NFPA 80 (Standard for Fire Doors and Other Opening Protectives) sets requirements for fire door construction and installation. It specifies that the maximum undercut clearance is 3/4 inch unless otherwise tested and listed. Greater clearances compromise the integrity of the fire barrier.
Chosen Answer:
This is a voting comment (?). You can switch to a simple comment. It is better to Upvote an existing comment if you don't have anything to add.
Submit