A fire door assembly (installed in a fire rated wall) is used as part of a passive fire protection system to reduce the spread of fire or smoke between compartments and to enable safe egress in the event of a fire. To qualify as a fire rated opening, all of the hardware as well as the door, frame, and required smoke gasket must be listed with a testing laboratory for use on a rated fire door assembly.
Fire door assemblies are rated for 180 minutes, 90 minutes, 60 minutes, 45 minutes, and 20 minutes. The fire rating of a fire door assembly is determined by the lowest rated component; for example, a 20 minute rated door mounted in a 180 minute rated frame would be rated as 20 minute.
Temperature rise rated doors are specially designed for stairwells where door assemblies must not only be fire rated, but also limit the transmission of heat, to allow safe passage.
Fire doors must be self-closing and self-latching. In some situations, the local AHJ (Authority Having Jurisdiction) may allow doors to be automatic-closing by means of a magnetic holder or other device that releases and allows the door to close upon activation of the buildings’ fire alarm system