A Review of Current and Historical Occupant Load Factors for Mercantile Occupancies

Abstract

The determination of the occupant load of a building is often necessary as part of a fire engineering design assessment. Designers often use occupant load factors (or other equivalent terminology) to carry out this calculation typically using values taken from various published guidance or deemed-to-satisfy documents. This paper examines past and current values for mercantile occupancies that are specified in documents that are used in various jurisdictions around the world. In general three approaches are used; the occupant load factors are defined by the floor level of the building, by the type of mercantile activity within the spaces or through the application of uniform values throughout the occupancy. A simple six-storey exemplar building is used to illustrate the differences in the total occupant load and the relative number of occupants per floor when the different occupant load factor approaches are employed. Even for this simple building the occupant load differs by a factor of 4.1 and the distribution of the occupants varies noticeably between upper and lower levels depending on the particular document selected for the calculation.