Probabilistic risk assessment for evacuees in building fires

A probabilistic risk assessment method for evacuees in building fires is presented with consideration of some deterministic and stochastic factors. The time-dependent event tree technique is used to analyze probable fire scenarios based on operational reliability of fire protection systems. For a fire scenario, the time to untenable conditions is characterized by probability distribution with consideration of some uncertainties of design fire. Moreover, occupant pre-movement time, one of the most important proportions of evacuation time, is characterized by normal distribution to express its uncertainty. Based on calculated results of ASET and RSET for every fire scenarios, the expected number of casualties is obtained when untenable conditions occur. Moreover, according to some fire statistical data, expected risk to life (ERL) is calculated to express the risk severity. Finally, a case study for a supermarket building is presented to express the risk assessment method in detail.