bs-6464-1984-reinforced-plastics-pipes-fittings-and-joints-for-process-plants.pdf

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BRITISH STANDARD BS 6464:1984Incorporating Amendment No. 1

Specification for

Reinforced plastics

pipes, fittings and

joints for process plants

UDC 621.643.2:678.067.5:66.026


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BS 6464:1984

This British Standard, havingbeen prepared under thedirection of the PlasticsStandards Committee, waspublished under the authorityof the Board of BSI and comesinto effect on28 September 1984

© BSI 03-1999

The following BSI referencesrelate to the work on thisstandard:

Committee reference PLM/9

Draft for comment 76/50861 DC

ISBN 0 580 13776 7

Committees responsible for thisBritish Standard

The preparation of this British Standard was entrusted by the Plastics

Standards Committee (PLM/-) to Technical Committee PLM/9 upon which thefollowing bodies were represented:

British Chemical Distributors’ and Traders’ Association Ltd.

British Gas Corporation

British Plastics Federation

British Steel Industry

British Valve Manufacturers’ Association Ltd.

Copper Tube Fittings Manufacturers’ Association

Department of the Environment (Housing and Construction)

Department of the Environment (PSA)

Electricity Supply Industry in England and Wales

Engineering Equipment and Materials Users’ Association

Institution of Civil Engineers

Institution of Municipal Engineers

Institution of Public Health Engineers

Institution of Water Engineers and Scientists

National Association of Plumbing, Heating and Mechanical Services Contractors

Plastics and Rubber Institute

Plastics Land Drainage Manufacturers’ Association

Royal Institute of Public Health and Hygiene

STC Water Regulations and Fittings Scheme

Water Companies Association

Water Research Centre

The following bodies were also represented in the drafting of the standard,through subcommittees and panels:

British Adhesive Manufacturers’ Association

British Board of AgrémentGreater London Council

Heating and Ventilating Contractors’ Association

Institute of Plumbing

Ministry of Agriculture, Fisheries and Food

Pitch Fibre Pipe Association of Great Britain

Amendments issued since publication

Amd. No. Date Comments

6294 November1990

Indicated by a sideline in the margin


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BS 6464:1984

© BSI 03-1999 i

Contents

Page

Committees responsible Inside front cover

Foreword iiiSection 1. General

1 Scope 1

2 Definitions 1

3 Nomenclature, symbols and units for design 1

Section 2. Materials and properties

4 Thermosetting resin systems 2

5 Fibrous reinforcement 2

6 Aggregates and fillers 2

7 Thermoplastics liners 2

8 Cement for bonding spigot and socket joints 2

9 Mechanical properties 310 Thermal properties 3

11 Chemical properties 4

12 Construction of a chemical liner 4

13 Flammability 4

Section 3. Design and design calculations

14 General 5

15 Laminate design and thickness 6

16 Design calculations for pipes subject to internal pressure 7

17 Design calculations for pipes subject to vacuum 7

Section 4. Dimension markings and information

18 Dimensions 819 Tolerances on dimensions of pipes and fittings 9

20 Marking 9

21 Information 9

Section 5. Construction and workmanship

22 Manufacturing conditions in works involving the cure of resins 10

23 Manufacturing procedure 10

24 Thermoplastics liners 10

25 Fittings 11

26 Joints 15

Section 6. Testing

27 Tests for design 1828 Production testing 19

29 Welding procedure tests for thermoplastics linings 20

30 Tests for production welds in thermoplastics linings 20

31 Production samples for mechanical tests on a laminate 20

Section 7. Inspection and testing

32 Facilities for inspection and testing 20

33 Certification of inspection and testing 20

Appendix A Information to be given with an enquiry or tender or onreceipt of an order 22

Appendix B Methods of test 22

Appendix C Worked examples of the design method specified in section 3 28 Appendix D Methods of manufacture of reinforced plastics pipes 34

Appendix E Acceptable limits of visual defects 35


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BS 6464:1984

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Page

Appendix F Pipework fabrication methods 36

Figure 1 — Limits of pressure and diameter 37Figure 2 — Relationship between thickness and glass content forlaminates with resin of relative density, (+), 1.1 to 1.3 38

Figure 3 — Relationship of unit modulus to winding angle 39

Figure 4 — Factor related to temperature 39

Figure 5 — Factor related to cyclic loading 40

Figure 6 — Butt joint build-up for lined pipe 41

Figure 7 — Pipework shapes for fabrication methods 1 and 2 42

Figure 8 — Flanged pipe fittings for method 3 43

Figure 9 — Typical stub flanges (type A) 44

Figure 10 — Typical full faced flanges (types B and C) 45

Figure 11 — Butt joint build-up for unlined pipe 46Figure 12 — Test piece for the determination of shear strengthof bond between thermoplastics lining and laminate 46

Figure 13 — Test piece for the determination of lap shearstrength of laminate 47

Figure 14 — Test for the determination of peel strength ofbond between thermoplastics liner and laminate 48

Figure 15 — Test piece for the tensile strength of thermoplasticssheet and welds 49

Figure 16 — Typical examples of laminate construction 50

Figure 17 — Biaxial failure envelope 51

Table 1 — Derivation of definitions relating to symbols 3

Table 2 — Minimum mechanical properties of reinforcedlaminate layers 4

Table 3 — Factors to be applied to design unit load of continuousrovings for different winding angles 3

Table 4 — Factor relating to method of manufacture 5

Table 5 — Factor relating to loss in ultimate tensile strength 6

Table 6 — Minimum socket depths 12

Table 7 — Equations for calculating fittings dimensions 13

Table 8 — Minimum separation dimensions to be usedin equations of Table 7 13

Table 9 — Dimensions of flanges 14

Table 10 — Thickness and mating dimensions of flangesand backing flanges 15

Table 11 — Minimum butt joint overlay lengths including taper 17

Table 12 — Acceptable limits of visual defects 35

Table 13 — Pipework fabrication methods 36

Publications referred to Inside back cover


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BS 6464:1984

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Foreword

This British Standard has been prepared under the direction of the PlasticsStandards Committee. Its purpose is to establish a general standard for the

design and manufacture of reinforced plastics pipes and fittings for process plant.The manufacture of pipes and fittings in reinforced plastics involves a number ofmaterials, plastics and reinforcing systems and a number of different methods ofmanufacture.

Metallic pipes, being made from materials which are isotropic, may convenientlybe designed by calculating permissible stresses, based on measured tensile andductile properties. Reinforced plastics are usually anisotropic, and the designmethod adopted in this standard, being based on unit loading, is particularlysuited to the design of composite materials.

This standard includes a method of calculation for an appropriate laminateconstruction based on the allowable unit loading and unit modulus for the type ofcomposite concerned. Design factors are included to cover such variables as:

a) deterioration of the composite properties over a long period;b) effect of temperature on the properties of the composite;

c) repeated or alternating loading.

The nominal pipe sizes specified in this standard have been selected from thoseunder consideration within Technical Committee 138, Plastics pipes and fittingsfor the transport of fluids, of the International Organization for Standardization(ISO).

It is implicit that pipes and fittings covered by this standard should be made onlyby manufacturers and operators (see 23.1 and 24.4) who are competent andsuitably equipped to fulfil all the requirements of this standard.

It is expected that these principles will be proved by documentation of pastexperience or by prototype testing, being supplied to the satisfaction of the

purchaser or the nominated inspecting authority as appropriate.

Attention is drawn to BS 5480 which covers pressure and non-pressure GRPpipes, joints and fittings intended for conveying, above or below ground, liquidsincluding potable and non-potable water, foul sewage and storm water.

The following publications give information on stress/strain analysis of laminates(see clause 9 and 15.1).

Jones, R M, “Mechanics of composite materials”, McGraw Hill (1975)

Calcote, L R, “The analysis of laminate composite structures”,van Nostsand (1969)

Eckold, G C, Leadbetter, D, Soden, P D, and Griggs, P R, “Lamination theory inthe production of pipeline envelopes for filament wound materials subject tobiaxial loading”, Composites (1978)

A British Standard does not purport to include all the necessary provisions of acontract. Users of British Standards are responsible for their correct application.

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

Summary of pages

This document comprises a front cover, an inside front cover, pages i to iv,pages 1 to 52, an inside back cover and a back cover.

This standard has been updated (see copyright date) and may have hadamendments incorporated. This will be indicated in the amendment table onthe inside front cover.


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iv blank


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Section 1. General

1 ScopeThis British Standard specifies requirements for thematerials, properties, design calculations,manufacture, inspection and testing of reinforcedplastics pipes, fittings and joints consisting ofthermosetting resin systems with glass fibrereinforcement (GRP) for process plants.Constructions both with and without a lining ofthermoplastics are included. The information to besupplied for designs for pipes and fittings to thisstandard is given in Appendix A.

This British Standard is not applicable in the

following circumstances:a) where the product of the design pressure inbar1) and the nominal diameter in millimetres ismore than 11 000 (see Figure 1);

b) where the operating temperature is outside thelimits of – 10 °C to + 110 °C;

c) where the pipes may be subject to some appliedexternal pressure other than that due to soilloading or vacuum;

d) where there is a non-taint requirement, e.g. forthe water and food industries, as no requirementsare given for the effect of GRP on those materials.

NOTE 1 In addition to the specific exclusions above, thefollowing points are emphasized and it should not be assumedthat pipes made in accordance with this standard will necessarilybe universally suitable for chemical plant use.

1) Unstressed dip coupon testing of sample laminates may notnecessarily give a valid indication of the long term resistanceof the material to the actual internal and external chemicalenvironment.

2) Relatively small changes in the concentration of organicsolvents and fluctuations in the operating temperatures canhave marked effect on the chemical resistance of a GRPlaminate.

3) Most of the practical experience and design data on whichthis standard is based relates to pipes which were made by thehand lay-up process and contained large proportions ofchopped strand mat reinforcement, and most of the practical

experience under operating conditions was obtained withsmall diameter pipes which were only subject to low positivepressure.

4) In many chemical plants pipework may be subject tooccasional applied loads or impacts, which are not a part of thenormal operating conditions. Care should be taken wheresuch hazards are liable to arise.

It is recommended therefore that manufacturers ofGRP pipes should demonstrate their ability toproduce satisfactory pipe and fittings for anyspecific duty, either by producing documentaryevidence of past performance under similarconditions or by making and testing prototype units.

NOTE 2 The titles of the publications referred to in thisstandard are listed on the inside back cover.

2 Definitions

For the purpose of this British Standard the

definitions given in BS 1755-1 apply, together withthe following.

2.1curing2)

the chemical reaction resulting in the finalpolymerized product

NOTE It may be effected at ambient temperature or by the useof heat. In certain resin systems the full cure has to be effected intwo stages of which the first may, and the second does, involvethe application of heat. This second stage is known as the“post-cure”.

2.2

laminate

2)

a resin reinforced with a form of glass fibre material

2.3laying-up2)

a process of applying or producing laminates inposition on a former prior to cure

2.4aggregates

an inert granular material of a size rangebetween 5 mm and 0.05 mm used as a design part ofthe structure

NOTE Aggregates, such as silica sands, may be incorporatedwhere they are a design part of the composite structure.

2.5inert fillers

a fine material with a particle size below 0.05 mm

2.6angle of lay, Ú

the angle of the application of continuous rovingswith respect to the horizontal axis

3 Nomenclature, symbols and units fordesign

Several terms relating to the strength and loadcarrying capacity of individual layers of compositelaminate are used in this standard. Some havesimilar but quite distinct meanings and because oftheir similarity and their application, particularcare is required in their use. The terms concernedare listed in Table 1, with their definitions, symbolsand units.

1) 1 bar = 105 N/m2 = 100 kPa.2) These definitions differ from those given in BS 1755-1.


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The following additional symbols with their termsare used in the design calculations:

Section 2. Materials and properties

4 Thermosetting resin systems

NOTE 1 The thermosetting resins used for the manufacture ofpipes and fittings may be of a number of types. There are manyresin systems in each type and the properties of these systemsvary, especially with respect to chemical resistance and heatdistortion point.

Polyester and epoxy resin systems shall comply withBS 3532 and BS 3534 respectively.

In order for the chemical reaction, resulting in thefinal polymerized product, to take place hardeners,catalysts and accelerators shall be added to theresin in accordance with the manufacturer’srecommendations.

NOTE 2 The amount of hardener, catalyst and/or acceleratorused is critical, as it can affect both the rate of reaction and extentof the cure.

NOTE 3 If specified at the placement of an order, the outerlayer of resin may incorporate pigments, dyes or specificultraviolet light absorbers to prevent the transmission of UVlight and/or for identification purposes.

5 Fibrous reinforcement

The glass fibre reinforcement used in the body of the

laminate shall comply with BS 3396, BS 3496,BS 3691 or BS 3749, as appropriate, and shall havea surface treatment compatible with the resin.

6 Aggregates and fillers

The resin used shall contain only fillers as requiredfor viscosity control; they shall be limited to amaximum of 5 % of the mass of the resin and shallnot interfere with the capability to visually inspectthe laminate.

Special additives, such as aggregates, graphite andfire retardants, etc., shall only be used to impart

special properties, e.g. stiffness, conductivity.

7 Thermoplastics liners

If thermoplastics liners are used, the material shallbe selected on the basis of resistance to the fluid tobe carried.

If unplasticized polyvinyl chloride (uPVC) is thespecified liner, uPVC pipe complying with BS 3505or BS 3506 shall be used. In the case of nominalsizes greater than 500 mm uPVC sheet complyingwith BS 3757 shall be used for fabrication(see clause 24).

The minimum thickness for uPVC shall be 2.5 mm.If used, the minimum thickness of polypropyleneshall be 2 mm except for pipe of diameter 80 mm orless, for which the minimum thickness shallbe 1.5 mm.

NOTE Specialized liners such as CPVC, FEP, PVDF and PTFEmay be required for very difficult process conditions.

8 Cement for bonding spigot andsocket joints

The manufacturer shall ensure that the bondingcement will be satisfactory for the chemical

conditions specified, and shall state the minimumambient conditions required for the bonding systemto cure properly.

The bonding cement shall develop a minimuminternal shear strength of 7 N/mm2, when tested inaccordance with the method described in B.2.

When tested in accordance with the methoddescribed in BS 5350-C5, using double overlapped joint test pieces, bond materials to be used to joinGRP sockets and spigots shall have a minimumbond strength of 7 N/mm2.

K overall design factor determined from theequation (1),

k1 factor relating to method of manufacture,

k2 factor relating to long term behaviour,

k3 factor relating to temperature,

k4 factor relating to cyclic loading,

k5 factor relating to curing procedure,

nx number of layers of type x in constructionunder consideration,

mx mass of reinforcement per unitarea (kg/m2 glass) in one layer of type x,

ux design unit loading[N/mm {per kg/m2 glass}] for a selectedlayer of type x,

X x unit modulus of a selected layer of type x[N/mm {per kg/m2 glass}]

ºx allowable strain for each type of reinforcingmaterial,

º allowable strain, determined from resinproperties,

ºd maximum design strain,

ºR strain to failure of the unreinforced resindetermined by the method described in

Method 320C of BS 2782:Method 320 A toF:1976.


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Table 2 — Minimum mechanical properties of reinforced laminate layers

11 Chemical properties

NOTE 1 The chemical resistance of resins varies with the type,the source and the state of cure.

In the absence of case histories, the suitability of alaminate for a particular duty shall be establishedby tests carried out in accordance with the methodsdescribed in BS 4618-4.1. The test pieces shall berepresentative of the pipe when made and test

conditions shall be consistent with conditions of theintended use. Particular attention shall be paid tomaintaining the concentration of trace materials intest liquors and to the temperature of the test.

When assessing the chemical resistance of alaminate, in addition to determining changes inmass, dimensions, and strength, the laminate shallbe examined for blisters, resin crazing, change inappearance of the fibres and loss of gloss, any ofwhich may be significant.

NOTE 2 Attention is drawn to the fact that the chemicalresistance of a laminate under stress may be different to that ofan unstressed coupon. The duration of the tests is important, as

the results of short term tests can be misleading.

12 Construction of a chemical liner

NOTE The basis of the design of GRP pipes is the strength ofthe glass reinforcement. Glass is adversely affected by manychemicals and therefore it is necessary to protect the structurallaminate from process liquors. The type and extent of theprotection required depends upon the operating conditions and itmay be that more than one of the liners described will besatisfactory for any particular process condition. It is importantthat the integrity of the selected liner is maintained throughoutthe pipework system.

12.1 Thermoplastics liners. Where athermoplastics lining is used the minimum bond

strength of the reinforcement to the lining shallbe 7.0 N/mm2 in direct shear and 7 N/mm width inpeel, when tested by the methods described in B.6 and B.7.

NOTE This strength will normally be achieved by the inclusionof a laminate with a minimum of 450 g/m2 chopped strand matand glass content between 25 % and 33 % immediately behindthe thermoplastics liner.

12.2 Thermoset liners. Thermoset liners availablein constructions shall be as follows.

Type 1 shall comprise a corrosion barrierconsisting of a resin rich layer reinforced with Cglass or synthetic fibre tissue with a thickness of

between 0.25 mm and 1.0 mm. This barrier shallbe followed by an initial laminate containing aminimum of 900 g/m2 chopped strand mat withglass content of between 25 % and 33 % by masswhen determined by the method described inBS 2782:Method 1002.

Type 2 (epoxide resin construction only) shallcomprise a corrosion barrier consisting of a resinrich layer reinforced with C glass or syntheticfibre tissue with a uniform thickness of 0.25 mmto 1.0 mm.

Type 3 shall comprise a corrosion barrier

consisting of a resin rich layer of thicknessbetween 1 mm and 2 mm which shall bereinforced.

13 Flammability

Where pipe is intended to convey flammable fluidsthe resin in the external surface layers shall bemodified so as to have a surface spread of flamecharacteristic that complies with clause 2 ofBS 476-7:1971. The test shall be carried out on alaminate representative of that to be used for thepipe.

Type of reinforcement Property

Ultimate tensileunit strength

(see B.3)

Unit modulus(see B.4)

Lap shearstrength(see B.5)

N/mm(width per

kg/m2 glass)

N/mm(width per

kg/m2 glass)

N/mm2

Chopped strand mat 200 14 000 7.0

Woven roving clothsquare woven

250 16 000 6.0

biased woven less than 5.1 : 1major direction

minor direction

43090

23 00010 000

6.06.0

baised woven equal or more than 5.1 : 1major direction

450 25 000 6.0

Continuous rovings 500 28 000 6.0


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Section 3. Design and designcalculations

14 General

14.1 Considerations for design. Themanufacturer shall ensure that the information setout in Appendix A is available before commencing adesign.

All pipes, fittings and joints shall be designed to themaximum continuous pressure rating under themost severe combination of all loads due to thefollowing:

a) internal pressure or vacuum;

b) test pressure requirement;

c) bending loads from pipe and contents;

d) earth loading;

e) design temperature change and consequentthermal expansion or contraction;

f) bending moments due to applied external loads;

g) vibration;

h) all anchor loads.

The design of fittings shall be confirmed assatisfactory by the testing of prototypes.

NOTE 1 All pipes should be designed to take the maximumdesign end load due to pressure except when rubber ring seals are

used when the end load requirement may be waived.NOTE 2 The anchor loads should be determined from thepipeline flexibility calculations and pressure thrust, the latterbeing equal to the maximum pressure times the largest internalcross section of the pipe.

NOTE 3 In the consideration of the membrane strains an equalstrain in all layers should be assumed.

NOTE 4 Loads may be imposed by personnel during erectionand operation and should be acknowledged.

14.2 Basis for design

NOTE 1 The design procedure in this standard takes advantageof the ease with which the laminate details can be varied to suitthe loads imposed by operating and test conditions in thedifferent regions.

When designing for process plant pipework in reinforced plastics

it is most desirable to work in terms of unit load (i.e. force per unitwidth per unit mass of glass) rather than stresses (i.e. force perunit area).

Where the design calculations require the use ofallowable compressive unit loadings these shall bedetermined by the method of substituting theultimate compressive unit loading for the ultimatetensile unit loading in equation (2).

Ultimate compressive unit load shall be determined,when required, for each laminate layer concerned bythe method described in BS 2782:Method 345A.

Where the design incorporates reinforcement withdirectional properties (e.g. woven rovings), the

orientation of the fibres shall be specified in order toensure that the structural properties required bythe design are attained.

NOTE 2 Worked examples of this design method are givenin Appendix C.

14.3 Conditions for design14.3.1 Design temperature. The design temperatureshall be the maximum temperature it is possible forthe pipe to attain under operating conditions(including boil-out, where applicable).

14.3.2 Design pressure. The design pressure (i.e. thepressure to be used in the equation for the purposeof calculation) shall be not less than:

a) the pressure that will exist in the system whenthe pressure relieving device starts to relieve, orthe set pressure of the pressure relieving device,whichever is the higher;

b) the maximum pressure that can be attained inservice where this pressure is not limited by arelieving device.

The value of the design pressure to be used in theequations in this section shall include the statichead where applicable, unless this is takenseparately into account in the equation.

14.3.3 Design vacuum

NOTE The design vacuum is the lowest pressure to begenerated in the pipe during operation.

Pipes subject to vacuum shall be designed to avoidthe risk of failure due to elastic instability.

14.4 Factors for design

14.4.1 Design factor. The design factor K shall becalculated from equation (1).

k1 to k5 represent part factors determined by themethod of manufacture and operating conditions.The intention of this procedure is that no pipe orfitting designed in accordance with this standardshall have a design factor of less than 6.

Values for part factors k1 to k5 are determined asfollows:

a) Factor relating to method of manufacture, k1.This factor shall be the value taken from Table 4appropriate to the method of manufacture to beadopted.

Table 4 — Factor relating to method ofmanufacture

K = 3 × k1 × k2 × k3 × k4 × k5 (1)

Method of manufacture Part factor k1

Handwork 1.5

Repeatable machine controlled work 1.5

Spray application 3.0


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b) Factor relating to long term behaviour, k2. Thisfactor shall be 1.2 for pipe having a

thermoplastics liner. The factor for pipe withouta thermoplastics liner shall be chosen within therange 1.2 and 2.0 based on the following criteria.If data are not available a factor of 2.0 shall beused.

After exposing unstressed laminate to theprocess conditions expected for the designlifetime of the pipe the loss in ultimate tensilestrength shall be used to fix the value of thefactor in accordance with Table 5.

Table 5 — Factor relating to loss in ultimatetensile strength

NOTE It is emphasized that thermoplastics liners are usedfor chemical resistance only and should not be considered ascontributing to the strength of the pipe, but they mayinfluence other properties of the pipe, e.g. thermal expansion.

c) Factor relating to temperature, k3. This factoris dependent on the heat distortion temperature

of the resin system and shall be determinedfrom Figure 4.

d) Factor relating to cyclic loading, k4. This factorshall be determined from Figure 5, having regardto the expected operating conditions of the pipe.

e) Factor relating to the curing procedure, k5.Where the pipe is subjected to a complete curingprocedure, including a full post-cure at elevatedtemperature in the manufacturer’s works, thisfactor shall be 1.1; for all other curing proceduresthe value of 1.4 shall be used.

14.4.2 Allowable design strain

14.4.2.1 The allowable design strain for theconstituent components of the pipe, i.e. liner, resinsystem and each type of reinforcing material, in theprincipal direction shall be calculated.

14.4.2.2 The allowable strain for the thermoplasticsliner portion of the pipe shall be taken as a valueof 0.2 %.

14.4.2.3 The allowable strain, º, for each type ofresin system shall be 0.1ºR or 0.2 % whichever is thelesser.

NOTE If confirmation is required by testing a laminate themethod described in BS 2782:Method 320C should be used.

14.4.2.4 The allowable strain for each type ofreinforcing material shall be calculated from

equation (2).

14.4.2.5 Considering all the constituent partsin 14.4.2.2 to 14.4.2.4 the allowable designstrain, ºd, shall be the lowest value so calculated.

14.4.3 Allowable unit loading. The allowable unitloading for each type of resin and reinforcingmaterial shall be calculated from equation (3).

15 Laminate design and thickness15.1 Laminate design. For each pipe or fitting aproposed laminate construction shall be determinedby taking into account the design unit loading foreach constituent layer (as calculated from 14.4.3).These loadings shall be related to the unit loads tobe carried in the region concerned.

The overall unit modulus for the proposed laminateconstruction shall be calculated from equation (4).

The laminate design unit loading U LAM shall be

calculated from equation (5).

The above procedure shall not apply wherecontinuous rovings are filament wound at anangle ± Ú to the pipe axis. Values of circumferentialand longitudinal unit modulus for individual layersshall be obtained by reference to Figure 3. Values ofcircumferential and longitudinal design unit loadshall be calculated by application of the factorsgiven in Table 3.

NOTE 1 It is possible that more than one combination of layersmay satisfy the requirements of the laminate.

Alternatively, all but one (or two interdependent) values of nx may be fixed and the remaining value(s) determined.

The suitability of purpose of a laminate constructionshall be checked in every case using equation (6).

If the sum of the X , m and n terms exceeds Q by alarge margin, the laminate is overdesigned. If thesum of the terms is less than Q , one or more of thevalues of n shall be increased or a different laminateconstruction proposed. In all cases the calculationshall be repeated for the new construction.

Loss in tensile strength Factor k2

20 % 50 % Material unsuitable

(2)

ux = ºd X x (3)

X LAM = ( X 1m1n1 + X 2m2n3 + ... X xmxnx) (4)

U LAM = ºd X LAM (axial direction) (5)

U LAM > Q (6)

e x =u

X x K -----------


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The response of continuous roving wound pipe tobiaxial loading applied simultaneously is different

from the response when loads are appliedindependently. To assess the behaviour of combinedloads a complete anisotropic stress/strain analysisshall be carried out and the response of the laminateto the combined load examined (see foreword). Thenormal or shear strain in each layer shall beless than that calculated in 14.4.2.5. If the analysisis not available a biaxial failure envelope shall beconstructed as shown in the worked examplein Appendix C.

NOTE 2 Additional considerations are necessary if thepipework is to be subject to vacuum or external pressureconsiderations (see clause 17).

15.2 Thickness. Where values of thickness arerequired in the equations in this section thethickness of the laminate in the region underconsideration shall be taken as the sum of thethicknesses of the individual layers making up thatlaminate.

The nominal thickness of each layer, for designpurposes, shall be determined from the glasscontent for that layer by using the graph(see Figure 2).

In no case shall the actual laminate thickness(excluding any corrosion barrier) be less than 4 mmfor pipes manufactured with chopped strand mat

and 2 mm for filament wound pipes.

Abrupt changes in laminate thickness shall beavoided. The blending taper between regions ofdiffering thickness shall be not steeper than 1 in 6.

16 Design calculations for pipessubject to internal pressure

NOTE The equations in this section are derived from thin shelltheory.

16.1 Pipes subject to internal pressure. The circumferential and axial unit loads Q c andQ a (in N/mm) shall be calculated from equations (7)

and (8).

where

16.2 Pipes subject to combined loads

16.2.1 Horizontal pipes. The maximum axial unitload, Q

a, shall be calculated from equation (9) for the

combined effects of the following:

a) pressure and/or vacuum;

b) bending moments due to self-mass;

c) bending moments due to mass of contents;

d) bending moment due to any other external

source.

where

M is the total bending moment.

16.2.2 Vertical pipes. The maximum axial unit load

for conditions a) to d) in 16.2.1 plus the addition of

the mass of pipe, fittings, contents, and attachments

above or below the point of consideration shall be

calculated from equation (10).

where

F is the algebraic sum of all the appropriatevertical forces acting on the pipes adjacent to thesupport.

Vertical forces causing tension in the pipe shall beconsidered positive, and forces causing compressionshall be considered negative.

16.3 Permissible axial compressive load. A check calculation shall be made to ensure that the

region of the pipe subject to the highest compressiveload is adequate to resist collapse by local buckling.To make this check the overall unit modulus, X LAM,(for the axial direction using axial compressiveproperties) for the proposed construction shall becalculated from equation (4).

The permissible maximum axial compressive unitload, Q p, to resist buckling shall then be calculatedfrom equation (11) which includes a safety factorof 4.

The maximum compressive unit load shall in nocase exceed the value calculated in equation (6). If inthe original design it does, the laminateconstruction shall be modified, and the necessarycalculations repeated until this condition issatisfied.

17 Design calculations for pipessubject to vacuum

17.1 Pipes without stiffening rings. Thecircumferential unit load, Q c, shall be calculatedfrom equation (7).

(7)

(8)

p is the internal pressure (gauge) (in N/mm2);

Di is the internal diameter (in mm).

Circumferential unit load Q c

pD i

2-----------=

Axial unit load Q a pD i

4-----------=

(9)

(10)

(11)

Axial unit load Q a = pD i

4----------- ±

4M

; Di 2

-------------

Axial unit load Q a pD i

4---------- ± 4M

; Di 2

------------- ± F ; Di----------=

Q p0.6tX LAM

4 Di----------------------------=


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8 © BSI 03-1999

The maximum direct axial unit load, Q a, shall becalculated from equations (9) or (10) as appropriate.

From each of these values the appropriate thicknessof laminate shall be calculated and the largest valueobtained shall be used for calculations. Using as abasis a laminate construction which satisfies thisrequirement, the total thickness of the laminate, t,shall be determined as described in 15.2.

The composite modulus of the laminate,E LAM (in N/mm

2), shall also be calculated fromequation (12).

where

The value of t shall be greater than the value of theminimum wall thickness, tm, obtained usingequation (13) which includes a safety factor of 4.

If in the proposed design this condition is not

fulfilled the design shall be changed either byre-designing the laminate or by providing additionalstiffening rings (see 17.2). The calculation shallthen be repeated until an acceptable construction isindicated.

17.2 Pipes with stiffening rings. If thecalculations in 17.1 indicate an unacceptablelaminate thickness it may be preferable to re-designthe pipe to include stiffening rings.

The design of pipes with stiffening rings may beapproached by two methods.

a) Method 1. To fix the distance between

stiffeners by utilizing the spacing betweenflanges, anchors, or additional stiffeners andchecking the minimum thickness required toprevent collapse by using equations (13) or (14),which includes a safety factor of 4, dependent onthe value of the stiffener distance/diameter ratio:

where

b) Method 2. To fix the construction and hencethickness and calculate the required distancebetween stiffeners from equation (15).

The distance between stiffeners in either case shallnot exceed the value of J calculated fromequation (15).

For a proposed stiffening ring profile andcomposition it is then necessary to determine thediameter ( Ds) of the neutral axis of the stiffeningring. Subsequently it shall be ensured that thesecond moment of area of the designed stiffeningring, l, is not less than the value obtained fromequation (16):

where E LAM has been calculated from equation (12).

The permissible length of shell, J s, which may beregarded as effectively contributing to the amount ofthe stiffening ring section shall be

but in no case shall J s be taken as greater than J .

Stiffening rings shall extend completely round thecircumference of the pipe and any joints in thestiffener shall be so designed as to develop the full

stiffness of the ring.

Section 4. Dimension markings andinformation

18 Dimensions

18.1 Diameters

18.1.1 Unlined pipelines. The nominal size of pipesand fittings shall be one of the following values:

(12)

X LAM is the overall unit modulus of thelaminate under consideration determinedfrom equation (4);

t is the total thickness of the laminate.

(13)

(13)

E LAM X LAM

t-----------------=

tm

Do

4 p

2E LAM

-------------------- 0.33=

(14)

J is the distance between the centre line ofstiffeners;

Do is the outside diameter = Di + 2t.

(15)

(16)

J s = 0.75 √( Dot) (17)

25 32 40 50 65 80 100 125

150 200 250 300 350 400 450 500

600 700 800 900 1 000

l 0.18 DoJDs

2 p

E LAM----------------------------------------=


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BS 6464:1984

© BSI 03-1999 9

The manufacturer shall declare the actual internaldiameter, in mm, of the pipes and fittings related to

the relevant nominal size.18.1.2 uPVC lined pipelines using extruded pipe andmoulded fittings. The nominal size of pipe andfittings up to and including 500 shall be based onthe nominal size of the extruded pipe (see clause 7).

NOTE Account should be taken, on sizing of the system, of anyconsequential reduction of the bore size below that of unlinedpipe.

18.1.3 uPVC lined pipelines using fabricatedlinings. The nominal size of pipe and fittingsabove 500 shall be one of the relevant sizes specifiedin 18.1.1.

18.1.4 Polypropylene lined pipelines using

fabricated lining. The nominal size of pipe andfittings above 80 shall be one of the relevant sizesspecified in 18.1.1.

19 Tolerances on dimensions of pipesand fittings

19.1 Diameters. The tolerances on the declareddiameter measured at 23 ± 2 °C shall be as follows:

± 1.5 mm for pipes up to and including 150nominal size;

± 3 mm for pipes over 150 and up to 600 nominalsize;

± 0.5 % of the declared internal diameter forpipes over 600.

All deviations from roundness, such as ovality, withthe exception of pipe deformation due to its ownweight, shall be contained within these tolerances.

19.2 Length. The tolerances on length shall be asfollows:

± 1.5 mm for cut or fabricated lengths of pipeup to 4 m in length;

± 3.0 mm for cut or fabricated pipe largerthan 4 m in length.

19.3 Squareness of ends. All unflanged pipe shallbe cut square with the axis of the pipe towithin ± 3 mm for all nominal sizes up to andincluding 400 and to within ± 4 mm for all nominalsizes over 600.

19.4 Deviation from straightness. For pipes ofnominal size greater than 150 the deviation from

straightness of the bore of the pipe shall notexceed 0.3 % of the effective length of the pipeor 15 mm, whichever is the smaller. Deviation fromstraightness shall be measured with the pipe in anunstrained vertical position. Measurements shall betaken at four equidistant points around thecircumference. The average value of the maximumand minimum vertical distance between a straightedge, or taut chord, touching the ends of a pipe, andthe wall of the pipe in the case of a concave curve or,in the case of a convex curve, between a straightedge or taut chord which touches the wall of the pipeand is equidistant from the wall at the two ends of

the pipe, and the wall of the pipe at the end, isexpressed as a percentage of the effective length ofthe pipe.

19.5 Fittings. Tolerances on angles of fittings shallbe ± 1° for nominal sizes up to 600 and ± 0.5° fornominal sizes greater than 600.

20 Marking

Each pipe and fitting shall be permanently markedwith the following information:

a) manufacturer’s name or initials andidentification code;

b) nominal size;c) pressure rating and temperature rating;

d) number and date of this standard,i.e. BS 6464:19843);

e) resin type and thermoplastics liner type ifused.

21 Information

21.1 The manufacturer shall declare the lining andlaminate system to be employed which shall bespecified in full including the following detailsdetermined at the design stage:

a) lining system;

b) number of layers and notional thickness ofeach layer;

c) total minimum thickness of the laminatesystem;

3) Marking BS 6464:1984 on or in relation to a product is a claim by the manufacturer that the product has been manufactured to

the requirements of the standard. The accuracy of such a claim is therefore solely the manufacturer’s responsibility. Enquiries as

to the availability of third party certification to support such claims should be addressed to the Director, Quality Assurance

Division, BSI, Maylands Avenue, Hemel Hempstead, Herts HP2 4SQ for certification marks administered by BSI or to the

appropriate authority for other certification marks.


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BS 6464:1984

10 © BSI 03-1999

d) composition of each layer, including:

1) type and mass of reinforcement, e.g. chopped

strand mat, woven cloth, continuous rovingsetc.;

2) percentage by mass of fibrousreinforcement;

3) type of resin system.

NOTE Information on different methods of manufacture isgiven in Appendix D.

21.2 The manufacturer shall give recommendationsfor the installation of pipes and fittings complyingwith this standard either for above ground or belowground situations.

Section 5. Construction andworkmanship

22 Manufacturing conditions in worksinvolving the cure of resins

Materials shall be stored and used in compliancewith the supplier’s instructions; reinforcementmaterials shall be stored dry.

Unless a hot curing resin system is being used thetemperature of the working area shall bemaintained above 15 °C for any laminating processand the cure cycle of the resin system. All other

laminating work shall be discontinued wheneverthe air temperature falls to 10 °C or the dew point isreached (when condensation occurs).

The working area shall be suitably divided intoclearly defined sections for preparation ofreinforcement, mixing of resins, application,trimming and finishing.

23 Manufacturing procedure

23.1 The manufacturer shall eliminate as manyvariables as possible to ensure consistency in bothmaterials and fabrication, and shall provideadequate supervision at all stages of manufacture.

NOTE All operators to be employed should be experienced incarrying out the type of work involved in the order.Representative test pieces of laminate should be submitted toprove the competence of each operator unless evidence of priorsatisfactory work is available.

23.2 The requisite amount of resin, catalyst orhardener and any other ingredient such asaccelerator or permitted filler, shall be accuratelymeasured and thoroughly mixed. The amounts ofmixed resin and reinforcement used in the laminateand the number and type of layers applied shall berecorded where applicable; the records shall bemade available to the purchaser or inspecting

authority.

23.3 Where hand lay-up is used in themanufacturing procedure, rolling shall be used to

consolidate the laminate. Whilst good rolling isessential, the rolling pressure shall not be sufficientto cause disturbance of the distribution of thereinforcement or to break the fibre strands.

The manufacturer shall ensure that good adhesionis obtained between successive layers of thelaminate either by appropriate scheduling of themanufacturing operation or by removing the surfaceof the cured resin to expose the fibres.

Adjacent pieces of reinforcement shall beoverlapped by not less than 50 mm. The edges shallbe worked out by brushing with a stippling actionand all joints shall be staggered through the

thickness of the laminate.

Where directionally biased reinforcement is usedcare shall be taken to ensure that the high strengthfibres are adequately aligned in the correct directionto give the required strength.

The number, size and distribution of air bubbles,pits or inclusions shall be not greater thanpreviously submitted samples. Acceptable limits ofvisual defects shall be in accordancewith Appendix E.

23.4 Care shall be taken to avoid low exotherm,monomer loss (in polyester resins) and resin

drainage. Excessive exotherm shall be avoided in alllaminates. An elevated temperature post cure shallbe applied where this is required by the designprocedures (see 14.4).

24 Thermoplastics liners

24.1 If uPVC is the required liner uPVC pipecomplying with BS 3505 or BS 3506 shall be usedfor lining pipe up to 500 mm diameter. In the case oflarger pipes uPVC sheet complying with BS 3757shall be used and this shall be stress relieved in anoven at temperatures between 120 °C and 140 °C

for 15 min from attaining this temperature. All forming operations of uPVC shall be performedat a temperature between 120 °C and 140 °C.

24.2 Polypropylene and PVDF liners if requiredshall be formed from extruded sheets to which isattached a glass fibre backing. The thickness of thesheet shall be as specified in clause 7.

24.3 All welds shall be butt welds

Before welding of the liner commences the edges tobe welded, together with a filler rod, shall besuitably cleaned. In addition, glass backedthermoplastics liners shall have the glass backing

stripped back to a distance between 3 mm and 6 mmon either side of the weld preparation to ensure thatno glass filaments are included in the welded joint.


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BS 6464:1984

© BSI 03-1999 11

If welding is done by the hot gas filler rod technique,nitrogen or compressed air free from moisture, dirt

and oil shall be used for welding. In all cases thegrade of material of the filler rod shall be compatiblewith the liner material being welded. All edges to bebutt welded by filler rod shall be chamfered to givean included angle and a land as shown in Figure 6.

24.4 All welds shall be fully penetrating. Weldscompleted from one side only shall haveat least 70 % of the material strength; where thereis reasonable access to the weld from both sides theweld shall have at least 85 % of the materialstrength.

Tests shall be made by the method described in B.8.There shall be no obvious undercutting, degradation

of the material or breaks in the weld run.

NOTE All welders engaged on the fabrication of thermoplasticsliners should be required to demonstrate their ability to weld tothe requirements of liners to this standard.

24.5 The external surface of the weld shall befinished to a smooth contour before laminating andtested by the use of a high frequency spark tester ata voltage of 20 kV ± 10 %. Any weld that showsevidence of notches, lack of fusion or holes shall berejected. (See clause 30.)

24.6 In the case of flanged pipes the lining materialshall be carried over the face of the flange.

25 Fittings

25.1 The minimum dimensions of sockets shall be as

specified in Table 6.

25.2 The minimum dimensions of fittings,dependent upon the method of fabrication to be usedfor the pipeline described in Appendix F, shall becalculated from the appropriate method given inTable 7 using the relevant values given in Table 8.

NOTE 1 The location of the dimensions in Table 7 andTable 8 are shown in Figure 7 and Figure 8.

NOTE 2 The preferred method of manufacture for fittingsfrom 25 to 600 nominal size is by one-piece moulding.

25.3 The minimum thicknesses of flanges shall be asgiven in Table 9. The minimum dimensions of GRPbacking flanges and drilling dimensions in

accordance with class 150 of BS 1560, class 150 ofBS 3293 and Table 10 of BS 4504 shall be as givenin Table 10.

NOTE The relationships of these dimensions are given inFigure 9 and Figure 10.

25.4 Pipe supports shall have a minimum widthof 25 mm and a minimum contact arc of 120° on theunderside of an above ground pipe.

NOTE The frequency of support shall be such that the ratio ofdeflection to span should not exceed 1 : 300 when the pipe is filledwith the process fluid at the design temperature.

Piping should be supported and anchored so as to prevent undueloads on connected equipment, and at the same time to permitcontrolled expansion and contraction between anchors and

changes of direction. Anchors should be so designed that the loads are properlytransmitted into the wall of the pipe.


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BS 6464:1984

12 © BSI 03-1999

Table 6 — Minimum socket depths

Nominal size

of pipe

Minimum socket depth at various pressures

Up to 2.5 bar 4 bar 6 bar 10 bar 16 bar 25 bar 40 bar 64 bar

mm mm mm mm mm mm mm mm

25324050

6580

100125

150

200250300350

400450500

600700

800900

1 000

25252536

4040

5060

65

75100100100

100105105

110115

120135

150

25252536

4040

7075

75

75100100100

100105110

115120

120135

150

25252536

4040

7075

75

75100100105

120120125

150175

200225

250

25253236

4040

7075

75

75100100120

135143165

200235

265300

—

25254040

5060

7075

85

110150180220

240270300

— — — —

—

25404040

6585

100120

135

180220270300

— — — — —

— —

—

50505075

95115

145180

215

285 — — —

— — — — — — —

—

5875

95

150185

230290

—

— — — — — — — — —

— —

—


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BS 6464:1984

© BSI 03-1999 13

Table 7 — Equations for calculating fittings dimensions

Table 8 — Minimum separation dimensions to be used in equations of Table 7

Dimension Fabrication method

Method 1 Method 2 Method 3

B R + L2 R + L3 R + A + L2

C C 1 + L2 C 1 + L3 C 1 + A + L2

E 1 S d + D/2 S d + D/2 + L3d S d + D/2 + Ad

E 2 S d + d/2 S d + d/2 + L3D S d + d/2 + AD

L1 L2d + L2D + 2.5 ( D–d) L3D + L3D + 2.5 ( D–d) AD + Ad + L2D + 2.5 ( D–d)

H H d1 + H d2

NOTE 1 Subscripts D and d refer to the values for the related diameter of each branch.

NOTE 2 For location of dimensions see Figure 7 and Figure 8.

All dimensions in millimetres.

Nominal size D or d

A C1 H R S L2 L3

25405080

150150150175

505075

100

100100125125

75115150225

75757575

50505050

75757575

100150200250

200225275300

125100125100

150200225250

300225300250

75125150200

50757575

100125175200

300350400450

350400450475

125150175175

275325350375

300350400450

225275300350

75100100100

225275325350

500600700800

500500500550

200225275325

400450525575

500600700800

375450525600

100100100100

375450350400

9001 000

600650

350400

625675

9001 000

675750

100100

450500


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BS 6464:1984

14 © BSI 03-1999

Table 9 — Dimensions of flanges (see Figure 9 and Figure 10)

Stub flange (type A)

thickness, N A

Stub flange outside

diameter, Da

Flange (type B)

thickness, N B

Flange (type C)

thickness, N C

Design strain 0.2 % 0.16 % 0.13 % 0.1 % BS 1560:Class 150

BS 4504:Table 10.

0.2 % 0.1 %

Pipe nominalsize

Pressure up to 10 bar Pressure up to 10 bar

mm mm mm mm mm mm mm mm

253240

— — —

— — —

— — —

— — —

— — —

— — —

232425

10b

10b

10b

5065

1010

1010

1011

1213

102121

107127

2830

—

—

80100125150

10141516

11151617

12161718

14181920

133172194219

142162192218

32323232

— — — —

200250300350

18222626

20242929

22263131

24283434

276337406448

273328378438

38455055

—

— — —

400450500600

28303135

30323438

33353640

36383944

511546603714

489539594695

55606065

—

— — —

Pressure up to 6 bar BS 3293:Class 150

BS 4504:Table 10

Pressure up to 6 bar

700800900

1 000

36394346

39424750

43465054

47505559

829937

1 0451 159

810917

1 0171 124

55606570

—

— — —

a D = pitch circle diameter (p.c.d.) — bolt hole diameter.b These require a 6 mm steel backing flange (Figure 11, type A).


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BS 6464:1984

© BSI 03-1999 15

Table 10 — Thickness and mating dimensions of flanges and backing flanges (see Figure 10)

26 Joints

26.1 General. The types of joints in general use areas follows:

a) butt;

b) cemented spigot and socket;

c) flanged;

d) spigot and socket with elastomeric sealingrings.

NOTE 1 Type d) is not usually designed to take end loads.

Selection of the type of pipe joint shall be governedby the duty requirements, details of the pipeconstruction and economic considerations. In allcases the detail of the joint shall be so designed thatthe chemical resistance of the joint is acceptable forits application.

All joints of types a), b) and c) shall be designed andconstructed to take at least the same end load as thepipe.

NOTE 2 The recommended jointing fabrication methods forfactory and site use are given in Appendix F.

Where the design of a butt joint is developed it shallincorporate an additional design factor of 1.2 × thepipe properties.

When uPVC is the lining material injection mouldedfittings with sockets suitable for solvent cementingmay be used and in such cases the followingrequirements shall apply.

1) uPVC pipe shall comply with either BS 3505 orBS 3506 and sizes shall not exceed 150 nominalsize.

2) Fittings shall comply with BS 4346-1. The useof moulded stub or full face flange fittings withsockets is not permitted. Flanges shall be asdetailed in 26.4.4.

3) Solvent cements shall comply with BS 4346-3

and shall be chosen such that the chemicalresistance of the joint is suitable for the chemicalconditions within the pipe.

Pipe

nominalsize

Backing flange

thicknessa , W

Outside diameter and drilling information in

accordance with class 150 of BS 1560

Outside diameter and drilling

information in accordance with Table 10of BS 4504

Pressure 10 barO.D P.C.D. Hole

diameterBolts O.D. P.C.D Hole

diameterBolts

Solid Splitb Number Size Number Size

mm mm mm mm in mm in mm mm mm

2532405065

— — —

1010

— — — 1414

115125134152178

79.488.998.4

120.6139.7

5/85/85/83/43/4

15.915.915.919.019.0

44444

1/21/21/25/85/8

115140150165185

85100110125145

1418181818

44444

M12M16M16M16M16

80100

125150

1012

1213

1417

1718

190229

254279

152.4190.5

215.9241.3

3/43/

47/87/8

19.019.0

22.222.2

48

88

5/85

/83/43/4

200220

250285

160180

210240

1818

1822

88

88

M16M16

M16M20

200250300350

15182122

21253031

343406483533

298.4362.0431.8476.2

7/81

1

11/8

22.225.425.428.6

8121212

3/47/87/81

340395445505

295350400460

22222222

8121216

M20M20M20M20

400450500600

24252732

34353845

597635698813

539.8577.8635.0749.3

11/811/411/413/8

28.631.831.834.9

16162020

111/811/411/4

565615670780

515565620725

26262630

16202020

M24M24M24M27

Pressure 6 bar Dimensions and drilling in accordance withclass 150 of BS 3293

700800900

1 000

29323539

41454955

927c

1 061c

1 168c

1 289c

864c

978c

1 086c

1 200c

13/815/815/815/8

34.941.341.341.3

28283236

11/411/211/211/2

8951 0151 1151 230

840950

1 0501 160

30333336

24242828

M27M30M30M33

a Based on rubber gaskets with a seating stress of 2.32 N/mm2.b Two-part split flanges.c These values are metric conversions.


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BS 6464:1984

16 © BSI 03-1999

4) Before application of glass fibre reinforcement,all external steps at the joints shall be blended

into the pipe surface with a minimum taperof 1 in 6 using a filled resin paste which shallsatisfy the bond shear strength requirementof 12.1.

5) The design temperature of systemsincorporating injection moulded fittings shall notexceed 40 °C and the design pressure shall notexceed 6 bar.

26.2 Alignment. The alignment of the pipes shallbe such that the step at the joint shall not exceed thefollowing.

NOTE It is recommended that jigs should be used to ensurethat butt and cemented joints are aligned and held rigidly in thisposition during the jointing process. The position of the pipesshould be maintained until the joint has adequate mechanicalstrength.

26.3 Lined pipe. The joint shall be so constructedthat only the liner comes in contact with the fluid. Inthe case of flanged pipes the lining material shall becarried over the face of the flange. In the case of butt

joints the thermoplastics liners shall be joined bywelding.

26.4 Joint types

26.4.1 Butt joints in unlined pipes. The ends of thepipe shall be chamfered back at a slope of 1 in 6leaving intact the chemical resistant innerlaminate. The surface of the pipe to be overlaid shallbe freshly abraded to remove the resin-rich surfaceand expose the glass fibre over an areaextending 25 mm beyond the joint overlay. Thechemically resistant resin cement shall be applied tothe ends of the pipe with the pipes butted and fixed

in position (see Figure 11). The space between thetwo chamfered surfaces shall be filled to a depth ofat least 3 mm using the resin cement. The initiallayer, of minimum width 50 mm over the chamferedsurfaces shall consist of a laminate of choppedstrand mat and the specified resin.

In the case of type 1 and type 3 pipes (see 12.2) theminimum total mass of chopped strand mat shallbe 900 g/m2 which shall be applied in at least twolayers. The glass content of the laminate shall bebetween 25 % and 33 % when determined by themethod described in BS 2782:Method 1002.

In the case of type 2 pipes (see 12.2) the minimummass of chopped strand mat shall be 600 g/m2 and

have a glass content between 25 % and 33 % whendetermined by the method described inBS 2782:Method 1002.

The joint shall be overlaid with suitable laminatessuch that the hoop, axial and inter-laminar sheerstrengths of the joint shall be at least equal to thestrength of the pipe.

The length of the overlay for pipes up to andincluding nominal size 100 shall be not less than thevalues given in Table 10. For pipes with nominalsize greater than 100 the overlay length shall becalculated from the equations (18) or (19).

where

An outer-layer of chopped strand mat shall beprovided, together with an outer resin-rich layer.

The outer edges of the overlay shall taper down tothe pipe so that they do not form stress raisers.

When practicable the interior of the joints shall befreshly abraded to remove the glass finish andsealed with a minimum of 900 g/m2 chopped strandmat followed by a surface tissue layer and sealingcoat. This internal laminate shall not be consideredas making a contribution to the strength of the joint.The pipe manufacturer shall provide precise detailsof the laminate to be used for the joint and shallprovide full test evidence that illustrates that a jointso produced is satisfactory.

26.4.2 Butt joints in lined pipes. The ends of the pipeshall be chamfered back at a slope of 1 in 6 leavingintact the thermoplastics liner (see Figure 6). The

liner shall be prepared for welding as specifiedin 24.3, fixed in position and welded. The bondstrengths between the area adjacent to the weld andthe overlay shall comply with 12.1. The initialoverlay using 600 g/m2 of chopped strand mat shallhave a glass content of between 25 % and 33 % whendetermined by the method described inBS 2782:Method 1002.

The joints shall then be overlaid with a suitablelaminate such that the hoop axial and inter-laminarshear strengths of the joint shall be at least equal tothe strength of the pipe.

The length of the overlay for pipes up to andincluding 100 nominal size shall be not less than theappropriate value given in Table 11.

Pipe nominal size Step

Up to and including 200 1 mm

Above 200 up to and including 400 1.5 mm

Above 400 2 mm

(18)

(19)

U LAM is determined in the axial direction.

Overlay length 2 KU LAM Lap shear strength------------------------------------------------------=

or Di

2------ whichever is the greater


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BS 6464:1984

© BSI 03-1999 17

For pipes of nominal size greater than 100 theoverlay length shall be calculated from

equations (18) or (19), whichever is the greater,where U LAM is determined in the axial direction.

An outer layer of chopped strand mat shall beprovided, together with an outer resin rich layer.

The outer edges of the overlay shall taper down tothe pipe so that they do not form stress raisers. Thepipe manufacturer shall provide precise details ofthe laminate to be used for the joint and shallprovide full test evidence that illustrates that the joint so produced is satisfactory.

Table 11 — Minimum butt joint overlaylengths including taper

26.4.3 Cemented spigot and socket joints in unlined pipes and fittings. Either parallel or taper spigotand socket joints shall be used. The socket shall beformed either as an integral part of the pipe orfitting or as a part of a socket coupling. Socket jointsshall comply with the following.

a) In all cases the hoop axial and interlaminarshear strength of the socket joint shall be at leastequal to the hoop axial and interlaminar strengthof the pipe.

b) The depth of the socket shall be equal to orgreater than the appropriate value givenin Table 5 always provided that the design strainlimitation is observed, or as calculated fromequation (20), whichever gives the greater value.

where

U LAM is in the axial direction

c) The manufacturer shall provide a cement thatis suitable for the process conditions for which thepipe is intended.

d) The joint shall be designed so that thethickness of the cement is between 0.15 mmand 1.5 mm.

e) The bond between the pipe, socket and cementshall have a minimum strength of 7 N/mm2. The

type test to prove conformance shall be carriedout by the method described in BS 5350-C5 usingdouble overlap joints as test pieces.

f) The manufacturer shall state the minimumambient conditions required for the bondingcement to cure and provide precise details of themethod of assembly and proof of suitability.

g) When practicable the interior of the joints shallbe freshly abraded to remove glass and shall besealed with a laminate containing a minimumof 900 g/m2 chopped strand mat which shall becovered by a surface tissue layer and sealing coat.

26.4.4 Flanged joints26.4.4.1 General. Flanged joints are classifiedaccording to type as follows.

Type A: stub flange with backing flange(see Figure 9).

Type B: full faced flange with or withoutthermoplastics liner (see Figure 10).

Type C: full faced flange with or withoutthermoplastics liner with backing flange(see Figure 10).

For pipe systems which have a test pressureabove 16 bar only stub flanges with loose steel

backing flanges shall be used.

Full faced flanges shall not be used for mating toraised face flanges.

Prototype testing shall be carried out on all flangedesigns to show that the flanged joint will sealunder the combined force of maximum designpressure plus an applied bending moment, M t,determined from equation (21).

where

U LAM is determined in the axial direction.

Unless there are records of satisfactory operatingperformance each flange design shall be proved bytest. The test pressure on flanged joints of nominalsize up to 600 shall be 6 × the rated pressure for thepipes with a pressure rating up to 10 bar.

26.4.4.2 Manufacturing tolerances. All flanges shallcomply with the following.

a) Flatness. Flange faces shall not be concave andshall be flat to within the following limits:

up to and including 450 nominal size

1 mm deviation;above 450 nominal size

1.5 mm deviation.

Nominalsize ofpipe

Minimum length of overlay for variousdesign working pressures

Up to 2.5 bar 4 bar 6 bar 10 bar 16 bar

mm mm mm mm mm

2532

100100

100100

100100

100100

100100

4050

100100

100100

100100

100100

100100

6580

150150

150150

150150

150150

150150

100 150 150 150 150 150

(20)Socket depthU LAM K

Lap shear strength------------------------------------------------------=

(21)M t =;

4----- U LAM

pD i 4

---------- Di

21.3× –


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The back faces of flanges shall be smoothed flatand shall be parallel to the flange face.

b) Squareness. Flanges shall be square to the pipeor fittings to within 1° up to 100 nominal size andto within 0.5° above 100 nominal size.

26.4.4.3 Assembly. Manufacturers’recommendations on the sequence of tighteningbolts and nuts shall be followed. If the maximumtorque is specified the threads of all bolts and nutsshall be greased.

26.4.5Socket and spigot joints with elastomericsealing rings

NOTE Socket and spigot joints are primarily designed for usewith underground pipes but, in general, are not suitable if endloads have to be transmitted through the pipe.

Alternative designs of joints making provision for end loads areavailable.

26.4.5.1 Joint quality. When used the socket andspigot joint shall be at least equal to the pipe inquality and performance, excluding axialproperties.

At the test pressure, the joint shall not leak in thefollowing conditions:

a) angular deflection;

b) draw;

c) misalignment;

d) diameter distortion;e) combination of a) to d).

The elastomeric sealing ring shall comply withBS 2494, and shall be free from substances that canhave a detrimental effect on the pipe material andcontents.

The elastomeric sealing ring shall have suitablechemical resistance and the volume swelling shallnot exceed 20 % after immersion in the process fluidfor 4 weeks at the temperature of intended use.

26.4.5.2 Joint requirements. For pressure pipe thefollowing joint requirements shall be met when

gauge pressures of 0.1 bar and 1.5 × nominalpressure of the pipe, measured at the top of the pipe,are maintained for 30 min.

For non-pressure pipe the following jointrequirements shall be met when gauge pressures

of 0.1 bar and 1.5 bar, measured at the top of thepipe, are maintained for 30 min.

a) Angular deflection. The joint shall withstand,without leakage and without stressing the spigotand socket, a minimum free angular deflection of:

3° for pipes of nominal size equal to orless than 500;

2° for pipes of nominal size greater than 500and up to and including 900;

1° for pipes of nominal size greater than 900and up to and including 1 000.

The manufacturers shall advise the angular

deflection permissible at installation.

b) Draw. The joint shall withstand withoutleakage a minimum draw of 0.25 % of themaximum pipe length, in addition to angulardeflection.

c) Misalignment. The joint shall withstandmisalignment without leakage when a forceof 20 N/mm of internal diameter, Di, is applied.For this maximum misalignment thecompression of the elastomeric sealing ring shallremain within limits appropriate to the type ofring used.

d) Diameter distortion. When the barrel of thepipe (excluding the socket) has reached amaximum diameter distortion of 5 % of thenominal diameter, the resultant ovality in the joint shall not allow leakage. In no case shall thedistortion load exceed that given in c).

e) Combination of joint requirements. The jointshall withstand a combination of angulardeflection, draw, misalignment, and diameterdistortion as indicated in a), b), c) and d) above.

Section 6. Testing

27 Tests for design

27.1 General. Manufacturers shall demonstratetheir ability to design and/or produce satisfactorypipes and fittings for the specified duty. Ifacceptable documentary evidence of past experienceis not available, prototype pipe shall be made andtested.

NOTE The prototype tests may be witnessed by the purchaseror inspecting authority.

27.2 Manufacture of prototype pipes andfittings. Prototype pipes and fittings shall be asfollows:

a) the pipes and fittings shall be identical indesign and manufacture to the proposedproduction pipe;


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b) the length of the test pipe shall beat least 1 500 mm or 5 × pipe nominal size,

whichever is greater;c) the prototype test assembly shall incorporatefeatures which are typical of the pipeline design,e.g. bends, branch connections, flanges and pipe joints;

d) the length of pipe for the negative pressure testshall be representative of the maximum designedfree installation length.

27.3 Tests to be applied to prototype pipes andfittings. Where the proposed pipe system isdesigned so that the pipes are not subjected to endload in service, provision shall be made in the test to

avoid incurring end loads. The tests shalldemonstrate resistance to specific modes of failureand shall include one or more of the followingappropriate to the intended service conditions.

a) Strain determination test. Determination ofgeneral and local strains by measurement (usingstrain gauges or other suitable methods) whenthe pipe is hydrostatically pressurized to thedesign pressure.

b) Fatigue test. Determination of the fatiguestrength of the pipe and/or fitting by cyclicvariations of pressure between limits.

NOTE The test fluid should be preferably the process fluid.

c) Short term burst pressure test. Determinationof the factor of safety to failure and the mode offailure by hydrostatically pressurizing the pipeuntil failure occurs.

d) Buckling test under negative internal pressure.Determination of the resistance to collapse undernegative pressure. The length of the test pipesshall be as specified in item d) of 27.2.

All pipes and fittings shall be adequately supportedduring the tests described in 27.4.

27.4 Performance during prototype testing.Pipes and fittings shall meet the following criteria.

a) Strain determination test. The measured strainshall not exceed 0.26 % when the pipe is testedhydrostatically to at least 1.3 times the designpressure strain.

b) Fatigue test. The pipe shall withstand 10 timesthe estimated number of pressure cycles requiredin the life of the pipe.

c) Short term burst pressure test. The pipe shallwithstand a pressure at least K (see 14.4) timesthe rated pressure without bursting, andweepage shall not occur below a pressureof 0.75 × K × rated pressure.

NOTE To determine the burst pressure it is permitted to usea loose liner in a separate pipe test piece.

d) Buckling test under negative internal pressure.The pipe shall withstand a negative pressure of 4

times the design negative pressure or 0.1 bargauge whichever is the lower pressure.

27.5 Records of tests. Records of all prototypetests shall be retained by the manufacturer andshall be made available to the purchaser andinspecting authority as required.

27.6 Chemical tests. Chemical resistance testsshall be done whenever there is no previousexperience of the process conditions. The testspecimens used shall be representative of the pipeas produced.

27.7 Additional tests. Additional tests such as the

heat distortion temperature test, mechanicalproperties of the laminate, abrasion or bondstrength between lining and laminates shall becarried out where previous experience is notdocumented.

28 Production testing

28.1 General. The frequency at which productionpipes are to be tested shall be agreed at the tenderstage.

NOTE It is recommended that a minimum of 10 % of pipes andfittings should be hydrostatically pressure tested at themanufacturer’s works.

28.2 Dimensional requirements. The dimensionsof test pieces shall be as follows.

a) Diameters, lengths and straightness shall bewithin the specified tolerances given in clause 19.Due care shall be taken to avoid the effect ofself-weight of the pipe or fitting.

b) Flatness of flange faces and alignment to pipeshall be within the tolerances given in 26.4.4.2.

NOTE Flatness of flanges should be assessed only after allthe reinforcement has been applied and the resin has cured.

28.3 Surface finish. The pipes and fittings shall beinspected for surface defects and comply with

Appendix E.28.4 Cure. The extent of cure of the laminate shallbe tested by determining the Barcol hardness inaccordance with the method described inBS 2782:Method 1001 which shall be within 10 % ofthe resin manufacturer’s published value. Theacetone extract shall not exceed the resinmanufacturer’s recommendation.

28.5 Hydrostatic testing. Pipes shall behydrostatically tested to 1.3 times the designpressure. The test pressure shall be applied andmaintained for a sufficient time to permit athorough examination to be made of the pipe but in

any case for not less than 1 h. Any indication ofleakage or excessive strain shall be cause forrejection.


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NOTE Care should be taken to ensure that the test pressure isnot exceeded during hydrostatic testing. Over-pressurizationmay lead to laminate damage which is irreparable and would be

cause for rejection of the pipe.

28.6 Examination after pressure testing. Oncompletion of the pressure test the pipe and/orfitting shall be inspected internally and externally. Any indication of cracking, resin crazing, orexcessive strain shall be cause for rejection. Wherepracticable pipes with thermoplastics linings shallbe spark tested after completion of testing; anyevidence of cracking or weld defect shall be cause forrejection.

29 Welding procedure tests forthermoplastics linings

The test pieces shall incorporate 300 mm long buttwelds made by joining two pieces of the material tobe used for the lining, each 300 mm longand 125 mm wide. The weld shall be made in thesame way as the production welds and shall includeat least one stop and start in each run. Weldingprocedure for the test welds shall be in accordancewith clause 24.

After completion, the test weld shall be examinedvisually and by the use of a high frequency sparktester giving a minimum peak voltage of 20 kV. Anyweld showing evidence of notches, lack of fusion or

pinholes shall not be used for tensile testing.Test pieces shall be machined from the weldedsample and subjected to the tensile test describedin B.8. The tensile strength across the weld shall benot less than 70 % or 85 % of the tensile strength ofwelded sheet as appropriate to the type of weld(see 24.4).

NOTE If any test weld shows evidence of notches, lack of fusionor pinholes or the tensile strength requirements of 24.4 are notmet, the welding procedure should be modified or the welderreceive further training, as appropriate, until all test welds aresatisfactory.

30 Tests for production welds inthermoplastics linings

All production welds shall be examined visually andby high frequency spark testequipment (20 kV ± 10 %) at the stages specifiedbelow:

a) after the first weld run;

b) after completion of the weld;

c) after pressure testing if practicable.

Tests a) and b) shall be completed before any primeror reinforcement is applied to the weld area and atemporary earthing strip shall be provided behind

the weld. This strip shall be removed after sparktesting.

Any defective areas, other than isolated pinholes, inthe first run, shall be removed and shall be suitably

repaired and again spark tested to the satisfactionof the inspection authority before fabricationcontinues. Where adjacent defects areless than 15 mm apart they shall be treated as asingle, large defect.

31 Production samples for mechanicaltests on a laminate

31.1 General. Test pieces shall, when possible, betaken from waste areas provided that they aretypical of the laminate they represent. Where thismethod is impracticable test pieces shall be laid upby the operator at the same time, with the samematerials and in the same manner as the item theyrepresent, and cured under the same conditions asthe main laminate.

31.2 Mechanical properties of laminates. Thefollowing tests shall be carried out to verify thematerial properties specified in section 2:

a) ultimate tensile unit strength (see B.3);

b) ultimate compressive unit loading if required(see 14.2);

c) unit modulus (see B.4);

d) lap shear strength (see B.5);

e) shear and peel strengths, if a thermoplasticslining is used (see B.5 and B.7).

Section 7. Inspection and testing

32 Facilities for inspection and testing

The manufacturer shall furnish and prepare thenecessary test pieces for the tests specified. If thetesting is to be done at his own works themanufacturer shall supply the necessary labour andappliances. Failing facilities at his own works themanufacturer shall arrange for the tests to be madeelsewhere.

When required by the order or drawing, test piecesshall be made available for test in the purchaser’slaboratories. When specified all tests shall bewitnessed by the inspecting authority and duenotice shall be given by the manufacturer to permitcompliance.

33 Certification of inspection andtesting

In case of joint responsibility for the inspection andtesting of pipes and fittings signed documentaryevidence of the results of all the completedinspections and tests shall be forwarded to theinspecting authority responsible for witnessing thefinal tests, prior to the conduction of these tests.


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Upon satisfactory completion of the order theorganizations responsible for design, construction

and inspection shall furnish duplicate copies of acertificate to the purchaser, stating that the design,construction and testing comply with therequirements specified in this standard. Whereapplicable the actual tests results obtained shall bestated on or with the certificate.

NOTE Inspection should include the following stages asappropriate:

a) inspection of workshop conditions where manufacture willbe carried out;

b) inspection of works records relating to the control and issueof materials, resin mixing, etc.;

c) identification of the materials of construction and theirstorage conditions;

d) approval of welding procedures and welders;

e) witnessing of spark tests on welds in thermoplastics liningswhere these are incorporated;

f) examination during hand lay-up, spray application,winding, die-moulding and jointing of resin glass laminates;

g) examination of any repairs carried out during construction;

h) examination on completion of construction, during pressuretesting, and before any pigmented coatings are applied.Where it is required to use transmitted light duringinspection, agreement should be reached between thepurchaser and the manufacturer on the stage for applying anypigmented coating.


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Appendix A Information to be given with an enquiry or tender or on receipt oforder

The information detailed below is to be given with an enquiry or tender or on receipt of order asappropriate.

a) Process conditions:

1) materials to be conveyed including minor constituents (names, concentrations and densities);

2) design pressure or vacuum and temperature;

3) operating pressure or vacuum and temperature;

4) mode of operation, e.g. process cycling conditions;

5) risk of surge pressures, e.g. from pumps and valves;

6) any abrasion or erosion problems which may be encountered.

b) Site conditions:

1) nature of ambient atmosphere including any extremes of temperature;2) in the case of buried pipes, information on ground conditions and expected loading, e.g. traffic.

c) Materials of construction:

1) lining material (which may consist of thermoplastics material or a resin rich layer and itsreinforcement);

2) resin systems to be used;

3) form(s) of reinforcement including type, number and arrangement of individual layers includingany sacrificial layers if used;

4) forms of stiffening where used;

5) mechanical properties of materials;

6) if required, fire resisting finish;

7) if required, pigments or UV absorbers in outer layer.

d) Design details:

1) essential dimensions, including tolerances on drawings;

2) nominal thickness, including tolerances, of corrosion-resistant lining (thermoplastics or resin richlayer) which does not contribute to strength;

3) details of welds in thermoplastics linings;

4) bolting and flange materials and details;

5) details of supporting arrangement, anchor points including integral reinforcement;

6) gasket materials and details;

7) details of external finish.

e) Standards of testing and inspectionf) Name of inspecting authority or organization

g) Requirements for packaging, despatch and installation

Appendix B Methods of test

B.1 General

B.1.1 Tests. This appendix describes methods for the testing of resins, laminates and thermoplastics forpipes and fittings in reinforced plastics. Tests are specified for the determination of the followingproperti

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