BS 6464 (1984) Reinforced Plastics Pipes, Fittings and Joints for Process Plants

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BRITISH STANDARD

BS 6464:1984 Incorporating Amendment No. 1

Specification for

Reinforced plastics pipes, fittings and joints for process plants

Confirmed January 2009 UDC 621.643.2:678.067.5:66.026

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BS 6464:1984

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 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 Agrément Greater London Council Heating and Ventilating Contractors’ Association Institute of Plumbing Ministry of Agriculture, Fisheries and Food Pitch Fibre Pipe Association of Great Britain

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/9 Draft for comment 76/50861 DC ISBN 0 580 13776 7

Amendments issued since publication Amd. No.

Date

Comments

6294

November 1990

Indicated by a sideline in the margin

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BS 6464:1984

Contents Page Committees responsible Inside front cover Foreword iii Section 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 3 10 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 8 19 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 18 28 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 on receipt 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

Page 36 37

Appendix F Pipework fabrication methods Figure 1 — Limits of pressure and diameter Figure 2 — Relationship between thickness and glass content for laminates 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 46 Figure 12 — Test piece for the determination of shear strength of bond between thermoplastics lining and laminate 46 Figure 13 — Test piece for the determination of lap shear strength of laminate 47 Figure 14 — Test for the determination of peel strength of bond between thermoplastics liner and laminate 48 Figure 15 — Test piece for the tensile strength of thermoplastics sheet 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 reinforced laminate layers 4 Table 3 — Factors to be applied to design unit load of continuous rovings 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 used in equations of Table 7 13 Table 9 — Dimensions of flanges 14 Table 10 — Thickness and mating dimensions of flanges and 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

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 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 had amendments incorporated. This will be indicated in the amendment table on the inside front cover. © BSI 03-1999

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BS 6464:1984

Section 1. General

2 Definitions

1 Scope

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

This 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.

2.1 curing2) the chemical reaction resulting in the final polymerized product NOTE 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 structure NOTE 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, Ú the angle of the application of continuous rovings with respect to the horizontal axis

3 Nomenclature, symbols and units for design Several 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.

NOTE 2 The titles of the publications referred to in this standard are listed on the inside back cover. 1)

1 bar = 105 N/m2 = 100 kPa.

2)

These definitions differ from those given in BS 1755-1.

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BS 6464:1984

The following additional symbols with their terms are used in the design calculations: K k1 k2 k3 k4 k5 nx mx ux Xx ºx º ºd ºR

overall design factor determined from the equation (1), factor relating to method of manufacture, factor relating to long term behaviour, factor relating to temperature, factor relating to cyclic loading, factor relating to curing procedure, number of layers of type x in construction under consideration, mass of reinforcement per unit area (kg/m2 glass) in one layer of type x, design unit loading [N/mm {per kg/m2 glass}] for a selected layer of type x, unit modulus of a selected layer of type x [N/mm {per kg/m2 glass}] allowable strain for each type of reinforcing material, allowable strain, determined from resin properties, maximum design strain, strain to failure of the unreinforced resin determined by the method described in Method 320C of BS 2782:Method 320 A to F:1976.

Section 2. Materials and properties 4 Thermosetting resin systems NOTE 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 manufacturer’s 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.

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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 have a surface treatment compatible with the resin.

6 Aggregates and fillers The 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 liners If 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 joints The 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.

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BS 6464:1984

Table 1 — Derivation of definitions relating to symbols Term

Definition

Derivation

Symbol

Unit

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

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

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

N/mm (per kg/m2 glass)

Unit modulus

The ratio of the load per unit Obtained from the width per unit mass of glass to measured load at 0.2 % the corresponding direct strain in a tensile test. strain, in a loaded tensile test piece.

X

N/mm (per kg/m2 glass)

ULAM UOVL

N/mm width

Laminate design The load permitted to be unit loading 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.

Unit load

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

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

9 Mechanical properties The 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 Ú 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.

N/mm width

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 Filament winding angle to axis

Circumferential factor

0° < Ú < 15°

0

1

15° < Ú < 75°

0.5

0.5

75° < Ú < 90°

1

0

Ú

Longitudinal factor

10 Thermal properties The 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. © BSI 03-1999

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BS 6464:1984

Table 2 — Minimum mechanical properties of reinforced laminate layers 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 cloth square woven

250

16 000

6.0

biased woven less than 5.1 : 1 major direction minor direction

430 90

23 000 10 000

6.0 6.0

baised woven equal or more than 5.1 : 1 major direction

450

25 000

6.0

500

28 000

6.0

Continuous rovings

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 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 liner NOTE 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. 4

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 Flammability Where 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.

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BS 6464:1984

Section 3. Design and design calculations

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

14 General

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.

14.1 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 design NOTE 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.

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14.3 Conditions for design

14.3.3 Design vacuum NOTE 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). K = 3 × k1 × k2 × k3 × k4 × k5

(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 Method of manufacture

Part factor k1

Handwork 1.5 Repeatable machine controlled work 1.5 Spray application 3.0

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BS 6464:1984

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 Factor k2

Loss in tensile strength

< 20 %

1.2

> 20 % < 50 %

Interpolate between 20 % = 1.2 50 % = 2.0

> 50 %

Material unsuitable

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 manufacturer’s 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, º, for each type of resin system shall be 0.1ºR 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.

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14.4.2.4 The allowable strain for each type of reinforcing material shall be calculated from equation (2). u e x = ----------Xx K

(2)

ux = ºd Xx

(3)

14.4.2.5 Considering all the constituent parts in 14.4.2.2 to 14.4.2.4 the allowable design strain, ºd, 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 thickness 15.1 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). XLAM = (X1m1n1 + X2m2n3 + ... Xxmxnx)

(4)

The laminate design unit loading ULAM shall be calculated from equation (5). ULAM = ºd XLAM (axial direction)

(5)

The above procedure shall not apply where continuous rovings are filament wound at an angle ± Ú 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). ULAM > Q

(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.

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BS 6464:1984

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 pressure NOTE 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). pD

Circumferential unit load Q c = -----------i 2

(7)

pD Axial unit load Q a = -----------i 4

(8)

where p

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

Di is the internal diameter (in mm). 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; © BSI 03-1999

c) bending moments due to mass of contents; d) bending moment due to any other external source. pD i 4M Axial unit load Q a = ----------± ------------2 4 ;D i

(9)

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). pD 4M F Axial unit load Q a = ----------i ± ------------- ± ---------2 4 ;D i ;D i

(10)

where F 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. 0.6tX LAM Q p = --------------------------4D i

(11)

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 vacuum 17.1 Pipes without stiffening rings. The circumferential unit load, Qc, shall be calculated from equation (7).

7

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BS 6464:1984

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/mm2), shall also be calculated from equation (12). X LAM E LAM = ---------------t

(14) where J

is the distance between the centre line of stiffeners;

Do is the outside diameter = Di + 2t. b) Method 2. To fix the construction and hence thickness and calculate the required distance between stiffeners from equation (15).

(12) (15)

where XLAM

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

t

is the total thickness of the laminate.

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. 0.33 4p t m = Do  --------------------  2E 

(13)

LAM

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:

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): 2

0.18D o JD s p l = --------------------------------------E LAM

(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 Js = 0.75 √(Dot)

(17)

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 Dimensions 18.1 Diameters 18.1.1 Unlined pipelines. The nominal size of pipes and fittings shall be one of the following values:

(13)

8

25

32

40

50

150

200

250

300

600

700

800

900

65

80

100

125

350 400

450

500

1 000

© BSI 03-1999

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BS 6464:1984

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 fittings 19.1 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 Marking Each pipe and fitting shall be permanently marked with the following information: a) manufacturer’s 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 Information 21.1 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 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.

© BSI 03-1999

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BS 6464:1984

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 resins Materials shall be stored and used in compliance with the supplier’s 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 procedure 23.1 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.

10

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 liners 24.1 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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BS 6464:1984

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.

© BSI 03-1999

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 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.

11

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BS 6464:1984

Table 6 — Minimum socket depths Nominal size of pipe

Minimum socket depth at various pressures Up to 2.5 bar mm

25

32 40 50 65 80 100 125 150 200 250 300 350 400 450 500 600 700 800 900 1 000

12

25 25 25 36 40 40 50 60 65 75 100 100 100 100 105 105 110 115 120 135 150

4 bar mm

25 25 25 36 40 40 70 75 75 75 100 100 100 100 105 110 115 120 120 135 150

6 bar mm

25 25 25 36 40 40 70 75 75 75 100 100 105 120 120 125 150 175 200 225 250

10 bar mm

25 25 32 36 40 40 70 75 75 75 100 100 120 135 143 165 200 235 265 300 —

16 bar mm

25 25 40 40 50 60 70 75 85 110 150 180 220 240 270 300 — — — — —

25 bar mm

25 40 40 40 65 85 100 120 135 180 220 270 300 — — — — — — — —

40 bar mm

50 50 50 75 95 115 145 180 215 285 — — — — — — — — — — —

64 bar mm

58 75 95 150 185 230 290 — — — — — — — — — — — — —

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BS 6464:1984

Table 7 — Equations for calculating fittings dimensions Dimension

Fabrication method Method 1

Method 2

Method 3

B

R + L2

R + L3

R + A + L2

C

C1 + L2

C1 + L 3

C1 + A + L2

E1

Sd + D/2

Sd + D/2 + L3d

Sd + D/2 + Ad

E2

Sd + d/2

Sd + d/2 + L3D

Sd + d/2 + AD

L1

L2d + L2D + 2.5 (D–d)

L3D + L3D + 2.5 (D–d)

AD + Ad + L2D + 2.5 (D–d)

H

Hd1 + Hd2

NOTE 1 NOTE 2

Subscripts D and d refer to the values for the related diameter of each branch. For location of dimensions see Figure 7 and Figure 8.

Table 8 — Minimum separation dimensions to be used in equations of Table 7 All dimensions in millimetres. A

Nominal size

D or d

C1

H

R

S

L2

L3

25 40 50 80

150 150 150 175

50 50 75 100

100 100 125 125

75 115 150 225

75 75 75 75

50 50 50 50

75 75 75 75

100 150 200 250

200 225 275 300

125 100 125 100

150 200 225 250

300 225 300 250

75 125 150 200

50 75 75 75

100 125 175 200

300 350 400 450

350 400 450 475

125 150 175 175

275 325 350 375

300 350 400 450

225 275 300 350

75 100 100 100

225 275 325 350

500 600 700 800

500 500 500 550

200 225 275 325

400 450 525 575

500 600 700 800

375 450 525 600

100 100 100 100

375 450 350 400

900 1 000

600 650

350 400

625 675

900 1 000

675 750

100 100

450 500

© BSI 03-1999

13

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BS 6464:1984

Table 9 — Dimensions of flanges (see Figure 9 and Figure 10) Stub flange (type A) thickness, NA Design strain

0.2 %

Pipe nominal size

0.16 %

0.13 %

Stub flange outside diameter, Da 0.1 %

Pressure up to 10 bar mm

mm

mm

b

mm

mm

mm

mm

— — —

— — —

— — —

50 65

10 10

10 10

10 11

12 13

102 121

80 100 125 150

10 14 15 16

11 15 16 17

12 16 17 18

14 18 19 20

200 250 300 350

18 22 26 26

20 24 29 29

22 26 31 31

400 450 500 600

28 30 31 35

30 32 34 38

33 35 36 40

43 46 50 54

mm

10b 10b 10b

107 127

28 30

— —

133 172 194 219

142 162 192 218

32 32 32 32

— — — —

24 28 34 34

276 337 406 448

273 328 378 438

38 45 50 55

— — — —

36 38 39 44

511 546 603 714

489 539 594 695

55 60 60 65

— — — —

BS 3293: Class 150

BS 4504: Table 10

47 50 55 59

829 937 1 045 1 159

— — —

Pressure up to 10 bar

23 24 25

Pressure up to 6 bar

a

0.2 %

— — —

39 42 47 50

0.1 %

BS 4504: Table 10.

— — —

36 39 43 46

Flange (type C) thickness, NC

BS 1560: Class 150

25 32 40

700 800 900 1 000

Flange (type B) thickness, NB

810 917 1 017 1 124

Pressure up to 6 bar

55 60 65 70

— — — —

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

14

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BS 6464:1984

Table 10 — Thickness and mating dimensions of flanges and backing flanges (see Figure 10) Pipe Backing flange nominal thicknessa, W size Pressure 10 bar Solid

Splitb

mm

mm

Outside diameter and drilling information in accordance with class 150 of BS 1560 O.D

P.C.D.

mm

mm

Hole diameter

Bolts Number

in

— — — 14 14

115 125 134 152 178

79.4 5/ 8 88.9 5/8 98.4 5/8 120.6 3/4 139.7 3/4

15.9 15.9 15.9 19.0 19.0

4 4 4 4 4

80 100 125 150 200 250 300 350

10 12 12 13 15 18 21 22

14 17 17 18 21 25 30 31

190 229 254 279 343 406 483 533

152.4 190.5 215.9 241.3 298.4 362.0 431.8 476.2

19.0 19.0 22.2 22.2 22.2 25.4 25.4 28.6

4 8 8 8 8 12 12 12

28.6 31.8 31.8 34.9

16 16 20 20

400 450 500 600

24 25 27 32

34 35 38 45

Pressure 6 bar

700 800 900 1 000

29 32 35 39

a Based on b Two-part c

41 45 49 55

597 635 698 813

7/ 7

8

/8 7/ 8

1 1 11/8 11/

539.8 8 577.8 11/4 635.0 11/4 749.3 13/8

927c 864c 1 061c 978c 1 168c 1 086c 1 289c 1 200c

13/8 15/8 15/8 15/8

34.9 41.3 41.3 41.3

26 Joints 26.1 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. 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.

© BSI 03-1999

Hole diameter

mm

mm

mm

/2

115 140 150 165 185

85 100 110 125 145

14 18 18 18 18

4 4 4 4 4

M12 M16 M16 M16 M16

5/ 8 5 /8 3/ 4 3 /4 3/ 4 7 /8 7/ 8

200 220 250 285 340 395 445 505

160 180 210 240 295 350 400 460

18 18 18 22 22 22 22 22

8 8 8 8 8 12 12 16

M16 M16 M16 M20 M20 M20 M20 M20

565 615 670 780

515 565 620 725

26 26 26 30

16 20 20 20

M24 M24 M24 M27

895 840 1 015 950 1 115 1 050 1 230 1 160

30 33 33 36

24 24 28 28

M27 M30 M30 M33

Size 1

1/ 2 1 /2 5 /8 5 /8

1 1 11/8 11/4 11/4

Bolts Number

Size

Dimensions and drilling in accordance with class 150 of BS 3293

rubber gaskets with a seating stress of 2.32 N/mm2. split flanges. These values are metric conversions.

NOTE 1

P.C.D

in

— — — 10 10

3/ 4 3/ 4

O.D.

mm

25 32 40 50 65

Outside diameter and drilling information in accordance with Table 10 of BS 4504

28 28 32 36

11/4 11/2 11/2 11/2

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.

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BS 6464:1984

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. 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

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.

16

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

(18)

D or ------i whichever is the greater 2

(19)

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. 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.

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BS 6464:1984

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 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

25 32

100 100

100 100

100 100

100 100

100 100

40 50

100 100

100 100

100 100

100 100

100 100

65 80

150 150

150 150

150 150

150 150

150 150

100

150

150

150

150

150

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. U LAMK Socket depth = -----------------------------------------------------Lap shear strength

(20)

where ULAM 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.

© BSI 03-1999

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). pD 2 ; M t = ----- U LAM –  ----------i D i × 1.3 4 4

(21)

where ULAM 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 size 1.5 mm deviation.

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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 rings NOTE 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 design 27.1 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.

© BSI 03-1999

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 testing 28.1 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 manufacturer’s 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 manufacturer’s published value. The acetone extract shall not exceed the resin manufacturer’s 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 linings The 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 linings All production welds shall be examined visually and by high frequency spark test equipment (20 kV ± 10 %) at the stages specified below: 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 primer or reinforcement is applied to the weld area and a temporary earthing strip shall be provided behind the weld. This strip shall be removed after spark testing.

20

Any defective areas, other than isolated pinholes, in the first run, shall be removed and shall be suitably repaired and again spark tested to the satisfaction of the inspection authority before fabrication continues. Where adjacent defects are less than 15 mm apart they shall be treated as a single, large defect.

31 Production samples for mechanical tests on a laminate 31.1 General. Test pieces shall, when possible, be taken from waste areas provided that they are typical of the laminate they represent. Where this method is impracticable test pieces shall be laid up by the operator at the same time, with the same materials and in the same manner as the item they represent, and cured under the same conditions as the main laminate. 31.2 Mechanical properties of laminates. The following tests shall be carried out to verify the material 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 thermoplastics lining 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 the necessary test pieces for the tests specified. If the testing is to be done at his own works the manufacturer shall supply the necessary labour and appliances. Failing facilities at his own works the manufacturer shall arrange for the tests to be made elsewhere. When required by the order or drawing, test pieces shall be made available for test in the purchaser’s laboratories. When specified all tests shall be witnessed by the inspecting authority and due notice shall be given by the manufacturer to permit compliance.

33 Certification of inspection and testing In case of joint responsibility for the inspection and testing of pipes and fittings signed documentary evidence of the results of all the completed inspections and tests shall be forwarded to the inspecting authority responsible for witnessing the final tests, prior to the conduction of these tests.

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Upon satisfactory completion of the order the organizations responsible for design, construction and inspection shall furnish duplicate copies of a certificate to the purchaser, stating that the design, construction and testing comply with the requirements specified in this standard. Where applicable the actual tests results obtained shall be stated on or with the certificate. NOTE Inspection should include the following stages as appropriate: a) inspection of workshop conditions where manufacture will be carried out; b) inspection of works records relating to the control and issue of materials, resin mixing, etc.; c) identification of the materials of construction and their storage conditions; d) approval of welding procedures and welders; e) witnessing of spark tests on welds in thermoplastics linings where 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 pressure testing, and before any pigmented coatings are applied. Where it is required to use transmitted light during inspection, agreement should be reached between the purchaser and the manufacturer on the stage for applying any pigmented coating.

© BSI 03-1999

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Appendix A Information to be given with an enquiry or tender or on receipt of order The information detailed below is to be given with an enquiry or tender or on receipt of order as appropriate. 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 its reinforcement); 2) resin systems to be used; 3) form(s) of reinforcement including type, number and arrangement of individual layers including any 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 rich layer) 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 inspection f) 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 for pipes and fittings in reinforced plastics. Tests are specified for the determination of the following properties: a) internal shear strength of bonding cement; b) ultimate tensile unit strength of laminate and laminate layers; c) unit modulus of laminate and laminate layers; d) lap shear strength of laminate; e) shear strength of bond between thermoplastics lining and laminate;

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f) peel strength of bond between thermoplastics lining and laminate; g) tensile strength of thermoplastics sheet and welds. NOTE Recommended methods for tests to determine the following properties when required are as follows: water absorption: BS 2782:Method 430B electrical properties:

BS 2044

cure of resin (Barcol hardness):

BS 2782:Method 1001

B.1.2 Accuracy of testing equipment. Testing machines shall be calibrated in accordance with BS 1610 and shall be maintained to grade A. Extensometers, including ancillary or autographic equipment, shall be calibrated in accordance with BS 3846 and shall satisfy at least grade E requirements. B.2 Internal shear strength of bonding cement B.2.1 Test pieces. Lap joints shall be assembled from laminates, 100 mm min. × 25 ± 1 mm × 3 mm min. thick, of equivalent resin reinforcement system to the socket and spigot materials and cement to give a minimum cement layer between laminates of 25 ± 1 mm × 12.5 ± 0.5 mm × 1.5 mm max. thick. The assembly shall be carried out in accordance with the cement manufacturer’s instructions. The ends of the laminates that are clamped to the tensile machine shall be built up to ensure the force is applied along the cemented joint. Three test pieces shall be tested. B.2.2 Conditioning and temperature of test. The test pieces shall be conditioned at 20 ± 5 °C for not less than 3 h immediately before testing. The test shall be carried out at 20 ± 5 °C. B.2.3 Procedure. Measure the cross-sectional area of the cemented part of the joint. Clamp the test piece in the serrated jaws of a suitable tensile testing machine so that the jaws grip the built up faces of the end pieces and the test pieces are in axial alignment with the direction of pull. Apply a force to the test piece by separating the jaws at a constant rate between 5.0 mm/min and 6.5 mm/min. Record the maximum force at which the joint fails. Test pieces which fail within the laminate or at the laminate/cement interface shall be disconnected and the test shall be repeated, unless the calculated shear strength is greater than that specified in clause 8. B.2.4 Calculation. Calculate the internal shear strength, Sc, for each test piece from equation (22). F S c = -----Ac

(22)

where F

is the maximum force (in N);

Ac

is the cross-sectional area of the cemented joint.

B.2.5 Report. The test report shall include the following: a) identification of the laminate structure; b) identification of the cement; c) conditioning temperature of the test pieces; d) individual test results; e) date of the test. B.3 Ultimate tensile unit strength of laminate and laminate layers NOTE

The tests for ultimate tensile unit strength and unit modulus (see B.4) may be combined using the same test pieces.

B.3.1 Test pieces. The form and number of test pieces shall be as described in BS 2782:Method 1003 for type II or type III specimens. B.3.2 Conditioning and temperature of test. The test pieces shall be conditioned at 20 ± 5 °C for not less than 3 h immediately before testing. The test shall be carried out at 20 ± 5 °C. B.3.3 Procedure. Measure the mean width of the test piece to the nearest 0.05 mm and number of laminate layers. © BSI 03-1999

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Clamp the test piece in the serrated jaws of a suitable tensile testing machine so that the jaws grip the entire faces of the end pieces and the test piece is in axial alignment with the direction of pull. Apply a force to the test piece by separating the jaws at a constant rate such that fracture occurs in 0.5 min to 1.5 min. Report the maximum force applied. Results obtained on test pieces that break within the area of the end pieces shall be disregarded and additional test pieces tested. B.3.4 Calculation. Calculate the ultimate tensile unit strength u (in N/mm per kg/m2 glass) from equation (23). Fmax u = --------------------b n x mx

(23)

where Fmax b nx mx

is the maximum force (in N); is the width of test piece (in mm); is the number of laminate layers in the test piece; is the mass of glass (in kg/m2) in one layer of laminate in the test piece.

B.3.5 Report. The test report shall include the following: a) identification of the laminate or laminate layers; b) conditioning temperature of the test pieces; c) when necessary, the direction of the major axes of the test specimens in relation to the direction of some feature of the material from which they were cut; d) whether the faces of the test pieces where machined; e) ultimate tensile unit strength of the material, reported as the arithmetic mean of the ultimate tensile unit strengths of the test pieces; f) date of the test. B.4 Unit modulus of laminate and laminate layers B.4.1 Principle. The unit modulus shall be calculated from a determination of the tensile force necessary to produce in the test piece an extension of 0.10 mm on a length of 50 mm (0.2 % strain). B.4.2 Test pieces. The form and number of test pieces shall be as described in BS 2782:Method 1003 for type II and type III specimens. B.4.3 Conditioning and temperature of test. The test pieces shall be conditioned at 20 ± 5 °C for not less than 3 h immediately before testing and the test carried out at 20 ± 5 °C. B.4.4 Procedure. Measure the mean width of the test pieces to the nearest 0.01 mm and count the number of laminate layers. Clamp the test piece in axial alignment with the direction of pull between the jaws of a suitable tensile testing machine. Clamp an extensometer on the test piece. The extensometer shall be of a type that will measure extension over a length of 50 ± 1 mm of the test piece to an accuracy of at least 0.0025 mm. Apply a small initial tensioning force f to the test piece for the purpose of straightening it. (This force should be not greater than 10 % of the expected force at 0.2 % strain.) With this initial force on the test piece, set the indicating device to zero. Increase the force steadily by separating the jaws at a rate of 1 mm/min ± 25 %, until the increase in extension indicated by the extensometer reaches 0.1 mm. Note the force, F, on the test piece at this extension. If the test is also to be used for the determination of ultimate tensile unit strength the extensometer should be removed as quickly as possible and the test continued as required by B.3.

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B.4.5 Calculation. Calculate the unit modulus X (in N/mm per kg/m2 glass) from equation (24) or (25) F–f X x = ------------------------------------0.002 b n x mx F–f or X LAM = -------------------

0.002 b

(24) (25)

where F f b nx mx

is the force required to produce 0.2 % strain (in N); is the force applied to straighten the test piece initially (in N); is the test piece width (in mm); is the number of laminate layers in the test piece; is the mass of glass (in kg/m2) in one layer of laminate in the test piece.

In cases where it is expected that 0.2 % strain may give rise to danger of fracture of the test piece, it is permissible to carry out the test at 0.1 % strain (corresponding to an extension of 0.05 mm over a 50 mm gauge length). The initial force shall be correspondingly smaller, and the unit modulus (in N/mm per kg/m2 glass) shall be calculated from equation (26) or (27). F–f X x = -------------------------------------0.001 b n x mx F–f or X LAM = -------------------

0.001 b

(26) (27)

B.4.6 Report. The test report shall include the following: a) identification of the laminate; b) conditioning temperature of the test pieces; c) percentage strain at which the unit modulus was determined; d) when necessary, the direction of the major axes of the test pieces in relation to the direction of some feature of the material from which they were cut; e) unit modulus of the material, reported as the arithmetic mean of the unit modulus of the test pieces; f) individual test results; g) date of the test. B.5 Lap shear strength of laminate B.5.1 Test pieces.Test pieces shall conform to the dimensions and shape given in Figure 13. They shall have a minimum thickness of 3 mm and the overall length of the test pieces may be varied to accommodate the requirements of the available testing equipment. The edges of the test pieces shall be smooth but not rounded or bevelled. Two parallel saw cuts, one in each opposite face of the test piece and 12.5 mm apart, shall be sawn across the entire width of the test piece and shall be parallel within 0.8 mm (see Figure 13). The depth of saw cuts shall be half laminate thickness plus the thickness of one layer, or half laminate thickness + 0.1, – 0 mm if the number of layers or the thickness per layer is unknown. Saw cuts shall be as narrow as possible. If the laminate is made entirely from chopped strand mat or by spraying five test pieces shall be tested. If the laminate contains woven rovings or other directional reinforcement 10 test pieces, five parallel with each principal axis of anisotropy, shall be tested. B.5.2 Conditioning and temperature of test. The test pieces shall be conditioned at 20 ± 5 °C for not less than 3 h immediately before testing. The test shall be carried out at 20 ± 5 °C. B.5.3 Procedure. Clamp the test piece in the jaws of the tensile testing machine and axially align the test piece with the direction of pull. Apply a force to the test piece by separating the jaws at a constant rate of between 5.0 mm/min and 6.5 mm/min. Record the maximum force at which separation of the layers occurs. Test pieces that fail prematurely or at an obvious flaw shall be discarded and retests made.

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NOTE

A shear-type failure with some peeling at the interlaminar bond should result.

B.5.4 Calculation. Calculate the lap shear strength, Ss, for each test piece from equation (28). FS s = -----ab

(28)

where F a b

is the maximum force (in N); is the distance between saw cuts (in mm); is the width of test piece (in mm).

B.5.5 Report. The test report shall include the following: a) identification of the laminate; b) conditioning temperature of the test pieces; c) lap shear strength of the laminate reported as the arithmetic mean of the lap shear strengths of the test pieces; d) individual test results; e) date of the test. B.6 Shear strength of bond between thermoplastics lining and laminate B.6.1 Test pieces. The test piece shall be cut from the full thickness of the external laminate and lining and shall be of the form and dimensions shown in Figure 12. Three test pieces shall be used. B.6.2 Conditioning and temperature of test. The test pieces shall be conditioned at 20 ± 5 °C for not less than 3 h immediately before testing. The test shall be carried out at 20 ± 5 °C. B.6.3 Procedure. Make two thin saw cuts at right angles to the major axis 20 mm apart, symmetrically about the transverse centreline on the test piece. One cut shall be through the full thickness of the thermoplastics material but not into the laminate, the other shall be through the full thickness of the laminate but not into the thermoplastics material. Measure the cross-sectional area between the saw cuts. Clamp the test piece in the serrated jaws of a suitable tensile testing machine and axially align with the direction of pull. Apply a force to the test piece by separating the jaws at a constant rate of 25 ± 6 mm/min. Record the maximum force at which separation of the layers occurs. If the test piece breaks other than at the interface and the calculated shear strength is less than that specified in clause 8 the test shall be repeated. If the repeat test fails the bond strength shall be recorded as failed. B.6.4 Calculation. Calculate the shear strength of the bond from the maximum force and the area under shear and express in N/mm2. B.6.5 Report. The test report shall include the following: a) identification of the liner/laminate; b) conditioning temperature of the test pieces; c) individual test results and the position of failure; d) date of the test. B.7 Peel strength of bond between thermoplastics lining and laminate B.7.1 Test pieces. The test piece shall be cut from the full thickness of the laminate and lining and shall be of the form and dimensions shown in Figure 14. Five test pieces shall be tested. B.7.2 Conditioning and temperature of test. Test pieces shall be conditioned at 20 ± 5 °C for not less than 3 h immediately before testing. The test shall be carried out at 20 ± 5 °C. B.7.3 Procedure. Make a saw cut at one end of the test piece at the interface of the laminate and thermoplastics material across the width of the test piece and for 20 mm along its length. The saw cut shall include, as far as possible, equal amounts of laminate and thermoplastics material. 26

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Clamp the laminate horizontally in the jaws of a vice or clamp and apply a force to the thermoplastics lining by means of weights until the force is just sufficient to peel the lining from the laminate. During this operation ensure that the plane of the force remains normal to the laminate/thermoplastics interface (see Figure 14). B.7.4 Calculation. Calculate the peel strength of the bond from the total force at peel and the measured width of the test piece, and express in newtons per millimetre width. B.7.5 Report. The test report shall include the following: a) identification of the lining/laminate; b) conditioning of the test pieces; c) bond peel strength of the thermoplastics lining/laminate combination reported as the arithmetic mean of the bond peel strengths of the test pieces; d) individual test results; e) date of the test. B.8 Tensile strength of thermoplastics sheet and welds B.8.1 Test pieces. The test piece from sheet shall be of the shape and dimensions shown in Figure 15 and the full thickness of the sheet. The test piece of a weld shall be of the shape and dimensions shown in Figure 14. Three test pieces shall be used for either test. B.8.2 Conditioning and temperature of test. The test pieces shall be conditioned at 20 ± 5 °C for not less than 3 h immediately before testing. The test shall be carried out at 20 ± 5 °C. B.8.3 Procedure. Measure the mean width and thickness to the nearest 0.02 mm. Clamp the test piece at the widened ends or insert plugs if available and mount in the tensile testing machine in axial alignment with the direction of pull. Apply a force to the test piece by separating the grips at a constant rate of 25 ± 6 mm/min until it breaks, the range of the testing machine being such that the maximum force falls between 15 % and 85 % of the maximum scale reading. B.8.4 Calculation. Calculate the tensile strength, B, for each test piece of the sheet and welded sheet from equation (29). F B = ---A

(29)

where F A

is the maximum force (in N); is the original cross-sectional area (in mm2).

Calculate the arithmetic mean of the three results from each test and express the average value for the welded test pieces as a percentage of the average value for the sheet test pieces. B.8.5 Report. The test report shall include the following: a) identification of the thermoplastics sheet; b) individual results and arithmetic mean of the tensile strength of the sheet; c) individual results and arithmetic mean of the tensile strength of the weld; d) percentage tensile strength of the weld compared with that of the sheet; e) date of the test.

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Appendix C Worked examples of the design method specified in section 3 C.1 General. The design method in this standard, being based on unit loadings, is particularly suited to the design of laminar constructions. Correctly applied, the method ensures that each layer of the composite carries the proportion of the total load appropriate to its strength, and that nowhere in the composite laminate excessive strains can occur that might lead to local debonding and subsequent service failure. The results of many tests done on resin/glass fibre composites have shown that both the ultimate tensile load and the unit modulus values obtained are proportional to the mass of glass reinforcement contained in the laminate layer. For each of these properties a single value may, therefore, be utilized over the full range of glass contents normally used for each type of reinforcement (see Table 2), and the design calculations are thus considerably simplified. The thickness of a laminate layer is also very largely controlled by the mass of glass specified and the glass content, being subject to only small variation resulting from manufacturing technique. Layer thicknesses for given glass contents and masses may be obtained from Figure 2. C.2 Example: Pipe design for internal pressure without vacuum C.2.1 Design criteria. Consider the design for a pipe having an internal diameter of 1 000 mm and for an internal pressure of 5 bar (0.5 N/mm2). The pipe is assumed to be manufactured by hand lay-up for any chopped strand mat and woven roving constructions, (k1 = 1.5), and machine controlled for continuous rovings construction, (k1 = 1.5). In addition the following assumptions will be made: a) the long term behaviour, k2 = 1.2; b) the cyclic stressing 104 for the life of the pipe, k4 = 1.4; c) full post cure will be used, k5 = 1.1. For the purpose of the illustration two operating temperatures will be considered with resins being required with different heat distortion temperatures. The circumferential unit load calculated from equation (7) = 250 N/mm. Therefore the laminate shall be designed so that its design strength is not less than this calculated value [see equation (6)]. For the purposes of these examples it is assumed that the axial load, Qa, does not exceed Qc so that a laminate designed to withstand the latter will be satisfactory. C.2.2 Design constructions C.2.2.1 All chopped strand mat (CSM) construction. For this construction the operating temperature is assumed as 60 °C, the heat distortion temperature of the resin to be used is 100 °C and its fracture strain is 3.5 %. a) Determine the design factor K [see equation (1)]. K = 3 × k1 × k2 × k3 × k4 × k5 = 3 × 1.5 × 1.2 × 1.0 × 1.4 × 1.1 = 8.3 b) Determine the allowable design strain. Allowable resin strain (see 14.4.2.3) º = 0.1ºR = 0.1 × 3.5 = 0.35 % As this is greater than 0.2 % this latter value is taken as the allowable resin strain. Allowable laminate strain [see equation (2)]. u e x = -----------

Xx K

200 × 100 = ------------------------------14000 × 8.3

= 0.17 %

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The allowable design strain, ºd, is taken as the least of these = 0.17 % c) Determine the laminate construction. Overall unit modulus [see equation (4)]. XLAM = Xmn = 14 000 mn Laminate design unit loading [see equation (5)]. ULAM = ºdXLAM 0.17 = ------------- × 14000 × m × n 100

The design requirement is satisfied if ULAM is at least equal to the circumferential unit load [see equation (6)]. hence 0.17 × 140 × m × n = 250 m × n = 10.5 kg/m2 glass Thus a suitable construction of laminate would be as follows [see Figure 16(a)]: resin rich inner layer with tissue

—

2

two layers of 300 g/m (one at each surface)

0.6 kg/m2

sixteen layers of 600 g/m2

9.6 kg/m2

one layer 450 g/m2

0.45 kg/m2

resin rich outer layer with tissue

— 10.65 kg/m2

C.2.2.2 Chopped strand mat and woven roving construction. In practice a large proportion of laminates are not all CSM and they incorporate woven rovings. A simple form of this type of construction is shown in Figure 16(b) where alternate layers of woven roving complying with the requirements of BS 3749 (800 g/m2 ) and CSM (450 g/m2 ) are used. For the calculation an operating temperature of 80 °C is assumed and a dual resin system will be used with the following properties. Property

Resin A

Fracture strain Heat distortion temperature

B

2.5 % 1.75 % 125 °C 100 °C

The method of calculation is as follows. a) Determine the design factor K [see equation (1)]. K = 3 × k1 × k2 × k3 × k4 × k5 = 3 × 1.5 × 1.2 × 1.25 × 1.4 × 1.1 = 10.4 b) Determine the allowable design strain. Allowable resin strain (see 14.4.2.3). Resin A = 0.1 × 2.5 = 0.25 % Resin B = 0.1 × 1.75 = 0.175 % As the value for resin B is less than 0.2 % its value (i.e. 0.175 %) is the allowable resin strain.

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Allowable laminate strain [see equation (2)]. Chopped strand mat (CSM): U CSM 200 × 100 & CSM = ------------------= ------------------------------------ = 0.137 % XCSMK 14000 × 10.4

Woven rovings (WR): U X WRK

250 × 100 WR e WR = ---------------- = ------------------------------------ = 0.141 % 16000 × 10.4

The allowable design strain, ºd, is taken as the least of these = 0.137 %. c) Determine the laminate construction. The resin A is selected to form an inner corrosion resistant laminate (2 × 600 g/m2 ) and as the resin for the resin rich inner and outer layers with tissue. If the number of layers of woven rovings is n, the number of CSM (450 g/m2) is n – 1. These are in addition to the corrosion resistant laminate and the usual CSM (300 g/m2) laminate under the outer resin rich layer. Laminate design unit loading (in N/mm) [see equation (5)]. U LAM = e d XLAM 0.137 = ---------------- (2 × 0.6 × 14000 + 0.45 × 14000 × 100

× (n– 1) + 0.8 × 16000 × n) As this value shall be at least equal to, Qc, i.e. 250 N/mm n = 9.01 say 10. Thus a suitable construction of laminate would be as follows [see Figure 16b)].  resin rich inner layer with tissue Resin A  two layers of 600 g/m2 CSM    Resin B   

ten layers of 800 g/m2 WR alternate with nine layers 450 g/m2 CSM one layer 300 g/m2 CSM

Resin A

resin rich outer layer with tissue

— 0.6 kg/m2 8.0 kg/m2 4.1 kg/m2 0.3 kg/m2 — 13.0 kg/m2

C.2.2.3 Chopped strand mat and continuous rovings construction. In this construction the continuous roving laminates are laid by a machine controlled process between a CSM (2 × 600 g/m2) corrosion resistant laminate and a CSM (450 g/m2) under the outer resin rich layer [Figure 16c)]. One type of resin as in C.2.2.1 is considered. a) Determine the design factor [see equation (1)]. Chopped strand mat (CSM): K = 3 × k1 × k2 × k3 × k4 × k5 = 3 × 1.5 × 1.2 × 1.0 × 1.4 × 1.1 = 8.3 Continuous rovings (CR): K = 3 × 1.5 × 1.2 × 1.0 × 1.4 × 1.1 = 8.3

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b) Determine the allowable design strain. Allowable resin strain (see 14.4.2.3) º = 0.1 ºR = 0.1 × 3.5 = 0.35 % As this is greater than 0.2 % this latter value is taken as the allowable resin strain. Allowable laminate strain [see equation (2)] u CSM: & x = -----------

XxK

200 × 100 = --------------------------------- = 0.17 % 14000 × 8.3

CR:

u & x = -----------X xK 550 × 100- = 0.24 % = -------------------------------28000 × 8.3

The allowable design strain, ºd, is taken as the least of these = 0.17 %. c) Determine the laminate construction. Assume the continuous rovings are laid at an angle of 55° to the pipe axis with a mass per layer of 600 g/m2 and n laminates are used. Circumferential unit modulus of the laminate construction [see equation(4)]. XLAM(c) = 14000 × (2 × 0.6 + 0.45) + 9900 × 0.6 × n The design requirement is satisfied if XLAM(c) is at least equal to the circumferential unit load [see equation (6)]. 0.17- (14000 × (2 × 0.6 + 0.45) + Hence -----------100

+ 9900 × 0.54) × 0.6 × n) = 250 n = 41.73 say 42 Thus a suitable construction of laminate would be as follows: resin rich inner layer with tissue two layers of CSM (600 g/m2) 42 layers CR (600 g/m2) laid at 55° one layer of CSM (450 g/m2) resin rich outer layer with tissue

— 1.2 kg/m2 25.2 kg/m2 0.45 kg/m2 — 26.85 kg/m2

Because this pipe does not have similar properties in circumferential and axial directions, the allowable loading in the axial direction should now be checked. 0.17 ULAM(a) = ------------ (14000 × (1.2 + 0.45) + 100

+ 4500 × 0.54) × 0.6 × 42) = 136 N/mm. Provided the axial load does not exceed 136 N/mm, the above laminate will be satisfactory. If this is not the case then the allowable axial loading will have to be increased to the design value by further application of additional layers of chopped strand mat, woven rovings or continuous rovings.

4)

Factor relating to angle of lay (see Table 3).

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If circumferential and axial loads are applied simultaneously it is necessary to establish whether the allowable loads under these conditions are less than those in the above calculation. This may be done by the construction of a biaxial failure envelope (see Figure 17) using information obtained from the physical testing of the proposed laminate. The following conditions are applied: 1) if Qc > 0 and Qa > 0 or if Qc < 0 and Qa < 0 then Uc = ULAM(c) and Ua = ULAM(a) or 2) if Qc > 0 and Qa < 0 or if Qc < 0 and Qa > 0 then Uc = ULAM(c) × (1 – Ua/ULAM(a)) and Ua = ULAM(a) × (1 – Uc/ULAM(c)) Where Ua and Uc are the allowable axial and circumferential unit loads under biaxial loading. The completed biaxial failure envelope shows the combinations of loads which may be applied to the laminate, for example, from Figure 17, a combined load of Ua = 80 N/mm and Uc = 160 N/mm would be satisfactory but a combination of Ua = – 80 N/mm and Uc = 160 N/mm would not be satisfactory. C.2.3 Thickness calculations. If we assume a glass content of 30 % for CSM, 50 % for woven rovings and 65 % for continuous rovings Figure 2 gives the thicknesses expected for these constructions for a resin density of 1.3 as follows: CSM: 2.2 mm per kg/m2 glass. WR: 1.2 mm per kg/m2 glass. CR: 0.85 mm per kg/m2 glass. Therefore the thicknesses of the laminates (excluding surface reinforced gel coats) in the three constructions are as follows. a) The all CSM construction of example C.2.2.1 requires a total mass of 11.25 kg/m2 glass and the design thickness of this laminate is calculated as: 2.2 × 10.65 = 23.4 mm b) The mixed CSM/WR construction of example C.2.2.2 will have a design thickness: for CSM layers (1.2 + 0.3 + 9 × 0.45) × 2.2

= 12.2 mm

for WR layers 10 × 0.8 × 1.2

= 9.6mm

total design thickness

= 21.8 mm

c) The mixed CSM/CR construction of example C.2.2.3 will have a design thickness: for CSM layers (1.2 + 0.45) × 2.2

= 3.6 mm

for CR layers 0.6 × 42 × 0.85

= 21.4 mm

total design thickness

= 25.0 mm

C.3 Example: pipe design for vacuum with internal pressure C.3.1 Design laminate construction. Assume for the purpose of this example that example C.2.2.2 has a vacuum duty of full vacuum in addition to 5 bar pressure. Since the internal pressure duty is greater than the vacuum duty the pipe will be strong enough for the membrane forces. It is, therefore, only necessary to consider buckling. The design laminate construction for C.2.2.2 is: 5.55 kg/m2 CSM + 8.0 kg/m2 WR having a total thickness of 21.8 mm. Unit modulus of laminate: XLAM = 5.55 × 14000 + 8.0 × 16000 = 205700 N/mm 32

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Composite modulus [from equation (12)] XLAM 2 205700 E LAM = -------------- = --------------------- = 9436 N/mm t 21.8

Substituting in equation (13) and assuming that the pipe is infinitely long, the necessary minimum thickness, tmin, to prevent buckling is: 4 × 0.1 0.33 1043.6  -------------------------- = 29.94 mm  2 × 9436

This thickness is greater than the thickness required for pressure, therefore, construction needs modifying (see C.3.2) or stiffening rings are required (see C.3.3). C.3.2 Thickness calculation without stiffeners. The selected construction is to be in the form 1 200 g/m2 CSM + (n – 1) layers of 450 g/m2 CSM + n layers of 800 g/m2 WR + 300 g/m2 CSM. Therefore to satisfy the required thickness: (1.2 + 0.3) × 2.2 + (n – 1) × 0.45 × 2.2 + + n × 0.8 × 1.2 = 29.94 n = 14.16 say 15 Since the composite modulus varies with construction it is necessary to recheck the laminate unit modulus to ensure that it is > 9803 N/mm2 i.e.: XLAM = (1.2 + 0.3 + 14 × 0.45) 14000 + + 15 × 0.8 × 16000 = 301200 N/mm t = (1.5 + 14 × 0.45) × 2.2 + (15 × 0.8) × 1.2 = 31.56 mm X LAM 2 301200 E LAM = -------------- = --------------------- = 9544 N/mm t 31.56

Since the modulus of the revised laminate construction is greater than the earlier modulus the proposed construction is satisfactory. The laminate construction required to satisfy a full vacuum design consideration is therefore as follows. Resin rich inner  Resin system A  surface 2 × 600 g/m2 CSM Woven roving (BS 3749) 450 g/m2 CMS 300 g/m2 CMS



15 layers  14 layers 

 Resin system B 

Resin rich outer surface Using the revised values of Do (1000 + 2 × 31.56 mm) and ELAM (9544 N/mm2) it is necessary to recheck the thickness, tmin. This gives a value of 30.38 mm which is less than the original, t, and therefore the laminate construction is satisfactory. C.3.3 Thickness calculation with stiffeners. The laminate required for pressure may be suitable for full vacuum if stiffeners are added. Using equation (15) the required spacing of stiffeners, J, is given by: 21.8 2.5 9436 × 1043.6 J = --------------------  × --------------------------------------- = 3882 mm  1043.6  0.4 × 4 × 0.1

Under the requirements of 21.2 the stiffening rings should have a minimum second moment of area determined from equation (16). Assume the diameter of the neutral axis is 1 100 mm and the composite modulus, E, is that of CSM: 2 X 14000 E CSM = ------------- = ------------------ = 6364 N/mm t CSM 2.2

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The required second moment of area is, therefore, 2

6 4 0.18 × 1043.6 × 3882 × 1100 × 0.1 l = ------------------------------------------------------------------------------------------------------ = 13.86 × 10 mm 6364

Considering equation (17), the length of pipe that may be considered as contributing to the stiffness of the ring is: Js = 0.75 (1043.6 × 21.8)0.5 = 113.1 mm

Appendix D Methods of manufacture of reinforced plastics pipes D.1 General. In the case of contact moulded pipes and some filament pipes it is possible to start with PVC or polypropylene tubes which act as formers during the manufacturing process and provide a chemical resistant liner in service. For chemical plant applications it is essential that the inside layers in the pipe wall have good resistance to the process liquors and protect the main structure of the pipe. To achieve this in pipes without thermoplastics liners a special laminate construction for the inner layer is specified. This consists of a gel coat of the selected chemical resistant resin reinforced with a tissue of C glass or suitable synthetic fibre backed by two layers of 600 g/m2 chopped strand mat with a glass content of 25 % to 30 %. It is essential that the glass content in this layer does not exceed 30 %. D.2 Contact moulding NOTE

Contact moulded pipe is the most widely used GRP in the British chemical industry.

D.2.1 Unlined pipe. In this process the resin and reinforcement ring is applied to mandrels by hand lay-up or by some form of mechanical application. The amount and type of glass put into the construction of the laminate can be varied to suit any specific mechanical design requirement. Rolling is generally employed to consolidate the resin and glass and to remove air. This process is done carefully so that the reinforcement is not disturbed and the glass fibre strands are not broken. The pipe is left on the mandrels until the resin has cured sufficiently to allow the pipe to be handled and the mandrel removed. D.2.2 Pipe with thermoplastics liners. The lining materials in common use are uPVC and polypropylene. In the case of uPVC, pipe is available which is suitable for liners up to 500 mm. For pipe diameters greater than 500 mm the liners are formed from sheet and welded. For lined pipe to be successful it is necessary to promote a good bond between the thermoplastics lining and the resin laminate. In the case of uPVC this is achieved by chemically bonding to the uPVC surface. In the case of polypropylene or PVDF sheet used to form the tube it is supplied with a layer of woven glass fibre for bonding purposes. The thermoplastics liners form the mandrel for the contact moulding operation to proceed as in D.2.1. D.3 Filament winding with continuous rovings D.3.1 Construction D.3.1.1 General. Filament wound GRP pipes are normally produced by winding specifically orientated resin impregnated glass fibre continuous rovings on a mandrel, and there are two basic construction methods for the structural thickness in current use, as follows: a) biaxial construction; b) helically wound construction. In both types of construction, there is incorporated an inner layer and an interior layer consisting respectively of a smooth resin-rich surface reinforced with surfacing tissue of glass, polyester or acrylic fibre and a resin-rich corrosion resistant layer reinforced with glass fibres. D.3.1.2 Biaxial construction. This method of construction consists of applying circumferentially and longitudinally disposed glass fibres such that the corresponding circumferential and longitudinal strength and stiffness of the finished pipe meets with design requirements. This type of construction can be manufactured on any type of filament winding machine, either by a discontinuous process employing a series of mandrels or a proprietory continuous machine.

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D.3.1.3 Helically wound construction. In this method of construction the glass is not wound around the mandrel at right angles to the pipe axis but a guide for the glass rovings is moved to and fro along the mandrel so that the fibres are in a helix around the pipe. This type of pipe is produced only by a discontinuous process using conventional lathe type machines employing solid or collapsible mandrels. D.4 Reinforced plastics matrix pipe. This type of pipe is made in a similar manner to that described in D.3.1.2, the differences being that special aggregate and filler are added in a predetermined sequence. D.5 Centrifugal moulding. In this process, resin, glass and fillers are introduced into a rotating mould to produce the designed pipes. Pipes so produced have a fixed outside diameter.

Appendix E Acceptable limits of visual defects The acceptable limits of visual defects are as given in Table 12. Table 12 — Acceptable limits of visual defects Defects

Liner

Non-liner

Blisters

None

Maximum 5 mm diameter, 1 mm high

Chips

None

Maximum 6 mm but shall not penetrate the surface

Cracks

None

None

Crazing

None

Slight

Discoloured areas None (due to high exotherm or contamination)

None

Dry spots

None

10/m2 with no individual spot greater than 100 mm2

Entrapped air

None at surface

Maximum 3 mm diameter and no more than 10/500 mm2

Exposed glass

None

None

Exposed cut edges

None

None

Foreign matter

None

None

Pits

Maximum 3 mm diameter, 0.5 mm Maximum 3 mm diameter, 1.5 mm deep, 100/m2 deep, 100/m2

Scores

Maximum 0.2 mm deep

Maximum 0.5 mm deep

Sharp discontinuity

Nominal size up to and including 200 : 1 mm; nominal size between 201 and 400 : 1.5 mm; nominal size over 400 : 2.0 mm

Nominal size up to and including 200 : 1 mm; nominal size between 201 and 400 : 1.5 mm; nominal size over 400 : 2.0 mm

Surface porosity

None

None

Wrinkles

Maximum deviation 20 % of wall Maximum deviation 20 % of wall thickness thickness but not exceeding 3 mm but not exceeding 4 mm

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Appendix F Pipework fabrication methods Pipework fabrication methods are as given in Table 13. Table 13 — Pipework fabrication methods Method

1

Factory workshop

Minimum separation dimensions for workshop fabricated sub-assemblies. Manufacture, by techniques not requiring full butt joints, of pipework sub-assemblies of convenient size and shape for transport to site. The minimum separation dimensions to be used with the sub-assemblies, method 1, is given by the equations in Table 7 using values given in Table 8. The terminal ends of the sub-assemblies may be flanged or may be suitable for butt jointing after preparation on site in accordance with 26.4.1 and Figure 11 in accordance with 26.4.2 and Figure 6. For terminal ends the dimensions for method 2 are to be used.

Site, including site workshop where appropriate

Erection/assembly of the sub-assemblies to form pipework systems. Flanged joints and butt joints to be made where appropriate.

NOTE This procedure is commonly known as the “thin skin technique” whereby a sub-assembly is generally produced from pre-formed thin shells which are integrally laminated together to produce the final sub-assembly.

2

3

36

Minimum dimensions for but jointed pipes and fittings. Manufacture of pipe lengths and pipe fittings (including flanges) which have ends suitable for butt jointing after preparation on site to the requirements of 26.4.1 and Figure 11 or the requirements of 26.4.2 and Figure 6. The minimum dimensions of the pipe fittings are given by the equation in Table 7 using the values in Table 8. Minimum dimensions for flanged pipes and fittings. Manufacture of pipe lengths and pipe fittings complete with flanged ends. The minimum dimensions of the pipe fittings are given by the equations in Table 7 using the values in Table 8.

Erection/assembly of the pipe lengths and pipe fittings to form pipework systems. Flanged joints and butt joints to be made where required. Erection/assembly of the pipe lengths and pipe fittings to form pipework systems. Flanged joints to be made where required.

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Figure 1 — Limits of pressure and diameter

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38 Figure 2 — Relationship between thickness and glass content for laminates with resin of relative density, (+), 1.1 to 1.3

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Figure 3 — Relationship of unit modulus to winding angle

Figure 4 — Factor related to temperature

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Figure 5 — Factor related to cyclic loading

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Figure 6 — Butt joint build-up for lined pipe

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Figure 7 — Pipework shapes for fabrication methods 1 and 2 (see Appendix F)

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Figure 8 — Flanged pipe fittings for method 3 (see Appendix F)

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Figure 9 — Typical stub flanges (type A)

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

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NOTE Amount of overlay, t2 ’ is a laminate having 1.2 times the UTUS of pipe wall liminate, t1. All dimensions in millimetres.

Figure 11 — Butt joint build-up for unlined pipe

Figure 12 — Test piece for the determination of shear strength of bond between thermoplastics lining and laminate

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Figure 13 — Test piece for the determination of lap shear strength of laminate

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Figure 14 — Test for determination of peel strength of bond between thermoplastics liner and laminate

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Figure 15 — Test piece for tensile strength of thermoplastics sheet and welds

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Figure 16 — Typical examples of laminate construction

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Figure 17 — Biaxial failure envelope

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Licensed copy: Mr. National University Singapore, National University of Singapore, Version correct as of 19/11/2012 08:31, (c) The British Standards Institution 2012

BS 6464:1984

Publications referred to BS 476, Fire tests on building materials and structures. BS 476-7, Surface spread of flame tests for materials. BS 1560, Steel pipe flanges and flanged fittings (nominal size 1/2 in to 24 in) for the petroleum industry. BS 1560-2, Metric dimensions. BS 1610, Method for the load verification of testing machines. BS 1755, Glossary of terms used in the plastics industry. BS 1755-1, Polymerization and plastics technology. BS 2044, Laboratory tests for resistivity of conducting and antistatic rubbers. BS 2494, Materials for elastomeric joint rings for pipework and pipelines. BS 2782, Methods of testing plastics. BS 2782-Method 121A, Determination of temperature of deflection under a bending stress of 1.8 MPa of plastics and ebonite. BS 2782-Method 320A to F, Determination of tensile strength, elongation and elastic modulus. BS 2782-Method 345A, Determination of compressive properties by deformation at constant rate. BS 2782-Method 430B, Determination of water absorption at 23 °C with allowance for water-soluble matter. BS 2782-Method 1001, Measurement of hardness by means of a Barcol impressor. BS 2782-Method 1002, Determination of loss on ignition. BS 2782-Method 1003, Determination of tensile properties. BS 3293, Carbon steel pipe flanges (over 24 in nominal size) for the petroleum industry. BS 3396, Woven glass fibre fabrics for plastics reinforcement. BS 3496, E glass fibre chopped strand mat for the reinforcement of polyester resin systems. BS 3505, Unplasticized PVC pipe for cold water services. BS 3506, Unplasticized PVC pipe for industrial purposes. BS 3532, Unsaturated polyester resin systems for low pressure fibre reinforced plastics. BS 3534, Epoxide resin systems for glass fibre reinforced plastics. BS 3691, Glass fibre rovings for the reinforcement of polyester and of epoxide resin systems. BS 3749, Woven roving fabrics of E glass fibre for the reinforcement of polyester resin. BS 3757, Specification for rigid PVC sheet. BS 3846, Methods for the calibration and grading of extensometers for testing of metals. BS 4346, Joints and fittings for use with unplasticized PVC pressure pipes. BS 4346-1, Injection moulded unplasticized PVC fittings for solvent welding for use with pressure pipes, including potable water supply. BS 4346-3, Specification for solvent cement. BS 4504, Flanges and bolting for pipes, valves and fittings. Metric series. BS 4504-1, Ferrous. BS 5350, Methods of test for adhesives. BS 5350-C5, Determination of bond strength in longitudinal shear. BS 5350-C6, Determination of bond strength in direct tension in sandwich panels. BS 5480, Specification for glass reinforced plastics (GRP) pipes and fittings for use for water supply or sewerage5). BS 5955, Code of practice for plastics pipework (thermoplastics materials). BS 5955-7, Recommended methods for thermal fusion jointing.

5) Referred

to in the foreword only.

© BSI 03-1999

Licensed copy: Mr. National University Singapore, National University of Singapore, Version correct as of 19/11/2012 08:31, (c) The British Standards Institution 2012

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