This British Standard, a part of the BS 476 series, 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.
This standard 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.
Guidance to operators carrying out this method of test, the effect of thermal characteristics on the performance of assemblies, advice on the construction and preparation of test specimens, and information on the validation of this method are provided in annexes to this standard.