bsi 8010 sec 2.1

BS 801 O : Section 2.1 : 1987 UDC 621.644

0 British Standards Institution. No part of this publicalion may be phofocopied or otherwise reproduced without the prior permission in writing of BSI

British Standard Code of practice for

a Pipelines Part 2. Pipelines on land: design, construction and installation

Section 2.1 Ductile iron

Canalisations. Code de bonne pratique Partie 2. Canalisations terrestres: conception, construction e t installation Section 2.1 Fonte ductile

Leitfaden fr Rohrleitungen Teil 2. Landverlegte Rohrleitungen: Bemessung, Bau und Montage Abschnitt 2.1 Rohrleitungen aus Gueisen

British Standards Institution COPYRIGHT British Standards Institute on ERC Specs and StandardsLicensed by Information Handling ServicesCOPYRIGHT British Standards Institute on ERC Specs and StandardsLicensed by Information Handling Services

BSI BS*BOLO P T 2 S E C * 2 - 1 87 W L b Z ' i b b 9 O021848 2 W BS 801 O : Section 2.1 : 1987

Foreword

This Section of BS 8010 has been prepared under the direction of the Civil Engineering and Building Structures Standards Committee. The standard is being published in four Parts to form a complete revision of a l l Parts of CP 2010 as follows.

Part 1 Pipelines on land: general Part 2 Pipelines on land: design, construction and

installation Part 3 Pipelines subsea: design, construction and

installation Part 4 Pipelines on land and subsea: operation and

maintenance The new Part 1 (which will supersede CP 2010 : Part 1 1966) i s intended to contain general information which is relevant to a variety of pipeline construction materials and a variety of transported materials. It deals with those aspects of pipeline development which affect the owner and occupier of land through which the pipeline passes. Part 2 isdivided into several Sections which will be published as separate documents as follows.

Section 2.1 Ductile iron Section 2.2 Steel Section 2.3 Asbestos cement Section 2.4 Prestressed concrete Section 2.5 Glass reinforced thermosetting plastics Section 2.6 Thermoplastics Section 2.7 Precast concrete

Each Section will contain information on the design, construction and installation of a pipeline in the particular material. These Sections will supersede the existing Parts 2, 3,4 and 5 of CP 2010. This Section supersedes CP 2010 : Part 3 : 1972. The content and the t i t l e of the 1972 edition have been changed to refer to ductile iron only, as grey iron is no longer used

as a material for pipelines. By the exclusive use of ductile iron it has been possible to raise the pressure ratings and introduce self-anchoring joints.

Part 3 will include information relevant to the design, instaliation and commissioning of subsea pipelines in steel and other materials. Part 4 will contain advice on the operation and maintenance of pipelines and will probably be in Sections related to the conveyed material. Appendix A describes and illustrates some typical types of joint used with ductile iron pipe. Appendix B gives requirements for non-metallic materials for use with potable water. It has been assumed in the drafting of this British Standard that the execution of i t s provisions is entrusted to appro- priately qualified and experienced people. Attention is drawn to the following principal statutory legislation in the UK. This l i s t i s not intended to be complete and the relevant authorities should be consulted and reference made to Part I. These Acts are supplemented by Statutory Instruments.

Acquisition of Land Act 1981 Control of Pollution Act 1974 Countryside Act 1968 Countryside (Scotland) Acts 1967 and 1981 Gas Acts 1965 and 1972 Land Powers (Defence) Act 1958 Pipelines Act 1962 Public Health Acts 1936 and 1961 Requisitioned Land and War Works Act 1948 Water Acts 1945,1948,1973,1975,1981 and 983 Water (Scotland) Acts 1946,1949,1967 and 1980

Compliance with a British Standard does not of itself confer immunity from legal obligations.

COPYRIGHT British Standards Institute on ERC Specs and StandardsLicensed by Information Handling ServicesCOPYRIGHT British Standards Institute on ERC Specs and StandardsLicensed by Information Handling Services

Contents

Foreword Committees responsible

Code of practice

Subsection one. General

1 Scope 2 Definitions 3 Applications 4 Safety 5 Inspection

Page

Inside front cover Back cover

Page

Subsection six. Construction

24 Trenching 13 25 Pipe inspection, repairs and cutting 13 26 Laying, jointing and anchoring 14 27 Backfilling 14

Subsection seven. Cleaning, testing and commissioning 28 Cleaning 15 29 Testing 15 30 Com mission i ng 16

o

a

Subsection two. Materiais and availability 6 General 7 Pipes 8 Valves 9 Flanges 10 Bolts, nuts and washers 1 1 Gaskets

Subsection three. Design considerations 12 Pipeline design 13 Pipe design 14 Service and environmental considerations 15 Pipelines on supports 16 Access to the pipeline 17 Protective devices and under pressure

connections 18 Joints

Subsection four. Protection against corrosion

19 Pipes and fittings 20 Joints containing steel components

Subsection five. Transport, handling and storage 21 General 22 Transport 23 Handling and storage

3 3 3 3 3 4

5 5 5 8 8

8 9

10 10

1 1 1 1 1 1

Appendices A Types of joint for ductile iron pipelines B Effect of non-metallic materials on water quality C References D Further reading

Tables 1 Maximum hydraulic working pressures, exclusive

of surge, for ductile iron pipes and fittings and flanged joints

ductile iron pipes and fittings and flanged joints 2 Maximum site hydrostatic t e s t pressures for

3 Stacking heights

Figures 1 Push-in joint (type 1) 2 Bolted mechanical joint (type 2) 3 Slip-on coupling (type 3) 4 Flange adapter (type 4) 5 Self-anchoring flange adapter (type 5) 6 Self-anchoring push-in joint (type 6) 7 Self-anchoring tie-bar joint (type 7) 8 Self-anchoring bolted mechanical joint (type 8) 9 Lead-caulked joint (type 9)

10 Flanged joint (type IO)

18 22 22 22

6

7 12

18 18 19 19 20 20 20 21 21 22

1 COPYRIGHT British Standards Institute on ERC Specs and StandardsLicensed by Information Handling ServicesCOPYRIGHT British Standards Institute on ERC Specs and StandardsLicensed by Information Handling Services

BSI BS*&OLO P T 2 S E C m 2 . 1 87 W l b Z 4 b b 7 0023850 O BS 8010 : Section 2.1 : 1987 Code of practice: Subsection one

Subsection one. General

1 Scope This Section of BS 8010 gives design considerations and construction and installation recommendations for ductile iron pipelines and should be read in conjunction with Part I * This British Standard code of practice is not intended to replace or duplicate hydraulic, mechanical or structural design manuals. NOTE 1 . The numbers in square brackets in the text of this Section refer to the numbered references in appendix C. NOTE 2. The t i t les of the publications referred t o in this standard are listed on the inside back cover.

'2 Definitions For the purposes of this Section of BS 8010, the following definitions apply.

2.1 ductile iront. Iron in which graphite is present substantially in spheroidal form, instead of in flakes such as occur in grey iron.

2.2 pipeline. A line of pipes, of any length, without frequent branches. It does not include piping systems such as process plant piping within refineries, factories or treatment plant.

2.3 flexible jointt. A connection between individual pipes and/or fittings that provides angular deflection or axial movement, or a combination of both, in service, without impairing the efficiency of the connection. NOTE. See appendix A.

2.4 rigid joint. A connection that is designed not to permit angular deflection or axial movement in service. NOTE. See appendix A.

2.5 self-anchoring joint. A connection that i s designed to prevent separation under the axial thrust induced by internal pressure, temperature fluctuations or ground movement whilst s t i l l permitting angular deflection and/or axial movement without impairing the efficiency of the joint. NOTE. See appendix A.

2.6 stringing. The placing of pipes in line on the ground ready for laying.

2.7 surge pressure. Pressure that is produced by a change in velocity of the moving fluid. Surge pressure may be positive or negative.

3 Applications The pipelines covered by this Section of BS 8010 are generally suitable for conveying water, sewage, trade waste, slurries, sludges, non-corrosive gases, brine and certain chemicals. Ductile iron pipes are used in distribution systems for natural and town gases and they may also be used in pipelines for the conveyance of these fuel gases

*In preparation. tDefinition repeated from BS 4772 which is currently under revision.

under similar service condil.ms. For limits of pressure adopted by the British Gas Corporation in the United Kingdom and guidance in connection with the installation of ductile iron pipelines for gas, reference may be made to IGE/TD/3 [ I l . When used for the conveyance of sewage, reference should be made to BS 8301 and CP 2005. Ductile iron is suitable for pipelines in locations where ground instability, traffic loading and frost effects present potential hazards and in areas where damage risks are high.

4 Safety 4.1 General The recommendations of this Section of BS 8010 are considered to be adequate for public safety under conditions usually encountered in ductile iron pipelines, including pipelines within towns, cities, water catchments and industrial areas. Attention is called to the need to consider measures to prevent damage or leakage arising from:

(a) corrosive soil conditions; (b) internal corrosion/erosion; (c) external damage by mechanical equipment used on other works; (d) erosion or ground subsidence; (e) any abnormal circumstances.

4.2 Preventative measures Consideration should be given to the use of preventative measures such as the following:

(a) additional external protection (see 19.2); (b) additional internal linings (see 19.3) and/or limitation of flow velocities; (c) provision of increased cover or a concrete cover as a protection against external mechanical damage, or erosion; (d) for serious subsidence, additional flexible joints, anchored joints, rafts or piling; (e) indication of the presence of the pipeline with additional markers particularly in congested areas or areas where future development i s known to be planned, and adequate marking a t river and water course crossings; (f) provision of protection from frost for pipelines above ground or in ducts.

5 Inspection The integrity of a properly designed pipeline depends more on the standards and quality of inspection applied a t a l l stages than on any other single feature. Particular attention should be given to inspection of the pipe and coating before installation for possible damage, of the bedding of the pipeline, jointing and anchoring and to testing. Any sub-standard materials or workmanship detected should be rectified or, where necessary, rejected, before any further work is done.

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BS 8010 : Section 2.1 : 1987 Subsection two

Subsection two. Materials and availability

6 General 8 Valves Ductile iron pipes and fittings should comply with BS 4772. Ductile iron possesses high tensile strength, ductility and resistance to impact fracture, which makes it suitable for the applications referred to in clause 3. I t i s capable of deforming to a significant extent before fracture. All materials should be compatible with the products that are to be conveyed in the pipeline. All materials, including repair materials. likely to come in contact with potable water should be incapable of permitting bacterial growth. Non-metallic materials should comply with the requirements for the effect of non-metallic materials on water quality (see appendix B).

7 Pipes o

7.1 Spigot and socket pipes Ductile iron pipes are manufactured in accordance with BS 4772 in lengths of 5.5 m for DN 80 to DN 800 inclusive and lengths of 8 m for DN 900 to DN 1600 inclusive. A percentage of the pipes supplied may be of shorter length, in accordance with BS 4772. Special arrangements should be made for procuring shorter lengths, where these are considered necessary. External diameters for metric size ductile iron pipes complying with BS 4772 and metric size grey iron pipes complying with BS 4622 are such that the pipes are directly interchangeable. Metric size ductile iron pipes are not directly interchangeable with ductiie or grey iron pipes in imperial sizes and appropriate change fittings should be used in accordance with BS 4772.

7.2 Flanged pipes Flanged ductile iron spun pipes are manufactured by casting the pipe barrel centrifugally and then welding or screwing loose ductile iron flanges on to specially prepared ends. Short lengths are often supplied with integrally cast flanges. The lengths available will vary according to the source of supply. Flanged pipework i s available in sizes DN 80 to DN 1600 inclusive.

@

7.3 Fittings Fittings are generally of the al l socket or flanged type. BS 4772 permits the supply of fittings beyond the specified range in certain aspects, such as:

(a) laying dimensions; (b) pressure rating; (c) permutations of branch/main diameters;

8.1 Control valves Control valves should comply with one of the British Standard specifications listed below.

BS 5150 Cast iron wedge and double disk gate valves for general purposes.

BS 5152 Cast iron globe and globe stop and check valves for general purposes.

BS 5153 Cast iron check valves for general purposes. BS 5155 Specification for butterfiy valves BS 5163 Double flanged cast iron wedge gate valves for

waterworks purposes. Valves outside the range of sizes, or differing in type or otherwise not complying with the specifications listed may be used, provided that they have a t least equal strength and tightness and are capable of withstanding the t e s t requirements of the appropriate specifications and the tests recommended in this Section of BS 8010. A clear indication should be given on al l valves of the direction of rotation needed to close the value (see clause 12).

8.2 Air valves Automatic air valves are available in a number of forms. The most common are single orifice, double orifice and kinetic. Reference should be made to the manufacturer's recommendations.

9 Flanges Dimensional details of flanges designated PN IO, PN 16, PN 25 and PN 40 should comply with BS 4772. These are dimensionally compatible with the corresponding flanges in accordance with BS 4504. Unless otherwise specified by purchaser, PN 16 flanges are supplied for working pressures up to and including 16 bar. BS 4772 permits the use of high tensile steel bolts of smaller diameter than the corresponding low carbon steel bolts, to facil i tate manufacture and installation of larger diameter flanges. Such flanges are marked accordingly. Where high tensile bolts are used with flanges holed for low carbon steel bolts, special washers should be used in accordance with the pipe manufacturer's recommendations. NOTE. Flanges complying with other standards may be supplied against special orders.

IO Bolts, nuts and washers (d) configurations such as angle branches, crosses, etc; (e) joint ends, e.g. socket and spigot bends.

Such fittings are deemed to comply with BS 4772 and are required to be marked as specified in BS 4772.

LOW carbon steel bolts and nuts Should comP!Y with BS 4190 and high tensile steel bolts and nuts should comply with BS 3692, minimum grade 8.8. Washers should

with BS 4320.


B S I BS*8030 P T 2 SEC*2.3 8 7 m Lb24bb7 0023852 4 m BS 801 O : Section 2.1 : 1987 Subsection two

11 Gaskets 11.1 General Elastomeric components of gaskets should comply with the requirements of BS 2494 but other materials may be used if they have been proven to be more suitable. The section of gaskets which is likely to come in contact with potable water, and gasket lubricants, should be incapable of permitting bacterial growth and should comply with the requirements for the effect of materials on water quality (see appendix BI. Where the product conveyed might have a deleterious effect on the gasket, the gasket should be provided with a protective tip of suitable material to isolate it from the contents of the pipeline.

ximum mum temperature limitations apply to the use c both natural and synthetic rubbers. These limitations vary with the type of material used and the design of joints. The manufacturer's advice should be sought if the likely temperature i s below O OC or above 50 OC for mechanical joints or above 60 OC for push-in joints (see appendix A). Gaskets should be protected from unnecessary exposure to the effects of ultra-violet light and ozone. NOTE. Gaskets for flexible joints are frequently referred to as joint rings.

11.2 Flange gaskets The dimensions of gaskets for flanges designated PN IO, PN 16, PN 25 and PN 40 should comply with BS 4865. The use of moulded gaskets designed to suit a range of nominal pressure ratings is permitted.


BSI BS*aO>O P T 2 ~~ SECm2.J - 8 7 ~~- W LbZLthb ~ - - ~ ~ ~~ 002LB53 b ~ W ~~ BS 8010 : Section 2.1 : 1987 Subsection three

Subsection three. Design considerations e 12 Pipeline design The necessary hydraulic, structural and economic assess- ments should be made in accordance with recognized practice [21 and [31. On new installations, consideration should be given to standardizing the direction of rotation needed to close valves as clockwise. A clear indication should be given on a l l valves of the direction of rotation needed to close the valve. The direction of rotation for closure should be the same for any one pipeline installation.

13 Pipe design 13.1 Works hydrostatic test pressure Each pipe and fitting should be subjected to a hydrostatic t e s t a t the manufacturer's works. The pressure is required to be applied steadily and maintained for a period sufficient to facilitate adequate inspection and not less than 15 s. NOTE. Practical considerations limit the works hydrostatic test pressure to values which may be lower than the site test pressure.

13.2 Working pressure Maximum working pressures for classes of pipes and fittings in accordance with BS 4772 are given in table 1.

13.3 Surge pressures The maximum surge pressure should be calculated. It i s essential that the total pressure of the pipeline, including surge, does not exceed the pressure given in table 2. Should it be found that this pressure is likely to be exceeded then protective devices, such as those described in clause 17, should be installed to reduce the actual surge pressure so that the above criterion can be met. a 13.4 Site hydrostatic tes t pressure The site hydrostatic t e s t pressures for ductile iron pipes and fittings and flanged joints in accordance with BS 4772 should be not iess than:

(a) the working pressure + 5 bar; (b) the maximum pressure under surge conditions;

but should not exceed the pressures given in table 2.

1 4 Service and environmental considerations 14.1 General The pipeline internal pressure may be subject to limitations according to the service and environmental conditions in which the pipeline operates.

0 14.2 Pipelines for liquids The internal design pressures for the conveyance of liquids

14.3 Pipelines for gases Where the pipeline conveys a gas and there is, therefore, a considerable amount of energy stored in the compressed gas in the pipeline, operating pressures are restricted, see IGE/TD/3 [Il, Gas operating pressures of the order of 8 bar may be permitted in ductile iron pipelines depending on the type of joint used and the environmental conditions. At these pressures, consideration should be given to the use of self-anchored mechanical joints. NOTE. Such joints provide resfraint within the joint and thus dispense with the need for the traditional form of concrete thrust or anchor block [see appendix A).

14.4 Pipelines for liquids and gases

14.4.1 Vacuum and external fluidpressure. The pipeline should be capable of withstanding a differential pressure brought about by internal vacuum or external fluid pressure (e.g. ground water). Where external pressure exceeds internal pressure by more than 1 bar, the manufacturer's advice should be sought on the choice of joint.

14.4.2 External loading. Ductile iron pipes have adequate strength for a l l normal installations when operating up to the maximum recommended internal pressures for each type of pipe. Where it is necessary to consider the effects of external loads, calculations should be made in accordance with one o f several recognized approaches for computing trench loads, pipe deflection and pipe stress, some of which are listed in appendix D. Consultation with manufacturers should be made where abnormal laying conditions are encountered, e.g. very deep or very shallow with vehicular loading.

14.4.3 Thermal insuiation. Pipelines carrying water that have a depth of cover of at least 0.9 m are not normally subject to freezing in the UK. Where this depth of cover cannot be achieved, adequate thermal insulation should be provided and maintained (see CP 30091 or the system should be designed so that there is always a flow through the pipeline.

14.4.4 Temperature range. The temperature range for ductile iron pipelines is limited to that of the gasket and i s normally O "C to 50 "C or 60 "C as appropriate (see clause clause II). Special elastomeric gaskets are available for the temperature range -10 "C to 120 "C with peaks of up to 130 'C. Gaskets of other materials should be used for temperatures beyond this extended range. Where substantial variations in pipeline temperature may occur, provision should be made for thermal movement. Flexible joints can accommodate normal thermal movement but special installations, such as bridge crossings where the movement may be localized, may require the inclusion of a special expansion joint. Where pipelines are subjected to substantial temperature variations, the effects o f fluid expansion of the internal pressure during shut-down should be taken into account and pressure-relieving devices should be installed, if required.

should not exceed the pressures given in table 1


B S I BS*AOLO P T 2 SEC*Z.L 87 W Lb24bb 0023854 8 W BS 8010 : Section 2.1 : 1987 Subsection three

Table 1. Maximum hydraulic working pressures, exclusive of surge, for ductile iron pipes and fittings and flanged joints"

Nominal size DN

80 1 O0 150 200 250 300 350 400 450 500 600 700 800 900

1 O00 1100 1200 1400 1600

Maximum hydraulic working pressures

Class K9 centrifugally cast pipes. Class K I 2 fittings (including flange pipes with integrally cast flanges)

bart 60 60 60 60 53 47 43 40 38 36 33 31 29 28 27 26 25 25 25

Class K14 fittings (.e. tees) and thicker

bar 60 60 60 50 40 40 25 25 25 25 25 25 25 25 25 25 25 25 25

Flanged joints

PN 10

bar 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10

PN 16

bar 16 16 16 16 16 16 16 16 16 16 16 16 16 16

PN 25

bar 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25

PN 40

bar 40 40 40 40 40 40 40 40 40 40 40

NOTE 1. The maximum hydraulic working pressures of pipes and fittings in other classes will vary from those given in table 1. The manufacturer should be consulted by the purchaser with regard to the production of such pipes and fittings.

NOTE 2. Not al l flexible joints are suitable for the pressures given in table 1 and manufacturers should be consulted for the maximum hydraulic working pressures for particular joint designs. NOTE 3. The maximum hydraulic working pressures given for flanged joints apply to joints in which axial thrusts generated by internal pressure impose tensile stresses to the bolting. Where the bolting o f flanged joints i s not subjected to tensile stresses created by axial thrusts from internal pressure (e.g. flanged valves connected by flanged sockets and flanged spigots in a spigot and socket non-anchored pipeline) the preferred PN 16 flange i s capable of operating a t the pressures given for class K9 centrifugally cast pipe.

NOTE 4. The maximum hydraulic working pressure ratings of flanged pipes and fittings i s the rating of the flange or the rating of the pipe or fitting body, whichever is the lower. NOTE 5. The maximum hydraulic working pressures for pipes and fittings with flanges are applicable in the temperature range -10 O C to 120 O C . The manufacturer should be consulted in connection with maximum hydraulic working pressures for temperatures outside this range and for information in respect of the suitability of specific gasket materials for operating a t particular temperatures. NOTE 6. Internal pressure induces higher stresses in fittings with branches, .e. tees, than in fittings without branches, consequently the maximum hydraulic working pressures for tees in classes K14 and thicker are often lower than for class K I 2 fittings without branches.

'This table i s extracted from BS 4772. t l bar = I O 5 N/m2 = 100 kPa.

6

c


SSIBS*AOLO- ~ ~~ - P T 2 ~ SEC*2-1 ~ _ _ ~ ~ _ _ ~ 87 1b~4667 0021855 -~ -~~~ T = BS 8010 : Section 2.1 : 1987 Subsection three

Table 2. Maximum site hydrostatic test pressures for ductile iron pipes and fittings and flanged joints

Nominal size DN

80 1 O0 150 200 250 300 350 400 450 500 600 700 800 900

1 O00 1100 1200 1400 1600

Maximum site hydrostatic test pressures

Class K 9 centrifugally cast pipes. Class K I 2 fittings (including flange pipes with integrally cast flanges)

bar 65 65 65 65 58 52 48 45 43 41 38 36 34 33 32 31 30 30 30

Class K I 4 fittings (.e. tees) and thicker

bar 65 65 65 55 45 45 30 30 30 30 30 30 30 30 30 30 30 30 30

Flanged joints

PN 10

bar 16 16 16 16 16 16 16 16 i 6 16 16 16 16 16 16 16 16 16 16

PN 16

bar 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25

PN 25

bar 40 40 40 40 40 40 40 40 40 40 40 30 30 30 30 30 30 30 30

PN 40

bar 45 45 45 45 45 45 45 45 45 45 45

NOTE 1. The maximum site hydrostatic t e s t pressures of pipes and fittings in other classes will vary from those given in table 2. The manufacturer should be consulted by the purchaser with regard to the testing o f such pipes and fittings. NOTE2. Not all flexible joints are suitable for the pressures given in table2 and manufacturers should be consulted for the maximum site hydrostatic tes t pressures for particular joint designs. NOTE 3. The maximum site hydrostatic t e s t pressures given for flanged joints apply to joints in which axial thrusts generated by internal pressure impose tensile stresses to the bolting. Where the bolting of flanged joints i s not subjected to tensile stresses created by axial thrusts from internal pressure (e.g. flanged valvesconnected by flanged sockets and flanged spigots in a spigot and socket non-anchored pipeline) the preferred P N 16 flange i s suitable for the test pressures given for class K9 centrifugally cast pipe.

NOTE 4. The maximum site hydrostaficfest pressure of flanged pipes and fittings is the lower of that applicable to the flange or the pipe or fitting body. NOTE 5. The maximum site hydrostatic test pressure for pipes and fittings with flanges are applicable in the temperature range -10 OC t o 120 OC. The manufacturer should be consulted in connection with maximum site hydrostatic t e s t pressures for temperatures outside this range and for information in respect of the suitability of specific gasket materials for operating a t particular temperatures. NOTE 6. Internal pressure induces higher stresses in fittings with branches, .e. tees, than in fittings without branches, consequently the test pressures for tees in classes K14 and thicker are often lower than for class K I 2 fittings without branches. NOTE7. When operating temperatures in excess of 60 "Care expected consideration should be given to carrying out the t e s t a t the operating temperature. NOTE8. Special conditions for gas pipelines are given in 14.3.


ES1 BS*8010 P T 2 S E C * Z * L 8 7 l b 2 4 b b 7 0023856 3 U BS 8010 : Section 2.1 : 1987 Subsection three

15 Pipelines on supports 15.1 General

For pipelines or sections thereof carried on supports, whether above ground, or buried in ground having an inadequate load bearing capacity, the spacing of the supports depends upon the type of joint and the load imposed on the pipeline. Account should be taken of the variation in length of pipes permitted in BS 4772. In al l cases the beam strength and the effect of load concentration at supports should be checked. Adequate anchorage of the pipe to the support should be provided.

15.2 Pipelines on piers above ground

15.2.1 Flexibly jointedpipes. In normal installations where the pipe is required to carry only i t s own mass and contents, one support per pipe, cradling the pipe over a t least 90 o and positioned immediately behind the socket, i s recommended. NOTE. This arrangement allows free articulation of the joint to accommodate temperature movement or settling of the support and ensures that each support carries an equal share of the load.

Where double spigot pipes and coupling are used, twin supports should be provided adjacent to and on each side of the coupling. Where a pipeline is required to span more than one pipe length, e.g. a t stream crossings, special supporting arrangements should be provided to allow a single span of two pipe lengths for socket and spigot pipes. The manufacturer's advice should be sought.

15.2.2 Flangedpipes. In installations where the pipe is required to carry only i t s own mass and contents, the maximum span should be 8 m for sizes up to and including DN 250 and 12 m for sizes DN 300 and above. These spans may be increased in some circumstances, e.g. where the pipeline is working a t less than the rated pressure of the flange or where the pipeline can be designed as a continuous beam. The manufacturer's advice should be sought if increased spans are required. In all cases, the supports should be accurately aligned to ensure that each carries the designed load and cradles the pipe over a t least 90 O .

15.2.3 Pipes carrying superload. The manufacturer's advice should be sought where the pipes are required to carry loads greater than their own mass and contents.

15.3 Pipelines on piers below ground Pipelines laid on piers below ground may be subject to extremely high loads and the manufacturer's advice should be sought. Where buried pipelines are supported on wooden piers, a layer of isolating material, e.g. polyethylene sheet, should be inserted to prevent contact between the pier and the pipeline.

16 Access to the pipeline The design should take full account of the pipeline route and layout and ensure that adequate access i s available to a l l parts of the pipeline. In large diameter pipes, internal access should be provided a t suitable intervals for inspection, maintenance and removal of obstructions and consideration should be given to the need to provide a safe working environment a t all times. Where the use of scraping or swabbing equipment is contemplated, provision for insertion and extraction and the removal of debris should be made a t suitable locations.

17 Protective devices and under pressure connections Protective devices such as relief valves, surge chambers, pressure limiting stations, and automatic shutdown equipment should be provided where necessary, to ensure that the internal pressure a t any point in the pipeline system does not exceed the si te hydrostatic tes t pressure of the pipes used. This is particularly important where any pipeline is connected to another pipeline that is designed for a higher operating pressure.

17.1 In-line valves Valves should be placed in the pipeline a t intervals so that sections of the pipeline can be isolated and emptied, i f necessary, within a reasonable time and without too great a loss of material. At special crossings of major roads, water courses, and railways or other such major points, or in extremely hazardous locations, consideration should be given to the fitting of valves to isolate the section concerned, having due regard to the material being conveyed. Consideration should be given to providing locking arrangements for valves, particularly if butterfly valves are used. Valves should be placed in positions which allow easy access and minimize interference with the use of the land. On larger pipelines in-line valves should be fitted with devices to indicate the degree of opening. Bypass and hydrant arrangements are also recommended for ease of operating and recommissioning sections.

17.2 Air valves Air release valves should be provided between isolating valves on pipelines transporting liquid, for the release and admission of air during filling and emptying of sections of the pipeline and for bleeding off air released by solution during operation of the pipeline. The type of air valve (small single orifice, large single orifice, double orifice or kinetic) should be selected after consideration of the duty and location of the valve and the nature of liquid or gas to be conveyed. Air valves should be located a t a l l topographic high points and a t

.- .. . . . . ... .


high points on the pipeline with respect to the hydraulic gradient, and should also be located a t intervals along any sections where the gradient of the pipeline is parallel to or less than the hydraulic gradient. On long sections of pipeline of even gradient, air valves should be positioned a t intervals of approximately 0.5 km, depending on the diameter of pipeline and the air valve chosen. Air valves may also be required where the gradient o f the pipeline changes. The chamber housing an air valve should be designed to be free draining and free from risk of flooding or possible back siphonage. It i s essential that the chamber housing an air valve i s properly ventilated or provided with an adequate discharge into the atmosphere.

17.3 Drainage valves and washouts Drainage valves should be provided between isolating valves for emptying sections of pipelines transporting liquids and for flushing out the pipeline while in service. Drainage valves on water pipelines should discharge to a watercourse or ditch through a washout pipe, although in urban areas it may be necessary to construct a discharge chamber from which water i s pumped to the surface water drainage system, On sewage pipelines, discharge should be made to a watertight chamber, controlled by a valve a t the end o f the washout pipe or be returned to a convenient gravity foul sewer. The relevant water or drainage authority should be consulted with respect to the allowable size and location of washout discharge. NOTE. The gradient between air release valves and between drainage valves should not normally be less than 1 :250 although in special cases a minimum gradient of 1 :400 may be used.

0

17.4 Under pressure connections These specialized fittings are used to take branches from existing live pipelines. Several designs are available and the particular manufacturer's recommendations should be fol lowed.

18 Joints 18.1 General Flexible joints are of proprietary design and the manufacturer's guidance should be sought regarding interchangeability. The gasket and pipe joint should be in accordance with the manufacturer's dimensions and tolerances. The gasket should be of such size and shape that, when jointed in accordance with the manufacturer's instructions, it provides a positive seal within the manufacturer's range of maximum joint deflection and spigot withdrawal, under al l combinations of joint and gasket dimensional tolerances and in the range of pressures likely to occur along the pipeline including, where applicable, pressures below atmospheric.

18.2 Types of joint

18.2.1 Joint selection. The pipeline should either be designed with sufficient flexibility or be provided with sufficient restraint to prevent thermal movement from causing excessive stresses in the pipes, excessive bending or unusual loads a t joints, and to prevent undesirable forces a t or adjacent to points of connection to equipment or supporting structures, or a t anchors, valves and branches. Account should also be taken of the effects of ground movement. The type of joint to be used should be selected from those described below and illustrated in appendix A.

18.2.2 Flexible non-anchored joints. Flexible non-anchored joints are either of a push-in form (type 1, see appendix A) or a mechanical form (types 2, 3 and 4, see appendix A). Such joints offer l i t t le or no resistance against spigot withdrawai due to internal pressure and dynamic loading and should usually be anchored a t changes of direction and a t blank ends (see 26.3). NOTE. For low pressure gas installations, underground anchorage may not be required.

18.2.3 Flexible self-anchoredjoints, Flexible self-anchored joints are either of the push-in form (types 6 and 7, see appendix A) or mechanical form (type 8, see appendix AI. At changes in direction, blank ends, etc. these joints are an ideal alternative to the traditional concrete anchor block especially in areas where the latter i s undesirable on technical grounds, e.g. very soft ground conditions, remote areas, in busy streets, etc. Careful consideration should be given to the number of anchorage points in order to achieve satisfactory anchorage using self-anchoring joints. It i s rarely satisfactory to anchor the fitting alone since this will only move the point of possible separation further along the pipeline. However, it i s not normally necessary to anchor the entire pipeline and the manufacturer or other expert authority should be consulted to give guidance on the number of joints which need to be anchored. NOTE. Specific recommendations for gas pipelines are given in IGE/TD/3 [ I ] .

18.2.4 Rigid non-anchoredjoints. Where connections are to be made to existing pipelines, which may be in imperial sizes, it may be necessary to use the traditional lead-caulked joint (type 9, see appendix A). This joint allows no deflection or spigot withdrawal and it is essential that it be anchored if there i s any possibility of joint separation.

1 8 2 5 Rigidanchoredjoints. Rigid anchored joints are of the flanged design (type IO, see appendix A). They give no provision for deflection but are self-anchored and, therefore, no external anchorage is required a t changes in direction or a t blank ends. Self-anchoring flange adapters (type 5, see appendix A) obviate the need for external anchorage but offer limited resistance to deflection and should be supported to prevent sag under the mass of the pipe and i t s contents. It i s essential that flanged joints are tightened to a predetermined torque using clean bolts, lubricated on a l l mating surfaces, to ensure that the design load i s obtained. Advice on recommended torques should be obtained from the manufacturer.

I I- \


BSI BS*AOLO P T 2 S E C * 2 * 1 87 M 3624669 0023858 5 BS 8010 : Section 2.1 : 1987 Subsection four

Subsection four. Protection against corrosion

19 Pipes and fittings 19.1 General Pipes should comply with the requirements for corrosion protection specified in BS 4772. In sizes DN 80 to DN 800 the pipes are required to be zinc coated externally prior to bitumen coating internally and externally. For sizes DN 900 to DN 1600 pipes are required to be cement mortar lined and coated externally with bitumen. All fittings are required to be coated internally and externally with a bitumen material. The bitumen to be used should comply with BS 3416 type II or BS 4147 type 1.

19.2 Additional external protection In naturally corrosive soils (usually water-logged heavy clays and saline and peat marshes characterized by an electrical resistivity below 400 i2-m) additional external protection should be provided, e.g. by the correct application of loose polyethylene sleeving as specified in BS 6076. NOTE. Guidance on the correct application of polyethylene sleeving is available from pipe manufacturers and Water Research Centre Information and Guidance Note No, 4-50-01 [41.

In made-up ground containing industrial debris, or in natural soils containing large, sharp-edged stones, shale or flints, the polyethylene sleeving may be liable to mechanical damage during backfilling. Selected backfill should be used to prevent damage to polyethylene sleeving. Where there is a risk of electrical interference currents, or in abnormally corrosive ground, consideration should be

1 .

given to the use a . a more robust protective coat..ig, such as bitumen sheathing or protective tape, alone or with cathodic protection, and advice should be sought from manufacturers or other expert advisory body.

19.3 Additional internal linings Where the contents of the pipeline are conducive to tuberculation, the pipes should be cement mortar lined or protected by other suitable linings.

20 Joints containing steel components Where steel i s used for bolts, nuts and washers, slip-on couplings, or anchorage devices, protection from corrosion should be provided.

Protection can be afforded by packing a suitable mastic material over the components and the adjacent external surface of the pipe so as to form a continuous layer with a smooth profile which can subsequently be wrapped with a compatible cold-applied tape (e.g. petrolatum-based or plastic-backed types, depending on the mastic used). Care should be taken to ensure there are no voids between the mastic and the pipe component substrate, nor between the tape and the mastic. Alternatively, heat-shrinkable sleeves can be obtained for the protection of certain profiles, e.g. flanged joints, bolted flange couplings.


~ BSI BS*8OJO _ _ _ _ _ P T 2 ~~ S E C * 2 9 I ~ 47 W JbZLt-bb7 -- 00238597 -~~ _ _ ~

BS 8010 : Section 2.1 : 1987 Subsection five

Subsection five. Transport, handling and storage O

NOTE. See BS 8010 : Part 1 for procedures to be foliowed before any work is commenced. Pari 1 details procedures and recommendations for work on land which are common to all types o f pipelines.

21 General

Pipes should be loaded and handled with reasonable care in accordance with the manufacturer's recommendations and should not be dropped. Although ductile iron pipes are not susceptible to breakage by impact loading, bad handling can result in damaged coatings or linings and, in severe cases, deformation of the spigot, which could affect the sealing of the joint.

Particular attention should be paid to the following to prevent damage to pipes or joint components:

(a) securing of loads on lorry or wagon;

23.2 Off-loading without crane Where lifting gear i s not available and the mass of the pipe permits (normally DN 250 max.), individual pipes should be off-loaded by rolling them down a ramp formed of timber skids extending from the vehicle side to the ground. During this operation, suitable steadying ropes should be used to prevent the pipes from rolling down at excessive speeds and striking other pipes or objects on the ground.

23.3 Stacking non-bundled pipes

23.3.1 General. Pipes being taken to a central stockground for storage and held pending further distribution should be arranged in stacks. The stacking area should provide a firm foundation with a suitable approach road for vehicles. Stacks should be arranged so as to provide safe vehicular and pedestrian access. During stacking and removal operations, safe access to the top of the stack i s essential. In bad

(b) correct use of suitable handling equipment; weather conditions, when pipe surfaces may become (c) correct stacking methods; (d) proper storage of joint components.

22 Transport

slippery, consideration should be given to the use of lightweight stagings placed on top of the stacks. Pipes should be stacked on a base of raised wooden battens a t least 100 mm thick x 225 mm wide. The battens should be positioned approximately 600 mm from each end of the pipe. The bottom layer of pipes should be securely anchored. Three types of stacking are recommended:

All pipes should be secured to the lorry or railway wagon during transit to prevent movement. The means of securing should be designed to minimize damage to the coating.

(a) square stacking: suitable for pipes including DN 400;

to and

The pipes may-be loaded on to the vehicle in pyramid or straight-sided formation. al l sizes;

When pyramid loaded, the pipes in the bottom layer should be restrained by the use of profiled cradles or broad wooden wedges secured to the vehicle platform. The pyramid should be built by restingthe pipes between pairs of pipes in the preceding layer with t h e sockets in successive layers reversed.

have purpose designed supports along the sides of the vehicle platform or where special cradles separating the layers are used, or where pipes are bundled.

(6) parallel stacking using timber: suitable for pipes of

(c) pyramid stacking: suitable for pipes of al l sizes.

23.3.2 Square stacking. Each tier of pipes should be positioned with their axes a t right angles to those of the preceding tier to form a stable and compact stack. The sockets of the pipes in each tier should be a t the same end, except for the two end pipes which should be reversed

alternate pipes in each tier may be reversed. The pipes rest directly upon those beneath and extra care should be exercised when lowering the pipes into position to prevent damage to the protective coating.

Straight-sided loading should only be used where vehicles to lock the tiers in position. Alternatively, the sockets of

23 Handling and storage 23.1 Off-loadina bv crane - . It is essential that pipe masses, type of stacking, outreach required and site conditions be taken into account when determining the suitability of lifting equipment. The lifting machine should be of the type which retains the load safely in the event of a power failure. Off-loading should be carried out smoothly and without snatch. Where pipes up to and including DN 400 have been bundled, it is essential that the bundles be off-loaded using fork-lifts or cranes with slings around the complete bundle. It is essential that bundles are NOT lifted by means of their retaining straps. When cranes are used for off-loading individual pipes, slings or lifting beams with purpose designed padded hooks should always be used.

23.3.3 Parallel stacking using timbers. For this method of stacking, two timber battens of sufficient strength should be placed across the pipes between each tier, approximately 600 mm from the pipe ends. The sockets of pipes in each successive tier should be reversed and the battens should be of sufficient thickness to avoid metal to metal contact. An adequate number of chocks should be wedged under the outer pipes of each tier and nailed to the timber bearers to ensure stability. NOTE. Pipes may be roiled into position along the battens, thus facilitating stacking or removal from the end of the stack.

23.3.4 Pyramid stacking. In pyramid stacks, each pipe nestles between the two pipes immediately beneath it and care should be exercised when lowering pipes into position. It i s essential that the end pipes of the bottom tier be securely anchored along their length with chocks preferably fixed to timbers running the width of the stack. The axes of all pipes should be in the same direction, and the sockets should be reversed in successive tiers.


BS 8010 : Section 2.1 : 1987 Subsection five

23.3.5 Stacking heights. The heights of stacks should be determined by consideration of:

(a) the stresses on the lowest layer of pipes in the stack;

(b) the total l i ft given by the available crane; and

(c) the facilites available to ensure stable stacking. All these factors should be taken into consideration and the stacking heights should not exceed those in table 3.

be permissible, in such circumstances the manufacturer should be consulted. Care should be exercised when handling such pipes to avoid damaging the protection. They should be lifted by hooks engaging in the socket and spigot ends. The hooks should be as wide as possible and padded with rubber to minimize damage to cement linings. Smaller sizes, up to DN 400, may be lifted with wide fabric slings. Wire ropes or chain slings should not be used.

Table 3. Stacking heights

Nominal size DN

80 1 O0 150 200 250 300 350 and 400 450 and 500 600 700 800 and above

Maximum number of layers in stack

18 16 14 12 10 8 7 6 4 3 2

23.3.6 Pipes having special external protection. Wherever possible, pipes with special external protections should not be stacked but should be laid out in a single layer and supported on the shoulder of the socket and the unprotected spigot end, so that the whole barrel is clear of the ground. If the space available is limited, then reduced stacking may

12

23.4 Stacking bundled pipes

23.4.1 General. The stacking area should provide a firm foundation with a suitable approach road for vehicles. Stacks should be arranged to provide safe vehicular and pedestrian access. Bundles are provided with base timbers and these can be laid directly onto a good, level, hard- standing surface. The bundles should be stacked one on top of the other with the axes of pipes parallel.

The maximum recommended stacking height on a good, level, hard-standing surface is five bundles. However the maximum stacking height for any particular location should be determined by a competent supervisor.

23.4.2 Breaking down ofpipe bundles. I t i s essential that bundles which have been stacked be lowered to ground level before the straps are cut. Special precautions should be taken when cutting the straps of the bundles and when removing pipes from individual tiers. The manufacturer's recommendations should be followed.

23.5 Stringing Pipes should be wedged or pinned to prevent accidental movement. NOTE. See also BS 8010 : Part 1.


Subsection six. Construction

24 Trenching NOTE. See BS 8010 : Part 1 for general considerations regarding trenching.

The width of trench should be as narrow as practicable, taking into consideration the type of native soil and backfill and the compaction equipment required. Where mechanical compaction is required, the width of the trench should be typically pipe 0.d. + 600 mm but may be increased for heavier equipment.

Where mechanical compaction is not required, the width of trench should be typically pipe 0.d. + 300 mm but may be reduced where narrow trenching techniques are employed.

The trench bottom should be prepared to give an even bed for the barrel of the pipe and to ensure proper alignment. The bed should be provided with joint holes to ensure that the pipe rests on the barrel and not on the socket. In rocky ground, the trench should be excavated a t least 100 mm deeper than normally required and then made up to the required level by the addition of well compacted, selected bedding material or imported granular bedding. Where a change in direction is being made by utilizing the lateral deflection available from flexible joints, the trench should be cut to give sufficient room for the joint to be made with the pipes in line, the pipe being deflected after the joint has been made. Deflection of any as-laid joint should not exceed 75 % of the maximum deflection recommended by the manufacturer (see appendix A) to allow for subsequent movement.

25 Pipe inspection, repairs and cutting 25.1 Inspection Ductile iron pipes are not normally susceptible to handling and transport damage but mishandling can damage protective coatings and linings or bruise and deform jointing surfaces and may create ovality. In the case of pipes to be used with a self-anchoring type 8 joint (see appendix A), the presence, a t the spigot end, of the groove for retaining the circlip should be checked.

a

25.2 Repairs of damaged external coatings and linings 25.2.1 Damage to concrete lining or zinc coating should be repaired in accordance with BS 4772.

25.2.2 Coarings and linings. Damage should be made good with a material which i s compatible with the original material and offers equivalent protection.

25.2.3 Special external coatings and linings. Damaged coatings and linings should be made good. The materials and method to be employed wil l depend upon the material originally used and the protection required and should comply with the manufacturer's recommendations.

25.3 Cutting

25.3.1 General. Methods of cutting ductile iron pipes should be selected from the following.

(a) By hand orpower operated hacksaw, using blades having teeth a t a pitch of 1 mm (24 teeth per inch). NOTE. This method is suitable for pipes up to DN 200.

(b] By manually operated wheel cutter, with wheels specifically designed for use with ductile iron. NOTE. This type of cutter is suitable for pipes up to DN 300.

(c) By pipe cutting machine, using cutting tools of the simple lathe or milling saw type. A 7 o front rake is recommended for cutter heads in machines using lathe type cutting tools. NOTE. Pipe cutting machines are available throughout the diameter range and are usually driven mechanically, e.g. by compressed air motor, although for pipes smaller than DN 300 a hand operated windlass may be used.

(d) By power driven abrasive wheel cutting machine, with abrasive discs fitted to suitable hand tools, usually driven by compressed air or small internal combustion engines. It i s important that abrasive disc cutting equipment i s specifically designed for use with ductile iron pipe, that it i s used by a competent operator and that the disc type, size and spindle speed of the equipment are compatible. NOTE. This i s the most widely used method for cutting ductile iron pipes. It has the advantage of being suitable for a l l sizes, with no need for adjustment to suit pipe size or to attach machinery to the pipe.

25.3.2 End preparation of cut pipes forjointing. Any burrs or sharp edges left after cutting should be trimmed off by filing or grinding. Where self-anchored joints of type 8 (see appendix A) are to be used, the cut end of the pipe may be grooved and chamfered on site by means of one of a number of proprietary lightweight cutting machines specially adapted for the purpose. Where joints of type 1 or 6 (see appendix A) are to be used, the cut ends should be chamfered by filing or grinding similar to the original spigot ends. For sizes up to and including DN 300 and for larger sizes where the pipes are marked as being suitable for cutting, the diameter will be within the tape tolerances given in BS 4772, but may be outside the ovality tolerances given in BS 4772. Manufacturer's guidance should be sought as to re-rounding. Other pipes, when cut, may have tape diameters outside the tolerance and these should be ground or machined to the tolerancesgiven in BS 4772. The ground or machined area of spigot projecting out of the socket-face should be coated to give a similar degree of protection as the rest of the pipe, see 25.2.


BSI BSm8OLO P T 2 S E C * E ' * L 87 l b 2 4 b b 7 O023862 7 W BS 8010 : Section 2.1 : 1987 Subsection six

26 Laying, jolliting and ancl roring 26.1 Laying

Pipes should a t a l l times be handled with care in accordance with the manufacturer's recommendations. Pipes should be lowered into the trench with tackle suitable for the mass of the pipes. A mobile crane or a well designed set of shear legs should be used and the positioning of the sling checked, when the pipe is just clear of the ground, to ensure a proper balance. Where lifting equipment i s not available, small diameter pipes (normally DN 250 max.) should be lowered by hand using suitable ropes. All persons should vacate the section of the trench into which the pipe i s being lowered. All construction debris should be cleared from the inside of the pipe either before or just after a joint is made. This can be done by passing a pull-through along the pipe, or by hand, depending on the diameter of the pipe. When laying i s not in progress, a temporary end-closure should be fitted securely to the open end of the pipeline. This may make the pipes buoyant in the event of the trench becoming flooded, in which case the pipes should be held down either by partial re-filling of the trench or by temporary strutting.

26.2 Jointing

26.2.1 General. Jointing procedures will vary according to the type of joint being used. Basic conditions which should be ensured for a l l types of joint are:

(a) cleanliness of a l l parts; (b) correct location of components; (c) centralization of spigot within socket; and

(d) strict compliance with the manufacturer's jointing instructions.

The inside of sockets and the outside of spigots should be cleaned for a t least the insertion depth for each joint. Glands and gaskets should be wiped clean and inspected for damage. Where lifting gear has been used to place the pipe in the trench it should be used to support the pipe and assist in centralizing the spigot in the socket. Where the pipeline i s suspected to be subject to movement due to ground settlement or temperature variation, a suitable gap should be left between the end of the spigot and the bottom of the socket.

26.2.2 Jointingpipes laid ongradients. If pipes are laid on steep gradients where the soil/pipe friction is low, care should be taken to ensure that no excessive spigot entry or

withdrawal occurs. As soon as the joint assembly has been made, the pipe should be held in place and the trench backfilled over the barrel of the pipe.

Unless the gradient is 1 :2 or steeper, anchorages are not normally necessary. However, for these very steep gradients, self-anchoring joints or anchor blocks a t each socket are recommended. For pipelines laid above ground on steep gradients, self- anchoring joints should be used.

26.3 Anchoring Unless an adequate length of the line i s fitted with self- anchoring joints, external anchorage should be provided a t blank ends, bends, tees, tapers and valves to resist the thrust arising from internal pressure and dynamic loading. Anchors and thrust blocks should be designed to withstand the forces resulting from the internal pressure when the pipeline is under test, taking into account the safe bearing pressure of the surrounding soil. Consideration should also be given to forces on the pipeline, when empty, and precautions taken against possible flotation. Where possible, concrete anchor blocks should be of such a shape as to leave the joint area clear.

27 Backfilling NOTE. See BS 8010 : Part 1 for general considerations regarding backfilling, clearing-up and reinstatement.

Wherever possible, in order to minimize misalignment of the bed with resulting shear across the joint, backfill material should not be placed on a pipe until the succeeding pipe is laid and jointed. If joints are are to be individually inspected during hydrostatic testing, it is not practicable to backfill the trench completely. It is important, however, to backfill over the barrel of each pipe and to compact the backfill or take other such measures to prevent movement of pipes during the testing processes. On pipes greater than DN 600 special attention should be given to the compaction of the backfill material under the haunch of the pipe. In most cases tamped, selected excavated material, from the trench will be suitable for the backfill. The material selected for backfill should exclude debris, organic material, frozen soil, large stones, rocks, tree roots or similar large objects. In instances of excessive depths, high vehicular loading or super-loading from buildings, etc. or of very poor soil properties it may be necessary to import backfill (see also 19.2). The manufacturer or other advisory body should be consulted where any doubt exists.

. ..


Subsection seven. Cleaning, testing and commissioning

28 Cleaning Before a pipeline can be considered ready for service it should be cleaned internally as thoroughly as possible to ensure that no foreign matter remains inside the pipe. The first stage of the cleaning operation, .e. cleaning individual pipes during jointing, shouid be performed in accordance with 26.1. Pigs of suitable design, e.g. polyurthane swabs, may be used provided that the pipeline has been constructed to allow the passage of such pigs. Where the pipeline i s to be tested with water, the filling and emptying of the pipeline may to some extent cleanse the line.

29 Testing 29.1 General All pipelines should be tested before being brought into service. The type of t e s t will depend upon the fluid which the pipeline will eventually convey and may be a hydrostatic test or a pneumatic test, or both. The hydrostatic test i s safer to carry out and can be made more stringent as regards the strength of a completed pipeline. It should be used wherever practicable, but it has certain disadvantages when applied to pipelines designed to carry gases. With the exception of testing non-pressure pipelines a t very low pressures (100 mm water gauge), pneumatic testing is to be avoided, if possible, because of the hazards inherent in containing large volumes of compressed air. However, there may be occasions when hydrostatic testing is not possible and air i s the only medium available for applying a t e s t pressure. For pneumatic testing of gas pipelines see 29.3.

29.2 Hydrostatic testing

29.2.1 General- The completed pipeline may be tested either in one length or in sections; the length of section should be decided by considering:

(a) the availability of suitable water; (b) the number of joints to be inspected; and (c) the difference in elevation between one part of the pipeline and another.

Where joints are le f t uncovered until after testing, sufficient material should be backfilled over the centre o f each pipe to prevent movement under the test pressure (see clause 27).

29.2.2 Initialprocedure. It is prudent to begin testing any particular pipeline in comparatively short lengths and to increase the length of tes t section progressively as experience is gained, until lengths of about 1.5 km or more are tested in one section, subject to consideration of the length of trench which it is permissible to leave open in particular circumstances. Each tes t section should be properly sealed off, preferably with special stop ends, designed for the safe introduction and disposal of the test water and release of air, which should be secured by adequate temporary anchors.

The thrust on the stop ends should be calculated on the full spigot external diameter and on the anchors designed to resist it. NOTE. It may often be economical to provide a concrete anchor block which has subsequently to be demolished, rather than risk movement of the stop ends during testing. Hydraulic jacks may be inserted between temporary anchors and stop ends to take up any horizontal movement of the temporary anchors.

All permanent anchors (see 26.3) should be in position and, if of concrete, should have developed adequate strength before testing begins. The section under test should be filled with clean, disinfected water, taking care that al l air i s displaced through vents at high points or by using a pig or a sphere. After filling, the pipeline shouid be left a t working pressure for a period in order to achieve conditions as stable as possible for testing. The length of this period will depend upon many factors, such as movement of the pipeline under pressure, the quantity of air trapped and whether the pipeline has a cement mortar lining which absorbs water. If pressure measurements are not made a t the lowest point of the section, an allowance should be made for the static head between the iowest point and the point a t measurement to ensure that the maximum pressure is not exceeded a t the lowest point.

29.2.3 Test procedure. Site hydrostatic test pressures should be in accordance with 13.4. The pressure in the pipeline should be raised steadily until the si te t e s t pressure i s reached in the lowest part of the section. This pressure should be maintained, by pumping if necessary, for a period of 1 h. The pump should then be disconnected and no further water permitted to enter the pipeline for a period of 1 h. At the end of this period, the original pressure should be restored by pumping and the loss measured by drawing off water from the pipeline until the pressure reached at the end of the test i s reached again. The acceptable loss should be clearly specified and the test should be repeated until this is achieved. The generally accepted loss for non-absorbent pipelines such as steel and iron is 0.02 L/mm of nominal bore per kilometre of pipeline per 24 h per bar of pressure applied head (caiculated as the average head applied to the section under test). The rate of loss should be plotted graphically to show when absorption is substantially complete. A more stringent requirement may be necessary for pipelines carrying fluids other than water.

29.2.4 Detection of leaks. If the t e s t is not satisfactory, the fault should be found and rectified. Consideration should be given to leak detection methods such as:

(a) visual inspection of pipeline, especially each joint, if not covered by the backfill; (b) aural inspection, using a stethoscope or listening stick in contact with the pipeline; (c) use of electronic listening devices including leak noise correlators which detect and amplify the sound of any escaping fluid; actual contact between the probe and the pipe may or may not be essential;

t


BSI BS*8OLO P T 2 SEC*2-L 87 L b 2 4 b b 9 002LBb4 O BS 8010 : Section 2.1 : 1987 Subsection seven

(d) use of a bar probe to detect signs of water in the vicinity of joints, if backfilled;

(e) introduction of a gas compound into the test water, using a gas detection device to detect the presence of any gas that has escaped through the leak.

Where there is difficulty in locating a fault, the section under t e s t should be subdivided and each part tested separately. NOTE. A pneumatic t e s t with an air pressure not exceeding 2 bar may be used to detect leaks in pipelines laid in water-logged ground.

29.2.5 Final procedure. After a l l sections have been jointed together on completion of section testing, a t e s t should be carried out on the complete pipeline in accordance with 29.2.3. During the test, a l l work which has not been subject to sectional tes ts should be inspected.

29.2.6 Disposal of water. It i s important to ensure that proper arrangements are made for the disposal of water from the pipeline after completion of hydrostatic testing and that al l consents which may be required from land owners and occupiers, and from river drainage and water authorities have been obtained. NOTE. With some liquids, notably oil and oil products, it may be necessary to provide temporary interceptors to prevent any oil being discharged with the water. In some cases, e.g. heavily Chlorinated water, some treatment may be necessary before final disposal.

29.3 Pneumatic testing of gas pipelines

29.3.1 General. A pneumatic t e s t should be carried out to prove the tightness of joints rather than the strength of the pipeline. NOTE. The air pressure to be applied will vary according to circumstances.

29.3.2 Safety precautions during pneumatic testing. Pneumatic testing could in the event of failure, give rise to a serious explosion. During each test, it i s important that al l persons not engaged in the t e s t operations be kept away from the section of the pipeline under test.

Persons engaged on pneumatic testing operations should remain in a safe place whilst pressure is being raised and during the whole of the time the pressure i s maintained. No approach should be made for inspection or any other purpose until the pressure has been reduced to the maximum working pressure. I f these precautions are not possible or if hazards to persons and property are likely to arise during pneumatic testing, then a hydrostatictest should be applied first, in accordance with 29.2.

29.3.3 Test procedure. Reference should be made to lGE/TD/3 [ I 1. Ductile iron pipelines for conveying gas should be pneumatically tested a t not less than the maximum gas working pressure. The maximum pneumatic pressure applied should not exceed that specified for any particular jo.int or any other pressure restriction that may be imposed as a result of local conditions or regulations (see 14.3).

29.3.4 Detection of leaks. I f the pneumatic tes t i s not satisfactory the fault should be found and rectified. Consideration should be given to leak detection methods such as:

(a) application of soapy water or similar solution around the joints;

(b) aural inspection using a stethoscope or listening stick; (c) use of electronic listening device; (d) introduction of halogen gas into the pipeline and use of a suitable detector to indicate the presence of gas outside the pipeline; and (e) introduction of a distinctive odorant into the pipeline.

30 Commissioning 30.1 General The procedure for commissioning a completed pipeline will vary according to whether it has been hydrostatically or pneumatically tested and whether it is to convey a liquid or a gas.

30.2 Liquid pipelines Pipelines intended to convey liquids are usually tested hydrostatically and, therefore, commissioning consists of displacing the tes t water from the line by the liquid to be conveyed. Visible dirt and debris should have been removed either manually or by the use of cleaning pigs before testing (see 26.1 and clause 28). Filling and emptying the pipeline with test water may also help cleanse the line. Where air release and drainage valves have been installed, the test water may be drained and the pipeline refilled with the liquid to be conveyed. If the pipeline is intended to carry potable water, it should be thoroughly flushed with clean water, where feasible. It should then bedisinfected by contact for 24 h with water containing a t least 20 mg/L of free chlorine, then emptied and filled with potable water. The chlorinated water should receive treatment to dilute the chlorine to an acceptable level before discharge to sewer or watercourse. After a further 24 h, samples should be taken for bacterio- logical examination at a number of points along the pipeline and a t all extremities. The pipeline should not be brought into service until the water at each sampling point, having stood in the pipeline for 24 h, has maintained a satisfactory potable standard as described in DHSS Report 71 [51.

30.3 Gas pipelines Reference should be made to IGE/TD/3 [ I I . When the pipeline has been subjected to hydrostatic test, the water should be drained from the pipeline. In some cases it may be found convenient to incorporate air release and drainage valves in the construction of the pipeline and to blank off


BSI ~ BS*8LO P T 2 S E C * 2 . 3 87 W L b 2 4 6 6 9 ~ 0 023865 ~~ 2 W ~ ~ ~~ _ _ _ _ _ _ ~ - ~~~ ~ ~c ~ ~- ~~~

BS 8010 : Section 2.1 : 1987 Subsection seven

these fittings after the line has been emptied. Air-propelled swabs may subsequently be used to assist in removing any remai ni ng water. If the pipeline is intended to convey a flammable gas then, when it i s considered to be sufficiently dry, the pipeline should be purged by introducing a slug of inert gas, such as nitrogen. The slug should be of sufficient length to preclude the possibility of the gas to be conveyed coming into contact with the air in the pipeline. The gas to be conveyed should be admitted immediately after the nitrogen slug a t a carefully maintained rate to ensure turbulent flow conditions along the pipeline. The gas should be turned on as the nitrogen is turned off. Proper venting arrangements should be provided a t the end of the pipeline and should consist of:

(a) a vent pipe connected to the pipeline through a valved connection; (b) a small, valved sampling connection;

(c) a pressure gauge connected to the pipeline; and

(d) a suitable detection apparatus to check the change from air to nitrogen and from nitrogen to gas or the change from air to gas where purging i s not required.

For gases that are lighter than air, the vent pipe (see item a) should be vertical and should terminate not less than 2 m above ground level. For gases that are heavier than ait-, the vent pipe should lead to temporary storage where any gashitrogen mixture can be retained and disposed of later. For flammable gases, an efficient flame arresting terminal should be fitted a t the end of the vent pipe. When 100 % gas i s being received either the regulated flow should be closed down and switched to the normal operating route or the pipeline should be closed down ready for use when required. In the latter case, the pipeline should be closed down under a positive pressure which should be monitored regularly until the pipeline i s brought into normal operating service. All temporary connections used during the testing, purging and commissioning procedure should be closed off and securely blanked before the pipeline is brought up to full operating pressure.


BS 8010 : Section 2.1 : 1987 Appendix A

Appendices

Appendix A. Types of joint for ductile iron pipelines

A.0 Introduction Joints are generally of a type using elastomeric gaskets as a sealing medium. The most commonly used types of joint are described in A.l to A.lO. The actual details may differ from one manufacturer to another, The joint deflections stated are the maximum recommended by the manufacturers and are intended to provide for changes in gradient and level, slow curves, the adjustment of angle a t bends and any subsequent movement. Deflection a t installation should not exceed 75 % of the maximum recommended and, where subsequent movement i s anticipated, consideration should be given to further limitation of the installed deflection.

A.1 Push-in joints (type 1) NOTE. See figure 1.

Push-in joints are made on pipes having a chamfered plain spigot a t one end and a specially formed socket a t the other. The seal is effected by means of a gasket placed within the socket before jointing, Entry of the spigot into the socket through this gasket completes the joint. Little effort is required to complete assembly in the case of smaller pipes; tackle to joint larger pipes i s supplied by the manufacturer. Push-in joints are available throughout the pipe diameter range, DN 80 to DN 1600. They can be deflected 5 o in any direction for pipes of diameter up to and including DN 300 and 4 o for pipes of diameter DN 350 and above, and can accommodate considerable axial movement.

L- Figure I . Push-in joint (type I )

A.2 Bolted mechanical joints (type 2) NOTE. See figure 2.

Bolted mechanical joints are made on pipes having a plain spigot a t one end and a specially formed socket a t the other. The spigot i s entered centrally into the socket and the seal i s effected by the compression of a wedge-shaped gasket between a seating on the inside of the socket and the external surface of the spigot. Compression i s achieved by means of a pressure gland and bolts passing through a circumferential flange cast integrally on the face of the socket. Bolted mechanical joints are currently available for pipes in the range DN 80 to DN 600 and al l diameters of fittings DN 80 to DN 1600. The joint may be deflected up to 4 o in any direction and is capable of considerable axial movement.

Figure 2. Bolted mechanical joint (type 2)

A.3 Slip-on couplings (type 3) NOTE. See figure 3.

Slip-on couplings are designed for use with plain end pipes. The coupling consists of a sleeve, a t the ends of which are wedge-shaped rubber gaskets and flanges held together by bolts. Tightening of the bolts compresses the gaskets between the sleeve and pipe to seal the joint. The coupling sleeve may have an internal rib (central register) which acts as a locating stop, but sleeves without this rib are supplied to facilitate the insertion of closing lengths in a pipeline. The coupling includes steel components which should be suitably protected.


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BS 801 O : Section 2.1 : 1987 Appendix A

Slip-on couplings are currently available in the pipe diameter range DN 80 to DN 1600 and special couplings to connect pipes of different diameters and/or materials are available. Several designs are available and the manufacturer's advice regarding deflection and withdrawal should be sought.

Centrai regisfer optional /

/

Figure 3. Slip-on coupling (type 3)

@ AA Flange adapters (type 4) NOTE. See figure 4.

Flange adapters are designed to connect flanged pipe or any flanged fitting to plain-ended pipe. They consist of a flange and sleeve piece, a wedge-shaped rubber gasket and a loose gland fastened to the main body by bolts. Tightening of the bolts compresses the gasket between the sleeve and pipe to seal the joint. The flange joint i s made using standard jointing procedures for flanged pipework. The adapter includes steel components which should be suitably protected. Several designs are available and manufacturers' advice regarding deflection and withdrawal should be sought. Flange adapters do not provide the anchorage and rigidity of a flanged joint and should be supported or anchored accordingly.

A.5 Self-anchoring flange adapters (type 5) NOTE. See figure 5.

Self-anchoring flange adapters are used to connect pipes in the same way as type 10 flanged joints but incorporate special anchor segments. They consist of a loose flange,

Figure 4. Flange adapter (type 4)

bolts and one or more rubber seafs, which carry anchoring segments. Tightening of the bolts seals both the flanges and between the pipe and adapter, and also forces the anchor segments into contact with the pipe. The adapter i s made of ductile iron. Self-anchoring flange adapters are availabfe in the range DN 80 to DN 300. Being self-anchoring they obviate the need for external anchorage but offer limited resistance to deflection and require support to prevent sag under self- weight, the mass of the pipe and i t s contents.

A.6 Self-anchoring push-in joints (type 6) NOTE. See figure 6.

Self-anchoring push-in joints are used to connect pipes in the same way as type 1 push-in joints but have a special gasket. The gasket is of a push-in design in respect of ~ dimensions and shape but stainless steel toothed inserts are moulded into the gaskets. The angle of the teeth i s such that during jointing, the spigot i s able to enter through the gasket unimpeded. When the pipeline is subsequently pressurized, the teeth are firmly presented to the spigot surface and, as the joint tends to separate under the axial thrust induced by the internal pressure, the inserts rotate around the gasket retaining bead in the socket. This causes the teeth to grip onto the spigot surface and prevent joint .separation. The sealing properties are exactly as type 1. The joint i s available in sizes DN 80 to DN 400 inclusive with certain pressure limitations throughout the range. They are capable of being deflected 3 o in any direction and being self anchoring obviate the necessity for anchor blocks a t changes in direction etc. -



A.7 Se. F-anchoring tie- bar joints (type 7)

Anchor segments Pipe seal

\ I

Figure 5. Self-anchoring flange adapter (type 5)

Figure 6. Self-anchoring push-in joint (type 6)

NOTE. See figure 7.

Self-anchoring tie-bar joints are used to connect pipes in the same way as type 1 push-in joints but have a special loose anchor ring placed behind the socket and a special anchor ring welded onto the outer surface of the spigot. The joint offers the same sealing performance as a type 1 joint. The two anchor rings are then locked together using tie-bolts. The joint i s available throughout the diameter range up to and including DN 1600. The joint can be deflected 5 o in any direction for pipes of diameter up to and including DN 300 and 4 o for pipes of diameter DN 350 and above, and can be assembled to permit a controlled amount of axial withdrawal before self-anchoring takes effect. Being self-anchored tie-bar joints obviate the need for anchor blocks a t changes in direction, etc.

i' f Figure 7. Self-anchoring tie-bar joint (type 7 )

A.$ Self-anchoring bolted mechanical joints (type 8) NOTE. See figure 8.

This i s a modified form of the type 2 bolted mechanical joint incorporating a ductile iron circlip which is located in a chamber or groove cast in the socket and which registers with a groove specially machined in the spigot. This joint i s used primarily for gas pipelines a t pressures of up to 8 bar working. IGE/TD/3 [I 1 lays down working pressures and trench conditions where this type of joint should be used in gas pipelines. When the circlip i s fitted, the joint becomes self-anchoring and obviates the use of anchor blocks.


This joint i s available in the range of sizes DN 100 to DN 450 excluding DN 350.

the other. The spigot is entered centrally into the socket o f the adjacent pipe and a quantity of spun yarn compressed

A special tool i s required to dismantle the joint. The joint is capable of 2 o angular deflection in any direction.

into the annulus until this is filled to approximately half the socket depth. Molten lead i s poured into the remaining annulus and, after cooling, is caulked using a suitable tool.

NOTE. For gas pipelines, IGEITDIJ lays down working pressure and trench conditions where this type of joint should be used.

Figure 8. Self-anchoring bolted mechanical joint (type 8)

Fibrous lead may be substituted for molten lead. This joint allows no deflection or spigot withdrawal and it i s essential that it be anchored i f there is any possibility of joint separation.

Lead Yarn Bead on spigot optional

Figure 9. Lead-caulked joint (type 9)

A.9 Lead-caulked joints (type 9) NOTE. See figure 9.

Leadcaulked joints are not recommended for use in new installations. Their use should be restricted to connections

A.l O Flanged joints (type 1 O) NOTE. See figure I O .

Flanged joints are made on pipes by welding, screwing or intearallv casting flanges onto the end of the standard pipe. - .

and repairs to existing pipelines where no suitable alternatives are available. The leadcaulked joints are made on pipes having an enlarged socket at one end and a

The seal i s usual& effected by means of a flat rubber gasket compressed between the flanges by means of bolts which also serve to connect the pipes rigidly. Gaskets of other materials, both metallic and non-metallic, are available for special applications.

or beaded spigot at


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(a) Integral

(b) Welded

(c) Scr

bsi 8010 sec 2.1

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