Simulation study on the effect of pre-evacuation time and exit width on evacuation

摘要

Occupant pre-evacuation time is often oversimplified into an explicit value in evacuation calculation. In fact, it is not an explicit value but a random variable following some kind of probability distribution. In order to analyze the importance of pre-evacuation time in evacuation calculation, Grid-Flow evacuation model is utilized to study the effect of pre-evacuation time on evacuation under different occupant densities and exit widths in a single room scenario. The evacuation time calculated by using normal pre-evacuation distribution is compared with that calculated by explicit pre-evacuation time. Two faults are presented when pre-evacuation time is considered as an explicit value. The theory of congestion and queue is presented to analyze the calculation results. Moreover, this paper also presents probability distribution of the total evacuation time when the pre-evacuation time follows normal distribution. The results show that the evacuation time is dominated by pre-evacuation time and hardly dependent on occupant density when the mean pre-evacuation time is long. For long mean pre-evacuation time, low occupant density or wide exit, when pre-evacuation time follows normal distribution, the total evacuation time also follows normal distribution.