Prepping for EV fires
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As more EVs hit the road, one often overlooked danger is the potential fire risk from parking all those energy-packed batteries together in an enclosed space, like a garage.
Why it matters: EV fires last longer, are harder to put out and have a tendency to reignite — a major concern for underground parking garages, maintenance facilities and bus depots.
- Yet regulatory codes have lagged, leaving cities and building owners exposed to potential safety risks and costly damage.
Driving the news: Transportation agencies nationwide are transitioning to all-electric fleets.
- Yet they're not really prepared with the proper facilities to maintain them, says William Connell, senior vice president at WSP, a leading design, engineering and construction firm.
- Whether rehabbing old parking structures or designing new ones, there's very little guidance on how to prevent a worse-case scenario: hundreds of electric cars or buses going up in flames.
- "What's really caught everybody a little bit off guard in this, is that the codes and standards haven't been able to react quickly enough," Connell tells Axios.
Zoom in: WSP is behind the new South Dade Transit Operations Center under construction near Miami.
- It will be the country's first all-electric operations center, accommodating as many as 100 60-foot articulated electric buses.
- Before designing the innovative garage, WSP engineers had to assess the depot's unique fire risk, borrowing expertise from fire suppression techniques in tunnels.
- That meant adding advanced water sprinkler systems and fireproof coatings to the structure, as well as ventilation and fire detection improvements.
Reality check: EV fires are rare.
- Some experts say they occur less frequently than fires in cars with traditional internal combustion engines, although more research is needed.
- Most vehicle fires occur on the road, but those in parking garages can cause huge economic losses — damaging structures and destroying hundreds of vehicles, in some cases.
- The danger extends to cargo ships packed with EVs, too: One vessel carrying more than 3,000 cars caught fire and sank in 2022 after an EV battery malfunctioned aboard.
How it works: "Thermal runaway" is the scary-sounding euphemism for what happens in an EV fire: one battery cell short-circuits, and the resulting fire spreads uncontrollably to others.
- A single cell inside an EV's lithium-ion battery can be damaged in a crash, or even by spikes of lithium called dentrites that build up inside the battery over time.
- The abused cell releases heat and flammable chemicals, affecting other cells. The hotter the battery gets, the more energy is released — creating a self-sustaining fire.
- The resulting chemical reactions allow EV fires to reignite hours or even days after they appear to have been extinguished.
Plus, modern vehicles have a lot more plastic — nearly 10% of their overall weight today vs. less than 3% in the 1970s — increasing their flammability.
- New parking garages are now required to have automatic sprinkler systems, but EV fires require at least twice as much water to douse, which means water supplies could be an issue.
The bottom line: The best solution, says Connell, is often to smother a burning EV with a suppression blanket, tow it from the garage and watch it burn.
