TGIFire Code Friday! What good are fire rated doors and hardware if smoke and fire can sneak through gaps? NFPA 80 provides the required measurements that prevent those gaps to allow fire to spread. Clearance under the bottom of the door (4.8.4) can be no more than 3/4 inch. Clearance between the door and frame (6.3.1.7) can be 1/16″ to 3/16″ if the door is steel. Wood doors have a maximum clearance of 1/8″.
