With journalists and firefighters gathered nearby, members of the Chicago Fire Department ripped apart an already battered Chevy Volt last week. No, it wasn’t retribution for Chevrolet’s sponsorship of last season’s Green Bay Packers. It’s part of a joint effort by Chevrolet and the National Fire Protection Association, which is funded by a $4.4 million grant from the U.S. Department of Energy, to educate emergency responders about strategies for dealing with electric-vehicle crashes.
How exactly do you take a wrecked Volt apart to extricate those inside? Very carefully.
On a balcony at Chicago’s McCormick Center, where the Chicago Auto Show is held, the firefighters went to work. The Volt, a preproduction car from GM’s crash-readiness labs, was pretty banged up: Its doors were bent in, the windshield smashed and the airbags deployed to replicate a car that’s been in a serious accident.
The procedure would begin with firefighters turning off the engine, fire chief Ron Moore said. In this case, reaching through a front window and holding down the start button. Firefighters then opened the Volt’s hatch and cut the cabling to the 12-volt battery. (Virtually every car has a 12-volt; this is a standard procedure that isn’t hybrid or EV specific.) Starting at the rear doors, firefighters wedged open the frames with hydraulic spreaders – better known as the Jaws of Life – and cut the door latches and hinges to remove it entirely. The same was done on the front doors.
If occupants are pinned down, firefighters must remove the roof. This is where high-strength steel makes it tricky.
In the Volt, the window pillars have high-strength steel. “This is not mild steel of the cars in the 1980s and 1990s,” Moore said. Newer-generation hydraulic cutters are necessary. At $3,000 to $5,000 a set, EMS trainer Pete Bellows said they’re not something every firefighter has access to.
With later-generation sets, firefighters on the scene cut the Volt’s A- and B-pillars at their base, followed by cutting them at their tops. If it’s done the other way around, the pillars can warp inward onto crash victims, Bellows said. The final step was removing the roof, sliced here down the center of the car to preserve a cutaway view. The whole process of disassembly,if there hadn't been thorough explanation between each step, would have been mere minutes.
Chevy planned to display the Volt later at the convention center.
Newer cars mean new technologies, which rescue workers have to watch out for.
“We have seat belt pretensioners,” firefighter Rich Stack said. “You can’t cut into those. We have airbag prechargers and just certain things like that. You have to peel certain [interior] trim off and know where those are.”
“Potentially, it can explode like a grenade,” Bellows said of the prechargers, which deploy side curtain airbags. “You have to strip the trim and figure out where it is.”
That’s all part of the territory with any modern car. Hybrid and electric vehicles carry additional risks, marked by high-voltage cables. Any cable with more than 60 volts – the domain of EVs and hybrids – has to be orange, Bellows said. As long as firefighters exercise caution around them such vehicles pose little more risk than conventional gasoline cars.
“There’s the perception and the fear” of electrocution, Bellows said. If rescue workers know what they’re dealing with, the risk of electrocution is pretty low: “The car manufacturers, as far as I know, have done a great job” minimizing it, he said.