Numerical analysis of the impact of electric bicycle fire on the occupant evacuation in old residential building

Due to the characteristics of environmental protection, energy saving, low cost and small size, electric bicycles are the most popular means of transportation in China. In recent years, several fatal electric bicycle fires have occurred, causing numerous casualties in old residential buildings. This paper uses numerical assessment tools to examine the impact of electric bicycle fires on occupants' safety and evacuation in a typical old residential building. However, traditional numerical methods for simulating fire evacuation do not consider the impact of fire products on occupants, leading to inaccurate evacuation simulation results. In this research, the evacuation simulation is combined with CFD results to reflect the effect of electric bicycle fire products on occupants' evacuation progress. The results show that an evacuation model considering the impact of fire products better reflects the real smoke's effect on evacuation progress than traditional numerical simulation. Specifically, reduced visibility significantly increases evacuation time, and toxic and irritant gases significantly increase the FED values of occupants. Furthermore, during rapid fire development, occupants should use the top-floor room as a refuge, closing doors and windows to prevent toxic gas entry, instead of escaping downward.