HN Theater @HNTheaterMonth

⬐ jcpham

FWIW as a volunteer first responder, magnesium fires (that's what the dash is made from these days in most of your vehicles, electric or non) are extremely dangerous to spray water on. It goes boom, it shoots sparks, it's frightening to witness.

I'd recommend a dry fire extinguisher or potentially a foaming agent, but the last thing you want to do if you value your life is send burning white hot magnesium embers flying with a high pressure water hose.

Tesla's mileage must vary obviously or they've never sprayed water on a magnesium fire.

⬐ serg_chernata

The cars were given a really high safety rating. That makes me assume that the speed and severity of this collision far exceeded those used in testing. If that's the case, nothing can save your life in that situation.

⬐ shawn-butler

I think the point of the story is that the response is delayed by the increased complexity of containing a fire in an ev-crash compared to that of a ice-crash.

Tesla maintains training guides for first responders: https://www.tesla.com/firstresponders

⬐ joezydeco

Those are some nice guides.

The Model S one also shows you how to completely disable someone else's car while it's locked. Interesting.

⬐ 6stringmerc

Yeah I look at it more as a learning opportunity. Nothing inherently wrong with something having a catastrophic failure by way of user error, I mean, speaking from a safety expectations standpoint.

I think helping more departments get educated on protocols will continue to benefit EV adoption. Not just Tesla.

⬐ bArray

Could replace the batteries with fuel and we'd have the same story, I've seen some horrific car fires from conventional combustion engines.

You're always driving around with a lot of energy - when it all gets released at once people die.

⬐ admax88q

> I've seen some horrific car fires from conventional combustion engines.

Yay anecdotes! The real question is whether or not battery fires are harder to put out than gasoline fires.

The current recommended practice for a lithium ion battery fire is to let the fire burn itself out...

⬐ bArray

>Yay anecdotes!

I'm not claiming superior knowledge, just sharing my experience. Experience is valuable too. If you have facts the show something alternative, bring them to the conversation.

I have involvement with an automotive business that buys cars that have been written off. In short, I see a lot of cars and how they failed.

>The real question is whether or not battery fires are harder to put out than gasoline fires.

>The current recommended practice for a lithium ion battery fire is to let the fire burn itself out...

Good point. Actually, I think better pre-crash measures need to be taken. If a battery is about to explode, I imagine it be possible to control where that explosion happens, i.e. directed away from the cockpit.

⬐ Declanomous

That's all well and good if the fire takes place on a normal road, but that seems extremely dangerous if the fire takes place in a tunnel or on/under a bridge. Are we going to need autonomous vehicles to drag burning cars out of tunnels so they don't cause structural damage?

Not trying to knock electric cars, I'm a huge proponent of them, I just am not a fan of hand-waving about safety. Vehicles are probably the most destructive thing most people own. You can literally cause tens of millions of dollars in damage with a car merely through negligence. Pretty hard to do that with anything else normal people have access to.

⬐ bArray

>Are we going to need autonomous vehicles to drag burning cars out of tunnels so they don't cause structural damage?

Even then, I imagine a lot of damage being done extremely quickly. I think the way forward is with damage limitation when crashes eventually happen.

>Vehicles are probably the most destructive thing most people own. You can literally cause tens of millions of dollars in damage with a car merely through negligence. Pretty hard to do that with anything else normal people have access to.

Ever seen an old person forget they left the gas cooker on? But sure, with great power comes great responsibility. I can see automotive law becoming stricter as a result given the damage that can be done.

⬐ michaelgrafl

Can a firefighter explain to me how this crash would have been different if it had happened in a Maserati? Because otherwise there is no story here, except that weird, horrible accidents now happen with electric cars, too.

⬐ JoeAltmaier

Isn't it because LiOn batteries have their oxidizer in them? So its like jet fuel or something - fuel and liquid oxygen mixed can't be 'put out'. Neither can battery fires. They have to burn to exhaustion.

⬐ Retric

You can just use water to extinguish LiOn fires. http://batteryuniversity.com/learn/article/safety_concerns_w...

"Lithium-ion batteries contain little lithium metal and in case of a fire they can be dowsed with water. Only lithium-metal batteries require a Class D fire extinguisher."

⬐ JoeAltmaier

Firefighters say in no uncertain terms that water should never be used. Also this site claims only foam extinguishers should be used:

http://venturaaerospace.com/news/suppressing-lithium-ion-bat...

⬐ moogly

There was an article about a Tesla fire at a Supercharger station in Norway a year back, and the firefighters back then said you were supposed to use water with some form of copper in it, and that it was too costly to use now, so they let the car burn.

⬐ bmh_ca

From Tessla's first-responder guide:

> If the high voltage battery catches fire, is exposed to high heat, or is bent, twisted, cracked, or breached in any way, use large amounts of water to cool the battery. DO NOT extinguish with a small amount of water. Always establish or request an additional water supply.

⬐ JoeAltmaier

'large amounts' is probably an effort to cool the rest of the pack and prevent the fire spreading. Not a way to actually put out the cells already on fire?

⬐ Retric

Remove enough heat and fires stop. The geometry of battery packs may make this difficult, but at a minimum it can prevent secondary fires.

PS: However, simply letting a wretched car burn is generally safe and the car is already totaled so there is little reason to mess with it.

⬐ dwighttk

wouldn't have to put out fires fueled (apparently) by magnesium

⬐ johnward

They put out gasoline and diesel fires. Is it because they are not yet prepared to deal with battery fires? I feel like all vehicle fuels are volatile in an accident, including batteries.

⬐ manganese

Magnesium.

But, yes, operator error, unless auto-pilot is found to be involved.

⬐ dogma1138

Isn't auto pilot speed limited?

It from the witness reports and the wreck it looks like they were traveling at considerably higher speeds than the limit.

⬐ brentm

It's a local news story posted to HN at this point. Local news always covers these type of events, especially with theatrics like a fireball caught on video. It doesn't seem like something that would become national news based on that report.

⬐ jstx

Seems strange that there is no mention of the purported significance of the passengers. Were they never confirmed?

http://www.theindychannel.com/news/local-news/2-killed-in-fi...

⬐ dogma1138

Heh...

>Another important difference between batteries and gas is that emergency workers (and anyone who's involved in the accident) can identify when the gas is leaking out, it's also much easier to stop the gas from catching on fire as wetting the vehicle or using other fire retardants will usually prevent the gas from catching fire. On the other hand you can have an internally shorted battery pack which can catch fire or explode at any moment and you would have no clue that it can happen.

https://news.ycombinator.com/item?id=11874737