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1、BRITISH STANDARD BS 229:1957 Incorporating Amendment Nos. 1, 2, 3, 4, 5, 6, 7, 8 and 9 Specification for Flameproof enclosure of electrical apparatus UDC 621.316.6:62-213.34:614.839.4 Licensed Copy: sheffieldun sheffieldun, na, Tue Nov 28 13:49:16 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 229:19
2、57 This British Standard, having been approved by the Electrical Industry Standards Committee and endorsed by the Chairman of the Engineering Divisional Council, was published under the authority of the General Council on 30 March 1957 BSI 10-1999 First published November 1926 First revision March 1
3、929 Second revision November 1940 Third revision May 1946 Fourth revision March 1957 The following BSI references relate to the work on this standard: Committee references ELE/31 and ELE/31/2 Draft for comment CV(ELE) 1336 ISBN 0 580 00932 7 Co-operating organizations The Electrical Industry Standar
4、ds Committee, under whose supervision this British Standard was prepared, consists of representatives from the following Government departments and scientific and industrial organizations: The Government departments and scientific and industrial organizations marked with an asterisk in the above lis
5、t, together with the following, were directly represented on the Committee entrusted with the preparation of the standard: AdmiraltyElectrical Contractors Association Air Ministry*(Incorporated) Associated Offices Technical CommitteeElectrical Contractors Association of Scotland Association of Consu
6、lting Engineers Engineering Equipment Users Association* (Incorporated)General Post Office Association of Supervising Electrical EngineersIndependent Cable Makers Association British Electrical and Allied Industries Institution of Electrical Engineers Research Association*Ministry of Labour and Nati
7、onal Service British Electrical and Allied Manufacturers (Factory Department)* Association*Ministry of Power* British Electrical Development AssociationMinistry of Supply British Railways, The British Transport Ministry of Works CommissionNational Physical Laboratory (D.S.I.R.) Cable Makers Associat
8、ion*North of Scotland Hydro Electric Board Central Electricity Authority and Area BoardsOil Companies Materials Committee* Crown Agents for Oversea Governments and Public Transport Association (Incorporated) AdministrationsRadio Industry Council Electric Lamp Manufacturers AssociationSouth of Scotla
9、nd Electricity Board Electric Light Fittings AssociationWar Office Association of Mining Electrical and Institute of Petroleum Mechanical EngineersLloyds Register of Shipping Council of Underground Machinery National Coal Board ManufacturersManufacturers of Chemicals Fire Offices Committee Amendment
10、s issued since publication Amd. No.Date of issueComments 2958January 1958 3002April 1958 3247December 1958 3543October 1959 4908May 1963 6162May 1967 359October 1969 1610July 1974 5224March 1987Indicated by a sideline in the margin Licensed Copy: sheffieldun sheffieldun, na, Tue Nov 28 13:49:16 GMT+
11、00:00 2006, Uncontrolled Copy, (c) BSI BS 229:1957 BSI 10-1999i Contents Page Co-operating organizationsInside front cover Forewordiii Section 1. General1 1Scope1 2Definition of flameproof enclosure1 Section 2. Apparatus to be enclosed1 3Design of apparatus1 Section 3. Grouping of gases and classifi
12、cation of gap dimensions1 4Permissible dimensions1 Section 4. Construction of the enclosure3 5Precautions against internal insulation failure3 6Mechanical strength of the enclosure4 7Joints4 8Operating rods and spindles5 9Shafts and bearings for motors or generators5 10Windows9 11Sub-division of enc
13、losures13 12Breathing and draining devices13 13Air-gap inspection openings for motors and generators13 14Attachment of parts and fittings13 15Shrouding of nuts, bolts, etc.13 16Bolts, screws and studs14 17Provision for the connection of external circuit conductors14 18Terminal and insulating bushes2
14、0 19Terminal boxes20 20Cable sealing and dividing boxes20 21Conduit stopper boxes20 22Plug and socket couplings20 Section 5. Marking20 23Nature and method of marking20 Section 6. Tests and test reports21 24Tests of flameproofness by the testing authority21 25Reports of tests of flameproofness21 26Te
15、sts at the manufacturers works21 Appendix A Procedure for certification of apparatus26 Appendix B Cement for fixing windows, as required by Clause 1026 Appendix C The registered flameproof mark28 Annex Data regarding the basis of the requirements of the specification28 Figure 1 Type of gland suitabl
16、e for ball or roller bearings5 Figure 2 Labyrinth type of gland; suitable for both sleeve bearings and ball and roller bearings6 Figure 3 Typical floating gland7 Figure 4 Typical cemented mountings8 Figure 5 Typical cemented mounting10 Figure 6 Typical cemented mounting11 Figure 7 Typical non-cement
17、ed mounting12 Licensed Copy: sheffieldun sheffieldun, na, Tue Nov 28 13:49:16 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 229:1957 ii BSI 10-1999 Page Figure 8 Typical means of shrouding nuts, bolts, screws, etc., used for securing covers15 Figure 9 Unfilled terminal box with access door and detac
18、hable cable sealing and dividing box for armoured cables16 Figure 10 Unfilled terminal box without access door with detachable cable sealing and dividing box for small cables16 Figure 11 Terminal boxes arranged for wiring in conduit of 1 in. or less in diameter see Sub-clause 17 b)17 Figure 12 Termi
19、nal boxes arranged for wiring in conduit of diameter greater than 1 in. see Sub-clause 17 b)17 Figure 13 Bolted plug and socket coupling18 Figure 14 Restrained plug and coupling18 Figure 15 Bolted flit-plug and adaptor19 Figure 16 Tests of joint surfaces using straightedges23 Figure 17 Examples of t
20、he use of dowel pins to permit direct observation of the fit of covers24 Figure 18 Method of weatherproofing a flameproof enclosure25 Table 1 Grouping and corresponding gap dimensions for flammable gases and vapours2 Table 2 Minimum lengths of engaged thread for screwed conduit used on flameproof en
21、closures5 Table A Data supplied by the British electrical and allied industries research association30 Licensed Copy: sheffieldun sheffieldun, na, Tue Nov 28 13:49:16 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 229:1957 BSI 10-1999iii Foreword This standard makes reference to the following British
22、 Standards: BS 31, Steel conduits and fittings for electrical wiring. BS 239, White pigments for paints. BS 292, Dimensions of ball bearings and parallel-roller bearings. BS 410, Test sieves. BS 889, Flameproof electric lighting fittings (bulkhead and well-glass types). BS 970, Wrought steels for ge
23、neral engineering purposes. BS 1387, Steel tubes and tubulars suitable for screwing to BS 21 pipe threads. BS 1858, Bitumen-base filling compounds for electrical purpose. BS 2474, Recommended names for chemicals used in industry. BS 2558, Tubular box spanners. BS 4568, Steel conduits and fittings wi
24、th metric threads of ISO form for electrical installations. BS 4683, Electrical apparatus for explosive atmosphere Part 2: The construction and testing of flameproof enclosures of electrical apparatus. BS 5501, Electrical apparatus for potentially explosive atmospheres. BS 5501-5, Flameproof enclosu
25、re “d”. This British Standard, prepared under the authority of the Electrical Industry Standards Committee, supersedes the 1946 edition. The foreword of the 1946 edition refers to research carried out by the British Electrical and Allied Industries Research Association in collaboration with the Safe
26、ty in Mines Research Establishment. The research has continued into the characteristics of a greater number of flammable1) gases and vapours and has embraced work on both one inch and half inch joint breadths. At the same time the method of assessment of the statistical maximum safe gap has been rec
27、onsidered, with the result that a more precise method of grouping the various gases and vapours has been evolved. This has resulted in a few changes of grouping. Data on gases and vapours included in any group will be extended when the results of further research are made available. The maximum perm
28、issible gap, specified in Table 1, has a dimension which is less than that of the statistical maximum safe gap referred to above. This is to provide some margin of safety essential in respect of possible contingencies arising in course of practical use; for example, small undetected alteration or de
29、terioration of gaps. The requirements for large rotating machines with sleeve bearings for Group II Combustibles have been amended to make the construction and operation of such apparatus more practicable. To simplify the presentation of the standard, supplementary data regarding the basis of the re
30、quirements specified are given in an Annex which included a revision of Appendix F of the 1946 edition to give guidance in the case of gases for which tests are not yet completed. Although only requirements for flameproof enclosure are given it is recognized that the apparatus may have to operate in
31、 places where, for example, moisture or dust is present. It would be inappropriate to specify, in this standard, the supplementary requirements to cover such protection, but care has been taken in drafting that such requirements are not excluded provided that any additions to the enclosure itself do
32、 not impair its flameproof qualities (see Clause 7, page 4, paragraphs 8 and 9). By way of example an accepted method of weatherproofing a flameproof enclosure is given in Figure 18. 1) The term “flammable” is synonymous with the term “inflammable” which has been used in previous editions of BS 229.
33、 Licensed Copy: sheffieldun sheffieldun, na, Tue Nov 28 13:49:16 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 229:1957 iv BSI 10-1999 Obsolescent (by Amendment No. 9) This standard has been declared obsolescent. It is not recommended for new designs of apparatus but is retained to provide a standar
34、d for servicing existing equipment and installations. BS 4683-2 is a later standard which will eventually be superseded by BS 5501-5. BS 5501-5 is identical with European Standard EN 50018 which is referred to in EEC Directives 79/196/EEC and 82/130/EEC. A British Standard does not purport to includ
35、e 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
36、 to iv, pages 1 to 34 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: sheffieldun sheffieldun, na, Tue Nov 28 13:49:16 GMT+00:00 2006, Uncontrolled
37、Copy, (c) BSI BS 229:1957 BSI 10-19991 Section 1. General 1 Scope This standard prescribes the performance required from the flameproof enclosure of electrical apparatus and those features of design and construction which are considered to be essential or desirable to secure reliability of the enclo
38、sure in service. Pending the revision of existing British Standards for particular types of flameproof apparatus to make them accord with this specification where applicable, this standard takes precedence over the individual standards for apparatus where there is any conflict as regards flameproof
39、requirements. For the purposes of this standard various flammable gases and vapours which constitute an explosion hazard in industry are placed in groups according to the appropriate maximum permissible dimensions of joint gaps and other openings in the enclosure of the apparatus as set out in Claus
40、e 4, Table 1. It is intended to add to this list of gases and vapours when the necessary information is available. It will be seen that in the Group IV are placed those gases and vapours with regard to which the maximum safe gap, as at present ascertained, is too small to be practicable for the gene
41、rality of apparatus and to justify certification on the basis of type test. NOTEIt is not intended that this standard shall be applicable to apparatus certified as flameproof by the recognized Testing Authority before the date of this publication; but where provisional reports have been issued by th
42、at authority, it is to be understood that certificates when issued in substitution for such provisional reports will require compliance with the relevant dimensions in Table 1. 2 Definition of flameproof enclosure A flameproof enclosure for electrical apparatus is one that will withstand, without in
43、jury, any explosion of the prescribed flammable gas that may occur within it under practical conditions of operation within the rating of the apparatus (and recognized overloads, if any, associated therewith), and will prevent the transmission of flame such as will ignite the prescribed flammable ga
44、s which may be present in the surrounding atmosphere. NOTE 1Flammable gases. Flammable gas may originate within the enclosure of particular kinds of apparatus, such as gases derived from the cracking of hydrocarbon oil under the action of the electric arc in oil-immersed switch and control gear. The
45、 flammable gases within and without the enclosure may differ in such cases, and limiting dimensions appropriate to these different flammable gases are prescribed for joint surfaces and other openings in the flameproof enclosure. NOTE 2Control of circuit. As the condition of flameproofness depends up
46、on operation of the apparatus within its rating, means should be provided so that the highest recognized overload of the apparatus or, in the case of circuit-breakers, the rated breaking capacity, is not exceeded. The consequences of a destructive short-circuit within the apparatus should be guarded
47、 against by the provision of means to achieve automatic interruption of the short-circuit elsewhere before the risk of destruction of the enclosure supervenes. NOTE 3Oil-immersed resistors. If an oil-immersed starting resistor is left in circuit, or is operated more frequently than the design provid
48、es for, the temperature of the oil may increase dangerously and vapour may issue through openings of the prescribed dimensions in the enclosing case at such a temperature as to ignite spontaneously when mixed with air. NOTE 4Normal operating temperature. The normal operating temperature of some appa
49、ratus, in particular resistors, space heaters and lighting fittings, may cause the enclosure surface to exceed the safe temperature for certain flammable substances. For instance, the Cellulose Solutions Regulations, 1934 (S.R. and O. 1934, No. 990) put the danger point for the solid residue at 180 F (82 C). There may be other cases where precautions should be taken, e.g. with regard to the vapour of diethyl ether. In cases of doubt, expert advice should be sought. NOTE 5Maintenance of structure. As the condition of flame
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