The gap sizes around swinging doors can influence the fire and smoke spread through fire rated construction. The current standard (i.e. NFPA 80) prescribes that the bottom gap be no larger than 3/4 in. (19.05 mm), and the side and top gaps be no larger than 1/8 in. (3.175 mm) — with an additional 1/16 in. (1.59 mm) over-tolerance for steel doors and 1/3-hour rated wood doors installed in hollow metal doorframes.