AbstractA mathematical Model for estimating the time available for safe egress from a fire is formulated. The model simulates the conditions which develop during the course of an enclosure fire. Since life safety considerations are primary, the simulation model which is adopted focuses attention only on phenomena which develop between the times of fire ignition and onset of hazardous conditions. This allows significant simplifications in modeling which may not be otherwise justified. Using computed variables of a simulated fire scenario of interest, times of fire detection and onset of hazard which are deduced from realistic detection and hazard criteria would be estimated. The Available Safe Egress Time (ASET) would be defined as the length of the time interval which separates these two events. Quantitative specifications for a variety of detection and hazard criteria are identified. Results of exercising the model are presented, and ASET estimates are obtained for a wide variety of realistic fire scenarios. A comparison between experimental results of a multi‐room fire test and prediction of the single‐room model suggest that the model has potential utility in providing practical simulations of multi‐room fire environ