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1、BRITISH STANDARD BS 7531:1992 Specification for Compressed non-asbestos fibre jointing Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 11:34:44 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 7531:1992 This British Standard, having been prepared under the directio
2、n 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 03-2000 The following BSI references relate to the work on this standard: Committee reference PSE/2 Draft for comment 91/73377 DC ISBN
3、0 580 20248 8 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 Information Centre Ltd. B
4、ritish 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 Health and Safety Executive Institution of Gas Engineers Instit
5、ution of Water and Environmental Management Liquefied Petroleum Gas Industry Technical Association (UK) Water Services Association of England and Wales Amendments issued since publication Amd. No.DateComments Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 11:34
6、:44 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 7531:1992 BSI 03-2000i Contents Page Committees responsibleInside front cover Forewordii 1Scope1 2Definitions1 3Material and grades1 4Finish1 5Thickness1 6Tests2 7Retest2 8Marking2 9Test certificate3 Appendix A Information to be supplied by purchaser
7、4 Appendix B Method of carrying out residual stress test4 Appendix C Method of carrying out resistance to oil and water absorption tests5 Appendix D Method of carrying out compressibility test7 Appendix E Method of carrying out gas permeability test7 Appendix F Method of test to determine maximum st
8、ress value8 Appendix G Method of calibration of residual stress testing apparatus9 Figure 1 General assembly of residual stress testing apparatus10 Figure 2 Details of residual stress testing apparatus11 Figure 3 Details of dynamometer for calibration of residual stress testing apparatus12 Figure 4
9、Typical calibration curve for residual stress testing apparatus13 Figure 5 Typical layout of test apparatus for sealability14 Figure 6 Arrangement for calibration of dynamometer at increased temperatures15 Figure 7 Dynamometer15 Table 1 Tolerance for thickness of sheet2 Publication(s) referred toIns
10、ide back cover Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 11:34:44 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 7531:1992 ii BSI 03-2000 Foreword This British Standard has been prepared under the direction of the Piping Systems Components Standards Policy
11、Committee. This standard is one of a series of standards specifying the following materials and compounds. BS 1832, Specification for compressed asbestos fibre jointing. BS 6956, Jointing materials and compounds. Part 1: Specification for corrugated metal joint rings; Part 2: Specification for vulca
12、nized fibre sheets1); Part 3: Specification for flexible vulcanized fibre sheets1); Part 4: Specification for rubber reinforced jointing1); Part 5: Specification for jointing compounds for use with water, low pressure saturated steam, 1st family gases (excluding coal gas) and 2nd family gases; Part
13、6: Specification for jointing compound for 3rd family gases; Part 7: Specification for anaerobic jointing compounds for use with 1st, 2nd and 3rd family gases1). WARNING. This British Standard calls for the use of substances and/or procedures that may be injurious to health if adequate precautions a
14、re not taken. It refers only to the technical suitability and does not absolve the user 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 c
15、orrect application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Attention is drawn particularly to the Health and Safety at Work etc. Act 1974. Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, pages 1 to
16、16, 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. 1) In preparation. Licensed Copy: London South Bank University, London South Bank Universi
17、ty, Fri Dec 08 11:34:44 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 7531:1992 BSI 03-20001 1 Scope This British Standard specifies the requirements for the manufacture, quality and finish, thickness and testing of elastomer bonded compressed fibre jointing material that does not contain asbestos.
18、NOTE 1Appendix A lists the information which is to be supplied by the purchaser. NOTE 2The titles of the publications referred to in this standard are given on the inside back cover. 2 Definitions For the purposes of this British Standard the following definitions apply. 2.1 jointing a manufactured
19、solid run single-ply material supplied in sheets, from which required shapes can be cut and used for the purpose of sealing mating faces of components from the ingress or egress of fluids 2.2 inert fluid a gas or liquid (other than aqueous) which under no circumstances will cause any chemical reacti
20、on with any part of the jointing or tend to cause any disintegration 2.3 manufacturing run that amount of jointing all of one grade in units of a maximum of 5 t 3 Material and grades 3.1 Material The material shall consist of fibres and inorganic fillers bonded with a suitable elastomer or blend of
21、elastomers, and shall be manufactured in the form of sheets. The fibres shall be uniformly dispersed throughout the jointing. NOTEExamples of fibres that may be used (singly or in combination) are aramid, carbon and glass. Asbestos fibres shall not be used. 3.2 Grades This standard provides for two
22、grades as follows. a) Grade X shall be suitable for water, steam and gases at temperatures up to 250 C and for oil, solvents and inert liquids at temperatures up to 440 C. b) Grade Y shall be suitable for water, steam and gases at temperatures up to 200 C and for oil, solvents and inert liquids at t
23、emperatures up to 350 C. NOTEThe purchaser should state in his enquiry and/or order which grade is required. 3.3 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 comp
24、ly with the requirements of BS 6920-1:1988. 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 clause. Details of the Scheme are obtainable from WRc plc, 66
25、0 Ajax Avenue, Slough SL1 4BG. 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 effects for the purposes of compliance with this clause. N
26、OTE 2A list of approved chemicals and materials and details of the approvals scheme are available from the Secretary of the Committee at the Department of the Environment, Water Division, Romney House, 43 Marsham Street, London SW1P 3PY. NOTE 3The purchaser should state in his enquiry and/or order w
27、hether when used under the conditions for which they are designated, non-metallic products come or are likely to come into contact with potable water (see Appendix A). 4 Finish The sheets of either grade of jointing shall be of uniform texture, smooth on both sides and free from irregularities such
28、as blisters, tears and lumps. NOTEWhen required by the purchaser, one or both surfaces may be treated with graphite or other acceptable release agent (see Appendix A). 5 Thickness 5.1 Nominal thickness The nominal thickness of either grade of jointing shall be one of the following: a) 0.5 mm; b) 0.7
29、5 mm; c) 1.0 mm; d) 1.5 mm; e) 2.0 mm. NOTEThe purchaser should state in his enquiry and/or order the thickness required. 5.2 Thickness tolerance The maximum variation of any sheet from the nominal thicknesses, and the maximum permissible variation in thickness between any points not more than 250 m
30、m apart on a sheet shall be in accordance with Table 1. Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 11:34:44 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 7531:1992 2 BSI 03-2000 Table 1 Tolerance for thickness of sheet 5.3 Thickness measurement The thicknes
31、s shall be measured with either: a) a ratchet micrometer complying with BS 870 and having an anvil of 6 mm to 16 mm in diameter. The reading shall be taken after three clicks of the ratchet; or b) a dial type micrometer complying with BS 907, with a flat pressure foot of not less than 6 mm diameter
32、and a flat anvil of diameter not less than that of the pressure foot. 6 Tests 6.1 Samples The manufacturer shall select from each manufacturing run of jointing, a sample or samples including those treated with graphite where appropriate (see clause 4 and Appendix A) sufficient to provide the test pi
33、eces for one complete series of tests as specified in this clause. The manufacturer shall carry out tests in accordance with 6.2 to 6.5 for each manufacturing run of jointing. 6.2 Residual stress The residual stress when determined in accordance with Appendix B shall be not less than 25 MPa for grad
34、e X or 22 MPa for grade Y. 6.3 Resistance to oil and water absorption 6.3.1 Oil When determined in accordance with Appendix C the oil absorption shall not be greater than the following: a) 20 % as measured by increase in the original thickness for jointing of 0.5 mm and 0.75 mm thickness; b) 10 % as
35、 measured by increase in the original thickness for jointing over 0.75 mm thickness. 6.3.2 Water When determined in accordance with Appendix C the water absorption shall not be greater than 15 % as measured by increase in the original thickness of the jointing. 6.4 Compressibility When determined in
36、 accordance with Appendix D, jointing of 0.75 mm nominal thickness and above shall show a depth of the impression, expressed as a percentage of the original thickness under preload, of not less than 6 %. NOTEValues for thickness of 0.5 mm have been omitted owing to the practical difficulty of making
37、 satisfactory measurements. 6.5 Gas permeability When determined in accordance with Appendix E the leakage shall not exceed 1 mL/min. 7 Retest If any sample fails to comply with the requirements related to any appropriate test, two further samples shall be selected from the same manufacturing run fo
38、r retesting and each shall comply with the requirements of the test(s). If either of the retest samples fails the test the whole manufacturing run of material shall be deemed not to comply with this British Standard. 8 Marking 8.1 Every sheet of jointing shall be indelibly marked with the number of
39、this British Standard and the grade of the material, e.g. BS 75312) Grade X. 8.2 If the jointing is marked with the manufacturers identification mark this shall be indelibly marked on every 300 mm 300 mm of the jointing. NOTEIf the purchaser does not require the manufacturers identification mark thi
40、s should be stated in the enquiry or order (see Appendix A). 8.3 When the individual marking of small items is impracticable, the markings specified in 8.1 shall be shown clearly on the package. Nominal thickness of sheet Maximum permissible variation from nominal thickness Maximum permissible varia
41、tion in thickness between points not more than 250 mm apart mm 0.5 0.75 and 1.0 1.5 and 2.0 mm 0.05 0.10 0.15 mm 0.05 0.10 0.10 2) Marking BS 7531 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 me
42、ets the requirements of the standard. The accuracy of the claim is therefore solely the responsibility of the person making the claim. Such a declaration is not to be confused with third party certification of conformity, which may also be desirable. Licensed Copy: London South Bank University, Lond
43、on South Bank University, Fri Dec 08 11:34:44 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 7531:1992 BSI 03-20003 9 Test certificate If the purchaser requires a test certificate for each consignment it shall be worded as follows. “We hereby certify that the . . . . . . . jointing supplied complies
44、in all respects with the requirements of BS 7531, Specification for compressed non-asbestos fibre jointing. Grade . . . . . . . The identification marks on the jointing are . . . . . . .” NOTEA test certificate is not normally provided. The purchaser should state in his enquiry and/or order whether
45、a test certificate is required (see Appendix A). Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 11:34:44 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 7531:1992 4 BSI 03-2000 Appendix A Information to be supplied by purchaser It is the responsibility of the pur
46、chaser to ensure compliance with any appropriate application standard or code of practice. The purchaser should specify the following information in his enquiry and order: a) the number of this British Standard, i.e. BS 7531:1991 (see 8.1); b) the grade of jointing required (see 3.2); c) the thickne
47、ss required (see 5.1); d) the dimensions of sheets required; e) the quantity of sheets required; f) if the jointing will or is likely to come into contact with potable water (see 3.3); g) if the manufacturers identification mark is not required to be indelibly marked on every 300 mm 300 mm of the jo
48、inting (see 8.2); h) if a test certificate is required (see clause 9); i) if one or both surfaces should be treated with a suitable release agent, e.g. graphite (see clause 4). Appendix B Method of carrying out residual stress test B.1 Principle The measurement of residual stress after 16 h at 300 C
49、 from an initial stress of 40 MPa. B.2 Apparatus B.2.1 The general arrangement and details of the apparatus are given in Figure 1 to Figure 3. B.2.2 The central bolt and bottom flange support are made in one piece. Threads on the bolt are in accordance with Figure 2 and of ISO metric form to BS 3643-1. The bottom flange is fitted with a thermocouple junction pressed and fixed firmly against the end of the thermocouple hole. B.2.3 The central bolt incorporating the bottom flange support is made of steel to BS 1506 type 671, heat
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