Assessment of Life Safety Risk in Building Fires With an Integrated Fire and Evacuation Model

Abstract

This paper presents an integrated simulation methodology that combines fire hazard modeling with pedestrian evacuation analysis to evaluate how tenability conditions affect occupant egress. In the proposed approach, fire scenarios representative of leisure and spa resorts are modeled using the Fire Dynamics Simulator (FDS). The most critical hazards—visibility reduction, oxygen depletion, and toxic gas concentrations—were integrated as dynamic 3D, time-dependent data into evacuation simulations performed with Pathfinder. The stochastic nature of the simulations arises from variability in occupant premovement times, demographic characteristics, and walking speeds, which reflect realistic heterogeneity in evacuation behavior. The results show that poor visibility conditions reduce the available safe egress time (ASET), the time before conditions become untenable, by 55%, increase required safe egress time (RSET) by up to 26.2%, and consequently decrease the safe egress margin (the difference between ASET and RSET) by 702%. Conversely, safety systems such as sprinklers and fire doors significantly enhance egress performance, increasing ASET by 133%, reducing RSET by 3.5%, and improving the safe egress margin by 90.1% compared with scenarios without these systems. These findings demonstrate that the integrated framework not only improves the accuracy of evacuation performance assessment but also provides practical insights for real-world performance-based design. In particular, the methodology supports safer exit allocation, enhanced emergency planning, and the identification of architectural modifications that reduce evacuation risks.