First Responders Unprepared for Electric Vehicle Fires: Report • Hacker News Board

Re: First Responders Unprepared for Electric Vehicle Fires: Report

#21

Post by FireBeyond » Mon, Nov 23, 2020, 11:01 PM UTC

dreamcompiler wrote: post #18

Firefighter/EMT here. Our department has trained on hybrids (don't cut the big orange cable!)[0] but not electric per se. Doesn't matter. Unless there's someone in the car, we're going to stand back, let it burn, and keep it from spreading. Cars contain bigger hazards than batteries: Airbags are basically bombs, and gas lifters (the things that make the hatchback open smoothly) can become missles in a fire. And that…

> Our department has trained on hybrids (don't cut the big orange cable!)

Keep training up to date. Hybrid HV wiring has a conductive sheath around the actual wiring, separated by non conductive layers. The purpose of this is that when your tool cuts such wiring, it shorts the sheath first and trips a breaker, so that you should be able to cut.

There's a group near here (WA state) that does demos including "throwing" (dropping) battery packs into wading pools while still supplying power, and cutting HV cables on running hybrids to demonstrate this.

But then again, there's near zero reason to do so. Stabilize the vehicle, kill the 12V. Our general go-to? Put the hazard lights on. If you stop the hazards, the vehicle is "generally electrically safe".

Biggest risk that isn't often talked about? HID headlights. Picture being up against the frame of the car. Regular headlights, bulb broken, possibly? Pretty low risk. Broken headlight, and behind it is a high voltage arc? That's a very real electrocution hazard.

Re: First Responders Unprepared for Electric Vehicle Fires: Report

#22

Post by sandworm101 » Mon, Nov 23, 2020, 11:04 PM UTC

dreamcompiler wrote: post #18

Firefighter/EMT here. Our department has trained on hybrids (don't cut the big orange cable!)[0] but not electric per se. Doesn't matter. Unless there's someone in the car, we're going to stand back, let it burn, and keep it from spreading. Cars contain bigger hazards than batteries: Airbags are basically bombs, and gas lifters (the things that make the hatchback open smoothly) can become missles in a fire. And that…

Be more worried about the carbon fiber. In many ways it is like dealing with flamable aspestos.

Re: First Responders Unprepared for Electric Vehicle Fires: Report

#23

Post by gondola » Mon, Nov 23, 2020, 11:06 PM UTC

londons_explore wrote: post #5

The issue of EV batteries reigniting after a crash seems very solvable... For example, every battery cell could have a built in discharge circuit. Whenever the cell no longer received a signal from the cars computer indicating "the car is healthy" it goes into failsafe mode. Failsafe mode consists of every cell discharging to zero volts through a PTC resistor to keep a constant temperature of 150 degrees C. That will…

Li batteries ignite equally when charged or discharged. It's got nothing to do with charge state.

The ignition is caused by Li contact with air or water, when the battery barrier is breached.

Re: First Responders Unprepared for Electric Vehicle Fires: Report

#24

Post by kube-system » Mon, Nov 23, 2020, 11:08 PM UTC

mpalczewski wrote: post #16

kube-system wrote: post #3

Earlier quoted context omitted.

It's an article by a tort lawyer who is commenting on the lack of training. It is not a engineering analysis -- in context, it is clear that those chemicals were simply listed as examples.

From the article "Unique Dangers Associated with Electric Battery Fires First, during an electric vehicle fire, over 100 organic chemicals are generated, including toxic gases like carbon monoxide and hydrogen cyanide, both of which are fatal to humans." It's propaganda. "primarily to influence an audience and further an agenda" You aren't getting any facts in there that don't further the authors claims, and the ones…

Of course. I am under no impression that tort lawyers are either experts in, or interested in, chemical engineering or firefighting practices.

Their expertise is in illustrating culpability for civil wrongs.

The author is simply establishing that the situation is dangerous and has inherent differences that would necessitate different training. The actual differences in combustion byproducts are 100% irrelevant to the main point.

The author isn't highlighting the dangers of a conventional fire not because they are not dangerous, but because they are universally trained for.

Re: First Responders Unprepared for Electric Vehicle Fires: Report

#25

Post by dreamcompiler » Mon, Nov 23, 2020, 11:10 PM UTC

FireBeyond wrote: post #21

dreamcompiler wrote: post #18

Firefighter/EMT here. Our department has trained on hybrids (don't cut the big orange cable!)[0] but not electric per se. Doesn't matter. Unless there's someone in the car, we're going to stand back, let it burn, and keep it from spreading. Cars contain bigger hazards than batteries: Airbags are basically bombs, and gas lifters (the things that make the hatchback open smoothly) can become missles in a fire. And that…

> Our department has trained on hybrids (don't cut the big orange cable!) Keep training up to date. Hybrid HV wiring has a conductive sheath around the actual wiring, separated by non conductive layers. The purpose of this is that when your tool cuts such wiring, it shorts the sheath first and trips a breaker, so that you should be able to cut. There's a group near here (WA state) that does demos including "throwing"…

Holy crap! I learned a lot from this; gonna research and take it to the crew. Thanks and stay safe!

Re: First Responders Unprepared for Electric Vehicle Fires: Report

#26

Post by stickfigure » Mon, Nov 23, 2020, 11:11 PM UTC

LatteLazy wrote: post #20

exabrial wrote: post #19

One of my firefighter friends says they're a little fearful of using the jaws of life on electric vehicles since cutting through a high-voltage electrical cable would be disastrous. Luckily there are so few models right now they can memorize no-go places, but obviously this can't be counted on forever.

Edit: Cell voltage in a tesla is only 4.1V max. But there are systems with up to 375 total so I guess it's a valid question, especially as company's (not tesla AFAIK?) start putting cells into the body to squeeze as many as possible in... Original question: Isn't it all low voltage?

Maybe if you work for PG&E. The internet says Tesla packs are 350-375 volts. Definitely has the potential to ruin your day.

Re: First Responders Unprepared for Electric Vehicle Fires: Report

#27

Post by xxpor » Mon, Nov 23, 2020, 11:15 PM UTC

LatteLazy wrote: post #20

exabrial wrote: post #19

One of my firefighter friends says they're a little fearful of using the jaws of life on electric vehicles since cutting through a high-voltage electrical cable would be disastrous. Luckily there are so few models right now they can memorize no-go places, but obviously this can't be counted on forever.

Edit: Cell voltage in a tesla is only 4.1V max. But there are systems with up to 375 total so I guess it's a valid question, especially as company's (not tesla AFAIK?) start putting cells into the body to squeeze as many as possible in... Original question: Isn't it all low voltage?

Superchargers charge at 480V max, which from my understanding go directly into the cells (there's two phases in lithium battery charging, constant current and constant voltage. I'm fairly certain the constant voltage is for when the battery is low)

So technically not "high voltage" as defined by the NEC (that starts at 600V), but still plenty enough to kill you. Especially if you're wet.

Re: First Responders Unprepared for Electric Vehicle Fires: Report

#28

Post by gumby » Mon, Nov 23, 2020, 11:16 PM UTC

I’m surprised as I read when the Prius was introduced that they’d done an educational campaign specifically about this (both battery fires and how to cut the car open without electrocuting yourself). I’d assumed this was a regulatory requirement.

Re: First Responders Unprepared for Electric Vehicle Fires: Report

#29

Post by imglorp » Mon, Nov 23, 2020, 11:25 PM UTC

dreamcompiler wrote: post #18

Firefighter/EMT here. Our department has trained on hybrids (don't cut the big orange cable!)[0] but not electric per se. Doesn't matter. Unless there's someone in the car, we're going to stand back, let it burn, and keep it from spreading. Cars contain bigger hazards than batteries: Airbags are basically bombs, and gas lifters (the things that make the hatchback open smoothly) can become missles in a fire. And that…

Unscheduled airbag deployment is a terrifying concept if you're trying to lean in to access a person.

Why do military aircraft have RESCUE --> levers that disarm all the pyros but we can't make that a thing on cars? It wouldn't have to be a big red sign but it could be a standard.

Re: First Responders Unprepared for Electric Vehicle Fires: Report

#30

Post by kube-system » Mon, Nov 23, 2020, 11:28 PM UTC

bigbubba wrote: post #14

kube-system wrote: post #3

Earlier quoted context omitted.

It's an article by a tort lawyer who is commenting on the lack of training. It is not a engineering analysis -- in context, it is clear that those chemicals were simply listed as examples.

Carbon monoxide is presented as an example of a "Unique danger[s] associated with electric battery fires." Why should he get a pass for being a lawyer? That makes his ignorance more concerning, not less.

The article does not say that CO is unique to battery fires, nor does it present a comparison of combustion byproducts. The authors occupation is relevant because it can help you determine the perspective from which the article is written. A tort lawyer is interested in the culpability for a wrong. And in the case of someone being injured by chemicals, they'd want to establish that the substance was harmful. Certainly, if the byproduct of battery fires was bubblegum and gumdrops, training might not be as important. The point of the sentence you're referring to is to establish that this is not the case, and therefore, the situation merits training.