Voorbeeld - NEN 4 txEN 806-3 3996 Term 3raw-off flow-rate 1 Symbol Unit ixplanation (definitions) QA...

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Ontwerp

NEN-EN 806-3 prEN 806-3

Eisen voor drinkwaterinstallaties in gebouwen. Deel 3: Bepaling van de inwendige middelllijn van leidingen

Publicatie uitsluitend voor commentaar

Specifications for installations inside buildings conveying water for human consumption. Part 3: Pipe sizing

juli 1996 ICS 13.060.10;13.060.20;91.140.60

Commentaar voor 1 december 1996 Zal NEN 1006:1981 en NEN 3048:1967 gedeeltelijk vervangen

De European Committee for Standardization (CEN), waarin de nationale normalisatie-instituten van 18 Europese landen samenwerken, heeft gepubliceerd het Europese normontwerp:

prEN 806-3 Specifications for installations inside buildings conveying water for human consumption. Part 3: Pipe sizing

Definitief vastgestelde Europese normen zullen als Nederlandse norm gelden. Daarom wordt dit normontwerp in

Nederland voor commentaar gepubliceerd. Op het ontwerp ingebracht commentaar zal aan de bevoegde normcom-

missie worden voorgelegd die hiermee rekening zal houden bij de bepaling van de Nederlandse stem. Indien er geen bezwaar bij het NNI wordt ingebracht, kan dat leiden tot ongewijzigd definitieve vaststelling van het ontwerp als norm.

Van Europese normen bestaan drie officiële versies: Engels, Frans, Duits. Voor Nederland zal de Engelse versie gelden, tenzij voor een geautoriseerde versie in het Nederlands wordt gekozen.

Normcommissie 349 099 “Drinkwatervoorziening”

Behoudens uitzondering door de wet gesteld mag zonder schriftelijke toestemming van het Neder- lands Normalisatie-instituut niets uit deze uitgave worden verveelvoudigd en/of openbaar gemaakt door middel van fotokopie, microfilm, opslag in computer- bestanden of anderszins, hetgeen ook van toepassing is op gehele of gedeeltelijke bewerking.

Het Nederlands Normalisatie-instituut is met uitsluiting van ieder ander gerechtigd de door derden verschuldig- de vergoedingen voor verveelvoudiging te innen en/of daartoe in en buiten rechte op te treden, voor zover deze bevoegdheid niet is overgedragen c.q. rechtens toekomt aan de Stichting Reprorecht.

Hoewel bij deze uitgave de uiterste zorg is nagestreefd, kunnen fouten en onvolledigheden niet geheel worden uitgesloten. Het Nederlands Normalisatie-instituut en/of de leden van de commissies aanvaarden derhalve geen enkele aansprakelijkheid, ook niet voor directe of indi- recte schade, ontstaan door of verband houdende met toepassing van door het Nederlands Normalisatie-instituut gepubliceerde uitgaven.

Prijsklasse 48

~ede&ìds ..: Normalisatie-instituut 0 Nederlands 1996

Kalfjeslaan 2, Postbus Normalisatie-instituut 5059,260O GB Delft, Telefoon (015) 2 690 390, Fax (015) 2 690 190

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EUROPEAN STANDARD DRAFT prEN 806-3

NORME EUROPEENNE

EUROPAISCHE NORM July 1996

ICS

Descriptors :

English version

Specifications for installations inside buildings conveying water for human consumption - Part 3: Pipe sizing

Spécifications techniques relatives aux Technische Regeln für Installationen installations d'eau destinée à la innerhalb von Gebäuden für consommation humaine à l'intérieur des Trinkwasser für den menschlichen bâtiments - Partie 3: Calcul des Gebrauch - Teil 3: Ermittlung der diamètres intérieur Rohrinnendurchmesser

This draft European Standard is submitted to the CEN members for CEN enquiry. It has been drawn up by Technical Committee CEN/TC 164 .

If this draft becomes a European Standard, CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration.

This draft European Standard was established by CEN in three official verslons (English, French, German). A version in any other language made by translation under the responsibility of a CEN member into its own language and notified to the Centra1 Secretariat has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom.

CEN

European Committee for Standardization Comité Européen de Normalisation Europäisches Komitee für Normung

Centra1 Secretariat: rue de Stassart 36, B-1050 Brussels

c CEN 1996 Copyright reserved to al1 CEN members

Ref. No. prEN 806-3:1996 E

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prEN 806-3:1996

Contents

Page

Foreword . . . . . . . . . . . . . ..e l . . l . . . . . . . . . . . . . l . . . . . . . . . . . . 3

1 scope ............................................ 3

2 Normative references ................................. 3

3 Concepts, symbols and units ............................ 3

4 Principles of pipe sizing calculations ....................... 5

5 Calculation procedure ................................. 5

6 Flow-rates ......................................... 5 6.1 Determination of flow-rates at the draw-off points ............. 5 6.2 Determination of total flow-rates and allocation to pipework , . , , . . 6 6.3 Determination of design ffow-rates ........................ 7

7 Determination of available pressure for calculation purposes ...... 7

8 Determination of pressura or head losses due to elevation of draw-offs, water meters and other appliances ........................ 7

8.1 Elevation .......................................... 7 8.2 Water meters ....................................... 7 8.3 Mechanica1 filters, softeners, dosing units ................... 8 8.4 Multi-point water heat8rS .............................. 8 8.5 Ether appliances ..................................... 8 8.6 Minimum flow pressure ................................ 8

9 Calculation of pip8 diameter ............................ 9

10 Individual head loss .................................. 10 10.1 Simplified calculation method ........................... 10 10.2 Detailed calculation method ............................. 10

11 Siting of secondary water meters ......................... 14

12 servicepipe.. ...................................... 14

Annex A (normative) Calculation method 1 ..................... 15

Annex 6 (informative) Examples for calculation method 1 ............ 29

Annex C (normative) Calculation method 2 ..................... 40

Annex D (informative) Examples for calcuiation method 2 ............ 46

Annex E (normative) Calculation method 3 .................... 54

Annex F (informative) Examptes for calculation method 3 ............ 63

Annex G (normativs) Calculation method 4 , . . . . . . . . . . . . . . . . . . . . 66

Annex H (normative) Determination of wal1 friction head loss . . . . . . . . 70

Annex 3 (informative) Example for tha determination of water meter head IOSS at design flow-rat8 . . . . . . . . . . . . . . . , , , . , . . . 71

Annex K (informative) Main pressure gradients downstream of boosters . 71

Annex b (informative) . . . . . . . . . . , . . . . . . . . . . . . . . . . . . . . . . . , . . . 72

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prEN 806-3:1996

Foreword

This standard has been prepared under the direction of CEN/TC 164 and is intended for the use of engineers, architects, surveyors, contractors, installem, consumers and inspection authorities (e.g. water works) and should also be of general interest.

NQTE: This standard has been written in the form of a practice specification. ft is the third part of an European Standard consisting of five parts as fellows:

Part 1: Genera1 Part 2: Design Part 3: Pipe sizing Part 4: Installation Part 5: Operation and maintenance

1 Scope

1.1 This standard in conjunction with EN 806-1,806-2,806-4 and 806-5 appiies for the design, installation, modification, maintenance and operation for drinking water installation within premises.

It contains no regulations for fire fighting systems (sec EN 806-2, clause 21). It specifies methods for the determination of pipe si;es which take into account the available supply pressure, the elevation, the number of draw-off points and their required flow-rates and the pipe routing in such a way that an adequate rate of delivery of water without recourse to wasteful oversizing wil1 be provided. Minimum flow-rates Qmin given in table 1 should be available at the hydraulic worst located outlet.

In particular where the reduction of flow could affect the temperature of water delivered to taps and showers, measures to protect the user against excessive temperature changes shall be taken (see EN 806-2, clause f 6).

1.2 The methods of water supply within buildings varies in different European countries. This is often due to justified technical and traditional methods of water supply and also different statutory ! legislative ! regulatory methods.

For the purpose of this part of the standard classifications are included where necessary.

2 Normative references

This European Standard incorporates by dated or undated reference provisions from other publications. These normative references are cited at the appropriate places in the text and the publications are listed hereafter. For dated references, subsequent amendments to or revisions of any of these publications apply to this European Standard only when incorporated in it by amendment or revision. For undated references the latest edition of the publication referred to applies.

prEN 806-1 Specifications for installations inside buildings conveying water for human consumption - Part 1: General

prEN 806-2 Specificationo for installations inside buildings conveying water for human consumption - Part 2: Design

prEN 806-4 Specifications for instatlations inside buildings conveying water for human consumption - Part 4: Installation

ISO 4064-1 Measurement of water flow in closed conduits - meters for cold potable water, specification

3 Concepts, symbols and units

Term 1 Symbol 1 Unit 1 Explanation (definitions)

Design flow-velocity Flow-velocity at design flow-rate

Volume I V I m3 I I Fiow-rate, volume flow t/s

I Q 131 Ratio of the volume of water passing through a speci-

m jh fied flow cross-section and the time required for this I

Minimum flow-rate at draw-off point

I/s Flow-rate at draw-off point which is just sufficient for the appliance to function I

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txEN 806-3 3996

Term

3raw-off flow-rate

1 Symbol Unit ixplanation (definitions)

QA 16s Assumed draw-off flow-rate at appliance for calculation purposes

rotal flow-rate QT VS I: Q,, sum of all draw-off flow-rates of the water appliances supplied

Design flow-rate QD VS Flow-rate for hydraulic calculations, taking into consideration the probable simultaneous demand

static pressure

=low pressure

Minimum f low pressure

PR

PFI

PminFt

Pa Gauge pressure at a measuring point in the water supply system when no water is flowing

Pa Gauge pressure at a measuring point in the water supply system when water is flowing

Pa Gauge pressure required at the connection to a draw- off point at its minimum flow-rate

,owest normal service pressure

Pressure differente, head loss

Head loss as a consequente of differente in elevation

PminS Pa The lowest normal service pressure SPLN means the lowest service pressure at the point of connection occuring during a period of high consumption, as determined by the water supplier

AP Pa Differente in pressure between two points in the drinking water installation

AP* Pa

Available pressure differente Af%l Pa Differential pressure available for wal! friction and individual head loss

Hall friction pressure gradient 8 Pa/m Head loss from wall friction per unit length of pipe

WaI1 friction head loss I l R Pa Head Ioss resulting from wall friction in calculation

Available wall friction pressure gra- R, Pa/m Approximate value used in the calcuiation for the wall dient c friction pressure gradient

tndividual head loss ‘PF Pa Head loss across a water fitting

v2 l p

APF = C l 2-

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??rEN 806-3 : 1996

Term Symbol Unit

Reynotds number Re I

Explanation (definitions)

&2.2 V

Kinematic viscosity

Loading unit

V

LU

m2/s

Factor taking into account the flow-rate required at an appliance, the length of time the appliance is in use and the frequency of use.

4 Principles of pipe sizing calculations

4.1 The principle underlying the design of a drinking water installations the same whether the cold and hot water supplies to sanitary appiiances are obtained from a storage cistern or direct from a main service pipe. Pipe sizing has to include the underground pipes within the premises.

Pipe sizing is based on the loss of head occurring between two points in a section of a pipeline. This is dependent on pipe diameter, length, material and (also on the flow-rate, which is dependent) on the number and sire of the draw-off points connected to the pipe. The draw-off flow-rate required at each draw-off point is the starting point for a determination of the design flow-rate. The simultaneous demand, or the resulting design ftow-rate, for a section of pipe shall be determined on the basis of the methods shown in Annexes A, C, E and G.

4.2 In accordance with basic hydraulic principles the formulae used in calcufations for loss of head resulting from wall friction and flow of water in pipes, used in this standard is given in Annex H. This does not exclude the use of any other suitable formula or procedures subject to the regulations in force in the country in which the installation takes place.

5 Calcuíation procedure

There is no particular “correct” method for siming a drinking water installation pipework.

Examples of calculation methods are given in Annexes 6, D and F.

Depending on the known minimum pressure available in the supply pipe or the location of a cistern in the building, the designer may wish to determine the head losses by a simplified method.

Using this simplified method, head losses included globally as a percentage of wal1 friction, can be applied, for example, to supply systems in residentia buildings but is suitable for all types of supply systems (sec clause 10).

Using the detailed method, head losses due to fittings, bends etc. are calcuiated individually and this ap- proximates more closely the actual service conditions; it provides for the individual fittings resistances to be determined and is also suitable for all types of supply systems.

If the simplified calculation shows that in the worst-case draw-off points cannot be adequately supplied, the need for the provision of boosters is to be checked by means of the detailed method. Each pipe length between pipe junctions should be sized on a trial-and-error basis, starting with the first pipe tength from the source (supply pipe, point of detivery or storage cistern). The residual head at the end of each pipe length should be calculated taking account of head losses in pipework, fittings and valves. If a residual head is arrived at that is negative or less than the head absorbed by the outlet or tap, or if an impracticai pipe size is indicated, the diameter of the preceding pipes should be adjusted and the procedure repeated.

6 Flow-rates

6.1 Determination of flow-rates at the draw-off points

The draw-off flow-rate Q, may be determined as a minimum value (e.g. for flushing valves, taps with flow

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prEN 806-3:1996

control vatves), or as a mean value (e.g. in the cas@ tof mixing va)\pes QT vuashing machines).

Table 1 gives guideline values for the calCujation -flUw-r;Yte of cornmon types of fittings and appliances. ‘6or fittings and appliances not covered in this tabje and where U,, is to ba calcuiated for a given type, determination of Q, shall be based on information provided by the manufacturer, ~ho is to specify the minimum flow-rate at which, with the fitting fully open, proper functioning of the fitting 6r appliance is ensured.

For mixing valves or points of use where hot and cold water is taken through one outlet, 70 96 of the flow-rates given in table 1 may be sufficient when mainly mixed water is drawn; 70 % 0, for the hot and 70 *A QA for the cold water pipe.

Table 1: Draw-off flow-rates QA and minimum draw-off point flow-rates Om,,, at appliances

Appliance

“1 For non domestic machines check with manufacturer

l ‘1 Garden watering, slop sink

6.2 Determination of total flow-rates and allocation to pipework

The draw-off flow-rates for all draw-off fittings should be added together cumulatively, starting at the draw-off point furthest from the source (supply pipe or cistern) and the total flow-rates so obtained assigned to the pipe runs considered. Branch pipes supplying cold water draw-off points and water heaters should be of sufficient capacity to supply the total flow-rate of both hot and cold draw-off points.

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prEN 806-3:1996

6.3 Determination of design flow-rates

The draw-off flow-rate Q, of al1 draw-off points should be included in the design of the water supply system, adding the flow-rate of the draw-off points for which continuous use is to be assumed to the design {simultaneous) flow-rate of the other draw-off points (continuous use being defined as use lasting more than 15 min).

Normally, it may be assumed that not all draw-off fittings are discharging at the same time. Methods for determining the design flow-rate 0, (peak flow-rate at simultaneous demand) at any point in the system could be based on the following:

- Calculation method 1 (see Annex A): This method uses charts showing the design flow-rate for residential- buildings, offices, hotels, hospitals and schools.

- Calculation method 2 (see Annex C): This method uses a system of Loading Units derived from probability theory and takes into acount the flow-rate to the appliance, the length of time of use and the frequency of use..

- Calculation method 3 (see Annex E): This method uses a system of Loading Units derived from probability theory and takes into acount the flow-rate to the appliance, the length of time of use and the frequency of use.

- Calculation method 4 (see Annex G)

7 Determination of available pressure for calculation purposes

7.1 Calculation for the determination of sizes of supply pipes should be based on the pressure resulting from the highth of the cistern or on the lowest normal service pressure specified by the public water supplier, it being the responsibility of the designer to obtain this information. If it is intended to insta11 pressure reducing valves, it is to be ascertained whether these are stil1 required in cases of low service pressure. lf so, the head losses shall be calculated for the pipework downstream of the valve on the basis of that outlet pressure; if pressure reduction is not required at times of low service pressure, the head loss in the pressure reducing vafve, in -its open position, shall be allowed for.

If the lowest normal pressure is insufficient to ensure a suitable water supply, pressure increasing (boosting) systems should be considered (see EN 806-2, clause 18).

Where the water supplier has provided the service pipe, the designer shall enquire from him the flow pressure at the downstream end of the pipe or on point of entry or delivery (see clause 12).

7.2 Calculations for the determination of sizes of distributing pipes should be based on the available head measured vertically from the outlet of the cistern, unless the incoming supply is sufficient to allow a depth of half the cistern of 0,5 m (whichever is less) to be used.

8 Detetmination of pressure or head losses due to elevation of dtaw-offs, water meters and other appliances

8.1 Elevation

For supply pipes, the head loss resulting from differente in elevation ApB is the differente in elevation between the point where pmins is measured and the draw-off point which, in terms of hydraulic engineering, is located at the most unfavourable position (” worst-case point”, for short). For distributing pipes, the head loss resulting from differente in elevation ApB is the differente in leve1 at the draw-off point measured to the leve1 determined in clause 7.2.

8.2 Water meters

Where water meters are installed and the public water supplier specifies the size, the head loss attributable to the water meter or the water meter assembly as stated by the supplier, shall be used in the calculations (see also ISO 4064-1).

The head losses attributable to water meter installation resistances shall be taken into consideration in the determination of the available pressure differente. The head losses corresponding to the design flow-rate for water meters and other associated fittings, resistances (e.g. mechanica1 filters) may be calculated in accordance with the equation (1) as long as a service point (head loss at associated flow-rate e.g. head loss at overload flow-rate for water meter in ISO 4064-1) is given.

MO QO2 =Aps* - as2

(1)

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prEN 806-3:1996

NOTE: The suffix 0 stands for the values at design flow-rate and the suffix S for the given values at a known service point.

The head losses of appliances in the new condition shall be used in the determination of the available pressure. The head losses of the stop valves and backflow prevention devices instalied in the water meter system should be determined in accordance with the loss factors given in table 7. The calculation shall be carried out in accordance with ctause 10, equation 2, or table 8.

The standard values specified in table 2 should be used as the maximum permissible head losses of water meters for instaliation class A. Calculation example see Annex 3.

Table 2: Normal values for head losses in water meters

Water meter types Nomina1 flow-rate Maximum head loss Ap in kPa

QD in m3/h

at Qnlax ( = qs ISO 4064-1)

1 Volumetric, single-jet and multi-jet 1 < 15 I 100 I

1 Vertical Woltman meter, Helix meters t 2 15 I 60 I

1 Parallel Woltman meter, Helix meters 1 2 15 I 30 1

8.3 Mechanica1 filters, softeners, dosing units

The values of the relevant manufacturer’s information have to be taken into account,

for mechanica1 filters where Q,,, equais QD a head loss of 20 kPa (guideline value) may be assumed for installation class A.

8.4 Multi-point water heaters

Table 3: Head losses, multi-point water heaters (only for smatl units)

manufacturers values only

l *) Is equal to switching pressure differential required.

The relevant manufacturer’s information shall be used for appliances not listed in the table.

8.5 Other appliances

Manufacturer’s information should be consulted, For determination of the pressure loss sec equation in clause 8.2.

8.6 Minimum flow pressure

8.6.1 The minimum flow pressure at the worst-case draw-off fitting should be noted.

Guide values for minimum flow pressures are given in table 4.

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prEN 806-3:1996

Table 4: Guide values for minimum flow pressures

Appliance MinimumiJlkp”a pressure

for high pressure taps I for IOW pressure taps

I WC-cistern I 50 I 10

I DN 20 flush vaive I 120 I

I Urinal flush vake 1 100 I 10

I ~~~~ Hand basin ordinary clraw-off I 100 I 10

r Washbasin taps or mixers Washbasin spray tap

10 10

I Bath domestic I 100 1 10

I Bath non domestic I 100 1 10

I Shower head I 100 1 I Domestic kitchen sink I 100 1 10

1 Non domestic kitchen sink DN 20 1 100 I 10

1 Non domestic kitchen sink DN 25 1 100 I 10

I Domestic washing machine* 1 1 100 I depending on type

I Domestic dish washing machine’) I 100 I depending on type

Taps without aerators DN 15 50 10 without aerators DN 20 50 10

‘) non domestic, check with manufacturer ,

8.6.2 Dtaw-off taps

The residual head available at each tap should be at least equal to the minimum flow pressure at the design flow-rate. Alternatively, the loss of head may be expressed as an equivalent length of pipe (see Annex C).Guide values for minimum flow pressures taps are given in table 4.

8.6.3 Float-operated valves

The nomina1 size of a flost-operated valve, the diameter of its orifice and the size of float required are all dependent on the minimum flow pressure at the inlet to the valve and the flow required. The relationship between discharge, size of vake, orifice and head loss is shown in clause 10.2 and Annex C.2. Where non- standard float valves are used, the data relating the flow rate to the head of water available at the inlet should be obtained from the manufacturer. .

9 Calculation of pipe diameter

For tables for wal/ friction head loss national recommendations shall be followed. Calculation of wall friction head loss see Annex t-l.

Suitable pipe diameter can be determined by scheduling the following information shown in table 5 (e.g. tables B.4 and B.5) or diagram (e.g. figure 0.3); suitable specimen forms for calculations are shown in Annex L.

- draw-off flow-rate Q,,

- the wall friction pressure gradient R,

- the design flow-velocity vD,

- the internal diameter d or nomina1 diameter DN.

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prEN 806-3:1996

Table 5: Specimen for wall friction pres~sure gradknt R and design flow-velocity vg as 3 functiofi 0J Xh3sign lfiow~-raf+9 U, for “pip43 material”

in m/s

Tables and diagrams for the wal1 friction pressure gradient R should be based on the condition of the temperatu- res of 10 ‘C and 70 l C.

When the pipe sizes are selected, it shall be established that the maximum design flow-velocities for a given pipe run (at design flow-rates) are not exceeded (sec table 6).

Table 6: Maximum design flow-velocity for a given pipe

. Type of pipe run

Velocity range 1 maximum design flow-

velocity in m/s for flow lasting

5 15min > 15 min

Velocity range 2 ” ” l 1 Velocity maximum design flow-velocity range 3

in m/s maximum for hot water temperature ex- design

ceeding f low-veloci- w

50’ 70’ in m/s

Service pipes 2 2

Supply and distributing pi- 3 2,5 2 ws

Pipe runs with: low head loss in-line valves i.e. less than 2,5”) 5 2 2

in-line valves with greater 23 2 2 toss factor l l ) \

Hot water circulation pipes 0,7 0,7

‘) e. g. piston type gate valve, hall valves, oblique pattern globe valves (of DN 20 or morel.

‘*) e. g. straight pattern globe valves.

* “1 These maxima do not apply to smal1 bore connections of limited length supplied as parts of draw-off taps etc.

10 individual head loss

10.1 Simplif ied calculation method

In this method the individual head losses due to fittings, valves etc.are not individually assessed. Instead a global percentage of wal1 friction is assumed. Experience shows a value of between 10 % and 50 *16 is often needed, but the actual figure will depend on the experience of the designer e.g. for residental buildings between 40 % and 60 %. Simplified method of determination of sites of floor service pipes is shown for design flow-rate method 1 in Annex A.2.

10.2 Detailed calculation method

The pipe sizes calculated with a percentage deduction for head loss due to fittings head loss may serve as a criterion for deciding whether the detailed method is to be applied.

The total head loss in the pipework system (except for losses in appliances) is the sum of the pipe individual head loss and the head loss due to wal1 friction.

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€ 47.60__ ex. NEN-EN 806-3:1996 Ontw. en Eisen voor drinkwaterinstallaties in

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