Fire-resisting doorsets, as distinct from single ‘fire door’ leaves, are precisely designed and engineered component sets required to perform three main functions: Protect escape routes from the effects of fire (including smoke) so occupants can leave safely (includes lofts and conversions), protect the contents and/or structure of the building by limiting the fire spread (an insurance requirement), and permit fire fighting.

Each component plays a critical role in the doorset’s fire resistance. Unauthorised changes in specification may impair the performance of the whole doorset. Any changes from the tested specification should only be made with the approval of an appropriate expert authority, such as a UKAS-accredited testing laboratory.