Electric vehicle warning with higher risk of explosive runaway fires

They may be environmentally sustainable, but electric vehicles pose major risks to firefighters and other first responders to road accidents.

The CFA has warned its firefighters of the “risks and dangers” of electric and hybrid vehicle fires.

ELECTRIC vehicle fires require ten times as much water to extinguish as normal petrol car fires.

The need for up to 20,000 litres to douse an electric car fire has led Australian and US fire services to issue warnings that first responders need to be well prepared when facing a fire, given the average CFA tanker holds just 3000 litres of water.

But at the same time firefighters must balance the risk of runaway thermal reactions that can occur when damaged lithium batteries tear apart water molecules, at temperatures exceeding 2700 degrees, creating an explosive mix of hydrogen and oxygen.

Electric cars are posing a high risk for firefighters.

Last year the Australian Road Research Board lodged a submission with the Federal Joint Select Committee on Road Safety, which reported US authorities were investigating a series of “significant battery fires in electric vehicles after crashes, including cases of batteries reigniting.

“Current estimates suggest that it takes on the order of 2000L of fluid to extinguish a petrol vehicle fire while it takes up to an astounding 20,000L of fluid to distinguish an electrical vehicle fire.”

US emergency services have responded to the increasing number of electric and hybrid vehicles on the nation’s roads by issuing alerts and training programs, with the US Fire Administration warning first responders “electric vehicle fires can exceed 5,000F (2760 celsius).

“Applying water or foam may cause a violent flare-up (if lithium batteries are damaged) as the water molecules separate into explosive hydrogen and oxygen gases.”

In Victoria all electric vehicles must be marked with an “EV” label on front and rear number plates.

The CFA told The Weekly Times it had communicated “the risks and dangers of stored energy technologies… to members with the distribution of safety alerts, operational bulletins and manufacturer’s emergency response guides to educate and assist emergency responders in the safe handling of electric and hybrid cars”.

“CFA is working with interstate and international partners, and industry-leading organisations to develop further guidance for CFA firefighters around battery fire incidents.”

The USFA reported the most common risks from electric vehicle fires are:

ELECTRICAL shock of up to 400 volts.

EXTREMELY high temperatures and thermal runaway.

TOXIC fumes.

LITHIUM burns (respiratory and skin reactions).

TOXIC runoff.

REIGNITION up to 24 hours after initial extinguishment.

The USFA has told its firefighters to wear breathing apparatus when attending electric vehicle fires, treat all conductive surfaces as if they are energised, until proven safe, secure a large and sustainable water supply and be aware that reignition could occur.