1、BRITISH STANDARD BS 476-32: 1989 Fire tests on building materials and structures Part 32: Guide to full scale fire tests within buildings UDC 614.841.332:620.1:69.01BS476-32:1989 This British Standard, having been prepared under the direction of the Fire Standards Policy Committee, waspublished unde
2、r the authorityof the Board of BSI andcomes into effect on 30 November 1989 BSI 02-1999 The following BSI references relate to the work on this standard: Committee reference FSM/1 Draft for comment 87/41174 DC ISBN 0 580 17617 7 Committees responsible for this British Standard The preparation of thi
3、s British Standard was entrusted by the Fire Standards Policy Committee (FSM/-) to Technical Committee FSM/1, upon which the following bodies were represented: Association of British Roofing Felt Electricity Supply Industry in England and Manufacturers Wales Association of Building Component Enginee
4、ring Equipment and Materials Users Manufacturers Ltd. Association Association of Structural Fire Protection Eurisol (UK, Mineral Wool Association Contractors and Manufacturers Fibre Building Board Organisation (FIDOR) British Cement Association Fibre Cement Manufacturers Association British Fire Ser
5、vices Association Limited British Floor Covering Manufacturers Fire Protection Association Association Flat Glass Manufacturers Association British Plastics Federation Flat Roofing Contractors Advisory Board British Railways Board Gypsum Products Development Association British Rigid Urethane Foam M
6、anufacturers Home Office Association Institution of Fire Engineers British Wood Preserving Association Loss Prevention Council Chemical Industries Association Mastic Asphalt Council and Employers Chief and Assistant Chief Fire Officers Federation Association National Council of Building Materials Co
7、ncrete Society Producers Department of Education and Science RAPRA Technology Ltd. Department of the Environment (Building Royal Institute of British Architects Research Establishment) Steel Construction Institute Department of the Environment Timber Research and Development (Construction Industries
8、 Directorate) Association Department of the Environment United Kingdom Atomic Energy Authority (Property Services Agency) Warrington Fire Research Centre Department of the Environment for Northern Wood Wool Slab Manufacturers Ireland Association Department of Transport (Marine Directorate) Yarsley T
9、echnical Centre Ltd. The following bodies were also represented in the drafting of the standard, through subcommittees and panels: Autoclaved Aerated Concrete Products Queen Mary College Industrial Research Association Thermal Insulation Manufacturers and London Scientific Services Suppliers Associa
10、tion (TIMSA) National GRP Construction Federation University College London Phenolic Foam Manufacturers Association Amendments issued since publication Amd. No. Date of issue CommentsBS 476-32:1989 BSI 02-1999 i Contents Page Committees responsible Inside front cover Foreword ii 1 Scope 1 2 General
11、1 3 Definitions 1 4 Design and configuration 1 5 Specimens 3 6 Ignition sources 4 7 Monitoring 5 8 Safety precautions 10 9 Data recording 10 10 Test report 11 Appendix A Fire test facilities 13 Figure 1 Fire test facilities 13 Publications referred to Inside back coverBS476-32:1989 ii BSI 02-1999 Fo
12、reword This Part of BS 476 has been prepared under the direction of the Fire Standards Policy Committee. The guide does not conflict with the concept or recommendations of the ISO/TC92, Fire tests on building materials and structures, proposal DP 9705 “Room fire test in full scale for surface produc
13、ts” which specifies one configuration of test rig and one degree of ventilation. This proposal is being developed to standardize a test method for the fire performance of surface products under closely specified conditions. This guide is designed to enable a quantitative assessment to be made of the
14、 fire behaviour of a given specimen or a total interacting system, based on sound experimental practice and scientific principles. It will help to eliminate the risk of providing an incorrect assessment of a product such as may inadvertently occur if data from tests based on a limited range of exper
15、imental variables are extrapolated to other situations which are not directly comparable. The complete programme for any test series of full scale enclosed fire experiments usually involves many different considerations and possible simulations. This guide reflects the current state of knowledge and
16、 suggests a choice of geometry, ignition sources, ventilation and similar aspects of the experiment, not all of which will be appropriate to every test situation. Because of the developments in measuring techniques, this Part of BS476 has been couched in terms of advisory rather than mandatory state
17、ments in order to allow the use of up-to-date techniques as they become available. 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 itsel
18、f confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, pages 1 to 14, 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 in
19、dicated in the amendment table on the inside front cover.BS 476-32:1989 BSI 02-1999 1 1 Scope This Part of BS 476 provides comprehensive recommendations on the conduct of full scale experiments simulating fires in buildings. Such tests, of varying scale and configuration, can be used to evaluate the
20、 behaviour of building components, assemblies or constructions and/or contents under actual fire conditions. The advice on experimental design and instrumentation and the analysis and reporting of results provides a basis for a consumer/contractor agreement for the execution of ad hoc work. The guid
21、e may be used to establish, as far as is reasonably possible, laboratory conditions that represent a specific set of fire conditions, with an emphasis on examination of the pre-flashover behaviour and contribution to fire growth of the product(s) under consideration. The choice of ignition source an
22、d test construction is based on the objective of the fire experiment which may be: a) a comparison of the fire performance of different materials; b) a comparison of theory and experiment; c) a simulation experiment; d) a measurement of the fire behaviour of composites, assemblies and finished produ
23、cts; e) an investigation of the interaction of components within the system; f) an authentication of fire properties measured in small scale tests. 2 Definitions For the purposes of this Part of BS 476, the definitions given in BS4422 apply, together with the following. 2.1 closed test arrangement a
24、 form of compartment, capable of imposing a restriction on ventilation at some stage during a fire 2.2 open test arrangement a form of compartment which enables unrestricted ventilation to the fire throughout the duration of the test 2.3 associated construction a form of construction that may be req
25、uired for the testing of some elements of construction and to which the test specimen is connected, e.g. the wall into which a glazed element would be fitted 2.4 test construction a complete assembly of a specimen and any associated construction 2.5 pilot ignition ignition by a small flame or spark
26、of the flammable mixture of air and decomposition volatiles evolved from a heated combustible material that may accumulate above its surface 2.6 spontaneous ignition ignition of the flammable mixture of air and decomposition volatiles evolved from the heated material that may accumulate above its su
27、rface without provision of additional energy from spark or flame once the flammable mixture attains its spontaneous ignition temperature 2.7 critical exposure the minimum irradiance at which ignition (pilot or spontaneous as specified) can be effected, regardless of duration 3 General If only one te
28、st is envisaged, it is preferable to carry out tests in the most severe conditions likely to be encountered including position, orientation and size of ignition source. For example, for wall lining materials the interrelationship between walls, ceilings and ignition source needs careful consideratio
29、n. Positioning an ignition source in the corner of a test arrangement is recommended if it is the most severe condition. In such a case, additional side wall tests, with the ignition source placed against a plain wall arrangement would not be required, but if it is suspected that such an arrangement
30、 would significantly affect behaviour, then such tests would be necessary. It is thus essential to carry out tests on walls and ceilings in the most stringent arrangement foreseeable. Because of difficulty which might arise from variable weather conditions, it is recommended that full scale tests be
31、 carried out within an adequately dimensioned, roofed enclosure. 4 Design and configuration 4.1 General Configuration of specimens and ignition sources is of importance in a large scale fire test; compartment geometry and ventilation have major effects on test results.BS476-32:1989 2 BSI 02-1999 In
32、general the test should be carried out full scale. If this is impracticable the scale should be as large as possible and particular care is needed with interpretation of results. Physical and mechanical fixings and jointing elements which are likely to be used in practice should be incorporated in t
33、he specimen in full scale in order to establish the effect of such products under fire conditions. The minimum height of the test rig should be normal storey height (2.3m) but it may be necessary to exceed this dimension. The ratio between the height and lateral dimensions of the test rig should be
34、realistic. Normally there should be no scaling of thickness although if this is necessary the minimum thickness of the test rig should be such that there is no change in the thermal effects on fixings nor significant differences in heat loss to the surroundings during the early stages of a test. The
35、re should be no scaling of surface irregularities. With regard to ignition sources there should be no scaling in terms of impingement area, thermal severity, or application time, although with experience, it may be possible to introduce time limits. It is important to avoid limiting ventilation too
36、severely. Vents should be either to the full height of the test rig, or to door height, whichever is preferred. The latter arrangement will cause a concentration of hot gases in the upper part of the test room. The size of vent may prevent or delay flashover. In situations where it is necessary to u
37、se a closed test arrangement, vent area should be representative of full scale so that results can be indicative of performance in practice. Such tests require additional safety measures due to explosibility problems, such as careful monitoring of temperatures and remote venting and exhaust extracti
38、on after the fire is considered to be extinguished (see 4.4.2). The choice of configuration of the test facility depends on the above considerations and on the required fire scenario. The alternative configurations given in Appendix A provide a sufficiently wide range to take account of these points
39、. 4.2 Size and shape of compartment The compartment size, shape and openings should be chosen to simulate the nature or type of compartment in which the subject material, product, or system is expected to be used in actual service. If there is a range of sizes, then account should be taken of the fa
40、ct that for a given ignition exposure, the smaller compartment sizes will usually provide the most severe fire development conditions. Preferably the compartment should be designed to be symmetrical and as simple as possible for ease of analysis. The test construction could be a wall system or a lin
41、ing applied to an appropriate realistic support but it has to be noted that the results of the test will only apply to that particular combination and care would be needed with the application of those results to systems with variants of that tested. The floor of the test rig should have thermal pro
42、perties approximately equal to those which will be encountered in use. The roof/ceiling of the test rig should be flat, unless a sloping roof/ceiling is being investigated. If the actual roof/ceiling is not being subjected to test, the roof/ceiling used in the test should have thermal properties app
43、roximately equal to those which will be encountered in use. In a test for linings with unrestricted ventilation the horizontal dimensions of the specimen may be scaled down and are of less importance than the vertical dimensions, although the horizontal dimensions should be sufficient to contain the
44、 ignition source and obtain information on fire spread, including spread across junctions. A full height rig with a 1 : 1 ratio of height to horizontal length on both sides of the corner would usually be the minimum required. The arbitrary decisions made when designing an enclosed test will influenc
45、e the behaviour in the test and therefore the ranking order of the material performance. It is desirable that flexibility of test configuration is maintained but ISO is developing a test with precise requirements for dimensions and if such a closed test is required on a standard basis then use shoul
46、d be made of the ISO test (ISO/DP9705). 4.3 Thermal and radiative properties of associated construction The thermal conductivity, density and heat capacity of the wall lining will affect the rate of fire growth within the test structure. The test structure therefore should be representative of those
47、 materials with which the structure will be used in practice and should not influence the fire behaviour of the material under test in an unrealistic way.BS 476-32:1989 BSI 02-1999 3 During the course of a compartment fire experiment disintegration or cracking of the materials lining the compartment
48、 may affect the behaviour of the fire. In a confined fire test, the vertical pressure gradient developed in the presence of the fire will cause smoke and hot gases to leak to the outside, and cool air to be drawn into the compartment through the cracks in the compartment walls or specimens. The effe
49、ct of the leakage of hot gases or air will result in lower gas temperatures and reduced smoke density than would occur without leakage. This effect often causes pulsations in burning rate and temperatures. 4.4 Ventilation 4.4.1 In an open fire test, characterized by an uncontrolled and unrestricted degree of ventilation, the structure should not compromise the basic aim of realism and it is important to ensure an essentially draught-free test environment. In general, where the air supply is plentiful (high ventilation), the resulting fire will have a rapid growth rate
