1、BRITISH STANDARD BS6956-5: 1992 Incorporating Amendment No. 1 Jointing materials and compounds Part 5: Specification for jointing compounds for use with water, low pressure saturated steam,1st family gases (excluding coal gas) and2nd family gasesBS6956-5:1992 This British Standard, having been prepa
2、red under the directionof the Piping SystemsComponents Standards Policy Committee, was published underthe authority of the Standards Board and comes into effect on 31January1992 BSI 03-1999 The following BSI references relate to the work on this standard: Committee reference PSE/2 Draft for comment
3、85/75378 DC ISBN 0 580 20256 9 Committees responsible for this British Standard The preparation of this British Standard was entrusted by the Piping Systems Components Standards Policy Committee (PSE/-) to Technical Committee PSE/2, upon which the following bodies were represented: Asbestos Informat
4、ion Centre Ltd. British Adhesives and Sealants Association British Compressed Gases Association British Gas plc British Pump Manufacturers Association British Railways Board Energy Industries Council Engineering Equipment and Materials Users Association Institution of Gas Engineers Institution of Wa
5、ter and Environmental Management Liquefied Petroleum Gas Industry Technical Association (UK) Water Services Association of England and Wales Amendments issued since publication Amd. No. Date Comments 8090 April 1994 Indicated by a sideline in the marginBS6956-5:1992 BSI 03-1999 i Contents Page Commi
6、ttees responsible Inside front cover Foreword ii 1 Scope 1 2 Definitions 1 3 Sampling 1 4 Physical properties 1 5 Testing 1 6 Non-corrosive properties 2 7 Flash point 2 8 Storage properties 2 9 Marking 2 Appendix A Initial pressure test, drying test, temperature cycling test, hydrocarbon test and ho
7、t water test 3 Appendix B Corrosion test 4 Publication(s) referred to Inside back coverBS6956-5:1992 ii BSI 03-1999 Foreword This Part ofBS6956has been prepared under the direction of the Piping Systems Components Standards Policy Committee. It was previously published as section five ofBS5292:1980
8、which has been deleted by amendment. The requirements have been brought into alignment with modern practice and the method of presentation has been changed to align with companion standards. The other Parts ofBS6956specify the following materials and compounds. Part 1: Specification for corrugated m
9、etal joint rings; Part 2 1) : Specification for vulcanized fibre sheets; Part 3 1) : Specification for flexible vulcanized fibre sheets; Part 4 1) : Specification for rubber reinforced jointing; Part 6 1) : Specification for jointing compound for3rd family gases; Part 7 1) : Specification for anaero
10、bic jointing compounds for use with1st,2nd and3rd family gases. WARNING. This British Standard calls for the use of substances and/or procedures that may be injurious to health if adequate precautions are not taken. It refers only to the technical suitability and does not absolve the user from legal
11、 obligations relating to health and safety at any stage 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 lega
12、l obligations. Summary of pages This document comprises a front cover, an inside front cover, pagesi andii, pages1to4, 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
13、 theinside front cover. 1) In preparation.BS6956-5:1992 BSI 03-1999 1 1 Scope This Part ofBS6956 specifies requirements for the physical and sealing properties of jointing compounds for use with water, low pressure saturated steam,1st family gases (excluding coal gas) and2nd family gases. The jointi
14、ng compounds are for use with screwed joints on pipework up to50mm nominal bore with threads up toR2as specified in BS21and for use with the following: a) cold water up to a working pressure of7bar 2) (gauge); b) hot water up to a working pressure of7bar (gauge) and a working temperature of up to100
15、C; c) 1st (excluding coal based) and2nd family gases up to a working pressure of7bar (gauge) and a working temperature of up to150 C; NOTE 1These are typically referred to as Towns Gas and Natural Gas respectively. d) low pressure saturated steam up to a working pressure of7bar (gauge) NOTE 2For cla
16、ssification of1st and2nd family gases seeBS4947. NOTE 3The titles of publications referred to in this standard are listed on the inside back cover. NOTE 4For applications outside these limitations the manufacturer should be consulted. 2 Definitions For the purposes of this Part ofBS6956 the followin
17、g definitions apply. 2.1 jointing compound a manufactured substance which is used for the purpose of sealing screwed metallic joints from the ingress or egress of fluids or gases 2.2 batch any quantity of jointing compound manufactured at one time 3 Sampling A sample sufficient to permit one complet
18、e series of tests to be carried out at one time shall be selected at random from a batch of jointing compound. 4 Physical properties 4.1 General The jointing compound shall be free from lumps and shall have wetting properties necessary for adhesion to metallic surfaces. The solids used in its manufa
19、cture shall be thoroughly ground and the jointing compound shall be in such a condition that stirring will produce a smooth uniform substance. 4.2 Jointing compounds in contact with potable water When used under the conditions for which they are designated, non-metallic products in contact with or l
20、ikely to come into contact with potable water shall comply withBS6920-1. NOTE 1Non-metallic products for installation and use in the United Kingdom which are verified and listed under the UK Water Fittings Byelaws Scheme are deemed to satisfy the requirements of this subclause. Details of the Scheme
21、 are obtainable from Water Research centre (WRc) plc,660Ajax Avenue, Slough SL14BG. Non-metallic products approved by the Department of the Environment Committee on Chemicals and Materials of Construction for use in Public Water Supply and Swimming Pools are considered free from adverse health effec
22、ts for the purposes of compliance with this subclause. NOTE 2A list of approved chemicals and materials and details of the approvals scheme is available from the Secretary of the Committee at the Department of the Environment, Water Division, Romney House,43Marsham Street, London SW1P3PY. 5 Testing
23、5.1 General When tested in accordance with the methods described in Appendix A and Appendix B, the jointing compound shall not disintegrate or flow out of the joint made, shall not permit any leakage during testing and shall permit dismantling of the joints. On completion of the tests no damage incl
24、uding corrosion of the metal parts shall be evident. 5.2 Tests The following tests shall be carried out as described in Appendix A and Appendix B: a) initial pressure test (see A.3.1); b) drying test (see A.3.2); c) resistance to temperature cycling test (seeA.3.3); d) resistance to hydrocarbon test
25、 (see A.3.4); e) resistance to hot water test (see A.3.5); f) corrosion test (see Appendix B). 2) 1 bar = 10 5N/m 2=100kPa.BS6956-5:1992 2 BSI 03-1999 5.3 Retest If the joint fails in more than one of the tests specified in 5.2, no retests shall be permitted. If the joint in any one test assembly fa
26、ils to comply with the requirements of any test, two further test assemblies shall be prepared using jointing compound from the same batch, and each shall comply with the requirements of that test. If the joint of either or both of the retest assemblies fails, it shall be deemed that the whole batch
27、 has failed. 5.4 Test conditions The conditions for all tests shall be a pressure of14bar (gauge). NOTEThe test pressure is usually 1 times the working pressure but14bar has been chosen to align with the water industrys practice of testing underground piping at twice the working pressure. 6 Non-corr
28、osive properties The jointing compound shall not cause corrosion of copper, brass, aluminium or low-carbon steel surfaces when tested in accordance with the method described in Appendix B. 7 Flash point The flash point temperature, when determined by the Abel apparatus in accordance with BS 2000-170
29、, shall be not less than13C. 8 Storage properties The jointing compound when stored under conditions specified by the manufacturer and in its original unopened container shall retain the original properties for a minimum period of 2 years. 9 Marking Packages of jointing compound shall be plainly, cl
30、early and indelibly marked with the following information. a) The manufacturers name, and trademark. b) The number of this British Standard, i.eBS6956-5 3) . c) The intended use of the jointing compound,e.g.for use with pipework carrying cold water, hot water, low pressure saturated steam,1st and2nd
31、 family gases for screwed joints up to50mm,7bar pressure and200C temperature. d) Either whether suitable for use with potable water or whether listed by the UK Water Fittings Byelaws Scheme (see 4.2). e) A unique identification mark providing traceability,e.g.a manufacturing batch number. f) Method
32、of application. 3) MarkingBS6956-5 on or in relation to a product represents a manufacturers declaration of conformity,i.e.a claim by or on behalf of the manufacturer that the product meets the requirements of the standard. The accuracy of the claim is therefore solely the responsibility of the pers
33、on making the claim. Such a declaration is not to be confused with third party certification of conformity, which may also be desirable.BS6956-5:1992 BSI 03-1999 3 Appendix A Initial pressure test, drying test, temperature cycling test, hydrocarbon test and hot water test A.1 Apparatus A.1.1 Heavy t
34、ube, six250mm lengths of25mm tube complying withBS1387 and threadedR1in accordance withBS21. A.1.2 Six steel sockets threaded R p 1 in accordance withBS21. A.1.3 Six steel plugs, externally threaded R c 1complying withBS21:1985. A.1.4 Air or nitrogen supply of140.5bar (gauge) pressure. A.1.5 Oven, c
35、apable of holding the assemblies with a heating facility to raise the temperature to2005C. A.1.6 Water bath, of sufficient capacity to hold the assemblies. A.1.7 Four steel sealing plugs, externally threaded R c 1 complying withBS21:1985. A.1.8 Six steel reducing sockets, threaded R p 1 complying wi
36、thBS21:1985. A.2 Preparation of test assemblies Prepare six test assemblies, each assembly consisting of a250mm length of25mm heavy tube(A.1.1), a steel socket (A.1.2), a steel plug(A.1.3) and a steel reducing socket (A.1.8). Clean the threads of all swarf, paint, oil or other contaminants before ap
37、plying the compound. Evenly coat the whole of the external threads on the tube with the jointing compound, completely filling the threads. Do not apply jointing compound to the socket. Screw the socket to the pipe until hand tight and using a suitable gripping tool tighten with a torque of100Nm. Rem
38、ove any excess jointing compound from the outside of the joint. In a similar manner screw the plug into the socket and screw the reducing socket on to the other end of the tube, taking care not to transmit the torque to joints already made. A.3 Tests A.3.1 Initial pressure test Connect each test ass
39、embly in turn to an air pressure or nitrogen supply at 14 bar (gauge) pressure (A.1.4) and slowly pressurize it. Immerse each assembly in a water bath (A.1.6) at20C5C for a minimum of5min and inspect it for any leakage by observing any bubbles that appear. Ignore any bubbles that appear during the f
40、irst15s of immersion. Report whether theR1 joints on the assemblies hold pressure or leak. A.3.2 Drying test De-pressurize the test assemblies used in A.3.1, stand vertically and allow to dry for168h at a temperature of205C. Repeat the procedure described in A.3.1. A.3.3 Resistance to temperature cy
41、cling test Select two test assemblies that were leak free inA.3.1 andA.3.2. Heat these in the oven (A.1.5) to a test temperature of2005C, hold at this temperature for1h and cool to room temperature. Repeat for a total of six cycles, each cycle lasting approximately1 h. Repeat the procedure described
42、 in A.3.1 for both assemblies. A.3.4 Resistance to hydrocarbon test Fill two new test assemblies that were leak free inA.3.1 andA.3.2 with a mixture of70%by volume2,2,4-trimethyl pentane and30%by volume of toluene, and seal the reducing sockets(A.1.8) with the sealing plugs (A.1.7). Allow them to st
43、and vertically for168h at ambient temperature. At the end of the test period carefully remove the plugs and drain the test assembly. Repeat the procedure described in A.3.1 for both assemblies. A.3.5 Resistance to hot water test Fill two new test assemblies that were leak free inA.3.1 andA.3.2 with
44、water, and seal the reducing sockets (A.1.8) with the sealing plugs (A.1.7). Place the assemblies in an oven (A.1.5) at100C5C for6h. At the end of this period remove the assemblies, allow them to cool to room temperature, remove the plugs and drain off the water. Repeat the procedure described in A.
45、3.1 for both assemblies. A.3.6 Cleaning and inspection After all tests have been completed, dismantle the joints, clean and inspect the fittings and report any damage or corrosion observed.BS6956-5:1992 4 BSI 03-1999 A.4 Results Report whether the test assemblies held pressure or leaked during the t
46、ests carried out as described inA.3.1 toA.3.5. Also report whether any damage or corrosion to the fittings was detected during the inspection of A.3.6 Appendix B Corrosion test B.1 Apparatus B.1.1 Tall form glass beaker, of100mL capacity. B.1.2 Metal strips, of commercial copper, brass, aluminium an
47、d low carbon steel, not less than0.5mm thick, cut into pieces75mm long and13mm wide. B.1.3 Spatula. B.1.4 Oven, capable of maintaining a temperature of651C. B.1.5 Clean pair of forceps. B.2 Materials B.2.1 Emery paper, No.150grade. B.2.2 1,1,1-trichloroethane, as specified inBS4487. B.2.3 Industrial
48、 methylated spirit, as specified inBS3591. B.2.4 Cotton wool. B.3 Preparation of metal strips Mechanically polish the two faces of each strip(B.1.2) to obtain a uniform finish free from defects. Clean and polish each strip with the emery paper(B.2.1) and then with successive pads of cotton wool unti
49、l a fresh pad remains unsoiled after use. Wash each strip with1,1,1-trichloroethane (B.2.2) and allow to dry. Use clean forceps (B.1.5) for all further handling of the strips. B.4 Procedure Fill the beaker (B.1.1) with a sample of the jointing compound to within6mm of the top, level and smooth the surface with the spatula (B.1.3). Coat each freshly prepared strip with a thin film of the sample for a distance of48mm from one end and insert that end vertically to a depth of50mm into the sample of jointing compound contained in the be
