Does the projection of a surface-mounted strike for rim panic hardware affect the clear width of a door opening?
This is a good question, and technically, the answer depends on which set of model codes has been adopted. I would consider the strike a projection – just like panic hardware projecting off of the face of the door is a projection when measuring the clear opening width. The codes and standards state that the clear width is measured from the face of the door, not from the panic hardware.
The I-Codes allow projections of up to 4 inches into the clear opening width, between 34 inches and 80 inches above the floor. These codes require panic hardware to be mounted between 34 inches and 48 inches above the floor, so the panic and the strike would be allowable projections as long as the hardware does not project more than 4 inches. Here’s where the 2021 IBC addresses projections into the clear opening width:
1010.1.1.1 Projections into clear opening. There shall not be projections into the required clear opening width lower than 34 inches (864 mm) above the floor or ground. Projections into the clear opening width between 34 inches (864 mm) and 80 inches (2032 mm) above the floor or ground shall not exceed 4 inches (102 mm).
Exception: Door closers, overhead door stops, power door operators, and electromagnetic door locks shall be permitted to be 78 inches (1980 mm) minimum above the floor.
One complication with this interpretation is that NFPA 101 only allows projections on the hinge side of the opening, not on the strike side. With that said, I don’t know why the projection of the strike would be a problem if the projection of the panic hardware on the opposite side of the opening isn’t a problem. With regard to measuring the clear opening width, NFPA 101 says: The measurement shall be taken between the face of the door leaf and the stop of the frame. I have put this on my wish list to try to address in the next code development cycle.