1、BRITISH STANDARD BS ISO TR 11925-1:1999 Reaction to fire tests Ignitability of building products subjected to direct impingement of flame Part 1: Guidance on ignitability ICS 13.220.50BSISOTR11925-1:1999 This British Standard, having been prepared under the directionof the Health and Environment Sec
2、tor Committeewas published underthe authority of the Standards Committee and comesinto effect on 15 October 1999 BSI 04-2000 ISBN 0 580 35277 3 National foreword This British Standard reproduces verbatim ISO TR 11925-1:1999 and implements it as the UK national standard. The UK participation in its p
3、reparation was entrusted by Technical Committee FSH/21, Reaction to fire tests, to Subcommittee FSH/21/2, Ignitability tests, which has the responsibility to: aid enquirers to understand the text; present to the responsible international/European committee any enquiries on the interpretation, or pro
4、posals for change, and keep the UK interests informed; monitor related international and European developments and promulgate them in the UK. A list of organizations represented on this subcommittee can be obtained on request to its secretary. Cross-references The British Standards which implement i
5、nternational publications referred to in this document may be found in the BSI Standards Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Find” facility of the BSI Standards Electronic Catalogue. A British Standard does not purport to include all
6、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 and i
7、i, theISO/TR title page, pages ii to iv, pages 1 to 28, an inside back cover and aback 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. Amendments issued since publication Amd
8、. No. Date CommentsBSISOTR11925-1:1999 BSI 04-2000 i Contents Page National foreword Inside front cover Foreword iii Text of ISO/TR 11925-1 1ii blankBSISOTR11925-1:1999 ii BSI 04-2000 Contents Page Foreword ii Introduction 1 1 Scope 2 2 References 2 3 Typical“real fire” ignition sources 2 3.1 Genera
9、l 2 3.2 Characteristics of flame sources 3 3.3 Characteristics of electrical sources 4 3.4 Characteristics of radiative sources 5 4 Factors affecting ignitability tests 5 4.1 General 5 4.2 Type of heat source 5 4.2.1 Gas burners 6 4.2.2 Liquid pool fires 6 4.2.3 Solid fuels 6 4.2.4 Radiative sources
10、 6 4.2.5 Electrical sources 7 4.2.6 Smouldering sources 7 4.3 Size 7 4.4 Location 7 4.5 Physical and chemical response of exposed material 8 5 Ignitability tests 8 5.1 Radiative sources 8 5.1.1 Electrical 8 5.1.2 Gaseous 9 5.2 Flame sources 10 5.2.1 Diffusion flames 10 5.2.2 Premixed flames 10 5.3 C
11、omparison of ignition sources of ISO/TC 92/SC 1 tests 11 5.3.1 Characteristics of radiative sources 11 5.3.2 Characteristics of ISO 11925 and ISO 9705 flame sources 11 6 Models for the piloted ignition of solids 12 6.1 Introduction and general review 12 6.2 Power laws and the critical irradiance for
12、 ignition 13 6.3 Thermal thickness and substrate effects 13 6.4 Variables affecting ignitability 14 6.5 Comparisons of experimental methods 14 6.5.1 Radiative sources 14 6.5.2 Flame sources 14 Annex A Guidelines for the development of ignition source for fire tests 28 Annex B Bibliography Inside bac
13、k cover Figure 1 a) Specimen support framework and radiator cone 15 Figure 1 b) Radiator cone 16 Figure 2 Cone heater 17 Figure 3 Schematic of apparatus with ignition specimen 18 Figure 4 Apparatus specified in ISO 5458-2 19 Figure 5 a) Intermediate-scale calorimeter 20 Figure 5 b) Heat shield 21 Fi
14、gure 6 Radiant panel apparatus (ISO 9239) 22 Figure 7 Burner for ignition sources E and F (ISO 11925-3) 23BSISOTR11925-1:1999 BSI 04-2000 iii Page Figure 8 Recommended sand burner (ISO 9705) 24 Figure 9 Alternative ignition source (ISO 9705) 25 Figure 10 Burner (ISO 11925-2) 26 Figure 11 Premixed bu
15、rner for sources G and H (ISO 11925-3) 27 Table 1 4 Table 2 11 Table 3 11BSISOTR11925-1:1999 iv BSI 04-2000 Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is n
16、ormally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part i
17、n the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. Technical Reports are drafted in accordance with the rules given in the ISO/IEC Directives, Part 3. The main task of technical committees is to prepare In
18、ternational Standards, but in exceptional circumstances, a technical committee may propose the publication of a Technical Report of one of the following types: type 1, when the required support cannot be obtained for the publication of an International Standard, despite repeated efforts; type 2, whe
19、n the subject is still under technical development or where for any other reason there is the future but not immediate possibility of an agreement on an International Standard; type 3, when a technical committee has collected data of a different kind from that which is normally published as an Inter
20、national Standard (“state of the art”, for example). Technical Reports of types 1 and 2 are subject to review within three years of publication, to decide whether they can be transformed into International Standards. Technical Reports of type 3 do not necessarily have to be reviewed until the data t
21、hey provide are considered to be no longer valid or useful. ISO/TR 11925-1, which is a Technical Report of type 3, was prepared by Technical Committee ISO/TC 92, Fire safety, Subcommittee SC 1, Reaction to fire. ISO/TR 11925 consists of the following parts, under the general title Reaction to fire t
22、ests Ignitability of building products subjected to direct impingement of flame: Part 1: Guidance on ignitability; Part 2: Single flame source test; Part 3: Multi-source test.BSISOTR11925-1:1999 BSI 04-2000 1 Introduction Ignitability of materials is of basic importance when fire hazard is analysed
23、because of two reasons: First, at the initiation of a fire some object or local area is ignited, and second, during the fire growth period ignitability is an essential factor in fire spread to the other parts of a room or compartment. In buildings the structural, lining and furnishing materials are
24、solids, which require external heating to achieve flaming combustion. The ignition condition can be characterized by the minimum surface temperature at which the flow of volatiles is sufficient for sustained flaming. However, the difference in these temperatures between materials is not large. Hence
25、 it is usually more important to take into account the time of exposure and the thermal properties of the material when assessing risk of ignition. When a material is exposed to an external heat flux (radiative, convective, conductive or a combination), its surface temperature starts to rise. The te
26、mperature inside the solid also increases with time, but at a slower rate. Provided the net flux into the material is sufficiently high, eventually the surface temperature reaches a level at which pyrolysis begins. The vapours generated emerge through the exposed surface and mix with air in the boun
27、dary layer. Under certain conditions this mixture exceeds the lower flammability limit and ignites. The initiation of flaming combustion as described above is termed flaming ignition. For some materials or under certain conditions, combustion is not in the gas phase but in the solid phase. In such c
28、ases no flame can be observed and the surface is glowing. This quite different phenomenon is termed smouldering ignition. The definition of ignition has been debated in many fora. It is most usually defined as the presence of a flame on a surface, or more simply the persistence of flame. Some docume
29、nts try to subdivide the ignition process in three ways: flashing (less than 1s of flaming); transient ignition (greater than 1s and less than4s); and sustained ignition (more than 4s of flame). Other documents define ignition as the persistence of flame for greater than 10s. Many of the definitions
30、 have been derived from apparatus-dependent parameters. All definitions have their merits and all have been well discussed. This Technical Report describes and characterizes the “real fire” ignition sources, the ignition sources used in the testing of materials and products, and any correlation betw
31、een those and “real fire” sources. Some of the theoretical principles of ignition and ignitability are also addressed. The majority of ignitability tests used internationally are based on the direct application of a flame. A few tests involve radiative heating of the material but generally also requ
32、ire some form of pilot source whether a flame or a spark. In general the ignition sources used have some relevance to end-use hazard. ISO/TC 92/SC 1 has concentrated on the development of tests to simulate ignitability by a range of flame sources of increasing size and also a piloted (by flame) radi
33、ative ignition source, see ISO 11925-2 and ISO11925-3 and ISO 5657, respectively. The guidance given in this Technical Report should enable choice of the appropriate ignition source when related to the end-use application of the material or product being assessed. A comprehensive review of piloted i
34、gnition and ignitability test methods is also given in ISO/TR 11696-1. ISO 11093 also provides a brief description for a number (13) of different types of ignition source and is a reference document for persons seeking descriptions of the standardized source apparatusBSISOTR11925-1:1999 2 BSI 04-200
35、0 1 Scope This Technical Report provides guidance on “ignitability” tests for building products. It describes the principles of ignitability and characterizes different ignition sources. The results of small-scale ignitability tests may be used as a component of a total hazard analysis of a specifie
36、d fire scenario. It is therefore important that the flame or radiative source chosen is fully characterized so that relevant conclusions may be made from the test results. Guidance given in this Technical Report may also have relevance to other application areas (e.g. building contents, plastics, et
37、c.) 2 References ISO 5657:1997, Reaction to fire tests Ignitability of building products using a radiant heat source. ISO 5658-2:1996, Reaction to fire tests Spread of flame Part 2: Lateral spread on building products in vertical configuration. ISO 5660-1:1993, Fire tests Reaction to fire Part 1: Ra
38、te of heat release from building products (Cone calorimeter method). ISO 9239-1:1997, Reaction to fire tests Horizontal surface spread of flame on floor-covering systems Part 1: Flame spread using a radiant heat ignition source. ISO 9705:1993, Fire tests Full scale room test for surface products. IS
39、O 10093:1998, Plastics Fire tests Standard ignition sources. ISO/TR 11696-1:, Use of reaction to fire tests Part 1: Application of results to predict fire performance of building products by mathematical modelling 1) . ISO 11925-2:1997, Reaction to fire tests Ignitability of building products subjec
40、ted to direct impingement of flame Part 2: Single flame source test. ISO 11925-3:1997, Reaction to fire tests Ignitability of building products subjected to direct impingement of flame Part 3: Multisource test. 3 Typical “real fire” ignition sources 3.1 General Fires are caused by a wide range of ig
41、nition sources. Statistical analysis of real fires conducted in many countries has identified the most common primary and secondary sources especially in fires within buildings. The most frequent sources of fires may be the following. a) Cooking appliances (electric and gas) b) Space heating applian
42、ces (electric, gas and solid fuel) c) Electrical wiring d) Other electrical appliances (such as washing machines, bedwarmers, televisions, water heaters) e) Cigarettes f) Matches and smokers gas lighters g) Blow lamps, blow torches and welding torches, hot metal h) Rubbish burning, e.g. in waste pap
43、er baskets or in bins or accumulated piles i) Candles The items first ignited are probably the following. a) Food including cooking fat b) Gases, i.e. mains gas and bottled gasses c) Liquids, e.g. petroleum, paint spirits d) Textiles, e.g. clothing, curtains e) Upholstery, e.g. chairs, beds, sofas,
44、etc. f) Floorcoverings 1) To be published.BSISOTR11925-1:1999 BSI 04-2000 3 g) Building structures, e.g. wall linings, ceilings, partitions. h) Electrical wiring Smouldering ignition sources are particularly insidious in real fire situations since they can involve a considerable induction period bef
45、ore flaming combustion develops. In general, the real source is used in standardized tests (e.g. the cigarette, which is defined in terms of its burning rate). Primary ignition sources (i.e. sources which directly cause ignition), range from relatively common sources such as matches to fires ignited
46、 from radiant heaters. Gas flames (e.g. cigarette lighters, welding torches etc.) can also cause fires if carelessly used. Gas or electric radiant heaters may raise the temperature of materials above their flash or self-ignition temperatures. Radiant heaters can cause ignition by radiant heat alone.
47、 Other radiant heat sources include electric light bulbs which can cause high local temperatures. Secondary ignition sources do not directly cause ignition but can be ignited using primary sources (e.g. matches or cigarettes) and then burn to produce a large ignition source. Secondary sources includ
48、e waste paper baskets, newspapers or journals, clothing, loose furnishings, upholstery, etc. These items, once themselves ignited, may then spread the fire either by direct flame impingement or by radiative and convective ignition. The list below details the type of sources in each category. a) Prim
49、ary source b) Secondary sources 3.2 Characteristics of flame sources A major consideration in the selection of the type of ignition source in any test must come from a knowledge of the real fire and its associated heat fluxes. In theory, this could range from zero to an upper value of FT 4where T is the maximum flame temperature. The maximum flame temperature for most common fuels is approximately 2300 K 1. Since the Stefan Boltzman constant F is 5,67 10 11kWm 2 K 4 , a maximum irradiance
