Fire Door Failed Inspection? Fix the Bottom Gap Problem

If your fire-rated commercial door failed inspection, one of the most common reasonsis excessive bottom door clearance. Fire doors are required to maintain controlledgaps to prevent smoke and flame spread during a fire event.

The good news is that most fire door inspection failures related to bottom clearancecan be corrected using the proper fire-rated commercial door threshold.

Why Fire Doors Fail Inspection at the Bottom

• Door bottom gap exceeds allowable clearance
• Missing threshold at rated opening
• Improper replacement door installation
• Floor surface changes after construction
• Worn or removed threshold
• Non-listed sealing components installed

NFPA 80 Bottom Gap Requirements (Quick Reference)

When the gap exceeds allowable limits, inspectors typically require correctionbefore approving the opening.

Step 1 - Measure the Fire Door Bottom Gap

• Close the door completely
• Measure floor to bottom of door
• Check hinge side, center, and latch side
• Use the largest measurement

Approved Solutions to Fix Fire Door Bottom Clearance

Common Mistakes That Keep Failing Fire Inspections

• Adding non-rated thresholds
• Installing field-modified components
• Ignoring uneven floor conditions
• Attempting seal-only fixes without correcting clearance
• Using ADA-only solutions on rated openings

When Fire + ADA Requirements Overlap

Many public openings must satisfy both fire rating andADA accessibility. Selecting compatible listed componentshelps avoid repeat inspection failures.

Shop Commercial Door Threshold Solutions

• Commercial Door Threshold Master Hub
• Fire Rated Thresholds
• Tall / High Profile Thresholds

Related Commercial Door Problems

• Fix Gap Under Commercial Door
• Commercial Door Failed ADA Inspection
• Water Leaking Under Commercial Door
• Commercial Door Won’t Pass Inspection