Remember him? I guess I’m dating myself if I admit that I do since he made his debut in the mid- to late-80’s, right around the time that Bill Lawliss, John Gant, and I all graduated with degrees in Architecture from Vermont Technical College. Just think where we could be now if we took those drafting jobs we were offered instead of choosing the glamorous field of door hardware.
This post is not about Max Headroom…it’s about his cousin, Min(imum) Headroom. I was asked this question twice in a 3-hour period today. The minimum height for an egress door is 6′-8″ nominal, which means that you can ignore the frame stop at the head and measure the required 80″ to the door rabbet. But what about hardware that protrudes into that minimum height, like a parallel arm closer, overhead stop, auto operator, or mag-lock?
The IBC and ICC/ANSI A117.1 both allow the clear opening height to be reduced to 78″ by a door closer or overhead stop (typically measured to the arm), and in my opinion, an auto operator would qualify too. There isn’t a reference to mag-locks, so it would be up to the code official whether the mag-lock could be mounted lower than 80″ above the floor. However, according to the IBC Commentary, the 78″ dimension to the closer arm is considered reasonable, partially because “these devices are normally mounted away from the center of the door opening, thus minimizing the potential for contact with a person moving through the opening.” Since the mag-lock would be mounted toward the lock side of a single door and in the center of a pair, the code official may not allow the exception to be applied to mag-locks, especially since the exception is specific to closers and overhead stops. This would mean that the 80″ headroom must be maintained between the floor and the bottom of the mag-lock, which creates a problem on 6′-8″ doors.
Here’s where to find this code reference:
IBC 2003, 2006, 2009:
1003.3.1 Headroom. Protruding objects are permitted to extend below the minimum ceiling height required by Section 1003.2 provided a minimum headroom of 80 inches (2032 mm) shall be provided for any walking surface,
including walks, corridors, aisles and passageways. Not more than 50 percent of the ceiling area of a means of egress shall 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.
ICC/ANSI A117.1 – 2003:
404.2.2…Exception 1. Door closers and door stops shall be permitted to be 78 inches (1980 mm) minimum above the floor.