How do you calculate occupant load under the Ontario Building Code?
Occupant load is the floor area divided by the area-per-person factor in Table 3.1.17.1, for example 0.75 m2 per person for assembly space with non-fixed seats, 1.85 m2 for classrooms and 9.3 m2 for offices, or the actual number of fixed seats.
Paraphrased for clarity — open this provision in the BUILDAiD Library for the exact wording.
Occupant load drives exit width, number of egress doorways, door swing, panic hardware, fire alarm triggers and washroom counts, so calculate it room by room rather than for the gross floor. Use net use-specific areas per the table factors and sum them along egress paths, remembering converging streams at exits. Restaurants and event spaces are frequent trouble spots, and posted occupant load signs are required for some assembly uses.
The Code estimates how many people can fill a space by dividing its area by a standard amount of room per person, tighter for a banquet hall, roomier for an office. That head count then sizes the doors, hallways and exits.
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This page is provided for general information. Building code requirements depend on your specific project, occupancy and municipality, and code editions change. Always verify requirements against the current Ontario Building Code and confirm with your local building department.