This Part of BS 476 specifies a method of test for measuring the lateral spread of flame along the surface of a specimen of a product orientated in the vertical position under opposed flow conditions, and a classification system based on the rate and extent of the spread of flame. It provides data suitable for comparing the end-use performances of essentially flat materials, composites or assemblies, which are used primarily as the exposed surfaces of walls or ceilings.
Annex A gives guidance to operators carrying out this method of test. Annex B discusses the effect of thermal characteristics on the performance of assemblies and gives advice on the construction and preparation of test specimens. Annex C gives information on the validation of this method.
NOTE. The test results relate only to the behaviour of the test specimens of the product under the particular conditions of test; they are not intended to be the sole criterion for assessing the potential fire hazard of the product in use.