Development of a time pressure-based model for the simulation of an evacuation in a fire emergency

Abstract

The study of pedestrian behaviour in a fire emergency is essential for effectively reducing the number of casualties. However, most studies only consider the effect of fire on pedestrian behaviour and ignore the effect of a fire emergency on pedestrian psychology. In this study, we introduce a method of assessing the pedestrian time pressure within a cellular automaton model using the available safe egress time and required safe egress time in fire evacuations. Moreover, a more realistic reflection of the evacuation process in a fire emergency is obtained by introducing Pyrosim to compute the fire floor field and by proposing a sequential update method based on time pressure. To assess the model, we conduct sensitivity analyses on model parameters across various environmental configurations. Numerical simulation results show that fire accelerates the evacuation rate and radiated heat transfer and temperature have the greatest effects on the time pressure of pedestrians in a fire evacuation. The distribution of pedestrians is U-shaped owing to fire avoidance behaviour and in the later stage of evacuation, pedestrians keeping away from heated walls. The trend of time pressure over time has a bimodal distribution as pedestrians initially pass the fire and the environment then becomes untenable as the fire fully develops. In addition, the exit location affects the evacuation process, with a symmetrical positioning improving the evacuation efficiency. We verify the model in a series of physical experiments. The agreement between the numerical simulation results and experimental results demonstrates that the time pressure-based model is suitable for simulating the route choice behaviour and evacuation process in fire emergencies.