The occupant load describes the number of square feet allocated to each person within a building. The calculation of occupant load depends on the anticipated density of people for a particular area, according to its use. It is calculated differently for different parts of a building or different types of establishments. You can use the National Fire Protection Association's life safety code as a frame of reference when calculating the building's expected occupant load. The expected occupant load requirements can be increased if the number of exits in that area are increased.
Calculate the net area of the building. As an example, the area taken up by storage areas and large objects such as pool tables should be subtracted from the gross area of the building to calculate the net area.
Calculate the number of expected occupants in different areas of the building. As an example, if the building will house a school, count the number of students that you expect to seat in the auditorium.
Consult the National Fire Protection Association's Life Safety Code to determine the number of recommended people per square ft. in each area of the building based on anticipated building use. Divide the net area of the building by the recommended people per square feet to get the value of expected occupant load.