Emergency evacuation speed distributions in smoke-filled tunnels

Abstract A series of experiments was performed to investigate the evacuation speed distribution in a darkened smoke-filled full-scale tunnel where participants are expected to perform urgent evacuation, the results of which provide fundamental patterns for evacuating pedestrian traffic in the event of tunnel fires. The extinction coefficient was divided into levels, namely, 0 (no smoke), I (0.01–0.5 m−1), II (0.5–1.0 m−1), and III (>1.0 m−1), the probability distribution of evacuation speeds of which were found to approximate gamma, and lognormal distributions, as reported by Seike et al. (2020) considering zero-visibility tunnel conditions. The results of the statistical analysis were used for determining the relationship between emergency evacuation speed and extinction coefficient of up to Cs = 2.2 m−1 through a set of formulations, which agree that the evacuation speed decreases with greater values of extinction coefficient. Based on the comparison between the present experimental results and that of the Swedish group, it was considered that the evacuation speed decreased rapidly at around Cs = 4 m−1, after which it approached Seike et al.’s (2020) values asymptotically.