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1、BRITISH STANDARD BS 6956-5: 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) and 2nd family gases Licensed Copy: sheffieldun sheffieldun, na, Tue De
2、c 05 05:51:42 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 6956-5:1992 This British Standard, having been prepared under the direction of the Piping Systems Components Standards Policy Committee, was published under the authority of the Standards Board and comes into effect on 31 January 1992 BSI 0
3、3-1999 The following BSI references relate to the work on this standard: Committee reference PSE/2 Draft for comment 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 Polic
4、y Committee (PSE/-) to Technical Committee PSE/2, upon which the following bodies were represented: Asbestos Information Centre Ltd. British Adhesives and Sealants Association British Compressed Gases Association British Gas plc British Pump Manufacturers Association British Railways Board Energy In
5、dustries Council Engineering Equipment and Materials Users Association Institution of Gas Engineers Institution of Water and Environmental Management Liquefied Petroleum Gas Industry Technical Association (UK) Water Services Association of England and Wales Amendments issued since publication Amd. N
6、o.DateComments 8090April 1994 Indicated by a sideline in the margin Licensed Copy: sheffieldun sheffieldun, na, Tue Dec 05 05:51:42 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 6956-5:1992 BSI 03-1999i Contents Page Committees responsibleInside front cover Forewordii 1Scope1 2Definitions1 3Sampling
7、1 4Physical properties1 5Testing1 6Non-corrosive properties2 7Flash point2 8Storage properties2 9Marking2 Appendix A Initial pressure test, drying test, temperature cycling test, hydrocarbon test and hot water test3 Appendix B Corrosion test4 Publication(s) referred toInside back cover Licensed Copy
8、: sheffieldun sheffieldun, na, Tue Dec 05 05:51:42 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 6956-5:1992 ii BSI 03-1999 Foreword This Part of BS 6956 has been prepared under the direction of the Piping Systems Components Standards Policy Committee. It was previously published as section five of
9、BS 5292:1980 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 of BS 6956 specify the following materials and compounds. Part 1: Specification
10、for corrugated metal joint rings; Part 21): Specification for vulcanized fibre sheets; Part 31): Specification for flexible vulcanized fibre sheets; Part 41): Specification for rubber reinforced jointing; Part 61): Specification for jointing compound for 3rd family gases; Part 71): Specification for
11、 anaerobic jointing compounds for use with 1st, 2nd and 3rd 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
12、from legal 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
13、 from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, pages 1 to 4, 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 ame
14、ndment table on the inside front cover. 1) In preparation. Licensed Copy: sheffieldun sheffieldun, na, Tue Dec 05 05:51:42 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 6956-5:1992 BSI 03-19991 1 Scope This Part of BS 6956 specifies requirements for the physical and sealing properties of jointing co
15、mpounds for use with water, low pressure saturated steam, 1st family gases (excluding coal gas) and 2nd family gases. The jointing compounds are for use with screwed joints on pipework up to 50 mm nominal bore with threads up to R2 as specified in BS 21 and for use with the following: a) cold water
16、up to a working pressure of 7 bar2)(gauge); b) hot water up to a working pressure of 7 bar (gauge) and a working temperature of up to 100 C; c) 1st (excluding coal based) and 2nd family gases up to a working pressure of 7 bar (gauge) and a working temperature of up to 150 C; NOTE 1These are typicall
17、y referred to as Towns Gas and Natural Gas respectively. d) low pressure saturated steam up to a working pressure of 7 bar (gauge) NOTE 2For classification of 1st and 2nd family gases see BS 4947. NOTE 3The titles of publications referred to in this standard are listed on the inside back cover. NOTE
18、 4For applications outside these limitations the manufacturer should be consulted. 2 Definitions For the purposes of this Part of BS 6956 the following definitions apply. 2.1 jointing compound a manufactured substance which is used for the purpose of sealing screwed metallic joints from the ingress
19、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 complete 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 j
20、ointing compound shall be free from lumps and shall have wetting properties necessary for adhesion to metallic surfaces. The solids used in its manufacture shall be thoroughly ground and the jointing compound shall be in such a condition that stirring will produce a smooth uniform substance. 4.2 Joi
21、nting compounds in contact with potable water When used under the conditions for which they are designated, non-metallic products in contact with or likely to come into contact with potable water shall comply with BS 6920-1. NOTE 1Non-metallic products for installation and use in the United Kingdom
22、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 are obtainable from Water Research centre (WRc) plc, 660 Ajax Avenue, Slough SL1 4BG. Non-metallic products approved by the Department of the Envir
23、onment Committee on Chemicals and Materials of Construction for use in Public Water Supply and Swimming Pools are considered free from adverse health effects for the purposes of compliance with this subclause. NOTE 2A list of approved chemicals and materials and details of the approvals scheme is av
24、ailable from the Secretary of the Committee at the Department of the Environment, Water Division, Romney House, 43 Marsham Street, London SW 1P 3PY. 5 Testing 5.1 General When tested in accordance with the methods described in Appendix A and Appendix B, the jointing compound shall not disintegrate o
25、r 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 including corrosion of the metal parts shall be evident. 5.2 Tests The following tests shall be carried out as described in Appendix A and Append
26、ix B: a) initial pressure test (see A.3.1); b) drying test (see A.3.2); c) resistance to temperature cycling test (see A.3.3); d) resistance to hydrocarbon test (see A.3.4); e) resistance to hot water test (see A.3.5); f) corrosion test (see Appendix B). 2) 1 bar = 105 N/m2 = 100 kPa. Licensed Copy:
27、 sheffieldun sheffieldun, na, Tue Dec 05 05:51:42 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 6956-5:1992 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 fails to comply with the requir
28、ements 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 has failed. 5.4 Test conditi
29、ons The conditions for all tests shall be a pressure of 14 bar (gauge). NOTEThe test pressure is usually 1 times the working pressure but 14 bar has been chosen to align with the water industrys practice of testing underground piping at twice the working pressure. 6 Non-corrosive properties The join
30、ting 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, shall be not less than
31、13 C. 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, clearly and indelibly mar
32、ked with the following information. a) The manufacturers name, and trademark. b) The number of this British Standard, i.e BS 6956-53). c) The intended use of the jointing compound, e.g. for use with pipework carrying cold water, hot water, low pressure saturated steam, 1st and 2nd family gases for s
33、crewed joints up to 50 mm, 7 bar pressure and 200 C 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 of applicat
34、ion. 3) Marking BS 6956-5 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 person maki
35、ng the claim. Such a declaration is not to be confused with third party certification of conformity, which may also be desirable. Licensed Copy: sheffieldun sheffieldun, na, Tue Dec 05 05:51:42 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 6956-5:1992 BSI 03-19993 Appendix A Initial pressure test, d
36、rying test, temperature cycling test, hydrocarbon test and hot water test A.1 Apparatus A.1.1 Heavy tube, six 250 mm lengths of 25 mm tube complying with BS 1387 and threaded R1 in accordance with BS 21. A.1.2 Six steel sockets threaded Rp1 in accordance with BS 21. A.1.3 Six steel plugs, externally
37、 threaded Rc1 complying with BS 21:1985. A.1.4 Air or nitrogen supply of 14 0.5 bar (gauge) pressure. A.1.5 Oven, capable of holding the assemblies with a heating facility to raise the temperature to 200 5 C. A.1.6 Water bath, of sufficient capacity to hold the assemblies. A.1.7 Four steel sealing p
38、lugs, externally threaded Rc1 complying with BS 21:1985. A.1.8 Six steel reducing sockets, threaded Rp1 complying with BS 21:1985. A.2 Preparation of test assemblies Prepare six test assemblies, each assembly consisting of a 250 mm length of 25 mm heavy tube (A.1.1), a steel socket (A.1.2), a steel
39、plug (A.1.3) and a steel reducing socket (A.1.8). Clean the threads of all swarf, paint, oil or other contaminants before applying 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
40、 socket. Screw the socket to the pipe until hand tight and using a suitable gripping tool tighten with a torque of 100 Nm. Remove 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 tu
41、be, taking care not to transmit the torque to joints already made. A.3 Tests A.3.1 Initial pressure test Connect each test assembly 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) at 20 C 5 C for
42、 a minimum of 5 min and inspect it for any leakage by observing any bubbles that appear. Ignore any bubbles that appear during the first 15 s of immersion. Report whether the R1 joints on the assemblies hold pressure or leak. A.3.2 Drying test De-pressurize the test assemblies used in A.3.1, stand v
43、ertically and allow to dry for 168 h at a temperature of 20 5 C. Repeat the procedure described in A.3.1. A.3.3 Resistance to temperature cycling test Select two test assemblies that were leak free in A.3.1 and A.3.2. Heat these in the oven (A.1.5) to a test temperature of 200 5 C, hold at this temp
44、erature for 1 h and cool to room temperature. Repeat for a total of six cycles, each cycle lasting approximately 1 h. Repeat the procedure described in A.3.1 for both assemblies. A.3.4 Resistance to hydrocarbon test Fill two new test assemblies that were leak free in A.3.1 and A.3.2 with a mixture o
45、f 70 % by volume 2,2,4-trimethyl pentane and 30 % by volume of toluene, and seal the reducing sockets (A.1.8) with the sealing plugs (A.1.7). Allow them to stand vertically for 168 h at ambient temperature. At the end of the test period carefully remove the plugs and drain the test assembly. Repeat
46、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 in A.3.1 and A.3.2 with 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) at 100 C 5 C for 6 h.
47、 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.3.1 for both assemblies. A.3.6 Cleaning and inspection After all tests have been completed, dismantle the joints, clean and inspect
48、the fittings and report any damage or corrosion observed. Licensed Copy: sheffieldun sheffieldun, na, Tue Dec 05 05:51:42 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 6956-5:1992 4 BSI 03-1999 A.4 Results Report whether the test assemblies held pressure or leaked during the tests carried out as des
49、cribed in A.3.1 to A.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, of 100 mL capacity. B.1.2 Metal strips, of commercial copper, brass, aluminium and low carbon steel, not less than 0.5 mm thick, cut into pieces 75 mm long and 13 mm wide. B.1.3 Spatula. B.1.4 Oven, capable of maintaining a temperature of 65 1 C. B.1.5 Clean pair of forceps. B.2 Materials B.2.1 Emery paper, No. 150 grade. B.2.2
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