BRE FN8 PDF

According to statistics of fires in buildings, only a few fires grow into a fully-developed stage which is defined as "post-flashover" in fire science literature. Whenever such an undesirable event happens, the intense heat produced can cause a progressive deterioration of the structural boundaries of a compartment which might "fail" to prevent the spread of fire to adjacent compartments. Protection against such a rare event by providing sufficient fire resistance to a compartment has long been the core of fire safety codes and regulations. "Failure" occurs during the post-flashover stage when, due to intense heat, the structural boundaries of a compartment reach limiting states (conditions) and violate performance criteria relating to loadbearing capacity, integrity or thermal insulation. The object of structural fire design - the subject of this publication - is to determine the level of fire resistance period which will minimise the possibility of failure by maximising the time taken by the compartment boundaries to reach the limiting states.