The occupant load for a building is based on the number of people that can be in a specific area of a building. It uses the actual square foot of a room or area multiplied by a factor indicated in the Fire Code for that type of room use. The total occupant load for a building is calculated by adding all of the various room/area occupant loads together.
Certain types of rooms are exempt from the calculation, such as a bathroom, because the bathroom would normally be occupied by someone from one of the other calculated rooms.
The occupant load indicator listed in the Fire Code is different for different types of room uses; for example, an area used for an office does not need as much room as a room where manufacturing equipment is used. The seating area of a church with fixed pews is different from the seating area of a restaurant.