Fire Door Clearance Check (NFPA 80 Annual Inspection)

ScopeToo much gap and the assembly does not resist the passage of smoke and flame, and the limits are small enough that ordinary building movement puts a door outside them: a door that has dropped on its hinges, a frame that has been shimmed, or a floor covering removed after installation all move the clearance without anyone touching the door. A wood door in a pair measuring 1/8 in at the head and hinge jamb passes at the limit; 3/16 in at the strike jamb fails by 1/16 in; 1/8 in between the meeting edges passes at the limit, because NFPA 80 applies the SAME clearance at the meeting stiles as at the head and jambs (1/8 in maximum on a wood door rated over 20 minutes; 1/8 in plus or minus 1/16 in on steel); and 1 1/4 in at the bottom fails a 3/4 in limit by half an inch. TWO FAILURES, TWO DIFFERENT CAUSES. The strike jamb is a door that has settled or a frame that has moved, and it is corrected by adjusting the hinges or the frame -- not by adding a gasket, which does not restore the assembly's listing. The bottom is almost certainly a flooring change: something was removed and the door was not adjusted, and the correction is a threshold or a door bottom listed for the assembly, not a sweep chosen for draught control. The bottom clearance is measured to the FLOOR, so adding carpet or tile reduces it, which is usually fine, while removing flooring increases it, which is not. The rest of the inspection is not arithmetic and belongs beside the numbers: the label has to be legible, there can be no field modifications -- a hole drilled for a card reader voids the label unless done under the listing -- and the door must close and latch from any position, every time, with nothing blocking, wedging, or dogging it. Any one of those fails the door on its own. A clearance comparison against limits the user supplies. The limits differ by door material, construction, the specific listing, and the adopted edition of NFPA 80; the assembly's own listing governs. This is not a fire door inspection, which must be performed by a person with knowledge of the assembly's operating components, covers items well beyond clearances, and requires written records. It does not evaluate the frame, anchorage, glazing, hardware listing, or the gasketing and smoke seals. A failed fire door is a life-safety deficiency: NFPA 80, the assembly's listing, the adopted fire code, and the AHJ govern.

Formula or tableeach measured clearance is compared to its own entered limit; the margin is the limit less the measurement, and the bottom shortfall is how far the door must come down to comply.

Source and editionThe NFPA 80 fire door clearance limits by name -- ONE limit at the head, the jambs, and between the meeting stiles of a pair (steel doors and 20-minute wood doors 1/8 in plus or minus 1/16 in, so 3/16 in maximum; wood doors rated over 20 minutes 1/8 in maximum), and 3/4 in maximum from the bottom of the door to the floor -- with the assembly's own listing named as governing. Limits are entered because they differ by material, construction, listing, and adopted edition.

Free accessSubtraction on the user's own feeler-gauge readings against limits they enter; no NFPA 80 table is reproduced.

What governsEstimate. AHJ and licensed professional govern.

API field nameshead_in, hinge_jamb_in, strike_jamb_in, meeting_edge_in, bottom_in, perimeter_limit_in, meeting_limit_in, bottom_limit_in, strike_margin_in, meeting_margin_in, bottom_margin_in, failure_count, bottom_reduction_needed_in

• Clearances fail without anyone touching the door settled hinges, a shimmed frame, or removed flooring all move themNFPA 80
• A gasket does not restore a listing an over-limit jamb is corrected at the hinges or the frameNFPA 80
• The non-dimensional checks fail the door on their own label legible, no field modifications, closes and latches from any positionNFPA 80