Fire doors are complex devices and require a knowledgeable professional in the field to perform an annual inspection as accurately as NFPA 80 requires. However, one quick and easy inspection that should be regularly performed is verifying that the gaps surrounding your fire doors meet NFPA requirements. As a facility manager, this may seem like such a minor issue compared to all the other problems you have to deal with. But a minor issue could cause a major problem in the event of a fire emergency.
In order for a fire to burn it needs oxygen. A large fire in a closed room will begin to consume all the oxygen in that area, creating a vacuum of negative pressure near the base of the fire. The heat from the burning materials creates intense positive pressure near the ceiling of the room. If the gaps are too big, the negative pressure will cause fresh oxygen to be sucked into the room with the fire, feeding it and allowing it to grow bigger and hotter. This will also make the positive pressure stronger, forcing the hot air and smoke out of the higher fire door gaps and into areas that are supposed to be safe. Therefore, with properly sealed and fire resistant gaps, the fire will not have a constant supply of fresh oxygen to burn, and will burn smaller or even die out on its own.
NFPA 80, Section 6.3.1.7.1 – Swinging Doors with Builders Hardware
Wood Doors:
- Clearance for under the bottom of the door maximum is 3/4”
- Clearance between door and frame is 1/8”
- Clearance for meeting edges for a pair of doors is 1/8”
Steel Doors:
- Clearance for under the bottom of the door maximum is 3/4”
- Clearance between door and frame is 1/8”, +/- 1/16”
- Clearance for meeting edges for a pair of doors is 1/8”, +/- 1/16”
NFPA 80, Section 10.3 – Vertically Sliding Fire Doors
- Clearance between the door and the wall when the door is closed is 3/8 in.
