Making sure that a building is fire prepared is just one of the many things on a facility manager’s list of things to do. One of the best ways to make sure that a building is fire prepared is by preventing the spread of fire and smoke with fire doors. Fire doors have become an important part of a building’s passive fire protection system. Of course, in order for a fire door to properly do its job, it must be kept in the closed position with nothing blocking its access.
According to Door Security and Safety Foundation, one of the top deficiencies found in fire door inspections is “poor clearance dimensions around the perimeter of the door in the closed position”. Too often gaps around the perimeter of a fire door will be greater than the gap allowances for fire doors acceptable by NFPA 80. If the gap around the fire door is too big, then fire and smoke will be able pass through. So, then what are the gap allowances for fire doors that won’t allow fire and smoke to pass through?
NFPA 80, Section 6.3.1.7.1 – Swinging Doors with Builders Hardware
Gap Allowances for Fire Doors made of Wood:
- 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”
Gap Allowances for Fire Doors made of Steel:
- 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.
However, if a fire door does have a gap larger than what is acceptable by NFPA, then a fire rated seal will be used to help close the gap. Gaps can be sealed with an intumescent strip that when exposed to heat will expand, a neoprene weathering strip, or gaskets to help prevent the passage of smoke. Fire doors have become important to a building’s fire protection system because they help prevent the spread of fire while allowing occupants a means of escape. So, it’s important for the clearance around the perimeter of the fire door to be within the appropriate limits to help keep a building and its occupants safe.
