Fire Door Assemblies and Hardware
Think assembly, not door
A fire door assembly includes the door, frame, hinges, closer, latching, seals, glazing, threshold, and all attached hardware. Every component must be listed for the application and compatible with the assembly label. A common failure is a non-listed closer or exit device installed because 'it fits.' Labels must stay intact and legible; painting over a label, drilling extra holes, or cutting the door can void the listing unless the manufacturer's instructions and NFPA 80 permit it.
Hardware behavior
Closers must be adjusted so the door closes and positively latches from any open position: check sweep, latch speed, and backcheck. Positive latching means the latch engages the strike; a deadbolt or friction catch alone generally does not satisfy. Hold-opens must be listed, fail-safe, and released by the fire alarm; wedges and unlisted hooks are violations. Exit devices on fire doors must be fire-listed and release with normal force. Hinges must be labeled, of the correct type, fully screwed, and free of binding. Coordinators and flush bolts must sequence paired doors correctly.
Tolerances and traps
Typical NFPA 80 clearances are about 1/8 in. at head and jambs and a maximum 3/4 in. undercut at the floor for fire doors; smoke-control assemblies are held tighter. Question traps include testing only from a partly open position, ignoring the inactive leaf, mixing smoke and fire requirements, and assuming new hardware is automatically compliant.
Worked example: on a pair of 3 ft doors, the inactive leaf has manual flush bolts and the active leaf has a closer. Verify the coordinator closes the inactive leaf first, then the active leaf closes and latches. Rule of thumb: if a component is not labeled for the assembly, the assembly is not compliant.