BS-7336-1990.pdf

BRITISH STANDARD BS 7336:1990 Specification for Polyethylene fusion fittings with integral heating element(s) for use with polyethylene pipes for the conveyance of gaseous fuels Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 13:38:23 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 7336:1990 This British Standard, having been prepared under the direction of the Plastics Standards Policy Committee, was published under the authority of the Board of BSI and comes into effect on 31 July 1990 © BSI 12-1999 The following BSI references relate to the work on this standard: Committee reference PLM/9 Draft for comment 89/46089 DC ISBN 0 580 18740 3 Committees responsible for this British Standard The preparation of this British Standard was entrusted by the Plastics Standards Policy Committee (PLM/-) to Technical Committee PLM/9, upon which the following bodies were represented: British Board of Agrément British Gas plc British Plastics Federation British Plumbing Fittings Manufacturers Association British Valve and Actuator Manufacturers Association Department of the Environment (Building Research Establishment) Department of the Environment (Construction Industries Directorate) Department of the Environment (Property Services Agency) Department of Transport Electricity Supply Industry in England and Wales Engineering Equipment and Materials Users Association Health and Safety Executive Institute of Building Control Institution of Civil Engineers Institution of Gas Engineers Institution of Production Engineers Institution of Water and Environmental Management 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 Society of British Gas Industries Society of British Water Industries Water Companies Association Water Research Centre Water Services Association of England and Wales The following bodies were also represented in the drafting of the standard, through subcommittees and panels: Institute of Plumbing Ministry of Agriculture, Fisheries and Food Standards Association of Australia Amendments issued since publication Amd. No.Date of issueComments Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 13:38:23 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 7336:1990 © BSI 12-1999i Contents Page Committees responsibleInside front cover Forewordiii 1Scope1 2Definitions1 3Materials2 4General requirements for fittings2 5Individual types of fittings or connections4 6Long-term dimensional stability of individual fittings10 7Performance requirements for jointed pipe-to-fitting assemblies13 8Marking and information15 9Packaging16 Appendix A Preparation of test piece assemblies17 Appendix B Conditioning23 Appendix C Methods for determination of dimensions23 Appendix D Method of test for coupler assembly force and joint integrity subject to angular deflection24 Appendix E Method of test for pressure loss for in-line tees and elbows26 Appendix F Method of test for pressure drop through a tapping tee29 Appendix G Assessment of fitting resistance tolerance band30 Appendix H Determination of fitting cooling times31 Appendix J Method of test for crush strength32 Appendix K Peel test for fused socket joints34 Appendix L Methods of test for resistance to hydrostatic pressure38 Appendix M Method of test for resistance to accelerated relaxation and end load (AREL test)38 Appendix N Method of test for resistance to pull-out of jointed assemblies following accelerated relaxation39 Appendix P Method of test for resistance to pull-off of fused branch saddle joints39 Appendix Q Method of test for impact resistance of tapping tees40 Appendix R Specification for electrofusion control equipment43 Appendix S Guidance on quality control testing45 Appendix T Recommendations for sampling and testing PE electrofusion fittings and joints46 Appendix U References50 Figure 1 Example designations for tee fittings3 Figure 2 Socket and coupler dimensions5 Figure 3 Control of pipe penetration8 Figure 4 Orientation of terminal shrouds8 Figure 5 Terminals and shrouds11 Figure A.1 Fitting arrangements18 Figure A.2 Interface for tapping tees and branch saddle tooling19 Figure C.1 Out-of-square dimension boundaries25 Figure E.1 Typical pressure loss test rig28 Figure F.1 Layout of test rig for tapping tee pressure drop test30 Figure J.1 Crush test arrangements33 Figure K.1 Peel test assembly35 Figure K.2 Loading stirrup36 Figure K.3 Test piece geometry36 Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 13:38:23 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 7336:1990 ii © BSI 12-1999 Page Figure K.4 Typical ductile fractures37 Figure K.5 Typical brittle fracture37 Figure Q.1 Typical impact test assembly42 Figure R.1 Schematic diagram of an output cable45 Table 1 Classification of fittings2 Table 2 Socket and coupler dimensions5 Table 3 Overall length of reducers6 Table 4 Dimensions of spigot connections7 Table 5 Pressure drop through saddle connections9 Table 6 Dimension from stub flange face to crown of the main9 Table 7 Fusion times for 40 V systems10 Table 8 Fusion times for 80 V systems10 Table 9 Minimum test pressures for short-term hydrostatic pressure resistance test13 Table 10 Minimum test pressures for long-term hydrostatic pressure resistance test13 Table 11 Test conditions for hydrostatic pressure resistance at 80 °C14 Table 12 End load conditions at 80 °C for jointed sockets or couplers14 Table 13 End load conditions at 80 °C for flanged assemblies14 Table 14 Minimum force for resistance to pull-out or pull-off15 Table 15 Out-of-square limits for spigot or pupped fitting ends15 Table A.1 Test piece preparation and assembly conditions21 Table A.2 Test piece assembly and fusion condition patterns22 Table B.1 Conditioning period23 Table E.1 Correction factors26 Table G.1 Resistance bridge performance characteristics30 Table K.1 Spacing of stirrup hole from the joint fusion zone34 Table N.1 Maximum force correction factors39 Table T.1 Recommended approval test scheme48 Table T.2 Recommended process control schedule49 Table T.3 Sample size code letter49 Table T.4 Double sampling plans50 Table T.5 Sub-batch sampling plans50 Publications referred toInside back cover Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 13:38:23 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 7336:1990 © BSI 12-1999iii Foreword This British Standard has been prepared under the direction of the Plastics Standards Policy Committee. It introduces a specification for fittings made substantially of polyethylene (PE) but incorporating integral heating element(s) to enable fusion jointing with pipes made with compatible grades of polyethylene and intended for use in the conveyance and distribution of natural and manufactured gaseous fuels. The nominal sizes of the fittings covered by this British Standard are 16 mm to 500 mm where these sizes indicate compatibility of fit with PE pipes of the corresponding size (and nominal outside diameter) in accordance with BS 7281. The fittings are intended for use under the same range of operating conditions. The requirements for the electrical components and systems are based upon the design philosophy that the fusion time shall be dependent upon the type and size of the fitting and independent of the grade of PE from which the pipe or fitting is made. This specification is based chiefly upon experience with use of such fittings to convey natural gas as available in the UK. Fittings complying with this specification are considered to be suitable for the conveyance of landfill gas and liquefied petroleum gas provided that the gas composition and the operating conditions are such that the fuel remains at all times in the gaseous state. If other constituents are present and/or condensation of the fuel may affect the performance of the fitting, the maximum allowable working pressure should be carefully evaluated with reference to clause 4 and the note to that clause. Any additional potentially harmful effects to personnel if exposed to the pipework contents, particularly in the case of landfill gases, should be taken into account. The requirements of this British Standard for protection from weathering of the fitting are intended to ensure that the fitting will be satisfactory after storage and handling in accordance with recommended practices prior to installation; it is assumed that in service the fitting will be buried or otherwise protected from weathering. Attention is drawn to CP 312-1, which gives general guidance on storage, handling and installation of plastics pipework, and to CP 312-3, which includes such guidance specific to polyethylene pipework for pressure applications. Attention is also drawn to codes of practice IGE/TD/3 1 and IGE/TD/4 2, published by the Institution of Gas Engineers1), which contain detailed guidance on the use of polyethylene piping systems in the gas industry. In the preparation of this British Standard, attention has been given to the work of Technical Committee 138 of the International Organization for Standardization (ISO), but the requirements of the available draft standard were not considered to be sufficiently stringent for UK application. Attention has also been given to the work aimed at international standardization of methods of extrapolation of data for assessing long-term performance; in the absence as yet of a public ISO document for cross reference, those aspects of the method relevant to this standard have been summarized or reproduced in Appendix A of BS 7281:1990. Attention is drawn to the provisions of the Health and Safety at Work etc. Act, 1974 and the need to take appropriate precautions to ensure the safety of personnel when carrying out the methods of test required by this standard. Product certification. Users of this British Standard are advised to consider the desirability of third party certification of product conformity with this British Standard based on testing and continuing surveillance, which may be coupled with assessment of a suppliers quality systems against the appropriate Part of BS 5750. 1) Available from the Institution of Gas Engineers, 17 Grosvenor Crescent, London SW1X 7ES. Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 13:38:23 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 7336:1990 iv © BSI 12-1999 Enquiries as to the availability of third party certification schemes will be forwarded by BSI to the Association of Certification Bodies. If a third party certification scheme does not already exist, users should consider approaching an appropriate body from the list of Association members. 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 50, 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. Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 13:38:23 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 7336:1990 © BSI 12-19991 1 Scope This British Standard specifies requirements for fusion fittings made substantially of polyethylene (PE) and incorporating integral heating element(s), where the shape and composition of the fitting is suitable for jointing with PE pipe complying with BS 7281 up to and including nominal outside diameter 500 mm and for conveying the following natural and manufactured fuels in the gaseous state (see note 1): a) natural gas (see BS 1179); b) landfill gas (see 2.5); c) liquefied petroleum gas (LPG) (including butane and propane; see BS 1179). Such fittings are intended for use at operating temperatures between 20 °C and + 40 °C and at pressures up to and including 8 bar2), depending upon the material class, the pipe pressure classification and the application (see clause 4 of this standard and clause 4 of BS 7281:1990, including the note). This British Standard is applicable to fittings intended for applications in which the fitting is buried or otherwise protected from weathering. It gives requirements for materials, design characteristics, dimensions, marking, assembly conditions, electrical connections, power requirements, fusion cycle controls, physical properties and hydraulic performance for individual or assembled fittings, as applicable. Methods of test piece preparation and assembly and/or testing are given in Appendix A to Appendix R. Guidance on quality control testing and recommendations for sampling and testing are given in Appendix S and Appendix T respectively. NOTE 1Other gases may have a deleterious effect on the fitting and further testing and evaluation may be necessary. NOTE 2The titles of BSI and ISO standards publications referred to in this standard are listed on the inside back cover. References to publications other than BSI and ISO are identified in the text by numbers in square brackets and are listed in Appendix U. 2 Definitions For the purposes of this British Standard, the definitions given in BS 1179 and BS 1755-1 apply, together with the following. 2.1 branch saddle a lateral fitting which uses ancillary cutters for drilling the hole in the main 2.2 elbow a curved cylinder enabling a change of direction with a maximum centreline radius of one times nominal bore 2.3 flange adaptor a spigot fitting used with a seal/gasket and backing ring(s) for making a mechanical joint in a PE piping system 2.4 inner cold zone for a socket, the distance between the inner end of the fusion coil and the pipe penetration stop of a socket fitting 2.5 landfill gas3) gas, consisting essentially of a mixture of methane and carbon dioxide, extracted during and/or following landfill operations 2.6 masterbatch3) a well-dispersed mixture of a polymer and high percentages of one or more component(s) (colorants and/or other additives) in known proportions for use in blending in appropriate amounts with the basic polymer in the preparation of a compound 2.7 spigot fitting a fitting terminating with a cylindrical end stub, the dimensions of which comply with those of the corresponding pipe 2.8 standard dimension ratio (SDR)4) for a pipe or equivalent hollow right cylinder of circular cross section, the ratio of the specified minimum outside diameter to the specified minimum wall thickness 2.9 tapping tee a lateral fitting that contains an inte