Fire test methods surface flame spread

Steiner tunnel tests (ASTM E84) [127] measure the surface flame spread of a material. The specimen is exposed to an ignition source, and the rate at which the flames travel to the end of the specimen is measured. The severity of the exposure and the time a specimen is exposed to the ignition source are the main differences between the tunnel test methods [119]. The data obtained provide a measure of fire hazard, in that flame spread can transmit fire to more flammable materials in the vicinity and thus enlarge a conflagration, even though the transmitting material itself contributes little fuel to the fire. 

A description is given of the initiatives carried out within the European Community for the harmonization of fire testing. The technical and economic reasons are explained for such initiatives, which are taken in order to remove barriers to trade from the European internal market. Of the various fire aspects, only fire reaction testing is taken into consideration here, because it appears as a major technical obstacle to the free circulation of construction materials. All possible approaches are considered for the attainment of such a harmonization and one, the so called interim solution, is fully described. The proposed interim solution, is based on the adoption of three fundamental test methods, i.e. the British "Surface Spread of Flame", the French "Epiradiateur" and the German "Brandschacht", and on the use of a rather complicated "transposition document", which should allow to derive most of the national classifications from the three test package. 

A typical criticism of this test method, for example, is that ordinary newsprint, and even tissue paper, will meet its requirements. That is a valid criticism. However, there seems to be general agreement that, in spite of its lack of sophistication, this test method has been successful in eliminating the fabrics with the poorest fire performance from the general population of fabrics in use for apparel in the United States. Thus, fabric types such as the fibrous torch sweaters with raised surface fibers that ignite readily and spread flame quickly are no longer legally sold in the United States due to the test requirements. The test has also been able to screen out the use of very sheer... 

Measurement of flame spread under external heat flux is necessary where the thermal radiation is likely to impinge on the textile materials, for example, the flooring material of the building or transport vehicles whose upper surfaces are heated by flames or hot gases, or both. The French test method, NF P 92-503 Bruleur Electrique or M test involves radiant panel for testing flame spread of flexible textile materials. This test method (flame spread under external heat flux) is the basis of that used by the FAA (Federal Aviation Administration) for assessing flammability of textile composites used in thermal/acoustic insulation materials (FAR 25.856 (a)) used in aircraft and has also been included by the EU for fire test approval of floorings such as prEN ISO 9239 and BS ISO 4589-1. 

BS 476 Part 7 1987 Fire tests on building materials and structures Method for classification of the surface spread of flame of products. 

Fire retardant n. Descriptive term which impUes that the described product, under accepted methods of test, will significantly (a) Reduce the rate of flame spread on the surface of a material to which it has been applied, (b) Resist ignition when exposed to high temperatures, (c) Insulate a substrate to which it has been applied and prolong the time required to reach its ignition, melting, or structural-weakening temperature. 

Materials are tested by insurance bodies and fire research establishments. The purpose of the tests is to classify materials according to the tendency for flame to spread over their surfaces. As with all standardized test methods, care must be taken when applying test results to real applications. 

ASTM E132 was developed as an improvement on the apparatus in ASTM E162 [38]. The specimen size for flame spread studies is 155 by 800 mm by a maximum thickness of 50 mm. This test method determines the critical flux for flame spread, the surface temperature needed for flame spread and the thermal inertia or thermal heating property (product of the thermal conductivity) test. These properties are used mainly for assessment of fire hazard and for input into fire models. A flame spread parameter is also determined, and this can be used as a direct way of comparing the responses of the specimens. It has been used for predictions of full-scale flame performance [39]. 

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