If you are responsible for inspecting fire door assemblies or keeping them code-compliant, you already know that one of the most common challenges is related to clearances around the perimeter and at the meeting stiles of pairs.  NFPA 80 – Standard for Fire Doors and Other Opening Protectives, limits clearances for fire door assemblies to the following:

  • Clearance at the head, jambs, and meeting stiles of pairs:
    • Hollow metal doors: 1/8 inch +/- 1/16 inch, maximum
    • High-pressure decorative laminate (HPDL)-faced doors, 1/3-hour-rated flush wood doors, and stile and rail wood doors installed in hollow metal door frames: 1/8 inch +/- 1/16 inch, maximum
    • HPDL-faced doors, flush wood doors, and stile and rail wood doors with fire ratings greater than 1/3 hour: 1/8 inch, maximum
    • Door leaves constructed of other materials: 1/8 inch, maximum, unless otherwise permitted in the door, frame, and latching hardware manufacturers’ published listings
  • Clearance at the bottom of the door:
    • 3/4 inch, maximum, measured from the bottom of the door to the top of the finished floor or threshold
    • 3/8 inch, maximum, or as specified by the manufacturer’s label service procedure, if the bottom of the door is located more than 38 inches above the finished floor (ex. access door or counter shutter)
    • Where latches of the hardware project from the bottom of the door, clearance must be in accordance with the hardware manufacturer’s installation instructions – not to exceed 3/4 inch.
    • Where a threshold is installed, clearance shall be in accordance with the hardware manufacturer’s installation instructions and listings.

These tolerances are often difficult to maintain over time, but in order for fire doors to perform as designed and tested, the clearances must be compliant.  Recent testing illustrated that increasing the allowable clearance dimensions could negatively impact the assembly’s performance during a fire.  Given the importance of fire door assemblies as part of a building’s passive fire protection system and the role that proper clearances play, we need some help from you.

Please comment if you have experience with oversized clearances on fire door assemblies.  WWYD?

You need to login or register to bookmark/favorite this content.