Electric vehicles (EVs) are much less likely to catch fire than traditional internal combustion engine (ICE) vehicles, however, when the batteries do catch fire, the fire is much more difficult to extinguish. What does this mean for EVs parked in multistorey parking garages?
ICE car fires involve the fuel and cabin materials, which are quick to burn, and relatively easy for skilled firefighters to extinguish. Cabin-related fires also occur in EVs and can be dealt with similarly, however, the batteries are a much more significant problem because they store so much energy.
A battery fire is hard to reach because the batteries are usually located under the car. In addition, batteries can experience “thermal runaway” which is a self-sustaining chemical reaction that creates intense heat and deadly fumes, including hydrogen fluoride, as adjacent cells of the battery pack ignite. Even worse, once visible flames are gone, there remains a multi-day (or potentially multi-week) risk of reignition. The U.S National Transportation Safety Board documented one crashed EV that reignited five days after the crash, long after the fire was thought to be over. In a sense, the fire is not extinguished; it is just suppressed/cooled until the car can be moved to a safe place away from combustible materials.
The International Association of Fire Chiefs gives guidance on fighting EV fires, noting that full SCBA protection must be worn, that the fire will take significant time to extinguish and that a large volume of water (3,000 to 8,000 gallons, or roughly 11,000 to 30,000 litres) will be needed because the battery must be cooled down to ambient temperature. Where there is nothing nearby to catch fire, the guidance allows crews to stand back and let the battery burn itself out. That might work on a highway shoulder or even a driveway away from the house, but it is not an option in a parking garage, where everything within reach is an exposure: the next car, the column or slab of the garage and the residents living above. In a garage, firefighters will need to continuously apply water, often for many hours, until the battery is cool enough to safely tow the car out of the garage.
During a car fire, the sprinkler system installed in a parking garage is intended to reduce the risk of fire from spreading to adjacent vehicles, and to protect the structure from overheating. The water flow from the overhead sprinklers will not put out an EV-battery fire. The firefighters must do this using their hoses. With internal combustion engines, the one- or two-hour fire resistance rating on the adjacent columns and slabs (depending on building height) should give the firefighters enough time to deal with the fire. It is often said that EV fires burn hotter. However, tests done so far, including burns run by the National Research Council of Canada for Transport Canada, do not show that. Peak heat output from an EV was similar to or lower than the gasoline twin, because a full tank of gasoline is itself a very large fire.
What is different is the shape of the fire. A battery undergoing thermal runaway can throw a horizontal jet of flames in the next parking space. It also keeps going long after a gasoline fire would have peaked, and it can reignite as noted previously. The risk is mostly about how long the fire lasts rather than the higher temperature. It is not immediately obvious that the fire ratings for the building structural elements required by current code will be sufficient to withstand an EV fire, particularly if more than one car is involved.
Automated parking systems, which are also becoming more common, place cars closer together, and restrict access for sprinklers and firefighters, amplifying the risks.
Here in Canada, the sprinkler coverage and ventilation in parking garages have not changed since EVs have come onto the scene. The National Fire Protection Association (NFPA), whose standards are referenced in our building code, reclassified parking garages to a higher hazard group in the 2022 edition of NFPA 13, the standard which governs sprinkler systems. This raises the required water density by about a third. Two things are worth knowing about the change: it was driven by research on modern cars generally, mostly the doubling of plastics in cars since the 1970s, rather than EVs. And even the 2025 edition of NFPA 13 says nothing specific about EVs or charging stations. Either way, it will be some time until these new standards hit our building codes. For now, the Ontario Building Code still references the 2019 edition of the NFPA 13 standard. Ventilation requirements in the code are intended to deal with exhaust fumes from ICE exhausts; they are not currently designed to vent hazardous, and potentially hot fumes related to a fire.
The lag between the massive introduction of EVs and appropriate changes to codes and standards means that existing buildings, including brand new buildings, may prove to have insufficient systems in place to prevent fire spread or damage to the structure from EV fires.
According to the Zero Emission Vehicle Alliance (ZEV Alliance), governments across the globe have started implementing different safety practices. For example, in Austria, since 2023, EV-charging stations must be installed near garage entrances so that firefighters can easily remove the EV, must be protected from vehicle impact, and must be equipped with remote shutdown devices to cut power to the chargers. In the Netherlands, national guidance recommends collision protection around chargers and a single switch that cuts power to all of them at once. In the UK, the United States and Canada, research is underway to identify risks and best practices. Most current guidance and testing related to fighting EV fires currently focuses on EVs on the streets, not in underground parking garages. In other words, our building fire safety standards are playing catch up, and we are currently making it up as we go along.
A rental or commercial landlord can simply put EV parking outside or near the entrance at ground level. A condominium typically cannot, because chargers get installed in whichever owner’s particular parking spot.
What can a condominium board do right now to manage risk?
Do not let anyone interfere with the sprinklers. Make sure the garage system is being inspected and tested on the schedule the Ontario Fire Code requires, and that no heads have been painted over or blocked by stored materials.
Concierge or security staff should have written instructions that nobody silences the alarm or isolates the sprinkler system until the fire department says so, no matter how many false alarms the building has had.
When an owner applies to install a charger, the Condo Act gives the corporation 60 days to accept or propose an alternative installation as long as it’s reasonable. If your documents give you any flexibility, you should take advantage of it to cluster chargers where a fire crew can reach them: the top underground floor, close to the exit door or exhaust shaft, away from exit stairs, elevator lobbies or intake grilles for fresh air, and away from main electrical rooms.
Give the fire department one switch. A single, clearly marked labelled disconnect that cuts power to every EV charger should be provided, somewhere near the garage entrance or security desk. Otherwise, the chargers can keep feeding power to a car that is already on fire.
Update the fire safety plan and invite fire departments in. Fire safety plan should show the location of the EV spaces and chargers. Many fire departments will do a walkthrough if asked so they can become familiar with your building.
And lastly, ensure all installations are properly designed, meet code requirements, are completed by licensed electricians and that the Electrical Safety Authority has reviewed the final installation.
As the EV car stock gets larger and the cars age, we can reasonably expect that EV battery fires will become more commonplace. Codes will probably change to require additional sprinkler coverage, perhaps higher fire resistance ratings for structural elements, and possibly other features or location restrictions. Building code changes will only affect new buildings. Retrofitting of existing buildings will be governed by changes to the fire code, if any. Fire-fighting practices will also evolve, hopefully making it easier to fight EV battery fires. Our industry should watch closely as fire-fighting practices and fire code requirements catch up with the risk. And in the meantime, boards can take some of the recommended steps above.
Sally Thompson M.Sc. P.Eng,, is the Managing Principal of Synergy Partners Consulting and Past-President of CAI Canada and CCI Toronto.
Sam Soltani P.Eng. LEED AP, is the President of Trace Consulting Group and is a Director of CAI Canada.
