Door Gap Gauge

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The Door Gap Gauge is a simple to use, highly efficient “must have” tool that every inspector, fire marshal, commercial property/maintenance manager and fire department needs in their toolbox. The door gap gauge has gained popularity and can be found in use across the United States

This is a must-have tool for building inspectors, IOR’s, Fire Marshals and AHJ’s for inspection of non-rated and rated fire doors in warehouses, office buildings, hospitals, and residential high rises.

Watch the video to find out for your self that the Door Gap Gauge is a simple to use, highly efficient “must have” tool that every inspector, fire marshal, commercial property/maintenance manager and fire department needs in their toolbox.

Checking for and maintaining Fire Door compliance has not been easier with the door gap gauge.  Fire door compliance should be at the forefront of new construction and maintenance of existing facilities everywhere.


Below is a Fire Door Inspection Checklist that we have put together for maintaining fire door compliance per NFPA 80. We have also put together a Door Inspection Form for you to download.

Instructions on how to use a Door Gap Gauge.

Download All Things Inspectors Door Inspection Form

  1. Check door leaf and frames for fire door labels and make sure that they are legible.
    • Make sure the labels are legible. The door leaf label should be attached to the hinge edge of the door just below the top hinge or at the top edge of the door. A second label should be on the frame. If the labels are missing or painted over, the Authority Having Jurisdiction (AHJ) may require them replaced.
  2. Look for open holes/breaks in the door or frame.
    • Look for holes from missing, removed or incorrect fasteners.
  3. Make sure glazing, glazing beads and vision light frames are intact and securely fastened in place, if so equipped.
    • Tighten loose and replace missing fasteners. Ensure that all glazing is labeled for the fire resistance of the opening.
    • The glass should be free from damage and cracking?
    • Make sure that the glazing is fire rated and labeled accordingly.
  4. Check that the door, frame, hinges, hardware and non-combustible thresholds are secure, aligned and are in working order.
    • Verify that the face of the door is flush or slightly inset with the edge of the frame. Check that the top and bottom flush bolts project one-half inch into the strike. Look for signs of damage. Realign or repair the damage.
  5. Inspect for missing, defective or broken parts.
    • During inspections, it is common that latch bolts, and strike plates, closer arms and cover plates have not broken.
  6. With the door closed, measure door clearances around the perimeter of the door from the pull side of the door to make sure the door clearances are within allowable limits.
    • On paired doors, without overlapping astragals, measure between the meeting stiles. The clearance under the bottom of the door is generally ¾” and the top and vertical reveals are 1/8” +/- 1/16”.  You should always look for wear and tear on the frame or the door. Wear more often than not indicates poor or miss aligned margins.
  7. Open the door fully and confirm that the self-closing device is operational and completely closes and latches the door.
    • Adjust the self-closing device to achieve full closure and latching without exceeding 15 lbs. of opening force pressure.
  8. When a coordinator gets installed, confirm that the inactive and active leaves operate in the correct sequence (pairs only).
    • Open the door, then close it, observing whether the inactive leaf closes before the active leaf. If the door is not securely latching, evaluate whether it is a faulty latch bad coordinator or door misalignment.
  9. Check that the latching hardware operation secures the door when in a closed position from a self-closing position without additional help from a human.
    • Make sure that the latch secures the door in the closed position.
  10. Look for auxiliary hardware items or objects that interfere or prohibit fire door operation or closure
  11. Inspect for field modifications to the door assembly that void the fire door label.
    • Look for barrel bolts, deadbolts or kick down door holders. Remove non-compliant addons.
  12. Verify the presence and integrity of any required meeting edge protection, smoke gasketing.
    • Smoke gasketing cannot interfere with closing the door. Replace or repair as needed.
  13. Confirm that signage affixed to the door gets attached with adhesive.
    • Signage should not get attached with any mechanical fasteners or screws.
    • Signage cannot exceed five percent of the door surface.
  14. Hold Open Devices
    • Door hold opens are tied into the fire alarm and working as designed when they are required.
  15. Fire Exit Hardware
    • Make sure the hardware is Fire Exit Hardware as necessary
  16. Tools for inspecting fire rated doors.
    • There are several useful tools for checking fire door clearances quickly and accurately (much better than using a tape measure and “eyeballing” it). Purchase a  fire door gap gauge today to make your work life more efficient.
    • The Fire Door Gap Gauge is the most innovative tool to make sure your fire rated doors have the required clearance requirements per NFPA 80 on the market today.

Watch the door gap gauge video to see if the door gap is too big?

Watch the door gap gauge video to see if the door gap is too small?
If you have a fire rated door that you need to inspect.  You need to watch the video to see all the features the best door gap gauge boast.

Watch the door gap gauge video to see if the door gap is just right?