Protruding objects are permitted to extend below the minimum ceiling height required by Section 1003.2 where a minimum headroom of 80 inches (2032 mm) is provided over any walking surface, including walks, corridors, aisles and passageways. In other than Group I-2 and Group I-2.1 occupancies, 50 percent of the ceiling area of a means of egress shall be permitted to be reduced in height by protruding objects.
Exception: Door closers and stops shall not reduce headroom to less than 78 inches (1981 mm).
A barrier shall be provided where the vertical clearance is less than 80 inches (2032 mm) high. The leading edge of such a barrier shall be located 27 inches (686 mm) maximum above the floor.