Covered and underground car parks were already demanding fire environments. Add high-capacity EV charging and the hazard profile changes again: thermal runaway, re-ignition, smoke, and longer cooling times than a conventional vehicle fire.
The response is a layered strategy, not a single product. Detection, ventilation, suppression, structural assumptions, fire-service access, and operating procedures all belong in the same review. Our article on fire suppression for underground car parks and EV charging hubs sets out why.
Where sprinklers help, and where they do not
Traditional sprinklers still have a role in protecting the building. They can slow spread to neighbouring vehicles and protect the structure. They are usually not enough on their own to stop a battery fire inside the pack, especially in a congested or enclosed charging bay. Removing the sprinklers is not the conclusion. The car-park strategy needs more than the sprinkler layout.
Water mist, deluge, or other localised cooling may be appropriate in some layouts, where the geometry and the design evidence support it. Mist is not a guarantee that a module fire inside a lithium-ion pack will be extinguished. None of those options is a universal EV solution.
Landlords and fleet operators also face an insurance conversation. Insurance, compliance, and EV fires covers the evidence that reviewing parties typically ask for.
Thermal runaway, in practical terms
Thermal runaway is a self-sustaining reaction inside a lithium-ion cell. Damage, an internal defect, overcharging, or prolonged heat can start it. The pack can then vent flammable gas, produce heavy smoke, and reignite after the first flames look controlled. The incident often lasts longer than a conventional vehicle fire and needs cooling, smoke management, and a plan for watching the vehicle after the first attack.
That changes water supply and drainage as well as the nozzle layout. A system sized only for a short vehicle fire can run short if cooling has to continue. Contaminated runoff needs somewhere to go. Those are design inputs, not notes added after the chargers are on the wall.
Guidance in England, and elsewhere in the UK
In England, the Office for Zero Emission Vehicles published interim guidance on covered car parks and electric vehicles. It is non-statutory. It asks designers and operators to consider detection, suppression, ventilation, structural fire resistance, vehicle spacing, water supplies, and runoff, then write down the choices. It is not a finished national code, and it does not automatically apply in Scotland, Wales, or Northern Ireland.
Approved Document B remains the Building Regulations fire-safety guidance for relevant building work in England. It does not replace a site-specific fire risk assessment under the Regulatory Reform (Fire Safety) Order 2005.
What we need to design
Drawings, charging specification, whether the deck is underground, ventilation strategy, and any insurer or fire-authority comments. From that we can say whether mist, sprinklers, detection upgrades, or a hybrid approach is even in play.
Contact our engineers before charging infrastructure is treated as a services extra on a generic car-park fire strategy.
