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## Tesla Fires and Firestorms: Let's Breathe and Review Some Car Fire Math264

cartechboy writes "There are about 150,000 vehicle fires reported every year in the U.S. — about 17 every hour, on average. But when that vehicle fire is a Tesla, the Internet notices. There have now been three fires among roughly 20,000 Tesla Model S electric cars on the road so far. The stock is down, the Feds are asking questions and the Internet is swimming in Tesla news. It may be time to check the facts and review some math (hint: we're looking at roughly one fire for every 33 million miles driven so far) and then breathe. Then look at what we know, what we don't know, and what we should know."
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## Tesla Fires and Firestorms: Let's Breathe and Review Some Car Fire Math

• #### How about just battery fires also? (Score:4, Insightful)

on Friday November 08, 2013 @07:51PM (#45373671)
It is not useful to simply compare the rate of vehicle fires. That is important, but it is only half of the question.

What would be useful would be to also compare the rate of non-Tesla car fires originating from the battery, with that of Teslas.

It would not be advantageous for Teslas to have 'essentially eliminated" the risk of fuel fires, if doing so also include drastically increasing the risk of battery fires.
• #### Re:How about just battery fires also? (Score:5, Insightful)

by Anonymous Coward on Friday November 08, 2013 @08:25PM (#45373933)

[Assuming that fuel fires and battery fires are equally weighted as far as severity goes, which is obviously some frictionless-perfect-sphere-style handwaving...]

Let's say with gasoline-powered cars, the risk of fuel fire is 1%, and the risk of battery fire is 0.01%. The odds of your car igniting is 1.01%.

And let's say Tesla has effectively eliminated fuel fires, but it's now 50 times more likely that your battery start a fire. That's a 0.50% possibility of your car igniting.

All other things being equal, I'll take the car that is half as likely to catch on fire.

(Yes, the numbers are all made up, but the point is, I don't care WHAT lights my car on fire; I only care how likely it is that my car will light on fire. Therefore, I think it makes sense to look at all vehicle fires.)

• #### Re:How about just battery fires also? (Score:5, Insightful)

on Friday November 08, 2013 @08:56PM (#45374169) Journal

I don't care WHAT lights my car on fire; I only care how likely it is that my car will light on fire.

Hang on a second. You make it sound like gasoline or batteries set your car on fire, and then your "car" is simply burning. You do realize the gasoline is 99% of what is burning, and not really the "car" itself, right? So there's more to it than the cause or frequency, but the nature of the fire itself. Gasoline is particularly bad because it is a liquid that typically flows all over and around the scene of an accident, then it is the evaporated vapor of the fuel that combusts openly in the air. Essentially, it will spread and consume the entire car and surrounding area because of its liquid nature. Lithium batteries burn in an entirely different manner. It seems likely to me that a Tesla battery fire would be much more contained and thus less dangerous than a gasoline fire.

Your logic is like saying that headaches and strokes are equivalent medical events involving the brain, and you'd rather have strokes since they occur less often. I don't think most people would share that kind of opinion.

• #### Re: How about just battery fires also? (Score:4, Informative)

on Friday November 08, 2013 @09:40PM (#45374433)

That's discounting other sources of iginition. Fuel fires are not the primary cause of car fires.

Catalytic converters, voltage regulators, and alternators also play significant roles. Devices used to generate and manage variable electrical loads cause more fires.

• #### Re: (Score:3)

True, but so far (the numbers are small, so don't extrapolate too literally) EV fires appear to be contained and not kill people, while gas vehicle fires destroy entire vehicles and fairly often kill people.

• #### Re: (Score:2)

Not only that, but I'd take the fire overall being "you're pretty much out of a car now" regardless as to what causes it, so a lower percentage overall is what really matters. Once you combine that with the battery fire being slower to progress towards a person who needs to get out ASAP, it's clear the Tesla can be a winner if the data comes out statistically showing that this is true over time.
• #### Re: (Score:3)

You do realize the gasoline is 99% of what is burning, and not really the "car" itself, right?

No, that's not necessarily true. my parents' garage burned down a couple years ago and totally destroyed a car inside - but the gas tank survived. The car was a shell, every bit burned down to the metal frame, except for the gasoline in the tank. Gas tanks have had 100 years of engineering to help prevent fires. Lithium batteries in cars are a completely new issue, and are going to have their growing pains.

Personally I agree with the point that there is not enough data to support Lion battery cars are a

• #### Re: (Score:2)

Factor in the survivability of the fires as well. Gasoline fires tend to escalate rather quickly.

• #### Re:How about just battery fires also? (Score:5, Informative)

on Friday November 08, 2013 @08:40PM (#45374047)

Remove your biases for a moment and read TFA. All this bullshit doom and gloom is nonsense propaganda, or at least most of it. Most likely, brought to you by several groups of people that don't benefit (enough) from EVs, and stand to lose a whole lot of money if they begin to be successful.

Accident 1. It apparently occurred after the Model S ran over a piece of road debris later described as a "curved section that fell off a semi-trailer." That item punched a 3-inch hole through the 1/4-inch-thick armor plate protecting the pack, with a force of 25 tons, according to a report by Tesla. The car alerted the driver of a fault, and he pulled over and exited the car.

Emphasis is mine. It should not take a rocket scientist to guess that this is a big fucking piece of steel. It may not have made your Combustion car catch fire, but your car would have most taken tremendous damage at least. Your car does not have 1/4-inch armor plating, so you may not have lived through it.

Accident 2. It apparently occurred after the Model S driver jumped a curb, took out several feet of a concrete wall, and then hit a tree.

Ever hear of Michael Hastings who died in a new Mercedes that hit a tree and caught fire? It happened very recently, so you can save the "it never happens with gas cars" lines. I don't think the mention of the guy being drunk makes a lick of difference to the point. The point is, this guy was driving very fast and crashed into a bunch of hard stuff.

Accident 3. It too apparently occurred after the Model S ran over a piece of road debris, this time reportedly described by police as a tow hitch that pierced the undercarriage. Tesla issued this statement: “We have been in contact with the driver, who was not injured and believes the car saved his life. Our team is on its way to Tennessee to learn more about what happened in the accident.”

So once again, we have a massive piece of road debris that would have totaled any other car on the road as the culprit, and as of yet an unknown cause of fire. Note the drivers opinion that the car saved his life and received no injuries. Sure, he's not an expert but you were not there so are not an expert either.

All this shit keeps pointing to some people wanting bad press for EVs because, you know.. we kill a whole lot of people to get this oil that should be able to transfer a good chunk of your money to them!

• #### Re: (Score:2)

The problem isn't whether the car would of or would not have taken damage. The problem is that a fire is capable of spreading and causing serious other problems outside of the car. Suppose the damage happened but the fire didn't until the car was parked inside your garage that is connected to your home.

But more appropriately, the solution to the fires may be found in the investigations of the situation where something simple like an automatic resetting breaker between battery banks could contain the damage

• #### Re: (Score:3)

The problem isn't whether the car would of or would not have taken damage. The problem is that a fire is capable of spreading and causing serious other problems outside of the car. Suppose the damage happened but the fire didn't until the car was parked inside your garage that is connected to your home.

This is actually a really good point. With a gas car if you have a gas leak you can smell it. If you go to park your car in the garage and your gas tank is leaking you will smell it and move the car outside of the garage pretty quickly. However, a battery pack that is damaged could be slowly heating up and you would never know until it exploded or caught fire.

I don't know how Tesla implemented the battery packs in their cars. I would hope that they would have implemented smart batteries that would warn

• #### Re: (Score:3)

The only valid "what if" is comparing the incidents to a combustion car, because that's what the hype is about. You can't claim "what if the car caught fire in the garage hours later" because that hypothetical NEVER HAPPENED!

The only reason to bitch about the fire is to present the concept that Tesla does not care about the fires and will never fix them. That, is idiocy! Stop and look at everything in comparison and context with other vehicles.

Example 2 is very clear, crashing into trees will cause combu

• #### Re: (Score:2)

What would be useful would be to also compare the rate of non-Tesla car fires originating from the battery, with that of Teslas.

How in the hell would that be useful, when the Tesla batteries are the Tesla "fuel source"??? Think about it, that comparison would make absolutely no sense at all!

• #### Re: (Score:2)

It is more complicated then that. The comparison needs to involve details such as age of the vehicle and modifications/repair work done to it. Most vehicles that are new (within a few years) will not catch fire in accidents in which the occupants are not seriously injured. Most vehicle fires in cars not involved in serious crashes that I am aware of are generally the result if improperly performed maintenance, neglected repairs, or modifications and typically happen to cars that are aged.

If new cars, unmodi

• #### OK, here is some math. (Score:5, Informative)

on Friday November 08, 2013 @07:51PM (#45373679) Journal

According to the US Bureau of Transportation,there are over 250 million cars on the road in the US. There are 150,000 fires in those vehicles a year __according to the OP__.

There are 20,000 Tesla cars, with 3 fires.

Relative risk = ( 3 / 20000 ) / ( 150000 / 250000000 ) = 0.00015 / 0.0006 = 0.25.

Get a Tesla, so as to avoid vehicle fires. Maybe? Depends on whether the reported stats are correct.

• #### Re:OK, here is some math. (Score:5, Insightful)

by Anonymous Coward on Friday November 08, 2013 @08:01PM (#45373747)

Generally conventional cars burn when they are old. Calculate how many cars up to one year old are burning in comparison to Tesla.

• #### Re:OK, here is some math. (Score:4, Insightful)

on Friday November 08, 2013 @08:19PM (#45373861)
This. Older fuel hoses crack and split, older cars may have received little/no routine maintenance other than enough to keep them running, etc.

OTOH, you could also limit the comparison to cars costing twice the average price of cars when new - those might be expected to receive better maintenance.
• #### Re:OK, here is some math. (Score:4, Insightful)

on Friday November 08, 2013 @09:00PM (#45374197)

Exactly. With a straight face, they cite statistics comparing a new \$100,000 Tesla with an old beater that is held together with duct tape and probably worth a few hundred bucks.

• #### Re: (Score:2)

Exactly. With a straight face, they cite statistics comparing a new \$100,000 Tesla with an old beater that is held together with duct tape and probably worth a few hundred bucks.

But the risk of battery puncture and fire doesn't get worse as the Tesla ages, so a 10 year old Tesla shouldn't have any different fire risk than a brand new Tesla, so it doesn't seem unfair to compare across all cars.

• #### Re: (Score:2)

But the risk of battery puncture and fire doesn't get worse as the Tesla ages

Why do you think so? LI-Ion batteries experience significant mechanical deformation as they are charged/discharged. There is a lot of vibration that is transferred into the battery from the road. Old batteries require longer charging, at higher temperatures. The numbers will not be the same.

There is yet another issue. Batteries are essentially strips of plastic tape that have goo smeared onto them, and then the strips are roll

• #### Re: (Score:3)

But the risk of battery puncture and fire doesn't get worse as the Tesla ages

Why do you think so? LI-Ion batteries experience significant mechanical deformation as they are charged/discharged. There is a lot of vibration that is transferred into the battery from the road. Old batteries require longer charging, at higher temperatures. The numbers will not be the same.

There is yet another issue. Batteries are essentially strips of plastic tape that have goo smeared onto them, and then the strips are rolled up to form an element. There is not much accuracy in this process, and not much repeatability. Some batteries may serve longer than expected, and some may fail prematurely. Some failures can cause fires. A gas tank is a precision instrument, compared to a battery. It can be inspected for leaks, but a battery cannot be inspected in a similar way - there are too many sealed elements, and each of them is manufactured by the lowest bidder. We haven't seen yet battery fires in Teslas that are caused by an intact battery. But as more cars are put onto the road, and as they accumulate more miles, this may become an issue.

Sure, it's possible that a completely different failure mode will cause fires, but that can't be extrapolated from fires caused by punctures.

• #### Re: (Score:2)

True the risk is still relatively low per mile driven. Might be more than typical for gas powered cars though of similar price/age. Just a guess why: a lot of car fires are caused by electrical problems given bigger electrical currents an electric car would be more likely to arc and have sufficient current in an arc to start a fire. That said there probably were more accidents getting into and out of gas stations for the equivalent road miles driven than either electric or gas cars have fires.

• #### Re: (Score:2)

When they crash into trees? Michael Hastings, enough said because his Mercedes was not old. When they have massive steel debris punched into them? Okay pally, you keep right on shilling.
• #### On the other hand... (Score:3)

On the other hand, ICEs and their gasoline tanks have been through much more real-world testing, many more iterations of safety refinement based on real world experience. Perhaps a more fair comparison is to look back to the 1920s and see how often new luxury cars from that era experienced fires.

Tesla is obviously aware of this problem and has a strong incentive to make their packs robust. Gas tanks in race cars have things like rubber bladders, honeycombs, and perhaps other things I've never heard of. I

• #### Re: (Score:2)

Better per mile driven, and taking into account relative driving styles, maintenance efforts, car ages, etc.

There's really not enough data to say that these electric cars are safer, merely a lack of data to confirm that they're either significantly less or significantly more safe, comparing like for like.

I think Musk is the worst sort of businessperson, from useless money-sink Paypal to sucking off the government space programme teat. But I wouldn't mind Tesla cars approaching the mainstream automobile mark

• #### Re: (Score:2)

You'd have to compare all the models, not just Tesla compared to the average of all other cars. If one brand of cars happen to catch fires all the time, Tesla could be the second worst and still come out better than average.

• #### Probably going to clear Tesla (Score:5, Interesting)

on Friday November 08, 2013 @07:53PM (#45373689) Homepage

In all 3 cases, it seems like the fire was caused by severe damage to the car from an outside source rather than a fault in the car. In all 3 cases the car's design prevented injury to the driver from the fire rather than contributing to the fire. And, let's face it, if we investigated every conventional model of car that was involved in 3 fires in a single month, every single model would be under investigation continuously. So, the people panicking over this and getting rid of Tesla stock, and the people pointing to this to impugn Tesla, need to get a grip. There's other reasons not to like Tesla, but it's not because their cars are in any way unsafe (or at least nomore unsafe than ~2 tons of steel barreling along at between 80 and 110 feet per second carrying between 10 and 30 gallons of highly flammable fuel (which forms explosive vapors under normal environmental conditions) in a thin sheet-metal tank with no armor or other protection against penetration).

• #### Re: (Score:2)

Gasoline and electric cars catch fire for different reasons. In two of the cases of Tesla fires the damage was from road debris hitting the car from below (possibly lifted by the tires?). This is relatively frequent event on the road, so there is a good reason at the very east to look at the details of the incidents and consider the possibility of adding a new safety test for electric vehicles. Gasoline cars typically shrug off hits to the undercarriage, because while they have fuel and break lines running
• #### Re: (Score:3)

..and the people pointing to this to impugn Tesla, need to get a grip.

Nah, I suspect those people have a very firm grip on the facts and know exactly what they are doing!

• #### Tesla fire is good news (Score:5, Insightful)

on Friday November 08, 2013 @08:02PM (#45373753)
I was looking to purchase some TSLA, here is my opportunity.

• #### dropped cigarettes, intentional etc. vs. spontaneo (Score:3, Informative)

on Friday November 08, 2013 @08:03PM (#45373767) Journal

The "all car fires" stat includes dropped cigarettes that smolder, cars intentionally set on fire, etc.
How many regular cars light on fire on the highway after running over a debris such as a hitch?

Also, how many do you want to have on fire? How many would ignite if there was a shield that would flex rather than puncture?

• #### Re: (Score:2)

How many would ignite if there was a shield that would flex rather than puncture?

Flex where? If it's up against the battery, when it flexes it will compress the cells, causing exactly the kind of damage that causes fires...

• #### not my department, but I visit that department (Score:2)

>. Flex where? If it's up against the battery, when it flexes it will compress the cells, causing exactly the kind of damage that causes fires...

Intuitively, you'd think to make a car safer, you'd make it stronger. In fact, you reduce G forces by designing it to crush - crumple zones. How can the shielding or battery positioning be improved? I don't know, but I hope Tesla's engineers are asking those questions.

At Texas Transportation Institute (part of the agency I work for) they're still crash testin

• #### Re: (Score:2)

The "all car fires" stat includes dropped cigarettes that smolder, cars intentionally set on fire, etc.

Exactly.

How many regular cars light on fire on the highway after running over a debris such as a hitch?

NFPA report [nfpa.org]. Same source as the other stats cited in the article, not mentionning the causes was a simple oversight, right ? I didn't check the full PDF reports yet.

So, three fires for Tesla vehicles, one of them caused by "collision or overturn", and the two other by... malfunction ?
There is also bias as "older vehicles were more likely to have a fire caused by mechanical or electrical failures.".
I'm surprised arson counts for "only" 8 percent of reported fires.

Anyway, Musk and the writer's stats

• #### Re: (Score:2)

the two other by... malfunction ?

Striking something hard enough to punch through a 1/4" steel plate is not called a "malfunction", it's called a car accident.

• #### Re: (Score:2)

The "all car fires" stat would then also include Tesla cars in the cases where fires were due to cigarettes or intentionally. Even disrgarding that considering Teslas alone having burned vs these stats is unfair to Tesla cars; They still come out on top. I had a car fire after just parking it on the side of the road in autum -- there were leaves. I checked, and my gassoline tank is still on the bottom of my car, so what is your point about the debris bit, mate? Are you trying to leverage confirmation b

• #### huh? No idea, but you're horny for Tesla? (Score:2)

I'm not sure what you're trying to say there.
I asked a couple of questions:
How many gas cars light on fire as opposed to being lit on fire?
How can electric cars be made safer?

It's not clear what you're trying to say, so tell me if I have this right:

You have no idea what the answer is to either question, but "Tesla comes out on top". Why? Because Tesla man! Fuck yeah Tesla motherfucker! Tesla kicks ass man!

Do I have that about right?

• #### Re: (Score:2)

I've personally frantically tried to waive down an interstate driver that had 10' flames running along the bottom of his car (he had no idea he was on fire because gas fires in the early stage are nearly smokeless). That driver barely survived, the car was almost fully engulfed before he could even stop. IIRC he has first degree burns to his legs. The car was a smouldering ember that was 95% burned out before the fire department even got there.

If you haven't seen a gas car burn you are either ignorant of wh

• #### only on Slashdot (Score:2)

I asked how many cars get lit on fire (arson, smoldering cigarettes, etc.) versus how many light themselves on fire.

You think I claimed cars can't burn. Only on Slashdot.

• #### The oil lobby (Score:4, Insightful)

on Friday November 08, 2013 @08:08PM (#45373797) Homepage

It is no surprise that the oil lobby is jumping on this. Even when in reality it is more dangerous to be in a car that runs on oil or gasoline than lion batteries. While batteries are not risk free, they are considerable lower risk than using oil and gasoline cars.

• #### Re: (Score:2)

I would not be shocked at all to think that Tesla has so many enemies that the very lives of the owners and managers of the company are at risk of murder. Big industries do not like to fail and Tesla has such a superior product that there is almost no reason to buy any other brand. Not only are the Detroit based companies upset but the gas and oil industries don't love Tesla one little bit. Then to top it off there are tons of dealers that hate Tesla and on top of that conventional garages and mec

• #### Re: (Score:3)

It is no surprise that the oil lobby is jumping on this

What evidence do we have that the oil lobby is jumping on this?

• #### Ancient safety engineering principles (Score:5, Insightful)

on Friday November 08, 2013 @08:12PM (#45373827) Homepage Journal

1. Stored energy is a hazard
2. Humans are fragile
3. Therefore create barriers between humans and stored energy.

Any self-powered vehicle with useful range needs a lot of stored energy. This can be in a form that drips and pours out of any opening in can find, like gasoline, or it can be chemical energy in a solid battery.

Tesla engineers implemented point 3 so well that the guy in Auburn opened the door and walked away from the uncontrolled release of energy happening in front of him.

Complete non-story, until they start catching fire spontaneously on the road like my neighbor's New Beetle.

• #### Two irrelevant statistical numbers (Score:2)

The post has two completely irrelevant numbers: 1. fires "about 17 every hour" (why the rate of fires in the whole country important? Many cars -> many fires per hour). 2. "one fire for every 33 million miles" - useless number without providing comparable stats for gasoline cars, and normalizing to the car age, adjusting for causes of fire, etc. C'mon editors and writers, don't be lazy bums - there is enough of this stupid garbage in "mainstream media".
• #### Re: (Score:2)

Read TFA, the numbers are right there. "One fire for every 20 million miles" is the stats for normal cars.
• #### Re: (Score:2)

stats for normal cars

The stats used include the entire US fleet, including every neglected, run down, ancient, fire prone junker on the road with their untold accumulations of poorly done repairs, low quality replacement parts and ill-considered modifications. A legitimate comparison would consider only new manufacture gasoline cars.

That's not what we have here. What we have here are Tesla advocates advocating. Nothing more.

• #### Oh, the Humanity! (Score:2)

Tesla down, Bitcoin down, what's Slashdot going to push when they fold?

• #### Let them hype all they want (Score:5, Funny)

on Friday November 08, 2013 @08:42PM (#45374061) Homepage Journal
Makes the stock cheaper for me to buy. Once they figure it out and it recovers, \$\$\$

-T

• #### going per mile is not a great measure (Score:3)

on Friday November 08, 2013 @09:24PM (#45374329)

Since the biggest factors in car fires (mechanical failure, electrical failure, being in another fire and arson) all are active not just when the car is moving but when it is still.

The number of fires expected for Teslas in collisions at this point in time is about 1.25. We're looking at 2 or 3 right now (depending on whether you count Mexico).

This is above average and thus a valid reason to investigate.

Some math:
99.7% of collisions do not result in fire. About 11M cars are in collisions per year in the US, out of 250M cars. So about 4.4% of cars are in collisions per year on the road and 0.0132% of cars will catch fire due to collisions in a year on the road.

Tesla has about 20,000 cars out there, for about 6 months (on average), or about 10,000 car-years so far on Teslas. You would expect thus 1.32 car fires so far due to collision.

We have 2 or 3 depending on whether you count the Mexico fire. There is a case for not counting it, since all the other stats I list are US-only.

Given that car fires of all types rise with the age of the car since the fire prevention mechanism age and become less effective, having 2 or 3 car fires due to collision in 10,000 car years is perhaps alarming.

Either way, despite what greencarreports says, this rate of collision fires seems high enough to warrant an investigation, even with the small sample size.

• #### Three out of how many Teslas? (Score:2)

Had this happened to a mere handful of Toyotas or Hondas or Nissans, every politician would have been clamoring for somebody's head and lawyers would have been filing lawsuits right and left.

Sure, car fires aren't rare, but when they happen amongst so small a group of cars you have to take notice. What percent of Teslas are burnt toast now? I bet it's a higher percentage than burnt Nissans.

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