive sizes the use of timber jigs and spacers may be justified Where reduced bulk and greater protection are major factor such as consignments for export transporting ductwork in L shape sections may justify the increa ed ite as embly co ts
It is recommended that before a contract is finalised that consideration is given to the subject of site acces material handling and storage as tbcy havgt a strong influence on the cost efficiency of the overall activity of ductwOlk installation
B3 Handling To minilnise th risk of damage duct sections should be clearly identified and deliveries to site should be closely linked to the installation programme so as to avoid accumulation of
B1 Storage and Handling of Ra Material Material should be stored in suitably designed racking out of direct unJight Where possible the e racks should be metal to earth Edges of cut she t may be harp and protective gloves are advised Wearing teel toe-capped boots is recommended Most pIa tic sheet is manufactured with smootb mfaces andor is suppLied with protective coating Care must be taken to prevent accidental lippag of stacked materials Beiuoshy good electrical insulators the movement of stock unless earthed will allow the build up of stati All stock shapes are chemically stable at normal temperature Whil t some raw materials used in their manufacture may themselves pre ent a toxic hazard once incorporated into the lOck bape they no long r constitute such a hazard and no dermatitic bazard are known nor are any
unfiJied ductwork and minimise double handling It is important to recognise that ductwork panels joint and corners arc susceptible to damage and care must be taken wheu band ling such material through a site During handling individual item of duct work may be liable to light cross sectional deformation until thev become an integral pan of a completed ductwork system Whilst this may temporarily detract from its intended appearance thi deformation will not have any detrimental effect on the functionality of the finally a semblecl system Installation of duct work and asociated plant items ill illevitably involve manual handUng The responsibi Iiry of employers and employees to a ses the risk of personal injury during mallual handling operations is et out in the HS E publication L23 Guidance on Manual Handling Regulations 1992
environmental problems expected 84 Site storage
B2 fransport Large capacity vehicles with high-sided open or closed-top bodies are tlle mo t suitable for the transport of dllctwork Careful consideration should be given to the
Adequate floor space IDust be provided within tbe building for the site storage of ductvork Such storage shalt make due allowance for thc stOf(ne of ductwork in stacks such that access ~ egt
between them is of sufficient width to pennil the removal of item without interference to
unloading of transport on sit a not all siJes b n fit from the material handlino- and access facilities that exi [ in a manufacturing workshop such as crane- fork-lifts or loading bay Site handJiog facilities along with
adjoining sta ks Ductvork components should be positioned so a to avoid crushing Ductwork of small panel size may be stored horizontally however care should be exercised to ensure that tack sizes are limited 10 within
ehicular acce s restrictions may itilluence the type and ize of transport to be uWised
engtlls of ductwork should be positioned 0
the tmctural strength of the duct sections to prevent distortion of the lower sections within the stack
as to avoid crushing Lengths Witll projections such as branches and bends i1anges girths damper quadrauL should be loaded so as to
54
DW154 S1tciic(ltioll for Plastics Ductwork
85 Internal cleanliness of new ductwork The site storage of ductwork introduces the important cODsideration of maintaining the internal cleanliness of the ductwork R feren e should be made to HVCA documentshybull DWffM2 Guide to Good Practice - internal
Cleanliness of New Ductwork Installations If the above conditioDs can not be satisfied consideration should be given by tJle designer to amending the specification to include for Po t Installation Cleaning as covered by tJ1C HVCA documentshybull TRJ17 Guide to Good Practic - Cleanliness
of Ventilation Systems
APPE DIXC
Fi e Retardant inishes C1 Improvement in the fire retardancy of plastic
ducts can be achieved to varying degrees and is wholly dependent llPOll the surface coating laminating resin selected and construction specification adopted In some instances smoke emission is coILSidered equaUy with other speci fication requirernen ts of the materials resistance to ignition and bumjng It is therefore important for design rs to establ ish the clients and officers detailed requirements and not rely on a tbird party interpretation of fire resisting or fire retardant Where possible the specification should refer dir etly to compliance with a British or European Standard identifying the specific sections applicable There are various types of resin and mat rcLnforcements that can achieve a Class 1 surface spread of flame ratin o when tested according to BS476 Part 7 (1987) This test puts materials illto Class I - 4 in descending order of perfoDllance according to the rat and extent of flame spread over their surfac under standard beating conditions Materials should also be tested for flre propagarion to BS476 Part 6 (1989) Tbi tesr measures the amount and rate of heat evolved by the material when subjected to standard heating
conditions Test results are given as an index of Perfonnance (i) whicb is based on three sub indices (iJ (i1) (h) The higher the value of the Index of Performance (i) the greater is the material s contribution to fire growth The higher the value of the sub-index 0) rhe greater the ease of ignition aod flame spread The highest product performance classification as defined in Approved Document B of the Building Regulations is Class O This is acLlieved if a material surface of a composite ploduct i~ either a) composed throughout of materials of
limited combustibility or b) a Class I material which has a tlre
propagation index (i) of not more than 12 and sub-index (i l ) of nor more than 6
01 J Class 0 is not a cla$sif1cation identified in any British Standard test
There are resin system reported to be classified to Class O when tested to BS476 Pcl1S 6 and 7 however designers need to ensure that such sysrems can be applied to their proposed design In propriety resinmat system available the fabrication techniques and COITect application are critical to the integrity of the reinforcing and clas ificatiol1 For example in some systems the u e of a non-fire retardant gelcont on a fire retardant substrate would reduce the classification For further information see HVCA publication DW144 Appendix D
55
DW154 SplCijiClIliol1 for Plastics Ductwork
x Guidance otes For nspectmiddoton Servicing a d
Clean-ng Access Openings
D1 GE ERAL This appendix highlight in ummary fOI111
the acce considerations that hould be made by the design r iD terms of inspection servicing and cleaning Having considered the seop and the design of the dUCI work system relative to the guidelines outlined below the designer should clearly indicate which levels of acces should be incorporated into the manufacture of a new duct work system (See Table 14 and Note I b low it
D2 DESIGN CONSIDERATIONS
D21 In ptction and servicing requireshyments are set out in Section 15 of Lhis specification
D22 Cleaning requirements are set out in the HVCA pubUcation TRl7 Guide to Good Practice Clean Lines of Ventilation Systems and the guide tates The precise location ize and
type of access would be dependent on the type of ductwork cleaning inspection and te ting metbods to b adopted Care protection and standards of cleanliness prior LO cOlllmisionin o
are set out in th AV A publication DWITM2 Guide to Good Practice Internal Cleanliness of New Ductwork Installations and th guide state Wh re specific limits of cleanliness are required ductwork sball be cleaned after installation by a spcialist cleaning contractor It will b in the interests of tht desioner botb financially and practically to cunsider employing a specialist c1eauing contractor at tbe
outset of a contract to internally clean newly installed ductwork prior to bandover This approach would reali e the following benefit shyi) Tb actual numb r of cleaning
access panels could be detennined to suit the method of cleaning to be adopted (This may be 1 s than the maximum requiremen listed under Lev 13 of Table 14)
ii) Clear directions could b given to the ductwork contractor as to tJle size and location of cleaning access panels that are required to be fitted during the mauushyfaclunng pro s
iii) The specialist cleaning operation prior to commi ioning vould enable the cleaning contractor to verify the practical acee requirement for the future cleaning operation associated -vitb a regular maintenance programme
iv) A specialist cleaning operation prior to commissioning would allow the designer to omit from the speeilicatiolJ the DWrrM2 requirem nt for factory sealing protection wipe downs and capping-off
v) Specialist Ieall ill 0 to the measurable standard defin d in TR17 will allow an objective definition of cleanline to be achieved
Car ful consideration must be gIven by the designer to the practl aJ problems associated witb the manufacture and fitting of suitably si Led access panel on small cross section duct and on the circular faces of rouod and flat oval ducts in particular
D23 Special con ideration must be given by the de igner to the practical problems associated with gaining personnel access to heavily congested ceiling areas and multi-la red du twork systems This approach would avoid
56
DW154 Spfciication for Plastics Ductwork
the possibility of access panels being D3 ACCESS 0 IN-LINE EQUIPMENT incorporated into a ductwork system at the This appendix unly covers acc il1spection manufacturing stage that were later found in through the ductwork body adjacent to an item practice to be inaccessible for either ervicing of in-line equipment and not openings in the or cleaning activities equipment itself
able 14 Acce requirements for inspection servicing and cleaning
HVCA PUBLICATIO REFE NeE (uidtgt 10 Gund Prartict
Adjace t OW144 Cleanliness orVcnlillltio S~lcr~ fRjJ7
in-line LeyeJ 1 Level 2 Level 3 ite sequipment pcdionSen lcin~ Section d C1eaniJl( SUn(O)lnspc lion Palle ltk~m_n
2011 (minimum OiL Jubje-ct to duct ~zel (ft~ -Panels
Control Da pcrs One (inspection) 203 One 300 mm x 200 mm Both sid Fire Dampers One (sCTjdJl~) 20211 One 300 0101 x 200 mm One side HeatingCooling Coils One (inspedion) 20213 One 300 mm x 200 mm (lIpstream) Both sides Attenuators (rectangular) None required One 300 mm x 200 mm (downstream) Both sides Attenuators (circular) one retluired One 300 mm x 200 mm (downstream) One side Filter Sections One (inspection) 20212 one required Uoth sides Air Turn Vanes None requjred None required Both sides Changes of Direction None required one required One side In-Duct FansDevices One (inspection) 20213 None required Both sides l
1 In the absence of any indication by the designer only Level ) access will be jncorporated into a new ductwork system
2 Tbe panel izes associated with Lev lis I and 3 acee s ar e middottablished by reference to Section 20 of DW144 and Section 2 ofTRll7 respectively
57
DW154 Speclfifatio for Plastics Ductwork
pA XE
B-bliography Included in this Bibliography are technical pUblications which may be of interest (0 ductwork designers fabricators and erectors and to tho e in the heating ventilatlng air conditioning industries generally nquiric should be made of the relevant organisation at the address quoted Since its publication other addresse contained within 0V154 mav have changed and some pubJicalions may have been superseded
HEATING AND VENTILATING CONTRACTORS ASSOCIATION
4 Palace Court London W2 4JG Telephone 020-7229 2488 Fax 020-7727 9268
Orders fo FlY A Publications Old Matlsion House Eamont Bridge Penrith Cumbria CA 10 2BX (Telephone 01768 864771 Fax 01768 86718) Email hvcapoblicationshvwelfarecouk DWn 44 pe ilicatiun for sheet mctal duclwork (Iow- mediulllshy
and high-pressure) 1998) DWIl4 A practical guide to dUGI ork I akage te ting
(revised 2000) DWII54 Specification for plastic~ duct rk DW171 Guide to good Practice for kitchen venlibtion system DW191 Guide to good pracuce glass fibre ductwoJk DwrrMI Acceptance cheme for new products - Redangolar cro
joint classification Guide to good pra tice - Internal cleanliness of new ductwork installations Guide to good practice for the design for the Installation of lire and smoke uampers
J 1Other puhlications
HampV safely guide 5th edition JS2 Tool box talks JS5 Weldlng Safety booklet JSI9 afety facts bo klet Fact sheets 1-24 2nd edition JS2J COSHH manual volume 1 Advice on compliance with the
regulations 1521A CO I-rH manual volume 2 Asses mcnt h ets JS23 Ri k management manual TR3 BrazinltT and bronze welding of copper pipework cUld sheet
(I 976) TR5 Welding of carbon steel pipework (1980)
TR6 Guide to Good Practice for Site Pre sure Testing of Pipework (19 0) Guide to good practice cleanliness of ventilation Ylem
CHARTERED IN TITUTlO OF BUILDING SERVICES E G EERS Delta House 222 Balham High Road London SW12 9BS rTelephone 020-8675 5211 Fax 020-8675 5449) CIBSE Guide Volume A Design Data Volume B In tallatiol1 and quipment Data Volume C Reference Data
CommlssioniJIg Codes These Codes eover the preliminary checkS eUing to work and regulation of vanous catcgories 0 plan The Codes give a guide to design implications Series A Air Distnbution Systems Series B Boiler Plant
ri s C Automatic Conlrol ystems Cr1es R Refrigerating Sy terns
Sene iN Water Distribution Systems
Technkal Memonllda TM 4 Design Notes for the Middle East TM bull Design otes for Ductwork TM 13 Minimi iog lhc Risk of egiounaires Disease
Research Reports RROI95 Ventilation system hygiene - A review of published
infomlatioo on lhe occurrence and ffects of Olltamination Rl~02J95 Air-to-air heal rec v ry RR0395 rnfluen e of HV C on smoke detectors
ATlONAL ENI [ERING SPECIFICATION LfMITED Southgatc hamber 3739 Southgate Street Winchester S023 9EH (Telephone 01962 842058 Fax 01962 R(8982) BUfLDING S RVICES RESEARCH AND [ ORMATION ASSOCIATIO Old Bracknell Lane West Bracknell Berkshire RG 12 4AH (Telephone Brackl1eU (01344) 426511 Fax 01344 487 -7 )
Application Guides AGln4 De tglJing Vana~le Volume middotylans for KOOnl
iir Movement AG1I91 Commissioning of V Sylcms in Buildings 11 6194 Fire Dampers
B) 94 cntiJalion or KitcneTls
AG389 The Commls ionin of Air Systems In Buildmgs AH2192 Commissioning of Bern - A ~ode of Practice TN2417 I Fire Dampec il) Ventilating Ducl
BEATING VENTILATING A AIR CONDITION G MA UFACTURERS ASSOCIATIO (HEVAC) HEVAC Henley Road Medmenham Marlow Buck SU 2ER (Telephone 01491 578674 ox 01491 575024 Emoimiddot infofetacouk)
Publicatjons Air Diffusion Guide Guide to Air Handling Unit Leakage Testing Guide to Good Practice Air Handling Unit Real Room Acoustic ~ st Procedure Specification for the ertiiicatioll ofAir Filters Method of Test for Water Rejection PerfOnTlatce of Louvrcs Subjected 1(1
Simulated Rainfall Test Procedure for Acoustic Loo cs Specification 10 Floor GrilJes - Types Performan e and Method ofTest Specification for the Determination of the Collection Efficiency of SilJ1d
Trap Louvre Domestic Mechwlical Vclltllalion Systems with Heal Recovery Fan Application Guid
~an and Ouctwork Installation Guide Guide to Fan Noise and Vibration
pecification of Requirements for JallJral Smoke and Heal Exhausl Ventilators
pecification for Powered Smoke and Heat Exhaust Ventilators
Specification of Requirements for Smoke Curtains Design Gujue of Smoke Ventilation for Single Storey Lodustrilll Building~
Including those with Mezzanine Floor and IIi Racked Storage Warehou es - Issue 3
Guidance for the Design of Smoke entilation YSlem for Covered and Undergrollnd Car Parks - lssue 1
Application of SOloke Control Equipment and Syst m Guid to Good Practice - Isue J
58
DW154 Sp(C~tiifitiol for Plastics Ductwork
BRITISH STANDARDS INSTIT TION Sales Department 101 P ntooviLle Road London NI 9ND (felephone 020-78 1 78801)
CP 413 1973 Ducts for building ervices
SS 476 Fire tes on building matenals and lruc(ure
Part 4 19 4 Non-combustibility lest or materials
Part 6 I Fire propagation lest for materials
Part 7 1993 Surface spread of tlarnJ tesls for materia
Part 20 1987 Fir resistance of elements of construction
Part 21 1987 Fire r sistlUlce of loadbeanng elements of construction
Part 22 1987 Fhe istallceofllon-loadbearing elemcllts ofconsttuclion Part 23 1987 Contribution of componcnts to the fire resistance 0 a
structure
Part 24t987 Fire resi lance of wl1lilation ductl
SS 5588 nan 919 0 Fire Precautions III thc desIgn and OOSlnJ lion of buildings
S 729 1971 Hot dip galvanized oatiugs (or irOIl aod stcel articles
BS 1449 Steel plate sheet and Irip
Pan 11991 Carbon steel plate heel and strip Part 2 1983 Stainless steel plate sheer and strip
and
B middotENJOI49-2 996 BSEN 10149- 1991)
BSEN 10131 1992
BSEN22063 Sprayed metal coarings 1994 Protection of iron and steel by aluminium and zinc against
atmospheric cOlosion Irotectiotl of iron and ste I against corro ion and oxishydation at elevared temperatures
BS 353 1981 Glossary of lerms relnting to thermal insulation
BS ISO 1479 Self-tapplngscrewsandmetallicdri c crew
B -lSO 7049
1994
B 4800 1989 Painl colour for building purposes B 4848 l0 rolled structural steel sections
Part4 1972 Equal and unequal angles BS 5422 1990 Specification for the use of therm illuating matcriulS
SS 5720 1979 ode of practice for mechanical veutilating and air C 11shy
dirionin bull in building
l3S PR 12814-1 Bend resting for plasric welds
SS PR 12814-2 Tensile testing for plastic welds
SS PR 13067 Appro altesting for plastic welds
BS PR EN I 100-] Vi ual in pection ofplaslic welds
SHEET METAL AND AIR CONDITIONING CONTR-CTORS NATIONAL ASSOCIATION INC (SMACNA) Headquarters 420 I Lafayeue Center Drive Chanlilly Virginia 2051-1209
Mailing Address pa Box 221230 Cbantilly Virginilt120 153-1230
Telephone (703) 803-2980 Fax (703) 803-3732
Accepted IJJdustry Pl3Gtice for Industrial Duct Constnlelion 197 ) i-rchitecmral Sheet kwl Manual ([993)
Comractors Guide lor Modification 10 ooslruerion Colllraets 1993 Ducted Eleclric Heat Guide for ir Handling Ssrerns (1994)
En~rgy ollservatioD Guidelines (1984) Energy Recovery Equipment yslClllS (199l
Fibrou GIns Duct onS1ntClion Standards (1992)
Fire Smoke amp Radiation Damper In tall Guide for HVA Syst ms (1992) Guide t leel Stack 1(95)
HVA Air Duct Leakage Test Manual (19 ) HVA COlllmissioning lvlanual (1994)
H A Duct Construction Standards-Metal amp Flexible (1995) Addendum 01 (Nov 1997)
HVA Duct Systems Inspection Guide (1989)
HVA ySlems-Application (1986) nVAC ByternS-DLlct D ign (1990)
HVi Systems-Testing Adjusting amp Balancing (1993)
indoor Air Quality Manual (1993) tcheu quipment Fabrication Guidelmes (1990)
Managers Guide for elding (1993)
Rectangular Industrial Duct Cons1TUction Standards (19 0) Round Industrial Duct oustmction Standards (1977)
Sei mic Restraint Manual (1991) (wl Appendix E 1993) SMACNA Ma le Index ()fTechnical Publications (1995) Tbennoplnstic Duct CPY ) Construction Manual 1994)
DEPARTME OF THE ENVIRO MENT (Publications Centre) H Stationery Oflice 5 Nine Elms Lane London SWS 5DR
MampEJ 011972 Electrical in tallat1011 in buildings ( ew Editiou)
IampE 0319 Healing hot and cold wat r steam and gas losla1lations for buildings
M amp - No4 1970 Central heating and hot and cold ~ ateT in tallations for
dwelling
M amp ENo100 1971 Mechanical ventilation for building~
ASSOCIATION FOR SPECIALIST FIRE PROTECTlO As ociation House 235 Ash Road AJdershot Hampshire GUl2 4DD
Telephone OJ25221322 Fax 0 J252 333901
lublicalioos Fire Ratcd and moke Outlet Ducrwork An Industry Guide t Design and InSlalla lioll
HEALTH AND SAFETY EXEC TIVE Rose Court 2 Southwark Bridge London SEl 9HS Telephone 020-7717 6000
TWJ THE WELD G TlTUTE Abington Hall Abington Cambridge CB16AL Telepbone 0 J223 89162
Publication DatJ Oil w~ldll1g of lhermopla lics
59
DW154 wciiwlioll for Plastics Ductwork
A -=--DIX
Factors
Specific gravity shy pp = 091 approx UPVC = 14 approx
Some miscellaneous conversion factors
To convert
Length Inches to millimetres Feet to metres
Multiply by
2540 03048
To convert
Millimetres to inches Metres to feet
vIultiply by
003937 3281
Area Square inches to square millimetres 6452 Square millimetres to square inches 000155 Square feet to square metres 00929 Square metres to square feet 10764
Volume Cubic feet to cubic metres Cubic feet to litres Gallons (UK) to litres
002832 2831 4546
Cubic metres to cubic feet Litres to cubic feet Litres to gallons (UK)
35315 00353
022
Mass Ounces to grams Pounds to kiJograms Tons to tonnes
2835 04536
1016
Grams to ounces Kilograms to pounds Tonnes to tons
003527 2205
09842
Volume flow Cubic feet per minute to cubic Cubic metres per second to cubic
metres per second 0000472 feet per minute 2119 Cubic feet per mIDute to litres Litres per second to cubic feet
per second 04719 per minute 2119
Motion Feet per minute to metres per second 000508 Metres per second to feet per minute 197
Pressure Inches water gauge to millibars 2491 Inches wateJ- gauge to pascals (Pa) 2491 I Pa = I ewton per square metre = 10-2 millibars
60
Heating and Ventilating Contractors Association Esca House 34 Palace Court London W2 4JG
Tel 020 7313 4900
e-mail contact Itvcaorguk web site wwwhvcaorguk
Fax 020 7727 9268
DW154 SJecilimtol for Plastics Ductwork
Expansion joints
Fig23 Moulded bellows type (rectangular and circular)
Fig24
~F aiblc sleeve
__ liding sleeve
~~~~
Sleeve type (circufar)
Fig 25
AIRFLO
COnlinuou~
weld~
Flexible Iceve
PV A HOWN pp SE BACKING FLATS AS FIG 2
Sliding lee c Co1linuou
weld
Flanged sleeve (rectangular and circular)
25
DW154 Specificatiol for Plastics Ductwork
Flexible con ections
Fig 26 Flexible sleeve with clips (UPVC and PP)
--__ Flexible I eve
I
I
I CODn clioD to plant ~
Band clip
Fig27 Welded flexible sleeve (UPVC only)
Plastic)sed PVC slceve ~-- onll11uo1sly welded
onrreclion to planl ~
Fig28 Flanged flexible connection (UPVC and P )
t sp dally moulded flexible flanged connCClitlll
boil
C)nneclion to plant ~
26
DW154 Specificotiol for Plastics Ductwork
182 LOClt1tion Flexible joint are typicltllly lIsed at building expansion joint and fan inletsoutlets Any others required should be indicated on the de ign drawings Care should be taken to maintain alignment across jointsconnections
183 Length Flexible Jomts shall be kept as short as pra middottieable above a minimum eft ctive length of SO mm In no ca e shall a flexible joint exceed 250 mm in lengtb
184 Connections to rectang a ducts With flanged rectangular connections Ule tlexible material shall be held in pLace with flat pIa tic strip of not less U1an 6 mm thick ltlttached to the flanges using uitabJe fixings The more heavy weight type of fleAible mateLial may also be obtained formed into a channel ection with corners fitted to give a neat air tight j int For pigot connections the Be ible material shall b held in place with flat pIa tic trips n t less than 6 mm thick
t 85 Connections to circular ducts With tlanged circular connections the flexibl material shall be held in place with flat plastic backing strips or proprietary clip bands with screw or toggle fast ners
186 Welded flexible connections (Rectangular and Circular) Where the parent and llexibl material are from imilar ba ed products they can be joined to the duct u ing the welding method described in Section 823
19 PROTECT VE FINISHES
191 nles otherwise stated all ductwork shall be mallllfactured in mat fial as pecified in tbis specification Any special coatingpaint fmishes to be provid d by the duct work contractor sball be advisd by th de igner
20 CONNECTIONS TO BUILDING OPENINGS
201 Fanning and finishing building op nings are not the repoJlsibjlity of the duftw( rk contractor and the note that follow are for guidance purpo e only
2011 Openings in brick block or concrete walls shall have inset frames to provide a suitable means of fixing grille louver masking flanges or the tlanged ends of ductwork The illset frames shall be conslnlcted to maintain the structural int grity of the wlll and where applicable cavities shall be suitably lined
2012 Openin s in dry linino partItIons shall have inset frames a 2011
2013 Openjngs in cladding walls and roofs shall have flaoged leevesframes to provide a suitable means of fixing a 2011
2014 Horizontal and vertical opening xposed to oLltside atmo phere hall
be provided with a suitable weathering fini h at the external face especially where profiled cladding is used
2015 Timber framed op nings are not permitted In fj re compart ment barriers
202 Ductwork connections to building openings hall have a flange of suitable profile to permit practical fixing to the openillg frame In selecting the profile consideration shall be given to Tabl~s 2 and 10 in this specitication relating to duct ize and rating Gasket strip or sealant shall be ltlpplied between the tJaoge and building op ning frame
21 DISCHARGEEXHAUST TERMINAL
21 Tbese shall be vertical open ended and designed to meet and comply with current r gularions on contaminated flue The designer hall ensure that the de ign and perf rmance i suitable for its intended purpose Examples of some typical terminal designs are SbOiD in Figbull 102 10 bull 104 amp 105
27
DW154 SpedjimioTl for Plastics Ductwork
22 THERMAL INSULATION
221 The provision and application of thermal insulation to ductwork is not the responsibility of the ductwork contractor
222 Where ductwork is required to be preshyinsulated the specification should be agreed with tbe designer
223 Where the temperature of the air within the duct promotes condensation on the exterior surface of the duct and cause moisture penetration througb the thermal insulation vapour scaling may be required and in this case the most important requirement is to limit penetration of the seal
The extent of any vapour sealing of ductwork thermal insulation and the support method to be u ed must be clearly pecitled in advance by the designer
224 For detailed information on the thermal insulation of ductwork reference should be made to BS 5422 1990 which covers the specification for thermal insulation materials on pipes ductwork and equipment (in the temperature range -40degC to +700degC) and BS 5970 1992 which is a Code of Practic for Thermal Insulation of Pipework and Equipment (in the temperature range -lOOdegC to +870degC)
23 FIRE RETARDANT FINISHES ON PLAST C DUCTWORK
231 The designer should note tbat ductwork constructed to DW154 has no teted fire rating or information see Appendix C
24 REINFORCEMENT OF DUCTS WITH GRP LAMINATE
241 General Where ductwork is required in larg T izes than are covered by Tables 2 4 6 amp 7 or with the increased strength sometimes necessary for industrial use external reinforcement is normally pwvided by applicatioD of glass fibreresin laminate
GRP systems will bond satisfactorily with standard UPVC sheet but for pp it is
nece sary to use a specially prepared sheet with a glass fabric backing incorporated dOling manufactllfe
The detailed techniques of fabrication using GRP are outside the scope of this speci lcation but the following notes are offered for guidance of ductwork fabricators
242 Materials
2421 Quality The laminate is made up of polyester resin complying with BS 3532 and glass fibre complying with BS 3496 or BS 3749 The nominal ratio of resin to glass fibre should be 7030 by weight
2422 Minimum properties The laminate shall comply with the followiog mini mum pbysical properties
Tensile strength - 70 MNm Tensile modulus - 7 Gl m Flexural strength - 140 M Im Bond strength (hetween laminate and substrate Not less than 7MNm Bmcol hardnes Not le s than manufacturers specification
The GRP reinforcement educe the expansion of the parent material but the resultant stre ses arc well within rhe strength of the bond However the Iinear thermal expansion curve shown in Figs 34 amp 35 will serve as a guide
Surface resistivity electrkal propcltles and acoustical propertie are similar to the relevanl unreinforced materials The fire retarding properties of GRP may be improved by the use of specialisl laminating resin
2423 Forms available GRP Laminate should be built up from the separate materials ie resin aod glass fibre in the form of chopped
I strand mat or spray ravings
28
DW154 Spcification for Plastics Ductwork
2424 Workshop conditions Polyester resuls are sensItIve to lmperature and the workshop hould b maintained at a temperature of herween 20deg and 25degC HiOh relative humidities and damp onditions should be avoided A good rate of air change must be pro icled pJeferably by m chanical ventilation
2425 Storage of materials Resin and urin o agents shouJd be stored in dark cool condirions away from the working area and in confonnit with statutor requireshyments for tJle middottorage of flarmnable liquid Because of Ule Limited torage lif of the unmixed resin and curing a eot mal lials ~hould be ch eked before use to enLlfe that they are within the manufacturer pe ified sh If life (usually ix month from the dm of manufacrure)
Glass fi re should be stored separately und r clean dry conditions
243 Surface preparafon
2431 UPVC To achieve the specified bond strengtll the urface to which the GRP is applied mut first be thoroughly cleaned and then etched either by mechanical means or by the use of a suitable solvent
2432 pp with glass fabric backing To achieve the specified bond middottrength the fabric backing must be thoroughly impregnated Witll resin
244 Mixing the materials for use The re in 1 a three part mix compri lng base I sin hardener and accelerator The manufactur rs pecj[ied proportions are critical and th llUxmg sequenc pecified must be meticulously foUowed
The resin has a very limited life after mixing and before u e It is dependent on the characteri tics and bulk of th resin the alllount of hardener the degree and method of acceleration and the workshop onditions
245 Methods of application
2451 General The mixed resin may be applied by hand or b pray c1epoition The operation must b completed within the gel time of th y tern and tbe laminat fully cOI1olidated to achi v the phy ieal properties pecified
2452 Hand lay-up The duct surface i coated by hand with resin Llsing a brush and a mar of gla fibp orked in until full consolidation achieved Th proc is repeated untiJ th requird thicknes i obtained
2453 Spray depo Won The duct surface is coated WiUl re in by spray gun with the chopped glass roving added through a separate nozzle The full thickne i obtain d in layer with con olidation of each layer by hand roller
246 Construction
2461 General M ini mum COllst ructional requireshyments are pe itied ill Tabl 10 for rectangular and Table 1J for circular dUClS
2462 Joints and stiffeners Fig 29 30 31 32 amp 33 hoI TOSS
joint and tiffener for reinforced UPVC and PBPP duct
247 Worki g practices The fabrication of ductwork pecifiecl ill thi document i not affected by the addition of GRP
29
DW154 SfJcdJicatiOt for Plastics Ductwork
Table 10 Minimum constructional requirements shy
Longer Side Minimum Sheet Thicknes and
GRP Reinforcement
UPVC FBIPP 1 2 3
mm mm mm Up to 1000 3 plus 3 plus
06 kgm2 06 kgOIl GRP GRP
1001 to 2250 45 plus 3 plus 06 kgm 12 kgm
GRP GRP
2251 to 3000 45 plus 6 plus 12 kgm 12 kgm
GRP GRP
Cross Joints
UPVCFBPP 4
mm socket amp spigot
as Fig 30 or flanged as Fig 29
75 x 9 flange welded on both sides as Fig 29
75 x 9 tlange welded on both sides as Fig 29
rectangular GRP reinforced ducts
SlifTeners Maximum Spacing Between
JointsSljffeners UPVCIFBIPP UPVCFBPP
5 6 mm mm
75 x 9 flat 800 as Fig 31 or
50 x 50 x 5 plastic or MS inverted angle as Fig 32
or tormer as Fig 33
75 x 9 flat 600 as Fig 31 or
50 x 50 x 5 plastic or MS inverted angle as Fig 32
or former as Fig 33
75 x 9 flat 600+shyas Fig 31 or 50 x 50 x 5 plastic
or MS inverted angle as Fig 32
or former as Fig 33
Note 1 On rectangular duct up to 400 mm longer side no stiffeners are required 2 Applies to Tables 10 amp I I For COlJstructional operating temperature limits refer to Part 2 clause 5A 3 Tables 10 amp II apply to all pres ure classes up lo ]500 Pa
Table 11
Diameter
1 III
lJp to 1000
1001 to 1750
1751 to 2500
Minimum Sheet Thickness and
GRP Reinforcement
UPVC FBPP 2 3
mm mm 3 plus 3 plus
06 kgm 06 kgm GRP GRP
45 plus 3 plus 06 kgm2 18 kgm
GRP GRP
6 plus 6 plus 12 kglm2 18 kgm1
GRP GRP
Cross Joints
UPVCFBPP 4 III
socket amp spigot as Fig 30 or flaoged as Fig 29
75 x 9 flange welded on both sides as Fig 29
75 x 9 flange welded 00
both sides as Fi 29
inforced ducts
Maximum Spacing Between
JointsStiffeners UPVCIFBPP
6 mm 2400
800
600
Stiffencrs
UPVCFBPP 5
mm 50 x 9 flat as Fig 31
75 x 9 flat as Fig 31 or former as Fig 33 75 x 9 tlat as Fig 31 or t()rmer as Fi 33
ote On extruded tube tip to 600mm diameter no stiffenergt are required
30
DW154 Specificatioll for Plastics Ductwork
G - Cross joints and tiffeners
Fig 29 Flange Joint Fig32 Stiffener shy inverted angle
M artiPfCuQkbdd erttpObri) Wl111 RP tlddtlt
_- GRPloliu] lh~
Fig 30 Socket and spigot joint Fig33 Stiffener shy use of former
Fig 31 Stiffener Flat
I Pv FlPP ~ ~lmJaDUA1) d
OMrlQ rrnall 1( tQlS
25 STANDARD COMPONENT DRAWINGS AND ABBREVIATIONS
251 The illustrations in this section not only highlight where applicable geometric limjtations for the de ign and manufacture or ductwork components but also recommend
standard drawing representation terminology and abbreviations for both duetwork components and some of the more commonly used ancillaryplant items
252 Designers and surveyors should note that bills of quantities should provide a full description
3)
---
v
DW154 Spcc(fim(ml for Plastics Ductwork
Fig 34 Linear Thermal Expansion
u c 0 N ro 0)
b 0)
S
sect0
5 oS cl) 0)
~
on ~ ltl
c U
-30 -20 -10 0 10 20 30 40 50 60 70 80 90 TEMPRATURE C
~ V
-
~~c_ ~
~V
V ~
-7 ~
-- ~V ----
v
-6
+14
+12
+10
+8
+6
+4
+2
0
-2
--4
ig 35 Typical Design Stress tor UPVC and P
7
6
r shy 5E
-c E----0 4t) VJ 0)
ci5 0Jl 3
~
0)
Cl
2
1
o
UPVC
1
000
1
1
pp
- r-- shy r----- shy - t--shy I
__0
-30 -20 -10 0 10 20 30 40 50 60 70 80 90 TEMPERATURE C C
Note Figso 14 amp 35 shaded area refers to GRP reinforced duct
32
DW154 Speciicfltirm for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - REC ~NGULAR
Splilt~r Posilion W-mm pliucr
A B c 40]--QOO 1 W - -
601-1000 1 W4 Wf2 -
1001-1800 3 WI W3 W2
FIG DRAWING DETAfiS
tU]36 ATI Straight Duct with socket and spigol joint
rn [037 Straight Duct with flanged joints
[I []38 Straight Duct with flanged joints
rkJ Short Radius Bend
39 Applies to any augl and for duct up to 400 n11n wide
Minimum (I1m31 radills = 100 mm
Medium Radius Bend (a illustrated)
[kJ Applies to any angle
40 Long Radiu Bend Similar but radius = W
Throlll radius = W2 Applies to any angle
- Short Radius Bend with plitlers
I -shy -shy u co - t lt Li--_ 41 t 0 ~ I I I
~ I
L 1W
Minimum waal radius = 100 mm Splitters not required in bend angle less than 45deg
42 QJ1 Square Bend with turning vanes ij
3
DW154 SP(L~ficatioll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - RECTANGULAR
FIG DRAWl G DETADS
43
~
I v
L L Radius Tee with internal deflectors
44
~ Radiussed Twin Bend
45
Imiddot
er Swept Branch
46 U-
Sqoare Tee with Turning Vanes
47
~ f
Breeches Piece
48 0 y l Piece
34
DW154 Specificatioll for Plastics Ductwork
STANDARD COMPONENT RAWINGS - ECTANGULAR
55
54
51
50
53
52
49
FIG
~MX
RAWlNG
DmiddotMAX
EfjMAX
Minimum throat rndius = 100 mm
Rectangular shy Round Transformatioll
Eccentric Taper 225deg max in either plane Spliller are required for angles greater than 225deg and hould bi eet the angle between any side and duct centreline
DETATLS
Angled Offset
OUset Taper Splitters are required for angle greater than 22 0
and shoold bi eet the angl between any side and dUCI centrelinc
Mitred Offset
Concentrk Taper 2250 max in ither plane SpUtters are required for angle greater than 225deg and should bisect the angle between any side and duel c ntreline
Radiussed Offset
35
DW154 Splcilcuthm for Plastics Ductwork
STANDARD COMPONENT DRAWINGS ~ RECTANGU AR
Branch ducl DimCllsions widlh (W) (A)
urnl mm up lO 200 75
300 100 400 125 600 150
Ocr 600 200
FIG DRAWlNG DETAILS
56 poundplusmni~~ Rectan~lar - Flat Oval Transformation
57 [ Square Branch
58 er Angled Branch
Branch dUCI Dimensions wfdth (W) (A)
[- mm mm59 3shy Shoe Branch Up (0 200 75
--shy AIshy + 300 100
400 125
450 MAX 600 150
Over 600 200
Branch duct DimensIOn
rP X width (W) A)
60 - 1--shy _
~ mm mm
Bell Mouth Branch pto 200 75 300 100 t 400 125
600 150 Over 600 200
0=0 61 -
~ Bell Mouth
- shy T 4-5deg M x
--I 1-shy
TJ
62 X I ] I
Tele-scopic Joint I Illustrated with flangeL
X63
SBD Single Bladed Damper
36
---
DW154 Spedicatioll for Plastics Ductwork
STANDARD OMPONENT DRAWINGS - RECTANGULAR
DRAWING DETAILSFIG
64 on-Return DamperNRD shyshy
shyXbull
Multi-Leaf Damper Can be piggoted or flanged oppo cd or parallel blade
Alternative controls areshy
q p [gtshy
J HD65 Hand
~MD otori ed
PO Pneumalic
L-lt
l 13G 66 Blast Gate DamperX X
FireSmoke DampersSleeves
211r Ratinggtshy----
L_-
---
----
r----
Ir-- shy
IL- _-l
2hr
With i tallation frame
67 41 r Rating
4hr
Smoke damper SD
Intumc cent Sleeve L-d
37
DW154 Specijicutiolt for Plastics Ductwork
FIG
68
69
70
71
STANDARD COMPONET DRAWINGS shy REC ANGULAR
DRAVING DETAILS
gtshy Access Openings
AP 6 Access Panel - Rerno able
w [ ~ Access Door - Hinged
I ~le Inspection Cover
le -I reg -lt
~X X Flexible Connection
~ Drop Cheeked Radiussed Twin Bend
U Drop Cheek Bend
I
72 Air Flow SymbolX
38
DW154 Specifim[ioll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - ECTANGULAR
FIG DRAWING DETAILS
73
74
75
76
77
Q
Q
rp---t
~
V- I Ir---I
JL --11
THE ABOVE DETAILS TYPICAL PLENUM
Air Terminal Plenums
Plenum with side connection
Plenum with top connection
Cover plate with connection
Special plenum with connection
elescopic conn ction in direction of air flow
39
DW154 SpecijicotiOll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG
78
79
80
81
DRAWING
-23~---pound3-(MALE) (FEMAJE)
-t=j--_j(--d-shy
--L
~ THROAT RADI S= D AS T NDARD
e ~
THROAT Rjf)lU = D A MU)
DETAILS
Straight Duct With male and female connectors
Straight Duct With flange joint and slip joint
Bend MouldedIFormed Applies to any angle ego 30deg45deg60deg90deg Medium radius bend as illustrated Long radius similar but throat radius 0
Segmented Bend 90deg four section minjmum as illustrated
Other Angles 60deg = 3 sections 45deg = 3 sections 30deg = 2 sections
I
i
40 shy
DW154 Speciicafinll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG DRAWING DETAlLS
82 Segmented Twin Bend Radius = D2 max
May also be fabricated from tube
83 Equal Tee MouldedIFormed
84 -~ 1in Bend MouldedIFormed
85 Taper Concentric 1 0 as iUu trated Eccentric 30deg iJJcLuded angle
86 Short Taper
41
DW154 SpcUicatol1 for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG DRAWING DETAILS
87 30 max Offset
Angle Branch
Bran h dUCI Dimcnsions dia (D) lA)
Shoe Branch mm mm 88 Cl
Off rectanguJur Up 10 200 75 lOO 10 400 125
- 00 150 Over 600 200
Bl1IllCh duct DimenlOns din (D) (A
~-$a-Conical Branch mm mm
89 Also acceptable with Up 10 200 r
full conical surface 300 10
400 125
END VrE -shy 600 150 Over 600 200
90
m 75
100 12 150 200
mm Up to 200
_ 300 400
600 Over 600
iUtred Branch
Shoe Branch
J-L----U ~ Bell oulh Branch
ENDV1EW
93
92
91
42
DW154 Specificatiol for Plastics Ductwork
STANDARD OMPONENT DRAWINGS - CIRCULAR
FIG
94
DRAW G
I
~ 30deg 090deg
Breeches Piece
DETAILS
95 amp-----~ Blank End
~-----p Multi-Leaf Damper Can be piggolcd or fianged opposed or parallel blade
Alternative controls areshyri=-+- L-T~
I
---
LT~
I r- -
-+1
J HO Hand96
bMD Molori cd
PD Pneumatic
tl-shy bull
Single Bladed Damper 97 ~ saD
on-Return Damper Vertical application only 98 m~D
43
DW154 Sf1tcificatioll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG
99
100
101
102
DRAWING
$ I-
2hr
1 4hr
SD
~v I I
CO TINENTAL COWL
DETAILS
Iris Damper
Fi reS moke Dam persSleeves
2hr Ratillg
With installation frame
4br Rating
Smoke damper
Intumescent Sleeve
Access Openings
Access panel - removable
Access door shy hinged
fnspection cover
Discharge Continental Cowl
44
DW154 Sp(Cii(ltJll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
DRAWINGltIC DETAns
-
I
I
~
I I I High Velocity Discharge Terminal 103 I
I
I I
J I I 1 ~--
Offset Stack Discbarge Terminal 104 1
~ I e --(-
I
N
I
I
I~
I I Vertical Oischarge with Weather Cowl 105 I
--1--1 I
I
GAPI I
RTl AL DISC) lARGE WITH W ATIIER COWL
45
DW154 SpecUicatoll for Plastics Ductwork
STANDARD COMPONE T DRAWINGS - PLA TEQUIPMENTIMISCELLANEOU
FIG DRAWING DETAILS
106 ~~~ Rectangular Attenuator
107 ~- Circular Attenuator
108
~ Beod Attenuator
109 J ~(f) Heating Coil
110 J ftte Cooling Coil
III Jc[ Electric Heating Coil
112 X F
Humidifier
113 [H XX Axial Fan
114 ~fB1famp Noo-standard Ductwork Cross hntchillg (of any separate type) indicates by reference to a key any non DVil54 ductwork system
115 2llIIIIJIIIIIll Flexible Ductwork
46
DW154 SJeCUicll(iol1 for Plastics Ductwork
TABLE 12 - STANDARD ABBREVIAT ONS
ABBREVIATION FLL
AD Acces Door
AFF Axial Flow Fan
AHU Air Handling nit
All Aluminium
AP Acess Panel
AT Attenuator
AV Air enninal Unit
BE 81ank nd
BQ Blast ate Damper
CC Cooling Coil
CF Centrifugal Fan
CTA Cross alk Attenuator
CVU Constant Volume Unit
DP Drain Point
EEC Electric Heating Coil
El Expansion Joint
FAl Fresh Air Inlet
FA From Above
FB From Belo
fBPP Fabric Backed Polypropyl-ne Sheet
Flexle Flexible Connection
lexfD Flexible Du t
C False Ceiling CO an oil Unit
fD Fire Damper
FFL Finished Floor Level
FJ Flanged Joint
FOAM Rigid Polyurethane Self xtinguishing Foam
FOB Flat on Bottom
FOT Flat on Top
GAM Galvanised after ManufacttrJc
GRP Glass Reinforced Plastic
GSS Galvanised Sheet Steel
HC Heating oil
HD and controlled Damper
HH Hand Hole
HL High Level
HVD High Velocity Discharge
IC Inspection Cover
ID lri Damper
IFS Intumescent Fircleevc
47
DW154 Specification for Plastics Ductwork
TABLE 12 - STANDAR ABBREVIATION CONTINUED
ABBREVIATION
IU
L
tv1D
MS
NRD NTS
OBO
OE
PHD
PD
PP
PP
PRD
PVC
RFC
RSC
R
SBO
SO
S1 TST
SSL
TA
TB
TO TJ
TP
TV
TV
OS
UPVC
S
V
VAV
50 RSA
FULL
Induction Unit
Low Level
Motor controlled Damper
Mjld Steel
on Return Damper
at to cale
Opposed Blade Damper
Open End
Parallel Blade Damper
Pneumatic controlled Damper
Polypropylene
Self xtinguishing Polypropylene
Pressure Relief Damper
Polyvinyl Chloride
Rolled Form Chamlel
Rolled Steel Channel
R fUnit
Singl Blade Damper
Smoke Damper
Slip Joint
Stainl t el
tructural Slab Level
To Ab vc
To Blow
Top Down (In Direction of Flow)
Telescopic Joint
Test Point
TU111iog Vane
Top Up (In Direction of Flo )
Voles Otherwise Stated
Unpl3sticisecl Polyvinyl Chloride
Underside
Ultra Violet Light
Variable Air Volume
Rolled Steel Angle (Vith Size)
48
DW154 SJeriiflllioll for Plastics Ductwork
A2 DUCT PRESSUREAPPE DXA Ductwork con truct d to DWIl54 will bebullbullbullbullbullbullbullbullbullbullbullbullbullbull
Air Leakage From Ductwork To be read in conjunction with DW143 A practical guide to Ductwork Leakage Testing
CAUTION As highlighted ill both this docul1lenr and DW14 I lot ellough emphasis can be placed 01 the fact that except for high pressure class C the much more stringent ductwork constructional standard brolght about b the general acceptance of DW154 have irtlally negated the requirement for leakage-testing It is essential lO realise lhat except where it is mandatory this doclllllelll is nOl an endors ~lIlent of the rourine testing of ducts bllt purely a guide to outline the procedures for cononnity with the air leakage limits ill Table l Where the specified methods of assembly and
A3sealing of dlcls are u ed a vi ual inspection wil ordinarily sl~fll e for ver(iatioll of a well engineered and a ceptahfy airtight COl1strucrioll WHERE NOT MANDATORY DUCT LEAKAGE TESTING IS GENERALLY AN UNJUSTIFIED AND SUBSTANTIAL EXPENSE
A1 INTRODUCTION L akage from ducted air distribution systems is an Lmportant consideration in the design and operation of ventilatjon and air conditioning middotystems A ductviork t)ystem tbat ba limited air leakag within defiucd limits wiH cnsUft
that tile design characteristics of the sytem can be maintained It wilJ also ensure that energy and operatLonal cosb are maintained at optimum levels DucLwork constlucted and Ulstalled in accordance with DW154 should minimise a level of air leakage that it) appropriate to tll operating static air pre sur in tile system
A4However it is recouuised that tbe environment in wtJich middotystems are installed is not always conducive to achieving a predictable level of quality in term of system ajr leakage and it is therefore accepted that designer may sometimes require tlle ystem to be tested in part or in total It should be ecogni ed that the testing of duct systems add a ignificant cost to the installation and incur some extra tjm within the programme (Se 47 and 64 re mandatory te-sting)
manufactured to a structural standard that is compatible with the system operating pressure There are three classes of duct con truction to eorre pond with the three pre ure clas meations Class A Lo pressure ducts suita le for a maximum positive operating pressure of 500 Pascal and a maximum negative pressure of -500 Pascals Class B IVledium pressure ductmiddot suitable for a rnaxilnuJJl positive operafjn o pressure of 1000 Pascals and a maxllnum negative pre sure of -750 Pa cal Class C High pre sure ducts suitable for a maximum po ilive operating pressur of 2000 Pa cals and a maximum negativ pres ur of -750 Paltcals
LEAKAGE FROM DUCTWORK Leakao-e front pia tic air ducts occur at the joint~ and is therefore proportional to the total surface area orthe du twork in th system Tb level of leakage i imilarly related to tIle air pres ure in th du t system and whilst there LS n precis formula for calculating the level of air los it i generally accepted that leakage will increase in proportjon to pressure to rbe pOvver of 065 The effect of air leakage from high pressure velocit ductwork is critical tn terms of system perfomlan dege energy consumption and the risk of high frequency noise as ociated with leakage These problems are le critical with medium pressure 10 ity systems but should be con idered Low pres mevelocity ducts present the lowe~t
ri k in tenn of tbe effect of leakage on the operation of the s stern
SYSTEM LEAKAGE LOSS As there i no di ct relatLonship between th volume of air conv yed and the surface area f the ductwork sy tern required to match the building configuratmn it is difficult to express air leakage a a percentage of total air volume Similarly the operating pressure will vary throughollt lh 3 system and a leakage is related to pre me the calculations ar comple However it is generally ac epted tbat in typical good quaJjty systems the leakage from
49
DW154 Specificatioll for Plastics Ductwork
each class of duct llnd r operating condition will be io the region of CIa S A low pressure 6 Clas B medium pres un 3 Clas C high pressure 2
A5 SPECIFYING AIR LEAKAGE TESTING Re peeting both the co -t and programme implications a sociated with te ling du 1 for leakage the designer may for example indicate that a particular system is te ted as follow
a) High pressure ducts - all tested b) Medium pr ssure duets - 10 of the
ductwork shall be s eet d at random and tested
c) Low pre sure - unte ed In any case where a random te t i elected for medium pre sure ductmiddot the followin c1au~e is suggested for inclusion by the de ign r
The designer hall elect at random a maxirnwlI of 10 of the dUCl system to bt tested for air leakage The duct hall be tested af the pressure recommended in Table J3 for the assifi atiol for the ectiol1 of the ductwork that is to be tested The tests shall be carried Ollt as the work proceeds and prior to the application of thermal insulation In the event of test failure of the randomlY selected section the designer shall have The right to select two La1her e tiolls at random for resting Where succes ive failures are identified there shall be a Tight to require rhl COl11raCWr 10 apply remedial attention to the complete ductwork system Th contractor shall provide documented eviden e of the calculalions used to arrive (1
the allowable 10 I for the section to be tested and the client or his agent shall willess and sign the results of the test
able 13 Air leakage rates
Maximum leakage of duct work Static
prcssUft Low-pressure edium-prc-sure I Iigh-prebull me diJfercntial Class A Class B Class C
1 2 J 4 Pa Litres per second per quare metre of surface area 100 054 018 ZOO 084 028 300 110 037 400 132 044 500 153 051 600 058 019 700 064 021 800 069 023 900 075 025
1000 080 027 1100 1200 1300 1400 1500
029 030 032 033 035
1600 1700 1800 1900 2000
036 038 039 040 042
Note Recommend d mean test presures are highlighted iD bold type with the actual selection being left to tll test operator
50
DW154 Sfeeiieaioll for Plastics Ductwork
A9
A10
and air leakage classification for the y em under test
DESIGNERS CALCULATIONS The designer can middotaJculate with reasonable accuracy the predicted total loss from a ystem by
a) Calculating the operatin presure in each ection of the sy tern
b) Calculating the surface area of the ductwork in each correspondin pre lire s ction
c) Calulating the allowabl~ los at the operating pressure for each ection of the system (see table 13 for allowable leakage figures)
VARIABLE PRESSUR S IN SYSTEMS De igner can achieve significant co t saving by matchina operating pressures throughout the system to constmctional standard and appropriate air leakage testing eO the practice of specifying construction tandards for whole duct sy tems based on fan discharge pre sure may incur unnece sary costs on a project For example ome large sy terns ould well be classiC ed for I akage limits as follows
Plant room risers CJas C Main floor distriblltJou CIa B Low pre sure outlets Cla A
A6 SPECIAL CASES There may be ~itLlations on a project where circumstance dictate thal pecial consideration be given to containing air loss s eg a long mn of duclwork may incur a di -proportjonate level of air 10 s In ca es such as thi example the designer can specify an improved tandard of airtighmess ie 80 of alJo~able 10 s for la B Ju ts The designer sbould not specif a CIa C t sI at CIa s C pressure for a CIa s B ducl
A7 SUGG S ED RANGE OF TES ING
A8 TESTING OF PLANT ITEMS Items of inline pJant (eg Fig 106 to 115) will not normaUy be included in an air I akage test The dllctwork contractor may indud such itelllS in tbe te t jf rh quipm ot has a certificate of COnfOlnlity for Ihe pres ure clas
bull High pressure duct bull Medium pre sure ducts bull Low pre sur ducts bull Exposed extract syst ID bull Ceiling void extract
systems bull Secondary ducts from
VAV or fan coil units bull Flexjble duct bull Final connections and
branches to grille and diffusers
100 test See A5 Untested UDt sted
Untested
Untested Untested
Untested
SI
i
DW154 SJecijicafion for Plastics Ductwork
ig 116 Permitted leakage at various pressures
Leakage in litres per second per square metre duct surface area
Vgt
o ltgt 0 ltgt N
ltgt Cgt
0 0 cc
0 0
~
g =
g ~
c 0
J
ltgt 0 I
~ ] tn
ltgt ltgt
In ol
~ 0 ~ 8 ~
~
c ltgt ltgt
~ CJ
~ ~ ~ ~ 8
0shyij
~ ~ ~ t
ltgt ltgt 00
l
~
~ Q
c C
~ rshy
e ltgt
I 1
I Cgt ltgtv
c Co ~
~~ ~ 10
I
0 Cgt
fJshyq 410 ) 1 ltgt
ltgt N
~ shy ltgt ltgt
~ I 1
c
52
DW154 Specificatio for Plastics Ductwork
Example of a completed test sheet Test No
General
Name of job N~ jC43Pt(r2lef Building Repound ~(~~0
Part 1 - Physical details
a Section of duct work to be tested ~(diffPIfff~el1f3rd Floor
b Drawing Number g91~~ c ssure aSSJ L atlOn V~Jl~IRfYgtg~~lPre Cl T Class C
d Test static pressure -(9 raErq~ ~~~~-~~J~~~ ~~ ~~~~ll
Leakaoe factor 9~-tre3$ecMz I OM REFTOTABLE 13)e b bullbullbullbullbullbullbull
f Surface area of duct under test Q~tJJItetre$ CPROMCALCU TIO BELOW)bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull ampampamp bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull
g ]Vlaxi mum permitted leakage -~ (~i~~0 ~~r~~ ~~~l-~-11~ ~~~Q
Part 2 - Test particulars
a Duct static pressure reading 9QFt~q~ ~ middot~~~1 ~~
b Manufacturer and type of liow measuring d vice (-~~~cJ~Y-9Q7EYg c Range of measurement of now measuring device QtP)OQ~(e~~~0I~~~~1~I~ ~~~~~~W~
d Reading of flm measurin o device pmiddot IFROM RIO)ftscag ~
I (DERlVED [ROM CHART SUPPUED WITH RIG US 0 ud)1e Interpreted air flow leakage rate ~(~~~f~~~ (~l~~~~~~~~~~~~~~~~~I
f Duration ~~~~~norn~allY l~ lnil1Ut~~d~~~ it1~ W~ Date of test ~(lITled ut by Wltll s ed by ~ ~
(~lJ MIJLrr) (Si~rrfltJUYJ
Printed Name 1~g0f~ Printed Name ~~Y~9~ and Company 7jl~~~~~( UJd CompanY AB COII$Itallt8
Width and depth or diameter
Periphery ength Area
millimetreS millimetres metre qL1are metre
800 x 750 3100 1755 5440
600 x 650 2500 557 1193
300 x 300 1200 120 144
305 din 958 700 670
250 dia 785 450 353
TOTAL 8000
53
DW154 Specijilarion for Plastics Ductwork
pA XB
Guida ce No es For he ransport Handling and
Storage of uctwork
avoid damage to adjacent duct panels In somc ca es particularly on con acts calling f r repetitive sizes the use of timber jigs and spacers may be justified Where reduced bulk and greater protection are major factor such as consignments for export transporting ductwork in L shape sections may justify the increa ed ite as embly co ts
It is recommended that before a contract is finalised that consideration is given to the subject of site acces material handling and storage as tbcy havgt a strong influence on the cost efficiency of the overall activity of ductwOlk installation
B3 Handling To minilnise th risk of damage duct sections should be clearly identified and deliveries to site should be closely linked to the installation programme so as to avoid accumulation of
B1 Storage and Handling of Ra Material Material should be stored in suitably designed racking out of direct unJight Where possible the e racks should be metal to earth Edges of cut she t may be harp and protective gloves are advised Wearing teel toe-capped boots is recommended Most pIa tic sheet is manufactured with smootb mfaces andor is suppLied with protective coating Care must be taken to prevent accidental lippag of stacked materials Beiuoshy good electrical insulators the movement of stock unless earthed will allow the build up of stati All stock shapes are chemically stable at normal temperature Whil t some raw materials used in their manufacture may themselves pre ent a toxic hazard once incorporated into the lOck bape they no long r constitute such a hazard and no dermatitic bazard are known nor are any
unfiJied ductwork and minimise double handling It is important to recognise that ductwork panels joint and corners arc susceptible to damage and care must be taken wheu band ling such material through a site During handling individual item of duct work may be liable to light cross sectional deformation until thev become an integral pan of a completed ductwork system Whilst this may temporarily detract from its intended appearance thi deformation will not have any detrimental effect on the functionality of the finally a semblecl system Installation of duct work and asociated plant items ill illevitably involve manual handUng The responsibi Iiry of employers and employees to a ses the risk of personal injury during mallual handling operations is et out in the HS E publication L23 Guidance on Manual Handling Regulations 1992
environmental problems expected 84 Site storage
B2 fransport Large capacity vehicles with high-sided open or closed-top bodies are tlle mo t suitable for the transport of dllctwork Careful consideration should be given to the
Adequate floor space IDust be provided within tbe building for the site storage of ductvork Such storage shalt make due allowance for thc stOf(ne of ductwork in stacks such that access ~ egt
between them is of sufficient width to pennil the removal of item without interference to
unloading of transport on sit a not all siJes b n fit from the material handlino- and access facilities that exi [ in a manufacturing workshop such as crane- fork-lifts or loading bay Site handJiog facilities along with
adjoining sta ks Ductvork components should be positioned so a to avoid crushing Ductwork of small panel size may be stored horizontally however care should be exercised to ensure that tack sizes are limited 10 within
ehicular acce s restrictions may itilluence the type and ize of transport to be uWised
engtlls of ductwork should be positioned 0
the tmctural strength of the duct sections to prevent distortion of the lower sections within the stack
as to avoid crushing Lengths Witll projections such as branches and bends i1anges girths damper quadrauL should be loaded so as to
54
DW154 S1tciic(ltioll for Plastics Ductwork
85 Internal cleanliness of new ductwork The site storage of ductwork introduces the important cODsideration of maintaining the internal cleanliness of the ductwork R feren e should be made to HVCA documentshybull DWffM2 Guide to Good Practice - internal
Cleanliness of New Ductwork Installations If the above conditioDs can not be satisfied consideration should be given by tJle designer to amending the specification to include for Po t Installation Cleaning as covered by tJ1C HVCA documentshybull TRJ17 Guide to Good Practic - Cleanliness
of Ventilation Systems
APPE DIXC
Fi e Retardant inishes C1 Improvement in the fire retardancy of plastic
ducts can be achieved to varying degrees and is wholly dependent llPOll the surface coating laminating resin selected and construction specification adopted In some instances smoke emission is coILSidered equaUy with other speci fication requirernen ts of the materials resistance to ignition and bumjng It is therefore important for design rs to establ ish the clients and officers detailed requirements and not rely on a tbird party interpretation of fire resisting or fire retardant Where possible the specification should refer dir etly to compliance with a British or European Standard identifying the specific sections applicable There are various types of resin and mat rcLnforcements that can achieve a Class 1 surface spread of flame ratin o when tested according to BS476 Part 7 (1987) This test puts materials illto Class I - 4 in descending order of perfoDllance according to the rat and extent of flame spread over their surfac under standard beating conditions Materials should also be tested for flre propagarion to BS476 Part 6 (1989) Tbi tesr measures the amount and rate of heat evolved by the material when subjected to standard heating
conditions Test results are given as an index of Perfonnance (i) whicb is based on three sub indices (iJ (i1) (h) The higher the value of the Index of Performance (i) the greater is the material s contribution to fire growth The higher the value of the sub-index 0) rhe greater the ease of ignition aod flame spread The highest product performance classification as defined in Approved Document B of the Building Regulations is Class O This is acLlieved if a material surface of a composite ploduct i~ either a) composed throughout of materials of
limited combustibility or b) a Class I material which has a tlre
propagation index (i) of not more than 12 and sub-index (i l ) of nor more than 6
01 J Class 0 is not a cla$sif1cation identified in any British Standard test
There are resin system reported to be classified to Class O when tested to BS476 Pcl1S 6 and 7 however designers need to ensure that such sysrems can be applied to their proposed design In propriety resinmat system available the fabrication techniques and COITect application are critical to the integrity of the reinforcing and clas ificatiol1 For example in some systems the u e of a non-fire retardant gelcont on a fire retardant substrate would reduce the classification For further information see HVCA publication DW144 Appendix D
55
DW154 SplCijiClIliol1 for Plastics Ductwork
x Guidance otes For nspectmiddoton Servicing a d
Clean-ng Access Openings
D1 GE ERAL This appendix highlight in ummary fOI111
the acce considerations that hould be made by the design r iD terms of inspection servicing and cleaning Having considered the seop and the design of the dUCI work system relative to the guidelines outlined below the designer should clearly indicate which levels of acces should be incorporated into the manufacture of a new duct work system (See Table 14 and Note I b low it
D2 DESIGN CONSIDERATIONS
D21 In ptction and servicing requireshyments are set out in Section 15 of Lhis specification
D22 Cleaning requirements are set out in the HVCA pubUcation TRl7 Guide to Good Practice Clean Lines of Ventilation Systems and the guide tates The precise location ize and
type of access would be dependent on the type of ductwork cleaning inspection and te ting metbods to b adopted Care protection and standards of cleanliness prior LO cOlllmisionin o
are set out in th AV A publication DWITM2 Guide to Good Practice Internal Cleanliness of New Ductwork Installations and th guide state Wh re specific limits of cleanliness are required ductwork sball be cleaned after installation by a spcialist cleaning contractor It will b in the interests of tht desioner botb financially and practically to cunsider employing a specialist c1eauing contractor at tbe
outset of a contract to internally clean newly installed ductwork prior to bandover This approach would reali e the following benefit shyi) Tb actual numb r of cleaning
access panels could be detennined to suit the method of cleaning to be adopted (This may be 1 s than the maximum requiremen listed under Lev 13 of Table 14)
ii) Clear directions could b given to the ductwork contractor as to tJle size and location of cleaning access panels that are required to be fitted during the mauushyfaclunng pro s
iii) The specialist cleaning operation prior to commi ioning vould enable the cleaning contractor to verify the practical acee requirement for the future cleaning operation associated -vitb a regular maintenance programme
iv) A specialist cleaning operation prior to commissioning would allow the designer to omit from the speeilicatiolJ the DWrrM2 requirem nt for factory sealing protection wipe downs and capping-off
v) Specialist Ieall ill 0 to the measurable standard defin d in TR17 will allow an objective definition of cleanline to be achieved
Car ful consideration must be gIven by the designer to the practl aJ problems associated witb the manufacture and fitting of suitably si Led access panel on small cross section duct and on the circular faces of rouod and flat oval ducts in particular
D23 Special con ideration must be given by the de igner to the practical problems associated with gaining personnel access to heavily congested ceiling areas and multi-la red du twork systems This approach would avoid
56
DW154 Spfciication for Plastics Ductwork
the possibility of access panels being D3 ACCESS 0 IN-LINE EQUIPMENT incorporated into a ductwork system at the This appendix unly covers acc il1spection manufacturing stage that were later found in through the ductwork body adjacent to an item practice to be inaccessible for either ervicing of in-line equipment and not openings in the or cleaning activities equipment itself
able 14 Acce requirements for inspection servicing and cleaning
HVCA PUBLICATIO REFE NeE (uidtgt 10 Gund Prartict
Adjace t OW144 Cleanliness orVcnlillltio S~lcr~ fRjJ7
in-line LeyeJ 1 Level 2 Level 3 ite sequipment pcdionSen lcin~ Section d C1eaniJl( SUn(O)lnspc lion Palle ltk~m_n
2011 (minimum OiL Jubje-ct to duct ~zel (ft~ -Panels
Control Da pcrs One (inspection) 203 One 300 mm x 200 mm Both sid Fire Dampers One (sCTjdJl~) 20211 One 300 0101 x 200 mm One side HeatingCooling Coils One (inspedion) 20213 One 300 mm x 200 mm (lIpstream) Both sides Attenuators (rectangular) None required One 300 mm x 200 mm (downstream) Both sides Attenuators (circular) one retluired One 300 mm x 200 mm (downstream) One side Filter Sections One (inspection) 20212 one required Uoth sides Air Turn Vanes None requjred None required Both sides Changes of Direction None required one required One side In-Duct FansDevices One (inspection) 20213 None required Both sides l
1 In the absence of any indication by the designer only Level ) access will be jncorporated into a new ductwork system
2 Tbe panel izes associated with Lev lis I and 3 acee s ar e middottablished by reference to Section 20 of DW144 and Section 2 ofTRll7 respectively
57
DW154 Speclfifatio for Plastics Ductwork
pA XE
B-bliography Included in this Bibliography are technical pUblications which may be of interest (0 ductwork designers fabricators and erectors and to tho e in the heating ventilatlng air conditioning industries generally nquiric should be made of the relevant organisation at the address quoted Since its publication other addresse contained within 0V154 mav have changed and some pubJicalions may have been superseded
HEATING AND VENTILATING CONTRACTORS ASSOCIATION
4 Palace Court London W2 4JG Telephone 020-7229 2488 Fax 020-7727 9268
Orders fo FlY A Publications Old Matlsion House Eamont Bridge Penrith Cumbria CA 10 2BX (Telephone 01768 864771 Fax 01768 86718) Email hvcapoblicationshvwelfarecouk DWn 44 pe ilicatiun for sheet mctal duclwork (Iow- mediulllshy
and high-pressure) 1998) DWIl4 A practical guide to dUGI ork I akage te ting
(revised 2000) DWII54 Specification for plastic~ duct rk DW171 Guide to good Practice for kitchen venlibtion system DW191 Guide to good pracuce glass fibre ductwoJk DwrrMI Acceptance cheme for new products - Redangolar cro
joint classification Guide to good pra tice - Internal cleanliness of new ductwork installations Guide to good practice for the design for the Installation of lire and smoke uampers
J 1Other puhlications
HampV safely guide 5th edition JS2 Tool box talks JS5 Weldlng Safety booklet JSI9 afety facts bo klet Fact sheets 1-24 2nd edition JS2J COSHH manual volume 1 Advice on compliance with the
regulations 1521A CO I-rH manual volume 2 Asses mcnt h ets JS23 Ri k management manual TR3 BrazinltT and bronze welding of copper pipework cUld sheet
(I 976) TR5 Welding of carbon steel pipework (1980)
TR6 Guide to Good Practice for Site Pre sure Testing of Pipework (19 0) Guide to good practice cleanliness of ventilation Ylem
CHARTERED IN TITUTlO OF BUILDING SERVICES E G EERS Delta House 222 Balham High Road London SW12 9BS rTelephone 020-8675 5211 Fax 020-8675 5449) CIBSE Guide Volume A Design Data Volume B In tallatiol1 and quipment Data Volume C Reference Data
CommlssioniJIg Codes These Codes eover the preliminary checkS eUing to work and regulation of vanous catcgories 0 plan The Codes give a guide to design implications Series A Air Distnbution Systems Series B Boiler Plant
ri s C Automatic Conlrol ystems Cr1es R Refrigerating Sy terns
Sene iN Water Distribution Systems
Technkal Memonllda TM 4 Design Notes for the Middle East TM bull Design otes for Ductwork TM 13 Minimi iog lhc Risk of egiounaires Disease
Research Reports RROI95 Ventilation system hygiene - A review of published
infomlatioo on lhe occurrence and ffects of Olltamination Rl~02J95 Air-to-air heal rec v ry RR0395 rnfluen e of HV C on smoke detectors
ATlONAL ENI [ERING SPECIFICATION LfMITED Southgatc hamber 3739 Southgate Street Winchester S023 9EH (Telephone 01962 842058 Fax 01962 R(8982) BUfLDING S RVICES RESEARCH AND [ ORMATION ASSOCIATIO Old Bracknell Lane West Bracknell Berkshire RG 12 4AH (Telephone Brackl1eU (01344) 426511 Fax 01344 487 -7 )
Application Guides AGln4 De tglJing Vana~le Volume middotylans for KOOnl
iir Movement AG1I91 Commissioning of V Sylcms in Buildings 11 6194 Fire Dampers
B) 94 cntiJalion or KitcneTls
AG389 The Commls ionin of Air Systems In Buildmgs AH2192 Commissioning of Bern - A ~ode of Practice TN2417 I Fire Dampec il) Ventilating Ducl
BEATING VENTILATING A AIR CONDITION G MA UFACTURERS ASSOCIATIO (HEVAC) HEVAC Henley Road Medmenham Marlow Buck SU 2ER (Telephone 01491 578674 ox 01491 575024 Emoimiddot infofetacouk)
Publicatjons Air Diffusion Guide Guide to Air Handling Unit Leakage Testing Guide to Good Practice Air Handling Unit Real Room Acoustic ~ st Procedure Specification for the ertiiicatioll ofAir Filters Method of Test for Water Rejection PerfOnTlatce of Louvrcs Subjected 1(1
Simulated Rainfall Test Procedure for Acoustic Loo cs Specification 10 Floor GrilJes - Types Performan e and Method ofTest Specification for the Determination of the Collection Efficiency of SilJ1d
Trap Louvre Domestic Mechwlical Vclltllalion Systems with Heal Recovery Fan Application Guid
~an and Ouctwork Installation Guide Guide to Fan Noise and Vibration
pecification of Requirements for JallJral Smoke and Heal Exhausl Ventilators
pecification for Powered Smoke and Heat Exhaust Ventilators
Specification of Requirements for Smoke Curtains Design Gujue of Smoke Ventilation for Single Storey Lodustrilll Building~
Including those with Mezzanine Floor and IIi Racked Storage Warehou es - Issue 3
Guidance for the Design of Smoke entilation YSlem for Covered and Undergrollnd Car Parks - lssue 1
Application of SOloke Control Equipment and Syst m Guid to Good Practice - Isue J
58
DW154 Sp(C~tiifitiol for Plastics Ductwork
BRITISH STANDARDS INSTIT TION Sales Department 101 P ntooviLle Road London NI 9ND (felephone 020-78 1 78801)
CP 413 1973 Ducts for building ervices
SS 476 Fire tes on building matenals and lruc(ure
Part 4 19 4 Non-combustibility lest or materials
Part 6 I Fire propagation lest for materials
Part 7 1993 Surface spread of tlarnJ tesls for materia
Part 20 1987 Fir resistance of elements of construction
Part 21 1987 Fire r sistlUlce of loadbeanng elements of construction
Part 22 1987 Fhe istallceofllon-loadbearing elemcllts ofconsttuclion Part 23 1987 Contribution of componcnts to the fire resistance 0 a
structure
Part 24t987 Fire resi lance of wl1lilation ductl
SS 5588 nan 919 0 Fire Precautions III thc desIgn and OOSlnJ lion of buildings
S 729 1971 Hot dip galvanized oatiugs (or irOIl aod stcel articles
BS 1449 Steel plate sheet and Irip
Pan 11991 Carbon steel plate heel and strip Part 2 1983 Stainless steel plate sheer and strip
and
B middotENJOI49-2 996 BSEN 10149- 1991)
BSEN 10131 1992
BSEN22063 Sprayed metal coarings 1994 Protection of iron and steel by aluminium and zinc against
atmospheric cOlosion Irotectiotl of iron and ste I against corro ion and oxishydation at elevared temperatures
BS 353 1981 Glossary of lerms relnting to thermal insulation
BS ISO 1479 Self-tapplngscrewsandmetallicdri c crew
B -lSO 7049
1994
B 4800 1989 Painl colour for building purposes B 4848 l0 rolled structural steel sections
Part4 1972 Equal and unequal angles BS 5422 1990 Specification for the use of therm illuating matcriulS
SS 5720 1979 ode of practice for mechanical veutilating and air C 11shy
dirionin bull in building
l3S PR 12814-1 Bend resting for plasric welds
SS PR 12814-2 Tensile testing for plastic welds
SS PR 13067 Appro altesting for plastic welds
BS PR EN I 100-] Vi ual in pection ofplaslic welds
SHEET METAL AND AIR CONDITIONING CONTR-CTORS NATIONAL ASSOCIATION INC (SMACNA) Headquarters 420 I Lafayeue Center Drive Chanlilly Virginia 2051-1209
Mailing Address pa Box 221230 Cbantilly Virginilt120 153-1230
Telephone (703) 803-2980 Fax (703) 803-3732
Accepted IJJdustry Pl3Gtice for Industrial Duct Constnlelion 197 ) i-rchitecmral Sheet kwl Manual ([993)
Comractors Guide lor Modification 10 ooslruerion Colllraets 1993 Ducted Eleclric Heat Guide for ir Handling Ssrerns (1994)
En~rgy ollservatioD Guidelines (1984) Energy Recovery Equipment yslClllS (199l
Fibrou GIns Duct onS1ntClion Standards (1992)
Fire Smoke amp Radiation Damper In tall Guide for HVA Syst ms (1992) Guide t leel Stack 1(95)
HVA Air Duct Leakage Test Manual (19 ) HVA COlllmissioning lvlanual (1994)
H A Duct Construction Standards-Metal amp Flexible (1995) Addendum 01 (Nov 1997)
HVA Duct Systems Inspection Guide (1989)
HVA ySlems-Application (1986) nVAC ByternS-DLlct D ign (1990)
HVi Systems-Testing Adjusting amp Balancing (1993)
indoor Air Quality Manual (1993) tcheu quipment Fabrication Guidelmes (1990)
Managers Guide for elding (1993)
Rectangular Industrial Duct Cons1TUction Standards (19 0) Round Industrial Duct oustmction Standards (1977)
Sei mic Restraint Manual (1991) (wl Appendix E 1993) SMACNA Ma le Index ()fTechnical Publications (1995) Tbennoplnstic Duct CPY ) Construction Manual 1994)
DEPARTME OF THE ENVIRO MENT (Publications Centre) H Stationery Oflice 5 Nine Elms Lane London SWS 5DR
MampEJ 011972 Electrical in tallat1011 in buildings ( ew Editiou)
IampE 0319 Healing hot and cold wat r steam and gas losla1lations for buildings
M amp - No4 1970 Central heating and hot and cold ~ ateT in tallations for
dwelling
M amp ENo100 1971 Mechanical ventilation for building~
ASSOCIATION FOR SPECIALIST FIRE PROTECTlO As ociation House 235 Ash Road AJdershot Hampshire GUl2 4DD
Telephone OJ25221322 Fax 0 J252 333901
lublicalioos Fire Ratcd and moke Outlet Ducrwork An Industry Guide t Design and InSlalla lioll
HEALTH AND SAFETY EXEC TIVE Rose Court 2 Southwark Bridge London SEl 9HS Telephone 020-7717 6000
TWJ THE WELD G TlTUTE Abington Hall Abington Cambridge CB16AL Telepbone 0 J223 89162
Publication DatJ Oil w~ldll1g of lhermopla lics
59
DW154 wciiwlioll for Plastics Ductwork
A -=--DIX
Factors
Specific gravity shy pp = 091 approx UPVC = 14 approx
Some miscellaneous conversion factors
To convert
Length Inches to millimetres Feet to metres
Multiply by
2540 03048
To convert
Millimetres to inches Metres to feet
vIultiply by
003937 3281
Area Square inches to square millimetres 6452 Square millimetres to square inches 000155 Square feet to square metres 00929 Square metres to square feet 10764
Volume Cubic feet to cubic metres Cubic feet to litres Gallons (UK) to litres
002832 2831 4546
Cubic metres to cubic feet Litres to cubic feet Litres to gallons (UK)
35315 00353
022
Mass Ounces to grams Pounds to kiJograms Tons to tonnes
2835 04536
1016
Grams to ounces Kilograms to pounds Tonnes to tons
003527 2205
09842
Volume flow Cubic feet per minute to cubic Cubic metres per second to cubic
metres per second 0000472 feet per minute 2119 Cubic feet per mIDute to litres Litres per second to cubic feet
per second 04719 per minute 2119
Motion Feet per minute to metres per second 000508 Metres per second to feet per minute 197
Pressure Inches water gauge to millibars 2491 Inches wateJ- gauge to pascals (Pa) 2491 I Pa = I ewton per square metre = 10-2 millibars
60
Heating and Ventilating Contractors Association Esca House 34 Palace Court London W2 4JG
Tel 020 7313 4900
e-mail contact Itvcaorguk web site wwwhvcaorguk
Fax 020 7727 9268
DW154 Specificatiol for Plastics Ductwork
Flexible con ections
Fig 26 Flexible sleeve with clips (UPVC and PP)
--__ Flexible I eve
I
I
I CODn clioD to plant ~
Band clip
Fig27 Welded flexible sleeve (UPVC only)
Plastic)sed PVC slceve ~-- onll11uo1sly welded
onrreclion to planl ~
Fig28 Flanged flexible connection (UPVC and P )
t sp dally moulded flexible flanged connCClitlll
boil
C)nneclion to plant ~
26
DW154 Specificotiol for Plastics Ductwork
182 LOClt1tion Flexible joint are typicltllly lIsed at building expansion joint and fan inletsoutlets Any others required should be indicated on the de ign drawings Care should be taken to maintain alignment across jointsconnections
183 Length Flexible Jomts shall be kept as short as pra middottieable above a minimum eft ctive length of SO mm In no ca e shall a flexible joint exceed 250 mm in lengtb
184 Connections to rectang a ducts With flanged rectangular connections Ule tlexible material shall be held in pLace with flat pIa tic strip of not less U1an 6 mm thick ltlttached to the flanges using uitabJe fixings The more heavy weight type of fleAible mateLial may also be obtained formed into a channel ection with corners fitted to give a neat air tight j int For pigot connections the Be ible material shall b held in place with flat pIa tic trips n t less than 6 mm thick
t 85 Connections to circular ducts With tlanged circular connections the flexibl material shall be held in place with flat plastic backing strips or proprietary clip bands with screw or toggle fast ners
186 Welded flexible connections (Rectangular and Circular) Where the parent and llexibl material are from imilar ba ed products they can be joined to the duct u ing the welding method described in Section 823
19 PROTECT VE FINISHES
191 nles otherwise stated all ductwork shall be mallllfactured in mat fial as pecified in tbis specification Any special coatingpaint fmishes to be provid d by the duct work contractor sball be advisd by th de igner
20 CONNECTIONS TO BUILDING OPENINGS
201 Fanning and finishing building op nings are not the repoJlsibjlity of the duftw( rk contractor and the note that follow are for guidance purpo e only
2011 Openings in brick block or concrete walls shall have inset frames to provide a suitable means of fixing grille louver masking flanges or the tlanged ends of ductwork The illset frames shall be conslnlcted to maintain the structural int grity of the wlll and where applicable cavities shall be suitably lined
2012 Openin s in dry linino partItIons shall have inset frames a 2011
2013 Openjngs in cladding walls and roofs shall have flaoged leevesframes to provide a suitable means of fixing a 2011
2014 Horizontal and vertical opening xposed to oLltside atmo phere hall
be provided with a suitable weathering fini h at the external face especially where profiled cladding is used
2015 Timber framed op nings are not permitted In fj re compart ment barriers
202 Ductwork connections to building openings hall have a flange of suitable profile to permit practical fixing to the openillg frame In selecting the profile consideration shall be given to Tabl~s 2 and 10 in this specitication relating to duct ize and rating Gasket strip or sealant shall be ltlpplied between the tJaoge and building op ning frame
21 DISCHARGEEXHAUST TERMINAL
21 Tbese shall be vertical open ended and designed to meet and comply with current r gularions on contaminated flue The designer hall ensure that the de ign and perf rmance i suitable for its intended purpose Examples of some typical terminal designs are SbOiD in Figbull 102 10 bull 104 amp 105
27
DW154 SpedjimioTl for Plastics Ductwork
22 THERMAL INSULATION
221 The provision and application of thermal insulation to ductwork is not the responsibility of the ductwork contractor
222 Where ductwork is required to be preshyinsulated the specification should be agreed with tbe designer
223 Where the temperature of the air within the duct promotes condensation on the exterior surface of the duct and cause moisture penetration througb the thermal insulation vapour scaling may be required and in this case the most important requirement is to limit penetration of the seal
The extent of any vapour sealing of ductwork thermal insulation and the support method to be u ed must be clearly pecitled in advance by the designer
224 For detailed information on the thermal insulation of ductwork reference should be made to BS 5422 1990 which covers the specification for thermal insulation materials on pipes ductwork and equipment (in the temperature range -40degC to +700degC) and BS 5970 1992 which is a Code of Practic for Thermal Insulation of Pipework and Equipment (in the temperature range -lOOdegC to +870degC)
23 FIRE RETARDANT FINISHES ON PLAST C DUCTWORK
231 The designer should note tbat ductwork constructed to DW154 has no teted fire rating or information see Appendix C
24 REINFORCEMENT OF DUCTS WITH GRP LAMINATE
241 General Where ductwork is required in larg T izes than are covered by Tables 2 4 6 amp 7 or with the increased strength sometimes necessary for industrial use external reinforcement is normally pwvided by applicatioD of glass fibreresin laminate
GRP systems will bond satisfactorily with standard UPVC sheet but for pp it is
nece sary to use a specially prepared sheet with a glass fabric backing incorporated dOling manufactllfe
The detailed techniques of fabrication using GRP are outside the scope of this speci lcation but the following notes are offered for guidance of ductwork fabricators
242 Materials
2421 Quality The laminate is made up of polyester resin complying with BS 3532 and glass fibre complying with BS 3496 or BS 3749 The nominal ratio of resin to glass fibre should be 7030 by weight
2422 Minimum properties The laminate shall comply with the followiog mini mum pbysical properties
Tensile strength - 70 MNm Tensile modulus - 7 Gl m Flexural strength - 140 M Im Bond strength (hetween laminate and substrate Not less than 7MNm Bmcol hardnes Not le s than manufacturers specification
The GRP reinforcement educe the expansion of the parent material but the resultant stre ses arc well within rhe strength of the bond However the Iinear thermal expansion curve shown in Figs 34 amp 35 will serve as a guide
Surface resistivity electrkal propcltles and acoustical propertie are similar to the relevanl unreinforced materials The fire retarding properties of GRP may be improved by the use of specialisl laminating resin
2423 Forms available GRP Laminate should be built up from the separate materials ie resin aod glass fibre in the form of chopped
I strand mat or spray ravings
28
DW154 Spcification for Plastics Ductwork
2424 Workshop conditions Polyester resuls are sensItIve to lmperature and the workshop hould b maintained at a temperature of herween 20deg and 25degC HiOh relative humidities and damp onditions should be avoided A good rate of air change must be pro icled pJeferably by m chanical ventilation
2425 Storage of materials Resin and urin o agents shouJd be stored in dark cool condirions away from the working area and in confonnit with statutor requireshyments for tJle middottorage of flarmnable liquid Because of Ule Limited torage lif of the unmixed resin and curing a eot mal lials ~hould be ch eked before use to enLlfe that they are within the manufacturer pe ified sh If life (usually ix month from the dm of manufacrure)
Glass fi re should be stored separately und r clean dry conditions
243 Surface preparafon
2431 UPVC To achieve the specified bond strengtll the urface to which the GRP is applied mut first be thoroughly cleaned and then etched either by mechanical means or by the use of a suitable solvent
2432 pp with glass fabric backing To achieve the specified bond middottrength the fabric backing must be thoroughly impregnated Witll resin
244 Mixing the materials for use The re in 1 a three part mix compri lng base I sin hardener and accelerator The manufactur rs pecj[ied proportions are critical and th llUxmg sequenc pecified must be meticulously foUowed
The resin has a very limited life after mixing and before u e It is dependent on the characteri tics and bulk of th resin the alllount of hardener the degree and method of acceleration and the workshop onditions
245 Methods of application
2451 General The mixed resin may be applied by hand or b pray c1epoition The operation must b completed within the gel time of th y tern and tbe laminat fully cOI1olidated to achi v the phy ieal properties pecified
2452 Hand lay-up The duct surface i coated by hand with resin Llsing a brush and a mar of gla fibp orked in until full consolidation achieved Th proc is repeated untiJ th requird thicknes i obtained
2453 Spray depo Won The duct surface is coated WiUl re in by spray gun with the chopped glass roving added through a separate nozzle The full thickne i obtain d in layer with con olidation of each layer by hand roller
246 Construction
2461 General M ini mum COllst ructional requireshyments are pe itied ill Tabl 10 for rectangular and Table 1J for circular dUClS
2462 Joints and stiffeners Fig 29 30 31 32 amp 33 hoI TOSS
joint and tiffener for reinforced UPVC and PBPP duct
247 Worki g practices The fabrication of ductwork pecifiecl ill thi document i not affected by the addition of GRP
29
DW154 SfJcdJicatiOt for Plastics Ductwork
Table 10 Minimum constructional requirements shy
Longer Side Minimum Sheet Thicknes and
GRP Reinforcement
UPVC FBIPP 1 2 3
mm mm mm Up to 1000 3 plus 3 plus
06 kgm2 06 kgOIl GRP GRP
1001 to 2250 45 plus 3 plus 06 kgm 12 kgm
GRP GRP
2251 to 3000 45 plus 6 plus 12 kgm 12 kgm
GRP GRP
Cross Joints
UPVCFBPP 4
mm socket amp spigot
as Fig 30 or flanged as Fig 29
75 x 9 flange welded on both sides as Fig 29
75 x 9 tlange welded on both sides as Fig 29
rectangular GRP reinforced ducts
SlifTeners Maximum Spacing Between
JointsSljffeners UPVCIFBIPP UPVCFBPP
5 6 mm mm
75 x 9 flat 800 as Fig 31 or
50 x 50 x 5 plastic or MS inverted angle as Fig 32
or tormer as Fig 33
75 x 9 flat 600 as Fig 31 or
50 x 50 x 5 plastic or MS inverted angle as Fig 32
or former as Fig 33
75 x 9 flat 600+shyas Fig 31 or 50 x 50 x 5 plastic
or MS inverted angle as Fig 32
or former as Fig 33
Note 1 On rectangular duct up to 400 mm longer side no stiffeners are required 2 Applies to Tables 10 amp I I For COlJstructional operating temperature limits refer to Part 2 clause 5A 3 Tables 10 amp II apply to all pres ure classes up lo ]500 Pa
Table 11
Diameter
1 III
lJp to 1000
1001 to 1750
1751 to 2500
Minimum Sheet Thickness and
GRP Reinforcement
UPVC FBPP 2 3
mm mm 3 plus 3 plus
06 kgm 06 kgm GRP GRP
45 plus 3 plus 06 kgm2 18 kgm
GRP GRP
6 plus 6 plus 12 kglm2 18 kgm1
GRP GRP
Cross Joints
UPVCFBPP 4 III
socket amp spigot as Fig 30 or flaoged as Fig 29
75 x 9 flange welded on both sides as Fig 29
75 x 9 flange welded 00
both sides as Fi 29
inforced ducts
Maximum Spacing Between
JointsStiffeners UPVCIFBPP
6 mm 2400
800
600
Stiffencrs
UPVCFBPP 5
mm 50 x 9 flat as Fig 31
75 x 9 flat as Fig 31 or former as Fig 33 75 x 9 tlat as Fig 31 or t()rmer as Fi 33
ote On extruded tube tip to 600mm diameter no stiffenergt are required
30
DW154 Specificatioll for Plastics Ductwork
G - Cross joints and tiffeners
Fig 29 Flange Joint Fig32 Stiffener shy inverted angle
M artiPfCuQkbdd erttpObri) Wl111 RP tlddtlt
_- GRPloliu] lh~
Fig 30 Socket and spigot joint Fig33 Stiffener shy use of former
Fig 31 Stiffener Flat
I Pv FlPP ~ ~lmJaDUA1) d
OMrlQ rrnall 1( tQlS
25 STANDARD COMPONENT DRAWINGS AND ABBREVIATIONS
251 The illustrations in this section not only highlight where applicable geometric limjtations for the de ign and manufacture or ductwork components but also recommend
standard drawing representation terminology and abbreviations for both duetwork components and some of the more commonly used ancillaryplant items
252 Designers and surveyors should note that bills of quantities should provide a full description
3)
---
v
DW154 Spcc(fim(ml for Plastics Ductwork
Fig 34 Linear Thermal Expansion
u c 0 N ro 0)
b 0)
S
sect0
5 oS cl) 0)
~
on ~ ltl
c U
-30 -20 -10 0 10 20 30 40 50 60 70 80 90 TEMPRATURE C
~ V
-
~~c_ ~
~V
V ~
-7 ~
-- ~V ----
v
-6
+14
+12
+10
+8
+6
+4
+2
0
-2
--4
ig 35 Typical Design Stress tor UPVC and P
7
6
r shy 5E
-c E----0 4t) VJ 0)
ci5 0Jl 3
~
0)
Cl
2
1
o
UPVC
1
000
1
1
pp
- r-- shy r----- shy - t--shy I
__0
-30 -20 -10 0 10 20 30 40 50 60 70 80 90 TEMPERATURE C C
Note Figso 14 amp 35 shaded area refers to GRP reinforced duct
32
DW154 Speciicfltirm for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - REC ~NGULAR
Splilt~r Posilion W-mm pliucr
A B c 40]--QOO 1 W - -
601-1000 1 W4 Wf2 -
1001-1800 3 WI W3 W2
FIG DRAWING DETAfiS
tU]36 ATI Straight Duct with socket and spigol joint
rn [037 Straight Duct with flanged joints
[I []38 Straight Duct with flanged joints
rkJ Short Radius Bend
39 Applies to any augl and for duct up to 400 n11n wide
Minimum (I1m31 radills = 100 mm
Medium Radius Bend (a illustrated)
[kJ Applies to any angle
40 Long Radiu Bend Similar but radius = W
Throlll radius = W2 Applies to any angle
- Short Radius Bend with plitlers
I -shy -shy u co - t lt Li--_ 41 t 0 ~ I I I
~ I
L 1W
Minimum waal radius = 100 mm Splitters not required in bend angle less than 45deg
42 QJ1 Square Bend with turning vanes ij
3
DW154 SP(L~ficatioll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - RECTANGULAR
FIG DRAWl G DETADS
43
~
I v
L L Radius Tee with internal deflectors
44
~ Radiussed Twin Bend
45
Imiddot
er Swept Branch
46 U-
Sqoare Tee with Turning Vanes
47
~ f
Breeches Piece
48 0 y l Piece
34
DW154 Specificatioll for Plastics Ductwork
STANDARD COMPONENT RAWINGS - ECTANGULAR
55
54
51
50
53
52
49
FIG
~MX
RAWlNG
DmiddotMAX
EfjMAX
Minimum throat rndius = 100 mm
Rectangular shy Round Transformatioll
Eccentric Taper 225deg max in either plane Spliller are required for angles greater than 225deg and hould bi eet the angle between any side and duct centreline
DETATLS
Angled Offset
OUset Taper Splitters are required for angle greater than 22 0
and shoold bi eet the angl between any side and dUCI centrelinc
Mitred Offset
Concentrk Taper 2250 max in ither plane SpUtters are required for angle greater than 225deg and should bisect the angle between any side and duel c ntreline
Radiussed Offset
35
DW154 Splcilcuthm for Plastics Ductwork
STANDARD COMPONENT DRAWINGS ~ RECTANGU AR
Branch ducl DimCllsions widlh (W) (A)
urnl mm up lO 200 75
300 100 400 125 600 150
Ocr 600 200
FIG DRAWlNG DETAILS
56 poundplusmni~~ Rectan~lar - Flat Oval Transformation
57 [ Square Branch
58 er Angled Branch
Branch dUCI Dimensions wfdth (W) (A)
[- mm mm59 3shy Shoe Branch Up (0 200 75
--shy AIshy + 300 100
400 125
450 MAX 600 150
Over 600 200
Branch duct DimensIOn
rP X width (W) A)
60 - 1--shy _
~ mm mm
Bell Mouth Branch pto 200 75 300 100 t 400 125
600 150 Over 600 200
0=0 61 -
~ Bell Mouth
- shy T 4-5deg M x
--I 1-shy
TJ
62 X I ] I
Tele-scopic Joint I Illustrated with flangeL
X63
SBD Single Bladed Damper
36
---
DW154 Spedicatioll for Plastics Ductwork
STANDARD OMPONENT DRAWINGS - RECTANGULAR
DRAWING DETAILSFIG
64 on-Return DamperNRD shyshy
shyXbull
Multi-Leaf Damper Can be piggoted or flanged oppo cd or parallel blade
Alternative controls areshy
q p [gtshy
J HD65 Hand
~MD otori ed
PO Pneumalic
L-lt
l 13G 66 Blast Gate DamperX X
FireSmoke DampersSleeves
211r Ratinggtshy----
L_-
---
----
r----
Ir-- shy
IL- _-l
2hr
With i tallation frame
67 41 r Rating
4hr
Smoke damper SD
Intumc cent Sleeve L-d
37
DW154 Specijicutiolt for Plastics Ductwork
FIG
68
69
70
71
STANDARD COMPONET DRAWINGS shy REC ANGULAR
DRAVING DETAILS
gtshy Access Openings
AP 6 Access Panel - Rerno able
w [ ~ Access Door - Hinged
I ~le Inspection Cover
le -I reg -lt
~X X Flexible Connection
~ Drop Cheeked Radiussed Twin Bend
U Drop Cheek Bend
I
72 Air Flow SymbolX
38
DW154 Specifim[ioll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - ECTANGULAR
FIG DRAWING DETAILS
73
74
75
76
77
Q
Q
rp---t
~
V- I Ir---I
JL --11
THE ABOVE DETAILS TYPICAL PLENUM
Air Terminal Plenums
Plenum with side connection
Plenum with top connection
Cover plate with connection
Special plenum with connection
elescopic conn ction in direction of air flow
39
DW154 SpecijicotiOll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG
78
79
80
81
DRAWING
-23~---pound3-(MALE) (FEMAJE)
-t=j--_j(--d-shy
--L
~ THROAT RADI S= D AS T NDARD
e ~
THROAT Rjf)lU = D A MU)
DETAILS
Straight Duct With male and female connectors
Straight Duct With flange joint and slip joint
Bend MouldedIFormed Applies to any angle ego 30deg45deg60deg90deg Medium radius bend as illustrated Long radius similar but throat radius 0
Segmented Bend 90deg four section minjmum as illustrated
Other Angles 60deg = 3 sections 45deg = 3 sections 30deg = 2 sections
I
i
40 shy
DW154 Speciicafinll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG DRAWING DETAlLS
82 Segmented Twin Bend Radius = D2 max
May also be fabricated from tube
83 Equal Tee MouldedIFormed
84 -~ 1in Bend MouldedIFormed
85 Taper Concentric 1 0 as iUu trated Eccentric 30deg iJJcLuded angle
86 Short Taper
41
DW154 SpcUicatol1 for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG DRAWING DETAILS
87 30 max Offset
Angle Branch
Bran h dUCI Dimcnsions dia (D) lA)
Shoe Branch mm mm 88 Cl
Off rectanguJur Up 10 200 75 lOO 10 400 125
- 00 150 Over 600 200
Bl1IllCh duct DimenlOns din (D) (A
~-$a-Conical Branch mm mm
89 Also acceptable with Up 10 200 r
full conical surface 300 10
400 125
END VrE -shy 600 150 Over 600 200
90
m 75
100 12 150 200
mm Up to 200
_ 300 400
600 Over 600
iUtred Branch
Shoe Branch
J-L----U ~ Bell oulh Branch
ENDV1EW
93
92
91
42
DW154 Specificatiol for Plastics Ductwork
STANDARD OMPONENT DRAWINGS - CIRCULAR
FIG
94
DRAW G
I
~ 30deg 090deg
Breeches Piece
DETAILS
95 amp-----~ Blank End
~-----p Multi-Leaf Damper Can be piggolcd or fianged opposed or parallel blade
Alternative controls areshyri=-+- L-T~
I
---
LT~
I r- -
-+1
J HO Hand96
bMD Molori cd
PD Pneumatic
tl-shy bull
Single Bladed Damper 97 ~ saD
on-Return Damper Vertical application only 98 m~D
43
DW154 Sf1tcificatioll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG
99
100
101
102
DRAWING
$ I-
2hr
1 4hr
SD
~v I I
CO TINENTAL COWL
DETAILS
Iris Damper
Fi reS moke Dam persSleeves
2hr Ratillg
With installation frame
4br Rating
Smoke damper
Intumescent Sleeve
Access Openings
Access panel - removable
Access door shy hinged
fnspection cover
Discharge Continental Cowl
44
DW154 Sp(Cii(ltJll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
DRAWINGltIC DETAns
-
I
I
~
I I I High Velocity Discharge Terminal 103 I
I
I I
J I I 1 ~--
Offset Stack Discbarge Terminal 104 1
~ I e --(-
I
N
I
I
I~
I I Vertical Oischarge with Weather Cowl 105 I
--1--1 I
I
GAPI I
RTl AL DISC) lARGE WITH W ATIIER COWL
45
DW154 SpecUicatoll for Plastics Ductwork
STANDARD COMPONE T DRAWINGS - PLA TEQUIPMENTIMISCELLANEOU
FIG DRAWING DETAILS
106 ~~~ Rectangular Attenuator
107 ~- Circular Attenuator
108
~ Beod Attenuator
109 J ~(f) Heating Coil
110 J ftte Cooling Coil
III Jc[ Electric Heating Coil
112 X F
Humidifier
113 [H XX Axial Fan
114 ~fB1famp Noo-standard Ductwork Cross hntchillg (of any separate type) indicates by reference to a key any non DVil54 ductwork system
115 2llIIIIJIIIIIll Flexible Ductwork
46
DW154 SJeCUicll(iol1 for Plastics Ductwork
TABLE 12 - STANDARD ABBREVIAT ONS
ABBREVIATION FLL
AD Acces Door
AFF Axial Flow Fan
AHU Air Handling nit
All Aluminium
AP Acess Panel
AT Attenuator
AV Air enninal Unit
BE 81ank nd
BQ Blast ate Damper
CC Cooling Coil
CF Centrifugal Fan
CTA Cross alk Attenuator
CVU Constant Volume Unit
DP Drain Point
EEC Electric Heating Coil
El Expansion Joint
FAl Fresh Air Inlet
FA From Above
FB From Belo
fBPP Fabric Backed Polypropyl-ne Sheet
Flexle Flexible Connection
lexfD Flexible Du t
C False Ceiling CO an oil Unit
fD Fire Damper
FFL Finished Floor Level
FJ Flanged Joint
FOAM Rigid Polyurethane Self xtinguishing Foam
FOB Flat on Bottom
FOT Flat on Top
GAM Galvanised after ManufacttrJc
GRP Glass Reinforced Plastic
GSS Galvanised Sheet Steel
HC Heating oil
HD and controlled Damper
HH Hand Hole
HL High Level
HVD High Velocity Discharge
IC Inspection Cover
ID lri Damper
IFS Intumescent Fircleevc
47
DW154 Specification for Plastics Ductwork
TABLE 12 - STANDAR ABBREVIATION CONTINUED
ABBREVIATION
IU
L
tv1D
MS
NRD NTS
OBO
OE
PHD
PD
PP
PP
PRD
PVC
RFC
RSC
R
SBO
SO
S1 TST
SSL
TA
TB
TO TJ
TP
TV
TV
OS
UPVC
S
V
VAV
50 RSA
FULL
Induction Unit
Low Level
Motor controlled Damper
Mjld Steel
on Return Damper
at to cale
Opposed Blade Damper
Open End
Parallel Blade Damper
Pneumatic controlled Damper
Polypropylene
Self xtinguishing Polypropylene
Pressure Relief Damper
Polyvinyl Chloride
Rolled Form Chamlel
Rolled Steel Channel
R fUnit
Singl Blade Damper
Smoke Damper
Slip Joint
Stainl t el
tructural Slab Level
To Ab vc
To Blow
Top Down (In Direction of Flow)
Telescopic Joint
Test Point
TU111iog Vane
Top Up (In Direction of Flo )
Voles Otherwise Stated
Unpl3sticisecl Polyvinyl Chloride
Underside
Ultra Violet Light
Variable Air Volume
Rolled Steel Angle (Vith Size)
48
DW154 SJeriiflllioll for Plastics Ductwork
A2 DUCT PRESSUREAPPE DXA Ductwork con truct d to DWIl54 will bebullbullbullbullbullbullbullbullbullbullbullbullbullbull
Air Leakage From Ductwork To be read in conjunction with DW143 A practical guide to Ductwork Leakage Testing
CAUTION As highlighted ill both this docul1lenr and DW14 I lot ellough emphasis can be placed 01 the fact that except for high pressure class C the much more stringent ductwork constructional standard brolght about b the general acceptance of DW154 have irtlally negated the requirement for leakage-testing It is essential lO realise lhat except where it is mandatory this doclllllelll is nOl an endors ~lIlent of the rourine testing of ducts bllt purely a guide to outline the procedures for cononnity with the air leakage limits ill Table l Where the specified methods of assembly and
A3sealing of dlcls are u ed a vi ual inspection wil ordinarily sl~fll e for ver(iatioll of a well engineered and a ceptahfy airtight COl1strucrioll WHERE NOT MANDATORY DUCT LEAKAGE TESTING IS GENERALLY AN UNJUSTIFIED AND SUBSTANTIAL EXPENSE
A1 INTRODUCTION L akage from ducted air distribution systems is an Lmportant consideration in the design and operation of ventilatjon and air conditioning middotystems A ductviork t)ystem tbat ba limited air leakag within defiucd limits wiH cnsUft
that tile design characteristics of the sytem can be maintained It wilJ also ensure that energy and operatLonal cosb are maintained at optimum levels DucLwork constlucted and Ulstalled in accordance with DW154 should minimise a level of air leakage that it) appropriate to tll operating static air pre sur in tile system
A4However it is recouuised that tbe environment in wtJich middotystems are installed is not always conducive to achieving a predictable level of quality in term of system ajr leakage and it is therefore accepted that designer may sometimes require tlle ystem to be tested in part or in total It should be ecogni ed that the testing of duct systems add a ignificant cost to the installation and incur some extra tjm within the programme (Se 47 and 64 re mandatory te-sting)
manufactured to a structural standard that is compatible with the system operating pressure There are three classes of duct con truction to eorre pond with the three pre ure clas meations Class A Lo pressure ducts suita le for a maximum positive operating pressure of 500 Pascal and a maximum negative pressure of -500 Pascals Class B IVledium pressure ductmiddot suitable for a rnaxilnuJJl positive operafjn o pressure of 1000 Pascals and a maxllnum negative pre sure of -750 Pa cal Class C High pre sure ducts suitable for a maximum po ilive operating pressur of 2000 Pa cals and a maximum negativ pres ur of -750 Paltcals
LEAKAGE FROM DUCTWORK Leakao-e front pia tic air ducts occur at the joint~ and is therefore proportional to the total surface area orthe du twork in th system Tb level of leakage i imilarly related to tIle air pres ure in th du t system and whilst there LS n precis formula for calculating the level of air los it i generally accepted that leakage will increase in proportjon to pressure to rbe pOvver of 065 The effect of air leakage from high pressure velocit ductwork is critical tn terms of system perfomlan dege energy consumption and the risk of high frequency noise as ociated with leakage These problems are le critical with medium pressure 10 ity systems but should be con idered Low pres mevelocity ducts present the lowe~t
ri k in tenn of tbe effect of leakage on the operation of the s stern
SYSTEM LEAKAGE LOSS As there i no di ct relatLonship between th volume of air conv yed and the surface area f the ductwork sy tern required to match the building configuratmn it is difficult to express air leakage a a percentage of total air volume Similarly the operating pressure will vary throughollt lh 3 system and a leakage is related to pre me the calculations ar comple However it is generally ac epted tbat in typical good quaJjty systems the leakage from
49
DW154 Specificatioll for Plastics Ductwork
each class of duct llnd r operating condition will be io the region of CIa S A low pressure 6 Clas B medium pres un 3 Clas C high pressure 2
A5 SPECIFYING AIR LEAKAGE TESTING Re peeting both the co -t and programme implications a sociated with te ling du 1 for leakage the designer may for example indicate that a particular system is te ted as follow
a) High pressure ducts - all tested b) Medium pr ssure duets - 10 of the
ductwork shall be s eet d at random and tested
c) Low pre sure - unte ed In any case where a random te t i elected for medium pre sure ductmiddot the followin c1au~e is suggested for inclusion by the de ign r
The designer hall elect at random a maxirnwlI of 10 of the dUCl system to bt tested for air leakage The duct hall be tested af the pressure recommended in Table J3 for the assifi atiol for the ectiol1 of the ductwork that is to be tested The tests shall be carried Ollt as the work proceeds and prior to the application of thermal insulation In the event of test failure of the randomlY selected section the designer shall have The right to select two La1her e tiolls at random for resting Where succes ive failures are identified there shall be a Tight to require rhl COl11raCWr 10 apply remedial attention to the complete ductwork system Th contractor shall provide documented eviden e of the calculalions used to arrive (1
the allowable 10 I for the section to be tested and the client or his agent shall willess and sign the results of the test
able 13 Air leakage rates
Maximum leakage of duct work Static
prcssUft Low-pressure edium-prc-sure I Iigh-prebull me diJfercntial Class A Class B Class C
1 2 J 4 Pa Litres per second per quare metre of surface area 100 054 018 ZOO 084 028 300 110 037 400 132 044 500 153 051 600 058 019 700 064 021 800 069 023 900 075 025
1000 080 027 1100 1200 1300 1400 1500
029 030 032 033 035
1600 1700 1800 1900 2000
036 038 039 040 042
Note Recommend d mean test presures are highlighted iD bold type with the actual selection being left to tll test operator
50
DW154 Sfeeiieaioll for Plastics Ductwork
A9
A10
and air leakage classification for the y em under test
DESIGNERS CALCULATIONS The designer can middotaJculate with reasonable accuracy the predicted total loss from a ystem by
a) Calculating the operatin presure in each ection of the sy tern
b) Calculating the surface area of the ductwork in each correspondin pre lire s ction
c) Calulating the allowabl~ los at the operating pressure for each ection of the system (see table 13 for allowable leakage figures)
VARIABLE PRESSUR S IN SYSTEMS De igner can achieve significant co t saving by matchina operating pressures throughout the system to constmctional standard and appropriate air leakage testing eO the practice of specifying construction tandards for whole duct sy tems based on fan discharge pre sure may incur unnece sary costs on a project For example ome large sy terns ould well be classiC ed for I akage limits as follows
Plant room risers CJas C Main floor distriblltJou CIa B Low pre sure outlets Cla A
A6 SPECIAL CASES There may be ~itLlations on a project where circumstance dictate thal pecial consideration be given to containing air loss s eg a long mn of duclwork may incur a di -proportjonate level of air 10 s In ca es such as thi example the designer can specify an improved tandard of airtighmess ie 80 of alJo~able 10 s for la B Ju ts The designer sbould not specif a CIa C t sI at CIa s C pressure for a CIa s B ducl
A7 SUGG S ED RANGE OF TES ING
A8 TESTING OF PLANT ITEMS Items of inline pJant (eg Fig 106 to 115) will not normaUy be included in an air I akage test The dllctwork contractor may indud such itelllS in tbe te t jf rh quipm ot has a certificate of COnfOlnlity for Ihe pres ure clas
bull High pressure duct bull Medium pre sure ducts bull Low pre sur ducts bull Exposed extract syst ID bull Ceiling void extract
systems bull Secondary ducts from
VAV or fan coil units bull Flexjble duct bull Final connections and
branches to grille and diffusers
100 test See A5 Untested UDt sted
Untested
Untested Untested
Untested
SI
i
DW154 SJecijicafion for Plastics Ductwork
ig 116 Permitted leakage at various pressures
Leakage in litres per second per square metre duct surface area
Vgt
o ltgt 0 ltgt N
ltgt Cgt
0 0 cc
0 0
~
g =
g ~
c 0
J
ltgt 0 I
~ ] tn
ltgt ltgt
In ol
~ 0 ~ 8 ~
~
c ltgt ltgt
~ CJ
~ ~ ~ ~ 8
0shyij
~ ~ ~ t
ltgt ltgt 00
l
~
~ Q
c C
~ rshy
e ltgt
I 1
I Cgt ltgtv
c Co ~
~~ ~ 10
I
0 Cgt
fJshyq 410 ) 1 ltgt
ltgt N
~ shy ltgt ltgt
~ I 1
c
52
DW154 Specificatio for Plastics Ductwork
Example of a completed test sheet Test No
General
Name of job N~ jC43Pt(r2lef Building Repound ~(~~0
Part 1 - Physical details
a Section of duct work to be tested ~(diffPIfff~el1f3rd Floor
b Drawing Number g91~~ c ssure aSSJ L atlOn V~Jl~IRfYgtg~~lPre Cl T Class C
d Test static pressure -(9 raErq~ ~~~~-~~J~~~ ~~ ~~~~ll
Leakaoe factor 9~-tre3$ecMz I OM REFTOTABLE 13)e b bullbullbullbullbullbullbull
f Surface area of duct under test Q~tJJItetre$ CPROMCALCU TIO BELOW)bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull ampampamp bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull
g ]Vlaxi mum permitted leakage -~ (~i~~0 ~~r~~ ~~~l-~-11~ ~~~Q
Part 2 - Test particulars
a Duct static pressure reading 9QFt~q~ ~ middot~~~1 ~~
b Manufacturer and type of liow measuring d vice (-~~~cJ~Y-9Q7EYg c Range of measurement of now measuring device QtP)OQ~(e~~~0I~~~~1~I~ ~~~~~~W~
d Reading of flm measurin o device pmiddot IFROM RIO)ftscag ~
I (DERlVED [ROM CHART SUPPUED WITH RIG US 0 ud)1e Interpreted air flow leakage rate ~(~~~f~~~ (~l~~~~~~~~~~~~~~~~~I
f Duration ~~~~~norn~allY l~ lnil1Ut~~d~~~ it1~ W~ Date of test ~(lITled ut by Wltll s ed by ~ ~
(~lJ MIJLrr) (Si~rrfltJUYJ
Printed Name 1~g0f~ Printed Name ~~Y~9~ and Company 7jl~~~~~( UJd CompanY AB COII$Itallt8
Width and depth or diameter
Periphery ength Area
millimetreS millimetres metre qL1are metre
800 x 750 3100 1755 5440
600 x 650 2500 557 1193
300 x 300 1200 120 144
305 din 958 700 670
250 dia 785 450 353
TOTAL 8000
53
DW154 Specijilarion for Plastics Ductwork
pA XB
Guida ce No es For he ransport Handling and
Storage of uctwork
avoid damage to adjacent duct panels In somc ca es particularly on con acts calling f r repetitive sizes the use of timber jigs and spacers may be justified Where reduced bulk and greater protection are major factor such as consignments for export transporting ductwork in L shape sections may justify the increa ed ite as embly co ts
It is recommended that before a contract is finalised that consideration is given to the subject of site acces material handling and storage as tbcy havgt a strong influence on the cost efficiency of the overall activity of ductwOlk installation
B3 Handling To minilnise th risk of damage duct sections should be clearly identified and deliveries to site should be closely linked to the installation programme so as to avoid accumulation of
B1 Storage and Handling of Ra Material Material should be stored in suitably designed racking out of direct unJight Where possible the e racks should be metal to earth Edges of cut she t may be harp and protective gloves are advised Wearing teel toe-capped boots is recommended Most pIa tic sheet is manufactured with smootb mfaces andor is suppLied with protective coating Care must be taken to prevent accidental lippag of stacked materials Beiuoshy good electrical insulators the movement of stock unless earthed will allow the build up of stati All stock shapes are chemically stable at normal temperature Whil t some raw materials used in their manufacture may themselves pre ent a toxic hazard once incorporated into the lOck bape they no long r constitute such a hazard and no dermatitic bazard are known nor are any
unfiJied ductwork and minimise double handling It is important to recognise that ductwork panels joint and corners arc susceptible to damage and care must be taken wheu band ling such material through a site During handling individual item of duct work may be liable to light cross sectional deformation until thev become an integral pan of a completed ductwork system Whilst this may temporarily detract from its intended appearance thi deformation will not have any detrimental effect on the functionality of the finally a semblecl system Installation of duct work and asociated plant items ill illevitably involve manual handUng The responsibi Iiry of employers and employees to a ses the risk of personal injury during mallual handling operations is et out in the HS E publication L23 Guidance on Manual Handling Regulations 1992
environmental problems expected 84 Site storage
B2 fransport Large capacity vehicles with high-sided open or closed-top bodies are tlle mo t suitable for the transport of dllctwork Careful consideration should be given to the
Adequate floor space IDust be provided within tbe building for the site storage of ductvork Such storage shalt make due allowance for thc stOf(ne of ductwork in stacks such that access ~ egt
between them is of sufficient width to pennil the removal of item without interference to
unloading of transport on sit a not all siJes b n fit from the material handlino- and access facilities that exi [ in a manufacturing workshop such as crane- fork-lifts or loading bay Site handJiog facilities along with
adjoining sta ks Ductvork components should be positioned so a to avoid crushing Ductwork of small panel size may be stored horizontally however care should be exercised to ensure that tack sizes are limited 10 within
ehicular acce s restrictions may itilluence the type and ize of transport to be uWised
engtlls of ductwork should be positioned 0
the tmctural strength of the duct sections to prevent distortion of the lower sections within the stack
as to avoid crushing Lengths Witll projections such as branches and bends i1anges girths damper quadrauL should be loaded so as to
54
DW154 S1tciic(ltioll for Plastics Ductwork
85 Internal cleanliness of new ductwork The site storage of ductwork introduces the important cODsideration of maintaining the internal cleanliness of the ductwork R feren e should be made to HVCA documentshybull DWffM2 Guide to Good Practice - internal
Cleanliness of New Ductwork Installations If the above conditioDs can not be satisfied consideration should be given by tJle designer to amending the specification to include for Po t Installation Cleaning as covered by tJ1C HVCA documentshybull TRJ17 Guide to Good Practic - Cleanliness
of Ventilation Systems
APPE DIXC
Fi e Retardant inishes C1 Improvement in the fire retardancy of plastic
ducts can be achieved to varying degrees and is wholly dependent llPOll the surface coating laminating resin selected and construction specification adopted In some instances smoke emission is coILSidered equaUy with other speci fication requirernen ts of the materials resistance to ignition and bumjng It is therefore important for design rs to establ ish the clients and officers detailed requirements and not rely on a tbird party interpretation of fire resisting or fire retardant Where possible the specification should refer dir etly to compliance with a British or European Standard identifying the specific sections applicable There are various types of resin and mat rcLnforcements that can achieve a Class 1 surface spread of flame ratin o when tested according to BS476 Part 7 (1987) This test puts materials illto Class I - 4 in descending order of perfoDllance according to the rat and extent of flame spread over their surfac under standard beating conditions Materials should also be tested for flre propagarion to BS476 Part 6 (1989) Tbi tesr measures the amount and rate of heat evolved by the material when subjected to standard heating
conditions Test results are given as an index of Perfonnance (i) whicb is based on three sub indices (iJ (i1) (h) The higher the value of the Index of Performance (i) the greater is the material s contribution to fire growth The higher the value of the sub-index 0) rhe greater the ease of ignition aod flame spread The highest product performance classification as defined in Approved Document B of the Building Regulations is Class O This is acLlieved if a material surface of a composite ploduct i~ either a) composed throughout of materials of
limited combustibility or b) a Class I material which has a tlre
propagation index (i) of not more than 12 and sub-index (i l ) of nor more than 6
01 J Class 0 is not a cla$sif1cation identified in any British Standard test
There are resin system reported to be classified to Class O when tested to BS476 Pcl1S 6 and 7 however designers need to ensure that such sysrems can be applied to their proposed design In propriety resinmat system available the fabrication techniques and COITect application are critical to the integrity of the reinforcing and clas ificatiol1 For example in some systems the u e of a non-fire retardant gelcont on a fire retardant substrate would reduce the classification For further information see HVCA publication DW144 Appendix D
55
DW154 SplCijiClIliol1 for Plastics Ductwork
x Guidance otes For nspectmiddoton Servicing a d
Clean-ng Access Openings
D1 GE ERAL This appendix highlight in ummary fOI111
the acce considerations that hould be made by the design r iD terms of inspection servicing and cleaning Having considered the seop and the design of the dUCI work system relative to the guidelines outlined below the designer should clearly indicate which levels of acces should be incorporated into the manufacture of a new duct work system (See Table 14 and Note I b low it
D2 DESIGN CONSIDERATIONS
D21 In ptction and servicing requireshyments are set out in Section 15 of Lhis specification
D22 Cleaning requirements are set out in the HVCA pubUcation TRl7 Guide to Good Practice Clean Lines of Ventilation Systems and the guide tates The precise location ize and
type of access would be dependent on the type of ductwork cleaning inspection and te ting metbods to b adopted Care protection and standards of cleanliness prior LO cOlllmisionin o
are set out in th AV A publication DWITM2 Guide to Good Practice Internal Cleanliness of New Ductwork Installations and th guide state Wh re specific limits of cleanliness are required ductwork sball be cleaned after installation by a spcialist cleaning contractor It will b in the interests of tht desioner botb financially and practically to cunsider employing a specialist c1eauing contractor at tbe
outset of a contract to internally clean newly installed ductwork prior to bandover This approach would reali e the following benefit shyi) Tb actual numb r of cleaning
access panels could be detennined to suit the method of cleaning to be adopted (This may be 1 s than the maximum requiremen listed under Lev 13 of Table 14)
ii) Clear directions could b given to the ductwork contractor as to tJle size and location of cleaning access panels that are required to be fitted during the mauushyfaclunng pro s
iii) The specialist cleaning operation prior to commi ioning vould enable the cleaning contractor to verify the practical acee requirement for the future cleaning operation associated -vitb a regular maintenance programme
iv) A specialist cleaning operation prior to commissioning would allow the designer to omit from the speeilicatiolJ the DWrrM2 requirem nt for factory sealing protection wipe downs and capping-off
v) Specialist Ieall ill 0 to the measurable standard defin d in TR17 will allow an objective definition of cleanline to be achieved
Car ful consideration must be gIven by the designer to the practl aJ problems associated witb the manufacture and fitting of suitably si Led access panel on small cross section duct and on the circular faces of rouod and flat oval ducts in particular
D23 Special con ideration must be given by the de igner to the practical problems associated with gaining personnel access to heavily congested ceiling areas and multi-la red du twork systems This approach would avoid
56
DW154 Spfciication for Plastics Ductwork
the possibility of access panels being D3 ACCESS 0 IN-LINE EQUIPMENT incorporated into a ductwork system at the This appendix unly covers acc il1spection manufacturing stage that were later found in through the ductwork body adjacent to an item practice to be inaccessible for either ervicing of in-line equipment and not openings in the or cleaning activities equipment itself
able 14 Acce requirements for inspection servicing and cleaning
HVCA PUBLICATIO REFE NeE (uidtgt 10 Gund Prartict
Adjace t OW144 Cleanliness orVcnlillltio S~lcr~ fRjJ7
in-line LeyeJ 1 Level 2 Level 3 ite sequipment pcdionSen lcin~ Section d C1eaniJl( SUn(O)lnspc lion Palle ltk~m_n
2011 (minimum OiL Jubje-ct to duct ~zel (ft~ -Panels
Control Da pcrs One (inspection) 203 One 300 mm x 200 mm Both sid Fire Dampers One (sCTjdJl~) 20211 One 300 0101 x 200 mm One side HeatingCooling Coils One (inspedion) 20213 One 300 mm x 200 mm (lIpstream) Both sides Attenuators (rectangular) None required One 300 mm x 200 mm (downstream) Both sides Attenuators (circular) one retluired One 300 mm x 200 mm (downstream) One side Filter Sections One (inspection) 20212 one required Uoth sides Air Turn Vanes None requjred None required Both sides Changes of Direction None required one required One side In-Duct FansDevices One (inspection) 20213 None required Both sides l
1 In the absence of any indication by the designer only Level ) access will be jncorporated into a new ductwork system
2 Tbe panel izes associated with Lev lis I and 3 acee s ar e middottablished by reference to Section 20 of DW144 and Section 2 ofTRll7 respectively
57
DW154 Speclfifatio for Plastics Ductwork
pA XE
B-bliography Included in this Bibliography are technical pUblications which may be of interest (0 ductwork designers fabricators and erectors and to tho e in the heating ventilatlng air conditioning industries generally nquiric should be made of the relevant organisation at the address quoted Since its publication other addresse contained within 0V154 mav have changed and some pubJicalions may have been superseded
HEATING AND VENTILATING CONTRACTORS ASSOCIATION
4 Palace Court London W2 4JG Telephone 020-7229 2488 Fax 020-7727 9268
Orders fo FlY A Publications Old Matlsion House Eamont Bridge Penrith Cumbria CA 10 2BX (Telephone 01768 864771 Fax 01768 86718) Email hvcapoblicationshvwelfarecouk DWn 44 pe ilicatiun for sheet mctal duclwork (Iow- mediulllshy
and high-pressure) 1998) DWIl4 A practical guide to dUGI ork I akage te ting
(revised 2000) DWII54 Specification for plastic~ duct rk DW171 Guide to good Practice for kitchen venlibtion system DW191 Guide to good pracuce glass fibre ductwoJk DwrrMI Acceptance cheme for new products - Redangolar cro
joint classification Guide to good pra tice - Internal cleanliness of new ductwork installations Guide to good practice for the design for the Installation of lire and smoke uampers
J 1Other puhlications
HampV safely guide 5th edition JS2 Tool box talks JS5 Weldlng Safety booklet JSI9 afety facts bo klet Fact sheets 1-24 2nd edition JS2J COSHH manual volume 1 Advice on compliance with the
regulations 1521A CO I-rH manual volume 2 Asses mcnt h ets JS23 Ri k management manual TR3 BrazinltT and bronze welding of copper pipework cUld sheet
(I 976) TR5 Welding of carbon steel pipework (1980)
TR6 Guide to Good Practice for Site Pre sure Testing of Pipework (19 0) Guide to good practice cleanliness of ventilation Ylem
CHARTERED IN TITUTlO OF BUILDING SERVICES E G EERS Delta House 222 Balham High Road London SW12 9BS rTelephone 020-8675 5211 Fax 020-8675 5449) CIBSE Guide Volume A Design Data Volume B In tallatiol1 and quipment Data Volume C Reference Data
CommlssioniJIg Codes These Codes eover the preliminary checkS eUing to work and regulation of vanous catcgories 0 plan The Codes give a guide to design implications Series A Air Distnbution Systems Series B Boiler Plant
ri s C Automatic Conlrol ystems Cr1es R Refrigerating Sy terns
Sene iN Water Distribution Systems
Technkal Memonllda TM 4 Design Notes for the Middle East TM bull Design otes for Ductwork TM 13 Minimi iog lhc Risk of egiounaires Disease
Research Reports RROI95 Ventilation system hygiene - A review of published
infomlatioo on lhe occurrence and ffects of Olltamination Rl~02J95 Air-to-air heal rec v ry RR0395 rnfluen e of HV C on smoke detectors
ATlONAL ENI [ERING SPECIFICATION LfMITED Southgatc hamber 3739 Southgate Street Winchester S023 9EH (Telephone 01962 842058 Fax 01962 R(8982) BUfLDING S RVICES RESEARCH AND [ ORMATION ASSOCIATIO Old Bracknell Lane West Bracknell Berkshire RG 12 4AH (Telephone Brackl1eU (01344) 426511 Fax 01344 487 -7 )
Application Guides AGln4 De tglJing Vana~le Volume middotylans for KOOnl
iir Movement AG1I91 Commissioning of V Sylcms in Buildings 11 6194 Fire Dampers
B) 94 cntiJalion or KitcneTls
AG389 The Commls ionin of Air Systems In Buildmgs AH2192 Commissioning of Bern - A ~ode of Practice TN2417 I Fire Dampec il) Ventilating Ducl
BEATING VENTILATING A AIR CONDITION G MA UFACTURERS ASSOCIATIO (HEVAC) HEVAC Henley Road Medmenham Marlow Buck SU 2ER (Telephone 01491 578674 ox 01491 575024 Emoimiddot infofetacouk)
Publicatjons Air Diffusion Guide Guide to Air Handling Unit Leakage Testing Guide to Good Practice Air Handling Unit Real Room Acoustic ~ st Procedure Specification for the ertiiicatioll ofAir Filters Method of Test for Water Rejection PerfOnTlatce of Louvrcs Subjected 1(1
Simulated Rainfall Test Procedure for Acoustic Loo cs Specification 10 Floor GrilJes - Types Performan e and Method ofTest Specification for the Determination of the Collection Efficiency of SilJ1d
Trap Louvre Domestic Mechwlical Vclltllalion Systems with Heal Recovery Fan Application Guid
~an and Ouctwork Installation Guide Guide to Fan Noise and Vibration
pecification of Requirements for JallJral Smoke and Heal Exhausl Ventilators
pecification for Powered Smoke and Heat Exhaust Ventilators
Specification of Requirements for Smoke Curtains Design Gujue of Smoke Ventilation for Single Storey Lodustrilll Building~
Including those with Mezzanine Floor and IIi Racked Storage Warehou es - Issue 3
Guidance for the Design of Smoke entilation YSlem for Covered and Undergrollnd Car Parks - lssue 1
Application of SOloke Control Equipment and Syst m Guid to Good Practice - Isue J
58
DW154 Sp(C~tiifitiol for Plastics Ductwork
BRITISH STANDARDS INSTIT TION Sales Department 101 P ntooviLle Road London NI 9ND (felephone 020-78 1 78801)
CP 413 1973 Ducts for building ervices
SS 476 Fire tes on building matenals and lruc(ure
Part 4 19 4 Non-combustibility lest or materials
Part 6 I Fire propagation lest for materials
Part 7 1993 Surface spread of tlarnJ tesls for materia
Part 20 1987 Fir resistance of elements of construction
Part 21 1987 Fire r sistlUlce of loadbeanng elements of construction
Part 22 1987 Fhe istallceofllon-loadbearing elemcllts ofconsttuclion Part 23 1987 Contribution of componcnts to the fire resistance 0 a
structure
Part 24t987 Fire resi lance of wl1lilation ductl
SS 5588 nan 919 0 Fire Precautions III thc desIgn and OOSlnJ lion of buildings
S 729 1971 Hot dip galvanized oatiugs (or irOIl aod stcel articles
BS 1449 Steel plate sheet and Irip
Pan 11991 Carbon steel plate heel and strip Part 2 1983 Stainless steel plate sheer and strip
and
B middotENJOI49-2 996 BSEN 10149- 1991)
BSEN 10131 1992
BSEN22063 Sprayed metal coarings 1994 Protection of iron and steel by aluminium and zinc against
atmospheric cOlosion Irotectiotl of iron and ste I against corro ion and oxishydation at elevared temperatures
BS 353 1981 Glossary of lerms relnting to thermal insulation
BS ISO 1479 Self-tapplngscrewsandmetallicdri c crew
B -lSO 7049
1994
B 4800 1989 Painl colour for building purposes B 4848 l0 rolled structural steel sections
Part4 1972 Equal and unequal angles BS 5422 1990 Specification for the use of therm illuating matcriulS
SS 5720 1979 ode of practice for mechanical veutilating and air C 11shy
dirionin bull in building
l3S PR 12814-1 Bend resting for plasric welds
SS PR 12814-2 Tensile testing for plastic welds
SS PR 13067 Appro altesting for plastic welds
BS PR EN I 100-] Vi ual in pection ofplaslic welds
SHEET METAL AND AIR CONDITIONING CONTR-CTORS NATIONAL ASSOCIATION INC (SMACNA) Headquarters 420 I Lafayeue Center Drive Chanlilly Virginia 2051-1209
Mailing Address pa Box 221230 Cbantilly Virginilt120 153-1230
Telephone (703) 803-2980 Fax (703) 803-3732
Accepted IJJdustry Pl3Gtice for Industrial Duct Constnlelion 197 ) i-rchitecmral Sheet kwl Manual ([993)
Comractors Guide lor Modification 10 ooslruerion Colllraets 1993 Ducted Eleclric Heat Guide for ir Handling Ssrerns (1994)
En~rgy ollservatioD Guidelines (1984) Energy Recovery Equipment yslClllS (199l
Fibrou GIns Duct onS1ntClion Standards (1992)
Fire Smoke amp Radiation Damper In tall Guide for HVA Syst ms (1992) Guide t leel Stack 1(95)
HVA Air Duct Leakage Test Manual (19 ) HVA COlllmissioning lvlanual (1994)
H A Duct Construction Standards-Metal amp Flexible (1995) Addendum 01 (Nov 1997)
HVA Duct Systems Inspection Guide (1989)
HVA ySlems-Application (1986) nVAC ByternS-DLlct D ign (1990)
HVi Systems-Testing Adjusting amp Balancing (1993)
indoor Air Quality Manual (1993) tcheu quipment Fabrication Guidelmes (1990)
Managers Guide for elding (1993)
Rectangular Industrial Duct Cons1TUction Standards (19 0) Round Industrial Duct oustmction Standards (1977)
Sei mic Restraint Manual (1991) (wl Appendix E 1993) SMACNA Ma le Index ()fTechnical Publications (1995) Tbennoplnstic Duct CPY ) Construction Manual 1994)
DEPARTME OF THE ENVIRO MENT (Publications Centre) H Stationery Oflice 5 Nine Elms Lane London SWS 5DR
MampEJ 011972 Electrical in tallat1011 in buildings ( ew Editiou)
IampE 0319 Healing hot and cold wat r steam and gas losla1lations for buildings
M amp - No4 1970 Central heating and hot and cold ~ ateT in tallations for
dwelling
M amp ENo100 1971 Mechanical ventilation for building~
ASSOCIATION FOR SPECIALIST FIRE PROTECTlO As ociation House 235 Ash Road AJdershot Hampshire GUl2 4DD
Telephone OJ25221322 Fax 0 J252 333901
lublicalioos Fire Ratcd and moke Outlet Ducrwork An Industry Guide t Design and InSlalla lioll
HEALTH AND SAFETY EXEC TIVE Rose Court 2 Southwark Bridge London SEl 9HS Telephone 020-7717 6000
TWJ THE WELD G TlTUTE Abington Hall Abington Cambridge CB16AL Telepbone 0 J223 89162
Publication DatJ Oil w~ldll1g of lhermopla lics
59
DW154 wciiwlioll for Plastics Ductwork
A -=--DIX
Factors
Specific gravity shy pp = 091 approx UPVC = 14 approx
Some miscellaneous conversion factors
To convert
Length Inches to millimetres Feet to metres
Multiply by
2540 03048
To convert
Millimetres to inches Metres to feet
vIultiply by
003937 3281
Area Square inches to square millimetres 6452 Square millimetres to square inches 000155 Square feet to square metres 00929 Square metres to square feet 10764
Volume Cubic feet to cubic metres Cubic feet to litres Gallons (UK) to litres
002832 2831 4546
Cubic metres to cubic feet Litres to cubic feet Litres to gallons (UK)
35315 00353
022
Mass Ounces to grams Pounds to kiJograms Tons to tonnes
2835 04536
1016
Grams to ounces Kilograms to pounds Tonnes to tons
003527 2205
09842
Volume flow Cubic feet per minute to cubic Cubic metres per second to cubic
metres per second 0000472 feet per minute 2119 Cubic feet per mIDute to litres Litres per second to cubic feet
per second 04719 per minute 2119
Motion Feet per minute to metres per second 000508 Metres per second to feet per minute 197
Pressure Inches water gauge to millibars 2491 Inches wateJ- gauge to pascals (Pa) 2491 I Pa = I ewton per square metre = 10-2 millibars
60
Heating and Ventilating Contractors Association Esca House 34 Palace Court London W2 4JG
Tel 020 7313 4900
e-mail contact Itvcaorguk web site wwwhvcaorguk
Fax 020 7727 9268
DW154 Specificotiol for Plastics Ductwork
182 LOClt1tion Flexible joint are typicltllly lIsed at building expansion joint and fan inletsoutlets Any others required should be indicated on the de ign drawings Care should be taken to maintain alignment across jointsconnections
183 Length Flexible Jomts shall be kept as short as pra middottieable above a minimum eft ctive length of SO mm In no ca e shall a flexible joint exceed 250 mm in lengtb
184 Connections to rectang a ducts With flanged rectangular connections Ule tlexible material shall be held in pLace with flat pIa tic strip of not less U1an 6 mm thick ltlttached to the flanges using uitabJe fixings The more heavy weight type of fleAible mateLial may also be obtained formed into a channel ection with corners fitted to give a neat air tight j int For pigot connections the Be ible material shall b held in place with flat pIa tic trips n t less than 6 mm thick
t 85 Connections to circular ducts With tlanged circular connections the flexibl material shall be held in place with flat plastic backing strips or proprietary clip bands with screw or toggle fast ners
186 Welded flexible connections (Rectangular and Circular) Where the parent and llexibl material are from imilar ba ed products they can be joined to the duct u ing the welding method described in Section 823
19 PROTECT VE FINISHES
191 nles otherwise stated all ductwork shall be mallllfactured in mat fial as pecified in tbis specification Any special coatingpaint fmishes to be provid d by the duct work contractor sball be advisd by th de igner
20 CONNECTIONS TO BUILDING OPENINGS
201 Fanning and finishing building op nings are not the repoJlsibjlity of the duftw( rk contractor and the note that follow are for guidance purpo e only
2011 Openings in brick block or concrete walls shall have inset frames to provide a suitable means of fixing grille louver masking flanges or the tlanged ends of ductwork The illset frames shall be conslnlcted to maintain the structural int grity of the wlll and where applicable cavities shall be suitably lined
2012 Openin s in dry linino partItIons shall have inset frames a 2011
2013 Openjngs in cladding walls and roofs shall have flaoged leevesframes to provide a suitable means of fixing a 2011
2014 Horizontal and vertical opening xposed to oLltside atmo phere hall
be provided with a suitable weathering fini h at the external face especially where profiled cladding is used
2015 Timber framed op nings are not permitted In fj re compart ment barriers
202 Ductwork connections to building openings hall have a flange of suitable profile to permit practical fixing to the openillg frame In selecting the profile consideration shall be given to Tabl~s 2 and 10 in this specitication relating to duct ize and rating Gasket strip or sealant shall be ltlpplied between the tJaoge and building op ning frame
21 DISCHARGEEXHAUST TERMINAL
21 Tbese shall be vertical open ended and designed to meet and comply with current r gularions on contaminated flue The designer hall ensure that the de ign and perf rmance i suitable for its intended purpose Examples of some typical terminal designs are SbOiD in Figbull 102 10 bull 104 amp 105
27
DW154 SpedjimioTl for Plastics Ductwork
22 THERMAL INSULATION
221 The provision and application of thermal insulation to ductwork is not the responsibility of the ductwork contractor
222 Where ductwork is required to be preshyinsulated the specification should be agreed with tbe designer
223 Where the temperature of the air within the duct promotes condensation on the exterior surface of the duct and cause moisture penetration througb the thermal insulation vapour scaling may be required and in this case the most important requirement is to limit penetration of the seal
The extent of any vapour sealing of ductwork thermal insulation and the support method to be u ed must be clearly pecitled in advance by the designer
224 For detailed information on the thermal insulation of ductwork reference should be made to BS 5422 1990 which covers the specification for thermal insulation materials on pipes ductwork and equipment (in the temperature range -40degC to +700degC) and BS 5970 1992 which is a Code of Practic for Thermal Insulation of Pipework and Equipment (in the temperature range -lOOdegC to +870degC)
23 FIRE RETARDANT FINISHES ON PLAST C DUCTWORK
231 The designer should note tbat ductwork constructed to DW154 has no teted fire rating or information see Appendix C
24 REINFORCEMENT OF DUCTS WITH GRP LAMINATE
241 General Where ductwork is required in larg T izes than are covered by Tables 2 4 6 amp 7 or with the increased strength sometimes necessary for industrial use external reinforcement is normally pwvided by applicatioD of glass fibreresin laminate
GRP systems will bond satisfactorily with standard UPVC sheet but for pp it is
nece sary to use a specially prepared sheet with a glass fabric backing incorporated dOling manufactllfe
The detailed techniques of fabrication using GRP are outside the scope of this speci lcation but the following notes are offered for guidance of ductwork fabricators
242 Materials
2421 Quality The laminate is made up of polyester resin complying with BS 3532 and glass fibre complying with BS 3496 or BS 3749 The nominal ratio of resin to glass fibre should be 7030 by weight
2422 Minimum properties The laminate shall comply with the followiog mini mum pbysical properties
Tensile strength - 70 MNm Tensile modulus - 7 Gl m Flexural strength - 140 M Im Bond strength (hetween laminate and substrate Not less than 7MNm Bmcol hardnes Not le s than manufacturers specification
The GRP reinforcement educe the expansion of the parent material but the resultant stre ses arc well within rhe strength of the bond However the Iinear thermal expansion curve shown in Figs 34 amp 35 will serve as a guide
Surface resistivity electrkal propcltles and acoustical propertie are similar to the relevanl unreinforced materials The fire retarding properties of GRP may be improved by the use of specialisl laminating resin
2423 Forms available GRP Laminate should be built up from the separate materials ie resin aod glass fibre in the form of chopped
I strand mat or spray ravings
28
DW154 Spcification for Plastics Ductwork
2424 Workshop conditions Polyester resuls are sensItIve to lmperature and the workshop hould b maintained at a temperature of herween 20deg and 25degC HiOh relative humidities and damp onditions should be avoided A good rate of air change must be pro icled pJeferably by m chanical ventilation
2425 Storage of materials Resin and urin o agents shouJd be stored in dark cool condirions away from the working area and in confonnit with statutor requireshyments for tJle middottorage of flarmnable liquid Because of Ule Limited torage lif of the unmixed resin and curing a eot mal lials ~hould be ch eked before use to enLlfe that they are within the manufacturer pe ified sh If life (usually ix month from the dm of manufacrure)
Glass fi re should be stored separately und r clean dry conditions
243 Surface preparafon
2431 UPVC To achieve the specified bond strengtll the urface to which the GRP is applied mut first be thoroughly cleaned and then etched either by mechanical means or by the use of a suitable solvent
2432 pp with glass fabric backing To achieve the specified bond middottrength the fabric backing must be thoroughly impregnated Witll resin
244 Mixing the materials for use The re in 1 a three part mix compri lng base I sin hardener and accelerator The manufactur rs pecj[ied proportions are critical and th llUxmg sequenc pecified must be meticulously foUowed
The resin has a very limited life after mixing and before u e It is dependent on the characteri tics and bulk of th resin the alllount of hardener the degree and method of acceleration and the workshop onditions
245 Methods of application
2451 General The mixed resin may be applied by hand or b pray c1epoition The operation must b completed within the gel time of th y tern and tbe laminat fully cOI1olidated to achi v the phy ieal properties pecified
2452 Hand lay-up The duct surface i coated by hand with resin Llsing a brush and a mar of gla fibp orked in until full consolidation achieved Th proc is repeated untiJ th requird thicknes i obtained
2453 Spray depo Won The duct surface is coated WiUl re in by spray gun with the chopped glass roving added through a separate nozzle The full thickne i obtain d in layer with con olidation of each layer by hand roller
246 Construction
2461 General M ini mum COllst ructional requireshyments are pe itied ill Tabl 10 for rectangular and Table 1J for circular dUClS
2462 Joints and stiffeners Fig 29 30 31 32 amp 33 hoI TOSS
joint and tiffener for reinforced UPVC and PBPP duct
247 Worki g practices The fabrication of ductwork pecifiecl ill thi document i not affected by the addition of GRP
29
DW154 SfJcdJicatiOt for Plastics Ductwork
Table 10 Minimum constructional requirements shy
Longer Side Minimum Sheet Thicknes and
GRP Reinforcement
UPVC FBIPP 1 2 3
mm mm mm Up to 1000 3 plus 3 plus
06 kgm2 06 kgOIl GRP GRP
1001 to 2250 45 plus 3 plus 06 kgm 12 kgm
GRP GRP
2251 to 3000 45 plus 6 plus 12 kgm 12 kgm
GRP GRP
Cross Joints
UPVCFBPP 4
mm socket amp spigot
as Fig 30 or flanged as Fig 29
75 x 9 flange welded on both sides as Fig 29
75 x 9 tlange welded on both sides as Fig 29
rectangular GRP reinforced ducts
SlifTeners Maximum Spacing Between
JointsSljffeners UPVCIFBIPP UPVCFBPP
5 6 mm mm
75 x 9 flat 800 as Fig 31 or
50 x 50 x 5 plastic or MS inverted angle as Fig 32
or tormer as Fig 33
75 x 9 flat 600 as Fig 31 or
50 x 50 x 5 plastic or MS inverted angle as Fig 32
or former as Fig 33
75 x 9 flat 600+shyas Fig 31 or 50 x 50 x 5 plastic
or MS inverted angle as Fig 32
or former as Fig 33
Note 1 On rectangular duct up to 400 mm longer side no stiffeners are required 2 Applies to Tables 10 amp I I For COlJstructional operating temperature limits refer to Part 2 clause 5A 3 Tables 10 amp II apply to all pres ure classes up lo ]500 Pa
Table 11
Diameter
1 III
lJp to 1000
1001 to 1750
1751 to 2500
Minimum Sheet Thickness and
GRP Reinforcement
UPVC FBPP 2 3
mm mm 3 plus 3 plus
06 kgm 06 kgm GRP GRP
45 plus 3 plus 06 kgm2 18 kgm
GRP GRP
6 plus 6 plus 12 kglm2 18 kgm1
GRP GRP
Cross Joints
UPVCFBPP 4 III
socket amp spigot as Fig 30 or flaoged as Fig 29
75 x 9 flange welded on both sides as Fig 29
75 x 9 flange welded 00
both sides as Fi 29
inforced ducts
Maximum Spacing Between
JointsStiffeners UPVCIFBPP
6 mm 2400
800
600
Stiffencrs
UPVCFBPP 5
mm 50 x 9 flat as Fig 31
75 x 9 flat as Fig 31 or former as Fig 33 75 x 9 tlat as Fig 31 or t()rmer as Fi 33
ote On extruded tube tip to 600mm diameter no stiffenergt are required
30
DW154 Specificatioll for Plastics Ductwork
G - Cross joints and tiffeners
Fig 29 Flange Joint Fig32 Stiffener shy inverted angle
M artiPfCuQkbdd erttpObri) Wl111 RP tlddtlt
_- GRPloliu] lh~
Fig 30 Socket and spigot joint Fig33 Stiffener shy use of former
Fig 31 Stiffener Flat
I Pv FlPP ~ ~lmJaDUA1) d
OMrlQ rrnall 1( tQlS
25 STANDARD COMPONENT DRAWINGS AND ABBREVIATIONS
251 The illustrations in this section not only highlight where applicable geometric limjtations for the de ign and manufacture or ductwork components but also recommend
standard drawing representation terminology and abbreviations for both duetwork components and some of the more commonly used ancillaryplant items
252 Designers and surveyors should note that bills of quantities should provide a full description
3)
---
v
DW154 Spcc(fim(ml for Plastics Ductwork
Fig 34 Linear Thermal Expansion
u c 0 N ro 0)
b 0)
S
sect0
5 oS cl) 0)
~
on ~ ltl
c U
-30 -20 -10 0 10 20 30 40 50 60 70 80 90 TEMPRATURE C
~ V
-
~~c_ ~
~V
V ~
-7 ~
-- ~V ----
v
-6
+14
+12
+10
+8
+6
+4
+2
0
-2
--4
ig 35 Typical Design Stress tor UPVC and P
7
6
r shy 5E
-c E----0 4t) VJ 0)
ci5 0Jl 3
~
0)
Cl
2
1
o
UPVC
1
000
1
1
pp
- r-- shy r----- shy - t--shy I
__0
-30 -20 -10 0 10 20 30 40 50 60 70 80 90 TEMPERATURE C C
Note Figso 14 amp 35 shaded area refers to GRP reinforced duct
32
DW154 Speciicfltirm for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - REC ~NGULAR
Splilt~r Posilion W-mm pliucr
A B c 40]--QOO 1 W - -
601-1000 1 W4 Wf2 -
1001-1800 3 WI W3 W2
FIG DRAWING DETAfiS
tU]36 ATI Straight Duct with socket and spigol joint
rn [037 Straight Duct with flanged joints
[I []38 Straight Duct with flanged joints
rkJ Short Radius Bend
39 Applies to any augl and for duct up to 400 n11n wide
Minimum (I1m31 radills = 100 mm
Medium Radius Bend (a illustrated)
[kJ Applies to any angle
40 Long Radiu Bend Similar but radius = W
Throlll radius = W2 Applies to any angle
- Short Radius Bend with plitlers
I -shy -shy u co - t lt Li--_ 41 t 0 ~ I I I
~ I
L 1W
Minimum waal radius = 100 mm Splitters not required in bend angle less than 45deg
42 QJ1 Square Bend with turning vanes ij
3
DW154 SP(L~ficatioll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - RECTANGULAR
FIG DRAWl G DETADS
43
~
I v
L L Radius Tee with internal deflectors
44
~ Radiussed Twin Bend
45
Imiddot
er Swept Branch
46 U-
Sqoare Tee with Turning Vanes
47
~ f
Breeches Piece
48 0 y l Piece
34
DW154 Specificatioll for Plastics Ductwork
STANDARD COMPONENT RAWINGS - ECTANGULAR
55
54
51
50
53
52
49
FIG
~MX
RAWlNG
DmiddotMAX
EfjMAX
Minimum throat rndius = 100 mm
Rectangular shy Round Transformatioll
Eccentric Taper 225deg max in either plane Spliller are required for angles greater than 225deg and hould bi eet the angle between any side and duct centreline
DETATLS
Angled Offset
OUset Taper Splitters are required for angle greater than 22 0
and shoold bi eet the angl between any side and dUCI centrelinc
Mitred Offset
Concentrk Taper 2250 max in ither plane SpUtters are required for angle greater than 225deg and should bisect the angle between any side and duel c ntreline
Radiussed Offset
35
DW154 Splcilcuthm for Plastics Ductwork
STANDARD COMPONENT DRAWINGS ~ RECTANGU AR
Branch ducl DimCllsions widlh (W) (A)
urnl mm up lO 200 75
300 100 400 125 600 150
Ocr 600 200
FIG DRAWlNG DETAILS
56 poundplusmni~~ Rectan~lar - Flat Oval Transformation
57 [ Square Branch
58 er Angled Branch
Branch dUCI Dimensions wfdth (W) (A)
[- mm mm59 3shy Shoe Branch Up (0 200 75
--shy AIshy + 300 100
400 125
450 MAX 600 150
Over 600 200
Branch duct DimensIOn
rP X width (W) A)
60 - 1--shy _
~ mm mm
Bell Mouth Branch pto 200 75 300 100 t 400 125
600 150 Over 600 200
0=0 61 -
~ Bell Mouth
- shy T 4-5deg M x
--I 1-shy
TJ
62 X I ] I
Tele-scopic Joint I Illustrated with flangeL
X63
SBD Single Bladed Damper
36
---
DW154 Spedicatioll for Plastics Ductwork
STANDARD OMPONENT DRAWINGS - RECTANGULAR
DRAWING DETAILSFIG
64 on-Return DamperNRD shyshy
shyXbull
Multi-Leaf Damper Can be piggoted or flanged oppo cd or parallel blade
Alternative controls areshy
q p [gtshy
J HD65 Hand
~MD otori ed
PO Pneumalic
L-lt
l 13G 66 Blast Gate DamperX X
FireSmoke DampersSleeves
211r Ratinggtshy----
L_-
---
----
r----
Ir-- shy
IL- _-l
2hr
With i tallation frame
67 41 r Rating
4hr
Smoke damper SD
Intumc cent Sleeve L-d
37
DW154 Specijicutiolt for Plastics Ductwork
FIG
68
69
70
71
STANDARD COMPONET DRAWINGS shy REC ANGULAR
DRAVING DETAILS
gtshy Access Openings
AP 6 Access Panel - Rerno able
w [ ~ Access Door - Hinged
I ~le Inspection Cover
le -I reg -lt
~X X Flexible Connection
~ Drop Cheeked Radiussed Twin Bend
U Drop Cheek Bend
I
72 Air Flow SymbolX
38
DW154 Specifim[ioll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - ECTANGULAR
FIG DRAWING DETAILS
73
74
75
76
77
Q
Q
rp---t
~
V- I Ir---I
JL --11
THE ABOVE DETAILS TYPICAL PLENUM
Air Terminal Plenums
Plenum with side connection
Plenum with top connection
Cover plate with connection
Special plenum with connection
elescopic conn ction in direction of air flow
39
DW154 SpecijicotiOll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG
78
79
80
81
DRAWING
-23~---pound3-(MALE) (FEMAJE)
-t=j--_j(--d-shy
--L
~ THROAT RADI S= D AS T NDARD
e ~
THROAT Rjf)lU = D A MU)
DETAILS
Straight Duct With male and female connectors
Straight Duct With flange joint and slip joint
Bend MouldedIFormed Applies to any angle ego 30deg45deg60deg90deg Medium radius bend as illustrated Long radius similar but throat radius 0
Segmented Bend 90deg four section minjmum as illustrated
Other Angles 60deg = 3 sections 45deg = 3 sections 30deg = 2 sections
I
i
40 shy
DW154 Speciicafinll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG DRAWING DETAlLS
82 Segmented Twin Bend Radius = D2 max
May also be fabricated from tube
83 Equal Tee MouldedIFormed
84 -~ 1in Bend MouldedIFormed
85 Taper Concentric 1 0 as iUu trated Eccentric 30deg iJJcLuded angle
86 Short Taper
41
DW154 SpcUicatol1 for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG DRAWING DETAILS
87 30 max Offset
Angle Branch
Bran h dUCI Dimcnsions dia (D) lA)
Shoe Branch mm mm 88 Cl
Off rectanguJur Up 10 200 75 lOO 10 400 125
- 00 150 Over 600 200
Bl1IllCh duct DimenlOns din (D) (A
~-$a-Conical Branch mm mm
89 Also acceptable with Up 10 200 r
full conical surface 300 10
400 125
END VrE -shy 600 150 Over 600 200
90
m 75
100 12 150 200
mm Up to 200
_ 300 400
600 Over 600
iUtred Branch
Shoe Branch
J-L----U ~ Bell oulh Branch
ENDV1EW
93
92
91
42
DW154 Specificatiol for Plastics Ductwork
STANDARD OMPONENT DRAWINGS - CIRCULAR
FIG
94
DRAW G
I
~ 30deg 090deg
Breeches Piece
DETAILS
95 amp-----~ Blank End
~-----p Multi-Leaf Damper Can be piggolcd or fianged opposed or parallel blade
Alternative controls areshyri=-+- L-T~
I
---
LT~
I r- -
-+1
J HO Hand96
bMD Molori cd
PD Pneumatic
tl-shy bull
Single Bladed Damper 97 ~ saD
on-Return Damper Vertical application only 98 m~D
43
DW154 Sf1tcificatioll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG
99
100
101
102
DRAWING
$ I-
2hr
1 4hr
SD
~v I I
CO TINENTAL COWL
DETAILS
Iris Damper
Fi reS moke Dam persSleeves
2hr Ratillg
With installation frame
4br Rating
Smoke damper
Intumescent Sleeve
Access Openings
Access panel - removable
Access door shy hinged
fnspection cover
Discharge Continental Cowl
44
DW154 Sp(Cii(ltJll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
DRAWINGltIC DETAns
-
I
I
~
I I I High Velocity Discharge Terminal 103 I
I
I I
J I I 1 ~--
Offset Stack Discbarge Terminal 104 1
~ I e --(-
I
N
I
I
I~
I I Vertical Oischarge with Weather Cowl 105 I
--1--1 I
I
GAPI I
RTl AL DISC) lARGE WITH W ATIIER COWL
45
DW154 SpecUicatoll for Plastics Ductwork
STANDARD COMPONE T DRAWINGS - PLA TEQUIPMENTIMISCELLANEOU
FIG DRAWING DETAILS
106 ~~~ Rectangular Attenuator
107 ~- Circular Attenuator
108
~ Beod Attenuator
109 J ~(f) Heating Coil
110 J ftte Cooling Coil
III Jc[ Electric Heating Coil
112 X F
Humidifier
113 [H XX Axial Fan
114 ~fB1famp Noo-standard Ductwork Cross hntchillg (of any separate type) indicates by reference to a key any non DVil54 ductwork system
115 2llIIIIJIIIIIll Flexible Ductwork
46
DW154 SJeCUicll(iol1 for Plastics Ductwork
TABLE 12 - STANDARD ABBREVIAT ONS
ABBREVIATION FLL
AD Acces Door
AFF Axial Flow Fan
AHU Air Handling nit
All Aluminium
AP Acess Panel
AT Attenuator
AV Air enninal Unit
BE 81ank nd
BQ Blast ate Damper
CC Cooling Coil
CF Centrifugal Fan
CTA Cross alk Attenuator
CVU Constant Volume Unit
DP Drain Point
EEC Electric Heating Coil
El Expansion Joint
FAl Fresh Air Inlet
FA From Above
FB From Belo
fBPP Fabric Backed Polypropyl-ne Sheet
Flexle Flexible Connection
lexfD Flexible Du t
C False Ceiling CO an oil Unit
fD Fire Damper
FFL Finished Floor Level
FJ Flanged Joint
FOAM Rigid Polyurethane Self xtinguishing Foam
FOB Flat on Bottom
FOT Flat on Top
GAM Galvanised after ManufacttrJc
GRP Glass Reinforced Plastic
GSS Galvanised Sheet Steel
HC Heating oil
HD and controlled Damper
HH Hand Hole
HL High Level
HVD High Velocity Discharge
IC Inspection Cover
ID lri Damper
IFS Intumescent Fircleevc
47
DW154 Specification for Plastics Ductwork
TABLE 12 - STANDAR ABBREVIATION CONTINUED
ABBREVIATION
IU
L
tv1D
MS
NRD NTS
OBO
OE
PHD
PD
PP
PP
PRD
PVC
RFC
RSC
R
SBO
SO
S1 TST
SSL
TA
TB
TO TJ
TP
TV
TV
OS
UPVC
S
V
VAV
50 RSA
FULL
Induction Unit
Low Level
Motor controlled Damper
Mjld Steel
on Return Damper
at to cale
Opposed Blade Damper
Open End
Parallel Blade Damper
Pneumatic controlled Damper
Polypropylene
Self xtinguishing Polypropylene
Pressure Relief Damper
Polyvinyl Chloride
Rolled Form Chamlel
Rolled Steel Channel
R fUnit
Singl Blade Damper
Smoke Damper
Slip Joint
Stainl t el
tructural Slab Level
To Ab vc
To Blow
Top Down (In Direction of Flow)
Telescopic Joint
Test Point
TU111iog Vane
Top Up (In Direction of Flo )
Voles Otherwise Stated
Unpl3sticisecl Polyvinyl Chloride
Underside
Ultra Violet Light
Variable Air Volume
Rolled Steel Angle (Vith Size)
48
DW154 SJeriiflllioll for Plastics Ductwork
A2 DUCT PRESSUREAPPE DXA Ductwork con truct d to DWIl54 will bebullbullbullbullbullbullbullbullbullbullbullbullbullbull
Air Leakage From Ductwork To be read in conjunction with DW143 A practical guide to Ductwork Leakage Testing
CAUTION As highlighted ill both this docul1lenr and DW14 I lot ellough emphasis can be placed 01 the fact that except for high pressure class C the much more stringent ductwork constructional standard brolght about b the general acceptance of DW154 have irtlally negated the requirement for leakage-testing It is essential lO realise lhat except where it is mandatory this doclllllelll is nOl an endors ~lIlent of the rourine testing of ducts bllt purely a guide to outline the procedures for cononnity with the air leakage limits ill Table l Where the specified methods of assembly and
A3sealing of dlcls are u ed a vi ual inspection wil ordinarily sl~fll e for ver(iatioll of a well engineered and a ceptahfy airtight COl1strucrioll WHERE NOT MANDATORY DUCT LEAKAGE TESTING IS GENERALLY AN UNJUSTIFIED AND SUBSTANTIAL EXPENSE
A1 INTRODUCTION L akage from ducted air distribution systems is an Lmportant consideration in the design and operation of ventilatjon and air conditioning middotystems A ductviork t)ystem tbat ba limited air leakag within defiucd limits wiH cnsUft
that tile design characteristics of the sytem can be maintained It wilJ also ensure that energy and operatLonal cosb are maintained at optimum levels DucLwork constlucted and Ulstalled in accordance with DW154 should minimise a level of air leakage that it) appropriate to tll operating static air pre sur in tile system
A4However it is recouuised that tbe environment in wtJich middotystems are installed is not always conducive to achieving a predictable level of quality in term of system ajr leakage and it is therefore accepted that designer may sometimes require tlle ystem to be tested in part or in total It should be ecogni ed that the testing of duct systems add a ignificant cost to the installation and incur some extra tjm within the programme (Se 47 and 64 re mandatory te-sting)
manufactured to a structural standard that is compatible with the system operating pressure There are three classes of duct con truction to eorre pond with the three pre ure clas meations Class A Lo pressure ducts suita le for a maximum positive operating pressure of 500 Pascal and a maximum negative pressure of -500 Pascals Class B IVledium pressure ductmiddot suitable for a rnaxilnuJJl positive operafjn o pressure of 1000 Pascals and a maxllnum negative pre sure of -750 Pa cal Class C High pre sure ducts suitable for a maximum po ilive operating pressur of 2000 Pa cals and a maximum negativ pres ur of -750 Paltcals
LEAKAGE FROM DUCTWORK Leakao-e front pia tic air ducts occur at the joint~ and is therefore proportional to the total surface area orthe du twork in th system Tb level of leakage i imilarly related to tIle air pres ure in th du t system and whilst there LS n precis formula for calculating the level of air los it i generally accepted that leakage will increase in proportjon to pressure to rbe pOvver of 065 The effect of air leakage from high pressure velocit ductwork is critical tn terms of system perfomlan dege energy consumption and the risk of high frequency noise as ociated with leakage These problems are le critical with medium pressure 10 ity systems but should be con idered Low pres mevelocity ducts present the lowe~t
ri k in tenn of tbe effect of leakage on the operation of the s stern
SYSTEM LEAKAGE LOSS As there i no di ct relatLonship between th volume of air conv yed and the surface area f the ductwork sy tern required to match the building configuratmn it is difficult to express air leakage a a percentage of total air volume Similarly the operating pressure will vary throughollt lh 3 system and a leakage is related to pre me the calculations ar comple However it is generally ac epted tbat in typical good quaJjty systems the leakage from
49
DW154 Specificatioll for Plastics Ductwork
each class of duct llnd r operating condition will be io the region of CIa S A low pressure 6 Clas B medium pres un 3 Clas C high pressure 2
A5 SPECIFYING AIR LEAKAGE TESTING Re peeting both the co -t and programme implications a sociated with te ling du 1 for leakage the designer may for example indicate that a particular system is te ted as follow
a) High pressure ducts - all tested b) Medium pr ssure duets - 10 of the
ductwork shall be s eet d at random and tested
c) Low pre sure - unte ed In any case where a random te t i elected for medium pre sure ductmiddot the followin c1au~e is suggested for inclusion by the de ign r
The designer hall elect at random a maxirnwlI of 10 of the dUCl system to bt tested for air leakage The duct hall be tested af the pressure recommended in Table J3 for the assifi atiol for the ectiol1 of the ductwork that is to be tested The tests shall be carried Ollt as the work proceeds and prior to the application of thermal insulation In the event of test failure of the randomlY selected section the designer shall have The right to select two La1her e tiolls at random for resting Where succes ive failures are identified there shall be a Tight to require rhl COl11raCWr 10 apply remedial attention to the complete ductwork system Th contractor shall provide documented eviden e of the calculalions used to arrive (1
the allowable 10 I for the section to be tested and the client or his agent shall willess and sign the results of the test
able 13 Air leakage rates
Maximum leakage of duct work Static
prcssUft Low-pressure edium-prc-sure I Iigh-prebull me diJfercntial Class A Class B Class C
1 2 J 4 Pa Litres per second per quare metre of surface area 100 054 018 ZOO 084 028 300 110 037 400 132 044 500 153 051 600 058 019 700 064 021 800 069 023 900 075 025
1000 080 027 1100 1200 1300 1400 1500
029 030 032 033 035
1600 1700 1800 1900 2000
036 038 039 040 042
Note Recommend d mean test presures are highlighted iD bold type with the actual selection being left to tll test operator
50
DW154 Sfeeiieaioll for Plastics Ductwork
A9
A10
and air leakage classification for the y em under test
DESIGNERS CALCULATIONS The designer can middotaJculate with reasonable accuracy the predicted total loss from a ystem by
a) Calculating the operatin presure in each ection of the sy tern
b) Calculating the surface area of the ductwork in each correspondin pre lire s ction
c) Calulating the allowabl~ los at the operating pressure for each ection of the system (see table 13 for allowable leakage figures)
VARIABLE PRESSUR S IN SYSTEMS De igner can achieve significant co t saving by matchina operating pressures throughout the system to constmctional standard and appropriate air leakage testing eO the practice of specifying construction tandards for whole duct sy tems based on fan discharge pre sure may incur unnece sary costs on a project For example ome large sy terns ould well be classiC ed for I akage limits as follows
Plant room risers CJas C Main floor distriblltJou CIa B Low pre sure outlets Cla A
A6 SPECIAL CASES There may be ~itLlations on a project where circumstance dictate thal pecial consideration be given to containing air loss s eg a long mn of duclwork may incur a di -proportjonate level of air 10 s In ca es such as thi example the designer can specify an improved tandard of airtighmess ie 80 of alJo~able 10 s for la B Ju ts The designer sbould not specif a CIa C t sI at CIa s C pressure for a CIa s B ducl
A7 SUGG S ED RANGE OF TES ING
A8 TESTING OF PLANT ITEMS Items of inline pJant (eg Fig 106 to 115) will not normaUy be included in an air I akage test The dllctwork contractor may indud such itelllS in tbe te t jf rh quipm ot has a certificate of COnfOlnlity for Ihe pres ure clas
bull High pressure duct bull Medium pre sure ducts bull Low pre sur ducts bull Exposed extract syst ID bull Ceiling void extract
systems bull Secondary ducts from
VAV or fan coil units bull Flexjble duct bull Final connections and
branches to grille and diffusers
100 test See A5 Untested UDt sted
Untested
Untested Untested
Untested
SI
i
DW154 SJecijicafion for Plastics Ductwork
ig 116 Permitted leakage at various pressures
Leakage in litres per second per square metre duct surface area
Vgt
o ltgt 0 ltgt N
ltgt Cgt
0 0 cc
0 0
~
g =
g ~
c 0
J
ltgt 0 I
~ ] tn
ltgt ltgt
In ol
~ 0 ~ 8 ~
~
c ltgt ltgt
~ CJ
~ ~ ~ ~ 8
0shyij
~ ~ ~ t
ltgt ltgt 00
l
~
~ Q
c C
~ rshy
e ltgt
I 1
I Cgt ltgtv
c Co ~
~~ ~ 10
I
0 Cgt
fJshyq 410 ) 1 ltgt
ltgt N
~ shy ltgt ltgt
~ I 1
c
52
DW154 Specificatio for Plastics Ductwork
Example of a completed test sheet Test No
General
Name of job N~ jC43Pt(r2lef Building Repound ~(~~0
Part 1 - Physical details
a Section of duct work to be tested ~(diffPIfff~el1f3rd Floor
b Drawing Number g91~~ c ssure aSSJ L atlOn V~Jl~IRfYgtg~~lPre Cl T Class C
d Test static pressure -(9 raErq~ ~~~~-~~J~~~ ~~ ~~~~ll
Leakaoe factor 9~-tre3$ecMz I OM REFTOTABLE 13)e b bullbullbullbullbullbullbull
f Surface area of duct under test Q~tJJItetre$ CPROMCALCU TIO BELOW)bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull ampampamp bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull
g ]Vlaxi mum permitted leakage -~ (~i~~0 ~~r~~ ~~~l-~-11~ ~~~Q
Part 2 - Test particulars
a Duct static pressure reading 9QFt~q~ ~ middot~~~1 ~~
b Manufacturer and type of liow measuring d vice (-~~~cJ~Y-9Q7EYg c Range of measurement of now measuring device QtP)OQ~(e~~~0I~~~~1~I~ ~~~~~~W~
d Reading of flm measurin o device pmiddot IFROM RIO)ftscag ~
I (DERlVED [ROM CHART SUPPUED WITH RIG US 0 ud)1e Interpreted air flow leakage rate ~(~~~f~~~ (~l~~~~~~~~~~~~~~~~~I
f Duration ~~~~~norn~allY l~ lnil1Ut~~d~~~ it1~ W~ Date of test ~(lITled ut by Wltll s ed by ~ ~
(~lJ MIJLrr) (Si~rrfltJUYJ
Printed Name 1~g0f~ Printed Name ~~Y~9~ and Company 7jl~~~~~( UJd CompanY AB COII$Itallt8
Width and depth or diameter
Periphery ength Area
millimetreS millimetres metre qL1are metre
800 x 750 3100 1755 5440
600 x 650 2500 557 1193
300 x 300 1200 120 144
305 din 958 700 670
250 dia 785 450 353
TOTAL 8000
53
DW154 Specijilarion for Plastics Ductwork
pA XB
Guida ce No es For he ransport Handling and
Storage of uctwork
avoid damage to adjacent duct panels In somc ca es particularly on con acts calling f r repetitive sizes the use of timber jigs and spacers may be justified Where reduced bulk and greater protection are major factor such as consignments for export transporting ductwork in L shape sections may justify the increa ed ite as embly co ts
It is recommended that before a contract is finalised that consideration is given to the subject of site acces material handling and storage as tbcy havgt a strong influence on the cost efficiency of the overall activity of ductwOlk installation
B3 Handling To minilnise th risk of damage duct sections should be clearly identified and deliveries to site should be closely linked to the installation programme so as to avoid accumulation of
B1 Storage and Handling of Ra Material Material should be stored in suitably designed racking out of direct unJight Where possible the e racks should be metal to earth Edges of cut she t may be harp and protective gloves are advised Wearing teel toe-capped boots is recommended Most pIa tic sheet is manufactured with smootb mfaces andor is suppLied with protective coating Care must be taken to prevent accidental lippag of stacked materials Beiuoshy good electrical insulators the movement of stock unless earthed will allow the build up of stati All stock shapes are chemically stable at normal temperature Whil t some raw materials used in their manufacture may themselves pre ent a toxic hazard once incorporated into the lOck bape they no long r constitute such a hazard and no dermatitic bazard are known nor are any
unfiJied ductwork and minimise double handling It is important to recognise that ductwork panels joint and corners arc susceptible to damage and care must be taken wheu band ling such material through a site During handling individual item of duct work may be liable to light cross sectional deformation until thev become an integral pan of a completed ductwork system Whilst this may temporarily detract from its intended appearance thi deformation will not have any detrimental effect on the functionality of the finally a semblecl system Installation of duct work and asociated plant items ill illevitably involve manual handUng The responsibi Iiry of employers and employees to a ses the risk of personal injury during mallual handling operations is et out in the HS E publication L23 Guidance on Manual Handling Regulations 1992
environmental problems expected 84 Site storage
B2 fransport Large capacity vehicles with high-sided open or closed-top bodies are tlle mo t suitable for the transport of dllctwork Careful consideration should be given to the
Adequate floor space IDust be provided within tbe building for the site storage of ductvork Such storage shalt make due allowance for thc stOf(ne of ductwork in stacks such that access ~ egt
between them is of sufficient width to pennil the removal of item without interference to
unloading of transport on sit a not all siJes b n fit from the material handlino- and access facilities that exi [ in a manufacturing workshop such as crane- fork-lifts or loading bay Site handJiog facilities along with
adjoining sta ks Ductvork components should be positioned so a to avoid crushing Ductwork of small panel size may be stored horizontally however care should be exercised to ensure that tack sizes are limited 10 within
ehicular acce s restrictions may itilluence the type and ize of transport to be uWised
engtlls of ductwork should be positioned 0
the tmctural strength of the duct sections to prevent distortion of the lower sections within the stack
as to avoid crushing Lengths Witll projections such as branches and bends i1anges girths damper quadrauL should be loaded so as to
54
DW154 S1tciic(ltioll for Plastics Ductwork
85 Internal cleanliness of new ductwork The site storage of ductwork introduces the important cODsideration of maintaining the internal cleanliness of the ductwork R feren e should be made to HVCA documentshybull DWffM2 Guide to Good Practice - internal
Cleanliness of New Ductwork Installations If the above conditioDs can not be satisfied consideration should be given by tJle designer to amending the specification to include for Po t Installation Cleaning as covered by tJ1C HVCA documentshybull TRJ17 Guide to Good Practic - Cleanliness
of Ventilation Systems
APPE DIXC
Fi e Retardant inishes C1 Improvement in the fire retardancy of plastic
ducts can be achieved to varying degrees and is wholly dependent llPOll the surface coating laminating resin selected and construction specification adopted In some instances smoke emission is coILSidered equaUy with other speci fication requirernen ts of the materials resistance to ignition and bumjng It is therefore important for design rs to establ ish the clients and officers detailed requirements and not rely on a tbird party interpretation of fire resisting or fire retardant Where possible the specification should refer dir etly to compliance with a British or European Standard identifying the specific sections applicable There are various types of resin and mat rcLnforcements that can achieve a Class 1 surface spread of flame ratin o when tested according to BS476 Part 7 (1987) This test puts materials illto Class I - 4 in descending order of perfoDllance according to the rat and extent of flame spread over their surfac under standard beating conditions Materials should also be tested for flre propagarion to BS476 Part 6 (1989) Tbi tesr measures the amount and rate of heat evolved by the material when subjected to standard heating
conditions Test results are given as an index of Perfonnance (i) whicb is based on three sub indices (iJ (i1) (h) The higher the value of the Index of Performance (i) the greater is the material s contribution to fire growth The higher the value of the sub-index 0) rhe greater the ease of ignition aod flame spread The highest product performance classification as defined in Approved Document B of the Building Regulations is Class O This is acLlieved if a material surface of a composite ploduct i~ either a) composed throughout of materials of
limited combustibility or b) a Class I material which has a tlre
propagation index (i) of not more than 12 and sub-index (i l ) of nor more than 6
01 J Class 0 is not a cla$sif1cation identified in any British Standard test
There are resin system reported to be classified to Class O when tested to BS476 Pcl1S 6 and 7 however designers need to ensure that such sysrems can be applied to their proposed design In propriety resinmat system available the fabrication techniques and COITect application are critical to the integrity of the reinforcing and clas ificatiol1 For example in some systems the u e of a non-fire retardant gelcont on a fire retardant substrate would reduce the classification For further information see HVCA publication DW144 Appendix D
55
DW154 SplCijiClIliol1 for Plastics Ductwork
x Guidance otes For nspectmiddoton Servicing a d
Clean-ng Access Openings
D1 GE ERAL This appendix highlight in ummary fOI111
the acce considerations that hould be made by the design r iD terms of inspection servicing and cleaning Having considered the seop and the design of the dUCI work system relative to the guidelines outlined below the designer should clearly indicate which levels of acces should be incorporated into the manufacture of a new duct work system (See Table 14 and Note I b low it
D2 DESIGN CONSIDERATIONS
D21 In ptction and servicing requireshyments are set out in Section 15 of Lhis specification
D22 Cleaning requirements are set out in the HVCA pubUcation TRl7 Guide to Good Practice Clean Lines of Ventilation Systems and the guide tates The precise location ize and
type of access would be dependent on the type of ductwork cleaning inspection and te ting metbods to b adopted Care protection and standards of cleanliness prior LO cOlllmisionin o
are set out in th AV A publication DWITM2 Guide to Good Practice Internal Cleanliness of New Ductwork Installations and th guide state Wh re specific limits of cleanliness are required ductwork sball be cleaned after installation by a spcialist cleaning contractor It will b in the interests of tht desioner botb financially and practically to cunsider employing a specialist c1eauing contractor at tbe
outset of a contract to internally clean newly installed ductwork prior to bandover This approach would reali e the following benefit shyi) Tb actual numb r of cleaning
access panels could be detennined to suit the method of cleaning to be adopted (This may be 1 s than the maximum requiremen listed under Lev 13 of Table 14)
ii) Clear directions could b given to the ductwork contractor as to tJle size and location of cleaning access panels that are required to be fitted during the mauushyfaclunng pro s
iii) The specialist cleaning operation prior to commi ioning vould enable the cleaning contractor to verify the practical acee requirement for the future cleaning operation associated -vitb a regular maintenance programme
iv) A specialist cleaning operation prior to commissioning would allow the designer to omit from the speeilicatiolJ the DWrrM2 requirem nt for factory sealing protection wipe downs and capping-off
v) Specialist Ieall ill 0 to the measurable standard defin d in TR17 will allow an objective definition of cleanline to be achieved
Car ful consideration must be gIven by the designer to the practl aJ problems associated witb the manufacture and fitting of suitably si Led access panel on small cross section duct and on the circular faces of rouod and flat oval ducts in particular
D23 Special con ideration must be given by the de igner to the practical problems associated with gaining personnel access to heavily congested ceiling areas and multi-la red du twork systems This approach would avoid
56
DW154 Spfciication for Plastics Ductwork
the possibility of access panels being D3 ACCESS 0 IN-LINE EQUIPMENT incorporated into a ductwork system at the This appendix unly covers acc il1spection manufacturing stage that were later found in through the ductwork body adjacent to an item practice to be inaccessible for either ervicing of in-line equipment and not openings in the or cleaning activities equipment itself
able 14 Acce requirements for inspection servicing and cleaning
HVCA PUBLICATIO REFE NeE (uidtgt 10 Gund Prartict
Adjace t OW144 Cleanliness orVcnlillltio S~lcr~ fRjJ7
in-line LeyeJ 1 Level 2 Level 3 ite sequipment pcdionSen lcin~ Section d C1eaniJl( SUn(O)lnspc lion Palle ltk~m_n
2011 (minimum OiL Jubje-ct to duct ~zel (ft~ -Panels
Control Da pcrs One (inspection) 203 One 300 mm x 200 mm Both sid Fire Dampers One (sCTjdJl~) 20211 One 300 0101 x 200 mm One side HeatingCooling Coils One (inspedion) 20213 One 300 mm x 200 mm (lIpstream) Both sides Attenuators (rectangular) None required One 300 mm x 200 mm (downstream) Both sides Attenuators (circular) one retluired One 300 mm x 200 mm (downstream) One side Filter Sections One (inspection) 20212 one required Uoth sides Air Turn Vanes None requjred None required Both sides Changes of Direction None required one required One side In-Duct FansDevices One (inspection) 20213 None required Both sides l
1 In the absence of any indication by the designer only Level ) access will be jncorporated into a new ductwork system
2 Tbe panel izes associated with Lev lis I and 3 acee s ar e middottablished by reference to Section 20 of DW144 and Section 2 ofTRll7 respectively
57
DW154 Speclfifatio for Plastics Ductwork
pA XE
B-bliography Included in this Bibliography are technical pUblications which may be of interest (0 ductwork designers fabricators and erectors and to tho e in the heating ventilatlng air conditioning industries generally nquiric should be made of the relevant organisation at the address quoted Since its publication other addresse contained within 0V154 mav have changed and some pubJicalions may have been superseded
HEATING AND VENTILATING CONTRACTORS ASSOCIATION
4 Palace Court London W2 4JG Telephone 020-7229 2488 Fax 020-7727 9268
Orders fo FlY A Publications Old Matlsion House Eamont Bridge Penrith Cumbria CA 10 2BX (Telephone 01768 864771 Fax 01768 86718) Email hvcapoblicationshvwelfarecouk DWn 44 pe ilicatiun for sheet mctal duclwork (Iow- mediulllshy
and high-pressure) 1998) DWIl4 A practical guide to dUGI ork I akage te ting
(revised 2000) DWII54 Specification for plastic~ duct rk DW171 Guide to good Practice for kitchen venlibtion system DW191 Guide to good pracuce glass fibre ductwoJk DwrrMI Acceptance cheme for new products - Redangolar cro
joint classification Guide to good pra tice - Internal cleanliness of new ductwork installations Guide to good practice for the design for the Installation of lire and smoke uampers
J 1Other puhlications
HampV safely guide 5th edition JS2 Tool box talks JS5 Weldlng Safety booklet JSI9 afety facts bo klet Fact sheets 1-24 2nd edition JS2J COSHH manual volume 1 Advice on compliance with the
regulations 1521A CO I-rH manual volume 2 Asses mcnt h ets JS23 Ri k management manual TR3 BrazinltT and bronze welding of copper pipework cUld sheet
(I 976) TR5 Welding of carbon steel pipework (1980)
TR6 Guide to Good Practice for Site Pre sure Testing of Pipework (19 0) Guide to good practice cleanliness of ventilation Ylem
CHARTERED IN TITUTlO OF BUILDING SERVICES E G EERS Delta House 222 Balham High Road London SW12 9BS rTelephone 020-8675 5211 Fax 020-8675 5449) CIBSE Guide Volume A Design Data Volume B In tallatiol1 and quipment Data Volume C Reference Data
CommlssioniJIg Codes These Codes eover the preliminary checkS eUing to work and regulation of vanous catcgories 0 plan The Codes give a guide to design implications Series A Air Distnbution Systems Series B Boiler Plant
ri s C Automatic Conlrol ystems Cr1es R Refrigerating Sy terns
Sene iN Water Distribution Systems
Technkal Memonllda TM 4 Design Notes for the Middle East TM bull Design otes for Ductwork TM 13 Minimi iog lhc Risk of egiounaires Disease
Research Reports RROI95 Ventilation system hygiene - A review of published
infomlatioo on lhe occurrence and ffects of Olltamination Rl~02J95 Air-to-air heal rec v ry RR0395 rnfluen e of HV C on smoke detectors
ATlONAL ENI [ERING SPECIFICATION LfMITED Southgatc hamber 3739 Southgate Street Winchester S023 9EH (Telephone 01962 842058 Fax 01962 R(8982) BUfLDING S RVICES RESEARCH AND [ ORMATION ASSOCIATIO Old Bracknell Lane West Bracknell Berkshire RG 12 4AH (Telephone Brackl1eU (01344) 426511 Fax 01344 487 -7 )
Application Guides AGln4 De tglJing Vana~le Volume middotylans for KOOnl
iir Movement AG1I91 Commissioning of V Sylcms in Buildings 11 6194 Fire Dampers
B) 94 cntiJalion or KitcneTls
AG389 The Commls ionin of Air Systems In Buildmgs AH2192 Commissioning of Bern - A ~ode of Practice TN2417 I Fire Dampec il) Ventilating Ducl
BEATING VENTILATING A AIR CONDITION G MA UFACTURERS ASSOCIATIO (HEVAC) HEVAC Henley Road Medmenham Marlow Buck SU 2ER (Telephone 01491 578674 ox 01491 575024 Emoimiddot infofetacouk)
Publicatjons Air Diffusion Guide Guide to Air Handling Unit Leakage Testing Guide to Good Practice Air Handling Unit Real Room Acoustic ~ st Procedure Specification for the ertiiicatioll ofAir Filters Method of Test for Water Rejection PerfOnTlatce of Louvrcs Subjected 1(1
Simulated Rainfall Test Procedure for Acoustic Loo cs Specification 10 Floor GrilJes - Types Performan e and Method ofTest Specification for the Determination of the Collection Efficiency of SilJ1d
Trap Louvre Domestic Mechwlical Vclltllalion Systems with Heal Recovery Fan Application Guid
~an and Ouctwork Installation Guide Guide to Fan Noise and Vibration
pecification of Requirements for JallJral Smoke and Heal Exhausl Ventilators
pecification for Powered Smoke and Heat Exhaust Ventilators
Specification of Requirements for Smoke Curtains Design Gujue of Smoke Ventilation for Single Storey Lodustrilll Building~
Including those with Mezzanine Floor and IIi Racked Storage Warehou es - Issue 3
Guidance for the Design of Smoke entilation YSlem for Covered and Undergrollnd Car Parks - lssue 1
Application of SOloke Control Equipment and Syst m Guid to Good Practice - Isue J
58
DW154 Sp(C~tiifitiol for Plastics Ductwork
BRITISH STANDARDS INSTIT TION Sales Department 101 P ntooviLle Road London NI 9ND (felephone 020-78 1 78801)
CP 413 1973 Ducts for building ervices
SS 476 Fire tes on building matenals and lruc(ure
Part 4 19 4 Non-combustibility lest or materials
Part 6 I Fire propagation lest for materials
Part 7 1993 Surface spread of tlarnJ tesls for materia
Part 20 1987 Fir resistance of elements of construction
Part 21 1987 Fire r sistlUlce of loadbeanng elements of construction
Part 22 1987 Fhe istallceofllon-loadbearing elemcllts ofconsttuclion Part 23 1987 Contribution of componcnts to the fire resistance 0 a
structure
Part 24t987 Fire resi lance of wl1lilation ductl
SS 5588 nan 919 0 Fire Precautions III thc desIgn and OOSlnJ lion of buildings
S 729 1971 Hot dip galvanized oatiugs (or irOIl aod stcel articles
BS 1449 Steel plate sheet and Irip
Pan 11991 Carbon steel plate heel and strip Part 2 1983 Stainless steel plate sheer and strip
and
B middotENJOI49-2 996 BSEN 10149- 1991)
BSEN 10131 1992
BSEN22063 Sprayed metal coarings 1994 Protection of iron and steel by aluminium and zinc against
atmospheric cOlosion Irotectiotl of iron and ste I against corro ion and oxishydation at elevared temperatures
BS 353 1981 Glossary of lerms relnting to thermal insulation
BS ISO 1479 Self-tapplngscrewsandmetallicdri c crew
B -lSO 7049
1994
B 4800 1989 Painl colour for building purposes B 4848 l0 rolled structural steel sections
Part4 1972 Equal and unequal angles BS 5422 1990 Specification for the use of therm illuating matcriulS
SS 5720 1979 ode of practice for mechanical veutilating and air C 11shy
dirionin bull in building
l3S PR 12814-1 Bend resting for plasric welds
SS PR 12814-2 Tensile testing for plastic welds
SS PR 13067 Appro altesting for plastic welds
BS PR EN I 100-] Vi ual in pection ofplaslic welds
SHEET METAL AND AIR CONDITIONING CONTR-CTORS NATIONAL ASSOCIATION INC (SMACNA) Headquarters 420 I Lafayeue Center Drive Chanlilly Virginia 2051-1209
Mailing Address pa Box 221230 Cbantilly Virginilt120 153-1230
Telephone (703) 803-2980 Fax (703) 803-3732
Accepted IJJdustry Pl3Gtice for Industrial Duct Constnlelion 197 ) i-rchitecmral Sheet kwl Manual ([993)
Comractors Guide lor Modification 10 ooslruerion Colllraets 1993 Ducted Eleclric Heat Guide for ir Handling Ssrerns (1994)
En~rgy ollservatioD Guidelines (1984) Energy Recovery Equipment yslClllS (199l
Fibrou GIns Duct onS1ntClion Standards (1992)
Fire Smoke amp Radiation Damper In tall Guide for HVA Syst ms (1992) Guide t leel Stack 1(95)
HVA Air Duct Leakage Test Manual (19 ) HVA COlllmissioning lvlanual (1994)
H A Duct Construction Standards-Metal amp Flexible (1995) Addendum 01 (Nov 1997)
HVA Duct Systems Inspection Guide (1989)
HVA ySlems-Application (1986) nVAC ByternS-DLlct D ign (1990)
HVi Systems-Testing Adjusting amp Balancing (1993)
indoor Air Quality Manual (1993) tcheu quipment Fabrication Guidelmes (1990)
Managers Guide for elding (1993)
Rectangular Industrial Duct Cons1TUction Standards (19 0) Round Industrial Duct oustmction Standards (1977)
Sei mic Restraint Manual (1991) (wl Appendix E 1993) SMACNA Ma le Index ()fTechnical Publications (1995) Tbennoplnstic Duct CPY ) Construction Manual 1994)
DEPARTME OF THE ENVIRO MENT (Publications Centre) H Stationery Oflice 5 Nine Elms Lane London SWS 5DR
MampEJ 011972 Electrical in tallat1011 in buildings ( ew Editiou)
IampE 0319 Healing hot and cold wat r steam and gas losla1lations for buildings
M amp - No4 1970 Central heating and hot and cold ~ ateT in tallations for
dwelling
M amp ENo100 1971 Mechanical ventilation for building~
ASSOCIATION FOR SPECIALIST FIRE PROTECTlO As ociation House 235 Ash Road AJdershot Hampshire GUl2 4DD
Telephone OJ25221322 Fax 0 J252 333901
lublicalioos Fire Ratcd and moke Outlet Ducrwork An Industry Guide t Design and InSlalla lioll
HEALTH AND SAFETY EXEC TIVE Rose Court 2 Southwark Bridge London SEl 9HS Telephone 020-7717 6000
TWJ THE WELD G TlTUTE Abington Hall Abington Cambridge CB16AL Telepbone 0 J223 89162
Publication DatJ Oil w~ldll1g of lhermopla lics
59
DW154 wciiwlioll for Plastics Ductwork
A -=--DIX
Factors
Specific gravity shy pp = 091 approx UPVC = 14 approx
Some miscellaneous conversion factors
To convert
Length Inches to millimetres Feet to metres
Multiply by
2540 03048
To convert
Millimetres to inches Metres to feet
vIultiply by
003937 3281
Area Square inches to square millimetres 6452 Square millimetres to square inches 000155 Square feet to square metres 00929 Square metres to square feet 10764
Volume Cubic feet to cubic metres Cubic feet to litres Gallons (UK) to litres
002832 2831 4546
Cubic metres to cubic feet Litres to cubic feet Litres to gallons (UK)
35315 00353
022
Mass Ounces to grams Pounds to kiJograms Tons to tonnes
2835 04536
1016
Grams to ounces Kilograms to pounds Tonnes to tons
003527 2205
09842
Volume flow Cubic feet per minute to cubic Cubic metres per second to cubic
metres per second 0000472 feet per minute 2119 Cubic feet per mIDute to litres Litres per second to cubic feet
per second 04719 per minute 2119
Motion Feet per minute to metres per second 000508 Metres per second to feet per minute 197
Pressure Inches water gauge to millibars 2491 Inches wateJ- gauge to pascals (Pa) 2491 I Pa = I ewton per square metre = 10-2 millibars
60
Heating and Ventilating Contractors Association Esca House 34 Palace Court London W2 4JG
Tel 020 7313 4900
e-mail contact Itvcaorguk web site wwwhvcaorguk
Fax 020 7727 9268
DW154 SpedjimioTl for Plastics Ductwork
22 THERMAL INSULATION
221 The provision and application of thermal insulation to ductwork is not the responsibility of the ductwork contractor
222 Where ductwork is required to be preshyinsulated the specification should be agreed with tbe designer
223 Where the temperature of the air within the duct promotes condensation on the exterior surface of the duct and cause moisture penetration througb the thermal insulation vapour scaling may be required and in this case the most important requirement is to limit penetration of the seal
The extent of any vapour sealing of ductwork thermal insulation and the support method to be u ed must be clearly pecitled in advance by the designer
224 For detailed information on the thermal insulation of ductwork reference should be made to BS 5422 1990 which covers the specification for thermal insulation materials on pipes ductwork and equipment (in the temperature range -40degC to +700degC) and BS 5970 1992 which is a Code of Practic for Thermal Insulation of Pipework and Equipment (in the temperature range -lOOdegC to +870degC)
23 FIRE RETARDANT FINISHES ON PLAST C DUCTWORK
231 The designer should note tbat ductwork constructed to DW154 has no teted fire rating or information see Appendix C
24 REINFORCEMENT OF DUCTS WITH GRP LAMINATE
241 General Where ductwork is required in larg T izes than are covered by Tables 2 4 6 amp 7 or with the increased strength sometimes necessary for industrial use external reinforcement is normally pwvided by applicatioD of glass fibreresin laminate
GRP systems will bond satisfactorily with standard UPVC sheet but for pp it is
nece sary to use a specially prepared sheet with a glass fabric backing incorporated dOling manufactllfe
The detailed techniques of fabrication using GRP are outside the scope of this speci lcation but the following notes are offered for guidance of ductwork fabricators
242 Materials
2421 Quality The laminate is made up of polyester resin complying with BS 3532 and glass fibre complying with BS 3496 or BS 3749 The nominal ratio of resin to glass fibre should be 7030 by weight
2422 Minimum properties The laminate shall comply with the followiog mini mum pbysical properties
Tensile strength - 70 MNm Tensile modulus - 7 Gl m Flexural strength - 140 M Im Bond strength (hetween laminate and substrate Not less than 7MNm Bmcol hardnes Not le s than manufacturers specification
The GRP reinforcement educe the expansion of the parent material but the resultant stre ses arc well within rhe strength of the bond However the Iinear thermal expansion curve shown in Figs 34 amp 35 will serve as a guide
Surface resistivity electrkal propcltles and acoustical propertie are similar to the relevanl unreinforced materials The fire retarding properties of GRP may be improved by the use of specialisl laminating resin
2423 Forms available GRP Laminate should be built up from the separate materials ie resin aod glass fibre in the form of chopped
I strand mat or spray ravings
28
DW154 Spcification for Plastics Ductwork
2424 Workshop conditions Polyester resuls are sensItIve to lmperature and the workshop hould b maintained at a temperature of herween 20deg and 25degC HiOh relative humidities and damp onditions should be avoided A good rate of air change must be pro icled pJeferably by m chanical ventilation
2425 Storage of materials Resin and urin o agents shouJd be stored in dark cool condirions away from the working area and in confonnit with statutor requireshyments for tJle middottorage of flarmnable liquid Because of Ule Limited torage lif of the unmixed resin and curing a eot mal lials ~hould be ch eked before use to enLlfe that they are within the manufacturer pe ified sh If life (usually ix month from the dm of manufacrure)
Glass fi re should be stored separately und r clean dry conditions
243 Surface preparafon
2431 UPVC To achieve the specified bond strengtll the urface to which the GRP is applied mut first be thoroughly cleaned and then etched either by mechanical means or by the use of a suitable solvent
2432 pp with glass fabric backing To achieve the specified bond middottrength the fabric backing must be thoroughly impregnated Witll resin
244 Mixing the materials for use The re in 1 a three part mix compri lng base I sin hardener and accelerator The manufactur rs pecj[ied proportions are critical and th llUxmg sequenc pecified must be meticulously foUowed
The resin has a very limited life after mixing and before u e It is dependent on the characteri tics and bulk of th resin the alllount of hardener the degree and method of acceleration and the workshop onditions
245 Methods of application
2451 General The mixed resin may be applied by hand or b pray c1epoition The operation must b completed within the gel time of th y tern and tbe laminat fully cOI1olidated to achi v the phy ieal properties pecified
2452 Hand lay-up The duct surface i coated by hand with resin Llsing a brush and a mar of gla fibp orked in until full consolidation achieved Th proc is repeated untiJ th requird thicknes i obtained
2453 Spray depo Won The duct surface is coated WiUl re in by spray gun with the chopped glass roving added through a separate nozzle The full thickne i obtain d in layer with con olidation of each layer by hand roller
246 Construction
2461 General M ini mum COllst ructional requireshyments are pe itied ill Tabl 10 for rectangular and Table 1J for circular dUClS
2462 Joints and stiffeners Fig 29 30 31 32 amp 33 hoI TOSS
joint and tiffener for reinforced UPVC and PBPP duct
247 Worki g practices The fabrication of ductwork pecifiecl ill thi document i not affected by the addition of GRP
29
DW154 SfJcdJicatiOt for Plastics Ductwork
Table 10 Minimum constructional requirements shy
Longer Side Minimum Sheet Thicknes and
GRP Reinforcement
UPVC FBIPP 1 2 3
mm mm mm Up to 1000 3 plus 3 plus
06 kgm2 06 kgOIl GRP GRP
1001 to 2250 45 plus 3 plus 06 kgm 12 kgm
GRP GRP
2251 to 3000 45 plus 6 plus 12 kgm 12 kgm
GRP GRP
Cross Joints
UPVCFBPP 4
mm socket amp spigot
as Fig 30 or flanged as Fig 29
75 x 9 flange welded on both sides as Fig 29
75 x 9 tlange welded on both sides as Fig 29
rectangular GRP reinforced ducts
SlifTeners Maximum Spacing Between
JointsSljffeners UPVCIFBIPP UPVCFBPP
5 6 mm mm
75 x 9 flat 800 as Fig 31 or
50 x 50 x 5 plastic or MS inverted angle as Fig 32
or tormer as Fig 33
75 x 9 flat 600 as Fig 31 or
50 x 50 x 5 plastic or MS inverted angle as Fig 32
or former as Fig 33
75 x 9 flat 600+shyas Fig 31 or 50 x 50 x 5 plastic
or MS inverted angle as Fig 32
or former as Fig 33
Note 1 On rectangular duct up to 400 mm longer side no stiffeners are required 2 Applies to Tables 10 amp I I For COlJstructional operating temperature limits refer to Part 2 clause 5A 3 Tables 10 amp II apply to all pres ure classes up lo ]500 Pa
Table 11
Diameter
1 III
lJp to 1000
1001 to 1750
1751 to 2500
Minimum Sheet Thickness and
GRP Reinforcement
UPVC FBPP 2 3
mm mm 3 plus 3 plus
06 kgm 06 kgm GRP GRP
45 plus 3 plus 06 kgm2 18 kgm
GRP GRP
6 plus 6 plus 12 kglm2 18 kgm1
GRP GRP
Cross Joints
UPVCFBPP 4 III
socket amp spigot as Fig 30 or flaoged as Fig 29
75 x 9 flange welded on both sides as Fig 29
75 x 9 flange welded 00
both sides as Fi 29
inforced ducts
Maximum Spacing Between
JointsStiffeners UPVCIFBPP
6 mm 2400
800
600
Stiffencrs
UPVCFBPP 5
mm 50 x 9 flat as Fig 31
75 x 9 flat as Fig 31 or former as Fig 33 75 x 9 tlat as Fig 31 or t()rmer as Fi 33
ote On extruded tube tip to 600mm diameter no stiffenergt are required
30
DW154 Specificatioll for Plastics Ductwork
G - Cross joints and tiffeners
Fig 29 Flange Joint Fig32 Stiffener shy inverted angle
M artiPfCuQkbdd erttpObri) Wl111 RP tlddtlt
_- GRPloliu] lh~
Fig 30 Socket and spigot joint Fig33 Stiffener shy use of former
Fig 31 Stiffener Flat
I Pv FlPP ~ ~lmJaDUA1) d
OMrlQ rrnall 1( tQlS
25 STANDARD COMPONENT DRAWINGS AND ABBREVIATIONS
251 The illustrations in this section not only highlight where applicable geometric limjtations for the de ign and manufacture or ductwork components but also recommend
standard drawing representation terminology and abbreviations for both duetwork components and some of the more commonly used ancillaryplant items
252 Designers and surveyors should note that bills of quantities should provide a full description
3)
---
v
DW154 Spcc(fim(ml for Plastics Ductwork
Fig 34 Linear Thermal Expansion
u c 0 N ro 0)
b 0)
S
sect0
5 oS cl) 0)
~
on ~ ltl
c U
-30 -20 -10 0 10 20 30 40 50 60 70 80 90 TEMPRATURE C
~ V
-
~~c_ ~
~V
V ~
-7 ~
-- ~V ----
v
-6
+14
+12
+10
+8
+6
+4
+2
0
-2
--4
ig 35 Typical Design Stress tor UPVC and P
7
6
r shy 5E
-c E----0 4t) VJ 0)
ci5 0Jl 3
~
0)
Cl
2
1
o
UPVC
1
000
1
1
pp
- r-- shy r----- shy - t--shy I
__0
-30 -20 -10 0 10 20 30 40 50 60 70 80 90 TEMPERATURE C C
Note Figso 14 amp 35 shaded area refers to GRP reinforced duct
32
DW154 Speciicfltirm for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - REC ~NGULAR
Splilt~r Posilion W-mm pliucr
A B c 40]--QOO 1 W - -
601-1000 1 W4 Wf2 -
1001-1800 3 WI W3 W2
FIG DRAWING DETAfiS
tU]36 ATI Straight Duct with socket and spigol joint
rn [037 Straight Duct with flanged joints
[I []38 Straight Duct with flanged joints
rkJ Short Radius Bend
39 Applies to any augl and for duct up to 400 n11n wide
Minimum (I1m31 radills = 100 mm
Medium Radius Bend (a illustrated)
[kJ Applies to any angle
40 Long Radiu Bend Similar but radius = W
Throlll radius = W2 Applies to any angle
- Short Radius Bend with plitlers
I -shy -shy u co - t lt Li--_ 41 t 0 ~ I I I
~ I
L 1W
Minimum waal radius = 100 mm Splitters not required in bend angle less than 45deg
42 QJ1 Square Bend with turning vanes ij
3
DW154 SP(L~ficatioll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - RECTANGULAR
FIG DRAWl G DETADS
43
~
I v
L L Radius Tee with internal deflectors
44
~ Radiussed Twin Bend
45
Imiddot
er Swept Branch
46 U-
Sqoare Tee with Turning Vanes
47
~ f
Breeches Piece
48 0 y l Piece
34
DW154 Specificatioll for Plastics Ductwork
STANDARD COMPONENT RAWINGS - ECTANGULAR
55
54
51
50
53
52
49
FIG
~MX
RAWlNG
DmiddotMAX
EfjMAX
Minimum throat rndius = 100 mm
Rectangular shy Round Transformatioll
Eccentric Taper 225deg max in either plane Spliller are required for angles greater than 225deg and hould bi eet the angle between any side and duct centreline
DETATLS
Angled Offset
OUset Taper Splitters are required for angle greater than 22 0
and shoold bi eet the angl between any side and dUCI centrelinc
Mitred Offset
Concentrk Taper 2250 max in ither plane SpUtters are required for angle greater than 225deg and should bisect the angle between any side and duel c ntreline
Radiussed Offset
35
DW154 Splcilcuthm for Plastics Ductwork
STANDARD COMPONENT DRAWINGS ~ RECTANGU AR
Branch ducl DimCllsions widlh (W) (A)
urnl mm up lO 200 75
300 100 400 125 600 150
Ocr 600 200
FIG DRAWlNG DETAILS
56 poundplusmni~~ Rectan~lar - Flat Oval Transformation
57 [ Square Branch
58 er Angled Branch
Branch dUCI Dimensions wfdth (W) (A)
[- mm mm59 3shy Shoe Branch Up (0 200 75
--shy AIshy + 300 100
400 125
450 MAX 600 150
Over 600 200
Branch duct DimensIOn
rP X width (W) A)
60 - 1--shy _
~ mm mm
Bell Mouth Branch pto 200 75 300 100 t 400 125
600 150 Over 600 200
0=0 61 -
~ Bell Mouth
- shy T 4-5deg M x
--I 1-shy
TJ
62 X I ] I
Tele-scopic Joint I Illustrated with flangeL
X63
SBD Single Bladed Damper
36
---
DW154 Spedicatioll for Plastics Ductwork
STANDARD OMPONENT DRAWINGS - RECTANGULAR
DRAWING DETAILSFIG
64 on-Return DamperNRD shyshy
shyXbull
Multi-Leaf Damper Can be piggoted or flanged oppo cd or parallel blade
Alternative controls areshy
q p [gtshy
J HD65 Hand
~MD otori ed
PO Pneumalic
L-lt
l 13G 66 Blast Gate DamperX X
FireSmoke DampersSleeves
211r Ratinggtshy----
L_-
---
----
r----
Ir-- shy
IL- _-l
2hr
With i tallation frame
67 41 r Rating
4hr
Smoke damper SD
Intumc cent Sleeve L-d
37
DW154 Specijicutiolt for Plastics Ductwork
FIG
68
69
70
71
STANDARD COMPONET DRAWINGS shy REC ANGULAR
DRAVING DETAILS
gtshy Access Openings
AP 6 Access Panel - Rerno able
w [ ~ Access Door - Hinged
I ~le Inspection Cover
le -I reg -lt
~X X Flexible Connection
~ Drop Cheeked Radiussed Twin Bend
U Drop Cheek Bend
I
72 Air Flow SymbolX
38
DW154 Specifim[ioll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - ECTANGULAR
FIG DRAWING DETAILS
73
74
75
76
77
Q
Q
rp---t
~
V- I Ir---I
JL --11
THE ABOVE DETAILS TYPICAL PLENUM
Air Terminal Plenums
Plenum with side connection
Plenum with top connection
Cover plate with connection
Special plenum with connection
elescopic conn ction in direction of air flow
39
DW154 SpecijicotiOll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG
78
79
80
81
DRAWING
-23~---pound3-(MALE) (FEMAJE)
-t=j--_j(--d-shy
--L
~ THROAT RADI S= D AS T NDARD
e ~
THROAT Rjf)lU = D A MU)
DETAILS
Straight Duct With male and female connectors
Straight Duct With flange joint and slip joint
Bend MouldedIFormed Applies to any angle ego 30deg45deg60deg90deg Medium radius bend as illustrated Long radius similar but throat radius 0
Segmented Bend 90deg four section minjmum as illustrated
Other Angles 60deg = 3 sections 45deg = 3 sections 30deg = 2 sections
I
i
40 shy
DW154 Speciicafinll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG DRAWING DETAlLS
82 Segmented Twin Bend Radius = D2 max
May also be fabricated from tube
83 Equal Tee MouldedIFormed
84 -~ 1in Bend MouldedIFormed
85 Taper Concentric 1 0 as iUu trated Eccentric 30deg iJJcLuded angle
86 Short Taper
41
DW154 SpcUicatol1 for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG DRAWING DETAILS
87 30 max Offset
Angle Branch
Bran h dUCI Dimcnsions dia (D) lA)
Shoe Branch mm mm 88 Cl
Off rectanguJur Up 10 200 75 lOO 10 400 125
- 00 150 Over 600 200
Bl1IllCh duct DimenlOns din (D) (A
~-$a-Conical Branch mm mm
89 Also acceptable with Up 10 200 r
full conical surface 300 10
400 125
END VrE -shy 600 150 Over 600 200
90
m 75
100 12 150 200
mm Up to 200
_ 300 400
600 Over 600
iUtred Branch
Shoe Branch
J-L----U ~ Bell oulh Branch
ENDV1EW
93
92
91
42
DW154 Specificatiol for Plastics Ductwork
STANDARD OMPONENT DRAWINGS - CIRCULAR
FIG
94
DRAW G
I
~ 30deg 090deg
Breeches Piece
DETAILS
95 amp-----~ Blank End
~-----p Multi-Leaf Damper Can be piggolcd or fianged opposed or parallel blade
Alternative controls areshyri=-+- L-T~
I
---
LT~
I r- -
-+1
J HO Hand96
bMD Molori cd
PD Pneumatic
tl-shy bull
Single Bladed Damper 97 ~ saD
on-Return Damper Vertical application only 98 m~D
43
DW154 Sf1tcificatioll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG
99
100
101
102
DRAWING
$ I-
2hr
1 4hr
SD
~v I I
CO TINENTAL COWL
DETAILS
Iris Damper
Fi reS moke Dam persSleeves
2hr Ratillg
With installation frame
4br Rating
Smoke damper
Intumescent Sleeve
Access Openings
Access panel - removable
Access door shy hinged
fnspection cover
Discharge Continental Cowl
44
DW154 Sp(Cii(ltJll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
DRAWINGltIC DETAns
-
I
I
~
I I I High Velocity Discharge Terminal 103 I
I
I I
J I I 1 ~--
Offset Stack Discbarge Terminal 104 1
~ I e --(-
I
N
I
I
I~
I I Vertical Oischarge with Weather Cowl 105 I
--1--1 I
I
GAPI I
RTl AL DISC) lARGE WITH W ATIIER COWL
45
DW154 SpecUicatoll for Plastics Ductwork
STANDARD COMPONE T DRAWINGS - PLA TEQUIPMENTIMISCELLANEOU
FIG DRAWING DETAILS
106 ~~~ Rectangular Attenuator
107 ~- Circular Attenuator
108
~ Beod Attenuator
109 J ~(f) Heating Coil
110 J ftte Cooling Coil
III Jc[ Electric Heating Coil
112 X F
Humidifier
113 [H XX Axial Fan
114 ~fB1famp Noo-standard Ductwork Cross hntchillg (of any separate type) indicates by reference to a key any non DVil54 ductwork system
115 2llIIIIJIIIIIll Flexible Ductwork
46
DW154 SJeCUicll(iol1 for Plastics Ductwork
TABLE 12 - STANDARD ABBREVIAT ONS
ABBREVIATION FLL
AD Acces Door
AFF Axial Flow Fan
AHU Air Handling nit
All Aluminium
AP Acess Panel
AT Attenuator
AV Air enninal Unit
BE 81ank nd
BQ Blast ate Damper
CC Cooling Coil
CF Centrifugal Fan
CTA Cross alk Attenuator
CVU Constant Volume Unit
DP Drain Point
EEC Electric Heating Coil
El Expansion Joint
FAl Fresh Air Inlet
FA From Above
FB From Belo
fBPP Fabric Backed Polypropyl-ne Sheet
Flexle Flexible Connection
lexfD Flexible Du t
C False Ceiling CO an oil Unit
fD Fire Damper
FFL Finished Floor Level
FJ Flanged Joint
FOAM Rigid Polyurethane Self xtinguishing Foam
FOB Flat on Bottom
FOT Flat on Top
GAM Galvanised after ManufacttrJc
GRP Glass Reinforced Plastic
GSS Galvanised Sheet Steel
HC Heating oil
HD and controlled Damper
HH Hand Hole
HL High Level
HVD High Velocity Discharge
IC Inspection Cover
ID lri Damper
IFS Intumescent Fircleevc
47
DW154 Specification for Plastics Ductwork
TABLE 12 - STANDAR ABBREVIATION CONTINUED
ABBREVIATION
IU
L
tv1D
MS
NRD NTS
OBO
OE
PHD
PD
PP
PP
PRD
PVC
RFC
RSC
R
SBO
SO
S1 TST
SSL
TA
TB
TO TJ
TP
TV
TV
OS
UPVC
S
V
VAV
50 RSA
FULL
Induction Unit
Low Level
Motor controlled Damper
Mjld Steel
on Return Damper
at to cale
Opposed Blade Damper
Open End
Parallel Blade Damper
Pneumatic controlled Damper
Polypropylene
Self xtinguishing Polypropylene
Pressure Relief Damper
Polyvinyl Chloride
Rolled Form Chamlel
Rolled Steel Channel
R fUnit
Singl Blade Damper
Smoke Damper
Slip Joint
Stainl t el
tructural Slab Level
To Ab vc
To Blow
Top Down (In Direction of Flow)
Telescopic Joint
Test Point
TU111iog Vane
Top Up (In Direction of Flo )
Voles Otherwise Stated
Unpl3sticisecl Polyvinyl Chloride
Underside
Ultra Violet Light
Variable Air Volume
Rolled Steel Angle (Vith Size)
48
DW154 SJeriiflllioll for Plastics Ductwork
A2 DUCT PRESSUREAPPE DXA Ductwork con truct d to DWIl54 will bebullbullbullbullbullbullbullbullbullbullbullbullbullbull
Air Leakage From Ductwork To be read in conjunction with DW143 A practical guide to Ductwork Leakage Testing
CAUTION As highlighted ill both this docul1lenr and DW14 I lot ellough emphasis can be placed 01 the fact that except for high pressure class C the much more stringent ductwork constructional standard brolght about b the general acceptance of DW154 have irtlally negated the requirement for leakage-testing It is essential lO realise lhat except where it is mandatory this doclllllelll is nOl an endors ~lIlent of the rourine testing of ducts bllt purely a guide to outline the procedures for cononnity with the air leakage limits ill Table l Where the specified methods of assembly and
A3sealing of dlcls are u ed a vi ual inspection wil ordinarily sl~fll e for ver(iatioll of a well engineered and a ceptahfy airtight COl1strucrioll WHERE NOT MANDATORY DUCT LEAKAGE TESTING IS GENERALLY AN UNJUSTIFIED AND SUBSTANTIAL EXPENSE
A1 INTRODUCTION L akage from ducted air distribution systems is an Lmportant consideration in the design and operation of ventilatjon and air conditioning middotystems A ductviork t)ystem tbat ba limited air leakag within defiucd limits wiH cnsUft
that tile design characteristics of the sytem can be maintained It wilJ also ensure that energy and operatLonal cosb are maintained at optimum levels DucLwork constlucted and Ulstalled in accordance with DW154 should minimise a level of air leakage that it) appropriate to tll operating static air pre sur in tile system
A4However it is recouuised that tbe environment in wtJich middotystems are installed is not always conducive to achieving a predictable level of quality in term of system ajr leakage and it is therefore accepted that designer may sometimes require tlle ystem to be tested in part or in total It should be ecogni ed that the testing of duct systems add a ignificant cost to the installation and incur some extra tjm within the programme (Se 47 and 64 re mandatory te-sting)
manufactured to a structural standard that is compatible with the system operating pressure There are three classes of duct con truction to eorre pond with the three pre ure clas meations Class A Lo pressure ducts suita le for a maximum positive operating pressure of 500 Pascal and a maximum negative pressure of -500 Pascals Class B IVledium pressure ductmiddot suitable for a rnaxilnuJJl positive operafjn o pressure of 1000 Pascals and a maxllnum negative pre sure of -750 Pa cal Class C High pre sure ducts suitable for a maximum po ilive operating pressur of 2000 Pa cals and a maximum negativ pres ur of -750 Paltcals
LEAKAGE FROM DUCTWORK Leakao-e front pia tic air ducts occur at the joint~ and is therefore proportional to the total surface area orthe du twork in th system Tb level of leakage i imilarly related to tIle air pres ure in th du t system and whilst there LS n precis formula for calculating the level of air los it i generally accepted that leakage will increase in proportjon to pressure to rbe pOvver of 065 The effect of air leakage from high pressure velocit ductwork is critical tn terms of system perfomlan dege energy consumption and the risk of high frequency noise as ociated with leakage These problems are le critical with medium pressure 10 ity systems but should be con idered Low pres mevelocity ducts present the lowe~t
ri k in tenn of tbe effect of leakage on the operation of the s stern
SYSTEM LEAKAGE LOSS As there i no di ct relatLonship between th volume of air conv yed and the surface area f the ductwork sy tern required to match the building configuratmn it is difficult to express air leakage a a percentage of total air volume Similarly the operating pressure will vary throughollt lh 3 system and a leakage is related to pre me the calculations ar comple However it is generally ac epted tbat in typical good quaJjty systems the leakage from
49
DW154 Specificatioll for Plastics Ductwork
each class of duct llnd r operating condition will be io the region of CIa S A low pressure 6 Clas B medium pres un 3 Clas C high pressure 2
A5 SPECIFYING AIR LEAKAGE TESTING Re peeting both the co -t and programme implications a sociated with te ling du 1 for leakage the designer may for example indicate that a particular system is te ted as follow
a) High pressure ducts - all tested b) Medium pr ssure duets - 10 of the
ductwork shall be s eet d at random and tested
c) Low pre sure - unte ed In any case where a random te t i elected for medium pre sure ductmiddot the followin c1au~e is suggested for inclusion by the de ign r
The designer hall elect at random a maxirnwlI of 10 of the dUCl system to bt tested for air leakage The duct hall be tested af the pressure recommended in Table J3 for the assifi atiol for the ectiol1 of the ductwork that is to be tested The tests shall be carried Ollt as the work proceeds and prior to the application of thermal insulation In the event of test failure of the randomlY selected section the designer shall have The right to select two La1her e tiolls at random for resting Where succes ive failures are identified there shall be a Tight to require rhl COl11raCWr 10 apply remedial attention to the complete ductwork system Th contractor shall provide documented eviden e of the calculalions used to arrive (1
the allowable 10 I for the section to be tested and the client or his agent shall willess and sign the results of the test
able 13 Air leakage rates
Maximum leakage of duct work Static
prcssUft Low-pressure edium-prc-sure I Iigh-prebull me diJfercntial Class A Class B Class C
1 2 J 4 Pa Litres per second per quare metre of surface area 100 054 018 ZOO 084 028 300 110 037 400 132 044 500 153 051 600 058 019 700 064 021 800 069 023 900 075 025
1000 080 027 1100 1200 1300 1400 1500
029 030 032 033 035
1600 1700 1800 1900 2000
036 038 039 040 042
Note Recommend d mean test presures are highlighted iD bold type with the actual selection being left to tll test operator
50
DW154 Sfeeiieaioll for Plastics Ductwork
A9
A10
and air leakage classification for the y em under test
DESIGNERS CALCULATIONS The designer can middotaJculate with reasonable accuracy the predicted total loss from a ystem by
a) Calculating the operatin presure in each ection of the sy tern
b) Calculating the surface area of the ductwork in each correspondin pre lire s ction
c) Calulating the allowabl~ los at the operating pressure for each ection of the system (see table 13 for allowable leakage figures)
VARIABLE PRESSUR S IN SYSTEMS De igner can achieve significant co t saving by matchina operating pressures throughout the system to constmctional standard and appropriate air leakage testing eO the practice of specifying construction tandards for whole duct sy tems based on fan discharge pre sure may incur unnece sary costs on a project For example ome large sy terns ould well be classiC ed for I akage limits as follows
Plant room risers CJas C Main floor distriblltJou CIa B Low pre sure outlets Cla A
A6 SPECIAL CASES There may be ~itLlations on a project where circumstance dictate thal pecial consideration be given to containing air loss s eg a long mn of duclwork may incur a di -proportjonate level of air 10 s In ca es such as thi example the designer can specify an improved tandard of airtighmess ie 80 of alJo~able 10 s for la B Ju ts The designer sbould not specif a CIa C t sI at CIa s C pressure for a CIa s B ducl
A7 SUGG S ED RANGE OF TES ING
A8 TESTING OF PLANT ITEMS Items of inline pJant (eg Fig 106 to 115) will not normaUy be included in an air I akage test The dllctwork contractor may indud such itelllS in tbe te t jf rh quipm ot has a certificate of COnfOlnlity for Ihe pres ure clas
bull High pressure duct bull Medium pre sure ducts bull Low pre sur ducts bull Exposed extract syst ID bull Ceiling void extract
systems bull Secondary ducts from
VAV or fan coil units bull Flexjble duct bull Final connections and
branches to grille and diffusers
100 test See A5 Untested UDt sted
Untested
Untested Untested
Untested
SI
i
DW154 SJecijicafion for Plastics Ductwork
ig 116 Permitted leakage at various pressures
Leakage in litres per second per square metre duct surface area
Vgt
o ltgt 0 ltgt N
ltgt Cgt
0 0 cc
0 0
~
g =
g ~
c 0
J
ltgt 0 I
~ ] tn
ltgt ltgt
In ol
~ 0 ~ 8 ~
~
c ltgt ltgt
~ CJ
~ ~ ~ ~ 8
0shyij
~ ~ ~ t
ltgt ltgt 00
l
~
~ Q
c C
~ rshy
e ltgt
I 1
I Cgt ltgtv
c Co ~
~~ ~ 10
I
0 Cgt
fJshyq 410 ) 1 ltgt
ltgt N
~ shy ltgt ltgt
~ I 1
c
52
DW154 Specificatio for Plastics Ductwork
Example of a completed test sheet Test No
General
Name of job N~ jC43Pt(r2lef Building Repound ~(~~0
Part 1 - Physical details
a Section of duct work to be tested ~(diffPIfff~el1f3rd Floor
b Drawing Number g91~~ c ssure aSSJ L atlOn V~Jl~IRfYgtg~~lPre Cl T Class C
d Test static pressure -(9 raErq~ ~~~~-~~J~~~ ~~ ~~~~ll
Leakaoe factor 9~-tre3$ecMz I OM REFTOTABLE 13)e b bullbullbullbullbullbullbull
f Surface area of duct under test Q~tJJItetre$ CPROMCALCU TIO BELOW)bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull ampampamp bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull
g ]Vlaxi mum permitted leakage -~ (~i~~0 ~~r~~ ~~~l-~-11~ ~~~Q
Part 2 - Test particulars
a Duct static pressure reading 9QFt~q~ ~ middot~~~1 ~~
b Manufacturer and type of liow measuring d vice (-~~~cJ~Y-9Q7EYg c Range of measurement of now measuring device QtP)OQ~(e~~~0I~~~~1~I~ ~~~~~~W~
d Reading of flm measurin o device pmiddot IFROM RIO)ftscag ~
I (DERlVED [ROM CHART SUPPUED WITH RIG US 0 ud)1e Interpreted air flow leakage rate ~(~~~f~~~ (~l~~~~~~~~~~~~~~~~~I
f Duration ~~~~~norn~allY l~ lnil1Ut~~d~~~ it1~ W~ Date of test ~(lITled ut by Wltll s ed by ~ ~
(~lJ MIJLrr) (Si~rrfltJUYJ
Printed Name 1~g0f~ Printed Name ~~Y~9~ and Company 7jl~~~~~( UJd CompanY AB COII$Itallt8
Width and depth or diameter
Periphery ength Area
millimetreS millimetres metre qL1are metre
800 x 750 3100 1755 5440
600 x 650 2500 557 1193
300 x 300 1200 120 144
305 din 958 700 670
250 dia 785 450 353
TOTAL 8000
53
DW154 Specijilarion for Plastics Ductwork
pA XB
Guida ce No es For he ransport Handling and
Storage of uctwork
avoid damage to adjacent duct panels In somc ca es particularly on con acts calling f r repetitive sizes the use of timber jigs and spacers may be justified Where reduced bulk and greater protection are major factor such as consignments for export transporting ductwork in L shape sections may justify the increa ed ite as embly co ts
It is recommended that before a contract is finalised that consideration is given to the subject of site acces material handling and storage as tbcy havgt a strong influence on the cost efficiency of the overall activity of ductwOlk installation
B3 Handling To minilnise th risk of damage duct sections should be clearly identified and deliveries to site should be closely linked to the installation programme so as to avoid accumulation of
B1 Storage and Handling of Ra Material Material should be stored in suitably designed racking out of direct unJight Where possible the e racks should be metal to earth Edges of cut she t may be harp and protective gloves are advised Wearing teel toe-capped boots is recommended Most pIa tic sheet is manufactured with smootb mfaces andor is suppLied with protective coating Care must be taken to prevent accidental lippag of stacked materials Beiuoshy good electrical insulators the movement of stock unless earthed will allow the build up of stati All stock shapes are chemically stable at normal temperature Whil t some raw materials used in their manufacture may themselves pre ent a toxic hazard once incorporated into the lOck bape they no long r constitute such a hazard and no dermatitic bazard are known nor are any
unfiJied ductwork and minimise double handling It is important to recognise that ductwork panels joint and corners arc susceptible to damage and care must be taken wheu band ling such material through a site During handling individual item of duct work may be liable to light cross sectional deformation until thev become an integral pan of a completed ductwork system Whilst this may temporarily detract from its intended appearance thi deformation will not have any detrimental effect on the functionality of the finally a semblecl system Installation of duct work and asociated plant items ill illevitably involve manual handUng The responsibi Iiry of employers and employees to a ses the risk of personal injury during mallual handling operations is et out in the HS E publication L23 Guidance on Manual Handling Regulations 1992
environmental problems expected 84 Site storage
B2 fransport Large capacity vehicles with high-sided open or closed-top bodies are tlle mo t suitable for the transport of dllctwork Careful consideration should be given to the
Adequate floor space IDust be provided within tbe building for the site storage of ductvork Such storage shalt make due allowance for thc stOf(ne of ductwork in stacks such that access ~ egt
between them is of sufficient width to pennil the removal of item without interference to
unloading of transport on sit a not all siJes b n fit from the material handlino- and access facilities that exi [ in a manufacturing workshop such as crane- fork-lifts or loading bay Site handJiog facilities along with
adjoining sta ks Ductvork components should be positioned so a to avoid crushing Ductwork of small panel size may be stored horizontally however care should be exercised to ensure that tack sizes are limited 10 within
ehicular acce s restrictions may itilluence the type and ize of transport to be uWised
engtlls of ductwork should be positioned 0
the tmctural strength of the duct sections to prevent distortion of the lower sections within the stack
as to avoid crushing Lengths Witll projections such as branches and bends i1anges girths damper quadrauL should be loaded so as to
54
DW154 S1tciic(ltioll for Plastics Ductwork
85 Internal cleanliness of new ductwork The site storage of ductwork introduces the important cODsideration of maintaining the internal cleanliness of the ductwork R feren e should be made to HVCA documentshybull DWffM2 Guide to Good Practice - internal
Cleanliness of New Ductwork Installations If the above conditioDs can not be satisfied consideration should be given by tJle designer to amending the specification to include for Po t Installation Cleaning as covered by tJ1C HVCA documentshybull TRJ17 Guide to Good Practic - Cleanliness
of Ventilation Systems
APPE DIXC
Fi e Retardant inishes C1 Improvement in the fire retardancy of plastic
ducts can be achieved to varying degrees and is wholly dependent llPOll the surface coating laminating resin selected and construction specification adopted In some instances smoke emission is coILSidered equaUy with other speci fication requirernen ts of the materials resistance to ignition and bumjng It is therefore important for design rs to establ ish the clients and officers detailed requirements and not rely on a tbird party interpretation of fire resisting or fire retardant Where possible the specification should refer dir etly to compliance with a British or European Standard identifying the specific sections applicable There are various types of resin and mat rcLnforcements that can achieve a Class 1 surface spread of flame ratin o when tested according to BS476 Part 7 (1987) This test puts materials illto Class I - 4 in descending order of perfoDllance according to the rat and extent of flame spread over their surfac under standard beating conditions Materials should also be tested for flre propagarion to BS476 Part 6 (1989) Tbi tesr measures the amount and rate of heat evolved by the material when subjected to standard heating
conditions Test results are given as an index of Perfonnance (i) whicb is based on three sub indices (iJ (i1) (h) The higher the value of the Index of Performance (i) the greater is the material s contribution to fire growth The higher the value of the sub-index 0) rhe greater the ease of ignition aod flame spread The highest product performance classification as defined in Approved Document B of the Building Regulations is Class O This is acLlieved if a material surface of a composite ploduct i~ either a) composed throughout of materials of
limited combustibility or b) a Class I material which has a tlre
propagation index (i) of not more than 12 and sub-index (i l ) of nor more than 6
01 J Class 0 is not a cla$sif1cation identified in any British Standard test
There are resin system reported to be classified to Class O when tested to BS476 Pcl1S 6 and 7 however designers need to ensure that such sysrems can be applied to their proposed design In propriety resinmat system available the fabrication techniques and COITect application are critical to the integrity of the reinforcing and clas ificatiol1 For example in some systems the u e of a non-fire retardant gelcont on a fire retardant substrate would reduce the classification For further information see HVCA publication DW144 Appendix D
55
DW154 SplCijiClIliol1 for Plastics Ductwork
x Guidance otes For nspectmiddoton Servicing a d
Clean-ng Access Openings
D1 GE ERAL This appendix highlight in ummary fOI111
the acce considerations that hould be made by the design r iD terms of inspection servicing and cleaning Having considered the seop and the design of the dUCI work system relative to the guidelines outlined below the designer should clearly indicate which levels of acces should be incorporated into the manufacture of a new duct work system (See Table 14 and Note I b low it
D2 DESIGN CONSIDERATIONS
D21 In ptction and servicing requireshyments are set out in Section 15 of Lhis specification
D22 Cleaning requirements are set out in the HVCA pubUcation TRl7 Guide to Good Practice Clean Lines of Ventilation Systems and the guide tates The precise location ize and
type of access would be dependent on the type of ductwork cleaning inspection and te ting metbods to b adopted Care protection and standards of cleanliness prior LO cOlllmisionin o
are set out in th AV A publication DWITM2 Guide to Good Practice Internal Cleanliness of New Ductwork Installations and th guide state Wh re specific limits of cleanliness are required ductwork sball be cleaned after installation by a spcialist cleaning contractor It will b in the interests of tht desioner botb financially and practically to cunsider employing a specialist c1eauing contractor at tbe
outset of a contract to internally clean newly installed ductwork prior to bandover This approach would reali e the following benefit shyi) Tb actual numb r of cleaning
access panels could be detennined to suit the method of cleaning to be adopted (This may be 1 s than the maximum requiremen listed under Lev 13 of Table 14)
ii) Clear directions could b given to the ductwork contractor as to tJle size and location of cleaning access panels that are required to be fitted during the mauushyfaclunng pro s
iii) The specialist cleaning operation prior to commi ioning vould enable the cleaning contractor to verify the practical acee requirement for the future cleaning operation associated -vitb a regular maintenance programme
iv) A specialist cleaning operation prior to commissioning would allow the designer to omit from the speeilicatiolJ the DWrrM2 requirem nt for factory sealing protection wipe downs and capping-off
v) Specialist Ieall ill 0 to the measurable standard defin d in TR17 will allow an objective definition of cleanline to be achieved
Car ful consideration must be gIven by the designer to the practl aJ problems associated witb the manufacture and fitting of suitably si Led access panel on small cross section duct and on the circular faces of rouod and flat oval ducts in particular
D23 Special con ideration must be given by the de igner to the practical problems associated with gaining personnel access to heavily congested ceiling areas and multi-la red du twork systems This approach would avoid
56
DW154 Spfciication for Plastics Ductwork
the possibility of access panels being D3 ACCESS 0 IN-LINE EQUIPMENT incorporated into a ductwork system at the This appendix unly covers acc il1spection manufacturing stage that were later found in through the ductwork body adjacent to an item practice to be inaccessible for either ervicing of in-line equipment and not openings in the or cleaning activities equipment itself
able 14 Acce requirements for inspection servicing and cleaning
HVCA PUBLICATIO REFE NeE (uidtgt 10 Gund Prartict
Adjace t OW144 Cleanliness orVcnlillltio S~lcr~ fRjJ7
in-line LeyeJ 1 Level 2 Level 3 ite sequipment pcdionSen lcin~ Section d C1eaniJl( SUn(O)lnspc lion Palle ltk~m_n
2011 (minimum OiL Jubje-ct to duct ~zel (ft~ -Panels
Control Da pcrs One (inspection) 203 One 300 mm x 200 mm Both sid Fire Dampers One (sCTjdJl~) 20211 One 300 0101 x 200 mm One side HeatingCooling Coils One (inspedion) 20213 One 300 mm x 200 mm (lIpstream) Both sides Attenuators (rectangular) None required One 300 mm x 200 mm (downstream) Both sides Attenuators (circular) one retluired One 300 mm x 200 mm (downstream) One side Filter Sections One (inspection) 20212 one required Uoth sides Air Turn Vanes None requjred None required Both sides Changes of Direction None required one required One side In-Duct FansDevices One (inspection) 20213 None required Both sides l
1 In the absence of any indication by the designer only Level ) access will be jncorporated into a new ductwork system
2 Tbe panel izes associated with Lev lis I and 3 acee s ar e middottablished by reference to Section 20 of DW144 and Section 2 ofTRll7 respectively
57
DW154 Speclfifatio for Plastics Ductwork
pA XE
B-bliography Included in this Bibliography are technical pUblications which may be of interest (0 ductwork designers fabricators and erectors and to tho e in the heating ventilatlng air conditioning industries generally nquiric should be made of the relevant organisation at the address quoted Since its publication other addresse contained within 0V154 mav have changed and some pubJicalions may have been superseded
HEATING AND VENTILATING CONTRACTORS ASSOCIATION
4 Palace Court London W2 4JG Telephone 020-7229 2488 Fax 020-7727 9268
Orders fo FlY A Publications Old Matlsion House Eamont Bridge Penrith Cumbria CA 10 2BX (Telephone 01768 864771 Fax 01768 86718) Email hvcapoblicationshvwelfarecouk DWn 44 pe ilicatiun for sheet mctal duclwork (Iow- mediulllshy
and high-pressure) 1998) DWIl4 A practical guide to dUGI ork I akage te ting
(revised 2000) DWII54 Specification for plastic~ duct rk DW171 Guide to good Practice for kitchen venlibtion system DW191 Guide to good pracuce glass fibre ductwoJk DwrrMI Acceptance cheme for new products - Redangolar cro
joint classification Guide to good pra tice - Internal cleanliness of new ductwork installations Guide to good practice for the design for the Installation of lire and smoke uampers
J 1Other puhlications
HampV safely guide 5th edition JS2 Tool box talks JS5 Weldlng Safety booklet JSI9 afety facts bo klet Fact sheets 1-24 2nd edition JS2J COSHH manual volume 1 Advice on compliance with the
regulations 1521A CO I-rH manual volume 2 Asses mcnt h ets JS23 Ri k management manual TR3 BrazinltT and bronze welding of copper pipework cUld sheet
(I 976) TR5 Welding of carbon steel pipework (1980)
TR6 Guide to Good Practice for Site Pre sure Testing of Pipework (19 0) Guide to good practice cleanliness of ventilation Ylem
CHARTERED IN TITUTlO OF BUILDING SERVICES E G EERS Delta House 222 Balham High Road London SW12 9BS rTelephone 020-8675 5211 Fax 020-8675 5449) CIBSE Guide Volume A Design Data Volume B In tallatiol1 and quipment Data Volume C Reference Data
CommlssioniJIg Codes These Codes eover the preliminary checkS eUing to work and regulation of vanous catcgories 0 plan The Codes give a guide to design implications Series A Air Distnbution Systems Series B Boiler Plant
ri s C Automatic Conlrol ystems Cr1es R Refrigerating Sy terns
Sene iN Water Distribution Systems
Technkal Memonllda TM 4 Design Notes for the Middle East TM bull Design otes for Ductwork TM 13 Minimi iog lhc Risk of egiounaires Disease
Research Reports RROI95 Ventilation system hygiene - A review of published
infomlatioo on lhe occurrence and ffects of Olltamination Rl~02J95 Air-to-air heal rec v ry RR0395 rnfluen e of HV C on smoke detectors
ATlONAL ENI [ERING SPECIFICATION LfMITED Southgatc hamber 3739 Southgate Street Winchester S023 9EH (Telephone 01962 842058 Fax 01962 R(8982) BUfLDING S RVICES RESEARCH AND [ ORMATION ASSOCIATIO Old Bracknell Lane West Bracknell Berkshire RG 12 4AH (Telephone Brackl1eU (01344) 426511 Fax 01344 487 -7 )
Application Guides AGln4 De tglJing Vana~le Volume middotylans for KOOnl
iir Movement AG1I91 Commissioning of V Sylcms in Buildings 11 6194 Fire Dampers
B) 94 cntiJalion or KitcneTls
AG389 The Commls ionin of Air Systems In Buildmgs AH2192 Commissioning of Bern - A ~ode of Practice TN2417 I Fire Dampec il) Ventilating Ducl
BEATING VENTILATING A AIR CONDITION G MA UFACTURERS ASSOCIATIO (HEVAC) HEVAC Henley Road Medmenham Marlow Buck SU 2ER (Telephone 01491 578674 ox 01491 575024 Emoimiddot infofetacouk)
Publicatjons Air Diffusion Guide Guide to Air Handling Unit Leakage Testing Guide to Good Practice Air Handling Unit Real Room Acoustic ~ st Procedure Specification for the ertiiicatioll ofAir Filters Method of Test for Water Rejection PerfOnTlatce of Louvrcs Subjected 1(1
Simulated Rainfall Test Procedure for Acoustic Loo cs Specification 10 Floor GrilJes - Types Performan e and Method ofTest Specification for the Determination of the Collection Efficiency of SilJ1d
Trap Louvre Domestic Mechwlical Vclltllalion Systems with Heal Recovery Fan Application Guid
~an and Ouctwork Installation Guide Guide to Fan Noise and Vibration
pecification of Requirements for JallJral Smoke and Heal Exhausl Ventilators
pecification for Powered Smoke and Heat Exhaust Ventilators
Specification of Requirements for Smoke Curtains Design Gujue of Smoke Ventilation for Single Storey Lodustrilll Building~
Including those with Mezzanine Floor and IIi Racked Storage Warehou es - Issue 3
Guidance for the Design of Smoke entilation YSlem for Covered and Undergrollnd Car Parks - lssue 1
Application of SOloke Control Equipment and Syst m Guid to Good Practice - Isue J
58
DW154 Sp(C~tiifitiol for Plastics Ductwork
BRITISH STANDARDS INSTIT TION Sales Department 101 P ntooviLle Road London NI 9ND (felephone 020-78 1 78801)
CP 413 1973 Ducts for building ervices
SS 476 Fire tes on building matenals and lruc(ure
Part 4 19 4 Non-combustibility lest or materials
Part 6 I Fire propagation lest for materials
Part 7 1993 Surface spread of tlarnJ tesls for materia
Part 20 1987 Fir resistance of elements of construction
Part 21 1987 Fire r sistlUlce of loadbeanng elements of construction
Part 22 1987 Fhe istallceofllon-loadbearing elemcllts ofconsttuclion Part 23 1987 Contribution of componcnts to the fire resistance 0 a
structure
Part 24t987 Fire resi lance of wl1lilation ductl
SS 5588 nan 919 0 Fire Precautions III thc desIgn and OOSlnJ lion of buildings
S 729 1971 Hot dip galvanized oatiugs (or irOIl aod stcel articles
BS 1449 Steel plate sheet and Irip
Pan 11991 Carbon steel plate heel and strip Part 2 1983 Stainless steel plate sheer and strip
and
B middotENJOI49-2 996 BSEN 10149- 1991)
BSEN 10131 1992
BSEN22063 Sprayed metal coarings 1994 Protection of iron and steel by aluminium and zinc against
atmospheric cOlosion Irotectiotl of iron and ste I against corro ion and oxishydation at elevared temperatures
BS 353 1981 Glossary of lerms relnting to thermal insulation
BS ISO 1479 Self-tapplngscrewsandmetallicdri c crew
B -lSO 7049
1994
B 4800 1989 Painl colour for building purposes B 4848 l0 rolled structural steel sections
Part4 1972 Equal and unequal angles BS 5422 1990 Specification for the use of therm illuating matcriulS
SS 5720 1979 ode of practice for mechanical veutilating and air C 11shy
dirionin bull in building
l3S PR 12814-1 Bend resting for plasric welds
SS PR 12814-2 Tensile testing for plastic welds
SS PR 13067 Appro altesting for plastic welds
BS PR EN I 100-] Vi ual in pection ofplaslic welds
SHEET METAL AND AIR CONDITIONING CONTR-CTORS NATIONAL ASSOCIATION INC (SMACNA) Headquarters 420 I Lafayeue Center Drive Chanlilly Virginia 2051-1209
Mailing Address pa Box 221230 Cbantilly Virginilt120 153-1230
Telephone (703) 803-2980 Fax (703) 803-3732
Accepted IJJdustry Pl3Gtice for Industrial Duct Constnlelion 197 ) i-rchitecmral Sheet kwl Manual ([993)
Comractors Guide lor Modification 10 ooslruerion Colllraets 1993 Ducted Eleclric Heat Guide for ir Handling Ssrerns (1994)
En~rgy ollservatioD Guidelines (1984) Energy Recovery Equipment yslClllS (199l
Fibrou GIns Duct onS1ntClion Standards (1992)
Fire Smoke amp Radiation Damper In tall Guide for HVA Syst ms (1992) Guide t leel Stack 1(95)
HVA Air Duct Leakage Test Manual (19 ) HVA COlllmissioning lvlanual (1994)
H A Duct Construction Standards-Metal amp Flexible (1995) Addendum 01 (Nov 1997)
HVA Duct Systems Inspection Guide (1989)
HVA ySlems-Application (1986) nVAC ByternS-DLlct D ign (1990)
HVi Systems-Testing Adjusting amp Balancing (1993)
indoor Air Quality Manual (1993) tcheu quipment Fabrication Guidelmes (1990)
Managers Guide for elding (1993)
Rectangular Industrial Duct Cons1TUction Standards (19 0) Round Industrial Duct oustmction Standards (1977)
Sei mic Restraint Manual (1991) (wl Appendix E 1993) SMACNA Ma le Index ()fTechnical Publications (1995) Tbennoplnstic Duct CPY ) Construction Manual 1994)
DEPARTME OF THE ENVIRO MENT (Publications Centre) H Stationery Oflice 5 Nine Elms Lane London SWS 5DR
MampEJ 011972 Electrical in tallat1011 in buildings ( ew Editiou)
IampE 0319 Healing hot and cold wat r steam and gas losla1lations for buildings
M amp - No4 1970 Central heating and hot and cold ~ ateT in tallations for
dwelling
M amp ENo100 1971 Mechanical ventilation for building~
ASSOCIATION FOR SPECIALIST FIRE PROTECTlO As ociation House 235 Ash Road AJdershot Hampshire GUl2 4DD
Telephone OJ25221322 Fax 0 J252 333901
lublicalioos Fire Ratcd and moke Outlet Ducrwork An Industry Guide t Design and InSlalla lioll
HEALTH AND SAFETY EXEC TIVE Rose Court 2 Southwark Bridge London SEl 9HS Telephone 020-7717 6000
TWJ THE WELD G TlTUTE Abington Hall Abington Cambridge CB16AL Telepbone 0 J223 89162
Publication DatJ Oil w~ldll1g of lhermopla lics
59
DW154 wciiwlioll for Plastics Ductwork
A -=--DIX
Factors
Specific gravity shy pp = 091 approx UPVC = 14 approx
Some miscellaneous conversion factors
To convert
Length Inches to millimetres Feet to metres
Multiply by
2540 03048
To convert
Millimetres to inches Metres to feet
vIultiply by
003937 3281
Area Square inches to square millimetres 6452 Square millimetres to square inches 000155 Square feet to square metres 00929 Square metres to square feet 10764
Volume Cubic feet to cubic metres Cubic feet to litres Gallons (UK) to litres
002832 2831 4546
Cubic metres to cubic feet Litres to cubic feet Litres to gallons (UK)
35315 00353
022
Mass Ounces to grams Pounds to kiJograms Tons to tonnes
2835 04536
1016
Grams to ounces Kilograms to pounds Tonnes to tons
003527 2205
09842
Volume flow Cubic feet per minute to cubic Cubic metres per second to cubic
metres per second 0000472 feet per minute 2119 Cubic feet per mIDute to litres Litres per second to cubic feet
per second 04719 per minute 2119
Motion Feet per minute to metres per second 000508 Metres per second to feet per minute 197
Pressure Inches water gauge to millibars 2491 Inches wateJ- gauge to pascals (Pa) 2491 I Pa = I ewton per square metre = 10-2 millibars
60
Heating and Ventilating Contractors Association Esca House 34 Palace Court London W2 4JG
Tel 020 7313 4900
e-mail contact Itvcaorguk web site wwwhvcaorguk
Fax 020 7727 9268
DW154 Spcification for Plastics Ductwork
2424 Workshop conditions Polyester resuls are sensItIve to lmperature and the workshop hould b maintained at a temperature of herween 20deg and 25degC HiOh relative humidities and damp onditions should be avoided A good rate of air change must be pro icled pJeferably by m chanical ventilation
2425 Storage of materials Resin and urin o agents shouJd be stored in dark cool condirions away from the working area and in confonnit with statutor requireshyments for tJle middottorage of flarmnable liquid Because of Ule Limited torage lif of the unmixed resin and curing a eot mal lials ~hould be ch eked before use to enLlfe that they are within the manufacturer pe ified sh If life (usually ix month from the dm of manufacrure)
Glass fi re should be stored separately und r clean dry conditions
243 Surface preparafon
2431 UPVC To achieve the specified bond strengtll the urface to which the GRP is applied mut first be thoroughly cleaned and then etched either by mechanical means or by the use of a suitable solvent
2432 pp with glass fabric backing To achieve the specified bond middottrength the fabric backing must be thoroughly impregnated Witll resin
244 Mixing the materials for use The re in 1 a three part mix compri lng base I sin hardener and accelerator The manufactur rs pecj[ied proportions are critical and th llUxmg sequenc pecified must be meticulously foUowed
The resin has a very limited life after mixing and before u e It is dependent on the characteri tics and bulk of th resin the alllount of hardener the degree and method of acceleration and the workshop onditions
245 Methods of application
2451 General The mixed resin may be applied by hand or b pray c1epoition The operation must b completed within the gel time of th y tern and tbe laminat fully cOI1olidated to achi v the phy ieal properties pecified
2452 Hand lay-up The duct surface i coated by hand with resin Llsing a brush and a mar of gla fibp orked in until full consolidation achieved Th proc is repeated untiJ th requird thicknes i obtained
2453 Spray depo Won The duct surface is coated WiUl re in by spray gun with the chopped glass roving added through a separate nozzle The full thickne i obtain d in layer with con olidation of each layer by hand roller
246 Construction
2461 General M ini mum COllst ructional requireshyments are pe itied ill Tabl 10 for rectangular and Table 1J for circular dUClS
2462 Joints and stiffeners Fig 29 30 31 32 amp 33 hoI TOSS
joint and tiffener for reinforced UPVC and PBPP duct
247 Worki g practices The fabrication of ductwork pecifiecl ill thi document i not affected by the addition of GRP
29
DW154 SfJcdJicatiOt for Plastics Ductwork
Table 10 Minimum constructional requirements shy
Longer Side Minimum Sheet Thicknes and
GRP Reinforcement
UPVC FBIPP 1 2 3
mm mm mm Up to 1000 3 plus 3 plus
06 kgm2 06 kgOIl GRP GRP
1001 to 2250 45 plus 3 plus 06 kgm 12 kgm
GRP GRP
2251 to 3000 45 plus 6 plus 12 kgm 12 kgm
GRP GRP
Cross Joints
UPVCFBPP 4
mm socket amp spigot
as Fig 30 or flanged as Fig 29
75 x 9 flange welded on both sides as Fig 29
75 x 9 tlange welded on both sides as Fig 29
rectangular GRP reinforced ducts
SlifTeners Maximum Spacing Between
JointsSljffeners UPVCIFBIPP UPVCFBPP
5 6 mm mm
75 x 9 flat 800 as Fig 31 or
50 x 50 x 5 plastic or MS inverted angle as Fig 32
or tormer as Fig 33
75 x 9 flat 600 as Fig 31 or
50 x 50 x 5 plastic or MS inverted angle as Fig 32
or former as Fig 33
75 x 9 flat 600+shyas Fig 31 or 50 x 50 x 5 plastic
or MS inverted angle as Fig 32
or former as Fig 33
Note 1 On rectangular duct up to 400 mm longer side no stiffeners are required 2 Applies to Tables 10 amp I I For COlJstructional operating temperature limits refer to Part 2 clause 5A 3 Tables 10 amp II apply to all pres ure classes up lo ]500 Pa
Table 11
Diameter
1 III
lJp to 1000
1001 to 1750
1751 to 2500
Minimum Sheet Thickness and
GRP Reinforcement
UPVC FBPP 2 3
mm mm 3 plus 3 plus
06 kgm 06 kgm GRP GRP
45 plus 3 plus 06 kgm2 18 kgm
GRP GRP
6 plus 6 plus 12 kglm2 18 kgm1
GRP GRP
Cross Joints
UPVCFBPP 4 III
socket amp spigot as Fig 30 or flaoged as Fig 29
75 x 9 flange welded on both sides as Fig 29
75 x 9 flange welded 00
both sides as Fi 29
inforced ducts
Maximum Spacing Between
JointsStiffeners UPVCIFBPP
6 mm 2400
800
600
Stiffencrs
UPVCFBPP 5
mm 50 x 9 flat as Fig 31
75 x 9 flat as Fig 31 or former as Fig 33 75 x 9 tlat as Fig 31 or t()rmer as Fi 33
ote On extruded tube tip to 600mm diameter no stiffenergt are required
30
DW154 Specificatioll for Plastics Ductwork
G - Cross joints and tiffeners
Fig 29 Flange Joint Fig32 Stiffener shy inverted angle
M artiPfCuQkbdd erttpObri) Wl111 RP tlddtlt
_- GRPloliu] lh~
Fig 30 Socket and spigot joint Fig33 Stiffener shy use of former
Fig 31 Stiffener Flat
I Pv FlPP ~ ~lmJaDUA1) d
OMrlQ rrnall 1( tQlS
25 STANDARD COMPONENT DRAWINGS AND ABBREVIATIONS
251 The illustrations in this section not only highlight where applicable geometric limjtations for the de ign and manufacture or ductwork components but also recommend
standard drawing representation terminology and abbreviations for both duetwork components and some of the more commonly used ancillaryplant items
252 Designers and surveyors should note that bills of quantities should provide a full description
3)
---
v
DW154 Spcc(fim(ml for Plastics Ductwork
Fig 34 Linear Thermal Expansion
u c 0 N ro 0)
b 0)
S
sect0
5 oS cl) 0)
~
on ~ ltl
c U
-30 -20 -10 0 10 20 30 40 50 60 70 80 90 TEMPRATURE C
~ V
-
~~c_ ~
~V
V ~
-7 ~
-- ~V ----
v
-6
+14
+12
+10
+8
+6
+4
+2
0
-2
--4
ig 35 Typical Design Stress tor UPVC and P
7
6
r shy 5E
-c E----0 4t) VJ 0)
ci5 0Jl 3
~
0)
Cl
2
1
o
UPVC
1
000
1
1
pp
- r-- shy r----- shy - t--shy I
__0
-30 -20 -10 0 10 20 30 40 50 60 70 80 90 TEMPERATURE C C
Note Figso 14 amp 35 shaded area refers to GRP reinforced duct
32
DW154 Speciicfltirm for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - REC ~NGULAR
Splilt~r Posilion W-mm pliucr
A B c 40]--QOO 1 W - -
601-1000 1 W4 Wf2 -
1001-1800 3 WI W3 W2
FIG DRAWING DETAfiS
tU]36 ATI Straight Duct with socket and spigol joint
rn [037 Straight Duct with flanged joints
[I []38 Straight Duct with flanged joints
rkJ Short Radius Bend
39 Applies to any augl and for duct up to 400 n11n wide
Minimum (I1m31 radills = 100 mm
Medium Radius Bend (a illustrated)
[kJ Applies to any angle
40 Long Radiu Bend Similar but radius = W
Throlll radius = W2 Applies to any angle
- Short Radius Bend with plitlers
I -shy -shy u co - t lt Li--_ 41 t 0 ~ I I I
~ I
L 1W
Minimum waal radius = 100 mm Splitters not required in bend angle less than 45deg
42 QJ1 Square Bend with turning vanes ij
3
DW154 SP(L~ficatioll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - RECTANGULAR
FIG DRAWl G DETADS
43
~
I v
L L Radius Tee with internal deflectors
44
~ Radiussed Twin Bend
45
Imiddot
er Swept Branch
46 U-
Sqoare Tee with Turning Vanes
47
~ f
Breeches Piece
48 0 y l Piece
34
DW154 Specificatioll for Plastics Ductwork
STANDARD COMPONENT RAWINGS - ECTANGULAR
55
54
51
50
53
52
49
FIG
~MX
RAWlNG
DmiddotMAX
EfjMAX
Minimum throat rndius = 100 mm
Rectangular shy Round Transformatioll
Eccentric Taper 225deg max in either plane Spliller are required for angles greater than 225deg and hould bi eet the angle between any side and duct centreline
DETATLS
Angled Offset
OUset Taper Splitters are required for angle greater than 22 0
and shoold bi eet the angl between any side and dUCI centrelinc
Mitred Offset
Concentrk Taper 2250 max in ither plane SpUtters are required for angle greater than 225deg and should bisect the angle between any side and duel c ntreline
Radiussed Offset
35
DW154 Splcilcuthm for Plastics Ductwork
STANDARD COMPONENT DRAWINGS ~ RECTANGU AR
Branch ducl DimCllsions widlh (W) (A)
urnl mm up lO 200 75
300 100 400 125 600 150
Ocr 600 200
FIG DRAWlNG DETAILS
56 poundplusmni~~ Rectan~lar - Flat Oval Transformation
57 [ Square Branch
58 er Angled Branch
Branch dUCI Dimensions wfdth (W) (A)
[- mm mm59 3shy Shoe Branch Up (0 200 75
--shy AIshy + 300 100
400 125
450 MAX 600 150
Over 600 200
Branch duct DimensIOn
rP X width (W) A)
60 - 1--shy _
~ mm mm
Bell Mouth Branch pto 200 75 300 100 t 400 125
600 150 Over 600 200
0=0 61 -
~ Bell Mouth
- shy T 4-5deg M x
--I 1-shy
TJ
62 X I ] I
Tele-scopic Joint I Illustrated with flangeL
X63
SBD Single Bladed Damper
36
---
DW154 Spedicatioll for Plastics Ductwork
STANDARD OMPONENT DRAWINGS - RECTANGULAR
DRAWING DETAILSFIG
64 on-Return DamperNRD shyshy
shyXbull
Multi-Leaf Damper Can be piggoted or flanged oppo cd or parallel blade
Alternative controls areshy
q p [gtshy
J HD65 Hand
~MD otori ed
PO Pneumalic
L-lt
l 13G 66 Blast Gate DamperX X
FireSmoke DampersSleeves
211r Ratinggtshy----
L_-
---
----
r----
Ir-- shy
IL- _-l
2hr
With i tallation frame
67 41 r Rating
4hr
Smoke damper SD
Intumc cent Sleeve L-d
37
DW154 Specijicutiolt for Plastics Ductwork
FIG
68
69
70
71
STANDARD COMPONET DRAWINGS shy REC ANGULAR
DRAVING DETAILS
gtshy Access Openings
AP 6 Access Panel - Rerno able
w [ ~ Access Door - Hinged
I ~le Inspection Cover
le -I reg -lt
~X X Flexible Connection
~ Drop Cheeked Radiussed Twin Bend
U Drop Cheek Bend
I
72 Air Flow SymbolX
38
DW154 Specifim[ioll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - ECTANGULAR
FIG DRAWING DETAILS
73
74
75
76
77
Q
Q
rp---t
~
V- I Ir---I
JL --11
THE ABOVE DETAILS TYPICAL PLENUM
Air Terminal Plenums
Plenum with side connection
Plenum with top connection
Cover plate with connection
Special plenum with connection
elescopic conn ction in direction of air flow
39
DW154 SpecijicotiOll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG
78
79
80
81
DRAWING
-23~---pound3-(MALE) (FEMAJE)
-t=j--_j(--d-shy
--L
~ THROAT RADI S= D AS T NDARD
e ~
THROAT Rjf)lU = D A MU)
DETAILS
Straight Duct With male and female connectors
Straight Duct With flange joint and slip joint
Bend MouldedIFormed Applies to any angle ego 30deg45deg60deg90deg Medium radius bend as illustrated Long radius similar but throat radius 0
Segmented Bend 90deg four section minjmum as illustrated
Other Angles 60deg = 3 sections 45deg = 3 sections 30deg = 2 sections
I
i
40 shy
DW154 Speciicafinll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG DRAWING DETAlLS
82 Segmented Twin Bend Radius = D2 max
May also be fabricated from tube
83 Equal Tee MouldedIFormed
84 -~ 1in Bend MouldedIFormed
85 Taper Concentric 1 0 as iUu trated Eccentric 30deg iJJcLuded angle
86 Short Taper
41
DW154 SpcUicatol1 for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG DRAWING DETAILS
87 30 max Offset
Angle Branch
Bran h dUCI Dimcnsions dia (D) lA)
Shoe Branch mm mm 88 Cl
Off rectanguJur Up 10 200 75 lOO 10 400 125
- 00 150 Over 600 200
Bl1IllCh duct DimenlOns din (D) (A
~-$a-Conical Branch mm mm
89 Also acceptable with Up 10 200 r
full conical surface 300 10
400 125
END VrE -shy 600 150 Over 600 200
90
m 75
100 12 150 200
mm Up to 200
_ 300 400
600 Over 600
iUtred Branch
Shoe Branch
J-L----U ~ Bell oulh Branch
ENDV1EW
93
92
91
42
DW154 Specificatiol for Plastics Ductwork
STANDARD OMPONENT DRAWINGS - CIRCULAR
FIG
94
DRAW G
I
~ 30deg 090deg
Breeches Piece
DETAILS
95 amp-----~ Blank End
~-----p Multi-Leaf Damper Can be piggolcd or fianged opposed or parallel blade
Alternative controls areshyri=-+- L-T~
I
---
LT~
I r- -
-+1
J HO Hand96
bMD Molori cd
PD Pneumatic
tl-shy bull
Single Bladed Damper 97 ~ saD
on-Return Damper Vertical application only 98 m~D
43
DW154 Sf1tcificatioll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG
99
100
101
102
DRAWING
$ I-
2hr
1 4hr
SD
~v I I
CO TINENTAL COWL
DETAILS
Iris Damper
Fi reS moke Dam persSleeves
2hr Ratillg
With installation frame
4br Rating
Smoke damper
Intumescent Sleeve
Access Openings
Access panel - removable
Access door shy hinged
fnspection cover
Discharge Continental Cowl
44
DW154 Sp(Cii(ltJll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
DRAWINGltIC DETAns
-
I
I
~
I I I High Velocity Discharge Terminal 103 I
I
I I
J I I 1 ~--
Offset Stack Discbarge Terminal 104 1
~ I e --(-
I
N
I
I
I~
I I Vertical Oischarge with Weather Cowl 105 I
--1--1 I
I
GAPI I
RTl AL DISC) lARGE WITH W ATIIER COWL
45
DW154 SpecUicatoll for Plastics Ductwork
STANDARD COMPONE T DRAWINGS - PLA TEQUIPMENTIMISCELLANEOU
FIG DRAWING DETAILS
106 ~~~ Rectangular Attenuator
107 ~- Circular Attenuator
108
~ Beod Attenuator
109 J ~(f) Heating Coil
110 J ftte Cooling Coil
III Jc[ Electric Heating Coil
112 X F
Humidifier
113 [H XX Axial Fan
114 ~fB1famp Noo-standard Ductwork Cross hntchillg (of any separate type) indicates by reference to a key any non DVil54 ductwork system
115 2llIIIIJIIIIIll Flexible Ductwork
46
DW154 SJeCUicll(iol1 for Plastics Ductwork
TABLE 12 - STANDARD ABBREVIAT ONS
ABBREVIATION FLL
AD Acces Door
AFF Axial Flow Fan
AHU Air Handling nit
All Aluminium
AP Acess Panel
AT Attenuator
AV Air enninal Unit
BE 81ank nd
BQ Blast ate Damper
CC Cooling Coil
CF Centrifugal Fan
CTA Cross alk Attenuator
CVU Constant Volume Unit
DP Drain Point
EEC Electric Heating Coil
El Expansion Joint
FAl Fresh Air Inlet
FA From Above
FB From Belo
fBPP Fabric Backed Polypropyl-ne Sheet
Flexle Flexible Connection
lexfD Flexible Du t
C False Ceiling CO an oil Unit
fD Fire Damper
FFL Finished Floor Level
FJ Flanged Joint
FOAM Rigid Polyurethane Self xtinguishing Foam
FOB Flat on Bottom
FOT Flat on Top
GAM Galvanised after ManufacttrJc
GRP Glass Reinforced Plastic
GSS Galvanised Sheet Steel
HC Heating oil
HD and controlled Damper
HH Hand Hole
HL High Level
HVD High Velocity Discharge
IC Inspection Cover
ID lri Damper
IFS Intumescent Fircleevc
47
DW154 Specification for Plastics Ductwork
TABLE 12 - STANDAR ABBREVIATION CONTINUED
ABBREVIATION
IU
L
tv1D
MS
NRD NTS
OBO
OE
PHD
PD
PP
PP
PRD
PVC
RFC
RSC
R
SBO
SO
S1 TST
SSL
TA
TB
TO TJ
TP
TV
TV
OS
UPVC
S
V
VAV
50 RSA
FULL
Induction Unit
Low Level
Motor controlled Damper
Mjld Steel
on Return Damper
at to cale
Opposed Blade Damper
Open End
Parallel Blade Damper
Pneumatic controlled Damper
Polypropylene
Self xtinguishing Polypropylene
Pressure Relief Damper
Polyvinyl Chloride
Rolled Form Chamlel
Rolled Steel Channel
R fUnit
Singl Blade Damper
Smoke Damper
Slip Joint
Stainl t el
tructural Slab Level
To Ab vc
To Blow
Top Down (In Direction of Flow)
Telescopic Joint
Test Point
TU111iog Vane
Top Up (In Direction of Flo )
Voles Otherwise Stated
Unpl3sticisecl Polyvinyl Chloride
Underside
Ultra Violet Light
Variable Air Volume
Rolled Steel Angle (Vith Size)
48
DW154 SJeriiflllioll for Plastics Ductwork
A2 DUCT PRESSUREAPPE DXA Ductwork con truct d to DWIl54 will bebullbullbullbullbullbullbullbullbullbullbullbullbullbull
Air Leakage From Ductwork To be read in conjunction with DW143 A practical guide to Ductwork Leakage Testing
CAUTION As highlighted ill both this docul1lenr and DW14 I lot ellough emphasis can be placed 01 the fact that except for high pressure class C the much more stringent ductwork constructional standard brolght about b the general acceptance of DW154 have irtlally negated the requirement for leakage-testing It is essential lO realise lhat except where it is mandatory this doclllllelll is nOl an endors ~lIlent of the rourine testing of ducts bllt purely a guide to outline the procedures for cononnity with the air leakage limits ill Table l Where the specified methods of assembly and
A3sealing of dlcls are u ed a vi ual inspection wil ordinarily sl~fll e for ver(iatioll of a well engineered and a ceptahfy airtight COl1strucrioll WHERE NOT MANDATORY DUCT LEAKAGE TESTING IS GENERALLY AN UNJUSTIFIED AND SUBSTANTIAL EXPENSE
A1 INTRODUCTION L akage from ducted air distribution systems is an Lmportant consideration in the design and operation of ventilatjon and air conditioning middotystems A ductviork t)ystem tbat ba limited air leakag within defiucd limits wiH cnsUft
that tile design characteristics of the sytem can be maintained It wilJ also ensure that energy and operatLonal cosb are maintained at optimum levels DucLwork constlucted and Ulstalled in accordance with DW154 should minimise a level of air leakage that it) appropriate to tll operating static air pre sur in tile system
A4However it is recouuised that tbe environment in wtJich middotystems are installed is not always conducive to achieving a predictable level of quality in term of system ajr leakage and it is therefore accepted that designer may sometimes require tlle ystem to be tested in part or in total It should be ecogni ed that the testing of duct systems add a ignificant cost to the installation and incur some extra tjm within the programme (Se 47 and 64 re mandatory te-sting)
manufactured to a structural standard that is compatible with the system operating pressure There are three classes of duct con truction to eorre pond with the three pre ure clas meations Class A Lo pressure ducts suita le for a maximum positive operating pressure of 500 Pascal and a maximum negative pressure of -500 Pascals Class B IVledium pressure ductmiddot suitable for a rnaxilnuJJl positive operafjn o pressure of 1000 Pascals and a maxllnum negative pre sure of -750 Pa cal Class C High pre sure ducts suitable for a maximum po ilive operating pressur of 2000 Pa cals and a maximum negativ pres ur of -750 Paltcals
LEAKAGE FROM DUCTWORK Leakao-e front pia tic air ducts occur at the joint~ and is therefore proportional to the total surface area orthe du twork in th system Tb level of leakage i imilarly related to tIle air pres ure in th du t system and whilst there LS n precis formula for calculating the level of air los it i generally accepted that leakage will increase in proportjon to pressure to rbe pOvver of 065 The effect of air leakage from high pressure velocit ductwork is critical tn terms of system perfomlan dege energy consumption and the risk of high frequency noise as ociated with leakage These problems are le critical with medium pressure 10 ity systems but should be con idered Low pres mevelocity ducts present the lowe~t
ri k in tenn of tbe effect of leakage on the operation of the s stern
SYSTEM LEAKAGE LOSS As there i no di ct relatLonship between th volume of air conv yed and the surface area f the ductwork sy tern required to match the building configuratmn it is difficult to express air leakage a a percentage of total air volume Similarly the operating pressure will vary throughollt lh 3 system and a leakage is related to pre me the calculations ar comple However it is generally ac epted tbat in typical good quaJjty systems the leakage from
49
DW154 Specificatioll for Plastics Ductwork
each class of duct llnd r operating condition will be io the region of CIa S A low pressure 6 Clas B medium pres un 3 Clas C high pressure 2
A5 SPECIFYING AIR LEAKAGE TESTING Re peeting both the co -t and programme implications a sociated with te ling du 1 for leakage the designer may for example indicate that a particular system is te ted as follow
a) High pressure ducts - all tested b) Medium pr ssure duets - 10 of the
ductwork shall be s eet d at random and tested
c) Low pre sure - unte ed In any case where a random te t i elected for medium pre sure ductmiddot the followin c1au~e is suggested for inclusion by the de ign r
The designer hall elect at random a maxirnwlI of 10 of the dUCl system to bt tested for air leakage The duct hall be tested af the pressure recommended in Table J3 for the assifi atiol for the ectiol1 of the ductwork that is to be tested The tests shall be carried Ollt as the work proceeds and prior to the application of thermal insulation In the event of test failure of the randomlY selected section the designer shall have The right to select two La1her e tiolls at random for resting Where succes ive failures are identified there shall be a Tight to require rhl COl11raCWr 10 apply remedial attention to the complete ductwork system Th contractor shall provide documented eviden e of the calculalions used to arrive (1
the allowable 10 I for the section to be tested and the client or his agent shall willess and sign the results of the test
able 13 Air leakage rates
Maximum leakage of duct work Static
prcssUft Low-pressure edium-prc-sure I Iigh-prebull me diJfercntial Class A Class B Class C
1 2 J 4 Pa Litres per second per quare metre of surface area 100 054 018 ZOO 084 028 300 110 037 400 132 044 500 153 051 600 058 019 700 064 021 800 069 023 900 075 025
1000 080 027 1100 1200 1300 1400 1500
029 030 032 033 035
1600 1700 1800 1900 2000
036 038 039 040 042
Note Recommend d mean test presures are highlighted iD bold type with the actual selection being left to tll test operator
50
DW154 Sfeeiieaioll for Plastics Ductwork
A9
A10
and air leakage classification for the y em under test
DESIGNERS CALCULATIONS The designer can middotaJculate with reasonable accuracy the predicted total loss from a ystem by
a) Calculating the operatin presure in each ection of the sy tern
b) Calculating the surface area of the ductwork in each correspondin pre lire s ction
c) Calulating the allowabl~ los at the operating pressure for each ection of the system (see table 13 for allowable leakage figures)
VARIABLE PRESSUR S IN SYSTEMS De igner can achieve significant co t saving by matchina operating pressures throughout the system to constmctional standard and appropriate air leakage testing eO the practice of specifying construction tandards for whole duct sy tems based on fan discharge pre sure may incur unnece sary costs on a project For example ome large sy terns ould well be classiC ed for I akage limits as follows
Plant room risers CJas C Main floor distriblltJou CIa B Low pre sure outlets Cla A
A6 SPECIAL CASES There may be ~itLlations on a project where circumstance dictate thal pecial consideration be given to containing air loss s eg a long mn of duclwork may incur a di -proportjonate level of air 10 s In ca es such as thi example the designer can specify an improved tandard of airtighmess ie 80 of alJo~able 10 s for la B Ju ts The designer sbould not specif a CIa C t sI at CIa s C pressure for a CIa s B ducl
A7 SUGG S ED RANGE OF TES ING
A8 TESTING OF PLANT ITEMS Items of inline pJant (eg Fig 106 to 115) will not normaUy be included in an air I akage test The dllctwork contractor may indud such itelllS in tbe te t jf rh quipm ot has a certificate of COnfOlnlity for Ihe pres ure clas
bull High pressure duct bull Medium pre sure ducts bull Low pre sur ducts bull Exposed extract syst ID bull Ceiling void extract
systems bull Secondary ducts from
VAV or fan coil units bull Flexjble duct bull Final connections and
branches to grille and diffusers
100 test See A5 Untested UDt sted
Untested
Untested Untested
Untested
SI
i
DW154 SJecijicafion for Plastics Ductwork
ig 116 Permitted leakage at various pressures
Leakage in litres per second per square metre duct surface area
Vgt
o ltgt 0 ltgt N
ltgt Cgt
0 0 cc
0 0
~
g =
g ~
c 0
J
ltgt 0 I
~ ] tn
ltgt ltgt
In ol
~ 0 ~ 8 ~
~
c ltgt ltgt
~ CJ
~ ~ ~ ~ 8
0shyij
~ ~ ~ t
ltgt ltgt 00
l
~
~ Q
c C
~ rshy
e ltgt
I 1
I Cgt ltgtv
c Co ~
~~ ~ 10
I
0 Cgt
fJshyq 410 ) 1 ltgt
ltgt N
~ shy ltgt ltgt
~ I 1
c
52
DW154 Specificatio for Plastics Ductwork
Example of a completed test sheet Test No
General
Name of job N~ jC43Pt(r2lef Building Repound ~(~~0
Part 1 - Physical details
a Section of duct work to be tested ~(diffPIfff~el1f3rd Floor
b Drawing Number g91~~ c ssure aSSJ L atlOn V~Jl~IRfYgtg~~lPre Cl T Class C
d Test static pressure -(9 raErq~ ~~~~-~~J~~~ ~~ ~~~~ll
Leakaoe factor 9~-tre3$ecMz I OM REFTOTABLE 13)e b bullbullbullbullbullbullbull
f Surface area of duct under test Q~tJJItetre$ CPROMCALCU TIO BELOW)bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull ampampamp bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull
g ]Vlaxi mum permitted leakage -~ (~i~~0 ~~r~~ ~~~l-~-11~ ~~~Q
Part 2 - Test particulars
a Duct static pressure reading 9QFt~q~ ~ middot~~~1 ~~
b Manufacturer and type of liow measuring d vice (-~~~cJ~Y-9Q7EYg c Range of measurement of now measuring device QtP)OQ~(e~~~0I~~~~1~I~ ~~~~~~W~
d Reading of flm measurin o device pmiddot IFROM RIO)ftscag ~
I (DERlVED [ROM CHART SUPPUED WITH RIG US 0 ud)1e Interpreted air flow leakage rate ~(~~~f~~~ (~l~~~~~~~~~~~~~~~~~I
f Duration ~~~~~norn~allY l~ lnil1Ut~~d~~~ it1~ W~ Date of test ~(lITled ut by Wltll s ed by ~ ~
(~lJ MIJLrr) (Si~rrfltJUYJ
Printed Name 1~g0f~ Printed Name ~~Y~9~ and Company 7jl~~~~~( UJd CompanY AB COII$Itallt8
Width and depth or diameter
Periphery ength Area
millimetreS millimetres metre qL1are metre
800 x 750 3100 1755 5440
600 x 650 2500 557 1193
300 x 300 1200 120 144
305 din 958 700 670
250 dia 785 450 353
TOTAL 8000
53
DW154 Specijilarion for Plastics Ductwork
pA XB
Guida ce No es For he ransport Handling and
Storage of uctwork
avoid damage to adjacent duct panels In somc ca es particularly on con acts calling f r repetitive sizes the use of timber jigs and spacers may be justified Where reduced bulk and greater protection are major factor such as consignments for export transporting ductwork in L shape sections may justify the increa ed ite as embly co ts
It is recommended that before a contract is finalised that consideration is given to the subject of site acces material handling and storage as tbcy havgt a strong influence on the cost efficiency of the overall activity of ductwOlk installation
B3 Handling To minilnise th risk of damage duct sections should be clearly identified and deliveries to site should be closely linked to the installation programme so as to avoid accumulation of
B1 Storage and Handling of Ra Material Material should be stored in suitably designed racking out of direct unJight Where possible the e racks should be metal to earth Edges of cut she t may be harp and protective gloves are advised Wearing teel toe-capped boots is recommended Most pIa tic sheet is manufactured with smootb mfaces andor is suppLied with protective coating Care must be taken to prevent accidental lippag of stacked materials Beiuoshy good electrical insulators the movement of stock unless earthed will allow the build up of stati All stock shapes are chemically stable at normal temperature Whil t some raw materials used in their manufacture may themselves pre ent a toxic hazard once incorporated into the lOck bape they no long r constitute such a hazard and no dermatitic bazard are known nor are any
unfiJied ductwork and minimise double handling It is important to recognise that ductwork panels joint and corners arc susceptible to damage and care must be taken wheu band ling such material through a site During handling individual item of duct work may be liable to light cross sectional deformation until thev become an integral pan of a completed ductwork system Whilst this may temporarily detract from its intended appearance thi deformation will not have any detrimental effect on the functionality of the finally a semblecl system Installation of duct work and asociated plant items ill illevitably involve manual handUng The responsibi Iiry of employers and employees to a ses the risk of personal injury during mallual handling operations is et out in the HS E publication L23 Guidance on Manual Handling Regulations 1992
environmental problems expected 84 Site storage
B2 fransport Large capacity vehicles with high-sided open or closed-top bodies are tlle mo t suitable for the transport of dllctwork Careful consideration should be given to the
Adequate floor space IDust be provided within tbe building for the site storage of ductvork Such storage shalt make due allowance for thc stOf(ne of ductwork in stacks such that access ~ egt
between them is of sufficient width to pennil the removal of item without interference to
unloading of transport on sit a not all siJes b n fit from the material handlino- and access facilities that exi [ in a manufacturing workshop such as crane- fork-lifts or loading bay Site handJiog facilities along with
adjoining sta ks Ductvork components should be positioned so a to avoid crushing Ductwork of small panel size may be stored horizontally however care should be exercised to ensure that tack sizes are limited 10 within
ehicular acce s restrictions may itilluence the type and ize of transport to be uWised
engtlls of ductwork should be positioned 0
the tmctural strength of the duct sections to prevent distortion of the lower sections within the stack
as to avoid crushing Lengths Witll projections such as branches and bends i1anges girths damper quadrauL should be loaded so as to
54
DW154 S1tciic(ltioll for Plastics Ductwork
85 Internal cleanliness of new ductwork The site storage of ductwork introduces the important cODsideration of maintaining the internal cleanliness of the ductwork R feren e should be made to HVCA documentshybull DWffM2 Guide to Good Practice - internal
Cleanliness of New Ductwork Installations If the above conditioDs can not be satisfied consideration should be given by tJle designer to amending the specification to include for Po t Installation Cleaning as covered by tJ1C HVCA documentshybull TRJ17 Guide to Good Practic - Cleanliness
of Ventilation Systems
APPE DIXC
Fi e Retardant inishes C1 Improvement in the fire retardancy of plastic
ducts can be achieved to varying degrees and is wholly dependent llPOll the surface coating laminating resin selected and construction specification adopted In some instances smoke emission is coILSidered equaUy with other speci fication requirernen ts of the materials resistance to ignition and bumjng It is therefore important for design rs to establ ish the clients and officers detailed requirements and not rely on a tbird party interpretation of fire resisting or fire retardant Where possible the specification should refer dir etly to compliance with a British or European Standard identifying the specific sections applicable There are various types of resin and mat rcLnforcements that can achieve a Class 1 surface spread of flame ratin o when tested according to BS476 Part 7 (1987) This test puts materials illto Class I - 4 in descending order of perfoDllance according to the rat and extent of flame spread over their surfac under standard beating conditions Materials should also be tested for flre propagarion to BS476 Part 6 (1989) Tbi tesr measures the amount and rate of heat evolved by the material when subjected to standard heating
conditions Test results are given as an index of Perfonnance (i) whicb is based on three sub indices (iJ (i1) (h) The higher the value of the Index of Performance (i) the greater is the material s contribution to fire growth The higher the value of the sub-index 0) rhe greater the ease of ignition aod flame spread The highest product performance classification as defined in Approved Document B of the Building Regulations is Class O This is acLlieved if a material surface of a composite ploduct i~ either a) composed throughout of materials of
limited combustibility or b) a Class I material which has a tlre
propagation index (i) of not more than 12 and sub-index (i l ) of nor more than 6
01 J Class 0 is not a cla$sif1cation identified in any British Standard test
There are resin system reported to be classified to Class O when tested to BS476 Pcl1S 6 and 7 however designers need to ensure that such sysrems can be applied to their proposed design In propriety resinmat system available the fabrication techniques and COITect application are critical to the integrity of the reinforcing and clas ificatiol1 For example in some systems the u e of a non-fire retardant gelcont on a fire retardant substrate would reduce the classification For further information see HVCA publication DW144 Appendix D
55
DW154 SplCijiClIliol1 for Plastics Ductwork
x Guidance otes For nspectmiddoton Servicing a d
Clean-ng Access Openings
D1 GE ERAL This appendix highlight in ummary fOI111
the acce considerations that hould be made by the design r iD terms of inspection servicing and cleaning Having considered the seop and the design of the dUCI work system relative to the guidelines outlined below the designer should clearly indicate which levels of acces should be incorporated into the manufacture of a new duct work system (See Table 14 and Note I b low it
D2 DESIGN CONSIDERATIONS
D21 In ptction and servicing requireshyments are set out in Section 15 of Lhis specification
D22 Cleaning requirements are set out in the HVCA pubUcation TRl7 Guide to Good Practice Clean Lines of Ventilation Systems and the guide tates The precise location ize and
type of access would be dependent on the type of ductwork cleaning inspection and te ting metbods to b adopted Care protection and standards of cleanliness prior LO cOlllmisionin o
are set out in th AV A publication DWITM2 Guide to Good Practice Internal Cleanliness of New Ductwork Installations and th guide state Wh re specific limits of cleanliness are required ductwork sball be cleaned after installation by a spcialist cleaning contractor It will b in the interests of tht desioner botb financially and practically to cunsider employing a specialist c1eauing contractor at tbe
outset of a contract to internally clean newly installed ductwork prior to bandover This approach would reali e the following benefit shyi) Tb actual numb r of cleaning
access panels could be detennined to suit the method of cleaning to be adopted (This may be 1 s than the maximum requiremen listed under Lev 13 of Table 14)
ii) Clear directions could b given to the ductwork contractor as to tJle size and location of cleaning access panels that are required to be fitted during the mauushyfaclunng pro s
iii) The specialist cleaning operation prior to commi ioning vould enable the cleaning contractor to verify the practical acee requirement for the future cleaning operation associated -vitb a regular maintenance programme
iv) A specialist cleaning operation prior to commissioning would allow the designer to omit from the speeilicatiolJ the DWrrM2 requirem nt for factory sealing protection wipe downs and capping-off
v) Specialist Ieall ill 0 to the measurable standard defin d in TR17 will allow an objective definition of cleanline to be achieved
Car ful consideration must be gIven by the designer to the practl aJ problems associated witb the manufacture and fitting of suitably si Led access panel on small cross section duct and on the circular faces of rouod and flat oval ducts in particular
D23 Special con ideration must be given by the de igner to the practical problems associated with gaining personnel access to heavily congested ceiling areas and multi-la red du twork systems This approach would avoid
56
DW154 Spfciication for Plastics Ductwork
the possibility of access panels being D3 ACCESS 0 IN-LINE EQUIPMENT incorporated into a ductwork system at the This appendix unly covers acc il1spection manufacturing stage that were later found in through the ductwork body adjacent to an item practice to be inaccessible for either ervicing of in-line equipment and not openings in the or cleaning activities equipment itself
able 14 Acce requirements for inspection servicing and cleaning
HVCA PUBLICATIO REFE NeE (uidtgt 10 Gund Prartict
Adjace t OW144 Cleanliness orVcnlillltio S~lcr~ fRjJ7
in-line LeyeJ 1 Level 2 Level 3 ite sequipment pcdionSen lcin~ Section d C1eaniJl( SUn(O)lnspc lion Palle ltk~m_n
2011 (minimum OiL Jubje-ct to duct ~zel (ft~ -Panels
Control Da pcrs One (inspection) 203 One 300 mm x 200 mm Both sid Fire Dampers One (sCTjdJl~) 20211 One 300 0101 x 200 mm One side HeatingCooling Coils One (inspedion) 20213 One 300 mm x 200 mm (lIpstream) Both sides Attenuators (rectangular) None required One 300 mm x 200 mm (downstream) Both sides Attenuators (circular) one retluired One 300 mm x 200 mm (downstream) One side Filter Sections One (inspection) 20212 one required Uoth sides Air Turn Vanes None requjred None required Both sides Changes of Direction None required one required One side In-Duct FansDevices One (inspection) 20213 None required Both sides l
1 In the absence of any indication by the designer only Level ) access will be jncorporated into a new ductwork system
2 Tbe panel izes associated with Lev lis I and 3 acee s ar e middottablished by reference to Section 20 of DW144 and Section 2 ofTRll7 respectively
57
DW154 Speclfifatio for Plastics Ductwork
pA XE
B-bliography Included in this Bibliography are technical pUblications which may be of interest (0 ductwork designers fabricators and erectors and to tho e in the heating ventilatlng air conditioning industries generally nquiric should be made of the relevant organisation at the address quoted Since its publication other addresse contained within 0V154 mav have changed and some pubJicalions may have been superseded
HEATING AND VENTILATING CONTRACTORS ASSOCIATION
4 Palace Court London W2 4JG Telephone 020-7229 2488 Fax 020-7727 9268
Orders fo FlY A Publications Old Matlsion House Eamont Bridge Penrith Cumbria CA 10 2BX (Telephone 01768 864771 Fax 01768 86718) Email hvcapoblicationshvwelfarecouk DWn 44 pe ilicatiun for sheet mctal duclwork (Iow- mediulllshy
and high-pressure) 1998) DWIl4 A practical guide to dUGI ork I akage te ting
(revised 2000) DWII54 Specification for plastic~ duct rk DW171 Guide to good Practice for kitchen venlibtion system DW191 Guide to good pracuce glass fibre ductwoJk DwrrMI Acceptance cheme for new products - Redangolar cro
joint classification Guide to good pra tice - Internal cleanliness of new ductwork installations Guide to good practice for the design for the Installation of lire and smoke uampers
J 1Other puhlications
HampV safely guide 5th edition JS2 Tool box talks JS5 Weldlng Safety booklet JSI9 afety facts bo klet Fact sheets 1-24 2nd edition JS2J COSHH manual volume 1 Advice on compliance with the
regulations 1521A CO I-rH manual volume 2 Asses mcnt h ets JS23 Ri k management manual TR3 BrazinltT and bronze welding of copper pipework cUld sheet
(I 976) TR5 Welding of carbon steel pipework (1980)
TR6 Guide to Good Practice for Site Pre sure Testing of Pipework (19 0) Guide to good practice cleanliness of ventilation Ylem
CHARTERED IN TITUTlO OF BUILDING SERVICES E G EERS Delta House 222 Balham High Road London SW12 9BS rTelephone 020-8675 5211 Fax 020-8675 5449) CIBSE Guide Volume A Design Data Volume B In tallatiol1 and quipment Data Volume C Reference Data
CommlssioniJIg Codes These Codes eover the preliminary checkS eUing to work and regulation of vanous catcgories 0 plan The Codes give a guide to design implications Series A Air Distnbution Systems Series B Boiler Plant
ri s C Automatic Conlrol ystems Cr1es R Refrigerating Sy terns
Sene iN Water Distribution Systems
Technkal Memonllda TM 4 Design Notes for the Middle East TM bull Design otes for Ductwork TM 13 Minimi iog lhc Risk of egiounaires Disease
Research Reports RROI95 Ventilation system hygiene - A review of published
infomlatioo on lhe occurrence and ffects of Olltamination Rl~02J95 Air-to-air heal rec v ry RR0395 rnfluen e of HV C on smoke detectors
ATlONAL ENI [ERING SPECIFICATION LfMITED Southgatc hamber 3739 Southgate Street Winchester S023 9EH (Telephone 01962 842058 Fax 01962 R(8982) BUfLDING S RVICES RESEARCH AND [ ORMATION ASSOCIATIO Old Bracknell Lane West Bracknell Berkshire RG 12 4AH (Telephone Brackl1eU (01344) 426511 Fax 01344 487 -7 )
Application Guides AGln4 De tglJing Vana~le Volume middotylans for KOOnl
iir Movement AG1I91 Commissioning of V Sylcms in Buildings 11 6194 Fire Dampers
B) 94 cntiJalion or KitcneTls
AG389 The Commls ionin of Air Systems In Buildmgs AH2192 Commissioning of Bern - A ~ode of Practice TN2417 I Fire Dampec il) Ventilating Ducl
BEATING VENTILATING A AIR CONDITION G MA UFACTURERS ASSOCIATIO (HEVAC) HEVAC Henley Road Medmenham Marlow Buck SU 2ER (Telephone 01491 578674 ox 01491 575024 Emoimiddot infofetacouk)
Publicatjons Air Diffusion Guide Guide to Air Handling Unit Leakage Testing Guide to Good Practice Air Handling Unit Real Room Acoustic ~ st Procedure Specification for the ertiiicatioll ofAir Filters Method of Test for Water Rejection PerfOnTlatce of Louvrcs Subjected 1(1
Simulated Rainfall Test Procedure for Acoustic Loo cs Specification 10 Floor GrilJes - Types Performan e and Method ofTest Specification for the Determination of the Collection Efficiency of SilJ1d
Trap Louvre Domestic Mechwlical Vclltllalion Systems with Heal Recovery Fan Application Guid
~an and Ouctwork Installation Guide Guide to Fan Noise and Vibration
pecification of Requirements for JallJral Smoke and Heal Exhausl Ventilators
pecification for Powered Smoke and Heat Exhaust Ventilators
Specification of Requirements for Smoke Curtains Design Gujue of Smoke Ventilation for Single Storey Lodustrilll Building~
Including those with Mezzanine Floor and IIi Racked Storage Warehou es - Issue 3
Guidance for the Design of Smoke entilation YSlem for Covered and Undergrollnd Car Parks - lssue 1
Application of SOloke Control Equipment and Syst m Guid to Good Practice - Isue J
58
DW154 Sp(C~tiifitiol for Plastics Ductwork
BRITISH STANDARDS INSTIT TION Sales Department 101 P ntooviLle Road London NI 9ND (felephone 020-78 1 78801)
CP 413 1973 Ducts for building ervices
SS 476 Fire tes on building matenals and lruc(ure
Part 4 19 4 Non-combustibility lest or materials
Part 6 I Fire propagation lest for materials
Part 7 1993 Surface spread of tlarnJ tesls for materia
Part 20 1987 Fir resistance of elements of construction
Part 21 1987 Fire r sistlUlce of loadbeanng elements of construction
Part 22 1987 Fhe istallceofllon-loadbearing elemcllts ofconsttuclion Part 23 1987 Contribution of componcnts to the fire resistance 0 a
structure
Part 24t987 Fire resi lance of wl1lilation ductl
SS 5588 nan 919 0 Fire Precautions III thc desIgn and OOSlnJ lion of buildings
S 729 1971 Hot dip galvanized oatiugs (or irOIl aod stcel articles
BS 1449 Steel plate sheet and Irip
Pan 11991 Carbon steel plate heel and strip Part 2 1983 Stainless steel plate sheer and strip
and
B middotENJOI49-2 996 BSEN 10149- 1991)
BSEN 10131 1992
BSEN22063 Sprayed metal coarings 1994 Protection of iron and steel by aluminium and zinc against
atmospheric cOlosion Irotectiotl of iron and ste I against corro ion and oxishydation at elevared temperatures
BS 353 1981 Glossary of lerms relnting to thermal insulation
BS ISO 1479 Self-tapplngscrewsandmetallicdri c crew
B -lSO 7049
1994
B 4800 1989 Painl colour for building purposes B 4848 l0 rolled structural steel sections
Part4 1972 Equal and unequal angles BS 5422 1990 Specification for the use of therm illuating matcriulS
SS 5720 1979 ode of practice for mechanical veutilating and air C 11shy
dirionin bull in building
l3S PR 12814-1 Bend resting for plasric welds
SS PR 12814-2 Tensile testing for plastic welds
SS PR 13067 Appro altesting for plastic welds
BS PR EN I 100-] Vi ual in pection ofplaslic welds
SHEET METAL AND AIR CONDITIONING CONTR-CTORS NATIONAL ASSOCIATION INC (SMACNA) Headquarters 420 I Lafayeue Center Drive Chanlilly Virginia 2051-1209
Mailing Address pa Box 221230 Cbantilly Virginilt120 153-1230
Telephone (703) 803-2980 Fax (703) 803-3732
Accepted IJJdustry Pl3Gtice for Industrial Duct Constnlelion 197 ) i-rchitecmral Sheet kwl Manual ([993)
Comractors Guide lor Modification 10 ooslruerion Colllraets 1993 Ducted Eleclric Heat Guide for ir Handling Ssrerns (1994)
En~rgy ollservatioD Guidelines (1984) Energy Recovery Equipment yslClllS (199l
Fibrou GIns Duct onS1ntClion Standards (1992)
Fire Smoke amp Radiation Damper In tall Guide for HVA Syst ms (1992) Guide t leel Stack 1(95)
HVA Air Duct Leakage Test Manual (19 ) HVA COlllmissioning lvlanual (1994)
H A Duct Construction Standards-Metal amp Flexible (1995) Addendum 01 (Nov 1997)
HVA Duct Systems Inspection Guide (1989)
HVA ySlems-Application (1986) nVAC ByternS-DLlct D ign (1990)
HVi Systems-Testing Adjusting amp Balancing (1993)
indoor Air Quality Manual (1993) tcheu quipment Fabrication Guidelmes (1990)
Managers Guide for elding (1993)
Rectangular Industrial Duct Cons1TUction Standards (19 0) Round Industrial Duct oustmction Standards (1977)
Sei mic Restraint Manual (1991) (wl Appendix E 1993) SMACNA Ma le Index ()fTechnical Publications (1995) Tbennoplnstic Duct CPY ) Construction Manual 1994)
DEPARTME OF THE ENVIRO MENT (Publications Centre) H Stationery Oflice 5 Nine Elms Lane London SWS 5DR
MampEJ 011972 Electrical in tallat1011 in buildings ( ew Editiou)
IampE 0319 Healing hot and cold wat r steam and gas losla1lations for buildings
M amp - No4 1970 Central heating and hot and cold ~ ateT in tallations for
dwelling
M amp ENo100 1971 Mechanical ventilation for building~
ASSOCIATION FOR SPECIALIST FIRE PROTECTlO As ociation House 235 Ash Road AJdershot Hampshire GUl2 4DD
Telephone OJ25221322 Fax 0 J252 333901
lublicalioos Fire Ratcd and moke Outlet Ducrwork An Industry Guide t Design and InSlalla lioll
HEALTH AND SAFETY EXEC TIVE Rose Court 2 Southwark Bridge London SEl 9HS Telephone 020-7717 6000
TWJ THE WELD G TlTUTE Abington Hall Abington Cambridge CB16AL Telepbone 0 J223 89162
Publication DatJ Oil w~ldll1g of lhermopla lics
59
DW154 wciiwlioll for Plastics Ductwork
A -=--DIX
Factors
Specific gravity shy pp = 091 approx UPVC = 14 approx
Some miscellaneous conversion factors
To convert
Length Inches to millimetres Feet to metres
Multiply by
2540 03048
To convert
Millimetres to inches Metres to feet
vIultiply by
003937 3281
Area Square inches to square millimetres 6452 Square millimetres to square inches 000155 Square feet to square metres 00929 Square metres to square feet 10764
Volume Cubic feet to cubic metres Cubic feet to litres Gallons (UK) to litres
002832 2831 4546
Cubic metres to cubic feet Litres to cubic feet Litres to gallons (UK)
35315 00353
022
Mass Ounces to grams Pounds to kiJograms Tons to tonnes
2835 04536
1016
Grams to ounces Kilograms to pounds Tonnes to tons
003527 2205
09842
Volume flow Cubic feet per minute to cubic Cubic metres per second to cubic
metres per second 0000472 feet per minute 2119 Cubic feet per mIDute to litres Litres per second to cubic feet
per second 04719 per minute 2119
Motion Feet per minute to metres per second 000508 Metres per second to feet per minute 197
Pressure Inches water gauge to millibars 2491 Inches wateJ- gauge to pascals (Pa) 2491 I Pa = I ewton per square metre = 10-2 millibars
60
Heating and Ventilating Contractors Association Esca House 34 Palace Court London W2 4JG
Tel 020 7313 4900
e-mail contact Itvcaorguk web site wwwhvcaorguk
Fax 020 7727 9268
DW154 SfJcdJicatiOt for Plastics Ductwork
Table 10 Minimum constructional requirements shy
Longer Side Minimum Sheet Thicknes and
GRP Reinforcement
UPVC FBIPP 1 2 3
mm mm mm Up to 1000 3 plus 3 plus
06 kgm2 06 kgOIl GRP GRP
1001 to 2250 45 plus 3 plus 06 kgm 12 kgm
GRP GRP
2251 to 3000 45 plus 6 plus 12 kgm 12 kgm
GRP GRP
Cross Joints
UPVCFBPP 4
mm socket amp spigot
as Fig 30 or flanged as Fig 29
75 x 9 flange welded on both sides as Fig 29
75 x 9 tlange welded on both sides as Fig 29
rectangular GRP reinforced ducts
SlifTeners Maximum Spacing Between
JointsSljffeners UPVCIFBIPP UPVCFBPP
5 6 mm mm
75 x 9 flat 800 as Fig 31 or
50 x 50 x 5 plastic or MS inverted angle as Fig 32
or tormer as Fig 33
75 x 9 flat 600 as Fig 31 or
50 x 50 x 5 plastic or MS inverted angle as Fig 32
or former as Fig 33
75 x 9 flat 600+shyas Fig 31 or 50 x 50 x 5 plastic
or MS inverted angle as Fig 32
or former as Fig 33
Note 1 On rectangular duct up to 400 mm longer side no stiffeners are required 2 Applies to Tables 10 amp I I For COlJstructional operating temperature limits refer to Part 2 clause 5A 3 Tables 10 amp II apply to all pres ure classes up lo ]500 Pa
Table 11
Diameter
1 III
lJp to 1000
1001 to 1750
1751 to 2500
Minimum Sheet Thickness and
GRP Reinforcement
UPVC FBPP 2 3
mm mm 3 plus 3 plus
06 kgm 06 kgm GRP GRP
45 plus 3 plus 06 kgm2 18 kgm
GRP GRP
6 plus 6 plus 12 kglm2 18 kgm1
GRP GRP
Cross Joints
UPVCFBPP 4 III
socket amp spigot as Fig 30 or flaoged as Fig 29
75 x 9 flange welded on both sides as Fig 29
75 x 9 flange welded 00
both sides as Fi 29
inforced ducts
Maximum Spacing Between
JointsStiffeners UPVCIFBPP
6 mm 2400
800
600
Stiffencrs
UPVCFBPP 5
mm 50 x 9 flat as Fig 31
75 x 9 flat as Fig 31 or former as Fig 33 75 x 9 tlat as Fig 31 or t()rmer as Fi 33
ote On extruded tube tip to 600mm diameter no stiffenergt are required
30
DW154 Specificatioll for Plastics Ductwork
G - Cross joints and tiffeners
Fig 29 Flange Joint Fig32 Stiffener shy inverted angle
M artiPfCuQkbdd erttpObri) Wl111 RP tlddtlt
_- GRPloliu] lh~
Fig 30 Socket and spigot joint Fig33 Stiffener shy use of former
Fig 31 Stiffener Flat
I Pv FlPP ~ ~lmJaDUA1) d
OMrlQ rrnall 1( tQlS
25 STANDARD COMPONENT DRAWINGS AND ABBREVIATIONS
251 The illustrations in this section not only highlight where applicable geometric limjtations for the de ign and manufacture or ductwork components but also recommend
standard drawing representation terminology and abbreviations for both duetwork components and some of the more commonly used ancillaryplant items
252 Designers and surveyors should note that bills of quantities should provide a full description
3)
---
v
DW154 Spcc(fim(ml for Plastics Ductwork
Fig 34 Linear Thermal Expansion
u c 0 N ro 0)
b 0)
S
sect0
5 oS cl) 0)
~
on ~ ltl
c U
-30 -20 -10 0 10 20 30 40 50 60 70 80 90 TEMPRATURE C
~ V
-
~~c_ ~
~V
V ~
-7 ~
-- ~V ----
v
-6
+14
+12
+10
+8
+6
+4
+2
0
-2
--4
ig 35 Typical Design Stress tor UPVC and P
7
6
r shy 5E
-c E----0 4t) VJ 0)
ci5 0Jl 3
~
0)
Cl
2
1
o
UPVC
1
000
1
1
pp
- r-- shy r----- shy - t--shy I
__0
-30 -20 -10 0 10 20 30 40 50 60 70 80 90 TEMPERATURE C C
Note Figso 14 amp 35 shaded area refers to GRP reinforced duct
32
DW154 Speciicfltirm for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - REC ~NGULAR
Splilt~r Posilion W-mm pliucr
A B c 40]--QOO 1 W - -
601-1000 1 W4 Wf2 -
1001-1800 3 WI W3 W2
FIG DRAWING DETAfiS
tU]36 ATI Straight Duct with socket and spigol joint
rn [037 Straight Duct with flanged joints
[I []38 Straight Duct with flanged joints
rkJ Short Radius Bend
39 Applies to any augl and for duct up to 400 n11n wide
Minimum (I1m31 radills = 100 mm
Medium Radius Bend (a illustrated)
[kJ Applies to any angle
40 Long Radiu Bend Similar but radius = W
Throlll radius = W2 Applies to any angle
- Short Radius Bend with plitlers
I -shy -shy u co - t lt Li--_ 41 t 0 ~ I I I
~ I
L 1W
Minimum waal radius = 100 mm Splitters not required in bend angle less than 45deg
42 QJ1 Square Bend with turning vanes ij
3
DW154 SP(L~ficatioll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - RECTANGULAR
FIG DRAWl G DETADS
43
~
I v
L L Radius Tee with internal deflectors
44
~ Radiussed Twin Bend
45
Imiddot
er Swept Branch
46 U-
Sqoare Tee with Turning Vanes
47
~ f
Breeches Piece
48 0 y l Piece
34
DW154 Specificatioll for Plastics Ductwork
STANDARD COMPONENT RAWINGS - ECTANGULAR
55
54
51
50
53
52
49
FIG
~MX
RAWlNG
DmiddotMAX
EfjMAX
Minimum throat rndius = 100 mm
Rectangular shy Round Transformatioll
Eccentric Taper 225deg max in either plane Spliller are required for angles greater than 225deg and hould bi eet the angle between any side and duct centreline
DETATLS
Angled Offset
OUset Taper Splitters are required for angle greater than 22 0
and shoold bi eet the angl between any side and dUCI centrelinc
Mitred Offset
Concentrk Taper 2250 max in ither plane SpUtters are required for angle greater than 225deg and should bisect the angle between any side and duel c ntreline
Radiussed Offset
35
DW154 Splcilcuthm for Plastics Ductwork
STANDARD COMPONENT DRAWINGS ~ RECTANGU AR
Branch ducl DimCllsions widlh (W) (A)
urnl mm up lO 200 75
300 100 400 125 600 150
Ocr 600 200
FIG DRAWlNG DETAILS
56 poundplusmni~~ Rectan~lar - Flat Oval Transformation
57 [ Square Branch
58 er Angled Branch
Branch dUCI Dimensions wfdth (W) (A)
[- mm mm59 3shy Shoe Branch Up (0 200 75
--shy AIshy + 300 100
400 125
450 MAX 600 150
Over 600 200
Branch duct DimensIOn
rP X width (W) A)
60 - 1--shy _
~ mm mm
Bell Mouth Branch pto 200 75 300 100 t 400 125
600 150 Over 600 200
0=0 61 -
~ Bell Mouth
- shy T 4-5deg M x
--I 1-shy
TJ
62 X I ] I
Tele-scopic Joint I Illustrated with flangeL
X63
SBD Single Bladed Damper
36
---
DW154 Spedicatioll for Plastics Ductwork
STANDARD OMPONENT DRAWINGS - RECTANGULAR
DRAWING DETAILSFIG
64 on-Return DamperNRD shyshy
shyXbull
Multi-Leaf Damper Can be piggoted or flanged oppo cd or parallel blade
Alternative controls areshy
q p [gtshy
J HD65 Hand
~MD otori ed
PO Pneumalic
L-lt
l 13G 66 Blast Gate DamperX X
FireSmoke DampersSleeves
211r Ratinggtshy----
L_-
---
----
r----
Ir-- shy
IL- _-l
2hr
With i tallation frame
67 41 r Rating
4hr
Smoke damper SD
Intumc cent Sleeve L-d
37
DW154 Specijicutiolt for Plastics Ductwork
FIG
68
69
70
71
STANDARD COMPONET DRAWINGS shy REC ANGULAR
DRAVING DETAILS
gtshy Access Openings
AP 6 Access Panel - Rerno able
w [ ~ Access Door - Hinged
I ~le Inspection Cover
le -I reg -lt
~X X Flexible Connection
~ Drop Cheeked Radiussed Twin Bend
U Drop Cheek Bend
I
72 Air Flow SymbolX
38
DW154 Specifim[ioll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - ECTANGULAR
FIG DRAWING DETAILS
73
74
75
76
77
Q
Q
rp---t
~
V- I Ir---I
JL --11
THE ABOVE DETAILS TYPICAL PLENUM
Air Terminal Plenums
Plenum with side connection
Plenum with top connection
Cover plate with connection
Special plenum with connection
elescopic conn ction in direction of air flow
39
DW154 SpecijicotiOll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG
78
79
80
81
DRAWING
-23~---pound3-(MALE) (FEMAJE)
-t=j--_j(--d-shy
--L
~ THROAT RADI S= D AS T NDARD
e ~
THROAT Rjf)lU = D A MU)
DETAILS
Straight Duct With male and female connectors
Straight Duct With flange joint and slip joint
Bend MouldedIFormed Applies to any angle ego 30deg45deg60deg90deg Medium radius bend as illustrated Long radius similar but throat radius 0
Segmented Bend 90deg four section minjmum as illustrated
Other Angles 60deg = 3 sections 45deg = 3 sections 30deg = 2 sections
I
i
40 shy
DW154 Speciicafinll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG DRAWING DETAlLS
82 Segmented Twin Bend Radius = D2 max
May also be fabricated from tube
83 Equal Tee MouldedIFormed
84 -~ 1in Bend MouldedIFormed
85 Taper Concentric 1 0 as iUu trated Eccentric 30deg iJJcLuded angle
86 Short Taper
41
DW154 SpcUicatol1 for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG DRAWING DETAILS
87 30 max Offset
Angle Branch
Bran h dUCI Dimcnsions dia (D) lA)
Shoe Branch mm mm 88 Cl
Off rectanguJur Up 10 200 75 lOO 10 400 125
- 00 150 Over 600 200
Bl1IllCh duct DimenlOns din (D) (A
~-$a-Conical Branch mm mm
89 Also acceptable with Up 10 200 r
full conical surface 300 10
400 125
END VrE -shy 600 150 Over 600 200
90
m 75
100 12 150 200
mm Up to 200
_ 300 400
600 Over 600
iUtred Branch
Shoe Branch
J-L----U ~ Bell oulh Branch
ENDV1EW
93
92
91
42
DW154 Specificatiol for Plastics Ductwork
STANDARD OMPONENT DRAWINGS - CIRCULAR
FIG
94
DRAW G
I
~ 30deg 090deg
Breeches Piece
DETAILS
95 amp-----~ Blank End
~-----p Multi-Leaf Damper Can be piggolcd or fianged opposed or parallel blade
Alternative controls areshyri=-+- L-T~
I
---
LT~
I r- -
-+1
J HO Hand96
bMD Molori cd
PD Pneumatic
tl-shy bull
Single Bladed Damper 97 ~ saD
on-Return Damper Vertical application only 98 m~D
43
DW154 Sf1tcificatioll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG
99
100
101
102
DRAWING
$ I-
2hr
1 4hr
SD
~v I I
CO TINENTAL COWL
DETAILS
Iris Damper
Fi reS moke Dam persSleeves
2hr Ratillg
With installation frame
4br Rating
Smoke damper
Intumescent Sleeve
Access Openings
Access panel - removable
Access door shy hinged
fnspection cover
Discharge Continental Cowl
44
DW154 Sp(Cii(ltJll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
DRAWINGltIC DETAns
-
I
I
~
I I I High Velocity Discharge Terminal 103 I
I
I I
J I I 1 ~--
Offset Stack Discbarge Terminal 104 1
~ I e --(-
I
N
I
I
I~
I I Vertical Oischarge with Weather Cowl 105 I
--1--1 I
I
GAPI I
RTl AL DISC) lARGE WITH W ATIIER COWL
45
DW154 SpecUicatoll for Plastics Ductwork
STANDARD COMPONE T DRAWINGS - PLA TEQUIPMENTIMISCELLANEOU
FIG DRAWING DETAILS
106 ~~~ Rectangular Attenuator
107 ~- Circular Attenuator
108
~ Beod Attenuator
109 J ~(f) Heating Coil
110 J ftte Cooling Coil
III Jc[ Electric Heating Coil
112 X F
Humidifier
113 [H XX Axial Fan
114 ~fB1famp Noo-standard Ductwork Cross hntchillg (of any separate type) indicates by reference to a key any non DVil54 ductwork system
115 2llIIIIJIIIIIll Flexible Ductwork
46
DW154 SJeCUicll(iol1 for Plastics Ductwork
TABLE 12 - STANDARD ABBREVIAT ONS
ABBREVIATION FLL
AD Acces Door
AFF Axial Flow Fan
AHU Air Handling nit
All Aluminium
AP Acess Panel
AT Attenuator
AV Air enninal Unit
BE 81ank nd
BQ Blast ate Damper
CC Cooling Coil
CF Centrifugal Fan
CTA Cross alk Attenuator
CVU Constant Volume Unit
DP Drain Point
EEC Electric Heating Coil
El Expansion Joint
FAl Fresh Air Inlet
FA From Above
FB From Belo
fBPP Fabric Backed Polypropyl-ne Sheet
Flexle Flexible Connection
lexfD Flexible Du t
C False Ceiling CO an oil Unit
fD Fire Damper
FFL Finished Floor Level
FJ Flanged Joint
FOAM Rigid Polyurethane Self xtinguishing Foam
FOB Flat on Bottom
FOT Flat on Top
GAM Galvanised after ManufacttrJc
GRP Glass Reinforced Plastic
GSS Galvanised Sheet Steel
HC Heating oil
HD and controlled Damper
HH Hand Hole
HL High Level
HVD High Velocity Discharge
IC Inspection Cover
ID lri Damper
IFS Intumescent Fircleevc
47
DW154 Specification for Plastics Ductwork
TABLE 12 - STANDAR ABBREVIATION CONTINUED
ABBREVIATION
IU
L
tv1D
MS
NRD NTS
OBO
OE
PHD
PD
PP
PP
PRD
PVC
RFC
RSC
R
SBO
SO
S1 TST
SSL
TA
TB
TO TJ
TP
TV
TV
OS
UPVC
S
V
VAV
50 RSA
FULL
Induction Unit
Low Level
Motor controlled Damper
Mjld Steel
on Return Damper
at to cale
Opposed Blade Damper
Open End
Parallel Blade Damper
Pneumatic controlled Damper
Polypropylene
Self xtinguishing Polypropylene
Pressure Relief Damper
Polyvinyl Chloride
Rolled Form Chamlel
Rolled Steel Channel
R fUnit
Singl Blade Damper
Smoke Damper
Slip Joint
Stainl t el
tructural Slab Level
To Ab vc
To Blow
Top Down (In Direction of Flow)
Telescopic Joint
Test Point
TU111iog Vane
Top Up (In Direction of Flo )
Voles Otherwise Stated
Unpl3sticisecl Polyvinyl Chloride
Underside
Ultra Violet Light
Variable Air Volume
Rolled Steel Angle (Vith Size)
48
DW154 SJeriiflllioll for Plastics Ductwork
A2 DUCT PRESSUREAPPE DXA Ductwork con truct d to DWIl54 will bebullbullbullbullbullbullbullbullbullbullbullbullbullbull
Air Leakage From Ductwork To be read in conjunction with DW143 A practical guide to Ductwork Leakage Testing
CAUTION As highlighted ill both this docul1lenr and DW14 I lot ellough emphasis can be placed 01 the fact that except for high pressure class C the much more stringent ductwork constructional standard brolght about b the general acceptance of DW154 have irtlally negated the requirement for leakage-testing It is essential lO realise lhat except where it is mandatory this doclllllelll is nOl an endors ~lIlent of the rourine testing of ducts bllt purely a guide to outline the procedures for cononnity with the air leakage limits ill Table l Where the specified methods of assembly and
A3sealing of dlcls are u ed a vi ual inspection wil ordinarily sl~fll e for ver(iatioll of a well engineered and a ceptahfy airtight COl1strucrioll WHERE NOT MANDATORY DUCT LEAKAGE TESTING IS GENERALLY AN UNJUSTIFIED AND SUBSTANTIAL EXPENSE
A1 INTRODUCTION L akage from ducted air distribution systems is an Lmportant consideration in the design and operation of ventilatjon and air conditioning middotystems A ductviork t)ystem tbat ba limited air leakag within defiucd limits wiH cnsUft
that tile design characteristics of the sytem can be maintained It wilJ also ensure that energy and operatLonal cosb are maintained at optimum levels DucLwork constlucted and Ulstalled in accordance with DW154 should minimise a level of air leakage that it) appropriate to tll operating static air pre sur in tile system
A4However it is recouuised that tbe environment in wtJich middotystems are installed is not always conducive to achieving a predictable level of quality in term of system ajr leakage and it is therefore accepted that designer may sometimes require tlle ystem to be tested in part or in total It should be ecogni ed that the testing of duct systems add a ignificant cost to the installation and incur some extra tjm within the programme (Se 47 and 64 re mandatory te-sting)
manufactured to a structural standard that is compatible with the system operating pressure There are three classes of duct con truction to eorre pond with the three pre ure clas meations Class A Lo pressure ducts suita le for a maximum positive operating pressure of 500 Pascal and a maximum negative pressure of -500 Pascals Class B IVledium pressure ductmiddot suitable for a rnaxilnuJJl positive operafjn o pressure of 1000 Pascals and a maxllnum negative pre sure of -750 Pa cal Class C High pre sure ducts suitable for a maximum po ilive operating pressur of 2000 Pa cals and a maximum negativ pres ur of -750 Paltcals
LEAKAGE FROM DUCTWORK Leakao-e front pia tic air ducts occur at the joint~ and is therefore proportional to the total surface area orthe du twork in th system Tb level of leakage i imilarly related to tIle air pres ure in th du t system and whilst there LS n precis formula for calculating the level of air los it i generally accepted that leakage will increase in proportjon to pressure to rbe pOvver of 065 The effect of air leakage from high pressure velocit ductwork is critical tn terms of system perfomlan dege energy consumption and the risk of high frequency noise as ociated with leakage These problems are le critical with medium pressure 10 ity systems but should be con idered Low pres mevelocity ducts present the lowe~t
ri k in tenn of tbe effect of leakage on the operation of the s stern
SYSTEM LEAKAGE LOSS As there i no di ct relatLonship between th volume of air conv yed and the surface area f the ductwork sy tern required to match the building configuratmn it is difficult to express air leakage a a percentage of total air volume Similarly the operating pressure will vary throughollt lh 3 system and a leakage is related to pre me the calculations ar comple However it is generally ac epted tbat in typical good quaJjty systems the leakage from
49
DW154 Specificatioll for Plastics Ductwork
each class of duct llnd r operating condition will be io the region of CIa S A low pressure 6 Clas B medium pres un 3 Clas C high pressure 2
A5 SPECIFYING AIR LEAKAGE TESTING Re peeting both the co -t and programme implications a sociated with te ling du 1 for leakage the designer may for example indicate that a particular system is te ted as follow
a) High pressure ducts - all tested b) Medium pr ssure duets - 10 of the
ductwork shall be s eet d at random and tested
c) Low pre sure - unte ed In any case where a random te t i elected for medium pre sure ductmiddot the followin c1au~e is suggested for inclusion by the de ign r
The designer hall elect at random a maxirnwlI of 10 of the dUCl system to bt tested for air leakage The duct hall be tested af the pressure recommended in Table J3 for the assifi atiol for the ectiol1 of the ductwork that is to be tested The tests shall be carried Ollt as the work proceeds and prior to the application of thermal insulation In the event of test failure of the randomlY selected section the designer shall have The right to select two La1her e tiolls at random for resting Where succes ive failures are identified there shall be a Tight to require rhl COl11raCWr 10 apply remedial attention to the complete ductwork system Th contractor shall provide documented eviden e of the calculalions used to arrive (1
the allowable 10 I for the section to be tested and the client or his agent shall willess and sign the results of the test
able 13 Air leakage rates
Maximum leakage of duct work Static
prcssUft Low-pressure edium-prc-sure I Iigh-prebull me diJfercntial Class A Class B Class C
1 2 J 4 Pa Litres per second per quare metre of surface area 100 054 018 ZOO 084 028 300 110 037 400 132 044 500 153 051 600 058 019 700 064 021 800 069 023 900 075 025
1000 080 027 1100 1200 1300 1400 1500
029 030 032 033 035
1600 1700 1800 1900 2000
036 038 039 040 042
Note Recommend d mean test presures are highlighted iD bold type with the actual selection being left to tll test operator
50
DW154 Sfeeiieaioll for Plastics Ductwork
A9
A10
and air leakage classification for the y em under test
DESIGNERS CALCULATIONS The designer can middotaJculate with reasonable accuracy the predicted total loss from a ystem by
a) Calculating the operatin presure in each ection of the sy tern
b) Calculating the surface area of the ductwork in each correspondin pre lire s ction
c) Calulating the allowabl~ los at the operating pressure for each ection of the system (see table 13 for allowable leakage figures)
VARIABLE PRESSUR S IN SYSTEMS De igner can achieve significant co t saving by matchina operating pressures throughout the system to constmctional standard and appropriate air leakage testing eO the practice of specifying construction tandards for whole duct sy tems based on fan discharge pre sure may incur unnece sary costs on a project For example ome large sy terns ould well be classiC ed for I akage limits as follows
Plant room risers CJas C Main floor distriblltJou CIa B Low pre sure outlets Cla A
A6 SPECIAL CASES There may be ~itLlations on a project where circumstance dictate thal pecial consideration be given to containing air loss s eg a long mn of duclwork may incur a di -proportjonate level of air 10 s In ca es such as thi example the designer can specify an improved tandard of airtighmess ie 80 of alJo~able 10 s for la B Ju ts The designer sbould not specif a CIa C t sI at CIa s C pressure for a CIa s B ducl
A7 SUGG S ED RANGE OF TES ING
A8 TESTING OF PLANT ITEMS Items of inline pJant (eg Fig 106 to 115) will not normaUy be included in an air I akage test The dllctwork contractor may indud such itelllS in tbe te t jf rh quipm ot has a certificate of COnfOlnlity for Ihe pres ure clas
bull High pressure duct bull Medium pre sure ducts bull Low pre sur ducts bull Exposed extract syst ID bull Ceiling void extract
systems bull Secondary ducts from
VAV or fan coil units bull Flexjble duct bull Final connections and
branches to grille and diffusers
100 test See A5 Untested UDt sted
Untested
Untested Untested
Untested
SI
i
DW154 SJecijicafion for Plastics Ductwork
ig 116 Permitted leakage at various pressures
Leakage in litres per second per square metre duct surface area
Vgt
o ltgt 0 ltgt N
ltgt Cgt
0 0 cc
0 0
~
g =
g ~
c 0
J
ltgt 0 I
~ ] tn
ltgt ltgt
In ol
~ 0 ~ 8 ~
~
c ltgt ltgt
~ CJ
~ ~ ~ ~ 8
0shyij
~ ~ ~ t
ltgt ltgt 00
l
~
~ Q
c C
~ rshy
e ltgt
I 1
I Cgt ltgtv
c Co ~
~~ ~ 10
I
0 Cgt
fJshyq 410 ) 1 ltgt
ltgt N
~ shy ltgt ltgt
~ I 1
c
52
DW154 Specificatio for Plastics Ductwork
Example of a completed test sheet Test No
General
Name of job N~ jC43Pt(r2lef Building Repound ~(~~0
Part 1 - Physical details
a Section of duct work to be tested ~(diffPIfff~el1f3rd Floor
b Drawing Number g91~~ c ssure aSSJ L atlOn V~Jl~IRfYgtg~~lPre Cl T Class C
d Test static pressure -(9 raErq~ ~~~~-~~J~~~ ~~ ~~~~ll
Leakaoe factor 9~-tre3$ecMz I OM REFTOTABLE 13)e b bullbullbullbullbullbullbull
f Surface area of duct under test Q~tJJItetre$ CPROMCALCU TIO BELOW)bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull ampampamp bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull
g ]Vlaxi mum permitted leakage -~ (~i~~0 ~~r~~ ~~~l-~-11~ ~~~Q
Part 2 - Test particulars
a Duct static pressure reading 9QFt~q~ ~ middot~~~1 ~~
b Manufacturer and type of liow measuring d vice (-~~~cJ~Y-9Q7EYg c Range of measurement of now measuring device QtP)OQ~(e~~~0I~~~~1~I~ ~~~~~~W~
d Reading of flm measurin o device pmiddot IFROM RIO)ftscag ~
I (DERlVED [ROM CHART SUPPUED WITH RIG US 0 ud)1e Interpreted air flow leakage rate ~(~~~f~~~ (~l~~~~~~~~~~~~~~~~~I
f Duration ~~~~~norn~allY l~ lnil1Ut~~d~~~ it1~ W~ Date of test ~(lITled ut by Wltll s ed by ~ ~
(~lJ MIJLrr) (Si~rrfltJUYJ
Printed Name 1~g0f~ Printed Name ~~Y~9~ and Company 7jl~~~~~( UJd CompanY AB COII$Itallt8
Width and depth or diameter
Periphery ength Area
millimetreS millimetres metre qL1are metre
800 x 750 3100 1755 5440
600 x 650 2500 557 1193
300 x 300 1200 120 144
305 din 958 700 670
250 dia 785 450 353
TOTAL 8000
53
DW154 Specijilarion for Plastics Ductwork
pA XB
Guida ce No es For he ransport Handling and
Storage of uctwork
avoid damage to adjacent duct panels In somc ca es particularly on con acts calling f r repetitive sizes the use of timber jigs and spacers may be justified Where reduced bulk and greater protection are major factor such as consignments for export transporting ductwork in L shape sections may justify the increa ed ite as embly co ts
It is recommended that before a contract is finalised that consideration is given to the subject of site acces material handling and storage as tbcy havgt a strong influence on the cost efficiency of the overall activity of ductwOlk installation
B3 Handling To minilnise th risk of damage duct sections should be clearly identified and deliveries to site should be closely linked to the installation programme so as to avoid accumulation of
B1 Storage and Handling of Ra Material Material should be stored in suitably designed racking out of direct unJight Where possible the e racks should be metal to earth Edges of cut she t may be harp and protective gloves are advised Wearing teel toe-capped boots is recommended Most pIa tic sheet is manufactured with smootb mfaces andor is suppLied with protective coating Care must be taken to prevent accidental lippag of stacked materials Beiuoshy good electrical insulators the movement of stock unless earthed will allow the build up of stati All stock shapes are chemically stable at normal temperature Whil t some raw materials used in their manufacture may themselves pre ent a toxic hazard once incorporated into the lOck bape they no long r constitute such a hazard and no dermatitic bazard are known nor are any
unfiJied ductwork and minimise double handling It is important to recognise that ductwork panels joint and corners arc susceptible to damage and care must be taken wheu band ling such material through a site During handling individual item of duct work may be liable to light cross sectional deformation until thev become an integral pan of a completed ductwork system Whilst this may temporarily detract from its intended appearance thi deformation will not have any detrimental effect on the functionality of the finally a semblecl system Installation of duct work and asociated plant items ill illevitably involve manual handUng The responsibi Iiry of employers and employees to a ses the risk of personal injury during mallual handling operations is et out in the HS E publication L23 Guidance on Manual Handling Regulations 1992
environmental problems expected 84 Site storage
B2 fransport Large capacity vehicles with high-sided open or closed-top bodies are tlle mo t suitable for the transport of dllctwork Careful consideration should be given to the
Adequate floor space IDust be provided within tbe building for the site storage of ductvork Such storage shalt make due allowance for thc stOf(ne of ductwork in stacks such that access ~ egt
between them is of sufficient width to pennil the removal of item without interference to
unloading of transport on sit a not all siJes b n fit from the material handlino- and access facilities that exi [ in a manufacturing workshop such as crane- fork-lifts or loading bay Site handJiog facilities along with
adjoining sta ks Ductvork components should be positioned so a to avoid crushing Ductwork of small panel size may be stored horizontally however care should be exercised to ensure that tack sizes are limited 10 within
ehicular acce s restrictions may itilluence the type and ize of transport to be uWised
engtlls of ductwork should be positioned 0
the tmctural strength of the duct sections to prevent distortion of the lower sections within the stack
as to avoid crushing Lengths Witll projections such as branches and bends i1anges girths damper quadrauL should be loaded so as to
54
DW154 S1tciic(ltioll for Plastics Ductwork
85 Internal cleanliness of new ductwork The site storage of ductwork introduces the important cODsideration of maintaining the internal cleanliness of the ductwork R feren e should be made to HVCA documentshybull DWffM2 Guide to Good Practice - internal
Cleanliness of New Ductwork Installations If the above conditioDs can not be satisfied consideration should be given by tJle designer to amending the specification to include for Po t Installation Cleaning as covered by tJ1C HVCA documentshybull TRJ17 Guide to Good Practic - Cleanliness
of Ventilation Systems
APPE DIXC
Fi e Retardant inishes C1 Improvement in the fire retardancy of plastic
ducts can be achieved to varying degrees and is wholly dependent llPOll the surface coating laminating resin selected and construction specification adopted In some instances smoke emission is coILSidered equaUy with other speci fication requirernen ts of the materials resistance to ignition and bumjng It is therefore important for design rs to establ ish the clients and officers detailed requirements and not rely on a tbird party interpretation of fire resisting or fire retardant Where possible the specification should refer dir etly to compliance with a British or European Standard identifying the specific sections applicable There are various types of resin and mat rcLnforcements that can achieve a Class 1 surface spread of flame ratin o when tested according to BS476 Part 7 (1987) This test puts materials illto Class I - 4 in descending order of perfoDllance according to the rat and extent of flame spread over their surfac under standard beating conditions Materials should also be tested for flre propagarion to BS476 Part 6 (1989) Tbi tesr measures the amount and rate of heat evolved by the material when subjected to standard heating
conditions Test results are given as an index of Perfonnance (i) whicb is based on three sub indices (iJ (i1) (h) The higher the value of the Index of Performance (i) the greater is the material s contribution to fire growth The higher the value of the sub-index 0) rhe greater the ease of ignition aod flame spread The highest product performance classification as defined in Approved Document B of the Building Regulations is Class O This is acLlieved if a material surface of a composite ploduct i~ either a) composed throughout of materials of
limited combustibility or b) a Class I material which has a tlre
propagation index (i) of not more than 12 and sub-index (i l ) of nor more than 6
01 J Class 0 is not a cla$sif1cation identified in any British Standard test
There are resin system reported to be classified to Class O when tested to BS476 Pcl1S 6 and 7 however designers need to ensure that such sysrems can be applied to their proposed design In propriety resinmat system available the fabrication techniques and COITect application are critical to the integrity of the reinforcing and clas ificatiol1 For example in some systems the u e of a non-fire retardant gelcont on a fire retardant substrate would reduce the classification For further information see HVCA publication DW144 Appendix D
55
DW154 SplCijiClIliol1 for Plastics Ductwork
x Guidance otes For nspectmiddoton Servicing a d
Clean-ng Access Openings
D1 GE ERAL This appendix highlight in ummary fOI111
the acce considerations that hould be made by the design r iD terms of inspection servicing and cleaning Having considered the seop and the design of the dUCI work system relative to the guidelines outlined below the designer should clearly indicate which levels of acces should be incorporated into the manufacture of a new duct work system (See Table 14 and Note I b low it
D2 DESIGN CONSIDERATIONS
D21 In ptction and servicing requireshyments are set out in Section 15 of Lhis specification
D22 Cleaning requirements are set out in the HVCA pubUcation TRl7 Guide to Good Practice Clean Lines of Ventilation Systems and the guide tates The precise location ize and
type of access would be dependent on the type of ductwork cleaning inspection and te ting metbods to b adopted Care protection and standards of cleanliness prior LO cOlllmisionin o
are set out in th AV A publication DWITM2 Guide to Good Practice Internal Cleanliness of New Ductwork Installations and th guide state Wh re specific limits of cleanliness are required ductwork sball be cleaned after installation by a spcialist cleaning contractor It will b in the interests of tht desioner botb financially and practically to cunsider employing a specialist c1eauing contractor at tbe
outset of a contract to internally clean newly installed ductwork prior to bandover This approach would reali e the following benefit shyi) Tb actual numb r of cleaning
access panels could be detennined to suit the method of cleaning to be adopted (This may be 1 s than the maximum requiremen listed under Lev 13 of Table 14)
ii) Clear directions could b given to the ductwork contractor as to tJle size and location of cleaning access panels that are required to be fitted during the mauushyfaclunng pro s
iii) The specialist cleaning operation prior to commi ioning vould enable the cleaning contractor to verify the practical acee requirement for the future cleaning operation associated -vitb a regular maintenance programme
iv) A specialist cleaning operation prior to commissioning would allow the designer to omit from the speeilicatiolJ the DWrrM2 requirem nt for factory sealing protection wipe downs and capping-off
v) Specialist Ieall ill 0 to the measurable standard defin d in TR17 will allow an objective definition of cleanline to be achieved
Car ful consideration must be gIven by the designer to the practl aJ problems associated witb the manufacture and fitting of suitably si Led access panel on small cross section duct and on the circular faces of rouod and flat oval ducts in particular
D23 Special con ideration must be given by the de igner to the practical problems associated with gaining personnel access to heavily congested ceiling areas and multi-la red du twork systems This approach would avoid
56
DW154 Spfciication for Plastics Ductwork
the possibility of access panels being D3 ACCESS 0 IN-LINE EQUIPMENT incorporated into a ductwork system at the This appendix unly covers acc il1spection manufacturing stage that were later found in through the ductwork body adjacent to an item practice to be inaccessible for either ervicing of in-line equipment and not openings in the or cleaning activities equipment itself
able 14 Acce requirements for inspection servicing and cleaning
HVCA PUBLICATIO REFE NeE (uidtgt 10 Gund Prartict
Adjace t OW144 Cleanliness orVcnlillltio S~lcr~ fRjJ7
in-line LeyeJ 1 Level 2 Level 3 ite sequipment pcdionSen lcin~ Section d C1eaniJl( SUn(O)lnspc lion Palle ltk~m_n
2011 (minimum OiL Jubje-ct to duct ~zel (ft~ -Panels
Control Da pcrs One (inspection) 203 One 300 mm x 200 mm Both sid Fire Dampers One (sCTjdJl~) 20211 One 300 0101 x 200 mm One side HeatingCooling Coils One (inspedion) 20213 One 300 mm x 200 mm (lIpstream) Both sides Attenuators (rectangular) None required One 300 mm x 200 mm (downstream) Both sides Attenuators (circular) one retluired One 300 mm x 200 mm (downstream) One side Filter Sections One (inspection) 20212 one required Uoth sides Air Turn Vanes None requjred None required Both sides Changes of Direction None required one required One side In-Duct FansDevices One (inspection) 20213 None required Both sides l
1 In the absence of any indication by the designer only Level ) access will be jncorporated into a new ductwork system
2 Tbe panel izes associated with Lev lis I and 3 acee s ar e middottablished by reference to Section 20 of DW144 and Section 2 ofTRll7 respectively
57
DW154 Speclfifatio for Plastics Ductwork
pA XE
B-bliography Included in this Bibliography are technical pUblications which may be of interest (0 ductwork designers fabricators and erectors and to tho e in the heating ventilatlng air conditioning industries generally nquiric should be made of the relevant organisation at the address quoted Since its publication other addresse contained within 0V154 mav have changed and some pubJicalions may have been superseded
HEATING AND VENTILATING CONTRACTORS ASSOCIATION
4 Palace Court London W2 4JG Telephone 020-7229 2488 Fax 020-7727 9268
Orders fo FlY A Publications Old Matlsion House Eamont Bridge Penrith Cumbria CA 10 2BX (Telephone 01768 864771 Fax 01768 86718) Email hvcapoblicationshvwelfarecouk DWn 44 pe ilicatiun for sheet mctal duclwork (Iow- mediulllshy
and high-pressure) 1998) DWIl4 A practical guide to dUGI ork I akage te ting
(revised 2000) DWII54 Specification for plastic~ duct rk DW171 Guide to good Practice for kitchen venlibtion system DW191 Guide to good pracuce glass fibre ductwoJk DwrrMI Acceptance cheme for new products - Redangolar cro
joint classification Guide to good pra tice - Internal cleanliness of new ductwork installations Guide to good practice for the design for the Installation of lire and smoke uampers
J 1Other puhlications
HampV safely guide 5th edition JS2 Tool box talks JS5 Weldlng Safety booklet JSI9 afety facts bo klet Fact sheets 1-24 2nd edition JS2J COSHH manual volume 1 Advice on compliance with the
regulations 1521A CO I-rH manual volume 2 Asses mcnt h ets JS23 Ri k management manual TR3 BrazinltT and bronze welding of copper pipework cUld sheet
(I 976) TR5 Welding of carbon steel pipework (1980)
TR6 Guide to Good Practice for Site Pre sure Testing of Pipework (19 0) Guide to good practice cleanliness of ventilation Ylem
CHARTERED IN TITUTlO OF BUILDING SERVICES E G EERS Delta House 222 Balham High Road London SW12 9BS rTelephone 020-8675 5211 Fax 020-8675 5449) CIBSE Guide Volume A Design Data Volume B In tallatiol1 and quipment Data Volume C Reference Data
CommlssioniJIg Codes These Codes eover the preliminary checkS eUing to work and regulation of vanous catcgories 0 plan The Codes give a guide to design implications Series A Air Distnbution Systems Series B Boiler Plant
ri s C Automatic Conlrol ystems Cr1es R Refrigerating Sy terns
Sene iN Water Distribution Systems
Technkal Memonllda TM 4 Design Notes for the Middle East TM bull Design otes for Ductwork TM 13 Minimi iog lhc Risk of egiounaires Disease
Research Reports RROI95 Ventilation system hygiene - A review of published
infomlatioo on lhe occurrence and ffects of Olltamination Rl~02J95 Air-to-air heal rec v ry RR0395 rnfluen e of HV C on smoke detectors
ATlONAL ENI [ERING SPECIFICATION LfMITED Southgatc hamber 3739 Southgate Street Winchester S023 9EH (Telephone 01962 842058 Fax 01962 R(8982) BUfLDING S RVICES RESEARCH AND [ ORMATION ASSOCIATIO Old Bracknell Lane West Bracknell Berkshire RG 12 4AH (Telephone Brackl1eU (01344) 426511 Fax 01344 487 -7 )
Application Guides AGln4 De tglJing Vana~le Volume middotylans for KOOnl
iir Movement AG1I91 Commissioning of V Sylcms in Buildings 11 6194 Fire Dampers
B) 94 cntiJalion or KitcneTls
AG389 The Commls ionin of Air Systems In Buildmgs AH2192 Commissioning of Bern - A ~ode of Practice TN2417 I Fire Dampec il) Ventilating Ducl
BEATING VENTILATING A AIR CONDITION G MA UFACTURERS ASSOCIATIO (HEVAC) HEVAC Henley Road Medmenham Marlow Buck SU 2ER (Telephone 01491 578674 ox 01491 575024 Emoimiddot infofetacouk)
Publicatjons Air Diffusion Guide Guide to Air Handling Unit Leakage Testing Guide to Good Practice Air Handling Unit Real Room Acoustic ~ st Procedure Specification for the ertiiicatioll ofAir Filters Method of Test for Water Rejection PerfOnTlatce of Louvrcs Subjected 1(1
Simulated Rainfall Test Procedure for Acoustic Loo cs Specification 10 Floor GrilJes - Types Performan e and Method ofTest Specification for the Determination of the Collection Efficiency of SilJ1d
Trap Louvre Domestic Mechwlical Vclltllalion Systems with Heal Recovery Fan Application Guid
~an and Ouctwork Installation Guide Guide to Fan Noise and Vibration
pecification of Requirements for JallJral Smoke and Heal Exhausl Ventilators
pecification for Powered Smoke and Heat Exhaust Ventilators
Specification of Requirements for Smoke Curtains Design Gujue of Smoke Ventilation for Single Storey Lodustrilll Building~
Including those with Mezzanine Floor and IIi Racked Storage Warehou es - Issue 3
Guidance for the Design of Smoke entilation YSlem for Covered and Undergrollnd Car Parks - lssue 1
Application of SOloke Control Equipment and Syst m Guid to Good Practice - Isue J
58
DW154 Sp(C~tiifitiol for Plastics Ductwork
BRITISH STANDARDS INSTIT TION Sales Department 101 P ntooviLle Road London NI 9ND (felephone 020-78 1 78801)
CP 413 1973 Ducts for building ervices
SS 476 Fire tes on building matenals and lruc(ure
Part 4 19 4 Non-combustibility lest or materials
Part 6 I Fire propagation lest for materials
Part 7 1993 Surface spread of tlarnJ tesls for materia
Part 20 1987 Fir resistance of elements of construction
Part 21 1987 Fire r sistlUlce of loadbeanng elements of construction
Part 22 1987 Fhe istallceofllon-loadbearing elemcllts ofconsttuclion Part 23 1987 Contribution of componcnts to the fire resistance 0 a
structure
Part 24t987 Fire resi lance of wl1lilation ductl
SS 5588 nan 919 0 Fire Precautions III thc desIgn and OOSlnJ lion of buildings
S 729 1971 Hot dip galvanized oatiugs (or irOIl aod stcel articles
BS 1449 Steel plate sheet and Irip
Pan 11991 Carbon steel plate heel and strip Part 2 1983 Stainless steel plate sheer and strip
and
B middotENJOI49-2 996 BSEN 10149- 1991)
BSEN 10131 1992
BSEN22063 Sprayed metal coarings 1994 Protection of iron and steel by aluminium and zinc against
atmospheric cOlosion Irotectiotl of iron and ste I against corro ion and oxishydation at elevared temperatures
BS 353 1981 Glossary of lerms relnting to thermal insulation
BS ISO 1479 Self-tapplngscrewsandmetallicdri c crew
B -lSO 7049
1994
B 4800 1989 Painl colour for building purposes B 4848 l0 rolled structural steel sections
Part4 1972 Equal and unequal angles BS 5422 1990 Specification for the use of therm illuating matcriulS
SS 5720 1979 ode of practice for mechanical veutilating and air C 11shy
dirionin bull in building
l3S PR 12814-1 Bend resting for plasric welds
SS PR 12814-2 Tensile testing for plastic welds
SS PR 13067 Appro altesting for plastic welds
BS PR EN I 100-] Vi ual in pection ofplaslic welds
SHEET METAL AND AIR CONDITIONING CONTR-CTORS NATIONAL ASSOCIATION INC (SMACNA) Headquarters 420 I Lafayeue Center Drive Chanlilly Virginia 2051-1209
Mailing Address pa Box 221230 Cbantilly Virginilt120 153-1230
Telephone (703) 803-2980 Fax (703) 803-3732
Accepted IJJdustry Pl3Gtice for Industrial Duct Constnlelion 197 ) i-rchitecmral Sheet kwl Manual ([993)
Comractors Guide lor Modification 10 ooslruerion Colllraets 1993 Ducted Eleclric Heat Guide for ir Handling Ssrerns (1994)
En~rgy ollservatioD Guidelines (1984) Energy Recovery Equipment yslClllS (199l
Fibrou GIns Duct onS1ntClion Standards (1992)
Fire Smoke amp Radiation Damper In tall Guide for HVA Syst ms (1992) Guide t leel Stack 1(95)
HVA Air Duct Leakage Test Manual (19 ) HVA COlllmissioning lvlanual (1994)
H A Duct Construction Standards-Metal amp Flexible (1995) Addendum 01 (Nov 1997)
HVA Duct Systems Inspection Guide (1989)
HVA ySlems-Application (1986) nVAC ByternS-DLlct D ign (1990)
HVi Systems-Testing Adjusting amp Balancing (1993)
indoor Air Quality Manual (1993) tcheu quipment Fabrication Guidelmes (1990)
Managers Guide for elding (1993)
Rectangular Industrial Duct Cons1TUction Standards (19 0) Round Industrial Duct oustmction Standards (1977)
Sei mic Restraint Manual (1991) (wl Appendix E 1993) SMACNA Ma le Index ()fTechnical Publications (1995) Tbennoplnstic Duct CPY ) Construction Manual 1994)
DEPARTME OF THE ENVIRO MENT (Publications Centre) H Stationery Oflice 5 Nine Elms Lane London SWS 5DR
MampEJ 011972 Electrical in tallat1011 in buildings ( ew Editiou)
IampE 0319 Healing hot and cold wat r steam and gas losla1lations for buildings
M amp - No4 1970 Central heating and hot and cold ~ ateT in tallations for
dwelling
M amp ENo100 1971 Mechanical ventilation for building~
ASSOCIATION FOR SPECIALIST FIRE PROTECTlO As ociation House 235 Ash Road AJdershot Hampshire GUl2 4DD
Telephone OJ25221322 Fax 0 J252 333901
lublicalioos Fire Ratcd and moke Outlet Ducrwork An Industry Guide t Design and InSlalla lioll
HEALTH AND SAFETY EXEC TIVE Rose Court 2 Southwark Bridge London SEl 9HS Telephone 020-7717 6000
TWJ THE WELD G TlTUTE Abington Hall Abington Cambridge CB16AL Telepbone 0 J223 89162
Publication DatJ Oil w~ldll1g of lhermopla lics
59
DW154 wciiwlioll for Plastics Ductwork
A -=--DIX
Factors
Specific gravity shy pp = 091 approx UPVC = 14 approx
Some miscellaneous conversion factors
To convert
Length Inches to millimetres Feet to metres
Multiply by
2540 03048
To convert
Millimetres to inches Metres to feet
vIultiply by
003937 3281
Area Square inches to square millimetres 6452 Square millimetres to square inches 000155 Square feet to square metres 00929 Square metres to square feet 10764
Volume Cubic feet to cubic metres Cubic feet to litres Gallons (UK) to litres
002832 2831 4546
Cubic metres to cubic feet Litres to cubic feet Litres to gallons (UK)
35315 00353
022
Mass Ounces to grams Pounds to kiJograms Tons to tonnes
2835 04536
1016
Grams to ounces Kilograms to pounds Tonnes to tons
003527 2205
09842
Volume flow Cubic feet per minute to cubic Cubic metres per second to cubic
metres per second 0000472 feet per minute 2119 Cubic feet per mIDute to litres Litres per second to cubic feet
per second 04719 per minute 2119
Motion Feet per minute to metres per second 000508 Metres per second to feet per minute 197
Pressure Inches water gauge to millibars 2491 Inches wateJ- gauge to pascals (Pa) 2491 I Pa = I ewton per square metre = 10-2 millibars
60
Heating and Ventilating Contractors Association Esca House 34 Palace Court London W2 4JG
Tel 020 7313 4900
e-mail contact Itvcaorguk web site wwwhvcaorguk
Fax 020 7727 9268
DW154 Specificatioll for Plastics Ductwork
G - Cross joints and tiffeners
Fig 29 Flange Joint Fig32 Stiffener shy inverted angle
M artiPfCuQkbdd erttpObri) Wl111 RP tlddtlt
_- GRPloliu] lh~
Fig 30 Socket and spigot joint Fig33 Stiffener shy use of former
Fig 31 Stiffener Flat
I Pv FlPP ~ ~lmJaDUA1) d
OMrlQ rrnall 1( tQlS
25 STANDARD COMPONENT DRAWINGS AND ABBREVIATIONS
251 The illustrations in this section not only highlight where applicable geometric limjtations for the de ign and manufacture or ductwork components but also recommend
standard drawing representation terminology and abbreviations for both duetwork components and some of the more commonly used ancillaryplant items
252 Designers and surveyors should note that bills of quantities should provide a full description
3)
---
v
DW154 Spcc(fim(ml for Plastics Ductwork
Fig 34 Linear Thermal Expansion
u c 0 N ro 0)
b 0)
S
sect0
5 oS cl) 0)
~
on ~ ltl
c U
-30 -20 -10 0 10 20 30 40 50 60 70 80 90 TEMPRATURE C
~ V
-
~~c_ ~
~V
V ~
-7 ~
-- ~V ----
v
-6
+14
+12
+10
+8
+6
+4
+2
0
-2
--4
ig 35 Typical Design Stress tor UPVC and P
7
6
r shy 5E
-c E----0 4t) VJ 0)
ci5 0Jl 3
~
0)
Cl
2
1
o
UPVC
1
000
1
1
pp
- r-- shy r----- shy - t--shy I
__0
-30 -20 -10 0 10 20 30 40 50 60 70 80 90 TEMPERATURE C C
Note Figso 14 amp 35 shaded area refers to GRP reinforced duct
32
DW154 Speciicfltirm for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - REC ~NGULAR
Splilt~r Posilion W-mm pliucr
A B c 40]--QOO 1 W - -
601-1000 1 W4 Wf2 -
1001-1800 3 WI W3 W2
FIG DRAWING DETAfiS
tU]36 ATI Straight Duct with socket and spigol joint
rn [037 Straight Duct with flanged joints
[I []38 Straight Duct with flanged joints
rkJ Short Radius Bend
39 Applies to any augl and for duct up to 400 n11n wide
Minimum (I1m31 radills = 100 mm
Medium Radius Bend (a illustrated)
[kJ Applies to any angle
40 Long Radiu Bend Similar but radius = W
Throlll radius = W2 Applies to any angle
- Short Radius Bend with plitlers
I -shy -shy u co - t lt Li--_ 41 t 0 ~ I I I
~ I
L 1W
Minimum waal radius = 100 mm Splitters not required in bend angle less than 45deg
42 QJ1 Square Bend with turning vanes ij
3
DW154 SP(L~ficatioll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - RECTANGULAR
FIG DRAWl G DETADS
43
~
I v
L L Radius Tee with internal deflectors
44
~ Radiussed Twin Bend
45
Imiddot
er Swept Branch
46 U-
Sqoare Tee with Turning Vanes
47
~ f
Breeches Piece
48 0 y l Piece
34
DW154 Specificatioll for Plastics Ductwork
STANDARD COMPONENT RAWINGS - ECTANGULAR
55
54
51
50
53
52
49
FIG
~MX
RAWlNG
DmiddotMAX
EfjMAX
Minimum throat rndius = 100 mm
Rectangular shy Round Transformatioll
Eccentric Taper 225deg max in either plane Spliller are required for angles greater than 225deg and hould bi eet the angle between any side and duct centreline
DETATLS
Angled Offset
OUset Taper Splitters are required for angle greater than 22 0
and shoold bi eet the angl between any side and dUCI centrelinc
Mitred Offset
Concentrk Taper 2250 max in ither plane SpUtters are required for angle greater than 225deg and should bisect the angle between any side and duel c ntreline
Radiussed Offset
35
DW154 Splcilcuthm for Plastics Ductwork
STANDARD COMPONENT DRAWINGS ~ RECTANGU AR
Branch ducl DimCllsions widlh (W) (A)
urnl mm up lO 200 75
300 100 400 125 600 150
Ocr 600 200
FIG DRAWlNG DETAILS
56 poundplusmni~~ Rectan~lar - Flat Oval Transformation
57 [ Square Branch
58 er Angled Branch
Branch dUCI Dimensions wfdth (W) (A)
[- mm mm59 3shy Shoe Branch Up (0 200 75
--shy AIshy + 300 100
400 125
450 MAX 600 150
Over 600 200
Branch duct DimensIOn
rP X width (W) A)
60 - 1--shy _
~ mm mm
Bell Mouth Branch pto 200 75 300 100 t 400 125
600 150 Over 600 200
0=0 61 -
~ Bell Mouth
- shy T 4-5deg M x
--I 1-shy
TJ
62 X I ] I
Tele-scopic Joint I Illustrated with flangeL
X63
SBD Single Bladed Damper
36
---
DW154 Spedicatioll for Plastics Ductwork
STANDARD OMPONENT DRAWINGS - RECTANGULAR
DRAWING DETAILSFIG
64 on-Return DamperNRD shyshy
shyXbull
Multi-Leaf Damper Can be piggoted or flanged oppo cd or parallel blade
Alternative controls areshy
q p [gtshy
J HD65 Hand
~MD otori ed
PO Pneumalic
L-lt
l 13G 66 Blast Gate DamperX X
FireSmoke DampersSleeves
211r Ratinggtshy----
L_-
---
----
r----
Ir-- shy
IL- _-l
2hr
With i tallation frame
67 41 r Rating
4hr
Smoke damper SD
Intumc cent Sleeve L-d
37
DW154 Specijicutiolt for Plastics Ductwork
FIG
68
69
70
71
STANDARD COMPONET DRAWINGS shy REC ANGULAR
DRAVING DETAILS
gtshy Access Openings
AP 6 Access Panel - Rerno able
w [ ~ Access Door - Hinged
I ~le Inspection Cover
le -I reg -lt
~X X Flexible Connection
~ Drop Cheeked Radiussed Twin Bend
U Drop Cheek Bend
I
72 Air Flow SymbolX
38
DW154 Specifim[ioll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - ECTANGULAR
FIG DRAWING DETAILS
73
74
75
76
77
Q
Q
rp---t
~
V- I Ir---I
JL --11
THE ABOVE DETAILS TYPICAL PLENUM
Air Terminal Plenums
Plenum with side connection
Plenum with top connection
Cover plate with connection
Special plenum with connection
elescopic conn ction in direction of air flow
39
DW154 SpecijicotiOll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG
78
79
80
81
DRAWING
-23~---pound3-(MALE) (FEMAJE)
-t=j--_j(--d-shy
--L
~ THROAT RADI S= D AS T NDARD
e ~
THROAT Rjf)lU = D A MU)
DETAILS
Straight Duct With male and female connectors
Straight Duct With flange joint and slip joint
Bend MouldedIFormed Applies to any angle ego 30deg45deg60deg90deg Medium radius bend as illustrated Long radius similar but throat radius 0
Segmented Bend 90deg four section minjmum as illustrated
Other Angles 60deg = 3 sections 45deg = 3 sections 30deg = 2 sections
I
i
40 shy
DW154 Speciicafinll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG DRAWING DETAlLS
82 Segmented Twin Bend Radius = D2 max
May also be fabricated from tube
83 Equal Tee MouldedIFormed
84 -~ 1in Bend MouldedIFormed
85 Taper Concentric 1 0 as iUu trated Eccentric 30deg iJJcLuded angle
86 Short Taper
41
DW154 SpcUicatol1 for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG DRAWING DETAILS
87 30 max Offset
Angle Branch
Bran h dUCI Dimcnsions dia (D) lA)
Shoe Branch mm mm 88 Cl
Off rectanguJur Up 10 200 75 lOO 10 400 125
- 00 150 Over 600 200
Bl1IllCh duct DimenlOns din (D) (A
~-$a-Conical Branch mm mm
89 Also acceptable with Up 10 200 r
full conical surface 300 10
400 125
END VrE -shy 600 150 Over 600 200
90
m 75
100 12 150 200
mm Up to 200
_ 300 400
600 Over 600
iUtred Branch
Shoe Branch
J-L----U ~ Bell oulh Branch
ENDV1EW
93
92
91
42
DW154 Specificatiol for Plastics Ductwork
STANDARD OMPONENT DRAWINGS - CIRCULAR
FIG
94
DRAW G
I
~ 30deg 090deg
Breeches Piece
DETAILS
95 amp-----~ Blank End
~-----p Multi-Leaf Damper Can be piggolcd or fianged opposed or parallel blade
Alternative controls areshyri=-+- L-T~
I
---
LT~
I r- -
-+1
J HO Hand96
bMD Molori cd
PD Pneumatic
tl-shy bull
Single Bladed Damper 97 ~ saD
on-Return Damper Vertical application only 98 m~D
43
DW154 Sf1tcificatioll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG
99
100
101
102
DRAWING
$ I-
2hr
1 4hr
SD
~v I I
CO TINENTAL COWL
DETAILS
Iris Damper
Fi reS moke Dam persSleeves
2hr Ratillg
With installation frame
4br Rating
Smoke damper
Intumescent Sleeve
Access Openings
Access panel - removable
Access door shy hinged
fnspection cover
Discharge Continental Cowl
44
DW154 Sp(Cii(ltJll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
DRAWINGltIC DETAns
-
I
I
~
I I I High Velocity Discharge Terminal 103 I
I
I I
J I I 1 ~--
Offset Stack Discbarge Terminal 104 1
~ I e --(-
I
N
I
I
I~
I I Vertical Oischarge with Weather Cowl 105 I
--1--1 I
I
GAPI I
RTl AL DISC) lARGE WITH W ATIIER COWL
45
DW154 SpecUicatoll for Plastics Ductwork
STANDARD COMPONE T DRAWINGS - PLA TEQUIPMENTIMISCELLANEOU
FIG DRAWING DETAILS
106 ~~~ Rectangular Attenuator
107 ~- Circular Attenuator
108
~ Beod Attenuator
109 J ~(f) Heating Coil
110 J ftte Cooling Coil
III Jc[ Electric Heating Coil
112 X F
Humidifier
113 [H XX Axial Fan
114 ~fB1famp Noo-standard Ductwork Cross hntchillg (of any separate type) indicates by reference to a key any non DVil54 ductwork system
115 2llIIIIJIIIIIll Flexible Ductwork
46
DW154 SJeCUicll(iol1 for Plastics Ductwork
TABLE 12 - STANDARD ABBREVIAT ONS
ABBREVIATION FLL
AD Acces Door
AFF Axial Flow Fan
AHU Air Handling nit
All Aluminium
AP Acess Panel
AT Attenuator
AV Air enninal Unit
BE 81ank nd
BQ Blast ate Damper
CC Cooling Coil
CF Centrifugal Fan
CTA Cross alk Attenuator
CVU Constant Volume Unit
DP Drain Point
EEC Electric Heating Coil
El Expansion Joint
FAl Fresh Air Inlet
FA From Above
FB From Belo
fBPP Fabric Backed Polypropyl-ne Sheet
Flexle Flexible Connection
lexfD Flexible Du t
C False Ceiling CO an oil Unit
fD Fire Damper
FFL Finished Floor Level
FJ Flanged Joint
FOAM Rigid Polyurethane Self xtinguishing Foam
FOB Flat on Bottom
FOT Flat on Top
GAM Galvanised after ManufacttrJc
GRP Glass Reinforced Plastic
GSS Galvanised Sheet Steel
HC Heating oil
HD and controlled Damper
HH Hand Hole
HL High Level
HVD High Velocity Discharge
IC Inspection Cover
ID lri Damper
IFS Intumescent Fircleevc
47
DW154 Specification for Plastics Ductwork
TABLE 12 - STANDAR ABBREVIATION CONTINUED
ABBREVIATION
IU
L
tv1D
MS
NRD NTS
OBO
OE
PHD
PD
PP
PP
PRD
PVC
RFC
RSC
R
SBO
SO
S1 TST
SSL
TA
TB
TO TJ
TP
TV
TV
OS
UPVC
S
V
VAV
50 RSA
FULL
Induction Unit
Low Level
Motor controlled Damper
Mjld Steel
on Return Damper
at to cale
Opposed Blade Damper
Open End
Parallel Blade Damper
Pneumatic controlled Damper
Polypropylene
Self xtinguishing Polypropylene
Pressure Relief Damper
Polyvinyl Chloride
Rolled Form Chamlel
Rolled Steel Channel
R fUnit
Singl Blade Damper
Smoke Damper
Slip Joint
Stainl t el
tructural Slab Level
To Ab vc
To Blow
Top Down (In Direction of Flow)
Telescopic Joint
Test Point
TU111iog Vane
Top Up (In Direction of Flo )
Voles Otherwise Stated
Unpl3sticisecl Polyvinyl Chloride
Underside
Ultra Violet Light
Variable Air Volume
Rolled Steel Angle (Vith Size)
48
DW154 SJeriiflllioll for Plastics Ductwork
A2 DUCT PRESSUREAPPE DXA Ductwork con truct d to DWIl54 will bebullbullbullbullbullbullbullbullbullbullbullbullbullbull
Air Leakage From Ductwork To be read in conjunction with DW143 A practical guide to Ductwork Leakage Testing
CAUTION As highlighted ill both this docul1lenr and DW14 I lot ellough emphasis can be placed 01 the fact that except for high pressure class C the much more stringent ductwork constructional standard brolght about b the general acceptance of DW154 have irtlally negated the requirement for leakage-testing It is essential lO realise lhat except where it is mandatory this doclllllelll is nOl an endors ~lIlent of the rourine testing of ducts bllt purely a guide to outline the procedures for cononnity with the air leakage limits ill Table l Where the specified methods of assembly and
A3sealing of dlcls are u ed a vi ual inspection wil ordinarily sl~fll e for ver(iatioll of a well engineered and a ceptahfy airtight COl1strucrioll WHERE NOT MANDATORY DUCT LEAKAGE TESTING IS GENERALLY AN UNJUSTIFIED AND SUBSTANTIAL EXPENSE
A1 INTRODUCTION L akage from ducted air distribution systems is an Lmportant consideration in the design and operation of ventilatjon and air conditioning middotystems A ductviork t)ystem tbat ba limited air leakag within defiucd limits wiH cnsUft
that tile design characteristics of the sytem can be maintained It wilJ also ensure that energy and operatLonal cosb are maintained at optimum levels DucLwork constlucted and Ulstalled in accordance with DW154 should minimise a level of air leakage that it) appropriate to tll operating static air pre sur in tile system
A4However it is recouuised that tbe environment in wtJich middotystems are installed is not always conducive to achieving a predictable level of quality in term of system ajr leakage and it is therefore accepted that designer may sometimes require tlle ystem to be tested in part or in total It should be ecogni ed that the testing of duct systems add a ignificant cost to the installation and incur some extra tjm within the programme (Se 47 and 64 re mandatory te-sting)
manufactured to a structural standard that is compatible with the system operating pressure There are three classes of duct con truction to eorre pond with the three pre ure clas meations Class A Lo pressure ducts suita le for a maximum positive operating pressure of 500 Pascal and a maximum negative pressure of -500 Pascals Class B IVledium pressure ductmiddot suitable for a rnaxilnuJJl positive operafjn o pressure of 1000 Pascals and a maxllnum negative pre sure of -750 Pa cal Class C High pre sure ducts suitable for a maximum po ilive operating pressur of 2000 Pa cals and a maximum negativ pres ur of -750 Paltcals
LEAKAGE FROM DUCTWORK Leakao-e front pia tic air ducts occur at the joint~ and is therefore proportional to the total surface area orthe du twork in th system Tb level of leakage i imilarly related to tIle air pres ure in th du t system and whilst there LS n precis formula for calculating the level of air los it i generally accepted that leakage will increase in proportjon to pressure to rbe pOvver of 065 The effect of air leakage from high pressure velocit ductwork is critical tn terms of system perfomlan dege energy consumption and the risk of high frequency noise as ociated with leakage These problems are le critical with medium pressure 10 ity systems but should be con idered Low pres mevelocity ducts present the lowe~t
ri k in tenn of tbe effect of leakage on the operation of the s stern
SYSTEM LEAKAGE LOSS As there i no di ct relatLonship between th volume of air conv yed and the surface area f the ductwork sy tern required to match the building configuratmn it is difficult to express air leakage a a percentage of total air volume Similarly the operating pressure will vary throughollt lh 3 system and a leakage is related to pre me the calculations ar comple However it is generally ac epted tbat in typical good quaJjty systems the leakage from
49
DW154 Specificatioll for Plastics Ductwork
each class of duct llnd r operating condition will be io the region of CIa S A low pressure 6 Clas B medium pres un 3 Clas C high pressure 2
A5 SPECIFYING AIR LEAKAGE TESTING Re peeting both the co -t and programme implications a sociated with te ling du 1 for leakage the designer may for example indicate that a particular system is te ted as follow
a) High pressure ducts - all tested b) Medium pr ssure duets - 10 of the
ductwork shall be s eet d at random and tested
c) Low pre sure - unte ed In any case where a random te t i elected for medium pre sure ductmiddot the followin c1au~e is suggested for inclusion by the de ign r
The designer hall elect at random a maxirnwlI of 10 of the dUCl system to bt tested for air leakage The duct hall be tested af the pressure recommended in Table J3 for the assifi atiol for the ectiol1 of the ductwork that is to be tested The tests shall be carried Ollt as the work proceeds and prior to the application of thermal insulation In the event of test failure of the randomlY selected section the designer shall have The right to select two La1her e tiolls at random for resting Where succes ive failures are identified there shall be a Tight to require rhl COl11raCWr 10 apply remedial attention to the complete ductwork system Th contractor shall provide documented eviden e of the calculalions used to arrive (1
the allowable 10 I for the section to be tested and the client or his agent shall willess and sign the results of the test
able 13 Air leakage rates
Maximum leakage of duct work Static
prcssUft Low-pressure edium-prc-sure I Iigh-prebull me diJfercntial Class A Class B Class C
1 2 J 4 Pa Litres per second per quare metre of surface area 100 054 018 ZOO 084 028 300 110 037 400 132 044 500 153 051 600 058 019 700 064 021 800 069 023 900 075 025
1000 080 027 1100 1200 1300 1400 1500
029 030 032 033 035
1600 1700 1800 1900 2000
036 038 039 040 042
Note Recommend d mean test presures are highlighted iD bold type with the actual selection being left to tll test operator
50
DW154 Sfeeiieaioll for Plastics Ductwork
A9
A10
and air leakage classification for the y em under test
DESIGNERS CALCULATIONS The designer can middotaJculate with reasonable accuracy the predicted total loss from a ystem by
a) Calculating the operatin presure in each ection of the sy tern
b) Calculating the surface area of the ductwork in each correspondin pre lire s ction
c) Calulating the allowabl~ los at the operating pressure for each ection of the system (see table 13 for allowable leakage figures)
VARIABLE PRESSUR S IN SYSTEMS De igner can achieve significant co t saving by matchina operating pressures throughout the system to constmctional standard and appropriate air leakage testing eO the practice of specifying construction tandards for whole duct sy tems based on fan discharge pre sure may incur unnece sary costs on a project For example ome large sy terns ould well be classiC ed for I akage limits as follows
Plant room risers CJas C Main floor distriblltJou CIa B Low pre sure outlets Cla A
A6 SPECIAL CASES There may be ~itLlations on a project where circumstance dictate thal pecial consideration be given to containing air loss s eg a long mn of duclwork may incur a di -proportjonate level of air 10 s In ca es such as thi example the designer can specify an improved tandard of airtighmess ie 80 of alJo~able 10 s for la B Ju ts The designer sbould not specif a CIa C t sI at CIa s C pressure for a CIa s B ducl
A7 SUGG S ED RANGE OF TES ING
A8 TESTING OF PLANT ITEMS Items of inline pJant (eg Fig 106 to 115) will not normaUy be included in an air I akage test The dllctwork contractor may indud such itelllS in tbe te t jf rh quipm ot has a certificate of COnfOlnlity for Ihe pres ure clas
bull High pressure duct bull Medium pre sure ducts bull Low pre sur ducts bull Exposed extract syst ID bull Ceiling void extract
systems bull Secondary ducts from
VAV or fan coil units bull Flexjble duct bull Final connections and
branches to grille and diffusers
100 test See A5 Untested UDt sted
Untested
Untested Untested
Untested
SI
i
DW154 SJecijicafion for Plastics Ductwork
ig 116 Permitted leakage at various pressures
Leakage in litres per second per square metre duct surface area
Vgt
o ltgt 0 ltgt N
ltgt Cgt
0 0 cc
0 0
~
g =
g ~
c 0
J
ltgt 0 I
~ ] tn
ltgt ltgt
In ol
~ 0 ~ 8 ~
~
c ltgt ltgt
~ CJ
~ ~ ~ ~ 8
0shyij
~ ~ ~ t
ltgt ltgt 00
l
~
~ Q
c C
~ rshy
e ltgt
I 1
I Cgt ltgtv
c Co ~
~~ ~ 10
I
0 Cgt
fJshyq 410 ) 1 ltgt
ltgt N
~ shy ltgt ltgt
~ I 1
c
52
DW154 Specificatio for Plastics Ductwork
Example of a completed test sheet Test No
General
Name of job N~ jC43Pt(r2lef Building Repound ~(~~0
Part 1 - Physical details
a Section of duct work to be tested ~(diffPIfff~el1f3rd Floor
b Drawing Number g91~~ c ssure aSSJ L atlOn V~Jl~IRfYgtg~~lPre Cl T Class C
d Test static pressure -(9 raErq~ ~~~~-~~J~~~ ~~ ~~~~ll
Leakaoe factor 9~-tre3$ecMz I OM REFTOTABLE 13)e b bullbullbullbullbullbullbull
f Surface area of duct under test Q~tJJItetre$ CPROMCALCU TIO BELOW)bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull ampampamp bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull
g ]Vlaxi mum permitted leakage -~ (~i~~0 ~~r~~ ~~~l-~-11~ ~~~Q
Part 2 - Test particulars
a Duct static pressure reading 9QFt~q~ ~ middot~~~1 ~~
b Manufacturer and type of liow measuring d vice (-~~~cJ~Y-9Q7EYg c Range of measurement of now measuring device QtP)OQ~(e~~~0I~~~~1~I~ ~~~~~~W~
d Reading of flm measurin o device pmiddot IFROM RIO)ftscag ~
I (DERlVED [ROM CHART SUPPUED WITH RIG US 0 ud)1e Interpreted air flow leakage rate ~(~~~f~~~ (~l~~~~~~~~~~~~~~~~~I
f Duration ~~~~~norn~allY l~ lnil1Ut~~d~~~ it1~ W~ Date of test ~(lITled ut by Wltll s ed by ~ ~
(~lJ MIJLrr) (Si~rrfltJUYJ
Printed Name 1~g0f~ Printed Name ~~Y~9~ and Company 7jl~~~~~( UJd CompanY AB COII$Itallt8
Width and depth or diameter
Periphery ength Area
millimetreS millimetres metre qL1are metre
800 x 750 3100 1755 5440
600 x 650 2500 557 1193
300 x 300 1200 120 144
305 din 958 700 670
250 dia 785 450 353
TOTAL 8000
53
DW154 Specijilarion for Plastics Ductwork
pA XB
Guida ce No es For he ransport Handling and
Storage of uctwork
avoid damage to adjacent duct panels In somc ca es particularly on con acts calling f r repetitive sizes the use of timber jigs and spacers may be justified Where reduced bulk and greater protection are major factor such as consignments for export transporting ductwork in L shape sections may justify the increa ed ite as embly co ts
It is recommended that before a contract is finalised that consideration is given to the subject of site acces material handling and storage as tbcy havgt a strong influence on the cost efficiency of the overall activity of ductwOlk installation
B3 Handling To minilnise th risk of damage duct sections should be clearly identified and deliveries to site should be closely linked to the installation programme so as to avoid accumulation of
B1 Storage and Handling of Ra Material Material should be stored in suitably designed racking out of direct unJight Where possible the e racks should be metal to earth Edges of cut she t may be harp and protective gloves are advised Wearing teel toe-capped boots is recommended Most pIa tic sheet is manufactured with smootb mfaces andor is suppLied with protective coating Care must be taken to prevent accidental lippag of stacked materials Beiuoshy good electrical insulators the movement of stock unless earthed will allow the build up of stati All stock shapes are chemically stable at normal temperature Whil t some raw materials used in their manufacture may themselves pre ent a toxic hazard once incorporated into the lOck bape they no long r constitute such a hazard and no dermatitic bazard are known nor are any
unfiJied ductwork and minimise double handling It is important to recognise that ductwork panels joint and corners arc susceptible to damage and care must be taken wheu band ling such material through a site During handling individual item of duct work may be liable to light cross sectional deformation until thev become an integral pan of a completed ductwork system Whilst this may temporarily detract from its intended appearance thi deformation will not have any detrimental effect on the functionality of the finally a semblecl system Installation of duct work and asociated plant items ill illevitably involve manual handUng The responsibi Iiry of employers and employees to a ses the risk of personal injury during mallual handling operations is et out in the HS E publication L23 Guidance on Manual Handling Regulations 1992
environmental problems expected 84 Site storage
B2 fransport Large capacity vehicles with high-sided open or closed-top bodies are tlle mo t suitable for the transport of dllctwork Careful consideration should be given to the
Adequate floor space IDust be provided within tbe building for the site storage of ductvork Such storage shalt make due allowance for thc stOf(ne of ductwork in stacks such that access ~ egt
between them is of sufficient width to pennil the removal of item without interference to
unloading of transport on sit a not all siJes b n fit from the material handlino- and access facilities that exi [ in a manufacturing workshop such as crane- fork-lifts or loading bay Site handJiog facilities along with
adjoining sta ks Ductvork components should be positioned so a to avoid crushing Ductwork of small panel size may be stored horizontally however care should be exercised to ensure that tack sizes are limited 10 within
ehicular acce s restrictions may itilluence the type and ize of transport to be uWised
engtlls of ductwork should be positioned 0
the tmctural strength of the duct sections to prevent distortion of the lower sections within the stack
as to avoid crushing Lengths Witll projections such as branches and bends i1anges girths damper quadrauL should be loaded so as to
54
DW154 S1tciic(ltioll for Plastics Ductwork
85 Internal cleanliness of new ductwork The site storage of ductwork introduces the important cODsideration of maintaining the internal cleanliness of the ductwork R feren e should be made to HVCA documentshybull DWffM2 Guide to Good Practice - internal
Cleanliness of New Ductwork Installations If the above conditioDs can not be satisfied consideration should be given by tJle designer to amending the specification to include for Po t Installation Cleaning as covered by tJ1C HVCA documentshybull TRJ17 Guide to Good Practic - Cleanliness
of Ventilation Systems
APPE DIXC
Fi e Retardant inishes C1 Improvement in the fire retardancy of plastic
ducts can be achieved to varying degrees and is wholly dependent llPOll the surface coating laminating resin selected and construction specification adopted In some instances smoke emission is coILSidered equaUy with other speci fication requirernen ts of the materials resistance to ignition and bumjng It is therefore important for design rs to establ ish the clients and officers detailed requirements and not rely on a tbird party interpretation of fire resisting or fire retardant Where possible the specification should refer dir etly to compliance with a British or European Standard identifying the specific sections applicable There are various types of resin and mat rcLnforcements that can achieve a Class 1 surface spread of flame ratin o when tested according to BS476 Part 7 (1987) This test puts materials illto Class I - 4 in descending order of perfoDllance according to the rat and extent of flame spread over their surfac under standard beating conditions Materials should also be tested for flre propagarion to BS476 Part 6 (1989) Tbi tesr measures the amount and rate of heat evolved by the material when subjected to standard heating
conditions Test results are given as an index of Perfonnance (i) whicb is based on three sub indices (iJ (i1) (h) The higher the value of the Index of Performance (i) the greater is the material s contribution to fire growth The higher the value of the sub-index 0) rhe greater the ease of ignition aod flame spread The highest product performance classification as defined in Approved Document B of the Building Regulations is Class O This is acLlieved if a material surface of a composite ploduct i~ either a) composed throughout of materials of
limited combustibility or b) a Class I material which has a tlre
propagation index (i) of not more than 12 and sub-index (i l ) of nor more than 6
01 J Class 0 is not a cla$sif1cation identified in any British Standard test
There are resin system reported to be classified to Class O when tested to BS476 Pcl1S 6 and 7 however designers need to ensure that such sysrems can be applied to their proposed design In propriety resinmat system available the fabrication techniques and COITect application are critical to the integrity of the reinforcing and clas ificatiol1 For example in some systems the u e of a non-fire retardant gelcont on a fire retardant substrate would reduce the classification For further information see HVCA publication DW144 Appendix D
55
DW154 SplCijiClIliol1 for Plastics Ductwork
x Guidance otes For nspectmiddoton Servicing a d
Clean-ng Access Openings
D1 GE ERAL This appendix highlight in ummary fOI111
the acce considerations that hould be made by the design r iD terms of inspection servicing and cleaning Having considered the seop and the design of the dUCI work system relative to the guidelines outlined below the designer should clearly indicate which levels of acces should be incorporated into the manufacture of a new duct work system (See Table 14 and Note I b low it
D2 DESIGN CONSIDERATIONS
D21 In ptction and servicing requireshyments are set out in Section 15 of Lhis specification
D22 Cleaning requirements are set out in the HVCA pubUcation TRl7 Guide to Good Practice Clean Lines of Ventilation Systems and the guide tates The precise location ize and
type of access would be dependent on the type of ductwork cleaning inspection and te ting metbods to b adopted Care protection and standards of cleanliness prior LO cOlllmisionin o
are set out in th AV A publication DWITM2 Guide to Good Practice Internal Cleanliness of New Ductwork Installations and th guide state Wh re specific limits of cleanliness are required ductwork sball be cleaned after installation by a spcialist cleaning contractor It will b in the interests of tht desioner botb financially and practically to cunsider employing a specialist c1eauing contractor at tbe
outset of a contract to internally clean newly installed ductwork prior to bandover This approach would reali e the following benefit shyi) Tb actual numb r of cleaning
access panels could be detennined to suit the method of cleaning to be adopted (This may be 1 s than the maximum requiremen listed under Lev 13 of Table 14)
ii) Clear directions could b given to the ductwork contractor as to tJle size and location of cleaning access panels that are required to be fitted during the mauushyfaclunng pro s
iii) The specialist cleaning operation prior to commi ioning vould enable the cleaning contractor to verify the practical acee requirement for the future cleaning operation associated -vitb a regular maintenance programme
iv) A specialist cleaning operation prior to commissioning would allow the designer to omit from the speeilicatiolJ the DWrrM2 requirem nt for factory sealing protection wipe downs and capping-off
v) Specialist Ieall ill 0 to the measurable standard defin d in TR17 will allow an objective definition of cleanline to be achieved
Car ful consideration must be gIven by the designer to the practl aJ problems associated witb the manufacture and fitting of suitably si Led access panel on small cross section duct and on the circular faces of rouod and flat oval ducts in particular
D23 Special con ideration must be given by the de igner to the practical problems associated with gaining personnel access to heavily congested ceiling areas and multi-la red du twork systems This approach would avoid
56
DW154 Spfciication for Plastics Ductwork
the possibility of access panels being D3 ACCESS 0 IN-LINE EQUIPMENT incorporated into a ductwork system at the This appendix unly covers acc il1spection manufacturing stage that were later found in through the ductwork body adjacent to an item practice to be inaccessible for either ervicing of in-line equipment and not openings in the or cleaning activities equipment itself
able 14 Acce requirements for inspection servicing and cleaning
HVCA PUBLICATIO REFE NeE (uidtgt 10 Gund Prartict
Adjace t OW144 Cleanliness orVcnlillltio S~lcr~ fRjJ7
in-line LeyeJ 1 Level 2 Level 3 ite sequipment pcdionSen lcin~ Section d C1eaniJl( SUn(O)lnspc lion Palle ltk~m_n
2011 (minimum OiL Jubje-ct to duct ~zel (ft~ -Panels
Control Da pcrs One (inspection) 203 One 300 mm x 200 mm Both sid Fire Dampers One (sCTjdJl~) 20211 One 300 0101 x 200 mm One side HeatingCooling Coils One (inspedion) 20213 One 300 mm x 200 mm (lIpstream) Both sides Attenuators (rectangular) None required One 300 mm x 200 mm (downstream) Both sides Attenuators (circular) one retluired One 300 mm x 200 mm (downstream) One side Filter Sections One (inspection) 20212 one required Uoth sides Air Turn Vanes None requjred None required Both sides Changes of Direction None required one required One side In-Duct FansDevices One (inspection) 20213 None required Both sides l
1 In the absence of any indication by the designer only Level ) access will be jncorporated into a new ductwork system
2 Tbe panel izes associated with Lev lis I and 3 acee s ar e middottablished by reference to Section 20 of DW144 and Section 2 ofTRll7 respectively
57
DW154 Speclfifatio for Plastics Ductwork
pA XE
B-bliography Included in this Bibliography are technical pUblications which may be of interest (0 ductwork designers fabricators and erectors and to tho e in the heating ventilatlng air conditioning industries generally nquiric should be made of the relevant organisation at the address quoted Since its publication other addresse contained within 0V154 mav have changed and some pubJicalions may have been superseded
HEATING AND VENTILATING CONTRACTORS ASSOCIATION
4 Palace Court London W2 4JG Telephone 020-7229 2488 Fax 020-7727 9268
Orders fo FlY A Publications Old Matlsion House Eamont Bridge Penrith Cumbria CA 10 2BX (Telephone 01768 864771 Fax 01768 86718) Email hvcapoblicationshvwelfarecouk DWn 44 pe ilicatiun for sheet mctal duclwork (Iow- mediulllshy
and high-pressure) 1998) DWIl4 A practical guide to dUGI ork I akage te ting
(revised 2000) DWII54 Specification for plastic~ duct rk DW171 Guide to good Practice for kitchen venlibtion system DW191 Guide to good pracuce glass fibre ductwoJk DwrrMI Acceptance cheme for new products - Redangolar cro
joint classification Guide to good pra tice - Internal cleanliness of new ductwork installations Guide to good practice for the design for the Installation of lire and smoke uampers
J 1Other puhlications
HampV safely guide 5th edition JS2 Tool box talks JS5 Weldlng Safety booklet JSI9 afety facts bo klet Fact sheets 1-24 2nd edition JS2J COSHH manual volume 1 Advice on compliance with the
regulations 1521A CO I-rH manual volume 2 Asses mcnt h ets JS23 Ri k management manual TR3 BrazinltT and bronze welding of copper pipework cUld sheet
(I 976) TR5 Welding of carbon steel pipework (1980)
TR6 Guide to Good Practice for Site Pre sure Testing of Pipework (19 0) Guide to good practice cleanliness of ventilation Ylem
CHARTERED IN TITUTlO OF BUILDING SERVICES E G EERS Delta House 222 Balham High Road London SW12 9BS rTelephone 020-8675 5211 Fax 020-8675 5449) CIBSE Guide Volume A Design Data Volume B In tallatiol1 and quipment Data Volume C Reference Data
CommlssioniJIg Codes These Codes eover the preliminary checkS eUing to work and regulation of vanous catcgories 0 plan The Codes give a guide to design implications Series A Air Distnbution Systems Series B Boiler Plant
ri s C Automatic Conlrol ystems Cr1es R Refrigerating Sy terns
Sene iN Water Distribution Systems
Technkal Memonllda TM 4 Design Notes for the Middle East TM bull Design otes for Ductwork TM 13 Minimi iog lhc Risk of egiounaires Disease
Research Reports RROI95 Ventilation system hygiene - A review of published
infomlatioo on lhe occurrence and ffects of Olltamination Rl~02J95 Air-to-air heal rec v ry RR0395 rnfluen e of HV C on smoke detectors
ATlONAL ENI [ERING SPECIFICATION LfMITED Southgatc hamber 3739 Southgate Street Winchester S023 9EH (Telephone 01962 842058 Fax 01962 R(8982) BUfLDING S RVICES RESEARCH AND [ ORMATION ASSOCIATIO Old Bracknell Lane West Bracknell Berkshire RG 12 4AH (Telephone Brackl1eU (01344) 426511 Fax 01344 487 -7 )
Application Guides AGln4 De tglJing Vana~le Volume middotylans for KOOnl
iir Movement AG1I91 Commissioning of V Sylcms in Buildings 11 6194 Fire Dampers
B) 94 cntiJalion or KitcneTls
AG389 The Commls ionin of Air Systems In Buildmgs AH2192 Commissioning of Bern - A ~ode of Practice TN2417 I Fire Dampec il) Ventilating Ducl
BEATING VENTILATING A AIR CONDITION G MA UFACTURERS ASSOCIATIO (HEVAC) HEVAC Henley Road Medmenham Marlow Buck SU 2ER (Telephone 01491 578674 ox 01491 575024 Emoimiddot infofetacouk)
Publicatjons Air Diffusion Guide Guide to Air Handling Unit Leakage Testing Guide to Good Practice Air Handling Unit Real Room Acoustic ~ st Procedure Specification for the ertiiicatioll ofAir Filters Method of Test for Water Rejection PerfOnTlatce of Louvrcs Subjected 1(1
Simulated Rainfall Test Procedure for Acoustic Loo cs Specification 10 Floor GrilJes - Types Performan e and Method ofTest Specification for the Determination of the Collection Efficiency of SilJ1d
Trap Louvre Domestic Mechwlical Vclltllalion Systems with Heal Recovery Fan Application Guid
~an and Ouctwork Installation Guide Guide to Fan Noise and Vibration
pecification of Requirements for JallJral Smoke and Heal Exhausl Ventilators
pecification for Powered Smoke and Heat Exhaust Ventilators
Specification of Requirements for Smoke Curtains Design Gujue of Smoke Ventilation for Single Storey Lodustrilll Building~
Including those with Mezzanine Floor and IIi Racked Storage Warehou es - Issue 3
Guidance for the Design of Smoke entilation YSlem for Covered and Undergrollnd Car Parks - lssue 1
Application of SOloke Control Equipment and Syst m Guid to Good Practice - Isue J
58
DW154 Sp(C~tiifitiol for Plastics Ductwork
BRITISH STANDARDS INSTIT TION Sales Department 101 P ntooviLle Road London NI 9ND (felephone 020-78 1 78801)
CP 413 1973 Ducts for building ervices
SS 476 Fire tes on building matenals and lruc(ure
Part 4 19 4 Non-combustibility lest or materials
Part 6 I Fire propagation lest for materials
Part 7 1993 Surface spread of tlarnJ tesls for materia
Part 20 1987 Fir resistance of elements of construction
Part 21 1987 Fire r sistlUlce of loadbeanng elements of construction
Part 22 1987 Fhe istallceofllon-loadbearing elemcllts ofconsttuclion Part 23 1987 Contribution of componcnts to the fire resistance 0 a
structure
Part 24t987 Fire resi lance of wl1lilation ductl
SS 5588 nan 919 0 Fire Precautions III thc desIgn and OOSlnJ lion of buildings
S 729 1971 Hot dip galvanized oatiugs (or irOIl aod stcel articles
BS 1449 Steel plate sheet and Irip
Pan 11991 Carbon steel plate heel and strip Part 2 1983 Stainless steel plate sheer and strip
and
B middotENJOI49-2 996 BSEN 10149- 1991)
BSEN 10131 1992
BSEN22063 Sprayed metal coarings 1994 Protection of iron and steel by aluminium and zinc against
atmospheric cOlosion Irotectiotl of iron and ste I against corro ion and oxishydation at elevared temperatures
BS 353 1981 Glossary of lerms relnting to thermal insulation
BS ISO 1479 Self-tapplngscrewsandmetallicdri c crew
B -lSO 7049
1994
B 4800 1989 Painl colour for building purposes B 4848 l0 rolled structural steel sections
Part4 1972 Equal and unequal angles BS 5422 1990 Specification for the use of therm illuating matcriulS
SS 5720 1979 ode of practice for mechanical veutilating and air C 11shy
dirionin bull in building
l3S PR 12814-1 Bend resting for plasric welds
SS PR 12814-2 Tensile testing for plastic welds
SS PR 13067 Appro altesting for plastic welds
BS PR EN I 100-] Vi ual in pection ofplaslic welds
SHEET METAL AND AIR CONDITIONING CONTR-CTORS NATIONAL ASSOCIATION INC (SMACNA) Headquarters 420 I Lafayeue Center Drive Chanlilly Virginia 2051-1209
Mailing Address pa Box 221230 Cbantilly Virginilt120 153-1230
Telephone (703) 803-2980 Fax (703) 803-3732
Accepted IJJdustry Pl3Gtice for Industrial Duct Constnlelion 197 ) i-rchitecmral Sheet kwl Manual ([993)
Comractors Guide lor Modification 10 ooslruerion Colllraets 1993 Ducted Eleclric Heat Guide for ir Handling Ssrerns (1994)
En~rgy ollservatioD Guidelines (1984) Energy Recovery Equipment yslClllS (199l
Fibrou GIns Duct onS1ntClion Standards (1992)
Fire Smoke amp Radiation Damper In tall Guide for HVA Syst ms (1992) Guide t leel Stack 1(95)
HVA Air Duct Leakage Test Manual (19 ) HVA COlllmissioning lvlanual (1994)
H A Duct Construction Standards-Metal amp Flexible (1995) Addendum 01 (Nov 1997)
HVA Duct Systems Inspection Guide (1989)
HVA ySlems-Application (1986) nVAC ByternS-DLlct D ign (1990)
HVi Systems-Testing Adjusting amp Balancing (1993)
indoor Air Quality Manual (1993) tcheu quipment Fabrication Guidelmes (1990)
Managers Guide for elding (1993)
Rectangular Industrial Duct Cons1TUction Standards (19 0) Round Industrial Duct oustmction Standards (1977)
Sei mic Restraint Manual (1991) (wl Appendix E 1993) SMACNA Ma le Index ()fTechnical Publications (1995) Tbennoplnstic Duct CPY ) Construction Manual 1994)
DEPARTME OF THE ENVIRO MENT (Publications Centre) H Stationery Oflice 5 Nine Elms Lane London SWS 5DR
MampEJ 011972 Electrical in tallat1011 in buildings ( ew Editiou)
IampE 0319 Healing hot and cold wat r steam and gas losla1lations for buildings
M amp - No4 1970 Central heating and hot and cold ~ ateT in tallations for
dwelling
M amp ENo100 1971 Mechanical ventilation for building~
ASSOCIATION FOR SPECIALIST FIRE PROTECTlO As ociation House 235 Ash Road AJdershot Hampshire GUl2 4DD
Telephone OJ25221322 Fax 0 J252 333901
lublicalioos Fire Ratcd and moke Outlet Ducrwork An Industry Guide t Design and InSlalla lioll
HEALTH AND SAFETY EXEC TIVE Rose Court 2 Southwark Bridge London SEl 9HS Telephone 020-7717 6000
TWJ THE WELD G TlTUTE Abington Hall Abington Cambridge CB16AL Telepbone 0 J223 89162
Publication DatJ Oil w~ldll1g of lhermopla lics
59
DW154 wciiwlioll for Plastics Ductwork
A -=--DIX
Factors
Specific gravity shy pp = 091 approx UPVC = 14 approx
Some miscellaneous conversion factors
To convert
Length Inches to millimetres Feet to metres
Multiply by
2540 03048
To convert
Millimetres to inches Metres to feet
vIultiply by
003937 3281
Area Square inches to square millimetres 6452 Square millimetres to square inches 000155 Square feet to square metres 00929 Square metres to square feet 10764
Volume Cubic feet to cubic metres Cubic feet to litres Gallons (UK) to litres
002832 2831 4546
Cubic metres to cubic feet Litres to cubic feet Litres to gallons (UK)
35315 00353
022
Mass Ounces to grams Pounds to kiJograms Tons to tonnes
2835 04536
1016
Grams to ounces Kilograms to pounds Tonnes to tons
003527 2205
09842
Volume flow Cubic feet per minute to cubic Cubic metres per second to cubic
metres per second 0000472 feet per minute 2119 Cubic feet per mIDute to litres Litres per second to cubic feet
per second 04719 per minute 2119
Motion Feet per minute to metres per second 000508 Metres per second to feet per minute 197
Pressure Inches water gauge to millibars 2491 Inches wateJ- gauge to pascals (Pa) 2491 I Pa = I ewton per square metre = 10-2 millibars
60
Heating and Ventilating Contractors Association Esca House 34 Palace Court London W2 4JG
Tel 020 7313 4900
e-mail contact Itvcaorguk web site wwwhvcaorguk
Fax 020 7727 9268
---
v
DW154 Spcc(fim(ml for Plastics Ductwork
Fig 34 Linear Thermal Expansion
u c 0 N ro 0)
b 0)
S
sect0
5 oS cl) 0)
~
on ~ ltl
c U
-30 -20 -10 0 10 20 30 40 50 60 70 80 90 TEMPRATURE C
~ V
-
~~c_ ~
~V
V ~
-7 ~
-- ~V ----
v
-6
+14
+12
+10
+8
+6
+4
+2
0
-2
--4
ig 35 Typical Design Stress tor UPVC and P
7
6
r shy 5E
-c E----0 4t) VJ 0)
ci5 0Jl 3
~
0)
Cl
2
1
o
UPVC
1
000
1
1
pp
- r-- shy r----- shy - t--shy I
__0
-30 -20 -10 0 10 20 30 40 50 60 70 80 90 TEMPERATURE C C
Note Figso 14 amp 35 shaded area refers to GRP reinforced duct
32
DW154 Speciicfltirm for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - REC ~NGULAR
Splilt~r Posilion W-mm pliucr
A B c 40]--QOO 1 W - -
601-1000 1 W4 Wf2 -
1001-1800 3 WI W3 W2
FIG DRAWING DETAfiS
tU]36 ATI Straight Duct with socket and spigol joint
rn [037 Straight Duct with flanged joints
[I []38 Straight Duct with flanged joints
rkJ Short Radius Bend
39 Applies to any augl and for duct up to 400 n11n wide
Minimum (I1m31 radills = 100 mm
Medium Radius Bend (a illustrated)
[kJ Applies to any angle
40 Long Radiu Bend Similar but radius = W
Throlll radius = W2 Applies to any angle
- Short Radius Bend with plitlers
I -shy -shy u co - t lt Li--_ 41 t 0 ~ I I I
~ I
L 1W
Minimum waal radius = 100 mm Splitters not required in bend angle less than 45deg
42 QJ1 Square Bend with turning vanes ij
3
DW154 SP(L~ficatioll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - RECTANGULAR
FIG DRAWl G DETADS
43
~
I v
L L Radius Tee with internal deflectors
44
~ Radiussed Twin Bend
45
Imiddot
er Swept Branch
46 U-
Sqoare Tee with Turning Vanes
47
~ f
Breeches Piece
48 0 y l Piece
34
DW154 Specificatioll for Plastics Ductwork
STANDARD COMPONENT RAWINGS - ECTANGULAR
55
54
51
50
53
52
49
FIG
~MX
RAWlNG
DmiddotMAX
EfjMAX
Minimum throat rndius = 100 mm
Rectangular shy Round Transformatioll
Eccentric Taper 225deg max in either plane Spliller are required for angles greater than 225deg and hould bi eet the angle between any side and duct centreline
DETATLS
Angled Offset
OUset Taper Splitters are required for angle greater than 22 0
and shoold bi eet the angl between any side and dUCI centrelinc
Mitred Offset
Concentrk Taper 2250 max in ither plane SpUtters are required for angle greater than 225deg and should bisect the angle between any side and duel c ntreline
Radiussed Offset
35
DW154 Splcilcuthm for Plastics Ductwork
STANDARD COMPONENT DRAWINGS ~ RECTANGU AR
Branch ducl DimCllsions widlh (W) (A)
urnl mm up lO 200 75
300 100 400 125 600 150
Ocr 600 200
FIG DRAWlNG DETAILS
56 poundplusmni~~ Rectan~lar - Flat Oval Transformation
57 [ Square Branch
58 er Angled Branch
Branch dUCI Dimensions wfdth (W) (A)
[- mm mm59 3shy Shoe Branch Up (0 200 75
--shy AIshy + 300 100
400 125
450 MAX 600 150
Over 600 200
Branch duct DimensIOn
rP X width (W) A)
60 - 1--shy _
~ mm mm
Bell Mouth Branch pto 200 75 300 100 t 400 125
600 150 Over 600 200
0=0 61 -
~ Bell Mouth
- shy T 4-5deg M x
--I 1-shy
TJ
62 X I ] I
Tele-scopic Joint I Illustrated with flangeL
X63
SBD Single Bladed Damper
36
---
DW154 Spedicatioll for Plastics Ductwork
STANDARD OMPONENT DRAWINGS - RECTANGULAR
DRAWING DETAILSFIG
64 on-Return DamperNRD shyshy
shyXbull
Multi-Leaf Damper Can be piggoted or flanged oppo cd or parallel blade
Alternative controls areshy
q p [gtshy
J HD65 Hand
~MD otori ed
PO Pneumalic
L-lt
l 13G 66 Blast Gate DamperX X
FireSmoke DampersSleeves
211r Ratinggtshy----
L_-
---
----
r----
Ir-- shy
IL- _-l
2hr
With i tallation frame
67 41 r Rating
4hr
Smoke damper SD
Intumc cent Sleeve L-d
37
DW154 Specijicutiolt for Plastics Ductwork
FIG
68
69
70
71
STANDARD COMPONET DRAWINGS shy REC ANGULAR
DRAVING DETAILS
gtshy Access Openings
AP 6 Access Panel - Rerno able
w [ ~ Access Door - Hinged
I ~le Inspection Cover
le -I reg -lt
~X X Flexible Connection
~ Drop Cheeked Radiussed Twin Bend
U Drop Cheek Bend
I
72 Air Flow SymbolX
38
DW154 Specifim[ioll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - ECTANGULAR
FIG DRAWING DETAILS
73
74
75
76
77
Q
Q
rp---t
~
V- I Ir---I
JL --11
THE ABOVE DETAILS TYPICAL PLENUM
Air Terminal Plenums
Plenum with side connection
Plenum with top connection
Cover plate with connection
Special plenum with connection
elescopic conn ction in direction of air flow
39
DW154 SpecijicotiOll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG
78
79
80
81
DRAWING
-23~---pound3-(MALE) (FEMAJE)
-t=j--_j(--d-shy
--L
~ THROAT RADI S= D AS T NDARD
e ~
THROAT Rjf)lU = D A MU)
DETAILS
Straight Duct With male and female connectors
Straight Duct With flange joint and slip joint
Bend MouldedIFormed Applies to any angle ego 30deg45deg60deg90deg Medium radius bend as illustrated Long radius similar but throat radius 0
Segmented Bend 90deg four section minjmum as illustrated
Other Angles 60deg = 3 sections 45deg = 3 sections 30deg = 2 sections
I
i
40 shy
DW154 Speciicafinll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG DRAWING DETAlLS
82 Segmented Twin Bend Radius = D2 max
May also be fabricated from tube
83 Equal Tee MouldedIFormed
84 -~ 1in Bend MouldedIFormed
85 Taper Concentric 1 0 as iUu trated Eccentric 30deg iJJcLuded angle
86 Short Taper
41
DW154 SpcUicatol1 for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG DRAWING DETAILS
87 30 max Offset
Angle Branch
Bran h dUCI Dimcnsions dia (D) lA)
Shoe Branch mm mm 88 Cl
Off rectanguJur Up 10 200 75 lOO 10 400 125
- 00 150 Over 600 200
Bl1IllCh duct DimenlOns din (D) (A
~-$a-Conical Branch mm mm
89 Also acceptable with Up 10 200 r
full conical surface 300 10
400 125
END VrE -shy 600 150 Over 600 200
90
m 75
100 12 150 200
mm Up to 200
_ 300 400
600 Over 600
iUtred Branch
Shoe Branch
J-L----U ~ Bell oulh Branch
ENDV1EW
93
92
91
42
DW154 Specificatiol for Plastics Ductwork
STANDARD OMPONENT DRAWINGS - CIRCULAR
FIG
94
DRAW G
I
~ 30deg 090deg
Breeches Piece
DETAILS
95 amp-----~ Blank End
~-----p Multi-Leaf Damper Can be piggolcd or fianged opposed or parallel blade
Alternative controls areshyri=-+- L-T~
I
---
LT~
I r- -
-+1
J HO Hand96
bMD Molori cd
PD Pneumatic
tl-shy bull
Single Bladed Damper 97 ~ saD
on-Return Damper Vertical application only 98 m~D
43
DW154 Sf1tcificatioll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG
99
100
101
102
DRAWING
$ I-
2hr
1 4hr
SD
~v I I
CO TINENTAL COWL
DETAILS
Iris Damper
Fi reS moke Dam persSleeves
2hr Ratillg
With installation frame
4br Rating
Smoke damper
Intumescent Sleeve
Access Openings
Access panel - removable
Access door shy hinged
fnspection cover
Discharge Continental Cowl
44
DW154 Sp(Cii(ltJll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
DRAWINGltIC DETAns
-
I
I
~
I I I High Velocity Discharge Terminal 103 I
I
I I
J I I 1 ~--
Offset Stack Discbarge Terminal 104 1
~ I e --(-
I
N
I
I
I~
I I Vertical Oischarge with Weather Cowl 105 I
--1--1 I
I
GAPI I
RTl AL DISC) lARGE WITH W ATIIER COWL
45
DW154 SpecUicatoll for Plastics Ductwork
STANDARD COMPONE T DRAWINGS - PLA TEQUIPMENTIMISCELLANEOU
FIG DRAWING DETAILS
106 ~~~ Rectangular Attenuator
107 ~- Circular Attenuator
108
~ Beod Attenuator
109 J ~(f) Heating Coil
110 J ftte Cooling Coil
III Jc[ Electric Heating Coil
112 X F
Humidifier
113 [H XX Axial Fan
114 ~fB1famp Noo-standard Ductwork Cross hntchillg (of any separate type) indicates by reference to a key any non DVil54 ductwork system
115 2llIIIIJIIIIIll Flexible Ductwork
46
DW154 SJeCUicll(iol1 for Plastics Ductwork
TABLE 12 - STANDARD ABBREVIAT ONS
ABBREVIATION FLL
AD Acces Door
AFF Axial Flow Fan
AHU Air Handling nit
All Aluminium
AP Acess Panel
AT Attenuator
AV Air enninal Unit
BE 81ank nd
BQ Blast ate Damper
CC Cooling Coil
CF Centrifugal Fan
CTA Cross alk Attenuator
CVU Constant Volume Unit
DP Drain Point
EEC Electric Heating Coil
El Expansion Joint
FAl Fresh Air Inlet
FA From Above
FB From Belo
fBPP Fabric Backed Polypropyl-ne Sheet
Flexle Flexible Connection
lexfD Flexible Du t
C False Ceiling CO an oil Unit
fD Fire Damper
FFL Finished Floor Level
FJ Flanged Joint
FOAM Rigid Polyurethane Self xtinguishing Foam
FOB Flat on Bottom
FOT Flat on Top
GAM Galvanised after ManufacttrJc
GRP Glass Reinforced Plastic
GSS Galvanised Sheet Steel
HC Heating oil
HD and controlled Damper
HH Hand Hole
HL High Level
HVD High Velocity Discharge
IC Inspection Cover
ID lri Damper
IFS Intumescent Fircleevc
47
DW154 Specification for Plastics Ductwork
TABLE 12 - STANDAR ABBREVIATION CONTINUED
ABBREVIATION
IU
L
tv1D
MS
NRD NTS
OBO
OE
PHD
PD
PP
PP
PRD
PVC
RFC
RSC
R
SBO
SO
S1 TST
SSL
TA
TB
TO TJ
TP
TV
TV
OS
UPVC
S
V
VAV
50 RSA
FULL
Induction Unit
Low Level
Motor controlled Damper
Mjld Steel
on Return Damper
at to cale
Opposed Blade Damper
Open End
Parallel Blade Damper
Pneumatic controlled Damper
Polypropylene
Self xtinguishing Polypropylene
Pressure Relief Damper
Polyvinyl Chloride
Rolled Form Chamlel
Rolled Steel Channel
R fUnit
Singl Blade Damper
Smoke Damper
Slip Joint
Stainl t el
tructural Slab Level
To Ab vc
To Blow
Top Down (In Direction of Flow)
Telescopic Joint
Test Point
TU111iog Vane
Top Up (In Direction of Flo )
Voles Otherwise Stated
Unpl3sticisecl Polyvinyl Chloride
Underside
Ultra Violet Light
Variable Air Volume
Rolled Steel Angle (Vith Size)
48
DW154 SJeriiflllioll for Plastics Ductwork
A2 DUCT PRESSUREAPPE DXA Ductwork con truct d to DWIl54 will bebullbullbullbullbullbullbullbullbullbullbullbullbullbull
Air Leakage From Ductwork To be read in conjunction with DW143 A practical guide to Ductwork Leakage Testing
CAUTION As highlighted ill both this docul1lenr and DW14 I lot ellough emphasis can be placed 01 the fact that except for high pressure class C the much more stringent ductwork constructional standard brolght about b the general acceptance of DW154 have irtlally negated the requirement for leakage-testing It is essential lO realise lhat except where it is mandatory this doclllllelll is nOl an endors ~lIlent of the rourine testing of ducts bllt purely a guide to outline the procedures for cononnity with the air leakage limits ill Table l Where the specified methods of assembly and
A3sealing of dlcls are u ed a vi ual inspection wil ordinarily sl~fll e for ver(iatioll of a well engineered and a ceptahfy airtight COl1strucrioll WHERE NOT MANDATORY DUCT LEAKAGE TESTING IS GENERALLY AN UNJUSTIFIED AND SUBSTANTIAL EXPENSE
A1 INTRODUCTION L akage from ducted air distribution systems is an Lmportant consideration in the design and operation of ventilatjon and air conditioning middotystems A ductviork t)ystem tbat ba limited air leakag within defiucd limits wiH cnsUft
that tile design characteristics of the sytem can be maintained It wilJ also ensure that energy and operatLonal cosb are maintained at optimum levels DucLwork constlucted and Ulstalled in accordance with DW154 should minimise a level of air leakage that it) appropriate to tll operating static air pre sur in tile system
A4However it is recouuised that tbe environment in wtJich middotystems are installed is not always conducive to achieving a predictable level of quality in term of system ajr leakage and it is therefore accepted that designer may sometimes require tlle ystem to be tested in part or in total It should be ecogni ed that the testing of duct systems add a ignificant cost to the installation and incur some extra tjm within the programme (Se 47 and 64 re mandatory te-sting)
manufactured to a structural standard that is compatible with the system operating pressure There are three classes of duct con truction to eorre pond with the three pre ure clas meations Class A Lo pressure ducts suita le for a maximum positive operating pressure of 500 Pascal and a maximum negative pressure of -500 Pascals Class B IVledium pressure ductmiddot suitable for a rnaxilnuJJl positive operafjn o pressure of 1000 Pascals and a maxllnum negative pre sure of -750 Pa cal Class C High pre sure ducts suitable for a maximum po ilive operating pressur of 2000 Pa cals and a maximum negativ pres ur of -750 Paltcals
LEAKAGE FROM DUCTWORK Leakao-e front pia tic air ducts occur at the joint~ and is therefore proportional to the total surface area orthe du twork in th system Tb level of leakage i imilarly related to tIle air pres ure in th du t system and whilst there LS n precis formula for calculating the level of air los it i generally accepted that leakage will increase in proportjon to pressure to rbe pOvver of 065 The effect of air leakage from high pressure velocit ductwork is critical tn terms of system perfomlan dege energy consumption and the risk of high frequency noise as ociated with leakage These problems are le critical with medium pressure 10 ity systems but should be con idered Low pres mevelocity ducts present the lowe~t
ri k in tenn of tbe effect of leakage on the operation of the s stern
SYSTEM LEAKAGE LOSS As there i no di ct relatLonship between th volume of air conv yed and the surface area f the ductwork sy tern required to match the building configuratmn it is difficult to express air leakage a a percentage of total air volume Similarly the operating pressure will vary throughollt lh 3 system and a leakage is related to pre me the calculations ar comple However it is generally ac epted tbat in typical good quaJjty systems the leakage from
49
DW154 Specificatioll for Plastics Ductwork
each class of duct llnd r operating condition will be io the region of CIa S A low pressure 6 Clas B medium pres un 3 Clas C high pressure 2
A5 SPECIFYING AIR LEAKAGE TESTING Re peeting both the co -t and programme implications a sociated with te ling du 1 for leakage the designer may for example indicate that a particular system is te ted as follow
a) High pressure ducts - all tested b) Medium pr ssure duets - 10 of the
ductwork shall be s eet d at random and tested
c) Low pre sure - unte ed In any case where a random te t i elected for medium pre sure ductmiddot the followin c1au~e is suggested for inclusion by the de ign r
The designer hall elect at random a maxirnwlI of 10 of the dUCl system to bt tested for air leakage The duct hall be tested af the pressure recommended in Table J3 for the assifi atiol for the ectiol1 of the ductwork that is to be tested The tests shall be carried Ollt as the work proceeds and prior to the application of thermal insulation In the event of test failure of the randomlY selected section the designer shall have The right to select two La1her e tiolls at random for resting Where succes ive failures are identified there shall be a Tight to require rhl COl11raCWr 10 apply remedial attention to the complete ductwork system Th contractor shall provide documented eviden e of the calculalions used to arrive (1
the allowable 10 I for the section to be tested and the client or his agent shall willess and sign the results of the test
able 13 Air leakage rates
Maximum leakage of duct work Static
prcssUft Low-pressure edium-prc-sure I Iigh-prebull me diJfercntial Class A Class B Class C
1 2 J 4 Pa Litres per second per quare metre of surface area 100 054 018 ZOO 084 028 300 110 037 400 132 044 500 153 051 600 058 019 700 064 021 800 069 023 900 075 025
1000 080 027 1100 1200 1300 1400 1500
029 030 032 033 035
1600 1700 1800 1900 2000
036 038 039 040 042
Note Recommend d mean test presures are highlighted iD bold type with the actual selection being left to tll test operator
50
DW154 Sfeeiieaioll for Plastics Ductwork
A9
A10
and air leakage classification for the y em under test
DESIGNERS CALCULATIONS The designer can middotaJculate with reasonable accuracy the predicted total loss from a ystem by
a) Calculating the operatin presure in each ection of the sy tern
b) Calculating the surface area of the ductwork in each correspondin pre lire s ction
c) Calulating the allowabl~ los at the operating pressure for each ection of the system (see table 13 for allowable leakage figures)
VARIABLE PRESSUR S IN SYSTEMS De igner can achieve significant co t saving by matchina operating pressures throughout the system to constmctional standard and appropriate air leakage testing eO the practice of specifying construction tandards for whole duct sy tems based on fan discharge pre sure may incur unnece sary costs on a project For example ome large sy terns ould well be classiC ed for I akage limits as follows
Plant room risers CJas C Main floor distriblltJou CIa B Low pre sure outlets Cla A
A6 SPECIAL CASES There may be ~itLlations on a project where circumstance dictate thal pecial consideration be given to containing air loss s eg a long mn of duclwork may incur a di -proportjonate level of air 10 s In ca es such as thi example the designer can specify an improved tandard of airtighmess ie 80 of alJo~able 10 s for la B Ju ts The designer sbould not specif a CIa C t sI at CIa s C pressure for a CIa s B ducl
A7 SUGG S ED RANGE OF TES ING
A8 TESTING OF PLANT ITEMS Items of inline pJant (eg Fig 106 to 115) will not normaUy be included in an air I akage test The dllctwork contractor may indud such itelllS in tbe te t jf rh quipm ot has a certificate of COnfOlnlity for Ihe pres ure clas
bull High pressure duct bull Medium pre sure ducts bull Low pre sur ducts bull Exposed extract syst ID bull Ceiling void extract
systems bull Secondary ducts from
VAV or fan coil units bull Flexjble duct bull Final connections and
branches to grille and diffusers
100 test See A5 Untested UDt sted
Untested
Untested Untested
Untested
SI
i
DW154 SJecijicafion for Plastics Ductwork
ig 116 Permitted leakage at various pressures
Leakage in litres per second per square metre duct surface area
Vgt
o ltgt 0 ltgt N
ltgt Cgt
0 0 cc
0 0
~
g =
g ~
c 0
J
ltgt 0 I
~ ] tn
ltgt ltgt
In ol
~ 0 ~ 8 ~
~
c ltgt ltgt
~ CJ
~ ~ ~ ~ 8
0shyij
~ ~ ~ t
ltgt ltgt 00
l
~
~ Q
c C
~ rshy
e ltgt
I 1
I Cgt ltgtv
c Co ~
~~ ~ 10
I
0 Cgt
fJshyq 410 ) 1 ltgt
ltgt N
~ shy ltgt ltgt
~ I 1
c
52
DW154 Specificatio for Plastics Ductwork
Example of a completed test sheet Test No
General
Name of job N~ jC43Pt(r2lef Building Repound ~(~~0
Part 1 - Physical details
a Section of duct work to be tested ~(diffPIfff~el1f3rd Floor
b Drawing Number g91~~ c ssure aSSJ L atlOn V~Jl~IRfYgtg~~lPre Cl T Class C
d Test static pressure -(9 raErq~ ~~~~-~~J~~~ ~~ ~~~~ll
Leakaoe factor 9~-tre3$ecMz I OM REFTOTABLE 13)e b bullbullbullbullbullbullbull
f Surface area of duct under test Q~tJJItetre$ CPROMCALCU TIO BELOW)bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull ampampamp bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull
g ]Vlaxi mum permitted leakage -~ (~i~~0 ~~r~~ ~~~l-~-11~ ~~~Q
Part 2 - Test particulars
a Duct static pressure reading 9QFt~q~ ~ middot~~~1 ~~
b Manufacturer and type of liow measuring d vice (-~~~cJ~Y-9Q7EYg c Range of measurement of now measuring device QtP)OQ~(e~~~0I~~~~1~I~ ~~~~~~W~
d Reading of flm measurin o device pmiddot IFROM RIO)ftscag ~
I (DERlVED [ROM CHART SUPPUED WITH RIG US 0 ud)1e Interpreted air flow leakage rate ~(~~~f~~~ (~l~~~~~~~~~~~~~~~~~I
f Duration ~~~~~norn~allY l~ lnil1Ut~~d~~~ it1~ W~ Date of test ~(lITled ut by Wltll s ed by ~ ~
(~lJ MIJLrr) (Si~rrfltJUYJ
Printed Name 1~g0f~ Printed Name ~~Y~9~ and Company 7jl~~~~~( UJd CompanY AB COII$Itallt8
Width and depth or diameter
Periphery ength Area
millimetreS millimetres metre qL1are metre
800 x 750 3100 1755 5440
600 x 650 2500 557 1193
300 x 300 1200 120 144
305 din 958 700 670
250 dia 785 450 353
TOTAL 8000
53
DW154 Specijilarion for Plastics Ductwork
pA XB
Guida ce No es For he ransport Handling and
Storage of uctwork
avoid damage to adjacent duct panels In somc ca es particularly on con acts calling f r repetitive sizes the use of timber jigs and spacers may be justified Where reduced bulk and greater protection are major factor such as consignments for export transporting ductwork in L shape sections may justify the increa ed ite as embly co ts
It is recommended that before a contract is finalised that consideration is given to the subject of site acces material handling and storage as tbcy havgt a strong influence on the cost efficiency of the overall activity of ductwOlk installation
B3 Handling To minilnise th risk of damage duct sections should be clearly identified and deliveries to site should be closely linked to the installation programme so as to avoid accumulation of
B1 Storage and Handling of Ra Material Material should be stored in suitably designed racking out of direct unJight Where possible the e racks should be metal to earth Edges of cut she t may be harp and protective gloves are advised Wearing teel toe-capped boots is recommended Most pIa tic sheet is manufactured with smootb mfaces andor is suppLied with protective coating Care must be taken to prevent accidental lippag of stacked materials Beiuoshy good electrical insulators the movement of stock unless earthed will allow the build up of stati All stock shapes are chemically stable at normal temperature Whil t some raw materials used in their manufacture may themselves pre ent a toxic hazard once incorporated into the lOck bape they no long r constitute such a hazard and no dermatitic bazard are known nor are any
unfiJied ductwork and minimise double handling It is important to recognise that ductwork panels joint and corners arc susceptible to damage and care must be taken wheu band ling such material through a site During handling individual item of duct work may be liable to light cross sectional deformation until thev become an integral pan of a completed ductwork system Whilst this may temporarily detract from its intended appearance thi deformation will not have any detrimental effect on the functionality of the finally a semblecl system Installation of duct work and asociated plant items ill illevitably involve manual handUng The responsibi Iiry of employers and employees to a ses the risk of personal injury during mallual handling operations is et out in the HS E publication L23 Guidance on Manual Handling Regulations 1992
environmental problems expected 84 Site storage
B2 fransport Large capacity vehicles with high-sided open or closed-top bodies are tlle mo t suitable for the transport of dllctwork Careful consideration should be given to the
Adequate floor space IDust be provided within tbe building for the site storage of ductvork Such storage shalt make due allowance for thc stOf(ne of ductwork in stacks such that access ~ egt
between them is of sufficient width to pennil the removal of item without interference to
unloading of transport on sit a not all siJes b n fit from the material handlino- and access facilities that exi [ in a manufacturing workshop such as crane- fork-lifts or loading bay Site handJiog facilities along with
adjoining sta ks Ductvork components should be positioned so a to avoid crushing Ductwork of small panel size may be stored horizontally however care should be exercised to ensure that tack sizes are limited 10 within
ehicular acce s restrictions may itilluence the type and ize of transport to be uWised
engtlls of ductwork should be positioned 0
the tmctural strength of the duct sections to prevent distortion of the lower sections within the stack
as to avoid crushing Lengths Witll projections such as branches and bends i1anges girths damper quadrauL should be loaded so as to
54
DW154 S1tciic(ltioll for Plastics Ductwork
85 Internal cleanliness of new ductwork The site storage of ductwork introduces the important cODsideration of maintaining the internal cleanliness of the ductwork R feren e should be made to HVCA documentshybull DWffM2 Guide to Good Practice - internal
Cleanliness of New Ductwork Installations If the above conditioDs can not be satisfied consideration should be given by tJle designer to amending the specification to include for Po t Installation Cleaning as covered by tJ1C HVCA documentshybull TRJ17 Guide to Good Practic - Cleanliness
of Ventilation Systems
APPE DIXC
Fi e Retardant inishes C1 Improvement in the fire retardancy of plastic
ducts can be achieved to varying degrees and is wholly dependent llPOll the surface coating laminating resin selected and construction specification adopted In some instances smoke emission is coILSidered equaUy with other speci fication requirernen ts of the materials resistance to ignition and bumjng It is therefore important for design rs to establ ish the clients and officers detailed requirements and not rely on a tbird party interpretation of fire resisting or fire retardant Where possible the specification should refer dir etly to compliance with a British or European Standard identifying the specific sections applicable There are various types of resin and mat rcLnforcements that can achieve a Class 1 surface spread of flame ratin o when tested according to BS476 Part 7 (1987) This test puts materials illto Class I - 4 in descending order of perfoDllance according to the rat and extent of flame spread over their surfac under standard beating conditions Materials should also be tested for flre propagarion to BS476 Part 6 (1989) Tbi tesr measures the amount and rate of heat evolved by the material when subjected to standard heating
conditions Test results are given as an index of Perfonnance (i) whicb is based on three sub indices (iJ (i1) (h) The higher the value of the Index of Performance (i) the greater is the material s contribution to fire growth The higher the value of the sub-index 0) rhe greater the ease of ignition aod flame spread The highest product performance classification as defined in Approved Document B of the Building Regulations is Class O This is acLlieved if a material surface of a composite ploduct i~ either a) composed throughout of materials of
limited combustibility or b) a Class I material which has a tlre
propagation index (i) of not more than 12 and sub-index (i l ) of nor more than 6
01 J Class 0 is not a cla$sif1cation identified in any British Standard test
There are resin system reported to be classified to Class O when tested to BS476 Pcl1S 6 and 7 however designers need to ensure that such sysrems can be applied to their proposed design In propriety resinmat system available the fabrication techniques and COITect application are critical to the integrity of the reinforcing and clas ificatiol1 For example in some systems the u e of a non-fire retardant gelcont on a fire retardant substrate would reduce the classification For further information see HVCA publication DW144 Appendix D
55
DW154 SplCijiClIliol1 for Plastics Ductwork
x Guidance otes For nspectmiddoton Servicing a d
Clean-ng Access Openings
D1 GE ERAL This appendix highlight in ummary fOI111
the acce considerations that hould be made by the design r iD terms of inspection servicing and cleaning Having considered the seop and the design of the dUCI work system relative to the guidelines outlined below the designer should clearly indicate which levels of acces should be incorporated into the manufacture of a new duct work system (See Table 14 and Note I b low it
D2 DESIGN CONSIDERATIONS
D21 In ptction and servicing requireshyments are set out in Section 15 of Lhis specification
D22 Cleaning requirements are set out in the HVCA pubUcation TRl7 Guide to Good Practice Clean Lines of Ventilation Systems and the guide tates The precise location ize and
type of access would be dependent on the type of ductwork cleaning inspection and te ting metbods to b adopted Care protection and standards of cleanliness prior LO cOlllmisionin o
are set out in th AV A publication DWITM2 Guide to Good Practice Internal Cleanliness of New Ductwork Installations and th guide state Wh re specific limits of cleanliness are required ductwork sball be cleaned after installation by a spcialist cleaning contractor It will b in the interests of tht desioner botb financially and practically to cunsider employing a specialist c1eauing contractor at tbe
outset of a contract to internally clean newly installed ductwork prior to bandover This approach would reali e the following benefit shyi) Tb actual numb r of cleaning
access panels could be detennined to suit the method of cleaning to be adopted (This may be 1 s than the maximum requiremen listed under Lev 13 of Table 14)
ii) Clear directions could b given to the ductwork contractor as to tJle size and location of cleaning access panels that are required to be fitted during the mauushyfaclunng pro s
iii) The specialist cleaning operation prior to commi ioning vould enable the cleaning contractor to verify the practical acee requirement for the future cleaning operation associated -vitb a regular maintenance programme
iv) A specialist cleaning operation prior to commissioning would allow the designer to omit from the speeilicatiolJ the DWrrM2 requirem nt for factory sealing protection wipe downs and capping-off
v) Specialist Ieall ill 0 to the measurable standard defin d in TR17 will allow an objective definition of cleanline to be achieved
Car ful consideration must be gIven by the designer to the practl aJ problems associated witb the manufacture and fitting of suitably si Led access panel on small cross section duct and on the circular faces of rouod and flat oval ducts in particular
D23 Special con ideration must be given by the de igner to the practical problems associated with gaining personnel access to heavily congested ceiling areas and multi-la red du twork systems This approach would avoid
56
DW154 Spfciication for Plastics Ductwork
the possibility of access panels being D3 ACCESS 0 IN-LINE EQUIPMENT incorporated into a ductwork system at the This appendix unly covers acc il1spection manufacturing stage that were later found in through the ductwork body adjacent to an item practice to be inaccessible for either ervicing of in-line equipment and not openings in the or cleaning activities equipment itself
able 14 Acce requirements for inspection servicing and cleaning
HVCA PUBLICATIO REFE NeE (uidtgt 10 Gund Prartict
Adjace t OW144 Cleanliness orVcnlillltio S~lcr~ fRjJ7
in-line LeyeJ 1 Level 2 Level 3 ite sequipment pcdionSen lcin~ Section d C1eaniJl( SUn(O)lnspc lion Palle ltk~m_n
2011 (minimum OiL Jubje-ct to duct ~zel (ft~ -Panels
Control Da pcrs One (inspection) 203 One 300 mm x 200 mm Both sid Fire Dampers One (sCTjdJl~) 20211 One 300 0101 x 200 mm One side HeatingCooling Coils One (inspedion) 20213 One 300 mm x 200 mm (lIpstream) Both sides Attenuators (rectangular) None required One 300 mm x 200 mm (downstream) Both sides Attenuators (circular) one retluired One 300 mm x 200 mm (downstream) One side Filter Sections One (inspection) 20212 one required Uoth sides Air Turn Vanes None requjred None required Both sides Changes of Direction None required one required One side In-Duct FansDevices One (inspection) 20213 None required Both sides l
1 In the absence of any indication by the designer only Level ) access will be jncorporated into a new ductwork system
2 Tbe panel izes associated with Lev lis I and 3 acee s ar e middottablished by reference to Section 20 of DW144 and Section 2 ofTRll7 respectively
57
DW154 Speclfifatio for Plastics Ductwork
pA XE
B-bliography Included in this Bibliography are technical pUblications which may be of interest (0 ductwork designers fabricators and erectors and to tho e in the heating ventilatlng air conditioning industries generally nquiric should be made of the relevant organisation at the address quoted Since its publication other addresse contained within 0V154 mav have changed and some pubJicalions may have been superseded
HEATING AND VENTILATING CONTRACTORS ASSOCIATION
4 Palace Court London W2 4JG Telephone 020-7229 2488 Fax 020-7727 9268
Orders fo FlY A Publications Old Matlsion House Eamont Bridge Penrith Cumbria CA 10 2BX (Telephone 01768 864771 Fax 01768 86718) Email hvcapoblicationshvwelfarecouk DWn 44 pe ilicatiun for sheet mctal duclwork (Iow- mediulllshy
and high-pressure) 1998) DWIl4 A practical guide to dUGI ork I akage te ting
(revised 2000) DWII54 Specification for plastic~ duct rk DW171 Guide to good Practice for kitchen venlibtion system DW191 Guide to good pracuce glass fibre ductwoJk DwrrMI Acceptance cheme for new products - Redangolar cro
joint classification Guide to good pra tice - Internal cleanliness of new ductwork installations Guide to good practice for the design for the Installation of lire and smoke uampers
J 1Other puhlications
HampV safely guide 5th edition JS2 Tool box talks JS5 Weldlng Safety booklet JSI9 afety facts bo klet Fact sheets 1-24 2nd edition JS2J COSHH manual volume 1 Advice on compliance with the
regulations 1521A CO I-rH manual volume 2 Asses mcnt h ets JS23 Ri k management manual TR3 BrazinltT and bronze welding of copper pipework cUld sheet
(I 976) TR5 Welding of carbon steel pipework (1980)
TR6 Guide to Good Practice for Site Pre sure Testing of Pipework (19 0) Guide to good practice cleanliness of ventilation Ylem
CHARTERED IN TITUTlO OF BUILDING SERVICES E G EERS Delta House 222 Balham High Road London SW12 9BS rTelephone 020-8675 5211 Fax 020-8675 5449) CIBSE Guide Volume A Design Data Volume B In tallatiol1 and quipment Data Volume C Reference Data
CommlssioniJIg Codes These Codes eover the preliminary checkS eUing to work and regulation of vanous catcgories 0 plan The Codes give a guide to design implications Series A Air Distnbution Systems Series B Boiler Plant
ri s C Automatic Conlrol ystems Cr1es R Refrigerating Sy terns
Sene iN Water Distribution Systems
Technkal Memonllda TM 4 Design Notes for the Middle East TM bull Design otes for Ductwork TM 13 Minimi iog lhc Risk of egiounaires Disease
Research Reports RROI95 Ventilation system hygiene - A review of published
infomlatioo on lhe occurrence and ffects of Olltamination Rl~02J95 Air-to-air heal rec v ry RR0395 rnfluen e of HV C on smoke detectors
ATlONAL ENI [ERING SPECIFICATION LfMITED Southgatc hamber 3739 Southgate Street Winchester S023 9EH (Telephone 01962 842058 Fax 01962 R(8982) BUfLDING S RVICES RESEARCH AND [ ORMATION ASSOCIATIO Old Bracknell Lane West Bracknell Berkshire RG 12 4AH (Telephone Brackl1eU (01344) 426511 Fax 01344 487 -7 )
Application Guides AGln4 De tglJing Vana~le Volume middotylans for KOOnl
iir Movement AG1I91 Commissioning of V Sylcms in Buildings 11 6194 Fire Dampers
B) 94 cntiJalion or KitcneTls
AG389 The Commls ionin of Air Systems In Buildmgs AH2192 Commissioning of Bern - A ~ode of Practice TN2417 I Fire Dampec il) Ventilating Ducl
BEATING VENTILATING A AIR CONDITION G MA UFACTURERS ASSOCIATIO (HEVAC) HEVAC Henley Road Medmenham Marlow Buck SU 2ER (Telephone 01491 578674 ox 01491 575024 Emoimiddot infofetacouk)
Publicatjons Air Diffusion Guide Guide to Air Handling Unit Leakage Testing Guide to Good Practice Air Handling Unit Real Room Acoustic ~ st Procedure Specification for the ertiiicatioll ofAir Filters Method of Test for Water Rejection PerfOnTlatce of Louvrcs Subjected 1(1
Simulated Rainfall Test Procedure for Acoustic Loo cs Specification 10 Floor GrilJes - Types Performan e and Method ofTest Specification for the Determination of the Collection Efficiency of SilJ1d
Trap Louvre Domestic Mechwlical Vclltllalion Systems with Heal Recovery Fan Application Guid
~an and Ouctwork Installation Guide Guide to Fan Noise and Vibration
pecification of Requirements for JallJral Smoke and Heal Exhausl Ventilators
pecification for Powered Smoke and Heat Exhaust Ventilators
Specification of Requirements for Smoke Curtains Design Gujue of Smoke Ventilation for Single Storey Lodustrilll Building~
Including those with Mezzanine Floor and IIi Racked Storage Warehou es - Issue 3
Guidance for the Design of Smoke entilation YSlem for Covered and Undergrollnd Car Parks - lssue 1
Application of SOloke Control Equipment and Syst m Guid to Good Practice - Isue J
58
DW154 Sp(C~tiifitiol for Plastics Ductwork
BRITISH STANDARDS INSTIT TION Sales Department 101 P ntooviLle Road London NI 9ND (felephone 020-78 1 78801)
CP 413 1973 Ducts for building ervices
SS 476 Fire tes on building matenals and lruc(ure
Part 4 19 4 Non-combustibility lest or materials
Part 6 I Fire propagation lest for materials
Part 7 1993 Surface spread of tlarnJ tesls for materia
Part 20 1987 Fir resistance of elements of construction
Part 21 1987 Fire r sistlUlce of loadbeanng elements of construction
Part 22 1987 Fhe istallceofllon-loadbearing elemcllts ofconsttuclion Part 23 1987 Contribution of componcnts to the fire resistance 0 a
structure
Part 24t987 Fire resi lance of wl1lilation ductl
SS 5588 nan 919 0 Fire Precautions III thc desIgn and OOSlnJ lion of buildings
S 729 1971 Hot dip galvanized oatiugs (or irOIl aod stcel articles
BS 1449 Steel plate sheet and Irip
Pan 11991 Carbon steel plate heel and strip Part 2 1983 Stainless steel plate sheer and strip
and
B middotENJOI49-2 996 BSEN 10149- 1991)
BSEN 10131 1992
BSEN22063 Sprayed metal coarings 1994 Protection of iron and steel by aluminium and zinc against
atmospheric cOlosion Irotectiotl of iron and ste I against corro ion and oxishydation at elevared temperatures
BS 353 1981 Glossary of lerms relnting to thermal insulation
BS ISO 1479 Self-tapplngscrewsandmetallicdri c crew
B -lSO 7049
1994
B 4800 1989 Painl colour for building purposes B 4848 l0 rolled structural steel sections
Part4 1972 Equal and unequal angles BS 5422 1990 Specification for the use of therm illuating matcriulS
SS 5720 1979 ode of practice for mechanical veutilating and air C 11shy
dirionin bull in building
l3S PR 12814-1 Bend resting for plasric welds
SS PR 12814-2 Tensile testing for plastic welds
SS PR 13067 Appro altesting for plastic welds
BS PR EN I 100-] Vi ual in pection ofplaslic welds
SHEET METAL AND AIR CONDITIONING CONTR-CTORS NATIONAL ASSOCIATION INC (SMACNA) Headquarters 420 I Lafayeue Center Drive Chanlilly Virginia 2051-1209
Mailing Address pa Box 221230 Cbantilly Virginilt120 153-1230
Telephone (703) 803-2980 Fax (703) 803-3732
Accepted IJJdustry Pl3Gtice for Industrial Duct Constnlelion 197 ) i-rchitecmral Sheet kwl Manual ([993)
Comractors Guide lor Modification 10 ooslruerion Colllraets 1993 Ducted Eleclric Heat Guide for ir Handling Ssrerns (1994)
En~rgy ollservatioD Guidelines (1984) Energy Recovery Equipment yslClllS (199l
Fibrou GIns Duct onS1ntClion Standards (1992)
Fire Smoke amp Radiation Damper In tall Guide for HVA Syst ms (1992) Guide t leel Stack 1(95)
HVA Air Duct Leakage Test Manual (19 ) HVA COlllmissioning lvlanual (1994)
H A Duct Construction Standards-Metal amp Flexible (1995) Addendum 01 (Nov 1997)
HVA Duct Systems Inspection Guide (1989)
HVA ySlems-Application (1986) nVAC ByternS-DLlct D ign (1990)
HVi Systems-Testing Adjusting amp Balancing (1993)
indoor Air Quality Manual (1993) tcheu quipment Fabrication Guidelmes (1990)
Managers Guide for elding (1993)
Rectangular Industrial Duct Cons1TUction Standards (19 0) Round Industrial Duct oustmction Standards (1977)
Sei mic Restraint Manual (1991) (wl Appendix E 1993) SMACNA Ma le Index ()fTechnical Publications (1995) Tbennoplnstic Duct CPY ) Construction Manual 1994)
DEPARTME OF THE ENVIRO MENT (Publications Centre) H Stationery Oflice 5 Nine Elms Lane London SWS 5DR
MampEJ 011972 Electrical in tallat1011 in buildings ( ew Editiou)
IampE 0319 Healing hot and cold wat r steam and gas losla1lations for buildings
M amp - No4 1970 Central heating and hot and cold ~ ateT in tallations for
dwelling
M amp ENo100 1971 Mechanical ventilation for building~
ASSOCIATION FOR SPECIALIST FIRE PROTECTlO As ociation House 235 Ash Road AJdershot Hampshire GUl2 4DD
Telephone OJ25221322 Fax 0 J252 333901
lublicalioos Fire Ratcd and moke Outlet Ducrwork An Industry Guide t Design and InSlalla lioll
HEALTH AND SAFETY EXEC TIVE Rose Court 2 Southwark Bridge London SEl 9HS Telephone 020-7717 6000
TWJ THE WELD G TlTUTE Abington Hall Abington Cambridge CB16AL Telepbone 0 J223 89162
Publication DatJ Oil w~ldll1g of lhermopla lics
59
DW154 wciiwlioll for Plastics Ductwork
A -=--DIX
Factors
Specific gravity shy pp = 091 approx UPVC = 14 approx
Some miscellaneous conversion factors
To convert
Length Inches to millimetres Feet to metres
Multiply by
2540 03048
To convert
Millimetres to inches Metres to feet
vIultiply by
003937 3281
Area Square inches to square millimetres 6452 Square millimetres to square inches 000155 Square feet to square metres 00929 Square metres to square feet 10764
Volume Cubic feet to cubic metres Cubic feet to litres Gallons (UK) to litres
002832 2831 4546
Cubic metres to cubic feet Litres to cubic feet Litres to gallons (UK)
35315 00353
022
Mass Ounces to grams Pounds to kiJograms Tons to tonnes
2835 04536
1016
Grams to ounces Kilograms to pounds Tonnes to tons
003527 2205
09842
Volume flow Cubic feet per minute to cubic Cubic metres per second to cubic
metres per second 0000472 feet per minute 2119 Cubic feet per mIDute to litres Litres per second to cubic feet
per second 04719 per minute 2119
Motion Feet per minute to metres per second 000508 Metres per second to feet per minute 197
Pressure Inches water gauge to millibars 2491 Inches wateJ- gauge to pascals (Pa) 2491 I Pa = I ewton per square metre = 10-2 millibars
60
Heating and Ventilating Contractors Association Esca House 34 Palace Court London W2 4JG
Tel 020 7313 4900
e-mail contact Itvcaorguk web site wwwhvcaorguk
Fax 020 7727 9268
DW154 Speciicfltirm for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - REC ~NGULAR
Splilt~r Posilion W-mm pliucr
A B c 40]--QOO 1 W - -
601-1000 1 W4 Wf2 -
1001-1800 3 WI W3 W2
FIG DRAWING DETAfiS
tU]36 ATI Straight Duct with socket and spigol joint
rn [037 Straight Duct with flanged joints
[I []38 Straight Duct with flanged joints
rkJ Short Radius Bend
39 Applies to any augl and for duct up to 400 n11n wide
Minimum (I1m31 radills = 100 mm
Medium Radius Bend (a illustrated)
[kJ Applies to any angle
40 Long Radiu Bend Similar but radius = W
Throlll radius = W2 Applies to any angle
- Short Radius Bend with plitlers
I -shy -shy u co - t lt Li--_ 41 t 0 ~ I I I
~ I
L 1W
Minimum waal radius = 100 mm Splitters not required in bend angle less than 45deg
42 QJ1 Square Bend with turning vanes ij
3
DW154 SP(L~ficatioll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - RECTANGULAR
FIG DRAWl G DETADS
43
~
I v
L L Radius Tee with internal deflectors
44
~ Radiussed Twin Bend
45
Imiddot
er Swept Branch
46 U-
Sqoare Tee with Turning Vanes
47
~ f
Breeches Piece
48 0 y l Piece
34
DW154 Specificatioll for Plastics Ductwork
STANDARD COMPONENT RAWINGS - ECTANGULAR
55
54
51
50
53
52
49
FIG
~MX
RAWlNG
DmiddotMAX
EfjMAX
Minimum throat rndius = 100 mm
Rectangular shy Round Transformatioll
Eccentric Taper 225deg max in either plane Spliller are required for angles greater than 225deg and hould bi eet the angle between any side and duct centreline
DETATLS
Angled Offset
OUset Taper Splitters are required for angle greater than 22 0
and shoold bi eet the angl between any side and dUCI centrelinc
Mitred Offset
Concentrk Taper 2250 max in ither plane SpUtters are required for angle greater than 225deg and should bisect the angle between any side and duel c ntreline
Radiussed Offset
35
DW154 Splcilcuthm for Plastics Ductwork
STANDARD COMPONENT DRAWINGS ~ RECTANGU AR
Branch ducl DimCllsions widlh (W) (A)
urnl mm up lO 200 75
300 100 400 125 600 150
Ocr 600 200
FIG DRAWlNG DETAILS
56 poundplusmni~~ Rectan~lar - Flat Oval Transformation
57 [ Square Branch
58 er Angled Branch
Branch dUCI Dimensions wfdth (W) (A)
[- mm mm59 3shy Shoe Branch Up (0 200 75
--shy AIshy + 300 100
400 125
450 MAX 600 150
Over 600 200
Branch duct DimensIOn
rP X width (W) A)
60 - 1--shy _
~ mm mm
Bell Mouth Branch pto 200 75 300 100 t 400 125
600 150 Over 600 200
0=0 61 -
~ Bell Mouth
- shy T 4-5deg M x
--I 1-shy
TJ
62 X I ] I
Tele-scopic Joint I Illustrated with flangeL
X63
SBD Single Bladed Damper
36
---
DW154 Spedicatioll for Plastics Ductwork
STANDARD OMPONENT DRAWINGS - RECTANGULAR
DRAWING DETAILSFIG
64 on-Return DamperNRD shyshy
shyXbull
Multi-Leaf Damper Can be piggoted or flanged oppo cd or parallel blade
Alternative controls areshy
q p [gtshy
J HD65 Hand
~MD otori ed
PO Pneumalic
L-lt
l 13G 66 Blast Gate DamperX X
FireSmoke DampersSleeves
211r Ratinggtshy----
L_-
---
----
r----
Ir-- shy
IL- _-l
2hr
With i tallation frame
67 41 r Rating
4hr
Smoke damper SD
Intumc cent Sleeve L-d
37
DW154 Specijicutiolt for Plastics Ductwork
FIG
68
69
70
71
STANDARD COMPONET DRAWINGS shy REC ANGULAR
DRAVING DETAILS
gtshy Access Openings
AP 6 Access Panel - Rerno able
w [ ~ Access Door - Hinged
I ~le Inspection Cover
le -I reg -lt
~X X Flexible Connection
~ Drop Cheeked Radiussed Twin Bend
U Drop Cheek Bend
I
72 Air Flow SymbolX
38
DW154 Specifim[ioll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - ECTANGULAR
FIG DRAWING DETAILS
73
74
75
76
77
Q
Q
rp---t
~
V- I Ir---I
JL --11
THE ABOVE DETAILS TYPICAL PLENUM
Air Terminal Plenums
Plenum with side connection
Plenum with top connection
Cover plate with connection
Special plenum with connection
elescopic conn ction in direction of air flow
39
DW154 SpecijicotiOll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG
78
79
80
81
DRAWING
-23~---pound3-(MALE) (FEMAJE)
-t=j--_j(--d-shy
--L
~ THROAT RADI S= D AS T NDARD
e ~
THROAT Rjf)lU = D A MU)
DETAILS
Straight Duct With male and female connectors
Straight Duct With flange joint and slip joint
Bend MouldedIFormed Applies to any angle ego 30deg45deg60deg90deg Medium radius bend as illustrated Long radius similar but throat radius 0
Segmented Bend 90deg four section minjmum as illustrated
Other Angles 60deg = 3 sections 45deg = 3 sections 30deg = 2 sections
I
i
40 shy
DW154 Speciicafinll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG DRAWING DETAlLS
82 Segmented Twin Bend Radius = D2 max
May also be fabricated from tube
83 Equal Tee MouldedIFormed
84 -~ 1in Bend MouldedIFormed
85 Taper Concentric 1 0 as iUu trated Eccentric 30deg iJJcLuded angle
86 Short Taper
41
DW154 SpcUicatol1 for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG DRAWING DETAILS
87 30 max Offset
Angle Branch
Bran h dUCI Dimcnsions dia (D) lA)
Shoe Branch mm mm 88 Cl
Off rectanguJur Up 10 200 75 lOO 10 400 125
- 00 150 Over 600 200
Bl1IllCh duct DimenlOns din (D) (A
~-$a-Conical Branch mm mm
89 Also acceptable with Up 10 200 r
full conical surface 300 10
400 125
END VrE -shy 600 150 Over 600 200
90
m 75
100 12 150 200
mm Up to 200
_ 300 400
600 Over 600
iUtred Branch
Shoe Branch
J-L----U ~ Bell oulh Branch
ENDV1EW
93
92
91
42
DW154 Specificatiol for Plastics Ductwork
STANDARD OMPONENT DRAWINGS - CIRCULAR
FIG
94
DRAW G
I
~ 30deg 090deg
Breeches Piece
DETAILS
95 amp-----~ Blank End
~-----p Multi-Leaf Damper Can be piggolcd or fianged opposed or parallel blade
Alternative controls areshyri=-+- L-T~
I
---
LT~
I r- -
-+1
J HO Hand96
bMD Molori cd
PD Pneumatic
tl-shy bull
Single Bladed Damper 97 ~ saD
on-Return Damper Vertical application only 98 m~D
43
DW154 Sf1tcificatioll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG
99
100
101
102
DRAWING
$ I-
2hr
1 4hr
SD
~v I I
CO TINENTAL COWL
DETAILS
Iris Damper
Fi reS moke Dam persSleeves
2hr Ratillg
With installation frame
4br Rating
Smoke damper
Intumescent Sleeve
Access Openings
Access panel - removable
Access door shy hinged
fnspection cover
Discharge Continental Cowl
44
DW154 Sp(Cii(ltJll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
DRAWINGltIC DETAns
-
I
I
~
I I I High Velocity Discharge Terminal 103 I
I
I I
J I I 1 ~--
Offset Stack Discbarge Terminal 104 1
~ I e --(-
I
N
I
I
I~
I I Vertical Oischarge with Weather Cowl 105 I
--1--1 I
I
GAPI I
RTl AL DISC) lARGE WITH W ATIIER COWL
45
DW154 SpecUicatoll for Plastics Ductwork
STANDARD COMPONE T DRAWINGS - PLA TEQUIPMENTIMISCELLANEOU
FIG DRAWING DETAILS
106 ~~~ Rectangular Attenuator
107 ~- Circular Attenuator
108
~ Beod Attenuator
109 J ~(f) Heating Coil
110 J ftte Cooling Coil
III Jc[ Electric Heating Coil
112 X F
Humidifier
113 [H XX Axial Fan
114 ~fB1famp Noo-standard Ductwork Cross hntchillg (of any separate type) indicates by reference to a key any non DVil54 ductwork system
115 2llIIIIJIIIIIll Flexible Ductwork
46
DW154 SJeCUicll(iol1 for Plastics Ductwork
TABLE 12 - STANDARD ABBREVIAT ONS
ABBREVIATION FLL
AD Acces Door
AFF Axial Flow Fan
AHU Air Handling nit
All Aluminium
AP Acess Panel
AT Attenuator
AV Air enninal Unit
BE 81ank nd
BQ Blast ate Damper
CC Cooling Coil
CF Centrifugal Fan
CTA Cross alk Attenuator
CVU Constant Volume Unit
DP Drain Point
EEC Electric Heating Coil
El Expansion Joint
FAl Fresh Air Inlet
FA From Above
FB From Belo
fBPP Fabric Backed Polypropyl-ne Sheet
Flexle Flexible Connection
lexfD Flexible Du t
C False Ceiling CO an oil Unit
fD Fire Damper
FFL Finished Floor Level
FJ Flanged Joint
FOAM Rigid Polyurethane Self xtinguishing Foam
FOB Flat on Bottom
FOT Flat on Top
GAM Galvanised after ManufacttrJc
GRP Glass Reinforced Plastic
GSS Galvanised Sheet Steel
HC Heating oil
HD and controlled Damper
HH Hand Hole
HL High Level
HVD High Velocity Discharge
IC Inspection Cover
ID lri Damper
IFS Intumescent Fircleevc
47
DW154 Specification for Plastics Ductwork
TABLE 12 - STANDAR ABBREVIATION CONTINUED
ABBREVIATION
IU
L
tv1D
MS
NRD NTS
OBO
OE
PHD
PD
PP
PP
PRD
PVC
RFC
RSC
R
SBO
SO
S1 TST
SSL
TA
TB
TO TJ
TP
TV
TV
OS
UPVC
S
V
VAV
50 RSA
FULL
Induction Unit
Low Level
Motor controlled Damper
Mjld Steel
on Return Damper
at to cale
Opposed Blade Damper
Open End
Parallel Blade Damper
Pneumatic controlled Damper
Polypropylene
Self xtinguishing Polypropylene
Pressure Relief Damper
Polyvinyl Chloride
Rolled Form Chamlel
Rolled Steel Channel
R fUnit
Singl Blade Damper
Smoke Damper
Slip Joint
Stainl t el
tructural Slab Level
To Ab vc
To Blow
Top Down (In Direction of Flow)
Telescopic Joint
Test Point
TU111iog Vane
Top Up (In Direction of Flo )
Voles Otherwise Stated
Unpl3sticisecl Polyvinyl Chloride
Underside
Ultra Violet Light
Variable Air Volume
Rolled Steel Angle (Vith Size)
48
DW154 SJeriiflllioll for Plastics Ductwork
A2 DUCT PRESSUREAPPE DXA Ductwork con truct d to DWIl54 will bebullbullbullbullbullbullbullbullbullbullbullbullbullbull
Air Leakage From Ductwork To be read in conjunction with DW143 A practical guide to Ductwork Leakage Testing
CAUTION As highlighted ill both this docul1lenr and DW14 I lot ellough emphasis can be placed 01 the fact that except for high pressure class C the much more stringent ductwork constructional standard brolght about b the general acceptance of DW154 have irtlally negated the requirement for leakage-testing It is essential lO realise lhat except where it is mandatory this doclllllelll is nOl an endors ~lIlent of the rourine testing of ducts bllt purely a guide to outline the procedures for cononnity with the air leakage limits ill Table l Where the specified methods of assembly and
A3sealing of dlcls are u ed a vi ual inspection wil ordinarily sl~fll e for ver(iatioll of a well engineered and a ceptahfy airtight COl1strucrioll WHERE NOT MANDATORY DUCT LEAKAGE TESTING IS GENERALLY AN UNJUSTIFIED AND SUBSTANTIAL EXPENSE
A1 INTRODUCTION L akage from ducted air distribution systems is an Lmportant consideration in the design and operation of ventilatjon and air conditioning middotystems A ductviork t)ystem tbat ba limited air leakag within defiucd limits wiH cnsUft
that tile design characteristics of the sytem can be maintained It wilJ also ensure that energy and operatLonal cosb are maintained at optimum levels DucLwork constlucted and Ulstalled in accordance with DW154 should minimise a level of air leakage that it) appropriate to tll operating static air pre sur in tile system
A4However it is recouuised that tbe environment in wtJich middotystems are installed is not always conducive to achieving a predictable level of quality in term of system ajr leakage and it is therefore accepted that designer may sometimes require tlle ystem to be tested in part or in total It should be ecogni ed that the testing of duct systems add a ignificant cost to the installation and incur some extra tjm within the programme (Se 47 and 64 re mandatory te-sting)
manufactured to a structural standard that is compatible with the system operating pressure There are three classes of duct con truction to eorre pond with the three pre ure clas meations Class A Lo pressure ducts suita le for a maximum positive operating pressure of 500 Pascal and a maximum negative pressure of -500 Pascals Class B IVledium pressure ductmiddot suitable for a rnaxilnuJJl positive operafjn o pressure of 1000 Pascals and a maxllnum negative pre sure of -750 Pa cal Class C High pre sure ducts suitable for a maximum po ilive operating pressur of 2000 Pa cals and a maximum negativ pres ur of -750 Paltcals
LEAKAGE FROM DUCTWORK Leakao-e front pia tic air ducts occur at the joint~ and is therefore proportional to the total surface area orthe du twork in th system Tb level of leakage i imilarly related to tIle air pres ure in th du t system and whilst there LS n precis formula for calculating the level of air los it i generally accepted that leakage will increase in proportjon to pressure to rbe pOvver of 065 The effect of air leakage from high pressure velocit ductwork is critical tn terms of system perfomlan dege energy consumption and the risk of high frequency noise as ociated with leakage These problems are le critical with medium pressure 10 ity systems but should be con idered Low pres mevelocity ducts present the lowe~t
ri k in tenn of tbe effect of leakage on the operation of the s stern
SYSTEM LEAKAGE LOSS As there i no di ct relatLonship between th volume of air conv yed and the surface area f the ductwork sy tern required to match the building configuratmn it is difficult to express air leakage a a percentage of total air volume Similarly the operating pressure will vary throughollt lh 3 system and a leakage is related to pre me the calculations ar comple However it is generally ac epted tbat in typical good quaJjty systems the leakage from
49
DW154 Specificatioll for Plastics Ductwork
each class of duct llnd r operating condition will be io the region of CIa S A low pressure 6 Clas B medium pres un 3 Clas C high pressure 2
A5 SPECIFYING AIR LEAKAGE TESTING Re peeting both the co -t and programme implications a sociated with te ling du 1 for leakage the designer may for example indicate that a particular system is te ted as follow
a) High pressure ducts - all tested b) Medium pr ssure duets - 10 of the
ductwork shall be s eet d at random and tested
c) Low pre sure - unte ed In any case where a random te t i elected for medium pre sure ductmiddot the followin c1au~e is suggested for inclusion by the de ign r
The designer hall elect at random a maxirnwlI of 10 of the dUCl system to bt tested for air leakage The duct hall be tested af the pressure recommended in Table J3 for the assifi atiol for the ectiol1 of the ductwork that is to be tested The tests shall be carried Ollt as the work proceeds and prior to the application of thermal insulation In the event of test failure of the randomlY selected section the designer shall have The right to select two La1her e tiolls at random for resting Where succes ive failures are identified there shall be a Tight to require rhl COl11raCWr 10 apply remedial attention to the complete ductwork system Th contractor shall provide documented eviden e of the calculalions used to arrive (1
the allowable 10 I for the section to be tested and the client or his agent shall willess and sign the results of the test
able 13 Air leakage rates
Maximum leakage of duct work Static
prcssUft Low-pressure edium-prc-sure I Iigh-prebull me diJfercntial Class A Class B Class C
1 2 J 4 Pa Litres per second per quare metre of surface area 100 054 018 ZOO 084 028 300 110 037 400 132 044 500 153 051 600 058 019 700 064 021 800 069 023 900 075 025
1000 080 027 1100 1200 1300 1400 1500
029 030 032 033 035
1600 1700 1800 1900 2000
036 038 039 040 042
Note Recommend d mean test presures are highlighted iD bold type with the actual selection being left to tll test operator
50
DW154 Sfeeiieaioll for Plastics Ductwork
A9
A10
and air leakage classification for the y em under test
DESIGNERS CALCULATIONS The designer can middotaJculate with reasonable accuracy the predicted total loss from a ystem by
a) Calculating the operatin presure in each ection of the sy tern
b) Calculating the surface area of the ductwork in each correspondin pre lire s ction
c) Calulating the allowabl~ los at the operating pressure for each ection of the system (see table 13 for allowable leakage figures)
VARIABLE PRESSUR S IN SYSTEMS De igner can achieve significant co t saving by matchina operating pressures throughout the system to constmctional standard and appropriate air leakage testing eO the practice of specifying construction tandards for whole duct sy tems based on fan discharge pre sure may incur unnece sary costs on a project For example ome large sy terns ould well be classiC ed for I akage limits as follows
Plant room risers CJas C Main floor distriblltJou CIa B Low pre sure outlets Cla A
A6 SPECIAL CASES There may be ~itLlations on a project where circumstance dictate thal pecial consideration be given to containing air loss s eg a long mn of duclwork may incur a di -proportjonate level of air 10 s In ca es such as thi example the designer can specify an improved tandard of airtighmess ie 80 of alJo~able 10 s for la B Ju ts The designer sbould not specif a CIa C t sI at CIa s C pressure for a CIa s B ducl
A7 SUGG S ED RANGE OF TES ING
A8 TESTING OF PLANT ITEMS Items of inline pJant (eg Fig 106 to 115) will not normaUy be included in an air I akage test The dllctwork contractor may indud such itelllS in tbe te t jf rh quipm ot has a certificate of COnfOlnlity for Ihe pres ure clas
bull High pressure duct bull Medium pre sure ducts bull Low pre sur ducts bull Exposed extract syst ID bull Ceiling void extract
systems bull Secondary ducts from
VAV or fan coil units bull Flexjble duct bull Final connections and
branches to grille and diffusers
100 test See A5 Untested UDt sted
Untested
Untested Untested
Untested
SI
i
DW154 SJecijicafion for Plastics Ductwork
ig 116 Permitted leakage at various pressures
Leakage in litres per second per square metre duct surface area
Vgt
o ltgt 0 ltgt N
ltgt Cgt
0 0 cc
0 0
~
g =
g ~
c 0
J
ltgt 0 I
~ ] tn
ltgt ltgt
In ol
~ 0 ~ 8 ~
~
c ltgt ltgt
~ CJ
~ ~ ~ ~ 8
0shyij
~ ~ ~ t
ltgt ltgt 00
l
~
~ Q
c C
~ rshy
e ltgt
I 1
I Cgt ltgtv
c Co ~
~~ ~ 10
I
0 Cgt
fJshyq 410 ) 1 ltgt
ltgt N
~ shy ltgt ltgt
~ I 1
c
52
DW154 Specificatio for Plastics Ductwork
Example of a completed test sheet Test No
General
Name of job N~ jC43Pt(r2lef Building Repound ~(~~0
Part 1 - Physical details
a Section of duct work to be tested ~(diffPIfff~el1f3rd Floor
b Drawing Number g91~~ c ssure aSSJ L atlOn V~Jl~IRfYgtg~~lPre Cl T Class C
d Test static pressure -(9 raErq~ ~~~~-~~J~~~ ~~ ~~~~ll
Leakaoe factor 9~-tre3$ecMz I OM REFTOTABLE 13)e b bullbullbullbullbullbullbull
f Surface area of duct under test Q~tJJItetre$ CPROMCALCU TIO BELOW)bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull ampampamp bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull
g ]Vlaxi mum permitted leakage -~ (~i~~0 ~~r~~ ~~~l-~-11~ ~~~Q
Part 2 - Test particulars
a Duct static pressure reading 9QFt~q~ ~ middot~~~1 ~~
b Manufacturer and type of liow measuring d vice (-~~~cJ~Y-9Q7EYg c Range of measurement of now measuring device QtP)OQ~(e~~~0I~~~~1~I~ ~~~~~~W~
d Reading of flm measurin o device pmiddot IFROM RIO)ftscag ~
I (DERlVED [ROM CHART SUPPUED WITH RIG US 0 ud)1e Interpreted air flow leakage rate ~(~~~f~~~ (~l~~~~~~~~~~~~~~~~~I
f Duration ~~~~~norn~allY l~ lnil1Ut~~d~~~ it1~ W~ Date of test ~(lITled ut by Wltll s ed by ~ ~
(~lJ MIJLrr) (Si~rrfltJUYJ
Printed Name 1~g0f~ Printed Name ~~Y~9~ and Company 7jl~~~~~( UJd CompanY AB COII$Itallt8
Width and depth or diameter
Periphery ength Area
millimetreS millimetres metre qL1are metre
800 x 750 3100 1755 5440
600 x 650 2500 557 1193
300 x 300 1200 120 144
305 din 958 700 670
250 dia 785 450 353
TOTAL 8000
53
DW154 Specijilarion for Plastics Ductwork
pA XB
Guida ce No es For he ransport Handling and
Storage of uctwork
avoid damage to adjacent duct panels In somc ca es particularly on con acts calling f r repetitive sizes the use of timber jigs and spacers may be justified Where reduced bulk and greater protection are major factor such as consignments for export transporting ductwork in L shape sections may justify the increa ed ite as embly co ts
It is recommended that before a contract is finalised that consideration is given to the subject of site acces material handling and storage as tbcy havgt a strong influence on the cost efficiency of the overall activity of ductwOlk installation
B3 Handling To minilnise th risk of damage duct sections should be clearly identified and deliveries to site should be closely linked to the installation programme so as to avoid accumulation of
B1 Storage and Handling of Ra Material Material should be stored in suitably designed racking out of direct unJight Where possible the e racks should be metal to earth Edges of cut she t may be harp and protective gloves are advised Wearing teel toe-capped boots is recommended Most pIa tic sheet is manufactured with smootb mfaces andor is suppLied with protective coating Care must be taken to prevent accidental lippag of stacked materials Beiuoshy good electrical insulators the movement of stock unless earthed will allow the build up of stati All stock shapes are chemically stable at normal temperature Whil t some raw materials used in their manufacture may themselves pre ent a toxic hazard once incorporated into the lOck bape they no long r constitute such a hazard and no dermatitic bazard are known nor are any
unfiJied ductwork and minimise double handling It is important to recognise that ductwork panels joint and corners arc susceptible to damage and care must be taken wheu band ling such material through a site During handling individual item of duct work may be liable to light cross sectional deformation until thev become an integral pan of a completed ductwork system Whilst this may temporarily detract from its intended appearance thi deformation will not have any detrimental effect on the functionality of the finally a semblecl system Installation of duct work and asociated plant items ill illevitably involve manual handUng The responsibi Iiry of employers and employees to a ses the risk of personal injury during mallual handling operations is et out in the HS E publication L23 Guidance on Manual Handling Regulations 1992
environmental problems expected 84 Site storage
B2 fransport Large capacity vehicles with high-sided open or closed-top bodies are tlle mo t suitable for the transport of dllctwork Careful consideration should be given to the
Adequate floor space IDust be provided within tbe building for the site storage of ductvork Such storage shalt make due allowance for thc stOf(ne of ductwork in stacks such that access ~ egt
between them is of sufficient width to pennil the removal of item without interference to
unloading of transport on sit a not all siJes b n fit from the material handlino- and access facilities that exi [ in a manufacturing workshop such as crane- fork-lifts or loading bay Site handJiog facilities along with
adjoining sta ks Ductvork components should be positioned so a to avoid crushing Ductwork of small panel size may be stored horizontally however care should be exercised to ensure that tack sizes are limited 10 within
ehicular acce s restrictions may itilluence the type and ize of transport to be uWised
engtlls of ductwork should be positioned 0
the tmctural strength of the duct sections to prevent distortion of the lower sections within the stack
as to avoid crushing Lengths Witll projections such as branches and bends i1anges girths damper quadrauL should be loaded so as to
54
DW154 S1tciic(ltioll for Plastics Ductwork
85 Internal cleanliness of new ductwork The site storage of ductwork introduces the important cODsideration of maintaining the internal cleanliness of the ductwork R feren e should be made to HVCA documentshybull DWffM2 Guide to Good Practice - internal
Cleanliness of New Ductwork Installations If the above conditioDs can not be satisfied consideration should be given by tJle designer to amending the specification to include for Po t Installation Cleaning as covered by tJ1C HVCA documentshybull TRJ17 Guide to Good Practic - Cleanliness
of Ventilation Systems
APPE DIXC
Fi e Retardant inishes C1 Improvement in the fire retardancy of plastic
ducts can be achieved to varying degrees and is wholly dependent llPOll the surface coating laminating resin selected and construction specification adopted In some instances smoke emission is coILSidered equaUy with other speci fication requirernen ts of the materials resistance to ignition and bumjng It is therefore important for design rs to establ ish the clients and officers detailed requirements and not rely on a tbird party interpretation of fire resisting or fire retardant Where possible the specification should refer dir etly to compliance with a British or European Standard identifying the specific sections applicable There are various types of resin and mat rcLnforcements that can achieve a Class 1 surface spread of flame ratin o when tested according to BS476 Part 7 (1987) This test puts materials illto Class I - 4 in descending order of perfoDllance according to the rat and extent of flame spread over their surfac under standard beating conditions Materials should also be tested for flre propagarion to BS476 Part 6 (1989) Tbi tesr measures the amount and rate of heat evolved by the material when subjected to standard heating
conditions Test results are given as an index of Perfonnance (i) whicb is based on three sub indices (iJ (i1) (h) The higher the value of the Index of Performance (i) the greater is the material s contribution to fire growth The higher the value of the sub-index 0) rhe greater the ease of ignition aod flame spread The highest product performance classification as defined in Approved Document B of the Building Regulations is Class O This is acLlieved if a material surface of a composite ploduct i~ either a) composed throughout of materials of
limited combustibility or b) a Class I material which has a tlre
propagation index (i) of not more than 12 and sub-index (i l ) of nor more than 6
01 J Class 0 is not a cla$sif1cation identified in any British Standard test
There are resin system reported to be classified to Class O when tested to BS476 Pcl1S 6 and 7 however designers need to ensure that such sysrems can be applied to their proposed design In propriety resinmat system available the fabrication techniques and COITect application are critical to the integrity of the reinforcing and clas ificatiol1 For example in some systems the u e of a non-fire retardant gelcont on a fire retardant substrate would reduce the classification For further information see HVCA publication DW144 Appendix D
55
DW154 SplCijiClIliol1 for Plastics Ductwork
x Guidance otes For nspectmiddoton Servicing a d
Clean-ng Access Openings
D1 GE ERAL This appendix highlight in ummary fOI111
the acce considerations that hould be made by the design r iD terms of inspection servicing and cleaning Having considered the seop and the design of the dUCI work system relative to the guidelines outlined below the designer should clearly indicate which levels of acces should be incorporated into the manufacture of a new duct work system (See Table 14 and Note I b low it
D2 DESIGN CONSIDERATIONS
D21 In ptction and servicing requireshyments are set out in Section 15 of Lhis specification
D22 Cleaning requirements are set out in the HVCA pubUcation TRl7 Guide to Good Practice Clean Lines of Ventilation Systems and the guide tates The precise location ize and
type of access would be dependent on the type of ductwork cleaning inspection and te ting metbods to b adopted Care protection and standards of cleanliness prior LO cOlllmisionin o
are set out in th AV A publication DWITM2 Guide to Good Practice Internal Cleanliness of New Ductwork Installations and th guide state Wh re specific limits of cleanliness are required ductwork sball be cleaned after installation by a spcialist cleaning contractor It will b in the interests of tht desioner botb financially and practically to cunsider employing a specialist c1eauing contractor at tbe
outset of a contract to internally clean newly installed ductwork prior to bandover This approach would reali e the following benefit shyi) Tb actual numb r of cleaning
access panels could be detennined to suit the method of cleaning to be adopted (This may be 1 s than the maximum requiremen listed under Lev 13 of Table 14)
ii) Clear directions could b given to the ductwork contractor as to tJle size and location of cleaning access panels that are required to be fitted during the mauushyfaclunng pro s
iii) The specialist cleaning operation prior to commi ioning vould enable the cleaning contractor to verify the practical acee requirement for the future cleaning operation associated -vitb a regular maintenance programme
iv) A specialist cleaning operation prior to commissioning would allow the designer to omit from the speeilicatiolJ the DWrrM2 requirem nt for factory sealing protection wipe downs and capping-off
v) Specialist Ieall ill 0 to the measurable standard defin d in TR17 will allow an objective definition of cleanline to be achieved
Car ful consideration must be gIven by the designer to the practl aJ problems associated witb the manufacture and fitting of suitably si Led access panel on small cross section duct and on the circular faces of rouod and flat oval ducts in particular
D23 Special con ideration must be given by the de igner to the practical problems associated with gaining personnel access to heavily congested ceiling areas and multi-la red du twork systems This approach would avoid
56
DW154 Spfciication for Plastics Ductwork
the possibility of access panels being D3 ACCESS 0 IN-LINE EQUIPMENT incorporated into a ductwork system at the This appendix unly covers acc il1spection manufacturing stage that were later found in through the ductwork body adjacent to an item practice to be inaccessible for either ervicing of in-line equipment and not openings in the or cleaning activities equipment itself
able 14 Acce requirements for inspection servicing and cleaning
HVCA PUBLICATIO REFE NeE (uidtgt 10 Gund Prartict
Adjace t OW144 Cleanliness orVcnlillltio S~lcr~ fRjJ7
in-line LeyeJ 1 Level 2 Level 3 ite sequipment pcdionSen lcin~ Section d C1eaniJl( SUn(O)lnspc lion Palle ltk~m_n
2011 (minimum OiL Jubje-ct to duct ~zel (ft~ -Panels
Control Da pcrs One (inspection) 203 One 300 mm x 200 mm Both sid Fire Dampers One (sCTjdJl~) 20211 One 300 0101 x 200 mm One side HeatingCooling Coils One (inspedion) 20213 One 300 mm x 200 mm (lIpstream) Both sides Attenuators (rectangular) None required One 300 mm x 200 mm (downstream) Both sides Attenuators (circular) one retluired One 300 mm x 200 mm (downstream) One side Filter Sections One (inspection) 20212 one required Uoth sides Air Turn Vanes None requjred None required Both sides Changes of Direction None required one required One side In-Duct FansDevices One (inspection) 20213 None required Both sides l
1 In the absence of any indication by the designer only Level ) access will be jncorporated into a new ductwork system
2 Tbe panel izes associated with Lev lis I and 3 acee s ar e middottablished by reference to Section 20 of DW144 and Section 2 ofTRll7 respectively
57
DW154 Speclfifatio for Plastics Ductwork
pA XE
B-bliography Included in this Bibliography are technical pUblications which may be of interest (0 ductwork designers fabricators and erectors and to tho e in the heating ventilatlng air conditioning industries generally nquiric should be made of the relevant organisation at the address quoted Since its publication other addresse contained within 0V154 mav have changed and some pubJicalions may have been superseded
HEATING AND VENTILATING CONTRACTORS ASSOCIATION
4 Palace Court London W2 4JG Telephone 020-7229 2488 Fax 020-7727 9268
Orders fo FlY A Publications Old Matlsion House Eamont Bridge Penrith Cumbria CA 10 2BX (Telephone 01768 864771 Fax 01768 86718) Email hvcapoblicationshvwelfarecouk DWn 44 pe ilicatiun for sheet mctal duclwork (Iow- mediulllshy
and high-pressure) 1998) DWIl4 A practical guide to dUGI ork I akage te ting
(revised 2000) DWII54 Specification for plastic~ duct rk DW171 Guide to good Practice for kitchen venlibtion system DW191 Guide to good pracuce glass fibre ductwoJk DwrrMI Acceptance cheme for new products - Redangolar cro
joint classification Guide to good pra tice - Internal cleanliness of new ductwork installations Guide to good practice for the design for the Installation of lire and smoke uampers
J 1Other puhlications
HampV safely guide 5th edition JS2 Tool box talks JS5 Weldlng Safety booklet JSI9 afety facts bo klet Fact sheets 1-24 2nd edition JS2J COSHH manual volume 1 Advice on compliance with the
regulations 1521A CO I-rH manual volume 2 Asses mcnt h ets JS23 Ri k management manual TR3 BrazinltT and bronze welding of copper pipework cUld sheet
(I 976) TR5 Welding of carbon steel pipework (1980)
TR6 Guide to Good Practice for Site Pre sure Testing of Pipework (19 0) Guide to good practice cleanliness of ventilation Ylem
CHARTERED IN TITUTlO OF BUILDING SERVICES E G EERS Delta House 222 Balham High Road London SW12 9BS rTelephone 020-8675 5211 Fax 020-8675 5449) CIBSE Guide Volume A Design Data Volume B In tallatiol1 and quipment Data Volume C Reference Data
CommlssioniJIg Codes These Codes eover the preliminary checkS eUing to work and regulation of vanous catcgories 0 plan The Codes give a guide to design implications Series A Air Distnbution Systems Series B Boiler Plant
ri s C Automatic Conlrol ystems Cr1es R Refrigerating Sy terns
Sene iN Water Distribution Systems
Technkal Memonllda TM 4 Design Notes for the Middle East TM bull Design otes for Ductwork TM 13 Minimi iog lhc Risk of egiounaires Disease
Research Reports RROI95 Ventilation system hygiene - A review of published
infomlatioo on lhe occurrence and ffects of Olltamination Rl~02J95 Air-to-air heal rec v ry RR0395 rnfluen e of HV C on smoke detectors
ATlONAL ENI [ERING SPECIFICATION LfMITED Southgatc hamber 3739 Southgate Street Winchester S023 9EH (Telephone 01962 842058 Fax 01962 R(8982) BUfLDING S RVICES RESEARCH AND [ ORMATION ASSOCIATIO Old Bracknell Lane West Bracknell Berkshire RG 12 4AH (Telephone Brackl1eU (01344) 426511 Fax 01344 487 -7 )
Application Guides AGln4 De tglJing Vana~le Volume middotylans for KOOnl
iir Movement AG1I91 Commissioning of V Sylcms in Buildings 11 6194 Fire Dampers
B) 94 cntiJalion or KitcneTls
AG389 The Commls ionin of Air Systems In Buildmgs AH2192 Commissioning of Bern - A ~ode of Practice TN2417 I Fire Dampec il) Ventilating Ducl
BEATING VENTILATING A AIR CONDITION G MA UFACTURERS ASSOCIATIO (HEVAC) HEVAC Henley Road Medmenham Marlow Buck SU 2ER (Telephone 01491 578674 ox 01491 575024 Emoimiddot infofetacouk)
Publicatjons Air Diffusion Guide Guide to Air Handling Unit Leakage Testing Guide to Good Practice Air Handling Unit Real Room Acoustic ~ st Procedure Specification for the ertiiicatioll ofAir Filters Method of Test for Water Rejection PerfOnTlatce of Louvrcs Subjected 1(1
Simulated Rainfall Test Procedure for Acoustic Loo cs Specification 10 Floor GrilJes - Types Performan e and Method ofTest Specification for the Determination of the Collection Efficiency of SilJ1d
Trap Louvre Domestic Mechwlical Vclltllalion Systems with Heal Recovery Fan Application Guid
~an and Ouctwork Installation Guide Guide to Fan Noise and Vibration
pecification of Requirements for JallJral Smoke and Heal Exhausl Ventilators
pecification for Powered Smoke and Heat Exhaust Ventilators
Specification of Requirements for Smoke Curtains Design Gujue of Smoke Ventilation for Single Storey Lodustrilll Building~
Including those with Mezzanine Floor and IIi Racked Storage Warehou es - Issue 3
Guidance for the Design of Smoke entilation YSlem for Covered and Undergrollnd Car Parks - lssue 1
Application of SOloke Control Equipment and Syst m Guid to Good Practice - Isue J
58
DW154 Sp(C~tiifitiol for Plastics Ductwork
BRITISH STANDARDS INSTIT TION Sales Department 101 P ntooviLle Road London NI 9ND (felephone 020-78 1 78801)
CP 413 1973 Ducts for building ervices
SS 476 Fire tes on building matenals and lruc(ure
Part 4 19 4 Non-combustibility lest or materials
Part 6 I Fire propagation lest for materials
Part 7 1993 Surface spread of tlarnJ tesls for materia
Part 20 1987 Fir resistance of elements of construction
Part 21 1987 Fire r sistlUlce of loadbeanng elements of construction
Part 22 1987 Fhe istallceofllon-loadbearing elemcllts ofconsttuclion Part 23 1987 Contribution of componcnts to the fire resistance 0 a
structure
Part 24t987 Fire resi lance of wl1lilation ductl
SS 5588 nan 919 0 Fire Precautions III thc desIgn and OOSlnJ lion of buildings
S 729 1971 Hot dip galvanized oatiugs (or irOIl aod stcel articles
BS 1449 Steel plate sheet and Irip
Pan 11991 Carbon steel plate heel and strip Part 2 1983 Stainless steel plate sheer and strip
and
B middotENJOI49-2 996 BSEN 10149- 1991)
BSEN 10131 1992
BSEN22063 Sprayed metal coarings 1994 Protection of iron and steel by aluminium and zinc against
atmospheric cOlosion Irotectiotl of iron and ste I against corro ion and oxishydation at elevared temperatures
BS 353 1981 Glossary of lerms relnting to thermal insulation
BS ISO 1479 Self-tapplngscrewsandmetallicdri c crew
B -lSO 7049
1994
B 4800 1989 Painl colour for building purposes B 4848 l0 rolled structural steel sections
Part4 1972 Equal and unequal angles BS 5422 1990 Specification for the use of therm illuating matcriulS
SS 5720 1979 ode of practice for mechanical veutilating and air C 11shy
dirionin bull in building
l3S PR 12814-1 Bend resting for plasric welds
SS PR 12814-2 Tensile testing for plastic welds
SS PR 13067 Appro altesting for plastic welds
BS PR EN I 100-] Vi ual in pection ofplaslic welds
SHEET METAL AND AIR CONDITIONING CONTR-CTORS NATIONAL ASSOCIATION INC (SMACNA) Headquarters 420 I Lafayeue Center Drive Chanlilly Virginia 2051-1209
Mailing Address pa Box 221230 Cbantilly Virginilt120 153-1230
Telephone (703) 803-2980 Fax (703) 803-3732
Accepted IJJdustry Pl3Gtice for Industrial Duct Constnlelion 197 ) i-rchitecmral Sheet kwl Manual ([993)
Comractors Guide lor Modification 10 ooslruerion Colllraets 1993 Ducted Eleclric Heat Guide for ir Handling Ssrerns (1994)
En~rgy ollservatioD Guidelines (1984) Energy Recovery Equipment yslClllS (199l
Fibrou GIns Duct onS1ntClion Standards (1992)
Fire Smoke amp Radiation Damper In tall Guide for HVA Syst ms (1992) Guide t leel Stack 1(95)
HVA Air Duct Leakage Test Manual (19 ) HVA COlllmissioning lvlanual (1994)
H A Duct Construction Standards-Metal amp Flexible (1995) Addendum 01 (Nov 1997)
HVA Duct Systems Inspection Guide (1989)
HVA ySlems-Application (1986) nVAC ByternS-DLlct D ign (1990)
HVi Systems-Testing Adjusting amp Balancing (1993)
indoor Air Quality Manual (1993) tcheu quipment Fabrication Guidelmes (1990)
Managers Guide for elding (1993)
Rectangular Industrial Duct Cons1TUction Standards (19 0) Round Industrial Duct oustmction Standards (1977)
Sei mic Restraint Manual (1991) (wl Appendix E 1993) SMACNA Ma le Index ()fTechnical Publications (1995) Tbennoplnstic Duct CPY ) Construction Manual 1994)
DEPARTME OF THE ENVIRO MENT (Publications Centre) H Stationery Oflice 5 Nine Elms Lane London SWS 5DR
MampEJ 011972 Electrical in tallat1011 in buildings ( ew Editiou)
IampE 0319 Healing hot and cold wat r steam and gas losla1lations for buildings
M amp - No4 1970 Central heating and hot and cold ~ ateT in tallations for
dwelling
M amp ENo100 1971 Mechanical ventilation for building~
ASSOCIATION FOR SPECIALIST FIRE PROTECTlO As ociation House 235 Ash Road AJdershot Hampshire GUl2 4DD
Telephone OJ25221322 Fax 0 J252 333901
lublicalioos Fire Ratcd and moke Outlet Ducrwork An Industry Guide t Design and InSlalla lioll
HEALTH AND SAFETY EXEC TIVE Rose Court 2 Southwark Bridge London SEl 9HS Telephone 020-7717 6000
TWJ THE WELD G TlTUTE Abington Hall Abington Cambridge CB16AL Telepbone 0 J223 89162
Publication DatJ Oil w~ldll1g of lhermopla lics
59
DW154 wciiwlioll for Plastics Ductwork
A -=--DIX
Factors
Specific gravity shy pp = 091 approx UPVC = 14 approx
Some miscellaneous conversion factors
To convert
Length Inches to millimetres Feet to metres
Multiply by
2540 03048
To convert
Millimetres to inches Metres to feet
vIultiply by
003937 3281
Area Square inches to square millimetres 6452 Square millimetres to square inches 000155 Square feet to square metres 00929 Square metres to square feet 10764
Volume Cubic feet to cubic metres Cubic feet to litres Gallons (UK) to litres
002832 2831 4546
Cubic metres to cubic feet Litres to cubic feet Litres to gallons (UK)
35315 00353
022
Mass Ounces to grams Pounds to kiJograms Tons to tonnes
2835 04536
1016
Grams to ounces Kilograms to pounds Tonnes to tons
003527 2205
09842
Volume flow Cubic feet per minute to cubic Cubic metres per second to cubic
metres per second 0000472 feet per minute 2119 Cubic feet per mIDute to litres Litres per second to cubic feet
per second 04719 per minute 2119
Motion Feet per minute to metres per second 000508 Metres per second to feet per minute 197
Pressure Inches water gauge to millibars 2491 Inches wateJ- gauge to pascals (Pa) 2491 I Pa = I ewton per square metre = 10-2 millibars
60
Heating and Ventilating Contractors Association Esca House 34 Palace Court London W2 4JG
Tel 020 7313 4900
e-mail contact Itvcaorguk web site wwwhvcaorguk
Fax 020 7727 9268
DW154 SP(L~ficatioll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - RECTANGULAR
FIG DRAWl G DETADS
43
~
I v
L L Radius Tee with internal deflectors
44
~ Radiussed Twin Bend
45
Imiddot
er Swept Branch
46 U-
Sqoare Tee with Turning Vanes
47
~ f
Breeches Piece
48 0 y l Piece
34
DW154 Specificatioll for Plastics Ductwork
STANDARD COMPONENT RAWINGS - ECTANGULAR
55
54
51
50
53
52
49
FIG
~MX
RAWlNG
DmiddotMAX
EfjMAX
Minimum throat rndius = 100 mm
Rectangular shy Round Transformatioll
Eccentric Taper 225deg max in either plane Spliller are required for angles greater than 225deg and hould bi eet the angle between any side and duct centreline
DETATLS
Angled Offset
OUset Taper Splitters are required for angle greater than 22 0
and shoold bi eet the angl between any side and dUCI centrelinc
Mitred Offset
Concentrk Taper 2250 max in ither plane SpUtters are required for angle greater than 225deg and should bisect the angle between any side and duel c ntreline
Radiussed Offset
35
DW154 Splcilcuthm for Plastics Ductwork
STANDARD COMPONENT DRAWINGS ~ RECTANGU AR
Branch ducl DimCllsions widlh (W) (A)
urnl mm up lO 200 75
300 100 400 125 600 150
Ocr 600 200
FIG DRAWlNG DETAILS
56 poundplusmni~~ Rectan~lar - Flat Oval Transformation
57 [ Square Branch
58 er Angled Branch
Branch dUCI Dimensions wfdth (W) (A)
[- mm mm59 3shy Shoe Branch Up (0 200 75
--shy AIshy + 300 100
400 125
450 MAX 600 150
Over 600 200
Branch duct DimensIOn
rP X width (W) A)
60 - 1--shy _
~ mm mm
Bell Mouth Branch pto 200 75 300 100 t 400 125
600 150 Over 600 200
0=0 61 -
~ Bell Mouth
- shy T 4-5deg M x
--I 1-shy
TJ
62 X I ] I
Tele-scopic Joint I Illustrated with flangeL
X63
SBD Single Bladed Damper
36
---
DW154 Spedicatioll for Plastics Ductwork
STANDARD OMPONENT DRAWINGS - RECTANGULAR
DRAWING DETAILSFIG
64 on-Return DamperNRD shyshy
shyXbull
Multi-Leaf Damper Can be piggoted or flanged oppo cd or parallel blade
Alternative controls areshy
q p [gtshy
J HD65 Hand
~MD otori ed
PO Pneumalic
L-lt
l 13G 66 Blast Gate DamperX X
FireSmoke DampersSleeves
211r Ratinggtshy----
L_-
---
----
r----
Ir-- shy
IL- _-l
2hr
With i tallation frame
67 41 r Rating
4hr
Smoke damper SD
Intumc cent Sleeve L-d
37
DW154 Specijicutiolt for Plastics Ductwork
FIG
68
69
70
71
STANDARD COMPONET DRAWINGS shy REC ANGULAR
DRAVING DETAILS
gtshy Access Openings
AP 6 Access Panel - Rerno able
w [ ~ Access Door - Hinged
I ~le Inspection Cover
le -I reg -lt
~X X Flexible Connection
~ Drop Cheeked Radiussed Twin Bend
U Drop Cheek Bend
I
72 Air Flow SymbolX
38
DW154 Specifim[ioll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - ECTANGULAR
FIG DRAWING DETAILS
73
74
75
76
77
Q
Q
rp---t
~
V- I Ir---I
JL --11
THE ABOVE DETAILS TYPICAL PLENUM
Air Terminal Plenums
Plenum with side connection
Plenum with top connection
Cover plate with connection
Special plenum with connection
elescopic conn ction in direction of air flow
39
DW154 SpecijicotiOll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG
78
79
80
81
DRAWING
-23~---pound3-(MALE) (FEMAJE)
-t=j--_j(--d-shy
--L
~ THROAT RADI S= D AS T NDARD
e ~
THROAT Rjf)lU = D A MU)
DETAILS
Straight Duct With male and female connectors
Straight Duct With flange joint and slip joint
Bend MouldedIFormed Applies to any angle ego 30deg45deg60deg90deg Medium radius bend as illustrated Long radius similar but throat radius 0
Segmented Bend 90deg four section minjmum as illustrated
Other Angles 60deg = 3 sections 45deg = 3 sections 30deg = 2 sections
I
i
40 shy
DW154 Speciicafinll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG DRAWING DETAlLS
82 Segmented Twin Bend Radius = D2 max
May also be fabricated from tube
83 Equal Tee MouldedIFormed
84 -~ 1in Bend MouldedIFormed
85 Taper Concentric 1 0 as iUu trated Eccentric 30deg iJJcLuded angle
86 Short Taper
41
DW154 SpcUicatol1 for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG DRAWING DETAILS
87 30 max Offset
Angle Branch
Bran h dUCI Dimcnsions dia (D) lA)
Shoe Branch mm mm 88 Cl
Off rectanguJur Up 10 200 75 lOO 10 400 125
- 00 150 Over 600 200
Bl1IllCh duct DimenlOns din (D) (A
~-$a-Conical Branch mm mm
89 Also acceptable with Up 10 200 r
full conical surface 300 10
400 125
END VrE -shy 600 150 Over 600 200
90
m 75
100 12 150 200
mm Up to 200
_ 300 400
600 Over 600
iUtred Branch
Shoe Branch
J-L----U ~ Bell oulh Branch
ENDV1EW
93
92
91
42
DW154 Specificatiol for Plastics Ductwork
STANDARD OMPONENT DRAWINGS - CIRCULAR
FIG
94
DRAW G
I
~ 30deg 090deg
Breeches Piece
DETAILS
95 amp-----~ Blank End
~-----p Multi-Leaf Damper Can be piggolcd or fianged opposed or parallel blade
Alternative controls areshyri=-+- L-T~
I
---
LT~
I r- -
-+1
J HO Hand96
bMD Molori cd
PD Pneumatic
tl-shy bull
Single Bladed Damper 97 ~ saD
on-Return Damper Vertical application only 98 m~D
43
DW154 Sf1tcificatioll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG
99
100
101
102
DRAWING
$ I-
2hr
1 4hr
SD
~v I I
CO TINENTAL COWL
DETAILS
Iris Damper
Fi reS moke Dam persSleeves
2hr Ratillg
With installation frame
4br Rating
Smoke damper
Intumescent Sleeve
Access Openings
Access panel - removable
Access door shy hinged
fnspection cover
Discharge Continental Cowl
44
DW154 Sp(Cii(ltJll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
DRAWINGltIC DETAns
-
I
I
~
I I I High Velocity Discharge Terminal 103 I
I
I I
J I I 1 ~--
Offset Stack Discbarge Terminal 104 1
~ I e --(-
I
N
I
I
I~
I I Vertical Oischarge with Weather Cowl 105 I
--1--1 I
I
GAPI I
RTl AL DISC) lARGE WITH W ATIIER COWL
45
DW154 SpecUicatoll for Plastics Ductwork
STANDARD COMPONE T DRAWINGS - PLA TEQUIPMENTIMISCELLANEOU
FIG DRAWING DETAILS
106 ~~~ Rectangular Attenuator
107 ~- Circular Attenuator
108
~ Beod Attenuator
109 J ~(f) Heating Coil
110 J ftte Cooling Coil
III Jc[ Electric Heating Coil
112 X F
Humidifier
113 [H XX Axial Fan
114 ~fB1famp Noo-standard Ductwork Cross hntchillg (of any separate type) indicates by reference to a key any non DVil54 ductwork system
115 2llIIIIJIIIIIll Flexible Ductwork
46
DW154 SJeCUicll(iol1 for Plastics Ductwork
TABLE 12 - STANDARD ABBREVIAT ONS
ABBREVIATION FLL
AD Acces Door
AFF Axial Flow Fan
AHU Air Handling nit
All Aluminium
AP Acess Panel
AT Attenuator
AV Air enninal Unit
BE 81ank nd
BQ Blast ate Damper
CC Cooling Coil
CF Centrifugal Fan
CTA Cross alk Attenuator
CVU Constant Volume Unit
DP Drain Point
EEC Electric Heating Coil
El Expansion Joint
FAl Fresh Air Inlet
FA From Above
FB From Belo
fBPP Fabric Backed Polypropyl-ne Sheet
Flexle Flexible Connection
lexfD Flexible Du t
C False Ceiling CO an oil Unit
fD Fire Damper
FFL Finished Floor Level
FJ Flanged Joint
FOAM Rigid Polyurethane Self xtinguishing Foam
FOB Flat on Bottom
FOT Flat on Top
GAM Galvanised after ManufacttrJc
GRP Glass Reinforced Plastic
GSS Galvanised Sheet Steel
HC Heating oil
HD and controlled Damper
HH Hand Hole
HL High Level
HVD High Velocity Discharge
IC Inspection Cover
ID lri Damper
IFS Intumescent Fircleevc
47
DW154 Specification for Plastics Ductwork
TABLE 12 - STANDAR ABBREVIATION CONTINUED
ABBREVIATION
IU
L
tv1D
MS
NRD NTS
OBO
OE
PHD
PD
PP
PP
PRD
PVC
RFC
RSC
R
SBO
SO
S1 TST
SSL
TA
TB
TO TJ
TP
TV
TV
OS
UPVC
S
V
VAV
50 RSA
FULL
Induction Unit
Low Level
Motor controlled Damper
Mjld Steel
on Return Damper
at to cale
Opposed Blade Damper
Open End
Parallel Blade Damper
Pneumatic controlled Damper
Polypropylene
Self xtinguishing Polypropylene
Pressure Relief Damper
Polyvinyl Chloride
Rolled Form Chamlel
Rolled Steel Channel
R fUnit
Singl Blade Damper
Smoke Damper
Slip Joint
Stainl t el
tructural Slab Level
To Ab vc
To Blow
Top Down (In Direction of Flow)
Telescopic Joint
Test Point
TU111iog Vane
Top Up (In Direction of Flo )
Voles Otherwise Stated
Unpl3sticisecl Polyvinyl Chloride
Underside
Ultra Violet Light
Variable Air Volume
Rolled Steel Angle (Vith Size)
48
DW154 SJeriiflllioll for Plastics Ductwork
A2 DUCT PRESSUREAPPE DXA Ductwork con truct d to DWIl54 will bebullbullbullbullbullbullbullbullbullbullbullbullbullbull
Air Leakage From Ductwork To be read in conjunction with DW143 A practical guide to Ductwork Leakage Testing
CAUTION As highlighted ill both this docul1lenr and DW14 I lot ellough emphasis can be placed 01 the fact that except for high pressure class C the much more stringent ductwork constructional standard brolght about b the general acceptance of DW154 have irtlally negated the requirement for leakage-testing It is essential lO realise lhat except where it is mandatory this doclllllelll is nOl an endors ~lIlent of the rourine testing of ducts bllt purely a guide to outline the procedures for cononnity with the air leakage limits ill Table l Where the specified methods of assembly and
A3sealing of dlcls are u ed a vi ual inspection wil ordinarily sl~fll e for ver(iatioll of a well engineered and a ceptahfy airtight COl1strucrioll WHERE NOT MANDATORY DUCT LEAKAGE TESTING IS GENERALLY AN UNJUSTIFIED AND SUBSTANTIAL EXPENSE
A1 INTRODUCTION L akage from ducted air distribution systems is an Lmportant consideration in the design and operation of ventilatjon and air conditioning middotystems A ductviork t)ystem tbat ba limited air leakag within defiucd limits wiH cnsUft
that tile design characteristics of the sytem can be maintained It wilJ also ensure that energy and operatLonal cosb are maintained at optimum levels DucLwork constlucted and Ulstalled in accordance with DW154 should minimise a level of air leakage that it) appropriate to tll operating static air pre sur in tile system
A4However it is recouuised that tbe environment in wtJich middotystems are installed is not always conducive to achieving a predictable level of quality in term of system ajr leakage and it is therefore accepted that designer may sometimes require tlle ystem to be tested in part or in total It should be ecogni ed that the testing of duct systems add a ignificant cost to the installation and incur some extra tjm within the programme (Se 47 and 64 re mandatory te-sting)
manufactured to a structural standard that is compatible with the system operating pressure There are three classes of duct con truction to eorre pond with the three pre ure clas meations Class A Lo pressure ducts suita le for a maximum positive operating pressure of 500 Pascal and a maximum negative pressure of -500 Pascals Class B IVledium pressure ductmiddot suitable for a rnaxilnuJJl positive operafjn o pressure of 1000 Pascals and a maxllnum negative pre sure of -750 Pa cal Class C High pre sure ducts suitable for a maximum po ilive operating pressur of 2000 Pa cals and a maximum negativ pres ur of -750 Paltcals
LEAKAGE FROM DUCTWORK Leakao-e front pia tic air ducts occur at the joint~ and is therefore proportional to the total surface area orthe du twork in th system Tb level of leakage i imilarly related to tIle air pres ure in th du t system and whilst there LS n precis formula for calculating the level of air los it i generally accepted that leakage will increase in proportjon to pressure to rbe pOvver of 065 The effect of air leakage from high pressure velocit ductwork is critical tn terms of system perfomlan dege energy consumption and the risk of high frequency noise as ociated with leakage These problems are le critical with medium pressure 10 ity systems but should be con idered Low pres mevelocity ducts present the lowe~t
ri k in tenn of tbe effect of leakage on the operation of the s stern
SYSTEM LEAKAGE LOSS As there i no di ct relatLonship between th volume of air conv yed and the surface area f the ductwork sy tern required to match the building configuratmn it is difficult to express air leakage a a percentage of total air volume Similarly the operating pressure will vary throughollt lh 3 system and a leakage is related to pre me the calculations ar comple However it is generally ac epted tbat in typical good quaJjty systems the leakage from
49
DW154 Specificatioll for Plastics Ductwork
each class of duct llnd r operating condition will be io the region of CIa S A low pressure 6 Clas B medium pres un 3 Clas C high pressure 2
A5 SPECIFYING AIR LEAKAGE TESTING Re peeting both the co -t and programme implications a sociated with te ling du 1 for leakage the designer may for example indicate that a particular system is te ted as follow
a) High pressure ducts - all tested b) Medium pr ssure duets - 10 of the
ductwork shall be s eet d at random and tested
c) Low pre sure - unte ed In any case where a random te t i elected for medium pre sure ductmiddot the followin c1au~e is suggested for inclusion by the de ign r
The designer hall elect at random a maxirnwlI of 10 of the dUCl system to bt tested for air leakage The duct hall be tested af the pressure recommended in Table J3 for the assifi atiol for the ectiol1 of the ductwork that is to be tested The tests shall be carried Ollt as the work proceeds and prior to the application of thermal insulation In the event of test failure of the randomlY selected section the designer shall have The right to select two La1her e tiolls at random for resting Where succes ive failures are identified there shall be a Tight to require rhl COl11raCWr 10 apply remedial attention to the complete ductwork system Th contractor shall provide documented eviden e of the calculalions used to arrive (1
the allowable 10 I for the section to be tested and the client or his agent shall willess and sign the results of the test
able 13 Air leakage rates
Maximum leakage of duct work Static
prcssUft Low-pressure edium-prc-sure I Iigh-prebull me diJfercntial Class A Class B Class C
1 2 J 4 Pa Litres per second per quare metre of surface area 100 054 018 ZOO 084 028 300 110 037 400 132 044 500 153 051 600 058 019 700 064 021 800 069 023 900 075 025
1000 080 027 1100 1200 1300 1400 1500
029 030 032 033 035
1600 1700 1800 1900 2000
036 038 039 040 042
Note Recommend d mean test presures are highlighted iD bold type with the actual selection being left to tll test operator
50
DW154 Sfeeiieaioll for Plastics Ductwork
A9
A10
and air leakage classification for the y em under test
DESIGNERS CALCULATIONS The designer can middotaJculate with reasonable accuracy the predicted total loss from a ystem by
a) Calculating the operatin presure in each ection of the sy tern
b) Calculating the surface area of the ductwork in each correspondin pre lire s ction
c) Calulating the allowabl~ los at the operating pressure for each ection of the system (see table 13 for allowable leakage figures)
VARIABLE PRESSUR S IN SYSTEMS De igner can achieve significant co t saving by matchina operating pressures throughout the system to constmctional standard and appropriate air leakage testing eO the practice of specifying construction tandards for whole duct sy tems based on fan discharge pre sure may incur unnece sary costs on a project For example ome large sy terns ould well be classiC ed for I akage limits as follows
Plant room risers CJas C Main floor distriblltJou CIa B Low pre sure outlets Cla A
A6 SPECIAL CASES There may be ~itLlations on a project where circumstance dictate thal pecial consideration be given to containing air loss s eg a long mn of duclwork may incur a di -proportjonate level of air 10 s In ca es such as thi example the designer can specify an improved tandard of airtighmess ie 80 of alJo~able 10 s for la B Ju ts The designer sbould not specif a CIa C t sI at CIa s C pressure for a CIa s B ducl
A7 SUGG S ED RANGE OF TES ING
A8 TESTING OF PLANT ITEMS Items of inline pJant (eg Fig 106 to 115) will not normaUy be included in an air I akage test The dllctwork contractor may indud such itelllS in tbe te t jf rh quipm ot has a certificate of COnfOlnlity for Ihe pres ure clas
bull High pressure duct bull Medium pre sure ducts bull Low pre sur ducts bull Exposed extract syst ID bull Ceiling void extract
systems bull Secondary ducts from
VAV or fan coil units bull Flexjble duct bull Final connections and
branches to grille and diffusers
100 test See A5 Untested UDt sted
Untested
Untested Untested
Untested
SI
i
DW154 SJecijicafion for Plastics Ductwork
ig 116 Permitted leakage at various pressures
Leakage in litres per second per square metre duct surface area
Vgt
o ltgt 0 ltgt N
ltgt Cgt
0 0 cc
0 0
~
g =
g ~
c 0
J
ltgt 0 I
~ ] tn
ltgt ltgt
In ol
~ 0 ~ 8 ~
~
c ltgt ltgt
~ CJ
~ ~ ~ ~ 8
0shyij
~ ~ ~ t
ltgt ltgt 00
l
~
~ Q
c C
~ rshy
e ltgt
I 1
I Cgt ltgtv
c Co ~
~~ ~ 10
I
0 Cgt
fJshyq 410 ) 1 ltgt
ltgt N
~ shy ltgt ltgt
~ I 1
c
52
DW154 Specificatio for Plastics Ductwork
Example of a completed test sheet Test No
General
Name of job N~ jC43Pt(r2lef Building Repound ~(~~0
Part 1 - Physical details
a Section of duct work to be tested ~(diffPIfff~el1f3rd Floor
b Drawing Number g91~~ c ssure aSSJ L atlOn V~Jl~IRfYgtg~~lPre Cl T Class C
d Test static pressure -(9 raErq~ ~~~~-~~J~~~ ~~ ~~~~ll
Leakaoe factor 9~-tre3$ecMz I OM REFTOTABLE 13)e b bullbullbullbullbullbullbull
f Surface area of duct under test Q~tJJItetre$ CPROMCALCU TIO BELOW)bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull ampampamp bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull
g ]Vlaxi mum permitted leakage -~ (~i~~0 ~~r~~ ~~~l-~-11~ ~~~Q
Part 2 - Test particulars
a Duct static pressure reading 9QFt~q~ ~ middot~~~1 ~~
b Manufacturer and type of liow measuring d vice (-~~~cJ~Y-9Q7EYg c Range of measurement of now measuring device QtP)OQ~(e~~~0I~~~~1~I~ ~~~~~~W~
d Reading of flm measurin o device pmiddot IFROM RIO)ftscag ~
I (DERlVED [ROM CHART SUPPUED WITH RIG US 0 ud)1e Interpreted air flow leakage rate ~(~~~f~~~ (~l~~~~~~~~~~~~~~~~~I
f Duration ~~~~~norn~allY l~ lnil1Ut~~d~~~ it1~ W~ Date of test ~(lITled ut by Wltll s ed by ~ ~
(~lJ MIJLrr) (Si~rrfltJUYJ
Printed Name 1~g0f~ Printed Name ~~Y~9~ and Company 7jl~~~~~( UJd CompanY AB COII$Itallt8
Width and depth or diameter
Periphery ength Area
millimetreS millimetres metre qL1are metre
800 x 750 3100 1755 5440
600 x 650 2500 557 1193
300 x 300 1200 120 144
305 din 958 700 670
250 dia 785 450 353
TOTAL 8000
53
DW154 Specijilarion for Plastics Ductwork
pA XB
Guida ce No es For he ransport Handling and
Storage of uctwork
avoid damage to adjacent duct panels In somc ca es particularly on con acts calling f r repetitive sizes the use of timber jigs and spacers may be justified Where reduced bulk and greater protection are major factor such as consignments for export transporting ductwork in L shape sections may justify the increa ed ite as embly co ts
It is recommended that before a contract is finalised that consideration is given to the subject of site acces material handling and storage as tbcy havgt a strong influence on the cost efficiency of the overall activity of ductwOlk installation
B3 Handling To minilnise th risk of damage duct sections should be clearly identified and deliveries to site should be closely linked to the installation programme so as to avoid accumulation of
B1 Storage and Handling of Ra Material Material should be stored in suitably designed racking out of direct unJight Where possible the e racks should be metal to earth Edges of cut she t may be harp and protective gloves are advised Wearing teel toe-capped boots is recommended Most pIa tic sheet is manufactured with smootb mfaces andor is suppLied with protective coating Care must be taken to prevent accidental lippag of stacked materials Beiuoshy good electrical insulators the movement of stock unless earthed will allow the build up of stati All stock shapes are chemically stable at normal temperature Whil t some raw materials used in their manufacture may themselves pre ent a toxic hazard once incorporated into the lOck bape they no long r constitute such a hazard and no dermatitic bazard are known nor are any
unfiJied ductwork and minimise double handling It is important to recognise that ductwork panels joint and corners arc susceptible to damage and care must be taken wheu band ling such material through a site During handling individual item of duct work may be liable to light cross sectional deformation until thev become an integral pan of a completed ductwork system Whilst this may temporarily detract from its intended appearance thi deformation will not have any detrimental effect on the functionality of the finally a semblecl system Installation of duct work and asociated plant items ill illevitably involve manual handUng The responsibi Iiry of employers and employees to a ses the risk of personal injury during mallual handling operations is et out in the HS E publication L23 Guidance on Manual Handling Regulations 1992
environmental problems expected 84 Site storage
B2 fransport Large capacity vehicles with high-sided open or closed-top bodies are tlle mo t suitable for the transport of dllctwork Careful consideration should be given to the
Adequate floor space IDust be provided within tbe building for the site storage of ductvork Such storage shalt make due allowance for thc stOf(ne of ductwork in stacks such that access ~ egt
between them is of sufficient width to pennil the removal of item without interference to
unloading of transport on sit a not all siJes b n fit from the material handlino- and access facilities that exi [ in a manufacturing workshop such as crane- fork-lifts or loading bay Site handJiog facilities along with
adjoining sta ks Ductvork components should be positioned so a to avoid crushing Ductwork of small panel size may be stored horizontally however care should be exercised to ensure that tack sizes are limited 10 within
ehicular acce s restrictions may itilluence the type and ize of transport to be uWised
engtlls of ductwork should be positioned 0
the tmctural strength of the duct sections to prevent distortion of the lower sections within the stack
as to avoid crushing Lengths Witll projections such as branches and bends i1anges girths damper quadrauL should be loaded so as to
54
DW154 S1tciic(ltioll for Plastics Ductwork
85 Internal cleanliness of new ductwork The site storage of ductwork introduces the important cODsideration of maintaining the internal cleanliness of the ductwork R feren e should be made to HVCA documentshybull DWffM2 Guide to Good Practice - internal
Cleanliness of New Ductwork Installations If the above conditioDs can not be satisfied consideration should be given by tJle designer to amending the specification to include for Po t Installation Cleaning as covered by tJ1C HVCA documentshybull TRJ17 Guide to Good Practic - Cleanliness
of Ventilation Systems
APPE DIXC
Fi e Retardant inishes C1 Improvement in the fire retardancy of plastic
ducts can be achieved to varying degrees and is wholly dependent llPOll the surface coating laminating resin selected and construction specification adopted In some instances smoke emission is coILSidered equaUy with other speci fication requirernen ts of the materials resistance to ignition and bumjng It is therefore important for design rs to establ ish the clients and officers detailed requirements and not rely on a tbird party interpretation of fire resisting or fire retardant Where possible the specification should refer dir etly to compliance with a British or European Standard identifying the specific sections applicable There are various types of resin and mat rcLnforcements that can achieve a Class 1 surface spread of flame ratin o when tested according to BS476 Part 7 (1987) This test puts materials illto Class I - 4 in descending order of perfoDllance according to the rat and extent of flame spread over their surfac under standard beating conditions Materials should also be tested for flre propagarion to BS476 Part 6 (1989) Tbi tesr measures the amount and rate of heat evolved by the material when subjected to standard heating
conditions Test results are given as an index of Perfonnance (i) whicb is based on three sub indices (iJ (i1) (h) The higher the value of the Index of Performance (i) the greater is the material s contribution to fire growth The higher the value of the sub-index 0) rhe greater the ease of ignition aod flame spread The highest product performance classification as defined in Approved Document B of the Building Regulations is Class O This is acLlieved if a material surface of a composite ploduct i~ either a) composed throughout of materials of
limited combustibility or b) a Class I material which has a tlre
propagation index (i) of not more than 12 and sub-index (i l ) of nor more than 6
01 J Class 0 is not a cla$sif1cation identified in any British Standard test
There are resin system reported to be classified to Class O when tested to BS476 Pcl1S 6 and 7 however designers need to ensure that such sysrems can be applied to their proposed design In propriety resinmat system available the fabrication techniques and COITect application are critical to the integrity of the reinforcing and clas ificatiol1 For example in some systems the u e of a non-fire retardant gelcont on a fire retardant substrate would reduce the classification For further information see HVCA publication DW144 Appendix D
55
DW154 SplCijiClIliol1 for Plastics Ductwork
x Guidance otes For nspectmiddoton Servicing a d
Clean-ng Access Openings
D1 GE ERAL This appendix highlight in ummary fOI111
the acce considerations that hould be made by the design r iD terms of inspection servicing and cleaning Having considered the seop and the design of the dUCI work system relative to the guidelines outlined below the designer should clearly indicate which levels of acces should be incorporated into the manufacture of a new duct work system (See Table 14 and Note I b low it
D2 DESIGN CONSIDERATIONS
D21 In ptction and servicing requireshyments are set out in Section 15 of Lhis specification
D22 Cleaning requirements are set out in the HVCA pubUcation TRl7 Guide to Good Practice Clean Lines of Ventilation Systems and the guide tates The precise location ize and
type of access would be dependent on the type of ductwork cleaning inspection and te ting metbods to b adopted Care protection and standards of cleanliness prior LO cOlllmisionin o
are set out in th AV A publication DWITM2 Guide to Good Practice Internal Cleanliness of New Ductwork Installations and th guide state Wh re specific limits of cleanliness are required ductwork sball be cleaned after installation by a spcialist cleaning contractor It will b in the interests of tht desioner botb financially and practically to cunsider employing a specialist c1eauing contractor at tbe
outset of a contract to internally clean newly installed ductwork prior to bandover This approach would reali e the following benefit shyi) Tb actual numb r of cleaning
access panels could be detennined to suit the method of cleaning to be adopted (This may be 1 s than the maximum requiremen listed under Lev 13 of Table 14)
ii) Clear directions could b given to the ductwork contractor as to tJle size and location of cleaning access panels that are required to be fitted during the mauushyfaclunng pro s
iii) The specialist cleaning operation prior to commi ioning vould enable the cleaning contractor to verify the practical acee requirement for the future cleaning operation associated -vitb a regular maintenance programme
iv) A specialist cleaning operation prior to commissioning would allow the designer to omit from the speeilicatiolJ the DWrrM2 requirem nt for factory sealing protection wipe downs and capping-off
v) Specialist Ieall ill 0 to the measurable standard defin d in TR17 will allow an objective definition of cleanline to be achieved
Car ful consideration must be gIven by the designer to the practl aJ problems associated witb the manufacture and fitting of suitably si Led access panel on small cross section duct and on the circular faces of rouod and flat oval ducts in particular
D23 Special con ideration must be given by the de igner to the practical problems associated with gaining personnel access to heavily congested ceiling areas and multi-la red du twork systems This approach would avoid
56
DW154 Spfciication for Plastics Ductwork
the possibility of access panels being D3 ACCESS 0 IN-LINE EQUIPMENT incorporated into a ductwork system at the This appendix unly covers acc il1spection manufacturing stage that were later found in through the ductwork body adjacent to an item practice to be inaccessible for either ervicing of in-line equipment and not openings in the or cleaning activities equipment itself
able 14 Acce requirements for inspection servicing and cleaning
HVCA PUBLICATIO REFE NeE (uidtgt 10 Gund Prartict
Adjace t OW144 Cleanliness orVcnlillltio S~lcr~ fRjJ7
in-line LeyeJ 1 Level 2 Level 3 ite sequipment pcdionSen lcin~ Section d C1eaniJl( SUn(O)lnspc lion Palle ltk~m_n
2011 (minimum OiL Jubje-ct to duct ~zel (ft~ -Panels
Control Da pcrs One (inspection) 203 One 300 mm x 200 mm Both sid Fire Dampers One (sCTjdJl~) 20211 One 300 0101 x 200 mm One side HeatingCooling Coils One (inspedion) 20213 One 300 mm x 200 mm (lIpstream) Both sides Attenuators (rectangular) None required One 300 mm x 200 mm (downstream) Both sides Attenuators (circular) one retluired One 300 mm x 200 mm (downstream) One side Filter Sections One (inspection) 20212 one required Uoth sides Air Turn Vanes None requjred None required Both sides Changes of Direction None required one required One side In-Duct FansDevices One (inspection) 20213 None required Both sides l
1 In the absence of any indication by the designer only Level ) access will be jncorporated into a new ductwork system
2 Tbe panel izes associated with Lev lis I and 3 acee s ar e middottablished by reference to Section 20 of DW144 and Section 2 ofTRll7 respectively
57
DW154 Speclfifatio for Plastics Ductwork
pA XE
B-bliography Included in this Bibliography are technical pUblications which may be of interest (0 ductwork designers fabricators and erectors and to tho e in the heating ventilatlng air conditioning industries generally nquiric should be made of the relevant organisation at the address quoted Since its publication other addresse contained within 0V154 mav have changed and some pubJicalions may have been superseded
HEATING AND VENTILATING CONTRACTORS ASSOCIATION
4 Palace Court London W2 4JG Telephone 020-7229 2488 Fax 020-7727 9268
Orders fo FlY A Publications Old Matlsion House Eamont Bridge Penrith Cumbria CA 10 2BX (Telephone 01768 864771 Fax 01768 86718) Email hvcapoblicationshvwelfarecouk DWn 44 pe ilicatiun for sheet mctal duclwork (Iow- mediulllshy
and high-pressure) 1998) DWIl4 A practical guide to dUGI ork I akage te ting
(revised 2000) DWII54 Specification for plastic~ duct rk DW171 Guide to good Practice for kitchen venlibtion system DW191 Guide to good pracuce glass fibre ductwoJk DwrrMI Acceptance cheme for new products - Redangolar cro
joint classification Guide to good pra tice - Internal cleanliness of new ductwork installations Guide to good practice for the design for the Installation of lire and smoke uampers
J 1Other puhlications
HampV safely guide 5th edition JS2 Tool box talks JS5 Weldlng Safety booklet JSI9 afety facts bo klet Fact sheets 1-24 2nd edition JS2J COSHH manual volume 1 Advice on compliance with the
regulations 1521A CO I-rH manual volume 2 Asses mcnt h ets JS23 Ri k management manual TR3 BrazinltT and bronze welding of copper pipework cUld sheet
(I 976) TR5 Welding of carbon steel pipework (1980)
TR6 Guide to Good Practice for Site Pre sure Testing of Pipework (19 0) Guide to good practice cleanliness of ventilation Ylem
CHARTERED IN TITUTlO OF BUILDING SERVICES E G EERS Delta House 222 Balham High Road London SW12 9BS rTelephone 020-8675 5211 Fax 020-8675 5449) CIBSE Guide Volume A Design Data Volume B In tallatiol1 and quipment Data Volume C Reference Data
CommlssioniJIg Codes These Codes eover the preliminary checkS eUing to work and regulation of vanous catcgories 0 plan The Codes give a guide to design implications Series A Air Distnbution Systems Series B Boiler Plant
ri s C Automatic Conlrol ystems Cr1es R Refrigerating Sy terns
Sene iN Water Distribution Systems
Technkal Memonllda TM 4 Design Notes for the Middle East TM bull Design otes for Ductwork TM 13 Minimi iog lhc Risk of egiounaires Disease
Research Reports RROI95 Ventilation system hygiene - A review of published
infomlatioo on lhe occurrence and ffects of Olltamination Rl~02J95 Air-to-air heal rec v ry RR0395 rnfluen e of HV C on smoke detectors
ATlONAL ENI [ERING SPECIFICATION LfMITED Southgatc hamber 3739 Southgate Street Winchester S023 9EH (Telephone 01962 842058 Fax 01962 R(8982) BUfLDING S RVICES RESEARCH AND [ ORMATION ASSOCIATIO Old Bracknell Lane West Bracknell Berkshire RG 12 4AH (Telephone Brackl1eU (01344) 426511 Fax 01344 487 -7 )
Application Guides AGln4 De tglJing Vana~le Volume middotylans for KOOnl
iir Movement AG1I91 Commissioning of V Sylcms in Buildings 11 6194 Fire Dampers
B) 94 cntiJalion or KitcneTls
AG389 The Commls ionin of Air Systems In Buildmgs AH2192 Commissioning of Bern - A ~ode of Practice TN2417 I Fire Dampec il) Ventilating Ducl
BEATING VENTILATING A AIR CONDITION G MA UFACTURERS ASSOCIATIO (HEVAC) HEVAC Henley Road Medmenham Marlow Buck SU 2ER (Telephone 01491 578674 ox 01491 575024 Emoimiddot infofetacouk)
Publicatjons Air Diffusion Guide Guide to Air Handling Unit Leakage Testing Guide to Good Practice Air Handling Unit Real Room Acoustic ~ st Procedure Specification for the ertiiicatioll ofAir Filters Method of Test for Water Rejection PerfOnTlatce of Louvrcs Subjected 1(1
Simulated Rainfall Test Procedure for Acoustic Loo cs Specification 10 Floor GrilJes - Types Performan e and Method ofTest Specification for the Determination of the Collection Efficiency of SilJ1d
Trap Louvre Domestic Mechwlical Vclltllalion Systems with Heal Recovery Fan Application Guid
~an and Ouctwork Installation Guide Guide to Fan Noise and Vibration
pecification of Requirements for JallJral Smoke and Heal Exhausl Ventilators
pecification for Powered Smoke and Heat Exhaust Ventilators
Specification of Requirements for Smoke Curtains Design Gujue of Smoke Ventilation for Single Storey Lodustrilll Building~
Including those with Mezzanine Floor and IIi Racked Storage Warehou es - Issue 3
Guidance for the Design of Smoke entilation YSlem for Covered and Undergrollnd Car Parks - lssue 1
Application of SOloke Control Equipment and Syst m Guid to Good Practice - Isue J
58
DW154 Sp(C~tiifitiol for Plastics Ductwork
BRITISH STANDARDS INSTIT TION Sales Department 101 P ntooviLle Road London NI 9ND (felephone 020-78 1 78801)
CP 413 1973 Ducts for building ervices
SS 476 Fire tes on building matenals and lruc(ure
Part 4 19 4 Non-combustibility lest or materials
Part 6 I Fire propagation lest for materials
Part 7 1993 Surface spread of tlarnJ tesls for materia
Part 20 1987 Fir resistance of elements of construction
Part 21 1987 Fire r sistlUlce of loadbeanng elements of construction
Part 22 1987 Fhe istallceofllon-loadbearing elemcllts ofconsttuclion Part 23 1987 Contribution of componcnts to the fire resistance 0 a
structure
Part 24t987 Fire resi lance of wl1lilation ductl
SS 5588 nan 919 0 Fire Precautions III thc desIgn and OOSlnJ lion of buildings
S 729 1971 Hot dip galvanized oatiugs (or irOIl aod stcel articles
BS 1449 Steel plate sheet and Irip
Pan 11991 Carbon steel plate heel and strip Part 2 1983 Stainless steel plate sheer and strip
and
B middotENJOI49-2 996 BSEN 10149- 1991)
BSEN 10131 1992
BSEN22063 Sprayed metal coarings 1994 Protection of iron and steel by aluminium and zinc against
atmospheric cOlosion Irotectiotl of iron and ste I against corro ion and oxishydation at elevared temperatures
BS 353 1981 Glossary of lerms relnting to thermal insulation
BS ISO 1479 Self-tapplngscrewsandmetallicdri c crew
B -lSO 7049
1994
B 4800 1989 Painl colour for building purposes B 4848 l0 rolled structural steel sections
Part4 1972 Equal and unequal angles BS 5422 1990 Specification for the use of therm illuating matcriulS
SS 5720 1979 ode of practice for mechanical veutilating and air C 11shy
dirionin bull in building
l3S PR 12814-1 Bend resting for plasric welds
SS PR 12814-2 Tensile testing for plastic welds
SS PR 13067 Appro altesting for plastic welds
BS PR EN I 100-] Vi ual in pection ofplaslic welds
SHEET METAL AND AIR CONDITIONING CONTR-CTORS NATIONAL ASSOCIATION INC (SMACNA) Headquarters 420 I Lafayeue Center Drive Chanlilly Virginia 2051-1209
Mailing Address pa Box 221230 Cbantilly Virginilt120 153-1230
Telephone (703) 803-2980 Fax (703) 803-3732
Accepted IJJdustry Pl3Gtice for Industrial Duct Constnlelion 197 ) i-rchitecmral Sheet kwl Manual ([993)
Comractors Guide lor Modification 10 ooslruerion Colllraets 1993 Ducted Eleclric Heat Guide for ir Handling Ssrerns (1994)
En~rgy ollservatioD Guidelines (1984) Energy Recovery Equipment yslClllS (199l
Fibrou GIns Duct onS1ntClion Standards (1992)
Fire Smoke amp Radiation Damper In tall Guide for HVA Syst ms (1992) Guide t leel Stack 1(95)
HVA Air Duct Leakage Test Manual (19 ) HVA COlllmissioning lvlanual (1994)
H A Duct Construction Standards-Metal amp Flexible (1995) Addendum 01 (Nov 1997)
HVA Duct Systems Inspection Guide (1989)
HVA ySlems-Application (1986) nVAC ByternS-DLlct D ign (1990)
HVi Systems-Testing Adjusting amp Balancing (1993)
indoor Air Quality Manual (1993) tcheu quipment Fabrication Guidelmes (1990)
Managers Guide for elding (1993)
Rectangular Industrial Duct Cons1TUction Standards (19 0) Round Industrial Duct oustmction Standards (1977)
Sei mic Restraint Manual (1991) (wl Appendix E 1993) SMACNA Ma le Index ()fTechnical Publications (1995) Tbennoplnstic Duct CPY ) Construction Manual 1994)
DEPARTME OF THE ENVIRO MENT (Publications Centre) H Stationery Oflice 5 Nine Elms Lane London SWS 5DR
MampEJ 011972 Electrical in tallat1011 in buildings ( ew Editiou)
IampE 0319 Healing hot and cold wat r steam and gas losla1lations for buildings
M amp - No4 1970 Central heating and hot and cold ~ ateT in tallations for
dwelling
M amp ENo100 1971 Mechanical ventilation for building~
ASSOCIATION FOR SPECIALIST FIRE PROTECTlO As ociation House 235 Ash Road AJdershot Hampshire GUl2 4DD
Telephone OJ25221322 Fax 0 J252 333901
lublicalioos Fire Ratcd and moke Outlet Ducrwork An Industry Guide t Design and InSlalla lioll
HEALTH AND SAFETY EXEC TIVE Rose Court 2 Southwark Bridge London SEl 9HS Telephone 020-7717 6000
TWJ THE WELD G TlTUTE Abington Hall Abington Cambridge CB16AL Telepbone 0 J223 89162
Publication DatJ Oil w~ldll1g of lhermopla lics
59
DW154 wciiwlioll for Plastics Ductwork
A -=--DIX
Factors
Specific gravity shy pp = 091 approx UPVC = 14 approx
Some miscellaneous conversion factors
To convert
Length Inches to millimetres Feet to metres
Multiply by
2540 03048
To convert
Millimetres to inches Metres to feet
vIultiply by
003937 3281
Area Square inches to square millimetres 6452 Square millimetres to square inches 000155 Square feet to square metres 00929 Square metres to square feet 10764
Volume Cubic feet to cubic metres Cubic feet to litres Gallons (UK) to litres
002832 2831 4546
Cubic metres to cubic feet Litres to cubic feet Litres to gallons (UK)
35315 00353
022
Mass Ounces to grams Pounds to kiJograms Tons to tonnes
2835 04536
1016
Grams to ounces Kilograms to pounds Tonnes to tons
003527 2205
09842
Volume flow Cubic feet per minute to cubic Cubic metres per second to cubic
metres per second 0000472 feet per minute 2119 Cubic feet per mIDute to litres Litres per second to cubic feet
per second 04719 per minute 2119
Motion Feet per minute to metres per second 000508 Metres per second to feet per minute 197
Pressure Inches water gauge to millibars 2491 Inches wateJ- gauge to pascals (Pa) 2491 I Pa = I ewton per square metre = 10-2 millibars
60
Heating and Ventilating Contractors Association Esca House 34 Palace Court London W2 4JG
Tel 020 7313 4900
e-mail contact Itvcaorguk web site wwwhvcaorguk
Fax 020 7727 9268
DW154 Specificatioll for Plastics Ductwork
STANDARD COMPONENT RAWINGS - ECTANGULAR
55
54
51
50
53
52
49
FIG
~MX
RAWlNG
DmiddotMAX
EfjMAX
Minimum throat rndius = 100 mm
Rectangular shy Round Transformatioll
Eccentric Taper 225deg max in either plane Spliller are required for angles greater than 225deg and hould bi eet the angle between any side and duct centreline
DETATLS
Angled Offset
OUset Taper Splitters are required for angle greater than 22 0
and shoold bi eet the angl between any side and dUCI centrelinc
Mitred Offset
Concentrk Taper 2250 max in ither plane SpUtters are required for angle greater than 225deg and should bisect the angle between any side and duel c ntreline
Radiussed Offset
35
DW154 Splcilcuthm for Plastics Ductwork
STANDARD COMPONENT DRAWINGS ~ RECTANGU AR
Branch ducl DimCllsions widlh (W) (A)
urnl mm up lO 200 75
300 100 400 125 600 150
Ocr 600 200
FIG DRAWlNG DETAILS
56 poundplusmni~~ Rectan~lar - Flat Oval Transformation
57 [ Square Branch
58 er Angled Branch
Branch dUCI Dimensions wfdth (W) (A)
[- mm mm59 3shy Shoe Branch Up (0 200 75
--shy AIshy + 300 100
400 125
450 MAX 600 150
Over 600 200
Branch duct DimensIOn
rP X width (W) A)
60 - 1--shy _
~ mm mm
Bell Mouth Branch pto 200 75 300 100 t 400 125
600 150 Over 600 200
0=0 61 -
~ Bell Mouth
- shy T 4-5deg M x
--I 1-shy
TJ
62 X I ] I
Tele-scopic Joint I Illustrated with flangeL
X63
SBD Single Bladed Damper
36
---
DW154 Spedicatioll for Plastics Ductwork
STANDARD OMPONENT DRAWINGS - RECTANGULAR
DRAWING DETAILSFIG
64 on-Return DamperNRD shyshy
shyXbull
Multi-Leaf Damper Can be piggoted or flanged oppo cd or parallel blade
Alternative controls areshy
q p [gtshy
J HD65 Hand
~MD otori ed
PO Pneumalic
L-lt
l 13G 66 Blast Gate DamperX X
FireSmoke DampersSleeves
211r Ratinggtshy----
L_-
---
----
r----
Ir-- shy
IL- _-l
2hr
With i tallation frame
67 41 r Rating
4hr
Smoke damper SD
Intumc cent Sleeve L-d
37
DW154 Specijicutiolt for Plastics Ductwork
FIG
68
69
70
71
STANDARD COMPONET DRAWINGS shy REC ANGULAR
DRAVING DETAILS
gtshy Access Openings
AP 6 Access Panel - Rerno able
w [ ~ Access Door - Hinged
I ~le Inspection Cover
le -I reg -lt
~X X Flexible Connection
~ Drop Cheeked Radiussed Twin Bend
U Drop Cheek Bend
I
72 Air Flow SymbolX
38
DW154 Specifim[ioll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - ECTANGULAR
FIG DRAWING DETAILS
73
74
75
76
77
Q
Q
rp---t
~
V- I Ir---I
JL --11
THE ABOVE DETAILS TYPICAL PLENUM
Air Terminal Plenums
Plenum with side connection
Plenum with top connection
Cover plate with connection
Special plenum with connection
elescopic conn ction in direction of air flow
39
DW154 SpecijicotiOll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG
78
79
80
81
DRAWING
-23~---pound3-(MALE) (FEMAJE)
-t=j--_j(--d-shy
--L
~ THROAT RADI S= D AS T NDARD
e ~
THROAT Rjf)lU = D A MU)
DETAILS
Straight Duct With male and female connectors
Straight Duct With flange joint and slip joint
Bend MouldedIFormed Applies to any angle ego 30deg45deg60deg90deg Medium radius bend as illustrated Long radius similar but throat radius 0
Segmented Bend 90deg four section minjmum as illustrated
Other Angles 60deg = 3 sections 45deg = 3 sections 30deg = 2 sections
I
i
40 shy
DW154 Speciicafinll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG DRAWING DETAlLS
82 Segmented Twin Bend Radius = D2 max
May also be fabricated from tube
83 Equal Tee MouldedIFormed
84 -~ 1in Bend MouldedIFormed
85 Taper Concentric 1 0 as iUu trated Eccentric 30deg iJJcLuded angle
86 Short Taper
41
DW154 SpcUicatol1 for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG DRAWING DETAILS
87 30 max Offset
Angle Branch
Bran h dUCI Dimcnsions dia (D) lA)
Shoe Branch mm mm 88 Cl
Off rectanguJur Up 10 200 75 lOO 10 400 125
- 00 150 Over 600 200
Bl1IllCh duct DimenlOns din (D) (A
~-$a-Conical Branch mm mm
89 Also acceptable with Up 10 200 r
full conical surface 300 10
400 125
END VrE -shy 600 150 Over 600 200
90
m 75
100 12 150 200
mm Up to 200
_ 300 400
600 Over 600
iUtred Branch
Shoe Branch
J-L----U ~ Bell oulh Branch
ENDV1EW
93
92
91
42
DW154 Specificatiol for Plastics Ductwork
STANDARD OMPONENT DRAWINGS - CIRCULAR
FIG
94
DRAW G
I
~ 30deg 090deg
Breeches Piece
DETAILS
95 amp-----~ Blank End
~-----p Multi-Leaf Damper Can be piggolcd or fianged opposed or parallel blade
Alternative controls areshyri=-+- L-T~
I
---
LT~
I r- -
-+1
J HO Hand96
bMD Molori cd
PD Pneumatic
tl-shy bull
Single Bladed Damper 97 ~ saD
on-Return Damper Vertical application only 98 m~D
43
DW154 Sf1tcificatioll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG
99
100
101
102
DRAWING
$ I-
2hr
1 4hr
SD
~v I I
CO TINENTAL COWL
DETAILS
Iris Damper
Fi reS moke Dam persSleeves
2hr Ratillg
With installation frame
4br Rating
Smoke damper
Intumescent Sleeve
Access Openings
Access panel - removable
Access door shy hinged
fnspection cover
Discharge Continental Cowl
44
DW154 Sp(Cii(ltJll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
DRAWINGltIC DETAns
-
I
I
~
I I I High Velocity Discharge Terminal 103 I
I
I I
J I I 1 ~--
Offset Stack Discbarge Terminal 104 1
~ I e --(-
I
N
I
I
I~
I I Vertical Oischarge with Weather Cowl 105 I
--1--1 I
I
GAPI I
RTl AL DISC) lARGE WITH W ATIIER COWL
45
DW154 SpecUicatoll for Plastics Ductwork
STANDARD COMPONE T DRAWINGS - PLA TEQUIPMENTIMISCELLANEOU
FIG DRAWING DETAILS
106 ~~~ Rectangular Attenuator
107 ~- Circular Attenuator
108
~ Beod Attenuator
109 J ~(f) Heating Coil
110 J ftte Cooling Coil
III Jc[ Electric Heating Coil
112 X F
Humidifier
113 [H XX Axial Fan
114 ~fB1famp Noo-standard Ductwork Cross hntchillg (of any separate type) indicates by reference to a key any non DVil54 ductwork system
115 2llIIIIJIIIIIll Flexible Ductwork
46
DW154 SJeCUicll(iol1 for Plastics Ductwork
TABLE 12 - STANDARD ABBREVIAT ONS
ABBREVIATION FLL
AD Acces Door
AFF Axial Flow Fan
AHU Air Handling nit
All Aluminium
AP Acess Panel
AT Attenuator
AV Air enninal Unit
BE 81ank nd
BQ Blast ate Damper
CC Cooling Coil
CF Centrifugal Fan
CTA Cross alk Attenuator
CVU Constant Volume Unit
DP Drain Point
EEC Electric Heating Coil
El Expansion Joint
FAl Fresh Air Inlet
FA From Above
FB From Belo
fBPP Fabric Backed Polypropyl-ne Sheet
Flexle Flexible Connection
lexfD Flexible Du t
C False Ceiling CO an oil Unit
fD Fire Damper
FFL Finished Floor Level
FJ Flanged Joint
FOAM Rigid Polyurethane Self xtinguishing Foam
FOB Flat on Bottom
FOT Flat on Top
GAM Galvanised after ManufacttrJc
GRP Glass Reinforced Plastic
GSS Galvanised Sheet Steel
HC Heating oil
HD and controlled Damper
HH Hand Hole
HL High Level
HVD High Velocity Discharge
IC Inspection Cover
ID lri Damper
IFS Intumescent Fircleevc
47
DW154 Specification for Plastics Ductwork
TABLE 12 - STANDAR ABBREVIATION CONTINUED
ABBREVIATION
IU
L
tv1D
MS
NRD NTS
OBO
OE
PHD
PD
PP
PP
PRD
PVC
RFC
RSC
R
SBO
SO
S1 TST
SSL
TA
TB
TO TJ
TP
TV
TV
OS
UPVC
S
V
VAV
50 RSA
FULL
Induction Unit
Low Level
Motor controlled Damper
Mjld Steel
on Return Damper
at to cale
Opposed Blade Damper
Open End
Parallel Blade Damper
Pneumatic controlled Damper
Polypropylene
Self xtinguishing Polypropylene
Pressure Relief Damper
Polyvinyl Chloride
Rolled Form Chamlel
Rolled Steel Channel
R fUnit
Singl Blade Damper
Smoke Damper
Slip Joint
Stainl t el
tructural Slab Level
To Ab vc
To Blow
Top Down (In Direction of Flow)
Telescopic Joint
Test Point
TU111iog Vane
Top Up (In Direction of Flo )
Voles Otherwise Stated
Unpl3sticisecl Polyvinyl Chloride
Underside
Ultra Violet Light
Variable Air Volume
Rolled Steel Angle (Vith Size)
48
DW154 SJeriiflllioll for Plastics Ductwork
A2 DUCT PRESSUREAPPE DXA Ductwork con truct d to DWIl54 will bebullbullbullbullbullbullbullbullbullbullbullbullbullbull
Air Leakage From Ductwork To be read in conjunction with DW143 A practical guide to Ductwork Leakage Testing
CAUTION As highlighted ill both this docul1lenr and DW14 I lot ellough emphasis can be placed 01 the fact that except for high pressure class C the much more stringent ductwork constructional standard brolght about b the general acceptance of DW154 have irtlally negated the requirement for leakage-testing It is essential lO realise lhat except where it is mandatory this doclllllelll is nOl an endors ~lIlent of the rourine testing of ducts bllt purely a guide to outline the procedures for cononnity with the air leakage limits ill Table l Where the specified methods of assembly and
A3sealing of dlcls are u ed a vi ual inspection wil ordinarily sl~fll e for ver(iatioll of a well engineered and a ceptahfy airtight COl1strucrioll WHERE NOT MANDATORY DUCT LEAKAGE TESTING IS GENERALLY AN UNJUSTIFIED AND SUBSTANTIAL EXPENSE
A1 INTRODUCTION L akage from ducted air distribution systems is an Lmportant consideration in the design and operation of ventilatjon and air conditioning middotystems A ductviork t)ystem tbat ba limited air leakag within defiucd limits wiH cnsUft
that tile design characteristics of the sytem can be maintained It wilJ also ensure that energy and operatLonal cosb are maintained at optimum levels DucLwork constlucted and Ulstalled in accordance with DW154 should minimise a level of air leakage that it) appropriate to tll operating static air pre sur in tile system
A4However it is recouuised that tbe environment in wtJich middotystems are installed is not always conducive to achieving a predictable level of quality in term of system ajr leakage and it is therefore accepted that designer may sometimes require tlle ystem to be tested in part or in total It should be ecogni ed that the testing of duct systems add a ignificant cost to the installation and incur some extra tjm within the programme (Se 47 and 64 re mandatory te-sting)
manufactured to a structural standard that is compatible with the system operating pressure There are three classes of duct con truction to eorre pond with the three pre ure clas meations Class A Lo pressure ducts suita le for a maximum positive operating pressure of 500 Pascal and a maximum negative pressure of -500 Pascals Class B IVledium pressure ductmiddot suitable for a rnaxilnuJJl positive operafjn o pressure of 1000 Pascals and a maxllnum negative pre sure of -750 Pa cal Class C High pre sure ducts suitable for a maximum po ilive operating pressur of 2000 Pa cals and a maximum negativ pres ur of -750 Paltcals
LEAKAGE FROM DUCTWORK Leakao-e front pia tic air ducts occur at the joint~ and is therefore proportional to the total surface area orthe du twork in th system Tb level of leakage i imilarly related to tIle air pres ure in th du t system and whilst there LS n precis formula for calculating the level of air los it i generally accepted that leakage will increase in proportjon to pressure to rbe pOvver of 065 The effect of air leakage from high pressure velocit ductwork is critical tn terms of system perfomlan dege energy consumption and the risk of high frequency noise as ociated with leakage These problems are le critical with medium pressure 10 ity systems but should be con idered Low pres mevelocity ducts present the lowe~t
ri k in tenn of tbe effect of leakage on the operation of the s stern
SYSTEM LEAKAGE LOSS As there i no di ct relatLonship between th volume of air conv yed and the surface area f the ductwork sy tern required to match the building configuratmn it is difficult to express air leakage a a percentage of total air volume Similarly the operating pressure will vary throughollt lh 3 system and a leakage is related to pre me the calculations ar comple However it is generally ac epted tbat in typical good quaJjty systems the leakage from
49
DW154 Specificatioll for Plastics Ductwork
each class of duct llnd r operating condition will be io the region of CIa S A low pressure 6 Clas B medium pres un 3 Clas C high pressure 2
A5 SPECIFYING AIR LEAKAGE TESTING Re peeting both the co -t and programme implications a sociated with te ling du 1 for leakage the designer may for example indicate that a particular system is te ted as follow
a) High pressure ducts - all tested b) Medium pr ssure duets - 10 of the
ductwork shall be s eet d at random and tested
c) Low pre sure - unte ed In any case where a random te t i elected for medium pre sure ductmiddot the followin c1au~e is suggested for inclusion by the de ign r
The designer hall elect at random a maxirnwlI of 10 of the dUCl system to bt tested for air leakage The duct hall be tested af the pressure recommended in Table J3 for the assifi atiol for the ectiol1 of the ductwork that is to be tested The tests shall be carried Ollt as the work proceeds and prior to the application of thermal insulation In the event of test failure of the randomlY selected section the designer shall have The right to select two La1her e tiolls at random for resting Where succes ive failures are identified there shall be a Tight to require rhl COl11raCWr 10 apply remedial attention to the complete ductwork system Th contractor shall provide documented eviden e of the calculalions used to arrive (1
the allowable 10 I for the section to be tested and the client or his agent shall willess and sign the results of the test
able 13 Air leakage rates
Maximum leakage of duct work Static
prcssUft Low-pressure edium-prc-sure I Iigh-prebull me diJfercntial Class A Class B Class C
1 2 J 4 Pa Litres per second per quare metre of surface area 100 054 018 ZOO 084 028 300 110 037 400 132 044 500 153 051 600 058 019 700 064 021 800 069 023 900 075 025
1000 080 027 1100 1200 1300 1400 1500
029 030 032 033 035
1600 1700 1800 1900 2000
036 038 039 040 042
Note Recommend d mean test presures are highlighted iD bold type with the actual selection being left to tll test operator
50
DW154 Sfeeiieaioll for Plastics Ductwork
A9
A10
and air leakage classification for the y em under test
DESIGNERS CALCULATIONS The designer can middotaJculate with reasonable accuracy the predicted total loss from a ystem by
a) Calculating the operatin presure in each ection of the sy tern
b) Calculating the surface area of the ductwork in each correspondin pre lire s ction
c) Calulating the allowabl~ los at the operating pressure for each ection of the system (see table 13 for allowable leakage figures)
VARIABLE PRESSUR S IN SYSTEMS De igner can achieve significant co t saving by matchina operating pressures throughout the system to constmctional standard and appropriate air leakage testing eO the practice of specifying construction tandards for whole duct sy tems based on fan discharge pre sure may incur unnece sary costs on a project For example ome large sy terns ould well be classiC ed for I akage limits as follows
Plant room risers CJas C Main floor distriblltJou CIa B Low pre sure outlets Cla A
A6 SPECIAL CASES There may be ~itLlations on a project where circumstance dictate thal pecial consideration be given to containing air loss s eg a long mn of duclwork may incur a di -proportjonate level of air 10 s In ca es such as thi example the designer can specify an improved tandard of airtighmess ie 80 of alJo~able 10 s for la B Ju ts The designer sbould not specif a CIa C t sI at CIa s C pressure for a CIa s B ducl
A7 SUGG S ED RANGE OF TES ING
A8 TESTING OF PLANT ITEMS Items of inline pJant (eg Fig 106 to 115) will not normaUy be included in an air I akage test The dllctwork contractor may indud such itelllS in tbe te t jf rh quipm ot has a certificate of COnfOlnlity for Ihe pres ure clas
bull High pressure duct bull Medium pre sure ducts bull Low pre sur ducts bull Exposed extract syst ID bull Ceiling void extract
systems bull Secondary ducts from
VAV or fan coil units bull Flexjble duct bull Final connections and
branches to grille and diffusers
100 test See A5 Untested UDt sted
Untested
Untested Untested
Untested
SI
i
DW154 SJecijicafion for Plastics Ductwork
ig 116 Permitted leakage at various pressures
Leakage in litres per second per square metre duct surface area
Vgt
o ltgt 0 ltgt N
ltgt Cgt
0 0 cc
0 0
~
g =
g ~
c 0
J
ltgt 0 I
~ ] tn
ltgt ltgt
In ol
~ 0 ~ 8 ~
~
c ltgt ltgt
~ CJ
~ ~ ~ ~ 8
0shyij
~ ~ ~ t
ltgt ltgt 00
l
~
~ Q
c C
~ rshy
e ltgt
I 1
I Cgt ltgtv
c Co ~
~~ ~ 10
I
0 Cgt
fJshyq 410 ) 1 ltgt
ltgt N
~ shy ltgt ltgt
~ I 1
c
52
DW154 Specificatio for Plastics Ductwork
Example of a completed test sheet Test No
General
Name of job N~ jC43Pt(r2lef Building Repound ~(~~0
Part 1 - Physical details
a Section of duct work to be tested ~(diffPIfff~el1f3rd Floor
b Drawing Number g91~~ c ssure aSSJ L atlOn V~Jl~IRfYgtg~~lPre Cl T Class C
d Test static pressure -(9 raErq~ ~~~~-~~J~~~ ~~ ~~~~ll
Leakaoe factor 9~-tre3$ecMz I OM REFTOTABLE 13)e b bullbullbullbullbullbullbull
f Surface area of duct under test Q~tJJItetre$ CPROMCALCU TIO BELOW)bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull ampampamp bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull
g ]Vlaxi mum permitted leakage -~ (~i~~0 ~~r~~ ~~~l-~-11~ ~~~Q
Part 2 - Test particulars
a Duct static pressure reading 9QFt~q~ ~ middot~~~1 ~~
b Manufacturer and type of liow measuring d vice (-~~~cJ~Y-9Q7EYg c Range of measurement of now measuring device QtP)OQ~(e~~~0I~~~~1~I~ ~~~~~~W~
d Reading of flm measurin o device pmiddot IFROM RIO)ftscag ~
I (DERlVED [ROM CHART SUPPUED WITH RIG US 0 ud)1e Interpreted air flow leakage rate ~(~~~f~~~ (~l~~~~~~~~~~~~~~~~~I
f Duration ~~~~~norn~allY l~ lnil1Ut~~d~~~ it1~ W~ Date of test ~(lITled ut by Wltll s ed by ~ ~
(~lJ MIJLrr) (Si~rrfltJUYJ
Printed Name 1~g0f~ Printed Name ~~Y~9~ and Company 7jl~~~~~( UJd CompanY AB COII$Itallt8
Width and depth or diameter
Periphery ength Area
millimetreS millimetres metre qL1are metre
800 x 750 3100 1755 5440
600 x 650 2500 557 1193
300 x 300 1200 120 144
305 din 958 700 670
250 dia 785 450 353
TOTAL 8000
53
DW154 Specijilarion for Plastics Ductwork
pA XB
Guida ce No es For he ransport Handling and
Storage of uctwork
avoid damage to adjacent duct panels In somc ca es particularly on con acts calling f r repetitive sizes the use of timber jigs and spacers may be justified Where reduced bulk and greater protection are major factor such as consignments for export transporting ductwork in L shape sections may justify the increa ed ite as embly co ts
It is recommended that before a contract is finalised that consideration is given to the subject of site acces material handling and storage as tbcy havgt a strong influence on the cost efficiency of the overall activity of ductwOlk installation
B3 Handling To minilnise th risk of damage duct sections should be clearly identified and deliveries to site should be closely linked to the installation programme so as to avoid accumulation of
B1 Storage and Handling of Ra Material Material should be stored in suitably designed racking out of direct unJight Where possible the e racks should be metal to earth Edges of cut she t may be harp and protective gloves are advised Wearing teel toe-capped boots is recommended Most pIa tic sheet is manufactured with smootb mfaces andor is suppLied with protective coating Care must be taken to prevent accidental lippag of stacked materials Beiuoshy good electrical insulators the movement of stock unless earthed will allow the build up of stati All stock shapes are chemically stable at normal temperature Whil t some raw materials used in their manufacture may themselves pre ent a toxic hazard once incorporated into the lOck bape they no long r constitute such a hazard and no dermatitic bazard are known nor are any
unfiJied ductwork and minimise double handling It is important to recognise that ductwork panels joint and corners arc susceptible to damage and care must be taken wheu band ling such material through a site During handling individual item of duct work may be liable to light cross sectional deformation until thev become an integral pan of a completed ductwork system Whilst this may temporarily detract from its intended appearance thi deformation will not have any detrimental effect on the functionality of the finally a semblecl system Installation of duct work and asociated plant items ill illevitably involve manual handUng The responsibi Iiry of employers and employees to a ses the risk of personal injury during mallual handling operations is et out in the HS E publication L23 Guidance on Manual Handling Regulations 1992
environmental problems expected 84 Site storage
B2 fransport Large capacity vehicles with high-sided open or closed-top bodies are tlle mo t suitable for the transport of dllctwork Careful consideration should be given to the
Adequate floor space IDust be provided within tbe building for the site storage of ductvork Such storage shalt make due allowance for thc stOf(ne of ductwork in stacks such that access ~ egt
between them is of sufficient width to pennil the removal of item without interference to
unloading of transport on sit a not all siJes b n fit from the material handlino- and access facilities that exi [ in a manufacturing workshop such as crane- fork-lifts or loading bay Site handJiog facilities along with
adjoining sta ks Ductvork components should be positioned so a to avoid crushing Ductwork of small panel size may be stored horizontally however care should be exercised to ensure that tack sizes are limited 10 within
ehicular acce s restrictions may itilluence the type and ize of transport to be uWised
engtlls of ductwork should be positioned 0
the tmctural strength of the duct sections to prevent distortion of the lower sections within the stack
as to avoid crushing Lengths Witll projections such as branches and bends i1anges girths damper quadrauL should be loaded so as to
54
DW154 S1tciic(ltioll for Plastics Ductwork
85 Internal cleanliness of new ductwork The site storage of ductwork introduces the important cODsideration of maintaining the internal cleanliness of the ductwork R feren e should be made to HVCA documentshybull DWffM2 Guide to Good Practice - internal
Cleanliness of New Ductwork Installations If the above conditioDs can not be satisfied consideration should be given by tJle designer to amending the specification to include for Po t Installation Cleaning as covered by tJ1C HVCA documentshybull TRJ17 Guide to Good Practic - Cleanliness
of Ventilation Systems
APPE DIXC
Fi e Retardant inishes C1 Improvement in the fire retardancy of plastic
ducts can be achieved to varying degrees and is wholly dependent llPOll the surface coating laminating resin selected and construction specification adopted In some instances smoke emission is coILSidered equaUy with other speci fication requirernen ts of the materials resistance to ignition and bumjng It is therefore important for design rs to establ ish the clients and officers detailed requirements and not rely on a tbird party interpretation of fire resisting or fire retardant Where possible the specification should refer dir etly to compliance with a British or European Standard identifying the specific sections applicable There are various types of resin and mat rcLnforcements that can achieve a Class 1 surface spread of flame ratin o when tested according to BS476 Part 7 (1987) This test puts materials illto Class I - 4 in descending order of perfoDllance according to the rat and extent of flame spread over their surfac under standard beating conditions Materials should also be tested for flre propagarion to BS476 Part 6 (1989) Tbi tesr measures the amount and rate of heat evolved by the material when subjected to standard heating
conditions Test results are given as an index of Perfonnance (i) whicb is based on three sub indices (iJ (i1) (h) The higher the value of the Index of Performance (i) the greater is the material s contribution to fire growth The higher the value of the sub-index 0) rhe greater the ease of ignition aod flame spread The highest product performance classification as defined in Approved Document B of the Building Regulations is Class O This is acLlieved if a material surface of a composite ploduct i~ either a) composed throughout of materials of
limited combustibility or b) a Class I material which has a tlre
propagation index (i) of not more than 12 and sub-index (i l ) of nor more than 6
01 J Class 0 is not a cla$sif1cation identified in any British Standard test
There are resin system reported to be classified to Class O when tested to BS476 Pcl1S 6 and 7 however designers need to ensure that such sysrems can be applied to their proposed design In propriety resinmat system available the fabrication techniques and COITect application are critical to the integrity of the reinforcing and clas ificatiol1 For example in some systems the u e of a non-fire retardant gelcont on a fire retardant substrate would reduce the classification For further information see HVCA publication DW144 Appendix D
55
DW154 SplCijiClIliol1 for Plastics Ductwork
x Guidance otes For nspectmiddoton Servicing a d
Clean-ng Access Openings
D1 GE ERAL This appendix highlight in ummary fOI111
the acce considerations that hould be made by the design r iD terms of inspection servicing and cleaning Having considered the seop and the design of the dUCI work system relative to the guidelines outlined below the designer should clearly indicate which levels of acces should be incorporated into the manufacture of a new duct work system (See Table 14 and Note I b low it
D2 DESIGN CONSIDERATIONS
D21 In ptction and servicing requireshyments are set out in Section 15 of Lhis specification
D22 Cleaning requirements are set out in the HVCA pubUcation TRl7 Guide to Good Practice Clean Lines of Ventilation Systems and the guide tates The precise location ize and
type of access would be dependent on the type of ductwork cleaning inspection and te ting metbods to b adopted Care protection and standards of cleanliness prior LO cOlllmisionin o
are set out in th AV A publication DWITM2 Guide to Good Practice Internal Cleanliness of New Ductwork Installations and th guide state Wh re specific limits of cleanliness are required ductwork sball be cleaned after installation by a spcialist cleaning contractor It will b in the interests of tht desioner botb financially and practically to cunsider employing a specialist c1eauing contractor at tbe
outset of a contract to internally clean newly installed ductwork prior to bandover This approach would reali e the following benefit shyi) Tb actual numb r of cleaning
access panels could be detennined to suit the method of cleaning to be adopted (This may be 1 s than the maximum requiremen listed under Lev 13 of Table 14)
ii) Clear directions could b given to the ductwork contractor as to tJle size and location of cleaning access panels that are required to be fitted during the mauushyfaclunng pro s
iii) The specialist cleaning operation prior to commi ioning vould enable the cleaning contractor to verify the practical acee requirement for the future cleaning operation associated -vitb a regular maintenance programme
iv) A specialist cleaning operation prior to commissioning would allow the designer to omit from the speeilicatiolJ the DWrrM2 requirem nt for factory sealing protection wipe downs and capping-off
v) Specialist Ieall ill 0 to the measurable standard defin d in TR17 will allow an objective definition of cleanline to be achieved
Car ful consideration must be gIven by the designer to the practl aJ problems associated witb the manufacture and fitting of suitably si Led access panel on small cross section duct and on the circular faces of rouod and flat oval ducts in particular
D23 Special con ideration must be given by the de igner to the practical problems associated with gaining personnel access to heavily congested ceiling areas and multi-la red du twork systems This approach would avoid
56
DW154 Spfciication for Plastics Ductwork
the possibility of access panels being D3 ACCESS 0 IN-LINE EQUIPMENT incorporated into a ductwork system at the This appendix unly covers acc il1spection manufacturing stage that were later found in through the ductwork body adjacent to an item practice to be inaccessible for either ervicing of in-line equipment and not openings in the or cleaning activities equipment itself
able 14 Acce requirements for inspection servicing and cleaning
HVCA PUBLICATIO REFE NeE (uidtgt 10 Gund Prartict
Adjace t OW144 Cleanliness orVcnlillltio S~lcr~ fRjJ7
in-line LeyeJ 1 Level 2 Level 3 ite sequipment pcdionSen lcin~ Section d C1eaniJl( SUn(O)lnspc lion Palle ltk~m_n
2011 (minimum OiL Jubje-ct to duct ~zel (ft~ -Panels
Control Da pcrs One (inspection) 203 One 300 mm x 200 mm Both sid Fire Dampers One (sCTjdJl~) 20211 One 300 0101 x 200 mm One side HeatingCooling Coils One (inspedion) 20213 One 300 mm x 200 mm (lIpstream) Both sides Attenuators (rectangular) None required One 300 mm x 200 mm (downstream) Both sides Attenuators (circular) one retluired One 300 mm x 200 mm (downstream) One side Filter Sections One (inspection) 20212 one required Uoth sides Air Turn Vanes None requjred None required Both sides Changes of Direction None required one required One side In-Duct FansDevices One (inspection) 20213 None required Both sides l
1 In the absence of any indication by the designer only Level ) access will be jncorporated into a new ductwork system
2 Tbe panel izes associated with Lev lis I and 3 acee s ar e middottablished by reference to Section 20 of DW144 and Section 2 ofTRll7 respectively
57
DW154 Speclfifatio for Plastics Ductwork
pA XE
B-bliography Included in this Bibliography are technical pUblications which may be of interest (0 ductwork designers fabricators and erectors and to tho e in the heating ventilatlng air conditioning industries generally nquiric should be made of the relevant organisation at the address quoted Since its publication other addresse contained within 0V154 mav have changed and some pubJicalions may have been superseded
HEATING AND VENTILATING CONTRACTORS ASSOCIATION
4 Palace Court London W2 4JG Telephone 020-7229 2488 Fax 020-7727 9268
Orders fo FlY A Publications Old Matlsion House Eamont Bridge Penrith Cumbria CA 10 2BX (Telephone 01768 864771 Fax 01768 86718) Email hvcapoblicationshvwelfarecouk DWn 44 pe ilicatiun for sheet mctal duclwork (Iow- mediulllshy
and high-pressure) 1998) DWIl4 A practical guide to dUGI ork I akage te ting
(revised 2000) DWII54 Specification for plastic~ duct rk DW171 Guide to good Practice for kitchen venlibtion system DW191 Guide to good pracuce glass fibre ductwoJk DwrrMI Acceptance cheme for new products - Redangolar cro
joint classification Guide to good pra tice - Internal cleanliness of new ductwork installations Guide to good practice for the design for the Installation of lire and smoke uampers
J 1Other puhlications
HampV safely guide 5th edition JS2 Tool box talks JS5 Weldlng Safety booklet JSI9 afety facts bo klet Fact sheets 1-24 2nd edition JS2J COSHH manual volume 1 Advice on compliance with the
regulations 1521A CO I-rH manual volume 2 Asses mcnt h ets JS23 Ri k management manual TR3 BrazinltT and bronze welding of copper pipework cUld sheet
(I 976) TR5 Welding of carbon steel pipework (1980)
TR6 Guide to Good Practice for Site Pre sure Testing of Pipework (19 0) Guide to good practice cleanliness of ventilation Ylem
CHARTERED IN TITUTlO OF BUILDING SERVICES E G EERS Delta House 222 Balham High Road London SW12 9BS rTelephone 020-8675 5211 Fax 020-8675 5449) CIBSE Guide Volume A Design Data Volume B In tallatiol1 and quipment Data Volume C Reference Data
CommlssioniJIg Codes These Codes eover the preliminary checkS eUing to work and regulation of vanous catcgories 0 plan The Codes give a guide to design implications Series A Air Distnbution Systems Series B Boiler Plant
ri s C Automatic Conlrol ystems Cr1es R Refrigerating Sy terns
Sene iN Water Distribution Systems
Technkal Memonllda TM 4 Design Notes for the Middle East TM bull Design otes for Ductwork TM 13 Minimi iog lhc Risk of egiounaires Disease
Research Reports RROI95 Ventilation system hygiene - A review of published
infomlatioo on lhe occurrence and ffects of Olltamination Rl~02J95 Air-to-air heal rec v ry RR0395 rnfluen e of HV C on smoke detectors
ATlONAL ENI [ERING SPECIFICATION LfMITED Southgatc hamber 3739 Southgate Street Winchester S023 9EH (Telephone 01962 842058 Fax 01962 R(8982) BUfLDING S RVICES RESEARCH AND [ ORMATION ASSOCIATIO Old Bracknell Lane West Bracknell Berkshire RG 12 4AH (Telephone Brackl1eU (01344) 426511 Fax 01344 487 -7 )
Application Guides AGln4 De tglJing Vana~le Volume middotylans for KOOnl
iir Movement AG1I91 Commissioning of V Sylcms in Buildings 11 6194 Fire Dampers
B) 94 cntiJalion or KitcneTls
AG389 The Commls ionin of Air Systems In Buildmgs AH2192 Commissioning of Bern - A ~ode of Practice TN2417 I Fire Dampec il) Ventilating Ducl
BEATING VENTILATING A AIR CONDITION G MA UFACTURERS ASSOCIATIO (HEVAC) HEVAC Henley Road Medmenham Marlow Buck SU 2ER (Telephone 01491 578674 ox 01491 575024 Emoimiddot infofetacouk)
Publicatjons Air Diffusion Guide Guide to Air Handling Unit Leakage Testing Guide to Good Practice Air Handling Unit Real Room Acoustic ~ st Procedure Specification for the ertiiicatioll ofAir Filters Method of Test for Water Rejection PerfOnTlatce of Louvrcs Subjected 1(1
Simulated Rainfall Test Procedure for Acoustic Loo cs Specification 10 Floor GrilJes - Types Performan e and Method ofTest Specification for the Determination of the Collection Efficiency of SilJ1d
Trap Louvre Domestic Mechwlical Vclltllalion Systems with Heal Recovery Fan Application Guid
~an and Ouctwork Installation Guide Guide to Fan Noise and Vibration
pecification of Requirements for JallJral Smoke and Heal Exhausl Ventilators
pecification for Powered Smoke and Heat Exhaust Ventilators
Specification of Requirements for Smoke Curtains Design Gujue of Smoke Ventilation for Single Storey Lodustrilll Building~
Including those with Mezzanine Floor and IIi Racked Storage Warehou es - Issue 3
Guidance for the Design of Smoke entilation YSlem for Covered and Undergrollnd Car Parks - lssue 1
Application of SOloke Control Equipment and Syst m Guid to Good Practice - Isue J
58
DW154 Sp(C~tiifitiol for Plastics Ductwork
BRITISH STANDARDS INSTIT TION Sales Department 101 P ntooviLle Road London NI 9ND (felephone 020-78 1 78801)
CP 413 1973 Ducts for building ervices
SS 476 Fire tes on building matenals and lruc(ure
Part 4 19 4 Non-combustibility lest or materials
Part 6 I Fire propagation lest for materials
Part 7 1993 Surface spread of tlarnJ tesls for materia
Part 20 1987 Fir resistance of elements of construction
Part 21 1987 Fire r sistlUlce of loadbeanng elements of construction
Part 22 1987 Fhe istallceofllon-loadbearing elemcllts ofconsttuclion Part 23 1987 Contribution of componcnts to the fire resistance 0 a
structure
Part 24t987 Fire resi lance of wl1lilation ductl
SS 5588 nan 919 0 Fire Precautions III thc desIgn and OOSlnJ lion of buildings
S 729 1971 Hot dip galvanized oatiugs (or irOIl aod stcel articles
BS 1449 Steel plate sheet and Irip
Pan 11991 Carbon steel plate heel and strip Part 2 1983 Stainless steel plate sheer and strip
and
B middotENJOI49-2 996 BSEN 10149- 1991)
BSEN 10131 1992
BSEN22063 Sprayed metal coarings 1994 Protection of iron and steel by aluminium and zinc against
atmospheric cOlosion Irotectiotl of iron and ste I against corro ion and oxishydation at elevared temperatures
BS 353 1981 Glossary of lerms relnting to thermal insulation
BS ISO 1479 Self-tapplngscrewsandmetallicdri c crew
B -lSO 7049
1994
B 4800 1989 Painl colour for building purposes B 4848 l0 rolled structural steel sections
Part4 1972 Equal and unequal angles BS 5422 1990 Specification for the use of therm illuating matcriulS
SS 5720 1979 ode of practice for mechanical veutilating and air C 11shy
dirionin bull in building
l3S PR 12814-1 Bend resting for plasric welds
SS PR 12814-2 Tensile testing for plastic welds
SS PR 13067 Appro altesting for plastic welds
BS PR EN I 100-] Vi ual in pection ofplaslic welds
SHEET METAL AND AIR CONDITIONING CONTR-CTORS NATIONAL ASSOCIATION INC (SMACNA) Headquarters 420 I Lafayeue Center Drive Chanlilly Virginia 2051-1209
Mailing Address pa Box 221230 Cbantilly Virginilt120 153-1230
Telephone (703) 803-2980 Fax (703) 803-3732
Accepted IJJdustry Pl3Gtice for Industrial Duct Constnlelion 197 ) i-rchitecmral Sheet kwl Manual ([993)
Comractors Guide lor Modification 10 ooslruerion Colllraets 1993 Ducted Eleclric Heat Guide for ir Handling Ssrerns (1994)
En~rgy ollservatioD Guidelines (1984) Energy Recovery Equipment yslClllS (199l
Fibrou GIns Duct onS1ntClion Standards (1992)
Fire Smoke amp Radiation Damper In tall Guide for HVA Syst ms (1992) Guide t leel Stack 1(95)
HVA Air Duct Leakage Test Manual (19 ) HVA COlllmissioning lvlanual (1994)
H A Duct Construction Standards-Metal amp Flexible (1995) Addendum 01 (Nov 1997)
HVA Duct Systems Inspection Guide (1989)
HVA ySlems-Application (1986) nVAC ByternS-DLlct D ign (1990)
HVi Systems-Testing Adjusting amp Balancing (1993)
indoor Air Quality Manual (1993) tcheu quipment Fabrication Guidelmes (1990)
Managers Guide for elding (1993)
Rectangular Industrial Duct Cons1TUction Standards (19 0) Round Industrial Duct oustmction Standards (1977)
Sei mic Restraint Manual (1991) (wl Appendix E 1993) SMACNA Ma le Index ()fTechnical Publications (1995) Tbennoplnstic Duct CPY ) Construction Manual 1994)
DEPARTME OF THE ENVIRO MENT (Publications Centre) H Stationery Oflice 5 Nine Elms Lane London SWS 5DR
MampEJ 011972 Electrical in tallat1011 in buildings ( ew Editiou)
IampE 0319 Healing hot and cold wat r steam and gas losla1lations for buildings
M amp - No4 1970 Central heating and hot and cold ~ ateT in tallations for
dwelling
M amp ENo100 1971 Mechanical ventilation for building~
ASSOCIATION FOR SPECIALIST FIRE PROTECTlO As ociation House 235 Ash Road AJdershot Hampshire GUl2 4DD
Telephone OJ25221322 Fax 0 J252 333901
lublicalioos Fire Ratcd and moke Outlet Ducrwork An Industry Guide t Design and InSlalla lioll
HEALTH AND SAFETY EXEC TIVE Rose Court 2 Southwark Bridge London SEl 9HS Telephone 020-7717 6000
TWJ THE WELD G TlTUTE Abington Hall Abington Cambridge CB16AL Telepbone 0 J223 89162
Publication DatJ Oil w~ldll1g of lhermopla lics
59
DW154 wciiwlioll for Plastics Ductwork
A -=--DIX
Factors
Specific gravity shy pp = 091 approx UPVC = 14 approx
Some miscellaneous conversion factors
To convert
Length Inches to millimetres Feet to metres
Multiply by
2540 03048
To convert
Millimetres to inches Metres to feet
vIultiply by
003937 3281
Area Square inches to square millimetres 6452 Square millimetres to square inches 000155 Square feet to square metres 00929 Square metres to square feet 10764
Volume Cubic feet to cubic metres Cubic feet to litres Gallons (UK) to litres
002832 2831 4546
Cubic metres to cubic feet Litres to cubic feet Litres to gallons (UK)
35315 00353
022
Mass Ounces to grams Pounds to kiJograms Tons to tonnes
2835 04536
1016
Grams to ounces Kilograms to pounds Tonnes to tons
003527 2205
09842
Volume flow Cubic feet per minute to cubic Cubic metres per second to cubic
metres per second 0000472 feet per minute 2119 Cubic feet per mIDute to litres Litres per second to cubic feet
per second 04719 per minute 2119
Motion Feet per minute to metres per second 000508 Metres per second to feet per minute 197
Pressure Inches water gauge to millibars 2491 Inches wateJ- gauge to pascals (Pa) 2491 I Pa = I ewton per square metre = 10-2 millibars
60
Heating and Ventilating Contractors Association Esca House 34 Palace Court London W2 4JG
Tel 020 7313 4900
e-mail contact Itvcaorguk web site wwwhvcaorguk
Fax 020 7727 9268
DW154 Splcilcuthm for Plastics Ductwork
STANDARD COMPONENT DRAWINGS ~ RECTANGU AR
Branch ducl DimCllsions widlh (W) (A)
urnl mm up lO 200 75
300 100 400 125 600 150
Ocr 600 200
FIG DRAWlNG DETAILS
56 poundplusmni~~ Rectan~lar - Flat Oval Transformation
57 [ Square Branch
58 er Angled Branch
Branch dUCI Dimensions wfdth (W) (A)
[- mm mm59 3shy Shoe Branch Up (0 200 75
--shy AIshy + 300 100
400 125
450 MAX 600 150
Over 600 200
Branch duct DimensIOn
rP X width (W) A)
60 - 1--shy _
~ mm mm
Bell Mouth Branch pto 200 75 300 100 t 400 125
600 150 Over 600 200
0=0 61 -
~ Bell Mouth
- shy T 4-5deg M x
--I 1-shy
TJ
62 X I ] I
Tele-scopic Joint I Illustrated with flangeL
X63
SBD Single Bladed Damper
36
---
DW154 Spedicatioll for Plastics Ductwork
STANDARD OMPONENT DRAWINGS - RECTANGULAR
DRAWING DETAILSFIG
64 on-Return DamperNRD shyshy
shyXbull
Multi-Leaf Damper Can be piggoted or flanged oppo cd or parallel blade
Alternative controls areshy
q p [gtshy
J HD65 Hand
~MD otori ed
PO Pneumalic
L-lt
l 13G 66 Blast Gate DamperX X
FireSmoke DampersSleeves
211r Ratinggtshy----
L_-
---
----
r----
Ir-- shy
IL- _-l
2hr
With i tallation frame
67 41 r Rating
4hr
Smoke damper SD
Intumc cent Sleeve L-d
37
DW154 Specijicutiolt for Plastics Ductwork
FIG
68
69
70
71
STANDARD COMPONET DRAWINGS shy REC ANGULAR
DRAVING DETAILS
gtshy Access Openings
AP 6 Access Panel - Rerno able
w [ ~ Access Door - Hinged
I ~le Inspection Cover
le -I reg -lt
~X X Flexible Connection
~ Drop Cheeked Radiussed Twin Bend
U Drop Cheek Bend
I
72 Air Flow SymbolX
38
DW154 Specifim[ioll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - ECTANGULAR
FIG DRAWING DETAILS
73
74
75
76
77
Q
Q
rp---t
~
V- I Ir---I
JL --11
THE ABOVE DETAILS TYPICAL PLENUM
Air Terminal Plenums
Plenum with side connection
Plenum with top connection
Cover plate with connection
Special plenum with connection
elescopic conn ction in direction of air flow
39
DW154 SpecijicotiOll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG
78
79
80
81
DRAWING
-23~---pound3-(MALE) (FEMAJE)
-t=j--_j(--d-shy
--L
~ THROAT RADI S= D AS T NDARD
e ~
THROAT Rjf)lU = D A MU)
DETAILS
Straight Duct With male and female connectors
Straight Duct With flange joint and slip joint
Bend MouldedIFormed Applies to any angle ego 30deg45deg60deg90deg Medium radius bend as illustrated Long radius similar but throat radius 0
Segmented Bend 90deg four section minjmum as illustrated
Other Angles 60deg = 3 sections 45deg = 3 sections 30deg = 2 sections
I
i
40 shy
DW154 Speciicafinll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG DRAWING DETAlLS
82 Segmented Twin Bend Radius = D2 max
May also be fabricated from tube
83 Equal Tee MouldedIFormed
84 -~ 1in Bend MouldedIFormed
85 Taper Concentric 1 0 as iUu trated Eccentric 30deg iJJcLuded angle
86 Short Taper
41
DW154 SpcUicatol1 for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG DRAWING DETAILS
87 30 max Offset
Angle Branch
Bran h dUCI Dimcnsions dia (D) lA)
Shoe Branch mm mm 88 Cl
Off rectanguJur Up 10 200 75 lOO 10 400 125
- 00 150 Over 600 200
Bl1IllCh duct DimenlOns din (D) (A
~-$a-Conical Branch mm mm
89 Also acceptable with Up 10 200 r
full conical surface 300 10
400 125
END VrE -shy 600 150 Over 600 200
90
m 75
100 12 150 200
mm Up to 200
_ 300 400
600 Over 600
iUtred Branch
Shoe Branch
J-L----U ~ Bell oulh Branch
ENDV1EW
93
92
91
42
DW154 Specificatiol for Plastics Ductwork
STANDARD OMPONENT DRAWINGS - CIRCULAR
FIG
94
DRAW G
I
~ 30deg 090deg
Breeches Piece
DETAILS
95 amp-----~ Blank End
~-----p Multi-Leaf Damper Can be piggolcd or fianged opposed or parallel blade
Alternative controls areshyri=-+- L-T~
I
---
LT~
I r- -
-+1
J HO Hand96
bMD Molori cd
PD Pneumatic
tl-shy bull
Single Bladed Damper 97 ~ saD
on-Return Damper Vertical application only 98 m~D
43
DW154 Sf1tcificatioll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG
99
100
101
102
DRAWING
$ I-
2hr
1 4hr
SD
~v I I
CO TINENTAL COWL
DETAILS
Iris Damper
Fi reS moke Dam persSleeves
2hr Ratillg
With installation frame
4br Rating
Smoke damper
Intumescent Sleeve
Access Openings
Access panel - removable
Access door shy hinged
fnspection cover
Discharge Continental Cowl
44
DW154 Sp(Cii(ltJll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
DRAWINGltIC DETAns
-
I
I
~
I I I High Velocity Discharge Terminal 103 I
I
I I
J I I 1 ~--
Offset Stack Discbarge Terminal 104 1
~ I e --(-
I
N
I
I
I~
I I Vertical Oischarge with Weather Cowl 105 I
--1--1 I
I
GAPI I
RTl AL DISC) lARGE WITH W ATIIER COWL
45
DW154 SpecUicatoll for Plastics Ductwork
STANDARD COMPONE T DRAWINGS - PLA TEQUIPMENTIMISCELLANEOU
FIG DRAWING DETAILS
106 ~~~ Rectangular Attenuator
107 ~- Circular Attenuator
108
~ Beod Attenuator
109 J ~(f) Heating Coil
110 J ftte Cooling Coil
III Jc[ Electric Heating Coil
112 X F
Humidifier
113 [H XX Axial Fan
114 ~fB1famp Noo-standard Ductwork Cross hntchillg (of any separate type) indicates by reference to a key any non DVil54 ductwork system
115 2llIIIIJIIIIIll Flexible Ductwork
46
DW154 SJeCUicll(iol1 for Plastics Ductwork
TABLE 12 - STANDARD ABBREVIAT ONS
ABBREVIATION FLL
AD Acces Door
AFF Axial Flow Fan
AHU Air Handling nit
All Aluminium
AP Acess Panel
AT Attenuator
AV Air enninal Unit
BE 81ank nd
BQ Blast ate Damper
CC Cooling Coil
CF Centrifugal Fan
CTA Cross alk Attenuator
CVU Constant Volume Unit
DP Drain Point
EEC Electric Heating Coil
El Expansion Joint
FAl Fresh Air Inlet
FA From Above
FB From Belo
fBPP Fabric Backed Polypropyl-ne Sheet
Flexle Flexible Connection
lexfD Flexible Du t
C False Ceiling CO an oil Unit
fD Fire Damper
FFL Finished Floor Level
FJ Flanged Joint
FOAM Rigid Polyurethane Self xtinguishing Foam
FOB Flat on Bottom
FOT Flat on Top
GAM Galvanised after ManufacttrJc
GRP Glass Reinforced Plastic
GSS Galvanised Sheet Steel
HC Heating oil
HD and controlled Damper
HH Hand Hole
HL High Level
HVD High Velocity Discharge
IC Inspection Cover
ID lri Damper
IFS Intumescent Fircleevc
47
DW154 Specification for Plastics Ductwork
TABLE 12 - STANDAR ABBREVIATION CONTINUED
ABBREVIATION
IU
L
tv1D
MS
NRD NTS
OBO
OE
PHD
PD
PP
PP
PRD
PVC
RFC
RSC
R
SBO
SO
S1 TST
SSL
TA
TB
TO TJ
TP
TV
TV
OS
UPVC
S
V
VAV
50 RSA
FULL
Induction Unit
Low Level
Motor controlled Damper
Mjld Steel
on Return Damper
at to cale
Opposed Blade Damper
Open End
Parallel Blade Damper
Pneumatic controlled Damper
Polypropylene
Self xtinguishing Polypropylene
Pressure Relief Damper
Polyvinyl Chloride
Rolled Form Chamlel
Rolled Steel Channel
R fUnit
Singl Blade Damper
Smoke Damper
Slip Joint
Stainl t el
tructural Slab Level
To Ab vc
To Blow
Top Down (In Direction of Flow)
Telescopic Joint
Test Point
TU111iog Vane
Top Up (In Direction of Flo )
Voles Otherwise Stated
Unpl3sticisecl Polyvinyl Chloride
Underside
Ultra Violet Light
Variable Air Volume
Rolled Steel Angle (Vith Size)
48
DW154 SJeriiflllioll for Plastics Ductwork
A2 DUCT PRESSUREAPPE DXA Ductwork con truct d to DWIl54 will bebullbullbullbullbullbullbullbullbullbullbullbullbullbull
Air Leakage From Ductwork To be read in conjunction with DW143 A practical guide to Ductwork Leakage Testing
CAUTION As highlighted ill both this docul1lenr and DW14 I lot ellough emphasis can be placed 01 the fact that except for high pressure class C the much more stringent ductwork constructional standard brolght about b the general acceptance of DW154 have irtlally negated the requirement for leakage-testing It is essential lO realise lhat except where it is mandatory this doclllllelll is nOl an endors ~lIlent of the rourine testing of ducts bllt purely a guide to outline the procedures for cononnity with the air leakage limits ill Table l Where the specified methods of assembly and
A3sealing of dlcls are u ed a vi ual inspection wil ordinarily sl~fll e for ver(iatioll of a well engineered and a ceptahfy airtight COl1strucrioll WHERE NOT MANDATORY DUCT LEAKAGE TESTING IS GENERALLY AN UNJUSTIFIED AND SUBSTANTIAL EXPENSE
A1 INTRODUCTION L akage from ducted air distribution systems is an Lmportant consideration in the design and operation of ventilatjon and air conditioning middotystems A ductviork t)ystem tbat ba limited air leakag within defiucd limits wiH cnsUft
that tile design characteristics of the sytem can be maintained It wilJ also ensure that energy and operatLonal cosb are maintained at optimum levels DucLwork constlucted and Ulstalled in accordance with DW154 should minimise a level of air leakage that it) appropriate to tll operating static air pre sur in tile system
A4However it is recouuised that tbe environment in wtJich middotystems are installed is not always conducive to achieving a predictable level of quality in term of system ajr leakage and it is therefore accepted that designer may sometimes require tlle ystem to be tested in part or in total It should be ecogni ed that the testing of duct systems add a ignificant cost to the installation and incur some extra tjm within the programme (Se 47 and 64 re mandatory te-sting)
manufactured to a structural standard that is compatible with the system operating pressure There are three classes of duct con truction to eorre pond with the three pre ure clas meations Class A Lo pressure ducts suita le for a maximum positive operating pressure of 500 Pascal and a maximum negative pressure of -500 Pascals Class B IVledium pressure ductmiddot suitable for a rnaxilnuJJl positive operafjn o pressure of 1000 Pascals and a maxllnum negative pre sure of -750 Pa cal Class C High pre sure ducts suitable for a maximum po ilive operating pressur of 2000 Pa cals and a maximum negativ pres ur of -750 Paltcals
LEAKAGE FROM DUCTWORK Leakao-e front pia tic air ducts occur at the joint~ and is therefore proportional to the total surface area orthe du twork in th system Tb level of leakage i imilarly related to tIle air pres ure in th du t system and whilst there LS n precis formula for calculating the level of air los it i generally accepted that leakage will increase in proportjon to pressure to rbe pOvver of 065 The effect of air leakage from high pressure velocit ductwork is critical tn terms of system perfomlan dege energy consumption and the risk of high frequency noise as ociated with leakage These problems are le critical with medium pressure 10 ity systems but should be con idered Low pres mevelocity ducts present the lowe~t
ri k in tenn of tbe effect of leakage on the operation of the s stern
SYSTEM LEAKAGE LOSS As there i no di ct relatLonship between th volume of air conv yed and the surface area f the ductwork sy tern required to match the building configuratmn it is difficult to express air leakage a a percentage of total air volume Similarly the operating pressure will vary throughollt lh 3 system and a leakage is related to pre me the calculations ar comple However it is generally ac epted tbat in typical good quaJjty systems the leakage from
49
DW154 Specificatioll for Plastics Ductwork
each class of duct llnd r operating condition will be io the region of CIa S A low pressure 6 Clas B medium pres un 3 Clas C high pressure 2
A5 SPECIFYING AIR LEAKAGE TESTING Re peeting both the co -t and programme implications a sociated with te ling du 1 for leakage the designer may for example indicate that a particular system is te ted as follow
a) High pressure ducts - all tested b) Medium pr ssure duets - 10 of the
ductwork shall be s eet d at random and tested
c) Low pre sure - unte ed In any case where a random te t i elected for medium pre sure ductmiddot the followin c1au~e is suggested for inclusion by the de ign r
The designer hall elect at random a maxirnwlI of 10 of the dUCl system to bt tested for air leakage The duct hall be tested af the pressure recommended in Table J3 for the assifi atiol for the ectiol1 of the ductwork that is to be tested The tests shall be carried Ollt as the work proceeds and prior to the application of thermal insulation In the event of test failure of the randomlY selected section the designer shall have The right to select two La1her e tiolls at random for resting Where succes ive failures are identified there shall be a Tight to require rhl COl11raCWr 10 apply remedial attention to the complete ductwork system Th contractor shall provide documented eviden e of the calculalions used to arrive (1
the allowable 10 I for the section to be tested and the client or his agent shall willess and sign the results of the test
able 13 Air leakage rates
Maximum leakage of duct work Static
prcssUft Low-pressure edium-prc-sure I Iigh-prebull me diJfercntial Class A Class B Class C
1 2 J 4 Pa Litres per second per quare metre of surface area 100 054 018 ZOO 084 028 300 110 037 400 132 044 500 153 051 600 058 019 700 064 021 800 069 023 900 075 025
1000 080 027 1100 1200 1300 1400 1500
029 030 032 033 035
1600 1700 1800 1900 2000
036 038 039 040 042
Note Recommend d mean test presures are highlighted iD bold type with the actual selection being left to tll test operator
50
DW154 Sfeeiieaioll for Plastics Ductwork
A9
A10
and air leakage classification for the y em under test
DESIGNERS CALCULATIONS The designer can middotaJculate with reasonable accuracy the predicted total loss from a ystem by
a) Calculating the operatin presure in each ection of the sy tern
b) Calculating the surface area of the ductwork in each correspondin pre lire s ction
c) Calulating the allowabl~ los at the operating pressure for each ection of the system (see table 13 for allowable leakage figures)
VARIABLE PRESSUR S IN SYSTEMS De igner can achieve significant co t saving by matchina operating pressures throughout the system to constmctional standard and appropriate air leakage testing eO the practice of specifying construction tandards for whole duct sy tems based on fan discharge pre sure may incur unnece sary costs on a project For example ome large sy terns ould well be classiC ed for I akage limits as follows
Plant room risers CJas C Main floor distriblltJou CIa B Low pre sure outlets Cla A
A6 SPECIAL CASES There may be ~itLlations on a project where circumstance dictate thal pecial consideration be given to containing air loss s eg a long mn of duclwork may incur a di -proportjonate level of air 10 s In ca es such as thi example the designer can specify an improved tandard of airtighmess ie 80 of alJo~able 10 s for la B Ju ts The designer sbould not specif a CIa C t sI at CIa s C pressure for a CIa s B ducl
A7 SUGG S ED RANGE OF TES ING
A8 TESTING OF PLANT ITEMS Items of inline pJant (eg Fig 106 to 115) will not normaUy be included in an air I akage test The dllctwork contractor may indud such itelllS in tbe te t jf rh quipm ot has a certificate of COnfOlnlity for Ihe pres ure clas
bull High pressure duct bull Medium pre sure ducts bull Low pre sur ducts bull Exposed extract syst ID bull Ceiling void extract
systems bull Secondary ducts from
VAV or fan coil units bull Flexjble duct bull Final connections and
branches to grille and diffusers
100 test See A5 Untested UDt sted
Untested
Untested Untested
Untested
SI
i
DW154 SJecijicafion for Plastics Ductwork
ig 116 Permitted leakage at various pressures
Leakage in litres per second per square metre duct surface area
Vgt
o ltgt 0 ltgt N
ltgt Cgt
0 0 cc
0 0
~
g =
g ~
c 0
J
ltgt 0 I
~ ] tn
ltgt ltgt
In ol
~ 0 ~ 8 ~
~
c ltgt ltgt
~ CJ
~ ~ ~ ~ 8
0shyij
~ ~ ~ t
ltgt ltgt 00
l
~
~ Q
c C
~ rshy
e ltgt
I 1
I Cgt ltgtv
c Co ~
~~ ~ 10
I
0 Cgt
fJshyq 410 ) 1 ltgt
ltgt N
~ shy ltgt ltgt
~ I 1
c
52
DW154 Specificatio for Plastics Ductwork
Example of a completed test sheet Test No
General
Name of job N~ jC43Pt(r2lef Building Repound ~(~~0
Part 1 - Physical details
a Section of duct work to be tested ~(diffPIfff~el1f3rd Floor
b Drawing Number g91~~ c ssure aSSJ L atlOn V~Jl~IRfYgtg~~lPre Cl T Class C
d Test static pressure -(9 raErq~ ~~~~-~~J~~~ ~~ ~~~~ll
Leakaoe factor 9~-tre3$ecMz I OM REFTOTABLE 13)e b bullbullbullbullbullbullbull
f Surface area of duct under test Q~tJJItetre$ CPROMCALCU TIO BELOW)bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull ampampamp bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull
g ]Vlaxi mum permitted leakage -~ (~i~~0 ~~r~~ ~~~l-~-11~ ~~~Q
Part 2 - Test particulars
a Duct static pressure reading 9QFt~q~ ~ middot~~~1 ~~
b Manufacturer and type of liow measuring d vice (-~~~cJ~Y-9Q7EYg c Range of measurement of now measuring device QtP)OQ~(e~~~0I~~~~1~I~ ~~~~~~W~
d Reading of flm measurin o device pmiddot IFROM RIO)ftscag ~
I (DERlVED [ROM CHART SUPPUED WITH RIG US 0 ud)1e Interpreted air flow leakage rate ~(~~~f~~~ (~l~~~~~~~~~~~~~~~~~I
f Duration ~~~~~norn~allY l~ lnil1Ut~~d~~~ it1~ W~ Date of test ~(lITled ut by Wltll s ed by ~ ~
(~lJ MIJLrr) (Si~rrfltJUYJ
Printed Name 1~g0f~ Printed Name ~~Y~9~ and Company 7jl~~~~~( UJd CompanY AB COII$Itallt8
Width and depth or diameter
Periphery ength Area
millimetreS millimetres metre qL1are metre
800 x 750 3100 1755 5440
600 x 650 2500 557 1193
300 x 300 1200 120 144
305 din 958 700 670
250 dia 785 450 353
TOTAL 8000
53
DW154 Specijilarion for Plastics Ductwork
pA XB
Guida ce No es For he ransport Handling and
Storage of uctwork
avoid damage to adjacent duct panels In somc ca es particularly on con acts calling f r repetitive sizes the use of timber jigs and spacers may be justified Where reduced bulk and greater protection are major factor such as consignments for export transporting ductwork in L shape sections may justify the increa ed ite as embly co ts
It is recommended that before a contract is finalised that consideration is given to the subject of site acces material handling and storage as tbcy havgt a strong influence on the cost efficiency of the overall activity of ductwOlk installation
B3 Handling To minilnise th risk of damage duct sections should be clearly identified and deliveries to site should be closely linked to the installation programme so as to avoid accumulation of
B1 Storage and Handling of Ra Material Material should be stored in suitably designed racking out of direct unJight Where possible the e racks should be metal to earth Edges of cut she t may be harp and protective gloves are advised Wearing teel toe-capped boots is recommended Most pIa tic sheet is manufactured with smootb mfaces andor is suppLied with protective coating Care must be taken to prevent accidental lippag of stacked materials Beiuoshy good electrical insulators the movement of stock unless earthed will allow the build up of stati All stock shapes are chemically stable at normal temperature Whil t some raw materials used in their manufacture may themselves pre ent a toxic hazard once incorporated into the lOck bape they no long r constitute such a hazard and no dermatitic bazard are known nor are any
unfiJied ductwork and minimise double handling It is important to recognise that ductwork panels joint and corners arc susceptible to damage and care must be taken wheu band ling such material through a site During handling individual item of duct work may be liable to light cross sectional deformation until thev become an integral pan of a completed ductwork system Whilst this may temporarily detract from its intended appearance thi deformation will not have any detrimental effect on the functionality of the finally a semblecl system Installation of duct work and asociated plant items ill illevitably involve manual handUng The responsibi Iiry of employers and employees to a ses the risk of personal injury during mallual handling operations is et out in the HS E publication L23 Guidance on Manual Handling Regulations 1992
environmental problems expected 84 Site storage
B2 fransport Large capacity vehicles with high-sided open or closed-top bodies are tlle mo t suitable for the transport of dllctwork Careful consideration should be given to the
Adequate floor space IDust be provided within tbe building for the site storage of ductvork Such storage shalt make due allowance for thc stOf(ne of ductwork in stacks such that access ~ egt
between them is of sufficient width to pennil the removal of item without interference to
unloading of transport on sit a not all siJes b n fit from the material handlino- and access facilities that exi [ in a manufacturing workshop such as crane- fork-lifts or loading bay Site handJiog facilities along with
adjoining sta ks Ductvork components should be positioned so a to avoid crushing Ductwork of small panel size may be stored horizontally however care should be exercised to ensure that tack sizes are limited 10 within
ehicular acce s restrictions may itilluence the type and ize of transport to be uWised
engtlls of ductwork should be positioned 0
the tmctural strength of the duct sections to prevent distortion of the lower sections within the stack
as to avoid crushing Lengths Witll projections such as branches and bends i1anges girths damper quadrauL should be loaded so as to
54
DW154 S1tciic(ltioll for Plastics Ductwork
85 Internal cleanliness of new ductwork The site storage of ductwork introduces the important cODsideration of maintaining the internal cleanliness of the ductwork R feren e should be made to HVCA documentshybull DWffM2 Guide to Good Practice - internal
Cleanliness of New Ductwork Installations If the above conditioDs can not be satisfied consideration should be given by tJle designer to amending the specification to include for Po t Installation Cleaning as covered by tJ1C HVCA documentshybull TRJ17 Guide to Good Practic - Cleanliness
of Ventilation Systems
APPE DIXC
Fi e Retardant inishes C1 Improvement in the fire retardancy of plastic
ducts can be achieved to varying degrees and is wholly dependent llPOll the surface coating laminating resin selected and construction specification adopted In some instances smoke emission is coILSidered equaUy with other speci fication requirernen ts of the materials resistance to ignition and bumjng It is therefore important for design rs to establ ish the clients and officers detailed requirements and not rely on a tbird party interpretation of fire resisting or fire retardant Where possible the specification should refer dir etly to compliance with a British or European Standard identifying the specific sections applicable There are various types of resin and mat rcLnforcements that can achieve a Class 1 surface spread of flame ratin o when tested according to BS476 Part 7 (1987) This test puts materials illto Class I - 4 in descending order of perfoDllance according to the rat and extent of flame spread over their surfac under standard beating conditions Materials should also be tested for flre propagarion to BS476 Part 6 (1989) Tbi tesr measures the amount and rate of heat evolved by the material when subjected to standard heating
conditions Test results are given as an index of Perfonnance (i) whicb is based on three sub indices (iJ (i1) (h) The higher the value of the Index of Performance (i) the greater is the material s contribution to fire growth The higher the value of the sub-index 0) rhe greater the ease of ignition aod flame spread The highest product performance classification as defined in Approved Document B of the Building Regulations is Class O This is acLlieved if a material surface of a composite ploduct i~ either a) composed throughout of materials of
limited combustibility or b) a Class I material which has a tlre
propagation index (i) of not more than 12 and sub-index (i l ) of nor more than 6
01 J Class 0 is not a cla$sif1cation identified in any British Standard test
There are resin system reported to be classified to Class O when tested to BS476 Pcl1S 6 and 7 however designers need to ensure that such sysrems can be applied to their proposed design In propriety resinmat system available the fabrication techniques and COITect application are critical to the integrity of the reinforcing and clas ificatiol1 For example in some systems the u e of a non-fire retardant gelcont on a fire retardant substrate would reduce the classification For further information see HVCA publication DW144 Appendix D
55
DW154 SplCijiClIliol1 for Plastics Ductwork
x Guidance otes For nspectmiddoton Servicing a d
Clean-ng Access Openings
D1 GE ERAL This appendix highlight in ummary fOI111
the acce considerations that hould be made by the design r iD terms of inspection servicing and cleaning Having considered the seop and the design of the dUCI work system relative to the guidelines outlined below the designer should clearly indicate which levels of acces should be incorporated into the manufacture of a new duct work system (See Table 14 and Note I b low it
D2 DESIGN CONSIDERATIONS
D21 In ptction and servicing requireshyments are set out in Section 15 of Lhis specification
D22 Cleaning requirements are set out in the HVCA pubUcation TRl7 Guide to Good Practice Clean Lines of Ventilation Systems and the guide tates The precise location ize and
type of access would be dependent on the type of ductwork cleaning inspection and te ting metbods to b adopted Care protection and standards of cleanliness prior LO cOlllmisionin o
are set out in th AV A publication DWITM2 Guide to Good Practice Internal Cleanliness of New Ductwork Installations and th guide state Wh re specific limits of cleanliness are required ductwork sball be cleaned after installation by a spcialist cleaning contractor It will b in the interests of tht desioner botb financially and practically to cunsider employing a specialist c1eauing contractor at tbe
outset of a contract to internally clean newly installed ductwork prior to bandover This approach would reali e the following benefit shyi) Tb actual numb r of cleaning
access panels could be detennined to suit the method of cleaning to be adopted (This may be 1 s than the maximum requiremen listed under Lev 13 of Table 14)
ii) Clear directions could b given to the ductwork contractor as to tJle size and location of cleaning access panels that are required to be fitted during the mauushyfaclunng pro s
iii) The specialist cleaning operation prior to commi ioning vould enable the cleaning contractor to verify the practical acee requirement for the future cleaning operation associated -vitb a regular maintenance programme
iv) A specialist cleaning operation prior to commissioning would allow the designer to omit from the speeilicatiolJ the DWrrM2 requirem nt for factory sealing protection wipe downs and capping-off
v) Specialist Ieall ill 0 to the measurable standard defin d in TR17 will allow an objective definition of cleanline to be achieved
Car ful consideration must be gIven by the designer to the practl aJ problems associated witb the manufacture and fitting of suitably si Led access panel on small cross section duct and on the circular faces of rouod and flat oval ducts in particular
D23 Special con ideration must be given by the de igner to the practical problems associated with gaining personnel access to heavily congested ceiling areas and multi-la red du twork systems This approach would avoid
56
DW154 Spfciication for Plastics Ductwork
the possibility of access panels being D3 ACCESS 0 IN-LINE EQUIPMENT incorporated into a ductwork system at the This appendix unly covers acc il1spection manufacturing stage that were later found in through the ductwork body adjacent to an item practice to be inaccessible for either ervicing of in-line equipment and not openings in the or cleaning activities equipment itself
able 14 Acce requirements for inspection servicing and cleaning
HVCA PUBLICATIO REFE NeE (uidtgt 10 Gund Prartict
Adjace t OW144 Cleanliness orVcnlillltio S~lcr~ fRjJ7
in-line LeyeJ 1 Level 2 Level 3 ite sequipment pcdionSen lcin~ Section d C1eaniJl( SUn(O)lnspc lion Palle ltk~m_n
2011 (minimum OiL Jubje-ct to duct ~zel (ft~ -Panels
Control Da pcrs One (inspection) 203 One 300 mm x 200 mm Both sid Fire Dampers One (sCTjdJl~) 20211 One 300 0101 x 200 mm One side HeatingCooling Coils One (inspedion) 20213 One 300 mm x 200 mm (lIpstream) Both sides Attenuators (rectangular) None required One 300 mm x 200 mm (downstream) Both sides Attenuators (circular) one retluired One 300 mm x 200 mm (downstream) One side Filter Sections One (inspection) 20212 one required Uoth sides Air Turn Vanes None requjred None required Both sides Changes of Direction None required one required One side In-Duct FansDevices One (inspection) 20213 None required Both sides l
1 In the absence of any indication by the designer only Level ) access will be jncorporated into a new ductwork system
2 Tbe panel izes associated with Lev lis I and 3 acee s ar e middottablished by reference to Section 20 of DW144 and Section 2 ofTRll7 respectively
57
DW154 Speclfifatio for Plastics Ductwork
pA XE
B-bliography Included in this Bibliography are technical pUblications which may be of interest (0 ductwork designers fabricators and erectors and to tho e in the heating ventilatlng air conditioning industries generally nquiric should be made of the relevant organisation at the address quoted Since its publication other addresse contained within 0V154 mav have changed and some pubJicalions may have been superseded
HEATING AND VENTILATING CONTRACTORS ASSOCIATION
4 Palace Court London W2 4JG Telephone 020-7229 2488 Fax 020-7727 9268
Orders fo FlY A Publications Old Matlsion House Eamont Bridge Penrith Cumbria CA 10 2BX (Telephone 01768 864771 Fax 01768 86718) Email hvcapoblicationshvwelfarecouk DWn 44 pe ilicatiun for sheet mctal duclwork (Iow- mediulllshy
and high-pressure) 1998) DWIl4 A practical guide to dUGI ork I akage te ting
(revised 2000) DWII54 Specification for plastic~ duct rk DW171 Guide to good Practice for kitchen venlibtion system DW191 Guide to good pracuce glass fibre ductwoJk DwrrMI Acceptance cheme for new products - Redangolar cro
joint classification Guide to good pra tice - Internal cleanliness of new ductwork installations Guide to good practice for the design for the Installation of lire and smoke uampers
J 1Other puhlications
HampV safely guide 5th edition JS2 Tool box talks JS5 Weldlng Safety booklet JSI9 afety facts bo klet Fact sheets 1-24 2nd edition JS2J COSHH manual volume 1 Advice on compliance with the
regulations 1521A CO I-rH manual volume 2 Asses mcnt h ets JS23 Ri k management manual TR3 BrazinltT and bronze welding of copper pipework cUld sheet
(I 976) TR5 Welding of carbon steel pipework (1980)
TR6 Guide to Good Practice for Site Pre sure Testing of Pipework (19 0) Guide to good practice cleanliness of ventilation Ylem
CHARTERED IN TITUTlO OF BUILDING SERVICES E G EERS Delta House 222 Balham High Road London SW12 9BS rTelephone 020-8675 5211 Fax 020-8675 5449) CIBSE Guide Volume A Design Data Volume B In tallatiol1 and quipment Data Volume C Reference Data
CommlssioniJIg Codes These Codes eover the preliminary checkS eUing to work and regulation of vanous catcgories 0 plan The Codes give a guide to design implications Series A Air Distnbution Systems Series B Boiler Plant
ri s C Automatic Conlrol ystems Cr1es R Refrigerating Sy terns
Sene iN Water Distribution Systems
Technkal Memonllda TM 4 Design Notes for the Middle East TM bull Design otes for Ductwork TM 13 Minimi iog lhc Risk of egiounaires Disease
Research Reports RROI95 Ventilation system hygiene - A review of published
infomlatioo on lhe occurrence and ffects of Olltamination Rl~02J95 Air-to-air heal rec v ry RR0395 rnfluen e of HV C on smoke detectors
ATlONAL ENI [ERING SPECIFICATION LfMITED Southgatc hamber 3739 Southgate Street Winchester S023 9EH (Telephone 01962 842058 Fax 01962 R(8982) BUfLDING S RVICES RESEARCH AND [ ORMATION ASSOCIATIO Old Bracknell Lane West Bracknell Berkshire RG 12 4AH (Telephone Brackl1eU (01344) 426511 Fax 01344 487 -7 )
Application Guides AGln4 De tglJing Vana~le Volume middotylans for KOOnl
iir Movement AG1I91 Commissioning of V Sylcms in Buildings 11 6194 Fire Dampers
B) 94 cntiJalion or KitcneTls
AG389 The Commls ionin of Air Systems In Buildmgs AH2192 Commissioning of Bern - A ~ode of Practice TN2417 I Fire Dampec il) Ventilating Ducl
BEATING VENTILATING A AIR CONDITION G MA UFACTURERS ASSOCIATIO (HEVAC) HEVAC Henley Road Medmenham Marlow Buck SU 2ER (Telephone 01491 578674 ox 01491 575024 Emoimiddot infofetacouk)
Publicatjons Air Diffusion Guide Guide to Air Handling Unit Leakage Testing Guide to Good Practice Air Handling Unit Real Room Acoustic ~ st Procedure Specification for the ertiiicatioll ofAir Filters Method of Test for Water Rejection PerfOnTlatce of Louvrcs Subjected 1(1
Simulated Rainfall Test Procedure for Acoustic Loo cs Specification 10 Floor GrilJes - Types Performan e and Method ofTest Specification for the Determination of the Collection Efficiency of SilJ1d
Trap Louvre Domestic Mechwlical Vclltllalion Systems with Heal Recovery Fan Application Guid
~an and Ouctwork Installation Guide Guide to Fan Noise and Vibration
pecification of Requirements for JallJral Smoke and Heal Exhausl Ventilators
pecification for Powered Smoke and Heat Exhaust Ventilators
Specification of Requirements for Smoke Curtains Design Gujue of Smoke Ventilation for Single Storey Lodustrilll Building~
Including those with Mezzanine Floor and IIi Racked Storage Warehou es - Issue 3
Guidance for the Design of Smoke entilation YSlem for Covered and Undergrollnd Car Parks - lssue 1
Application of SOloke Control Equipment and Syst m Guid to Good Practice - Isue J
58
DW154 Sp(C~tiifitiol for Plastics Ductwork
BRITISH STANDARDS INSTIT TION Sales Department 101 P ntooviLle Road London NI 9ND (felephone 020-78 1 78801)
CP 413 1973 Ducts for building ervices
SS 476 Fire tes on building matenals and lruc(ure
Part 4 19 4 Non-combustibility lest or materials
Part 6 I Fire propagation lest for materials
Part 7 1993 Surface spread of tlarnJ tesls for materia
Part 20 1987 Fir resistance of elements of construction
Part 21 1987 Fire r sistlUlce of loadbeanng elements of construction
Part 22 1987 Fhe istallceofllon-loadbearing elemcllts ofconsttuclion Part 23 1987 Contribution of componcnts to the fire resistance 0 a
structure
Part 24t987 Fire resi lance of wl1lilation ductl
SS 5588 nan 919 0 Fire Precautions III thc desIgn and OOSlnJ lion of buildings
S 729 1971 Hot dip galvanized oatiugs (or irOIl aod stcel articles
BS 1449 Steel plate sheet and Irip
Pan 11991 Carbon steel plate heel and strip Part 2 1983 Stainless steel plate sheer and strip
and
B middotENJOI49-2 996 BSEN 10149- 1991)
BSEN 10131 1992
BSEN22063 Sprayed metal coarings 1994 Protection of iron and steel by aluminium and zinc against
atmospheric cOlosion Irotectiotl of iron and ste I against corro ion and oxishydation at elevared temperatures
BS 353 1981 Glossary of lerms relnting to thermal insulation
BS ISO 1479 Self-tapplngscrewsandmetallicdri c crew
B -lSO 7049
1994
B 4800 1989 Painl colour for building purposes B 4848 l0 rolled structural steel sections
Part4 1972 Equal and unequal angles BS 5422 1990 Specification for the use of therm illuating matcriulS
SS 5720 1979 ode of practice for mechanical veutilating and air C 11shy
dirionin bull in building
l3S PR 12814-1 Bend resting for plasric welds
SS PR 12814-2 Tensile testing for plastic welds
SS PR 13067 Appro altesting for plastic welds
BS PR EN I 100-] Vi ual in pection ofplaslic welds
SHEET METAL AND AIR CONDITIONING CONTR-CTORS NATIONAL ASSOCIATION INC (SMACNA) Headquarters 420 I Lafayeue Center Drive Chanlilly Virginia 2051-1209
Mailing Address pa Box 221230 Cbantilly Virginilt120 153-1230
Telephone (703) 803-2980 Fax (703) 803-3732
Accepted IJJdustry Pl3Gtice for Industrial Duct Constnlelion 197 ) i-rchitecmral Sheet kwl Manual ([993)
Comractors Guide lor Modification 10 ooslruerion Colllraets 1993 Ducted Eleclric Heat Guide for ir Handling Ssrerns (1994)
En~rgy ollservatioD Guidelines (1984) Energy Recovery Equipment yslClllS (199l
Fibrou GIns Duct onS1ntClion Standards (1992)
Fire Smoke amp Radiation Damper In tall Guide for HVA Syst ms (1992) Guide t leel Stack 1(95)
HVA Air Duct Leakage Test Manual (19 ) HVA COlllmissioning lvlanual (1994)
H A Duct Construction Standards-Metal amp Flexible (1995) Addendum 01 (Nov 1997)
HVA Duct Systems Inspection Guide (1989)
HVA ySlems-Application (1986) nVAC ByternS-DLlct D ign (1990)
HVi Systems-Testing Adjusting amp Balancing (1993)
indoor Air Quality Manual (1993) tcheu quipment Fabrication Guidelmes (1990)
Managers Guide for elding (1993)
Rectangular Industrial Duct Cons1TUction Standards (19 0) Round Industrial Duct oustmction Standards (1977)
Sei mic Restraint Manual (1991) (wl Appendix E 1993) SMACNA Ma le Index ()fTechnical Publications (1995) Tbennoplnstic Duct CPY ) Construction Manual 1994)
DEPARTME OF THE ENVIRO MENT (Publications Centre) H Stationery Oflice 5 Nine Elms Lane London SWS 5DR
MampEJ 011972 Electrical in tallat1011 in buildings ( ew Editiou)
IampE 0319 Healing hot and cold wat r steam and gas losla1lations for buildings
M amp - No4 1970 Central heating and hot and cold ~ ateT in tallations for
dwelling
M amp ENo100 1971 Mechanical ventilation for building~
ASSOCIATION FOR SPECIALIST FIRE PROTECTlO As ociation House 235 Ash Road AJdershot Hampshire GUl2 4DD
Telephone OJ25221322 Fax 0 J252 333901
lublicalioos Fire Ratcd and moke Outlet Ducrwork An Industry Guide t Design and InSlalla lioll
HEALTH AND SAFETY EXEC TIVE Rose Court 2 Southwark Bridge London SEl 9HS Telephone 020-7717 6000
TWJ THE WELD G TlTUTE Abington Hall Abington Cambridge CB16AL Telepbone 0 J223 89162
Publication DatJ Oil w~ldll1g of lhermopla lics
59
DW154 wciiwlioll for Plastics Ductwork
A -=--DIX
Factors
Specific gravity shy pp = 091 approx UPVC = 14 approx
Some miscellaneous conversion factors
To convert
Length Inches to millimetres Feet to metres
Multiply by
2540 03048
To convert
Millimetres to inches Metres to feet
vIultiply by
003937 3281
Area Square inches to square millimetres 6452 Square millimetres to square inches 000155 Square feet to square metres 00929 Square metres to square feet 10764
Volume Cubic feet to cubic metres Cubic feet to litres Gallons (UK) to litres
002832 2831 4546
Cubic metres to cubic feet Litres to cubic feet Litres to gallons (UK)
35315 00353
022
Mass Ounces to grams Pounds to kiJograms Tons to tonnes
2835 04536
1016
Grams to ounces Kilograms to pounds Tonnes to tons
003527 2205
09842
Volume flow Cubic feet per minute to cubic Cubic metres per second to cubic
metres per second 0000472 feet per minute 2119 Cubic feet per mIDute to litres Litres per second to cubic feet
per second 04719 per minute 2119
Motion Feet per minute to metres per second 000508 Metres per second to feet per minute 197
Pressure Inches water gauge to millibars 2491 Inches wateJ- gauge to pascals (Pa) 2491 I Pa = I ewton per square metre = 10-2 millibars
60
Heating and Ventilating Contractors Association Esca House 34 Palace Court London W2 4JG
Tel 020 7313 4900
e-mail contact Itvcaorguk web site wwwhvcaorguk
Fax 020 7727 9268
---
DW154 Spedicatioll for Plastics Ductwork
STANDARD OMPONENT DRAWINGS - RECTANGULAR
DRAWING DETAILSFIG
64 on-Return DamperNRD shyshy
shyXbull
Multi-Leaf Damper Can be piggoted or flanged oppo cd or parallel blade
Alternative controls areshy
q p [gtshy
J HD65 Hand
~MD otori ed
PO Pneumalic
L-lt
l 13G 66 Blast Gate DamperX X
FireSmoke DampersSleeves
211r Ratinggtshy----
L_-
---
----
r----
Ir-- shy
IL- _-l
2hr
With i tallation frame
67 41 r Rating
4hr
Smoke damper SD
Intumc cent Sleeve L-d
37
DW154 Specijicutiolt for Plastics Ductwork
FIG
68
69
70
71
STANDARD COMPONET DRAWINGS shy REC ANGULAR
DRAVING DETAILS
gtshy Access Openings
AP 6 Access Panel - Rerno able
w [ ~ Access Door - Hinged
I ~le Inspection Cover
le -I reg -lt
~X X Flexible Connection
~ Drop Cheeked Radiussed Twin Bend
U Drop Cheek Bend
I
72 Air Flow SymbolX
38
DW154 Specifim[ioll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - ECTANGULAR
FIG DRAWING DETAILS
73
74
75
76
77
Q
Q
rp---t
~
V- I Ir---I
JL --11
THE ABOVE DETAILS TYPICAL PLENUM
Air Terminal Plenums
Plenum with side connection
Plenum with top connection
Cover plate with connection
Special plenum with connection
elescopic conn ction in direction of air flow
39
DW154 SpecijicotiOll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG
78
79
80
81
DRAWING
-23~---pound3-(MALE) (FEMAJE)
-t=j--_j(--d-shy
--L
~ THROAT RADI S= D AS T NDARD
e ~
THROAT Rjf)lU = D A MU)
DETAILS
Straight Duct With male and female connectors
Straight Duct With flange joint and slip joint
Bend MouldedIFormed Applies to any angle ego 30deg45deg60deg90deg Medium radius bend as illustrated Long radius similar but throat radius 0
Segmented Bend 90deg four section minjmum as illustrated
Other Angles 60deg = 3 sections 45deg = 3 sections 30deg = 2 sections
I
i
40 shy
DW154 Speciicafinll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG DRAWING DETAlLS
82 Segmented Twin Bend Radius = D2 max
May also be fabricated from tube
83 Equal Tee MouldedIFormed
84 -~ 1in Bend MouldedIFormed
85 Taper Concentric 1 0 as iUu trated Eccentric 30deg iJJcLuded angle
86 Short Taper
41
DW154 SpcUicatol1 for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG DRAWING DETAILS
87 30 max Offset
Angle Branch
Bran h dUCI Dimcnsions dia (D) lA)
Shoe Branch mm mm 88 Cl
Off rectanguJur Up 10 200 75 lOO 10 400 125
- 00 150 Over 600 200
Bl1IllCh duct DimenlOns din (D) (A
~-$a-Conical Branch mm mm
89 Also acceptable with Up 10 200 r
full conical surface 300 10
400 125
END VrE -shy 600 150 Over 600 200
90
m 75
100 12 150 200
mm Up to 200
_ 300 400
600 Over 600
iUtred Branch
Shoe Branch
J-L----U ~ Bell oulh Branch
ENDV1EW
93
92
91
42
DW154 Specificatiol for Plastics Ductwork
STANDARD OMPONENT DRAWINGS - CIRCULAR
FIG
94
DRAW G
I
~ 30deg 090deg
Breeches Piece
DETAILS
95 amp-----~ Blank End
~-----p Multi-Leaf Damper Can be piggolcd or fianged opposed or parallel blade
Alternative controls areshyri=-+- L-T~
I
---
LT~
I r- -
-+1
J HO Hand96
bMD Molori cd
PD Pneumatic
tl-shy bull
Single Bladed Damper 97 ~ saD
on-Return Damper Vertical application only 98 m~D
43
DW154 Sf1tcificatioll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG
99
100
101
102
DRAWING
$ I-
2hr
1 4hr
SD
~v I I
CO TINENTAL COWL
DETAILS
Iris Damper
Fi reS moke Dam persSleeves
2hr Ratillg
With installation frame
4br Rating
Smoke damper
Intumescent Sleeve
Access Openings
Access panel - removable
Access door shy hinged
fnspection cover
Discharge Continental Cowl
44
DW154 Sp(Cii(ltJll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
DRAWINGltIC DETAns
-
I
I
~
I I I High Velocity Discharge Terminal 103 I
I
I I
J I I 1 ~--
Offset Stack Discbarge Terminal 104 1
~ I e --(-
I
N
I
I
I~
I I Vertical Oischarge with Weather Cowl 105 I
--1--1 I
I
GAPI I
RTl AL DISC) lARGE WITH W ATIIER COWL
45
DW154 SpecUicatoll for Plastics Ductwork
STANDARD COMPONE T DRAWINGS - PLA TEQUIPMENTIMISCELLANEOU
FIG DRAWING DETAILS
106 ~~~ Rectangular Attenuator
107 ~- Circular Attenuator
108
~ Beod Attenuator
109 J ~(f) Heating Coil
110 J ftte Cooling Coil
III Jc[ Electric Heating Coil
112 X F
Humidifier
113 [H XX Axial Fan
114 ~fB1famp Noo-standard Ductwork Cross hntchillg (of any separate type) indicates by reference to a key any non DVil54 ductwork system
115 2llIIIIJIIIIIll Flexible Ductwork
46
DW154 SJeCUicll(iol1 for Plastics Ductwork
TABLE 12 - STANDARD ABBREVIAT ONS
ABBREVIATION FLL
AD Acces Door
AFF Axial Flow Fan
AHU Air Handling nit
All Aluminium
AP Acess Panel
AT Attenuator
AV Air enninal Unit
BE 81ank nd
BQ Blast ate Damper
CC Cooling Coil
CF Centrifugal Fan
CTA Cross alk Attenuator
CVU Constant Volume Unit
DP Drain Point
EEC Electric Heating Coil
El Expansion Joint
FAl Fresh Air Inlet
FA From Above
FB From Belo
fBPP Fabric Backed Polypropyl-ne Sheet
Flexle Flexible Connection
lexfD Flexible Du t
C False Ceiling CO an oil Unit
fD Fire Damper
FFL Finished Floor Level
FJ Flanged Joint
FOAM Rigid Polyurethane Self xtinguishing Foam
FOB Flat on Bottom
FOT Flat on Top
GAM Galvanised after ManufacttrJc
GRP Glass Reinforced Plastic
GSS Galvanised Sheet Steel
HC Heating oil
HD and controlled Damper
HH Hand Hole
HL High Level
HVD High Velocity Discharge
IC Inspection Cover
ID lri Damper
IFS Intumescent Fircleevc
47
DW154 Specification for Plastics Ductwork
TABLE 12 - STANDAR ABBREVIATION CONTINUED
ABBREVIATION
IU
L
tv1D
MS
NRD NTS
OBO
OE
PHD
PD
PP
PP
PRD
PVC
RFC
RSC
R
SBO
SO
S1 TST
SSL
TA
TB
TO TJ
TP
TV
TV
OS
UPVC
S
V
VAV
50 RSA
FULL
Induction Unit
Low Level
Motor controlled Damper
Mjld Steel
on Return Damper
at to cale
Opposed Blade Damper
Open End
Parallel Blade Damper
Pneumatic controlled Damper
Polypropylene
Self xtinguishing Polypropylene
Pressure Relief Damper
Polyvinyl Chloride
Rolled Form Chamlel
Rolled Steel Channel
R fUnit
Singl Blade Damper
Smoke Damper
Slip Joint
Stainl t el
tructural Slab Level
To Ab vc
To Blow
Top Down (In Direction of Flow)
Telescopic Joint
Test Point
TU111iog Vane
Top Up (In Direction of Flo )
Voles Otherwise Stated
Unpl3sticisecl Polyvinyl Chloride
Underside
Ultra Violet Light
Variable Air Volume
Rolled Steel Angle (Vith Size)
48
DW154 SJeriiflllioll for Plastics Ductwork
A2 DUCT PRESSUREAPPE DXA Ductwork con truct d to DWIl54 will bebullbullbullbullbullbullbullbullbullbullbullbullbullbull
Air Leakage From Ductwork To be read in conjunction with DW143 A practical guide to Ductwork Leakage Testing
CAUTION As highlighted ill both this docul1lenr and DW14 I lot ellough emphasis can be placed 01 the fact that except for high pressure class C the much more stringent ductwork constructional standard brolght about b the general acceptance of DW154 have irtlally negated the requirement for leakage-testing It is essential lO realise lhat except where it is mandatory this doclllllelll is nOl an endors ~lIlent of the rourine testing of ducts bllt purely a guide to outline the procedures for cononnity with the air leakage limits ill Table l Where the specified methods of assembly and
A3sealing of dlcls are u ed a vi ual inspection wil ordinarily sl~fll e for ver(iatioll of a well engineered and a ceptahfy airtight COl1strucrioll WHERE NOT MANDATORY DUCT LEAKAGE TESTING IS GENERALLY AN UNJUSTIFIED AND SUBSTANTIAL EXPENSE
A1 INTRODUCTION L akage from ducted air distribution systems is an Lmportant consideration in the design and operation of ventilatjon and air conditioning middotystems A ductviork t)ystem tbat ba limited air leakag within defiucd limits wiH cnsUft
that tile design characteristics of the sytem can be maintained It wilJ also ensure that energy and operatLonal cosb are maintained at optimum levels DucLwork constlucted and Ulstalled in accordance with DW154 should minimise a level of air leakage that it) appropriate to tll operating static air pre sur in tile system
A4However it is recouuised that tbe environment in wtJich middotystems are installed is not always conducive to achieving a predictable level of quality in term of system ajr leakage and it is therefore accepted that designer may sometimes require tlle ystem to be tested in part or in total It should be ecogni ed that the testing of duct systems add a ignificant cost to the installation and incur some extra tjm within the programme (Se 47 and 64 re mandatory te-sting)
manufactured to a structural standard that is compatible with the system operating pressure There are three classes of duct con truction to eorre pond with the three pre ure clas meations Class A Lo pressure ducts suita le for a maximum positive operating pressure of 500 Pascal and a maximum negative pressure of -500 Pascals Class B IVledium pressure ductmiddot suitable for a rnaxilnuJJl positive operafjn o pressure of 1000 Pascals and a maxllnum negative pre sure of -750 Pa cal Class C High pre sure ducts suitable for a maximum po ilive operating pressur of 2000 Pa cals and a maximum negativ pres ur of -750 Paltcals
LEAKAGE FROM DUCTWORK Leakao-e front pia tic air ducts occur at the joint~ and is therefore proportional to the total surface area orthe du twork in th system Tb level of leakage i imilarly related to tIle air pres ure in th du t system and whilst there LS n precis formula for calculating the level of air los it i generally accepted that leakage will increase in proportjon to pressure to rbe pOvver of 065 The effect of air leakage from high pressure velocit ductwork is critical tn terms of system perfomlan dege energy consumption and the risk of high frequency noise as ociated with leakage These problems are le critical with medium pressure 10 ity systems but should be con idered Low pres mevelocity ducts present the lowe~t
ri k in tenn of tbe effect of leakage on the operation of the s stern
SYSTEM LEAKAGE LOSS As there i no di ct relatLonship between th volume of air conv yed and the surface area f the ductwork sy tern required to match the building configuratmn it is difficult to express air leakage a a percentage of total air volume Similarly the operating pressure will vary throughollt lh 3 system and a leakage is related to pre me the calculations ar comple However it is generally ac epted tbat in typical good quaJjty systems the leakage from
49
DW154 Specificatioll for Plastics Ductwork
each class of duct llnd r operating condition will be io the region of CIa S A low pressure 6 Clas B medium pres un 3 Clas C high pressure 2
A5 SPECIFYING AIR LEAKAGE TESTING Re peeting both the co -t and programme implications a sociated with te ling du 1 for leakage the designer may for example indicate that a particular system is te ted as follow
a) High pressure ducts - all tested b) Medium pr ssure duets - 10 of the
ductwork shall be s eet d at random and tested
c) Low pre sure - unte ed In any case where a random te t i elected for medium pre sure ductmiddot the followin c1au~e is suggested for inclusion by the de ign r
The designer hall elect at random a maxirnwlI of 10 of the dUCl system to bt tested for air leakage The duct hall be tested af the pressure recommended in Table J3 for the assifi atiol for the ectiol1 of the ductwork that is to be tested The tests shall be carried Ollt as the work proceeds and prior to the application of thermal insulation In the event of test failure of the randomlY selected section the designer shall have The right to select two La1her e tiolls at random for resting Where succes ive failures are identified there shall be a Tight to require rhl COl11raCWr 10 apply remedial attention to the complete ductwork system Th contractor shall provide documented eviden e of the calculalions used to arrive (1
the allowable 10 I for the section to be tested and the client or his agent shall willess and sign the results of the test
able 13 Air leakage rates
Maximum leakage of duct work Static
prcssUft Low-pressure edium-prc-sure I Iigh-prebull me diJfercntial Class A Class B Class C
1 2 J 4 Pa Litres per second per quare metre of surface area 100 054 018 ZOO 084 028 300 110 037 400 132 044 500 153 051 600 058 019 700 064 021 800 069 023 900 075 025
1000 080 027 1100 1200 1300 1400 1500
029 030 032 033 035
1600 1700 1800 1900 2000
036 038 039 040 042
Note Recommend d mean test presures are highlighted iD bold type with the actual selection being left to tll test operator
50
DW154 Sfeeiieaioll for Plastics Ductwork
A9
A10
and air leakage classification for the y em under test
DESIGNERS CALCULATIONS The designer can middotaJculate with reasonable accuracy the predicted total loss from a ystem by
a) Calculating the operatin presure in each ection of the sy tern
b) Calculating the surface area of the ductwork in each correspondin pre lire s ction
c) Calulating the allowabl~ los at the operating pressure for each ection of the system (see table 13 for allowable leakage figures)
VARIABLE PRESSUR S IN SYSTEMS De igner can achieve significant co t saving by matchina operating pressures throughout the system to constmctional standard and appropriate air leakage testing eO the practice of specifying construction tandards for whole duct sy tems based on fan discharge pre sure may incur unnece sary costs on a project For example ome large sy terns ould well be classiC ed for I akage limits as follows
Plant room risers CJas C Main floor distriblltJou CIa B Low pre sure outlets Cla A
A6 SPECIAL CASES There may be ~itLlations on a project where circumstance dictate thal pecial consideration be given to containing air loss s eg a long mn of duclwork may incur a di -proportjonate level of air 10 s In ca es such as thi example the designer can specify an improved tandard of airtighmess ie 80 of alJo~able 10 s for la B Ju ts The designer sbould not specif a CIa C t sI at CIa s C pressure for a CIa s B ducl
A7 SUGG S ED RANGE OF TES ING
A8 TESTING OF PLANT ITEMS Items of inline pJant (eg Fig 106 to 115) will not normaUy be included in an air I akage test The dllctwork contractor may indud such itelllS in tbe te t jf rh quipm ot has a certificate of COnfOlnlity for Ihe pres ure clas
bull High pressure duct bull Medium pre sure ducts bull Low pre sur ducts bull Exposed extract syst ID bull Ceiling void extract
systems bull Secondary ducts from
VAV or fan coil units bull Flexjble duct bull Final connections and
branches to grille and diffusers
100 test See A5 Untested UDt sted
Untested
Untested Untested
Untested
SI
i
DW154 SJecijicafion for Plastics Ductwork
ig 116 Permitted leakage at various pressures
Leakage in litres per second per square metre duct surface area
Vgt
o ltgt 0 ltgt N
ltgt Cgt
0 0 cc
0 0
~
g =
g ~
c 0
J
ltgt 0 I
~ ] tn
ltgt ltgt
In ol
~ 0 ~ 8 ~
~
c ltgt ltgt
~ CJ
~ ~ ~ ~ 8
0shyij
~ ~ ~ t
ltgt ltgt 00
l
~
~ Q
c C
~ rshy
e ltgt
I 1
I Cgt ltgtv
c Co ~
~~ ~ 10
I
0 Cgt
fJshyq 410 ) 1 ltgt
ltgt N
~ shy ltgt ltgt
~ I 1
c
52
DW154 Specificatio for Plastics Ductwork
Example of a completed test sheet Test No
General
Name of job N~ jC43Pt(r2lef Building Repound ~(~~0
Part 1 - Physical details
a Section of duct work to be tested ~(diffPIfff~el1f3rd Floor
b Drawing Number g91~~ c ssure aSSJ L atlOn V~Jl~IRfYgtg~~lPre Cl T Class C
d Test static pressure -(9 raErq~ ~~~~-~~J~~~ ~~ ~~~~ll
Leakaoe factor 9~-tre3$ecMz I OM REFTOTABLE 13)e b bullbullbullbullbullbullbull
f Surface area of duct under test Q~tJJItetre$ CPROMCALCU TIO BELOW)bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull ampampamp bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull
g ]Vlaxi mum permitted leakage -~ (~i~~0 ~~r~~ ~~~l-~-11~ ~~~Q
Part 2 - Test particulars
a Duct static pressure reading 9QFt~q~ ~ middot~~~1 ~~
b Manufacturer and type of liow measuring d vice (-~~~cJ~Y-9Q7EYg c Range of measurement of now measuring device QtP)OQ~(e~~~0I~~~~1~I~ ~~~~~~W~
d Reading of flm measurin o device pmiddot IFROM RIO)ftscag ~
I (DERlVED [ROM CHART SUPPUED WITH RIG US 0 ud)1e Interpreted air flow leakage rate ~(~~~f~~~ (~l~~~~~~~~~~~~~~~~~I
f Duration ~~~~~norn~allY l~ lnil1Ut~~d~~~ it1~ W~ Date of test ~(lITled ut by Wltll s ed by ~ ~
(~lJ MIJLrr) (Si~rrfltJUYJ
Printed Name 1~g0f~ Printed Name ~~Y~9~ and Company 7jl~~~~~( UJd CompanY AB COII$Itallt8
Width and depth or diameter
Periphery ength Area
millimetreS millimetres metre qL1are metre
800 x 750 3100 1755 5440
600 x 650 2500 557 1193
300 x 300 1200 120 144
305 din 958 700 670
250 dia 785 450 353
TOTAL 8000
53
DW154 Specijilarion for Plastics Ductwork
pA XB
Guida ce No es For he ransport Handling and
Storage of uctwork
avoid damage to adjacent duct panels In somc ca es particularly on con acts calling f r repetitive sizes the use of timber jigs and spacers may be justified Where reduced bulk and greater protection are major factor such as consignments for export transporting ductwork in L shape sections may justify the increa ed ite as embly co ts
It is recommended that before a contract is finalised that consideration is given to the subject of site acces material handling and storage as tbcy havgt a strong influence on the cost efficiency of the overall activity of ductwOlk installation
B3 Handling To minilnise th risk of damage duct sections should be clearly identified and deliveries to site should be closely linked to the installation programme so as to avoid accumulation of
B1 Storage and Handling of Ra Material Material should be stored in suitably designed racking out of direct unJight Where possible the e racks should be metal to earth Edges of cut she t may be harp and protective gloves are advised Wearing teel toe-capped boots is recommended Most pIa tic sheet is manufactured with smootb mfaces andor is suppLied with protective coating Care must be taken to prevent accidental lippag of stacked materials Beiuoshy good electrical insulators the movement of stock unless earthed will allow the build up of stati All stock shapes are chemically stable at normal temperature Whil t some raw materials used in their manufacture may themselves pre ent a toxic hazard once incorporated into the lOck bape they no long r constitute such a hazard and no dermatitic bazard are known nor are any
unfiJied ductwork and minimise double handling It is important to recognise that ductwork panels joint and corners arc susceptible to damage and care must be taken wheu band ling such material through a site During handling individual item of duct work may be liable to light cross sectional deformation until thev become an integral pan of a completed ductwork system Whilst this may temporarily detract from its intended appearance thi deformation will not have any detrimental effect on the functionality of the finally a semblecl system Installation of duct work and asociated plant items ill illevitably involve manual handUng The responsibi Iiry of employers and employees to a ses the risk of personal injury during mallual handling operations is et out in the HS E publication L23 Guidance on Manual Handling Regulations 1992
environmental problems expected 84 Site storage
B2 fransport Large capacity vehicles with high-sided open or closed-top bodies are tlle mo t suitable for the transport of dllctwork Careful consideration should be given to the
Adequate floor space IDust be provided within tbe building for the site storage of ductvork Such storage shalt make due allowance for thc stOf(ne of ductwork in stacks such that access ~ egt
between them is of sufficient width to pennil the removal of item without interference to
unloading of transport on sit a not all siJes b n fit from the material handlino- and access facilities that exi [ in a manufacturing workshop such as crane- fork-lifts or loading bay Site handJiog facilities along with
adjoining sta ks Ductvork components should be positioned so a to avoid crushing Ductwork of small panel size may be stored horizontally however care should be exercised to ensure that tack sizes are limited 10 within
ehicular acce s restrictions may itilluence the type and ize of transport to be uWised
engtlls of ductwork should be positioned 0
the tmctural strength of the duct sections to prevent distortion of the lower sections within the stack
as to avoid crushing Lengths Witll projections such as branches and bends i1anges girths damper quadrauL should be loaded so as to
54
DW154 S1tciic(ltioll for Plastics Ductwork
85 Internal cleanliness of new ductwork The site storage of ductwork introduces the important cODsideration of maintaining the internal cleanliness of the ductwork R feren e should be made to HVCA documentshybull DWffM2 Guide to Good Practice - internal
Cleanliness of New Ductwork Installations If the above conditioDs can not be satisfied consideration should be given by tJle designer to amending the specification to include for Po t Installation Cleaning as covered by tJ1C HVCA documentshybull TRJ17 Guide to Good Practic - Cleanliness
of Ventilation Systems
APPE DIXC
Fi e Retardant inishes C1 Improvement in the fire retardancy of plastic
ducts can be achieved to varying degrees and is wholly dependent llPOll the surface coating laminating resin selected and construction specification adopted In some instances smoke emission is coILSidered equaUy with other speci fication requirernen ts of the materials resistance to ignition and bumjng It is therefore important for design rs to establ ish the clients and officers detailed requirements and not rely on a tbird party interpretation of fire resisting or fire retardant Where possible the specification should refer dir etly to compliance with a British or European Standard identifying the specific sections applicable There are various types of resin and mat rcLnforcements that can achieve a Class 1 surface spread of flame ratin o when tested according to BS476 Part 7 (1987) This test puts materials illto Class I - 4 in descending order of perfoDllance according to the rat and extent of flame spread over their surfac under standard beating conditions Materials should also be tested for flre propagarion to BS476 Part 6 (1989) Tbi tesr measures the amount and rate of heat evolved by the material when subjected to standard heating
conditions Test results are given as an index of Perfonnance (i) whicb is based on three sub indices (iJ (i1) (h) The higher the value of the Index of Performance (i) the greater is the material s contribution to fire growth The higher the value of the sub-index 0) rhe greater the ease of ignition aod flame spread The highest product performance classification as defined in Approved Document B of the Building Regulations is Class O This is acLlieved if a material surface of a composite ploduct i~ either a) composed throughout of materials of
limited combustibility or b) a Class I material which has a tlre
propagation index (i) of not more than 12 and sub-index (i l ) of nor more than 6
01 J Class 0 is not a cla$sif1cation identified in any British Standard test
There are resin system reported to be classified to Class O when tested to BS476 Pcl1S 6 and 7 however designers need to ensure that such sysrems can be applied to their proposed design In propriety resinmat system available the fabrication techniques and COITect application are critical to the integrity of the reinforcing and clas ificatiol1 For example in some systems the u e of a non-fire retardant gelcont on a fire retardant substrate would reduce the classification For further information see HVCA publication DW144 Appendix D
55
DW154 SplCijiClIliol1 for Plastics Ductwork
x Guidance otes For nspectmiddoton Servicing a d
Clean-ng Access Openings
D1 GE ERAL This appendix highlight in ummary fOI111
the acce considerations that hould be made by the design r iD terms of inspection servicing and cleaning Having considered the seop and the design of the dUCI work system relative to the guidelines outlined below the designer should clearly indicate which levels of acces should be incorporated into the manufacture of a new duct work system (See Table 14 and Note I b low it
D2 DESIGN CONSIDERATIONS
D21 In ptction and servicing requireshyments are set out in Section 15 of Lhis specification
D22 Cleaning requirements are set out in the HVCA pubUcation TRl7 Guide to Good Practice Clean Lines of Ventilation Systems and the guide tates The precise location ize and
type of access would be dependent on the type of ductwork cleaning inspection and te ting metbods to b adopted Care protection and standards of cleanliness prior LO cOlllmisionin o
are set out in th AV A publication DWITM2 Guide to Good Practice Internal Cleanliness of New Ductwork Installations and th guide state Wh re specific limits of cleanliness are required ductwork sball be cleaned after installation by a spcialist cleaning contractor It will b in the interests of tht desioner botb financially and practically to cunsider employing a specialist c1eauing contractor at tbe
outset of a contract to internally clean newly installed ductwork prior to bandover This approach would reali e the following benefit shyi) Tb actual numb r of cleaning
access panels could be detennined to suit the method of cleaning to be adopted (This may be 1 s than the maximum requiremen listed under Lev 13 of Table 14)
ii) Clear directions could b given to the ductwork contractor as to tJle size and location of cleaning access panels that are required to be fitted during the mauushyfaclunng pro s
iii) The specialist cleaning operation prior to commi ioning vould enable the cleaning contractor to verify the practical acee requirement for the future cleaning operation associated -vitb a regular maintenance programme
iv) A specialist cleaning operation prior to commissioning would allow the designer to omit from the speeilicatiolJ the DWrrM2 requirem nt for factory sealing protection wipe downs and capping-off
v) Specialist Ieall ill 0 to the measurable standard defin d in TR17 will allow an objective definition of cleanline to be achieved
Car ful consideration must be gIven by the designer to the practl aJ problems associated witb the manufacture and fitting of suitably si Led access panel on small cross section duct and on the circular faces of rouod and flat oval ducts in particular
D23 Special con ideration must be given by the de igner to the practical problems associated with gaining personnel access to heavily congested ceiling areas and multi-la red du twork systems This approach would avoid
56
DW154 Spfciication for Plastics Ductwork
the possibility of access panels being D3 ACCESS 0 IN-LINE EQUIPMENT incorporated into a ductwork system at the This appendix unly covers acc il1spection manufacturing stage that were later found in through the ductwork body adjacent to an item practice to be inaccessible for either ervicing of in-line equipment and not openings in the or cleaning activities equipment itself
able 14 Acce requirements for inspection servicing and cleaning
HVCA PUBLICATIO REFE NeE (uidtgt 10 Gund Prartict
Adjace t OW144 Cleanliness orVcnlillltio S~lcr~ fRjJ7
in-line LeyeJ 1 Level 2 Level 3 ite sequipment pcdionSen lcin~ Section d C1eaniJl( SUn(O)lnspc lion Palle ltk~m_n
2011 (minimum OiL Jubje-ct to duct ~zel (ft~ -Panels
Control Da pcrs One (inspection) 203 One 300 mm x 200 mm Both sid Fire Dampers One (sCTjdJl~) 20211 One 300 0101 x 200 mm One side HeatingCooling Coils One (inspedion) 20213 One 300 mm x 200 mm (lIpstream) Both sides Attenuators (rectangular) None required One 300 mm x 200 mm (downstream) Both sides Attenuators (circular) one retluired One 300 mm x 200 mm (downstream) One side Filter Sections One (inspection) 20212 one required Uoth sides Air Turn Vanes None requjred None required Both sides Changes of Direction None required one required One side In-Duct FansDevices One (inspection) 20213 None required Both sides l
1 In the absence of any indication by the designer only Level ) access will be jncorporated into a new ductwork system
2 Tbe panel izes associated with Lev lis I and 3 acee s ar e middottablished by reference to Section 20 of DW144 and Section 2 ofTRll7 respectively
57
DW154 Speclfifatio for Plastics Ductwork
pA XE
B-bliography Included in this Bibliography are technical pUblications which may be of interest (0 ductwork designers fabricators and erectors and to tho e in the heating ventilatlng air conditioning industries generally nquiric should be made of the relevant organisation at the address quoted Since its publication other addresse contained within 0V154 mav have changed and some pubJicalions may have been superseded
HEATING AND VENTILATING CONTRACTORS ASSOCIATION
4 Palace Court London W2 4JG Telephone 020-7229 2488 Fax 020-7727 9268
Orders fo FlY A Publications Old Matlsion House Eamont Bridge Penrith Cumbria CA 10 2BX (Telephone 01768 864771 Fax 01768 86718) Email hvcapoblicationshvwelfarecouk DWn 44 pe ilicatiun for sheet mctal duclwork (Iow- mediulllshy
and high-pressure) 1998) DWIl4 A practical guide to dUGI ork I akage te ting
(revised 2000) DWII54 Specification for plastic~ duct rk DW171 Guide to good Practice for kitchen venlibtion system DW191 Guide to good pracuce glass fibre ductwoJk DwrrMI Acceptance cheme for new products - Redangolar cro
joint classification Guide to good pra tice - Internal cleanliness of new ductwork installations Guide to good practice for the design for the Installation of lire and smoke uampers
J 1Other puhlications
HampV safely guide 5th edition JS2 Tool box talks JS5 Weldlng Safety booklet JSI9 afety facts bo klet Fact sheets 1-24 2nd edition JS2J COSHH manual volume 1 Advice on compliance with the
regulations 1521A CO I-rH manual volume 2 Asses mcnt h ets JS23 Ri k management manual TR3 BrazinltT and bronze welding of copper pipework cUld sheet
(I 976) TR5 Welding of carbon steel pipework (1980)
TR6 Guide to Good Practice for Site Pre sure Testing of Pipework (19 0) Guide to good practice cleanliness of ventilation Ylem
CHARTERED IN TITUTlO OF BUILDING SERVICES E G EERS Delta House 222 Balham High Road London SW12 9BS rTelephone 020-8675 5211 Fax 020-8675 5449) CIBSE Guide Volume A Design Data Volume B In tallatiol1 and quipment Data Volume C Reference Data
CommlssioniJIg Codes These Codes eover the preliminary checkS eUing to work and regulation of vanous catcgories 0 plan The Codes give a guide to design implications Series A Air Distnbution Systems Series B Boiler Plant
ri s C Automatic Conlrol ystems Cr1es R Refrigerating Sy terns
Sene iN Water Distribution Systems
Technkal Memonllda TM 4 Design Notes for the Middle East TM bull Design otes for Ductwork TM 13 Minimi iog lhc Risk of egiounaires Disease
Research Reports RROI95 Ventilation system hygiene - A review of published
infomlatioo on lhe occurrence and ffects of Olltamination Rl~02J95 Air-to-air heal rec v ry RR0395 rnfluen e of HV C on smoke detectors
ATlONAL ENI [ERING SPECIFICATION LfMITED Southgatc hamber 3739 Southgate Street Winchester S023 9EH (Telephone 01962 842058 Fax 01962 R(8982) BUfLDING S RVICES RESEARCH AND [ ORMATION ASSOCIATIO Old Bracknell Lane West Bracknell Berkshire RG 12 4AH (Telephone Brackl1eU (01344) 426511 Fax 01344 487 -7 )
Application Guides AGln4 De tglJing Vana~le Volume middotylans for KOOnl
iir Movement AG1I91 Commissioning of V Sylcms in Buildings 11 6194 Fire Dampers
B) 94 cntiJalion or KitcneTls
AG389 The Commls ionin of Air Systems In Buildmgs AH2192 Commissioning of Bern - A ~ode of Practice TN2417 I Fire Dampec il) Ventilating Ducl
BEATING VENTILATING A AIR CONDITION G MA UFACTURERS ASSOCIATIO (HEVAC) HEVAC Henley Road Medmenham Marlow Buck SU 2ER (Telephone 01491 578674 ox 01491 575024 Emoimiddot infofetacouk)
Publicatjons Air Diffusion Guide Guide to Air Handling Unit Leakage Testing Guide to Good Practice Air Handling Unit Real Room Acoustic ~ st Procedure Specification for the ertiiicatioll ofAir Filters Method of Test for Water Rejection PerfOnTlatce of Louvrcs Subjected 1(1
Simulated Rainfall Test Procedure for Acoustic Loo cs Specification 10 Floor GrilJes - Types Performan e and Method ofTest Specification for the Determination of the Collection Efficiency of SilJ1d
Trap Louvre Domestic Mechwlical Vclltllalion Systems with Heal Recovery Fan Application Guid
~an and Ouctwork Installation Guide Guide to Fan Noise and Vibration
pecification of Requirements for JallJral Smoke and Heal Exhausl Ventilators
pecification for Powered Smoke and Heat Exhaust Ventilators
Specification of Requirements for Smoke Curtains Design Gujue of Smoke Ventilation for Single Storey Lodustrilll Building~
Including those with Mezzanine Floor and IIi Racked Storage Warehou es - Issue 3
Guidance for the Design of Smoke entilation YSlem for Covered and Undergrollnd Car Parks - lssue 1
Application of SOloke Control Equipment and Syst m Guid to Good Practice - Isue J
58
DW154 Sp(C~tiifitiol for Plastics Ductwork
BRITISH STANDARDS INSTIT TION Sales Department 101 P ntooviLle Road London NI 9ND (felephone 020-78 1 78801)
CP 413 1973 Ducts for building ervices
SS 476 Fire tes on building matenals and lruc(ure
Part 4 19 4 Non-combustibility lest or materials
Part 6 I Fire propagation lest for materials
Part 7 1993 Surface spread of tlarnJ tesls for materia
Part 20 1987 Fir resistance of elements of construction
Part 21 1987 Fire r sistlUlce of loadbeanng elements of construction
Part 22 1987 Fhe istallceofllon-loadbearing elemcllts ofconsttuclion Part 23 1987 Contribution of componcnts to the fire resistance 0 a
structure
Part 24t987 Fire resi lance of wl1lilation ductl
SS 5588 nan 919 0 Fire Precautions III thc desIgn and OOSlnJ lion of buildings
S 729 1971 Hot dip galvanized oatiugs (or irOIl aod stcel articles
BS 1449 Steel plate sheet and Irip
Pan 11991 Carbon steel plate heel and strip Part 2 1983 Stainless steel plate sheer and strip
and
B middotENJOI49-2 996 BSEN 10149- 1991)
BSEN 10131 1992
BSEN22063 Sprayed metal coarings 1994 Protection of iron and steel by aluminium and zinc against
atmospheric cOlosion Irotectiotl of iron and ste I against corro ion and oxishydation at elevared temperatures
BS 353 1981 Glossary of lerms relnting to thermal insulation
BS ISO 1479 Self-tapplngscrewsandmetallicdri c crew
B -lSO 7049
1994
B 4800 1989 Painl colour for building purposes B 4848 l0 rolled structural steel sections
Part4 1972 Equal and unequal angles BS 5422 1990 Specification for the use of therm illuating matcriulS
SS 5720 1979 ode of practice for mechanical veutilating and air C 11shy
dirionin bull in building
l3S PR 12814-1 Bend resting for plasric welds
SS PR 12814-2 Tensile testing for plastic welds
SS PR 13067 Appro altesting for plastic welds
BS PR EN I 100-] Vi ual in pection ofplaslic welds
SHEET METAL AND AIR CONDITIONING CONTR-CTORS NATIONAL ASSOCIATION INC (SMACNA) Headquarters 420 I Lafayeue Center Drive Chanlilly Virginia 2051-1209
Mailing Address pa Box 221230 Cbantilly Virginilt120 153-1230
Telephone (703) 803-2980 Fax (703) 803-3732
Accepted IJJdustry Pl3Gtice for Industrial Duct Constnlelion 197 ) i-rchitecmral Sheet kwl Manual ([993)
Comractors Guide lor Modification 10 ooslruerion Colllraets 1993 Ducted Eleclric Heat Guide for ir Handling Ssrerns (1994)
En~rgy ollservatioD Guidelines (1984) Energy Recovery Equipment yslClllS (199l
Fibrou GIns Duct onS1ntClion Standards (1992)
Fire Smoke amp Radiation Damper In tall Guide for HVA Syst ms (1992) Guide t leel Stack 1(95)
HVA Air Duct Leakage Test Manual (19 ) HVA COlllmissioning lvlanual (1994)
H A Duct Construction Standards-Metal amp Flexible (1995) Addendum 01 (Nov 1997)
HVA Duct Systems Inspection Guide (1989)
HVA ySlems-Application (1986) nVAC ByternS-DLlct D ign (1990)
HVi Systems-Testing Adjusting amp Balancing (1993)
indoor Air Quality Manual (1993) tcheu quipment Fabrication Guidelmes (1990)
Managers Guide for elding (1993)
Rectangular Industrial Duct Cons1TUction Standards (19 0) Round Industrial Duct oustmction Standards (1977)
Sei mic Restraint Manual (1991) (wl Appendix E 1993) SMACNA Ma le Index ()fTechnical Publications (1995) Tbennoplnstic Duct CPY ) Construction Manual 1994)
DEPARTME OF THE ENVIRO MENT (Publications Centre) H Stationery Oflice 5 Nine Elms Lane London SWS 5DR
MampEJ 011972 Electrical in tallat1011 in buildings ( ew Editiou)
IampE 0319 Healing hot and cold wat r steam and gas losla1lations for buildings
M amp - No4 1970 Central heating and hot and cold ~ ateT in tallations for
dwelling
M amp ENo100 1971 Mechanical ventilation for building~
ASSOCIATION FOR SPECIALIST FIRE PROTECTlO As ociation House 235 Ash Road AJdershot Hampshire GUl2 4DD
Telephone OJ25221322 Fax 0 J252 333901
lublicalioos Fire Ratcd and moke Outlet Ducrwork An Industry Guide t Design and InSlalla lioll
HEALTH AND SAFETY EXEC TIVE Rose Court 2 Southwark Bridge London SEl 9HS Telephone 020-7717 6000
TWJ THE WELD G TlTUTE Abington Hall Abington Cambridge CB16AL Telepbone 0 J223 89162
Publication DatJ Oil w~ldll1g of lhermopla lics
59
DW154 wciiwlioll for Plastics Ductwork
A -=--DIX
Factors
Specific gravity shy pp = 091 approx UPVC = 14 approx
Some miscellaneous conversion factors
To convert
Length Inches to millimetres Feet to metres
Multiply by
2540 03048
To convert
Millimetres to inches Metres to feet
vIultiply by
003937 3281
Area Square inches to square millimetres 6452 Square millimetres to square inches 000155 Square feet to square metres 00929 Square metres to square feet 10764
Volume Cubic feet to cubic metres Cubic feet to litres Gallons (UK) to litres
002832 2831 4546
Cubic metres to cubic feet Litres to cubic feet Litres to gallons (UK)
35315 00353
022
Mass Ounces to grams Pounds to kiJograms Tons to tonnes
2835 04536
1016
Grams to ounces Kilograms to pounds Tonnes to tons
003527 2205
09842
Volume flow Cubic feet per minute to cubic Cubic metres per second to cubic
metres per second 0000472 feet per minute 2119 Cubic feet per mIDute to litres Litres per second to cubic feet
per second 04719 per minute 2119
Motion Feet per minute to metres per second 000508 Metres per second to feet per minute 197
Pressure Inches water gauge to millibars 2491 Inches wateJ- gauge to pascals (Pa) 2491 I Pa = I ewton per square metre = 10-2 millibars
60
Heating and Ventilating Contractors Association Esca House 34 Palace Court London W2 4JG
Tel 020 7313 4900
e-mail contact Itvcaorguk web site wwwhvcaorguk
Fax 020 7727 9268
DW154 Specijicutiolt for Plastics Ductwork
FIG
68
69
70
71
STANDARD COMPONET DRAWINGS shy REC ANGULAR
DRAVING DETAILS
gtshy Access Openings
AP 6 Access Panel - Rerno able
w [ ~ Access Door - Hinged
I ~le Inspection Cover
le -I reg -lt
~X X Flexible Connection
~ Drop Cheeked Radiussed Twin Bend
U Drop Cheek Bend
I
72 Air Flow SymbolX
38
DW154 Specifim[ioll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - ECTANGULAR
FIG DRAWING DETAILS
73
74
75
76
77
Q
Q
rp---t
~
V- I Ir---I
JL --11
THE ABOVE DETAILS TYPICAL PLENUM
Air Terminal Plenums
Plenum with side connection
Plenum with top connection
Cover plate with connection
Special plenum with connection
elescopic conn ction in direction of air flow
39
DW154 SpecijicotiOll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG
78
79
80
81
DRAWING
-23~---pound3-(MALE) (FEMAJE)
-t=j--_j(--d-shy
--L
~ THROAT RADI S= D AS T NDARD
e ~
THROAT Rjf)lU = D A MU)
DETAILS
Straight Duct With male and female connectors
Straight Duct With flange joint and slip joint
Bend MouldedIFormed Applies to any angle ego 30deg45deg60deg90deg Medium radius bend as illustrated Long radius similar but throat radius 0
Segmented Bend 90deg four section minjmum as illustrated
Other Angles 60deg = 3 sections 45deg = 3 sections 30deg = 2 sections
I
i
40 shy
DW154 Speciicafinll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG DRAWING DETAlLS
82 Segmented Twin Bend Radius = D2 max
May also be fabricated from tube
83 Equal Tee MouldedIFormed
84 -~ 1in Bend MouldedIFormed
85 Taper Concentric 1 0 as iUu trated Eccentric 30deg iJJcLuded angle
86 Short Taper
41
DW154 SpcUicatol1 for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG DRAWING DETAILS
87 30 max Offset
Angle Branch
Bran h dUCI Dimcnsions dia (D) lA)
Shoe Branch mm mm 88 Cl
Off rectanguJur Up 10 200 75 lOO 10 400 125
- 00 150 Over 600 200
Bl1IllCh duct DimenlOns din (D) (A
~-$a-Conical Branch mm mm
89 Also acceptable with Up 10 200 r
full conical surface 300 10
400 125
END VrE -shy 600 150 Over 600 200
90
m 75
100 12 150 200
mm Up to 200
_ 300 400
600 Over 600
iUtred Branch
Shoe Branch
J-L----U ~ Bell oulh Branch
ENDV1EW
93
92
91
42
DW154 Specificatiol for Plastics Ductwork
STANDARD OMPONENT DRAWINGS - CIRCULAR
FIG
94
DRAW G
I
~ 30deg 090deg
Breeches Piece
DETAILS
95 amp-----~ Blank End
~-----p Multi-Leaf Damper Can be piggolcd or fianged opposed or parallel blade
Alternative controls areshyri=-+- L-T~
I
---
LT~
I r- -
-+1
J HO Hand96
bMD Molori cd
PD Pneumatic
tl-shy bull
Single Bladed Damper 97 ~ saD
on-Return Damper Vertical application only 98 m~D
43
DW154 Sf1tcificatioll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG
99
100
101
102
DRAWING
$ I-
2hr
1 4hr
SD
~v I I
CO TINENTAL COWL
DETAILS
Iris Damper
Fi reS moke Dam persSleeves
2hr Ratillg
With installation frame
4br Rating
Smoke damper
Intumescent Sleeve
Access Openings
Access panel - removable
Access door shy hinged
fnspection cover
Discharge Continental Cowl
44
DW154 Sp(Cii(ltJll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
DRAWINGltIC DETAns
-
I
I
~
I I I High Velocity Discharge Terminal 103 I
I
I I
J I I 1 ~--
Offset Stack Discbarge Terminal 104 1
~ I e --(-
I
N
I
I
I~
I I Vertical Oischarge with Weather Cowl 105 I
--1--1 I
I
GAPI I
RTl AL DISC) lARGE WITH W ATIIER COWL
45
DW154 SpecUicatoll for Plastics Ductwork
STANDARD COMPONE T DRAWINGS - PLA TEQUIPMENTIMISCELLANEOU
FIG DRAWING DETAILS
106 ~~~ Rectangular Attenuator
107 ~- Circular Attenuator
108
~ Beod Attenuator
109 J ~(f) Heating Coil
110 J ftte Cooling Coil
III Jc[ Electric Heating Coil
112 X F
Humidifier
113 [H XX Axial Fan
114 ~fB1famp Noo-standard Ductwork Cross hntchillg (of any separate type) indicates by reference to a key any non DVil54 ductwork system
115 2llIIIIJIIIIIll Flexible Ductwork
46
DW154 SJeCUicll(iol1 for Plastics Ductwork
TABLE 12 - STANDARD ABBREVIAT ONS
ABBREVIATION FLL
AD Acces Door
AFF Axial Flow Fan
AHU Air Handling nit
All Aluminium
AP Acess Panel
AT Attenuator
AV Air enninal Unit
BE 81ank nd
BQ Blast ate Damper
CC Cooling Coil
CF Centrifugal Fan
CTA Cross alk Attenuator
CVU Constant Volume Unit
DP Drain Point
EEC Electric Heating Coil
El Expansion Joint
FAl Fresh Air Inlet
FA From Above
FB From Belo
fBPP Fabric Backed Polypropyl-ne Sheet
Flexle Flexible Connection
lexfD Flexible Du t
C False Ceiling CO an oil Unit
fD Fire Damper
FFL Finished Floor Level
FJ Flanged Joint
FOAM Rigid Polyurethane Self xtinguishing Foam
FOB Flat on Bottom
FOT Flat on Top
GAM Galvanised after ManufacttrJc
GRP Glass Reinforced Plastic
GSS Galvanised Sheet Steel
HC Heating oil
HD and controlled Damper
HH Hand Hole
HL High Level
HVD High Velocity Discharge
IC Inspection Cover
ID lri Damper
IFS Intumescent Fircleevc
47
DW154 Specification for Plastics Ductwork
TABLE 12 - STANDAR ABBREVIATION CONTINUED
ABBREVIATION
IU
L
tv1D
MS
NRD NTS
OBO
OE
PHD
PD
PP
PP
PRD
PVC
RFC
RSC
R
SBO
SO
S1 TST
SSL
TA
TB
TO TJ
TP
TV
TV
OS
UPVC
S
V
VAV
50 RSA
FULL
Induction Unit
Low Level
Motor controlled Damper
Mjld Steel
on Return Damper
at to cale
Opposed Blade Damper
Open End
Parallel Blade Damper
Pneumatic controlled Damper
Polypropylene
Self xtinguishing Polypropylene
Pressure Relief Damper
Polyvinyl Chloride
Rolled Form Chamlel
Rolled Steel Channel
R fUnit
Singl Blade Damper
Smoke Damper
Slip Joint
Stainl t el
tructural Slab Level
To Ab vc
To Blow
Top Down (In Direction of Flow)
Telescopic Joint
Test Point
TU111iog Vane
Top Up (In Direction of Flo )
Voles Otherwise Stated
Unpl3sticisecl Polyvinyl Chloride
Underside
Ultra Violet Light
Variable Air Volume
Rolled Steel Angle (Vith Size)
48
DW154 SJeriiflllioll for Plastics Ductwork
A2 DUCT PRESSUREAPPE DXA Ductwork con truct d to DWIl54 will bebullbullbullbullbullbullbullbullbullbullbullbullbullbull
Air Leakage From Ductwork To be read in conjunction with DW143 A practical guide to Ductwork Leakage Testing
CAUTION As highlighted ill both this docul1lenr and DW14 I lot ellough emphasis can be placed 01 the fact that except for high pressure class C the much more stringent ductwork constructional standard brolght about b the general acceptance of DW154 have irtlally negated the requirement for leakage-testing It is essential lO realise lhat except where it is mandatory this doclllllelll is nOl an endors ~lIlent of the rourine testing of ducts bllt purely a guide to outline the procedures for cononnity with the air leakage limits ill Table l Where the specified methods of assembly and
A3sealing of dlcls are u ed a vi ual inspection wil ordinarily sl~fll e for ver(iatioll of a well engineered and a ceptahfy airtight COl1strucrioll WHERE NOT MANDATORY DUCT LEAKAGE TESTING IS GENERALLY AN UNJUSTIFIED AND SUBSTANTIAL EXPENSE
A1 INTRODUCTION L akage from ducted air distribution systems is an Lmportant consideration in the design and operation of ventilatjon and air conditioning middotystems A ductviork t)ystem tbat ba limited air leakag within defiucd limits wiH cnsUft
that tile design characteristics of the sytem can be maintained It wilJ also ensure that energy and operatLonal cosb are maintained at optimum levels DucLwork constlucted and Ulstalled in accordance with DW154 should minimise a level of air leakage that it) appropriate to tll operating static air pre sur in tile system
A4However it is recouuised that tbe environment in wtJich middotystems are installed is not always conducive to achieving a predictable level of quality in term of system ajr leakage and it is therefore accepted that designer may sometimes require tlle ystem to be tested in part or in total It should be ecogni ed that the testing of duct systems add a ignificant cost to the installation and incur some extra tjm within the programme (Se 47 and 64 re mandatory te-sting)
manufactured to a structural standard that is compatible with the system operating pressure There are three classes of duct con truction to eorre pond with the three pre ure clas meations Class A Lo pressure ducts suita le for a maximum positive operating pressure of 500 Pascal and a maximum negative pressure of -500 Pascals Class B IVledium pressure ductmiddot suitable for a rnaxilnuJJl positive operafjn o pressure of 1000 Pascals and a maxllnum negative pre sure of -750 Pa cal Class C High pre sure ducts suitable for a maximum po ilive operating pressur of 2000 Pa cals and a maximum negativ pres ur of -750 Paltcals
LEAKAGE FROM DUCTWORK Leakao-e front pia tic air ducts occur at the joint~ and is therefore proportional to the total surface area orthe du twork in th system Tb level of leakage i imilarly related to tIle air pres ure in th du t system and whilst there LS n precis formula for calculating the level of air los it i generally accepted that leakage will increase in proportjon to pressure to rbe pOvver of 065 The effect of air leakage from high pressure velocit ductwork is critical tn terms of system perfomlan dege energy consumption and the risk of high frequency noise as ociated with leakage These problems are le critical with medium pressure 10 ity systems but should be con idered Low pres mevelocity ducts present the lowe~t
ri k in tenn of tbe effect of leakage on the operation of the s stern
SYSTEM LEAKAGE LOSS As there i no di ct relatLonship between th volume of air conv yed and the surface area f the ductwork sy tern required to match the building configuratmn it is difficult to express air leakage a a percentage of total air volume Similarly the operating pressure will vary throughollt lh 3 system and a leakage is related to pre me the calculations ar comple However it is generally ac epted tbat in typical good quaJjty systems the leakage from
49
DW154 Specificatioll for Plastics Ductwork
each class of duct llnd r operating condition will be io the region of CIa S A low pressure 6 Clas B medium pres un 3 Clas C high pressure 2
A5 SPECIFYING AIR LEAKAGE TESTING Re peeting both the co -t and programme implications a sociated with te ling du 1 for leakage the designer may for example indicate that a particular system is te ted as follow
a) High pressure ducts - all tested b) Medium pr ssure duets - 10 of the
ductwork shall be s eet d at random and tested
c) Low pre sure - unte ed In any case where a random te t i elected for medium pre sure ductmiddot the followin c1au~e is suggested for inclusion by the de ign r
The designer hall elect at random a maxirnwlI of 10 of the dUCl system to bt tested for air leakage The duct hall be tested af the pressure recommended in Table J3 for the assifi atiol for the ectiol1 of the ductwork that is to be tested The tests shall be carried Ollt as the work proceeds and prior to the application of thermal insulation In the event of test failure of the randomlY selected section the designer shall have The right to select two La1her e tiolls at random for resting Where succes ive failures are identified there shall be a Tight to require rhl COl11raCWr 10 apply remedial attention to the complete ductwork system Th contractor shall provide documented eviden e of the calculalions used to arrive (1
the allowable 10 I for the section to be tested and the client or his agent shall willess and sign the results of the test
able 13 Air leakage rates
Maximum leakage of duct work Static
prcssUft Low-pressure edium-prc-sure I Iigh-prebull me diJfercntial Class A Class B Class C
1 2 J 4 Pa Litres per second per quare metre of surface area 100 054 018 ZOO 084 028 300 110 037 400 132 044 500 153 051 600 058 019 700 064 021 800 069 023 900 075 025
1000 080 027 1100 1200 1300 1400 1500
029 030 032 033 035
1600 1700 1800 1900 2000
036 038 039 040 042
Note Recommend d mean test presures are highlighted iD bold type with the actual selection being left to tll test operator
50
DW154 Sfeeiieaioll for Plastics Ductwork
A9
A10
and air leakage classification for the y em under test
DESIGNERS CALCULATIONS The designer can middotaJculate with reasonable accuracy the predicted total loss from a ystem by
a) Calculating the operatin presure in each ection of the sy tern
b) Calculating the surface area of the ductwork in each correspondin pre lire s ction
c) Calulating the allowabl~ los at the operating pressure for each ection of the system (see table 13 for allowable leakage figures)
VARIABLE PRESSUR S IN SYSTEMS De igner can achieve significant co t saving by matchina operating pressures throughout the system to constmctional standard and appropriate air leakage testing eO the practice of specifying construction tandards for whole duct sy tems based on fan discharge pre sure may incur unnece sary costs on a project For example ome large sy terns ould well be classiC ed for I akage limits as follows
Plant room risers CJas C Main floor distriblltJou CIa B Low pre sure outlets Cla A
A6 SPECIAL CASES There may be ~itLlations on a project where circumstance dictate thal pecial consideration be given to containing air loss s eg a long mn of duclwork may incur a di -proportjonate level of air 10 s In ca es such as thi example the designer can specify an improved tandard of airtighmess ie 80 of alJo~able 10 s for la B Ju ts The designer sbould not specif a CIa C t sI at CIa s C pressure for a CIa s B ducl
A7 SUGG S ED RANGE OF TES ING
A8 TESTING OF PLANT ITEMS Items of inline pJant (eg Fig 106 to 115) will not normaUy be included in an air I akage test The dllctwork contractor may indud such itelllS in tbe te t jf rh quipm ot has a certificate of COnfOlnlity for Ihe pres ure clas
bull High pressure duct bull Medium pre sure ducts bull Low pre sur ducts bull Exposed extract syst ID bull Ceiling void extract
systems bull Secondary ducts from
VAV or fan coil units bull Flexjble duct bull Final connections and
branches to grille and diffusers
100 test See A5 Untested UDt sted
Untested
Untested Untested
Untested
SI
i
DW154 SJecijicafion for Plastics Ductwork
ig 116 Permitted leakage at various pressures
Leakage in litres per second per square metre duct surface area
Vgt
o ltgt 0 ltgt N
ltgt Cgt
0 0 cc
0 0
~
g =
g ~
c 0
J
ltgt 0 I
~ ] tn
ltgt ltgt
In ol
~ 0 ~ 8 ~
~
c ltgt ltgt
~ CJ
~ ~ ~ ~ 8
0shyij
~ ~ ~ t
ltgt ltgt 00
l
~
~ Q
c C
~ rshy
e ltgt
I 1
I Cgt ltgtv
c Co ~
~~ ~ 10
I
0 Cgt
fJshyq 410 ) 1 ltgt
ltgt N
~ shy ltgt ltgt
~ I 1
c
52
DW154 Specificatio for Plastics Ductwork
Example of a completed test sheet Test No
General
Name of job N~ jC43Pt(r2lef Building Repound ~(~~0
Part 1 - Physical details
a Section of duct work to be tested ~(diffPIfff~el1f3rd Floor
b Drawing Number g91~~ c ssure aSSJ L atlOn V~Jl~IRfYgtg~~lPre Cl T Class C
d Test static pressure -(9 raErq~ ~~~~-~~J~~~ ~~ ~~~~ll
Leakaoe factor 9~-tre3$ecMz I OM REFTOTABLE 13)e b bullbullbullbullbullbullbull
f Surface area of duct under test Q~tJJItetre$ CPROMCALCU TIO BELOW)bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull ampampamp bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull
g ]Vlaxi mum permitted leakage -~ (~i~~0 ~~r~~ ~~~l-~-11~ ~~~Q
Part 2 - Test particulars
a Duct static pressure reading 9QFt~q~ ~ middot~~~1 ~~
b Manufacturer and type of liow measuring d vice (-~~~cJ~Y-9Q7EYg c Range of measurement of now measuring device QtP)OQ~(e~~~0I~~~~1~I~ ~~~~~~W~
d Reading of flm measurin o device pmiddot IFROM RIO)ftscag ~
I (DERlVED [ROM CHART SUPPUED WITH RIG US 0 ud)1e Interpreted air flow leakage rate ~(~~~f~~~ (~l~~~~~~~~~~~~~~~~~I
f Duration ~~~~~norn~allY l~ lnil1Ut~~d~~~ it1~ W~ Date of test ~(lITled ut by Wltll s ed by ~ ~
(~lJ MIJLrr) (Si~rrfltJUYJ
Printed Name 1~g0f~ Printed Name ~~Y~9~ and Company 7jl~~~~~( UJd CompanY AB COII$Itallt8
Width and depth or diameter
Periphery ength Area
millimetreS millimetres metre qL1are metre
800 x 750 3100 1755 5440
600 x 650 2500 557 1193
300 x 300 1200 120 144
305 din 958 700 670
250 dia 785 450 353
TOTAL 8000
53
DW154 Specijilarion for Plastics Ductwork
pA XB
Guida ce No es For he ransport Handling and
Storage of uctwork
avoid damage to adjacent duct panels In somc ca es particularly on con acts calling f r repetitive sizes the use of timber jigs and spacers may be justified Where reduced bulk and greater protection are major factor such as consignments for export transporting ductwork in L shape sections may justify the increa ed ite as embly co ts
It is recommended that before a contract is finalised that consideration is given to the subject of site acces material handling and storage as tbcy havgt a strong influence on the cost efficiency of the overall activity of ductwOlk installation
B3 Handling To minilnise th risk of damage duct sections should be clearly identified and deliveries to site should be closely linked to the installation programme so as to avoid accumulation of
B1 Storage and Handling of Ra Material Material should be stored in suitably designed racking out of direct unJight Where possible the e racks should be metal to earth Edges of cut she t may be harp and protective gloves are advised Wearing teel toe-capped boots is recommended Most pIa tic sheet is manufactured with smootb mfaces andor is suppLied with protective coating Care must be taken to prevent accidental lippag of stacked materials Beiuoshy good electrical insulators the movement of stock unless earthed will allow the build up of stati All stock shapes are chemically stable at normal temperature Whil t some raw materials used in their manufacture may themselves pre ent a toxic hazard once incorporated into the lOck bape they no long r constitute such a hazard and no dermatitic bazard are known nor are any
unfiJied ductwork and minimise double handling It is important to recognise that ductwork panels joint and corners arc susceptible to damage and care must be taken wheu band ling such material through a site During handling individual item of duct work may be liable to light cross sectional deformation until thev become an integral pan of a completed ductwork system Whilst this may temporarily detract from its intended appearance thi deformation will not have any detrimental effect on the functionality of the finally a semblecl system Installation of duct work and asociated plant items ill illevitably involve manual handUng The responsibi Iiry of employers and employees to a ses the risk of personal injury during mallual handling operations is et out in the HS E publication L23 Guidance on Manual Handling Regulations 1992
environmental problems expected 84 Site storage
B2 fransport Large capacity vehicles with high-sided open or closed-top bodies are tlle mo t suitable for the transport of dllctwork Careful consideration should be given to the
Adequate floor space IDust be provided within tbe building for the site storage of ductvork Such storage shalt make due allowance for thc stOf(ne of ductwork in stacks such that access ~ egt
between them is of sufficient width to pennil the removal of item without interference to
unloading of transport on sit a not all siJes b n fit from the material handlino- and access facilities that exi [ in a manufacturing workshop such as crane- fork-lifts or loading bay Site handJiog facilities along with
adjoining sta ks Ductvork components should be positioned so a to avoid crushing Ductwork of small panel size may be stored horizontally however care should be exercised to ensure that tack sizes are limited 10 within
ehicular acce s restrictions may itilluence the type and ize of transport to be uWised
engtlls of ductwork should be positioned 0
the tmctural strength of the duct sections to prevent distortion of the lower sections within the stack
as to avoid crushing Lengths Witll projections such as branches and bends i1anges girths damper quadrauL should be loaded so as to
54
DW154 S1tciic(ltioll for Plastics Ductwork
85 Internal cleanliness of new ductwork The site storage of ductwork introduces the important cODsideration of maintaining the internal cleanliness of the ductwork R feren e should be made to HVCA documentshybull DWffM2 Guide to Good Practice - internal
Cleanliness of New Ductwork Installations If the above conditioDs can not be satisfied consideration should be given by tJle designer to amending the specification to include for Po t Installation Cleaning as covered by tJ1C HVCA documentshybull TRJ17 Guide to Good Practic - Cleanliness
of Ventilation Systems
APPE DIXC
Fi e Retardant inishes C1 Improvement in the fire retardancy of plastic
ducts can be achieved to varying degrees and is wholly dependent llPOll the surface coating laminating resin selected and construction specification adopted In some instances smoke emission is coILSidered equaUy with other speci fication requirernen ts of the materials resistance to ignition and bumjng It is therefore important for design rs to establ ish the clients and officers detailed requirements and not rely on a tbird party interpretation of fire resisting or fire retardant Where possible the specification should refer dir etly to compliance with a British or European Standard identifying the specific sections applicable There are various types of resin and mat rcLnforcements that can achieve a Class 1 surface spread of flame ratin o when tested according to BS476 Part 7 (1987) This test puts materials illto Class I - 4 in descending order of perfoDllance according to the rat and extent of flame spread over their surfac under standard beating conditions Materials should also be tested for flre propagarion to BS476 Part 6 (1989) Tbi tesr measures the amount and rate of heat evolved by the material when subjected to standard heating
conditions Test results are given as an index of Perfonnance (i) whicb is based on three sub indices (iJ (i1) (h) The higher the value of the Index of Performance (i) the greater is the material s contribution to fire growth The higher the value of the sub-index 0) rhe greater the ease of ignition aod flame spread The highest product performance classification as defined in Approved Document B of the Building Regulations is Class O This is acLlieved if a material surface of a composite ploduct i~ either a) composed throughout of materials of
limited combustibility or b) a Class I material which has a tlre
propagation index (i) of not more than 12 and sub-index (i l ) of nor more than 6
01 J Class 0 is not a cla$sif1cation identified in any British Standard test
There are resin system reported to be classified to Class O when tested to BS476 Pcl1S 6 and 7 however designers need to ensure that such sysrems can be applied to their proposed design In propriety resinmat system available the fabrication techniques and COITect application are critical to the integrity of the reinforcing and clas ificatiol1 For example in some systems the u e of a non-fire retardant gelcont on a fire retardant substrate would reduce the classification For further information see HVCA publication DW144 Appendix D
55
DW154 SplCijiClIliol1 for Plastics Ductwork
x Guidance otes For nspectmiddoton Servicing a d
Clean-ng Access Openings
D1 GE ERAL This appendix highlight in ummary fOI111
the acce considerations that hould be made by the design r iD terms of inspection servicing and cleaning Having considered the seop and the design of the dUCI work system relative to the guidelines outlined below the designer should clearly indicate which levels of acces should be incorporated into the manufacture of a new duct work system (See Table 14 and Note I b low it
D2 DESIGN CONSIDERATIONS
D21 In ptction and servicing requireshyments are set out in Section 15 of Lhis specification
D22 Cleaning requirements are set out in the HVCA pubUcation TRl7 Guide to Good Practice Clean Lines of Ventilation Systems and the guide tates The precise location ize and
type of access would be dependent on the type of ductwork cleaning inspection and te ting metbods to b adopted Care protection and standards of cleanliness prior LO cOlllmisionin o
are set out in th AV A publication DWITM2 Guide to Good Practice Internal Cleanliness of New Ductwork Installations and th guide state Wh re specific limits of cleanliness are required ductwork sball be cleaned after installation by a spcialist cleaning contractor It will b in the interests of tht desioner botb financially and practically to cunsider employing a specialist c1eauing contractor at tbe
outset of a contract to internally clean newly installed ductwork prior to bandover This approach would reali e the following benefit shyi) Tb actual numb r of cleaning
access panels could be detennined to suit the method of cleaning to be adopted (This may be 1 s than the maximum requiremen listed under Lev 13 of Table 14)
ii) Clear directions could b given to the ductwork contractor as to tJle size and location of cleaning access panels that are required to be fitted during the mauushyfaclunng pro s
iii) The specialist cleaning operation prior to commi ioning vould enable the cleaning contractor to verify the practical acee requirement for the future cleaning operation associated -vitb a regular maintenance programme
iv) A specialist cleaning operation prior to commissioning would allow the designer to omit from the speeilicatiolJ the DWrrM2 requirem nt for factory sealing protection wipe downs and capping-off
v) Specialist Ieall ill 0 to the measurable standard defin d in TR17 will allow an objective definition of cleanline to be achieved
Car ful consideration must be gIven by the designer to the practl aJ problems associated witb the manufacture and fitting of suitably si Led access panel on small cross section duct and on the circular faces of rouod and flat oval ducts in particular
D23 Special con ideration must be given by the de igner to the practical problems associated with gaining personnel access to heavily congested ceiling areas and multi-la red du twork systems This approach would avoid
56
DW154 Spfciication for Plastics Ductwork
the possibility of access panels being D3 ACCESS 0 IN-LINE EQUIPMENT incorporated into a ductwork system at the This appendix unly covers acc il1spection manufacturing stage that were later found in through the ductwork body adjacent to an item practice to be inaccessible for either ervicing of in-line equipment and not openings in the or cleaning activities equipment itself
able 14 Acce requirements for inspection servicing and cleaning
HVCA PUBLICATIO REFE NeE (uidtgt 10 Gund Prartict
Adjace t OW144 Cleanliness orVcnlillltio S~lcr~ fRjJ7
in-line LeyeJ 1 Level 2 Level 3 ite sequipment pcdionSen lcin~ Section d C1eaniJl( SUn(O)lnspc lion Palle ltk~m_n
2011 (minimum OiL Jubje-ct to duct ~zel (ft~ -Panels
Control Da pcrs One (inspection) 203 One 300 mm x 200 mm Both sid Fire Dampers One (sCTjdJl~) 20211 One 300 0101 x 200 mm One side HeatingCooling Coils One (inspedion) 20213 One 300 mm x 200 mm (lIpstream) Both sides Attenuators (rectangular) None required One 300 mm x 200 mm (downstream) Both sides Attenuators (circular) one retluired One 300 mm x 200 mm (downstream) One side Filter Sections One (inspection) 20212 one required Uoth sides Air Turn Vanes None requjred None required Both sides Changes of Direction None required one required One side In-Duct FansDevices One (inspection) 20213 None required Both sides l
1 In the absence of any indication by the designer only Level ) access will be jncorporated into a new ductwork system
2 Tbe panel izes associated with Lev lis I and 3 acee s ar e middottablished by reference to Section 20 of DW144 and Section 2 ofTRll7 respectively
57
DW154 Speclfifatio for Plastics Ductwork
pA XE
B-bliography Included in this Bibliography are technical pUblications which may be of interest (0 ductwork designers fabricators and erectors and to tho e in the heating ventilatlng air conditioning industries generally nquiric should be made of the relevant organisation at the address quoted Since its publication other addresse contained within 0V154 mav have changed and some pubJicalions may have been superseded
HEATING AND VENTILATING CONTRACTORS ASSOCIATION
4 Palace Court London W2 4JG Telephone 020-7229 2488 Fax 020-7727 9268
Orders fo FlY A Publications Old Matlsion House Eamont Bridge Penrith Cumbria CA 10 2BX (Telephone 01768 864771 Fax 01768 86718) Email hvcapoblicationshvwelfarecouk DWn 44 pe ilicatiun for sheet mctal duclwork (Iow- mediulllshy
and high-pressure) 1998) DWIl4 A practical guide to dUGI ork I akage te ting
(revised 2000) DWII54 Specification for plastic~ duct rk DW171 Guide to good Practice for kitchen venlibtion system DW191 Guide to good pracuce glass fibre ductwoJk DwrrMI Acceptance cheme for new products - Redangolar cro
joint classification Guide to good pra tice - Internal cleanliness of new ductwork installations Guide to good practice for the design for the Installation of lire and smoke uampers
J 1Other puhlications
HampV safely guide 5th edition JS2 Tool box talks JS5 Weldlng Safety booklet JSI9 afety facts bo klet Fact sheets 1-24 2nd edition JS2J COSHH manual volume 1 Advice on compliance with the
regulations 1521A CO I-rH manual volume 2 Asses mcnt h ets JS23 Ri k management manual TR3 BrazinltT and bronze welding of copper pipework cUld sheet
(I 976) TR5 Welding of carbon steel pipework (1980)
TR6 Guide to Good Practice for Site Pre sure Testing of Pipework (19 0) Guide to good practice cleanliness of ventilation Ylem
CHARTERED IN TITUTlO OF BUILDING SERVICES E G EERS Delta House 222 Balham High Road London SW12 9BS rTelephone 020-8675 5211 Fax 020-8675 5449) CIBSE Guide Volume A Design Data Volume B In tallatiol1 and quipment Data Volume C Reference Data
CommlssioniJIg Codes These Codes eover the preliminary checkS eUing to work and regulation of vanous catcgories 0 plan The Codes give a guide to design implications Series A Air Distnbution Systems Series B Boiler Plant
ri s C Automatic Conlrol ystems Cr1es R Refrigerating Sy terns
Sene iN Water Distribution Systems
Technkal Memonllda TM 4 Design Notes for the Middle East TM bull Design otes for Ductwork TM 13 Minimi iog lhc Risk of egiounaires Disease
Research Reports RROI95 Ventilation system hygiene - A review of published
infomlatioo on lhe occurrence and ffects of Olltamination Rl~02J95 Air-to-air heal rec v ry RR0395 rnfluen e of HV C on smoke detectors
ATlONAL ENI [ERING SPECIFICATION LfMITED Southgatc hamber 3739 Southgate Street Winchester S023 9EH (Telephone 01962 842058 Fax 01962 R(8982) BUfLDING S RVICES RESEARCH AND [ ORMATION ASSOCIATIO Old Bracknell Lane West Bracknell Berkshire RG 12 4AH (Telephone Brackl1eU (01344) 426511 Fax 01344 487 -7 )
Application Guides AGln4 De tglJing Vana~le Volume middotylans for KOOnl
iir Movement AG1I91 Commissioning of V Sylcms in Buildings 11 6194 Fire Dampers
B) 94 cntiJalion or KitcneTls
AG389 The Commls ionin of Air Systems In Buildmgs AH2192 Commissioning of Bern - A ~ode of Practice TN2417 I Fire Dampec il) Ventilating Ducl
BEATING VENTILATING A AIR CONDITION G MA UFACTURERS ASSOCIATIO (HEVAC) HEVAC Henley Road Medmenham Marlow Buck SU 2ER (Telephone 01491 578674 ox 01491 575024 Emoimiddot infofetacouk)
Publicatjons Air Diffusion Guide Guide to Air Handling Unit Leakage Testing Guide to Good Practice Air Handling Unit Real Room Acoustic ~ st Procedure Specification for the ertiiicatioll ofAir Filters Method of Test for Water Rejection PerfOnTlatce of Louvrcs Subjected 1(1
Simulated Rainfall Test Procedure for Acoustic Loo cs Specification 10 Floor GrilJes - Types Performan e and Method ofTest Specification for the Determination of the Collection Efficiency of SilJ1d
Trap Louvre Domestic Mechwlical Vclltllalion Systems with Heal Recovery Fan Application Guid
~an and Ouctwork Installation Guide Guide to Fan Noise and Vibration
pecification of Requirements for JallJral Smoke and Heal Exhausl Ventilators
pecification for Powered Smoke and Heat Exhaust Ventilators
Specification of Requirements for Smoke Curtains Design Gujue of Smoke Ventilation for Single Storey Lodustrilll Building~
Including those with Mezzanine Floor and IIi Racked Storage Warehou es - Issue 3
Guidance for the Design of Smoke entilation YSlem for Covered and Undergrollnd Car Parks - lssue 1
Application of SOloke Control Equipment and Syst m Guid to Good Practice - Isue J
58
DW154 Sp(C~tiifitiol for Plastics Ductwork
BRITISH STANDARDS INSTIT TION Sales Department 101 P ntooviLle Road London NI 9ND (felephone 020-78 1 78801)
CP 413 1973 Ducts for building ervices
SS 476 Fire tes on building matenals and lruc(ure
Part 4 19 4 Non-combustibility lest or materials
Part 6 I Fire propagation lest for materials
Part 7 1993 Surface spread of tlarnJ tesls for materia
Part 20 1987 Fir resistance of elements of construction
Part 21 1987 Fire r sistlUlce of loadbeanng elements of construction
Part 22 1987 Fhe istallceofllon-loadbearing elemcllts ofconsttuclion Part 23 1987 Contribution of componcnts to the fire resistance 0 a
structure
Part 24t987 Fire resi lance of wl1lilation ductl
SS 5588 nan 919 0 Fire Precautions III thc desIgn and OOSlnJ lion of buildings
S 729 1971 Hot dip galvanized oatiugs (or irOIl aod stcel articles
BS 1449 Steel plate sheet and Irip
Pan 11991 Carbon steel plate heel and strip Part 2 1983 Stainless steel plate sheer and strip
and
B middotENJOI49-2 996 BSEN 10149- 1991)
BSEN 10131 1992
BSEN22063 Sprayed metal coarings 1994 Protection of iron and steel by aluminium and zinc against
atmospheric cOlosion Irotectiotl of iron and ste I against corro ion and oxishydation at elevared temperatures
BS 353 1981 Glossary of lerms relnting to thermal insulation
BS ISO 1479 Self-tapplngscrewsandmetallicdri c crew
B -lSO 7049
1994
B 4800 1989 Painl colour for building purposes B 4848 l0 rolled structural steel sections
Part4 1972 Equal and unequal angles BS 5422 1990 Specification for the use of therm illuating matcriulS
SS 5720 1979 ode of practice for mechanical veutilating and air C 11shy
dirionin bull in building
l3S PR 12814-1 Bend resting for plasric welds
SS PR 12814-2 Tensile testing for plastic welds
SS PR 13067 Appro altesting for plastic welds
BS PR EN I 100-] Vi ual in pection ofplaslic welds
SHEET METAL AND AIR CONDITIONING CONTR-CTORS NATIONAL ASSOCIATION INC (SMACNA) Headquarters 420 I Lafayeue Center Drive Chanlilly Virginia 2051-1209
Mailing Address pa Box 221230 Cbantilly Virginilt120 153-1230
Telephone (703) 803-2980 Fax (703) 803-3732
Accepted IJJdustry Pl3Gtice for Industrial Duct Constnlelion 197 ) i-rchitecmral Sheet kwl Manual ([993)
Comractors Guide lor Modification 10 ooslruerion Colllraets 1993 Ducted Eleclric Heat Guide for ir Handling Ssrerns (1994)
En~rgy ollservatioD Guidelines (1984) Energy Recovery Equipment yslClllS (199l
Fibrou GIns Duct onS1ntClion Standards (1992)
Fire Smoke amp Radiation Damper In tall Guide for HVA Syst ms (1992) Guide t leel Stack 1(95)
HVA Air Duct Leakage Test Manual (19 ) HVA COlllmissioning lvlanual (1994)
H A Duct Construction Standards-Metal amp Flexible (1995) Addendum 01 (Nov 1997)
HVA Duct Systems Inspection Guide (1989)
HVA ySlems-Application (1986) nVAC ByternS-DLlct D ign (1990)
HVi Systems-Testing Adjusting amp Balancing (1993)
indoor Air Quality Manual (1993) tcheu quipment Fabrication Guidelmes (1990)
Managers Guide for elding (1993)
Rectangular Industrial Duct Cons1TUction Standards (19 0) Round Industrial Duct oustmction Standards (1977)
Sei mic Restraint Manual (1991) (wl Appendix E 1993) SMACNA Ma le Index ()fTechnical Publications (1995) Tbennoplnstic Duct CPY ) Construction Manual 1994)
DEPARTME OF THE ENVIRO MENT (Publications Centre) H Stationery Oflice 5 Nine Elms Lane London SWS 5DR
MampEJ 011972 Electrical in tallat1011 in buildings ( ew Editiou)
IampE 0319 Healing hot and cold wat r steam and gas losla1lations for buildings
M amp - No4 1970 Central heating and hot and cold ~ ateT in tallations for
dwelling
M amp ENo100 1971 Mechanical ventilation for building~
ASSOCIATION FOR SPECIALIST FIRE PROTECTlO As ociation House 235 Ash Road AJdershot Hampshire GUl2 4DD
Telephone OJ25221322 Fax 0 J252 333901
lublicalioos Fire Ratcd and moke Outlet Ducrwork An Industry Guide t Design and InSlalla lioll
HEALTH AND SAFETY EXEC TIVE Rose Court 2 Southwark Bridge London SEl 9HS Telephone 020-7717 6000
TWJ THE WELD G TlTUTE Abington Hall Abington Cambridge CB16AL Telepbone 0 J223 89162
Publication DatJ Oil w~ldll1g of lhermopla lics
59
DW154 wciiwlioll for Plastics Ductwork
A -=--DIX
Factors
Specific gravity shy pp = 091 approx UPVC = 14 approx
Some miscellaneous conversion factors
To convert
Length Inches to millimetres Feet to metres
Multiply by
2540 03048
To convert
Millimetres to inches Metres to feet
vIultiply by
003937 3281
Area Square inches to square millimetres 6452 Square millimetres to square inches 000155 Square feet to square metres 00929 Square metres to square feet 10764
Volume Cubic feet to cubic metres Cubic feet to litres Gallons (UK) to litres
002832 2831 4546
Cubic metres to cubic feet Litres to cubic feet Litres to gallons (UK)
35315 00353
022
Mass Ounces to grams Pounds to kiJograms Tons to tonnes
2835 04536
1016
Grams to ounces Kilograms to pounds Tonnes to tons
003527 2205
09842
Volume flow Cubic feet per minute to cubic Cubic metres per second to cubic
metres per second 0000472 feet per minute 2119 Cubic feet per mIDute to litres Litres per second to cubic feet
per second 04719 per minute 2119
Motion Feet per minute to metres per second 000508 Metres per second to feet per minute 197
Pressure Inches water gauge to millibars 2491 Inches wateJ- gauge to pascals (Pa) 2491 I Pa = I ewton per square metre = 10-2 millibars
60
Heating and Ventilating Contractors Association Esca House 34 Palace Court London W2 4JG
Tel 020 7313 4900
e-mail contact Itvcaorguk web site wwwhvcaorguk
Fax 020 7727 9268
DW154 Specifim[ioll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - ECTANGULAR
FIG DRAWING DETAILS
73
74
75
76
77
Q
Q
rp---t
~
V- I Ir---I
JL --11
THE ABOVE DETAILS TYPICAL PLENUM
Air Terminal Plenums
Plenum with side connection
Plenum with top connection
Cover plate with connection
Special plenum with connection
elescopic conn ction in direction of air flow
39
DW154 SpecijicotiOll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG
78
79
80
81
DRAWING
-23~---pound3-(MALE) (FEMAJE)
-t=j--_j(--d-shy
--L
~ THROAT RADI S= D AS T NDARD
e ~
THROAT Rjf)lU = D A MU)
DETAILS
Straight Duct With male and female connectors
Straight Duct With flange joint and slip joint
Bend MouldedIFormed Applies to any angle ego 30deg45deg60deg90deg Medium radius bend as illustrated Long radius similar but throat radius 0
Segmented Bend 90deg four section minjmum as illustrated
Other Angles 60deg = 3 sections 45deg = 3 sections 30deg = 2 sections
I
i
40 shy
DW154 Speciicafinll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG DRAWING DETAlLS
82 Segmented Twin Bend Radius = D2 max
May also be fabricated from tube
83 Equal Tee MouldedIFormed
84 -~ 1in Bend MouldedIFormed
85 Taper Concentric 1 0 as iUu trated Eccentric 30deg iJJcLuded angle
86 Short Taper
41
DW154 SpcUicatol1 for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG DRAWING DETAILS
87 30 max Offset
Angle Branch
Bran h dUCI Dimcnsions dia (D) lA)
Shoe Branch mm mm 88 Cl
Off rectanguJur Up 10 200 75 lOO 10 400 125
- 00 150 Over 600 200
Bl1IllCh duct DimenlOns din (D) (A
~-$a-Conical Branch mm mm
89 Also acceptable with Up 10 200 r
full conical surface 300 10
400 125
END VrE -shy 600 150 Over 600 200
90
m 75
100 12 150 200
mm Up to 200
_ 300 400
600 Over 600
iUtred Branch
Shoe Branch
J-L----U ~ Bell oulh Branch
ENDV1EW
93
92
91
42
DW154 Specificatiol for Plastics Ductwork
STANDARD OMPONENT DRAWINGS - CIRCULAR
FIG
94
DRAW G
I
~ 30deg 090deg
Breeches Piece
DETAILS
95 amp-----~ Blank End
~-----p Multi-Leaf Damper Can be piggolcd or fianged opposed or parallel blade
Alternative controls areshyri=-+- L-T~
I
---
LT~
I r- -
-+1
J HO Hand96
bMD Molori cd
PD Pneumatic
tl-shy bull
Single Bladed Damper 97 ~ saD
on-Return Damper Vertical application only 98 m~D
43
DW154 Sf1tcificatioll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG
99
100
101
102
DRAWING
$ I-
2hr
1 4hr
SD
~v I I
CO TINENTAL COWL
DETAILS
Iris Damper
Fi reS moke Dam persSleeves
2hr Ratillg
With installation frame
4br Rating
Smoke damper
Intumescent Sleeve
Access Openings
Access panel - removable
Access door shy hinged
fnspection cover
Discharge Continental Cowl
44
DW154 Sp(Cii(ltJll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
DRAWINGltIC DETAns
-
I
I
~
I I I High Velocity Discharge Terminal 103 I
I
I I
J I I 1 ~--
Offset Stack Discbarge Terminal 104 1
~ I e --(-
I
N
I
I
I~
I I Vertical Oischarge with Weather Cowl 105 I
--1--1 I
I
GAPI I
RTl AL DISC) lARGE WITH W ATIIER COWL
45
DW154 SpecUicatoll for Plastics Ductwork
STANDARD COMPONE T DRAWINGS - PLA TEQUIPMENTIMISCELLANEOU
FIG DRAWING DETAILS
106 ~~~ Rectangular Attenuator
107 ~- Circular Attenuator
108
~ Beod Attenuator
109 J ~(f) Heating Coil
110 J ftte Cooling Coil
III Jc[ Electric Heating Coil
112 X F
Humidifier
113 [H XX Axial Fan
114 ~fB1famp Noo-standard Ductwork Cross hntchillg (of any separate type) indicates by reference to a key any non DVil54 ductwork system
115 2llIIIIJIIIIIll Flexible Ductwork
46
DW154 SJeCUicll(iol1 for Plastics Ductwork
TABLE 12 - STANDARD ABBREVIAT ONS
ABBREVIATION FLL
AD Acces Door
AFF Axial Flow Fan
AHU Air Handling nit
All Aluminium
AP Acess Panel
AT Attenuator
AV Air enninal Unit
BE 81ank nd
BQ Blast ate Damper
CC Cooling Coil
CF Centrifugal Fan
CTA Cross alk Attenuator
CVU Constant Volume Unit
DP Drain Point
EEC Electric Heating Coil
El Expansion Joint
FAl Fresh Air Inlet
FA From Above
FB From Belo
fBPP Fabric Backed Polypropyl-ne Sheet
Flexle Flexible Connection
lexfD Flexible Du t
C False Ceiling CO an oil Unit
fD Fire Damper
FFL Finished Floor Level
FJ Flanged Joint
FOAM Rigid Polyurethane Self xtinguishing Foam
FOB Flat on Bottom
FOT Flat on Top
GAM Galvanised after ManufacttrJc
GRP Glass Reinforced Plastic
GSS Galvanised Sheet Steel
HC Heating oil
HD and controlled Damper
HH Hand Hole
HL High Level
HVD High Velocity Discharge
IC Inspection Cover
ID lri Damper
IFS Intumescent Fircleevc
47
DW154 Specification for Plastics Ductwork
TABLE 12 - STANDAR ABBREVIATION CONTINUED
ABBREVIATION
IU
L
tv1D
MS
NRD NTS
OBO
OE
PHD
PD
PP
PP
PRD
PVC
RFC
RSC
R
SBO
SO
S1 TST
SSL
TA
TB
TO TJ
TP
TV
TV
OS
UPVC
S
V
VAV
50 RSA
FULL
Induction Unit
Low Level
Motor controlled Damper
Mjld Steel
on Return Damper
at to cale
Opposed Blade Damper
Open End
Parallel Blade Damper
Pneumatic controlled Damper
Polypropylene
Self xtinguishing Polypropylene
Pressure Relief Damper
Polyvinyl Chloride
Rolled Form Chamlel
Rolled Steel Channel
R fUnit
Singl Blade Damper
Smoke Damper
Slip Joint
Stainl t el
tructural Slab Level
To Ab vc
To Blow
Top Down (In Direction of Flow)
Telescopic Joint
Test Point
TU111iog Vane
Top Up (In Direction of Flo )
Voles Otherwise Stated
Unpl3sticisecl Polyvinyl Chloride
Underside
Ultra Violet Light
Variable Air Volume
Rolled Steel Angle (Vith Size)
48
DW154 SJeriiflllioll for Plastics Ductwork
A2 DUCT PRESSUREAPPE DXA Ductwork con truct d to DWIl54 will bebullbullbullbullbullbullbullbullbullbullbullbullbullbull
Air Leakage From Ductwork To be read in conjunction with DW143 A practical guide to Ductwork Leakage Testing
CAUTION As highlighted ill both this docul1lenr and DW14 I lot ellough emphasis can be placed 01 the fact that except for high pressure class C the much more stringent ductwork constructional standard brolght about b the general acceptance of DW154 have irtlally negated the requirement for leakage-testing It is essential lO realise lhat except where it is mandatory this doclllllelll is nOl an endors ~lIlent of the rourine testing of ducts bllt purely a guide to outline the procedures for cononnity with the air leakage limits ill Table l Where the specified methods of assembly and
A3sealing of dlcls are u ed a vi ual inspection wil ordinarily sl~fll e for ver(iatioll of a well engineered and a ceptahfy airtight COl1strucrioll WHERE NOT MANDATORY DUCT LEAKAGE TESTING IS GENERALLY AN UNJUSTIFIED AND SUBSTANTIAL EXPENSE
A1 INTRODUCTION L akage from ducted air distribution systems is an Lmportant consideration in the design and operation of ventilatjon and air conditioning middotystems A ductviork t)ystem tbat ba limited air leakag within defiucd limits wiH cnsUft
that tile design characteristics of the sytem can be maintained It wilJ also ensure that energy and operatLonal cosb are maintained at optimum levels DucLwork constlucted and Ulstalled in accordance with DW154 should minimise a level of air leakage that it) appropriate to tll operating static air pre sur in tile system
A4However it is recouuised that tbe environment in wtJich middotystems are installed is not always conducive to achieving a predictable level of quality in term of system ajr leakage and it is therefore accepted that designer may sometimes require tlle ystem to be tested in part or in total It should be ecogni ed that the testing of duct systems add a ignificant cost to the installation and incur some extra tjm within the programme (Se 47 and 64 re mandatory te-sting)
manufactured to a structural standard that is compatible with the system operating pressure There are three classes of duct con truction to eorre pond with the three pre ure clas meations Class A Lo pressure ducts suita le for a maximum positive operating pressure of 500 Pascal and a maximum negative pressure of -500 Pascals Class B IVledium pressure ductmiddot suitable for a rnaxilnuJJl positive operafjn o pressure of 1000 Pascals and a maxllnum negative pre sure of -750 Pa cal Class C High pre sure ducts suitable for a maximum po ilive operating pressur of 2000 Pa cals and a maximum negativ pres ur of -750 Paltcals
LEAKAGE FROM DUCTWORK Leakao-e front pia tic air ducts occur at the joint~ and is therefore proportional to the total surface area orthe du twork in th system Tb level of leakage i imilarly related to tIle air pres ure in th du t system and whilst there LS n precis formula for calculating the level of air los it i generally accepted that leakage will increase in proportjon to pressure to rbe pOvver of 065 The effect of air leakage from high pressure velocit ductwork is critical tn terms of system perfomlan dege energy consumption and the risk of high frequency noise as ociated with leakage These problems are le critical with medium pressure 10 ity systems but should be con idered Low pres mevelocity ducts present the lowe~t
ri k in tenn of tbe effect of leakage on the operation of the s stern
SYSTEM LEAKAGE LOSS As there i no di ct relatLonship between th volume of air conv yed and the surface area f the ductwork sy tern required to match the building configuratmn it is difficult to express air leakage a a percentage of total air volume Similarly the operating pressure will vary throughollt lh 3 system and a leakage is related to pre me the calculations ar comple However it is generally ac epted tbat in typical good quaJjty systems the leakage from
49
DW154 Specificatioll for Plastics Ductwork
each class of duct llnd r operating condition will be io the region of CIa S A low pressure 6 Clas B medium pres un 3 Clas C high pressure 2
A5 SPECIFYING AIR LEAKAGE TESTING Re peeting both the co -t and programme implications a sociated with te ling du 1 for leakage the designer may for example indicate that a particular system is te ted as follow
a) High pressure ducts - all tested b) Medium pr ssure duets - 10 of the
ductwork shall be s eet d at random and tested
c) Low pre sure - unte ed In any case where a random te t i elected for medium pre sure ductmiddot the followin c1au~e is suggested for inclusion by the de ign r
The designer hall elect at random a maxirnwlI of 10 of the dUCl system to bt tested for air leakage The duct hall be tested af the pressure recommended in Table J3 for the assifi atiol for the ectiol1 of the ductwork that is to be tested The tests shall be carried Ollt as the work proceeds and prior to the application of thermal insulation In the event of test failure of the randomlY selected section the designer shall have The right to select two La1her e tiolls at random for resting Where succes ive failures are identified there shall be a Tight to require rhl COl11raCWr 10 apply remedial attention to the complete ductwork system Th contractor shall provide documented eviden e of the calculalions used to arrive (1
the allowable 10 I for the section to be tested and the client or his agent shall willess and sign the results of the test
able 13 Air leakage rates
Maximum leakage of duct work Static
prcssUft Low-pressure edium-prc-sure I Iigh-prebull me diJfercntial Class A Class B Class C
1 2 J 4 Pa Litres per second per quare metre of surface area 100 054 018 ZOO 084 028 300 110 037 400 132 044 500 153 051 600 058 019 700 064 021 800 069 023 900 075 025
1000 080 027 1100 1200 1300 1400 1500
029 030 032 033 035
1600 1700 1800 1900 2000
036 038 039 040 042
Note Recommend d mean test presures are highlighted iD bold type with the actual selection being left to tll test operator
50
DW154 Sfeeiieaioll for Plastics Ductwork
A9
A10
and air leakage classification for the y em under test
DESIGNERS CALCULATIONS The designer can middotaJculate with reasonable accuracy the predicted total loss from a ystem by
a) Calculating the operatin presure in each ection of the sy tern
b) Calculating the surface area of the ductwork in each correspondin pre lire s ction
c) Calulating the allowabl~ los at the operating pressure for each ection of the system (see table 13 for allowable leakage figures)
VARIABLE PRESSUR S IN SYSTEMS De igner can achieve significant co t saving by matchina operating pressures throughout the system to constmctional standard and appropriate air leakage testing eO the practice of specifying construction tandards for whole duct sy tems based on fan discharge pre sure may incur unnece sary costs on a project For example ome large sy terns ould well be classiC ed for I akage limits as follows
Plant room risers CJas C Main floor distriblltJou CIa B Low pre sure outlets Cla A
A6 SPECIAL CASES There may be ~itLlations on a project where circumstance dictate thal pecial consideration be given to containing air loss s eg a long mn of duclwork may incur a di -proportjonate level of air 10 s In ca es such as thi example the designer can specify an improved tandard of airtighmess ie 80 of alJo~able 10 s for la B Ju ts The designer sbould not specif a CIa C t sI at CIa s C pressure for a CIa s B ducl
A7 SUGG S ED RANGE OF TES ING
A8 TESTING OF PLANT ITEMS Items of inline pJant (eg Fig 106 to 115) will not normaUy be included in an air I akage test The dllctwork contractor may indud such itelllS in tbe te t jf rh quipm ot has a certificate of COnfOlnlity for Ihe pres ure clas
bull High pressure duct bull Medium pre sure ducts bull Low pre sur ducts bull Exposed extract syst ID bull Ceiling void extract
systems bull Secondary ducts from
VAV or fan coil units bull Flexjble duct bull Final connections and
branches to grille and diffusers
100 test See A5 Untested UDt sted
Untested
Untested Untested
Untested
SI
i
DW154 SJecijicafion for Plastics Ductwork
ig 116 Permitted leakage at various pressures
Leakage in litres per second per square metre duct surface area
Vgt
o ltgt 0 ltgt N
ltgt Cgt
0 0 cc
0 0
~
g =
g ~
c 0
J
ltgt 0 I
~ ] tn
ltgt ltgt
In ol
~ 0 ~ 8 ~
~
c ltgt ltgt
~ CJ
~ ~ ~ ~ 8
0shyij
~ ~ ~ t
ltgt ltgt 00
l
~
~ Q
c C
~ rshy
e ltgt
I 1
I Cgt ltgtv
c Co ~
~~ ~ 10
I
0 Cgt
fJshyq 410 ) 1 ltgt
ltgt N
~ shy ltgt ltgt
~ I 1
c
52
DW154 Specificatio for Plastics Ductwork
Example of a completed test sheet Test No
General
Name of job N~ jC43Pt(r2lef Building Repound ~(~~0
Part 1 - Physical details
a Section of duct work to be tested ~(diffPIfff~el1f3rd Floor
b Drawing Number g91~~ c ssure aSSJ L atlOn V~Jl~IRfYgtg~~lPre Cl T Class C
d Test static pressure -(9 raErq~ ~~~~-~~J~~~ ~~ ~~~~ll
Leakaoe factor 9~-tre3$ecMz I OM REFTOTABLE 13)e b bullbullbullbullbullbullbull
f Surface area of duct under test Q~tJJItetre$ CPROMCALCU TIO BELOW)bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull ampampamp bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull
g ]Vlaxi mum permitted leakage -~ (~i~~0 ~~r~~ ~~~l-~-11~ ~~~Q
Part 2 - Test particulars
a Duct static pressure reading 9QFt~q~ ~ middot~~~1 ~~
b Manufacturer and type of liow measuring d vice (-~~~cJ~Y-9Q7EYg c Range of measurement of now measuring device QtP)OQ~(e~~~0I~~~~1~I~ ~~~~~~W~
d Reading of flm measurin o device pmiddot IFROM RIO)ftscag ~
I (DERlVED [ROM CHART SUPPUED WITH RIG US 0 ud)1e Interpreted air flow leakage rate ~(~~~f~~~ (~l~~~~~~~~~~~~~~~~~I
f Duration ~~~~~norn~allY l~ lnil1Ut~~d~~~ it1~ W~ Date of test ~(lITled ut by Wltll s ed by ~ ~
(~lJ MIJLrr) (Si~rrfltJUYJ
Printed Name 1~g0f~ Printed Name ~~Y~9~ and Company 7jl~~~~~( UJd CompanY AB COII$Itallt8
Width and depth or diameter
Periphery ength Area
millimetreS millimetres metre qL1are metre
800 x 750 3100 1755 5440
600 x 650 2500 557 1193
300 x 300 1200 120 144
305 din 958 700 670
250 dia 785 450 353
TOTAL 8000
53
DW154 Specijilarion for Plastics Ductwork
pA XB
Guida ce No es For he ransport Handling and
Storage of uctwork
avoid damage to adjacent duct panels In somc ca es particularly on con acts calling f r repetitive sizes the use of timber jigs and spacers may be justified Where reduced bulk and greater protection are major factor such as consignments for export transporting ductwork in L shape sections may justify the increa ed ite as embly co ts
It is recommended that before a contract is finalised that consideration is given to the subject of site acces material handling and storage as tbcy havgt a strong influence on the cost efficiency of the overall activity of ductwOlk installation
B3 Handling To minilnise th risk of damage duct sections should be clearly identified and deliveries to site should be closely linked to the installation programme so as to avoid accumulation of
B1 Storage and Handling of Ra Material Material should be stored in suitably designed racking out of direct unJight Where possible the e racks should be metal to earth Edges of cut she t may be harp and protective gloves are advised Wearing teel toe-capped boots is recommended Most pIa tic sheet is manufactured with smootb mfaces andor is suppLied with protective coating Care must be taken to prevent accidental lippag of stacked materials Beiuoshy good electrical insulators the movement of stock unless earthed will allow the build up of stati All stock shapes are chemically stable at normal temperature Whil t some raw materials used in their manufacture may themselves pre ent a toxic hazard once incorporated into the lOck bape they no long r constitute such a hazard and no dermatitic bazard are known nor are any
unfiJied ductwork and minimise double handling It is important to recognise that ductwork panels joint and corners arc susceptible to damage and care must be taken wheu band ling such material through a site During handling individual item of duct work may be liable to light cross sectional deformation until thev become an integral pan of a completed ductwork system Whilst this may temporarily detract from its intended appearance thi deformation will not have any detrimental effect on the functionality of the finally a semblecl system Installation of duct work and asociated plant items ill illevitably involve manual handUng The responsibi Iiry of employers and employees to a ses the risk of personal injury during mallual handling operations is et out in the HS E publication L23 Guidance on Manual Handling Regulations 1992
environmental problems expected 84 Site storage
B2 fransport Large capacity vehicles with high-sided open or closed-top bodies are tlle mo t suitable for the transport of dllctwork Careful consideration should be given to the
Adequate floor space IDust be provided within tbe building for the site storage of ductvork Such storage shalt make due allowance for thc stOf(ne of ductwork in stacks such that access ~ egt
between them is of sufficient width to pennil the removal of item without interference to
unloading of transport on sit a not all siJes b n fit from the material handlino- and access facilities that exi [ in a manufacturing workshop such as crane- fork-lifts or loading bay Site handJiog facilities along with
adjoining sta ks Ductvork components should be positioned so a to avoid crushing Ductwork of small panel size may be stored horizontally however care should be exercised to ensure that tack sizes are limited 10 within
ehicular acce s restrictions may itilluence the type and ize of transport to be uWised
engtlls of ductwork should be positioned 0
the tmctural strength of the duct sections to prevent distortion of the lower sections within the stack
as to avoid crushing Lengths Witll projections such as branches and bends i1anges girths damper quadrauL should be loaded so as to
54
DW154 S1tciic(ltioll for Plastics Ductwork
85 Internal cleanliness of new ductwork The site storage of ductwork introduces the important cODsideration of maintaining the internal cleanliness of the ductwork R feren e should be made to HVCA documentshybull DWffM2 Guide to Good Practice - internal
Cleanliness of New Ductwork Installations If the above conditioDs can not be satisfied consideration should be given by tJle designer to amending the specification to include for Po t Installation Cleaning as covered by tJ1C HVCA documentshybull TRJ17 Guide to Good Practic - Cleanliness
of Ventilation Systems
APPE DIXC
Fi e Retardant inishes C1 Improvement in the fire retardancy of plastic
ducts can be achieved to varying degrees and is wholly dependent llPOll the surface coating laminating resin selected and construction specification adopted In some instances smoke emission is coILSidered equaUy with other speci fication requirernen ts of the materials resistance to ignition and bumjng It is therefore important for design rs to establ ish the clients and officers detailed requirements and not rely on a tbird party interpretation of fire resisting or fire retardant Where possible the specification should refer dir etly to compliance with a British or European Standard identifying the specific sections applicable There are various types of resin and mat rcLnforcements that can achieve a Class 1 surface spread of flame ratin o when tested according to BS476 Part 7 (1987) This test puts materials illto Class I - 4 in descending order of perfoDllance according to the rat and extent of flame spread over their surfac under standard beating conditions Materials should also be tested for flre propagarion to BS476 Part 6 (1989) Tbi tesr measures the amount and rate of heat evolved by the material when subjected to standard heating
conditions Test results are given as an index of Perfonnance (i) whicb is based on three sub indices (iJ (i1) (h) The higher the value of the Index of Performance (i) the greater is the material s contribution to fire growth The higher the value of the sub-index 0) rhe greater the ease of ignition aod flame spread The highest product performance classification as defined in Approved Document B of the Building Regulations is Class O This is acLlieved if a material surface of a composite ploduct i~ either a) composed throughout of materials of
limited combustibility or b) a Class I material which has a tlre
propagation index (i) of not more than 12 and sub-index (i l ) of nor more than 6
01 J Class 0 is not a cla$sif1cation identified in any British Standard test
There are resin system reported to be classified to Class O when tested to BS476 Pcl1S 6 and 7 however designers need to ensure that such sysrems can be applied to their proposed design In propriety resinmat system available the fabrication techniques and COITect application are critical to the integrity of the reinforcing and clas ificatiol1 For example in some systems the u e of a non-fire retardant gelcont on a fire retardant substrate would reduce the classification For further information see HVCA publication DW144 Appendix D
55
DW154 SplCijiClIliol1 for Plastics Ductwork
x Guidance otes For nspectmiddoton Servicing a d
Clean-ng Access Openings
D1 GE ERAL This appendix highlight in ummary fOI111
the acce considerations that hould be made by the design r iD terms of inspection servicing and cleaning Having considered the seop and the design of the dUCI work system relative to the guidelines outlined below the designer should clearly indicate which levels of acces should be incorporated into the manufacture of a new duct work system (See Table 14 and Note I b low it
D2 DESIGN CONSIDERATIONS
D21 In ptction and servicing requireshyments are set out in Section 15 of Lhis specification
D22 Cleaning requirements are set out in the HVCA pubUcation TRl7 Guide to Good Practice Clean Lines of Ventilation Systems and the guide tates The precise location ize and
type of access would be dependent on the type of ductwork cleaning inspection and te ting metbods to b adopted Care protection and standards of cleanliness prior LO cOlllmisionin o
are set out in th AV A publication DWITM2 Guide to Good Practice Internal Cleanliness of New Ductwork Installations and th guide state Wh re specific limits of cleanliness are required ductwork sball be cleaned after installation by a spcialist cleaning contractor It will b in the interests of tht desioner botb financially and practically to cunsider employing a specialist c1eauing contractor at tbe
outset of a contract to internally clean newly installed ductwork prior to bandover This approach would reali e the following benefit shyi) Tb actual numb r of cleaning
access panels could be detennined to suit the method of cleaning to be adopted (This may be 1 s than the maximum requiremen listed under Lev 13 of Table 14)
ii) Clear directions could b given to the ductwork contractor as to tJle size and location of cleaning access panels that are required to be fitted during the mauushyfaclunng pro s
iii) The specialist cleaning operation prior to commi ioning vould enable the cleaning contractor to verify the practical acee requirement for the future cleaning operation associated -vitb a regular maintenance programme
iv) A specialist cleaning operation prior to commissioning would allow the designer to omit from the speeilicatiolJ the DWrrM2 requirem nt for factory sealing protection wipe downs and capping-off
v) Specialist Ieall ill 0 to the measurable standard defin d in TR17 will allow an objective definition of cleanline to be achieved
Car ful consideration must be gIven by the designer to the practl aJ problems associated witb the manufacture and fitting of suitably si Led access panel on small cross section duct and on the circular faces of rouod and flat oval ducts in particular
D23 Special con ideration must be given by the de igner to the practical problems associated with gaining personnel access to heavily congested ceiling areas and multi-la red du twork systems This approach would avoid
56
DW154 Spfciication for Plastics Ductwork
the possibility of access panels being D3 ACCESS 0 IN-LINE EQUIPMENT incorporated into a ductwork system at the This appendix unly covers acc il1spection manufacturing stage that were later found in through the ductwork body adjacent to an item practice to be inaccessible for either ervicing of in-line equipment and not openings in the or cleaning activities equipment itself
able 14 Acce requirements for inspection servicing and cleaning
HVCA PUBLICATIO REFE NeE (uidtgt 10 Gund Prartict
Adjace t OW144 Cleanliness orVcnlillltio S~lcr~ fRjJ7
in-line LeyeJ 1 Level 2 Level 3 ite sequipment pcdionSen lcin~ Section d C1eaniJl( SUn(O)lnspc lion Palle ltk~m_n
2011 (minimum OiL Jubje-ct to duct ~zel (ft~ -Panels
Control Da pcrs One (inspection) 203 One 300 mm x 200 mm Both sid Fire Dampers One (sCTjdJl~) 20211 One 300 0101 x 200 mm One side HeatingCooling Coils One (inspedion) 20213 One 300 mm x 200 mm (lIpstream) Both sides Attenuators (rectangular) None required One 300 mm x 200 mm (downstream) Both sides Attenuators (circular) one retluired One 300 mm x 200 mm (downstream) One side Filter Sections One (inspection) 20212 one required Uoth sides Air Turn Vanes None requjred None required Both sides Changes of Direction None required one required One side In-Duct FansDevices One (inspection) 20213 None required Both sides l
1 In the absence of any indication by the designer only Level ) access will be jncorporated into a new ductwork system
2 Tbe panel izes associated with Lev lis I and 3 acee s ar e middottablished by reference to Section 20 of DW144 and Section 2 ofTRll7 respectively
57
DW154 Speclfifatio for Plastics Ductwork
pA XE
B-bliography Included in this Bibliography are technical pUblications which may be of interest (0 ductwork designers fabricators and erectors and to tho e in the heating ventilatlng air conditioning industries generally nquiric should be made of the relevant organisation at the address quoted Since its publication other addresse contained within 0V154 mav have changed and some pubJicalions may have been superseded
HEATING AND VENTILATING CONTRACTORS ASSOCIATION
4 Palace Court London W2 4JG Telephone 020-7229 2488 Fax 020-7727 9268
Orders fo FlY A Publications Old Matlsion House Eamont Bridge Penrith Cumbria CA 10 2BX (Telephone 01768 864771 Fax 01768 86718) Email hvcapoblicationshvwelfarecouk DWn 44 pe ilicatiun for sheet mctal duclwork (Iow- mediulllshy
and high-pressure) 1998) DWIl4 A practical guide to dUGI ork I akage te ting
(revised 2000) DWII54 Specification for plastic~ duct rk DW171 Guide to good Practice for kitchen venlibtion system DW191 Guide to good pracuce glass fibre ductwoJk DwrrMI Acceptance cheme for new products - Redangolar cro
joint classification Guide to good pra tice - Internal cleanliness of new ductwork installations Guide to good practice for the design for the Installation of lire and smoke uampers
J 1Other puhlications
HampV safely guide 5th edition JS2 Tool box talks JS5 Weldlng Safety booklet JSI9 afety facts bo klet Fact sheets 1-24 2nd edition JS2J COSHH manual volume 1 Advice on compliance with the
regulations 1521A CO I-rH manual volume 2 Asses mcnt h ets JS23 Ri k management manual TR3 BrazinltT and bronze welding of copper pipework cUld sheet
(I 976) TR5 Welding of carbon steel pipework (1980)
TR6 Guide to Good Practice for Site Pre sure Testing of Pipework (19 0) Guide to good practice cleanliness of ventilation Ylem
CHARTERED IN TITUTlO OF BUILDING SERVICES E G EERS Delta House 222 Balham High Road London SW12 9BS rTelephone 020-8675 5211 Fax 020-8675 5449) CIBSE Guide Volume A Design Data Volume B In tallatiol1 and quipment Data Volume C Reference Data
CommlssioniJIg Codes These Codes eover the preliminary checkS eUing to work and regulation of vanous catcgories 0 plan The Codes give a guide to design implications Series A Air Distnbution Systems Series B Boiler Plant
ri s C Automatic Conlrol ystems Cr1es R Refrigerating Sy terns
Sene iN Water Distribution Systems
Technkal Memonllda TM 4 Design Notes for the Middle East TM bull Design otes for Ductwork TM 13 Minimi iog lhc Risk of egiounaires Disease
Research Reports RROI95 Ventilation system hygiene - A review of published
infomlatioo on lhe occurrence and ffects of Olltamination Rl~02J95 Air-to-air heal rec v ry RR0395 rnfluen e of HV C on smoke detectors
ATlONAL ENI [ERING SPECIFICATION LfMITED Southgatc hamber 3739 Southgate Street Winchester S023 9EH (Telephone 01962 842058 Fax 01962 R(8982) BUfLDING S RVICES RESEARCH AND [ ORMATION ASSOCIATIO Old Bracknell Lane West Bracknell Berkshire RG 12 4AH (Telephone Brackl1eU (01344) 426511 Fax 01344 487 -7 )
Application Guides AGln4 De tglJing Vana~le Volume middotylans for KOOnl
iir Movement AG1I91 Commissioning of V Sylcms in Buildings 11 6194 Fire Dampers
B) 94 cntiJalion or KitcneTls
AG389 The Commls ionin of Air Systems In Buildmgs AH2192 Commissioning of Bern - A ~ode of Practice TN2417 I Fire Dampec il) Ventilating Ducl
BEATING VENTILATING A AIR CONDITION G MA UFACTURERS ASSOCIATIO (HEVAC) HEVAC Henley Road Medmenham Marlow Buck SU 2ER (Telephone 01491 578674 ox 01491 575024 Emoimiddot infofetacouk)
Publicatjons Air Diffusion Guide Guide to Air Handling Unit Leakage Testing Guide to Good Practice Air Handling Unit Real Room Acoustic ~ st Procedure Specification for the ertiiicatioll ofAir Filters Method of Test for Water Rejection PerfOnTlatce of Louvrcs Subjected 1(1
Simulated Rainfall Test Procedure for Acoustic Loo cs Specification 10 Floor GrilJes - Types Performan e and Method ofTest Specification for the Determination of the Collection Efficiency of SilJ1d
Trap Louvre Domestic Mechwlical Vclltllalion Systems with Heal Recovery Fan Application Guid
~an and Ouctwork Installation Guide Guide to Fan Noise and Vibration
pecification of Requirements for JallJral Smoke and Heal Exhausl Ventilators
pecification for Powered Smoke and Heat Exhaust Ventilators
Specification of Requirements for Smoke Curtains Design Gujue of Smoke Ventilation for Single Storey Lodustrilll Building~
Including those with Mezzanine Floor and IIi Racked Storage Warehou es - Issue 3
Guidance for the Design of Smoke entilation YSlem for Covered and Undergrollnd Car Parks - lssue 1
Application of SOloke Control Equipment and Syst m Guid to Good Practice - Isue J
58
DW154 Sp(C~tiifitiol for Plastics Ductwork
BRITISH STANDARDS INSTIT TION Sales Department 101 P ntooviLle Road London NI 9ND (felephone 020-78 1 78801)
CP 413 1973 Ducts for building ervices
SS 476 Fire tes on building matenals and lruc(ure
Part 4 19 4 Non-combustibility lest or materials
Part 6 I Fire propagation lest for materials
Part 7 1993 Surface spread of tlarnJ tesls for materia
Part 20 1987 Fir resistance of elements of construction
Part 21 1987 Fire r sistlUlce of loadbeanng elements of construction
Part 22 1987 Fhe istallceofllon-loadbearing elemcllts ofconsttuclion Part 23 1987 Contribution of componcnts to the fire resistance 0 a
structure
Part 24t987 Fire resi lance of wl1lilation ductl
SS 5588 nan 919 0 Fire Precautions III thc desIgn and OOSlnJ lion of buildings
S 729 1971 Hot dip galvanized oatiugs (or irOIl aod stcel articles
BS 1449 Steel plate sheet and Irip
Pan 11991 Carbon steel plate heel and strip Part 2 1983 Stainless steel plate sheer and strip
and
B middotENJOI49-2 996 BSEN 10149- 1991)
BSEN 10131 1992
BSEN22063 Sprayed metal coarings 1994 Protection of iron and steel by aluminium and zinc against
atmospheric cOlosion Irotectiotl of iron and ste I against corro ion and oxishydation at elevared temperatures
BS 353 1981 Glossary of lerms relnting to thermal insulation
BS ISO 1479 Self-tapplngscrewsandmetallicdri c crew
B -lSO 7049
1994
B 4800 1989 Painl colour for building purposes B 4848 l0 rolled structural steel sections
Part4 1972 Equal and unequal angles BS 5422 1990 Specification for the use of therm illuating matcriulS
SS 5720 1979 ode of practice for mechanical veutilating and air C 11shy
dirionin bull in building
l3S PR 12814-1 Bend resting for plasric welds
SS PR 12814-2 Tensile testing for plastic welds
SS PR 13067 Appro altesting for plastic welds
BS PR EN I 100-] Vi ual in pection ofplaslic welds
SHEET METAL AND AIR CONDITIONING CONTR-CTORS NATIONAL ASSOCIATION INC (SMACNA) Headquarters 420 I Lafayeue Center Drive Chanlilly Virginia 2051-1209
Mailing Address pa Box 221230 Cbantilly Virginilt120 153-1230
Telephone (703) 803-2980 Fax (703) 803-3732
Accepted IJJdustry Pl3Gtice for Industrial Duct Constnlelion 197 ) i-rchitecmral Sheet kwl Manual ([993)
Comractors Guide lor Modification 10 ooslruerion Colllraets 1993 Ducted Eleclric Heat Guide for ir Handling Ssrerns (1994)
En~rgy ollservatioD Guidelines (1984) Energy Recovery Equipment yslClllS (199l
Fibrou GIns Duct onS1ntClion Standards (1992)
Fire Smoke amp Radiation Damper In tall Guide for HVA Syst ms (1992) Guide t leel Stack 1(95)
HVA Air Duct Leakage Test Manual (19 ) HVA COlllmissioning lvlanual (1994)
H A Duct Construction Standards-Metal amp Flexible (1995) Addendum 01 (Nov 1997)
HVA Duct Systems Inspection Guide (1989)
HVA ySlems-Application (1986) nVAC ByternS-DLlct D ign (1990)
HVi Systems-Testing Adjusting amp Balancing (1993)
indoor Air Quality Manual (1993) tcheu quipment Fabrication Guidelmes (1990)
Managers Guide for elding (1993)
Rectangular Industrial Duct Cons1TUction Standards (19 0) Round Industrial Duct oustmction Standards (1977)
Sei mic Restraint Manual (1991) (wl Appendix E 1993) SMACNA Ma le Index ()fTechnical Publications (1995) Tbennoplnstic Duct CPY ) Construction Manual 1994)
DEPARTME OF THE ENVIRO MENT (Publications Centre) H Stationery Oflice 5 Nine Elms Lane London SWS 5DR
MampEJ 011972 Electrical in tallat1011 in buildings ( ew Editiou)
IampE 0319 Healing hot and cold wat r steam and gas losla1lations for buildings
M amp - No4 1970 Central heating and hot and cold ~ ateT in tallations for
dwelling
M amp ENo100 1971 Mechanical ventilation for building~
ASSOCIATION FOR SPECIALIST FIRE PROTECTlO As ociation House 235 Ash Road AJdershot Hampshire GUl2 4DD
Telephone OJ25221322 Fax 0 J252 333901
lublicalioos Fire Ratcd and moke Outlet Ducrwork An Industry Guide t Design and InSlalla lioll
HEALTH AND SAFETY EXEC TIVE Rose Court 2 Southwark Bridge London SEl 9HS Telephone 020-7717 6000
TWJ THE WELD G TlTUTE Abington Hall Abington Cambridge CB16AL Telepbone 0 J223 89162
Publication DatJ Oil w~ldll1g of lhermopla lics
59
DW154 wciiwlioll for Plastics Ductwork
A -=--DIX
Factors
Specific gravity shy pp = 091 approx UPVC = 14 approx
Some miscellaneous conversion factors
To convert
Length Inches to millimetres Feet to metres
Multiply by
2540 03048
To convert
Millimetres to inches Metres to feet
vIultiply by
003937 3281
Area Square inches to square millimetres 6452 Square millimetres to square inches 000155 Square feet to square metres 00929 Square metres to square feet 10764
Volume Cubic feet to cubic metres Cubic feet to litres Gallons (UK) to litres
002832 2831 4546
Cubic metres to cubic feet Litres to cubic feet Litres to gallons (UK)
35315 00353
022
Mass Ounces to grams Pounds to kiJograms Tons to tonnes
2835 04536
1016
Grams to ounces Kilograms to pounds Tonnes to tons
003527 2205
09842
Volume flow Cubic feet per minute to cubic Cubic metres per second to cubic
metres per second 0000472 feet per minute 2119 Cubic feet per mIDute to litres Litres per second to cubic feet
per second 04719 per minute 2119
Motion Feet per minute to metres per second 000508 Metres per second to feet per minute 197
Pressure Inches water gauge to millibars 2491 Inches wateJ- gauge to pascals (Pa) 2491 I Pa = I ewton per square metre = 10-2 millibars
60
Heating and Ventilating Contractors Association Esca House 34 Palace Court London W2 4JG
Tel 020 7313 4900
e-mail contact Itvcaorguk web site wwwhvcaorguk
Fax 020 7727 9268
DW154 SpecijicotiOll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG
78
79
80
81
DRAWING
-23~---pound3-(MALE) (FEMAJE)
-t=j--_j(--d-shy
--L
~ THROAT RADI S= D AS T NDARD
e ~
THROAT Rjf)lU = D A MU)
DETAILS
Straight Duct With male and female connectors
Straight Duct With flange joint and slip joint
Bend MouldedIFormed Applies to any angle ego 30deg45deg60deg90deg Medium radius bend as illustrated Long radius similar but throat radius 0
Segmented Bend 90deg four section minjmum as illustrated
Other Angles 60deg = 3 sections 45deg = 3 sections 30deg = 2 sections
I
i
40 shy
DW154 Speciicafinll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG DRAWING DETAlLS
82 Segmented Twin Bend Radius = D2 max
May also be fabricated from tube
83 Equal Tee MouldedIFormed
84 -~ 1in Bend MouldedIFormed
85 Taper Concentric 1 0 as iUu trated Eccentric 30deg iJJcLuded angle
86 Short Taper
41
DW154 SpcUicatol1 for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG DRAWING DETAILS
87 30 max Offset
Angle Branch
Bran h dUCI Dimcnsions dia (D) lA)
Shoe Branch mm mm 88 Cl
Off rectanguJur Up 10 200 75 lOO 10 400 125
- 00 150 Over 600 200
Bl1IllCh duct DimenlOns din (D) (A
~-$a-Conical Branch mm mm
89 Also acceptable with Up 10 200 r
full conical surface 300 10
400 125
END VrE -shy 600 150 Over 600 200
90
m 75
100 12 150 200
mm Up to 200
_ 300 400
600 Over 600
iUtred Branch
Shoe Branch
J-L----U ~ Bell oulh Branch
ENDV1EW
93
92
91
42
DW154 Specificatiol for Plastics Ductwork
STANDARD OMPONENT DRAWINGS - CIRCULAR
FIG
94
DRAW G
I
~ 30deg 090deg
Breeches Piece
DETAILS
95 amp-----~ Blank End
~-----p Multi-Leaf Damper Can be piggolcd or fianged opposed or parallel blade
Alternative controls areshyri=-+- L-T~
I
---
LT~
I r- -
-+1
J HO Hand96
bMD Molori cd
PD Pneumatic
tl-shy bull
Single Bladed Damper 97 ~ saD
on-Return Damper Vertical application only 98 m~D
43
DW154 Sf1tcificatioll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG
99
100
101
102
DRAWING
$ I-
2hr
1 4hr
SD
~v I I
CO TINENTAL COWL
DETAILS
Iris Damper
Fi reS moke Dam persSleeves
2hr Ratillg
With installation frame
4br Rating
Smoke damper
Intumescent Sleeve
Access Openings
Access panel - removable
Access door shy hinged
fnspection cover
Discharge Continental Cowl
44
DW154 Sp(Cii(ltJll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
DRAWINGltIC DETAns
-
I
I
~
I I I High Velocity Discharge Terminal 103 I
I
I I
J I I 1 ~--
Offset Stack Discbarge Terminal 104 1
~ I e --(-
I
N
I
I
I~
I I Vertical Oischarge with Weather Cowl 105 I
--1--1 I
I
GAPI I
RTl AL DISC) lARGE WITH W ATIIER COWL
45
DW154 SpecUicatoll for Plastics Ductwork
STANDARD COMPONE T DRAWINGS - PLA TEQUIPMENTIMISCELLANEOU
FIG DRAWING DETAILS
106 ~~~ Rectangular Attenuator
107 ~- Circular Attenuator
108
~ Beod Attenuator
109 J ~(f) Heating Coil
110 J ftte Cooling Coil
III Jc[ Electric Heating Coil
112 X F
Humidifier
113 [H XX Axial Fan
114 ~fB1famp Noo-standard Ductwork Cross hntchillg (of any separate type) indicates by reference to a key any non DVil54 ductwork system
115 2llIIIIJIIIIIll Flexible Ductwork
46
DW154 SJeCUicll(iol1 for Plastics Ductwork
TABLE 12 - STANDARD ABBREVIAT ONS
ABBREVIATION FLL
AD Acces Door
AFF Axial Flow Fan
AHU Air Handling nit
All Aluminium
AP Acess Panel
AT Attenuator
AV Air enninal Unit
BE 81ank nd
BQ Blast ate Damper
CC Cooling Coil
CF Centrifugal Fan
CTA Cross alk Attenuator
CVU Constant Volume Unit
DP Drain Point
EEC Electric Heating Coil
El Expansion Joint
FAl Fresh Air Inlet
FA From Above
FB From Belo
fBPP Fabric Backed Polypropyl-ne Sheet
Flexle Flexible Connection
lexfD Flexible Du t
C False Ceiling CO an oil Unit
fD Fire Damper
FFL Finished Floor Level
FJ Flanged Joint
FOAM Rigid Polyurethane Self xtinguishing Foam
FOB Flat on Bottom
FOT Flat on Top
GAM Galvanised after ManufacttrJc
GRP Glass Reinforced Plastic
GSS Galvanised Sheet Steel
HC Heating oil
HD and controlled Damper
HH Hand Hole
HL High Level
HVD High Velocity Discharge
IC Inspection Cover
ID lri Damper
IFS Intumescent Fircleevc
47
DW154 Specification for Plastics Ductwork
TABLE 12 - STANDAR ABBREVIATION CONTINUED
ABBREVIATION
IU
L
tv1D
MS
NRD NTS
OBO
OE
PHD
PD
PP
PP
PRD
PVC
RFC
RSC
R
SBO
SO
S1 TST
SSL
TA
TB
TO TJ
TP
TV
TV
OS
UPVC
S
V
VAV
50 RSA
FULL
Induction Unit
Low Level
Motor controlled Damper
Mjld Steel
on Return Damper
at to cale
Opposed Blade Damper
Open End
Parallel Blade Damper
Pneumatic controlled Damper
Polypropylene
Self xtinguishing Polypropylene
Pressure Relief Damper
Polyvinyl Chloride
Rolled Form Chamlel
Rolled Steel Channel
R fUnit
Singl Blade Damper
Smoke Damper
Slip Joint
Stainl t el
tructural Slab Level
To Ab vc
To Blow
Top Down (In Direction of Flow)
Telescopic Joint
Test Point
TU111iog Vane
Top Up (In Direction of Flo )
Voles Otherwise Stated
Unpl3sticisecl Polyvinyl Chloride
Underside
Ultra Violet Light
Variable Air Volume
Rolled Steel Angle (Vith Size)
48
DW154 SJeriiflllioll for Plastics Ductwork
A2 DUCT PRESSUREAPPE DXA Ductwork con truct d to DWIl54 will bebullbullbullbullbullbullbullbullbullbullbullbullbullbull
Air Leakage From Ductwork To be read in conjunction with DW143 A practical guide to Ductwork Leakage Testing
CAUTION As highlighted ill both this docul1lenr and DW14 I lot ellough emphasis can be placed 01 the fact that except for high pressure class C the much more stringent ductwork constructional standard brolght about b the general acceptance of DW154 have irtlally negated the requirement for leakage-testing It is essential lO realise lhat except where it is mandatory this doclllllelll is nOl an endors ~lIlent of the rourine testing of ducts bllt purely a guide to outline the procedures for cononnity with the air leakage limits ill Table l Where the specified methods of assembly and
A3sealing of dlcls are u ed a vi ual inspection wil ordinarily sl~fll e for ver(iatioll of a well engineered and a ceptahfy airtight COl1strucrioll WHERE NOT MANDATORY DUCT LEAKAGE TESTING IS GENERALLY AN UNJUSTIFIED AND SUBSTANTIAL EXPENSE
A1 INTRODUCTION L akage from ducted air distribution systems is an Lmportant consideration in the design and operation of ventilatjon and air conditioning middotystems A ductviork t)ystem tbat ba limited air leakag within defiucd limits wiH cnsUft
that tile design characteristics of the sytem can be maintained It wilJ also ensure that energy and operatLonal cosb are maintained at optimum levels DucLwork constlucted and Ulstalled in accordance with DW154 should minimise a level of air leakage that it) appropriate to tll operating static air pre sur in tile system
A4However it is recouuised that tbe environment in wtJich middotystems are installed is not always conducive to achieving a predictable level of quality in term of system ajr leakage and it is therefore accepted that designer may sometimes require tlle ystem to be tested in part or in total It should be ecogni ed that the testing of duct systems add a ignificant cost to the installation and incur some extra tjm within the programme (Se 47 and 64 re mandatory te-sting)
manufactured to a structural standard that is compatible with the system operating pressure There are three classes of duct con truction to eorre pond with the three pre ure clas meations Class A Lo pressure ducts suita le for a maximum positive operating pressure of 500 Pascal and a maximum negative pressure of -500 Pascals Class B IVledium pressure ductmiddot suitable for a rnaxilnuJJl positive operafjn o pressure of 1000 Pascals and a maxllnum negative pre sure of -750 Pa cal Class C High pre sure ducts suitable for a maximum po ilive operating pressur of 2000 Pa cals and a maximum negativ pres ur of -750 Paltcals
LEAKAGE FROM DUCTWORK Leakao-e front pia tic air ducts occur at the joint~ and is therefore proportional to the total surface area orthe du twork in th system Tb level of leakage i imilarly related to tIle air pres ure in th du t system and whilst there LS n precis formula for calculating the level of air los it i generally accepted that leakage will increase in proportjon to pressure to rbe pOvver of 065 The effect of air leakage from high pressure velocit ductwork is critical tn terms of system perfomlan dege energy consumption and the risk of high frequency noise as ociated with leakage These problems are le critical with medium pressure 10 ity systems but should be con idered Low pres mevelocity ducts present the lowe~t
ri k in tenn of tbe effect of leakage on the operation of the s stern
SYSTEM LEAKAGE LOSS As there i no di ct relatLonship between th volume of air conv yed and the surface area f the ductwork sy tern required to match the building configuratmn it is difficult to express air leakage a a percentage of total air volume Similarly the operating pressure will vary throughollt lh 3 system and a leakage is related to pre me the calculations ar comple However it is generally ac epted tbat in typical good quaJjty systems the leakage from
49
DW154 Specificatioll for Plastics Ductwork
each class of duct llnd r operating condition will be io the region of CIa S A low pressure 6 Clas B medium pres un 3 Clas C high pressure 2
A5 SPECIFYING AIR LEAKAGE TESTING Re peeting both the co -t and programme implications a sociated with te ling du 1 for leakage the designer may for example indicate that a particular system is te ted as follow
a) High pressure ducts - all tested b) Medium pr ssure duets - 10 of the
ductwork shall be s eet d at random and tested
c) Low pre sure - unte ed In any case where a random te t i elected for medium pre sure ductmiddot the followin c1au~e is suggested for inclusion by the de ign r
The designer hall elect at random a maxirnwlI of 10 of the dUCl system to bt tested for air leakage The duct hall be tested af the pressure recommended in Table J3 for the assifi atiol for the ectiol1 of the ductwork that is to be tested The tests shall be carried Ollt as the work proceeds and prior to the application of thermal insulation In the event of test failure of the randomlY selected section the designer shall have The right to select two La1her e tiolls at random for resting Where succes ive failures are identified there shall be a Tight to require rhl COl11raCWr 10 apply remedial attention to the complete ductwork system Th contractor shall provide documented eviden e of the calculalions used to arrive (1
the allowable 10 I for the section to be tested and the client or his agent shall willess and sign the results of the test
able 13 Air leakage rates
Maximum leakage of duct work Static
prcssUft Low-pressure edium-prc-sure I Iigh-prebull me diJfercntial Class A Class B Class C
1 2 J 4 Pa Litres per second per quare metre of surface area 100 054 018 ZOO 084 028 300 110 037 400 132 044 500 153 051 600 058 019 700 064 021 800 069 023 900 075 025
1000 080 027 1100 1200 1300 1400 1500
029 030 032 033 035
1600 1700 1800 1900 2000
036 038 039 040 042
Note Recommend d mean test presures are highlighted iD bold type with the actual selection being left to tll test operator
50
DW154 Sfeeiieaioll for Plastics Ductwork
A9
A10
and air leakage classification for the y em under test
DESIGNERS CALCULATIONS The designer can middotaJculate with reasonable accuracy the predicted total loss from a ystem by
a) Calculating the operatin presure in each ection of the sy tern
b) Calculating the surface area of the ductwork in each correspondin pre lire s ction
c) Calulating the allowabl~ los at the operating pressure for each ection of the system (see table 13 for allowable leakage figures)
VARIABLE PRESSUR S IN SYSTEMS De igner can achieve significant co t saving by matchina operating pressures throughout the system to constmctional standard and appropriate air leakage testing eO the practice of specifying construction tandards for whole duct sy tems based on fan discharge pre sure may incur unnece sary costs on a project For example ome large sy terns ould well be classiC ed for I akage limits as follows
Plant room risers CJas C Main floor distriblltJou CIa B Low pre sure outlets Cla A
A6 SPECIAL CASES There may be ~itLlations on a project where circumstance dictate thal pecial consideration be given to containing air loss s eg a long mn of duclwork may incur a di -proportjonate level of air 10 s In ca es such as thi example the designer can specify an improved tandard of airtighmess ie 80 of alJo~able 10 s for la B Ju ts The designer sbould not specif a CIa C t sI at CIa s C pressure for a CIa s B ducl
A7 SUGG S ED RANGE OF TES ING
A8 TESTING OF PLANT ITEMS Items of inline pJant (eg Fig 106 to 115) will not normaUy be included in an air I akage test The dllctwork contractor may indud such itelllS in tbe te t jf rh quipm ot has a certificate of COnfOlnlity for Ihe pres ure clas
bull High pressure duct bull Medium pre sure ducts bull Low pre sur ducts bull Exposed extract syst ID bull Ceiling void extract
systems bull Secondary ducts from
VAV or fan coil units bull Flexjble duct bull Final connections and
branches to grille and diffusers
100 test See A5 Untested UDt sted
Untested
Untested Untested
Untested
SI
i
DW154 SJecijicafion for Plastics Ductwork
ig 116 Permitted leakage at various pressures
Leakage in litres per second per square metre duct surface area
Vgt
o ltgt 0 ltgt N
ltgt Cgt
0 0 cc
0 0
~
g =
g ~
c 0
J
ltgt 0 I
~ ] tn
ltgt ltgt
In ol
~ 0 ~ 8 ~
~
c ltgt ltgt
~ CJ
~ ~ ~ ~ 8
0shyij
~ ~ ~ t
ltgt ltgt 00
l
~
~ Q
c C
~ rshy
e ltgt
I 1
I Cgt ltgtv
c Co ~
~~ ~ 10
I
0 Cgt
fJshyq 410 ) 1 ltgt
ltgt N
~ shy ltgt ltgt
~ I 1
c
52
DW154 Specificatio for Plastics Ductwork
Example of a completed test sheet Test No
General
Name of job N~ jC43Pt(r2lef Building Repound ~(~~0
Part 1 - Physical details
a Section of duct work to be tested ~(diffPIfff~el1f3rd Floor
b Drawing Number g91~~ c ssure aSSJ L atlOn V~Jl~IRfYgtg~~lPre Cl T Class C
d Test static pressure -(9 raErq~ ~~~~-~~J~~~ ~~ ~~~~ll
Leakaoe factor 9~-tre3$ecMz I OM REFTOTABLE 13)e b bullbullbullbullbullbullbull
f Surface area of duct under test Q~tJJItetre$ CPROMCALCU TIO BELOW)bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull ampampamp bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull
g ]Vlaxi mum permitted leakage -~ (~i~~0 ~~r~~ ~~~l-~-11~ ~~~Q
Part 2 - Test particulars
a Duct static pressure reading 9QFt~q~ ~ middot~~~1 ~~
b Manufacturer and type of liow measuring d vice (-~~~cJ~Y-9Q7EYg c Range of measurement of now measuring device QtP)OQ~(e~~~0I~~~~1~I~ ~~~~~~W~
d Reading of flm measurin o device pmiddot IFROM RIO)ftscag ~
I (DERlVED [ROM CHART SUPPUED WITH RIG US 0 ud)1e Interpreted air flow leakage rate ~(~~~f~~~ (~l~~~~~~~~~~~~~~~~~I
f Duration ~~~~~norn~allY l~ lnil1Ut~~d~~~ it1~ W~ Date of test ~(lITled ut by Wltll s ed by ~ ~
(~lJ MIJLrr) (Si~rrfltJUYJ
Printed Name 1~g0f~ Printed Name ~~Y~9~ and Company 7jl~~~~~( UJd CompanY AB COII$Itallt8
Width and depth or diameter
Periphery ength Area
millimetreS millimetres metre qL1are metre
800 x 750 3100 1755 5440
600 x 650 2500 557 1193
300 x 300 1200 120 144
305 din 958 700 670
250 dia 785 450 353
TOTAL 8000
53
DW154 Specijilarion for Plastics Ductwork
pA XB
Guida ce No es For he ransport Handling and
Storage of uctwork
avoid damage to adjacent duct panels In somc ca es particularly on con acts calling f r repetitive sizes the use of timber jigs and spacers may be justified Where reduced bulk and greater protection are major factor such as consignments for export transporting ductwork in L shape sections may justify the increa ed ite as embly co ts
It is recommended that before a contract is finalised that consideration is given to the subject of site acces material handling and storage as tbcy havgt a strong influence on the cost efficiency of the overall activity of ductwOlk installation
B3 Handling To minilnise th risk of damage duct sections should be clearly identified and deliveries to site should be closely linked to the installation programme so as to avoid accumulation of
B1 Storage and Handling of Ra Material Material should be stored in suitably designed racking out of direct unJight Where possible the e racks should be metal to earth Edges of cut she t may be harp and protective gloves are advised Wearing teel toe-capped boots is recommended Most pIa tic sheet is manufactured with smootb mfaces andor is suppLied with protective coating Care must be taken to prevent accidental lippag of stacked materials Beiuoshy good electrical insulators the movement of stock unless earthed will allow the build up of stati All stock shapes are chemically stable at normal temperature Whil t some raw materials used in their manufacture may themselves pre ent a toxic hazard once incorporated into the lOck bape they no long r constitute such a hazard and no dermatitic bazard are known nor are any
unfiJied ductwork and minimise double handling It is important to recognise that ductwork panels joint and corners arc susceptible to damage and care must be taken wheu band ling such material through a site During handling individual item of duct work may be liable to light cross sectional deformation until thev become an integral pan of a completed ductwork system Whilst this may temporarily detract from its intended appearance thi deformation will not have any detrimental effect on the functionality of the finally a semblecl system Installation of duct work and asociated plant items ill illevitably involve manual handUng The responsibi Iiry of employers and employees to a ses the risk of personal injury during mallual handling operations is et out in the HS E publication L23 Guidance on Manual Handling Regulations 1992
environmental problems expected 84 Site storage
B2 fransport Large capacity vehicles with high-sided open or closed-top bodies are tlle mo t suitable for the transport of dllctwork Careful consideration should be given to the
Adequate floor space IDust be provided within tbe building for the site storage of ductvork Such storage shalt make due allowance for thc stOf(ne of ductwork in stacks such that access ~ egt
between them is of sufficient width to pennil the removal of item without interference to
unloading of transport on sit a not all siJes b n fit from the material handlino- and access facilities that exi [ in a manufacturing workshop such as crane- fork-lifts or loading bay Site handJiog facilities along with
adjoining sta ks Ductvork components should be positioned so a to avoid crushing Ductwork of small panel size may be stored horizontally however care should be exercised to ensure that tack sizes are limited 10 within
ehicular acce s restrictions may itilluence the type and ize of transport to be uWised
engtlls of ductwork should be positioned 0
the tmctural strength of the duct sections to prevent distortion of the lower sections within the stack
as to avoid crushing Lengths Witll projections such as branches and bends i1anges girths damper quadrauL should be loaded so as to
54
DW154 S1tciic(ltioll for Plastics Ductwork
85 Internal cleanliness of new ductwork The site storage of ductwork introduces the important cODsideration of maintaining the internal cleanliness of the ductwork R feren e should be made to HVCA documentshybull DWffM2 Guide to Good Practice - internal
Cleanliness of New Ductwork Installations If the above conditioDs can not be satisfied consideration should be given by tJle designer to amending the specification to include for Po t Installation Cleaning as covered by tJ1C HVCA documentshybull TRJ17 Guide to Good Practic - Cleanliness
of Ventilation Systems
APPE DIXC
Fi e Retardant inishes C1 Improvement in the fire retardancy of plastic
ducts can be achieved to varying degrees and is wholly dependent llPOll the surface coating laminating resin selected and construction specification adopted In some instances smoke emission is coILSidered equaUy with other speci fication requirernen ts of the materials resistance to ignition and bumjng It is therefore important for design rs to establ ish the clients and officers detailed requirements and not rely on a tbird party interpretation of fire resisting or fire retardant Where possible the specification should refer dir etly to compliance with a British or European Standard identifying the specific sections applicable There are various types of resin and mat rcLnforcements that can achieve a Class 1 surface spread of flame ratin o when tested according to BS476 Part 7 (1987) This test puts materials illto Class I - 4 in descending order of perfoDllance according to the rat and extent of flame spread over their surfac under standard beating conditions Materials should also be tested for flre propagarion to BS476 Part 6 (1989) Tbi tesr measures the amount and rate of heat evolved by the material when subjected to standard heating
conditions Test results are given as an index of Perfonnance (i) whicb is based on three sub indices (iJ (i1) (h) The higher the value of the Index of Performance (i) the greater is the material s contribution to fire growth The higher the value of the sub-index 0) rhe greater the ease of ignition aod flame spread The highest product performance classification as defined in Approved Document B of the Building Regulations is Class O This is acLlieved if a material surface of a composite ploduct i~ either a) composed throughout of materials of
limited combustibility or b) a Class I material which has a tlre
propagation index (i) of not more than 12 and sub-index (i l ) of nor more than 6
01 J Class 0 is not a cla$sif1cation identified in any British Standard test
There are resin system reported to be classified to Class O when tested to BS476 Pcl1S 6 and 7 however designers need to ensure that such sysrems can be applied to their proposed design In propriety resinmat system available the fabrication techniques and COITect application are critical to the integrity of the reinforcing and clas ificatiol1 For example in some systems the u e of a non-fire retardant gelcont on a fire retardant substrate would reduce the classification For further information see HVCA publication DW144 Appendix D
55
DW154 SplCijiClIliol1 for Plastics Ductwork
x Guidance otes For nspectmiddoton Servicing a d
Clean-ng Access Openings
D1 GE ERAL This appendix highlight in ummary fOI111
the acce considerations that hould be made by the design r iD terms of inspection servicing and cleaning Having considered the seop and the design of the dUCI work system relative to the guidelines outlined below the designer should clearly indicate which levels of acces should be incorporated into the manufacture of a new duct work system (See Table 14 and Note I b low it
D2 DESIGN CONSIDERATIONS
D21 In ptction and servicing requireshyments are set out in Section 15 of Lhis specification
D22 Cleaning requirements are set out in the HVCA pubUcation TRl7 Guide to Good Practice Clean Lines of Ventilation Systems and the guide tates The precise location ize and
type of access would be dependent on the type of ductwork cleaning inspection and te ting metbods to b adopted Care protection and standards of cleanliness prior LO cOlllmisionin o
are set out in th AV A publication DWITM2 Guide to Good Practice Internal Cleanliness of New Ductwork Installations and th guide state Wh re specific limits of cleanliness are required ductwork sball be cleaned after installation by a spcialist cleaning contractor It will b in the interests of tht desioner botb financially and practically to cunsider employing a specialist c1eauing contractor at tbe
outset of a contract to internally clean newly installed ductwork prior to bandover This approach would reali e the following benefit shyi) Tb actual numb r of cleaning
access panels could be detennined to suit the method of cleaning to be adopted (This may be 1 s than the maximum requiremen listed under Lev 13 of Table 14)
ii) Clear directions could b given to the ductwork contractor as to tJle size and location of cleaning access panels that are required to be fitted during the mauushyfaclunng pro s
iii) The specialist cleaning operation prior to commi ioning vould enable the cleaning contractor to verify the practical acee requirement for the future cleaning operation associated -vitb a regular maintenance programme
iv) A specialist cleaning operation prior to commissioning would allow the designer to omit from the speeilicatiolJ the DWrrM2 requirem nt for factory sealing protection wipe downs and capping-off
v) Specialist Ieall ill 0 to the measurable standard defin d in TR17 will allow an objective definition of cleanline to be achieved
Car ful consideration must be gIven by the designer to the practl aJ problems associated witb the manufacture and fitting of suitably si Led access panel on small cross section duct and on the circular faces of rouod and flat oval ducts in particular
D23 Special con ideration must be given by the de igner to the practical problems associated with gaining personnel access to heavily congested ceiling areas and multi-la red du twork systems This approach would avoid
56
DW154 Spfciication for Plastics Ductwork
the possibility of access panels being D3 ACCESS 0 IN-LINE EQUIPMENT incorporated into a ductwork system at the This appendix unly covers acc il1spection manufacturing stage that were later found in through the ductwork body adjacent to an item practice to be inaccessible for either ervicing of in-line equipment and not openings in the or cleaning activities equipment itself
able 14 Acce requirements for inspection servicing and cleaning
HVCA PUBLICATIO REFE NeE (uidtgt 10 Gund Prartict
Adjace t OW144 Cleanliness orVcnlillltio S~lcr~ fRjJ7
in-line LeyeJ 1 Level 2 Level 3 ite sequipment pcdionSen lcin~ Section d C1eaniJl( SUn(O)lnspc lion Palle ltk~m_n
2011 (minimum OiL Jubje-ct to duct ~zel (ft~ -Panels
Control Da pcrs One (inspection) 203 One 300 mm x 200 mm Both sid Fire Dampers One (sCTjdJl~) 20211 One 300 0101 x 200 mm One side HeatingCooling Coils One (inspedion) 20213 One 300 mm x 200 mm (lIpstream) Both sides Attenuators (rectangular) None required One 300 mm x 200 mm (downstream) Both sides Attenuators (circular) one retluired One 300 mm x 200 mm (downstream) One side Filter Sections One (inspection) 20212 one required Uoth sides Air Turn Vanes None requjred None required Both sides Changes of Direction None required one required One side In-Duct FansDevices One (inspection) 20213 None required Both sides l
1 In the absence of any indication by the designer only Level ) access will be jncorporated into a new ductwork system
2 Tbe panel izes associated with Lev lis I and 3 acee s ar e middottablished by reference to Section 20 of DW144 and Section 2 ofTRll7 respectively
57
DW154 Speclfifatio for Plastics Ductwork
pA XE
B-bliography Included in this Bibliography are technical pUblications which may be of interest (0 ductwork designers fabricators and erectors and to tho e in the heating ventilatlng air conditioning industries generally nquiric should be made of the relevant organisation at the address quoted Since its publication other addresse contained within 0V154 mav have changed and some pubJicalions may have been superseded
HEATING AND VENTILATING CONTRACTORS ASSOCIATION
4 Palace Court London W2 4JG Telephone 020-7229 2488 Fax 020-7727 9268
Orders fo FlY A Publications Old Matlsion House Eamont Bridge Penrith Cumbria CA 10 2BX (Telephone 01768 864771 Fax 01768 86718) Email hvcapoblicationshvwelfarecouk DWn 44 pe ilicatiun for sheet mctal duclwork (Iow- mediulllshy
and high-pressure) 1998) DWIl4 A practical guide to dUGI ork I akage te ting
(revised 2000) DWII54 Specification for plastic~ duct rk DW171 Guide to good Practice for kitchen venlibtion system DW191 Guide to good pracuce glass fibre ductwoJk DwrrMI Acceptance cheme for new products - Redangolar cro
joint classification Guide to good pra tice - Internal cleanliness of new ductwork installations Guide to good practice for the design for the Installation of lire and smoke uampers
J 1Other puhlications
HampV safely guide 5th edition JS2 Tool box talks JS5 Weldlng Safety booklet JSI9 afety facts bo klet Fact sheets 1-24 2nd edition JS2J COSHH manual volume 1 Advice on compliance with the
regulations 1521A CO I-rH manual volume 2 Asses mcnt h ets JS23 Ri k management manual TR3 BrazinltT and bronze welding of copper pipework cUld sheet
(I 976) TR5 Welding of carbon steel pipework (1980)
TR6 Guide to Good Practice for Site Pre sure Testing of Pipework (19 0) Guide to good practice cleanliness of ventilation Ylem
CHARTERED IN TITUTlO OF BUILDING SERVICES E G EERS Delta House 222 Balham High Road London SW12 9BS rTelephone 020-8675 5211 Fax 020-8675 5449) CIBSE Guide Volume A Design Data Volume B In tallatiol1 and quipment Data Volume C Reference Data
CommlssioniJIg Codes These Codes eover the preliminary checkS eUing to work and regulation of vanous catcgories 0 plan The Codes give a guide to design implications Series A Air Distnbution Systems Series B Boiler Plant
ri s C Automatic Conlrol ystems Cr1es R Refrigerating Sy terns
Sene iN Water Distribution Systems
Technkal Memonllda TM 4 Design Notes for the Middle East TM bull Design otes for Ductwork TM 13 Minimi iog lhc Risk of egiounaires Disease
Research Reports RROI95 Ventilation system hygiene - A review of published
infomlatioo on lhe occurrence and ffects of Olltamination Rl~02J95 Air-to-air heal rec v ry RR0395 rnfluen e of HV C on smoke detectors
ATlONAL ENI [ERING SPECIFICATION LfMITED Southgatc hamber 3739 Southgate Street Winchester S023 9EH (Telephone 01962 842058 Fax 01962 R(8982) BUfLDING S RVICES RESEARCH AND [ ORMATION ASSOCIATIO Old Bracknell Lane West Bracknell Berkshire RG 12 4AH (Telephone Brackl1eU (01344) 426511 Fax 01344 487 -7 )
Application Guides AGln4 De tglJing Vana~le Volume middotylans for KOOnl
iir Movement AG1I91 Commissioning of V Sylcms in Buildings 11 6194 Fire Dampers
B) 94 cntiJalion or KitcneTls
AG389 The Commls ionin of Air Systems In Buildmgs AH2192 Commissioning of Bern - A ~ode of Practice TN2417 I Fire Dampec il) Ventilating Ducl
BEATING VENTILATING A AIR CONDITION G MA UFACTURERS ASSOCIATIO (HEVAC) HEVAC Henley Road Medmenham Marlow Buck SU 2ER (Telephone 01491 578674 ox 01491 575024 Emoimiddot infofetacouk)
Publicatjons Air Diffusion Guide Guide to Air Handling Unit Leakage Testing Guide to Good Practice Air Handling Unit Real Room Acoustic ~ st Procedure Specification for the ertiiicatioll ofAir Filters Method of Test for Water Rejection PerfOnTlatce of Louvrcs Subjected 1(1
Simulated Rainfall Test Procedure for Acoustic Loo cs Specification 10 Floor GrilJes - Types Performan e and Method ofTest Specification for the Determination of the Collection Efficiency of SilJ1d
Trap Louvre Domestic Mechwlical Vclltllalion Systems with Heal Recovery Fan Application Guid
~an and Ouctwork Installation Guide Guide to Fan Noise and Vibration
pecification of Requirements for JallJral Smoke and Heal Exhausl Ventilators
pecification for Powered Smoke and Heat Exhaust Ventilators
Specification of Requirements for Smoke Curtains Design Gujue of Smoke Ventilation for Single Storey Lodustrilll Building~
Including those with Mezzanine Floor and IIi Racked Storage Warehou es - Issue 3
Guidance for the Design of Smoke entilation YSlem for Covered and Undergrollnd Car Parks - lssue 1
Application of SOloke Control Equipment and Syst m Guid to Good Practice - Isue J
58
DW154 Sp(C~tiifitiol for Plastics Ductwork
BRITISH STANDARDS INSTIT TION Sales Department 101 P ntooviLle Road London NI 9ND (felephone 020-78 1 78801)
CP 413 1973 Ducts for building ervices
SS 476 Fire tes on building matenals and lruc(ure
Part 4 19 4 Non-combustibility lest or materials
Part 6 I Fire propagation lest for materials
Part 7 1993 Surface spread of tlarnJ tesls for materia
Part 20 1987 Fir resistance of elements of construction
Part 21 1987 Fire r sistlUlce of loadbeanng elements of construction
Part 22 1987 Fhe istallceofllon-loadbearing elemcllts ofconsttuclion Part 23 1987 Contribution of componcnts to the fire resistance 0 a
structure
Part 24t987 Fire resi lance of wl1lilation ductl
SS 5588 nan 919 0 Fire Precautions III thc desIgn and OOSlnJ lion of buildings
S 729 1971 Hot dip galvanized oatiugs (or irOIl aod stcel articles
BS 1449 Steel plate sheet and Irip
Pan 11991 Carbon steel plate heel and strip Part 2 1983 Stainless steel plate sheer and strip
and
B middotENJOI49-2 996 BSEN 10149- 1991)
BSEN 10131 1992
BSEN22063 Sprayed metal coarings 1994 Protection of iron and steel by aluminium and zinc against
atmospheric cOlosion Irotectiotl of iron and ste I against corro ion and oxishydation at elevared temperatures
BS 353 1981 Glossary of lerms relnting to thermal insulation
BS ISO 1479 Self-tapplngscrewsandmetallicdri c crew
B -lSO 7049
1994
B 4800 1989 Painl colour for building purposes B 4848 l0 rolled structural steel sections
Part4 1972 Equal and unequal angles BS 5422 1990 Specification for the use of therm illuating matcriulS
SS 5720 1979 ode of practice for mechanical veutilating and air C 11shy
dirionin bull in building
l3S PR 12814-1 Bend resting for plasric welds
SS PR 12814-2 Tensile testing for plastic welds
SS PR 13067 Appro altesting for plastic welds
BS PR EN I 100-] Vi ual in pection ofplaslic welds
SHEET METAL AND AIR CONDITIONING CONTR-CTORS NATIONAL ASSOCIATION INC (SMACNA) Headquarters 420 I Lafayeue Center Drive Chanlilly Virginia 2051-1209
Mailing Address pa Box 221230 Cbantilly Virginilt120 153-1230
Telephone (703) 803-2980 Fax (703) 803-3732
Accepted IJJdustry Pl3Gtice for Industrial Duct Constnlelion 197 ) i-rchitecmral Sheet kwl Manual ([993)
Comractors Guide lor Modification 10 ooslruerion Colllraets 1993 Ducted Eleclric Heat Guide for ir Handling Ssrerns (1994)
En~rgy ollservatioD Guidelines (1984) Energy Recovery Equipment yslClllS (199l
Fibrou GIns Duct onS1ntClion Standards (1992)
Fire Smoke amp Radiation Damper In tall Guide for HVA Syst ms (1992) Guide t leel Stack 1(95)
HVA Air Duct Leakage Test Manual (19 ) HVA COlllmissioning lvlanual (1994)
H A Duct Construction Standards-Metal amp Flexible (1995) Addendum 01 (Nov 1997)
HVA Duct Systems Inspection Guide (1989)
HVA ySlems-Application (1986) nVAC ByternS-DLlct D ign (1990)
HVi Systems-Testing Adjusting amp Balancing (1993)
indoor Air Quality Manual (1993) tcheu quipment Fabrication Guidelmes (1990)
Managers Guide for elding (1993)
Rectangular Industrial Duct Cons1TUction Standards (19 0) Round Industrial Duct oustmction Standards (1977)
Sei mic Restraint Manual (1991) (wl Appendix E 1993) SMACNA Ma le Index ()fTechnical Publications (1995) Tbennoplnstic Duct CPY ) Construction Manual 1994)
DEPARTME OF THE ENVIRO MENT (Publications Centre) H Stationery Oflice 5 Nine Elms Lane London SWS 5DR
MampEJ 011972 Electrical in tallat1011 in buildings ( ew Editiou)
IampE 0319 Healing hot and cold wat r steam and gas losla1lations for buildings
M amp - No4 1970 Central heating and hot and cold ~ ateT in tallations for
dwelling
M amp ENo100 1971 Mechanical ventilation for building~
ASSOCIATION FOR SPECIALIST FIRE PROTECTlO As ociation House 235 Ash Road AJdershot Hampshire GUl2 4DD
Telephone OJ25221322 Fax 0 J252 333901
lublicalioos Fire Ratcd and moke Outlet Ducrwork An Industry Guide t Design and InSlalla lioll
HEALTH AND SAFETY EXEC TIVE Rose Court 2 Southwark Bridge London SEl 9HS Telephone 020-7717 6000
TWJ THE WELD G TlTUTE Abington Hall Abington Cambridge CB16AL Telepbone 0 J223 89162
Publication DatJ Oil w~ldll1g of lhermopla lics
59
DW154 wciiwlioll for Plastics Ductwork
A -=--DIX
Factors
Specific gravity shy pp = 091 approx UPVC = 14 approx
Some miscellaneous conversion factors
To convert
Length Inches to millimetres Feet to metres
Multiply by
2540 03048
To convert
Millimetres to inches Metres to feet
vIultiply by
003937 3281
Area Square inches to square millimetres 6452 Square millimetres to square inches 000155 Square feet to square metres 00929 Square metres to square feet 10764
Volume Cubic feet to cubic metres Cubic feet to litres Gallons (UK) to litres
002832 2831 4546
Cubic metres to cubic feet Litres to cubic feet Litres to gallons (UK)
35315 00353
022
Mass Ounces to grams Pounds to kiJograms Tons to tonnes
2835 04536
1016
Grams to ounces Kilograms to pounds Tonnes to tons
003527 2205
09842
Volume flow Cubic feet per minute to cubic Cubic metres per second to cubic
metres per second 0000472 feet per minute 2119 Cubic feet per mIDute to litres Litres per second to cubic feet
per second 04719 per minute 2119
Motion Feet per minute to metres per second 000508 Metres per second to feet per minute 197
Pressure Inches water gauge to millibars 2491 Inches wateJ- gauge to pascals (Pa) 2491 I Pa = I ewton per square metre = 10-2 millibars
60
Heating and Ventilating Contractors Association Esca House 34 Palace Court London W2 4JG
Tel 020 7313 4900
e-mail contact Itvcaorguk web site wwwhvcaorguk
Fax 020 7727 9268
DW154 Speciicafinll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG DRAWING DETAlLS
82 Segmented Twin Bend Radius = D2 max
May also be fabricated from tube
83 Equal Tee MouldedIFormed
84 -~ 1in Bend MouldedIFormed
85 Taper Concentric 1 0 as iUu trated Eccentric 30deg iJJcLuded angle
86 Short Taper
41
DW154 SpcUicatol1 for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG DRAWING DETAILS
87 30 max Offset
Angle Branch
Bran h dUCI Dimcnsions dia (D) lA)
Shoe Branch mm mm 88 Cl
Off rectanguJur Up 10 200 75 lOO 10 400 125
- 00 150 Over 600 200
Bl1IllCh duct DimenlOns din (D) (A
~-$a-Conical Branch mm mm
89 Also acceptable with Up 10 200 r
full conical surface 300 10
400 125
END VrE -shy 600 150 Over 600 200
90
m 75
100 12 150 200
mm Up to 200
_ 300 400
600 Over 600
iUtred Branch
Shoe Branch
J-L----U ~ Bell oulh Branch
ENDV1EW
93
92
91
42
DW154 Specificatiol for Plastics Ductwork
STANDARD OMPONENT DRAWINGS - CIRCULAR
FIG
94
DRAW G
I
~ 30deg 090deg
Breeches Piece
DETAILS
95 amp-----~ Blank End
~-----p Multi-Leaf Damper Can be piggolcd or fianged opposed or parallel blade
Alternative controls areshyri=-+- L-T~
I
---
LT~
I r- -
-+1
J HO Hand96
bMD Molori cd
PD Pneumatic
tl-shy bull
Single Bladed Damper 97 ~ saD
on-Return Damper Vertical application only 98 m~D
43
DW154 Sf1tcificatioll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG
99
100
101
102
DRAWING
$ I-
2hr
1 4hr
SD
~v I I
CO TINENTAL COWL
DETAILS
Iris Damper
Fi reS moke Dam persSleeves
2hr Ratillg
With installation frame
4br Rating
Smoke damper
Intumescent Sleeve
Access Openings
Access panel - removable
Access door shy hinged
fnspection cover
Discharge Continental Cowl
44
DW154 Sp(Cii(ltJll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
DRAWINGltIC DETAns
-
I
I
~
I I I High Velocity Discharge Terminal 103 I
I
I I
J I I 1 ~--
Offset Stack Discbarge Terminal 104 1
~ I e --(-
I
N
I
I
I~
I I Vertical Oischarge with Weather Cowl 105 I
--1--1 I
I
GAPI I
RTl AL DISC) lARGE WITH W ATIIER COWL
45
DW154 SpecUicatoll for Plastics Ductwork
STANDARD COMPONE T DRAWINGS - PLA TEQUIPMENTIMISCELLANEOU
FIG DRAWING DETAILS
106 ~~~ Rectangular Attenuator
107 ~- Circular Attenuator
108
~ Beod Attenuator
109 J ~(f) Heating Coil
110 J ftte Cooling Coil
III Jc[ Electric Heating Coil
112 X F
Humidifier
113 [H XX Axial Fan
114 ~fB1famp Noo-standard Ductwork Cross hntchillg (of any separate type) indicates by reference to a key any non DVil54 ductwork system
115 2llIIIIJIIIIIll Flexible Ductwork
46
DW154 SJeCUicll(iol1 for Plastics Ductwork
TABLE 12 - STANDARD ABBREVIAT ONS
ABBREVIATION FLL
AD Acces Door
AFF Axial Flow Fan
AHU Air Handling nit
All Aluminium
AP Acess Panel
AT Attenuator
AV Air enninal Unit
BE 81ank nd
BQ Blast ate Damper
CC Cooling Coil
CF Centrifugal Fan
CTA Cross alk Attenuator
CVU Constant Volume Unit
DP Drain Point
EEC Electric Heating Coil
El Expansion Joint
FAl Fresh Air Inlet
FA From Above
FB From Belo
fBPP Fabric Backed Polypropyl-ne Sheet
Flexle Flexible Connection
lexfD Flexible Du t
C False Ceiling CO an oil Unit
fD Fire Damper
FFL Finished Floor Level
FJ Flanged Joint
FOAM Rigid Polyurethane Self xtinguishing Foam
FOB Flat on Bottom
FOT Flat on Top
GAM Galvanised after ManufacttrJc
GRP Glass Reinforced Plastic
GSS Galvanised Sheet Steel
HC Heating oil
HD and controlled Damper
HH Hand Hole
HL High Level
HVD High Velocity Discharge
IC Inspection Cover
ID lri Damper
IFS Intumescent Fircleevc
47
DW154 Specification for Plastics Ductwork
TABLE 12 - STANDAR ABBREVIATION CONTINUED
ABBREVIATION
IU
L
tv1D
MS
NRD NTS
OBO
OE
PHD
PD
PP
PP
PRD
PVC
RFC
RSC
R
SBO
SO
S1 TST
SSL
TA
TB
TO TJ
TP
TV
TV
OS
UPVC
S
V
VAV
50 RSA
FULL
Induction Unit
Low Level
Motor controlled Damper
Mjld Steel
on Return Damper
at to cale
Opposed Blade Damper
Open End
Parallel Blade Damper
Pneumatic controlled Damper
Polypropylene
Self xtinguishing Polypropylene
Pressure Relief Damper
Polyvinyl Chloride
Rolled Form Chamlel
Rolled Steel Channel
R fUnit
Singl Blade Damper
Smoke Damper
Slip Joint
Stainl t el
tructural Slab Level
To Ab vc
To Blow
Top Down (In Direction of Flow)
Telescopic Joint
Test Point
TU111iog Vane
Top Up (In Direction of Flo )
Voles Otherwise Stated
Unpl3sticisecl Polyvinyl Chloride
Underside
Ultra Violet Light
Variable Air Volume
Rolled Steel Angle (Vith Size)
48
DW154 SJeriiflllioll for Plastics Ductwork
A2 DUCT PRESSUREAPPE DXA Ductwork con truct d to DWIl54 will bebullbullbullbullbullbullbullbullbullbullbullbullbullbull
Air Leakage From Ductwork To be read in conjunction with DW143 A practical guide to Ductwork Leakage Testing
CAUTION As highlighted ill both this docul1lenr and DW14 I lot ellough emphasis can be placed 01 the fact that except for high pressure class C the much more stringent ductwork constructional standard brolght about b the general acceptance of DW154 have irtlally negated the requirement for leakage-testing It is essential lO realise lhat except where it is mandatory this doclllllelll is nOl an endors ~lIlent of the rourine testing of ducts bllt purely a guide to outline the procedures for cononnity with the air leakage limits ill Table l Where the specified methods of assembly and
A3sealing of dlcls are u ed a vi ual inspection wil ordinarily sl~fll e for ver(iatioll of a well engineered and a ceptahfy airtight COl1strucrioll WHERE NOT MANDATORY DUCT LEAKAGE TESTING IS GENERALLY AN UNJUSTIFIED AND SUBSTANTIAL EXPENSE
A1 INTRODUCTION L akage from ducted air distribution systems is an Lmportant consideration in the design and operation of ventilatjon and air conditioning middotystems A ductviork t)ystem tbat ba limited air leakag within defiucd limits wiH cnsUft
that tile design characteristics of the sytem can be maintained It wilJ also ensure that energy and operatLonal cosb are maintained at optimum levels DucLwork constlucted and Ulstalled in accordance with DW154 should minimise a level of air leakage that it) appropriate to tll operating static air pre sur in tile system
A4However it is recouuised that tbe environment in wtJich middotystems are installed is not always conducive to achieving a predictable level of quality in term of system ajr leakage and it is therefore accepted that designer may sometimes require tlle ystem to be tested in part or in total It should be ecogni ed that the testing of duct systems add a ignificant cost to the installation and incur some extra tjm within the programme (Se 47 and 64 re mandatory te-sting)
manufactured to a structural standard that is compatible with the system operating pressure There are three classes of duct con truction to eorre pond with the three pre ure clas meations Class A Lo pressure ducts suita le for a maximum positive operating pressure of 500 Pascal and a maximum negative pressure of -500 Pascals Class B IVledium pressure ductmiddot suitable for a rnaxilnuJJl positive operafjn o pressure of 1000 Pascals and a maxllnum negative pre sure of -750 Pa cal Class C High pre sure ducts suitable for a maximum po ilive operating pressur of 2000 Pa cals and a maximum negativ pres ur of -750 Paltcals
LEAKAGE FROM DUCTWORK Leakao-e front pia tic air ducts occur at the joint~ and is therefore proportional to the total surface area orthe du twork in th system Tb level of leakage i imilarly related to tIle air pres ure in th du t system and whilst there LS n precis formula for calculating the level of air los it i generally accepted that leakage will increase in proportjon to pressure to rbe pOvver of 065 The effect of air leakage from high pressure velocit ductwork is critical tn terms of system perfomlan dege energy consumption and the risk of high frequency noise as ociated with leakage These problems are le critical with medium pressure 10 ity systems but should be con idered Low pres mevelocity ducts present the lowe~t
ri k in tenn of tbe effect of leakage on the operation of the s stern
SYSTEM LEAKAGE LOSS As there i no di ct relatLonship between th volume of air conv yed and the surface area f the ductwork sy tern required to match the building configuratmn it is difficult to express air leakage a a percentage of total air volume Similarly the operating pressure will vary throughollt lh 3 system and a leakage is related to pre me the calculations ar comple However it is generally ac epted tbat in typical good quaJjty systems the leakage from
49
DW154 Specificatioll for Plastics Ductwork
each class of duct llnd r operating condition will be io the region of CIa S A low pressure 6 Clas B medium pres un 3 Clas C high pressure 2
A5 SPECIFYING AIR LEAKAGE TESTING Re peeting both the co -t and programme implications a sociated with te ling du 1 for leakage the designer may for example indicate that a particular system is te ted as follow
a) High pressure ducts - all tested b) Medium pr ssure duets - 10 of the
ductwork shall be s eet d at random and tested
c) Low pre sure - unte ed In any case where a random te t i elected for medium pre sure ductmiddot the followin c1au~e is suggested for inclusion by the de ign r
The designer hall elect at random a maxirnwlI of 10 of the dUCl system to bt tested for air leakage The duct hall be tested af the pressure recommended in Table J3 for the assifi atiol for the ectiol1 of the ductwork that is to be tested The tests shall be carried Ollt as the work proceeds and prior to the application of thermal insulation In the event of test failure of the randomlY selected section the designer shall have The right to select two La1her e tiolls at random for resting Where succes ive failures are identified there shall be a Tight to require rhl COl11raCWr 10 apply remedial attention to the complete ductwork system Th contractor shall provide documented eviden e of the calculalions used to arrive (1
the allowable 10 I for the section to be tested and the client or his agent shall willess and sign the results of the test
able 13 Air leakage rates
Maximum leakage of duct work Static
prcssUft Low-pressure edium-prc-sure I Iigh-prebull me diJfercntial Class A Class B Class C
1 2 J 4 Pa Litres per second per quare metre of surface area 100 054 018 ZOO 084 028 300 110 037 400 132 044 500 153 051 600 058 019 700 064 021 800 069 023 900 075 025
1000 080 027 1100 1200 1300 1400 1500
029 030 032 033 035
1600 1700 1800 1900 2000
036 038 039 040 042
Note Recommend d mean test presures are highlighted iD bold type with the actual selection being left to tll test operator
50
DW154 Sfeeiieaioll for Plastics Ductwork
A9
A10
and air leakage classification for the y em under test
DESIGNERS CALCULATIONS The designer can middotaJculate with reasonable accuracy the predicted total loss from a ystem by
a) Calculating the operatin presure in each ection of the sy tern
b) Calculating the surface area of the ductwork in each correspondin pre lire s ction
c) Calulating the allowabl~ los at the operating pressure for each ection of the system (see table 13 for allowable leakage figures)
VARIABLE PRESSUR S IN SYSTEMS De igner can achieve significant co t saving by matchina operating pressures throughout the system to constmctional standard and appropriate air leakage testing eO the practice of specifying construction tandards for whole duct sy tems based on fan discharge pre sure may incur unnece sary costs on a project For example ome large sy terns ould well be classiC ed for I akage limits as follows
Plant room risers CJas C Main floor distriblltJou CIa B Low pre sure outlets Cla A
A6 SPECIAL CASES There may be ~itLlations on a project where circumstance dictate thal pecial consideration be given to containing air loss s eg a long mn of duclwork may incur a di -proportjonate level of air 10 s In ca es such as thi example the designer can specify an improved tandard of airtighmess ie 80 of alJo~able 10 s for la B Ju ts The designer sbould not specif a CIa C t sI at CIa s C pressure for a CIa s B ducl
A7 SUGG S ED RANGE OF TES ING
A8 TESTING OF PLANT ITEMS Items of inline pJant (eg Fig 106 to 115) will not normaUy be included in an air I akage test The dllctwork contractor may indud such itelllS in tbe te t jf rh quipm ot has a certificate of COnfOlnlity for Ihe pres ure clas
bull High pressure duct bull Medium pre sure ducts bull Low pre sur ducts bull Exposed extract syst ID bull Ceiling void extract
systems bull Secondary ducts from
VAV or fan coil units bull Flexjble duct bull Final connections and
branches to grille and diffusers
100 test See A5 Untested UDt sted
Untested
Untested Untested
Untested
SI
i
DW154 SJecijicafion for Plastics Ductwork
ig 116 Permitted leakage at various pressures
Leakage in litres per second per square metre duct surface area
Vgt
o ltgt 0 ltgt N
ltgt Cgt
0 0 cc
0 0
~
g =
g ~
c 0
J
ltgt 0 I
~ ] tn
ltgt ltgt
In ol
~ 0 ~ 8 ~
~
c ltgt ltgt
~ CJ
~ ~ ~ ~ 8
0shyij
~ ~ ~ t
ltgt ltgt 00
l
~
~ Q
c C
~ rshy
e ltgt
I 1
I Cgt ltgtv
c Co ~
~~ ~ 10
I
0 Cgt
fJshyq 410 ) 1 ltgt
ltgt N
~ shy ltgt ltgt
~ I 1
c
52
DW154 Specificatio for Plastics Ductwork
Example of a completed test sheet Test No
General
Name of job N~ jC43Pt(r2lef Building Repound ~(~~0
Part 1 - Physical details
a Section of duct work to be tested ~(diffPIfff~el1f3rd Floor
b Drawing Number g91~~ c ssure aSSJ L atlOn V~Jl~IRfYgtg~~lPre Cl T Class C
d Test static pressure -(9 raErq~ ~~~~-~~J~~~ ~~ ~~~~ll
Leakaoe factor 9~-tre3$ecMz I OM REFTOTABLE 13)e b bullbullbullbullbullbullbull
f Surface area of duct under test Q~tJJItetre$ CPROMCALCU TIO BELOW)bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull ampampamp bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull
g ]Vlaxi mum permitted leakage -~ (~i~~0 ~~r~~ ~~~l-~-11~ ~~~Q
Part 2 - Test particulars
a Duct static pressure reading 9QFt~q~ ~ middot~~~1 ~~
b Manufacturer and type of liow measuring d vice (-~~~cJ~Y-9Q7EYg c Range of measurement of now measuring device QtP)OQ~(e~~~0I~~~~1~I~ ~~~~~~W~
d Reading of flm measurin o device pmiddot IFROM RIO)ftscag ~
I (DERlVED [ROM CHART SUPPUED WITH RIG US 0 ud)1e Interpreted air flow leakage rate ~(~~~f~~~ (~l~~~~~~~~~~~~~~~~~I
f Duration ~~~~~norn~allY l~ lnil1Ut~~d~~~ it1~ W~ Date of test ~(lITled ut by Wltll s ed by ~ ~
(~lJ MIJLrr) (Si~rrfltJUYJ
Printed Name 1~g0f~ Printed Name ~~Y~9~ and Company 7jl~~~~~( UJd CompanY AB COII$Itallt8
Width and depth or diameter
Periphery ength Area
millimetreS millimetres metre qL1are metre
800 x 750 3100 1755 5440
600 x 650 2500 557 1193
300 x 300 1200 120 144
305 din 958 700 670
250 dia 785 450 353
TOTAL 8000
53
DW154 Specijilarion for Plastics Ductwork
pA XB
Guida ce No es For he ransport Handling and
Storage of uctwork
avoid damage to adjacent duct panels In somc ca es particularly on con acts calling f r repetitive sizes the use of timber jigs and spacers may be justified Where reduced bulk and greater protection are major factor such as consignments for export transporting ductwork in L shape sections may justify the increa ed ite as embly co ts
It is recommended that before a contract is finalised that consideration is given to the subject of site acces material handling and storage as tbcy havgt a strong influence on the cost efficiency of the overall activity of ductwOlk installation
B3 Handling To minilnise th risk of damage duct sections should be clearly identified and deliveries to site should be closely linked to the installation programme so as to avoid accumulation of
B1 Storage and Handling of Ra Material Material should be stored in suitably designed racking out of direct unJight Where possible the e racks should be metal to earth Edges of cut she t may be harp and protective gloves are advised Wearing teel toe-capped boots is recommended Most pIa tic sheet is manufactured with smootb mfaces andor is suppLied with protective coating Care must be taken to prevent accidental lippag of stacked materials Beiuoshy good electrical insulators the movement of stock unless earthed will allow the build up of stati All stock shapes are chemically stable at normal temperature Whil t some raw materials used in their manufacture may themselves pre ent a toxic hazard once incorporated into the lOck bape they no long r constitute such a hazard and no dermatitic bazard are known nor are any
unfiJied ductwork and minimise double handling It is important to recognise that ductwork panels joint and corners arc susceptible to damage and care must be taken wheu band ling such material through a site During handling individual item of duct work may be liable to light cross sectional deformation until thev become an integral pan of a completed ductwork system Whilst this may temporarily detract from its intended appearance thi deformation will not have any detrimental effect on the functionality of the finally a semblecl system Installation of duct work and asociated plant items ill illevitably involve manual handUng The responsibi Iiry of employers and employees to a ses the risk of personal injury during mallual handling operations is et out in the HS E publication L23 Guidance on Manual Handling Regulations 1992
environmental problems expected 84 Site storage
B2 fransport Large capacity vehicles with high-sided open or closed-top bodies are tlle mo t suitable for the transport of dllctwork Careful consideration should be given to the
Adequate floor space IDust be provided within tbe building for the site storage of ductvork Such storage shalt make due allowance for thc stOf(ne of ductwork in stacks such that access ~ egt
between them is of sufficient width to pennil the removal of item without interference to
unloading of transport on sit a not all siJes b n fit from the material handlino- and access facilities that exi [ in a manufacturing workshop such as crane- fork-lifts or loading bay Site handJiog facilities along with
adjoining sta ks Ductvork components should be positioned so a to avoid crushing Ductwork of small panel size may be stored horizontally however care should be exercised to ensure that tack sizes are limited 10 within
ehicular acce s restrictions may itilluence the type and ize of transport to be uWised
engtlls of ductwork should be positioned 0
the tmctural strength of the duct sections to prevent distortion of the lower sections within the stack
as to avoid crushing Lengths Witll projections such as branches and bends i1anges girths damper quadrauL should be loaded so as to
54
DW154 S1tciic(ltioll for Plastics Ductwork
85 Internal cleanliness of new ductwork The site storage of ductwork introduces the important cODsideration of maintaining the internal cleanliness of the ductwork R feren e should be made to HVCA documentshybull DWffM2 Guide to Good Practice - internal
Cleanliness of New Ductwork Installations If the above conditioDs can not be satisfied consideration should be given by tJle designer to amending the specification to include for Po t Installation Cleaning as covered by tJ1C HVCA documentshybull TRJ17 Guide to Good Practic - Cleanliness
of Ventilation Systems
APPE DIXC
Fi e Retardant inishes C1 Improvement in the fire retardancy of plastic
ducts can be achieved to varying degrees and is wholly dependent llPOll the surface coating laminating resin selected and construction specification adopted In some instances smoke emission is coILSidered equaUy with other speci fication requirernen ts of the materials resistance to ignition and bumjng It is therefore important for design rs to establ ish the clients and officers detailed requirements and not rely on a tbird party interpretation of fire resisting or fire retardant Where possible the specification should refer dir etly to compliance with a British or European Standard identifying the specific sections applicable There are various types of resin and mat rcLnforcements that can achieve a Class 1 surface spread of flame ratin o when tested according to BS476 Part 7 (1987) This test puts materials illto Class I - 4 in descending order of perfoDllance according to the rat and extent of flame spread over their surfac under standard beating conditions Materials should also be tested for flre propagarion to BS476 Part 6 (1989) Tbi tesr measures the amount and rate of heat evolved by the material when subjected to standard heating
conditions Test results are given as an index of Perfonnance (i) whicb is based on three sub indices (iJ (i1) (h) The higher the value of the Index of Performance (i) the greater is the material s contribution to fire growth The higher the value of the sub-index 0) rhe greater the ease of ignition aod flame spread The highest product performance classification as defined in Approved Document B of the Building Regulations is Class O This is acLlieved if a material surface of a composite ploduct i~ either a) composed throughout of materials of
limited combustibility or b) a Class I material which has a tlre
propagation index (i) of not more than 12 and sub-index (i l ) of nor more than 6
01 J Class 0 is not a cla$sif1cation identified in any British Standard test
There are resin system reported to be classified to Class O when tested to BS476 Pcl1S 6 and 7 however designers need to ensure that such sysrems can be applied to their proposed design In propriety resinmat system available the fabrication techniques and COITect application are critical to the integrity of the reinforcing and clas ificatiol1 For example in some systems the u e of a non-fire retardant gelcont on a fire retardant substrate would reduce the classification For further information see HVCA publication DW144 Appendix D
55
DW154 SplCijiClIliol1 for Plastics Ductwork
x Guidance otes For nspectmiddoton Servicing a d
Clean-ng Access Openings
D1 GE ERAL This appendix highlight in ummary fOI111
the acce considerations that hould be made by the design r iD terms of inspection servicing and cleaning Having considered the seop and the design of the dUCI work system relative to the guidelines outlined below the designer should clearly indicate which levels of acces should be incorporated into the manufacture of a new duct work system (See Table 14 and Note I b low it
D2 DESIGN CONSIDERATIONS
D21 In ptction and servicing requireshyments are set out in Section 15 of Lhis specification
D22 Cleaning requirements are set out in the HVCA pubUcation TRl7 Guide to Good Practice Clean Lines of Ventilation Systems and the guide tates The precise location ize and
type of access would be dependent on the type of ductwork cleaning inspection and te ting metbods to b adopted Care protection and standards of cleanliness prior LO cOlllmisionin o
are set out in th AV A publication DWITM2 Guide to Good Practice Internal Cleanliness of New Ductwork Installations and th guide state Wh re specific limits of cleanliness are required ductwork sball be cleaned after installation by a spcialist cleaning contractor It will b in the interests of tht desioner botb financially and practically to cunsider employing a specialist c1eauing contractor at tbe
outset of a contract to internally clean newly installed ductwork prior to bandover This approach would reali e the following benefit shyi) Tb actual numb r of cleaning
access panels could be detennined to suit the method of cleaning to be adopted (This may be 1 s than the maximum requiremen listed under Lev 13 of Table 14)
ii) Clear directions could b given to the ductwork contractor as to tJle size and location of cleaning access panels that are required to be fitted during the mauushyfaclunng pro s
iii) The specialist cleaning operation prior to commi ioning vould enable the cleaning contractor to verify the practical acee requirement for the future cleaning operation associated -vitb a regular maintenance programme
iv) A specialist cleaning operation prior to commissioning would allow the designer to omit from the speeilicatiolJ the DWrrM2 requirem nt for factory sealing protection wipe downs and capping-off
v) Specialist Ieall ill 0 to the measurable standard defin d in TR17 will allow an objective definition of cleanline to be achieved
Car ful consideration must be gIven by the designer to the practl aJ problems associated witb the manufacture and fitting of suitably si Led access panel on small cross section duct and on the circular faces of rouod and flat oval ducts in particular
D23 Special con ideration must be given by the de igner to the practical problems associated with gaining personnel access to heavily congested ceiling areas and multi-la red du twork systems This approach would avoid
56
DW154 Spfciication for Plastics Ductwork
the possibility of access panels being D3 ACCESS 0 IN-LINE EQUIPMENT incorporated into a ductwork system at the This appendix unly covers acc il1spection manufacturing stage that were later found in through the ductwork body adjacent to an item practice to be inaccessible for either ervicing of in-line equipment and not openings in the or cleaning activities equipment itself
able 14 Acce requirements for inspection servicing and cleaning
HVCA PUBLICATIO REFE NeE (uidtgt 10 Gund Prartict
Adjace t OW144 Cleanliness orVcnlillltio S~lcr~ fRjJ7
in-line LeyeJ 1 Level 2 Level 3 ite sequipment pcdionSen lcin~ Section d C1eaniJl( SUn(O)lnspc lion Palle ltk~m_n
2011 (minimum OiL Jubje-ct to duct ~zel (ft~ -Panels
Control Da pcrs One (inspection) 203 One 300 mm x 200 mm Both sid Fire Dampers One (sCTjdJl~) 20211 One 300 0101 x 200 mm One side HeatingCooling Coils One (inspedion) 20213 One 300 mm x 200 mm (lIpstream) Both sides Attenuators (rectangular) None required One 300 mm x 200 mm (downstream) Both sides Attenuators (circular) one retluired One 300 mm x 200 mm (downstream) One side Filter Sections One (inspection) 20212 one required Uoth sides Air Turn Vanes None requjred None required Both sides Changes of Direction None required one required One side In-Duct FansDevices One (inspection) 20213 None required Both sides l
1 In the absence of any indication by the designer only Level ) access will be jncorporated into a new ductwork system
2 Tbe panel izes associated with Lev lis I and 3 acee s ar e middottablished by reference to Section 20 of DW144 and Section 2 ofTRll7 respectively
57
DW154 Speclfifatio for Plastics Ductwork
pA XE
B-bliography Included in this Bibliography are technical pUblications which may be of interest (0 ductwork designers fabricators and erectors and to tho e in the heating ventilatlng air conditioning industries generally nquiric should be made of the relevant organisation at the address quoted Since its publication other addresse contained within 0V154 mav have changed and some pubJicalions may have been superseded
HEATING AND VENTILATING CONTRACTORS ASSOCIATION
4 Palace Court London W2 4JG Telephone 020-7229 2488 Fax 020-7727 9268
Orders fo FlY A Publications Old Matlsion House Eamont Bridge Penrith Cumbria CA 10 2BX (Telephone 01768 864771 Fax 01768 86718) Email hvcapoblicationshvwelfarecouk DWn 44 pe ilicatiun for sheet mctal duclwork (Iow- mediulllshy
and high-pressure) 1998) DWIl4 A practical guide to dUGI ork I akage te ting
(revised 2000) DWII54 Specification for plastic~ duct rk DW171 Guide to good Practice for kitchen venlibtion system DW191 Guide to good pracuce glass fibre ductwoJk DwrrMI Acceptance cheme for new products - Redangolar cro
joint classification Guide to good pra tice - Internal cleanliness of new ductwork installations Guide to good practice for the design for the Installation of lire and smoke uampers
J 1Other puhlications
HampV safely guide 5th edition JS2 Tool box talks JS5 Weldlng Safety booklet JSI9 afety facts bo klet Fact sheets 1-24 2nd edition JS2J COSHH manual volume 1 Advice on compliance with the
regulations 1521A CO I-rH manual volume 2 Asses mcnt h ets JS23 Ri k management manual TR3 BrazinltT and bronze welding of copper pipework cUld sheet
(I 976) TR5 Welding of carbon steel pipework (1980)
TR6 Guide to Good Practice for Site Pre sure Testing of Pipework (19 0) Guide to good practice cleanliness of ventilation Ylem
CHARTERED IN TITUTlO OF BUILDING SERVICES E G EERS Delta House 222 Balham High Road London SW12 9BS rTelephone 020-8675 5211 Fax 020-8675 5449) CIBSE Guide Volume A Design Data Volume B In tallatiol1 and quipment Data Volume C Reference Data
CommlssioniJIg Codes These Codes eover the preliminary checkS eUing to work and regulation of vanous catcgories 0 plan The Codes give a guide to design implications Series A Air Distnbution Systems Series B Boiler Plant
ri s C Automatic Conlrol ystems Cr1es R Refrigerating Sy terns
Sene iN Water Distribution Systems
Technkal Memonllda TM 4 Design Notes for the Middle East TM bull Design otes for Ductwork TM 13 Minimi iog lhc Risk of egiounaires Disease
Research Reports RROI95 Ventilation system hygiene - A review of published
infomlatioo on lhe occurrence and ffects of Olltamination Rl~02J95 Air-to-air heal rec v ry RR0395 rnfluen e of HV C on smoke detectors
ATlONAL ENI [ERING SPECIFICATION LfMITED Southgatc hamber 3739 Southgate Street Winchester S023 9EH (Telephone 01962 842058 Fax 01962 R(8982) BUfLDING S RVICES RESEARCH AND [ ORMATION ASSOCIATIO Old Bracknell Lane West Bracknell Berkshire RG 12 4AH (Telephone Brackl1eU (01344) 426511 Fax 01344 487 -7 )
Application Guides AGln4 De tglJing Vana~le Volume middotylans for KOOnl
iir Movement AG1I91 Commissioning of V Sylcms in Buildings 11 6194 Fire Dampers
B) 94 cntiJalion or KitcneTls
AG389 The Commls ionin of Air Systems In Buildmgs AH2192 Commissioning of Bern - A ~ode of Practice TN2417 I Fire Dampec il) Ventilating Ducl
BEATING VENTILATING A AIR CONDITION G MA UFACTURERS ASSOCIATIO (HEVAC) HEVAC Henley Road Medmenham Marlow Buck SU 2ER (Telephone 01491 578674 ox 01491 575024 Emoimiddot infofetacouk)
Publicatjons Air Diffusion Guide Guide to Air Handling Unit Leakage Testing Guide to Good Practice Air Handling Unit Real Room Acoustic ~ st Procedure Specification for the ertiiicatioll ofAir Filters Method of Test for Water Rejection PerfOnTlatce of Louvrcs Subjected 1(1
Simulated Rainfall Test Procedure for Acoustic Loo cs Specification 10 Floor GrilJes - Types Performan e and Method ofTest Specification for the Determination of the Collection Efficiency of SilJ1d
Trap Louvre Domestic Mechwlical Vclltllalion Systems with Heal Recovery Fan Application Guid
~an and Ouctwork Installation Guide Guide to Fan Noise and Vibration
pecification of Requirements for JallJral Smoke and Heal Exhausl Ventilators
pecification for Powered Smoke and Heat Exhaust Ventilators
Specification of Requirements for Smoke Curtains Design Gujue of Smoke Ventilation for Single Storey Lodustrilll Building~
Including those with Mezzanine Floor and IIi Racked Storage Warehou es - Issue 3
Guidance for the Design of Smoke entilation YSlem for Covered and Undergrollnd Car Parks - lssue 1
Application of SOloke Control Equipment and Syst m Guid to Good Practice - Isue J
58
DW154 Sp(C~tiifitiol for Plastics Ductwork
BRITISH STANDARDS INSTIT TION Sales Department 101 P ntooviLle Road London NI 9ND (felephone 020-78 1 78801)
CP 413 1973 Ducts for building ervices
SS 476 Fire tes on building matenals and lruc(ure
Part 4 19 4 Non-combustibility lest or materials
Part 6 I Fire propagation lest for materials
Part 7 1993 Surface spread of tlarnJ tesls for materia
Part 20 1987 Fir resistance of elements of construction
Part 21 1987 Fire r sistlUlce of loadbeanng elements of construction
Part 22 1987 Fhe istallceofllon-loadbearing elemcllts ofconsttuclion Part 23 1987 Contribution of componcnts to the fire resistance 0 a
structure
Part 24t987 Fire resi lance of wl1lilation ductl
SS 5588 nan 919 0 Fire Precautions III thc desIgn and OOSlnJ lion of buildings
S 729 1971 Hot dip galvanized oatiugs (or irOIl aod stcel articles
BS 1449 Steel plate sheet and Irip
Pan 11991 Carbon steel plate heel and strip Part 2 1983 Stainless steel plate sheer and strip
and
B middotENJOI49-2 996 BSEN 10149- 1991)
BSEN 10131 1992
BSEN22063 Sprayed metal coarings 1994 Protection of iron and steel by aluminium and zinc against
atmospheric cOlosion Irotectiotl of iron and ste I against corro ion and oxishydation at elevared temperatures
BS 353 1981 Glossary of lerms relnting to thermal insulation
BS ISO 1479 Self-tapplngscrewsandmetallicdri c crew
B -lSO 7049
1994
B 4800 1989 Painl colour for building purposes B 4848 l0 rolled structural steel sections
Part4 1972 Equal and unequal angles BS 5422 1990 Specification for the use of therm illuating matcriulS
SS 5720 1979 ode of practice for mechanical veutilating and air C 11shy
dirionin bull in building
l3S PR 12814-1 Bend resting for plasric welds
SS PR 12814-2 Tensile testing for plastic welds
SS PR 13067 Appro altesting for plastic welds
BS PR EN I 100-] Vi ual in pection ofplaslic welds
SHEET METAL AND AIR CONDITIONING CONTR-CTORS NATIONAL ASSOCIATION INC (SMACNA) Headquarters 420 I Lafayeue Center Drive Chanlilly Virginia 2051-1209
Mailing Address pa Box 221230 Cbantilly Virginilt120 153-1230
Telephone (703) 803-2980 Fax (703) 803-3732
Accepted IJJdustry Pl3Gtice for Industrial Duct Constnlelion 197 ) i-rchitecmral Sheet kwl Manual ([993)
Comractors Guide lor Modification 10 ooslruerion Colllraets 1993 Ducted Eleclric Heat Guide for ir Handling Ssrerns (1994)
En~rgy ollservatioD Guidelines (1984) Energy Recovery Equipment yslClllS (199l
Fibrou GIns Duct onS1ntClion Standards (1992)
Fire Smoke amp Radiation Damper In tall Guide for HVA Syst ms (1992) Guide t leel Stack 1(95)
HVA Air Duct Leakage Test Manual (19 ) HVA COlllmissioning lvlanual (1994)
H A Duct Construction Standards-Metal amp Flexible (1995) Addendum 01 (Nov 1997)
HVA Duct Systems Inspection Guide (1989)
HVA ySlems-Application (1986) nVAC ByternS-DLlct D ign (1990)
HVi Systems-Testing Adjusting amp Balancing (1993)
indoor Air Quality Manual (1993) tcheu quipment Fabrication Guidelmes (1990)
Managers Guide for elding (1993)
Rectangular Industrial Duct Cons1TUction Standards (19 0) Round Industrial Duct oustmction Standards (1977)
Sei mic Restraint Manual (1991) (wl Appendix E 1993) SMACNA Ma le Index ()fTechnical Publications (1995) Tbennoplnstic Duct CPY ) Construction Manual 1994)
DEPARTME OF THE ENVIRO MENT (Publications Centre) H Stationery Oflice 5 Nine Elms Lane London SWS 5DR
MampEJ 011972 Electrical in tallat1011 in buildings ( ew Editiou)
IampE 0319 Healing hot and cold wat r steam and gas losla1lations for buildings
M amp - No4 1970 Central heating and hot and cold ~ ateT in tallations for
dwelling
M amp ENo100 1971 Mechanical ventilation for building~
ASSOCIATION FOR SPECIALIST FIRE PROTECTlO As ociation House 235 Ash Road AJdershot Hampshire GUl2 4DD
Telephone OJ25221322 Fax 0 J252 333901
lublicalioos Fire Ratcd and moke Outlet Ducrwork An Industry Guide t Design and InSlalla lioll
HEALTH AND SAFETY EXEC TIVE Rose Court 2 Southwark Bridge London SEl 9HS Telephone 020-7717 6000
TWJ THE WELD G TlTUTE Abington Hall Abington Cambridge CB16AL Telepbone 0 J223 89162
Publication DatJ Oil w~ldll1g of lhermopla lics
59
DW154 wciiwlioll for Plastics Ductwork
A -=--DIX
Factors
Specific gravity shy pp = 091 approx UPVC = 14 approx
Some miscellaneous conversion factors
To convert
Length Inches to millimetres Feet to metres
Multiply by
2540 03048
To convert
Millimetres to inches Metres to feet
vIultiply by
003937 3281
Area Square inches to square millimetres 6452 Square millimetres to square inches 000155 Square feet to square metres 00929 Square metres to square feet 10764
Volume Cubic feet to cubic metres Cubic feet to litres Gallons (UK) to litres
002832 2831 4546
Cubic metres to cubic feet Litres to cubic feet Litres to gallons (UK)
35315 00353
022
Mass Ounces to grams Pounds to kiJograms Tons to tonnes
2835 04536
1016
Grams to ounces Kilograms to pounds Tonnes to tons
003527 2205
09842
Volume flow Cubic feet per minute to cubic Cubic metres per second to cubic
metres per second 0000472 feet per minute 2119 Cubic feet per mIDute to litres Litres per second to cubic feet
per second 04719 per minute 2119
Motion Feet per minute to metres per second 000508 Metres per second to feet per minute 197
Pressure Inches water gauge to millibars 2491 Inches wateJ- gauge to pascals (Pa) 2491 I Pa = I ewton per square metre = 10-2 millibars
60
Heating and Ventilating Contractors Association Esca House 34 Palace Court London W2 4JG
Tel 020 7313 4900
e-mail contact Itvcaorguk web site wwwhvcaorguk
Fax 020 7727 9268
DW154 SpcUicatol1 for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG DRAWING DETAILS
87 30 max Offset
Angle Branch
Bran h dUCI Dimcnsions dia (D) lA)
Shoe Branch mm mm 88 Cl
Off rectanguJur Up 10 200 75 lOO 10 400 125
- 00 150 Over 600 200
Bl1IllCh duct DimenlOns din (D) (A
~-$a-Conical Branch mm mm
89 Also acceptable with Up 10 200 r
full conical surface 300 10
400 125
END VrE -shy 600 150 Over 600 200
90
m 75
100 12 150 200
mm Up to 200
_ 300 400
600 Over 600
iUtred Branch
Shoe Branch
J-L----U ~ Bell oulh Branch
ENDV1EW
93
92
91
42
DW154 Specificatiol for Plastics Ductwork
STANDARD OMPONENT DRAWINGS - CIRCULAR
FIG
94
DRAW G
I
~ 30deg 090deg
Breeches Piece
DETAILS
95 amp-----~ Blank End
~-----p Multi-Leaf Damper Can be piggolcd or fianged opposed or parallel blade
Alternative controls areshyri=-+- L-T~
I
---
LT~
I r- -
-+1
J HO Hand96
bMD Molori cd
PD Pneumatic
tl-shy bull
Single Bladed Damper 97 ~ saD
on-Return Damper Vertical application only 98 m~D
43
DW154 Sf1tcificatioll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG
99
100
101
102
DRAWING
$ I-
2hr
1 4hr
SD
~v I I
CO TINENTAL COWL
DETAILS
Iris Damper
Fi reS moke Dam persSleeves
2hr Ratillg
With installation frame
4br Rating
Smoke damper
Intumescent Sleeve
Access Openings
Access panel - removable
Access door shy hinged
fnspection cover
Discharge Continental Cowl
44
DW154 Sp(Cii(ltJll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
DRAWINGltIC DETAns
-
I
I
~
I I I High Velocity Discharge Terminal 103 I
I
I I
J I I 1 ~--
Offset Stack Discbarge Terminal 104 1
~ I e --(-
I
N
I
I
I~
I I Vertical Oischarge with Weather Cowl 105 I
--1--1 I
I
GAPI I
RTl AL DISC) lARGE WITH W ATIIER COWL
45
DW154 SpecUicatoll for Plastics Ductwork
STANDARD COMPONE T DRAWINGS - PLA TEQUIPMENTIMISCELLANEOU
FIG DRAWING DETAILS
106 ~~~ Rectangular Attenuator
107 ~- Circular Attenuator
108
~ Beod Attenuator
109 J ~(f) Heating Coil
110 J ftte Cooling Coil
III Jc[ Electric Heating Coil
112 X F
Humidifier
113 [H XX Axial Fan
114 ~fB1famp Noo-standard Ductwork Cross hntchillg (of any separate type) indicates by reference to a key any non DVil54 ductwork system
115 2llIIIIJIIIIIll Flexible Ductwork
46
DW154 SJeCUicll(iol1 for Plastics Ductwork
TABLE 12 - STANDARD ABBREVIAT ONS
ABBREVIATION FLL
AD Acces Door
AFF Axial Flow Fan
AHU Air Handling nit
All Aluminium
AP Acess Panel
AT Attenuator
AV Air enninal Unit
BE 81ank nd
BQ Blast ate Damper
CC Cooling Coil
CF Centrifugal Fan
CTA Cross alk Attenuator
CVU Constant Volume Unit
DP Drain Point
EEC Electric Heating Coil
El Expansion Joint
FAl Fresh Air Inlet
FA From Above
FB From Belo
fBPP Fabric Backed Polypropyl-ne Sheet
Flexle Flexible Connection
lexfD Flexible Du t
C False Ceiling CO an oil Unit
fD Fire Damper
FFL Finished Floor Level
FJ Flanged Joint
FOAM Rigid Polyurethane Self xtinguishing Foam
FOB Flat on Bottom
FOT Flat on Top
GAM Galvanised after ManufacttrJc
GRP Glass Reinforced Plastic
GSS Galvanised Sheet Steel
HC Heating oil
HD and controlled Damper
HH Hand Hole
HL High Level
HVD High Velocity Discharge
IC Inspection Cover
ID lri Damper
IFS Intumescent Fircleevc
47
DW154 Specification for Plastics Ductwork
TABLE 12 - STANDAR ABBREVIATION CONTINUED
ABBREVIATION
IU
L
tv1D
MS
NRD NTS
OBO
OE
PHD
PD
PP
PP
PRD
PVC
RFC
RSC
R
SBO
SO
S1 TST
SSL
TA
TB
TO TJ
TP
TV
TV
OS
UPVC
S
V
VAV
50 RSA
FULL
Induction Unit
Low Level
Motor controlled Damper
Mjld Steel
on Return Damper
at to cale
Opposed Blade Damper
Open End
Parallel Blade Damper
Pneumatic controlled Damper
Polypropylene
Self xtinguishing Polypropylene
Pressure Relief Damper
Polyvinyl Chloride
Rolled Form Chamlel
Rolled Steel Channel
R fUnit
Singl Blade Damper
Smoke Damper
Slip Joint
Stainl t el
tructural Slab Level
To Ab vc
To Blow
Top Down (In Direction of Flow)
Telescopic Joint
Test Point
TU111iog Vane
Top Up (In Direction of Flo )
Voles Otherwise Stated
Unpl3sticisecl Polyvinyl Chloride
Underside
Ultra Violet Light
Variable Air Volume
Rolled Steel Angle (Vith Size)
48
DW154 SJeriiflllioll for Plastics Ductwork
A2 DUCT PRESSUREAPPE DXA Ductwork con truct d to DWIl54 will bebullbullbullbullbullbullbullbullbullbullbullbullbullbull
Air Leakage From Ductwork To be read in conjunction with DW143 A practical guide to Ductwork Leakage Testing
CAUTION As highlighted ill both this docul1lenr and DW14 I lot ellough emphasis can be placed 01 the fact that except for high pressure class C the much more stringent ductwork constructional standard brolght about b the general acceptance of DW154 have irtlally negated the requirement for leakage-testing It is essential lO realise lhat except where it is mandatory this doclllllelll is nOl an endors ~lIlent of the rourine testing of ducts bllt purely a guide to outline the procedures for cononnity with the air leakage limits ill Table l Where the specified methods of assembly and
A3sealing of dlcls are u ed a vi ual inspection wil ordinarily sl~fll e for ver(iatioll of a well engineered and a ceptahfy airtight COl1strucrioll WHERE NOT MANDATORY DUCT LEAKAGE TESTING IS GENERALLY AN UNJUSTIFIED AND SUBSTANTIAL EXPENSE
A1 INTRODUCTION L akage from ducted air distribution systems is an Lmportant consideration in the design and operation of ventilatjon and air conditioning middotystems A ductviork t)ystem tbat ba limited air leakag within defiucd limits wiH cnsUft
that tile design characteristics of the sytem can be maintained It wilJ also ensure that energy and operatLonal cosb are maintained at optimum levels DucLwork constlucted and Ulstalled in accordance with DW154 should minimise a level of air leakage that it) appropriate to tll operating static air pre sur in tile system
A4However it is recouuised that tbe environment in wtJich middotystems are installed is not always conducive to achieving a predictable level of quality in term of system ajr leakage and it is therefore accepted that designer may sometimes require tlle ystem to be tested in part or in total It should be ecogni ed that the testing of duct systems add a ignificant cost to the installation and incur some extra tjm within the programme (Se 47 and 64 re mandatory te-sting)
manufactured to a structural standard that is compatible with the system operating pressure There are three classes of duct con truction to eorre pond with the three pre ure clas meations Class A Lo pressure ducts suita le for a maximum positive operating pressure of 500 Pascal and a maximum negative pressure of -500 Pascals Class B IVledium pressure ductmiddot suitable for a rnaxilnuJJl positive operafjn o pressure of 1000 Pascals and a maxllnum negative pre sure of -750 Pa cal Class C High pre sure ducts suitable for a maximum po ilive operating pressur of 2000 Pa cals and a maximum negativ pres ur of -750 Paltcals
LEAKAGE FROM DUCTWORK Leakao-e front pia tic air ducts occur at the joint~ and is therefore proportional to the total surface area orthe du twork in th system Tb level of leakage i imilarly related to tIle air pres ure in th du t system and whilst there LS n precis formula for calculating the level of air los it i generally accepted that leakage will increase in proportjon to pressure to rbe pOvver of 065 The effect of air leakage from high pressure velocit ductwork is critical tn terms of system perfomlan dege energy consumption and the risk of high frequency noise as ociated with leakage These problems are le critical with medium pressure 10 ity systems but should be con idered Low pres mevelocity ducts present the lowe~t
ri k in tenn of tbe effect of leakage on the operation of the s stern
SYSTEM LEAKAGE LOSS As there i no di ct relatLonship between th volume of air conv yed and the surface area f the ductwork sy tern required to match the building configuratmn it is difficult to express air leakage a a percentage of total air volume Similarly the operating pressure will vary throughollt lh 3 system and a leakage is related to pre me the calculations ar comple However it is generally ac epted tbat in typical good quaJjty systems the leakage from
49
DW154 Specificatioll for Plastics Ductwork
each class of duct llnd r operating condition will be io the region of CIa S A low pressure 6 Clas B medium pres un 3 Clas C high pressure 2
A5 SPECIFYING AIR LEAKAGE TESTING Re peeting both the co -t and programme implications a sociated with te ling du 1 for leakage the designer may for example indicate that a particular system is te ted as follow
a) High pressure ducts - all tested b) Medium pr ssure duets - 10 of the
ductwork shall be s eet d at random and tested
c) Low pre sure - unte ed In any case where a random te t i elected for medium pre sure ductmiddot the followin c1au~e is suggested for inclusion by the de ign r
The designer hall elect at random a maxirnwlI of 10 of the dUCl system to bt tested for air leakage The duct hall be tested af the pressure recommended in Table J3 for the assifi atiol for the ectiol1 of the ductwork that is to be tested The tests shall be carried Ollt as the work proceeds and prior to the application of thermal insulation In the event of test failure of the randomlY selected section the designer shall have The right to select two La1her e tiolls at random for resting Where succes ive failures are identified there shall be a Tight to require rhl COl11raCWr 10 apply remedial attention to the complete ductwork system Th contractor shall provide documented eviden e of the calculalions used to arrive (1
the allowable 10 I for the section to be tested and the client or his agent shall willess and sign the results of the test
able 13 Air leakage rates
Maximum leakage of duct work Static
prcssUft Low-pressure edium-prc-sure I Iigh-prebull me diJfercntial Class A Class B Class C
1 2 J 4 Pa Litres per second per quare metre of surface area 100 054 018 ZOO 084 028 300 110 037 400 132 044 500 153 051 600 058 019 700 064 021 800 069 023 900 075 025
1000 080 027 1100 1200 1300 1400 1500
029 030 032 033 035
1600 1700 1800 1900 2000
036 038 039 040 042
Note Recommend d mean test presures are highlighted iD bold type with the actual selection being left to tll test operator
50
DW154 Sfeeiieaioll for Plastics Ductwork
A9
A10
and air leakage classification for the y em under test
DESIGNERS CALCULATIONS The designer can middotaJculate with reasonable accuracy the predicted total loss from a ystem by
a) Calculating the operatin presure in each ection of the sy tern
b) Calculating the surface area of the ductwork in each correspondin pre lire s ction
c) Calulating the allowabl~ los at the operating pressure for each ection of the system (see table 13 for allowable leakage figures)
VARIABLE PRESSUR S IN SYSTEMS De igner can achieve significant co t saving by matchina operating pressures throughout the system to constmctional standard and appropriate air leakage testing eO the practice of specifying construction tandards for whole duct sy tems based on fan discharge pre sure may incur unnece sary costs on a project For example ome large sy terns ould well be classiC ed for I akage limits as follows
Plant room risers CJas C Main floor distriblltJou CIa B Low pre sure outlets Cla A
A6 SPECIAL CASES There may be ~itLlations on a project where circumstance dictate thal pecial consideration be given to containing air loss s eg a long mn of duclwork may incur a di -proportjonate level of air 10 s In ca es such as thi example the designer can specify an improved tandard of airtighmess ie 80 of alJo~able 10 s for la B Ju ts The designer sbould not specif a CIa C t sI at CIa s C pressure for a CIa s B ducl
A7 SUGG S ED RANGE OF TES ING
A8 TESTING OF PLANT ITEMS Items of inline pJant (eg Fig 106 to 115) will not normaUy be included in an air I akage test The dllctwork contractor may indud such itelllS in tbe te t jf rh quipm ot has a certificate of COnfOlnlity for Ihe pres ure clas
bull High pressure duct bull Medium pre sure ducts bull Low pre sur ducts bull Exposed extract syst ID bull Ceiling void extract
systems bull Secondary ducts from
VAV or fan coil units bull Flexjble duct bull Final connections and
branches to grille and diffusers
100 test See A5 Untested UDt sted
Untested
Untested Untested
Untested
SI
i
DW154 SJecijicafion for Plastics Ductwork
ig 116 Permitted leakage at various pressures
Leakage in litres per second per square metre duct surface area
Vgt
o ltgt 0 ltgt N
ltgt Cgt
0 0 cc
0 0
~
g =
g ~
c 0
J
ltgt 0 I
~ ] tn
ltgt ltgt
In ol
~ 0 ~ 8 ~
~
c ltgt ltgt
~ CJ
~ ~ ~ ~ 8
0shyij
~ ~ ~ t
ltgt ltgt 00
l
~
~ Q
c C
~ rshy
e ltgt
I 1
I Cgt ltgtv
c Co ~
~~ ~ 10
I
0 Cgt
fJshyq 410 ) 1 ltgt
ltgt N
~ shy ltgt ltgt
~ I 1
c
52
DW154 Specificatio for Plastics Ductwork
Example of a completed test sheet Test No
General
Name of job N~ jC43Pt(r2lef Building Repound ~(~~0
Part 1 - Physical details
a Section of duct work to be tested ~(diffPIfff~el1f3rd Floor
b Drawing Number g91~~ c ssure aSSJ L atlOn V~Jl~IRfYgtg~~lPre Cl T Class C
d Test static pressure -(9 raErq~ ~~~~-~~J~~~ ~~ ~~~~ll
Leakaoe factor 9~-tre3$ecMz I OM REFTOTABLE 13)e b bullbullbullbullbullbullbull
f Surface area of duct under test Q~tJJItetre$ CPROMCALCU TIO BELOW)bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull ampampamp bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull
g ]Vlaxi mum permitted leakage -~ (~i~~0 ~~r~~ ~~~l-~-11~ ~~~Q
Part 2 - Test particulars
a Duct static pressure reading 9QFt~q~ ~ middot~~~1 ~~
b Manufacturer and type of liow measuring d vice (-~~~cJ~Y-9Q7EYg c Range of measurement of now measuring device QtP)OQ~(e~~~0I~~~~1~I~ ~~~~~~W~
d Reading of flm measurin o device pmiddot IFROM RIO)ftscag ~
I (DERlVED [ROM CHART SUPPUED WITH RIG US 0 ud)1e Interpreted air flow leakage rate ~(~~~f~~~ (~l~~~~~~~~~~~~~~~~~I
f Duration ~~~~~norn~allY l~ lnil1Ut~~d~~~ it1~ W~ Date of test ~(lITled ut by Wltll s ed by ~ ~
(~lJ MIJLrr) (Si~rrfltJUYJ
Printed Name 1~g0f~ Printed Name ~~Y~9~ and Company 7jl~~~~~( UJd CompanY AB COII$Itallt8
Width and depth or diameter
Periphery ength Area
millimetreS millimetres metre qL1are metre
800 x 750 3100 1755 5440
600 x 650 2500 557 1193
300 x 300 1200 120 144
305 din 958 700 670
250 dia 785 450 353
TOTAL 8000
53
DW154 Specijilarion for Plastics Ductwork
pA XB
Guida ce No es For he ransport Handling and
Storage of uctwork
avoid damage to adjacent duct panels In somc ca es particularly on con acts calling f r repetitive sizes the use of timber jigs and spacers may be justified Where reduced bulk and greater protection are major factor such as consignments for export transporting ductwork in L shape sections may justify the increa ed ite as embly co ts
It is recommended that before a contract is finalised that consideration is given to the subject of site acces material handling and storage as tbcy havgt a strong influence on the cost efficiency of the overall activity of ductwOlk installation
B3 Handling To minilnise th risk of damage duct sections should be clearly identified and deliveries to site should be closely linked to the installation programme so as to avoid accumulation of
B1 Storage and Handling of Ra Material Material should be stored in suitably designed racking out of direct unJight Where possible the e racks should be metal to earth Edges of cut she t may be harp and protective gloves are advised Wearing teel toe-capped boots is recommended Most pIa tic sheet is manufactured with smootb mfaces andor is suppLied with protective coating Care must be taken to prevent accidental lippag of stacked materials Beiuoshy good electrical insulators the movement of stock unless earthed will allow the build up of stati All stock shapes are chemically stable at normal temperature Whil t some raw materials used in their manufacture may themselves pre ent a toxic hazard once incorporated into the lOck bape they no long r constitute such a hazard and no dermatitic bazard are known nor are any
unfiJied ductwork and minimise double handling It is important to recognise that ductwork panels joint and corners arc susceptible to damage and care must be taken wheu band ling such material through a site During handling individual item of duct work may be liable to light cross sectional deformation until thev become an integral pan of a completed ductwork system Whilst this may temporarily detract from its intended appearance thi deformation will not have any detrimental effect on the functionality of the finally a semblecl system Installation of duct work and asociated plant items ill illevitably involve manual handUng The responsibi Iiry of employers and employees to a ses the risk of personal injury during mallual handling operations is et out in the HS E publication L23 Guidance on Manual Handling Regulations 1992
environmental problems expected 84 Site storage
B2 fransport Large capacity vehicles with high-sided open or closed-top bodies are tlle mo t suitable for the transport of dllctwork Careful consideration should be given to the
Adequate floor space IDust be provided within tbe building for the site storage of ductvork Such storage shalt make due allowance for thc stOf(ne of ductwork in stacks such that access ~ egt
between them is of sufficient width to pennil the removal of item without interference to
unloading of transport on sit a not all siJes b n fit from the material handlino- and access facilities that exi [ in a manufacturing workshop such as crane- fork-lifts or loading bay Site handJiog facilities along with
adjoining sta ks Ductvork components should be positioned so a to avoid crushing Ductwork of small panel size may be stored horizontally however care should be exercised to ensure that tack sizes are limited 10 within
ehicular acce s restrictions may itilluence the type and ize of transport to be uWised
engtlls of ductwork should be positioned 0
the tmctural strength of the duct sections to prevent distortion of the lower sections within the stack
as to avoid crushing Lengths Witll projections such as branches and bends i1anges girths damper quadrauL should be loaded so as to
54
DW154 S1tciic(ltioll for Plastics Ductwork
85 Internal cleanliness of new ductwork The site storage of ductwork introduces the important cODsideration of maintaining the internal cleanliness of the ductwork R feren e should be made to HVCA documentshybull DWffM2 Guide to Good Practice - internal
Cleanliness of New Ductwork Installations If the above conditioDs can not be satisfied consideration should be given by tJle designer to amending the specification to include for Po t Installation Cleaning as covered by tJ1C HVCA documentshybull TRJ17 Guide to Good Practic - Cleanliness
of Ventilation Systems
APPE DIXC
Fi e Retardant inishes C1 Improvement in the fire retardancy of plastic
ducts can be achieved to varying degrees and is wholly dependent llPOll the surface coating laminating resin selected and construction specification adopted In some instances smoke emission is coILSidered equaUy with other speci fication requirernen ts of the materials resistance to ignition and bumjng It is therefore important for design rs to establ ish the clients and officers detailed requirements and not rely on a tbird party interpretation of fire resisting or fire retardant Where possible the specification should refer dir etly to compliance with a British or European Standard identifying the specific sections applicable There are various types of resin and mat rcLnforcements that can achieve a Class 1 surface spread of flame ratin o when tested according to BS476 Part 7 (1987) This test puts materials illto Class I - 4 in descending order of perfoDllance according to the rat and extent of flame spread over their surfac under standard beating conditions Materials should also be tested for flre propagarion to BS476 Part 6 (1989) Tbi tesr measures the amount and rate of heat evolved by the material when subjected to standard heating
conditions Test results are given as an index of Perfonnance (i) whicb is based on three sub indices (iJ (i1) (h) The higher the value of the Index of Performance (i) the greater is the material s contribution to fire growth The higher the value of the sub-index 0) rhe greater the ease of ignition aod flame spread The highest product performance classification as defined in Approved Document B of the Building Regulations is Class O This is acLlieved if a material surface of a composite ploduct i~ either a) composed throughout of materials of
limited combustibility or b) a Class I material which has a tlre
propagation index (i) of not more than 12 and sub-index (i l ) of nor more than 6
01 J Class 0 is not a cla$sif1cation identified in any British Standard test
There are resin system reported to be classified to Class O when tested to BS476 Pcl1S 6 and 7 however designers need to ensure that such sysrems can be applied to their proposed design In propriety resinmat system available the fabrication techniques and COITect application are critical to the integrity of the reinforcing and clas ificatiol1 For example in some systems the u e of a non-fire retardant gelcont on a fire retardant substrate would reduce the classification For further information see HVCA publication DW144 Appendix D
55
DW154 SplCijiClIliol1 for Plastics Ductwork
x Guidance otes For nspectmiddoton Servicing a d
Clean-ng Access Openings
D1 GE ERAL This appendix highlight in ummary fOI111
the acce considerations that hould be made by the design r iD terms of inspection servicing and cleaning Having considered the seop and the design of the dUCI work system relative to the guidelines outlined below the designer should clearly indicate which levels of acces should be incorporated into the manufacture of a new duct work system (See Table 14 and Note I b low it
D2 DESIGN CONSIDERATIONS
D21 In ptction and servicing requireshyments are set out in Section 15 of Lhis specification
D22 Cleaning requirements are set out in the HVCA pubUcation TRl7 Guide to Good Practice Clean Lines of Ventilation Systems and the guide tates The precise location ize and
type of access would be dependent on the type of ductwork cleaning inspection and te ting metbods to b adopted Care protection and standards of cleanliness prior LO cOlllmisionin o
are set out in th AV A publication DWITM2 Guide to Good Practice Internal Cleanliness of New Ductwork Installations and th guide state Wh re specific limits of cleanliness are required ductwork sball be cleaned after installation by a spcialist cleaning contractor It will b in the interests of tht desioner botb financially and practically to cunsider employing a specialist c1eauing contractor at tbe
outset of a contract to internally clean newly installed ductwork prior to bandover This approach would reali e the following benefit shyi) Tb actual numb r of cleaning
access panels could be detennined to suit the method of cleaning to be adopted (This may be 1 s than the maximum requiremen listed under Lev 13 of Table 14)
ii) Clear directions could b given to the ductwork contractor as to tJle size and location of cleaning access panels that are required to be fitted during the mauushyfaclunng pro s
iii) The specialist cleaning operation prior to commi ioning vould enable the cleaning contractor to verify the practical acee requirement for the future cleaning operation associated -vitb a regular maintenance programme
iv) A specialist cleaning operation prior to commissioning would allow the designer to omit from the speeilicatiolJ the DWrrM2 requirem nt for factory sealing protection wipe downs and capping-off
v) Specialist Ieall ill 0 to the measurable standard defin d in TR17 will allow an objective definition of cleanline to be achieved
Car ful consideration must be gIven by the designer to the practl aJ problems associated witb the manufacture and fitting of suitably si Led access panel on small cross section duct and on the circular faces of rouod and flat oval ducts in particular
D23 Special con ideration must be given by the de igner to the practical problems associated with gaining personnel access to heavily congested ceiling areas and multi-la red du twork systems This approach would avoid
56
DW154 Spfciication for Plastics Ductwork
the possibility of access panels being D3 ACCESS 0 IN-LINE EQUIPMENT incorporated into a ductwork system at the This appendix unly covers acc il1spection manufacturing stage that were later found in through the ductwork body adjacent to an item practice to be inaccessible for either ervicing of in-line equipment and not openings in the or cleaning activities equipment itself
able 14 Acce requirements for inspection servicing and cleaning
HVCA PUBLICATIO REFE NeE (uidtgt 10 Gund Prartict
Adjace t OW144 Cleanliness orVcnlillltio S~lcr~ fRjJ7
in-line LeyeJ 1 Level 2 Level 3 ite sequipment pcdionSen lcin~ Section d C1eaniJl( SUn(O)lnspc lion Palle ltk~m_n
2011 (minimum OiL Jubje-ct to duct ~zel (ft~ -Panels
Control Da pcrs One (inspection) 203 One 300 mm x 200 mm Both sid Fire Dampers One (sCTjdJl~) 20211 One 300 0101 x 200 mm One side HeatingCooling Coils One (inspedion) 20213 One 300 mm x 200 mm (lIpstream) Both sides Attenuators (rectangular) None required One 300 mm x 200 mm (downstream) Both sides Attenuators (circular) one retluired One 300 mm x 200 mm (downstream) One side Filter Sections One (inspection) 20212 one required Uoth sides Air Turn Vanes None requjred None required Both sides Changes of Direction None required one required One side In-Duct FansDevices One (inspection) 20213 None required Both sides l
1 In the absence of any indication by the designer only Level ) access will be jncorporated into a new ductwork system
2 Tbe panel izes associated with Lev lis I and 3 acee s ar e middottablished by reference to Section 20 of DW144 and Section 2 ofTRll7 respectively
57
DW154 Speclfifatio for Plastics Ductwork
pA XE
B-bliography Included in this Bibliography are technical pUblications which may be of interest (0 ductwork designers fabricators and erectors and to tho e in the heating ventilatlng air conditioning industries generally nquiric should be made of the relevant organisation at the address quoted Since its publication other addresse contained within 0V154 mav have changed and some pubJicalions may have been superseded
HEATING AND VENTILATING CONTRACTORS ASSOCIATION
4 Palace Court London W2 4JG Telephone 020-7229 2488 Fax 020-7727 9268
Orders fo FlY A Publications Old Matlsion House Eamont Bridge Penrith Cumbria CA 10 2BX (Telephone 01768 864771 Fax 01768 86718) Email hvcapoblicationshvwelfarecouk DWn 44 pe ilicatiun for sheet mctal duclwork (Iow- mediulllshy
and high-pressure) 1998) DWIl4 A practical guide to dUGI ork I akage te ting
(revised 2000) DWII54 Specification for plastic~ duct rk DW171 Guide to good Practice for kitchen venlibtion system DW191 Guide to good pracuce glass fibre ductwoJk DwrrMI Acceptance cheme for new products - Redangolar cro
joint classification Guide to good pra tice - Internal cleanliness of new ductwork installations Guide to good practice for the design for the Installation of lire and smoke uampers
J 1Other puhlications
HampV safely guide 5th edition JS2 Tool box talks JS5 Weldlng Safety booklet JSI9 afety facts bo klet Fact sheets 1-24 2nd edition JS2J COSHH manual volume 1 Advice on compliance with the
regulations 1521A CO I-rH manual volume 2 Asses mcnt h ets JS23 Ri k management manual TR3 BrazinltT and bronze welding of copper pipework cUld sheet
(I 976) TR5 Welding of carbon steel pipework (1980)
TR6 Guide to Good Practice for Site Pre sure Testing of Pipework (19 0) Guide to good practice cleanliness of ventilation Ylem
CHARTERED IN TITUTlO OF BUILDING SERVICES E G EERS Delta House 222 Balham High Road London SW12 9BS rTelephone 020-8675 5211 Fax 020-8675 5449) CIBSE Guide Volume A Design Data Volume B In tallatiol1 and quipment Data Volume C Reference Data
CommlssioniJIg Codes These Codes eover the preliminary checkS eUing to work and regulation of vanous catcgories 0 plan The Codes give a guide to design implications Series A Air Distnbution Systems Series B Boiler Plant
ri s C Automatic Conlrol ystems Cr1es R Refrigerating Sy terns
Sene iN Water Distribution Systems
Technkal Memonllda TM 4 Design Notes for the Middle East TM bull Design otes for Ductwork TM 13 Minimi iog lhc Risk of egiounaires Disease
Research Reports RROI95 Ventilation system hygiene - A review of published
infomlatioo on lhe occurrence and ffects of Olltamination Rl~02J95 Air-to-air heal rec v ry RR0395 rnfluen e of HV C on smoke detectors
ATlONAL ENI [ERING SPECIFICATION LfMITED Southgatc hamber 3739 Southgate Street Winchester S023 9EH (Telephone 01962 842058 Fax 01962 R(8982) BUfLDING S RVICES RESEARCH AND [ ORMATION ASSOCIATIO Old Bracknell Lane West Bracknell Berkshire RG 12 4AH (Telephone Brackl1eU (01344) 426511 Fax 01344 487 -7 )
Application Guides AGln4 De tglJing Vana~le Volume middotylans for KOOnl
iir Movement AG1I91 Commissioning of V Sylcms in Buildings 11 6194 Fire Dampers
B) 94 cntiJalion or KitcneTls
AG389 The Commls ionin of Air Systems In Buildmgs AH2192 Commissioning of Bern - A ~ode of Practice TN2417 I Fire Dampec il) Ventilating Ducl
BEATING VENTILATING A AIR CONDITION G MA UFACTURERS ASSOCIATIO (HEVAC) HEVAC Henley Road Medmenham Marlow Buck SU 2ER (Telephone 01491 578674 ox 01491 575024 Emoimiddot infofetacouk)
Publicatjons Air Diffusion Guide Guide to Air Handling Unit Leakage Testing Guide to Good Practice Air Handling Unit Real Room Acoustic ~ st Procedure Specification for the ertiiicatioll ofAir Filters Method of Test for Water Rejection PerfOnTlatce of Louvrcs Subjected 1(1
Simulated Rainfall Test Procedure for Acoustic Loo cs Specification 10 Floor GrilJes - Types Performan e and Method ofTest Specification for the Determination of the Collection Efficiency of SilJ1d
Trap Louvre Domestic Mechwlical Vclltllalion Systems with Heal Recovery Fan Application Guid
~an and Ouctwork Installation Guide Guide to Fan Noise and Vibration
pecification of Requirements for JallJral Smoke and Heal Exhausl Ventilators
pecification for Powered Smoke and Heat Exhaust Ventilators
Specification of Requirements for Smoke Curtains Design Gujue of Smoke Ventilation for Single Storey Lodustrilll Building~
Including those with Mezzanine Floor and IIi Racked Storage Warehou es - Issue 3
Guidance for the Design of Smoke entilation YSlem for Covered and Undergrollnd Car Parks - lssue 1
Application of SOloke Control Equipment and Syst m Guid to Good Practice - Isue J
58
DW154 Sp(C~tiifitiol for Plastics Ductwork
BRITISH STANDARDS INSTIT TION Sales Department 101 P ntooviLle Road London NI 9ND (felephone 020-78 1 78801)
CP 413 1973 Ducts for building ervices
SS 476 Fire tes on building matenals and lruc(ure
Part 4 19 4 Non-combustibility lest or materials
Part 6 I Fire propagation lest for materials
Part 7 1993 Surface spread of tlarnJ tesls for materia
Part 20 1987 Fir resistance of elements of construction
Part 21 1987 Fire r sistlUlce of loadbeanng elements of construction
Part 22 1987 Fhe istallceofllon-loadbearing elemcllts ofconsttuclion Part 23 1987 Contribution of componcnts to the fire resistance 0 a
structure
Part 24t987 Fire resi lance of wl1lilation ductl
SS 5588 nan 919 0 Fire Precautions III thc desIgn and OOSlnJ lion of buildings
S 729 1971 Hot dip galvanized oatiugs (or irOIl aod stcel articles
BS 1449 Steel plate sheet and Irip
Pan 11991 Carbon steel plate heel and strip Part 2 1983 Stainless steel plate sheer and strip
and
B middotENJOI49-2 996 BSEN 10149- 1991)
BSEN 10131 1992
BSEN22063 Sprayed metal coarings 1994 Protection of iron and steel by aluminium and zinc against
atmospheric cOlosion Irotectiotl of iron and ste I against corro ion and oxishydation at elevared temperatures
BS 353 1981 Glossary of lerms relnting to thermal insulation
BS ISO 1479 Self-tapplngscrewsandmetallicdri c crew
B -lSO 7049
1994
B 4800 1989 Painl colour for building purposes B 4848 l0 rolled structural steel sections
Part4 1972 Equal and unequal angles BS 5422 1990 Specification for the use of therm illuating matcriulS
SS 5720 1979 ode of practice for mechanical veutilating and air C 11shy
dirionin bull in building
l3S PR 12814-1 Bend resting for plasric welds
SS PR 12814-2 Tensile testing for plastic welds
SS PR 13067 Appro altesting for plastic welds
BS PR EN I 100-] Vi ual in pection ofplaslic welds
SHEET METAL AND AIR CONDITIONING CONTR-CTORS NATIONAL ASSOCIATION INC (SMACNA) Headquarters 420 I Lafayeue Center Drive Chanlilly Virginia 2051-1209
Mailing Address pa Box 221230 Cbantilly Virginilt120 153-1230
Telephone (703) 803-2980 Fax (703) 803-3732
Accepted IJJdustry Pl3Gtice for Industrial Duct Constnlelion 197 ) i-rchitecmral Sheet kwl Manual ([993)
Comractors Guide lor Modification 10 ooslruerion Colllraets 1993 Ducted Eleclric Heat Guide for ir Handling Ssrerns (1994)
En~rgy ollservatioD Guidelines (1984) Energy Recovery Equipment yslClllS (199l
Fibrou GIns Duct onS1ntClion Standards (1992)
Fire Smoke amp Radiation Damper In tall Guide for HVA Syst ms (1992) Guide t leel Stack 1(95)
HVA Air Duct Leakage Test Manual (19 ) HVA COlllmissioning lvlanual (1994)
H A Duct Construction Standards-Metal amp Flexible (1995) Addendum 01 (Nov 1997)
HVA Duct Systems Inspection Guide (1989)
HVA ySlems-Application (1986) nVAC ByternS-DLlct D ign (1990)
HVi Systems-Testing Adjusting amp Balancing (1993)
indoor Air Quality Manual (1993) tcheu quipment Fabrication Guidelmes (1990)
Managers Guide for elding (1993)
Rectangular Industrial Duct Cons1TUction Standards (19 0) Round Industrial Duct oustmction Standards (1977)
Sei mic Restraint Manual (1991) (wl Appendix E 1993) SMACNA Ma le Index ()fTechnical Publications (1995) Tbennoplnstic Duct CPY ) Construction Manual 1994)
DEPARTME OF THE ENVIRO MENT (Publications Centre) H Stationery Oflice 5 Nine Elms Lane London SWS 5DR
MampEJ 011972 Electrical in tallat1011 in buildings ( ew Editiou)
IampE 0319 Healing hot and cold wat r steam and gas losla1lations for buildings
M amp - No4 1970 Central heating and hot and cold ~ ateT in tallations for
dwelling
M amp ENo100 1971 Mechanical ventilation for building~
ASSOCIATION FOR SPECIALIST FIRE PROTECTlO As ociation House 235 Ash Road AJdershot Hampshire GUl2 4DD
Telephone OJ25221322 Fax 0 J252 333901
lublicalioos Fire Ratcd and moke Outlet Ducrwork An Industry Guide t Design and InSlalla lioll
HEALTH AND SAFETY EXEC TIVE Rose Court 2 Southwark Bridge London SEl 9HS Telephone 020-7717 6000
TWJ THE WELD G TlTUTE Abington Hall Abington Cambridge CB16AL Telepbone 0 J223 89162
Publication DatJ Oil w~ldll1g of lhermopla lics
59
DW154 wciiwlioll for Plastics Ductwork
A -=--DIX
Factors
Specific gravity shy pp = 091 approx UPVC = 14 approx
Some miscellaneous conversion factors
To convert
Length Inches to millimetres Feet to metres
Multiply by
2540 03048
To convert
Millimetres to inches Metres to feet
vIultiply by
003937 3281
Area Square inches to square millimetres 6452 Square millimetres to square inches 000155 Square feet to square metres 00929 Square metres to square feet 10764
Volume Cubic feet to cubic metres Cubic feet to litres Gallons (UK) to litres
002832 2831 4546
Cubic metres to cubic feet Litres to cubic feet Litres to gallons (UK)
35315 00353
022
Mass Ounces to grams Pounds to kiJograms Tons to tonnes
2835 04536
1016
Grams to ounces Kilograms to pounds Tonnes to tons
003527 2205
09842
Volume flow Cubic feet per minute to cubic Cubic metres per second to cubic
metres per second 0000472 feet per minute 2119 Cubic feet per mIDute to litres Litres per second to cubic feet
per second 04719 per minute 2119
Motion Feet per minute to metres per second 000508 Metres per second to feet per minute 197
Pressure Inches water gauge to millibars 2491 Inches wateJ- gauge to pascals (Pa) 2491 I Pa = I ewton per square metre = 10-2 millibars
60
Heating and Ventilating Contractors Association Esca House 34 Palace Court London W2 4JG
Tel 020 7313 4900
e-mail contact Itvcaorguk web site wwwhvcaorguk
Fax 020 7727 9268
DW154 Specificatiol for Plastics Ductwork
STANDARD OMPONENT DRAWINGS - CIRCULAR
FIG
94
DRAW G
I
~ 30deg 090deg
Breeches Piece
DETAILS
95 amp-----~ Blank End
~-----p Multi-Leaf Damper Can be piggolcd or fianged opposed or parallel blade
Alternative controls areshyri=-+- L-T~
I
---
LT~
I r- -
-+1
J HO Hand96
bMD Molori cd
PD Pneumatic
tl-shy bull
Single Bladed Damper 97 ~ saD
on-Return Damper Vertical application only 98 m~D
43
DW154 Sf1tcificatioll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG
99
100
101
102
DRAWING
$ I-
2hr
1 4hr
SD
~v I I
CO TINENTAL COWL
DETAILS
Iris Damper
Fi reS moke Dam persSleeves
2hr Ratillg
With installation frame
4br Rating
Smoke damper
Intumescent Sleeve
Access Openings
Access panel - removable
Access door shy hinged
fnspection cover
Discharge Continental Cowl
44
DW154 Sp(Cii(ltJll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
DRAWINGltIC DETAns
-
I
I
~
I I I High Velocity Discharge Terminal 103 I
I
I I
J I I 1 ~--
Offset Stack Discbarge Terminal 104 1
~ I e --(-
I
N
I
I
I~
I I Vertical Oischarge with Weather Cowl 105 I
--1--1 I
I
GAPI I
RTl AL DISC) lARGE WITH W ATIIER COWL
45
DW154 SpecUicatoll for Plastics Ductwork
STANDARD COMPONE T DRAWINGS - PLA TEQUIPMENTIMISCELLANEOU
FIG DRAWING DETAILS
106 ~~~ Rectangular Attenuator
107 ~- Circular Attenuator
108
~ Beod Attenuator
109 J ~(f) Heating Coil
110 J ftte Cooling Coil
III Jc[ Electric Heating Coil
112 X F
Humidifier
113 [H XX Axial Fan
114 ~fB1famp Noo-standard Ductwork Cross hntchillg (of any separate type) indicates by reference to a key any non DVil54 ductwork system
115 2llIIIIJIIIIIll Flexible Ductwork
46
DW154 SJeCUicll(iol1 for Plastics Ductwork
TABLE 12 - STANDARD ABBREVIAT ONS
ABBREVIATION FLL
AD Acces Door
AFF Axial Flow Fan
AHU Air Handling nit
All Aluminium
AP Acess Panel
AT Attenuator
AV Air enninal Unit
BE 81ank nd
BQ Blast ate Damper
CC Cooling Coil
CF Centrifugal Fan
CTA Cross alk Attenuator
CVU Constant Volume Unit
DP Drain Point
EEC Electric Heating Coil
El Expansion Joint
FAl Fresh Air Inlet
FA From Above
FB From Belo
fBPP Fabric Backed Polypropyl-ne Sheet
Flexle Flexible Connection
lexfD Flexible Du t
C False Ceiling CO an oil Unit
fD Fire Damper
FFL Finished Floor Level
FJ Flanged Joint
FOAM Rigid Polyurethane Self xtinguishing Foam
FOB Flat on Bottom
FOT Flat on Top
GAM Galvanised after ManufacttrJc
GRP Glass Reinforced Plastic
GSS Galvanised Sheet Steel
HC Heating oil
HD and controlled Damper
HH Hand Hole
HL High Level
HVD High Velocity Discharge
IC Inspection Cover
ID lri Damper
IFS Intumescent Fircleevc
47
DW154 Specification for Plastics Ductwork
TABLE 12 - STANDAR ABBREVIATION CONTINUED
ABBREVIATION
IU
L
tv1D
MS
NRD NTS
OBO
OE
PHD
PD
PP
PP
PRD
PVC
RFC
RSC
R
SBO
SO
S1 TST
SSL
TA
TB
TO TJ
TP
TV
TV
OS
UPVC
S
V
VAV
50 RSA
FULL
Induction Unit
Low Level
Motor controlled Damper
Mjld Steel
on Return Damper
at to cale
Opposed Blade Damper
Open End
Parallel Blade Damper
Pneumatic controlled Damper
Polypropylene
Self xtinguishing Polypropylene
Pressure Relief Damper
Polyvinyl Chloride
Rolled Form Chamlel
Rolled Steel Channel
R fUnit
Singl Blade Damper
Smoke Damper
Slip Joint
Stainl t el
tructural Slab Level
To Ab vc
To Blow
Top Down (In Direction of Flow)
Telescopic Joint
Test Point
TU111iog Vane
Top Up (In Direction of Flo )
Voles Otherwise Stated
Unpl3sticisecl Polyvinyl Chloride
Underside
Ultra Violet Light
Variable Air Volume
Rolled Steel Angle (Vith Size)
48
DW154 SJeriiflllioll for Plastics Ductwork
A2 DUCT PRESSUREAPPE DXA Ductwork con truct d to DWIl54 will bebullbullbullbullbullbullbullbullbullbullbullbullbullbull
Air Leakage From Ductwork To be read in conjunction with DW143 A practical guide to Ductwork Leakage Testing
CAUTION As highlighted ill both this docul1lenr and DW14 I lot ellough emphasis can be placed 01 the fact that except for high pressure class C the much more stringent ductwork constructional standard brolght about b the general acceptance of DW154 have irtlally negated the requirement for leakage-testing It is essential lO realise lhat except where it is mandatory this doclllllelll is nOl an endors ~lIlent of the rourine testing of ducts bllt purely a guide to outline the procedures for cononnity with the air leakage limits ill Table l Where the specified methods of assembly and
A3sealing of dlcls are u ed a vi ual inspection wil ordinarily sl~fll e for ver(iatioll of a well engineered and a ceptahfy airtight COl1strucrioll WHERE NOT MANDATORY DUCT LEAKAGE TESTING IS GENERALLY AN UNJUSTIFIED AND SUBSTANTIAL EXPENSE
A1 INTRODUCTION L akage from ducted air distribution systems is an Lmportant consideration in the design and operation of ventilatjon and air conditioning middotystems A ductviork t)ystem tbat ba limited air leakag within defiucd limits wiH cnsUft
that tile design characteristics of the sytem can be maintained It wilJ also ensure that energy and operatLonal cosb are maintained at optimum levels DucLwork constlucted and Ulstalled in accordance with DW154 should minimise a level of air leakage that it) appropriate to tll operating static air pre sur in tile system
A4However it is recouuised that tbe environment in wtJich middotystems are installed is not always conducive to achieving a predictable level of quality in term of system ajr leakage and it is therefore accepted that designer may sometimes require tlle ystem to be tested in part or in total It should be ecogni ed that the testing of duct systems add a ignificant cost to the installation and incur some extra tjm within the programme (Se 47 and 64 re mandatory te-sting)
manufactured to a structural standard that is compatible with the system operating pressure There are three classes of duct con truction to eorre pond with the three pre ure clas meations Class A Lo pressure ducts suita le for a maximum positive operating pressure of 500 Pascal and a maximum negative pressure of -500 Pascals Class B IVledium pressure ductmiddot suitable for a rnaxilnuJJl positive operafjn o pressure of 1000 Pascals and a maxllnum negative pre sure of -750 Pa cal Class C High pre sure ducts suitable for a maximum po ilive operating pressur of 2000 Pa cals and a maximum negativ pres ur of -750 Paltcals
LEAKAGE FROM DUCTWORK Leakao-e front pia tic air ducts occur at the joint~ and is therefore proportional to the total surface area orthe du twork in th system Tb level of leakage i imilarly related to tIle air pres ure in th du t system and whilst there LS n precis formula for calculating the level of air los it i generally accepted that leakage will increase in proportjon to pressure to rbe pOvver of 065 The effect of air leakage from high pressure velocit ductwork is critical tn terms of system perfomlan dege energy consumption and the risk of high frequency noise as ociated with leakage These problems are le critical with medium pressure 10 ity systems but should be con idered Low pres mevelocity ducts present the lowe~t
ri k in tenn of tbe effect of leakage on the operation of the s stern
SYSTEM LEAKAGE LOSS As there i no di ct relatLonship between th volume of air conv yed and the surface area f the ductwork sy tern required to match the building configuratmn it is difficult to express air leakage a a percentage of total air volume Similarly the operating pressure will vary throughollt lh 3 system and a leakage is related to pre me the calculations ar comple However it is generally ac epted tbat in typical good quaJjty systems the leakage from
49
DW154 Specificatioll for Plastics Ductwork
each class of duct llnd r operating condition will be io the region of CIa S A low pressure 6 Clas B medium pres un 3 Clas C high pressure 2
A5 SPECIFYING AIR LEAKAGE TESTING Re peeting both the co -t and programme implications a sociated with te ling du 1 for leakage the designer may for example indicate that a particular system is te ted as follow
a) High pressure ducts - all tested b) Medium pr ssure duets - 10 of the
ductwork shall be s eet d at random and tested
c) Low pre sure - unte ed In any case where a random te t i elected for medium pre sure ductmiddot the followin c1au~e is suggested for inclusion by the de ign r
The designer hall elect at random a maxirnwlI of 10 of the dUCl system to bt tested for air leakage The duct hall be tested af the pressure recommended in Table J3 for the assifi atiol for the ectiol1 of the ductwork that is to be tested The tests shall be carried Ollt as the work proceeds and prior to the application of thermal insulation In the event of test failure of the randomlY selected section the designer shall have The right to select two La1her e tiolls at random for resting Where succes ive failures are identified there shall be a Tight to require rhl COl11raCWr 10 apply remedial attention to the complete ductwork system Th contractor shall provide documented eviden e of the calculalions used to arrive (1
the allowable 10 I for the section to be tested and the client or his agent shall willess and sign the results of the test
able 13 Air leakage rates
Maximum leakage of duct work Static
prcssUft Low-pressure edium-prc-sure I Iigh-prebull me diJfercntial Class A Class B Class C
1 2 J 4 Pa Litres per second per quare metre of surface area 100 054 018 ZOO 084 028 300 110 037 400 132 044 500 153 051 600 058 019 700 064 021 800 069 023 900 075 025
1000 080 027 1100 1200 1300 1400 1500
029 030 032 033 035
1600 1700 1800 1900 2000
036 038 039 040 042
Note Recommend d mean test presures are highlighted iD bold type with the actual selection being left to tll test operator
50
DW154 Sfeeiieaioll for Plastics Ductwork
A9
A10
and air leakage classification for the y em under test
DESIGNERS CALCULATIONS The designer can middotaJculate with reasonable accuracy the predicted total loss from a ystem by
a) Calculating the operatin presure in each ection of the sy tern
b) Calculating the surface area of the ductwork in each correspondin pre lire s ction
c) Calulating the allowabl~ los at the operating pressure for each ection of the system (see table 13 for allowable leakage figures)
VARIABLE PRESSUR S IN SYSTEMS De igner can achieve significant co t saving by matchina operating pressures throughout the system to constmctional standard and appropriate air leakage testing eO the practice of specifying construction tandards for whole duct sy tems based on fan discharge pre sure may incur unnece sary costs on a project For example ome large sy terns ould well be classiC ed for I akage limits as follows
Plant room risers CJas C Main floor distriblltJou CIa B Low pre sure outlets Cla A
A6 SPECIAL CASES There may be ~itLlations on a project where circumstance dictate thal pecial consideration be given to containing air loss s eg a long mn of duclwork may incur a di -proportjonate level of air 10 s In ca es such as thi example the designer can specify an improved tandard of airtighmess ie 80 of alJo~able 10 s for la B Ju ts The designer sbould not specif a CIa C t sI at CIa s C pressure for a CIa s B ducl
A7 SUGG S ED RANGE OF TES ING
A8 TESTING OF PLANT ITEMS Items of inline pJant (eg Fig 106 to 115) will not normaUy be included in an air I akage test The dllctwork contractor may indud such itelllS in tbe te t jf rh quipm ot has a certificate of COnfOlnlity for Ihe pres ure clas
bull High pressure duct bull Medium pre sure ducts bull Low pre sur ducts bull Exposed extract syst ID bull Ceiling void extract
systems bull Secondary ducts from
VAV or fan coil units bull Flexjble duct bull Final connections and
branches to grille and diffusers
100 test See A5 Untested UDt sted
Untested
Untested Untested
Untested
SI
i
DW154 SJecijicafion for Plastics Ductwork
ig 116 Permitted leakage at various pressures
Leakage in litres per second per square metre duct surface area
Vgt
o ltgt 0 ltgt N
ltgt Cgt
0 0 cc
0 0
~
g =
g ~
c 0
J
ltgt 0 I
~ ] tn
ltgt ltgt
In ol
~ 0 ~ 8 ~
~
c ltgt ltgt
~ CJ
~ ~ ~ ~ 8
0shyij
~ ~ ~ t
ltgt ltgt 00
l
~
~ Q
c C
~ rshy
e ltgt
I 1
I Cgt ltgtv
c Co ~
~~ ~ 10
I
0 Cgt
fJshyq 410 ) 1 ltgt
ltgt N
~ shy ltgt ltgt
~ I 1
c
52
DW154 Specificatio for Plastics Ductwork
Example of a completed test sheet Test No
General
Name of job N~ jC43Pt(r2lef Building Repound ~(~~0
Part 1 - Physical details
a Section of duct work to be tested ~(diffPIfff~el1f3rd Floor
b Drawing Number g91~~ c ssure aSSJ L atlOn V~Jl~IRfYgtg~~lPre Cl T Class C
d Test static pressure -(9 raErq~ ~~~~-~~J~~~ ~~ ~~~~ll
Leakaoe factor 9~-tre3$ecMz I OM REFTOTABLE 13)e b bullbullbullbullbullbullbull
f Surface area of duct under test Q~tJJItetre$ CPROMCALCU TIO BELOW)bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull ampampamp bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull
g ]Vlaxi mum permitted leakage -~ (~i~~0 ~~r~~ ~~~l-~-11~ ~~~Q
Part 2 - Test particulars
a Duct static pressure reading 9QFt~q~ ~ middot~~~1 ~~
b Manufacturer and type of liow measuring d vice (-~~~cJ~Y-9Q7EYg c Range of measurement of now measuring device QtP)OQ~(e~~~0I~~~~1~I~ ~~~~~~W~
d Reading of flm measurin o device pmiddot IFROM RIO)ftscag ~
I (DERlVED [ROM CHART SUPPUED WITH RIG US 0 ud)1e Interpreted air flow leakage rate ~(~~~f~~~ (~l~~~~~~~~~~~~~~~~~I
f Duration ~~~~~norn~allY l~ lnil1Ut~~d~~~ it1~ W~ Date of test ~(lITled ut by Wltll s ed by ~ ~
(~lJ MIJLrr) (Si~rrfltJUYJ
Printed Name 1~g0f~ Printed Name ~~Y~9~ and Company 7jl~~~~~( UJd CompanY AB COII$Itallt8
Width and depth or diameter
Periphery ength Area
millimetreS millimetres metre qL1are metre
800 x 750 3100 1755 5440
600 x 650 2500 557 1193
300 x 300 1200 120 144
305 din 958 700 670
250 dia 785 450 353
TOTAL 8000
53
DW154 Specijilarion for Plastics Ductwork
pA XB
Guida ce No es For he ransport Handling and
Storage of uctwork
avoid damage to adjacent duct panels In somc ca es particularly on con acts calling f r repetitive sizes the use of timber jigs and spacers may be justified Where reduced bulk and greater protection are major factor such as consignments for export transporting ductwork in L shape sections may justify the increa ed ite as embly co ts
It is recommended that before a contract is finalised that consideration is given to the subject of site acces material handling and storage as tbcy havgt a strong influence on the cost efficiency of the overall activity of ductwOlk installation
B3 Handling To minilnise th risk of damage duct sections should be clearly identified and deliveries to site should be closely linked to the installation programme so as to avoid accumulation of
B1 Storage and Handling of Ra Material Material should be stored in suitably designed racking out of direct unJight Where possible the e racks should be metal to earth Edges of cut she t may be harp and protective gloves are advised Wearing teel toe-capped boots is recommended Most pIa tic sheet is manufactured with smootb mfaces andor is suppLied with protective coating Care must be taken to prevent accidental lippag of stacked materials Beiuoshy good electrical insulators the movement of stock unless earthed will allow the build up of stati All stock shapes are chemically stable at normal temperature Whil t some raw materials used in their manufacture may themselves pre ent a toxic hazard once incorporated into the lOck bape they no long r constitute such a hazard and no dermatitic bazard are known nor are any
unfiJied ductwork and minimise double handling It is important to recognise that ductwork panels joint and corners arc susceptible to damage and care must be taken wheu band ling such material through a site During handling individual item of duct work may be liable to light cross sectional deformation until thev become an integral pan of a completed ductwork system Whilst this may temporarily detract from its intended appearance thi deformation will not have any detrimental effect on the functionality of the finally a semblecl system Installation of duct work and asociated plant items ill illevitably involve manual handUng The responsibi Iiry of employers and employees to a ses the risk of personal injury during mallual handling operations is et out in the HS E publication L23 Guidance on Manual Handling Regulations 1992
environmental problems expected 84 Site storage
B2 fransport Large capacity vehicles with high-sided open or closed-top bodies are tlle mo t suitable for the transport of dllctwork Careful consideration should be given to the
Adequate floor space IDust be provided within tbe building for the site storage of ductvork Such storage shalt make due allowance for thc stOf(ne of ductwork in stacks such that access ~ egt
between them is of sufficient width to pennil the removal of item without interference to
unloading of transport on sit a not all siJes b n fit from the material handlino- and access facilities that exi [ in a manufacturing workshop such as crane- fork-lifts or loading bay Site handJiog facilities along with
adjoining sta ks Ductvork components should be positioned so a to avoid crushing Ductwork of small panel size may be stored horizontally however care should be exercised to ensure that tack sizes are limited 10 within
ehicular acce s restrictions may itilluence the type and ize of transport to be uWised
engtlls of ductwork should be positioned 0
the tmctural strength of the duct sections to prevent distortion of the lower sections within the stack
as to avoid crushing Lengths Witll projections such as branches and bends i1anges girths damper quadrauL should be loaded so as to
54
DW154 S1tciic(ltioll for Plastics Ductwork
85 Internal cleanliness of new ductwork The site storage of ductwork introduces the important cODsideration of maintaining the internal cleanliness of the ductwork R feren e should be made to HVCA documentshybull DWffM2 Guide to Good Practice - internal
Cleanliness of New Ductwork Installations If the above conditioDs can not be satisfied consideration should be given by tJle designer to amending the specification to include for Po t Installation Cleaning as covered by tJ1C HVCA documentshybull TRJ17 Guide to Good Practic - Cleanliness
of Ventilation Systems
APPE DIXC
Fi e Retardant inishes C1 Improvement in the fire retardancy of plastic
ducts can be achieved to varying degrees and is wholly dependent llPOll the surface coating laminating resin selected and construction specification adopted In some instances smoke emission is coILSidered equaUy with other speci fication requirernen ts of the materials resistance to ignition and bumjng It is therefore important for design rs to establ ish the clients and officers detailed requirements and not rely on a tbird party interpretation of fire resisting or fire retardant Where possible the specification should refer dir etly to compliance with a British or European Standard identifying the specific sections applicable There are various types of resin and mat rcLnforcements that can achieve a Class 1 surface spread of flame ratin o when tested according to BS476 Part 7 (1987) This test puts materials illto Class I - 4 in descending order of perfoDllance according to the rat and extent of flame spread over their surfac under standard beating conditions Materials should also be tested for flre propagarion to BS476 Part 6 (1989) Tbi tesr measures the amount and rate of heat evolved by the material when subjected to standard heating
conditions Test results are given as an index of Perfonnance (i) whicb is based on three sub indices (iJ (i1) (h) The higher the value of the Index of Performance (i) the greater is the material s contribution to fire growth The higher the value of the sub-index 0) rhe greater the ease of ignition aod flame spread The highest product performance classification as defined in Approved Document B of the Building Regulations is Class O This is acLlieved if a material surface of a composite ploduct i~ either a) composed throughout of materials of
limited combustibility or b) a Class I material which has a tlre
propagation index (i) of not more than 12 and sub-index (i l ) of nor more than 6
01 J Class 0 is not a cla$sif1cation identified in any British Standard test
There are resin system reported to be classified to Class O when tested to BS476 Pcl1S 6 and 7 however designers need to ensure that such sysrems can be applied to their proposed design In propriety resinmat system available the fabrication techniques and COITect application are critical to the integrity of the reinforcing and clas ificatiol1 For example in some systems the u e of a non-fire retardant gelcont on a fire retardant substrate would reduce the classification For further information see HVCA publication DW144 Appendix D
55
DW154 SplCijiClIliol1 for Plastics Ductwork
x Guidance otes For nspectmiddoton Servicing a d
Clean-ng Access Openings
D1 GE ERAL This appendix highlight in ummary fOI111
the acce considerations that hould be made by the design r iD terms of inspection servicing and cleaning Having considered the seop and the design of the dUCI work system relative to the guidelines outlined below the designer should clearly indicate which levels of acces should be incorporated into the manufacture of a new duct work system (See Table 14 and Note I b low it
D2 DESIGN CONSIDERATIONS
D21 In ptction and servicing requireshyments are set out in Section 15 of Lhis specification
D22 Cleaning requirements are set out in the HVCA pubUcation TRl7 Guide to Good Practice Clean Lines of Ventilation Systems and the guide tates The precise location ize and
type of access would be dependent on the type of ductwork cleaning inspection and te ting metbods to b adopted Care protection and standards of cleanliness prior LO cOlllmisionin o
are set out in th AV A publication DWITM2 Guide to Good Practice Internal Cleanliness of New Ductwork Installations and th guide state Wh re specific limits of cleanliness are required ductwork sball be cleaned after installation by a spcialist cleaning contractor It will b in the interests of tht desioner botb financially and practically to cunsider employing a specialist c1eauing contractor at tbe
outset of a contract to internally clean newly installed ductwork prior to bandover This approach would reali e the following benefit shyi) Tb actual numb r of cleaning
access panels could be detennined to suit the method of cleaning to be adopted (This may be 1 s than the maximum requiremen listed under Lev 13 of Table 14)
ii) Clear directions could b given to the ductwork contractor as to tJle size and location of cleaning access panels that are required to be fitted during the mauushyfaclunng pro s
iii) The specialist cleaning operation prior to commi ioning vould enable the cleaning contractor to verify the practical acee requirement for the future cleaning operation associated -vitb a regular maintenance programme
iv) A specialist cleaning operation prior to commissioning would allow the designer to omit from the speeilicatiolJ the DWrrM2 requirem nt for factory sealing protection wipe downs and capping-off
v) Specialist Ieall ill 0 to the measurable standard defin d in TR17 will allow an objective definition of cleanline to be achieved
Car ful consideration must be gIven by the designer to the practl aJ problems associated witb the manufacture and fitting of suitably si Led access panel on small cross section duct and on the circular faces of rouod and flat oval ducts in particular
D23 Special con ideration must be given by the de igner to the practical problems associated with gaining personnel access to heavily congested ceiling areas and multi-la red du twork systems This approach would avoid
56
DW154 Spfciication for Plastics Ductwork
the possibility of access panels being D3 ACCESS 0 IN-LINE EQUIPMENT incorporated into a ductwork system at the This appendix unly covers acc il1spection manufacturing stage that were later found in through the ductwork body adjacent to an item practice to be inaccessible for either ervicing of in-line equipment and not openings in the or cleaning activities equipment itself
able 14 Acce requirements for inspection servicing and cleaning
HVCA PUBLICATIO REFE NeE (uidtgt 10 Gund Prartict
Adjace t OW144 Cleanliness orVcnlillltio S~lcr~ fRjJ7
in-line LeyeJ 1 Level 2 Level 3 ite sequipment pcdionSen lcin~ Section d C1eaniJl( SUn(O)lnspc lion Palle ltk~m_n
2011 (minimum OiL Jubje-ct to duct ~zel (ft~ -Panels
Control Da pcrs One (inspection) 203 One 300 mm x 200 mm Both sid Fire Dampers One (sCTjdJl~) 20211 One 300 0101 x 200 mm One side HeatingCooling Coils One (inspedion) 20213 One 300 mm x 200 mm (lIpstream) Both sides Attenuators (rectangular) None required One 300 mm x 200 mm (downstream) Both sides Attenuators (circular) one retluired One 300 mm x 200 mm (downstream) One side Filter Sections One (inspection) 20212 one required Uoth sides Air Turn Vanes None requjred None required Both sides Changes of Direction None required one required One side In-Duct FansDevices One (inspection) 20213 None required Both sides l
1 In the absence of any indication by the designer only Level ) access will be jncorporated into a new ductwork system
2 Tbe panel izes associated with Lev lis I and 3 acee s ar e middottablished by reference to Section 20 of DW144 and Section 2 ofTRll7 respectively
57
DW154 Speclfifatio for Plastics Ductwork
pA XE
B-bliography Included in this Bibliography are technical pUblications which may be of interest (0 ductwork designers fabricators and erectors and to tho e in the heating ventilatlng air conditioning industries generally nquiric should be made of the relevant organisation at the address quoted Since its publication other addresse contained within 0V154 mav have changed and some pubJicalions may have been superseded
HEATING AND VENTILATING CONTRACTORS ASSOCIATION
4 Palace Court London W2 4JG Telephone 020-7229 2488 Fax 020-7727 9268
Orders fo FlY A Publications Old Matlsion House Eamont Bridge Penrith Cumbria CA 10 2BX (Telephone 01768 864771 Fax 01768 86718) Email hvcapoblicationshvwelfarecouk DWn 44 pe ilicatiun for sheet mctal duclwork (Iow- mediulllshy
and high-pressure) 1998) DWIl4 A practical guide to dUGI ork I akage te ting
(revised 2000) DWII54 Specification for plastic~ duct rk DW171 Guide to good Practice for kitchen venlibtion system DW191 Guide to good pracuce glass fibre ductwoJk DwrrMI Acceptance cheme for new products - Redangolar cro
joint classification Guide to good pra tice - Internal cleanliness of new ductwork installations Guide to good practice for the design for the Installation of lire and smoke uampers
J 1Other puhlications
HampV safely guide 5th edition JS2 Tool box talks JS5 Weldlng Safety booklet JSI9 afety facts bo klet Fact sheets 1-24 2nd edition JS2J COSHH manual volume 1 Advice on compliance with the
regulations 1521A CO I-rH manual volume 2 Asses mcnt h ets JS23 Ri k management manual TR3 BrazinltT and bronze welding of copper pipework cUld sheet
(I 976) TR5 Welding of carbon steel pipework (1980)
TR6 Guide to Good Practice for Site Pre sure Testing of Pipework (19 0) Guide to good practice cleanliness of ventilation Ylem
CHARTERED IN TITUTlO OF BUILDING SERVICES E G EERS Delta House 222 Balham High Road London SW12 9BS rTelephone 020-8675 5211 Fax 020-8675 5449) CIBSE Guide Volume A Design Data Volume B In tallatiol1 and quipment Data Volume C Reference Data
CommlssioniJIg Codes These Codes eover the preliminary checkS eUing to work and regulation of vanous catcgories 0 plan The Codes give a guide to design implications Series A Air Distnbution Systems Series B Boiler Plant
ri s C Automatic Conlrol ystems Cr1es R Refrigerating Sy terns
Sene iN Water Distribution Systems
Technkal Memonllda TM 4 Design Notes for the Middle East TM bull Design otes for Ductwork TM 13 Minimi iog lhc Risk of egiounaires Disease
Research Reports RROI95 Ventilation system hygiene - A review of published
infomlatioo on lhe occurrence and ffects of Olltamination Rl~02J95 Air-to-air heal rec v ry RR0395 rnfluen e of HV C on smoke detectors
ATlONAL ENI [ERING SPECIFICATION LfMITED Southgatc hamber 3739 Southgate Street Winchester S023 9EH (Telephone 01962 842058 Fax 01962 R(8982) BUfLDING S RVICES RESEARCH AND [ ORMATION ASSOCIATIO Old Bracknell Lane West Bracknell Berkshire RG 12 4AH (Telephone Brackl1eU (01344) 426511 Fax 01344 487 -7 )
Application Guides AGln4 De tglJing Vana~le Volume middotylans for KOOnl
iir Movement AG1I91 Commissioning of V Sylcms in Buildings 11 6194 Fire Dampers
B) 94 cntiJalion or KitcneTls
AG389 The Commls ionin of Air Systems In Buildmgs AH2192 Commissioning of Bern - A ~ode of Practice TN2417 I Fire Dampec il) Ventilating Ducl
BEATING VENTILATING A AIR CONDITION G MA UFACTURERS ASSOCIATIO (HEVAC) HEVAC Henley Road Medmenham Marlow Buck SU 2ER (Telephone 01491 578674 ox 01491 575024 Emoimiddot infofetacouk)
Publicatjons Air Diffusion Guide Guide to Air Handling Unit Leakage Testing Guide to Good Practice Air Handling Unit Real Room Acoustic ~ st Procedure Specification for the ertiiicatioll ofAir Filters Method of Test for Water Rejection PerfOnTlatce of Louvrcs Subjected 1(1
Simulated Rainfall Test Procedure for Acoustic Loo cs Specification 10 Floor GrilJes - Types Performan e and Method ofTest Specification for the Determination of the Collection Efficiency of SilJ1d
Trap Louvre Domestic Mechwlical Vclltllalion Systems with Heal Recovery Fan Application Guid
~an and Ouctwork Installation Guide Guide to Fan Noise and Vibration
pecification of Requirements for JallJral Smoke and Heal Exhausl Ventilators
pecification for Powered Smoke and Heat Exhaust Ventilators
Specification of Requirements for Smoke Curtains Design Gujue of Smoke Ventilation for Single Storey Lodustrilll Building~
Including those with Mezzanine Floor and IIi Racked Storage Warehou es - Issue 3
Guidance for the Design of Smoke entilation YSlem for Covered and Undergrollnd Car Parks - lssue 1
Application of SOloke Control Equipment and Syst m Guid to Good Practice - Isue J
58
DW154 Sp(C~tiifitiol for Plastics Ductwork
BRITISH STANDARDS INSTIT TION Sales Department 101 P ntooviLle Road London NI 9ND (felephone 020-78 1 78801)
CP 413 1973 Ducts for building ervices
SS 476 Fire tes on building matenals and lruc(ure
Part 4 19 4 Non-combustibility lest or materials
Part 6 I Fire propagation lest for materials
Part 7 1993 Surface spread of tlarnJ tesls for materia
Part 20 1987 Fir resistance of elements of construction
Part 21 1987 Fire r sistlUlce of loadbeanng elements of construction
Part 22 1987 Fhe istallceofllon-loadbearing elemcllts ofconsttuclion Part 23 1987 Contribution of componcnts to the fire resistance 0 a
structure
Part 24t987 Fire resi lance of wl1lilation ductl
SS 5588 nan 919 0 Fire Precautions III thc desIgn and OOSlnJ lion of buildings
S 729 1971 Hot dip galvanized oatiugs (or irOIl aod stcel articles
BS 1449 Steel plate sheet and Irip
Pan 11991 Carbon steel plate heel and strip Part 2 1983 Stainless steel plate sheer and strip
and
B middotENJOI49-2 996 BSEN 10149- 1991)
BSEN 10131 1992
BSEN22063 Sprayed metal coarings 1994 Protection of iron and steel by aluminium and zinc against
atmospheric cOlosion Irotectiotl of iron and ste I against corro ion and oxishydation at elevared temperatures
BS 353 1981 Glossary of lerms relnting to thermal insulation
BS ISO 1479 Self-tapplngscrewsandmetallicdri c crew
B -lSO 7049
1994
B 4800 1989 Painl colour for building purposes B 4848 l0 rolled structural steel sections
Part4 1972 Equal and unequal angles BS 5422 1990 Specification for the use of therm illuating matcriulS
SS 5720 1979 ode of practice for mechanical veutilating and air C 11shy
dirionin bull in building
l3S PR 12814-1 Bend resting for plasric welds
SS PR 12814-2 Tensile testing for plastic welds
SS PR 13067 Appro altesting for plastic welds
BS PR EN I 100-] Vi ual in pection ofplaslic welds
SHEET METAL AND AIR CONDITIONING CONTR-CTORS NATIONAL ASSOCIATION INC (SMACNA) Headquarters 420 I Lafayeue Center Drive Chanlilly Virginia 2051-1209
Mailing Address pa Box 221230 Cbantilly Virginilt120 153-1230
Telephone (703) 803-2980 Fax (703) 803-3732
Accepted IJJdustry Pl3Gtice for Industrial Duct Constnlelion 197 ) i-rchitecmral Sheet kwl Manual ([993)
Comractors Guide lor Modification 10 ooslruerion Colllraets 1993 Ducted Eleclric Heat Guide for ir Handling Ssrerns (1994)
En~rgy ollservatioD Guidelines (1984) Energy Recovery Equipment yslClllS (199l
Fibrou GIns Duct onS1ntClion Standards (1992)
Fire Smoke amp Radiation Damper In tall Guide for HVA Syst ms (1992) Guide t leel Stack 1(95)
HVA Air Duct Leakage Test Manual (19 ) HVA COlllmissioning lvlanual (1994)
H A Duct Construction Standards-Metal amp Flexible (1995) Addendum 01 (Nov 1997)
HVA Duct Systems Inspection Guide (1989)
HVA ySlems-Application (1986) nVAC ByternS-DLlct D ign (1990)
HVi Systems-Testing Adjusting amp Balancing (1993)
indoor Air Quality Manual (1993) tcheu quipment Fabrication Guidelmes (1990)
Managers Guide for elding (1993)
Rectangular Industrial Duct Cons1TUction Standards (19 0) Round Industrial Duct oustmction Standards (1977)
Sei mic Restraint Manual (1991) (wl Appendix E 1993) SMACNA Ma le Index ()fTechnical Publications (1995) Tbennoplnstic Duct CPY ) Construction Manual 1994)
DEPARTME OF THE ENVIRO MENT (Publications Centre) H Stationery Oflice 5 Nine Elms Lane London SWS 5DR
MampEJ 011972 Electrical in tallat1011 in buildings ( ew Editiou)
IampE 0319 Healing hot and cold wat r steam and gas losla1lations for buildings
M amp - No4 1970 Central heating and hot and cold ~ ateT in tallations for
dwelling
M amp ENo100 1971 Mechanical ventilation for building~
ASSOCIATION FOR SPECIALIST FIRE PROTECTlO As ociation House 235 Ash Road AJdershot Hampshire GUl2 4DD
Telephone OJ25221322 Fax 0 J252 333901
lublicalioos Fire Ratcd and moke Outlet Ducrwork An Industry Guide t Design and InSlalla lioll
HEALTH AND SAFETY EXEC TIVE Rose Court 2 Southwark Bridge London SEl 9HS Telephone 020-7717 6000
TWJ THE WELD G TlTUTE Abington Hall Abington Cambridge CB16AL Telepbone 0 J223 89162
Publication DatJ Oil w~ldll1g of lhermopla lics
59
DW154 wciiwlioll for Plastics Ductwork
A -=--DIX
Factors
Specific gravity shy pp = 091 approx UPVC = 14 approx
Some miscellaneous conversion factors
To convert
Length Inches to millimetres Feet to metres
Multiply by
2540 03048
To convert
Millimetres to inches Metres to feet
vIultiply by
003937 3281
Area Square inches to square millimetres 6452 Square millimetres to square inches 000155 Square feet to square metres 00929 Square metres to square feet 10764
Volume Cubic feet to cubic metres Cubic feet to litres Gallons (UK) to litres
002832 2831 4546
Cubic metres to cubic feet Litres to cubic feet Litres to gallons (UK)
35315 00353
022
Mass Ounces to grams Pounds to kiJograms Tons to tonnes
2835 04536
1016
Grams to ounces Kilograms to pounds Tonnes to tons
003527 2205
09842
Volume flow Cubic feet per minute to cubic Cubic metres per second to cubic
metres per second 0000472 feet per minute 2119 Cubic feet per mIDute to litres Litres per second to cubic feet
per second 04719 per minute 2119
Motion Feet per minute to metres per second 000508 Metres per second to feet per minute 197
Pressure Inches water gauge to millibars 2491 Inches wateJ- gauge to pascals (Pa) 2491 I Pa = I ewton per square metre = 10-2 millibars
60
Heating and Ventilating Contractors Association Esca House 34 Palace Court London W2 4JG
Tel 020 7313 4900
e-mail contact Itvcaorguk web site wwwhvcaorguk
Fax 020 7727 9268
DW154 Sf1tcificatioll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
FIG
99
100
101
102
DRAWING
$ I-
2hr
1 4hr
SD
~v I I
CO TINENTAL COWL
DETAILS
Iris Damper
Fi reS moke Dam persSleeves
2hr Ratillg
With installation frame
4br Rating
Smoke damper
Intumescent Sleeve
Access Openings
Access panel - removable
Access door shy hinged
fnspection cover
Discharge Continental Cowl
44
DW154 Sp(Cii(ltJll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
DRAWINGltIC DETAns
-
I
I
~
I I I High Velocity Discharge Terminal 103 I
I
I I
J I I 1 ~--
Offset Stack Discbarge Terminal 104 1
~ I e --(-
I
N
I
I
I~
I I Vertical Oischarge with Weather Cowl 105 I
--1--1 I
I
GAPI I
RTl AL DISC) lARGE WITH W ATIIER COWL
45
DW154 SpecUicatoll for Plastics Ductwork
STANDARD COMPONE T DRAWINGS - PLA TEQUIPMENTIMISCELLANEOU
FIG DRAWING DETAILS
106 ~~~ Rectangular Attenuator
107 ~- Circular Attenuator
108
~ Beod Attenuator
109 J ~(f) Heating Coil
110 J ftte Cooling Coil
III Jc[ Electric Heating Coil
112 X F
Humidifier
113 [H XX Axial Fan
114 ~fB1famp Noo-standard Ductwork Cross hntchillg (of any separate type) indicates by reference to a key any non DVil54 ductwork system
115 2llIIIIJIIIIIll Flexible Ductwork
46
DW154 SJeCUicll(iol1 for Plastics Ductwork
TABLE 12 - STANDARD ABBREVIAT ONS
ABBREVIATION FLL
AD Acces Door
AFF Axial Flow Fan
AHU Air Handling nit
All Aluminium
AP Acess Panel
AT Attenuator
AV Air enninal Unit
BE 81ank nd
BQ Blast ate Damper
CC Cooling Coil
CF Centrifugal Fan
CTA Cross alk Attenuator
CVU Constant Volume Unit
DP Drain Point
EEC Electric Heating Coil
El Expansion Joint
FAl Fresh Air Inlet
FA From Above
FB From Belo
fBPP Fabric Backed Polypropyl-ne Sheet
Flexle Flexible Connection
lexfD Flexible Du t
C False Ceiling CO an oil Unit
fD Fire Damper
FFL Finished Floor Level
FJ Flanged Joint
FOAM Rigid Polyurethane Self xtinguishing Foam
FOB Flat on Bottom
FOT Flat on Top
GAM Galvanised after ManufacttrJc
GRP Glass Reinforced Plastic
GSS Galvanised Sheet Steel
HC Heating oil
HD and controlled Damper
HH Hand Hole
HL High Level
HVD High Velocity Discharge
IC Inspection Cover
ID lri Damper
IFS Intumescent Fircleevc
47
DW154 Specification for Plastics Ductwork
TABLE 12 - STANDAR ABBREVIATION CONTINUED
ABBREVIATION
IU
L
tv1D
MS
NRD NTS
OBO
OE
PHD
PD
PP
PP
PRD
PVC
RFC
RSC
R
SBO
SO
S1 TST
SSL
TA
TB
TO TJ
TP
TV
TV
OS
UPVC
S
V
VAV
50 RSA
FULL
Induction Unit
Low Level
Motor controlled Damper
Mjld Steel
on Return Damper
at to cale
Opposed Blade Damper
Open End
Parallel Blade Damper
Pneumatic controlled Damper
Polypropylene
Self xtinguishing Polypropylene
Pressure Relief Damper
Polyvinyl Chloride
Rolled Form Chamlel
Rolled Steel Channel
R fUnit
Singl Blade Damper
Smoke Damper
Slip Joint
Stainl t el
tructural Slab Level
To Ab vc
To Blow
Top Down (In Direction of Flow)
Telescopic Joint
Test Point
TU111iog Vane
Top Up (In Direction of Flo )
Voles Otherwise Stated
Unpl3sticisecl Polyvinyl Chloride
Underside
Ultra Violet Light
Variable Air Volume
Rolled Steel Angle (Vith Size)
48
DW154 SJeriiflllioll for Plastics Ductwork
A2 DUCT PRESSUREAPPE DXA Ductwork con truct d to DWIl54 will bebullbullbullbullbullbullbullbullbullbullbullbullbullbull
Air Leakage From Ductwork To be read in conjunction with DW143 A practical guide to Ductwork Leakage Testing
CAUTION As highlighted ill both this docul1lenr and DW14 I lot ellough emphasis can be placed 01 the fact that except for high pressure class C the much more stringent ductwork constructional standard brolght about b the general acceptance of DW154 have irtlally negated the requirement for leakage-testing It is essential lO realise lhat except where it is mandatory this doclllllelll is nOl an endors ~lIlent of the rourine testing of ducts bllt purely a guide to outline the procedures for cononnity with the air leakage limits ill Table l Where the specified methods of assembly and
A3sealing of dlcls are u ed a vi ual inspection wil ordinarily sl~fll e for ver(iatioll of a well engineered and a ceptahfy airtight COl1strucrioll WHERE NOT MANDATORY DUCT LEAKAGE TESTING IS GENERALLY AN UNJUSTIFIED AND SUBSTANTIAL EXPENSE
A1 INTRODUCTION L akage from ducted air distribution systems is an Lmportant consideration in the design and operation of ventilatjon and air conditioning middotystems A ductviork t)ystem tbat ba limited air leakag within defiucd limits wiH cnsUft
that tile design characteristics of the sytem can be maintained It wilJ also ensure that energy and operatLonal cosb are maintained at optimum levels DucLwork constlucted and Ulstalled in accordance with DW154 should minimise a level of air leakage that it) appropriate to tll operating static air pre sur in tile system
A4However it is recouuised that tbe environment in wtJich middotystems are installed is not always conducive to achieving a predictable level of quality in term of system ajr leakage and it is therefore accepted that designer may sometimes require tlle ystem to be tested in part or in total It should be ecogni ed that the testing of duct systems add a ignificant cost to the installation and incur some extra tjm within the programme (Se 47 and 64 re mandatory te-sting)
manufactured to a structural standard that is compatible with the system operating pressure There are three classes of duct con truction to eorre pond with the three pre ure clas meations Class A Lo pressure ducts suita le for a maximum positive operating pressure of 500 Pascal and a maximum negative pressure of -500 Pascals Class B IVledium pressure ductmiddot suitable for a rnaxilnuJJl positive operafjn o pressure of 1000 Pascals and a maxllnum negative pre sure of -750 Pa cal Class C High pre sure ducts suitable for a maximum po ilive operating pressur of 2000 Pa cals and a maximum negativ pres ur of -750 Paltcals
LEAKAGE FROM DUCTWORK Leakao-e front pia tic air ducts occur at the joint~ and is therefore proportional to the total surface area orthe du twork in th system Tb level of leakage i imilarly related to tIle air pres ure in th du t system and whilst there LS n precis formula for calculating the level of air los it i generally accepted that leakage will increase in proportjon to pressure to rbe pOvver of 065 The effect of air leakage from high pressure velocit ductwork is critical tn terms of system perfomlan dege energy consumption and the risk of high frequency noise as ociated with leakage These problems are le critical with medium pressure 10 ity systems but should be con idered Low pres mevelocity ducts present the lowe~t
ri k in tenn of tbe effect of leakage on the operation of the s stern
SYSTEM LEAKAGE LOSS As there i no di ct relatLonship between th volume of air conv yed and the surface area f the ductwork sy tern required to match the building configuratmn it is difficult to express air leakage a a percentage of total air volume Similarly the operating pressure will vary throughollt lh 3 system and a leakage is related to pre me the calculations ar comple However it is generally ac epted tbat in typical good quaJjty systems the leakage from
49
DW154 Specificatioll for Plastics Ductwork
each class of duct llnd r operating condition will be io the region of CIa S A low pressure 6 Clas B medium pres un 3 Clas C high pressure 2
A5 SPECIFYING AIR LEAKAGE TESTING Re peeting both the co -t and programme implications a sociated with te ling du 1 for leakage the designer may for example indicate that a particular system is te ted as follow
a) High pressure ducts - all tested b) Medium pr ssure duets - 10 of the
ductwork shall be s eet d at random and tested
c) Low pre sure - unte ed In any case where a random te t i elected for medium pre sure ductmiddot the followin c1au~e is suggested for inclusion by the de ign r
The designer hall elect at random a maxirnwlI of 10 of the dUCl system to bt tested for air leakage The duct hall be tested af the pressure recommended in Table J3 for the assifi atiol for the ectiol1 of the ductwork that is to be tested The tests shall be carried Ollt as the work proceeds and prior to the application of thermal insulation In the event of test failure of the randomlY selected section the designer shall have The right to select two La1her e tiolls at random for resting Where succes ive failures are identified there shall be a Tight to require rhl COl11raCWr 10 apply remedial attention to the complete ductwork system Th contractor shall provide documented eviden e of the calculalions used to arrive (1
the allowable 10 I for the section to be tested and the client or his agent shall willess and sign the results of the test
able 13 Air leakage rates
Maximum leakage of duct work Static
prcssUft Low-pressure edium-prc-sure I Iigh-prebull me diJfercntial Class A Class B Class C
1 2 J 4 Pa Litres per second per quare metre of surface area 100 054 018 ZOO 084 028 300 110 037 400 132 044 500 153 051 600 058 019 700 064 021 800 069 023 900 075 025
1000 080 027 1100 1200 1300 1400 1500
029 030 032 033 035
1600 1700 1800 1900 2000
036 038 039 040 042
Note Recommend d mean test presures are highlighted iD bold type with the actual selection being left to tll test operator
50
DW154 Sfeeiieaioll for Plastics Ductwork
A9
A10
and air leakage classification for the y em under test
DESIGNERS CALCULATIONS The designer can middotaJculate with reasonable accuracy the predicted total loss from a ystem by
a) Calculating the operatin presure in each ection of the sy tern
b) Calculating the surface area of the ductwork in each correspondin pre lire s ction
c) Calulating the allowabl~ los at the operating pressure for each ection of the system (see table 13 for allowable leakage figures)
VARIABLE PRESSUR S IN SYSTEMS De igner can achieve significant co t saving by matchina operating pressures throughout the system to constmctional standard and appropriate air leakage testing eO the practice of specifying construction tandards for whole duct sy tems based on fan discharge pre sure may incur unnece sary costs on a project For example ome large sy terns ould well be classiC ed for I akage limits as follows
Plant room risers CJas C Main floor distriblltJou CIa B Low pre sure outlets Cla A
A6 SPECIAL CASES There may be ~itLlations on a project where circumstance dictate thal pecial consideration be given to containing air loss s eg a long mn of duclwork may incur a di -proportjonate level of air 10 s In ca es such as thi example the designer can specify an improved tandard of airtighmess ie 80 of alJo~able 10 s for la B Ju ts The designer sbould not specif a CIa C t sI at CIa s C pressure for a CIa s B ducl
A7 SUGG S ED RANGE OF TES ING
A8 TESTING OF PLANT ITEMS Items of inline pJant (eg Fig 106 to 115) will not normaUy be included in an air I akage test The dllctwork contractor may indud such itelllS in tbe te t jf rh quipm ot has a certificate of COnfOlnlity for Ihe pres ure clas
bull High pressure duct bull Medium pre sure ducts bull Low pre sur ducts bull Exposed extract syst ID bull Ceiling void extract
systems bull Secondary ducts from
VAV or fan coil units bull Flexjble duct bull Final connections and
branches to grille and diffusers
100 test See A5 Untested UDt sted
Untested
Untested Untested
Untested
SI
i
DW154 SJecijicafion for Plastics Ductwork
ig 116 Permitted leakage at various pressures
Leakage in litres per second per square metre duct surface area
Vgt
o ltgt 0 ltgt N
ltgt Cgt
0 0 cc
0 0
~
g =
g ~
c 0
J
ltgt 0 I
~ ] tn
ltgt ltgt
In ol
~ 0 ~ 8 ~
~
c ltgt ltgt
~ CJ
~ ~ ~ ~ 8
0shyij
~ ~ ~ t
ltgt ltgt 00
l
~
~ Q
c C
~ rshy
e ltgt
I 1
I Cgt ltgtv
c Co ~
~~ ~ 10
I
0 Cgt
fJshyq 410 ) 1 ltgt
ltgt N
~ shy ltgt ltgt
~ I 1
c
52
DW154 Specificatio for Plastics Ductwork
Example of a completed test sheet Test No
General
Name of job N~ jC43Pt(r2lef Building Repound ~(~~0
Part 1 - Physical details
a Section of duct work to be tested ~(diffPIfff~el1f3rd Floor
b Drawing Number g91~~ c ssure aSSJ L atlOn V~Jl~IRfYgtg~~lPre Cl T Class C
d Test static pressure -(9 raErq~ ~~~~-~~J~~~ ~~ ~~~~ll
Leakaoe factor 9~-tre3$ecMz I OM REFTOTABLE 13)e b bullbullbullbullbullbullbull
f Surface area of duct under test Q~tJJItetre$ CPROMCALCU TIO BELOW)bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull ampampamp bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull
g ]Vlaxi mum permitted leakage -~ (~i~~0 ~~r~~ ~~~l-~-11~ ~~~Q
Part 2 - Test particulars
a Duct static pressure reading 9QFt~q~ ~ middot~~~1 ~~
b Manufacturer and type of liow measuring d vice (-~~~cJ~Y-9Q7EYg c Range of measurement of now measuring device QtP)OQ~(e~~~0I~~~~1~I~ ~~~~~~W~
d Reading of flm measurin o device pmiddot IFROM RIO)ftscag ~
I (DERlVED [ROM CHART SUPPUED WITH RIG US 0 ud)1e Interpreted air flow leakage rate ~(~~~f~~~ (~l~~~~~~~~~~~~~~~~~I
f Duration ~~~~~norn~allY l~ lnil1Ut~~d~~~ it1~ W~ Date of test ~(lITled ut by Wltll s ed by ~ ~
(~lJ MIJLrr) (Si~rrfltJUYJ
Printed Name 1~g0f~ Printed Name ~~Y~9~ and Company 7jl~~~~~( UJd CompanY AB COII$Itallt8
Width and depth or diameter
Periphery ength Area
millimetreS millimetres metre qL1are metre
800 x 750 3100 1755 5440
600 x 650 2500 557 1193
300 x 300 1200 120 144
305 din 958 700 670
250 dia 785 450 353
TOTAL 8000
53
DW154 Specijilarion for Plastics Ductwork
pA XB
Guida ce No es For he ransport Handling and
Storage of uctwork
avoid damage to adjacent duct panels In somc ca es particularly on con acts calling f r repetitive sizes the use of timber jigs and spacers may be justified Where reduced bulk and greater protection are major factor such as consignments for export transporting ductwork in L shape sections may justify the increa ed ite as embly co ts
It is recommended that before a contract is finalised that consideration is given to the subject of site acces material handling and storage as tbcy havgt a strong influence on the cost efficiency of the overall activity of ductwOlk installation
B3 Handling To minilnise th risk of damage duct sections should be clearly identified and deliveries to site should be closely linked to the installation programme so as to avoid accumulation of
B1 Storage and Handling of Ra Material Material should be stored in suitably designed racking out of direct unJight Where possible the e racks should be metal to earth Edges of cut she t may be harp and protective gloves are advised Wearing teel toe-capped boots is recommended Most pIa tic sheet is manufactured with smootb mfaces andor is suppLied with protective coating Care must be taken to prevent accidental lippag of stacked materials Beiuoshy good electrical insulators the movement of stock unless earthed will allow the build up of stati All stock shapes are chemically stable at normal temperature Whil t some raw materials used in their manufacture may themselves pre ent a toxic hazard once incorporated into the lOck bape they no long r constitute such a hazard and no dermatitic bazard are known nor are any
unfiJied ductwork and minimise double handling It is important to recognise that ductwork panels joint and corners arc susceptible to damage and care must be taken wheu band ling such material through a site During handling individual item of duct work may be liable to light cross sectional deformation until thev become an integral pan of a completed ductwork system Whilst this may temporarily detract from its intended appearance thi deformation will not have any detrimental effect on the functionality of the finally a semblecl system Installation of duct work and asociated plant items ill illevitably involve manual handUng The responsibi Iiry of employers and employees to a ses the risk of personal injury during mallual handling operations is et out in the HS E publication L23 Guidance on Manual Handling Regulations 1992
environmental problems expected 84 Site storage
B2 fransport Large capacity vehicles with high-sided open or closed-top bodies are tlle mo t suitable for the transport of dllctwork Careful consideration should be given to the
Adequate floor space IDust be provided within tbe building for the site storage of ductvork Such storage shalt make due allowance for thc stOf(ne of ductwork in stacks such that access ~ egt
between them is of sufficient width to pennil the removal of item without interference to
unloading of transport on sit a not all siJes b n fit from the material handlino- and access facilities that exi [ in a manufacturing workshop such as crane- fork-lifts or loading bay Site handJiog facilities along with
adjoining sta ks Ductvork components should be positioned so a to avoid crushing Ductwork of small panel size may be stored horizontally however care should be exercised to ensure that tack sizes are limited 10 within
ehicular acce s restrictions may itilluence the type and ize of transport to be uWised
engtlls of ductwork should be positioned 0
the tmctural strength of the duct sections to prevent distortion of the lower sections within the stack
as to avoid crushing Lengths Witll projections such as branches and bends i1anges girths damper quadrauL should be loaded so as to
54
DW154 S1tciic(ltioll for Plastics Ductwork
85 Internal cleanliness of new ductwork The site storage of ductwork introduces the important cODsideration of maintaining the internal cleanliness of the ductwork R feren e should be made to HVCA documentshybull DWffM2 Guide to Good Practice - internal
Cleanliness of New Ductwork Installations If the above conditioDs can not be satisfied consideration should be given by tJle designer to amending the specification to include for Po t Installation Cleaning as covered by tJ1C HVCA documentshybull TRJ17 Guide to Good Practic - Cleanliness
of Ventilation Systems
APPE DIXC
Fi e Retardant inishes C1 Improvement in the fire retardancy of plastic
ducts can be achieved to varying degrees and is wholly dependent llPOll the surface coating laminating resin selected and construction specification adopted In some instances smoke emission is coILSidered equaUy with other speci fication requirernen ts of the materials resistance to ignition and bumjng It is therefore important for design rs to establ ish the clients and officers detailed requirements and not rely on a tbird party interpretation of fire resisting or fire retardant Where possible the specification should refer dir etly to compliance with a British or European Standard identifying the specific sections applicable There are various types of resin and mat rcLnforcements that can achieve a Class 1 surface spread of flame ratin o when tested according to BS476 Part 7 (1987) This test puts materials illto Class I - 4 in descending order of perfoDllance according to the rat and extent of flame spread over their surfac under standard beating conditions Materials should also be tested for flre propagarion to BS476 Part 6 (1989) Tbi tesr measures the amount and rate of heat evolved by the material when subjected to standard heating
conditions Test results are given as an index of Perfonnance (i) whicb is based on three sub indices (iJ (i1) (h) The higher the value of the Index of Performance (i) the greater is the material s contribution to fire growth The higher the value of the sub-index 0) rhe greater the ease of ignition aod flame spread The highest product performance classification as defined in Approved Document B of the Building Regulations is Class O This is acLlieved if a material surface of a composite ploduct i~ either a) composed throughout of materials of
limited combustibility or b) a Class I material which has a tlre
propagation index (i) of not more than 12 and sub-index (i l ) of nor more than 6
01 J Class 0 is not a cla$sif1cation identified in any British Standard test
There are resin system reported to be classified to Class O when tested to BS476 Pcl1S 6 and 7 however designers need to ensure that such sysrems can be applied to their proposed design In propriety resinmat system available the fabrication techniques and COITect application are critical to the integrity of the reinforcing and clas ificatiol1 For example in some systems the u e of a non-fire retardant gelcont on a fire retardant substrate would reduce the classification For further information see HVCA publication DW144 Appendix D
55
DW154 SplCijiClIliol1 for Plastics Ductwork
x Guidance otes For nspectmiddoton Servicing a d
Clean-ng Access Openings
D1 GE ERAL This appendix highlight in ummary fOI111
the acce considerations that hould be made by the design r iD terms of inspection servicing and cleaning Having considered the seop and the design of the dUCI work system relative to the guidelines outlined below the designer should clearly indicate which levels of acces should be incorporated into the manufacture of a new duct work system (See Table 14 and Note I b low it
D2 DESIGN CONSIDERATIONS
D21 In ptction and servicing requireshyments are set out in Section 15 of Lhis specification
D22 Cleaning requirements are set out in the HVCA pubUcation TRl7 Guide to Good Practice Clean Lines of Ventilation Systems and the guide tates The precise location ize and
type of access would be dependent on the type of ductwork cleaning inspection and te ting metbods to b adopted Care protection and standards of cleanliness prior LO cOlllmisionin o
are set out in th AV A publication DWITM2 Guide to Good Practice Internal Cleanliness of New Ductwork Installations and th guide state Wh re specific limits of cleanliness are required ductwork sball be cleaned after installation by a spcialist cleaning contractor It will b in the interests of tht desioner botb financially and practically to cunsider employing a specialist c1eauing contractor at tbe
outset of a contract to internally clean newly installed ductwork prior to bandover This approach would reali e the following benefit shyi) Tb actual numb r of cleaning
access panels could be detennined to suit the method of cleaning to be adopted (This may be 1 s than the maximum requiremen listed under Lev 13 of Table 14)
ii) Clear directions could b given to the ductwork contractor as to tJle size and location of cleaning access panels that are required to be fitted during the mauushyfaclunng pro s
iii) The specialist cleaning operation prior to commi ioning vould enable the cleaning contractor to verify the practical acee requirement for the future cleaning operation associated -vitb a regular maintenance programme
iv) A specialist cleaning operation prior to commissioning would allow the designer to omit from the speeilicatiolJ the DWrrM2 requirem nt for factory sealing protection wipe downs and capping-off
v) Specialist Ieall ill 0 to the measurable standard defin d in TR17 will allow an objective definition of cleanline to be achieved
Car ful consideration must be gIven by the designer to the practl aJ problems associated witb the manufacture and fitting of suitably si Led access panel on small cross section duct and on the circular faces of rouod and flat oval ducts in particular
D23 Special con ideration must be given by the de igner to the practical problems associated with gaining personnel access to heavily congested ceiling areas and multi-la red du twork systems This approach would avoid
56
DW154 Spfciication for Plastics Ductwork
the possibility of access panels being D3 ACCESS 0 IN-LINE EQUIPMENT incorporated into a ductwork system at the This appendix unly covers acc il1spection manufacturing stage that were later found in through the ductwork body adjacent to an item practice to be inaccessible for either ervicing of in-line equipment and not openings in the or cleaning activities equipment itself
able 14 Acce requirements for inspection servicing and cleaning
HVCA PUBLICATIO REFE NeE (uidtgt 10 Gund Prartict
Adjace t OW144 Cleanliness orVcnlillltio S~lcr~ fRjJ7
in-line LeyeJ 1 Level 2 Level 3 ite sequipment pcdionSen lcin~ Section d C1eaniJl( SUn(O)lnspc lion Palle ltk~m_n
2011 (minimum OiL Jubje-ct to duct ~zel (ft~ -Panels
Control Da pcrs One (inspection) 203 One 300 mm x 200 mm Both sid Fire Dampers One (sCTjdJl~) 20211 One 300 0101 x 200 mm One side HeatingCooling Coils One (inspedion) 20213 One 300 mm x 200 mm (lIpstream) Both sides Attenuators (rectangular) None required One 300 mm x 200 mm (downstream) Both sides Attenuators (circular) one retluired One 300 mm x 200 mm (downstream) One side Filter Sections One (inspection) 20212 one required Uoth sides Air Turn Vanes None requjred None required Both sides Changes of Direction None required one required One side In-Duct FansDevices One (inspection) 20213 None required Both sides l
1 In the absence of any indication by the designer only Level ) access will be jncorporated into a new ductwork system
2 Tbe panel izes associated with Lev lis I and 3 acee s ar e middottablished by reference to Section 20 of DW144 and Section 2 ofTRll7 respectively
57
DW154 Speclfifatio for Plastics Ductwork
pA XE
B-bliography Included in this Bibliography are technical pUblications which may be of interest (0 ductwork designers fabricators and erectors and to tho e in the heating ventilatlng air conditioning industries generally nquiric should be made of the relevant organisation at the address quoted Since its publication other addresse contained within 0V154 mav have changed and some pubJicalions may have been superseded
HEATING AND VENTILATING CONTRACTORS ASSOCIATION
4 Palace Court London W2 4JG Telephone 020-7229 2488 Fax 020-7727 9268
Orders fo FlY A Publications Old Matlsion House Eamont Bridge Penrith Cumbria CA 10 2BX (Telephone 01768 864771 Fax 01768 86718) Email hvcapoblicationshvwelfarecouk DWn 44 pe ilicatiun for sheet mctal duclwork (Iow- mediulllshy
and high-pressure) 1998) DWIl4 A practical guide to dUGI ork I akage te ting
(revised 2000) DWII54 Specification for plastic~ duct rk DW171 Guide to good Practice for kitchen venlibtion system DW191 Guide to good pracuce glass fibre ductwoJk DwrrMI Acceptance cheme for new products - Redangolar cro
joint classification Guide to good pra tice - Internal cleanliness of new ductwork installations Guide to good practice for the design for the Installation of lire and smoke uampers
J 1Other puhlications
HampV safely guide 5th edition JS2 Tool box talks JS5 Weldlng Safety booklet JSI9 afety facts bo klet Fact sheets 1-24 2nd edition JS2J COSHH manual volume 1 Advice on compliance with the
regulations 1521A CO I-rH manual volume 2 Asses mcnt h ets JS23 Ri k management manual TR3 BrazinltT and bronze welding of copper pipework cUld sheet
(I 976) TR5 Welding of carbon steel pipework (1980)
TR6 Guide to Good Practice for Site Pre sure Testing of Pipework (19 0) Guide to good practice cleanliness of ventilation Ylem
CHARTERED IN TITUTlO OF BUILDING SERVICES E G EERS Delta House 222 Balham High Road London SW12 9BS rTelephone 020-8675 5211 Fax 020-8675 5449) CIBSE Guide Volume A Design Data Volume B In tallatiol1 and quipment Data Volume C Reference Data
CommlssioniJIg Codes These Codes eover the preliminary checkS eUing to work and regulation of vanous catcgories 0 plan The Codes give a guide to design implications Series A Air Distnbution Systems Series B Boiler Plant
ri s C Automatic Conlrol ystems Cr1es R Refrigerating Sy terns
Sene iN Water Distribution Systems
Technkal Memonllda TM 4 Design Notes for the Middle East TM bull Design otes for Ductwork TM 13 Minimi iog lhc Risk of egiounaires Disease
Research Reports RROI95 Ventilation system hygiene - A review of published
infomlatioo on lhe occurrence and ffects of Olltamination Rl~02J95 Air-to-air heal rec v ry RR0395 rnfluen e of HV C on smoke detectors
ATlONAL ENI [ERING SPECIFICATION LfMITED Southgatc hamber 3739 Southgate Street Winchester S023 9EH (Telephone 01962 842058 Fax 01962 R(8982) BUfLDING S RVICES RESEARCH AND [ ORMATION ASSOCIATIO Old Bracknell Lane West Bracknell Berkshire RG 12 4AH (Telephone Brackl1eU (01344) 426511 Fax 01344 487 -7 )
Application Guides AGln4 De tglJing Vana~le Volume middotylans for KOOnl
iir Movement AG1I91 Commissioning of V Sylcms in Buildings 11 6194 Fire Dampers
B) 94 cntiJalion or KitcneTls
AG389 The Commls ionin of Air Systems In Buildmgs AH2192 Commissioning of Bern - A ~ode of Practice TN2417 I Fire Dampec il) Ventilating Ducl
BEATING VENTILATING A AIR CONDITION G MA UFACTURERS ASSOCIATIO (HEVAC) HEVAC Henley Road Medmenham Marlow Buck SU 2ER (Telephone 01491 578674 ox 01491 575024 Emoimiddot infofetacouk)
Publicatjons Air Diffusion Guide Guide to Air Handling Unit Leakage Testing Guide to Good Practice Air Handling Unit Real Room Acoustic ~ st Procedure Specification for the ertiiicatioll ofAir Filters Method of Test for Water Rejection PerfOnTlatce of Louvrcs Subjected 1(1
Simulated Rainfall Test Procedure for Acoustic Loo cs Specification 10 Floor GrilJes - Types Performan e and Method ofTest Specification for the Determination of the Collection Efficiency of SilJ1d
Trap Louvre Domestic Mechwlical Vclltllalion Systems with Heal Recovery Fan Application Guid
~an and Ouctwork Installation Guide Guide to Fan Noise and Vibration
pecification of Requirements for JallJral Smoke and Heal Exhausl Ventilators
pecification for Powered Smoke and Heat Exhaust Ventilators
Specification of Requirements for Smoke Curtains Design Gujue of Smoke Ventilation for Single Storey Lodustrilll Building~
Including those with Mezzanine Floor and IIi Racked Storage Warehou es - Issue 3
Guidance for the Design of Smoke entilation YSlem for Covered and Undergrollnd Car Parks - lssue 1
Application of SOloke Control Equipment and Syst m Guid to Good Practice - Isue J
58
DW154 Sp(C~tiifitiol for Plastics Ductwork
BRITISH STANDARDS INSTIT TION Sales Department 101 P ntooviLle Road London NI 9ND (felephone 020-78 1 78801)
CP 413 1973 Ducts for building ervices
SS 476 Fire tes on building matenals and lruc(ure
Part 4 19 4 Non-combustibility lest or materials
Part 6 I Fire propagation lest for materials
Part 7 1993 Surface spread of tlarnJ tesls for materia
Part 20 1987 Fir resistance of elements of construction
Part 21 1987 Fire r sistlUlce of loadbeanng elements of construction
Part 22 1987 Fhe istallceofllon-loadbearing elemcllts ofconsttuclion Part 23 1987 Contribution of componcnts to the fire resistance 0 a
structure
Part 24t987 Fire resi lance of wl1lilation ductl
SS 5588 nan 919 0 Fire Precautions III thc desIgn and OOSlnJ lion of buildings
S 729 1971 Hot dip galvanized oatiugs (or irOIl aod stcel articles
BS 1449 Steel plate sheet and Irip
Pan 11991 Carbon steel plate heel and strip Part 2 1983 Stainless steel plate sheer and strip
and
B middotENJOI49-2 996 BSEN 10149- 1991)
BSEN 10131 1992
BSEN22063 Sprayed metal coarings 1994 Protection of iron and steel by aluminium and zinc against
atmospheric cOlosion Irotectiotl of iron and ste I against corro ion and oxishydation at elevared temperatures
BS 353 1981 Glossary of lerms relnting to thermal insulation
BS ISO 1479 Self-tapplngscrewsandmetallicdri c crew
B -lSO 7049
1994
B 4800 1989 Painl colour for building purposes B 4848 l0 rolled structural steel sections
Part4 1972 Equal and unequal angles BS 5422 1990 Specification for the use of therm illuating matcriulS
SS 5720 1979 ode of practice for mechanical veutilating and air C 11shy
dirionin bull in building
l3S PR 12814-1 Bend resting for plasric welds
SS PR 12814-2 Tensile testing for plastic welds
SS PR 13067 Appro altesting for plastic welds
BS PR EN I 100-] Vi ual in pection ofplaslic welds
SHEET METAL AND AIR CONDITIONING CONTR-CTORS NATIONAL ASSOCIATION INC (SMACNA) Headquarters 420 I Lafayeue Center Drive Chanlilly Virginia 2051-1209
Mailing Address pa Box 221230 Cbantilly Virginilt120 153-1230
Telephone (703) 803-2980 Fax (703) 803-3732
Accepted IJJdustry Pl3Gtice for Industrial Duct Constnlelion 197 ) i-rchitecmral Sheet kwl Manual ([993)
Comractors Guide lor Modification 10 ooslruerion Colllraets 1993 Ducted Eleclric Heat Guide for ir Handling Ssrerns (1994)
En~rgy ollservatioD Guidelines (1984) Energy Recovery Equipment yslClllS (199l
Fibrou GIns Duct onS1ntClion Standards (1992)
Fire Smoke amp Radiation Damper In tall Guide for HVA Syst ms (1992) Guide t leel Stack 1(95)
HVA Air Duct Leakage Test Manual (19 ) HVA COlllmissioning lvlanual (1994)
H A Duct Construction Standards-Metal amp Flexible (1995) Addendum 01 (Nov 1997)
HVA Duct Systems Inspection Guide (1989)
HVA ySlems-Application (1986) nVAC ByternS-DLlct D ign (1990)
HVi Systems-Testing Adjusting amp Balancing (1993)
indoor Air Quality Manual (1993) tcheu quipment Fabrication Guidelmes (1990)
Managers Guide for elding (1993)
Rectangular Industrial Duct Cons1TUction Standards (19 0) Round Industrial Duct oustmction Standards (1977)
Sei mic Restraint Manual (1991) (wl Appendix E 1993) SMACNA Ma le Index ()fTechnical Publications (1995) Tbennoplnstic Duct CPY ) Construction Manual 1994)
DEPARTME OF THE ENVIRO MENT (Publications Centre) H Stationery Oflice 5 Nine Elms Lane London SWS 5DR
MampEJ 011972 Electrical in tallat1011 in buildings ( ew Editiou)
IampE 0319 Healing hot and cold wat r steam and gas losla1lations for buildings
M amp - No4 1970 Central heating and hot and cold ~ ateT in tallations for
dwelling
M amp ENo100 1971 Mechanical ventilation for building~
ASSOCIATION FOR SPECIALIST FIRE PROTECTlO As ociation House 235 Ash Road AJdershot Hampshire GUl2 4DD
Telephone OJ25221322 Fax 0 J252 333901
lublicalioos Fire Ratcd and moke Outlet Ducrwork An Industry Guide t Design and InSlalla lioll
HEALTH AND SAFETY EXEC TIVE Rose Court 2 Southwark Bridge London SEl 9HS Telephone 020-7717 6000
TWJ THE WELD G TlTUTE Abington Hall Abington Cambridge CB16AL Telepbone 0 J223 89162
Publication DatJ Oil w~ldll1g of lhermopla lics
59
DW154 wciiwlioll for Plastics Ductwork
A -=--DIX
Factors
Specific gravity shy pp = 091 approx UPVC = 14 approx
Some miscellaneous conversion factors
To convert
Length Inches to millimetres Feet to metres
Multiply by
2540 03048
To convert
Millimetres to inches Metres to feet
vIultiply by
003937 3281
Area Square inches to square millimetres 6452 Square millimetres to square inches 000155 Square feet to square metres 00929 Square metres to square feet 10764
Volume Cubic feet to cubic metres Cubic feet to litres Gallons (UK) to litres
002832 2831 4546
Cubic metres to cubic feet Litres to cubic feet Litres to gallons (UK)
35315 00353
022
Mass Ounces to grams Pounds to kiJograms Tons to tonnes
2835 04536
1016
Grams to ounces Kilograms to pounds Tonnes to tons
003527 2205
09842
Volume flow Cubic feet per minute to cubic Cubic metres per second to cubic
metres per second 0000472 feet per minute 2119 Cubic feet per mIDute to litres Litres per second to cubic feet
per second 04719 per minute 2119
Motion Feet per minute to metres per second 000508 Metres per second to feet per minute 197
Pressure Inches water gauge to millibars 2491 Inches wateJ- gauge to pascals (Pa) 2491 I Pa = I ewton per square metre = 10-2 millibars
60
Heating and Ventilating Contractors Association Esca House 34 Palace Court London W2 4JG
Tel 020 7313 4900
e-mail contact Itvcaorguk web site wwwhvcaorguk
Fax 020 7727 9268
DW154 Sp(Cii(ltJll for Plastics Ductwork
STANDARD COMPONENT DRAWINGS - CIRCULAR
DRAWINGltIC DETAns
-
I
I
~
I I I High Velocity Discharge Terminal 103 I
I
I I
J I I 1 ~--
Offset Stack Discbarge Terminal 104 1
~ I e --(-
I
N
I
I
I~
I I Vertical Oischarge with Weather Cowl 105 I
--1--1 I
I
GAPI I
RTl AL DISC) lARGE WITH W ATIIER COWL
45
DW154 SpecUicatoll for Plastics Ductwork
STANDARD COMPONE T DRAWINGS - PLA TEQUIPMENTIMISCELLANEOU
FIG DRAWING DETAILS
106 ~~~ Rectangular Attenuator
107 ~- Circular Attenuator
108
~ Beod Attenuator
109 J ~(f) Heating Coil
110 J ftte Cooling Coil
III Jc[ Electric Heating Coil
112 X F
Humidifier
113 [H XX Axial Fan
114 ~fB1famp Noo-standard Ductwork Cross hntchillg (of any separate type) indicates by reference to a key any non DVil54 ductwork system
115 2llIIIIJIIIIIll Flexible Ductwork
46
DW154 SJeCUicll(iol1 for Plastics Ductwork
TABLE 12 - STANDARD ABBREVIAT ONS
ABBREVIATION FLL
AD Acces Door
AFF Axial Flow Fan
AHU Air Handling nit
All Aluminium
AP Acess Panel
AT Attenuator
AV Air enninal Unit
BE 81ank nd
BQ Blast ate Damper
CC Cooling Coil
CF Centrifugal Fan
CTA Cross alk Attenuator
CVU Constant Volume Unit
DP Drain Point
EEC Electric Heating Coil
El Expansion Joint
FAl Fresh Air Inlet
FA From Above
FB From Belo
fBPP Fabric Backed Polypropyl-ne Sheet
Flexle Flexible Connection
lexfD Flexible Du t
C False Ceiling CO an oil Unit
fD Fire Damper
FFL Finished Floor Level
FJ Flanged Joint
FOAM Rigid Polyurethane Self xtinguishing Foam
FOB Flat on Bottom
FOT Flat on Top
GAM Galvanised after ManufacttrJc
GRP Glass Reinforced Plastic
GSS Galvanised Sheet Steel
HC Heating oil
HD and controlled Damper
HH Hand Hole
HL High Level
HVD High Velocity Discharge
IC Inspection Cover
ID lri Damper
IFS Intumescent Fircleevc
47
DW154 Specification for Plastics Ductwork
TABLE 12 - STANDAR ABBREVIATION CONTINUED
ABBREVIATION
IU
L
tv1D
MS
NRD NTS
OBO
OE
PHD
PD
PP
PP
PRD
PVC
RFC
RSC
R
SBO
SO
S1 TST
SSL
TA
TB
TO TJ
TP
TV
TV
OS
UPVC
S
V
VAV
50 RSA
FULL
Induction Unit
Low Level
Motor controlled Damper
Mjld Steel
on Return Damper
at to cale
Opposed Blade Damper
Open End
Parallel Blade Damper
Pneumatic controlled Damper
Polypropylene
Self xtinguishing Polypropylene
Pressure Relief Damper
Polyvinyl Chloride
Rolled Form Chamlel
Rolled Steel Channel
R fUnit
Singl Blade Damper
Smoke Damper
Slip Joint
Stainl t el
tructural Slab Level
To Ab vc
To Blow
Top Down (In Direction of Flow)
Telescopic Joint
Test Point
TU111iog Vane
Top Up (In Direction of Flo )
Voles Otherwise Stated
Unpl3sticisecl Polyvinyl Chloride
Underside
Ultra Violet Light
Variable Air Volume
Rolled Steel Angle (Vith Size)
48
DW154 SJeriiflllioll for Plastics Ductwork
A2 DUCT PRESSUREAPPE DXA Ductwork con truct d to DWIl54 will bebullbullbullbullbullbullbullbullbullbullbullbullbullbull
Air Leakage From Ductwork To be read in conjunction with DW143 A practical guide to Ductwork Leakage Testing
CAUTION As highlighted ill both this docul1lenr and DW14 I lot ellough emphasis can be placed 01 the fact that except for high pressure class C the much more stringent ductwork constructional standard brolght about b the general acceptance of DW154 have irtlally negated the requirement for leakage-testing It is essential lO realise lhat except where it is mandatory this doclllllelll is nOl an endors ~lIlent of the rourine testing of ducts bllt purely a guide to outline the procedures for cononnity with the air leakage limits ill Table l Where the specified methods of assembly and
A3sealing of dlcls are u ed a vi ual inspection wil ordinarily sl~fll e for ver(iatioll of a well engineered and a ceptahfy airtight COl1strucrioll WHERE NOT MANDATORY DUCT LEAKAGE TESTING IS GENERALLY AN UNJUSTIFIED AND SUBSTANTIAL EXPENSE
A1 INTRODUCTION L akage from ducted air distribution systems is an Lmportant consideration in the design and operation of ventilatjon and air conditioning middotystems A ductviork t)ystem tbat ba limited air leakag within defiucd limits wiH cnsUft
that tile design characteristics of the sytem can be maintained It wilJ also ensure that energy and operatLonal cosb are maintained at optimum levels DucLwork constlucted and Ulstalled in accordance with DW154 should minimise a level of air leakage that it) appropriate to tll operating static air pre sur in tile system
A4However it is recouuised that tbe environment in wtJich middotystems are installed is not always conducive to achieving a predictable level of quality in term of system ajr leakage and it is therefore accepted that designer may sometimes require tlle ystem to be tested in part or in total It should be ecogni ed that the testing of duct systems add a ignificant cost to the installation and incur some extra tjm within the programme (Se 47 and 64 re mandatory te-sting)
manufactured to a structural standard that is compatible with the system operating pressure There are three classes of duct con truction to eorre pond with the three pre ure clas meations Class A Lo pressure ducts suita le for a maximum positive operating pressure of 500 Pascal and a maximum negative pressure of -500 Pascals Class B IVledium pressure ductmiddot suitable for a rnaxilnuJJl positive operafjn o pressure of 1000 Pascals and a maxllnum negative pre sure of -750 Pa cal Class C High pre sure ducts suitable for a maximum po ilive operating pressur of 2000 Pa cals and a maximum negativ pres ur of -750 Paltcals
LEAKAGE FROM DUCTWORK Leakao-e front pia tic air ducts occur at the joint~ and is therefore proportional to the total surface area orthe du twork in th system Tb level of leakage i imilarly related to tIle air pres ure in th du t system and whilst there LS n precis formula for calculating the level of air los it i generally accepted that leakage will increase in proportjon to pressure to rbe pOvver of 065 The effect of air leakage from high pressure velocit ductwork is critical tn terms of system perfomlan dege energy consumption and the risk of high frequency noise as ociated with leakage These problems are le critical with medium pressure 10 ity systems but should be con idered Low pres mevelocity ducts present the lowe~t
ri k in tenn of tbe effect of leakage on the operation of the s stern
SYSTEM LEAKAGE LOSS As there i no di ct relatLonship between th volume of air conv yed and the surface area f the ductwork sy tern required to match the building configuratmn it is difficult to express air leakage a a percentage of total air volume Similarly the operating pressure will vary throughollt lh 3 system and a leakage is related to pre me the calculations ar comple However it is generally ac epted tbat in typical good quaJjty systems the leakage from
49
DW154 Specificatioll for Plastics Ductwork
each class of duct llnd r operating condition will be io the region of CIa S A low pressure 6 Clas B medium pres un 3 Clas C high pressure 2
A5 SPECIFYING AIR LEAKAGE TESTING Re peeting both the co -t and programme implications a sociated with te ling du 1 for leakage the designer may for example indicate that a particular system is te ted as follow
a) High pressure ducts - all tested b) Medium pr ssure duets - 10 of the
ductwork shall be s eet d at random and tested
c) Low pre sure - unte ed In any case where a random te t i elected for medium pre sure ductmiddot the followin c1au~e is suggested for inclusion by the de ign r
The designer hall elect at random a maxirnwlI of 10 of the dUCl system to bt tested for air leakage The duct hall be tested af the pressure recommended in Table J3 for the assifi atiol for the ectiol1 of the ductwork that is to be tested The tests shall be carried Ollt as the work proceeds and prior to the application of thermal insulation In the event of test failure of the randomlY selected section the designer shall have The right to select two La1her e tiolls at random for resting Where succes ive failures are identified there shall be a Tight to require rhl COl11raCWr 10 apply remedial attention to the complete ductwork system Th contractor shall provide documented eviden e of the calculalions used to arrive (1
the allowable 10 I for the section to be tested and the client or his agent shall willess and sign the results of the test
able 13 Air leakage rates
Maximum leakage of duct work Static
prcssUft Low-pressure edium-prc-sure I Iigh-prebull me diJfercntial Class A Class B Class C
1 2 J 4 Pa Litres per second per quare metre of surface area 100 054 018 ZOO 084 028 300 110 037 400 132 044 500 153 051 600 058 019 700 064 021 800 069 023 900 075 025
1000 080 027 1100 1200 1300 1400 1500
029 030 032 033 035
1600 1700 1800 1900 2000
036 038 039 040 042
Note Recommend d mean test presures are highlighted iD bold type with the actual selection being left to tll test operator
50
DW154 Sfeeiieaioll for Plastics Ductwork
A9
A10
and air leakage classification for the y em under test
DESIGNERS CALCULATIONS The designer can middotaJculate with reasonable accuracy the predicted total loss from a ystem by
a) Calculating the operatin presure in each ection of the sy tern
b) Calculating the surface area of the ductwork in each correspondin pre lire s ction
c) Calulating the allowabl~ los at the operating pressure for each ection of the system (see table 13 for allowable leakage figures)
VARIABLE PRESSUR S IN SYSTEMS De igner can achieve significant co t saving by matchina operating pressures throughout the system to constmctional standard and appropriate air leakage testing eO the practice of specifying construction tandards for whole duct sy tems based on fan discharge pre sure may incur unnece sary costs on a project For example ome large sy terns ould well be classiC ed for I akage limits as follows
Plant room risers CJas C Main floor distriblltJou CIa B Low pre sure outlets Cla A
A6 SPECIAL CASES There may be ~itLlations on a project where circumstance dictate thal pecial consideration be given to containing air loss s eg a long mn of duclwork may incur a di -proportjonate level of air 10 s In ca es such as thi example the designer can specify an improved tandard of airtighmess ie 80 of alJo~able 10 s for la B Ju ts The designer sbould not specif a CIa C t sI at CIa s C pressure for a CIa s B ducl
A7 SUGG S ED RANGE OF TES ING
A8 TESTING OF PLANT ITEMS Items of inline pJant (eg Fig 106 to 115) will not normaUy be included in an air I akage test The dllctwork contractor may indud such itelllS in tbe te t jf rh quipm ot has a certificate of COnfOlnlity for Ihe pres ure clas
bull High pressure duct bull Medium pre sure ducts bull Low pre sur ducts bull Exposed extract syst ID bull Ceiling void extract
systems bull Secondary ducts from
VAV or fan coil units bull Flexjble duct bull Final connections and
branches to grille and diffusers
100 test See A5 Untested UDt sted
Untested
Untested Untested
Untested
SI
i
DW154 SJecijicafion for Plastics Ductwork
ig 116 Permitted leakage at various pressures
Leakage in litres per second per square metre duct surface area
Vgt
o ltgt 0 ltgt N
ltgt Cgt
0 0 cc
0 0
~
g =
g ~
c 0
J
ltgt 0 I
~ ] tn
ltgt ltgt
In ol
~ 0 ~ 8 ~
~
c ltgt ltgt
~ CJ
~ ~ ~ ~ 8
0shyij
~ ~ ~ t
ltgt ltgt 00
l
~
~ Q
c C
~ rshy
e ltgt
I 1
I Cgt ltgtv
c Co ~
~~ ~ 10
I
0 Cgt
fJshyq 410 ) 1 ltgt
ltgt N
~ shy ltgt ltgt
~ I 1
c
52
DW154 Specificatio for Plastics Ductwork
Example of a completed test sheet Test No
General
Name of job N~ jC43Pt(r2lef Building Repound ~(~~0
Part 1 - Physical details
a Section of duct work to be tested ~(diffPIfff~el1f3rd Floor
b Drawing Number g91~~ c ssure aSSJ L atlOn V~Jl~IRfYgtg~~lPre Cl T Class C
d Test static pressure -(9 raErq~ ~~~~-~~J~~~ ~~ ~~~~ll
Leakaoe factor 9~-tre3$ecMz I OM REFTOTABLE 13)e b bullbullbullbullbullbullbull
f Surface area of duct under test Q~tJJItetre$ CPROMCALCU TIO BELOW)bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull ampampamp bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull
g ]Vlaxi mum permitted leakage -~ (~i~~0 ~~r~~ ~~~l-~-11~ ~~~Q
Part 2 - Test particulars
a Duct static pressure reading 9QFt~q~ ~ middot~~~1 ~~
b Manufacturer and type of liow measuring d vice (-~~~cJ~Y-9Q7EYg c Range of measurement of now measuring device QtP)OQ~(e~~~0I~~~~1~I~ ~~~~~~W~
d Reading of flm measurin o device pmiddot IFROM RIO)ftscag ~
I (DERlVED [ROM CHART SUPPUED WITH RIG US 0 ud)1e Interpreted air flow leakage rate ~(~~~f~~~ (~l~~~~~~~~~~~~~~~~~I
f Duration ~~~~~norn~allY l~ lnil1Ut~~d~~~ it1~ W~ Date of test ~(lITled ut by Wltll s ed by ~ ~
(~lJ MIJLrr) (Si~rrfltJUYJ
Printed Name 1~g0f~ Printed Name ~~Y~9~ and Company 7jl~~~~~( UJd CompanY AB COII$Itallt8
Width and depth or diameter
Periphery ength Area
millimetreS millimetres metre qL1are metre
800 x 750 3100 1755 5440
600 x 650 2500 557 1193
300 x 300 1200 120 144
305 din 958 700 670
250 dia 785 450 353
TOTAL 8000
53
DW154 Specijilarion for Plastics Ductwork
pA XB
Guida ce No es For he ransport Handling and
Storage of uctwork
avoid damage to adjacent duct panels In somc ca es particularly on con acts calling f r repetitive sizes the use of timber jigs and spacers may be justified Where reduced bulk and greater protection are major factor such as consignments for export transporting ductwork in L shape sections may justify the increa ed ite as embly co ts
It is recommended that before a contract is finalised that consideration is given to the subject of site acces material handling and storage as tbcy havgt a strong influence on the cost efficiency of the overall activity of ductwOlk installation
B3 Handling To minilnise th risk of damage duct sections should be clearly identified and deliveries to site should be closely linked to the installation programme so as to avoid accumulation of
B1 Storage and Handling of Ra Material Material should be stored in suitably designed racking out of direct unJight Where possible the e racks should be metal to earth Edges of cut she t may be harp and protective gloves are advised Wearing teel toe-capped boots is recommended Most pIa tic sheet is manufactured with smootb mfaces andor is suppLied with protective coating Care must be taken to prevent accidental lippag of stacked materials Beiuoshy good electrical insulators the movement of stock unless earthed will allow the build up of stati All stock shapes are chemically stable at normal temperature Whil t some raw materials used in their manufacture may themselves pre ent a toxic hazard once incorporated into the lOck bape they no long r constitute such a hazard and no dermatitic bazard are known nor are any
unfiJied ductwork and minimise double handling It is important to recognise that ductwork panels joint and corners arc susceptible to damage and care must be taken wheu band ling such material through a site During handling individual item of duct work may be liable to light cross sectional deformation until thev become an integral pan of a completed ductwork system Whilst this may temporarily detract from its intended appearance thi deformation will not have any detrimental effect on the functionality of the finally a semblecl system Installation of duct work and asociated plant items ill illevitably involve manual handUng The responsibi Iiry of employers and employees to a ses the risk of personal injury during mallual handling operations is et out in the HS E publication L23 Guidance on Manual Handling Regulations 1992
environmental problems expected 84 Site storage
B2 fransport Large capacity vehicles with high-sided open or closed-top bodies are tlle mo t suitable for the transport of dllctwork Careful consideration should be given to the
Adequate floor space IDust be provided within tbe building for the site storage of ductvork Such storage shalt make due allowance for thc stOf(ne of ductwork in stacks such that access ~ egt
between them is of sufficient width to pennil the removal of item without interference to
unloading of transport on sit a not all siJes b n fit from the material handlino- and access facilities that exi [ in a manufacturing workshop such as crane- fork-lifts or loading bay Site handJiog facilities along with
adjoining sta ks Ductvork components should be positioned so a to avoid crushing Ductwork of small panel size may be stored horizontally however care should be exercised to ensure that tack sizes are limited 10 within
ehicular acce s restrictions may itilluence the type and ize of transport to be uWised
engtlls of ductwork should be positioned 0
the tmctural strength of the duct sections to prevent distortion of the lower sections within the stack
as to avoid crushing Lengths Witll projections such as branches and bends i1anges girths damper quadrauL should be loaded so as to
54
DW154 S1tciic(ltioll for Plastics Ductwork
85 Internal cleanliness of new ductwork The site storage of ductwork introduces the important cODsideration of maintaining the internal cleanliness of the ductwork R feren e should be made to HVCA documentshybull DWffM2 Guide to Good Practice - internal
Cleanliness of New Ductwork Installations If the above conditioDs can not be satisfied consideration should be given by tJle designer to amending the specification to include for Po t Installation Cleaning as covered by tJ1C HVCA documentshybull TRJ17 Guide to Good Practic - Cleanliness
of Ventilation Systems
APPE DIXC
Fi e Retardant inishes C1 Improvement in the fire retardancy of plastic
ducts can be achieved to varying degrees and is wholly dependent llPOll the surface coating laminating resin selected and construction specification adopted In some instances smoke emission is coILSidered equaUy with other speci fication requirernen ts of the materials resistance to ignition and bumjng It is therefore important for design rs to establ ish the clients and officers detailed requirements and not rely on a tbird party interpretation of fire resisting or fire retardant Where possible the specification should refer dir etly to compliance with a British or European Standard identifying the specific sections applicable There are various types of resin and mat rcLnforcements that can achieve a Class 1 surface spread of flame ratin o when tested according to BS476 Part 7 (1987) This test puts materials illto Class I - 4 in descending order of perfoDllance according to the rat and extent of flame spread over their surfac under standard beating conditions Materials should also be tested for flre propagarion to BS476 Part 6 (1989) Tbi tesr measures the amount and rate of heat evolved by the material when subjected to standard heating
conditions Test results are given as an index of Perfonnance (i) whicb is based on three sub indices (iJ (i1) (h) The higher the value of the Index of Performance (i) the greater is the material s contribution to fire growth The higher the value of the sub-index 0) rhe greater the ease of ignition aod flame spread The highest product performance classification as defined in Approved Document B of the Building Regulations is Class O This is acLlieved if a material surface of a composite ploduct i~ either a) composed throughout of materials of
limited combustibility or b) a Class I material which has a tlre
propagation index (i) of not more than 12 and sub-index (i l ) of nor more than 6
01 J Class 0 is not a cla$sif1cation identified in any British Standard test
There are resin system reported to be classified to Class O when tested to BS476 Pcl1S 6 and 7 however designers need to ensure that such sysrems can be applied to their proposed design In propriety resinmat system available the fabrication techniques and COITect application are critical to the integrity of the reinforcing and clas ificatiol1 For example in some systems the u e of a non-fire retardant gelcont on a fire retardant substrate would reduce the classification For further information see HVCA publication DW144 Appendix D
55
DW154 SplCijiClIliol1 for Plastics Ductwork
x Guidance otes For nspectmiddoton Servicing a d
Clean-ng Access Openings
D1 GE ERAL This appendix highlight in ummary fOI111
the acce considerations that hould be made by the design r iD terms of inspection servicing and cleaning Having considered the seop and the design of the dUCI work system relative to the guidelines outlined below the designer should clearly indicate which levels of acces should be incorporated into the manufacture of a new duct work system (See Table 14 and Note I b low it
D2 DESIGN CONSIDERATIONS
D21 In ptction and servicing requireshyments are set out in Section 15 of Lhis specification
D22 Cleaning requirements are set out in the HVCA pubUcation TRl7 Guide to Good Practice Clean Lines of Ventilation Systems and the guide tates The precise location ize and
type of access would be dependent on the type of ductwork cleaning inspection and te ting metbods to b adopted Care protection and standards of cleanliness prior LO cOlllmisionin o
are set out in th AV A publication DWITM2 Guide to Good Practice Internal Cleanliness of New Ductwork Installations and th guide state Wh re specific limits of cleanliness are required ductwork sball be cleaned after installation by a spcialist cleaning contractor It will b in the interests of tht desioner botb financially and practically to cunsider employing a specialist c1eauing contractor at tbe
outset of a contract to internally clean newly installed ductwork prior to bandover This approach would reali e the following benefit shyi) Tb actual numb r of cleaning
access panels could be detennined to suit the method of cleaning to be adopted (This may be 1 s than the maximum requiremen listed under Lev 13 of Table 14)
ii) Clear directions could b given to the ductwork contractor as to tJle size and location of cleaning access panels that are required to be fitted during the mauushyfaclunng pro s
iii) The specialist cleaning operation prior to commi ioning vould enable the cleaning contractor to verify the practical acee requirement for the future cleaning operation associated -vitb a regular maintenance programme
iv) A specialist cleaning operation prior to commissioning would allow the designer to omit from the speeilicatiolJ the DWrrM2 requirem nt for factory sealing protection wipe downs and capping-off
v) Specialist Ieall ill 0 to the measurable standard defin d in TR17 will allow an objective definition of cleanline to be achieved
Car ful consideration must be gIven by the designer to the practl aJ problems associated witb the manufacture and fitting of suitably si Led access panel on small cross section duct and on the circular faces of rouod and flat oval ducts in particular
D23 Special con ideration must be given by the de igner to the practical problems associated with gaining personnel access to heavily congested ceiling areas and multi-la red du twork systems This approach would avoid
56
DW154 Spfciication for Plastics Ductwork
the possibility of access panels being D3 ACCESS 0 IN-LINE EQUIPMENT incorporated into a ductwork system at the This appendix unly covers acc il1spection manufacturing stage that were later found in through the ductwork body adjacent to an item practice to be inaccessible for either ervicing of in-line equipment and not openings in the or cleaning activities equipment itself
able 14 Acce requirements for inspection servicing and cleaning
HVCA PUBLICATIO REFE NeE (uidtgt 10 Gund Prartict
Adjace t OW144 Cleanliness orVcnlillltio S~lcr~ fRjJ7
in-line LeyeJ 1 Level 2 Level 3 ite sequipment pcdionSen lcin~ Section d C1eaniJl( SUn(O)lnspc lion Palle ltk~m_n
2011 (minimum OiL Jubje-ct to duct ~zel (ft~ -Panels
Control Da pcrs One (inspection) 203 One 300 mm x 200 mm Both sid Fire Dampers One (sCTjdJl~) 20211 One 300 0101 x 200 mm One side HeatingCooling Coils One (inspedion) 20213 One 300 mm x 200 mm (lIpstream) Both sides Attenuators (rectangular) None required One 300 mm x 200 mm (downstream) Both sides Attenuators (circular) one retluired One 300 mm x 200 mm (downstream) One side Filter Sections One (inspection) 20212 one required Uoth sides Air Turn Vanes None requjred None required Both sides Changes of Direction None required one required One side In-Duct FansDevices One (inspection) 20213 None required Both sides l
1 In the absence of any indication by the designer only Level ) access will be jncorporated into a new ductwork system
2 Tbe panel izes associated with Lev lis I and 3 acee s ar e middottablished by reference to Section 20 of DW144 and Section 2 ofTRll7 respectively
57
DW154 Speclfifatio for Plastics Ductwork
pA XE
B-bliography Included in this Bibliography are technical pUblications which may be of interest (0 ductwork designers fabricators and erectors and to tho e in the heating ventilatlng air conditioning industries generally nquiric should be made of the relevant organisation at the address quoted Since its publication other addresse contained within 0V154 mav have changed and some pubJicalions may have been superseded
HEATING AND VENTILATING CONTRACTORS ASSOCIATION
4 Palace Court London W2 4JG Telephone 020-7229 2488 Fax 020-7727 9268
Orders fo FlY A Publications Old Matlsion House Eamont Bridge Penrith Cumbria CA 10 2BX (Telephone 01768 864771 Fax 01768 86718) Email hvcapoblicationshvwelfarecouk DWn 44 pe ilicatiun for sheet mctal duclwork (Iow- mediulllshy
and high-pressure) 1998) DWIl4 A practical guide to dUGI ork I akage te ting
(revised 2000) DWII54 Specification for plastic~ duct rk DW171 Guide to good Practice for kitchen venlibtion system DW191 Guide to good pracuce glass fibre ductwoJk DwrrMI Acceptance cheme for new products - Redangolar cro
joint classification Guide to good pra tice - Internal cleanliness of new ductwork installations Guide to good practice for the design for the Installation of lire and smoke uampers
J 1Other puhlications
HampV safely guide 5th edition JS2 Tool box talks JS5 Weldlng Safety booklet JSI9 afety facts bo klet Fact sheets 1-24 2nd edition JS2J COSHH manual volume 1 Advice on compliance with the
regulations 1521A CO I-rH manual volume 2 Asses mcnt h ets JS23 Ri k management manual TR3 BrazinltT and bronze welding of copper pipework cUld sheet
(I 976) TR5 Welding of carbon steel pipework (1980)
TR6 Guide to Good Practice for Site Pre sure Testing of Pipework (19 0) Guide to good practice cleanliness of ventilation Ylem
CHARTERED IN TITUTlO OF BUILDING SERVICES E G EERS Delta House 222 Balham High Road London SW12 9BS rTelephone 020-8675 5211 Fax 020-8675 5449) CIBSE Guide Volume A Design Data Volume B In tallatiol1 and quipment Data Volume C Reference Data
CommlssioniJIg Codes These Codes eover the preliminary checkS eUing to work and regulation of vanous catcgories 0 plan The Codes give a guide to design implications Series A Air Distnbution Systems Series B Boiler Plant
ri s C Automatic Conlrol ystems Cr1es R Refrigerating Sy terns
Sene iN Water Distribution Systems
Technkal Memonllda TM 4 Design Notes for the Middle East TM bull Design otes for Ductwork TM 13 Minimi iog lhc Risk of egiounaires Disease
Research Reports RROI95 Ventilation system hygiene - A review of published
infomlatioo on lhe occurrence and ffects of Olltamination Rl~02J95 Air-to-air heal rec v ry RR0395 rnfluen e of HV C on smoke detectors
ATlONAL ENI [ERING SPECIFICATION LfMITED Southgatc hamber 3739 Southgate Street Winchester S023 9EH (Telephone 01962 842058 Fax 01962 R(8982) BUfLDING S RVICES RESEARCH AND [ ORMATION ASSOCIATIO Old Bracknell Lane West Bracknell Berkshire RG 12 4AH (Telephone Brackl1eU (01344) 426511 Fax 01344 487 -7 )
Application Guides AGln4 De tglJing Vana~le Volume middotylans for KOOnl
iir Movement AG1I91 Commissioning of V Sylcms in Buildings 11 6194 Fire Dampers
B) 94 cntiJalion or KitcneTls
AG389 The Commls ionin of Air Systems In Buildmgs AH2192 Commissioning of Bern - A ~ode of Practice TN2417 I Fire Dampec il) Ventilating Ducl
BEATING VENTILATING A AIR CONDITION G MA UFACTURERS ASSOCIATIO (HEVAC) HEVAC Henley Road Medmenham Marlow Buck SU 2ER (Telephone 01491 578674 ox 01491 575024 Emoimiddot infofetacouk)
Publicatjons Air Diffusion Guide Guide to Air Handling Unit Leakage Testing Guide to Good Practice Air Handling Unit Real Room Acoustic ~ st Procedure Specification for the ertiiicatioll ofAir Filters Method of Test for Water Rejection PerfOnTlatce of Louvrcs Subjected 1(1
Simulated Rainfall Test Procedure for Acoustic Loo cs Specification 10 Floor GrilJes - Types Performan e and Method ofTest Specification for the Determination of the Collection Efficiency of SilJ1d
Trap Louvre Domestic Mechwlical Vclltllalion Systems with Heal Recovery Fan Application Guid
~an and Ouctwork Installation Guide Guide to Fan Noise and Vibration
pecification of Requirements for JallJral Smoke and Heal Exhausl Ventilators
pecification for Powered Smoke and Heat Exhaust Ventilators
Specification of Requirements for Smoke Curtains Design Gujue of Smoke Ventilation for Single Storey Lodustrilll Building~
Including those with Mezzanine Floor and IIi Racked Storage Warehou es - Issue 3
Guidance for the Design of Smoke entilation YSlem for Covered and Undergrollnd Car Parks - lssue 1
Application of SOloke Control Equipment and Syst m Guid to Good Practice - Isue J
58
DW154 Sp(C~tiifitiol for Plastics Ductwork
BRITISH STANDARDS INSTIT TION Sales Department 101 P ntooviLle Road London NI 9ND (felephone 020-78 1 78801)
CP 413 1973 Ducts for building ervices
SS 476 Fire tes on building matenals and lruc(ure
Part 4 19 4 Non-combustibility lest or materials
Part 6 I Fire propagation lest for materials
Part 7 1993 Surface spread of tlarnJ tesls for materia
Part 20 1987 Fir resistance of elements of construction
Part 21 1987 Fire r sistlUlce of loadbeanng elements of construction
Part 22 1987 Fhe istallceofllon-loadbearing elemcllts ofconsttuclion Part 23 1987 Contribution of componcnts to the fire resistance 0 a
structure
Part 24t987 Fire resi lance of wl1lilation ductl
SS 5588 nan 919 0 Fire Precautions III thc desIgn and OOSlnJ lion of buildings
S 729 1971 Hot dip galvanized oatiugs (or irOIl aod stcel articles
BS 1449 Steel plate sheet and Irip
Pan 11991 Carbon steel plate heel and strip Part 2 1983 Stainless steel plate sheer and strip
and
B middotENJOI49-2 996 BSEN 10149- 1991)
BSEN 10131 1992
BSEN22063 Sprayed metal coarings 1994 Protection of iron and steel by aluminium and zinc against
atmospheric cOlosion Irotectiotl of iron and ste I against corro ion and oxishydation at elevared temperatures
BS 353 1981 Glossary of lerms relnting to thermal insulation
BS ISO 1479 Self-tapplngscrewsandmetallicdri c crew
B -lSO 7049
1994
B 4800 1989 Painl colour for building purposes B 4848 l0 rolled structural steel sections
Part4 1972 Equal and unequal angles BS 5422 1990 Specification for the use of therm illuating matcriulS
SS 5720 1979 ode of practice for mechanical veutilating and air C 11shy
dirionin bull in building
l3S PR 12814-1 Bend resting for plasric welds
SS PR 12814-2 Tensile testing for plastic welds
SS PR 13067 Appro altesting for plastic welds
BS PR EN I 100-] Vi ual in pection ofplaslic welds
SHEET METAL AND AIR CONDITIONING CONTR-CTORS NATIONAL ASSOCIATION INC (SMACNA) Headquarters 420 I Lafayeue Center Drive Chanlilly Virginia 2051-1209
Mailing Address pa Box 221230 Cbantilly Virginilt120 153-1230
Telephone (703) 803-2980 Fax (703) 803-3732
Accepted IJJdustry Pl3Gtice for Industrial Duct Constnlelion 197 ) i-rchitecmral Sheet kwl Manual ([993)
Comractors Guide lor Modification 10 ooslruerion Colllraets 1993 Ducted Eleclric Heat Guide for ir Handling Ssrerns (1994)
En~rgy ollservatioD Guidelines (1984) Energy Recovery Equipment yslClllS (199l
Fibrou GIns Duct onS1ntClion Standards (1992)
Fire Smoke amp Radiation Damper In tall Guide for HVA Syst ms (1992) Guide t leel Stack 1(95)
HVA Air Duct Leakage Test Manual (19 ) HVA COlllmissioning lvlanual (1994)
H A Duct Construction Standards-Metal amp Flexible (1995) Addendum 01 (Nov 1997)
HVA Duct Systems Inspection Guide (1989)
HVA ySlems-Application (1986) nVAC ByternS-DLlct D ign (1990)
HVi Systems-Testing Adjusting amp Balancing (1993)
indoor Air Quality Manual (1993) tcheu quipment Fabrication Guidelmes (1990)
Managers Guide for elding (1993)
Rectangular Industrial Duct Cons1TUction Standards (19 0) Round Industrial Duct oustmction Standards (1977)
Sei mic Restraint Manual (1991) (wl Appendix E 1993) SMACNA Ma le Index ()fTechnical Publications (1995) Tbennoplnstic Duct CPY ) Construction Manual 1994)
DEPARTME OF THE ENVIRO MENT (Publications Centre) H Stationery Oflice 5 Nine Elms Lane London SWS 5DR
MampEJ 011972 Electrical in tallat1011 in buildings ( ew Editiou)
IampE 0319 Healing hot and cold wat r steam and gas losla1lations for buildings
M amp - No4 1970 Central heating and hot and cold ~ ateT in tallations for
dwelling
M amp ENo100 1971 Mechanical ventilation for building~
ASSOCIATION FOR SPECIALIST FIRE PROTECTlO As ociation House 235 Ash Road AJdershot Hampshire GUl2 4DD
Telephone OJ25221322 Fax 0 J252 333901
lublicalioos Fire Ratcd and moke Outlet Ducrwork An Industry Guide t Design and InSlalla lioll
HEALTH AND SAFETY EXEC TIVE Rose Court 2 Southwark Bridge London SEl 9HS Telephone 020-7717 6000
TWJ THE WELD G TlTUTE Abington Hall Abington Cambridge CB16AL Telepbone 0 J223 89162
Publication DatJ Oil w~ldll1g of lhermopla lics
59
DW154 wciiwlioll for Plastics Ductwork
A -=--DIX
Factors
Specific gravity shy pp = 091 approx UPVC = 14 approx
Some miscellaneous conversion factors
To convert
Length Inches to millimetres Feet to metres
Multiply by
2540 03048
To convert
Millimetres to inches Metres to feet
vIultiply by
003937 3281
Area Square inches to square millimetres 6452 Square millimetres to square inches 000155 Square feet to square metres 00929 Square metres to square feet 10764
Volume Cubic feet to cubic metres Cubic feet to litres Gallons (UK) to litres
002832 2831 4546
Cubic metres to cubic feet Litres to cubic feet Litres to gallons (UK)
35315 00353
022
Mass Ounces to grams Pounds to kiJograms Tons to tonnes
2835 04536
1016
Grams to ounces Kilograms to pounds Tonnes to tons
003527 2205
09842
Volume flow Cubic feet per minute to cubic Cubic metres per second to cubic
metres per second 0000472 feet per minute 2119 Cubic feet per mIDute to litres Litres per second to cubic feet
per second 04719 per minute 2119
Motion Feet per minute to metres per second 000508 Metres per second to feet per minute 197
Pressure Inches water gauge to millibars 2491 Inches wateJ- gauge to pascals (Pa) 2491 I Pa = I ewton per square metre = 10-2 millibars
60
Heating and Ventilating Contractors Association Esca House 34 Palace Court London W2 4JG
Tel 020 7313 4900
e-mail contact Itvcaorguk web site wwwhvcaorguk
Fax 020 7727 9268
DW154 SpecUicatoll for Plastics Ductwork
STANDARD COMPONE T DRAWINGS - PLA TEQUIPMENTIMISCELLANEOU
FIG DRAWING DETAILS
106 ~~~ Rectangular Attenuator
107 ~- Circular Attenuator
108
~ Beod Attenuator
109 J ~(f) Heating Coil
110 J ftte Cooling Coil
III Jc[ Electric Heating Coil
112 X F
Humidifier
113 [H XX Axial Fan
114 ~fB1famp Noo-standard Ductwork Cross hntchillg (of any separate type) indicates by reference to a key any non DVil54 ductwork system
115 2llIIIIJIIIIIll Flexible Ductwork
46
DW154 SJeCUicll(iol1 for Plastics Ductwork
TABLE 12 - STANDARD ABBREVIAT ONS
ABBREVIATION FLL
AD Acces Door
AFF Axial Flow Fan
AHU Air Handling nit
All Aluminium
AP Acess Panel
AT Attenuator
AV Air enninal Unit
BE 81ank nd
BQ Blast ate Damper
CC Cooling Coil
CF Centrifugal Fan
CTA Cross alk Attenuator
CVU Constant Volume Unit
DP Drain Point
EEC Electric Heating Coil
El Expansion Joint
FAl Fresh Air Inlet
FA From Above
FB From Belo
fBPP Fabric Backed Polypropyl-ne Sheet
Flexle Flexible Connection
lexfD Flexible Du t
C False Ceiling CO an oil Unit
fD Fire Damper
FFL Finished Floor Level
FJ Flanged Joint
FOAM Rigid Polyurethane Self xtinguishing Foam
FOB Flat on Bottom
FOT Flat on Top
GAM Galvanised after ManufacttrJc
GRP Glass Reinforced Plastic
GSS Galvanised Sheet Steel
HC Heating oil
HD and controlled Damper
HH Hand Hole
HL High Level
HVD High Velocity Discharge
IC Inspection Cover
ID lri Damper
IFS Intumescent Fircleevc
47
DW154 Specification for Plastics Ductwork
TABLE 12 - STANDAR ABBREVIATION CONTINUED
ABBREVIATION
IU
L
tv1D
MS
NRD NTS
OBO
OE
PHD
PD
PP
PP
PRD
PVC
RFC
RSC
R
SBO
SO
S1 TST
SSL
TA
TB
TO TJ
TP
TV
TV
OS
UPVC
S
V
VAV
50 RSA
FULL
Induction Unit
Low Level
Motor controlled Damper
Mjld Steel
on Return Damper
at to cale
Opposed Blade Damper
Open End
Parallel Blade Damper
Pneumatic controlled Damper
Polypropylene
Self xtinguishing Polypropylene
Pressure Relief Damper
Polyvinyl Chloride
Rolled Form Chamlel
Rolled Steel Channel
R fUnit
Singl Blade Damper
Smoke Damper
Slip Joint
Stainl t el
tructural Slab Level
To Ab vc
To Blow
Top Down (In Direction of Flow)
Telescopic Joint
Test Point
TU111iog Vane
Top Up (In Direction of Flo )
Voles Otherwise Stated
Unpl3sticisecl Polyvinyl Chloride
Underside
Ultra Violet Light
Variable Air Volume
Rolled Steel Angle (Vith Size)
48
DW154 SJeriiflllioll for Plastics Ductwork
A2 DUCT PRESSUREAPPE DXA Ductwork con truct d to DWIl54 will bebullbullbullbullbullbullbullbullbullbullbullbullbullbull
Air Leakage From Ductwork To be read in conjunction with DW143 A practical guide to Ductwork Leakage Testing
CAUTION As highlighted ill both this docul1lenr and DW14 I lot ellough emphasis can be placed 01 the fact that except for high pressure class C the much more stringent ductwork constructional standard brolght about b the general acceptance of DW154 have irtlally negated the requirement for leakage-testing It is essential lO realise lhat except where it is mandatory this doclllllelll is nOl an endors ~lIlent of the rourine testing of ducts bllt purely a guide to outline the procedures for cononnity with the air leakage limits ill Table l Where the specified methods of assembly and
A3sealing of dlcls are u ed a vi ual inspection wil ordinarily sl~fll e for ver(iatioll of a well engineered and a ceptahfy airtight COl1strucrioll WHERE NOT MANDATORY DUCT LEAKAGE TESTING IS GENERALLY AN UNJUSTIFIED AND SUBSTANTIAL EXPENSE
A1 INTRODUCTION L akage from ducted air distribution systems is an Lmportant consideration in the design and operation of ventilatjon and air conditioning middotystems A ductviork t)ystem tbat ba limited air leakag within defiucd limits wiH cnsUft
that tile design characteristics of the sytem can be maintained It wilJ also ensure that energy and operatLonal cosb are maintained at optimum levels DucLwork constlucted and Ulstalled in accordance with DW154 should minimise a level of air leakage that it) appropriate to tll operating static air pre sur in tile system
A4However it is recouuised that tbe environment in wtJich middotystems are installed is not always conducive to achieving a predictable level of quality in term of system ajr leakage and it is therefore accepted that designer may sometimes require tlle ystem to be tested in part or in total It should be ecogni ed that the testing of duct systems add a ignificant cost to the installation and incur some extra tjm within the programme (Se 47 and 64 re mandatory te-sting)
manufactured to a structural standard that is compatible with the system operating pressure There are three classes of duct con truction to eorre pond with the three pre ure clas meations Class A Lo pressure ducts suita le for a maximum positive operating pressure of 500 Pascal and a maximum negative pressure of -500 Pascals Class B IVledium pressure ductmiddot suitable for a rnaxilnuJJl positive operafjn o pressure of 1000 Pascals and a maxllnum negative pre sure of -750 Pa cal Class C High pre sure ducts suitable for a maximum po ilive operating pressur of 2000 Pa cals and a maximum negativ pres ur of -750 Paltcals
LEAKAGE FROM DUCTWORK Leakao-e front pia tic air ducts occur at the joint~ and is therefore proportional to the total surface area orthe du twork in th system Tb level of leakage i imilarly related to tIle air pres ure in th du t system and whilst there LS n precis formula for calculating the level of air los it i generally accepted that leakage will increase in proportjon to pressure to rbe pOvver of 065 The effect of air leakage from high pressure velocit ductwork is critical tn terms of system perfomlan dege energy consumption and the risk of high frequency noise as ociated with leakage These problems are le critical with medium pressure 10 ity systems but should be con idered Low pres mevelocity ducts present the lowe~t
ri k in tenn of tbe effect of leakage on the operation of the s stern
SYSTEM LEAKAGE LOSS As there i no di ct relatLonship between th volume of air conv yed and the surface area f the ductwork sy tern required to match the building configuratmn it is difficult to express air leakage a a percentage of total air volume Similarly the operating pressure will vary throughollt lh 3 system and a leakage is related to pre me the calculations ar comple However it is generally ac epted tbat in typical good quaJjty systems the leakage from
49
DW154 Specificatioll for Plastics Ductwork
each class of duct llnd r operating condition will be io the region of CIa S A low pressure 6 Clas B medium pres un 3 Clas C high pressure 2
A5 SPECIFYING AIR LEAKAGE TESTING Re peeting both the co -t and programme implications a sociated with te ling du 1 for leakage the designer may for example indicate that a particular system is te ted as follow
a) High pressure ducts - all tested b) Medium pr ssure duets - 10 of the
ductwork shall be s eet d at random and tested
c) Low pre sure - unte ed In any case where a random te t i elected for medium pre sure ductmiddot the followin c1au~e is suggested for inclusion by the de ign r
The designer hall elect at random a maxirnwlI of 10 of the dUCl system to bt tested for air leakage The duct hall be tested af the pressure recommended in Table J3 for the assifi atiol for the ectiol1 of the ductwork that is to be tested The tests shall be carried Ollt as the work proceeds and prior to the application of thermal insulation In the event of test failure of the randomlY selected section the designer shall have The right to select two La1her e tiolls at random for resting Where succes ive failures are identified there shall be a Tight to require rhl COl11raCWr 10 apply remedial attention to the complete ductwork system Th contractor shall provide documented eviden e of the calculalions used to arrive (1
the allowable 10 I for the section to be tested and the client or his agent shall willess and sign the results of the test
able 13 Air leakage rates
Maximum leakage of duct work Static
prcssUft Low-pressure edium-prc-sure I Iigh-prebull me diJfercntial Class A Class B Class C
1 2 J 4 Pa Litres per second per quare metre of surface area 100 054 018 ZOO 084 028 300 110 037 400 132 044 500 153 051 600 058 019 700 064 021 800 069 023 900 075 025
1000 080 027 1100 1200 1300 1400 1500
029 030 032 033 035
1600 1700 1800 1900 2000
036 038 039 040 042
Note Recommend d mean test presures are highlighted iD bold type with the actual selection being left to tll test operator
50
DW154 Sfeeiieaioll for Plastics Ductwork
A9
A10
and air leakage classification for the y em under test
DESIGNERS CALCULATIONS The designer can middotaJculate with reasonable accuracy the predicted total loss from a ystem by
a) Calculating the operatin presure in each ection of the sy tern
b) Calculating the surface area of the ductwork in each correspondin pre lire s ction
c) Calulating the allowabl~ los at the operating pressure for each ection of the system (see table 13 for allowable leakage figures)
VARIABLE PRESSUR S IN SYSTEMS De igner can achieve significant co t saving by matchina operating pressures throughout the system to constmctional standard and appropriate air leakage testing eO the practice of specifying construction tandards for whole duct sy tems based on fan discharge pre sure may incur unnece sary costs on a project For example ome large sy terns ould well be classiC ed for I akage limits as follows
Plant room risers CJas C Main floor distriblltJou CIa B Low pre sure outlets Cla A
A6 SPECIAL CASES There may be ~itLlations on a project where circumstance dictate thal pecial consideration be given to containing air loss s eg a long mn of duclwork may incur a di -proportjonate level of air 10 s In ca es such as thi example the designer can specify an improved tandard of airtighmess ie 80 of alJo~able 10 s for la B Ju ts The designer sbould not specif a CIa C t sI at CIa s C pressure for a CIa s B ducl
A7 SUGG S ED RANGE OF TES ING
A8 TESTING OF PLANT ITEMS Items of inline pJant (eg Fig 106 to 115) will not normaUy be included in an air I akage test The dllctwork contractor may indud such itelllS in tbe te t jf rh quipm ot has a certificate of COnfOlnlity for Ihe pres ure clas
bull High pressure duct bull Medium pre sure ducts bull Low pre sur ducts bull Exposed extract syst ID bull Ceiling void extract
systems bull Secondary ducts from
VAV or fan coil units bull Flexjble duct bull Final connections and
branches to grille and diffusers
100 test See A5 Untested UDt sted
Untested
Untested Untested
Untested
SI
i
DW154 SJecijicafion for Plastics Ductwork
ig 116 Permitted leakage at various pressures
Leakage in litres per second per square metre duct surface area
Vgt
o ltgt 0 ltgt N
ltgt Cgt
0 0 cc
0 0
~
g =
g ~
c 0
J
ltgt 0 I
~ ] tn
ltgt ltgt
In ol
~ 0 ~ 8 ~
~
c ltgt ltgt
~ CJ
~ ~ ~ ~ 8
0shyij
~ ~ ~ t
ltgt ltgt 00
l
~
~ Q
c C
~ rshy
e ltgt
I 1
I Cgt ltgtv
c Co ~
~~ ~ 10
I
0 Cgt
fJshyq 410 ) 1 ltgt
ltgt N
~ shy ltgt ltgt
~ I 1
c
52
DW154 Specificatio for Plastics Ductwork
Example of a completed test sheet Test No
General
Name of job N~ jC43Pt(r2lef Building Repound ~(~~0
Part 1 - Physical details
a Section of duct work to be tested ~(diffPIfff~el1f3rd Floor
b Drawing Number g91~~ c ssure aSSJ L atlOn V~Jl~IRfYgtg~~lPre Cl T Class C
d Test static pressure -(9 raErq~ ~~~~-~~J~~~ ~~ ~~~~ll
Leakaoe factor 9~-tre3$ecMz I OM REFTOTABLE 13)e b bullbullbullbullbullbullbull
f Surface area of duct under test Q~tJJItetre$ CPROMCALCU TIO BELOW)bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull ampampamp bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull
g ]Vlaxi mum permitted leakage -~ (~i~~0 ~~r~~ ~~~l-~-11~ ~~~Q
Part 2 - Test particulars
a Duct static pressure reading 9QFt~q~ ~ middot~~~1 ~~
b Manufacturer and type of liow measuring d vice (-~~~cJ~Y-9Q7EYg c Range of measurement of now measuring device QtP)OQ~(e~~~0I~~~~1~I~ ~~~~~~W~
d Reading of flm measurin o device pmiddot IFROM RIO)ftscag ~
I (DERlVED [ROM CHART SUPPUED WITH RIG US 0 ud)1e Interpreted air flow leakage rate ~(~~~f~~~ (~l~~~~~~~~~~~~~~~~~I
f Duration ~~~~~norn~allY l~ lnil1Ut~~d~~~ it1~ W~ Date of test ~(lITled ut by Wltll s ed by ~ ~
(~lJ MIJLrr) (Si~rrfltJUYJ
Printed Name 1~g0f~ Printed Name ~~Y~9~ and Company 7jl~~~~~( UJd CompanY AB COII$Itallt8
Width and depth or diameter
Periphery ength Area
millimetreS millimetres metre qL1are metre
800 x 750 3100 1755 5440
600 x 650 2500 557 1193
300 x 300 1200 120 144
305 din 958 700 670
250 dia 785 450 353
TOTAL 8000
53
DW154 Specijilarion for Plastics Ductwork
pA XB
Guida ce No es For he ransport Handling and
Storage of uctwork
avoid damage to adjacent duct panels In somc ca es particularly on con acts calling f r repetitive sizes the use of timber jigs and spacers may be justified Where reduced bulk and greater protection are major factor such as consignments for export transporting ductwork in L shape sections may justify the increa ed ite as embly co ts
It is recommended that before a contract is finalised that consideration is given to the subject of site acces material handling and storage as tbcy havgt a strong influence on the cost efficiency of the overall activity of ductwOlk installation
B3 Handling To minilnise th risk of damage duct sections should be clearly identified and deliveries to site should be closely linked to the installation programme so as to avoid accumulation of
B1 Storage and Handling of Ra Material Material should be stored in suitably designed racking out of direct unJight Where possible the e racks should be metal to earth Edges of cut she t may be harp and protective gloves are advised Wearing teel toe-capped boots is recommended Most pIa tic sheet is manufactured with smootb mfaces andor is suppLied with protective coating Care must be taken to prevent accidental lippag of stacked materials Beiuoshy good electrical insulators the movement of stock unless earthed will allow the build up of stati All stock shapes are chemically stable at normal temperature Whil t some raw materials used in their manufacture may themselves pre ent a toxic hazard once incorporated into the lOck bape they no long r constitute such a hazard and no dermatitic bazard are known nor are any
unfiJied ductwork and minimise double handling It is important to recognise that ductwork panels joint and corners arc susceptible to damage and care must be taken wheu band ling such material through a site During handling individual item of duct work may be liable to light cross sectional deformation until thev become an integral pan of a completed ductwork system Whilst this may temporarily detract from its intended appearance thi deformation will not have any detrimental effect on the functionality of the finally a semblecl system Installation of duct work and asociated plant items ill illevitably involve manual handUng The responsibi Iiry of employers and employees to a ses the risk of personal injury during mallual handling operations is et out in the HS E publication L23 Guidance on Manual Handling Regulations 1992
environmental problems expected 84 Site storage
B2 fransport Large capacity vehicles with high-sided open or closed-top bodies are tlle mo t suitable for the transport of dllctwork Careful consideration should be given to the
Adequate floor space IDust be provided within tbe building for the site storage of ductvork Such storage shalt make due allowance for thc stOf(ne of ductwork in stacks such that access ~ egt
between them is of sufficient width to pennil the removal of item without interference to
unloading of transport on sit a not all siJes b n fit from the material handlino- and access facilities that exi [ in a manufacturing workshop such as crane- fork-lifts or loading bay Site handJiog facilities along with
adjoining sta ks Ductvork components should be positioned so a to avoid crushing Ductwork of small panel size may be stored horizontally however care should be exercised to ensure that tack sizes are limited 10 within
ehicular acce s restrictions may itilluence the type and ize of transport to be uWised
engtlls of ductwork should be positioned 0
the tmctural strength of the duct sections to prevent distortion of the lower sections within the stack
as to avoid crushing Lengths Witll projections such as branches and bends i1anges girths damper quadrauL should be loaded so as to
54
DW154 S1tciic(ltioll for Plastics Ductwork
85 Internal cleanliness of new ductwork The site storage of ductwork introduces the important cODsideration of maintaining the internal cleanliness of the ductwork R feren e should be made to HVCA documentshybull DWffM2 Guide to Good Practice - internal
Cleanliness of New Ductwork Installations If the above conditioDs can not be satisfied consideration should be given by tJle designer to amending the specification to include for Po t Installation Cleaning as covered by tJ1C HVCA documentshybull TRJ17 Guide to Good Practic - Cleanliness
of Ventilation Systems
APPE DIXC
Fi e Retardant inishes C1 Improvement in the fire retardancy of plastic
ducts can be achieved to varying degrees and is wholly dependent llPOll the surface coating laminating resin selected and construction specification adopted In some instances smoke emission is coILSidered equaUy with other speci fication requirernen ts of the materials resistance to ignition and bumjng It is therefore important for design rs to establ ish the clients and officers detailed requirements and not rely on a tbird party interpretation of fire resisting or fire retardant Where possible the specification should refer dir etly to compliance with a British or European Standard identifying the specific sections applicable There are various types of resin and mat rcLnforcements that can achieve a Class 1 surface spread of flame ratin o when tested according to BS476 Part 7 (1987) This test puts materials illto Class I - 4 in descending order of perfoDllance according to the rat and extent of flame spread over their surfac under standard beating conditions Materials should also be tested for flre propagarion to BS476 Part 6 (1989) Tbi tesr measures the amount and rate of heat evolved by the material when subjected to standard heating
conditions Test results are given as an index of Perfonnance (i) whicb is based on three sub indices (iJ (i1) (h) The higher the value of the Index of Performance (i) the greater is the material s contribution to fire growth The higher the value of the sub-index 0) rhe greater the ease of ignition aod flame spread The highest product performance classification as defined in Approved Document B of the Building Regulations is Class O This is acLlieved if a material surface of a composite ploduct i~ either a) composed throughout of materials of
limited combustibility or b) a Class I material which has a tlre
propagation index (i) of not more than 12 and sub-index (i l ) of nor more than 6
01 J Class 0 is not a cla$sif1cation identified in any British Standard test
There are resin system reported to be classified to Class O when tested to BS476 Pcl1S 6 and 7 however designers need to ensure that such sysrems can be applied to their proposed design In propriety resinmat system available the fabrication techniques and COITect application are critical to the integrity of the reinforcing and clas ificatiol1 For example in some systems the u e of a non-fire retardant gelcont on a fire retardant substrate would reduce the classification For further information see HVCA publication DW144 Appendix D
55
DW154 SplCijiClIliol1 for Plastics Ductwork
x Guidance otes For nspectmiddoton Servicing a d
Clean-ng Access Openings
D1 GE ERAL This appendix highlight in ummary fOI111
the acce considerations that hould be made by the design r iD terms of inspection servicing and cleaning Having considered the seop and the design of the dUCI work system relative to the guidelines outlined below the designer should clearly indicate which levels of acces should be incorporated into the manufacture of a new duct work system (See Table 14 and Note I b low it
D2 DESIGN CONSIDERATIONS
D21 In ptction and servicing requireshyments are set out in Section 15 of Lhis specification
D22 Cleaning requirements are set out in the HVCA pubUcation TRl7 Guide to Good Practice Clean Lines of Ventilation Systems and the guide tates The precise location ize and
type of access would be dependent on the type of ductwork cleaning inspection and te ting metbods to b adopted Care protection and standards of cleanliness prior LO cOlllmisionin o
are set out in th AV A publication DWITM2 Guide to Good Practice Internal Cleanliness of New Ductwork Installations and th guide state Wh re specific limits of cleanliness are required ductwork sball be cleaned after installation by a spcialist cleaning contractor It will b in the interests of tht desioner botb financially and practically to cunsider employing a specialist c1eauing contractor at tbe
outset of a contract to internally clean newly installed ductwork prior to bandover This approach would reali e the following benefit shyi) Tb actual numb r of cleaning
access panels could be detennined to suit the method of cleaning to be adopted (This may be 1 s than the maximum requiremen listed under Lev 13 of Table 14)
ii) Clear directions could b given to the ductwork contractor as to tJle size and location of cleaning access panels that are required to be fitted during the mauushyfaclunng pro s
iii) The specialist cleaning operation prior to commi ioning vould enable the cleaning contractor to verify the practical acee requirement for the future cleaning operation associated -vitb a regular maintenance programme
iv) A specialist cleaning operation prior to commissioning would allow the designer to omit from the speeilicatiolJ the DWrrM2 requirem nt for factory sealing protection wipe downs and capping-off
v) Specialist Ieall ill 0 to the measurable standard defin d in TR17 will allow an objective definition of cleanline to be achieved
Car ful consideration must be gIven by the designer to the practl aJ problems associated witb the manufacture and fitting of suitably si Led access panel on small cross section duct and on the circular faces of rouod and flat oval ducts in particular
D23 Special con ideration must be given by the de igner to the practical problems associated with gaining personnel access to heavily congested ceiling areas and multi-la red du twork systems This approach would avoid
56
DW154 Spfciication for Plastics Ductwork
the possibility of access panels being D3 ACCESS 0 IN-LINE EQUIPMENT incorporated into a ductwork system at the This appendix unly covers acc il1spection manufacturing stage that were later found in through the ductwork body adjacent to an item practice to be inaccessible for either ervicing of in-line equipment and not openings in the or cleaning activities equipment itself
able 14 Acce requirements for inspection servicing and cleaning
HVCA PUBLICATIO REFE NeE (uidtgt 10 Gund Prartict
Adjace t OW144 Cleanliness orVcnlillltio S~lcr~ fRjJ7
in-line LeyeJ 1 Level 2 Level 3 ite sequipment pcdionSen lcin~ Section d C1eaniJl( SUn(O)lnspc lion Palle ltk~m_n
2011 (minimum OiL Jubje-ct to duct ~zel (ft~ -Panels
Control Da pcrs One (inspection) 203 One 300 mm x 200 mm Both sid Fire Dampers One (sCTjdJl~) 20211 One 300 0101 x 200 mm One side HeatingCooling Coils One (inspedion) 20213 One 300 mm x 200 mm (lIpstream) Both sides Attenuators (rectangular) None required One 300 mm x 200 mm (downstream) Both sides Attenuators (circular) one retluired One 300 mm x 200 mm (downstream) One side Filter Sections One (inspection) 20212 one required Uoth sides Air Turn Vanes None requjred None required Both sides Changes of Direction None required one required One side In-Duct FansDevices One (inspection) 20213 None required Both sides l
1 In the absence of any indication by the designer only Level ) access will be jncorporated into a new ductwork system
2 Tbe panel izes associated with Lev lis I and 3 acee s ar e middottablished by reference to Section 20 of DW144 and Section 2 ofTRll7 respectively
57
DW154 Speclfifatio for Plastics Ductwork
pA XE
B-bliography Included in this Bibliography are technical pUblications which may be of interest (0 ductwork designers fabricators and erectors and to tho e in the heating ventilatlng air conditioning industries generally nquiric should be made of the relevant organisation at the address quoted Since its publication other addresse contained within 0V154 mav have changed and some pubJicalions may have been superseded
HEATING AND VENTILATING CONTRACTORS ASSOCIATION
4 Palace Court London W2 4JG Telephone 020-7229 2488 Fax 020-7727 9268
Orders fo FlY A Publications Old Matlsion House Eamont Bridge Penrith Cumbria CA 10 2BX (Telephone 01768 864771 Fax 01768 86718) Email hvcapoblicationshvwelfarecouk DWn 44 pe ilicatiun for sheet mctal duclwork (Iow- mediulllshy
and high-pressure) 1998) DWIl4 A practical guide to dUGI ork I akage te ting
(revised 2000) DWII54 Specification for plastic~ duct rk DW171 Guide to good Practice for kitchen venlibtion system DW191 Guide to good pracuce glass fibre ductwoJk DwrrMI Acceptance cheme for new products - Redangolar cro
joint classification Guide to good pra tice - Internal cleanliness of new ductwork installations Guide to good practice for the design for the Installation of lire and smoke uampers
J 1Other puhlications
HampV safely guide 5th edition JS2 Tool box talks JS5 Weldlng Safety booklet JSI9 afety facts bo klet Fact sheets 1-24 2nd edition JS2J COSHH manual volume 1 Advice on compliance with the
regulations 1521A CO I-rH manual volume 2 Asses mcnt h ets JS23 Ri k management manual TR3 BrazinltT and bronze welding of copper pipework cUld sheet
(I 976) TR5 Welding of carbon steel pipework (1980)
TR6 Guide to Good Practice for Site Pre sure Testing of Pipework (19 0) Guide to good practice cleanliness of ventilation Ylem
CHARTERED IN TITUTlO OF BUILDING SERVICES E G EERS Delta House 222 Balham High Road London SW12 9BS rTelephone 020-8675 5211 Fax 020-8675 5449) CIBSE Guide Volume A Design Data Volume B In tallatiol1 and quipment Data Volume C Reference Data
CommlssioniJIg Codes These Codes eover the preliminary checkS eUing to work and regulation of vanous catcgories 0 plan The Codes give a guide to design implications Series A Air Distnbution Systems Series B Boiler Plant
ri s C Automatic Conlrol ystems Cr1es R Refrigerating Sy terns
Sene iN Water Distribution Systems
Technkal Memonllda TM 4 Design Notes for the Middle East TM bull Design otes for Ductwork TM 13 Minimi iog lhc Risk of egiounaires Disease
Research Reports RROI95 Ventilation system hygiene - A review of published
infomlatioo on lhe occurrence and ffects of Olltamination Rl~02J95 Air-to-air heal rec v ry RR0395 rnfluen e of HV C on smoke detectors
ATlONAL ENI [ERING SPECIFICATION LfMITED Southgatc hamber 3739 Southgate Street Winchester S023 9EH (Telephone 01962 842058 Fax 01962 R(8982) BUfLDING S RVICES RESEARCH AND [ ORMATION ASSOCIATIO Old Bracknell Lane West Bracknell Berkshire RG 12 4AH (Telephone Brackl1eU (01344) 426511 Fax 01344 487 -7 )
Application Guides AGln4 De tglJing Vana~le Volume middotylans for KOOnl
iir Movement AG1I91 Commissioning of V Sylcms in Buildings 11 6194 Fire Dampers
B) 94 cntiJalion or KitcneTls
AG389 The Commls ionin of Air Systems In Buildmgs AH2192 Commissioning of Bern - A ~ode of Practice TN2417 I Fire Dampec il) Ventilating Ducl
BEATING VENTILATING A AIR CONDITION G MA UFACTURERS ASSOCIATIO (HEVAC) HEVAC Henley Road Medmenham Marlow Buck SU 2ER (Telephone 01491 578674 ox 01491 575024 Emoimiddot infofetacouk)
Publicatjons Air Diffusion Guide Guide to Air Handling Unit Leakage Testing Guide to Good Practice Air Handling Unit Real Room Acoustic ~ st Procedure Specification for the ertiiicatioll ofAir Filters Method of Test for Water Rejection PerfOnTlatce of Louvrcs Subjected 1(1
Simulated Rainfall Test Procedure for Acoustic Loo cs Specification 10 Floor GrilJes - Types Performan e and Method ofTest Specification for the Determination of the Collection Efficiency of SilJ1d
Trap Louvre Domestic Mechwlical Vclltllalion Systems with Heal Recovery Fan Application Guid
~an and Ouctwork Installation Guide Guide to Fan Noise and Vibration
pecification of Requirements for JallJral Smoke and Heal Exhausl Ventilators
pecification for Powered Smoke and Heat Exhaust Ventilators
Specification of Requirements for Smoke Curtains Design Gujue of Smoke Ventilation for Single Storey Lodustrilll Building~
Including those with Mezzanine Floor and IIi Racked Storage Warehou es - Issue 3
Guidance for the Design of Smoke entilation YSlem for Covered and Undergrollnd Car Parks - lssue 1
Application of SOloke Control Equipment and Syst m Guid to Good Practice - Isue J
58
DW154 Sp(C~tiifitiol for Plastics Ductwork
BRITISH STANDARDS INSTIT TION Sales Department 101 P ntooviLle Road London NI 9ND (felephone 020-78 1 78801)
CP 413 1973 Ducts for building ervices
SS 476 Fire tes on building matenals and lruc(ure
Part 4 19 4 Non-combustibility lest or materials
Part 6 I Fire propagation lest for materials
Part 7 1993 Surface spread of tlarnJ tesls for materia
Part 20 1987 Fir resistance of elements of construction
Part 21 1987 Fire r sistlUlce of loadbeanng elements of construction
Part 22 1987 Fhe istallceofllon-loadbearing elemcllts ofconsttuclion Part 23 1987 Contribution of componcnts to the fire resistance 0 a
structure
Part 24t987 Fire resi lance of wl1lilation ductl
SS 5588 nan 919 0 Fire Precautions III thc desIgn and OOSlnJ lion of buildings
S 729 1971 Hot dip galvanized oatiugs (or irOIl aod stcel articles
BS 1449 Steel plate sheet and Irip
Pan 11991 Carbon steel plate heel and strip Part 2 1983 Stainless steel plate sheer and strip
and
B middotENJOI49-2 996 BSEN 10149- 1991)
BSEN 10131 1992
BSEN22063 Sprayed metal coarings 1994 Protection of iron and steel by aluminium and zinc against
atmospheric cOlosion Irotectiotl of iron and ste I against corro ion and oxishydation at elevared temperatures
BS 353 1981 Glossary of lerms relnting to thermal insulation
BS ISO 1479 Self-tapplngscrewsandmetallicdri c crew
B -lSO 7049
1994
B 4800 1989 Painl colour for building purposes B 4848 l0 rolled structural steel sections
Part4 1972 Equal and unequal angles BS 5422 1990 Specification for the use of therm illuating matcriulS
SS 5720 1979 ode of practice for mechanical veutilating and air C 11shy
dirionin bull in building
l3S PR 12814-1 Bend resting for plasric welds
SS PR 12814-2 Tensile testing for plastic welds
SS PR 13067 Appro altesting for plastic welds
BS PR EN I 100-] Vi ual in pection ofplaslic welds
SHEET METAL AND AIR CONDITIONING CONTR-CTORS NATIONAL ASSOCIATION INC (SMACNA) Headquarters 420 I Lafayeue Center Drive Chanlilly Virginia 2051-1209
Mailing Address pa Box 221230 Cbantilly Virginilt120 153-1230
Telephone (703) 803-2980 Fax (703) 803-3732
Accepted IJJdustry Pl3Gtice for Industrial Duct Constnlelion 197 ) i-rchitecmral Sheet kwl Manual ([993)
Comractors Guide lor Modification 10 ooslruerion Colllraets 1993 Ducted Eleclric Heat Guide for ir Handling Ssrerns (1994)
En~rgy ollservatioD Guidelines (1984) Energy Recovery Equipment yslClllS (199l
Fibrou GIns Duct onS1ntClion Standards (1992)
Fire Smoke amp Radiation Damper In tall Guide for HVA Syst ms (1992) Guide t leel Stack 1(95)
HVA Air Duct Leakage Test Manual (19 ) HVA COlllmissioning lvlanual (1994)
H A Duct Construction Standards-Metal amp Flexible (1995) Addendum 01 (Nov 1997)
HVA Duct Systems Inspection Guide (1989)
HVA ySlems-Application (1986) nVAC ByternS-DLlct D ign (1990)
HVi Systems-Testing Adjusting amp Balancing (1993)
indoor Air Quality Manual (1993) tcheu quipment Fabrication Guidelmes (1990)
Managers Guide for elding (1993)
Rectangular Industrial Duct Cons1TUction Standards (19 0) Round Industrial Duct oustmction Standards (1977)
Sei mic Restraint Manual (1991) (wl Appendix E 1993) SMACNA Ma le Index ()fTechnical Publications (1995) Tbennoplnstic Duct CPY ) Construction Manual 1994)
DEPARTME OF THE ENVIRO MENT (Publications Centre) H Stationery Oflice 5 Nine Elms Lane London SWS 5DR
MampEJ 011972 Electrical in tallat1011 in buildings ( ew Editiou)
IampE 0319 Healing hot and cold wat r steam and gas losla1lations for buildings
M amp - No4 1970 Central heating and hot and cold ~ ateT in tallations for
dwelling
M amp ENo100 1971 Mechanical ventilation for building~
ASSOCIATION FOR SPECIALIST FIRE PROTECTlO As ociation House 235 Ash Road AJdershot Hampshire GUl2 4DD
Telephone OJ25221322 Fax 0 J252 333901
lublicalioos Fire Ratcd and moke Outlet Ducrwork An Industry Guide t Design and InSlalla lioll
HEALTH AND SAFETY EXEC TIVE Rose Court 2 Southwark Bridge London SEl 9HS Telephone 020-7717 6000
TWJ THE WELD G TlTUTE Abington Hall Abington Cambridge CB16AL Telepbone 0 J223 89162
Publication DatJ Oil w~ldll1g of lhermopla lics
59
DW154 wciiwlioll for Plastics Ductwork
A -=--DIX
Factors
Specific gravity shy pp = 091 approx UPVC = 14 approx
Some miscellaneous conversion factors
To convert
Length Inches to millimetres Feet to metres
Multiply by
2540 03048
To convert
Millimetres to inches Metres to feet
vIultiply by
003937 3281
Area Square inches to square millimetres 6452 Square millimetres to square inches 000155 Square feet to square metres 00929 Square metres to square feet 10764
Volume Cubic feet to cubic metres Cubic feet to litres Gallons (UK) to litres
002832 2831 4546
Cubic metres to cubic feet Litres to cubic feet Litres to gallons (UK)
35315 00353
022
Mass Ounces to grams Pounds to kiJograms Tons to tonnes
2835 04536
1016
Grams to ounces Kilograms to pounds Tonnes to tons
003527 2205
09842
Volume flow Cubic feet per minute to cubic Cubic metres per second to cubic
metres per second 0000472 feet per minute 2119 Cubic feet per mIDute to litres Litres per second to cubic feet
per second 04719 per minute 2119
Motion Feet per minute to metres per second 000508 Metres per second to feet per minute 197
Pressure Inches water gauge to millibars 2491 Inches wateJ- gauge to pascals (Pa) 2491 I Pa = I ewton per square metre = 10-2 millibars
60
Heating and Ventilating Contractors Association Esca House 34 Palace Court London W2 4JG
Tel 020 7313 4900
e-mail contact Itvcaorguk web site wwwhvcaorguk
Fax 020 7727 9268
DW154 SJeCUicll(iol1 for Plastics Ductwork
TABLE 12 - STANDARD ABBREVIAT ONS
ABBREVIATION FLL
AD Acces Door
AFF Axial Flow Fan
AHU Air Handling nit
All Aluminium
AP Acess Panel
AT Attenuator
AV Air enninal Unit
BE 81ank nd
BQ Blast ate Damper
CC Cooling Coil
CF Centrifugal Fan
CTA Cross alk Attenuator
CVU Constant Volume Unit
DP Drain Point
EEC Electric Heating Coil
El Expansion Joint
FAl Fresh Air Inlet
FA From Above
FB From Belo
fBPP Fabric Backed Polypropyl-ne Sheet
Flexle Flexible Connection
lexfD Flexible Du t
C False Ceiling CO an oil Unit
fD Fire Damper
FFL Finished Floor Level
FJ Flanged Joint
FOAM Rigid Polyurethane Self xtinguishing Foam
FOB Flat on Bottom
FOT Flat on Top
GAM Galvanised after ManufacttrJc
GRP Glass Reinforced Plastic
GSS Galvanised Sheet Steel
HC Heating oil
HD and controlled Damper
HH Hand Hole
HL High Level
HVD High Velocity Discharge
IC Inspection Cover
ID lri Damper
IFS Intumescent Fircleevc
47
DW154 Specification for Plastics Ductwork
TABLE 12 - STANDAR ABBREVIATION CONTINUED
ABBREVIATION
IU
L
tv1D
MS
NRD NTS
OBO
OE
PHD
PD
PP
PP
PRD
PVC
RFC
RSC
R
SBO
SO
S1 TST
SSL
TA
TB
TO TJ
TP
TV
TV
OS
UPVC
S
V
VAV
50 RSA
FULL
Induction Unit
Low Level
Motor controlled Damper
Mjld Steel
on Return Damper
at to cale
Opposed Blade Damper
Open End
Parallel Blade Damper
Pneumatic controlled Damper
Polypropylene
Self xtinguishing Polypropylene
Pressure Relief Damper
Polyvinyl Chloride
Rolled Form Chamlel
Rolled Steel Channel
R fUnit
Singl Blade Damper
Smoke Damper
Slip Joint
Stainl t el
tructural Slab Level
To Ab vc
To Blow
Top Down (In Direction of Flow)
Telescopic Joint
Test Point
TU111iog Vane
Top Up (In Direction of Flo )
Voles Otherwise Stated
Unpl3sticisecl Polyvinyl Chloride
Underside
Ultra Violet Light
Variable Air Volume
Rolled Steel Angle (Vith Size)
48
DW154 SJeriiflllioll for Plastics Ductwork
A2 DUCT PRESSUREAPPE DXA Ductwork con truct d to DWIl54 will bebullbullbullbullbullbullbullbullbullbullbullbullbullbull
Air Leakage From Ductwork To be read in conjunction with DW143 A practical guide to Ductwork Leakage Testing
CAUTION As highlighted ill both this docul1lenr and DW14 I lot ellough emphasis can be placed 01 the fact that except for high pressure class C the much more stringent ductwork constructional standard brolght about b the general acceptance of DW154 have irtlally negated the requirement for leakage-testing It is essential lO realise lhat except where it is mandatory this doclllllelll is nOl an endors ~lIlent of the rourine testing of ducts bllt purely a guide to outline the procedures for cononnity with the air leakage limits ill Table l Where the specified methods of assembly and
A3sealing of dlcls are u ed a vi ual inspection wil ordinarily sl~fll e for ver(iatioll of a well engineered and a ceptahfy airtight COl1strucrioll WHERE NOT MANDATORY DUCT LEAKAGE TESTING IS GENERALLY AN UNJUSTIFIED AND SUBSTANTIAL EXPENSE
A1 INTRODUCTION L akage from ducted air distribution systems is an Lmportant consideration in the design and operation of ventilatjon and air conditioning middotystems A ductviork t)ystem tbat ba limited air leakag within defiucd limits wiH cnsUft
that tile design characteristics of the sytem can be maintained It wilJ also ensure that energy and operatLonal cosb are maintained at optimum levels DucLwork constlucted and Ulstalled in accordance with DW154 should minimise a level of air leakage that it) appropriate to tll operating static air pre sur in tile system
A4However it is recouuised that tbe environment in wtJich middotystems are installed is not always conducive to achieving a predictable level of quality in term of system ajr leakage and it is therefore accepted that designer may sometimes require tlle ystem to be tested in part or in total It should be ecogni ed that the testing of duct systems add a ignificant cost to the installation and incur some extra tjm within the programme (Se 47 and 64 re mandatory te-sting)
manufactured to a structural standard that is compatible with the system operating pressure There are three classes of duct con truction to eorre pond with the three pre ure clas meations Class A Lo pressure ducts suita le for a maximum positive operating pressure of 500 Pascal and a maximum negative pressure of -500 Pascals Class B IVledium pressure ductmiddot suitable for a rnaxilnuJJl positive operafjn o pressure of 1000 Pascals and a maxllnum negative pre sure of -750 Pa cal Class C High pre sure ducts suitable for a maximum po ilive operating pressur of 2000 Pa cals and a maximum negativ pres ur of -750 Paltcals
LEAKAGE FROM DUCTWORK Leakao-e front pia tic air ducts occur at the joint~ and is therefore proportional to the total surface area orthe du twork in th system Tb level of leakage i imilarly related to tIle air pres ure in th du t system and whilst there LS n precis formula for calculating the level of air los it i generally accepted that leakage will increase in proportjon to pressure to rbe pOvver of 065 The effect of air leakage from high pressure velocit ductwork is critical tn terms of system perfomlan dege energy consumption and the risk of high frequency noise as ociated with leakage These problems are le critical with medium pressure 10 ity systems but should be con idered Low pres mevelocity ducts present the lowe~t
ri k in tenn of tbe effect of leakage on the operation of the s stern
SYSTEM LEAKAGE LOSS As there i no di ct relatLonship between th volume of air conv yed and the surface area f the ductwork sy tern required to match the building configuratmn it is difficult to express air leakage a a percentage of total air volume Similarly the operating pressure will vary throughollt lh 3 system and a leakage is related to pre me the calculations ar comple However it is generally ac epted tbat in typical good quaJjty systems the leakage from
49
DW154 Specificatioll for Plastics Ductwork
each class of duct llnd r operating condition will be io the region of CIa S A low pressure 6 Clas B medium pres un 3 Clas C high pressure 2
A5 SPECIFYING AIR LEAKAGE TESTING Re peeting both the co -t and programme implications a sociated with te ling du 1 for leakage the designer may for example indicate that a particular system is te ted as follow
a) High pressure ducts - all tested b) Medium pr ssure duets - 10 of the
ductwork shall be s eet d at random and tested
c) Low pre sure - unte ed In any case where a random te t i elected for medium pre sure ductmiddot the followin c1au~e is suggested for inclusion by the de ign r
The designer hall elect at random a maxirnwlI of 10 of the dUCl system to bt tested for air leakage The duct hall be tested af the pressure recommended in Table J3 for the assifi atiol for the ectiol1 of the ductwork that is to be tested The tests shall be carried Ollt as the work proceeds and prior to the application of thermal insulation In the event of test failure of the randomlY selected section the designer shall have The right to select two La1her e tiolls at random for resting Where succes ive failures are identified there shall be a Tight to require rhl COl11raCWr 10 apply remedial attention to the complete ductwork system Th contractor shall provide documented eviden e of the calculalions used to arrive (1
the allowable 10 I for the section to be tested and the client or his agent shall willess and sign the results of the test
able 13 Air leakage rates
Maximum leakage of duct work Static
prcssUft Low-pressure edium-prc-sure I Iigh-prebull me diJfercntial Class A Class B Class C
1 2 J 4 Pa Litres per second per quare metre of surface area 100 054 018 ZOO 084 028 300 110 037 400 132 044 500 153 051 600 058 019 700 064 021 800 069 023 900 075 025
1000 080 027 1100 1200 1300 1400 1500
029 030 032 033 035
1600 1700 1800 1900 2000
036 038 039 040 042
Note Recommend d mean test presures are highlighted iD bold type with the actual selection being left to tll test operator
50
DW154 Sfeeiieaioll for Plastics Ductwork
A9
A10
and air leakage classification for the y em under test
DESIGNERS CALCULATIONS The designer can middotaJculate with reasonable accuracy the predicted total loss from a ystem by
a) Calculating the operatin presure in each ection of the sy tern
b) Calculating the surface area of the ductwork in each correspondin pre lire s ction
c) Calulating the allowabl~ los at the operating pressure for each ection of the system (see table 13 for allowable leakage figures)
VARIABLE PRESSUR S IN SYSTEMS De igner can achieve significant co t saving by matchina operating pressures throughout the system to constmctional standard and appropriate air leakage testing eO the practice of specifying construction tandards for whole duct sy tems based on fan discharge pre sure may incur unnece sary costs on a project For example ome large sy terns ould well be classiC ed for I akage limits as follows
Plant room risers CJas C Main floor distriblltJou CIa B Low pre sure outlets Cla A
A6 SPECIAL CASES There may be ~itLlations on a project where circumstance dictate thal pecial consideration be given to containing air loss s eg a long mn of duclwork may incur a di -proportjonate level of air 10 s In ca es such as thi example the designer can specify an improved tandard of airtighmess ie 80 of alJo~able 10 s for la B Ju ts The designer sbould not specif a CIa C t sI at CIa s C pressure for a CIa s B ducl
A7 SUGG S ED RANGE OF TES ING
A8 TESTING OF PLANT ITEMS Items of inline pJant (eg Fig 106 to 115) will not normaUy be included in an air I akage test The dllctwork contractor may indud such itelllS in tbe te t jf rh quipm ot has a certificate of COnfOlnlity for Ihe pres ure clas
bull High pressure duct bull Medium pre sure ducts bull Low pre sur ducts bull Exposed extract syst ID bull Ceiling void extract
systems bull Secondary ducts from
VAV or fan coil units bull Flexjble duct bull Final connections and
branches to grille and diffusers
100 test See A5 Untested UDt sted
Untested
Untested Untested
Untested
SI
i
DW154 SJecijicafion for Plastics Ductwork
ig 116 Permitted leakage at various pressures
Leakage in litres per second per square metre duct surface area
Vgt
o ltgt 0 ltgt N
ltgt Cgt
0 0 cc
0 0
~
g =
g ~
c 0
J
ltgt 0 I
~ ] tn
ltgt ltgt
In ol
~ 0 ~ 8 ~
~
c ltgt ltgt
~ CJ
~ ~ ~ ~ 8
0shyij
~ ~ ~ t
ltgt ltgt 00
l
~
~ Q
c C
~ rshy
e ltgt
I 1
I Cgt ltgtv
c Co ~
~~ ~ 10
I
0 Cgt
fJshyq 410 ) 1 ltgt
ltgt N
~ shy ltgt ltgt
~ I 1
c
52
DW154 Specificatio for Plastics Ductwork
Example of a completed test sheet Test No
General
Name of job N~ jC43Pt(r2lef Building Repound ~(~~0
Part 1 - Physical details
a Section of duct work to be tested ~(diffPIfff~el1f3rd Floor
b Drawing Number g91~~ c ssure aSSJ L atlOn V~Jl~IRfYgtg~~lPre Cl T Class C
d Test static pressure -(9 raErq~ ~~~~-~~J~~~ ~~ ~~~~ll
Leakaoe factor 9~-tre3$ecMz I OM REFTOTABLE 13)e b bullbullbullbullbullbullbull
f Surface area of duct under test Q~tJJItetre$ CPROMCALCU TIO BELOW)bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull ampampamp bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull
g ]Vlaxi mum permitted leakage -~ (~i~~0 ~~r~~ ~~~l-~-11~ ~~~Q
Part 2 - Test particulars
a Duct static pressure reading 9QFt~q~ ~ middot~~~1 ~~
b Manufacturer and type of liow measuring d vice (-~~~cJ~Y-9Q7EYg c Range of measurement of now measuring device QtP)OQ~(e~~~0I~~~~1~I~ ~~~~~~W~
d Reading of flm measurin o device pmiddot IFROM RIO)ftscag ~
I (DERlVED [ROM CHART SUPPUED WITH RIG US 0 ud)1e Interpreted air flow leakage rate ~(~~~f~~~ (~l~~~~~~~~~~~~~~~~~I
f Duration ~~~~~norn~allY l~ lnil1Ut~~d~~~ it1~ W~ Date of test ~(lITled ut by Wltll s ed by ~ ~
(~lJ MIJLrr) (Si~rrfltJUYJ
Printed Name 1~g0f~ Printed Name ~~Y~9~ and Company 7jl~~~~~( UJd CompanY AB COII$Itallt8
Width and depth or diameter
Periphery ength Area
millimetreS millimetres metre qL1are metre
800 x 750 3100 1755 5440
600 x 650 2500 557 1193
300 x 300 1200 120 144
305 din 958 700 670
250 dia 785 450 353
TOTAL 8000
53
DW154 Specijilarion for Plastics Ductwork
pA XB
Guida ce No es For he ransport Handling and
Storage of uctwork
avoid damage to adjacent duct panels In somc ca es particularly on con acts calling f r repetitive sizes the use of timber jigs and spacers may be justified Where reduced bulk and greater protection are major factor such as consignments for export transporting ductwork in L shape sections may justify the increa ed ite as embly co ts
It is recommended that before a contract is finalised that consideration is given to the subject of site acces material handling and storage as tbcy havgt a strong influence on the cost efficiency of the overall activity of ductwOlk installation
B3 Handling To minilnise th risk of damage duct sections should be clearly identified and deliveries to site should be closely linked to the installation programme so as to avoid accumulation of
B1 Storage and Handling of Ra Material Material should be stored in suitably designed racking out of direct unJight Where possible the e racks should be metal to earth Edges of cut she t may be harp and protective gloves are advised Wearing teel toe-capped boots is recommended Most pIa tic sheet is manufactured with smootb mfaces andor is suppLied with protective coating Care must be taken to prevent accidental lippag of stacked materials Beiuoshy good electrical insulators the movement of stock unless earthed will allow the build up of stati All stock shapes are chemically stable at normal temperature Whil t some raw materials used in their manufacture may themselves pre ent a toxic hazard once incorporated into the lOck bape they no long r constitute such a hazard and no dermatitic bazard are known nor are any
unfiJied ductwork and minimise double handling It is important to recognise that ductwork panels joint and corners arc susceptible to damage and care must be taken wheu band ling such material through a site During handling individual item of duct work may be liable to light cross sectional deformation until thev become an integral pan of a completed ductwork system Whilst this may temporarily detract from its intended appearance thi deformation will not have any detrimental effect on the functionality of the finally a semblecl system Installation of duct work and asociated plant items ill illevitably involve manual handUng The responsibi Iiry of employers and employees to a ses the risk of personal injury during mallual handling operations is et out in the HS E publication L23 Guidance on Manual Handling Regulations 1992
environmental problems expected 84 Site storage
B2 fransport Large capacity vehicles with high-sided open or closed-top bodies are tlle mo t suitable for the transport of dllctwork Careful consideration should be given to the
Adequate floor space IDust be provided within tbe building for the site storage of ductvork Such storage shalt make due allowance for thc stOf(ne of ductwork in stacks such that access ~ egt
between them is of sufficient width to pennil the removal of item without interference to
unloading of transport on sit a not all siJes b n fit from the material handlino- and access facilities that exi [ in a manufacturing workshop such as crane- fork-lifts or loading bay Site handJiog facilities along with
adjoining sta ks Ductvork components should be positioned so a to avoid crushing Ductwork of small panel size may be stored horizontally however care should be exercised to ensure that tack sizes are limited 10 within
ehicular acce s restrictions may itilluence the type and ize of transport to be uWised
engtlls of ductwork should be positioned 0
the tmctural strength of the duct sections to prevent distortion of the lower sections within the stack
as to avoid crushing Lengths Witll projections such as branches and bends i1anges girths damper quadrauL should be loaded so as to
54
DW154 S1tciic(ltioll for Plastics Ductwork
85 Internal cleanliness of new ductwork The site storage of ductwork introduces the important cODsideration of maintaining the internal cleanliness of the ductwork R feren e should be made to HVCA documentshybull DWffM2 Guide to Good Practice - internal
Cleanliness of New Ductwork Installations If the above conditioDs can not be satisfied consideration should be given by tJle designer to amending the specification to include for Po t Installation Cleaning as covered by tJ1C HVCA documentshybull TRJ17 Guide to Good Practic - Cleanliness
of Ventilation Systems
APPE DIXC
Fi e Retardant inishes C1 Improvement in the fire retardancy of plastic
ducts can be achieved to varying degrees and is wholly dependent llPOll the surface coating laminating resin selected and construction specification adopted In some instances smoke emission is coILSidered equaUy with other speci fication requirernen ts of the materials resistance to ignition and bumjng It is therefore important for design rs to establ ish the clients and officers detailed requirements and not rely on a tbird party interpretation of fire resisting or fire retardant Where possible the specification should refer dir etly to compliance with a British or European Standard identifying the specific sections applicable There are various types of resin and mat rcLnforcements that can achieve a Class 1 surface spread of flame ratin o when tested according to BS476 Part 7 (1987) This test puts materials illto Class I - 4 in descending order of perfoDllance according to the rat and extent of flame spread over their surfac under standard beating conditions Materials should also be tested for flre propagarion to BS476 Part 6 (1989) Tbi tesr measures the amount and rate of heat evolved by the material when subjected to standard heating
conditions Test results are given as an index of Perfonnance (i) whicb is based on three sub indices (iJ (i1) (h) The higher the value of the Index of Performance (i) the greater is the material s contribution to fire growth The higher the value of the sub-index 0) rhe greater the ease of ignition aod flame spread The highest product performance classification as defined in Approved Document B of the Building Regulations is Class O This is acLlieved if a material surface of a composite ploduct i~ either a) composed throughout of materials of
limited combustibility or b) a Class I material which has a tlre
propagation index (i) of not more than 12 and sub-index (i l ) of nor more than 6
01 J Class 0 is not a cla$sif1cation identified in any British Standard test
There are resin system reported to be classified to Class O when tested to BS476 Pcl1S 6 and 7 however designers need to ensure that such sysrems can be applied to their proposed design In propriety resinmat system available the fabrication techniques and COITect application are critical to the integrity of the reinforcing and clas ificatiol1 For example in some systems the u e of a non-fire retardant gelcont on a fire retardant substrate would reduce the classification For further information see HVCA publication DW144 Appendix D
55
DW154 SplCijiClIliol1 for Plastics Ductwork
x Guidance otes For nspectmiddoton Servicing a d
Clean-ng Access Openings
D1 GE ERAL This appendix highlight in ummary fOI111
the acce considerations that hould be made by the design r iD terms of inspection servicing and cleaning Having considered the seop and the design of the dUCI work system relative to the guidelines outlined below the designer should clearly indicate which levels of acces should be incorporated into the manufacture of a new duct work system (See Table 14 and Note I b low it
D2 DESIGN CONSIDERATIONS
D21 In ptction and servicing requireshyments are set out in Section 15 of Lhis specification
D22 Cleaning requirements are set out in the HVCA pubUcation TRl7 Guide to Good Practice Clean Lines of Ventilation Systems and the guide tates The precise location ize and
type of access would be dependent on the type of ductwork cleaning inspection and te ting metbods to b adopted Care protection and standards of cleanliness prior LO cOlllmisionin o
are set out in th AV A publication DWITM2 Guide to Good Practice Internal Cleanliness of New Ductwork Installations and th guide state Wh re specific limits of cleanliness are required ductwork sball be cleaned after installation by a spcialist cleaning contractor It will b in the interests of tht desioner botb financially and practically to cunsider employing a specialist c1eauing contractor at tbe
outset of a contract to internally clean newly installed ductwork prior to bandover This approach would reali e the following benefit shyi) Tb actual numb r of cleaning
access panels could be detennined to suit the method of cleaning to be adopted (This may be 1 s than the maximum requiremen listed under Lev 13 of Table 14)
ii) Clear directions could b given to the ductwork contractor as to tJle size and location of cleaning access panels that are required to be fitted during the mauushyfaclunng pro s
iii) The specialist cleaning operation prior to commi ioning vould enable the cleaning contractor to verify the practical acee requirement for the future cleaning operation associated -vitb a regular maintenance programme
iv) A specialist cleaning operation prior to commissioning would allow the designer to omit from the speeilicatiolJ the DWrrM2 requirem nt for factory sealing protection wipe downs and capping-off
v) Specialist Ieall ill 0 to the measurable standard defin d in TR17 will allow an objective definition of cleanline to be achieved
Car ful consideration must be gIven by the designer to the practl aJ problems associated witb the manufacture and fitting of suitably si Led access panel on small cross section duct and on the circular faces of rouod and flat oval ducts in particular
D23 Special con ideration must be given by the de igner to the practical problems associated with gaining personnel access to heavily congested ceiling areas and multi-la red du twork systems This approach would avoid
56
DW154 Spfciication for Plastics Ductwork
the possibility of access panels being D3 ACCESS 0 IN-LINE EQUIPMENT incorporated into a ductwork system at the This appendix unly covers acc il1spection manufacturing stage that were later found in through the ductwork body adjacent to an item practice to be inaccessible for either ervicing of in-line equipment and not openings in the or cleaning activities equipment itself
able 14 Acce requirements for inspection servicing and cleaning
HVCA PUBLICATIO REFE NeE (uidtgt 10 Gund Prartict
Adjace t OW144 Cleanliness orVcnlillltio S~lcr~ fRjJ7
in-line LeyeJ 1 Level 2 Level 3 ite sequipment pcdionSen lcin~ Section d C1eaniJl( SUn(O)lnspc lion Palle ltk~m_n
2011 (minimum OiL Jubje-ct to duct ~zel (ft~ -Panels
Control Da pcrs One (inspection) 203 One 300 mm x 200 mm Both sid Fire Dampers One (sCTjdJl~) 20211 One 300 0101 x 200 mm One side HeatingCooling Coils One (inspedion) 20213 One 300 mm x 200 mm (lIpstream) Both sides Attenuators (rectangular) None required One 300 mm x 200 mm (downstream) Both sides Attenuators (circular) one retluired One 300 mm x 200 mm (downstream) One side Filter Sections One (inspection) 20212 one required Uoth sides Air Turn Vanes None requjred None required Both sides Changes of Direction None required one required One side In-Duct FansDevices One (inspection) 20213 None required Both sides l
1 In the absence of any indication by the designer only Level ) access will be jncorporated into a new ductwork system
2 Tbe panel izes associated with Lev lis I and 3 acee s ar e middottablished by reference to Section 20 of DW144 and Section 2 ofTRll7 respectively
57
DW154 Speclfifatio for Plastics Ductwork
pA XE
B-bliography Included in this Bibliography are technical pUblications which may be of interest (0 ductwork designers fabricators and erectors and to tho e in the heating ventilatlng air conditioning industries generally nquiric should be made of the relevant organisation at the address quoted Since its publication other addresse contained within 0V154 mav have changed and some pubJicalions may have been superseded
HEATING AND VENTILATING CONTRACTORS ASSOCIATION
4 Palace Court London W2 4JG Telephone 020-7229 2488 Fax 020-7727 9268
Orders fo FlY A Publications Old Matlsion House Eamont Bridge Penrith Cumbria CA 10 2BX (Telephone 01768 864771 Fax 01768 86718) Email hvcapoblicationshvwelfarecouk DWn 44 pe ilicatiun for sheet mctal duclwork (Iow- mediulllshy
and high-pressure) 1998) DWIl4 A practical guide to dUGI ork I akage te ting
(revised 2000) DWII54 Specification for plastic~ duct rk DW171 Guide to good Practice for kitchen venlibtion system DW191 Guide to good pracuce glass fibre ductwoJk DwrrMI Acceptance cheme for new products - Redangolar cro
joint classification Guide to good pra tice - Internal cleanliness of new ductwork installations Guide to good practice for the design for the Installation of lire and smoke uampers
J 1Other puhlications
HampV safely guide 5th edition JS2 Tool box talks JS5 Weldlng Safety booklet JSI9 afety facts bo klet Fact sheets 1-24 2nd edition JS2J COSHH manual volume 1 Advice on compliance with the
regulations 1521A CO I-rH manual volume 2 Asses mcnt h ets JS23 Ri k management manual TR3 BrazinltT and bronze welding of copper pipework cUld sheet
(I 976) TR5 Welding of carbon steel pipework (1980)
TR6 Guide to Good Practice for Site Pre sure Testing of Pipework (19 0) Guide to good practice cleanliness of ventilation Ylem
CHARTERED IN TITUTlO OF BUILDING SERVICES E G EERS Delta House 222 Balham High Road London SW12 9BS rTelephone 020-8675 5211 Fax 020-8675 5449) CIBSE Guide Volume A Design Data Volume B In tallatiol1 and quipment Data Volume C Reference Data
CommlssioniJIg Codes These Codes eover the preliminary checkS eUing to work and regulation of vanous catcgories 0 plan The Codes give a guide to design implications Series A Air Distnbution Systems Series B Boiler Plant
ri s C Automatic Conlrol ystems Cr1es R Refrigerating Sy terns
Sene iN Water Distribution Systems
Technkal Memonllda TM 4 Design Notes for the Middle East TM bull Design otes for Ductwork TM 13 Minimi iog lhc Risk of egiounaires Disease
Research Reports RROI95 Ventilation system hygiene - A review of published
infomlatioo on lhe occurrence and ffects of Olltamination Rl~02J95 Air-to-air heal rec v ry RR0395 rnfluen e of HV C on smoke detectors
ATlONAL ENI [ERING SPECIFICATION LfMITED Southgatc hamber 3739 Southgate Street Winchester S023 9EH (Telephone 01962 842058 Fax 01962 R(8982) BUfLDING S RVICES RESEARCH AND [ ORMATION ASSOCIATIO Old Bracknell Lane West Bracknell Berkshire RG 12 4AH (Telephone Brackl1eU (01344) 426511 Fax 01344 487 -7 )
Application Guides AGln4 De tglJing Vana~le Volume middotylans for KOOnl
iir Movement AG1I91 Commissioning of V Sylcms in Buildings 11 6194 Fire Dampers
B) 94 cntiJalion or KitcneTls
AG389 The Commls ionin of Air Systems In Buildmgs AH2192 Commissioning of Bern - A ~ode of Practice TN2417 I Fire Dampec il) Ventilating Ducl
BEATING VENTILATING A AIR CONDITION G MA UFACTURERS ASSOCIATIO (HEVAC) HEVAC Henley Road Medmenham Marlow Buck SU 2ER (Telephone 01491 578674 ox 01491 575024 Emoimiddot infofetacouk)
Publicatjons Air Diffusion Guide Guide to Air Handling Unit Leakage Testing Guide to Good Practice Air Handling Unit Real Room Acoustic ~ st Procedure Specification for the ertiiicatioll ofAir Filters Method of Test for Water Rejection PerfOnTlatce of Louvrcs Subjected 1(1
Simulated Rainfall Test Procedure for Acoustic Loo cs Specification 10 Floor GrilJes - Types Performan e and Method ofTest Specification for the Determination of the Collection Efficiency of SilJ1d
Trap Louvre Domestic Mechwlical Vclltllalion Systems with Heal Recovery Fan Application Guid
~an and Ouctwork Installation Guide Guide to Fan Noise and Vibration
pecification of Requirements for JallJral Smoke and Heal Exhausl Ventilators
pecification for Powered Smoke and Heat Exhaust Ventilators
Specification of Requirements for Smoke Curtains Design Gujue of Smoke Ventilation for Single Storey Lodustrilll Building~
Including those with Mezzanine Floor and IIi Racked Storage Warehou es - Issue 3
Guidance for the Design of Smoke entilation YSlem for Covered and Undergrollnd Car Parks - lssue 1
Application of SOloke Control Equipment and Syst m Guid to Good Practice - Isue J
58
DW154 Sp(C~tiifitiol for Plastics Ductwork
BRITISH STANDARDS INSTIT TION Sales Department 101 P ntooviLle Road London NI 9ND (felephone 020-78 1 78801)
CP 413 1973 Ducts for building ervices
SS 476 Fire tes on building matenals and lruc(ure
Part 4 19 4 Non-combustibility lest or materials
Part 6 I Fire propagation lest for materials
Part 7 1993 Surface spread of tlarnJ tesls for materia
Part 20 1987 Fir resistance of elements of construction
Part 21 1987 Fire r sistlUlce of loadbeanng elements of construction
Part 22 1987 Fhe istallceofllon-loadbearing elemcllts ofconsttuclion Part 23 1987 Contribution of componcnts to the fire resistance 0 a
structure
Part 24t987 Fire resi lance of wl1lilation ductl
SS 5588 nan 919 0 Fire Precautions III thc desIgn and OOSlnJ lion of buildings
S 729 1971 Hot dip galvanized oatiugs (or irOIl aod stcel articles
BS 1449 Steel plate sheet and Irip
Pan 11991 Carbon steel plate heel and strip Part 2 1983 Stainless steel plate sheer and strip
and
B middotENJOI49-2 996 BSEN 10149- 1991)
BSEN 10131 1992
BSEN22063 Sprayed metal coarings 1994 Protection of iron and steel by aluminium and zinc against
atmospheric cOlosion Irotectiotl of iron and ste I against corro ion and oxishydation at elevared temperatures
BS 353 1981 Glossary of lerms relnting to thermal insulation
BS ISO 1479 Self-tapplngscrewsandmetallicdri c crew
B -lSO 7049
1994
B 4800 1989 Painl colour for building purposes B 4848 l0 rolled structural steel sections
Part4 1972 Equal and unequal angles BS 5422 1990 Specification for the use of therm illuating matcriulS
SS 5720 1979 ode of practice for mechanical veutilating and air C 11shy
dirionin bull in building
l3S PR 12814-1 Bend resting for plasric welds
SS PR 12814-2 Tensile testing for plastic welds
SS PR 13067 Appro altesting for plastic welds
BS PR EN I 100-] Vi ual in pection ofplaslic welds
SHEET METAL AND AIR CONDITIONING CONTR-CTORS NATIONAL ASSOCIATION INC (SMACNA) Headquarters 420 I Lafayeue Center Drive Chanlilly Virginia 2051-1209
Mailing Address pa Box 221230 Cbantilly Virginilt120 153-1230
Telephone (703) 803-2980 Fax (703) 803-3732
Accepted IJJdustry Pl3Gtice for Industrial Duct Constnlelion 197 ) i-rchitecmral Sheet kwl Manual ([993)
Comractors Guide lor Modification 10 ooslruerion Colllraets 1993 Ducted Eleclric Heat Guide for ir Handling Ssrerns (1994)
En~rgy ollservatioD Guidelines (1984) Energy Recovery Equipment yslClllS (199l
Fibrou GIns Duct onS1ntClion Standards (1992)
Fire Smoke amp Radiation Damper In tall Guide for HVA Syst ms (1992) Guide t leel Stack 1(95)
HVA Air Duct Leakage Test Manual (19 ) HVA COlllmissioning lvlanual (1994)
H A Duct Construction Standards-Metal amp Flexible (1995) Addendum 01 (Nov 1997)
HVA Duct Systems Inspection Guide (1989)
HVA ySlems-Application (1986) nVAC ByternS-DLlct D ign (1990)
HVi Systems-Testing Adjusting amp Balancing (1993)
indoor Air Quality Manual (1993) tcheu quipment Fabrication Guidelmes (1990)
Managers Guide for elding (1993)
Rectangular Industrial Duct Cons1TUction Standards (19 0) Round Industrial Duct oustmction Standards (1977)
Sei mic Restraint Manual (1991) (wl Appendix E 1993) SMACNA Ma le Index ()fTechnical Publications (1995) Tbennoplnstic Duct CPY ) Construction Manual 1994)
DEPARTME OF THE ENVIRO MENT (Publications Centre) H Stationery Oflice 5 Nine Elms Lane London SWS 5DR
MampEJ 011972 Electrical in tallat1011 in buildings ( ew Editiou)
IampE 0319 Healing hot and cold wat r steam and gas losla1lations for buildings
M amp - No4 1970 Central heating and hot and cold ~ ateT in tallations for
dwelling
M amp ENo100 1971 Mechanical ventilation for building~
ASSOCIATION FOR SPECIALIST FIRE PROTECTlO As ociation House 235 Ash Road AJdershot Hampshire GUl2 4DD
Telephone OJ25221322 Fax 0 J252 333901
lublicalioos Fire Ratcd and moke Outlet Ducrwork An Industry Guide t Design and InSlalla lioll
HEALTH AND SAFETY EXEC TIVE Rose Court 2 Southwark Bridge London SEl 9HS Telephone 020-7717 6000
TWJ THE WELD G TlTUTE Abington Hall Abington Cambridge CB16AL Telepbone 0 J223 89162
Publication DatJ Oil w~ldll1g of lhermopla lics
59
DW154 wciiwlioll for Plastics Ductwork
A -=--DIX
Factors
Specific gravity shy pp = 091 approx UPVC = 14 approx
Some miscellaneous conversion factors
To convert
Length Inches to millimetres Feet to metres
Multiply by
2540 03048
To convert
Millimetres to inches Metres to feet
vIultiply by
003937 3281
Area Square inches to square millimetres 6452 Square millimetres to square inches 000155 Square feet to square metres 00929 Square metres to square feet 10764
Volume Cubic feet to cubic metres Cubic feet to litres Gallons (UK) to litres
002832 2831 4546
Cubic metres to cubic feet Litres to cubic feet Litres to gallons (UK)
35315 00353
022
Mass Ounces to grams Pounds to kiJograms Tons to tonnes
2835 04536
1016
Grams to ounces Kilograms to pounds Tonnes to tons
003527 2205
09842
Volume flow Cubic feet per minute to cubic Cubic metres per second to cubic
metres per second 0000472 feet per minute 2119 Cubic feet per mIDute to litres Litres per second to cubic feet
per second 04719 per minute 2119
Motion Feet per minute to metres per second 000508 Metres per second to feet per minute 197
Pressure Inches water gauge to millibars 2491 Inches wateJ- gauge to pascals (Pa) 2491 I Pa = I ewton per square metre = 10-2 millibars
60
Heating and Ventilating Contractors Association Esca House 34 Palace Court London W2 4JG
Tel 020 7313 4900
e-mail contact Itvcaorguk web site wwwhvcaorguk
Fax 020 7727 9268
DW154 Specification for Plastics Ductwork
TABLE 12 - STANDAR ABBREVIATION CONTINUED
ABBREVIATION
IU
L
tv1D
MS
NRD NTS
OBO
OE
PHD
PD
PP
PP
PRD
PVC
RFC
RSC
R
SBO
SO
S1 TST
SSL
TA
TB
TO TJ
TP
TV
TV
OS
UPVC
S
V
VAV
50 RSA
FULL
Induction Unit
Low Level
Motor controlled Damper
Mjld Steel
on Return Damper
at to cale
Opposed Blade Damper
Open End
Parallel Blade Damper
Pneumatic controlled Damper
Polypropylene
Self xtinguishing Polypropylene
Pressure Relief Damper
Polyvinyl Chloride
Rolled Form Chamlel
Rolled Steel Channel
R fUnit
Singl Blade Damper
Smoke Damper
Slip Joint
Stainl t el
tructural Slab Level
To Ab vc
To Blow
Top Down (In Direction of Flow)
Telescopic Joint
Test Point
TU111iog Vane
Top Up (In Direction of Flo )
Voles Otherwise Stated
Unpl3sticisecl Polyvinyl Chloride
Underside
Ultra Violet Light
Variable Air Volume
Rolled Steel Angle (Vith Size)
48
DW154 SJeriiflllioll for Plastics Ductwork
A2 DUCT PRESSUREAPPE DXA Ductwork con truct d to DWIl54 will bebullbullbullbullbullbullbullbullbullbullbullbullbullbull
Air Leakage From Ductwork To be read in conjunction with DW143 A practical guide to Ductwork Leakage Testing
CAUTION As highlighted ill both this docul1lenr and DW14 I lot ellough emphasis can be placed 01 the fact that except for high pressure class C the much more stringent ductwork constructional standard brolght about b the general acceptance of DW154 have irtlally negated the requirement for leakage-testing It is essential lO realise lhat except where it is mandatory this doclllllelll is nOl an endors ~lIlent of the rourine testing of ducts bllt purely a guide to outline the procedures for cononnity with the air leakage limits ill Table l Where the specified methods of assembly and
A3sealing of dlcls are u ed a vi ual inspection wil ordinarily sl~fll e for ver(iatioll of a well engineered and a ceptahfy airtight COl1strucrioll WHERE NOT MANDATORY DUCT LEAKAGE TESTING IS GENERALLY AN UNJUSTIFIED AND SUBSTANTIAL EXPENSE
A1 INTRODUCTION L akage from ducted air distribution systems is an Lmportant consideration in the design and operation of ventilatjon and air conditioning middotystems A ductviork t)ystem tbat ba limited air leakag within defiucd limits wiH cnsUft
that tile design characteristics of the sytem can be maintained It wilJ also ensure that energy and operatLonal cosb are maintained at optimum levels DucLwork constlucted and Ulstalled in accordance with DW154 should minimise a level of air leakage that it) appropriate to tll operating static air pre sur in tile system
A4However it is recouuised that tbe environment in wtJich middotystems are installed is not always conducive to achieving a predictable level of quality in term of system ajr leakage and it is therefore accepted that designer may sometimes require tlle ystem to be tested in part or in total It should be ecogni ed that the testing of duct systems add a ignificant cost to the installation and incur some extra tjm within the programme (Se 47 and 64 re mandatory te-sting)
manufactured to a structural standard that is compatible with the system operating pressure There are three classes of duct con truction to eorre pond with the three pre ure clas meations Class A Lo pressure ducts suita le for a maximum positive operating pressure of 500 Pascal and a maximum negative pressure of -500 Pascals Class B IVledium pressure ductmiddot suitable for a rnaxilnuJJl positive operafjn o pressure of 1000 Pascals and a maxllnum negative pre sure of -750 Pa cal Class C High pre sure ducts suitable for a maximum po ilive operating pressur of 2000 Pa cals and a maximum negativ pres ur of -750 Paltcals
LEAKAGE FROM DUCTWORK Leakao-e front pia tic air ducts occur at the joint~ and is therefore proportional to the total surface area orthe du twork in th system Tb level of leakage i imilarly related to tIle air pres ure in th du t system and whilst there LS n precis formula for calculating the level of air los it i generally accepted that leakage will increase in proportjon to pressure to rbe pOvver of 065 The effect of air leakage from high pressure velocit ductwork is critical tn terms of system perfomlan dege energy consumption and the risk of high frequency noise as ociated with leakage These problems are le critical with medium pressure 10 ity systems but should be con idered Low pres mevelocity ducts present the lowe~t
ri k in tenn of tbe effect of leakage on the operation of the s stern
SYSTEM LEAKAGE LOSS As there i no di ct relatLonship between th volume of air conv yed and the surface area f the ductwork sy tern required to match the building configuratmn it is difficult to express air leakage a a percentage of total air volume Similarly the operating pressure will vary throughollt lh 3 system and a leakage is related to pre me the calculations ar comple However it is generally ac epted tbat in typical good quaJjty systems the leakage from
49
DW154 Specificatioll for Plastics Ductwork
each class of duct llnd r operating condition will be io the region of CIa S A low pressure 6 Clas B medium pres un 3 Clas C high pressure 2
A5 SPECIFYING AIR LEAKAGE TESTING Re peeting both the co -t and programme implications a sociated with te ling du 1 for leakage the designer may for example indicate that a particular system is te ted as follow
a) High pressure ducts - all tested b) Medium pr ssure duets - 10 of the
ductwork shall be s eet d at random and tested
c) Low pre sure - unte ed In any case where a random te t i elected for medium pre sure ductmiddot the followin c1au~e is suggested for inclusion by the de ign r
The designer hall elect at random a maxirnwlI of 10 of the dUCl system to bt tested for air leakage The duct hall be tested af the pressure recommended in Table J3 for the assifi atiol for the ectiol1 of the ductwork that is to be tested The tests shall be carried Ollt as the work proceeds and prior to the application of thermal insulation In the event of test failure of the randomlY selected section the designer shall have The right to select two La1her e tiolls at random for resting Where succes ive failures are identified there shall be a Tight to require rhl COl11raCWr 10 apply remedial attention to the complete ductwork system Th contractor shall provide documented eviden e of the calculalions used to arrive (1
the allowable 10 I for the section to be tested and the client or his agent shall willess and sign the results of the test
able 13 Air leakage rates
Maximum leakage of duct work Static
prcssUft Low-pressure edium-prc-sure I Iigh-prebull me diJfercntial Class A Class B Class C
1 2 J 4 Pa Litres per second per quare metre of surface area 100 054 018 ZOO 084 028 300 110 037 400 132 044 500 153 051 600 058 019 700 064 021 800 069 023 900 075 025
1000 080 027 1100 1200 1300 1400 1500
029 030 032 033 035
1600 1700 1800 1900 2000
036 038 039 040 042
Note Recommend d mean test presures are highlighted iD bold type with the actual selection being left to tll test operator
50
DW154 Sfeeiieaioll for Plastics Ductwork
A9
A10
and air leakage classification for the y em under test
DESIGNERS CALCULATIONS The designer can middotaJculate with reasonable accuracy the predicted total loss from a ystem by
a) Calculating the operatin presure in each ection of the sy tern
b) Calculating the surface area of the ductwork in each correspondin pre lire s ction
c) Calulating the allowabl~ los at the operating pressure for each ection of the system (see table 13 for allowable leakage figures)
VARIABLE PRESSUR S IN SYSTEMS De igner can achieve significant co t saving by matchina operating pressures throughout the system to constmctional standard and appropriate air leakage testing eO the practice of specifying construction tandards for whole duct sy tems based on fan discharge pre sure may incur unnece sary costs on a project For example ome large sy terns ould well be classiC ed for I akage limits as follows
Plant room risers CJas C Main floor distriblltJou CIa B Low pre sure outlets Cla A
A6 SPECIAL CASES There may be ~itLlations on a project where circumstance dictate thal pecial consideration be given to containing air loss s eg a long mn of duclwork may incur a di -proportjonate level of air 10 s In ca es such as thi example the designer can specify an improved tandard of airtighmess ie 80 of alJo~able 10 s for la B Ju ts The designer sbould not specif a CIa C t sI at CIa s C pressure for a CIa s B ducl
A7 SUGG S ED RANGE OF TES ING
A8 TESTING OF PLANT ITEMS Items of inline pJant (eg Fig 106 to 115) will not normaUy be included in an air I akage test The dllctwork contractor may indud such itelllS in tbe te t jf rh quipm ot has a certificate of COnfOlnlity for Ihe pres ure clas
bull High pressure duct bull Medium pre sure ducts bull Low pre sur ducts bull Exposed extract syst ID bull Ceiling void extract
systems bull Secondary ducts from
VAV or fan coil units bull Flexjble duct bull Final connections and
branches to grille and diffusers
100 test See A5 Untested UDt sted
Untested
Untested Untested
Untested
SI
i
DW154 SJecijicafion for Plastics Ductwork
ig 116 Permitted leakage at various pressures
Leakage in litres per second per square metre duct surface area
Vgt
o ltgt 0 ltgt N
ltgt Cgt
0 0 cc
0 0
~
g =
g ~
c 0
J
ltgt 0 I
~ ] tn
ltgt ltgt
In ol
~ 0 ~ 8 ~
~
c ltgt ltgt
~ CJ
~ ~ ~ ~ 8
0shyij
~ ~ ~ t
ltgt ltgt 00
l
~
~ Q
c C
~ rshy
e ltgt
I 1
I Cgt ltgtv
c Co ~
~~ ~ 10
I
0 Cgt
fJshyq 410 ) 1 ltgt
ltgt N
~ shy ltgt ltgt
~ I 1
c
52
DW154 Specificatio for Plastics Ductwork
Example of a completed test sheet Test No
General
Name of job N~ jC43Pt(r2lef Building Repound ~(~~0
Part 1 - Physical details
a Section of duct work to be tested ~(diffPIfff~el1f3rd Floor
b Drawing Number g91~~ c ssure aSSJ L atlOn V~Jl~IRfYgtg~~lPre Cl T Class C
d Test static pressure -(9 raErq~ ~~~~-~~J~~~ ~~ ~~~~ll
Leakaoe factor 9~-tre3$ecMz I OM REFTOTABLE 13)e b bullbullbullbullbullbullbull
f Surface area of duct under test Q~tJJItetre$ CPROMCALCU TIO BELOW)bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull ampampamp bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull
g ]Vlaxi mum permitted leakage -~ (~i~~0 ~~r~~ ~~~l-~-11~ ~~~Q
Part 2 - Test particulars
a Duct static pressure reading 9QFt~q~ ~ middot~~~1 ~~
b Manufacturer and type of liow measuring d vice (-~~~cJ~Y-9Q7EYg c Range of measurement of now measuring device QtP)OQ~(e~~~0I~~~~1~I~ ~~~~~~W~
d Reading of flm measurin o device pmiddot IFROM RIO)ftscag ~
I (DERlVED [ROM CHART SUPPUED WITH RIG US 0 ud)1e Interpreted air flow leakage rate ~(~~~f~~~ (~l~~~~~~~~~~~~~~~~~I
f Duration ~~~~~norn~allY l~ lnil1Ut~~d~~~ it1~ W~ Date of test ~(lITled ut by Wltll s ed by ~ ~
(~lJ MIJLrr) (Si~rrfltJUYJ
Printed Name 1~g0f~ Printed Name ~~Y~9~ and Company 7jl~~~~~( UJd CompanY AB COII$Itallt8
Width and depth or diameter
Periphery ength Area
millimetreS millimetres metre qL1are metre
800 x 750 3100 1755 5440
600 x 650 2500 557 1193
300 x 300 1200 120 144
305 din 958 700 670
250 dia 785 450 353
TOTAL 8000
53
DW154 Specijilarion for Plastics Ductwork
pA XB
Guida ce No es For he ransport Handling and
Storage of uctwork
avoid damage to adjacent duct panels In somc ca es particularly on con acts calling f r repetitive sizes the use of timber jigs and spacers may be justified Where reduced bulk and greater protection are major factor such as consignments for export transporting ductwork in L shape sections may justify the increa ed ite as embly co ts
It is recommended that before a contract is finalised that consideration is given to the subject of site acces material handling and storage as tbcy havgt a strong influence on the cost efficiency of the overall activity of ductwOlk installation
B3 Handling To minilnise th risk of damage duct sections should be clearly identified and deliveries to site should be closely linked to the installation programme so as to avoid accumulation of
B1 Storage and Handling of Ra Material Material should be stored in suitably designed racking out of direct unJight Where possible the e racks should be metal to earth Edges of cut she t may be harp and protective gloves are advised Wearing teel toe-capped boots is recommended Most pIa tic sheet is manufactured with smootb mfaces andor is suppLied with protective coating Care must be taken to prevent accidental lippag of stacked materials Beiuoshy good electrical insulators the movement of stock unless earthed will allow the build up of stati All stock shapes are chemically stable at normal temperature Whil t some raw materials used in their manufacture may themselves pre ent a toxic hazard once incorporated into the lOck bape they no long r constitute such a hazard and no dermatitic bazard are known nor are any
unfiJied ductwork and minimise double handling It is important to recognise that ductwork panels joint and corners arc susceptible to damage and care must be taken wheu band ling such material through a site During handling individual item of duct work may be liable to light cross sectional deformation until thev become an integral pan of a completed ductwork system Whilst this may temporarily detract from its intended appearance thi deformation will not have any detrimental effect on the functionality of the finally a semblecl system Installation of duct work and asociated plant items ill illevitably involve manual handUng The responsibi Iiry of employers and employees to a ses the risk of personal injury during mallual handling operations is et out in the HS E publication L23 Guidance on Manual Handling Regulations 1992
environmental problems expected 84 Site storage
B2 fransport Large capacity vehicles with high-sided open or closed-top bodies are tlle mo t suitable for the transport of dllctwork Careful consideration should be given to the
Adequate floor space IDust be provided within tbe building for the site storage of ductvork Such storage shalt make due allowance for thc stOf(ne of ductwork in stacks such that access ~ egt
between them is of sufficient width to pennil the removal of item without interference to
unloading of transport on sit a not all siJes b n fit from the material handlino- and access facilities that exi [ in a manufacturing workshop such as crane- fork-lifts or loading bay Site handJiog facilities along with
adjoining sta ks Ductvork components should be positioned so a to avoid crushing Ductwork of small panel size may be stored horizontally however care should be exercised to ensure that tack sizes are limited 10 within
ehicular acce s restrictions may itilluence the type and ize of transport to be uWised
engtlls of ductwork should be positioned 0
the tmctural strength of the duct sections to prevent distortion of the lower sections within the stack
as to avoid crushing Lengths Witll projections such as branches and bends i1anges girths damper quadrauL should be loaded so as to
54
DW154 S1tciic(ltioll for Plastics Ductwork
85 Internal cleanliness of new ductwork The site storage of ductwork introduces the important cODsideration of maintaining the internal cleanliness of the ductwork R feren e should be made to HVCA documentshybull DWffM2 Guide to Good Practice - internal
Cleanliness of New Ductwork Installations If the above conditioDs can not be satisfied consideration should be given by tJle designer to amending the specification to include for Po t Installation Cleaning as covered by tJ1C HVCA documentshybull TRJ17 Guide to Good Practic - Cleanliness
of Ventilation Systems
APPE DIXC
Fi e Retardant inishes C1 Improvement in the fire retardancy of plastic
ducts can be achieved to varying degrees and is wholly dependent llPOll the surface coating laminating resin selected and construction specification adopted In some instances smoke emission is coILSidered equaUy with other speci fication requirernen ts of the materials resistance to ignition and bumjng It is therefore important for design rs to establ ish the clients and officers detailed requirements and not rely on a tbird party interpretation of fire resisting or fire retardant Where possible the specification should refer dir etly to compliance with a British or European Standard identifying the specific sections applicable There are various types of resin and mat rcLnforcements that can achieve a Class 1 surface spread of flame ratin o when tested according to BS476 Part 7 (1987) This test puts materials illto Class I - 4 in descending order of perfoDllance according to the rat and extent of flame spread over their surfac under standard beating conditions Materials should also be tested for flre propagarion to BS476 Part 6 (1989) Tbi tesr measures the amount and rate of heat evolved by the material when subjected to standard heating
conditions Test results are given as an index of Perfonnance (i) whicb is based on three sub indices (iJ (i1) (h) The higher the value of the Index of Performance (i) the greater is the material s contribution to fire growth The higher the value of the sub-index 0) rhe greater the ease of ignition aod flame spread The highest product performance classification as defined in Approved Document B of the Building Regulations is Class O This is acLlieved if a material surface of a composite ploduct i~ either a) composed throughout of materials of
limited combustibility or b) a Class I material which has a tlre
propagation index (i) of not more than 12 and sub-index (i l ) of nor more than 6
01 J Class 0 is not a cla$sif1cation identified in any British Standard test
There are resin system reported to be classified to Class O when tested to BS476 Pcl1S 6 and 7 however designers need to ensure that such sysrems can be applied to their proposed design In propriety resinmat system available the fabrication techniques and COITect application are critical to the integrity of the reinforcing and clas ificatiol1 For example in some systems the u e of a non-fire retardant gelcont on a fire retardant substrate would reduce the classification For further information see HVCA publication DW144 Appendix D
55
DW154 SplCijiClIliol1 for Plastics Ductwork
x Guidance otes For nspectmiddoton Servicing a d
Clean-ng Access Openings
D1 GE ERAL This appendix highlight in ummary fOI111
the acce considerations that hould be made by the design r iD terms of inspection servicing and cleaning Having considered the seop and the design of the dUCI work system relative to the guidelines outlined below the designer should clearly indicate which levels of acces should be incorporated into the manufacture of a new duct work system (See Table 14 and Note I b low it
D2 DESIGN CONSIDERATIONS
D21 In ptction and servicing requireshyments are set out in Section 15 of Lhis specification
D22 Cleaning requirements are set out in the HVCA pubUcation TRl7 Guide to Good Practice Clean Lines of Ventilation Systems and the guide tates The precise location ize and
type of access would be dependent on the type of ductwork cleaning inspection and te ting metbods to b adopted Care protection and standards of cleanliness prior LO cOlllmisionin o
are set out in th AV A publication DWITM2 Guide to Good Practice Internal Cleanliness of New Ductwork Installations and th guide state Wh re specific limits of cleanliness are required ductwork sball be cleaned after installation by a spcialist cleaning contractor It will b in the interests of tht desioner botb financially and practically to cunsider employing a specialist c1eauing contractor at tbe
outset of a contract to internally clean newly installed ductwork prior to bandover This approach would reali e the following benefit shyi) Tb actual numb r of cleaning
access panels could be detennined to suit the method of cleaning to be adopted (This may be 1 s than the maximum requiremen listed under Lev 13 of Table 14)
ii) Clear directions could b given to the ductwork contractor as to tJle size and location of cleaning access panels that are required to be fitted during the mauushyfaclunng pro s
iii) The specialist cleaning operation prior to commi ioning vould enable the cleaning contractor to verify the practical acee requirement for the future cleaning operation associated -vitb a regular maintenance programme
iv) A specialist cleaning operation prior to commissioning would allow the designer to omit from the speeilicatiolJ the DWrrM2 requirem nt for factory sealing protection wipe downs and capping-off
v) Specialist Ieall ill 0 to the measurable standard defin d in TR17 will allow an objective definition of cleanline to be achieved
Car ful consideration must be gIven by the designer to the practl aJ problems associated witb the manufacture and fitting of suitably si Led access panel on small cross section duct and on the circular faces of rouod and flat oval ducts in particular
D23 Special con ideration must be given by the de igner to the practical problems associated with gaining personnel access to heavily congested ceiling areas and multi-la red du twork systems This approach would avoid
56
DW154 Spfciication for Plastics Ductwork
the possibility of access panels being D3 ACCESS 0 IN-LINE EQUIPMENT incorporated into a ductwork system at the This appendix unly covers acc il1spection manufacturing stage that were later found in through the ductwork body adjacent to an item practice to be inaccessible for either ervicing of in-line equipment and not openings in the or cleaning activities equipment itself
able 14 Acce requirements for inspection servicing and cleaning
HVCA PUBLICATIO REFE NeE (uidtgt 10 Gund Prartict
Adjace t OW144 Cleanliness orVcnlillltio S~lcr~ fRjJ7
in-line LeyeJ 1 Level 2 Level 3 ite sequipment pcdionSen lcin~ Section d C1eaniJl( SUn(O)lnspc lion Palle ltk~m_n
2011 (minimum OiL Jubje-ct to duct ~zel (ft~ -Panels
Control Da pcrs One (inspection) 203 One 300 mm x 200 mm Both sid Fire Dampers One (sCTjdJl~) 20211 One 300 0101 x 200 mm One side HeatingCooling Coils One (inspedion) 20213 One 300 mm x 200 mm (lIpstream) Both sides Attenuators (rectangular) None required One 300 mm x 200 mm (downstream) Both sides Attenuators (circular) one retluired One 300 mm x 200 mm (downstream) One side Filter Sections One (inspection) 20212 one required Uoth sides Air Turn Vanes None requjred None required Both sides Changes of Direction None required one required One side In-Duct FansDevices One (inspection) 20213 None required Both sides l
1 In the absence of any indication by the designer only Level ) access will be jncorporated into a new ductwork system
2 Tbe panel izes associated with Lev lis I and 3 acee s ar e middottablished by reference to Section 20 of DW144 and Section 2 ofTRll7 respectively
57
DW154 Speclfifatio for Plastics Ductwork
pA XE
B-bliography Included in this Bibliography are technical pUblications which may be of interest (0 ductwork designers fabricators and erectors and to tho e in the heating ventilatlng air conditioning industries generally nquiric should be made of the relevant organisation at the address quoted Since its publication other addresse contained within 0V154 mav have changed and some pubJicalions may have been superseded
HEATING AND VENTILATING CONTRACTORS ASSOCIATION
4 Palace Court London W2 4JG Telephone 020-7229 2488 Fax 020-7727 9268
Orders fo FlY A Publications Old Matlsion House Eamont Bridge Penrith Cumbria CA 10 2BX (Telephone 01768 864771 Fax 01768 86718) Email hvcapoblicationshvwelfarecouk DWn 44 pe ilicatiun for sheet mctal duclwork (Iow- mediulllshy
and high-pressure) 1998) DWIl4 A practical guide to dUGI ork I akage te ting
(revised 2000) DWII54 Specification for plastic~ duct rk DW171 Guide to good Practice for kitchen venlibtion system DW191 Guide to good pracuce glass fibre ductwoJk DwrrMI Acceptance cheme for new products - Redangolar cro
joint classification Guide to good pra tice - Internal cleanliness of new ductwork installations Guide to good practice for the design for the Installation of lire and smoke uampers
J 1Other puhlications
HampV safely guide 5th edition JS2 Tool box talks JS5 Weldlng Safety booklet JSI9 afety facts bo klet Fact sheets 1-24 2nd edition JS2J COSHH manual volume 1 Advice on compliance with the
regulations 1521A CO I-rH manual volume 2 Asses mcnt h ets JS23 Ri k management manual TR3 BrazinltT and bronze welding of copper pipework cUld sheet
(I 976) TR5 Welding of carbon steel pipework (1980)
TR6 Guide to Good Practice for Site Pre sure Testing of Pipework (19 0) Guide to good practice cleanliness of ventilation Ylem
CHARTERED IN TITUTlO OF BUILDING SERVICES E G EERS Delta House 222 Balham High Road London SW12 9BS rTelephone 020-8675 5211 Fax 020-8675 5449) CIBSE Guide Volume A Design Data Volume B In tallatiol1 and quipment Data Volume C Reference Data
CommlssioniJIg Codes These Codes eover the preliminary checkS eUing to work and regulation of vanous catcgories 0 plan The Codes give a guide to design implications Series A Air Distnbution Systems Series B Boiler Plant
ri s C Automatic Conlrol ystems Cr1es R Refrigerating Sy terns
Sene iN Water Distribution Systems
Technkal Memonllda TM 4 Design Notes for the Middle East TM bull Design otes for Ductwork TM 13 Minimi iog lhc Risk of egiounaires Disease
Research Reports RROI95 Ventilation system hygiene - A review of published
infomlatioo on lhe occurrence and ffects of Olltamination Rl~02J95 Air-to-air heal rec v ry RR0395 rnfluen e of HV C on smoke detectors
ATlONAL ENI [ERING SPECIFICATION LfMITED Southgatc hamber 3739 Southgate Street Winchester S023 9EH (Telephone 01962 842058 Fax 01962 R(8982) BUfLDING S RVICES RESEARCH AND [ ORMATION ASSOCIATIO Old Bracknell Lane West Bracknell Berkshire RG 12 4AH (Telephone Brackl1eU (01344) 426511 Fax 01344 487 -7 )
Application Guides AGln4 De tglJing Vana~le Volume middotylans for KOOnl
iir Movement AG1I91 Commissioning of V Sylcms in Buildings 11 6194 Fire Dampers
B) 94 cntiJalion or KitcneTls
AG389 The Commls ionin of Air Systems In Buildmgs AH2192 Commissioning of Bern - A ~ode of Practice TN2417 I Fire Dampec il) Ventilating Ducl
BEATING VENTILATING A AIR CONDITION G MA UFACTURERS ASSOCIATIO (HEVAC) HEVAC Henley Road Medmenham Marlow Buck SU 2ER (Telephone 01491 578674 ox 01491 575024 Emoimiddot infofetacouk)
Publicatjons Air Diffusion Guide Guide to Air Handling Unit Leakage Testing Guide to Good Practice Air Handling Unit Real Room Acoustic ~ st Procedure Specification for the ertiiicatioll ofAir Filters Method of Test for Water Rejection PerfOnTlatce of Louvrcs Subjected 1(1
Simulated Rainfall Test Procedure for Acoustic Loo cs Specification 10 Floor GrilJes - Types Performan e and Method ofTest Specification for the Determination of the Collection Efficiency of SilJ1d
Trap Louvre Domestic Mechwlical Vclltllalion Systems with Heal Recovery Fan Application Guid
~an and Ouctwork Installation Guide Guide to Fan Noise and Vibration
pecification of Requirements for JallJral Smoke and Heal Exhausl Ventilators
pecification for Powered Smoke and Heat Exhaust Ventilators
Specification of Requirements for Smoke Curtains Design Gujue of Smoke Ventilation for Single Storey Lodustrilll Building~
Including those with Mezzanine Floor and IIi Racked Storage Warehou es - Issue 3
Guidance for the Design of Smoke entilation YSlem for Covered and Undergrollnd Car Parks - lssue 1
Application of SOloke Control Equipment and Syst m Guid to Good Practice - Isue J
58
DW154 Sp(C~tiifitiol for Plastics Ductwork
BRITISH STANDARDS INSTIT TION Sales Department 101 P ntooviLle Road London NI 9ND (felephone 020-78 1 78801)
CP 413 1973 Ducts for building ervices
SS 476 Fire tes on building matenals and lruc(ure
Part 4 19 4 Non-combustibility lest or materials
Part 6 I Fire propagation lest for materials
Part 7 1993 Surface spread of tlarnJ tesls for materia
Part 20 1987 Fir resistance of elements of construction
Part 21 1987 Fire r sistlUlce of loadbeanng elements of construction
Part 22 1987 Fhe istallceofllon-loadbearing elemcllts ofconsttuclion Part 23 1987 Contribution of componcnts to the fire resistance 0 a
structure
Part 24t987 Fire resi lance of wl1lilation ductl
SS 5588 nan 919 0 Fire Precautions III thc desIgn and OOSlnJ lion of buildings
S 729 1971 Hot dip galvanized oatiugs (or irOIl aod stcel articles
BS 1449 Steel plate sheet and Irip
Pan 11991 Carbon steel plate heel and strip Part 2 1983 Stainless steel plate sheer and strip
and
B middotENJOI49-2 996 BSEN 10149- 1991)
BSEN 10131 1992
BSEN22063 Sprayed metal coarings 1994 Protection of iron and steel by aluminium and zinc against
atmospheric cOlosion Irotectiotl of iron and ste I against corro ion and oxishydation at elevared temperatures
BS 353 1981 Glossary of lerms relnting to thermal insulation
BS ISO 1479 Self-tapplngscrewsandmetallicdri c crew
B -lSO 7049
1994
B 4800 1989 Painl colour for building purposes B 4848 l0 rolled structural steel sections
Part4 1972 Equal and unequal angles BS 5422 1990 Specification for the use of therm illuating matcriulS
SS 5720 1979 ode of practice for mechanical veutilating and air C 11shy
dirionin bull in building
l3S PR 12814-1 Bend resting for plasric welds
SS PR 12814-2 Tensile testing for plastic welds
SS PR 13067 Appro altesting for plastic welds
BS PR EN I 100-] Vi ual in pection ofplaslic welds
SHEET METAL AND AIR CONDITIONING CONTR-CTORS NATIONAL ASSOCIATION INC (SMACNA) Headquarters 420 I Lafayeue Center Drive Chanlilly Virginia 2051-1209
Mailing Address pa Box 221230 Cbantilly Virginilt120 153-1230
Telephone (703) 803-2980 Fax (703) 803-3732
Accepted IJJdustry Pl3Gtice for Industrial Duct Constnlelion 197 ) i-rchitecmral Sheet kwl Manual ([993)
Comractors Guide lor Modification 10 ooslruerion Colllraets 1993 Ducted Eleclric Heat Guide for ir Handling Ssrerns (1994)
En~rgy ollservatioD Guidelines (1984) Energy Recovery Equipment yslClllS (199l
Fibrou GIns Duct onS1ntClion Standards (1992)
Fire Smoke amp Radiation Damper In tall Guide for HVA Syst ms (1992) Guide t leel Stack 1(95)
HVA Air Duct Leakage Test Manual (19 ) HVA COlllmissioning lvlanual (1994)
H A Duct Construction Standards-Metal amp Flexible (1995) Addendum 01 (Nov 1997)
HVA Duct Systems Inspection Guide (1989)
HVA ySlems-Application (1986) nVAC ByternS-DLlct D ign (1990)
HVi Systems-Testing Adjusting amp Balancing (1993)
indoor Air Quality Manual (1993) tcheu quipment Fabrication Guidelmes (1990)
Managers Guide for elding (1993)
Rectangular Industrial Duct Cons1TUction Standards (19 0) Round Industrial Duct oustmction Standards (1977)
Sei mic Restraint Manual (1991) (wl Appendix E 1993) SMACNA Ma le Index ()fTechnical Publications (1995) Tbennoplnstic Duct CPY ) Construction Manual 1994)
DEPARTME OF THE ENVIRO MENT (Publications Centre) H Stationery Oflice 5 Nine Elms Lane London SWS 5DR
MampEJ 011972 Electrical in tallat1011 in buildings ( ew Editiou)
IampE 0319 Healing hot and cold wat r steam and gas losla1lations for buildings
M amp - No4 1970 Central heating and hot and cold ~ ateT in tallations for
dwelling
M amp ENo100 1971 Mechanical ventilation for building~
ASSOCIATION FOR SPECIALIST FIRE PROTECTlO As ociation House 235 Ash Road AJdershot Hampshire GUl2 4DD
Telephone OJ25221322 Fax 0 J252 333901
lublicalioos Fire Ratcd and moke Outlet Ducrwork An Industry Guide t Design and InSlalla lioll
HEALTH AND SAFETY EXEC TIVE Rose Court 2 Southwark Bridge London SEl 9HS Telephone 020-7717 6000
TWJ THE WELD G TlTUTE Abington Hall Abington Cambridge CB16AL Telepbone 0 J223 89162
Publication DatJ Oil w~ldll1g of lhermopla lics
59
DW154 wciiwlioll for Plastics Ductwork
A -=--DIX
Factors
Specific gravity shy pp = 091 approx UPVC = 14 approx
Some miscellaneous conversion factors
To convert
Length Inches to millimetres Feet to metres
Multiply by
2540 03048
To convert
Millimetres to inches Metres to feet
vIultiply by
003937 3281
Area Square inches to square millimetres 6452 Square millimetres to square inches 000155 Square feet to square metres 00929 Square metres to square feet 10764
Volume Cubic feet to cubic metres Cubic feet to litres Gallons (UK) to litres
002832 2831 4546
Cubic metres to cubic feet Litres to cubic feet Litres to gallons (UK)
35315 00353
022
Mass Ounces to grams Pounds to kiJograms Tons to tonnes
2835 04536
1016
Grams to ounces Kilograms to pounds Tonnes to tons
003527 2205
09842
Volume flow Cubic feet per minute to cubic Cubic metres per second to cubic
metres per second 0000472 feet per minute 2119 Cubic feet per mIDute to litres Litres per second to cubic feet
per second 04719 per minute 2119
Motion Feet per minute to metres per second 000508 Metres per second to feet per minute 197
Pressure Inches water gauge to millibars 2491 Inches wateJ- gauge to pascals (Pa) 2491 I Pa = I ewton per square metre = 10-2 millibars
60
Heating and Ventilating Contractors Association Esca House 34 Palace Court London W2 4JG
Tel 020 7313 4900
e-mail contact Itvcaorguk web site wwwhvcaorguk
Fax 020 7727 9268
DW154 SJeriiflllioll for Plastics Ductwork
A2 DUCT PRESSUREAPPE DXA Ductwork con truct d to DWIl54 will bebullbullbullbullbullbullbullbullbullbullbullbullbullbull
Air Leakage From Ductwork To be read in conjunction with DW143 A practical guide to Ductwork Leakage Testing
CAUTION As highlighted ill both this docul1lenr and DW14 I lot ellough emphasis can be placed 01 the fact that except for high pressure class C the much more stringent ductwork constructional standard brolght about b the general acceptance of DW154 have irtlally negated the requirement for leakage-testing It is essential lO realise lhat except where it is mandatory this doclllllelll is nOl an endors ~lIlent of the rourine testing of ducts bllt purely a guide to outline the procedures for cononnity with the air leakage limits ill Table l Where the specified methods of assembly and
A3sealing of dlcls are u ed a vi ual inspection wil ordinarily sl~fll e for ver(iatioll of a well engineered and a ceptahfy airtight COl1strucrioll WHERE NOT MANDATORY DUCT LEAKAGE TESTING IS GENERALLY AN UNJUSTIFIED AND SUBSTANTIAL EXPENSE
A1 INTRODUCTION L akage from ducted air distribution systems is an Lmportant consideration in the design and operation of ventilatjon and air conditioning middotystems A ductviork t)ystem tbat ba limited air leakag within defiucd limits wiH cnsUft
that tile design characteristics of the sytem can be maintained It wilJ also ensure that energy and operatLonal cosb are maintained at optimum levels DucLwork constlucted and Ulstalled in accordance with DW154 should minimise a level of air leakage that it) appropriate to tll operating static air pre sur in tile system
A4However it is recouuised that tbe environment in wtJich middotystems are installed is not always conducive to achieving a predictable level of quality in term of system ajr leakage and it is therefore accepted that designer may sometimes require tlle ystem to be tested in part or in total It should be ecogni ed that the testing of duct systems add a ignificant cost to the installation and incur some extra tjm within the programme (Se 47 and 64 re mandatory te-sting)
manufactured to a structural standard that is compatible with the system operating pressure There are three classes of duct con truction to eorre pond with the three pre ure clas meations Class A Lo pressure ducts suita le for a maximum positive operating pressure of 500 Pascal and a maximum negative pressure of -500 Pascals Class B IVledium pressure ductmiddot suitable for a rnaxilnuJJl positive operafjn o pressure of 1000 Pascals and a maxllnum negative pre sure of -750 Pa cal Class C High pre sure ducts suitable for a maximum po ilive operating pressur of 2000 Pa cals and a maximum negativ pres ur of -750 Paltcals
LEAKAGE FROM DUCTWORK Leakao-e front pia tic air ducts occur at the joint~ and is therefore proportional to the total surface area orthe du twork in th system Tb level of leakage i imilarly related to tIle air pres ure in th du t system and whilst there LS n precis formula for calculating the level of air los it i generally accepted that leakage will increase in proportjon to pressure to rbe pOvver of 065 The effect of air leakage from high pressure velocit ductwork is critical tn terms of system perfomlan dege energy consumption and the risk of high frequency noise as ociated with leakage These problems are le critical with medium pressure 10 ity systems but should be con idered Low pres mevelocity ducts present the lowe~t
ri k in tenn of tbe effect of leakage on the operation of the s stern
SYSTEM LEAKAGE LOSS As there i no di ct relatLonship between th volume of air conv yed and the surface area f the ductwork sy tern required to match the building configuratmn it is difficult to express air leakage a a percentage of total air volume Similarly the operating pressure will vary throughollt lh 3 system and a leakage is related to pre me the calculations ar comple However it is generally ac epted tbat in typical good quaJjty systems the leakage from
49
DW154 Specificatioll for Plastics Ductwork
each class of duct llnd r operating condition will be io the region of CIa S A low pressure 6 Clas B medium pres un 3 Clas C high pressure 2
A5 SPECIFYING AIR LEAKAGE TESTING Re peeting both the co -t and programme implications a sociated with te ling du 1 for leakage the designer may for example indicate that a particular system is te ted as follow
a) High pressure ducts - all tested b) Medium pr ssure duets - 10 of the
ductwork shall be s eet d at random and tested
c) Low pre sure - unte ed In any case where a random te t i elected for medium pre sure ductmiddot the followin c1au~e is suggested for inclusion by the de ign r
The designer hall elect at random a maxirnwlI of 10 of the dUCl system to bt tested for air leakage The duct hall be tested af the pressure recommended in Table J3 for the assifi atiol for the ectiol1 of the ductwork that is to be tested The tests shall be carried Ollt as the work proceeds and prior to the application of thermal insulation In the event of test failure of the randomlY selected section the designer shall have The right to select two La1her e tiolls at random for resting Where succes ive failures are identified there shall be a Tight to require rhl COl11raCWr 10 apply remedial attention to the complete ductwork system Th contractor shall provide documented eviden e of the calculalions used to arrive (1
the allowable 10 I for the section to be tested and the client or his agent shall willess and sign the results of the test
able 13 Air leakage rates
Maximum leakage of duct work Static
prcssUft Low-pressure edium-prc-sure I Iigh-prebull me diJfercntial Class A Class B Class C
1 2 J 4 Pa Litres per second per quare metre of surface area 100 054 018 ZOO 084 028 300 110 037 400 132 044 500 153 051 600 058 019 700 064 021 800 069 023 900 075 025
1000 080 027 1100 1200 1300 1400 1500
029 030 032 033 035
1600 1700 1800 1900 2000
036 038 039 040 042
Note Recommend d mean test presures are highlighted iD bold type with the actual selection being left to tll test operator
50
DW154 Sfeeiieaioll for Plastics Ductwork
A9
A10
and air leakage classification for the y em under test
DESIGNERS CALCULATIONS The designer can middotaJculate with reasonable accuracy the predicted total loss from a ystem by
a) Calculating the operatin presure in each ection of the sy tern
b) Calculating the surface area of the ductwork in each correspondin pre lire s ction
c) Calulating the allowabl~ los at the operating pressure for each ection of the system (see table 13 for allowable leakage figures)
VARIABLE PRESSUR S IN SYSTEMS De igner can achieve significant co t saving by matchina operating pressures throughout the system to constmctional standard and appropriate air leakage testing eO the practice of specifying construction tandards for whole duct sy tems based on fan discharge pre sure may incur unnece sary costs on a project For example ome large sy terns ould well be classiC ed for I akage limits as follows
Plant room risers CJas C Main floor distriblltJou CIa B Low pre sure outlets Cla A
A6 SPECIAL CASES There may be ~itLlations on a project where circumstance dictate thal pecial consideration be given to containing air loss s eg a long mn of duclwork may incur a di -proportjonate level of air 10 s In ca es such as thi example the designer can specify an improved tandard of airtighmess ie 80 of alJo~able 10 s for la B Ju ts The designer sbould not specif a CIa C t sI at CIa s C pressure for a CIa s B ducl
A7 SUGG S ED RANGE OF TES ING
A8 TESTING OF PLANT ITEMS Items of inline pJant (eg Fig 106 to 115) will not normaUy be included in an air I akage test The dllctwork contractor may indud such itelllS in tbe te t jf rh quipm ot has a certificate of COnfOlnlity for Ihe pres ure clas
bull High pressure duct bull Medium pre sure ducts bull Low pre sur ducts bull Exposed extract syst ID bull Ceiling void extract
systems bull Secondary ducts from
VAV or fan coil units bull Flexjble duct bull Final connections and
branches to grille and diffusers
100 test See A5 Untested UDt sted
Untested
Untested Untested
Untested
SI
i
DW154 SJecijicafion for Plastics Ductwork
ig 116 Permitted leakage at various pressures
Leakage in litres per second per square metre duct surface area
Vgt
o ltgt 0 ltgt N
ltgt Cgt
0 0 cc
0 0
~
g =
g ~
c 0
J
ltgt 0 I
~ ] tn
ltgt ltgt
In ol
~ 0 ~ 8 ~
~
c ltgt ltgt
~ CJ
~ ~ ~ ~ 8
0shyij
~ ~ ~ t
ltgt ltgt 00
l
~
~ Q
c C
~ rshy
e ltgt
I 1
I Cgt ltgtv
c Co ~
~~ ~ 10
I
0 Cgt
fJshyq 410 ) 1 ltgt
ltgt N
~ shy ltgt ltgt
~ I 1
c
52
DW154 Specificatio for Plastics Ductwork
Example of a completed test sheet Test No
General
Name of job N~ jC43Pt(r2lef Building Repound ~(~~0
Part 1 - Physical details
a Section of duct work to be tested ~(diffPIfff~el1f3rd Floor
b Drawing Number g91~~ c ssure aSSJ L atlOn V~Jl~IRfYgtg~~lPre Cl T Class C
d Test static pressure -(9 raErq~ ~~~~-~~J~~~ ~~ ~~~~ll
Leakaoe factor 9~-tre3$ecMz I OM REFTOTABLE 13)e b bullbullbullbullbullbullbull
f Surface area of duct under test Q~tJJItetre$ CPROMCALCU TIO BELOW)bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull ampampamp bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull
g ]Vlaxi mum permitted leakage -~ (~i~~0 ~~r~~ ~~~l-~-11~ ~~~Q
Part 2 - Test particulars
a Duct static pressure reading 9QFt~q~ ~ middot~~~1 ~~
b Manufacturer and type of liow measuring d vice (-~~~cJ~Y-9Q7EYg c Range of measurement of now measuring device QtP)OQ~(e~~~0I~~~~1~I~ ~~~~~~W~
d Reading of flm measurin o device pmiddot IFROM RIO)ftscag ~
I (DERlVED [ROM CHART SUPPUED WITH RIG US 0 ud)1e Interpreted air flow leakage rate ~(~~~f~~~ (~l~~~~~~~~~~~~~~~~~I
f Duration ~~~~~norn~allY l~ lnil1Ut~~d~~~ it1~ W~ Date of test ~(lITled ut by Wltll s ed by ~ ~
(~lJ MIJLrr) (Si~rrfltJUYJ
Printed Name 1~g0f~ Printed Name ~~Y~9~ and Company 7jl~~~~~( UJd CompanY AB COII$Itallt8
Width and depth or diameter
Periphery ength Area
millimetreS millimetres metre qL1are metre
800 x 750 3100 1755 5440
600 x 650 2500 557 1193
300 x 300 1200 120 144
305 din 958 700 670
250 dia 785 450 353
TOTAL 8000
53
DW154 Specijilarion for Plastics Ductwork
pA XB
Guida ce No es For he ransport Handling and
Storage of uctwork
avoid damage to adjacent duct panels In somc ca es particularly on con acts calling f r repetitive sizes the use of timber jigs and spacers may be justified Where reduced bulk and greater protection are major factor such as consignments for export transporting ductwork in L shape sections may justify the increa ed ite as embly co ts
It is recommended that before a contract is finalised that consideration is given to the subject of site acces material handling and storage as tbcy havgt a strong influence on the cost efficiency of the overall activity of ductwOlk installation
B3 Handling To minilnise th risk of damage duct sections should be clearly identified and deliveries to site should be closely linked to the installation programme so as to avoid accumulation of
B1 Storage and Handling of Ra Material Material should be stored in suitably designed racking out of direct unJight Where possible the e racks should be metal to earth Edges of cut she t may be harp and protective gloves are advised Wearing teel toe-capped boots is recommended Most pIa tic sheet is manufactured with smootb mfaces andor is suppLied with protective coating Care must be taken to prevent accidental lippag of stacked materials Beiuoshy good electrical insulators the movement of stock unless earthed will allow the build up of stati All stock shapes are chemically stable at normal temperature Whil t some raw materials used in their manufacture may themselves pre ent a toxic hazard once incorporated into the lOck bape they no long r constitute such a hazard and no dermatitic bazard are known nor are any
unfiJied ductwork and minimise double handling It is important to recognise that ductwork panels joint and corners arc susceptible to damage and care must be taken wheu band ling such material through a site During handling individual item of duct work may be liable to light cross sectional deformation until thev become an integral pan of a completed ductwork system Whilst this may temporarily detract from its intended appearance thi deformation will not have any detrimental effect on the functionality of the finally a semblecl system Installation of duct work and asociated plant items ill illevitably involve manual handUng The responsibi Iiry of employers and employees to a ses the risk of personal injury during mallual handling operations is et out in the HS E publication L23 Guidance on Manual Handling Regulations 1992
environmental problems expected 84 Site storage
B2 fransport Large capacity vehicles with high-sided open or closed-top bodies are tlle mo t suitable for the transport of dllctwork Careful consideration should be given to the
Adequate floor space IDust be provided within tbe building for the site storage of ductvork Such storage shalt make due allowance for thc stOf(ne of ductwork in stacks such that access ~ egt
between them is of sufficient width to pennil the removal of item without interference to
unloading of transport on sit a not all siJes b n fit from the material handlino- and access facilities that exi [ in a manufacturing workshop such as crane- fork-lifts or loading bay Site handJiog facilities along with
adjoining sta ks Ductvork components should be positioned so a to avoid crushing Ductwork of small panel size may be stored horizontally however care should be exercised to ensure that tack sizes are limited 10 within
ehicular acce s restrictions may itilluence the type and ize of transport to be uWised
engtlls of ductwork should be positioned 0
the tmctural strength of the duct sections to prevent distortion of the lower sections within the stack
as to avoid crushing Lengths Witll projections such as branches and bends i1anges girths damper quadrauL should be loaded so as to
54
DW154 S1tciic(ltioll for Plastics Ductwork
85 Internal cleanliness of new ductwork The site storage of ductwork introduces the important cODsideration of maintaining the internal cleanliness of the ductwork R feren e should be made to HVCA documentshybull DWffM2 Guide to Good Practice - internal
Cleanliness of New Ductwork Installations If the above conditioDs can not be satisfied consideration should be given by tJle designer to amending the specification to include for Po t Installation Cleaning as covered by tJ1C HVCA documentshybull TRJ17 Guide to Good Practic - Cleanliness
of Ventilation Systems
APPE DIXC
Fi e Retardant inishes C1 Improvement in the fire retardancy of plastic
ducts can be achieved to varying degrees and is wholly dependent llPOll the surface coating laminating resin selected and construction specification adopted In some instances smoke emission is coILSidered equaUy with other speci fication requirernen ts of the materials resistance to ignition and bumjng It is therefore important for design rs to establ ish the clients and officers detailed requirements and not rely on a tbird party interpretation of fire resisting or fire retardant Where possible the specification should refer dir etly to compliance with a British or European Standard identifying the specific sections applicable There are various types of resin and mat rcLnforcements that can achieve a Class 1 surface spread of flame ratin o when tested according to BS476 Part 7 (1987) This test puts materials illto Class I - 4 in descending order of perfoDllance according to the rat and extent of flame spread over their surfac under standard beating conditions Materials should also be tested for flre propagarion to BS476 Part 6 (1989) Tbi tesr measures the amount and rate of heat evolved by the material when subjected to standard heating
conditions Test results are given as an index of Perfonnance (i) whicb is based on three sub indices (iJ (i1) (h) The higher the value of the Index of Performance (i) the greater is the material s contribution to fire growth The higher the value of the sub-index 0) rhe greater the ease of ignition aod flame spread The highest product performance classification as defined in Approved Document B of the Building Regulations is Class O This is acLlieved if a material surface of a composite ploduct i~ either a) composed throughout of materials of
limited combustibility or b) a Class I material which has a tlre
propagation index (i) of not more than 12 and sub-index (i l ) of nor more than 6
01 J Class 0 is not a cla$sif1cation identified in any British Standard test
There are resin system reported to be classified to Class O when tested to BS476 Pcl1S 6 and 7 however designers need to ensure that such sysrems can be applied to their proposed design In propriety resinmat system available the fabrication techniques and COITect application are critical to the integrity of the reinforcing and clas ificatiol1 For example in some systems the u e of a non-fire retardant gelcont on a fire retardant substrate would reduce the classification For further information see HVCA publication DW144 Appendix D
55
DW154 SplCijiClIliol1 for Plastics Ductwork
x Guidance otes For nspectmiddoton Servicing a d
Clean-ng Access Openings
D1 GE ERAL This appendix highlight in ummary fOI111
the acce considerations that hould be made by the design r iD terms of inspection servicing and cleaning Having considered the seop and the design of the dUCI work system relative to the guidelines outlined below the designer should clearly indicate which levels of acces should be incorporated into the manufacture of a new duct work system (See Table 14 and Note I b low it
D2 DESIGN CONSIDERATIONS
D21 In ptction and servicing requireshyments are set out in Section 15 of Lhis specification
D22 Cleaning requirements are set out in the HVCA pubUcation TRl7 Guide to Good Practice Clean Lines of Ventilation Systems and the guide tates The precise location ize and
type of access would be dependent on the type of ductwork cleaning inspection and te ting metbods to b adopted Care protection and standards of cleanliness prior LO cOlllmisionin o
are set out in th AV A publication DWITM2 Guide to Good Practice Internal Cleanliness of New Ductwork Installations and th guide state Wh re specific limits of cleanliness are required ductwork sball be cleaned after installation by a spcialist cleaning contractor It will b in the interests of tht desioner botb financially and practically to cunsider employing a specialist c1eauing contractor at tbe
outset of a contract to internally clean newly installed ductwork prior to bandover This approach would reali e the following benefit shyi) Tb actual numb r of cleaning
access panels could be detennined to suit the method of cleaning to be adopted (This may be 1 s than the maximum requiremen listed under Lev 13 of Table 14)
ii) Clear directions could b given to the ductwork contractor as to tJle size and location of cleaning access panels that are required to be fitted during the mauushyfaclunng pro s
iii) The specialist cleaning operation prior to commi ioning vould enable the cleaning contractor to verify the practical acee requirement for the future cleaning operation associated -vitb a regular maintenance programme
iv) A specialist cleaning operation prior to commissioning would allow the designer to omit from the speeilicatiolJ the DWrrM2 requirem nt for factory sealing protection wipe downs and capping-off
v) Specialist Ieall ill 0 to the measurable standard defin d in TR17 will allow an objective definition of cleanline to be achieved
Car ful consideration must be gIven by the designer to the practl aJ problems associated witb the manufacture and fitting of suitably si Led access panel on small cross section duct and on the circular faces of rouod and flat oval ducts in particular
D23 Special con ideration must be given by the de igner to the practical problems associated with gaining personnel access to heavily congested ceiling areas and multi-la red du twork systems This approach would avoid
56
DW154 Spfciication for Plastics Ductwork
the possibility of access panels being D3 ACCESS 0 IN-LINE EQUIPMENT incorporated into a ductwork system at the This appendix unly covers acc il1spection manufacturing stage that were later found in through the ductwork body adjacent to an item practice to be inaccessible for either ervicing of in-line equipment and not openings in the or cleaning activities equipment itself
able 14 Acce requirements for inspection servicing and cleaning
HVCA PUBLICATIO REFE NeE (uidtgt 10 Gund Prartict
Adjace t OW144 Cleanliness orVcnlillltio S~lcr~ fRjJ7
in-line LeyeJ 1 Level 2 Level 3 ite sequipment pcdionSen lcin~ Section d C1eaniJl( SUn(O)lnspc lion Palle ltk~m_n
2011 (minimum OiL Jubje-ct to duct ~zel (ft~ -Panels
Control Da pcrs One (inspection) 203 One 300 mm x 200 mm Both sid Fire Dampers One (sCTjdJl~) 20211 One 300 0101 x 200 mm One side HeatingCooling Coils One (inspedion) 20213 One 300 mm x 200 mm (lIpstream) Both sides Attenuators (rectangular) None required One 300 mm x 200 mm (downstream) Both sides Attenuators (circular) one retluired One 300 mm x 200 mm (downstream) One side Filter Sections One (inspection) 20212 one required Uoth sides Air Turn Vanes None requjred None required Both sides Changes of Direction None required one required One side In-Duct FansDevices One (inspection) 20213 None required Both sides l
1 In the absence of any indication by the designer only Level ) access will be jncorporated into a new ductwork system
2 Tbe panel izes associated with Lev lis I and 3 acee s ar e middottablished by reference to Section 20 of DW144 and Section 2 ofTRll7 respectively
57
DW154 Speclfifatio for Plastics Ductwork
pA XE
B-bliography Included in this Bibliography are technical pUblications which may be of interest (0 ductwork designers fabricators and erectors and to tho e in the heating ventilatlng air conditioning industries generally nquiric should be made of the relevant organisation at the address quoted Since its publication other addresse contained within 0V154 mav have changed and some pubJicalions may have been superseded
HEATING AND VENTILATING CONTRACTORS ASSOCIATION
4 Palace Court London W2 4JG Telephone 020-7229 2488 Fax 020-7727 9268
Orders fo FlY A Publications Old Matlsion House Eamont Bridge Penrith Cumbria CA 10 2BX (Telephone 01768 864771 Fax 01768 86718) Email hvcapoblicationshvwelfarecouk DWn 44 pe ilicatiun for sheet mctal duclwork (Iow- mediulllshy
and high-pressure) 1998) DWIl4 A practical guide to dUGI ork I akage te ting
(revised 2000) DWII54 Specification for plastic~ duct rk DW171 Guide to good Practice for kitchen venlibtion system DW191 Guide to good pracuce glass fibre ductwoJk DwrrMI Acceptance cheme for new products - Redangolar cro
joint classification Guide to good pra tice - Internal cleanliness of new ductwork installations Guide to good practice for the design for the Installation of lire and smoke uampers
J 1Other puhlications
HampV safely guide 5th edition JS2 Tool box talks JS5 Weldlng Safety booklet JSI9 afety facts bo klet Fact sheets 1-24 2nd edition JS2J COSHH manual volume 1 Advice on compliance with the
regulations 1521A CO I-rH manual volume 2 Asses mcnt h ets JS23 Ri k management manual TR3 BrazinltT and bronze welding of copper pipework cUld sheet
(I 976) TR5 Welding of carbon steel pipework (1980)
TR6 Guide to Good Practice for Site Pre sure Testing of Pipework (19 0) Guide to good practice cleanliness of ventilation Ylem
CHARTERED IN TITUTlO OF BUILDING SERVICES E G EERS Delta House 222 Balham High Road London SW12 9BS rTelephone 020-8675 5211 Fax 020-8675 5449) CIBSE Guide Volume A Design Data Volume B In tallatiol1 and quipment Data Volume C Reference Data
CommlssioniJIg Codes These Codes eover the preliminary checkS eUing to work and regulation of vanous catcgories 0 plan The Codes give a guide to design implications Series A Air Distnbution Systems Series B Boiler Plant
ri s C Automatic Conlrol ystems Cr1es R Refrigerating Sy terns
Sene iN Water Distribution Systems
Technkal Memonllda TM 4 Design Notes for the Middle East TM bull Design otes for Ductwork TM 13 Minimi iog lhc Risk of egiounaires Disease
Research Reports RROI95 Ventilation system hygiene - A review of published
infomlatioo on lhe occurrence and ffects of Olltamination Rl~02J95 Air-to-air heal rec v ry RR0395 rnfluen e of HV C on smoke detectors
ATlONAL ENI [ERING SPECIFICATION LfMITED Southgatc hamber 3739 Southgate Street Winchester S023 9EH (Telephone 01962 842058 Fax 01962 R(8982) BUfLDING S RVICES RESEARCH AND [ ORMATION ASSOCIATIO Old Bracknell Lane West Bracknell Berkshire RG 12 4AH (Telephone Brackl1eU (01344) 426511 Fax 01344 487 -7 )
Application Guides AGln4 De tglJing Vana~le Volume middotylans for KOOnl
iir Movement AG1I91 Commissioning of V Sylcms in Buildings 11 6194 Fire Dampers
B) 94 cntiJalion or KitcneTls
AG389 The Commls ionin of Air Systems In Buildmgs AH2192 Commissioning of Bern - A ~ode of Practice TN2417 I Fire Dampec il) Ventilating Ducl
BEATING VENTILATING A AIR CONDITION G MA UFACTURERS ASSOCIATIO (HEVAC) HEVAC Henley Road Medmenham Marlow Buck SU 2ER (Telephone 01491 578674 ox 01491 575024 Emoimiddot infofetacouk)
Publicatjons Air Diffusion Guide Guide to Air Handling Unit Leakage Testing Guide to Good Practice Air Handling Unit Real Room Acoustic ~ st Procedure Specification for the ertiiicatioll ofAir Filters Method of Test for Water Rejection PerfOnTlatce of Louvrcs Subjected 1(1
Simulated Rainfall Test Procedure for Acoustic Loo cs Specification 10 Floor GrilJes - Types Performan e and Method ofTest Specification for the Determination of the Collection Efficiency of SilJ1d
Trap Louvre Domestic Mechwlical Vclltllalion Systems with Heal Recovery Fan Application Guid
~an and Ouctwork Installation Guide Guide to Fan Noise and Vibration
pecification of Requirements for JallJral Smoke and Heal Exhausl Ventilators
pecification for Powered Smoke and Heat Exhaust Ventilators
Specification of Requirements for Smoke Curtains Design Gujue of Smoke Ventilation for Single Storey Lodustrilll Building~
Including those with Mezzanine Floor and IIi Racked Storage Warehou es - Issue 3
Guidance for the Design of Smoke entilation YSlem for Covered and Undergrollnd Car Parks - lssue 1
Application of SOloke Control Equipment and Syst m Guid to Good Practice - Isue J
58
DW154 Sp(C~tiifitiol for Plastics Ductwork
BRITISH STANDARDS INSTIT TION Sales Department 101 P ntooviLle Road London NI 9ND (felephone 020-78 1 78801)
CP 413 1973 Ducts for building ervices
SS 476 Fire tes on building matenals and lruc(ure
Part 4 19 4 Non-combustibility lest or materials
Part 6 I Fire propagation lest for materials
Part 7 1993 Surface spread of tlarnJ tesls for materia
Part 20 1987 Fir resistance of elements of construction
Part 21 1987 Fire r sistlUlce of loadbeanng elements of construction
Part 22 1987 Fhe istallceofllon-loadbearing elemcllts ofconsttuclion Part 23 1987 Contribution of componcnts to the fire resistance 0 a
structure
Part 24t987 Fire resi lance of wl1lilation ductl
SS 5588 nan 919 0 Fire Precautions III thc desIgn and OOSlnJ lion of buildings
S 729 1971 Hot dip galvanized oatiugs (or irOIl aod stcel articles
BS 1449 Steel plate sheet and Irip
Pan 11991 Carbon steel plate heel and strip Part 2 1983 Stainless steel plate sheer and strip
and
B middotENJOI49-2 996 BSEN 10149- 1991)
BSEN 10131 1992
BSEN22063 Sprayed metal coarings 1994 Protection of iron and steel by aluminium and zinc against
atmospheric cOlosion Irotectiotl of iron and ste I against corro ion and oxishydation at elevared temperatures
BS 353 1981 Glossary of lerms relnting to thermal insulation
BS ISO 1479 Self-tapplngscrewsandmetallicdri c crew
B -lSO 7049
1994
B 4800 1989 Painl colour for building purposes B 4848 l0 rolled structural steel sections
Part4 1972 Equal and unequal angles BS 5422 1990 Specification for the use of therm illuating matcriulS
SS 5720 1979 ode of practice for mechanical veutilating and air C 11shy
dirionin bull in building
l3S PR 12814-1 Bend resting for plasric welds
SS PR 12814-2 Tensile testing for plastic welds
SS PR 13067 Appro altesting for plastic welds
BS PR EN I 100-] Vi ual in pection ofplaslic welds
SHEET METAL AND AIR CONDITIONING CONTR-CTORS NATIONAL ASSOCIATION INC (SMACNA) Headquarters 420 I Lafayeue Center Drive Chanlilly Virginia 2051-1209
Mailing Address pa Box 221230 Cbantilly Virginilt120 153-1230
Telephone (703) 803-2980 Fax (703) 803-3732
Accepted IJJdustry Pl3Gtice for Industrial Duct Constnlelion 197 ) i-rchitecmral Sheet kwl Manual ([993)
Comractors Guide lor Modification 10 ooslruerion Colllraets 1993 Ducted Eleclric Heat Guide for ir Handling Ssrerns (1994)
En~rgy ollservatioD Guidelines (1984) Energy Recovery Equipment yslClllS (199l
Fibrou GIns Duct onS1ntClion Standards (1992)
Fire Smoke amp Radiation Damper In tall Guide for HVA Syst ms (1992) Guide t leel Stack 1(95)
HVA Air Duct Leakage Test Manual (19 ) HVA COlllmissioning lvlanual (1994)
H A Duct Construction Standards-Metal amp Flexible (1995) Addendum 01 (Nov 1997)
HVA Duct Systems Inspection Guide (1989)
HVA ySlems-Application (1986) nVAC ByternS-DLlct D ign (1990)
HVi Systems-Testing Adjusting amp Balancing (1993)
indoor Air Quality Manual (1993) tcheu quipment Fabrication Guidelmes (1990)
Managers Guide for elding (1993)
Rectangular Industrial Duct Cons1TUction Standards (19 0) Round Industrial Duct oustmction Standards (1977)
Sei mic Restraint Manual (1991) (wl Appendix E 1993) SMACNA Ma le Index ()fTechnical Publications (1995) Tbennoplnstic Duct CPY ) Construction Manual 1994)
DEPARTME OF THE ENVIRO MENT (Publications Centre) H Stationery Oflice 5 Nine Elms Lane London SWS 5DR
MampEJ 011972 Electrical in tallat1011 in buildings ( ew Editiou)
IampE 0319 Healing hot and cold wat r steam and gas losla1lations for buildings
M amp - No4 1970 Central heating and hot and cold ~ ateT in tallations for
dwelling
M amp ENo100 1971 Mechanical ventilation for building~
ASSOCIATION FOR SPECIALIST FIRE PROTECTlO As ociation House 235 Ash Road AJdershot Hampshire GUl2 4DD
Telephone OJ25221322 Fax 0 J252 333901
lublicalioos Fire Ratcd and moke Outlet Ducrwork An Industry Guide t Design and InSlalla lioll
HEALTH AND SAFETY EXEC TIVE Rose Court 2 Southwark Bridge London SEl 9HS Telephone 020-7717 6000
TWJ THE WELD G TlTUTE Abington Hall Abington Cambridge CB16AL Telepbone 0 J223 89162
Publication DatJ Oil w~ldll1g of lhermopla lics
59
DW154 wciiwlioll for Plastics Ductwork
A -=--DIX
Factors
Specific gravity shy pp = 091 approx UPVC = 14 approx
Some miscellaneous conversion factors
To convert
Length Inches to millimetres Feet to metres
Multiply by
2540 03048
To convert
Millimetres to inches Metres to feet
vIultiply by
003937 3281
Area Square inches to square millimetres 6452 Square millimetres to square inches 000155 Square feet to square metres 00929 Square metres to square feet 10764
Volume Cubic feet to cubic metres Cubic feet to litres Gallons (UK) to litres
002832 2831 4546
Cubic metres to cubic feet Litres to cubic feet Litres to gallons (UK)
35315 00353
022
Mass Ounces to grams Pounds to kiJograms Tons to tonnes
2835 04536
1016
Grams to ounces Kilograms to pounds Tonnes to tons
003527 2205
09842
Volume flow Cubic feet per minute to cubic Cubic metres per second to cubic
metres per second 0000472 feet per minute 2119 Cubic feet per mIDute to litres Litres per second to cubic feet
per second 04719 per minute 2119
Motion Feet per minute to metres per second 000508 Metres per second to feet per minute 197
Pressure Inches water gauge to millibars 2491 Inches wateJ- gauge to pascals (Pa) 2491 I Pa = I ewton per square metre = 10-2 millibars
60
Heating and Ventilating Contractors Association Esca House 34 Palace Court London W2 4JG
Tel 020 7313 4900
e-mail contact Itvcaorguk web site wwwhvcaorguk
Fax 020 7727 9268
DW154 Specificatioll for Plastics Ductwork
each class of duct llnd r operating condition will be io the region of CIa S A low pressure 6 Clas B medium pres un 3 Clas C high pressure 2
A5 SPECIFYING AIR LEAKAGE TESTING Re peeting both the co -t and programme implications a sociated with te ling du 1 for leakage the designer may for example indicate that a particular system is te ted as follow
a) High pressure ducts - all tested b) Medium pr ssure duets - 10 of the
ductwork shall be s eet d at random and tested
c) Low pre sure - unte ed In any case where a random te t i elected for medium pre sure ductmiddot the followin c1au~e is suggested for inclusion by the de ign r
The designer hall elect at random a maxirnwlI of 10 of the dUCl system to bt tested for air leakage The duct hall be tested af the pressure recommended in Table J3 for the assifi atiol for the ectiol1 of the ductwork that is to be tested The tests shall be carried Ollt as the work proceeds and prior to the application of thermal insulation In the event of test failure of the randomlY selected section the designer shall have The right to select two La1her e tiolls at random for resting Where succes ive failures are identified there shall be a Tight to require rhl COl11raCWr 10 apply remedial attention to the complete ductwork system Th contractor shall provide documented eviden e of the calculalions used to arrive (1
the allowable 10 I for the section to be tested and the client or his agent shall willess and sign the results of the test
able 13 Air leakage rates
Maximum leakage of duct work Static
prcssUft Low-pressure edium-prc-sure I Iigh-prebull me diJfercntial Class A Class B Class C
1 2 J 4 Pa Litres per second per quare metre of surface area 100 054 018 ZOO 084 028 300 110 037 400 132 044 500 153 051 600 058 019 700 064 021 800 069 023 900 075 025
1000 080 027 1100 1200 1300 1400 1500
029 030 032 033 035
1600 1700 1800 1900 2000
036 038 039 040 042
Note Recommend d mean test presures are highlighted iD bold type with the actual selection being left to tll test operator
50
DW154 Sfeeiieaioll for Plastics Ductwork
A9
A10
and air leakage classification for the y em under test
DESIGNERS CALCULATIONS The designer can middotaJculate with reasonable accuracy the predicted total loss from a ystem by
a) Calculating the operatin presure in each ection of the sy tern
b) Calculating the surface area of the ductwork in each correspondin pre lire s ction
c) Calulating the allowabl~ los at the operating pressure for each ection of the system (see table 13 for allowable leakage figures)
VARIABLE PRESSUR S IN SYSTEMS De igner can achieve significant co t saving by matchina operating pressures throughout the system to constmctional standard and appropriate air leakage testing eO the practice of specifying construction tandards for whole duct sy tems based on fan discharge pre sure may incur unnece sary costs on a project For example ome large sy terns ould well be classiC ed for I akage limits as follows
Plant room risers CJas C Main floor distriblltJou CIa B Low pre sure outlets Cla A
A6 SPECIAL CASES There may be ~itLlations on a project where circumstance dictate thal pecial consideration be given to containing air loss s eg a long mn of duclwork may incur a di -proportjonate level of air 10 s In ca es such as thi example the designer can specify an improved tandard of airtighmess ie 80 of alJo~able 10 s for la B Ju ts The designer sbould not specif a CIa C t sI at CIa s C pressure for a CIa s B ducl
A7 SUGG S ED RANGE OF TES ING
A8 TESTING OF PLANT ITEMS Items of inline pJant (eg Fig 106 to 115) will not normaUy be included in an air I akage test The dllctwork contractor may indud such itelllS in tbe te t jf rh quipm ot has a certificate of COnfOlnlity for Ihe pres ure clas
bull High pressure duct bull Medium pre sure ducts bull Low pre sur ducts bull Exposed extract syst ID bull Ceiling void extract
systems bull Secondary ducts from
VAV or fan coil units bull Flexjble duct bull Final connections and
branches to grille and diffusers
100 test See A5 Untested UDt sted
Untested
Untested Untested
Untested
SI
i
DW154 SJecijicafion for Plastics Ductwork
ig 116 Permitted leakage at various pressures
Leakage in litres per second per square metre duct surface area
Vgt
o ltgt 0 ltgt N
ltgt Cgt
0 0 cc
0 0
~
g =
g ~
c 0
J
ltgt 0 I
~ ] tn
ltgt ltgt
In ol
~ 0 ~ 8 ~
~
c ltgt ltgt
~ CJ
~ ~ ~ ~ 8
0shyij
~ ~ ~ t
ltgt ltgt 00
l
~
~ Q
c C
~ rshy
e ltgt
I 1
I Cgt ltgtv
c Co ~
~~ ~ 10
I
0 Cgt
fJshyq 410 ) 1 ltgt
ltgt N
~ shy ltgt ltgt
~ I 1
c
52
DW154 Specificatio for Plastics Ductwork
Example of a completed test sheet Test No
General
Name of job N~ jC43Pt(r2lef Building Repound ~(~~0
Part 1 - Physical details
a Section of duct work to be tested ~(diffPIfff~el1f3rd Floor
b Drawing Number g91~~ c ssure aSSJ L atlOn V~Jl~IRfYgtg~~lPre Cl T Class C
d Test static pressure -(9 raErq~ ~~~~-~~J~~~ ~~ ~~~~ll
Leakaoe factor 9~-tre3$ecMz I OM REFTOTABLE 13)e b bullbullbullbullbullbullbull
f Surface area of duct under test Q~tJJItetre$ CPROMCALCU TIO BELOW)bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull ampampamp bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull
g ]Vlaxi mum permitted leakage -~ (~i~~0 ~~r~~ ~~~l-~-11~ ~~~Q
Part 2 - Test particulars
a Duct static pressure reading 9QFt~q~ ~ middot~~~1 ~~
b Manufacturer and type of liow measuring d vice (-~~~cJ~Y-9Q7EYg c Range of measurement of now measuring device QtP)OQ~(e~~~0I~~~~1~I~ ~~~~~~W~
d Reading of flm measurin o device pmiddot IFROM RIO)ftscag ~
I (DERlVED [ROM CHART SUPPUED WITH RIG US 0 ud)1e Interpreted air flow leakage rate ~(~~~f~~~ (~l~~~~~~~~~~~~~~~~~I
f Duration ~~~~~norn~allY l~ lnil1Ut~~d~~~ it1~ W~ Date of test ~(lITled ut by Wltll s ed by ~ ~
(~lJ MIJLrr) (Si~rrfltJUYJ
Printed Name 1~g0f~ Printed Name ~~Y~9~ and Company 7jl~~~~~( UJd CompanY AB COII$Itallt8
Width and depth or diameter
Periphery ength Area
millimetreS millimetres metre qL1are metre
800 x 750 3100 1755 5440
600 x 650 2500 557 1193
300 x 300 1200 120 144
305 din 958 700 670
250 dia 785 450 353
TOTAL 8000
53
DW154 Specijilarion for Plastics Ductwork
pA XB
Guida ce No es For he ransport Handling and
Storage of uctwork
avoid damage to adjacent duct panels In somc ca es particularly on con acts calling f r repetitive sizes the use of timber jigs and spacers may be justified Where reduced bulk and greater protection are major factor such as consignments for export transporting ductwork in L shape sections may justify the increa ed ite as embly co ts
It is recommended that before a contract is finalised that consideration is given to the subject of site acces material handling and storage as tbcy havgt a strong influence on the cost efficiency of the overall activity of ductwOlk installation
B3 Handling To minilnise th risk of damage duct sections should be clearly identified and deliveries to site should be closely linked to the installation programme so as to avoid accumulation of
B1 Storage and Handling of Ra Material Material should be stored in suitably designed racking out of direct unJight Where possible the e racks should be metal to earth Edges of cut she t may be harp and protective gloves are advised Wearing teel toe-capped boots is recommended Most pIa tic sheet is manufactured with smootb mfaces andor is suppLied with protective coating Care must be taken to prevent accidental lippag of stacked materials Beiuoshy good electrical insulators the movement of stock unless earthed will allow the build up of stati All stock shapes are chemically stable at normal temperature Whil t some raw materials used in their manufacture may themselves pre ent a toxic hazard once incorporated into the lOck bape they no long r constitute such a hazard and no dermatitic bazard are known nor are any
unfiJied ductwork and minimise double handling It is important to recognise that ductwork panels joint and corners arc susceptible to damage and care must be taken wheu band ling such material through a site During handling individual item of duct work may be liable to light cross sectional deformation until thev become an integral pan of a completed ductwork system Whilst this may temporarily detract from its intended appearance thi deformation will not have any detrimental effect on the functionality of the finally a semblecl system Installation of duct work and asociated plant items ill illevitably involve manual handUng The responsibi Iiry of employers and employees to a ses the risk of personal injury during mallual handling operations is et out in the HS E publication L23 Guidance on Manual Handling Regulations 1992
environmental problems expected 84 Site storage
B2 fransport Large capacity vehicles with high-sided open or closed-top bodies are tlle mo t suitable for the transport of dllctwork Careful consideration should be given to the
Adequate floor space IDust be provided within tbe building for the site storage of ductvork Such storage shalt make due allowance for thc stOf(ne of ductwork in stacks such that access ~ egt
between them is of sufficient width to pennil the removal of item without interference to
unloading of transport on sit a not all siJes b n fit from the material handlino- and access facilities that exi [ in a manufacturing workshop such as crane- fork-lifts or loading bay Site handJiog facilities along with
adjoining sta ks Ductvork components should be positioned so a to avoid crushing Ductwork of small panel size may be stored horizontally however care should be exercised to ensure that tack sizes are limited 10 within
ehicular acce s restrictions may itilluence the type and ize of transport to be uWised
engtlls of ductwork should be positioned 0
the tmctural strength of the duct sections to prevent distortion of the lower sections within the stack
as to avoid crushing Lengths Witll projections such as branches and bends i1anges girths damper quadrauL should be loaded so as to
54
DW154 S1tciic(ltioll for Plastics Ductwork
85 Internal cleanliness of new ductwork The site storage of ductwork introduces the important cODsideration of maintaining the internal cleanliness of the ductwork R feren e should be made to HVCA documentshybull DWffM2 Guide to Good Practice - internal
Cleanliness of New Ductwork Installations If the above conditioDs can not be satisfied consideration should be given by tJle designer to amending the specification to include for Po t Installation Cleaning as covered by tJ1C HVCA documentshybull TRJ17 Guide to Good Practic - Cleanliness
of Ventilation Systems
APPE DIXC
Fi e Retardant inishes C1 Improvement in the fire retardancy of plastic
ducts can be achieved to varying degrees and is wholly dependent llPOll the surface coating laminating resin selected and construction specification adopted In some instances smoke emission is coILSidered equaUy with other speci fication requirernen ts of the materials resistance to ignition and bumjng It is therefore important for design rs to establ ish the clients and officers detailed requirements and not rely on a tbird party interpretation of fire resisting or fire retardant Where possible the specification should refer dir etly to compliance with a British or European Standard identifying the specific sections applicable There are various types of resin and mat rcLnforcements that can achieve a Class 1 surface spread of flame ratin o when tested according to BS476 Part 7 (1987) This test puts materials illto Class I - 4 in descending order of perfoDllance according to the rat and extent of flame spread over their surfac under standard beating conditions Materials should also be tested for flre propagarion to BS476 Part 6 (1989) Tbi tesr measures the amount and rate of heat evolved by the material when subjected to standard heating
conditions Test results are given as an index of Perfonnance (i) whicb is based on three sub indices (iJ (i1) (h) The higher the value of the Index of Performance (i) the greater is the material s contribution to fire growth The higher the value of the sub-index 0) rhe greater the ease of ignition aod flame spread The highest product performance classification as defined in Approved Document B of the Building Regulations is Class O This is acLlieved if a material surface of a composite ploduct i~ either a) composed throughout of materials of
limited combustibility or b) a Class I material which has a tlre
propagation index (i) of not more than 12 and sub-index (i l ) of nor more than 6
01 J Class 0 is not a cla$sif1cation identified in any British Standard test
There are resin system reported to be classified to Class O when tested to BS476 Pcl1S 6 and 7 however designers need to ensure that such sysrems can be applied to their proposed design In propriety resinmat system available the fabrication techniques and COITect application are critical to the integrity of the reinforcing and clas ificatiol1 For example in some systems the u e of a non-fire retardant gelcont on a fire retardant substrate would reduce the classification For further information see HVCA publication DW144 Appendix D
55
DW154 SplCijiClIliol1 for Plastics Ductwork
x Guidance otes For nspectmiddoton Servicing a d
Clean-ng Access Openings
D1 GE ERAL This appendix highlight in ummary fOI111
the acce considerations that hould be made by the design r iD terms of inspection servicing and cleaning Having considered the seop and the design of the dUCI work system relative to the guidelines outlined below the designer should clearly indicate which levels of acces should be incorporated into the manufacture of a new duct work system (See Table 14 and Note I b low it
D2 DESIGN CONSIDERATIONS
D21 In ptction and servicing requireshyments are set out in Section 15 of Lhis specification
D22 Cleaning requirements are set out in the HVCA pubUcation TRl7 Guide to Good Practice Clean Lines of Ventilation Systems and the guide tates The precise location ize and
type of access would be dependent on the type of ductwork cleaning inspection and te ting metbods to b adopted Care protection and standards of cleanliness prior LO cOlllmisionin o
are set out in th AV A publication DWITM2 Guide to Good Practice Internal Cleanliness of New Ductwork Installations and th guide state Wh re specific limits of cleanliness are required ductwork sball be cleaned after installation by a spcialist cleaning contractor It will b in the interests of tht desioner botb financially and practically to cunsider employing a specialist c1eauing contractor at tbe
outset of a contract to internally clean newly installed ductwork prior to bandover This approach would reali e the following benefit shyi) Tb actual numb r of cleaning
access panels could be detennined to suit the method of cleaning to be adopted (This may be 1 s than the maximum requiremen listed under Lev 13 of Table 14)
ii) Clear directions could b given to the ductwork contractor as to tJle size and location of cleaning access panels that are required to be fitted during the mauushyfaclunng pro s
iii) The specialist cleaning operation prior to commi ioning vould enable the cleaning contractor to verify the practical acee requirement for the future cleaning operation associated -vitb a regular maintenance programme
iv) A specialist cleaning operation prior to commissioning would allow the designer to omit from the speeilicatiolJ the DWrrM2 requirem nt for factory sealing protection wipe downs and capping-off
v) Specialist Ieall ill 0 to the measurable standard defin d in TR17 will allow an objective definition of cleanline to be achieved
Car ful consideration must be gIven by the designer to the practl aJ problems associated witb the manufacture and fitting of suitably si Led access panel on small cross section duct and on the circular faces of rouod and flat oval ducts in particular
D23 Special con ideration must be given by the de igner to the practical problems associated with gaining personnel access to heavily congested ceiling areas and multi-la red du twork systems This approach would avoid
56
DW154 Spfciication for Plastics Ductwork
the possibility of access panels being D3 ACCESS 0 IN-LINE EQUIPMENT incorporated into a ductwork system at the This appendix unly covers acc il1spection manufacturing stage that were later found in through the ductwork body adjacent to an item practice to be inaccessible for either ervicing of in-line equipment and not openings in the or cleaning activities equipment itself
able 14 Acce requirements for inspection servicing and cleaning
HVCA PUBLICATIO REFE NeE (uidtgt 10 Gund Prartict
Adjace t OW144 Cleanliness orVcnlillltio S~lcr~ fRjJ7
in-line LeyeJ 1 Level 2 Level 3 ite sequipment pcdionSen lcin~ Section d C1eaniJl( SUn(O)lnspc lion Palle ltk~m_n
2011 (minimum OiL Jubje-ct to duct ~zel (ft~ -Panels
Control Da pcrs One (inspection) 203 One 300 mm x 200 mm Both sid Fire Dampers One (sCTjdJl~) 20211 One 300 0101 x 200 mm One side HeatingCooling Coils One (inspedion) 20213 One 300 mm x 200 mm (lIpstream) Both sides Attenuators (rectangular) None required One 300 mm x 200 mm (downstream) Both sides Attenuators (circular) one retluired One 300 mm x 200 mm (downstream) One side Filter Sections One (inspection) 20212 one required Uoth sides Air Turn Vanes None requjred None required Both sides Changes of Direction None required one required One side In-Duct FansDevices One (inspection) 20213 None required Both sides l
1 In the absence of any indication by the designer only Level ) access will be jncorporated into a new ductwork system
2 Tbe panel izes associated with Lev lis I and 3 acee s ar e middottablished by reference to Section 20 of DW144 and Section 2 ofTRll7 respectively
57
DW154 Speclfifatio for Plastics Ductwork
pA XE
B-bliography Included in this Bibliography are technical pUblications which may be of interest (0 ductwork designers fabricators and erectors and to tho e in the heating ventilatlng air conditioning industries generally nquiric should be made of the relevant organisation at the address quoted Since its publication other addresse contained within 0V154 mav have changed and some pubJicalions may have been superseded
HEATING AND VENTILATING CONTRACTORS ASSOCIATION
4 Palace Court London W2 4JG Telephone 020-7229 2488 Fax 020-7727 9268
Orders fo FlY A Publications Old Matlsion House Eamont Bridge Penrith Cumbria CA 10 2BX (Telephone 01768 864771 Fax 01768 86718) Email hvcapoblicationshvwelfarecouk DWn 44 pe ilicatiun for sheet mctal duclwork (Iow- mediulllshy
and high-pressure) 1998) DWIl4 A practical guide to dUGI ork I akage te ting
(revised 2000) DWII54 Specification for plastic~ duct rk DW171 Guide to good Practice for kitchen venlibtion system DW191 Guide to good pracuce glass fibre ductwoJk DwrrMI Acceptance cheme for new products - Redangolar cro
joint classification Guide to good pra tice - Internal cleanliness of new ductwork installations Guide to good practice for the design for the Installation of lire and smoke uampers
J 1Other puhlications
HampV safely guide 5th edition JS2 Tool box talks JS5 Weldlng Safety booklet JSI9 afety facts bo klet Fact sheets 1-24 2nd edition JS2J COSHH manual volume 1 Advice on compliance with the
regulations 1521A CO I-rH manual volume 2 Asses mcnt h ets JS23 Ri k management manual TR3 BrazinltT and bronze welding of copper pipework cUld sheet
(I 976) TR5 Welding of carbon steel pipework (1980)
TR6 Guide to Good Practice for Site Pre sure Testing of Pipework (19 0) Guide to good practice cleanliness of ventilation Ylem
CHARTERED IN TITUTlO OF BUILDING SERVICES E G EERS Delta House 222 Balham High Road London SW12 9BS rTelephone 020-8675 5211 Fax 020-8675 5449) CIBSE Guide Volume A Design Data Volume B In tallatiol1 and quipment Data Volume C Reference Data
CommlssioniJIg Codes These Codes eover the preliminary checkS eUing to work and regulation of vanous catcgories 0 plan The Codes give a guide to design implications Series A Air Distnbution Systems Series B Boiler Plant
ri s C Automatic Conlrol ystems Cr1es R Refrigerating Sy terns
Sene iN Water Distribution Systems
Technkal Memonllda TM 4 Design Notes for the Middle East TM bull Design otes for Ductwork TM 13 Minimi iog lhc Risk of egiounaires Disease
Research Reports RROI95 Ventilation system hygiene - A review of published
infomlatioo on lhe occurrence and ffects of Olltamination Rl~02J95 Air-to-air heal rec v ry RR0395 rnfluen e of HV C on smoke detectors
ATlONAL ENI [ERING SPECIFICATION LfMITED Southgatc hamber 3739 Southgate Street Winchester S023 9EH (Telephone 01962 842058 Fax 01962 R(8982) BUfLDING S RVICES RESEARCH AND [ ORMATION ASSOCIATIO Old Bracknell Lane West Bracknell Berkshire RG 12 4AH (Telephone Brackl1eU (01344) 426511 Fax 01344 487 -7 )
Application Guides AGln4 De tglJing Vana~le Volume middotylans for KOOnl
iir Movement AG1I91 Commissioning of V Sylcms in Buildings 11 6194 Fire Dampers
B) 94 cntiJalion or KitcneTls
AG389 The Commls ionin of Air Systems In Buildmgs AH2192 Commissioning of Bern - A ~ode of Practice TN2417 I Fire Dampec il) Ventilating Ducl
BEATING VENTILATING A AIR CONDITION G MA UFACTURERS ASSOCIATIO (HEVAC) HEVAC Henley Road Medmenham Marlow Buck SU 2ER (Telephone 01491 578674 ox 01491 575024 Emoimiddot infofetacouk)
Publicatjons Air Diffusion Guide Guide to Air Handling Unit Leakage Testing Guide to Good Practice Air Handling Unit Real Room Acoustic ~ st Procedure Specification for the ertiiicatioll ofAir Filters Method of Test for Water Rejection PerfOnTlatce of Louvrcs Subjected 1(1
Simulated Rainfall Test Procedure for Acoustic Loo cs Specification 10 Floor GrilJes - Types Performan e and Method ofTest Specification for the Determination of the Collection Efficiency of SilJ1d
Trap Louvre Domestic Mechwlical Vclltllalion Systems with Heal Recovery Fan Application Guid
~an and Ouctwork Installation Guide Guide to Fan Noise and Vibration
pecification of Requirements for JallJral Smoke and Heal Exhausl Ventilators
pecification for Powered Smoke and Heat Exhaust Ventilators
Specification of Requirements for Smoke Curtains Design Gujue of Smoke Ventilation for Single Storey Lodustrilll Building~
Including those with Mezzanine Floor and IIi Racked Storage Warehou es - Issue 3
Guidance for the Design of Smoke entilation YSlem for Covered and Undergrollnd Car Parks - lssue 1
Application of SOloke Control Equipment and Syst m Guid to Good Practice - Isue J
58
DW154 Sp(C~tiifitiol for Plastics Ductwork
BRITISH STANDARDS INSTIT TION Sales Department 101 P ntooviLle Road London NI 9ND (felephone 020-78 1 78801)
CP 413 1973 Ducts for building ervices
SS 476 Fire tes on building matenals and lruc(ure
Part 4 19 4 Non-combustibility lest or materials
Part 6 I Fire propagation lest for materials
Part 7 1993 Surface spread of tlarnJ tesls for materia
Part 20 1987 Fir resistance of elements of construction
Part 21 1987 Fire r sistlUlce of loadbeanng elements of construction
Part 22 1987 Fhe istallceofllon-loadbearing elemcllts ofconsttuclion Part 23 1987 Contribution of componcnts to the fire resistance 0 a
structure
Part 24t987 Fire resi lance of wl1lilation ductl
SS 5588 nan 919 0 Fire Precautions III thc desIgn and OOSlnJ lion of buildings
S 729 1971 Hot dip galvanized oatiugs (or irOIl aod stcel articles
BS 1449 Steel plate sheet and Irip
Pan 11991 Carbon steel plate heel and strip Part 2 1983 Stainless steel plate sheer and strip
and
B middotENJOI49-2 996 BSEN 10149- 1991)
BSEN 10131 1992
BSEN22063 Sprayed metal coarings 1994 Protection of iron and steel by aluminium and zinc against
atmospheric cOlosion Irotectiotl of iron and ste I against corro ion and oxishydation at elevared temperatures
BS 353 1981 Glossary of lerms relnting to thermal insulation
BS ISO 1479 Self-tapplngscrewsandmetallicdri c crew
B -lSO 7049
1994
B 4800 1989 Painl colour for building purposes B 4848 l0 rolled structural steel sections
Part4 1972 Equal and unequal angles BS 5422 1990 Specification for the use of therm illuating matcriulS
SS 5720 1979 ode of practice for mechanical veutilating and air C 11shy
dirionin bull in building
l3S PR 12814-1 Bend resting for plasric welds
SS PR 12814-2 Tensile testing for plastic welds
SS PR 13067 Appro altesting for plastic welds
BS PR EN I 100-] Vi ual in pection ofplaslic welds
SHEET METAL AND AIR CONDITIONING CONTR-CTORS NATIONAL ASSOCIATION INC (SMACNA) Headquarters 420 I Lafayeue Center Drive Chanlilly Virginia 2051-1209
Mailing Address pa Box 221230 Cbantilly Virginilt120 153-1230
Telephone (703) 803-2980 Fax (703) 803-3732
Accepted IJJdustry Pl3Gtice for Industrial Duct Constnlelion 197 ) i-rchitecmral Sheet kwl Manual ([993)
Comractors Guide lor Modification 10 ooslruerion Colllraets 1993 Ducted Eleclric Heat Guide for ir Handling Ssrerns (1994)
En~rgy ollservatioD Guidelines (1984) Energy Recovery Equipment yslClllS (199l
Fibrou GIns Duct onS1ntClion Standards (1992)
Fire Smoke amp Radiation Damper In tall Guide for HVA Syst ms (1992) Guide t leel Stack 1(95)
HVA Air Duct Leakage Test Manual (19 ) HVA COlllmissioning lvlanual (1994)
H A Duct Construction Standards-Metal amp Flexible (1995) Addendum 01 (Nov 1997)
HVA Duct Systems Inspection Guide (1989)
HVA ySlems-Application (1986) nVAC ByternS-DLlct D ign (1990)
HVi Systems-Testing Adjusting amp Balancing (1993)
indoor Air Quality Manual (1993) tcheu quipment Fabrication Guidelmes (1990)
Managers Guide for elding (1993)
Rectangular Industrial Duct Cons1TUction Standards (19 0) Round Industrial Duct oustmction Standards (1977)
Sei mic Restraint Manual (1991) (wl Appendix E 1993) SMACNA Ma le Index ()fTechnical Publications (1995) Tbennoplnstic Duct CPY ) Construction Manual 1994)
DEPARTME OF THE ENVIRO MENT (Publications Centre) H Stationery Oflice 5 Nine Elms Lane London SWS 5DR
MampEJ 011972 Electrical in tallat1011 in buildings ( ew Editiou)
IampE 0319 Healing hot and cold wat r steam and gas losla1lations for buildings
M amp - No4 1970 Central heating and hot and cold ~ ateT in tallations for
dwelling
M amp ENo100 1971 Mechanical ventilation for building~
ASSOCIATION FOR SPECIALIST FIRE PROTECTlO As ociation House 235 Ash Road AJdershot Hampshire GUl2 4DD
Telephone OJ25221322 Fax 0 J252 333901
lublicalioos Fire Ratcd and moke Outlet Ducrwork An Industry Guide t Design and InSlalla lioll
HEALTH AND SAFETY EXEC TIVE Rose Court 2 Southwark Bridge London SEl 9HS Telephone 020-7717 6000
TWJ THE WELD G TlTUTE Abington Hall Abington Cambridge CB16AL Telepbone 0 J223 89162
Publication DatJ Oil w~ldll1g of lhermopla lics
59
DW154 wciiwlioll for Plastics Ductwork
A -=--DIX
Factors
Specific gravity shy pp = 091 approx UPVC = 14 approx
Some miscellaneous conversion factors
To convert
Length Inches to millimetres Feet to metres
Multiply by
2540 03048
To convert
Millimetres to inches Metres to feet
vIultiply by
003937 3281
Area Square inches to square millimetres 6452 Square millimetres to square inches 000155 Square feet to square metres 00929 Square metres to square feet 10764
Volume Cubic feet to cubic metres Cubic feet to litres Gallons (UK) to litres
002832 2831 4546
Cubic metres to cubic feet Litres to cubic feet Litres to gallons (UK)
35315 00353
022
Mass Ounces to grams Pounds to kiJograms Tons to tonnes
2835 04536
1016
Grams to ounces Kilograms to pounds Tonnes to tons
003527 2205
09842
Volume flow Cubic feet per minute to cubic Cubic metres per second to cubic
metres per second 0000472 feet per minute 2119 Cubic feet per mIDute to litres Litres per second to cubic feet
per second 04719 per minute 2119
Motion Feet per minute to metres per second 000508 Metres per second to feet per minute 197
Pressure Inches water gauge to millibars 2491 Inches wateJ- gauge to pascals (Pa) 2491 I Pa = I ewton per square metre = 10-2 millibars
60
Heating and Ventilating Contractors Association Esca House 34 Palace Court London W2 4JG
Tel 020 7313 4900
e-mail contact Itvcaorguk web site wwwhvcaorguk
Fax 020 7727 9268
DW154 Sfeeiieaioll for Plastics Ductwork
A9
A10
and air leakage classification for the y em under test
DESIGNERS CALCULATIONS The designer can middotaJculate with reasonable accuracy the predicted total loss from a ystem by
a) Calculating the operatin presure in each ection of the sy tern
b) Calculating the surface area of the ductwork in each correspondin pre lire s ction
c) Calulating the allowabl~ los at the operating pressure for each ection of the system (see table 13 for allowable leakage figures)
VARIABLE PRESSUR S IN SYSTEMS De igner can achieve significant co t saving by matchina operating pressures throughout the system to constmctional standard and appropriate air leakage testing eO the practice of specifying construction tandards for whole duct sy tems based on fan discharge pre sure may incur unnece sary costs on a project For example ome large sy terns ould well be classiC ed for I akage limits as follows
Plant room risers CJas C Main floor distriblltJou CIa B Low pre sure outlets Cla A
A6 SPECIAL CASES There may be ~itLlations on a project where circumstance dictate thal pecial consideration be given to containing air loss s eg a long mn of duclwork may incur a di -proportjonate level of air 10 s In ca es such as thi example the designer can specify an improved tandard of airtighmess ie 80 of alJo~able 10 s for la B Ju ts The designer sbould not specif a CIa C t sI at CIa s C pressure for a CIa s B ducl
A7 SUGG S ED RANGE OF TES ING
A8 TESTING OF PLANT ITEMS Items of inline pJant (eg Fig 106 to 115) will not normaUy be included in an air I akage test The dllctwork contractor may indud such itelllS in tbe te t jf rh quipm ot has a certificate of COnfOlnlity for Ihe pres ure clas
bull High pressure duct bull Medium pre sure ducts bull Low pre sur ducts bull Exposed extract syst ID bull Ceiling void extract
systems bull Secondary ducts from
VAV or fan coil units bull Flexjble duct bull Final connections and
branches to grille and diffusers
100 test See A5 Untested UDt sted
Untested
Untested Untested
Untested
SI
i
DW154 SJecijicafion for Plastics Ductwork
ig 116 Permitted leakage at various pressures
Leakage in litres per second per square metre duct surface area
Vgt
o ltgt 0 ltgt N
ltgt Cgt
0 0 cc
0 0
~
g =
g ~
c 0
J
ltgt 0 I
~ ] tn
ltgt ltgt
In ol
~ 0 ~ 8 ~
~
c ltgt ltgt
~ CJ
~ ~ ~ ~ 8
0shyij
~ ~ ~ t
ltgt ltgt 00
l
~
~ Q
c C
~ rshy
e ltgt
I 1
I Cgt ltgtv
c Co ~
~~ ~ 10
I
0 Cgt
fJshyq 410 ) 1 ltgt
ltgt N
~ shy ltgt ltgt
~ I 1
c
52
DW154 Specificatio for Plastics Ductwork
Example of a completed test sheet Test No
General
Name of job N~ jC43Pt(r2lef Building Repound ~(~~0
Part 1 - Physical details
a Section of duct work to be tested ~(diffPIfff~el1f3rd Floor
b Drawing Number g91~~ c ssure aSSJ L atlOn V~Jl~IRfYgtg~~lPre Cl T Class C
d Test static pressure -(9 raErq~ ~~~~-~~J~~~ ~~ ~~~~ll
Leakaoe factor 9~-tre3$ecMz I OM REFTOTABLE 13)e b bullbullbullbullbullbullbull
f Surface area of duct under test Q~tJJItetre$ CPROMCALCU TIO BELOW)bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull ampampamp bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull
g ]Vlaxi mum permitted leakage -~ (~i~~0 ~~r~~ ~~~l-~-11~ ~~~Q
Part 2 - Test particulars
a Duct static pressure reading 9QFt~q~ ~ middot~~~1 ~~
b Manufacturer and type of liow measuring d vice (-~~~cJ~Y-9Q7EYg c Range of measurement of now measuring device QtP)OQ~(e~~~0I~~~~1~I~ ~~~~~~W~
d Reading of flm measurin o device pmiddot IFROM RIO)ftscag ~
I (DERlVED [ROM CHART SUPPUED WITH RIG US 0 ud)1e Interpreted air flow leakage rate ~(~~~f~~~ (~l~~~~~~~~~~~~~~~~~I
f Duration ~~~~~norn~allY l~ lnil1Ut~~d~~~ it1~ W~ Date of test ~(lITled ut by Wltll s ed by ~ ~
(~lJ MIJLrr) (Si~rrfltJUYJ
Printed Name 1~g0f~ Printed Name ~~Y~9~ and Company 7jl~~~~~( UJd CompanY AB COII$Itallt8
Width and depth or diameter
Periphery ength Area
millimetreS millimetres metre qL1are metre
800 x 750 3100 1755 5440
600 x 650 2500 557 1193
300 x 300 1200 120 144
305 din 958 700 670
250 dia 785 450 353
TOTAL 8000
53
DW154 Specijilarion for Plastics Ductwork
pA XB
Guida ce No es For he ransport Handling and
Storage of uctwork
avoid damage to adjacent duct panels In somc ca es particularly on con acts calling f r repetitive sizes the use of timber jigs and spacers may be justified Where reduced bulk and greater protection are major factor such as consignments for export transporting ductwork in L shape sections may justify the increa ed ite as embly co ts
It is recommended that before a contract is finalised that consideration is given to the subject of site acces material handling and storage as tbcy havgt a strong influence on the cost efficiency of the overall activity of ductwOlk installation
B3 Handling To minilnise th risk of damage duct sections should be clearly identified and deliveries to site should be closely linked to the installation programme so as to avoid accumulation of
B1 Storage and Handling of Ra Material Material should be stored in suitably designed racking out of direct unJight Where possible the e racks should be metal to earth Edges of cut she t may be harp and protective gloves are advised Wearing teel toe-capped boots is recommended Most pIa tic sheet is manufactured with smootb mfaces andor is suppLied with protective coating Care must be taken to prevent accidental lippag of stacked materials Beiuoshy good electrical insulators the movement of stock unless earthed will allow the build up of stati All stock shapes are chemically stable at normal temperature Whil t some raw materials used in their manufacture may themselves pre ent a toxic hazard once incorporated into the lOck bape they no long r constitute such a hazard and no dermatitic bazard are known nor are any
unfiJied ductwork and minimise double handling It is important to recognise that ductwork panels joint and corners arc susceptible to damage and care must be taken wheu band ling such material through a site During handling individual item of duct work may be liable to light cross sectional deformation until thev become an integral pan of a completed ductwork system Whilst this may temporarily detract from its intended appearance thi deformation will not have any detrimental effect on the functionality of the finally a semblecl system Installation of duct work and asociated plant items ill illevitably involve manual handUng The responsibi Iiry of employers and employees to a ses the risk of personal injury during mallual handling operations is et out in the HS E publication L23 Guidance on Manual Handling Regulations 1992
environmental problems expected 84 Site storage
B2 fransport Large capacity vehicles with high-sided open or closed-top bodies are tlle mo t suitable for the transport of dllctwork Careful consideration should be given to the
Adequate floor space IDust be provided within tbe building for the site storage of ductvork Such storage shalt make due allowance for thc stOf(ne of ductwork in stacks such that access ~ egt
between them is of sufficient width to pennil the removal of item without interference to
unloading of transport on sit a not all siJes b n fit from the material handlino- and access facilities that exi [ in a manufacturing workshop such as crane- fork-lifts or loading bay Site handJiog facilities along with
adjoining sta ks Ductvork components should be positioned so a to avoid crushing Ductwork of small panel size may be stored horizontally however care should be exercised to ensure that tack sizes are limited 10 within
ehicular acce s restrictions may itilluence the type and ize of transport to be uWised
engtlls of ductwork should be positioned 0
the tmctural strength of the duct sections to prevent distortion of the lower sections within the stack
as to avoid crushing Lengths Witll projections such as branches and bends i1anges girths damper quadrauL should be loaded so as to
54
DW154 S1tciic(ltioll for Plastics Ductwork
85 Internal cleanliness of new ductwork The site storage of ductwork introduces the important cODsideration of maintaining the internal cleanliness of the ductwork R feren e should be made to HVCA documentshybull DWffM2 Guide to Good Practice - internal
Cleanliness of New Ductwork Installations If the above conditioDs can not be satisfied consideration should be given by tJle designer to amending the specification to include for Po t Installation Cleaning as covered by tJ1C HVCA documentshybull TRJ17 Guide to Good Practic - Cleanliness
of Ventilation Systems
APPE DIXC
Fi e Retardant inishes C1 Improvement in the fire retardancy of plastic
ducts can be achieved to varying degrees and is wholly dependent llPOll the surface coating laminating resin selected and construction specification adopted In some instances smoke emission is coILSidered equaUy with other speci fication requirernen ts of the materials resistance to ignition and bumjng It is therefore important for design rs to establ ish the clients and officers detailed requirements and not rely on a tbird party interpretation of fire resisting or fire retardant Where possible the specification should refer dir etly to compliance with a British or European Standard identifying the specific sections applicable There are various types of resin and mat rcLnforcements that can achieve a Class 1 surface spread of flame ratin o when tested according to BS476 Part 7 (1987) This test puts materials illto Class I - 4 in descending order of perfoDllance according to the rat and extent of flame spread over their surfac under standard beating conditions Materials should also be tested for flre propagarion to BS476 Part 6 (1989) Tbi tesr measures the amount and rate of heat evolved by the material when subjected to standard heating
conditions Test results are given as an index of Perfonnance (i) whicb is based on three sub indices (iJ (i1) (h) The higher the value of the Index of Performance (i) the greater is the material s contribution to fire growth The higher the value of the sub-index 0) rhe greater the ease of ignition aod flame spread The highest product performance classification as defined in Approved Document B of the Building Regulations is Class O This is acLlieved if a material surface of a composite ploduct i~ either a) composed throughout of materials of
limited combustibility or b) a Class I material which has a tlre
propagation index (i) of not more than 12 and sub-index (i l ) of nor more than 6
01 J Class 0 is not a cla$sif1cation identified in any British Standard test
There are resin system reported to be classified to Class O when tested to BS476 Pcl1S 6 and 7 however designers need to ensure that such sysrems can be applied to their proposed design In propriety resinmat system available the fabrication techniques and COITect application are critical to the integrity of the reinforcing and clas ificatiol1 For example in some systems the u e of a non-fire retardant gelcont on a fire retardant substrate would reduce the classification For further information see HVCA publication DW144 Appendix D
55
DW154 SplCijiClIliol1 for Plastics Ductwork
x Guidance otes For nspectmiddoton Servicing a d
Clean-ng Access Openings
D1 GE ERAL This appendix highlight in ummary fOI111
the acce considerations that hould be made by the design r iD terms of inspection servicing and cleaning Having considered the seop and the design of the dUCI work system relative to the guidelines outlined below the designer should clearly indicate which levels of acces should be incorporated into the manufacture of a new duct work system (See Table 14 and Note I b low it
D2 DESIGN CONSIDERATIONS
D21 In ptction and servicing requireshyments are set out in Section 15 of Lhis specification
D22 Cleaning requirements are set out in the HVCA pubUcation TRl7 Guide to Good Practice Clean Lines of Ventilation Systems and the guide tates The precise location ize and
type of access would be dependent on the type of ductwork cleaning inspection and te ting metbods to b adopted Care protection and standards of cleanliness prior LO cOlllmisionin o
are set out in th AV A publication DWITM2 Guide to Good Practice Internal Cleanliness of New Ductwork Installations and th guide state Wh re specific limits of cleanliness are required ductwork sball be cleaned after installation by a spcialist cleaning contractor It will b in the interests of tht desioner botb financially and practically to cunsider employing a specialist c1eauing contractor at tbe
outset of a contract to internally clean newly installed ductwork prior to bandover This approach would reali e the following benefit shyi) Tb actual numb r of cleaning
access panels could be detennined to suit the method of cleaning to be adopted (This may be 1 s than the maximum requiremen listed under Lev 13 of Table 14)
ii) Clear directions could b given to the ductwork contractor as to tJle size and location of cleaning access panels that are required to be fitted during the mauushyfaclunng pro s
iii) The specialist cleaning operation prior to commi ioning vould enable the cleaning contractor to verify the practical acee requirement for the future cleaning operation associated -vitb a regular maintenance programme
iv) A specialist cleaning operation prior to commissioning would allow the designer to omit from the speeilicatiolJ the DWrrM2 requirem nt for factory sealing protection wipe downs and capping-off
v) Specialist Ieall ill 0 to the measurable standard defin d in TR17 will allow an objective definition of cleanline to be achieved
Car ful consideration must be gIven by the designer to the practl aJ problems associated witb the manufacture and fitting of suitably si Led access panel on small cross section duct and on the circular faces of rouod and flat oval ducts in particular
D23 Special con ideration must be given by the de igner to the practical problems associated with gaining personnel access to heavily congested ceiling areas and multi-la red du twork systems This approach would avoid
56
DW154 Spfciication for Plastics Ductwork
the possibility of access panels being D3 ACCESS 0 IN-LINE EQUIPMENT incorporated into a ductwork system at the This appendix unly covers acc il1spection manufacturing stage that were later found in through the ductwork body adjacent to an item practice to be inaccessible for either ervicing of in-line equipment and not openings in the or cleaning activities equipment itself
able 14 Acce requirements for inspection servicing and cleaning
HVCA PUBLICATIO REFE NeE (uidtgt 10 Gund Prartict
Adjace t OW144 Cleanliness orVcnlillltio S~lcr~ fRjJ7
in-line LeyeJ 1 Level 2 Level 3 ite sequipment pcdionSen lcin~ Section d C1eaniJl( SUn(O)lnspc lion Palle ltk~m_n
2011 (minimum OiL Jubje-ct to duct ~zel (ft~ -Panels
Control Da pcrs One (inspection) 203 One 300 mm x 200 mm Both sid Fire Dampers One (sCTjdJl~) 20211 One 300 0101 x 200 mm One side HeatingCooling Coils One (inspedion) 20213 One 300 mm x 200 mm (lIpstream) Both sides Attenuators (rectangular) None required One 300 mm x 200 mm (downstream) Both sides Attenuators (circular) one retluired One 300 mm x 200 mm (downstream) One side Filter Sections One (inspection) 20212 one required Uoth sides Air Turn Vanes None requjred None required Both sides Changes of Direction None required one required One side In-Duct FansDevices One (inspection) 20213 None required Both sides l
1 In the absence of any indication by the designer only Level ) access will be jncorporated into a new ductwork system
2 Tbe panel izes associated with Lev lis I and 3 acee s ar e middottablished by reference to Section 20 of DW144 and Section 2 ofTRll7 respectively
57
DW154 Speclfifatio for Plastics Ductwork
pA XE
B-bliography Included in this Bibliography are technical pUblications which may be of interest (0 ductwork designers fabricators and erectors and to tho e in the heating ventilatlng air conditioning industries generally nquiric should be made of the relevant organisation at the address quoted Since its publication other addresse contained within 0V154 mav have changed and some pubJicalions may have been superseded
HEATING AND VENTILATING CONTRACTORS ASSOCIATION
4 Palace Court London W2 4JG Telephone 020-7229 2488 Fax 020-7727 9268
Orders fo FlY A Publications Old Matlsion House Eamont Bridge Penrith Cumbria CA 10 2BX (Telephone 01768 864771 Fax 01768 86718) Email hvcapoblicationshvwelfarecouk DWn 44 pe ilicatiun for sheet mctal duclwork (Iow- mediulllshy
and high-pressure) 1998) DWIl4 A practical guide to dUGI ork I akage te ting
(revised 2000) DWII54 Specification for plastic~ duct rk DW171 Guide to good Practice for kitchen venlibtion system DW191 Guide to good pracuce glass fibre ductwoJk DwrrMI Acceptance cheme for new products - Redangolar cro
joint classification Guide to good pra tice - Internal cleanliness of new ductwork installations Guide to good practice for the design for the Installation of lire and smoke uampers
J 1Other puhlications
HampV safely guide 5th edition JS2 Tool box talks JS5 Weldlng Safety booklet JSI9 afety facts bo klet Fact sheets 1-24 2nd edition JS2J COSHH manual volume 1 Advice on compliance with the
regulations 1521A CO I-rH manual volume 2 Asses mcnt h ets JS23 Ri k management manual TR3 BrazinltT and bronze welding of copper pipework cUld sheet
(I 976) TR5 Welding of carbon steel pipework (1980)
TR6 Guide to Good Practice for Site Pre sure Testing of Pipework (19 0) Guide to good practice cleanliness of ventilation Ylem
CHARTERED IN TITUTlO OF BUILDING SERVICES E G EERS Delta House 222 Balham High Road London SW12 9BS rTelephone 020-8675 5211 Fax 020-8675 5449) CIBSE Guide Volume A Design Data Volume B In tallatiol1 and quipment Data Volume C Reference Data
CommlssioniJIg Codes These Codes eover the preliminary checkS eUing to work and regulation of vanous catcgories 0 plan The Codes give a guide to design implications Series A Air Distnbution Systems Series B Boiler Plant
ri s C Automatic Conlrol ystems Cr1es R Refrigerating Sy terns
Sene iN Water Distribution Systems
Technkal Memonllda TM 4 Design Notes for the Middle East TM bull Design otes for Ductwork TM 13 Minimi iog lhc Risk of egiounaires Disease
Research Reports RROI95 Ventilation system hygiene - A review of published
infomlatioo on lhe occurrence and ffects of Olltamination Rl~02J95 Air-to-air heal rec v ry RR0395 rnfluen e of HV C on smoke detectors
ATlONAL ENI [ERING SPECIFICATION LfMITED Southgatc hamber 3739 Southgate Street Winchester S023 9EH (Telephone 01962 842058 Fax 01962 R(8982) BUfLDING S RVICES RESEARCH AND [ ORMATION ASSOCIATIO Old Bracknell Lane West Bracknell Berkshire RG 12 4AH (Telephone Brackl1eU (01344) 426511 Fax 01344 487 -7 )
Application Guides AGln4 De tglJing Vana~le Volume middotylans for KOOnl
iir Movement AG1I91 Commissioning of V Sylcms in Buildings 11 6194 Fire Dampers
B) 94 cntiJalion or KitcneTls
AG389 The Commls ionin of Air Systems In Buildmgs AH2192 Commissioning of Bern - A ~ode of Practice TN2417 I Fire Dampec il) Ventilating Ducl
BEATING VENTILATING A AIR CONDITION G MA UFACTURERS ASSOCIATIO (HEVAC) HEVAC Henley Road Medmenham Marlow Buck SU 2ER (Telephone 01491 578674 ox 01491 575024 Emoimiddot infofetacouk)
Publicatjons Air Diffusion Guide Guide to Air Handling Unit Leakage Testing Guide to Good Practice Air Handling Unit Real Room Acoustic ~ st Procedure Specification for the ertiiicatioll ofAir Filters Method of Test for Water Rejection PerfOnTlatce of Louvrcs Subjected 1(1
Simulated Rainfall Test Procedure for Acoustic Loo cs Specification 10 Floor GrilJes - Types Performan e and Method ofTest Specification for the Determination of the Collection Efficiency of SilJ1d
Trap Louvre Domestic Mechwlical Vclltllalion Systems with Heal Recovery Fan Application Guid
~an and Ouctwork Installation Guide Guide to Fan Noise and Vibration
pecification of Requirements for JallJral Smoke and Heal Exhausl Ventilators
pecification for Powered Smoke and Heat Exhaust Ventilators
Specification of Requirements for Smoke Curtains Design Gujue of Smoke Ventilation for Single Storey Lodustrilll Building~
Including those with Mezzanine Floor and IIi Racked Storage Warehou es - Issue 3
Guidance for the Design of Smoke entilation YSlem for Covered and Undergrollnd Car Parks - lssue 1
Application of SOloke Control Equipment and Syst m Guid to Good Practice - Isue J
58
DW154 Sp(C~tiifitiol for Plastics Ductwork
BRITISH STANDARDS INSTIT TION Sales Department 101 P ntooviLle Road London NI 9ND (felephone 020-78 1 78801)
CP 413 1973 Ducts for building ervices
SS 476 Fire tes on building matenals and lruc(ure
Part 4 19 4 Non-combustibility lest or materials
Part 6 I Fire propagation lest for materials
Part 7 1993 Surface spread of tlarnJ tesls for materia
Part 20 1987 Fir resistance of elements of construction
Part 21 1987 Fire r sistlUlce of loadbeanng elements of construction
Part 22 1987 Fhe istallceofllon-loadbearing elemcllts ofconsttuclion Part 23 1987 Contribution of componcnts to the fire resistance 0 a
structure
Part 24t987 Fire resi lance of wl1lilation ductl
SS 5588 nan 919 0 Fire Precautions III thc desIgn and OOSlnJ lion of buildings
S 729 1971 Hot dip galvanized oatiugs (or irOIl aod stcel articles
BS 1449 Steel plate sheet and Irip
Pan 11991 Carbon steel plate heel and strip Part 2 1983 Stainless steel plate sheer and strip
and
B middotENJOI49-2 996 BSEN 10149- 1991)
BSEN 10131 1992
BSEN22063 Sprayed metal coarings 1994 Protection of iron and steel by aluminium and zinc against
atmospheric cOlosion Irotectiotl of iron and ste I against corro ion and oxishydation at elevared temperatures
BS 353 1981 Glossary of lerms relnting to thermal insulation
BS ISO 1479 Self-tapplngscrewsandmetallicdri c crew
B -lSO 7049
1994
B 4800 1989 Painl colour for building purposes B 4848 l0 rolled structural steel sections
Part4 1972 Equal and unequal angles BS 5422 1990 Specification for the use of therm illuating matcriulS
SS 5720 1979 ode of practice for mechanical veutilating and air C 11shy
dirionin bull in building
l3S PR 12814-1 Bend resting for plasric welds
SS PR 12814-2 Tensile testing for plastic welds
SS PR 13067 Appro altesting for plastic welds
BS PR EN I 100-] Vi ual in pection ofplaslic welds
SHEET METAL AND AIR CONDITIONING CONTR-CTORS NATIONAL ASSOCIATION INC (SMACNA) Headquarters 420 I Lafayeue Center Drive Chanlilly Virginia 2051-1209
Mailing Address pa Box 221230 Cbantilly Virginilt120 153-1230
Telephone (703) 803-2980 Fax (703) 803-3732
Accepted IJJdustry Pl3Gtice for Industrial Duct Constnlelion 197 ) i-rchitecmral Sheet kwl Manual ([993)
Comractors Guide lor Modification 10 ooslruerion Colllraets 1993 Ducted Eleclric Heat Guide for ir Handling Ssrerns (1994)
En~rgy ollservatioD Guidelines (1984) Energy Recovery Equipment yslClllS (199l
Fibrou GIns Duct onS1ntClion Standards (1992)
Fire Smoke amp Radiation Damper In tall Guide for HVA Syst ms (1992) Guide t leel Stack 1(95)
HVA Air Duct Leakage Test Manual (19 ) HVA COlllmissioning lvlanual (1994)
H A Duct Construction Standards-Metal amp Flexible (1995) Addendum 01 (Nov 1997)
HVA Duct Systems Inspection Guide (1989)
HVA ySlems-Application (1986) nVAC ByternS-DLlct D ign (1990)
HVi Systems-Testing Adjusting amp Balancing (1993)
indoor Air Quality Manual (1993) tcheu quipment Fabrication Guidelmes (1990)
Managers Guide for elding (1993)
Rectangular Industrial Duct Cons1TUction Standards (19 0) Round Industrial Duct oustmction Standards (1977)
Sei mic Restraint Manual (1991) (wl Appendix E 1993) SMACNA Ma le Index ()fTechnical Publications (1995) Tbennoplnstic Duct CPY ) Construction Manual 1994)
DEPARTME OF THE ENVIRO MENT (Publications Centre) H Stationery Oflice 5 Nine Elms Lane London SWS 5DR
MampEJ 011972 Electrical in tallat1011 in buildings ( ew Editiou)
IampE 0319 Healing hot and cold wat r steam and gas losla1lations for buildings
M amp - No4 1970 Central heating and hot and cold ~ ateT in tallations for
dwelling
M amp ENo100 1971 Mechanical ventilation for building~
ASSOCIATION FOR SPECIALIST FIRE PROTECTlO As ociation House 235 Ash Road AJdershot Hampshire GUl2 4DD
Telephone OJ25221322 Fax 0 J252 333901
lublicalioos Fire Ratcd and moke Outlet Ducrwork An Industry Guide t Design and InSlalla lioll
HEALTH AND SAFETY EXEC TIVE Rose Court 2 Southwark Bridge London SEl 9HS Telephone 020-7717 6000
TWJ THE WELD G TlTUTE Abington Hall Abington Cambridge CB16AL Telepbone 0 J223 89162
Publication DatJ Oil w~ldll1g of lhermopla lics
59
DW154 wciiwlioll for Plastics Ductwork
A -=--DIX
Factors
Specific gravity shy pp = 091 approx UPVC = 14 approx
Some miscellaneous conversion factors
To convert
Length Inches to millimetres Feet to metres
Multiply by
2540 03048
To convert
Millimetres to inches Metres to feet
vIultiply by
003937 3281
Area Square inches to square millimetres 6452 Square millimetres to square inches 000155 Square feet to square metres 00929 Square metres to square feet 10764
Volume Cubic feet to cubic metres Cubic feet to litres Gallons (UK) to litres
002832 2831 4546
Cubic metres to cubic feet Litres to cubic feet Litres to gallons (UK)
35315 00353
022
Mass Ounces to grams Pounds to kiJograms Tons to tonnes
2835 04536
1016
Grams to ounces Kilograms to pounds Tonnes to tons
003527 2205
09842
Volume flow Cubic feet per minute to cubic Cubic metres per second to cubic
metres per second 0000472 feet per minute 2119 Cubic feet per mIDute to litres Litres per second to cubic feet
per second 04719 per minute 2119
Motion Feet per minute to metres per second 000508 Metres per second to feet per minute 197
Pressure Inches water gauge to millibars 2491 Inches wateJ- gauge to pascals (Pa) 2491 I Pa = I ewton per square metre = 10-2 millibars
60
Heating and Ventilating Contractors Association Esca House 34 Palace Court London W2 4JG
Tel 020 7313 4900
e-mail contact Itvcaorguk web site wwwhvcaorguk
Fax 020 7727 9268
DW154 SJecijicafion for Plastics Ductwork
ig 116 Permitted leakage at various pressures
Leakage in litres per second per square metre duct surface area
Vgt
o ltgt 0 ltgt N
ltgt Cgt
0 0 cc
0 0
~
g =
g ~
c 0
J
ltgt 0 I
~ ] tn
ltgt ltgt
In ol
~ 0 ~ 8 ~
~
c ltgt ltgt
~ CJ
~ ~ ~ ~ 8
0shyij
~ ~ ~ t
ltgt ltgt 00
l
~
~ Q
c C
~ rshy
e ltgt
I 1
I Cgt ltgtv
c Co ~
~~ ~ 10
I
0 Cgt
fJshyq 410 ) 1 ltgt
ltgt N
~ shy ltgt ltgt
~ I 1
c
52
DW154 Specificatio for Plastics Ductwork
Example of a completed test sheet Test No
General
Name of job N~ jC43Pt(r2lef Building Repound ~(~~0
Part 1 - Physical details
a Section of duct work to be tested ~(diffPIfff~el1f3rd Floor
b Drawing Number g91~~ c ssure aSSJ L atlOn V~Jl~IRfYgtg~~lPre Cl T Class C
d Test static pressure -(9 raErq~ ~~~~-~~J~~~ ~~ ~~~~ll
Leakaoe factor 9~-tre3$ecMz I OM REFTOTABLE 13)e b bullbullbullbullbullbullbull
f Surface area of duct under test Q~tJJItetre$ CPROMCALCU TIO BELOW)bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull ampampamp bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull
g ]Vlaxi mum permitted leakage -~ (~i~~0 ~~r~~ ~~~l-~-11~ ~~~Q
Part 2 - Test particulars
a Duct static pressure reading 9QFt~q~ ~ middot~~~1 ~~
b Manufacturer and type of liow measuring d vice (-~~~cJ~Y-9Q7EYg c Range of measurement of now measuring device QtP)OQ~(e~~~0I~~~~1~I~ ~~~~~~W~
d Reading of flm measurin o device pmiddot IFROM RIO)ftscag ~
I (DERlVED [ROM CHART SUPPUED WITH RIG US 0 ud)1e Interpreted air flow leakage rate ~(~~~f~~~ (~l~~~~~~~~~~~~~~~~~I
f Duration ~~~~~norn~allY l~ lnil1Ut~~d~~~ it1~ W~ Date of test ~(lITled ut by Wltll s ed by ~ ~
(~lJ MIJLrr) (Si~rrfltJUYJ
Printed Name 1~g0f~ Printed Name ~~Y~9~ and Company 7jl~~~~~( UJd CompanY AB COII$Itallt8
Width and depth or diameter
Periphery ength Area
millimetreS millimetres metre qL1are metre
800 x 750 3100 1755 5440
600 x 650 2500 557 1193
300 x 300 1200 120 144
305 din 958 700 670
250 dia 785 450 353
TOTAL 8000
53
DW154 Specijilarion for Plastics Ductwork
pA XB
Guida ce No es For he ransport Handling and
Storage of uctwork
avoid damage to adjacent duct panels In somc ca es particularly on con acts calling f r repetitive sizes the use of timber jigs and spacers may be justified Where reduced bulk and greater protection are major factor such as consignments for export transporting ductwork in L shape sections may justify the increa ed ite as embly co ts
It is recommended that before a contract is finalised that consideration is given to the subject of site acces material handling and storage as tbcy havgt a strong influence on the cost efficiency of the overall activity of ductwOlk installation
B3 Handling To minilnise th risk of damage duct sections should be clearly identified and deliveries to site should be closely linked to the installation programme so as to avoid accumulation of
B1 Storage and Handling of Ra Material Material should be stored in suitably designed racking out of direct unJight Where possible the e racks should be metal to earth Edges of cut she t may be harp and protective gloves are advised Wearing teel toe-capped boots is recommended Most pIa tic sheet is manufactured with smootb mfaces andor is suppLied with protective coating Care must be taken to prevent accidental lippag of stacked materials Beiuoshy good electrical insulators the movement of stock unless earthed will allow the build up of stati All stock shapes are chemically stable at normal temperature Whil t some raw materials used in their manufacture may themselves pre ent a toxic hazard once incorporated into the lOck bape they no long r constitute such a hazard and no dermatitic bazard are known nor are any
unfiJied ductwork and minimise double handling It is important to recognise that ductwork panels joint and corners arc susceptible to damage and care must be taken wheu band ling such material through a site During handling individual item of duct work may be liable to light cross sectional deformation until thev become an integral pan of a completed ductwork system Whilst this may temporarily detract from its intended appearance thi deformation will not have any detrimental effect on the functionality of the finally a semblecl system Installation of duct work and asociated plant items ill illevitably involve manual handUng The responsibi Iiry of employers and employees to a ses the risk of personal injury during mallual handling operations is et out in the HS E publication L23 Guidance on Manual Handling Regulations 1992
environmental problems expected 84 Site storage
B2 fransport Large capacity vehicles with high-sided open or closed-top bodies are tlle mo t suitable for the transport of dllctwork Careful consideration should be given to the
Adequate floor space IDust be provided within tbe building for the site storage of ductvork Such storage shalt make due allowance for thc stOf(ne of ductwork in stacks such that access ~ egt
between them is of sufficient width to pennil the removal of item without interference to
unloading of transport on sit a not all siJes b n fit from the material handlino- and access facilities that exi [ in a manufacturing workshop such as crane- fork-lifts or loading bay Site handJiog facilities along with
adjoining sta ks Ductvork components should be positioned so a to avoid crushing Ductwork of small panel size may be stored horizontally however care should be exercised to ensure that tack sizes are limited 10 within
ehicular acce s restrictions may itilluence the type and ize of transport to be uWised
engtlls of ductwork should be positioned 0
the tmctural strength of the duct sections to prevent distortion of the lower sections within the stack
as to avoid crushing Lengths Witll projections such as branches and bends i1anges girths damper quadrauL should be loaded so as to
54
DW154 S1tciic(ltioll for Plastics Ductwork
85 Internal cleanliness of new ductwork The site storage of ductwork introduces the important cODsideration of maintaining the internal cleanliness of the ductwork R feren e should be made to HVCA documentshybull DWffM2 Guide to Good Practice - internal
Cleanliness of New Ductwork Installations If the above conditioDs can not be satisfied consideration should be given by tJle designer to amending the specification to include for Po t Installation Cleaning as covered by tJ1C HVCA documentshybull TRJ17 Guide to Good Practic - Cleanliness
of Ventilation Systems
APPE DIXC
Fi e Retardant inishes C1 Improvement in the fire retardancy of plastic
ducts can be achieved to varying degrees and is wholly dependent llPOll the surface coating laminating resin selected and construction specification adopted In some instances smoke emission is coILSidered equaUy with other speci fication requirernen ts of the materials resistance to ignition and bumjng It is therefore important for design rs to establ ish the clients and officers detailed requirements and not rely on a tbird party interpretation of fire resisting or fire retardant Where possible the specification should refer dir etly to compliance with a British or European Standard identifying the specific sections applicable There are various types of resin and mat rcLnforcements that can achieve a Class 1 surface spread of flame ratin o when tested according to BS476 Part 7 (1987) This test puts materials illto Class I - 4 in descending order of perfoDllance according to the rat and extent of flame spread over their surfac under standard beating conditions Materials should also be tested for flre propagarion to BS476 Part 6 (1989) Tbi tesr measures the amount and rate of heat evolved by the material when subjected to standard heating
conditions Test results are given as an index of Perfonnance (i) whicb is based on three sub indices (iJ (i1) (h) The higher the value of the Index of Performance (i) the greater is the material s contribution to fire growth The higher the value of the sub-index 0) rhe greater the ease of ignition aod flame spread The highest product performance classification as defined in Approved Document B of the Building Regulations is Class O This is acLlieved if a material surface of a composite ploduct i~ either a) composed throughout of materials of
limited combustibility or b) a Class I material which has a tlre
propagation index (i) of not more than 12 and sub-index (i l ) of nor more than 6
01 J Class 0 is not a cla$sif1cation identified in any British Standard test
There are resin system reported to be classified to Class O when tested to BS476 Pcl1S 6 and 7 however designers need to ensure that such sysrems can be applied to their proposed design In propriety resinmat system available the fabrication techniques and COITect application are critical to the integrity of the reinforcing and clas ificatiol1 For example in some systems the u e of a non-fire retardant gelcont on a fire retardant substrate would reduce the classification For further information see HVCA publication DW144 Appendix D
55
DW154 SplCijiClIliol1 for Plastics Ductwork
x Guidance otes For nspectmiddoton Servicing a d
Clean-ng Access Openings
D1 GE ERAL This appendix highlight in ummary fOI111
the acce considerations that hould be made by the design r iD terms of inspection servicing and cleaning Having considered the seop and the design of the dUCI work system relative to the guidelines outlined below the designer should clearly indicate which levels of acces should be incorporated into the manufacture of a new duct work system (See Table 14 and Note I b low it
D2 DESIGN CONSIDERATIONS
D21 In ptction and servicing requireshyments are set out in Section 15 of Lhis specification
D22 Cleaning requirements are set out in the HVCA pubUcation TRl7 Guide to Good Practice Clean Lines of Ventilation Systems and the guide tates The precise location ize and
type of access would be dependent on the type of ductwork cleaning inspection and te ting metbods to b adopted Care protection and standards of cleanliness prior LO cOlllmisionin o
are set out in th AV A publication DWITM2 Guide to Good Practice Internal Cleanliness of New Ductwork Installations and th guide state Wh re specific limits of cleanliness are required ductwork sball be cleaned after installation by a spcialist cleaning contractor It will b in the interests of tht desioner botb financially and practically to cunsider employing a specialist c1eauing contractor at tbe
outset of a contract to internally clean newly installed ductwork prior to bandover This approach would reali e the following benefit shyi) Tb actual numb r of cleaning
access panels could be detennined to suit the method of cleaning to be adopted (This may be 1 s than the maximum requiremen listed under Lev 13 of Table 14)
ii) Clear directions could b given to the ductwork contractor as to tJle size and location of cleaning access panels that are required to be fitted during the mauushyfaclunng pro s
iii) The specialist cleaning operation prior to commi ioning vould enable the cleaning contractor to verify the practical acee requirement for the future cleaning operation associated -vitb a regular maintenance programme
iv) A specialist cleaning operation prior to commissioning would allow the designer to omit from the speeilicatiolJ the DWrrM2 requirem nt for factory sealing protection wipe downs and capping-off
v) Specialist Ieall ill 0 to the measurable standard defin d in TR17 will allow an objective definition of cleanline to be achieved
Car ful consideration must be gIven by the designer to the practl aJ problems associated witb the manufacture and fitting of suitably si Led access panel on small cross section duct and on the circular faces of rouod and flat oval ducts in particular
D23 Special con ideration must be given by the de igner to the practical problems associated with gaining personnel access to heavily congested ceiling areas and multi-la red du twork systems This approach would avoid
56
DW154 Spfciication for Plastics Ductwork
the possibility of access panels being D3 ACCESS 0 IN-LINE EQUIPMENT incorporated into a ductwork system at the This appendix unly covers acc il1spection manufacturing stage that were later found in through the ductwork body adjacent to an item practice to be inaccessible for either ervicing of in-line equipment and not openings in the or cleaning activities equipment itself
able 14 Acce requirements for inspection servicing and cleaning
HVCA PUBLICATIO REFE NeE (uidtgt 10 Gund Prartict
Adjace t OW144 Cleanliness orVcnlillltio S~lcr~ fRjJ7
in-line LeyeJ 1 Level 2 Level 3 ite sequipment pcdionSen lcin~ Section d C1eaniJl( SUn(O)lnspc lion Palle ltk~m_n
2011 (minimum OiL Jubje-ct to duct ~zel (ft~ -Panels
Control Da pcrs One (inspection) 203 One 300 mm x 200 mm Both sid Fire Dampers One (sCTjdJl~) 20211 One 300 0101 x 200 mm One side HeatingCooling Coils One (inspedion) 20213 One 300 mm x 200 mm (lIpstream) Both sides Attenuators (rectangular) None required One 300 mm x 200 mm (downstream) Both sides Attenuators (circular) one retluired One 300 mm x 200 mm (downstream) One side Filter Sections One (inspection) 20212 one required Uoth sides Air Turn Vanes None requjred None required Both sides Changes of Direction None required one required One side In-Duct FansDevices One (inspection) 20213 None required Both sides l
1 In the absence of any indication by the designer only Level ) access will be jncorporated into a new ductwork system
2 Tbe panel izes associated with Lev lis I and 3 acee s ar e middottablished by reference to Section 20 of DW144 and Section 2 ofTRll7 respectively
57
DW154 Speclfifatio for Plastics Ductwork
pA XE
B-bliography Included in this Bibliography are technical pUblications which may be of interest (0 ductwork designers fabricators and erectors and to tho e in the heating ventilatlng air conditioning industries generally nquiric should be made of the relevant organisation at the address quoted Since its publication other addresse contained within 0V154 mav have changed and some pubJicalions may have been superseded
HEATING AND VENTILATING CONTRACTORS ASSOCIATION
4 Palace Court London W2 4JG Telephone 020-7229 2488 Fax 020-7727 9268
Orders fo FlY A Publications Old Matlsion House Eamont Bridge Penrith Cumbria CA 10 2BX (Telephone 01768 864771 Fax 01768 86718) Email hvcapoblicationshvwelfarecouk DWn 44 pe ilicatiun for sheet mctal duclwork (Iow- mediulllshy
and high-pressure) 1998) DWIl4 A practical guide to dUGI ork I akage te ting
(revised 2000) DWII54 Specification for plastic~ duct rk DW171 Guide to good Practice for kitchen venlibtion system DW191 Guide to good pracuce glass fibre ductwoJk DwrrMI Acceptance cheme for new products - Redangolar cro
joint classification Guide to good pra tice - Internal cleanliness of new ductwork installations Guide to good practice for the design for the Installation of lire and smoke uampers
J 1Other puhlications
HampV safely guide 5th edition JS2 Tool box talks JS5 Weldlng Safety booklet JSI9 afety facts bo klet Fact sheets 1-24 2nd edition JS2J COSHH manual volume 1 Advice on compliance with the
regulations 1521A CO I-rH manual volume 2 Asses mcnt h ets JS23 Ri k management manual TR3 BrazinltT and bronze welding of copper pipework cUld sheet
(I 976) TR5 Welding of carbon steel pipework (1980)
TR6 Guide to Good Practice for Site Pre sure Testing of Pipework (19 0) Guide to good practice cleanliness of ventilation Ylem
CHARTERED IN TITUTlO OF BUILDING SERVICES E G EERS Delta House 222 Balham High Road London SW12 9BS rTelephone 020-8675 5211 Fax 020-8675 5449) CIBSE Guide Volume A Design Data Volume B In tallatiol1 and quipment Data Volume C Reference Data
CommlssioniJIg Codes These Codes eover the preliminary checkS eUing to work and regulation of vanous catcgories 0 plan The Codes give a guide to design implications Series A Air Distnbution Systems Series B Boiler Plant
ri s C Automatic Conlrol ystems Cr1es R Refrigerating Sy terns
Sene iN Water Distribution Systems
Technkal Memonllda TM 4 Design Notes for the Middle East TM bull Design otes for Ductwork TM 13 Minimi iog lhc Risk of egiounaires Disease
Research Reports RROI95 Ventilation system hygiene - A review of published
infomlatioo on lhe occurrence and ffects of Olltamination Rl~02J95 Air-to-air heal rec v ry RR0395 rnfluen e of HV C on smoke detectors
ATlONAL ENI [ERING SPECIFICATION LfMITED Southgatc hamber 3739 Southgate Street Winchester S023 9EH (Telephone 01962 842058 Fax 01962 R(8982) BUfLDING S RVICES RESEARCH AND [ ORMATION ASSOCIATIO Old Bracknell Lane West Bracknell Berkshire RG 12 4AH (Telephone Brackl1eU (01344) 426511 Fax 01344 487 -7 )
Application Guides AGln4 De tglJing Vana~le Volume middotylans for KOOnl
iir Movement AG1I91 Commissioning of V Sylcms in Buildings 11 6194 Fire Dampers
B) 94 cntiJalion or KitcneTls
AG389 The Commls ionin of Air Systems In Buildmgs AH2192 Commissioning of Bern - A ~ode of Practice TN2417 I Fire Dampec il) Ventilating Ducl
BEATING VENTILATING A AIR CONDITION G MA UFACTURERS ASSOCIATIO (HEVAC) HEVAC Henley Road Medmenham Marlow Buck SU 2ER (Telephone 01491 578674 ox 01491 575024 Emoimiddot infofetacouk)
Publicatjons Air Diffusion Guide Guide to Air Handling Unit Leakage Testing Guide to Good Practice Air Handling Unit Real Room Acoustic ~ st Procedure Specification for the ertiiicatioll ofAir Filters Method of Test for Water Rejection PerfOnTlatce of Louvrcs Subjected 1(1
Simulated Rainfall Test Procedure for Acoustic Loo cs Specification 10 Floor GrilJes - Types Performan e and Method ofTest Specification for the Determination of the Collection Efficiency of SilJ1d
Trap Louvre Domestic Mechwlical Vclltllalion Systems with Heal Recovery Fan Application Guid
~an and Ouctwork Installation Guide Guide to Fan Noise and Vibration
pecification of Requirements for JallJral Smoke and Heal Exhausl Ventilators
pecification for Powered Smoke and Heat Exhaust Ventilators
Specification of Requirements for Smoke Curtains Design Gujue of Smoke Ventilation for Single Storey Lodustrilll Building~
Including those with Mezzanine Floor and IIi Racked Storage Warehou es - Issue 3
Guidance for the Design of Smoke entilation YSlem for Covered and Undergrollnd Car Parks - lssue 1
Application of SOloke Control Equipment and Syst m Guid to Good Practice - Isue J
58
DW154 Sp(C~tiifitiol for Plastics Ductwork
BRITISH STANDARDS INSTIT TION Sales Department 101 P ntooviLle Road London NI 9ND (felephone 020-78 1 78801)
CP 413 1973 Ducts for building ervices
SS 476 Fire tes on building matenals and lruc(ure
Part 4 19 4 Non-combustibility lest or materials
Part 6 I Fire propagation lest for materials
Part 7 1993 Surface spread of tlarnJ tesls for materia
Part 20 1987 Fir resistance of elements of construction
Part 21 1987 Fire r sistlUlce of loadbeanng elements of construction
Part 22 1987 Fhe istallceofllon-loadbearing elemcllts ofconsttuclion Part 23 1987 Contribution of componcnts to the fire resistance 0 a
structure
Part 24t987 Fire resi lance of wl1lilation ductl
SS 5588 nan 919 0 Fire Precautions III thc desIgn and OOSlnJ lion of buildings
S 729 1971 Hot dip galvanized oatiugs (or irOIl aod stcel articles
BS 1449 Steel plate sheet and Irip
Pan 11991 Carbon steel plate heel and strip Part 2 1983 Stainless steel plate sheer and strip
and
B middotENJOI49-2 996 BSEN 10149- 1991)
BSEN 10131 1992
BSEN22063 Sprayed metal coarings 1994 Protection of iron and steel by aluminium and zinc against
atmospheric cOlosion Irotectiotl of iron and ste I against corro ion and oxishydation at elevared temperatures
BS 353 1981 Glossary of lerms relnting to thermal insulation
BS ISO 1479 Self-tapplngscrewsandmetallicdri c crew
B -lSO 7049
1994
B 4800 1989 Painl colour for building purposes B 4848 l0 rolled structural steel sections
Part4 1972 Equal and unequal angles BS 5422 1990 Specification for the use of therm illuating matcriulS
SS 5720 1979 ode of practice for mechanical veutilating and air C 11shy
dirionin bull in building
l3S PR 12814-1 Bend resting for plasric welds
SS PR 12814-2 Tensile testing for plastic welds
SS PR 13067 Appro altesting for plastic welds
BS PR EN I 100-] Vi ual in pection ofplaslic welds
SHEET METAL AND AIR CONDITIONING CONTR-CTORS NATIONAL ASSOCIATION INC (SMACNA) Headquarters 420 I Lafayeue Center Drive Chanlilly Virginia 2051-1209
Mailing Address pa Box 221230 Cbantilly Virginilt120 153-1230
Telephone (703) 803-2980 Fax (703) 803-3732
Accepted IJJdustry Pl3Gtice for Industrial Duct Constnlelion 197 ) i-rchitecmral Sheet kwl Manual ([993)
Comractors Guide lor Modification 10 ooslruerion Colllraets 1993 Ducted Eleclric Heat Guide for ir Handling Ssrerns (1994)
En~rgy ollservatioD Guidelines (1984) Energy Recovery Equipment yslClllS (199l
Fibrou GIns Duct onS1ntClion Standards (1992)
Fire Smoke amp Radiation Damper In tall Guide for HVA Syst ms (1992) Guide t leel Stack 1(95)
HVA Air Duct Leakage Test Manual (19 ) HVA COlllmissioning lvlanual (1994)
H A Duct Construction Standards-Metal amp Flexible (1995) Addendum 01 (Nov 1997)
HVA Duct Systems Inspection Guide (1989)
HVA ySlems-Application (1986) nVAC ByternS-DLlct D ign (1990)
HVi Systems-Testing Adjusting amp Balancing (1993)
indoor Air Quality Manual (1993) tcheu quipment Fabrication Guidelmes (1990)
Managers Guide for elding (1993)
Rectangular Industrial Duct Cons1TUction Standards (19 0) Round Industrial Duct oustmction Standards (1977)
Sei mic Restraint Manual (1991) (wl Appendix E 1993) SMACNA Ma le Index ()fTechnical Publications (1995) Tbennoplnstic Duct CPY ) Construction Manual 1994)
DEPARTME OF THE ENVIRO MENT (Publications Centre) H Stationery Oflice 5 Nine Elms Lane London SWS 5DR
MampEJ 011972 Electrical in tallat1011 in buildings ( ew Editiou)
IampE 0319 Healing hot and cold wat r steam and gas losla1lations for buildings
M amp - No4 1970 Central heating and hot and cold ~ ateT in tallations for
dwelling
M amp ENo100 1971 Mechanical ventilation for building~
ASSOCIATION FOR SPECIALIST FIRE PROTECTlO As ociation House 235 Ash Road AJdershot Hampshire GUl2 4DD
Telephone OJ25221322 Fax 0 J252 333901
lublicalioos Fire Ratcd and moke Outlet Ducrwork An Industry Guide t Design and InSlalla lioll
HEALTH AND SAFETY EXEC TIVE Rose Court 2 Southwark Bridge London SEl 9HS Telephone 020-7717 6000
TWJ THE WELD G TlTUTE Abington Hall Abington Cambridge CB16AL Telepbone 0 J223 89162
Publication DatJ Oil w~ldll1g of lhermopla lics
59
DW154 wciiwlioll for Plastics Ductwork
A -=--DIX
Factors
Specific gravity shy pp = 091 approx UPVC = 14 approx
Some miscellaneous conversion factors
To convert
Length Inches to millimetres Feet to metres
Multiply by
2540 03048
To convert
Millimetres to inches Metres to feet
vIultiply by
003937 3281
Area Square inches to square millimetres 6452 Square millimetres to square inches 000155 Square feet to square metres 00929 Square metres to square feet 10764
Volume Cubic feet to cubic metres Cubic feet to litres Gallons (UK) to litres
002832 2831 4546
Cubic metres to cubic feet Litres to cubic feet Litres to gallons (UK)
35315 00353
022
Mass Ounces to grams Pounds to kiJograms Tons to tonnes
2835 04536
1016
Grams to ounces Kilograms to pounds Tonnes to tons
003527 2205
09842
Volume flow Cubic feet per minute to cubic Cubic metres per second to cubic
metres per second 0000472 feet per minute 2119 Cubic feet per mIDute to litres Litres per second to cubic feet
per second 04719 per minute 2119
Motion Feet per minute to metres per second 000508 Metres per second to feet per minute 197
Pressure Inches water gauge to millibars 2491 Inches wateJ- gauge to pascals (Pa) 2491 I Pa = I ewton per square metre = 10-2 millibars
60
Heating and Ventilating Contractors Association Esca House 34 Palace Court London W2 4JG
Tel 020 7313 4900
e-mail contact Itvcaorguk web site wwwhvcaorguk
Fax 020 7727 9268
DW154 Specificatio for Plastics Ductwork
Example of a completed test sheet Test No
General
Name of job N~ jC43Pt(r2lef Building Repound ~(~~0
Part 1 - Physical details
a Section of duct work to be tested ~(diffPIfff~el1f3rd Floor
b Drawing Number g91~~ c ssure aSSJ L atlOn V~Jl~IRfYgtg~~lPre Cl T Class C
d Test static pressure -(9 raErq~ ~~~~-~~J~~~ ~~ ~~~~ll
Leakaoe factor 9~-tre3$ecMz I OM REFTOTABLE 13)e b bullbullbullbullbullbullbull
f Surface area of duct under test Q~tJJItetre$ CPROMCALCU TIO BELOW)bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull ampampamp bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull
g ]Vlaxi mum permitted leakage -~ (~i~~0 ~~r~~ ~~~l-~-11~ ~~~Q
Part 2 - Test particulars
a Duct static pressure reading 9QFt~q~ ~ middot~~~1 ~~
b Manufacturer and type of liow measuring d vice (-~~~cJ~Y-9Q7EYg c Range of measurement of now measuring device QtP)OQ~(e~~~0I~~~~1~I~ ~~~~~~W~
d Reading of flm measurin o device pmiddot IFROM RIO)ftscag ~
I (DERlVED [ROM CHART SUPPUED WITH RIG US 0 ud)1e Interpreted air flow leakage rate ~(~~~f~~~ (~l~~~~~~~~~~~~~~~~~I
f Duration ~~~~~norn~allY l~ lnil1Ut~~d~~~ it1~ W~ Date of test ~(lITled ut by Wltll s ed by ~ ~
(~lJ MIJLrr) (Si~rrfltJUYJ
Printed Name 1~g0f~ Printed Name ~~Y~9~ and Company 7jl~~~~~( UJd CompanY AB COII$Itallt8
Width and depth or diameter
Periphery ength Area
millimetreS millimetres metre qL1are metre
800 x 750 3100 1755 5440
600 x 650 2500 557 1193
300 x 300 1200 120 144
305 din 958 700 670
250 dia 785 450 353
TOTAL 8000
53
DW154 Specijilarion for Plastics Ductwork
pA XB
Guida ce No es For he ransport Handling and
Storage of uctwork
avoid damage to adjacent duct panels In somc ca es particularly on con acts calling f r repetitive sizes the use of timber jigs and spacers may be justified Where reduced bulk and greater protection are major factor such as consignments for export transporting ductwork in L shape sections may justify the increa ed ite as embly co ts
It is recommended that before a contract is finalised that consideration is given to the subject of site acces material handling and storage as tbcy havgt a strong influence on the cost efficiency of the overall activity of ductwOlk installation
B3 Handling To minilnise th risk of damage duct sections should be clearly identified and deliveries to site should be closely linked to the installation programme so as to avoid accumulation of
B1 Storage and Handling of Ra Material Material should be stored in suitably designed racking out of direct unJight Where possible the e racks should be metal to earth Edges of cut she t may be harp and protective gloves are advised Wearing teel toe-capped boots is recommended Most pIa tic sheet is manufactured with smootb mfaces andor is suppLied with protective coating Care must be taken to prevent accidental lippag of stacked materials Beiuoshy good electrical insulators the movement of stock unless earthed will allow the build up of stati All stock shapes are chemically stable at normal temperature Whil t some raw materials used in their manufacture may themselves pre ent a toxic hazard once incorporated into the lOck bape they no long r constitute such a hazard and no dermatitic bazard are known nor are any
unfiJied ductwork and minimise double handling It is important to recognise that ductwork panels joint and corners arc susceptible to damage and care must be taken wheu band ling such material through a site During handling individual item of duct work may be liable to light cross sectional deformation until thev become an integral pan of a completed ductwork system Whilst this may temporarily detract from its intended appearance thi deformation will not have any detrimental effect on the functionality of the finally a semblecl system Installation of duct work and asociated plant items ill illevitably involve manual handUng The responsibi Iiry of employers and employees to a ses the risk of personal injury during mallual handling operations is et out in the HS E publication L23 Guidance on Manual Handling Regulations 1992
environmental problems expected 84 Site storage
B2 fransport Large capacity vehicles with high-sided open or closed-top bodies are tlle mo t suitable for the transport of dllctwork Careful consideration should be given to the
Adequate floor space IDust be provided within tbe building for the site storage of ductvork Such storage shalt make due allowance for thc stOf(ne of ductwork in stacks such that access ~ egt
between them is of sufficient width to pennil the removal of item without interference to
unloading of transport on sit a not all siJes b n fit from the material handlino- and access facilities that exi [ in a manufacturing workshop such as crane- fork-lifts or loading bay Site handJiog facilities along with
adjoining sta ks Ductvork components should be positioned so a to avoid crushing Ductwork of small panel size may be stored horizontally however care should be exercised to ensure that tack sizes are limited 10 within
ehicular acce s restrictions may itilluence the type and ize of transport to be uWised
engtlls of ductwork should be positioned 0
the tmctural strength of the duct sections to prevent distortion of the lower sections within the stack
as to avoid crushing Lengths Witll projections such as branches and bends i1anges girths damper quadrauL should be loaded so as to
54
DW154 S1tciic(ltioll for Plastics Ductwork
85 Internal cleanliness of new ductwork The site storage of ductwork introduces the important cODsideration of maintaining the internal cleanliness of the ductwork R feren e should be made to HVCA documentshybull DWffM2 Guide to Good Practice - internal
Cleanliness of New Ductwork Installations If the above conditioDs can not be satisfied consideration should be given by tJle designer to amending the specification to include for Po t Installation Cleaning as covered by tJ1C HVCA documentshybull TRJ17 Guide to Good Practic - Cleanliness
of Ventilation Systems
APPE DIXC
Fi e Retardant inishes C1 Improvement in the fire retardancy of plastic
ducts can be achieved to varying degrees and is wholly dependent llPOll the surface coating laminating resin selected and construction specification adopted In some instances smoke emission is coILSidered equaUy with other speci fication requirernen ts of the materials resistance to ignition and bumjng It is therefore important for design rs to establ ish the clients and officers detailed requirements and not rely on a tbird party interpretation of fire resisting or fire retardant Where possible the specification should refer dir etly to compliance with a British or European Standard identifying the specific sections applicable There are various types of resin and mat rcLnforcements that can achieve a Class 1 surface spread of flame ratin o when tested according to BS476 Part 7 (1987) This test puts materials illto Class I - 4 in descending order of perfoDllance according to the rat and extent of flame spread over their surfac under standard beating conditions Materials should also be tested for flre propagarion to BS476 Part 6 (1989) Tbi tesr measures the amount and rate of heat evolved by the material when subjected to standard heating
conditions Test results are given as an index of Perfonnance (i) whicb is based on three sub indices (iJ (i1) (h) The higher the value of the Index of Performance (i) the greater is the material s contribution to fire growth The higher the value of the sub-index 0) rhe greater the ease of ignition aod flame spread The highest product performance classification as defined in Approved Document B of the Building Regulations is Class O This is acLlieved if a material surface of a composite ploduct i~ either a) composed throughout of materials of
limited combustibility or b) a Class I material which has a tlre
propagation index (i) of not more than 12 and sub-index (i l ) of nor more than 6
01 J Class 0 is not a cla$sif1cation identified in any British Standard test
There are resin system reported to be classified to Class O when tested to BS476 Pcl1S 6 and 7 however designers need to ensure that such sysrems can be applied to their proposed design In propriety resinmat system available the fabrication techniques and COITect application are critical to the integrity of the reinforcing and clas ificatiol1 For example in some systems the u e of a non-fire retardant gelcont on a fire retardant substrate would reduce the classification For further information see HVCA publication DW144 Appendix D
55
DW154 SplCijiClIliol1 for Plastics Ductwork
x Guidance otes For nspectmiddoton Servicing a d
Clean-ng Access Openings
D1 GE ERAL This appendix highlight in ummary fOI111
the acce considerations that hould be made by the design r iD terms of inspection servicing and cleaning Having considered the seop and the design of the dUCI work system relative to the guidelines outlined below the designer should clearly indicate which levels of acces should be incorporated into the manufacture of a new duct work system (See Table 14 and Note I b low it
D2 DESIGN CONSIDERATIONS
D21 In ptction and servicing requireshyments are set out in Section 15 of Lhis specification
D22 Cleaning requirements are set out in the HVCA pubUcation TRl7 Guide to Good Practice Clean Lines of Ventilation Systems and the guide tates The precise location ize and
type of access would be dependent on the type of ductwork cleaning inspection and te ting metbods to b adopted Care protection and standards of cleanliness prior LO cOlllmisionin o
are set out in th AV A publication DWITM2 Guide to Good Practice Internal Cleanliness of New Ductwork Installations and th guide state Wh re specific limits of cleanliness are required ductwork sball be cleaned after installation by a spcialist cleaning contractor It will b in the interests of tht desioner botb financially and practically to cunsider employing a specialist c1eauing contractor at tbe
outset of a contract to internally clean newly installed ductwork prior to bandover This approach would reali e the following benefit shyi) Tb actual numb r of cleaning
access panels could be detennined to suit the method of cleaning to be adopted (This may be 1 s than the maximum requiremen listed under Lev 13 of Table 14)
ii) Clear directions could b given to the ductwork contractor as to tJle size and location of cleaning access panels that are required to be fitted during the mauushyfaclunng pro s
iii) The specialist cleaning operation prior to commi ioning vould enable the cleaning contractor to verify the practical acee requirement for the future cleaning operation associated -vitb a regular maintenance programme
iv) A specialist cleaning operation prior to commissioning would allow the designer to omit from the speeilicatiolJ the DWrrM2 requirem nt for factory sealing protection wipe downs and capping-off
v) Specialist Ieall ill 0 to the measurable standard defin d in TR17 will allow an objective definition of cleanline to be achieved
Car ful consideration must be gIven by the designer to the practl aJ problems associated witb the manufacture and fitting of suitably si Led access panel on small cross section duct and on the circular faces of rouod and flat oval ducts in particular
D23 Special con ideration must be given by the de igner to the practical problems associated with gaining personnel access to heavily congested ceiling areas and multi-la red du twork systems This approach would avoid
56
DW154 Spfciication for Plastics Ductwork
the possibility of access panels being D3 ACCESS 0 IN-LINE EQUIPMENT incorporated into a ductwork system at the This appendix unly covers acc il1spection manufacturing stage that were later found in through the ductwork body adjacent to an item practice to be inaccessible for either ervicing of in-line equipment and not openings in the or cleaning activities equipment itself
able 14 Acce requirements for inspection servicing and cleaning
HVCA PUBLICATIO REFE NeE (uidtgt 10 Gund Prartict
Adjace t OW144 Cleanliness orVcnlillltio S~lcr~ fRjJ7
in-line LeyeJ 1 Level 2 Level 3 ite sequipment pcdionSen lcin~ Section d C1eaniJl( SUn(O)lnspc lion Palle ltk~m_n
2011 (minimum OiL Jubje-ct to duct ~zel (ft~ -Panels
Control Da pcrs One (inspection) 203 One 300 mm x 200 mm Both sid Fire Dampers One (sCTjdJl~) 20211 One 300 0101 x 200 mm One side HeatingCooling Coils One (inspedion) 20213 One 300 mm x 200 mm (lIpstream) Both sides Attenuators (rectangular) None required One 300 mm x 200 mm (downstream) Both sides Attenuators (circular) one retluired One 300 mm x 200 mm (downstream) One side Filter Sections One (inspection) 20212 one required Uoth sides Air Turn Vanes None requjred None required Both sides Changes of Direction None required one required One side In-Duct FansDevices One (inspection) 20213 None required Both sides l
1 In the absence of any indication by the designer only Level ) access will be jncorporated into a new ductwork system
2 Tbe panel izes associated with Lev lis I and 3 acee s ar e middottablished by reference to Section 20 of DW144 and Section 2 ofTRll7 respectively
57
DW154 Speclfifatio for Plastics Ductwork
pA XE
B-bliography Included in this Bibliography are technical pUblications which may be of interest (0 ductwork designers fabricators and erectors and to tho e in the heating ventilatlng air conditioning industries generally nquiric should be made of the relevant organisation at the address quoted Since its publication other addresse contained within 0V154 mav have changed and some pubJicalions may have been superseded
HEATING AND VENTILATING CONTRACTORS ASSOCIATION
4 Palace Court London W2 4JG Telephone 020-7229 2488 Fax 020-7727 9268
Orders fo FlY A Publications Old Matlsion House Eamont Bridge Penrith Cumbria CA 10 2BX (Telephone 01768 864771 Fax 01768 86718) Email hvcapoblicationshvwelfarecouk DWn 44 pe ilicatiun for sheet mctal duclwork (Iow- mediulllshy
and high-pressure) 1998) DWIl4 A practical guide to dUGI ork I akage te ting
(revised 2000) DWII54 Specification for plastic~ duct rk DW171 Guide to good Practice for kitchen venlibtion system DW191 Guide to good pracuce glass fibre ductwoJk DwrrMI Acceptance cheme for new products - Redangolar cro
joint classification Guide to good pra tice - Internal cleanliness of new ductwork installations Guide to good practice for the design for the Installation of lire and smoke uampers
J 1Other puhlications
HampV safely guide 5th edition JS2 Tool box talks JS5 Weldlng Safety booklet JSI9 afety facts bo klet Fact sheets 1-24 2nd edition JS2J COSHH manual volume 1 Advice on compliance with the
regulations 1521A CO I-rH manual volume 2 Asses mcnt h ets JS23 Ri k management manual TR3 BrazinltT and bronze welding of copper pipework cUld sheet
(I 976) TR5 Welding of carbon steel pipework (1980)
TR6 Guide to Good Practice for Site Pre sure Testing of Pipework (19 0) Guide to good practice cleanliness of ventilation Ylem
CHARTERED IN TITUTlO OF BUILDING SERVICES E G EERS Delta House 222 Balham High Road London SW12 9BS rTelephone 020-8675 5211 Fax 020-8675 5449) CIBSE Guide Volume A Design Data Volume B In tallatiol1 and quipment Data Volume C Reference Data
CommlssioniJIg Codes These Codes eover the preliminary checkS eUing to work and regulation of vanous catcgories 0 plan The Codes give a guide to design implications Series A Air Distnbution Systems Series B Boiler Plant
ri s C Automatic Conlrol ystems Cr1es R Refrigerating Sy terns
Sene iN Water Distribution Systems
Technkal Memonllda TM 4 Design Notes for the Middle East TM bull Design otes for Ductwork TM 13 Minimi iog lhc Risk of egiounaires Disease
Research Reports RROI95 Ventilation system hygiene - A review of published
infomlatioo on lhe occurrence and ffects of Olltamination Rl~02J95 Air-to-air heal rec v ry RR0395 rnfluen e of HV C on smoke detectors
ATlONAL ENI [ERING SPECIFICATION LfMITED Southgatc hamber 3739 Southgate Street Winchester S023 9EH (Telephone 01962 842058 Fax 01962 R(8982) BUfLDING S RVICES RESEARCH AND [ ORMATION ASSOCIATIO Old Bracknell Lane West Bracknell Berkshire RG 12 4AH (Telephone Brackl1eU (01344) 426511 Fax 01344 487 -7 )
Application Guides AGln4 De tglJing Vana~le Volume middotylans for KOOnl
iir Movement AG1I91 Commissioning of V Sylcms in Buildings 11 6194 Fire Dampers
B) 94 cntiJalion or KitcneTls
AG389 The Commls ionin of Air Systems In Buildmgs AH2192 Commissioning of Bern - A ~ode of Practice TN2417 I Fire Dampec il) Ventilating Ducl
BEATING VENTILATING A AIR CONDITION G MA UFACTURERS ASSOCIATIO (HEVAC) HEVAC Henley Road Medmenham Marlow Buck SU 2ER (Telephone 01491 578674 ox 01491 575024 Emoimiddot infofetacouk)
Publicatjons Air Diffusion Guide Guide to Air Handling Unit Leakage Testing Guide to Good Practice Air Handling Unit Real Room Acoustic ~ st Procedure Specification for the ertiiicatioll ofAir Filters Method of Test for Water Rejection PerfOnTlatce of Louvrcs Subjected 1(1
Simulated Rainfall Test Procedure for Acoustic Loo cs Specification 10 Floor GrilJes - Types Performan e and Method ofTest Specification for the Determination of the Collection Efficiency of SilJ1d
Trap Louvre Domestic Mechwlical Vclltllalion Systems with Heal Recovery Fan Application Guid
~an and Ouctwork Installation Guide Guide to Fan Noise and Vibration
pecification of Requirements for JallJral Smoke and Heal Exhausl Ventilators
pecification for Powered Smoke and Heat Exhaust Ventilators
Specification of Requirements for Smoke Curtains Design Gujue of Smoke Ventilation for Single Storey Lodustrilll Building~
Including those with Mezzanine Floor and IIi Racked Storage Warehou es - Issue 3
Guidance for the Design of Smoke entilation YSlem for Covered and Undergrollnd Car Parks - lssue 1
Application of SOloke Control Equipment and Syst m Guid to Good Practice - Isue J
58
DW154 Sp(C~tiifitiol for Plastics Ductwork
BRITISH STANDARDS INSTIT TION Sales Department 101 P ntooviLle Road London NI 9ND (felephone 020-78 1 78801)
CP 413 1973 Ducts for building ervices
SS 476 Fire tes on building matenals and lruc(ure
Part 4 19 4 Non-combustibility lest or materials
Part 6 I Fire propagation lest for materials
Part 7 1993 Surface spread of tlarnJ tesls for materia
Part 20 1987 Fir resistance of elements of construction
Part 21 1987 Fire r sistlUlce of loadbeanng elements of construction
Part 22 1987 Fhe istallceofllon-loadbearing elemcllts ofconsttuclion Part 23 1987 Contribution of componcnts to the fire resistance 0 a
structure
Part 24t987 Fire resi lance of wl1lilation ductl
SS 5588 nan 919 0 Fire Precautions III thc desIgn and OOSlnJ lion of buildings
S 729 1971 Hot dip galvanized oatiugs (or irOIl aod stcel articles
BS 1449 Steel plate sheet and Irip
Pan 11991 Carbon steel plate heel and strip Part 2 1983 Stainless steel plate sheer and strip
and
B middotENJOI49-2 996 BSEN 10149- 1991)
BSEN 10131 1992
BSEN22063 Sprayed metal coarings 1994 Protection of iron and steel by aluminium and zinc against
atmospheric cOlosion Irotectiotl of iron and ste I against corro ion and oxishydation at elevared temperatures
BS 353 1981 Glossary of lerms relnting to thermal insulation
BS ISO 1479 Self-tapplngscrewsandmetallicdri c crew
B -lSO 7049
1994
B 4800 1989 Painl colour for building purposes B 4848 l0 rolled structural steel sections
Part4 1972 Equal and unequal angles BS 5422 1990 Specification for the use of therm illuating matcriulS
SS 5720 1979 ode of practice for mechanical veutilating and air C 11shy
dirionin bull in building
l3S PR 12814-1 Bend resting for plasric welds
SS PR 12814-2 Tensile testing for plastic welds
SS PR 13067 Appro altesting for plastic welds
BS PR EN I 100-] Vi ual in pection ofplaslic welds
SHEET METAL AND AIR CONDITIONING CONTR-CTORS NATIONAL ASSOCIATION INC (SMACNA) Headquarters 420 I Lafayeue Center Drive Chanlilly Virginia 2051-1209
Mailing Address pa Box 221230 Cbantilly Virginilt120 153-1230
Telephone (703) 803-2980 Fax (703) 803-3732
Accepted IJJdustry Pl3Gtice for Industrial Duct Constnlelion 197 ) i-rchitecmral Sheet kwl Manual ([993)
Comractors Guide lor Modification 10 ooslruerion Colllraets 1993 Ducted Eleclric Heat Guide for ir Handling Ssrerns (1994)
En~rgy ollservatioD Guidelines (1984) Energy Recovery Equipment yslClllS (199l
Fibrou GIns Duct onS1ntClion Standards (1992)
Fire Smoke amp Radiation Damper In tall Guide for HVA Syst ms (1992) Guide t leel Stack 1(95)
HVA Air Duct Leakage Test Manual (19 ) HVA COlllmissioning lvlanual (1994)
H A Duct Construction Standards-Metal amp Flexible (1995) Addendum 01 (Nov 1997)
HVA Duct Systems Inspection Guide (1989)
HVA ySlems-Application (1986) nVAC ByternS-DLlct D ign (1990)
HVi Systems-Testing Adjusting amp Balancing (1993)
indoor Air Quality Manual (1993) tcheu quipment Fabrication Guidelmes (1990)
Managers Guide for elding (1993)
Rectangular Industrial Duct Cons1TUction Standards (19 0) Round Industrial Duct oustmction Standards (1977)
Sei mic Restraint Manual (1991) (wl Appendix E 1993) SMACNA Ma le Index ()fTechnical Publications (1995) Tbennoplnstic Duct CPY ) Construction Manual 1994)
DEPARTME OF THE ENVIRO MENT (Publications Centre) H Stationery Oflice 5 Nine Elms Lane London SWS 5DR
MampEJ 011972 Electrical in tallat1011 in buildings ( ew Editiou)
IampE 0319 Healing hot and cold wat r steam and gas losla1lations for buildings
M amp - No4 1970 Central heating and hot and cold ~ ateT in tallations for
dwelling
M amp ENo100 1971 Mechanical ventilation for building~
ASSOCIATION FOR SPECIALIST FIRE PROTECTlO As ociation House 235 Ash Road AJdershot Hampshire GUl2 4DD
Telephone OJ25221322 Fax 0 J252 333901
lublicalioos Fire Ratcd and moke Outlet Ducrwork An Industry Guide t Design and InSlalla lioll
HEALTH AND SAFETY EXEC TIVE Rose Court 2 Southwark Bridge London SEl 9HS Telephone 020-7717 6000
TWJ THE WELD G TlTUTE Abington Hall Abington Cambridge CB16AL Telepbone 0 J223 89162
Publication DatJ Oil w~ldll1g of lhermopla lics
59
DW154 wciiwlioll for Plastics Ductwork
A -=--DIX
Factors
Specific gravity shy pp = 091 approx UPVC = 14 approx
Some miscellaneous conversion factors
To convert
Length Inches to millimetres Feet to metres
Multiply by
2540 03048
To convert
Millimetres to inches Metres to feet
vIultiply by
003937 3281
Area Square inches to square millimetres 6452 Square millimetres to square inches 000155 Square feet to square metres 00929 Square metres to square feet 10764
Volume Cubic feet to cubic metres Cubic feet to litres Gallons (UK) to litres
002832 2831 4546
Cubic metres to cubic feet Litres to cubic feet Litres to gallons (UK)
35315 00353
022
Mass Ounces to grams Pounds to kiJograms Tons to tonnes
2835 04536
1016
Grams to ounces Kilograms to pounds Tonnes to tons
003527 2205
09842
Volume flow Cubic feet per minute to cubic Cubic metres per second to cubic
metres per second 0000472 feet per minute 2119 Cubic feet per mIDute to litres Litres per second to cubic feet
per second 04719 per minute 2119
Motion Feet per minute to metres per second 000508 Metres per second to feet per minute 197
Pressure Inches water gauge to millibars 2491 Inches wateJ- gauge to pascals (Pa) 2491 I Pa = I ewton per square metre = 10-2 millibars
60
Heating and Ventilating Contractors Association Esca House 34 Palace Court London W2 4JG
Tel 020 7313 4900
e-mail contact Itvcaorguk web site wwwhvcaorguk
Fax 020 7727 9268
DW154 Specijilarion for Plastics Ductwork
pA XB
Guida ce No es For he ransport Handling and
Storage of uctwork
avoid damage to adjacent duct panels In somc ca es particularly on con acts calling f r repetitive sizes the use of timber jigs and spacers may be justified Where reduced bulk and greater protection are major factor such as consignments for export transporting ductwork in L shape sections may justify the increa ed ite as embly co ts
It is recommended that before a contract is finalised that consideration is given to the subject of site acces material handling and storage as tbcy havgt a strong influence on the cost efficiency of the overall activity of ductwOlk installation
B3 Handling To minilnise th risk of damage duct sections should be clearly identified and deliveries to site should be closely linked to the installation programme so as to avoid accumulation of
B1 Storage and Handling of Ra Material Material should be stored in suitably designed racking out of direct unJight Where possible the e racks should be metal to earth Edges of cut she t may be harp and protective gloves are advised Wearing teel toe-capped boots is recommended Most pIa tic sheet is manufactured with smootb mfaces andor is suppLied with protective coating Care must be taken to prevent accidental lippag of stacked materials Beiuoshy good electrical insulators the movement of stock unless earthed will allow the build up of stati All stock shapes are chemically stable at normal temperature Whil t some raw materials used in their manufacture may themselves pre ent a toxic hazard once incorporated into the lOck bape they no long r constitute such a hazard and no dermatitic bazard are known nor are any
unfiJied ductwork and minimise double handling It is important to recognise that ductwork panels joint and corners arc susceptible to damage and care must be taken wheu band ling such material through a site During handling individual item of duct work may be liable to light cross sectional deformation until thev become an integral pan of a completed ductwork system Whilst this may temporarily detract from its intended appearance thi deformation will not have any detrimental effect on the functionality of the finally a semblecl system Installation of duct work and asociated plant items ill illevitably involve manual handUng The responsibi Iiry of employers and employees to a ses the risk of personal injury during mallual handling operations is et out in the HS E publication L23 Guidance on Manual Handling Regulations 1992
environmental problems expected 84 Site storage
B2 fransport Large capacity vehicles with high-sided open or closed-top bodies are tlle mo t suitable for the transport of dllctwork Careful consideration should be given to the
Adequate floor space IDust be provided within tbe building for the site storage of ductvork Such storage shalt make due allowance for thc stOf(ne of ductwork in stacks such that access ~ egt
between them is of sufficient width to pennil the removal of item without interference to
unloading of transport on sit a not all siJes b n fit from the material handlino- and access facilities that exi [ in a manufacturing workshop such as crane- fork-lifts or loading bay Site handJiog facilities along with
adjoining sta ks Ductvork components should be positioned so a to avoid crushing Ductwork of small panel size may be stored horizontally however care should be exercised to ensure that tack sizes are limited 10 within
ehicular acce s restrictions may itilluence the type and ize of transport to be uWised
engtlls of ductwork should be positioned 0
the tmctural strength of the duct sections to prevent distortion of the lower sections within the stack
as to avoid crushing Lengths Witll projections such as branches and bends i1anges girths damper quadrauL should be loaded so as to
54
DW154 S1tciic(ltioll for Plastics Ductwork
85 Internal cleanliness of new ductwork The site storage of ductwork introduces the important cODsideration of maintaining the internal cleanliness of the ductwork R feren e should be made to HVCA documentshybull DWffM2 Guide to Good Practice - internal
Cleanliness of New Ductwork Installations If the above conditioDs can not be satisfied consideration should be given by tJle designer to amending the specification to include for Po t Installation Cleaning as covered by tJ1C HVCA documentshybull TRJ17 Guide to Good Practic - Cleanliness
of Ventilation Systems
APPE DIXC
Fi e Retardant inishes C1 Improvement in the fire retardancy of plastic
ducts can be achieved to varying degrees and is wholly dependent llPOll the surface coating laminating resin selected and construction specification adopted In some instances smoke emission is coILSidered equaUy with other speci fication requirernen ts of the materials resistance to ignition and bumjng It is therefore important for design rs to establ ish the clients and officers detailed requirements and not rely on a tbird party interpretation of fire resisting or fire retardant Where possible the specification should refer dir etly to compliance with a British or European Standard identifying the specific sections applicable There are various types of resin and mat rcLnforcements that can achieve a Class 1 surface spread of flame ratin o when tested according to BS476 Part 7 (1987) This test puts materials illto Class I - 4 in descending order of perfoDllance according to the rat and extent of flame spread over their surfac under standard beating conditions Materials should also be tested for flre propagarion to BS476 Part 6 (1989) Tbi tesr measures the amount and rate of heat evolved by the material when subjected to standard heating
conditions Test results are given as an index of Perfonnance (i) whicb is based on three sub indices (iJ (i1) (h) The higher the value of the Index of Performance (i) the greater is the material s contribution to fire growth The higher the value of the sub-index 0) rhe greater the ease of ignition aod flame spread The highest product performance classification as defined in Approved Document B of the Building Regulations is Class O This is acLlieved if a material surface of a composite ploduct i~ either a) composed throughout of materials of
limited combustibility or b) a Class I material which has a tlre
propagation index (i) of not more than 12 and sub-index (i l ) of nor more than 6
01 J Class 0 is not a cla$sif1cation identified in any British Standard test
There are resin system reported to be classified to Class O when tested to BS476 Pcl1S 6 and 7 however designers need to ensure that such sysrems can be applied to their proposed design In propriety resinmat system available the fabrication techniques and COITect application are critical to the integrity of the reinforcing and clas ificatiol1 For example in some systems the u e of a non-fire retardant gelcont on a fire retardant substrate would reduce the classification For further information see HVCA publication DW144 Appendix D
55
DW154 SplCijiClIliol1 for Plastics Ductwork
x Guidance otes For nspectmiddoton Servicing a d
Clean-ng Access Openings
D1 GE ERAL This appendix highlight in ummary fOI111
the acce considerations that hould be made by the design r iD terms of inspection servicing and cleaning Having considered the seop and the design of the dUCI work system relative to the guidelines outlined below the designer should clearly indicate which levels of acces should be incorporated into the manufacture of a new duct work system (See Table 14 and Note I b low it
D2 DESIGN CONSIDERATIONS
D21 In ptction and servicing requireshyments are set out in Section 15 of Lhis specification
D22 Cleaning requirements are set out in the HVCA pubUcation TRl7 Guide to Good Practice Clean Lines of Ventilation Systems and the guide tates The precise location ize and
type of access would be dependent on the type of ductwork cleaning inspection and te ting metbods to b adopted Care protection and standards of cleanliness prior LO cOlllmisionin o
are set out in th AV A publication DWITM2 Guide to Good Practice Internal Cleanliness of New Ductwork Installations and th guide state Wh re specific limits of cleanliness are required ductwork sball be cleaned after installation by a spcialist cleaning contractor It will b in the interests of tht desioner botb financially and practically to cunsider employing a specialist c1eauing contractor at tbe
outset of a contract to internally clean newly installed ductwork prior to bandover This approach would reali e the following benefit shyi) Tb actual numb r of cleaning
access panels could be detennined to suit the method of cleaning to be adopted (This may be 1 s than the maximum requiremen listed under Lev 13 of Table 14)
ii) Clear directions could b given to the ductwork contractor as to tJle size and location of cleaning access panels that are required to be fitted during the mauushyfaclunng pro s
iii) The specialist cleaning operation prior to commi ioning vould enable the cleaning contractor to verify the practical acee requirement for the future cleaning operation associated -vitb a regular maintenance programme
iv) A specialist cleaning operation prior to commissioning would allow the designer to omit from the speeilicatiolJ the DWrrM2 requirem nt for factory sealing protection wipe downs and capping-off
v) Specialist Ieall ill 0 to the measurable standard defin d in TR17 will allow an objective definition of cleanline to be achieved
Car ful consideration must be gIven by the designer to the practl aJ problems associated witb the manufacture and fitting of suitably si Led access panel on small cross section duct and on the circular faces of rouod and flat oval ducts in particular
D23 Special con ideration must be given by the de igner to the practical problems associated with gaining personnel access to heavily congested ceiling areas and multi-la red du twork systems This approach would avoid
56
DW154 Spfciication for Plastics Ductwork
the possibility of access panels being D3 ACCESS 0 IN-LINE EQUIPMENT incorporated into a ductwork system at the This appendix unly covers acc il1spection manufacturing stage that were later found in through the ductwork body adjacent to an item practice to be inaccessible for either ervicing of in-line equipment and not openings in the or cleaning activities equipment itself
able 14 Acce requirements for inspection servicing and cleaning
HVCA PUBLICATIO REFE NeE (uidtgt 10 Gund Prartict
Adjace t OW144 Cleanliness orVcnlillltio S~lcr~ fRjJ7
in-line LeyeJ 1 Level 2 Level 3 ite sequipment pcdionSen lcin~ Section d C1eaniJl( SUn(O)lnspc lion Palle ltk~m_n
2011 (minimum OiL Jubje-ct to duct ~zel (ft~ -Panels
Control Da pcrs One (inspection) 203 One 300 mm x 200 mm Both sid Fire Dampers One (sCTjdJl~) 20211 One 300 0101 x 200 mm One side HeatingCooling Coils One (inspedion) 20213 One 300 mm x 200 mm (lIpstream) Both sides Attenuators (rectangular) None required One 300 mm x 200 mm (downstream) Both sides Attenuators (circular) one retluired One 300 mm x 200 mm (downstream) One side Filter Sections One (inspection) 20212 one required Uoth sides Air Turn Vanes None requjred None required Both sides Changes of Direction None required one required One side In-Duct FansDevices One (inspection) 20213 None required Both sides l
1 In the absence of any indication by the designer only Level ) access will be jncorporated into a new ductwork system
2 Tbe panel izes associated with Lev lis I and 3 acee s ar e middottablished by reference to Section 20 of DW144 and Section 2 ofTRll7 respectively
57
DW154 Speclfifatio for Plastics Ductwork
pA XE
B-bliography Included in this Bibliography are technical pUblications which may be of interest (0 ductwork designers fabricators and erectors and to tho e in the heating ventilatlng air conditioning industries generally nquiric should be made of the relevant organisation at the address quoted Since its publication other addresse contained within 0V154 mav have changed and some pubJicalions may have been superseded
HEATING AND VENTILATING CONTRACTORS ASSOCIATION
4 Palace Court London W2 4JG Telephone 020-7229 2488 Fax 020-7727 9268
Orders fo FlY A Publications Old Matlsion House Eamont Bridge Penrith Cumbria CA 10 2BX (Telephone 01768 864771 Fax 01768 86718) Email hvcapoblicationshvwelfarecouk DWn 44 pe ilicatiun for sheet mctal duclwork (Iow- mediulllshy
and high-pressure) 1998) DWIl4 A practical guide to dUGI ork I akage te ting
(revised 2000) DWII54 Specification for plastic~ duct rk DW171 Guide to good Practice for kitchen venlibtion system DW191 Guide to good pracuce glass fibre ductwoJk DwrrMI Acceptance cheme for new products - Redangolar cro
joint classification Guide to good pra tice - Internal cleanliness of new ductwork installations Guide to good practice for the design for the Installation of lire and smoke uampers
J 1Other puhlications
HampV safely guide 5th edition JS2 Tool box talks JS5 Weldlng Safety booklet JSI9 afety facts bo klet Fact sheets 1-24 2nd edition JS2J COSHH manual volume 1 Advice on compliance with the
regulations 1521A CO I-rH manual volume 2 Asses mcnt h ets JS23 Ri k management manual TR3 BrazinltT and bronze welding of copper pipework cUld sheet
(I 976) TR5 Welding of carbon steel pipework (1980)
TR6 Guide to Good Practice for Site Pre sure Testing of Pipework (19 0) Guide to good practice cleanliness of ventilation Ylem
CHARTERED IN TITUTlO OF BUILDING SERVICES E G EERS Delta House 222 Balham High Road London SW12 9BS rTelephone 020-8675 5211 Fax 020-8675 5449) CIBSE Guide Volume A Design Data Volume B In tallatiol1 and quipment Data Volume C Reference Data
CommlssioniJIg Codes These Codes eover the preliminary checkS eUing to work and regulation of vanous catcgories 0 plan The Codes give a guide to design implications Series A Air Distnbution Systems Series B Boiler Plant
ri s C Automatic Conlrol ystems Cr1es R Refrigerating Sy terns
Sene iN Water Distribution Systems
Technkal Memonllda TM 4 Design Notes for the Middle East TM bull Design otes for Ductwork TM 13 Minimi iog lhc Risk of egiounaires Disease
Research Reports RROI95 Ventilation system hygiene - A review of published
infomlatioo on lhe occurrence and ffects of Olltamination Rl~02J95 Air-to-air heal rec v ry RR0395 rnfluen e of HV C on smoke detectors
ATlONAL ENI [ERING SPECIFICATION LfMITED Southgatc hamber 3739 Southgate Street Winchester S023 9EH (Telephone 01962 842058 Fax 01962 R(8982) BUfLDING S RVICES RESEARCH AND [ ORMATION ASSOCIATIO Old Bracknell Lane West Bracknell Berkshire RG 12 4AH (Telephone Brackl1eU (01344) 426511 Fax 01344 487 -7 )
Application Guides AGln4 De tglJing Vana~le Volume middotylans for KOOnl
iir Movement AG1I91 Commissioning of V Sylcms in Buildings 11 6194 Fire Dampers
B) 94 cntiJalion or KitcneTls
AG389 The Commls ionin of Air Systems In Buildmgs AH2192 Commissioning of Bern - A ~ode of Practice TN2417 I Fire Dampec il) Ventilating Ducl
BEATING VENTILATING A AIR CONDITION G MA UFACTURERS ASSOCIATIO (HEVAC) HEVAC Henley Road Medmenham Marlow Buck SU 2ER (Telephone 01491 578674 ox 01491 575024 Emoimiddot infofetacouk)
Publicatjons Air Diffusion Guide Guide to Air Handling Unit Leakage Testing Guide to Good Practice Air Handling Unit Real Room Acoustic ~ st Procedure Specification for the ertiiicatioll ofAir Filters Method of Test for Water Rejection PerfOnTlatce of Louvrcs Subjected 1(1
Simulated Rainfall Test Procedure for Acoustic Loo cs Specification 10 Floor GrilJes - Types Performan e and Method ofTest Specification for the Determination of the Collection Efficiency of SilJ1d
Trap Louvre Domestic Mechwlical Vclltllalion Systems with Heal Recovery Fan Application Guid
~an and Ouctwork Installation Guide Guide to Fan Noise and Vibration
pecification of Requirements for JallJral Smoke and Heal Exhausl Ventilators
pecification for Powered Smoke and Heat Exhaust Ventilators
Specification of Requirements for Smoke Curtains Design Gujue of Smoke Ventilation for Single Storey Lodustrilll Building~
Including those with Mezzanine Floor and IIi Racked Storage Warehou es - Issue 3
Guidance for the Design of Smoke entilation YSlem for Covered and Undergrollnd Car Parks - lssue 1
Application of SOloke Control Equipment and Syst m Guid to Good Practice - Isue J
58
DW154 Sp(C~tiifitiol for Plastics Ductwork
BRITISH STANDARDS INSTIT TION Sales Department 101 P ntooviLle Road London NI 9ND (felephone 020-78 1 78801)
CP 413 1973 Ducts for building ervices
SS 476 Fire tes on building matenals and lruc(ure
Part 4 19 4 Non-combustibility lest or materials
Part 6 I Fire propagation lest for materials
Part 7 1993 Surface spread of tlarnJ tesls for materia
Part 20 1987 Fir resistance of elements of construction
Part 21 1987 Fire r sistlUlce of loadbeanng elements of construction
Part 22 1987 Fhe istallceofllon-loadbearing elemcllts ofconsttuclion Part 23 1987 Contribution of componcnts to the fire resistance 0 a
structure
Part 24t987 Fire resi lance of wl1lilation ductl
SS 5588 nan 919 0 Fire Precautions III thc desIgn and OOSlnJ lion of buildings
S 729 1971 Hot dip galvanized oatiugs (or irOIl aod stcel articles
BS 1449 Steel plate sheet and Irip
Pan 11991 Carbon steel plate heel and strip Part 2 1983 Stainless steel plate sheer and strip
and
B middotENJOI49-2 996 BSEN 10149- 1991)
BSEN 10131 1992
BSEN22063 Sprayed metal coarings 1994 Protection of iron and steel by aluminium and zinc against
atmospheric cOlosion Irotectiotl of iron and ste I against corro ion and oxishydation at elevared temperatures
BS 353 1981 Glossary of lerms relnting to thermal insulation
BS ISO 1479 Self-tapplngscrewsandmetallicdri c crew
B -lSO 7049
1994
B 4800 1989 Painl colour for building purposes B 4848 l0 rolled structural steel sections
Part4 1972 Equal and unequal angles BS 5422 1990 Specification for the use of therm illuating matcriulS
SS 5720 1979 ode of practice for mechanical veutilating and air C 11shy
dirionin bull in building
l3S PR 12814-1 Bend resting for plasric welds
SS PR 12814-2 Tensile testing for plastic welds
SS PR 13067 Appro altesting for plastic welds
BS PR EN I 100-] Vi ual in pection ofplaslic welds
SHEET METAL AND AIR CONDITIONING CONTR-CTORS NATIONAL ASSOCIATION INC (SMACNA) Headquarters 420 I Lafayeue Center Drive Chanlilly Virginia 2051-1209
Mailing Address pa Box 221230 Cbantilly Virginilt120 153-1230
Telephone (703) 803-2980 Fax (703) 803-3732
Accepted IJJdustry Pl3Gtice for Industrial Duct Constnlelion 197 ) i-rchitecmral Sheet kwl Manual ([993)
Comractors Guide lor Modification 10 ooslruerion Colllraets 1993 Ducted Eleclric Heat Guide for ir Handling Ssrerns (1994)
En~rgy ollservatioD Guidelines (1984) Energy Recovery Equipment yslClllS (199l
Fibrou GIns Duct onS1ntClion Standards (1992)
Fire Smoke amp Radiation Damper In tall Guide for HVA Syst ms (1992) Guide t leel Stack 1(95)
HVA Air Duct Leakage Test Manual (19 ) HVA COlllmissioning lvlanual (1994)
H A Duct Construction Standards-Metal amp Flexible (1995) Addendum 01 (Nov 1997)
HVA Duct Systems Inspection Guide (1989)
HVA ySlems-Application (1986) nVAC ByternS-DLlct D ign (1990)
HVi Systems-Testing Adjusting amp Balancing (1993)
indoor Air Quality Manual (1993) tcheu quipment Fabrication Guidelmes (1990)
Managers Guide for elding (1993)
Rectangular Industrial Duct Cons1TUction Standards (19 0) Round Industrial Duct oustmction Standards (1977)
Sei mic Restraint Manual (1991) (wl Appendix E 1993) SMACNA Ma le Index ()fTechnical Publications (1995) Tbennoplnstic Duct CPY ) Construction Manual 1994)
DEPARTME OF THE ENVIRO MENT (Publications Centre) H Stationery Oflice 5 Nine Elms Lane London SWS 5DR
MampEJ 011972 Electrical in tallat1011 in buildings ( ew Editiou)
IampE 0319 Healing hot and cold wat r steam and gas losla1lations for buildings
M amp - No4 1970 Central heating and hot and cold ~ ateT in tallations for
dwelling
M amp ENo100 1971 Mechanical ventilation for building~
ASSOCIATION FOR SPECIALIST FIRE PROTECTlO As ociation House 235 Ash Road AJdershot Hampshire GUl2 4DD
Telephone OJ25221322 Fax 0 J252 333901
lublicalioos Fire Ratcd and moke Outlet Ducrwork An Industry Guide t Design and InSlalla lioll
HEALTH AND SAFETY EXEC TIVE Rose Court 2 Southwark Bridge London SEl 9HS Telephone 020-7717 6000
TWJ THE WELD G TlTUTE Abington Hall Abington Cambridge CB16AL Telepbone 0 J223 89162
Publication DatJ Oil w~ldll1g of lhermopla lics
59
DW154 wciiwlioll for Plastics Ductwork
A -=--DIX
Factors
Specific gravity shy pp = 091 approx UPVC = 14 approx
Some miscellaneous conversion factors
To convert
Length Inches to millimetres Feet to metres
Multiply by
2540 03048
To convert
Millimetres to inches Metres to feet
vIultiply by
003937 3281
Area Square inches to square millimetres 6452 Square millimetres to square inches 000155 Square feet to square metres 00929 Square metres to square feet 10764
Volume Cubic feet to cubic metres Cubic feet to litres Gallons (UK) to litres
002832 2831 4546
Cubic metres to cubic feet Litres to cubic feet Litres to gallons (UK)
35315 00353
022
Mass Ounces to grams Pounds to kiJograms Tons to tonnes
2835 04536
1016
Grams to ounces Kilograms to pounds Tonnes to tons
003527 2205
09842
Volume flow Cubic feet per minute to cubic Cubic metres per second to cubic
metres per second 0000472 feet per minute 2119 Cubic feet per mIDute to litres Litres per second to cubic feet
per second 04719 per minute 2119
Motion Feet per minute to metres per second 000508 Metres per second to feet per minute 197
Pressure Inches water gauge to millibars 2491 Inches wateJ- gauge to pascals (Pa) 2491 I Pa = I ewton per square metre = 10-2 millibars
60
Heating and Ventilating Contractors Association Esca House 34 Palace Court London W2 4JG
Tel 020 7313 4900
e-mail contact Itvcaorguk web site wwwhvcaorguk
Fax 020 7727 9268
DW154 S1tciic(ltioll for Plastics Ductwork
85 Internal cleanliness of new ductwork The site storage of ductwork introduces the important cODsideration of maintaining the internal cleanliness of the ductwork R feren e should be made to HVCA documentshybull DWffM2 Guide to Good Practice - internal
Cleanliness of New Ductwork Installations If the above conditioDs can not be satisfied consideration should be given by tJle designer to amending the specification to include for Po t Installation Cleaning as covered by tJ1C HVCA documentshybull TRJ17 Guide to Good Practic - Cleanliness
of Ventilation Systems
APPE DIXC
Fi e Retardant inishes C1 Improvement in the fire retardancy of plastic
ducts can be achieved to varying degrees and is wholly dependent llPOll the surface coating laminating resin selected and construction specification adopted In some instances smoke emission is coILSidered equaUy with other speci fication requirernen ts of the materials resistance to ignition and bumjng It is therefore important for design rs to establ ish the clients and officers detailed requirements and not rely on a tbird party interpretation of fire resisting or fire retardant Where possible the specification should refer dir etly to compliance with a British or European Standard identifying the specific sections applicable There are various types of resin and mat rcLnforcements that can achieve a Class 1 surface spread of flame ratin o when tested according to BS476 Part 7 (1987) This test puts materials illto Class I - 4 in descending order of perfoDllance according to the rat and extent of flame spread over their surfac under standard beating conditions Materials should also be tested for flre propagarion to BS476 Part 6 (1989) Tbi tesr measures the amount and rate of heat evolved by the material when subjected to standard heating
conditions Test results are given as an index of Perfonnance (i) whicb is based on three sub indices (iJ (i1) (h) The higher the value of the Index of Performance (i) the greater is the material s contribution to fire growth The higher the value of the sub-index 0) rhe greater the ease of ignition aod flame spread The highest product performance classification as defined in Approved Document B of the Building Regulations is Class O This is acLlieved if a material surface of a composite ploduct i~ either a) composed throughout of materials of
limited combustibility or b) a Class I material which has a tlre
propagation index (i) of not more than 12 and sub-index (i l ) of nor more than 6
01 J Class 0 is not a cla$sif1cation identified in any British Standard test
There are resin system reported to be classified to Class O when tested to BS476 Pcl1S 6 and 7 however designers need to ensure that such sysrems can be applied to their proposed design In propriety resinmat system available the fabrication techniques and COITect application are critical to the integrity of the reinforcing and clas ificatiol1 For example in some systems the u e of a non-fire retardant gelcont on a fire retardant substrate would reduce the classification For further information see HVCA publication DW144 Appendix D
55
DW154 SplCijiClIliol1 for Plastics Ductwork
x Guidance otes For nspectmiddoton Servicing a d
Clean-ng Access Openings
D1 GE ERAL This appendix highlight in ummary fOI111
the acce considerations that hould be made by the design r iD terms of inspection servicing and cleaning Having considered the seop and the design of the dUCI work system relative to the guidelines outlined below the designer should clearly indicate which levels of acces should be incorporated into the manufacture of a new duct work system (See Table 14 and Note I b low it
D2 DESIGN CONSIDERATIONS
D21 In ptction and servicing requireshyments are set out in Section 15 of Lhis specification
D22 Cleaning requirements are set out in the HVCA pubUcation TRl7 Guide to Good Practice Clean Lines of Ventilation Systems and the guide tates The precise location ize and
type of access would be dependent on the type of ductwork cleaning inspection and te ting metbods to b adopted Care protection and standards of cleanliness prior LO cOlllmisionin o
are set out in th AV A publication DWITM2 Guide to Good Practice Internal Cleanliness of New Ductwork Installations and th guide state Wh re specific limits of cleanliness are required ductwork sball be cleaned after installation by a spcialist cleaning contractor It will b in the interests of tht desioner botb financially and practically to cunsider employing a specialist c1eauing contractor at tbe
outset of a contract to internally clean newly installed ductwork prior to bandover This approach would reali e the following benefit shyi) Tb actual numb r of cleaning
access panels could be detennined to suit the method of cleaning to be adopted (This may be 1 s than the maximum requiremen listed under Lev 13 of Table 14)
ii) Clear directions could b given to the ductwork contractor as to tJle size and location of cleaning access panels that are required to be fitted during the mauushyfaclunng pro s
iii) The specialist cleaning operation prior to commi ioning vould enable the cleaning contractor to verify the practical acee requirement for the future cleaning operation associated -vitb a regular maintenance programme
iv) A specialist cleaning operation prior to commissioning would allow the designer to omit from the speeilicatiolJ the DWrrM2 requirem nt for factory sealing protection wipe downs and capping-off
v) Specialist Ieall ill 0 to the measurable standard defin d in TR17 will allow an objective definition of cleanline to be achieved
Car ful consideration must be gIven by the designer to the practl aJ problems associated witb the manufacture and fitting of suitably si Led access panel on small cross section duct and on the circular faces of rouod and flat oval ducts in particular
D23 Special con ideration must be given by the de igner to the practical problems associated with gaining personnel access to heavily congested ceiling areas and multi-la red du twork systems This approach would avoid
56
DW154 Spfciication for Plastics Ductwork
the possibility of access panels being D3 ACCESS 0 IN-LINE EQUIPMENT incorporated into a ductwork system at the This appendix unly covers acc il1spection manufacturing stage that were later found in through the ductwork body adjacent to an item practice to be inaccessible for either ervicing of in-line equipment and not openings in the or cleaning activities equipment itself
able 14 Acce requirements for inspection servicing and cleaning
HVCA PUBLICATIO REFE NeE (uidtgt 10 Gund Prartict
Adjace t OW144 Cleanliness orVcnlillltio S~lcr~ fRjJ7
in-line LeyeJ 1 Level 2 Level 3 ite sequipment pcdionSen lcin~ Section d C1eaniJl( SUn(O)lnspc lion Palle ltk~m_n
2011 (minimum OiL Jubje-ct to duct ~zel (ft~ -Panels
Control Da pcrs One (inspection) 203 One 300 mm x 200 mm Both sid Fire Dampers One (sCTjdJl~) 20211 One 300 0101 x 200 mm One side HeatingCooling Coils One (inspedion) 20213 One 300 mm x 200 mm (lIpstream) Both sides Attenuators (rectangular) None required One 300 mm x 200 mm (downstream) Both sides Attenuators (circular) one retluired One 300 mm x 200 mm (downstream) One side Filter Sections One (inspection) 20212 one required Uoth sides Air Turn Vanes None requjred None required Both sides Changes of Direction None required one required One side In-Duct FansDevices One (inspection) 20213 None required Both sides l
1 In the absence of any indication by the designer only Level ) access will be jncorporated into a new ductwork system
2 Tbe panel izes associated with Lev lis I and 3 acee s ar e middottablished by reference to Section 20 of DW144 and Section 2 ofTRll7 respectively
57
DW154 Speclfifatio for Plastics Ductwork
pA XE
B-bliography Included in this Bibliography are technical pUblications which may be of interest (0 ductwork designers fabricators and erectors and to tho e in the heating ventilatlng air conditioning industries generally nquiric should be made of the relevant organisation at the address quoted Since its publication other addresse contained within 0V154 mav have changed and some pubJicalions may have been superseded
HEATING AND VENTILATING CONTRACTORS ASSOCIATION
4 Palace Court London W2 4JG Telephone 020-7229 2488 Fax 020-7727 9268
Orders fo FlY A Publications Old Matlsion House Eamont Bridge Penrith Cumbria CA 10 2BX (Telephone 01768 864771 Fax 01768 86718) Email hvcapoblicationshvwelfarecouk DWn 44 pe ilicatiun for sheet mctal duclwork (Iow- mediulllshy
and high-pressure) 1998) DWIl4 A practical guide to dUGI ork I akage te ting
(revised 2000) DWII54 Specification for plastic~ duct rk DW171 Guide to good Practice for kitchen venlibtion system DW191 Guide to good pracuce glass fibre ductwoJk DwrrMI Acceptance cheme for new products - Redangolar cro
joint classification Guide to good pra tice - Internal cleanliness of new ductwork installations Guide to good practice for the design for the Installation of lire and smoke uampers
J 1Other puhlications
HampV safely guide 5th edition JS2 Tool box talks JS5 Weldlng Safety booklet JSI9 afety facts bo klet Fact sheets 1-24 2nd edition JS2J COSHH manual volume 1 Advice on compliance with the
regulations 1521A CO I-rH manual volume 2 Asses mcnt h ets JS23 Ri k management manual TR3 BrazinltT and bronze welding of copper pipework cUld sheet
(I 976) TR5 Welding of carbon steel pipework (1980)
TR6 Guide to Good Practice for Site Pre sure Testing of Pipework (19 0) Guide to good practice cleanliness of ventilation Ylem
CHARTERED IN TITUTlO OF BUILDING SERVICES E G EERS Delta House 222 Balham High Road London SW12 9BS rTelephone 020-8675 5211 Fax 020-8675 5449) CIBSE Guide Volume A Design Data Volume B In tallatiol1 and quipment Data Volume C Reference Data
CommlssioniJIg Codes These Codes eover the preliminary checkS eUing to work and regulation of vanous catcgories 0 plan The Codes give a guide to design implications Series A Air Distnbution Systems Series B Boiler Plant
ri s C Automatic Conlrol ystems Cr1es R Refrigerating Sy terns
Sene iN Water Distribution Systems
Technkal Memonllda TM 4 Design Notes for the Middle East TM bull Design otes for Ductwork TM 13 Minimi iog lhc Risk of egiounaires Disease
Research Reports RROI95 Ventilation system hygiene - A review of published
infomlatioo on lhe occurrence and ffects of Olltamination Rl~02J95 Air-to-air heal rec v ry RR0395 rnfluen e of HV C on smoke detectors
ATlONAL ENI [ERING SPECIFICATION LfMITED Southgatc hamber 3739 Southgate Street Winchester S023 9EH (Telephone 01962 842058 Fax 01962 R(8982) BUfLDING S RVICES RESEARCH AND [ ORMATION ASSOCIATIO Old Bracknell Lane West Bracknell Berkshire RG 12 4AH (Telephone Brackl1eU (01344) 426511 Fax 01344 487 -7 )
Application Guides AGln4 De tglJing Vana~le Volume middotylans for KOOnl
iir Movement AG1I91 Commissioning of V Sylcms in Buildings 11 6194 Fire Dampers
B) 94 cntiJalion or KitcneTls
AG389 The Commls ionin of Air Systems In Buildmgs AH2192 Commissioning of Bern - A ~ode of Practice TN2417 I Fire Dampec il) Ventilating Ducl
BEATING VENTILATING A AIR CONDITION G MA UFACTURERS ASSOCIATIO (HEVAC) HEVAC Henley Road Medmenham Marlow Buck SU 2ER (Telephone 01491 578674 ox 01491 575024 Emoimiddot infofetacouk)
Publicatjons Air Diffusion Guide Guide to Air Handling Unit Leakage Testing Guide to Good Practice Air Handling Unit Real Room Acoustic ~ st Procedure Specification for the ertiiicatioll ofAir Filters Method of Test for Water Rejection PerfOnTlatce of Louvrcs Subjected 1(1
Simulated Rainfall Test Procedure for Acoustic Loo cs Specification 10 Floor GrilJes - Types Performan e and Method ofTest Specification for the Determination of the Collection Efficiency of SilJ1d
Trap Louvre Domestic Mechwlical Vclltllalion Systems with Heal Recovery Fan Application Guid
~an and Ouctwork Installation Guide Guide to Fan Noise and Vibration
pecification of Requirements for JallJral Smoke and Heal Exhausl Ventilators
pecification for Powered Smoke and Heat Exhaust Ventilators
Specification of Requirements for Smoke Curtains Design Gujue of Smoke Ventilation for Single Storey Lodustrilll Building~
Including those with Mezzanine Floor and IIi Racked Storage Warehou es - Issue 3
Guidance for the Design of Smoke entilation YSlem for Covered and Undergrollnd Car Parks - lssue 1
Application of SOloke Control Equipment and Syst m Guid to Good Practice - Isue J
58
DW154 Sp(C~tiifitiol for Plastics Ductwork
BRITISH STANDARDS INSTIT TION Sales Department 101 P ntooviLle Road London NI 9ND (felephone 020-78 1 78801)
CP 413 1973 Ducts for building ervices
SS 476 Fire tes on building matenals and lruc(ure
Part 4 19 4 Non-combustibility lest or materials
Part 6 I Fire propagation lest for materials
Part 7 1993 Surface spread of tlarnJ tesls for materia
Part 20 1987 Fir resistance of elements of construction
Part 21 1987 Fire r sistlUlce of loadbeanng elements of construction
Part 22 1987 Fhe istallceofllon-loadbearing elemcllts ofconsttuclion Part 23 1987 Contribution of componcnts to the fire resistance 0 a
structure
Part 24t987 Fire resi lance of wl1lilation ductl
SS 5588 nan 919 0 Fire Precautions III thc desIgn and OOSlnJ lion of buildings
S 729 1971 Hot dip galvanized oatiugs (or irOIl aod stcel articles
BS 1449 Steel plate sheet and Irip
Pan 11991 Carbon steel plate heel and strip Part 2 1983 Stainless steel plate sheer and strip
and
B middotENJOI49-2 996 BSEN 10149- 1991)
BSEN 10131 1992
BSEN22063 Sprayed metal coarings 1994 Protection of iron and steel by aluminium and zinc against
atmospheric cOlosion Irotectiotl of iron and ste I against corro ion and oxishydation at elevared temperatures
BS 353 1981 Glossary of lerms relnting to thermal insulation
BS ISO 1479 Self-tapplngscrewsandmetallicdri c crew
B -lSO 7049
1994
B 4800 1989 Painl colour for building purposes B 4848 l0 rolled structural steel sections
Part4 1972 Equal and unequal angles BS 5422 1990 Specification for the use of therm illuating matcriulS
SS 5720 1979 ode of practice for mechanical veutilating and air C 11shy
dirionin bull in building
l3S PR 12814-1 Bend resting for plasric welds
SS PR 12814-2 Tensile testing for plastic welds
SS PR 13067 Appro altesting for plastic welds
BS PR EN I 100-] Vi ual in pection ofplaslic welds
SHEET METAL AND AIR CONDITIONING CONTR-CTORS NATIONAL ASSOCIATION INC (SMACNA) Headquarters 420 I Lafayeue Center Drive Chanlilly Virginia 2051-1209
Mailing Address pa Box 221230 Cbantilly Virginilt120 153-1230
Telephone (703) 803-2980 Fax (703) 803-3732
Accepted IJJdustry Pl3Gtice for Industrial Duct Constnlelion 197 ) i-rchitecmral Sheet kwl Manual ([993)
Comractors Guide lor Modification 10 ooslruerion Colllraets 1993 Ducted Eleclric Heat Guide for ir Handling Ssrerns (1994)
En~rgy ollservatioD Guidelines (1984) Energy Recovery Equipment yslClllS (199l
Fibrou GIns Duct onS1ntClion Standards (1992)
Fire Smoke amp Radiation Damper In tall Guide for HVA Syst ms (1992) Guide t leel Stack 1(95)
HVA Air Duct Leakage Test Manual (19 ) HVA COlllmissioning lvlanual (1994)
H A Duct Construction Standards-Metal amp Flexible (1995) Addendum 01 (Nov 1997)
HVA Duct Systems Inspection Guide (1989)
HVA ySlems-Application (1986) nVAC ByternS-DLlct D ign (1990)
HVi Systems-Testing Adjusting amp Balancing (1993)
indoor Air Quality Manual (1993) tcheu quipment Fabrication Guidelmes (1990)
Managers Guide for elding (1993)
Rectangular Industrial Duct Cons1TUction Standards (19 0) Round Industrial Duct oustmction Standards (1977)
Sei mic Restraint Manual (1991) (wl Appendix E 1993) SMACNA Ma le Index ()fTechnical Publications (1995) Tbennoplnstic Duct CPY ) Construction Manual 1994)
DEPARTME OF THE ENVIRO MENT (Publications Centre) H Stationery Oflice 5 Nine Elms Lane London SWS 5DR
MampEJ 011972 Electrical in tallat1011 in buildings ( ew Editiou)
IampE 0319 Healing hot and cold wat r steam and gas losla1lations for buildings
M amp - No4 1970 Central heating and hot and cold ~ ateT in tallations for
dwelling
M amp ENo100 1971 Mechanical ventilation for building~
ASSOCIATION FOR SPECIALIST FIRE PROTECTlO As ociation House 235 Ash Road AJdershot Hampshire GUl2 4DD
Telephone OJ25221322 Fax 0 J252 333901
lublicalioos Fire Ratcd and moke Outlet Ducrwork An Industry Guide t Design and InSlalla lioll
HEALTH AND SAFETY EXEC TIVE Rose Court 2 Southwark Bridge London SEl 9HS Telephone 020-7717 6000
TWJ THE WELD G TlTUTE Abington Hall Abington Cambridge CB16AL Telepbone 0 J223 89162
Publication DatJ Oil w~ldll1g of lhermopla lics
59
DW154 wciiwlioll for Plastics Ductwork
A -=--DIX
Factors
Specific gravity shy pp = 091 approx UPVC = 14 approx
Some miscellaneous conversion factors
To convert
Length Inches to millimetres Feet to metres
Multiply by
2540 03048
To convert
Millimetres to inches Metres to feet
vIultiply by
003937 3281
Area Square inches to square millimetres 6452 Square millimetres to square inches 000155 Square feet to square metres 00929 Square metres to square feet 10764
Volume Cubic feet to cubic metres Cubic feet to litres Gallons (UK) to litres
002832 2831 4546
Cubic metres to cubic feet Litres to cubic feet Litres to gallons (UK)
35315 00353
022
Mass Ounces to grams Pounds to kiJograms Tons to tonnes
2835 04536
1016
Grams to ounces Kilograms to pounds Tonnes to tons
003527 2205
09842
Volume flow Cubic feet per minute to cubic Cubic metres per second to cubic
metres per second 0000472 feet per minute 2119 Cubic feet per mIDute to litres Litres per second to cubic feet
per second 04719 per minute 2119
Motion Feet per minute to metres per second 000508 Metres per second to feet per minute 197
Pressure Inches water gauge to millibars 2491 Inches wateJ- gauge to pascals (Pa) 2491 I Pa = I ewton per square metre = 10-2 millibars
60
Heating and Ventilating Contractors Association Esca House 34 Palace Court London W2 4JG
Tel 020 7313 4900
e-mail contact Itvcaorguk web site wwwhvcaorguk
Fax 020 7727 9268
DW154 SplCijiClIliol1 for Plastics Ductwork
x Guidance otes For nspectmiddoton Servicing a d
Clean-ng Access Openings
D1 GE ERAL This appendix highlight in ummary fOI111
the acce considerations that hould be made by the design r iD terms of inspection servicing and cleaning Having considered the seop and the design of the dUCI work system relative to the guidelines outlined below the designer should clearly indicate which levels of acces should be incorporated into the manufacture of a new duct work system (See Table 14 and Note I b low it
D2 DESIGN CONSIDERATIONS
D21 In ptction and servicing requireshyments are set out in Section 15 of Lhis specification
D22 Cleaning requirements are set out in the HVCA pubUcation TRl7 Guide to Good Practice Clean Lines of Ventilation Systems and the guide tates The precise location ize and
type of access would be dependent on the type of ductwork cleaning inspection and te ting metbods to b adopted Care protection and standards of cleanliness prior LO cOlllmisionin o
are set out in th AV A publication DWITM2 Guide to Good Practice Internal Cleanliness of New Ductwork Installations and th guide state Wh re specific limits of cleanliness are required ductwork sball be cleaned after installation by a spcialist cleaning contractor It will b in the interests of tht desioner botb financially and practically to cunsider employing a specialist c1eauing contractor at tbe
outset of a contract to internally clean newly installed ductwork prior to bandover This approach would reali e the following benefit shyi) Tb actual numb r of cleaning
access panels could be detennined to suit the method of cleaning to be adopted (This may be 1 s than the maximum requiremen listed under Lev 13 of Table 14)
ii) Clear directions could b given to the ductwork contractor as to tJle size and location of cleaning access panels that are required to be fitted during the mauushyfaclunng pro s
iii) The specialist cleaning operation prior to commi ioning vould enable the cleaning contractor to verify the practical acee requirement for the future cleaning operation associated -vitb a regular maintenance programme
iv) A specialist cleaning operation prior to commissioning would allow the designer to omit from the speeilicatiolJ the DWrrM2 requirem nt for factory sealing protection wipe downs and capping-off
v) Specialist Ieall ill 0 to the measurable standard defin d in TR17 will allow an objective definition of cleanline to be achieved
Car ful consideration must be gIven by the designer to the practl aJ problems associated witb the manufacture and fitting of suitably si Led access panel on small cross section duct and on the circular faces of rouod and flat oval ducts in particular
D23 Special con ideration must be given by the de igner to the practical problems associated with gaining personnel access to heavily congested ceiling areas and multi-la red du twork systems This approach would avoid
56
DW154 Spfciication for Plastics Ductwork
the possibility of access panels being D3 ACCESS 0 IN-LINE EQUIPMENT incorporated into a ductwork system at the This appendix unly covers acc il1spection manufacturing stage that were later found in through the ductwork body adjacent to an item practice to be inaccessible for either ervicing of in-line equipment and not openings in the or cleaning activities equipment itself
able 14 Acce requirements for inspection servicing and cleaning
HVCA PUBLICATIO REFE NeE (uidtgt 10 Gund Prartict
Adjace t OW144 Cleanliness orVcnlillltio S~lcr~ fRjJ7
in-line LeyeJ 1 Level 2 Level 3 ite sequipment pcdionSen lcin~ Section d C1eaniJl( SUn(O)lnspc lion Palle ltk~m_n
2011 (minimum OiL Jubje-ct to duct ~zel (ft~ -Panels
Control Da pcrs One (inspection) 203 One 300 mm x 200 mm Both sid Fire Dampers One (sCTjdJl~) 20211 One 300 0101 x 200 mm One side HeatingCooling Coils One (inspedion) 20213 One 300 mm x 200 mm (lIpstream) Both sides Attenuators (rectangular) None required One 300 mm x 200 mm (downstream) Both sides Attenuators (circular) one retluired One 300 mm x 200 mm (downstream) One side Filter Sections One (inspection) 20212 one required Uoth sides Air Turn Vanes None requjred None required Both sides Changes of Direction None required one required One side In-Duct FansDevices One (inspection) 20213 None required Both sides l
1 In the absence of any indication by the designer only Level ) access will be jncorporated into a new ductwork system
2 Tbe panel izes associated with Lev lis I and 3 acee s ar e middottablished by reference to Section 20 of DW144 and Section 2 ofTRll7 respectively
57
DW154 Speclfifatio for Plastics Ductwork
pA XE
B-bliography Included in this Bibliography are technical pUblications which may be of interest (0 ductwork designers fabricators and erectors and to tho e in the heating ventilatlng air conditioning industries generally nquiric should be made of the relevant organisation at the address quoted Since its publication other addresse contained within 0V154 mav have changed and some pubJicalions may have been superseded
HEATING AND VENTILATING CONTRACTORS ASSOCIATION
4 Palace Court London W2 4JG Telephone 020-7229 2488 Fax 020-7727 9268
Orders fo FlY A Publications Old Matlsion House Eamont Bridge Penrith Cumbria CA 10 2BX (Telephone 01768 864771 Fax 01768 86718) Email hvcapoblicationshvwelfarecouk DWn 44 pe ilicatiun for sheet mctal duclwork (Iow- mediulllshy
and high-pressure) 1998) DWIl4 A practical guide to dUGI ork I akage te ting
(revised 2000) DWII54 Specification for plastic~ duct rk DW171 Guide to good Practice for kitchen venlibtion system DW191 Guide to good pracuce glass fibre ductwoJk DwrrMI Acceptance cheme for new products - Redangolar cro
joint classification Guide to good pra tice - Internal cleanliness of new ductwork installations Guide to good practice for the design for the Installation of lire and smoke uampers
J 1Other puhlications
HampV safely guide 5th edition JS2 Tool box talks JS5 Weldlng Safety booklet JSI9 afety facts bo klet Fact sheets 1-24 2nd edition JS2J COSHH manual volume 1 Advice on compliance with the
regulations 1521A CO I-rH manual volume 2 Asses mcnt h ets JS23 Ri k management manual TR3 BrazinltT and bronze welding of copper pipework cUld sheet
(I 976) TR5 Welding of carbon steel pipework (1980)
TR6 Guide to Good Practice for Site Pre sure Testing of Pipework (19 0) Guide to good practice cleanliness of ventilation Ylem
CHARTERED IN TITUTlO OF BUILDING SERVICES E G EERS Delta House 222 Balham High Road London SW12 9BS rTelephone 020-8675 5211 Fax 020-8675 5449) CIBSE Guide Volume A Design Data Volume B In tallatiol1 and quipment Data Volume C Reference Data
CommlssioniJIg Codes These Codes eover the preliminary checkS eUing to work and regulation of vanous catcgories 0 plan The Codes give a guide to design implications Series A Air Distnbution Systems Series B Boiler Plant
ri s C Automatic Conlrol ystems Cr1es R Refrigerating Sy terns
Sene iN Water Distribution Systems
Technkal Memonllda TM 4 Design Notes for the Middle East TM bull Design otes for Ductwork TM 13 Minimi iog lhc Risk of egiounaires Disease
Research Reports RROI95 Ventilation system hygiene - A review of published
infomlatioo on lhe occurrence and ffects of Olltamination Rl~02J95 Air-to-air heal rec v ry RR0395 rnfluen e of HV C on smoke detectors
ATlONAL ENI [ERING SPECIFICATION LfMITED Southgatc hamber 3739 Southgate Street Winchester S023 9EH (Telephone 01962 842058 Fax 01962 R(8982) BUfLDING S RVICES RESEARCH AND [ ORMATION ASSOCIATIO Old Bracknell Lane West Bracknell Berkshire RG 12 4AH (Telephone Brackl1eU (01344) 426511 Fax 01344 487 -7 )
Application Guides AGln4 De tglJing Vana~le Volume middotylans for KOOnl
iir Movement AG1I91 Commissioning of V Sylcms in Buildings 11 6194 Fire Dampers
B) 94 cntiJalion or KitcneTls
AG389 The Commls ionin of Air Systems In Buildmgs AH2192 Commissioning of Bern - A ~ode of Practice TN2417 I Fire Dampec il) Ventilating Ducl
BEATING VENTILATING A AIR CONDITION G MA UFACTURERS ASSOCIATIO (HEVAC) HEVAC Henley Road Medmenham Marlow Buck SU 2ER (Telephone 01491 578674 ox 01491 575024 Emoimiddot infofetacouk)
Publicatjons Air Diffusion Guide Guide to Air Handling Unit Leakage Testing Guide to Good Practice Air Handling Unit Real Room Acoustic ~ st Procedure Specification for the ertiiicatioll ofAir Filters Method of Test for Water Rejection PerfOnTlatce of Louvrcs Subjected 1(1
Simulated Rainfall Test Procedure for Acoustic Loo cs Specification 10 Floor GrilJes - Types Performan e and Method ofTest Specification for the Determination of the Collection Efficiency of SilJ1d
Trap Louvre Domestic Mechwlical Vclltllalion Systems with Heal Recovery Fan Application Guid
~an and Ouctwork Installation Guide Guide to Fan Noise and Vibration
pecification of Requirements for JallJral Smoke and Heal Exhausl Ventilators
pecification for Powered Smoke and Heat Exhaust Ventilators
Specification of Requirements for Smoke Curtains Design Gujue of Smoke Ventilation for Single Storey Lodustrilll Building~
Including those with Mezzanine Floor and IIi Racked Storage Warehou es - Issue 3
Guidance for the Design of Smoke entilation YSlem for Covered and Undergrollnd Car Parks - lssue 1
Application of SOloke Control Equipment and Syst m Guid to Good Practice - Isue J
58
DW154 Sp(C~tiifitiol for Plastics Ductwork
BRITISH STANDARDS INSTIT TION Sales Department 101 P ntooviLle Road London NI 9ND (felephone 020-78 1 78801)
CP 413 1973 Ducts for building ervices
SS 476 Fire tes on building matenals and lruc(ure
Part 4 19 4 Non-combustibility lest or materials
Part 6 I Fire propagation lest for materials
Part 7 1993 Surface spread of tlarnJ tesls for materia
Part 20 1987 Fir resistance of elements of construction
Part 21 1987 Fire r sistlUlce of loadbeanng elements of construction
Part 22 1987 Fhe istallceofllon-loadbearing elemcllts ofconsttuclion Part 23 1987 Contribution of componcnts to the fire resistance 0 a
structure
Part 24t987 Fire resi lance of wl1lilation ductl
SS 5588 nan 919 0 Fire Precautions III thc desIgn and OOSlnJ lion of buildings
S 729 1971 Hot dip galvanized oatiugs (or irOIl aod stcel articles
BS 1449 Steel plate sheet and Irip
Pan 11991 Carbon steel plate heel and strip Part 2 1983 Stainless steel plate sheer and strip
and
B middotENJOI49-2 996 BSEN 10149- 1991)
BSEN 10131 1992
BSEN22063 Sprayed metal coarings 1994 Protection of iron and steel by aluminium and zinc against
atmospheric cOlosion Irotectiotl of iron and ste I against corro ion and oxishydation at elevared temperatures
BS 353 1981 Glossary of lerms relnting to thermal insulation
BS ISO 1479 Self-tapplngscrewsandmetallicdri c crew
B -lSO 7049
1994
B 4800 1989 Painl colour for building purposes B 4848 l0 rolled structural steel sections
Part4 1972 Equal and unequal angles BS 5422 1990 Specification for the use of therm illuating matcriulS
SS 5720 1979 ode of practice for mechanical veutilating and air C 11shy
dirionin bull in building
l3S PR 12814-1 Bend resting for plasric welds
SS PR 12814-2 Tensile testing for plastic welds
SS PR 13067 Appro altesting for plastic welds
BS PR EN I 100-] Vi ual in pection ofplaslic welds
SHEET METAL AND AIR CONDITIONING CONTR-CTORS NATIONAL ASSOCIATION INC (SMACNA) Headquarters 420 I Lafayeue Center Drive Chanlilly Virginia 2051-1209
Mailing Address pa Box 221230 Cbantilly Virginilt120 153-1230
Telephone (703) 803-2980 Fax (703) 803-3732
Accepted IJJdustry Pl3Gtice for Industrial Duct Constnlelion 197 ) i-rchitecmral Sheet kwl Manual ([993)
Comractors Guide lor Modification 10 ooslruerion Colllraets 1993 Ducted Eleclric Heat Guide for ir Handling Ssrerns (1994)
En~rgy ollservatioD Guidelines (1984) Energy Recovery Equipment yslClllS (199l
Fibrou GIns Duct onS1ntClion Standards (1992)
Fire Smoke amp Radiation Damper In tall Guide for HVA Syst ms (1992) Guide t leel Stack 1(95)
HVA Air Duct Leakage Test Manual (19 ) HVA COlllmissioning lvlanual (1994)
H A Duct Construction Standards-Metal amp Flexible (1995) Addendum 01 (Nov 1997)
HVA Duct Systems Inspection Guide (1989)
HVA ySlems-Application (1986) nVAC ByternS-DLlct D ign (1990)
HVi Systems-Testing Adjusting amp Balancing (1993)
indoor Air Quality Manual (1993) tcheu quipment Fabrication Guidelmes (1990)
Managers Guide for elding (1993)
Rectangular Industrial Duct Cons1TUction Standards (19 0) Round Industrial Duct oustmction Standards (1977)
Sei mic Restraint Manual (1991) (wl Appendix E 1993) SMACNA Ma le Index ()fTechnical Publications (1995) Tbennoplnstic Duct CPY ) Construction Manual 1994)
DEPARTME OF THE ENVIRO MENT (Publications Centre) H Stationery Oflice 5 Nine Elms Lane London SWS 5DR
MampEJ 011972 Electrical in tallat1011 in buildings ( ew Editiou)
IampE 0319 Healing hot and cold wat r steam and gas losla1lations for buildings
M amp - No4 1970 Central heating and hot and cold ~ ateT in tallations for
dwelling
M amp ENo100 1971 Mechanical ventilation for building~
ASSOCIATION FOR SPECIALIST FIRE PROTECTlO As ociation House 235 Ash Road AJdershot Hampshire GUl2 4DD
Telephone OJ25221322 Fax 0 J252 333901
lublicalioos Fire Ratcd and moke Outlet Ducrwork An Industry Guide t Design and InSlalla lioll
HEALTH AND SAFETY EXEC TIVE Rose Court 2 Southwark Bridge London SEl 9HS Telephone 020-7717 6000
TWJ THE WELD G TlTUTE Abington Hall Abington Cambridge CB16AL Telepbone 0 J223 89162
Publication DatJ Oil w~ldll1g of lhermopla lics
59
DW154 wciiwlioll for Plastics Ductwork
A -=--DIX
Factors
Specific gravity shy pp = 091 approx UPVC = 14 approx
Some miscellaneous conversion factors
To convert
Length Inches to millimetres Feet to metres
Multiply by
2540 03048
To convert
Millimetres to inches Metres to feet
vIultiply by
003937 3281
Area Square inches to square millimetres 6452 Square millimetres to square inches 000155 Square feet to square metres 00929 Square metres to square feet 10764
Volume Cubic feet to cubic metres Cubic feet to litres Gallons (UK) to litres
002832 2831 4546
Cubic metres to cubic feet Litres to cubic feet Litres to gallons (UK)
35315 00353
022
Mass Ounces to grams Pounds to kiJograms Tons to tonnes
2835 04536
1016
Grams to ounces Kilograms to pounds Tonnes to tons
003527 2205
09842
Volume flow Cubic feet per minute to cubic Cubic metres per second to cubic
metres per second 0000472 feet per minute 2119 Cubic feet per mIDute to litres Litres per second to cubic feet
per second 04719 per minute 2119
Motion Feet per minute to metres per second 000508 Metres per second to feet per minute 197
Pressure Inches water gauge to millibars 2491 Inches wateJ- gauge to pascals (Pa) 2491 I Pa = I ewton per square metre = 10-2 millibars
60
Heating and Ventilating Contractors Association Esca House 34 Palace Court London W2 4JG
Tel 020 7313 4900
e-mail contact Itvcaorguk web site wwwhvcaorguk
Fax 020 7727 9268
DW154 Spfciication for Plastics Ductwork
the possibility of access panels being D3 ACCESS 0 IN-LINE EQUIPMENT incorporated into a ductwork system at the This appendix unly covers acc il1spection manufacturing stage that were later found in through the ductwork body adjacent to an item practice to be inaccessible for either ervicing of in-line equipment and not openings in the or cleaning activities equipment itself
able 14 Acce requirements for inspection servicing and cleaning
HVCA PUBLICATIO REFE NeE (uidtgt 10 Gund Prartict
Adjace t OW144 Cleanliness orVcnlillltio S~lcr~ fRjJ7
in-line LeyeJ 1 Level 2 Level 3 ite sequipment pcdionSen lcin~ Section d C1eaniJl( SUn(O)lnspc lion Palle ltk~m_n
2011 (minimum OiL Jubje-ct to duct ~zel (ft~ -Panels
Control Da pcrs One (inspection) 203 One 300 mm x 200 mm Both sid Fire Dampers One (sCTjdJl~) 20211 One 300 0101 x 200 mm One side HeatingCooling Coils One (inspedion) 20213 One 300 mm x 200 mm (lIpstream) Both sides Attenuators (rectangular) None required One 300 mm x 200 mm (downstream) Both sides Attenuators (circular) one retluired One 300 mm x 200 mm (downstream) One side Filter Sections One (inspection) 20212 one required Uoth sides Air Turn Vanes None requjred None required Both sides Changes of Direction None required one required One side In-Duct FansDevices One (inspection) 20213 None required Both sides l
1 In the absence of any indication by the designer only Level ) access will be jncorporated into a new ductwork system
2 Tbe panel izes associated with Lev lis I and 3 acee s ar e middottablished by reference to Section 20 of DW144 and Section 2 ofTRll7 respectively
57
DW154 Speclfifatio for Plastics Ductwork
pA XE
B-bliography Included in this Bibliography are technical pUblications which may be of interest (0 ductwork designers fabricators and erectors and to tho e in the heating ventilatlng air conditioning industries generally nquiric should be made of the relevant organisation at the address quoted Since its publication other addresse contained within 0V154 mav have changed and some pubJicalions may have been superseded
HEATING AND VENTILATING CONTRACTORS ASSOCIATION
4 Palace Court London W2 4JG Telephone 020-7229 2488 Fax 020-7727 9268
Orders fo FlY A Publications Old Matlsion House Eamont Bridge Penrith Cumbria CA 10 2BX (Telephone 01768 864771 Fax 01768 86718) Email hvcapoblicationshvwelfarecouk DWn 44 pe ilicatiun for sheet mctal duclwork (Iow- mediulllshy
and high-pressure) 1998) DWIl4 A practical guide to dUGI ork I akage te ting
(revised 2000) DWII54 Specification for plastic~ duct rk DW171 Guide to good Practice for kitchen venlibtion system DW191 Guide to good pracuce glass fibre ductwoJk DwrrMI Acceptance cheme for new products - Redangolar cro
joint classification Guide to good pra tice - Internal cleanliness of new ductwork installations Guide to good practice for the design for the Installation of lire and smoke uampers
J 1Other puhlications
HampV safely guide 5th edition JS2 Tool box talks JS5 Weldlng Safety booklet JSI9 afety facts bo klet Fact sheets 1-24 2nd edition JS2J COSHH manual volume 1 Advice on compliance with the
regulations 1521A CO I-rH manual volume 2 Asses mcnt h ets JS23 Ri k management manual TR3 BrazinltT and bronze welding of copper pipework cUld sheet
(I 976) TR5 Welding of carbon steel pipework (1980)
TR6 Guide to Good Practice for Site Pre sure Testing of Pipework (19 0) Guide to good practice cleanliness of ventilation Ylem
CHARTERED IN TITUTlO OF BUILDING SERVICES E G EERS Delta House 222 Balham High Road London SW12 9BS rTelephone 020-8675 5211 Fax 020-8675 5449) CIBSE Guide Volume A Design Data Volume B In tallatiol1 and quipment Data Volume C Reference Data
CommlssioniJIg Codes These Codes eover the preliminary checkS eUing to work and regulation of vanous catcgories 0 plan The Codes give a guide to design implications Series A Air Distnbution Systems Series B Boiler Plant
ri s C Automatic Conlrol ystems Cr1es R Refrigerating Sy terns
Sene iN Water Distribution Systems
Technkal Memonllda TM 4 Design Notes for the Middle East TM bull Design otes for Ductwork TM 13 Minimi iog lhc Risk of egiounaires Disease
Research Reports RROI95 Ventilation system hygiene - A review of published
infomlatioo on lhe occurrence and ffects of Olltamination Rl~02J95 Air-to-air heal rec v ry RR0395 rnfluen e of HV C on smoke detectors
ATlONAL ENI [ERING SPECIFICATION LfMITED Southgatc hamber 3739 Southgate Street Winchester S023 9EH (Telephone 01962 842058 Fax 01962 R(8982) BUfLDING S RVICES RESEARCH AND [ ORMATION ASSOCIATIO Old Bracknell Lane West Bracknell Berkshire RG 12 4AH (Telephone Brackl1eU (01344) 426511 Fax 01344 487 -7 )
Application Guides AGln4 De tglJing Vana~le Volume middotylans for KOOnl
iir Movement AG1I91 Commissioning of V Sylcms in Buildings 11 6194 Fire Dampers
B) 94 cntiJalion or KitcneTls
AG389 The Commls ionin of Air Systems In Buildmgs AH2192 Commissioning of Bern - A ~ode of Practice TN2417 I Fire Dampec il) Ventilating Ducl
BEATING VENTILATING A AIR CONDITION G MA UFACTURERS ASSOCIATIO (HEVAC) HEVAC Henley Road Medmenham Marlow Buck SU 2ER (Telephone 01491 578674 ox 01491 575024 Emoimiddot infofetacouk)
Publicatjons Air Diffusion Guide Guide to Air Handling Unit Leakage Testing Guide to Good Practice Air Handling Unit Real Room Acoustic ~ st Procedure Specification for the ertiiicatioll ofAir Filters Method of Test for Water Rejection PerfOnTlatce of Louvrcs Subjected 1(1
Simulated Rainfall Test Procedure for Acoustic Loo cs Specification 10 Floor GrilJes - Types Performan e and Method ofTest Specification for the Determination of the Collection Efficiency of SilJ1d
Trap Louvre Domestic Mechwlical Vclltllalion Systems with Heal Recovery Fan Application Guid
~an and Ouctwork Installation Guide Guide to Fan Noise and Vibration
pecification of Requirements for JallJral Smoke and Heal Exhausl Ventilators
pecification for Powered Smoke and Heat Exhaust Ventilators
Specification of Requirements for Smoke Curtains Design Gujue of Smoke Ventilation for Single Storey Lodustrilll Building~
Including those with Mezzanine Floor and IIi Racked Storage Warehou es - Issue 3
Guidance for the Design of Smoke entilation YSlem for Covered and Undergrollnd Car Parks - lssue 1
Application of SOloke Control Equipment and Syst m Guid to Good Practice - Isue J
58
DW154 Sp(C~tiifitiol for Plastics Ductwork
BRITISH STANDARDS INSTIT TION Sales Department 101 P ntooviLle Road London NI 9ND (felephone 020-78 1 78801)
CP 413 1973 Ducts for building ervices
SS 476 Fire tes on building matenals and lruc(ure
Part 4 19 4 Non-combustibility lest or materials
Part 6 I Fire propagation lest for materials
Part 7 1993 Surface spread of tlarnJ tesls for materia
Part 20 1987 Fir resistance of elements of construction
Part 21 1987 Fire r sistlUlce of loadbeanng elements of construction
Part 22 1987 Fhe istallceofllon-loadbearing elemcllts ofconsttuclion Part 23 1987 Contribution of componcnts to the fire resistance 0 a
structure
Part 24t987 Fire resi lance of wl1lilation ductl
SS 5588 nan 919 0 Fire Precautions III thc desIgn and OOSlnJ lion of buildings
S 729 1971 Hot dip galvanized oatiugs (or irOIl aod stcel articles
BS 1449 Steel plate sheet and Irip
Pan 11991 Carbon steel plate heel and strip Part 2 1983 Stainless steel plate sheer and strip
and
B middotENJOI49-2 996 BSEN 10149- 1991)
BSEN 10131 1992
BSEN22063 Sprayed metal coarings 1994 Protection of iron and steel by aluminium and zinc against
atmospheric cOlosion Irotectiotl of iron and ste I against corro ion and oxishydation at elevared temperatures
BS 353 1981 Glossary of lerms relnting to thermal insulation
BS ISO 1479 Self-tapplngscrewsandmetallicdri c crew
B -lSO 7049
1994
B 4800 1989 Painl colour for building purposes B 4848 l0 rolled structural steel sections
Part4 1972 Equal and unequal angles BS 5422 1990 Specification for the use of therm illuating matcriulS
SS 5720 1979 ode of practice for mechanical veutilating and air C 11shy
dirionin bull in building
l3S PR 12814-1 Bend resting for plasric welds
SS PR 12814-2 Tensile testing for plastic welds
SS PR 13067 Appro altesting for plastic welds
BS PR EN I 100-] Vi ual in pection ofplaslic welds
SHEET METAL AND AIR CONDITIONING CONTR-CTORS NATIONAL ASSOCIATION INC (SMACNA) Headquarters 420 I Lafayeue Center Drive Chanlilly Virginia 2051-1209
Mailing Address pa Box 221230 Cbantilly Virginilt120 153-1230
Telephone (703) 803-2980 Fax (703) 803-3732
Accepted IJJdustry Pl3Gtice for Industrial Duct Constnlelion 197 ) i-rchitecmral Sheet kwl Manual ([993)
Comractors Guide lor Modification 10 ooslruerion Colllraets 1993 Ducted Eleclric Heat Guide for ir Handling Ssrerns (1994)
En~rgy ollservatioD Guidelines (1984) Energy Recovery Equipment yslClllS (199l
Fibrou GIns Duct onS1ntClion Standards (1992)
Fire Smoke amp Radiation Damper In tall Guide for HVA Syst ms (1992) Guide t leel Stack 1(95)
HVA Air Duct Leakage Test Manual (19 ) HVA COlllmissioning lvlanual (1994)
H A Duct Construction Standards-Metal amp Flexible (1995) Addendum 01 (Nov 1997)
HVA Duct Systems Inspection Guide (1989)
HVA ySlems-Application (1986) nVAC ByternS-DLlct D ign (1990)
HVi Systems-Testing Adjusting amp Balancing (1993)
indoor Air Quality Manual (1993) tcheu quipment Fabrication Guidelmes (1990)
Managers Guide for elding (1993)
Rectangular Industrial Duct Cons1TUction Standards (19 0) Round Industrial Duct oustmction Standards (1977)
Sei mic Restraint Manual (1991) (wl Appendix E 1993) SMACNA Ma le Index ()fTechnical Publications (1995) Tbennoplnstic Duct CPY ) Construction Manual 1994)
DEPARTME OF THE ENVIRO MENT (Publications Centre) H Stationery Oflice 5 Nine Elms Lane London SWS 5DR
MampEJ 011972 Electrical in tallat1011 in buildings ( ew Editiou)
IampE 0319 Healing hot and cold wat r steam and gas losla1lations for buildings
M amp - No4 1970 Central heating and hot and cold ~ ateT in tallations for
dwelling
M amp ENo100 1971 Mechanical ventilation for building~
ASSOCIATION FOR SPECIALIST FIRE PROTECTlO As ociation House 235 Ash Road AJdershot Hampshire GUl2 4DD
Telephone OJ25221322 Fax 0 J252 333901
lublicalioos Fire Ratcd and moke Outlet Ducrwork An Industry Guide t Design and InSlalla lioll
HEALTH AND SAFETY EXEC TIVE Rose Court 2 Southwark Bridge London SEl 9HS Telephone 020-7717 6000
TWJ THE WELD G TlTUTE Abington Hall Abington Cambridge CB16AL Telepbone 0 J223 89162
Publication DatJ Oil w~ldll1g of lhermopla lics
59
DW154 wciiwlioll for Plastics Ductwork
A -=--DIX
Factors
Specific gravity shy pp = 091 approx UPVC = 14 approx
Some miscellaneous conversion factors
To convert
Length Inches to millimetres Feet to metres
Multiply by
2540 03048
To convert
Millimetres to inches Metres to feet
vIultiply by
003937 3281
Area Square inches to square millimetres 6452 Square millimetres to square inches 000155 Square feet to square metres 00929 Square metres to square feet 10764
Volume Cubic feet to cubic metres Cubic feet to litres Gallons (UK) to litres
002832 2831 4546
Cubic metres to cubic feet Litres to cubic feet Litres to gallons (UK)
35315 00353
022
Mass Ounces to grams Pounds to kiJograms Tons to tonnes
2835 04536
1016
Grams to ounces Kilograms to pounds Tonnes to tons
003527 2205
09842
Volume flow Cubic feet per minute to cubic Cubic metres per second to cubic
metres per second 0000472 feet per minute 2119 Cubic feet per mIDute to litres Litres per second to cubic feet
per second 04719 per minute 2119
Motion Feet per minute to metres per second 000508 Metres per second to feet per minute 197
Pressure Inches water gauge to millibars 2491 Inches wateJ- gauge to pascals (Pa) 2491 I Pa = I ewton per square metre = 10-2 millibars
60
Heating and Ventilating Contractors Association Esca House 34 Palace Court London W2 4JG
Tel 020 7313 4900
e-mail contact Itvcaorguk web site wwwhvcaorguk
Fax 020 7727 9268
DW154 Speclfifatio for Plastics Ductwork
pA XE
B-bliography Included in this Bibliography are technical pUblications which may be of interest (0 ductwork designers fabricators and erectors and to tho e in the heating ventilatlng air conditioning industries generally nquiric should be made of the relevant organisation at the address quoted Since its publication other addresse contained within 0V154 mav have changed and some pubJicalions may have been superseded
HEATING AND VENTILATING CONTRACTORS ASSOCIATION
4 Palace Court London W2 4JG Telephone 020-7229 2488 Fax 020-7727 9268
Orders fo FlY A Publications Old Matlsion House Eamont Bridge Penrith Cumbria CA 10 2BX (Telephone 01768 864771 Fax 01768 86718) Email hvcapoblicationshvwelfarecouk DWn 44 pe ilicatiun for sheet mctal duclwork (Iow- mediulllshy
and high-pressure) 1998) DWIl4 A practical guide to dUGI ork I akage te ting
(revised 2000) DWII54 Specification for plastic~ duct rk DW171 Guide to good Practice for kitchen venlibtion system DW191 Guide to good pracuce glass fibre ductwoJk DwrrMI Acceptance cheme for new products - Redangolar cro
joint classification Guide to good pra tice - Internal cleanliness of new ductwork installations Guide to good practice for the design for the Installation of lire and smoke uampers
J 1Other puhlications
HampV safely guide 5th edition JS2 Tool box talks JS5 Weldlng Safety booklet JSI9 afety facts bo klet Fact sheets 1-24 2nd edition JS2J COSHH manual volume 1 Advice on compliance with the
regulations 1521A CO I-rH manual volume 2 Asses mcnt h ets JS23 Ri k management manual TR3 BrazinltT and bronze welding of copper pipework cUld sheet
(I 976) TR5 Welding of carbon steel pipework (1980)
TR6 Guide to Good Practice for Site Pre sure Testing of Pipework (19 0) Guide to good practice cleanliness of ventilation Ylem
CHARTERED IN TITUTlO OF BUILDING SERVICES E G EERS Delta House 222 Balham High Road London SW12 9BS rTelephone 020-8675 5211 Fax 020-8675 5449) CIBSE Guide Volume A Design Data Volume B In tallatiol1 and quipment Data Volume C Reference Data
CommlssioniJIg Codes These Codes eover the preliminary checkS eUing to work and regulation of vanous catcgories 0 plan The Codes give a guide to design implications Series A Air Distnbution Systems Series B Boiler Plant
ri s C Automatic Conlrol ystems Cr1es R Refrigerating Sy terns
Sene iN Water Distribution Systems
Technkal Memonllda TM 4 Design Notes for the Middle East TM bull Design otes for Ductwork TM 13 Minimi iog lhc Risk of egiounaires Disease
Research Reports RROI95 Ventilation system hygiene - A review of published
infomlatioo on lhe occurrence and ffects of Olltamination Rl~02J95 Air-to-air heal rec v ry RR0395 rnfluen e of HV C on smoke detectors
ATlONAL ENI [ERING SPECIFICATION LfMITED Southgatc hamber 3739 Southgate Street Winchester S023 9EH (Telephone 01962 842058 Fax 01962 R(8982) BUfLDING S RVICES RESEARCH AND [ ORMATION ASSOCIATIO Old Bracknell Lane West Bracknell Berkshire RG 12 4AH (Telephone Brackl1eU (01344) 426511 Fax 01344 487 -7 )
Application Guides AGln4 De tglJing Vana~le Volume middotylans for KOOnl
iir Movement AG1I91 Commissioning of V Sylcms in Buildings 11 6194 Fire Dampers
B) 94 cntiJalion or KitcneTls
AG389 The Commls ionin of Air Systems In Buildmgs AH2192 Commissioning of Bern - A ~ode of Practice TN2417 I Fire Dampec il) Ventilating Ducl
BEATING VENTILATING A AIR CONDITION G MA UFACTURERS ASSOCIATIO (HEVAC) HEVAC Henley Road Medmenham Marlow Buck SU 2ER (Telephone 01491 578674 ox 01491 575024 Emoimiddot infofetacouk)
Publicatjons Air Diffusion Guide Guide to Air Handling Unit Leakage Testing Guide to Good Practice Air Handling Unit Real Room Acoustic ~ st Procedure Specification for the ertiiicatioll ofAir Filters Method of Test for Water Rejection PerfOnTlatce of Louvrcs Subjected 1(1
Simulated Rainfall Test Procedure for Acoustic Loo cs Specification 10 Floor GrilJes - Types Performan e and Method ofTest Specification for the Determination of the Collection Efficiency of SilJ1d
Trap Louvre Domestic Mechwlical Vclltllalion Systems with Heal Recovery Fan Application Guid
~an and Ouctwork Installation Guide Guide to Fan Noise and Vibration
pecification of Requirements for JallJral Smoke and Heal Exhausl Ventilators
pecification for Powered Smoke and Heat Exhaust Ventilators
Specification of Requirements for Smoke Curtains Design Gujue of Smoke Ventilation for Single Storey Lodustrilll Building~
Including those with Mezzanine Floor and IIi Racked Storage Warehou es - Issue 3
Guidance for the Design of Smoke entilation YSlem for Covered and Undergrollnd Car Parks - lssue 1
Application of SOloke Control Equipment and Syst m Guid to Good Practice - Isue J
58
DW154 Sp(C~tiifitiol for Plastics Ductwork
BRITISH STANDARDS INSTIT TION Sales Department 101 P ntooviLle Road London NI 9ND (felephone 020-78 1 78801)
CP 413 1973 Ducts for building ervices
SS 476 Fire tes on building matenals and lruc(ure
Part 4 19 4 Non-combustibility lest or materials
Part 6 I Fire propagation lest for materials
Part 7 1993 Surface spread of tlarnJ tesls for materia
Part 20 1987 Fir resistance of elements of construction
Part 21 1987 Fire r sistlUlce of loadbeanng elements of construction
Part 22 1987 Fhe istallceofllon-loadbearing elemcllts ofconsttuclion Part 23 1987 Contribution of componcnts to the fire resistance 0 a
structure
Part 24t987 Fire resi lance of wl1lilation ductl
SS 5588 nan 919 0 Fire Precautions III thc desIgn and OOSlnJ lion of buildings
S 729 1971 Hot dip galvanized oatiugs (or irOIl aod stcel articles
BS 1449 Steel plate sheet and Irip
Pan 11991 Carbon steel plate heel and strip Part 2 1983 Stainless steel plate sheer and strip
and
B middotENJOI49-2 996 BSEN 10149- 1991)
BSEN 10131 1992
BSEN22063 Sprayed metal coarings 1994 Protection of iron and steel by aluminium and zinc against
atmospheric cOlosion Irotectiotl of iron and ste I against corro ion and oxishydation at elevared temperatures
BS 353 1981 Glossary of lerms relnting to thermal insulation
BS ISO 1479 Self-tapplngscrewsandmetallicdri c crew
B -lSO 7049
1994
B 4800 1989 Painl colour for building purposes B 4848 l0 rolled structural steel sections
Part4 1972 Equal and unequal angles BS 5422 1990 Specification for the use of therm illuating matcriulS
SS 5720 1979 ode of practice for mechanical veutilating and air C 11shy
dirionin bull in building
l3S PR 12814-1 Bend resting for plasric welds
SS PR 12814-2 Tensile testing for plastic welds
SS PR 13067 Appro altesting for plastic welds
BS PR EN I 100-] Vi ual in pection ofplaslic welds
SHEET METAL AND AIR CONDITIONING CONTR-CTORS NATIONAL ASSOCIATION INC (SMACNA) Headquarters 420 I Lafayeue Center Drive Chanlilly Virginia 2051-1209
Mailing Address pa Box 221230 Cbantilly Virginilt120 153-1230
Telephone (703) 803-2980 Fax (703) 803-3732
Accepted IJJdustry Pl3Gtice for Industrial Duct Constnlelion 197 ) i-rchitecmral Sheet kwl Manual ([993)
Comractors Guide lor Modification 10 ooslruerion Colllraets 1993 Ducted Eleclric Heat Guide for ir Handling Ssrerns (1994)
En~rgy ollservatioD Guidelines (1984) Energy Recovery Equipment yslClllS (199l
Fibrou GIns Duct onS1ntClion Standards (1992)
Fire Smoke amp Radiation Damper In tall Guide for HVA Syst ms (1992) Guide t leel Stack 1(95)
HVA Air Duct Leakage Test Manual (19 ) HVA COlllmissioning lvlanual (1994)
H A Duct Construction Standards-Metal amp Flexible (1995) Addendum 01 (Nov 1997)
HVA Duct Systems Inspection Guide (1989)
HVA ySlems-Application (1986) nVAC ByternS-DLlct D ign (1990)
HVi Systems-Testing Adjusting amp Balancing (1993)
indoor Air Quality Manual (1993) tcheu quipment Fabrication Guidelmes (1990)
Managers Guide for elding (1993)
Rectangular Industrial Duct Cons1TUction Standards (19 0) Round Industrial Duct oustmction Standards (1977)
Sei mic Restraint Manual (1991) (wl Appendix E 1993) SMACNA Ma le Index ()fTechnical Publications (1995) Tbennoplnstic Duct CPY ) Construction Manual 1994)
DEPARTME OF THE ENVIRO MENT (Publications Centre) H Stationery Oflice 5 Nine Elms Lane London SWS 5DR
MampEJ 011972 Electrical in tallat1011 in buildings ( ew Editiou)
IampE 0319 Healing hot and cold wat r steam and gas losla1lations for buildings
M amp - No4 1970 Central heating and hot and cold ~ ateT in tallations for
dwelling
M amp ENo100 1971 Mechanical ventilation for building~
ASSOCIATION FOR SPECIALIST FIRE PROTECTlO As ociation House 235 Ash Road AJdershot Hampshire GUl2 4DD
Telephone OJ25221322 Fax 0 J252 333901
lublicalioos Fire Ratcd and moke Outlet Ducrwork An Industry Guide t Design and InSlalla lioll
HEALTH AND SAFETY EXEC TIVE Rose Court 2 Southwark Bridge London SEl 9HS Telephone 020-7717 6000
TWJ THE WELD G TlTUTE Abington Hall Abington Cambridge CB16AL Telepbone 0 J223 89162
Publication DatJ Oil w~ldll1g of lhermopla lics
59
DW154 wciiwlioll for Plastics Ductwork
A -=--DIX
Factors
Specific gravity shy pp = 091 approx UPVC = 14 approx
Some miscellaneous conversion factors
To convert
Length Inches to millimetres Feet to metres
Multiply by
2540 03048
To convert
Millimetres to inches Metres to feet
vIultiply by
003937 3281
Area Square inches to square millimetres 6452 Square millimetres to square inches 000155 Square feet to square metres 00929 Square metres to square feet 10764
Volume Cubic feet to cubic metres Cubic feet to litres Gallons (UK) to litres
002832 2831 4546
Cubic metres to cubic feet Litres to cubic feet Litres to gallons (UK)
35315 00353
022
Mass Ounces to grams Pounds to kiJograms Tons to tonnes
2835 04536
1016
Grams to ounces Kilograms to pounds Tonnes to tons
003527 2205
09842
Volume flow Cubic feet per minute to cubic Cubic metres per second to cubic
metres per second 0000472 feet per minute 2119 Cubic feet per mIDute to litres Litres per second to cubic feet
per second 04719 per minute 2119
Motion Feet per minute to metres per second 000508 Metres per second to feet per minute 197
Pressure Inches water gauge to millibars 2491 Inches wateJ- gauge to pascals (Pa) 2491 I Pa = I ewton per square metre = 10-2 millibars
60
Heating and Ventilating Contractors Association Esca House 34 Palace Court London W2 4JG
Tel 020 7313 4900
e-mail contact Itvcaorguk web site wwwhvcaorguk
Fax 020 7727 9268
DW154 Sp(C~tiifitiol for Plastics Ductwork
BRITISH STANDARDS INSTIT TION Sales Department 101 P ntooviLle Road London NI 9ND (felephone 020-78 1 78801)
CP 413 1973 Ducts for building ervices
SS 476 Fire tes on building matenals and lruc(ure
Part 4 19 4 Non-combustibility lest or materials
Part 6 I Fire propagation lest for materials
Part 7 1993 Surface spread of tlarnJ tesls for materia
Part 20 1987 Fir resistance of elements of construction
Part 21 1987 Fire r sistlUlce of loadbeanng elements of construction
Part 22 1987 Fhe istallceofllon-loadbearing elemcllts ofconsttuclion Part 23 1987 Contribution of componcnts to the fire resistance 0 a
structure
Part 24t987 Fire resi lance of wl1lilation ductl
SS 5588 nan 919 0 Fire Precautions III thc desIgn and OOSlnJ lion of buildings
S 729 1971 Hot dip galvanized oatiugs (or irOIl aod stcel articles
BS 1449 Steel plate sheet and Irip
Pan 11991 Carbon steel plate heel and strip Part 2 1983 Stainless steel plate sheer and strip
and
B middotENJOI49-2 996 BSEN 10149- 1991)
BSEN 10131 1992
BSEN22063 Sprayed metal coarings 1994 Protection of iron and steel by aluminium and zinc against
atmospheric cOlosion Irotectiotl of iron and ste I against corro ion and oxishydation at elevared temperatures
BS 353 1981 Glossary of lerms relnting to thermal insulation
BS ISO 1479 Self-tapplngscrewsandmetallicdri c crew
B -lSO 7049
1994
B 4800 1989 Painl colour for building purposes B 4848 l0 rolled structural steel sections
Part4 1972 Equal and unequal angles BS 5422 1990 Specification for the use of therm illuating matcriulS
SS 5720 1979 ode of practice for mechanical veutilating and air C 11shy
dirionin bull in building
l3S PR 12814-1 Bend resting for plasric welds
SS PR 12814-2 Tensile testing for plastic welds
SS PR 13067 Appro altesting for plastic welds
BS PR EN I 100-] Vi ual in pection ofplaslic welds
SHEET METAL AND AIR CONDITIONING CONTR-CTORS NATIONAL ASSOCIATION INC (SMACNA) Headquarters 420 I Lafayeue Center Drive Chanlilly Virginia 2051-1209
Mailing Address pa Box 221230 Cbantilly Virginilt120 153-1230
Telephone (703) 803-2980 Fax (703) 803-3732
Accepted IJJdustry Pl3Gtice for Industrial Duct Constnlelion 197 ) i-rchitecmral Sheet kwl Manual ([993)
Comractors Guide lor Modification 10 ooslruerion Colllraets 1993 Ducted Eleclric Heat Guide for ir Handling Ssrerns (1994)
En~rgy ollservatioD Guidelines (1984) Energy Recovery Equipment yslClllS (199l
Fibrou GIns Duct onS1ntClion Standards (1992)
Fire Smoke amp Radiation Damper In tall Guide for HVA Syst ms (1992) Guide t leel Stack 1(95)
HVA Air Duct Leakage Test Manual (19 ) HVA COlllmissioning lvlanual (1994)
H A Duct Construction Standards-Metal amp Flexible (1995) Addendum 01 (Nov 1997)
HVA Duct Systems Inspection Guide (1989)
HVA ySlems-Application (1986) nVAC ByternS-DLlct D ign (1990)
HVi Systems-Testing Adjusting amp Balancing (1993)
indoor Air Quality Manual (1993) tcheu quipment Fabrication Guidelmes (1990)
Managers Guide for elding (1993)
Rectangular Industrial Duct Cons1TUction Standards (19 0) Round Industrial Duct oustmction Standards (1977)
Sei mic Restraint Manual (1991) (wl Appendix E 1993) SMACNA Ma le Index ()fTechnical Publications (1995) Tbennoplnstic Duct CPY ) Construction Manual 1994)
DEPARTME OF THE ENVIRO MENT (Publications Centre) H Stationery Oflice 5 Nine Elms Lane London SWS 5DR
MampEJ 011972 Electrical in tallat1011 in buildings ( ew Editiou)
IampE 0319 Healing hot and cold wat r steam and gas losla1lations for buildings
M amp - No4 1970 Central heating and hot and cold ~ ateT in tallations for
dwelling
M amp ENo100 1971 Mechanical ventilation for building~
ASSOCIATION FOR SPECIALIST FIRE PROTECTlO As ociation House 235 Ash Road AJdershot Hampshire GUl2 4DD
Telephone OJ25221322 Fax 0 J252 333901
lublicalioos Fire Ratcd and moke Outlet Ducrwork An Industry Guide t Design and InSlalla lioll
HEALTH AND SAFETY EXEC TIVE Rose Court 2 Southwark Bridge London SEl 9HS Telephone 020-7717 6000
TWJ THE WELD G TlTUTE Abington Hall Abington Cambridge CB16AL Telepbone 0 J223 89162
Publication DatJ Oil w~ldll1g of lhermopla lics
59
DW154 wciiwlioll for Plastics Ductwork
A -=--DIX
Factors
Specific gravity shy pp = 091 approx UPVC = 14 approx
Some miscellaneous conversion factors
To convert
Length Inches to millimetres Feet to metres
Multiply by
2540 03048
To convert
Millimetres to inches Metres to feet
vIultiply by
003937 3281
Area Square inches to square millimetres 6452 Square millimetres to square inches 000155 Square feet to square metres 00929 Square metres to square feet 10764
Volume Cubic feet to cubic metres Cubic feet to litres Gallons (UK) to litres
002832 2831 4546
Cubic metres to cubic feet Litres to cubic feet Litres to gallons (UK)
35315 00353
022
Mass Ounces to grams Pounds to kiJograms Tons to tonnes
2835 04536
1016
Grams to ounces Kilograms to pounds Tonnes to tons
003527 2205
09842
Volume flow Cubic feet per minute to cubic Cubic metres per second to cubic
metres per second 0000472 feet per minute 2119 Cubic feet per mIDute to litres Litres per second to cubic feet
per second 04719 per minute 2119
Motion Feet per minute to metres per second 000508 Metres per second to feet per minute 197
Pressure Inches water gauge to millibars 2491 Inches wateJ- gauge to pascals (Pa) 2491 I Pa = I ewton per square metre = 10-2 millibars
60
Heating and Ventilating Contractors Association Esca House 34 Palace Court London W2 4JG
Tel 020 7313 4900
e-mail contact Itvcaorguk web site wwwhvcaorguk
Fax 020 7727 9268
DW154 wciiwlioll for Plastics Ductwork
A -=--DIX
Factors
Specific gravity shy pp = 091 approx UPVC = 14 approx
Some miscellaneous conversion factors
To convert
Length Inches to millimetres Feet to metres
Multiply by
2540 03048
To convert
Millimetres to inches Metres to feet
vIultiply by
003937 3281
Area Square inches to square millimetres 6452 Square millimetres to square inches 000155 Square feet to square metres 00929 Square metres to square feet 10764
Volume Cubic feet to cubic metres Cubic feet to litres Gallons (UK) to litres
002832 2831 4546
Cubic metres to cubic feet Litres to cubic feet Litres to gallons (UK)
35315 00353
022
Mass Ounces to grams Pounds to kiJograms Tons to tonnes
2835 04536
1016
Grams to ounces Kilograms to pounds Tonnes to tons
003527 2205
09842
Volume flow Cubic feet per minute to cubic Cubic metres per second to cubic
metres per second 0000472 feet per minute 2119 Cubic feet per mIDute to litres Litres per second to cubic feet
per second 04719 per minute 2119
Motion Feet per minute to metres per second 000508 Metres per second to feet per minute 197
Pressure Inches water gauge to millibars 2491 Inches wateJ- gauge to pascals (Pa) 2491 I Pa = I ewton per square metre = 10-2 millibars
60
Heating and Ventilating Contractors Association Esca House 34 Palace Court London W2 4JG
Tel 020 7313 4900
e-mail contact Itvcaorguk web site wwwhvcaorguk
Fax 020 7727 9268
Heating and Ventilating Contractors Association Esca House 34 Palace Court London W2 4JG
Tel 020 7313 4900
e-mail contact Itvcaorguk web site wwwhvcaorguk
Fax 020 7727 9268