Have you ever noticed a sign stating the maximum occupant load of a room? How about a sign stating that the maximum occupant load is 49 people? I’ve seen several signs stating the 49-person limit, and I recently received a question that made me ponder this.
The question was about a new residential high-rise; the top floor plan included two assembly spaces measuring almost 4,000 square feet in total, as well as some other common areas and several dwelling units. The architect indicated that panic hardware would not be required on the doors serving the assembly spaces, because the occupant load would be posted at 49 occupants for each area. When the occupant load is more than 49, the IBC requires a second means of egress and outswinging doors, and when it’s an assembly occupancy the IBC requires panic hardware.
This seems like a risky plan, especially since one of the assembly spaces exits through the other assembly space, so one door is accommodating the occupant load of both spaces. The IBC includes some exceptions for small assembly occupancies that are part of another use group (more info on that here), but the spaces in question don’t meet the criteria for those exceptions.
If we calculate the occupant load of a 4,000-square-foot assembly space using the occupant load factor for unconcentrated use (15 square feet per person), the calculated occupant load is 267 people (here’s how you calculate it). While it’s unlikely that this many people will be present on a regular basis, it’s possible that a resident could use these spaces for a party and have well over 49 occupants. Since this area is not likely to be staffed at all times by building personnel, who is going to enforce the posted occupant load limit?
I checked the IBC to see what it says about posting the occupant load:
1004.1.2 Areas without fixed seating. The number of occupants shall be computed at the rate of one occupant per unit of area as prescribed in Table 1004.1.2. For areas without fixed seating, the occupant load shall be not less than that number determined by dividing the floor area under consideration by the occupant load factor assigned to the function of the space as set forth in Table 1004.1.2. Where an intended function is not listed in Table 1004.1.2, the building official shall establish a function based on a listed function that most nearly resembles the intended function.
Exception: Where approved by the building official, the actual number of occupants for whom each occupied space, floor or building is designed, although less than those determined by calculation, shall be permitted to be used in the determination of the design occupant load.
According to the IBC, an occupant load that is lower than the calculated occupant load can be posted “where approved by the building official.” I don’t know too many AHJs who would approve a posted occupant load that is so much less than the calculated occupant load.