How dangerous is an electric car on fire?

What happens if an electric car burns in an underground car park or tunnel? Researchers at the Swiss Materials Testing and Research Institute have carried out a spectacular field test.

The Swiss Materials Testing and Research Institute (Empa) documented a field test with impressive videos. They wanted to check what particular dangers lurk and how dangerous the battery substances that are released are. What do fire brigades have to prepare for? Do tunnels, underground garages and multi-storey car parks have to be built differently with the increasing number of e-cars?

It bangs first, then a huge cloud of soot develops. And fractions of a second later, meter-high jets of flames rise up – this is what it looks like when the battery of an electric car catches fire. The Empa experts showed this in a test gallery in Hagerbach in eastern Switzerland. They filmed the fire from different angles and tested factors such as extinguishing water, ambient air and soot deposits .

Their conclusion: The fire brigades familiar with the fire of conventional cars can deal with the damage and the tunnel or underground parking garage walls and lines are not additionally endangered. “State-of-the-art tunnel ventilation can cope not only with burning gasoline cars, but also with electric cars,” says Empa. However, the extinguishing water that occurs in significantly larger quantities in electric car fires is a problem. “Chemical extinguishing water must on no account get into the sewer system”, say the Empa experts.

“The study confirms my assessment of the dangers of e-mobility, ” said Karl-Heinz Knorr, Vice President of the German Fire Brigade Association, the German Press Agency. “Electric cars burn differently, but it doesn’t matter whether a high-performance battery or 80 liters of fuel are on board. The decisive factor is the fire load.” What is meant is the material that can catch fire. Nowadays, cars have more plastic trim in the driver’s cab, plastic covers in the engine compartment, and wider tires. As a result, the fire load is two to three times as high as it was 20 or 30 years ago.

It is reassuring that the highly corrosive, toxic hydrofluoric acid that can escape from lithium-ion batteries did not reach concentrations in the critical range in any of the Empa experiments.

The more than 20,000 fire brigades in Germany would be trained to deal effectively with burning electric cars. “If we know in a fire that it is an e-mobile, we send out 5000 liters more water in fire trucks,” said Knorr. “It could be that you can’t get there with 3000 liters.” The cars have to be cooled a lot because a battery can catch fire over and over again.

The problem with the extinguishing water is actually problematic , said Knorr. The fact that this should not be allowed to go into the sewer system is more simply required than it can be implemented in practice. “When firefighters approach a burning vehicle in smoke and heat in an underground car park, for example, it is impossible to first ensure that the extinguishing water is collected,” he said.

This is no different for cars with internal combustion engines. There too, fuel, engine oil and brake fluid could leak. In an emergency, for example, at an accident site outdoors, the floor must later be cleaned or even removed.

Author: Nabeel K

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