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

Confirmed January 2009

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BS 6464:1984

This British Standard, having been prepared under the direction of the Plastics Standards Committee, was published under the authority of the Board of BSI and comes into effect on 28 September 1984

BSI 03-1999

The following BSI references relate to the work on this standard:Committee reference PLM/9Draft for comment 76/50861 DC

ISBN 0 580 13776 7

Committees responsible for this British Standard

The preparation of this British Standard was entrusted by the Plastics Standards Committee (PLM/-) to Technical Committee PLM/9 upon which the following bodies were represented:

British Chemical Distributors and Traders Association Ltd.British Gas CorporationBritish Plastics FederationBritish Steel IndustryBritish Valve Manufacturers Association Ltd.Copper Tube Fittings Manufacturers AssociationDepartment of the Environment (Housing and Construction)Department of the Environment (PSA)Electricity Supply Industry in England and WalesEngineering Equipment and Materials Users AssociationInstitution of Civil EngineersInstitution of Municipal EngineersInstitution of Public Health EngineersInstitution of Water Engineers and ScientistsNational Association of Plumbing, Heating and Mechanical Services ContractorsPlastics and Rubber InstitutePlastics Land Drainage Manufacturers AssociationRoyal Institute of Public Health and HygieneSTC Water Regulations and Fittings SchemeWater Companies AssociationWater Research Centre

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

British Adhesive Manufacturers AssociationBritish Board of AgrmentGreater London CouncilHeating and Ventilating Contractors AssociationInstitute of PlumbingMinistry of Agriculture, Fisheries and FoodPitch Fibre Pipe Association of Great Britain

Amendments issued since publication

Amd. No. Date Comments

6294 November 1990

Indicated by a sideline in the margin

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Contents

PageCommittees responsible Inside front coverForeword iiiSection 1. General1 Scope 12 Definitions 13 Nomenclature, symbols and units for design 1Section 2. Materials and properties4 Thermosetting resin systems 25 Fibrous reinforcement 26 Aggregates and fillers 27 Thermoplastics liners 28 Cement for bonding spigot and socket joints 29 Mechanical properties 310 Thermal properties 311 Chemical properties 412 Construction of a chemical liner 413 Flammability 4Section 3. Design and design calculations14 General 515 Laminate design and thickness 616 Design calculations for pipes subject to internal pressure 717 Design calculations for pipes subject to vacuum 7Section 4. Dimension markings and information18 Dimensions 819 Tolerances on dimensions of pipes and fittings 920 Marking 921 Information 9Section 5. Construction and workmanship22 Manufacturing conditions in works involving the cure of resins 1023 Manufacturing procedure 1024 Thermoplastics liners 1025 Fittings 1126 Joints 15Section 6. Testing27 Tests for design 1828 Production testing 1929 Welding procedure tests for thermoplastics linings 2030 Tests for production welds in thermoplastics linings 2031 Production samples for mechanical tests on a laminate 20Section 7. Inspection and testing32 Facilities for inspection and testing 2033 Certification of inspection and testing 20Appendix A Information to be given with an enquiry or tender or on receipt of an order 22Appendix B Methods of test 22Appendix C Worked examples of the design method specified in section 3 28Appendix D Methods of manufacture of reinforced plastics pipes 34Appendix E Acceptable limits of visual defects 35

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PageAppendix F Pipework fabrication methods 36Figure 1 Limits of pressure and diameter 37Figure 2 Relationship between thickness and glass content for laminates with resin of relative density, (+), 1.1 to 1.3 38Figure 3 Relationship of unit modulus to winding angle 39Figure 4 Factor related to temperature 39Figure 5 Factor related to cyclic loading 40Figure 6 Butt joint build-up for lined pipe 41Figure 7 Pipework shapes for fabrication methods 1 and 2 42Figure 8 Flanged pipe fittings for method 3 43Figure 9 Typical stub flanges (type A) 44Figure 10 Typical full faced flanges (types B and C) 45Figure 11 Butt joint build-up for unlined pipe 46Figure 12 Test piece for the determination of shear strength of bond between thermoplastics lining and laminate 46Figure 13 Test piece for the determination of lap shear strength of laminate 47Figure 14 Test for the determination of peel strength of bond between thermoplastics liner and laminate 48Figure 15 Test piece for the tensile strength of thermoplastics sheet and welds 49Figure 16 Typical examples of laminate construction 50Figure 17 Biaxial failure envelope 51Table 1 Derivation of definitions relating to symbols 3Table 2 Minimum mechanical properties of reinforced laminate layers 4Table 3 Factors to be applied to design unit load of continuous rovings for different winding angles 3Table 4 Factor relating to method of manufacture 5Table 5 Factor relating to loss in ultimate tensile strength 6Table 6 Minimum socket depths 12Table 7 Equations for calculating fittings dimensions 13Table 8 Minimum separation dimensions to be used in equations of Table 7 13Table 9 Dimensions of flanges 14Table 10 Thickness and mating dimensions of flanges and backing flanges 15Table 11 Minimum butt joint overlay lengths including taper 17Table 12 Acceptable limits of visual defects 35Table 13 Pipework fabrication methods 36Publications referred to Inside back cover

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BS 6464:1984

BSI 03-1999 iii

Foreword

This British Standard has been prepared under the direction of the Plastics Standards 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 of materials, plastics and reinforcing systems and a number of different methods of manufacture.Metallic pipes, being made from materials which are isotropic, may conveniently be designed by calculating permissible stresses, based on measured tensile and ductile properties. Reinforced plastics are usually anisotropic, and the design method adopted in this standard, being based on unit loading, is particularly suited to the design of composite materials.This standard includes a method of calculation for an appropriate laminate construction based on the allowable unit loading and unit modulus for the type of composite 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 those under consideration within Technical Committee 138, Plastics pipes and fittings for 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 only by manufacturers and operators (see 23.1 and 24.4) who are competent and suitably equipped to fulfil all the requirements of this standard.It is expected that these principles will be proved by documentation of past experience 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 GRP pipes, joints and fittings intended for conveying, above or below ground, liquids including 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 in the production of pipeline envelopes for filament wound materials subject to biaxial loading, Composites (1978)A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application.

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

Summary of pagesThis 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 had amendments incorporated. This will be indicated in the amendment table on the inside front cover.L

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Section 1. General

1 ScopeThis British Standard specifies requirements for the materials, properties, design calculations, manufacture, inspection and testing of reinforced plastics pipes, fittings and joints consisting of thermosetting resin systems with glass fibre reinforcement (GRP) for process plants. Constructions both with and without a lining of thermoplastics are included. The information to be supplied for designs for pipes and fittings to this standard is given in Appendix A.This British Standard is not applicable in the following circumstances:

a) where the product of the design pressure in bar1) and the nominal diameter in millimetres is more than 11 000 (see Figure 1);b) where the operating temperature is outside the limits of 10 C to + 110 C;c) where the pipes may be subject to some applied external pressure other than that due to soil loading or vacuum;d) where there is a non-taint requirement, e.g. for the water and food industries, as no requirements are given for the effect of GRP on those materials.

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

1) Unstressed dip coupon testing of sample laminates may not necessarily give a valid indication of the long term resistance of the material to the actual internal and external chemical environment.2) Relatively small changes in the concentration of organic solvents and fluctuations in the operating temperatures can have marked effect on the chemical resistance of a GRP laminate.3) Most of the practical experience and design data on which this standard is based relates to pipes which were made by the hand lay-up process and contained large proportions of chopped strand mat reinforcement, and most of the practical experience under operating conditions was obtained with small diameter pipes which were only subject to low positive pressure.4) In many chemical plants pipework may be subject to occasional applied loads or impacts, which are not a part of the normal operating conditions. Care should be taken where such hazards are liable to arise.

It is recommended therefore that manufacturers of GRP pipes should demonstrate their ability to produce satisfactory pipe and fittings for any specific duty, either by producing documentary evidence of past performance under similar conditions or by making and testing prototype units.NOTE 2 The titles of the publications referred to in this standard are listed on the inside back cover.

2 DefinitionsFor the purpose of this British Standard the definitions given in BS 1755-1 apply, together with the following.

2.1 curing2)

the chemical reaction resulting in the final polymerized productNOTE It may be effected at ambient temperature or by the use of heat. In certain resin systems the full cure has to be effected in two stages of which the first may, and the second does, involve the application of heat. This second stage is known as the post-cure.

2.2 laminate2)

a resin reinforced with a form of glass fibre material

2.3 laying-up2)

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

2.4 aggregates

an inert granular material of a size range between 5 mm and 0.05 mm used as a design part of the structureNOTE Aggregates, such as silica sands, may be incorporated where they are a design part of the composite structure.

2.5 inert fillers

a fine material with a particle size below 0.05 mm

2.6 angle of lay,

the angle of the application of continuous rovings with respect to the horizontal axis

3 Nomenclature, symbols and units for designSeveral terms relating to the strength and load carrying capacity of individual layers of composite laminate are used in this standard. Some have similar but quite distinct meanings and because of their similarity and their application, particular care is required in their use. The terms concerned are listed in Table 1, with their definitions, symbols and units.

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

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BS 6464:1984

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

Section 2. Materials and properties

4 Thermosetting resin systemsNOTE 1 The thermosetting resins used for the manufacture of pipes and fittings may be of a number of types. There are many resin systems in each type and the properties of these systems vary, especially with respect to chemical resistance and heat distortion point.

Polyester and epoxy resin systems shall comply with BS 3532 and BS 3534 respectively.In order for the chemical reaction, resulting in the final polymerized product, to take place hardeners, catalysts and accelerators shall be added to the resin in accordance with the manufacturers recommendations.NOTE 2 The amount of hardener, catalyst and/or accelerator used is critical, as it can affect both the rate of reaction and extent of the cure.NOTE 3 If specified at the placement of an order, the outer layer of resin may incorporate pigments, dyes or specific ultraviolet light absorbers to prevent the transmission of UV light and/or for identification purposes.

5 Fibrous reinforcementThe 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 have a surface treatment compatible with the resin.

6 Aggregates and fillersThe resin used shall contain only fillers as required for viscosity control; they shall be limited to a maximum of 5 % of the mass of the resin and shall not interfere with the capability to visually inspect the laminate.Special additives, such as aggregates, graphite and fire retardants, etc., shall only be used to impart special properties, e.g. stiffness, conductivity.

7 Thermoplastics linersIf thermoplastics liners are used, the material shall be selected on the basis of resistance to the fluid to be carried.If unplasticized polyvinyl chloride (uPVC) is the specified liner, uPVC pipe complying with BS 3505 or BS 3506 shall be used. In the case of nominal sizes greater than 500 mm uPVC sheet complying with 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 polypropylene shall be 2 mm except for pipe of diameter 80 mm or less, for which the minimum thickness shall be 1.5 mm.NOTE Specialized liners such as CPVC, FEP, PVDF and PTFE may be required for very difficult process conditions.

8 Cement for bonding spigot and socket jointsThe manufacturer shall ensure that the bonding cement will be satisfactory for the chemical conditions specified, and shall state the minimum ambient conditions required for the bonding system to cure properly.The bonding cement shall develop a minimum internal shear strength of 7 N/mm2, when tested in accordance with the method described in B.2.When tested in accordance with the method described in BS 5350-C5, using double overlapped joint test pieces, bond materials to be used to join GRP sockets and spigots shall have a minimum bond strength of 7 N/mm2.

K overall design factor determined from the equation (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 construction

under consideration,mx mass of reinforcement per unit

area (kg/m2 glass) in one layer of type x,ux design unit loading

[N/mm {per kg/m2 glass}] for a selected layer of type x,

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

x allowable strain for each type of reinforcing material,

allowable strain, determined from resin properties,

d maximum design strain,R strain to failure of the unreinforced resin

determined by the method described in Method 320C of BS 2782:Method 320 A to F:1976.

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Table 1 Derivation of definitions relating to symbols

9 Mechanical propertiesThe mechanical properties of the laminate layers shall be not less than the values given in Table 2 when tested in accordance with the appropriate methods described in Appendix B.The values given in Table 2 apply to laminates incorporating only E glass reinforcement and complying with BS 3396, BS 3496, BS 3691 or BS 3749, and having a glass content by mass as determined by the method described in BS 2782:Method 1002 within the range shown in Figure 2.If higher values for mechanical properties are used as a basis for design the manufacturer shall demonstrate their accuracy.If continuous rovings are filament wound at an angle to the pipe axis, values of circumferential and longitudinal unit modulus shall be calculated by application of the graph in Figure 3 and the factors given in Table 3 as appropriate to the angle.

The use of other values for the factors in Table 3 is permitted if a rigorous anisotropic elastic analysis is carried out (see 14.1). This analysis shall allow for the contribution from each layer in the laminate and for interaction between normal and shear strains (see foreword). It shall be ensured that the strain transverse to the fibre direction is less than 0.1 %. In the absence of a rigorous anisotropic elastic analysis the axial strain shall be not more than 0.1 % for winding angles greater than 75.Table 3 Factors to be applied to design unit

load of continuous rovings for different winding angles

10 Thermal propertiesThe heat distortion temperature of the fully cured resin system used for the reinforced laminate, when determined in accordance with BS 2782:Method 121A, shall be not less than 20 C higher than the design temperature of use of the pipe and fitting.

Term Definition Derivation Symbol Unit

Ultimate tensile unit strength

The strength of a constituent layer of a laminate, expressed as force per unit width, per unit mass of reinforcement.

Obtained from the fracture load of a laminate of known construction, in a tensile test.

u N/mm (per kg/m2 glass)

Layer design unit loading

The load permitted to be applied to a constituent layer of a laminate, for the pipe or fitting under consideration.

Determined by multiplying the unit modulus, X, by the allowable strain for the particular laminate layer.

ux N/mm (per kg/m2 glass)

Unit modulus The ratio of the load per unit width per unit mass of glass to the corresponding direct strain, in a loaded tensile test piece.

Obtained from the measured load at 0.2 % strain in a tensile test.

X N/mm (per kg/m2 glass)

Laminate design unit loading

The load permitted to be applied to a laminate, expressed as force per unit width. The subscripts indicate a main (ULAM) or an overlay (UOVL)laminate.

Obtained by summing the load carrying capacities of all the layers in the laminate.

ULAMUOVL

N/mm width

Unit load The force per unit width carried by a laminate resulting from pressure or other loads applied to the pipe or fitting.

Obtained from the appropriate design calculations for the pipe or fitting under consideration.

Q N/mm width

Filament winding angle to axis

Circumferential factor

Longitudinal factor

0 < < 15 0 1

15 < < 75 0.5 0.5

75 < < 90 1 0

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Table 2 Minimum mechanical properties of reinforced laminate layers

11 Chemical propertiesNOTE 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 a laminate for a particular duty shall be established by tests carried out in accordance with the methods described in BS 4618-4.1. The test pieces shall be representative of the pipe when made and test conditions shall be consistent with conditions of the intended use. Particular attention shall be paid to maintaining the concentration of trace materials in test liquors and to the temperature of the test.When assessing the chemical resistance of a laminate, in addition to determining changes in mass, dimensions, and strength, the laminate shall be examined for blisters, resin crazing, change in appearance of the fibres and loss of gloss, any of which may be significant.NOTE 2 Attention is drawn to the fact that the chemical resistance of a laminate under stress may be different to that of an unstressed coupon. The duration of the tests is important, as the results of short term tests can be misleading.

12 Construction of a chemical linerNOTE The basis of the design of GRP pipes is the strength of the glass reinforcement. Glass is adversely affected by many chemicals and therefore it is necessary to protect the structural laminate from process liquors. The type and extent of the protection required depends upon the operating conditions and it may be that more than one of the liners described will be satisfactory for any particular process condition. It is important that the integrity of the selected liner is maintained throughout the pipework system.

12.1 Thermoplastics liners. Where a thermoplastics lining is used the minimum bond strength of the reinforcement to the lining shall be 7.0 N/mm2 in direct shear and 7 N/mm width in peel, when tested by the methods described in B.6 and B.7.

NOTE This strength will normally be achieved by the inclusion of a laminate with a minimum of 450 g/m2 chopped strand mat and glass content between 25 % and 33 % immediately behind the thermoplastics liner.12.2 Thermoset liners. Thermoset liners available in constructions shall be as follows.

Type 1 shall comprise a corrosion barrier consisting of a resin rich layer reinforced with C glass or synthetic fibre tissue with a thickness of between 0.25 mm and 1.0 mm. This barrier shall be followed by an initial laminate containing a minimum of 900 g/m2 chopped strand mat with glass content of between 25 % and 33 % by mass when determined by the method described in BS 2782:Method 1002.Type 2 (epoxide resin construction only) shall comprise a corrosion barrier consisting of a resin rich layer reinforced with C glass or synthetic fibre tissue with a uniform thickness of 0.25 mm to 1.0 mm.Type 3 shall comprise a corrosion barrier consisting of a resin rich layer of thickness between 1 mm and 2 mm which shall be reinforced.

13 FlammabilityWhere pipe is intended to convey flammable fluids the resin in the external surface layers shall be modified so as to have a surface spread of flame characteristic that complies with clause 2 of BS 476-7:1971. The test shall be carried out on a laminate representative of that to be used for the pipe.

Type of reinforcement Property

Ultimate tensile unit strength

(see B.3)

Unit modulus(see B.4)

Lap shear strength (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 directionminor 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 design calculations

14 General14.1 Considerations for design. The manufacturer shall ensure that the information set out in Appendix A is available before commencing a design.All pipes, fittings and joints shall be designed to the maximum continuous pressure rating under the most severe combination of all loads due to the following:

a) internal pressure or vacuum;b) test pressure requirement;c) bending loads from pipe and contents;d) earth loading;e) design temperature change and consequent thermal expansion or contraction;f) bending moments due to applied external loads;g) vibration;h) all anchor loads.

The design of fittings shall be confirmed as satisfactory by the testing of prototypes.NOTE 1 All pipes should be designed to take the maximum design 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 the pipeline flexibility calculations and pressure thrust, the latter being equal to the maximum pressure times the largest internal cross section of the pipe.NOTE 3 In the consideration of the membrane strains an equal strain in all layers should be assumed.NOTE 4 Loads may be imposed by personnel during erection and operation and should be acknowledged.

14.2 Basis for designNOTE 1 The design procedure in this standard takes advantage of the ease with which the laminate details can be varied to suit the loads imposed by operating and test conditions in the different 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 unit width per unit mass of glass) rather than stresses (i.e. force per unit area).

Where the design calculations require the use of allowable compressive unit loadings these shall be determined by the method of substituting the ultimate compressive unit loading for the ultimate tensile unit loading in equation (2).Ultimate compressive unit load shall be determined, when required, for each laminate layer concerned by the method described in BS 2782:Method 345A.Where the design incorporates reinforcement with directional properties (e.g. woven rovings), the orientation of the fibres shall be specified in order to ensure that the structural properties required by the design are attained.

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

14.3 Conditions for design

14.3.1 Design temperature. The design temperature shall be the maximum temperature it is possible for the pipe to attain under operating conditions (including boil-out, where applicable).14.3.2 Design pressure. The design pressure (i.e. the pressure to be used in the equation for the purpose of calculation) shall be not less than:

a) the pressure that will exist in the system when the pressure relieving device starts to relieve, or the set pressure of the pressure relieving device, whichever is the higher;b) the maximum pressure that can be attained in service where this pressure is not limited by a relieving device.

The value of the design pressure to be used in the equations in this section shall include the static head where applicable, unless this is taken separately into account in the equation.

14.3.3 Design vacuumNOTE The design vacuum is the lowest pressure to be generated in the pipe during operation.

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

14.4 Factors for design

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

k1 to k5 represent part factors determined by the method of manufacture and operating conditions. The intention of this procedure is that no pipe or fitting designed in accordance with this standard shall have a design factor of less than 6.Values for part factors k1 to k5 are determined as follows:

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

Table 4 Factor relating to method of manufacture

K = 3 k1 k2 k3 k4 k5 (1)

Method of manufacture Part factor k1

Handwork 1.5Repeatable machine controlled work 1.5Spray application 3.0

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b) Factor relating to long term behaviour, k2. This factor shall be 1.2 for pipe having a thermoplastics liner. The factor for pipe without a thermoplastics liner shall be chosen within the range 1.2 and 2.0 based on the following criteria. If data are not available a factor of 2.0 shall be used.After exposing unstressed laminate to the process conditions expected for the design lifetime of the pipe the loss in ultimate tensile strength shall be used to fix the value of the factor in accordance with Table 5.

Table 5 Factor relating to loss in ultimate tensile strength

NOTE It is emphasized that thermoplastics liners are used for chemical resistance only and should not be considered as contributing to the strength of the pipe, but they may influence other properties of the pipe, e.g. thermal expansion.

c) Factor relating to temperature, k3. This factor is dependent on the heat distortion temperature of the resin system and shall be determined from Figure 4.d) Factor relating to cyclic loading, k4. This factor shall be determined from Figure 5, having regard to the expected operating conditions of the pipe.e) Factor relating to the curing procedure, k5. Where the pipe is subjected to a complete curing procedure, including a full post-cure at elevated temperature in the manufacturers works, this factor shall be 1.1; for all other curing procedures the value of 1.4 shall be used.

14.4.2 Allowable design strain

14.4.2.1 The allowable design strain for the constituent components of the pipe, i.e. liner, resin system and each type of reinforcing material, in the principal direction shall be calculated.14.4.2.2 The allowable strain for the thermoplastics liner portion of the pipe shall be taken as a value of 0.2 %.14.4.2.3 The allowable strain, , for each type of resin system shall be 0.1R or 0.2 % whichever is the lesser.NOTE If confirmation is required by testing a laminate the method described in BS 2782:Method 320C should be used.

14.4.2.4 The allowable strain for each type of reinforcing material shall be calculated from equation (2).

14.4.2.5 Considering all the constituent parts in 14.4.2.2 to 14.4.2.4 the allowable design strain, d, shall be the lowest value so calculated.14.4.3 Allowable unit loading. The allowable unit loading for each type of resin and reinforcing material shall be calculated from equation (3).

15 Laminate design and thickness15.1 Laminate design. For each pipe or fitting a proposed laminate construction shall be determined by taking into account the design unit loading for each constituent layer (as calculated from 14.4.3). These loadings shall be related to the unit loads to be carried in the region concerned.The overall unit modulus for the proposed laminate construction shall be calculated from equation (4).

The laminate design unit loading ULAM shall be calculated from equation (5).

The above procedure shall not apply where continuous rovings are filament wound at an angle to the pipe axis. Values of circumferential and longitudinal unit modulus for individual layers shall be obtained by reference to Figure 3. Values of circumferential and longitudinal design unit load shall be calculated by application of the factors given in Table 3.NOTE 1 It is possible that more than one combination of layers may 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 construction shall be checked in every case using equation (6).

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

Loss in tensile strength Factor k2

< 20 % 1.2

> 20 % < 50 % Interpolate between20 % = 1.250 % = 2.0

> 50 % Material unsuitable

(2)

ux = d Xx (3)

XLAM = (X1m1n1 + X2m2n3 + ... Xxmxnx) (4)

ULAM = d XLAM (axial direction) (5)

ULAM > Q (6)

e x = u

XxK-----------

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The response of continuous roving wound pipe to biaxial loading applied simultaneously is different from the response when loads are applied independently. To assess the behaviour of combined loads a complete anisotropic stress/strain analysis shall be carried out and the response of the laminate to the combined load examined (see foreword). The normal or shear strain in each layer shall be less than that calculated in 14.4.2.5. If the analysis is not available a biaxial failure envelope shall be constructed as shown in the worked example in Appendix C.NOTE 2 Additional considerations are necessary if the pipework is to be subject to vacuum or external pressure considerations (see clause 17).

15.2 Thickness. Where values of thickness are required in the equations in this section the thickness of the laminate in the region under consideration shall be taken as the sum of the thicknesses of the individual layers making up that laminate.The nominal thickness of each layer, for design purposes, shall be determined from the glass content 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 mm for pipes manufactured with chopped strand mat and 2 mm for filament wound pipes.Abrupt changes in laminate thickness shall be avoided. The blending taper between regions of differing thickness shall be not steeper than 1 in 6.

16 Design calculations for pipes subject to internal pressureNOTE The equations in this section are derived from thin shell theory.

16.1 Pipes subject to internal pressure. The circumferential and axial unit loads Qc and Qa (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 unit load, Qa, 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.

whereM 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).

whereF is the algebraic sum of all the appropriate vertical forces acting on the pipes adjacent to the support.

Vertical forces causing tension in the pipe shall be considered positive, and forces causing compression shall 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 compressive load is adequate to resist collapse by local buckling. To make this check the overall unit modulus, XLAM, (for the axial direction using axial compressive properties) for the proposed construction shall be calculated from equation (4).The permissible maximum axial compressive unit load, Qp, to resist buckling shall then be calculated from equation (11) which includes a safety factor of 4.

The maximum compressive unit load shall in no case exceed the value calculated in equation (6). If in the original design it does, the laminate construction shall be modified, and the necessary calculations repeated until this condition is satisfied.

17 Design calculations for pipes subject to vacuum17.1 Pipes without stiffening rings. The circumferential unit load, Qc, shall be calculated from equation (7).

(7)

(8)

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

Di is the internal diameter (in mm).

Circumferential unit load Qc pDi

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

Axial unit load QapDi

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

(9)

(10)

(11)

Axial unit load Qa = pDi

4----------- 4M

;Di 2

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

Axial unit load QapDi 4

---------- 4M

;Di 2

------------- F;Di----------=

Qp 0.6tXLAM

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

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The maximum direct axial unit load, Qa, shall be calculated from equations (9) or (10) as appropriate. From each of these values the appropriate thickness of laminate shall be calculated and the largest value obtained shall be used for calculations. Using as a basis a laminate construction which satisfies this requirement, the total thickness of the laminate, t, shall be determined as described in 15.2.The composite modulus of the laminate, ELAM (in N/mm

2), shall also be calculated from equation (12).

where

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

If in the proposed design this condition is not fulfilled the design shall be changed either by re-designing the laminate or by providing additional stiffening rings (see 17.2). The calculation shall then be repeated until an acceptable construction is indicated.17.2 Pipes with stiffening rings. If the calculations in 17.1 indicate an unacceptable laminate thickness it may be preferable to re-design the pipe to include stiffening rings.The design of pipes with stiffening rings may be approached by two methods.

a) Method 1. To fix the distance between stiffeners by utilizing the spacing between flanges, anchors, or additional stiffeners and checking the minimum thickness required to prevent collapse by using equations (13) or (14), which includes a safety factor of 4, dependent on the value of the stiffener distance/diameter ratio:

where

b) Method 2. To fix the construction and hence thickness and calculate the required distance between stiffeners from equation (15).

The distance between stiffeners in either case shall not exceed the value of J calculated from equation (15).For a proposed stiffening ring profile and composition it is then necessary to determine the diameter (Ds) of the neutral axis of the stiffening ring. Subsequently it shall be ensured that the second moment of area of the designed stiffening ring, l, is not less than the value obtained from equation (16):

where ELAM has been calculated from equation (12).The permissible length of shell, Js, which may be regarded as effectively contributing to the amount of the stiffening ring section shall be

but in no case shall Js be taken as greater than J.Stiffening rings shall extend completely round the circumference of the pipe and any joints in the stiffener shall be so designed as to develop the full stiffness of the ring.

Section 4. Dimension markings and information

18 Dimensions18.1 Diameters

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

(12)

XLAM is the overall unit modulus of the laminate under consideration determined from equation (4);

t is the total thickness of the laminate.

(13)

(13)

ELAM XLAM

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

tm Do

4p2E

LAM --------------------

0.33=

(14)

J is the distance between the centre line of stiffeners;

Do is the outside diameter = Di + 2t.

(15)

(16)

Js = 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 0.18DoJDs

2p

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

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The manufacturer shall declare the actual internal diameter, in mm, of the pipes and fittings related to the relevant nominal size.18.1.2 uPVC lined pipelines using extruded pipe and moulded fittings. The nominal size of pipe and fittings up to and including 500 shall be based on the nominal size of the extruded pipe (see clause 7).NOTE Account should be taken, on sizing of the system, of any consequential reduction of the bore size below that of unlined pipe.

18.1.3 uPVC lined pipelines using fabricated linings. The nominal size of pipe and fittings above 500 shall be one of the relevant sizes specified in 18.1.1.18.1.4 Polypropylene lined pipelines using fabricated lining. The nominal size of pipe and fittings above 80 shall be one of the relevant sizes specified in 18.1.1.

19 Tolerances on dimensions of pipes and fittings19.1 Diameters. The tolerances on the declared diameter measured at 23 2 C shall be as follows:

1.5 mm for pipes up to and including 150 nominal size; 3 mm for pipes over 150 and up to 600 nominal size; 0.5 % of the declared internal diameter for pipes over 600.

All deviations from roundness, such as ovality, with the exception of pipe deformation due to its own weight, shall be contained within these tolerances.19.2 Length. The tolerances on length shall be as follows:

1.5 mm for cut or fabricated lengths of pipe up to 4 m in length; 3.0 mm for cut or fabricated pipe larger than 4 m in length.

19.3 Squareness of ends. All unflanged pipe shall be cut square with the axis of the pipe to within 3 mm for all nominal sizes up to and including 400 and to within 4 mm for all nominal sizes over 600.

19.4 Deviation from straightness. For pipes of nominal size greater than 150 the deviation from straightness of the bore of the pipe shall not exceed 0.3 % of the effective length of the pipe or 15 mm, whichever is the smaller. Deviation from straightness shall be measured with the pipe in an unstrained vertical position. Measurements shall be taken at four equidistant points around the circumference. The average value of the maximum and minimum vertical distance between a straight edge, or taut chord, touching the ends of a pipe, and the wall of the pipe in the case of a concave curve or, in the case of a convex curve, between a straight edge or taut chord which touches the wall of the pipe and is equidistant from the wall at the two ends of the pipe, and the wall of the pipe at the end, is expressed as a percentage of the effective length of the pipe.19.5 Fittings. Tolerances on angles of fittings shall be 1 for nominal sizes up to 600 and 0.5 for nominal sizes greater than 600.

20 MarkingEach pipe and fitting shall be permanently marked with the following information:

a) manufacturers name or initials and identification 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 if used.

21 Information21.1 The manufacturer shall declare the lining and laminate system to be employed which shall be specified in full including the following details determined at the design stage:

a) lining system;b) number of layers and notional thickness of each layer;c) total minimum thickness of the laminate system;

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 manufacturers 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.Li

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d) composition of each layer, including: 1) type and mass of reinforcement, e.g. chopped strand mat, woven cloth, continuous rovings etc.;2) percentage by mass of fibrous reinforcement;3) type of resin system.

NOTE Information on different methods of manufacture is given in Appendix D.

21.2 The manufacturer shall give recommendations for the installation of pipes and fittings complying with this standard either for above ground or below ground situations.

Section 5. Construction and workmanship

22 Manufacturing conditions in works involving the cure of resinsMaterials shall be stored and used in compliance with the suppliers instructions; reinforcement materials shall be stored dry.Unless a hot curing resin system is being used the temperature of the working area shall be maintained above 15 C for any laminating process and the cure cycle of the resin system. All other laminating work shall be discontinued whenever the air temperature falls to 10 C or the dew point is reached (when condensation occurs).The working area shall be suitably divided into clearly defined sections for preparation of reinforcement, mixing of resins, application, trimming and finishing.

23 Manufacturing procedure23.1 The manufacturer shall eliminate as many variables as possible to ensure consistency in both materials and fabrication, and shall provide adequate supervision at all stages of manufacture.NOTE All operators to be employed should be experienced in carrying out the type of work involved in the order. Representative test pieces of laminate should be submitted to prove the competence of each operator unless evidence of prior satisfactory work is available.

23.2 The requisite amount of resin, catalyst or hardener and any other ingredient such as accelerator or permitted filler, shall be accurately measured and thoroughly mixed. The amounts of mixed resin and reinforcement used in the laminate and the number and type of layers applied shall be recorded where applicable; the records shall be made available to the purchaser or inspecting authority.

23.3 Where hand lay-up is used in the manufacturing procedure, rolling shall be used to consolidate the laminate. Whilst good rolling is essential, the rolling pressure shall not be sufficient to cause disturbance of the distribution of the reinforcement or to break the fibre strands.The manufacturer shall ensure that good adhesion is obtained between successive layers of the laminate either by appropriate scheduling of the manufacturing operation or by removing the surface of the cured resin to expose the fibres.Adjacent pieces of reinforcement shall be overlapped by not less than 50 mm. The edges shall be worked out by brushing with a stippling action and all joints shall be staggered through the thickness of the laminate.Where directionally biased reinforcement is used care shall be taken to ensure that the high strength fibres are adequately aligned in the correct direction to give the required strength.The number, size and distribution of air bubbles, pits or inclusions shall be not greater than previously submitted samples. Acceptable limits of visual defects shall be in accordance with 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 all laminates. An elevated temperature post cure shall be applied where this is required by the design procedures (see 14.4).

24 Thermoplastics liners24.1 If uPVC is the required liner uPVC pipe complying with BS 3505 or BS 3506 shall be used for lining pipe up to 500 mm diameter. In the case of larger pipes uPVC sheet complying with BS 3757 shall be used and this shall be stress relieved in an oven at temperatures between 120 C and 140 C for 15 min from attaining this temperature.All forming operations of uPVC shall be performed at a temperature between 120 C and 140 C.24.2 Polypropylene and PVDF liners if required shall be formed from extruded sheets to which is attached a glass fibre backing. The thickness of the sheet shall be as specified in clause 7.

24.3 All welds shall be butt welds

Before welding of the liner commences the edges to be welded, together with a filler rod, shall be suitably cleaned. In addition, glass backed thermoplastics liners shall have the glass backing stripped back to a distance between 3 mm and 6 mm on either side of the weld preparation to ensure that no glass filaments are included in the welded joint.

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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 the grade of material of the filler rod shall be compatible with the liner material being welded. All edges to be butt welded by filler rod shall be chamfered to give an included angle and a land as shown in Figure 6.24.4 All welds shall be fully penetrating. Welds completed from one side only shall have at least 70 % of the material strength; where there is reasonable access to the weld from both sides the weld shall have at least 85 % of the material strength.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 thermoplastics liners should be required to demonstrate their ability to weld to the requirements of liners to this standard.24.5 The external surface of the weld shall be finished to a smooth contour before laminating and tested by the use of a high frequency spark tester at a voltage of 20 kV 10 %. Any weld that shows evidence of notches, lack of fusion or holes shall be rejected. (See clause 30.)24.6 In the case of flanged pipes the lining material shall be carried over the face of the flange.

25 Fittings25.1 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 used for the pipeline described in Appendix F, shall be calculated from the appropriate method given in Table 7 using the relevant values given in Table 8.NOTE 1 The location of the dimensions in Table 7 and Table 8 are shown in Figure 7 and Figure 8.NOTE 2 The preferred method of manufacture for fittings from 25 to 600 nominal size is by one-piece moulding.25.3 The minimum thicknesses of flanges shall be as given in Table 9. The minimum dimensions of GRP backing flanges and drilling dimensions in accordance with class 150 of BS 1560, class 150 of BS 3293 and Table 10 of BS 4504 shall be as given in Table 10.NOTE The relationships of these dimensions are given in Figure 9 and Figure 10.25.4 Pipe supports shall have a minimum width of 25 mm and a minimum contact arc of 120 on the underside of an above ground pipe.NOTE The frequency of support shall be such that the ratio of deflection to span should not exceed 1 : 300 when the pipe is filled with the process fluid at the design temperature.Piping should be supported and anchored so as to prevent undue loads on connected equipment, and at the same time to permit controlled expansion and contraction between anchors and changes of direction.Anchors should be so designed that the loads are properly transmitted into the wall of the pipe.

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Table 6 Minimum socket depthsNominal size

of pipeMinimum 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

253240506580

100125150200250300350400450500600700800900

1 000

25252536404050606575

100100100100105105110115120135150

25252536404070757575

100100100100105110115120120135150

25252536404070757575

100100105120120125150175200225250

25253236404070757575

100100120135143165200235265300

252540405060707585

110150180220240270300

254040406585

100120135180220270300

5050507595

115145180215285

5875

95150185230290

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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 + L2C C1 + L2 C1 + L3 C1 + A + L2E1 Sd + D/2 Sd + D/2 + L3d Sd + D/2 + AdE2 Sd + d/2 Sd + d/2 + L3D Sd + d/2 + ADL1 L2d + L2D + 2.5 (Dd) L3D + L3D + 2.5 (Dd) AD + Ad + L2D + 2.5 (Dd)

H Hd1 + Hd2NOTE 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 sizeD 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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Table 9 Dimensions of flanges (see Figure 9 and Figure 10)

Stub flange (type A)thickness, NA

Stub flange outside diameter, Da

Flange (type B) thickness, NB

Flange (type C) thickness, NC

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

BS 4504: Table 10.

0.2 % 0.1 %

Pipe nominal size

Pressure up to 10 bar Pressure up to 10 bar

mm mm mm mm mm mm mm mm

253240

232425

10b10b10b

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

26 Joints26.1 General. The types of joints in general use are as follows:

a) butt;b) cemented spigot and socket;c) flanged;d) spigot and socket with elastomeric sealing rings.

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

Selection of the type of pipe joint shall be governed by the duty requirements, details of the pipe construction and economic considerations. In all cases the detail of the joint shall be so designed that the chemical resistance of the joint is acceptable for its application.All joints of types a), b) and c) shall be designed and constructed to take at least the same end load as the pipe.

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

Where the design of a butt joint is developed it shall incorporate an additional design factor of 1.2 the pipe properties.When uPVC is the lining material injection moulded fittings with sockets suitable for solvent cementing may be used and in such cases the following requirements shall apply.

1) uPVC pipe shall comply with either BS 3505 or BS 3506 and sizes shall not exceed 150 nominal size.2) Fittings shall comply with BS 4346-1. The use of moulded stub or full face flange fittings with sockets is not permitted. Flanges shall be as detailed in 26.4.4.3) Solvent cements shall comply with BS 4346-3 and shall be chosen such that the chemical resistance of the joint is suitable for the chemical conditions within the pipe.

Pipe nominal

size

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 10

of BS 4504

Pressure 10 bar O.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

80100125150

10121213

14171718

190229254279

152.4190.5215.9241.3

3/43/47/87/8

19.019.022.222.2

4888

5/85/83/43/4

200220250285

160180210240

18181822

8888

M16M16M16M20

200250300350

15182122

21253031

343406483533

298.4362.0431.8476.2

7/81111/8

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 with class 150 of BS 3293

700800900

1 000

29323539

41454955

927c1 061c1 168c

1 289c

864c978c

1 086c1 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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4) Before application of glass fibre reinforcement, all external steps at the joints shall be blended into the pipe surface with a minimum taper of 1 in 6 using a filled resin paste which shall satisfy the bond shear strength requirement of 12.1.5) The design temperature of systems incorporating injection moulded fittings shall not exceed 40 C and the design pressure shall not exceed 6 bar.

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

NOTE It is recommended that jigs should be used to ensure that butt and cemented joints are aligned and held rigidly in this position during the jointing process. The position of the pipes should be maintained until the joint has adequate mechanical strength.

26.3 Lined pipe. The joint shall be so constructed that only the liner comes in contact with the fluid. In the case of flanged pipes the lining material shall be carried over the face of the flange. In the case of butt joints the thermoplastics liners shall be joined by welding.

26.4 Joint types

26.4.1 Butt joints in unlined pipes. The ends of the pipe shall be chamfered back at a slope of 1 in 6 leaving intact the chemical resistant inner laminate. The surface of the pipe to be overlaid shall be freshly abraded to remove the resin-rich surface and expose the glass fibre over an area extending 25 mm beyond the joint overlay. The chemically resistant resin cement shall be applied to the ends of the pipe with the pipes butted and fixed in position (see Figure 11). The space between the two chamfered surfaces shall be filled to a depth of at least 3 mm using the resin cement. The initial layer, of minimum width 50 mm over the chamfered surfaces shall consist of a laminate of chopped strand mat and the specified resin.In the case of type 1 and type 3 pipes (see 12.2) the minimum total mass of chopped strand mat shall be 900 g/m2 which shall be applied in at least two layers. The glass content of the laminate shall be between 25 % and 33 % when determined by the method described in BS 2782:Method 1002.

In the case of type 2 pipes (see 12.2) the minimum mass of chopped strand mat shall be 600 g/m2 and have a glass content between 25 % and 33 % when determined by the method described in BS 2782:Method 1002.The joint shall be overlaid with suitable laminates such that the hoop, axial and inter-laminar sheer strengths of the joint shall be at least equal to the strength of the pipe.The length of the overlay for pipes up to and including nominal size 100 shall be not less than the values given in Table 10. For pipes with nominal size greater than 100 the overlay length shall be calculated from the equations (18) or (19).

where

An outer-layer of chopped strand mat shall be provided, together with an outer resin-rich layer.The outer edges of the overlay shall taper down to the pipe so that they do not form stress raisers. When practicable the interior of the joints shall be freshly abraded to remove the glass finish and sealed with a minimum of 900 g/m2 chopped strand mat followed by a surface tissue layer and sealing coat. This internal laminate shall not be considered as making a contribution to the strength of the joint. The pipe manufacturer shall provide precise details of the laminate to be used for the joint and shall provide full test evidence that illustrates that a joint so produced is satisfactory.26.4.2 Butt joints in lined pipes. The ends of the pipe shall be chamfered back at a slope of 1 in 6 leaving intact the thermoplastics liner (see Figure 6). The liner shall be prepared for welding as specified in 24.3, fixed in position and welded. The bond strengths between the area adjacent to the weld and the overlay shall comply with 12.1. The initial overlay using 600 g/m2 of chopped strand mat shall have a glass content of between 25 % and 33 % when determined by the method described in BS 2782:Method 1002.The joints shall then be overlaid with a suitable laminate such that the hoop axial and inter-laminar shear strengths of the joint shall be at least equal to the strength of the pipe.The length of the overlay for pipes up to and including 100 nominal size shall be not less than the appropriate 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)

ULAM is determined in the axial direction.

Overlay length2KULAM

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

orDi 2------ whichever is the greater

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For pipes of nominal size greater than 100 the overlay length shall be calculated from equations (18) or (19), whichever is the greater, where ULAM is determined in the axial direction.An outer layer of chopped strand mat shall be provided, together with an outer resin rich layer.The outer edges of the overlay shall taper down to the pipe so that they do not form stress raisers. The pipe manufacturer shall provide precise details of the laminate to be used for the joint and shall provide full test evidence that illustrates that the joint so produced is satisfactory.

Table 11 Minimum butt joint overlay lengths including taper

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

a) In all cases the hoop axial and interlaminar shear strength of the socket joint shall be at least equal to the hoop axial and interlaminar strength of the pipe.b) The depth of the socket shall be equal to or greater than the appropriate value given in Table 5 always provided that the design strain limitation is observed, or as calculated from equation (20), whichever gives the greater value.

whereULAM is in the axial direction

c) The manufacturer shall provide a cement that is suitable for the process conditions for which the pipe is intended.d) The joint shall be designed so that the thickness of the cement is between 0.15 mm and 1.5 mm.

e) The bond between the pipe, socket and cement shall have a minimum strength of 7 N/mm2. The type test to prove conformance shall be carried out by the method described in BS 5350-C5 using double overlap joints as test pieces.f) The manufacturer shall state the minimum ambient conditions required for the bonding cement to cure and provide precise details of the method of assembly and proof of suitability.g) When practicable the interior of the joints shall be freshly abraded to remove glass and shall be sealed with a laminate containing a minimum of 900 g/m2 chopped strand mat which shall be covered by a surface tissue layer and sealing coat.

26.4.4 Flanged joints

26.4.4.1 General. Flanged joints are classified according to type as follows.

Type A: stub flange with backing flange (see Figure 9).Type B: full faced flange with or without thermoplastics liner (see Figure 10).Type C: full faced flange with or without thermoplastics liner with backing flange (see Figure 10).

For pipe systems which have a test pressure above 16 bar only stub flanges with loose steel backing flanges shall be used.Full faced flanges shall not be used for mating to raised face flanges.Prototype testing shall be carried out on all flange designs to show that the flanged joint will seal under the combined force of maximum design pressure plus an applied bending moment, Mt, determined from equation (21).

whereULAM is determined in the axial direction.

Unless there are records of satisfactory operating performance each flange design shall be proved by test. The test pressure on flanged joints of nominal size up to 600 shall be 6 the rated pressure for the pipes with a pressure rating up to 10 bar.26.4.4.2 Manufacturing tolerances. All flanges shall comply with the following.

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

up to and including 450 nominal size 1 mm deviation;

above 450 nominal size1.5 mm deviation.

Nominal size of pipe

Minimum length of overlay for various design 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 depthULAMK

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

(21)Mt = ; 4----- ULAM

pDi 4

---------- Di

2 1.3

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The back faces of flanges shall be smoothed flat and shall be parallel to the flange face.b) Squareness. Flanges shall be square to the pipe or fittings to within 1 up to 100 nominal size and to within 0.5 above 100 nominal size.

26.4.4.3 Assembly. Manufacturers recommendations on the sequence of tightening bolts and nuts shall be followed. If the maximum torque is specified the threads of all bolts and nuts shall be greased.

26.4.5 Socket and spigot joints with elastomeric sealing ringsNOTE Socket and spigot joints are primarily designed for use with underground pipes but, in general, are not suitable if end loads have to be transmitted through the pipe.

Alternative designs of joints making provision for end loads are available.

26.4.5.1 Joint quality. When used the socket and spigot joint shall be at least equal to the pipe in quality and performance, excluding axial properties.At the test pressure, the joint shall not leak in the following conditions:

a) angular deflection;b) draw;c) misalignment;d) diameter distortion;e) combination of a) to d).

The elastomeric sealing ring shall comply with BS 2494, and shall be free from substances that can have a detrimental effect on the pipe material and contents.The elastomeric sealing ring shall have suitable chemical resistance and the volume swelling shall not exceed 20 % after immersion in the process fluid for 4 weeks at the temperature of intended use.26.4.5.2 Joint requirements. For pressure pipe the following joint requirements shall be met when gauge pressures of 0.1 bar and 1.5 nominal pressure of the pipe, measured at the top of the pipe, are maintained for 30 min.

For non-pressure pipe the following joint requirements shall be met when gauge pressures of 0.1 bar and 1.5 bar, measured at the top of the pipe, are maintained for 30 min.

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

3 for pipes of nominal size equal to or less than 500;2 for pipes of nominal size greater than 500 and up to and including 900;1 for pipes of nominal size greater than 900 and up to and including 1 000.

The manufacturers shall advise the angular deflection permissible at installation.b) Draw. The joint shall withstand without leakage a minimum draw of 0.25 % of the maximum pipe length, in addition to angular deflection.c) Misalignment. The joint shall withstand misalignment without leakage when a force of 20 N/mm of internal diameter, Di, is applied. For this maximum misalignment the compression of the elastomeric sealing ring shall remain within limits appropriate to the type of ring used.d) Diameter distortion. When the barrel of the pipe (excluding the socket) has reached a maximum diameter distortion of 5 % of the nominal diameter, the resultant ovality in the joint shall not allow leakage. In no case shall the distortion load exceed that given in c).e) Combination of joint requirements. The joint shall withstand a combination of angular deflection, draw, misalignment, and diameter distortion as indicated in a), b), c) and d) above.

Section 6. Testing

27 Tests for design27.1 General. Manufacturers shall demonstrate their ability to design and/or produce satisfactory pipes and fittings for the specified duty. If acceptable documentary evidence of past experience is not available, prototype pipe shall be made and tested.NOTE The prototype tests may be witnessed by the purchaser or inspecting authority.

27.2 Manufacture of prototype pipes and fittings. Prototype pipes and fittings shall be as follows:

a) the pipes and fittings shall be identical in design and manufacture to the proposed production pipe;

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b) the length of the test pipe shall be at least 1 500 mm or 5 pipe nominal size, whichever is greater;c) the prototype test assembly shall incorporate features 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 test shall be representative of the maximum designed free installation length.

27.3 Tests to be applied to prototype pipes and fittings. Where the proposed pipe system is designed so that the pipes are not subjected to end load in service, provision shall be made in the test to avoid incurring end loads. The tests shall demonstrate resistance to specific modes of failure and shall include one or more of the following appropriate to the intended service conditions.

a) Strain determination test. Determination of general and local strains by measurement (using strain gauges or other suitable methods) when the pipe is hydrostatically pressurized to the design pressure.b) Fatigue test. Determination of the fatigue strength of the pipe and/or fitting by cyclic variations of pressure between limits.NOTE The test fluid should be preferably the process fluid.

c) Short term burst pressure test. Determination of the factor of safety to failure and the mode of failure by hydrostatically pressurizing the pipe until failure occurs.d) Buckling test under negative internal pressure. Determination of the resistance to collapse under negative pressure. The length of the test pipes shall be as specified in item d) of 27.2.

All pipes and fittings shall be adequately supported during 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 strain shall not exceed 0.26 % when the pipe is tested hydrostatically to at least 1.3 times the design pressure strain.b) Fatigue test. The pipe shall withstand 10 times the estimated number of pressure cycles required in the life of the pipe.c) Short term burst pressure test. The pipe shall withstand a pressure at least K (see 14.4) times the rated pressure without bursting, and weepage shall not occur below a pressure of 0.75 K rated pressure.NOTE To determine the burst pressure it is permitted to use a 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 bar gauge whichever is the lower pressure.

27.5 Records of tests. Records of all prototype tests shall be retained by the manufacturer and shall be made available to the purchaser and inspecting authority as required.27.6 Chemical tests. Chemical resistance tests shall be done whenever there is no previous experience of the process conditions. The test specimens used shall be representative of the pipe as produced.27.7 Additional tests. Additional tests such as the heat distortion temperature test, mechanical properties of the laminate, abrasion or bond strength between lining and laminates shall be carried out where previous experience is not documented.

28 Production testing28.1 General. The frequency at which production pipes are to be tested shall be agreed at the tender stage.NOTE It is recommended that a minimum of 10 % of pipes and fittings should be hydrostatically pressure tested at the manufacturers works.

28.2 Dimensional requirements. The dimensions of test pieces shall be as follows.

a) Diameters, lengths and straightness shall be within the specified tolerances given in clause 19. Due care shall be taken to avoid the effect of self-weight of the pipe or fitting.b) Flatness of flange faces and alignment to pipe shall be within the tolerances given in 26.4.4.2.NOTE Flatness of flanges should be assessed only after all the reinforcement has been applied and the resin has cured.

28.3 Surface finish. The pipes and fittings shall be inspected for surface defects and comply with Appendix E.28.4 Cure. The extent of cure of the laminate shall be tested by determining the Barcol hardness in accordance with the method described in BS 2782:Method 1001 which shall be within 10 % of the resin manufacturers published value. The acetone extract shall not exceed the resin manufacturers recommendation.28.5 Hydrostatic testing. Pipes shall be hydrostatically tested to 1.3 times the design pressure. The test pressure shall be applied and maintained for a sufficient time to permit a thorough examination to be made of the pipe but in any case for not less than 1 h. Any indication of leakage or excessive strain shall be cause for rejection.

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NOTE Care should be taken to ensure that the test pressure is not exceeded during hydrostatic testing. Over-pressurization may lead to laminate damage which is irreparable and would be cause for rejection of the pipe.

28.6 Examination after pressure testing. On completion of the pressure test the pipe and/or fitting shall be inspected internally and externally. Any indication of cracking, resin crazing, or excessive strain shall be cause for rejection. Where practicable pipes with thermoplastics linings shall be spark tested after completion of testing; any evidence of cracking or weld defect shall be cause for rejection.

29 Welding procedure tests for thermoplastics liningsThe test pieces shall incorporate 300 mm long butt welds made by joining two pieces of the material to be used for the lining, each 300 mm long and 125 mm wide. The weld shall be made in the same way as the production welds and shall include at least one stop and start in each run. Welding procedure for the test welds shall be in accordance with clause 24.After completion, the test weld shall be examined visually and by the use of a high frequency spark tester giving a minimum peak voltage of 20 kV. Any weld showing evidence of notches, lack of fusion or pinholes shall not be used for tensile testing.Test pieces shall be machined from the welded sample and subjected to the tensile test described in B.8. The tensile strength across the weld shall be not less than 70 % or 85 % of the tensile strength of welded sheet as appropriate to the type of weld (see 24.4).NOTE If any test weld shows evidence of notches, lack of fusion or pinholes or the tensile strength requirements of 24.4 are not met, the welding procedure should be modified or the welder receive further training, as appropriate, until all test welds are satisfactory.

30 Tests for production welds in thermoplastics liningsAll production welds shall be examined