Study on Occurrence Factors and Propagation Conditions of Congestion in Staircases during Phased Evacuation Drill in a High-rise Office Building

Abstract

When a large-scale fire or a serious emergency occurs in a high-rise building, it is highly likely that all occupants start to evacuate at once, which might generate risks of congestion and overcrowded status in staircase. However, due to insufficient investigation data acquired from actual total evacuations from high-rise buildings, the entire picture of the mechanism that causes and finally ends up with congestion in a staircase has not yet been studied. In this study, we analyzed the results of recording the behavior of approximate 800 evacuees on stair landings using video cameras during a phased evacuation drill conducted in a 25-story high-rise office building. We discussed causes, propagations and eliminations of congestion after merging in the staircase. As a result, the three occurrence factors of congestion and the threshold densities at landings and stairs causing congestion propagation has been clarified.