Fire Safety Analysis of Alternative Vehicles in Confined Spaces: A Study of Underground Parking Facilities

This study investigates the fire behaviour of Battery Electric Vehicles (BEVs) and Internal Combustion Engine Vehicles (ICEVs) in confined environments such as underground parking facilities and tunnels. Using the Fire Dynamics Simulator (FDS), several scenarios were modelled to analyse the effects of ventilation and automatic suppression systems on fire growth, heat release, and smoke propagation. Three ventilation configurations—reduced, standard, and increased airflow—were evaluated to determine their influence on combustion dynamics and thermal development. Results show that BEV fires produce higher peak Heat Release Rates (up to 7 MW) and longer combustion durations than ICEVs, mainly due to self-sustained battery reactions. Increased ventilation enhances smoke removal but intensifies flames and radiant heat transfer, while limited airflow restricts combustion yet leads to hazardous smoke accumulation. The inclusion of a sprinkler system effectively reduced temperatures by over 60% within 100 s of activation, though residual heat in BEVs poses a risk of re-ignition. This underlines the need for tailored ventilation and suppression strategies in modern underground facilities to ensure safety in the transition toward electric mobility.