BS 476-20-1987
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ID： |
ABDFA06122D5410590491414D9D8022F |
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文件大小(MB)： |
2.31 |
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页数： |
44 |
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文件格式： |
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日期： |
2007-2-7 |
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购买： |
文本摘录（文本识别可能有误，但文件阅览显示及打印正常，pdf文件可进行文字搜索定位）：
BS 476: Part 20:1987,UDC 614 84332 620 1 69 O1 - 699 81,■,. British Standards Institution. No part of this publication may be photocopied or otherwise reproduced without the prior permission in writing of BSI,British Standard,Fire tests on building materials ?and structures,Part 20, Method for determination of the fire resistance of elements of construction (general principles),Essais au feu des materiaux et structures du batiment,Partie 20, Methode de determination de la resistance au feu des elements de construction (principes generaux),Brandschutztechnische Priifungen an Baustoffen und Bauten,Teil 20. Verfahren zur Bestimmung des Feuerwiderstandes von Bauteilen (Allgemeines),■,British Standards Institution,BS 476: Part 20: 1987,Foreword,This Part of BS 476 has been prepared under the direction of the Fire Standards Committee and describes the general procedures and equipment required to determine the fire resistance of elements of construction. This Part should be read together with BS 476 Parts 21f 22 and 23 as appropriate which describe the detailed procedure for the testing of individual elements of construction The four Parts taken together constitute a complete revision of BS 476 . Part 8, which is withdrawn However, the latter will still be made available on request, since Jt is referred to in building regulations and other legislative documents. Parts 20 to 23 have been prepared in such a way that Part 20 will need to be used with the subsequent Parts descrrbed.,For the purposes of these Parts, elements of construction have been categorized into three main groups:,(a),loadbearing elements that have a fire resistance;,(b),non-loadbearing elements that have a f*re resistance;,(c),elements that make a contribution to the fire resistance of a structure.,The specific requrrements for the testing of these groups are described in Parts 21 to 23 respectively. Guidance and background information that wdl assist the designer and the testing authority to select and evaluate specimens that are more representative of situations in practice are given in appendices to the four Parts,The revision of BS 476 Part 8 has been prepared in order to improve repeatability and reproducibility of the results obtained by more closely defining the operating procedures and the equipment used The main changes relate to improvements in the techniques for measuring temperature, pressure and load d*stnbution. Following the pubheation of PD 6496 which analysed the differences between the requirements of BS 476 . Part 8, ISO 834, ISO 3008 and ISO 3009, and Annex 1 of the preliminary draft on an EEC Commission Directive DG 111 (document 1202, September 1977) (now replaced by EUR 8750), this revision has, where possible, adopted similar requirements to those given in the international standards, though in some cases, improvements have been made. These improvements have tended to tighten up the procedures already specified in the other standards and will therefore remain in compliance with them.,One significant change in the method is the introduction of a fixed temperature/time heating regime which assumes a notional ambient temperature rather than the use of a temperature/rise curve that is related to the actual ambient temperature at the time of the test. The reasons for this change are described in appendix A.,A further change has been the adoption of the minimum specimen sizes specified in ISO 834. Combined with this,is a greater acceptability of smaller furnaces for testing specimens of elements that are, at full size, capable of being tested in smaller furnaces. Because of the diversity of furnace designs it has not been possible to define the equipment more trghtly, although A.5 does give guidance on the points to be considered in any future furnace designs This Part has, however, eliminated the use of oil based fuels as a method of heating a fire resistance testing furnace,The differential pressure between the furnace chamber and the laboratory has been changed slightly with respect to the magnitude, the time of application and the measuring technique. This has been done in an attempt to rationalize the pressure difference requirements for all elements under test.,Following the decision of the International Organization for Standardization, Technical Committee ISO/TC 92, Fire tests on building materials, components and structures, to dispense with the use of the criterion of stability (ultimate integrity) in the fire resistance testing procedures for fire doors and glazed elements (ISO 3008 and ISO 3009 respectively! it has been decided to adopt a similar principle in this revision. It is no ……
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