Technical Booklet E Fire Safety·Page 47·2.37
Calculating occupant capacity in non-domestic buildings
Occupant capacity is determined either by a known design number or by dividing the room or storey area by the appropriate floor space factor from Table 2.2. Storey and building capacity are calculated as sums of room capacities.
In buildings other than dwellings the number of escape routes needed depends on the number of occupants (occupant capacity). In some cases a room or a storey is designed to accommodate a known number of people; in others the occupant capacity should be calculated by dividing the area of the room or storey (excluding stairways, lifts and sanitary accommodation) by the appropriate floor space factor given in Table 2.2. Where the occupant capacity is calculated for rooms the occupant capacity of a storey is the sum of the occupant capacities of the rooms on that storey. The occupant capacity of a building or part of a building is the sum of the occupant capacities of the storeys in that building or part.
Source — /Users/richardhill/Documents/planning-arch-project/data/documents/regional/Technical Booklet E - Fire Safety.pdf