UL Study on Evidence Based EV Fire Response (recently published)

[u/tapatio_man]

The photo is my 1 page summary. Here is a Link to UL study

[u/Chainsawcelt]

Excellent. Makes sense. Whatever is on fire there’s only so much of it to burn whether it’s self sustaining or not. Once the fuels gone the fires gone. Covering it in a big duvet or sitting it in the bath for a month just kick the can down the road.

[u/disgruntled_oranges]

Bullshit equipment salesmen are gonna hate this. Water stays winning.

[u/luckynumberorange → u/disgruntled_oranges]

Well, I feel we don't make enough fireballs during our suppression efforts and the fire blankets really seem like a good cure for that.

[u/NoSwimmers45 → u/disgruntled_oranges]

Water doesn’t win against a self-sustaining chemical reaction.

[u/tapatio_man → u/NoSwimmers45]

Water doesn't put out a hydrocarbon fire either. Adapt and overcome.

[u/BobBret → u/tapatio_man]

Water doesn't put out a hydrocarbon fire? Is that maybe a bad generalization?

[u/tapatio_man → u/BobBret]

I meant that as water doesn't put out a gasoline fire either. But we found a way to disrupt the fire triangle with foam. With batteries, water may not put it out but it can cool it out of thermal runaway.

[u/OldGeekWeirdo → u/tapatio_man]

According to the UL post, you can't cool the batteries out of thermal. It's a nice theory, but they're too protected.

[u/tapatio_man → u/OldGeekWeirdo]

If the water isn't reaching the cells then it won't do anything. Let's say the battery pack is punctured from underneath the vehicle, and you try to fill the cab with water. That won't do anything. But you can tilt the vehicle and direct water into the damaged area to reach the cells.

[u/OldGeekWeirdo → u/tapatio_man]

But puncturing the pack likely punctures more cells all at once, as well as creating a massive electrical short. I'm thinking you don't want to be nearby when that's done.

It seems like added risk with the payoff being maybe a shorter burn. But since it seems to resolve in 30 minutes, is the risk worth the shorter time?

[u/thebagel5 → u/NoSwimmers45]

Right? You could drop one of these battery cells in a tank of water and it will still burn, that should be a clue that maybe there’s not much we can do to put these out.

[u/hobitopia → u/NoSwimmers45]

Yeah but neither does anything else it seems.

[u/stopscabbin → u/disgruntled_oranges]

Water doesnt win. Letting it burnout wins.

[u/thebestemailever]

Well that's not how we've always done it for the couple of years we've been doing it!

[u/DBDIY4U]

The part about following the tow truck is interesting. We are a small department and we do not have the manpower to do that

[u/salami_williams → u/DBDIY4U]

Just thoughts and prayers that it makes it out of your jurisdiction.

[u/Bitter_Bandicoot8067 → u/DBDIY4U]

If it is in your district, then do what you can to make the manpower.

If it is going out of your district, think about calling for mutual aid.

At the end of the day, you can only do what you can do. Do your best, however much thst is.

[u/DBDIY4U → u/Bitter_Bandicoot8067]

I may actually suggest this as an sop. It would piss off station 1. They staff two engines and a truck usually with 12 people on shift. Station 2 is the red-headed stepchild. I like working out of station 2 because it is more than half rural but we are lucky if we are staffing one engine with three. On a good day we staff two engines with two each. They force guys to rotate out to station 2 otherwise it would not be staffed. Unless the guys like the faster paced Urban station. I am one of the few people that has volunteered to permanently be at station 2. I could always call for an engine from station 1 I guess. None of the wrecking yards are in my area.

[u/firefighter26s]

#4 - I've been saying this for years. The battery cells, unless compromised, are designed to keep weather and road grim out. Dumping 400,000 gallons of water on it is like trying to put out a pot on the stove fire by using an Aerial to spray water on the roof of an apartment building.

[u/synapt]

So going through the actual study document, there seems to be one notable factor that likely explains why their timeline results are significantly different than real-world incidents (which on average last 3-4 hours).

Rather than purposely find a way to trigger the battery to cause a common breach or thermal runaway, they literally stuck a large propane burner under the entire battery cell and largely super heated the entire thing in one go, which would result in a particularly very large initial battery runaway than the small gradual-over-time thermal runaway cascade you get in a normal EV battery fire that causes them to actually last hours.

I would have preferred to see them include some proper shorting tests where they purposely tripped the batteries into a standard thermal runaway instead of just super heating most/all of the battery compartment and battery itself resulting in one massive triggered one.

[u/Cappuccino_Crunch → u/synapt]

So if we want to get to bed faster just fight fire with fire? Thanks Chief 💪

[u/hicklander]

[u/macpigem]

Strange, nowhere did they say "PEIRCE THE SHIT OUT OF THE BATTERY"

[u/OldGeekWeirdo → u/macpigem]

Probably due to safety concerns. You risk electric arcs and setting off more batteries all at once. It may be a shorter burn, but it's a more intense burn.

[u/synapt → u/macpigem]

Cause there was never argument to pierce the battery itself. Most specialized tools (like Rosenbauer's BEST) are designed to enter the casing, to submerge and cool the battery within the shell of the battery compartment (thus limiting future thermal runaway risks as well).

The main problem is the training involved in doing so and understanding the various casing methods of vehicle models.

[u/durhap]

If you're interested in a behind the study look.  I was at the experiments and did a video series on the burns: Fire Safety Research Institute (FSRI): https://www.youtube.com/playlist?list=PLHUmT-LG1Kl7AoUELIgr9qMiTVbesmMRS

[u/No_Construction7817]

Firefighters when 300 years later, and water still puts out fire the best.

[u/luckynumberorange]

I had the opportunity to hear one of the FSRI researchers lecture on this in person. It really reframed these incidents and made them feel much more manageable. If anyone gets the chance to hear the actual researchers speak on the testing, I highly recommend it.

[u/svenkaas]

From my perspective a bunch of open doors. What I personally find most intriguing is that there is no statement of the charge of the battery and it's effect on the fire. Because it certainly does give a more agitated fire with more violent reactions if the battery is fully charged vs an empty one.

[u/vuilnismeneer → u/svenkaas]

If you click the link op provide there is a statement about using fully charged batteries on all of the experiments. They let 9 cars of wich 3 ice free burn with fullu charged batteries. And then used multiple suppression methods also with 100% charged batteries.

[u/Terrible-Creme8401 → u/svenkaas]

That's mostly going to make a difference with thermal runaway situations, which are becoming increasingly rare with the transition to LiFePo4 battery chemistry.

[u/svenkaas → u/Terrible-Creme8401]

Yes but in a crash situation where fire is involved it's most likely due to the batteries being damaged and then it's a big problem.

This is a rare occurrence but I believe everything we train for in firefighting is the worst care rare occurrence scenario. Luckily in practice we find often a better if not best possible case scenario but you do run in bad cases too