227 - The differences between EV and ICEV fires in car parks

A viral clip of an EV igniting was what started my worries about safety in car parks I have been designing. Are we ready for fast growing fires? Since 2019 I've learned and studied a lot, I've relaxed on some aspects of it and was able to identify they areas where a lot more engineering considerations should be placed. In this episode I would like to take you inside the engineering choices that shape outcomes: ceiling height, smoke control, structural details, and how fast systems wake up when seconds matter. Instead of arguing EV versus ICE, we look at what the data shows across 148 vehicle fire tests and why there’s no single “true” car fire curve.Think of a car as a set of compartments—the cabin, engine bay, trunk, wheels, and for EVs the battery pack—each with its own vents and barriers. That lens explains the wildly different heat release profiles you see in experiments and helps you separate worst-case lab setups from realistic design scenarios. We unpack why rapid battery-led growth is so challenging for low garages, how beams can trap and extend flames under the ceiling, and how wind can either help by stripping hot gases or hurt by pushing fire across bays.From there, we focus on consequences and controls. For evacuation, the goal is to avoid early smoke cut-offs and protect crowded egress moments after events. For firefighting, the single most important factor is a clear entry path—no smoke between the crew and the fire—so water can be applied fast to stop spread, even if battery cooling remains lengthy. For structure, isolated car fires shouldn’t be catastrophic in robust frames, but long, multi-vehicle burns can threaten integrity without early control.What works? Height buys time and reduces ceiling flame attachment. Smart smoke control drains energy from the layer and lowers radiation to neighboring cars. Thoughtful layouts keep chargers away from exits and closer to exhaust paths. And suppression systems may not “kill” a battery, but they cut plume temperatures, slash spread potential, and make the entire operation safer. We also surface key gaps: natural battery-initiated growth rates, context-specific risk acceptance, and handling potential explosive gas releases with low-level detection and dilution modes.If you like to learn more, see more here:Miechówka & Węgrzyński: Systematic Literature Review on Passenger Car Fire Experiments for Car Park Safety DesignZahir & César Martín-Gómez: Evaluating Fire Severity in Electric Vehicles and Internal Combustion Engine Vehicles: A Statistical Approach to Heat Release RatesCollection of Fire Science Show episodes on cars and batteriesEpisode 6 - my early research on fast fire growthEpisode 190 - Review of research on vehicle firesPodcast episode 135 - Contemplating a car park design fire----The Fire Science Show is produced by the Fire Science Media in collaboration with OFR Consultants. Thank you to the podcast sponsor for their continuous support towards our mission.