This British Standard, a part of the BS 476 series, describes a procedure for a laboratory test for the determination of fire resistance of elements of construction when subjected to defined heating and pressure conditions.
The method provides a means of quantifying the ability of elements to withstand exposure to high temperatures, by setting criteria by which the load-bearing capacity, the fire containment (integrity) and the thermal transmittance (insulation) functions can be adjudged.
A representative sample of the element is exposed to a specified regime of heating and the performance of the test sample is monitored on the basis of criteria described in the standard. Fire resistance of the test element is expressed as the time for which appropriate criteria have been satisfied. The times so obtained are a measure of the adequacy of the construction in a fire but have no direct relationship with the duration of a real fire.