Double-Leaf Fire Doors: Why the Closing Sequence Matters
A fire-rated door keeps a fire compartment intact only when it is fully closed and positively latched. Double-leaf fire doors are common in plant, electrical, mechanical and generator rooms, often because a wide opening is needed to move equipment, not because of occupant load.
There are two typical arrangements. In the first, an active leaf is used day to day and the inactive leaf stays secured by flush bolts; NFPA 80 recognises this for pairs used for equipment movement. In the second, both leaves can open, so a door coordinator is needed to make the inactive leaf close first and the active leaf second, letting the astragal and latches engage properly.
A door that closes in the wrong order or fails to latch gives no protection. Closers, coordinators, latches, flush bolts, hinges and astragals all form part of the tested and listed fire door assembly.
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