Representing Evacuation Behavior in Engineering Terms

In performance-based analyses, engineers evaluate whether a building design and/or evacuation procedure allows occupants sufficient time to evacuate before fire conditions become untenable. Guidance exists for the calculation of the time until conditions become untenable in areas of the structure (known as the available safe egress time) during fire situations. This article presents a method for determining the amount of time required for building occupants to reach a defined point of safety (known as the required safe egress time) for a particular building design or scenario. The method requires the engineer to identify real-world factors from the building conditions/situations that influence human performance (e.g. evacuation), understand the nature of their impact on human performance and then represent this impact in terms that can be employed within evacuation model calculations. An example is also presented to demonstrate the method described here.