Luton car park fire: ultimately not caused by EV

[tom66]

I didn't want to necromance the last topic we had on this (EV cement truck fire) - but the fire report from the car park fire at Luton Airport has now been released.  This fire resulted in the total destruction of Car Park 2 and the vast majority of vehicles within were lost (a few were recovered from the roof).  No one was injured.

https://www.bedsfire.gov.uk/sites/default/files/2024-10/Significant%20Incident%20Report%20LLA%20Car%20Park%202%20fire.pdf

Origin of the fire:

"The fire originated in a privately owned car powered by a diesel fuelled internal combustion
engine with the cause of fire determined to be accidental."

"The initial 999 call was ‘received by Bedfordshire FRS Service Control at 20:47:20 hrs by
Crew Manager Service Control B from the driver of the Range Rover that was on fire. When
questioned by Service Control, the caller advised their car was a diesel Range Rover that it
was located on the third floor.’ The subsequent fire investigation confirmed that the vehicle
was powered by a diesel non-hybrid internal combustion engine"

Conspiracy theories about this being a fire in a hybrid or converted car appear to be nonsense.  It definitely wasn't an electric car.  It's unlikely the exact cause will be determined (there's probably nothing left but the body shell); the origin appears to be around the engine area of the vehicle, and it occurred whilst the vehicle was in motion, so the possibility of an engine fault or a fuel rail leaking is there.  The driver noted that they had been driving for two hours without issue before the fire; if the vehicle was driven for a period of time on the motorway (Luton Airport is very well connected to a motorway) it is likely that components will have been under load for some time and perhaps the sudden cooling down caused an oil seal to fail, or a fuel rail leak occurred at that moment.

On fire spread in car parks:

"As they were making their way up the vehicle ramp from the second to the third floor BA
Team Alpha 2 observed that the fire was spreading to the second floor due to running fuel
and they retreated to extinguish this fire."

"Initial crews from Bedfordshire FRS have indicated they witnessed “running fuel fires”. This
is where fuels such as petrol and diesel have escaped from fuel tanks. Most modern vehicles
are manufactured with plastic fuel tanks, these are more susceptible to failure in the initial
stages of a developing fire. It was confirmed that the Range Rover involved was fitted with a
plastic fuel tank. Heat of the developing fire will have been sufficient to ignite some of these
fuels as they followed the sloping gradient of the roadway surface, spreading ignitable fuel
beneath vehicles and into the drainage system thus spreading to other floors beneath the
point of origin."

"On investigation looking through images taken by crews inside the car park it is evident
that drainage pipes within the car park are of plastic construction. The heat from the fire
and the running fuel fires entering the drainage system would have caused the pipes to
fail leading to fire spread."

Whether electric vehicles contributed significantly to the fire:

"In the immediate aftermath of the incident there was considerable speculation within the
press and across social media platforms about the fire originating from an electric vehicle
(EV). This was despite statements at the time from Bedfordshire FRS stating that the Service
believed the vehicle to a be a diesel vehicle. Subsequently it has been confirmed by the
fire investigation report that the fire originated in a diesel vehicle and the cause was
accidental."

"Similarly, the fire investigation report for Luton airport identifies running fuel fires and an
approximately 10 mph wind along with the design of the car park with narrow gaps between
the parked cars as being the factors contributing to the spread of the fire. The 10mph wind
is based on a reading taken in Luton at a lower level, it should be noted that London Luton
Airport is located at the top of a hill and fire was on the third floor."

It should be noted the author of the report doesn't specifically eliminate EVs as contributing to the spread, but crews reported running fuel fire as being the greatest hazard.  Such fires would be non-existent with EVs, and fire could only spread between vehicles by direct thermal exposure.  However, they do cite a report from the Norwegian fire authorities on a similar incident where wastewater from the fire was tested for quantities of lithium and cobalt:

"When it comes to the fire’s environmental impact, analyses of water samples in nearby water
bodies provide indications on the contribution of electric vehicle batteries (analyses carried
out by COWI,). The analyses included lithium and cobalt, main components of an electric car
battery. Lithium was not found in any of the water samples, and the analyses showed low
concentrations of cobalt. This indicates that batteries from burnt out electric vehicles have
not contributed to the pollution of nearby water bodies."

"Observations made during the fire, as well as water analyses in retrospect, thus imply that
electric car batteries were not involved in the fire. However, technical investigations of the
actual batteries of the burnt-out or partially burnt-out electric and hybrid vehicles are
necessary to substantiate this point and provide a definite answer."

TL;DR - there's no direct evidence of contamination due to burning batteries, but it's impossible to say certainly at this stage that EV batteries weren't involved.  However, the fire crews don't seem particularly bothered by this, and highlight lower risk (emphasis mine).

"Regardless of the type of engine the fire load of a car is significant. As such, if a car
catches fire there is a strong possibility of the fire spreading to adjacent vehicles. The
open sided design of most multi storey car parks means that wind can become a
contributing factor in the fire spread. The issue of running fuel fires does not occur with
electric vehicles."

Perhaps this will quell some of the speculation on EV fire risk... but I'm sure we'll still see plenty of YouTube posts from the likes of AutoExpert and friends about how this is the biggest risk ever in new vehicles and we'll all be seeing Tesla's bursting into flames left, right and centre if we don't stop them now and go back to those totally non-flammable combustion engine cars.

[TimFox]

The “narrow spacing” between cars in parking lots and structures is one of my gripes in general, and it makes sense with respect to propagation of fires.

[coppice]

The “narrow spacing” between cars in parking lots and structures is one of my gripes in general, and it makes sense with respect to propagation of fires.

Americans have things easy in car parks. In European car parks we normally have to hold the car door as we open it, and carefully squeeze out, or we will scratch the door of the next car. They've also shortened the spaces in recent years. 30 years ago a car like a BMW 5 or a Volvo V90 would fit lengthwise in most car park spaces. Now the last half a metre sticks out.

[Monkeh]

The “narrow spacing” between cars in parking lots and structures is one of my gripes in general, and it makes sense with respect to propagation of fires.

Americans have things easy in car parks. In European car parks we normally have to hold the car door as we open it, and carefully squeeze out, or we will scratch the door of the next car.

To be fair, that's my experience in many American car parks. Then again, that experience has also predominantly been in a Chevrolet Tahoe, which is approximately the size of a bus.

We started making car parking spaces smaller to suit the sizes of car popular in the 90s and early 2000s, just in time for everyone to 'decide' (be told) that what they really want is a large SUV.

[ajb]

A big but easily-overlooked factor in the intensity of vehicle fires is all of the plastic they contain -- particularly in the interior, but there's plenty under the hood and in the body as well -- and that's equally true for EVs and ICE vehicles.  You don't need any gas/diesel or batteries to turn a car into a giant fireball when you have all those solid hydrocarbons sitting there. 

[TimFox]

The “narrow spacing” between cars in parking lots and structures is one of my gripes in general, and it makes sense with respect to propagation of fires.

Americans have things easy in car parks. In European car parks we normally have to hold the car door as we open it, and carefully squeeze out, or we will scratch the door of the next car.

To be fair, that's my experience in many American car parks. Then again, that experience has also predominantly been in a Chevrolet Tahoe, which is approximately the size of a bus.

We started making car parking spaces smaller to suit the sizes of car popular in the 90s and early 2000s, just in time for everyone to 'decide' (be told) that what they really want is a large SUV.

My American experience with narrow parking spaces is mainly with privately-owned parking garages.
There's an old suggestion for parking lots in shopping centers and similar places:  when the center first opens, make the spaces large so that the lot looks busy.
Later, as the center ages and business improves, reduce the spacing.
Luckily, I no longer own a 1970 Buick two-door sedan, where the doors must open wide enough to allow use of the spacious rear seat.

[Siwastaja]

It's the same story every ****ing time 

Cars burn all the time, left and right. They always did. No one was interested before about 2020.

Now when cars burn, main stream media speculates that it must have been caused by EVs, with zero evidence. Alternative media, political or non-political, speculates that it must have been caused by EVs, with zero evidence. The bigger the fire, the longer they keep speculating. And they don't even say they are speculating. They are running headlines of "EV fires" like their speculation is some kind of verified fact.

Month or two or three passes, and investigation reveals exactly what was known from the start; that as always, ICE cars caught fire. Oopsie, but no news coverage. Not even a simple corrective article. Again no one's interested. Until the next fire, which of course must be caused by EVs because those EVs apparently cause fires all the time, remember all those previous cases which were in the media for months!

[fred001]

FWIW many older cars burnt when ethanol was added to gasoline

https://forums.aaca.org/topic/257239-an-interesting-article-by-jay-leno-on-ethanol/

[tom66]

Can barely believe this bit:

"Station Commander A notes that:

‘At some point, I was made aware by Police that a person had been spotted within the
car park. I radioed Watch Commander A to establish if this was one of our personnel
or, a member of the public. Watch Commander A got back to me very quickly and
confirmed that they had located a LLA worker and they were now out of the building.’

It has since been established that the LLA worker referred to in Station Commander A’s
contemporaneous notes worked for another organisation and was based in the terminal
building. This individual entered the car park in an attempt to retrieve their car which was
parked on level 3. They told Watch Commander A who rescued them that they had used
their position as a worker at the airport to gain access. 39 It is estimated that the entry of the
worker into the car park and the subsequent rescue occurred between 21:30 and 22:17."

This almost became a fatality... some people are unbelievable.  It's a car!  It can be replaced!  You can't!!

For reference, the structure was considered "fully ablaze" by 21:37 (major incident declared), and the fire started on level 3...

[electr_peter]

In short: car caught fire (which is not such a rare occurrence), initial fire was not contained, then fire spread and things went south. Failure to extinguish initial fire quickly is the most important part.

Fire spread because of fuel spill from melted plastic fuel tank on slanted floor. Would EV be worse or better? Maybe at initial stage it could be better, but not sure overall. If nearby ICE cars catch fire and spill fuel themselves, then initial fire source (EV/ICE) is not that relevant.
According to firefighters, once EV batteries goes on fire, it is almost impossible to extinguish as regular car/fuel fire (batteries are on fire within frame shielded from external influence) and even burns a bit hotter than ICE car (thus massive damage to parking structures). Point on EV vs ICE fire safety is moot.

One of the scariest part about the fires is that there is no need for fire to make direct contact with objects nearby to spread - heat radiation alone is sufficient.

[Someone]

"Similarly, the fire investigation report for Luton airport identifies running fuel fires and an approximately 10 mph wind along with the design of the car park with narrow gaps between the parked cars as being the factors contributing to the spread of the fire. The 10mph wind is based on a reading taken in Luton at a lower level, it should be noted that London Luton Airport is located at the top of a hill and fire was on the third floor."

This is really bizarre, complaining about the quality/availability of wind measurement data... at an Airport. Is there a lack of instrumentation because pilots using the airport have never needed accurate information about the wind at various altitudes and positions?

[tom66]

In short: car caught fire (which is not such a rare occurrence), initial fire was not contained, then fire spread and things went south. Failure to extinguish initial fire quickly is the most important part.

Fire spread because of fuel spill from melted plastic fuel tank on slanted floor. Would EV be worse or better? Maybe at initial stage it could be better, but not sure overall. If nearby ICE cars catch fire and spill fuel themselves, then initial fire source (EV/ICE) is not that relevant.
According to firefighters, once EV batteries goes on fire, it is almost impossible to extinguish as regular car/fuel fire (batteries are on fire within frame shielded from external influence) and even burns a bit hotter than ICE car (thus massive damage to parking structures). Point on EV vs ICE fire safety is moot.

One of the scariest part about the fires is that there is no need for fire to make direct contact with objects nearby to spread - heat radiation alone is sufficient.

I don't agree.  In order for an EV battery to go into thermal runaway, it needs to be exposed to a continuous external temperature in excess of 200C for about 5-10 minutes.  This would be sufficient to get cell internals beyond the critical temperature of around 200C to trigger a thermal runaway event resulting in self ignition.

Those situations can occur at the floor of the vehicle, in particular if the car interior were to burst into flames through other means.  But it's unlikely to occur before the rest of the vehicle is on fire.  And at that point, car fires between EV and ICE are about identical.  See Table 5 here - it shows that HRR (heat release rate) of EV and ICE fire in tests work out around the same at 5-8GJ.  But the EV cannot spill fuel to easily combust the vehicle next to it, the fire can only spread by heat.

Certainly different techniques and precautions are required in fighting these fires, but it seems that a parking garage full of EVs would actually represent an overall lower risk due to less fuel available to spread around.  Providing the fire could be contained within a floor, it would be unlikely to spread elsewhere, whereas with the Luton fire, burning fuel travelled through drainage systems and down ramps to ignite other vehicles, and fuel tanks quickly failed once the ambient temperature was above the melting point of the plastic.  Plastic fuel tanks are only required to withstand a small external flame for two minutes (UNECE Regulation 34, Annex 5, paragraph 5.1).  HDPE fuel tanks will melt at around 200C, rapidly releasing all of that additional fuel into the fire. 

[electr_peter]

In short: car caught fire (which is not such a rare occurrence), initial fire was not contained, then fire spread and things went south. Failure to extinguish initial fire quickly is the most important part.

Fire spread because of fuel spill from melted plastic fuel tank on slanted floor. Would EV be worse or better? Maybe at initial stage it could be better, but not sure overall. If nearby ICE cars catch fire and spill fuel themselves, then initial fire source (EV/ICE) is not that relevant.
According to firefighters, once EV batteries goes on fire, it is almost impossible to extinguish as regular car/fuel fire (batteries are on fire within frame shielded from external influence) and even burns a bit hotter than ICE car (thus massive damage to parking structures). Point on EV vs ICE fire safety is moot.

One of the scariest part about the fires is that there is no need for fire to make direct contact with objects nearby to spread - heat radiation alone is sufficient.

I don't agree.  In order for an EV battery to go into thermal runaway, it needs to be exposed to a continuous external temperature in excess of 200C for about 5-10 minutes.  This would be sufficient to get cell internals beyond the critical temperature of around 200C to trigger a thermal runaway event resulting in self ignition.

The point is that initial EV fire can start because of internal thermal runaway which is very bad. Whether or not EV cars nearby can go into thermal runway because of external fire for some time is not a point I made. Main point is that once fire starts (whether from EV or ICE) and is not contained, it spreads. If initial fire can spread faster though EV or ICE vehicles nearby, I am not sure - both cases are terrifying.

[IanB]

This is really bizarre, complaining about the quality/availability of wind measurement data... at an Airport. Is there a lack of instrumentation because pilots using the airport have never needed accurate information about the wind at various altitudes and positions?

The airport surely has full meteorological information available. As with all airports, it issues meteorological bulletins (METARS) to pilots on at least an hourly basis. No idea why they didn't make use of that information.

[SiliconWizard]

I'm curious about self-combustion of parked, still cars being that "common". I luckily have very rarely seen that myself. And the rare occurence were very old stuff from mainly electrical short-circuits. Does anyone have statistics about it?

[nctnico]

This is really bizarre, complaining about the quality/availability of wind measurement data... at an Airport. Is there a lack of instrumentation because pilots using the airport have never needed accurate information about the wind at various altitudes and positions?

The airport surely has full meteorological information available. As with all airports, it issues meteorological bulletins (METARS) to pilots on at least an hourly basis. No idea why they didn't make use of that information.

Because it is a different department. I once visited the offices of a very large airline company (for work) and needed a specific department so I went into an office and asked. Nobody knew. Turned out the department I was looking for was 4 doors next to the office I went in to ask. FFS    And then I needed a key to enter an equipment room. Since nobody knew which key was needed, I ended up in an 'office' looking exactly like this:

[nctnico]

In short: car caught fire (which is not such a rare occurrence), initial fire was not contained, then fire spread and things went south. Failure to extinguish initial fire quickly is the most important part.

A sprinkler installation would help a lot to at least cool cars down next to the fire.  In underground garages, you typically find a combination of doors which shut off the air supply (and dividing the garage into sections) and sprinkers. I still wonder how a diesel vehicle could catch fire. It must have been an electrical problem as diesel fuel is very hard to ignite using a flame.

[Marco]

According to firefighters, once EV batteries goes on fire, it is almost impossible to extinguish

Just like it's almost impossible to quickly open a hole in a mangled car without jaws of life. It's a question of tools.

EV firefighting tools will have to become standard kit same as hydraulic rescue tools and rescue saws.

[SiliconWizard]

I still wonder how a diesel vehicle could catch fire. It must have been an electrical problem as diesel fuel is very hard to ignite using a flame.

Exactly.
And even gasoline or ethanol, ignitiing that requires at least a spark (and that would be rather unlucky, try to ignite some ethanol with just a spark in your lab). But diesel fuel? No way.

[tom66]

I'm curious about self-combustion of parked, still cars being that "common". I luckily have very rarely seen that myself. And the rare occurence were very old stuff from mainly electrical short-circuits. Does anyone have statistics about it?

I think it was Ford that had a recall on their cars where a fire could start shortly after being parked up as they had a fan override circuit that would run the fan for 5 minutes after the car  stopped.  This was designed to improve reliability, unfortunately the circuit itself could cause a vehicle fire.  Personally I know my dad had a Mercedes that spontaneously combusted after being parked up.  No cause was determined and the car was a write off though it was 20 years old at the time so perhaps it was a case of a worn out seal or something leaking hot oil onto an exhaust or other component.

I still wonder how a diesel vehicle could catch fire. It must have been an electrical problem as diesel fuel is very hard to ignite using a flame.

Exactly.
And even gasoline or ethanol, ignitiing that requires at least a spark (and that would be rather unlucky, try to ignite some ethanol with just a spark in your lab). But diesel fuel? No way

A lot of people seem to get hung up on this, but a diesel vehicle doesn't need diesel fuel to combust.  It could quite well be an issue with an oil seal failing, or a fault with a 12V electrical system, that provides the origin of the fire.  Once some plastics begin burning a small ignition source can rapidly become a large fire.  A leak in the high pressure fuel rail can cause atomised diesel to be spread throughout the engine compartment; this can be combusted more easily by a spark or hot components.  Engine coolant and ATF are typically flammable too.

[Monkeh]

I still wonder how a diesel vehicle could catch fire. It must have been an electrical problem as diesel fuel is very hard to ignite using a flame.

Exactly.
And even gasoline or ethanol, ignitiing that requires at least a spark (and that would be rather unlucky, try to ignite some ethanol with just a spark in your lab). But diesel fuel? No way

A lot of people seem to get hung up on this, but a diesel vehicle doesn't need diesel fuel to combust.  It could quite well be an issue with an oil seal failing, or a fault with a 12V electrical system, that provides the origin of the fire.  Once some plastics begin burning a small ignition source can rapidly become a large fire.  A leak in the high pressure fuel rail can cause atomised diesel to be spread throughout the engine compartment; this can be combusted more easily by a spark or hot components.  Engine coolant and ATF are typically flammable too.

Brake fluid is also flammable. And for all flammable liquids, there's a 500C+ turbo housing and exhaust manifold waiting to meet them.

[coppice]

A lot of people seem to get hung up on this, but a diesel vehicle doesn't need diesel fuel to combust.  It could quite well be an issue with an oil seal failing, or a fault with a 12V electrical system, that provides the origin of the fire.  Once some plastics begin burning a small ignition source can rapidly become a large fire.  A leak in the high pressure fuel rail can cause atomised diesel to be spread throughout the engine compartment; this can be combusted more easily by a spark or hot components.  Engine coolant and ATF are typically flammable too.

When you look at the aftermath of an inferno in a glass, steel and concrete tower, its amazing what little more than a bunch of carpets and furnishings can do when they burn.

[coppercone2]

sometimes I wonder if electricity is easier to contain then fluids. Fluid leaks are so easy to get.

Even sticky fluids. Houdini

I heard about leaks even from the most advanced expensive fittings that seem even theoretically impossible. Soldering or brazing it together seems to work the best, but its never an option for the entire system.

Moreso, if the fluid interconnect is bad,
If you keep thinking about a fluid valve on a physics level, with a poppet, seat, etc... you think WTF is this shit??? A electrical switches reliability is so much more believable.


seriously your gonna tell me thats not gonna break??



you know your affordable car valves are probobly getting made on some thing like that

[Someone]

Brake fluid is also flammable. And for all flammable liquids, there's a 500C+ turbo housing and exhaust manifold waiting to meet them.

Various sources report that just about every fluid in a typical automobile is able to burn, for one example a fire department:
https://depts.washington.edu/vehfire/fuels/vehiclefluids.html

Flammable and combustible fluids:
Gasoline and diesel fuel
Coolant
Engine oil
Power steering fluid
Automatic transmission fluid
Brake fluid
Windshield washer fluid
Refrigerants and lubricants

[Analog Kid]

^^^^^ Coolant? Doesn't it contain too much water to be combustible?
All the others I have no trouble believing are inflammable. (Or flammable if you prefer ...)