Fire simulation analysis of pure electric buses incorporating flame-retardant vinyl ester composites

Pure electric buses are widely used due to their environmental protection and energy-saving features, but frequent fire accidents exist. This paper made a comparative analysis of the combustion process of pure electric buses with two kinds of seats, which were fabricated from vinyl ester resin materials with and without flame retardant 6,6'-(1-phenylethane-1,2 diyl) bis (dibenzo[c,e][1,2]oxaphosphinine 6-oxide) (PBDOO). Analysis was conducted on the heat release rate, compartment temperature, carbon monoxide and carbon dioxide composition, and smoke propagation during the combustion process of the bus. Under the established working conditions, the fire on the rear side of the pure electric bus first increases rapidly, then grows slowly after 600s, and finally enters stable combustion at 900s. Incorporating PBDOO into the vinyl ester resin composite significantly lowers the pure electric bus's heat release rate (HRR). The bus with flame-retardant seat materials exhibited slower increase rates of CO and CO2 concentration in the early stage, and the CO concentration was significantly lower than that of the bus with no modified VE material between 300 and 600s. The simulation results show the practical application effect of flame-retardant VE materials, which is helpful for further research on fire rescue of pure electric buses.