Luton Airport Car Park Fire

[Geoff S]

Fires can start in any vehicle.  My brother worked at Trowel services on the M1 near Nottingham as a holiday job and a Reliant 3 wheeler spontaneously combusted after it had been refuelled (it was in the days when an attendant filled up for you).  I saw it a day or so later and there was very little left - the fibre glass burnt well!  Similarly, I was on my motorcycle near the Belfry Golf centre and there was a car on fire at the side of the road.  It's always happened and always rare but, in a multi-storey car park has a much bigger effect and will affect more people directly.

[Martin Harris - Moderator]

I don’t know that it’s ever been a rare occurrence. Although 65% of car fires in the UK are regarded as deliberate, it still leaves 35,000 accidental vehicle fires a year. 
 

Glass fibre is actually quite difficult to set on fire. I had a Reliant Scimitar and was constantly nagged by a workmate warning me that I was driving an unexplored bomb, awaiting the smallest spark to turn it into a flaming torch.  I did a small mod. to the cooling system which required removing a small piece from the body so I took it to work and set fire to it on a gas ring.  After a surprisingly long time, a small flame was observed and removing it from the gas immediately extinguished the flame.  On another occasion, luckily while working on the car, the oil pressure gauge pipe failed, firing a jet of oil at one of the exhaust manifolds which produced copious yellow flames. After stopping the engine, I literally blew the flames out.  I also gas welded new sill members to the chassis through holes cut in the floor.  When things got too hot, a wet rag was enough to extinguish the small flames.  It’s the petrol, oil, brake fluid, plastic and rubber parts that burn - the body shell may be destroyed in the process but there’s not much left in a metal car after a similar fire - and even less when aluminium is involved!

[john davidson 1]

Even before the advent of EV one could see now and then scorch marks on the road left by a vehicle fire. Maybe ten years or so ago I had to drive past a burning vehicle on the motorway.

The use of high pressure and common rail fuel injection was given as a  risk factor in crashes leading to introduction of G triggered cut off switches 

[FlyinFlynn]

17 hours ago, john davidson 1 said:

Even before the advent of EV one could see now and then scorch marks on the road left by a vehicle fire. Maybe ten years or so ago I had to drive past a burning vehicle on the motorway.

The use of high pressure and common rail fuel injection was given as a  risk factor in crashes leading to introduction of G triggered cut off switches 

Indeed one would see the after effects of ice vehicle fires as scorched and slightly melted tarmac - that is a far cry from bent and twisted steel columns and fused concrete decks that we are starting to see these days... what is the difference?    Lithium burns at twice the temperature of  gasoline (2000 C vs 1000 C). Both concrete and steel melt/burn around 1500 C.  Petrol fires can be extinguished by spraying with water to remove both temperature and oxygen , lithium fires cannot, they require total immersion to reduce the temperature of the lithium below its thermal runaway point - not something easily arranged at the roadside, especially so when it is already belching out toxic fumes and 2000 degree flames, so, at present, the only viable option is to let it burn itself out.

 

I see today's news has a proposal to mitigate the risks by mandating larger gaps between parked cars to facilitate fire fighting efforts (no doubt pushing up the cost of parking) - not much use if the idea is still to let them burn themselves out. 

[leccyflyer]

Worth noting that you frequently see a lot of "O" level chemistry applied to discussion of lithium fires, with tales recounting the volatility of lithium metal when exposed to the air, but our batteries don't contain any significant metallic lithium in their chemistry, the lithium is present as a salt or other compounds. Much of the flammability of the lithium batteries that we use in the hobby comes from the hydrocarbon-based electrolyte. Yes. there can be a small amount of metallic lithium in denritic growths in batteries which have been abused, but a lot of the talk is a grey-white, slivery herring. The electrolyte contains sufficient capacity to supply oxygen to mean that excluding oxygen from the fire - one of the key fire fighting elelents - isn't that effective. These lithium fires also need to be cooled and for the fuel source to be removed, which, as we've seen from many videos, is far from straightforward and often the only course of action is to let the fire burn itself out- and there is a lot of stored energy there to be dissipated.

 

[kc]

The subject seems to have switched from a diesel vehicle fire to lithium!   So as the current news topics are electric bicycle recharging fires ( Rip Off Britain today and yesterday )  what batteries do they use in bikes and do they use balance chargers like we do for electric flight?

[Don Fry]

Looking at the price of a lot of electric bikes, too cheap to be built with any quality. Hence …………

The bikes I’ve seen and used ( not el cheapo things) don’t have an external balance unit. But it’s possible the balance elements of the charging system is onboard the bike. 

[Ron Gray]

The battery packs on my eBikes have balancing built into them.

[Don Fry]

2 hours ago, FlyinFlynn said:

Indeed one would see the after effects of ice vehicle fires as scorched and slightly melted tarmac - that is a far cry from bent and twisted steel columns and fused concrete decks that we are starting to see these days... what is the difference?    Lithium burns at twice the temperature of  gasoline (2000 C vs 1000 C). Both concrete and steel melt/burn around 1500 C.  Petrol fires can be extinguished by spraying with water to remove both temperature and oxygen , lithium fires cannot, they require total immersion to reduce the temperature of the lithium below its thermal runaway point - not something easily arranged at the roadside, especially so when it is already belching out toxic fumes and 2000 degree flames, so, at present, the only viable option is to let it burn itself out.

 

I see today's news has a proposal to mitigate the risks by mandating larger gaps between parked cars to facilitate fire fighting efforts (no doubt pushing up the cost of parking) - not much use if the idea is still to let them burn themselves out. 

I havnt got time to research that lot in any detail, but I know adiabatic flame temperatures of lithium metal and carbon fuels are similar, iro 2000°C. There is no metallic lithium in a lithium, it’s lithium compounds and other stuff in the cells. I know, it’s a law of chemistry that a reaction doubles in speed (and lessens in speed) for each 10°C change in temperature. (So cooling spray will effect speed of burn, and while it keeps going perhaps, it can’t radiate energy as fast, cos it cooler. 
But I for one do not place too much faith in your sources, to many holes in the logic.

[Engine Doctor]

Diesel fuel will spontaneously ignite if sprayed or dripped onto very hot metal like an exhaust as will other auto liquids like brake fluid . We found this when attending RTC's or RTA's as they used to be called back in the 70's and 80's when  front wheel drive diesel cars were becoming more popular; The brake fluid reservoir on many cars would pop off the master cylinder on impact throwing brake fluid all over the hot exhaust just below it   result... a fire until it burnt out then a small fire usually followed that either went out or built as it ignited other bits . The Brake fluid reservoirs are generally fixed more firmly now . Petrol unlike diesel or Brake fluid  never seemed to ignite unless there was a flame or a spark or glowing metal. Now fire and emergency crews have EV's to contend with , Unlike petrol or diesel powered vehicles they are far mor difficult to extinguish due to design required to keep the battery protected from water ingress . Diesel and petrol fires are generally simpler to extinguish as the seat of fire or ignition point can be reached comparatively easier with a Jet / spay or powder extinguishing medium . This is not possible on an EV as the seat of fire or point of combustion is not accessible  . Only option is to protect surrounding risks until the battery consumes itself , then clean up the mess.

 

The Luton Airport fire was IMO a catastrophe that's been waiting to happen for many years and its could happen at virtually multi storey car park due mainly to cutbacks allowed by deregulation of building regs . Less on sight fire fighting equipment to put out a small conflagration before it gets away , no sprinkler/ Drencher system etc just to save money on the build . Any of these systems especially a sprinkler/ drencher system would probably have prevented the fire spread and associated damage/devastation . Think Triangle of fire , Fuel , Heat , Oxygen , remove any side of the triangle and fire will die out  and a drencher system would certainly of cooled the fire,

Deregulation of building / Fire regs has a lot to answer for Think back five years to Grenfell Tower !  Cutting regs allowing developers to make a bit more profit then spend  In Luton Air ports case Billions of pounds and years putting right the consequences.

As for temperature bending steel etc , A multistorey car park is basically a pile air rich chambers filled with Flams ( cars ) Temps will build in these furnace like conditions as air can be drawn or blown in.

 

Its silly for EV  or IC drivers to point a finger at one another saying their car is the less dangerous etc but they will .Any type car/fuel /battery etc is a fire risk albeit  in different forms . 

Edited October 18, 2023 by Engine Doctor

[Paul De Tourtoulon]

6 hours ago, Ron Gray said:

The battery packs on my eBikes have balancing built into them.

As did ours when we bought it 15 years ago, the only problem was that the battery's lost 60% of its capacity in less than 5 years and at 550€ the battery,,🤢,

[Don Fry]

Did I not read somewhere this week, source insurers, that the rate of fires per 100,000 cars was a shedload higher for hybrids, then IC Fuel cars, and full electrics were an order of magnitude less.

[Ron Gray]

1 minute ago, Paul De Tourtoulon said:

As did ours when we bought it 15 years ago, the only problem was that the battery's lost 60% of its capacity in less than 5 years and at 550€ the battery,,🤢,

That's why they're fitted with pedals!

[Don Fry]

Just now, Ron Gray said:

That's why they're fitted with pedals!

And even, batteries lasting 15 years, I’m in.

[kc]

It would seem that people may claim from their own insurance company and thereby lose their no claims bonus.    However it seems clear that the vehicle that caused the fire can be identified - if that vehicle had collided with a stationary parked car then you would expect that vehicles insurance to pay for the damage.   Why should it be any different if it causes a fire and destroys someone elses vehicle?    Maybe one should not be in too much of a hurry to claim off your own insurance and losing a no claims bonus?

My own experience of losing my sixty years of no claims ( yes 60 years! ) due to thieves who stole the catalytic convertor on 2 different occasions from my hybrid makes me question the wisdom of claiming while expecting the " Protected No Claims Bonus" to prevent it costing me more the next year.  Frankly the insurance company just put up the premium and refused to say why!   By next year or so  I would have been better off just paying for the parts myself ( about £700 each time) and buying a classic car or something to drive around in the many weeks the parts took to be available instead of letting insurers provide a courtesy car.  ( the availability of a courtesy car was the deciding factor in claiming)   So my advice would be to think very carefully before claiming on your  insurance!   

[Frank Skilbeck]

2 hours ago, Engine Doctor said:

 

As for temperature bending steel etc , A multistorey car park is basically a pile air rich chambers filled with Flams ( cars ) Temps will build in these furnace like conditions As air can be drawn in or blown in by wind.

 

Another thing to consider is whether blast overpressure was design consideration, the heat would cause an increase in hydrocarbon vapours, when this reaches the lower explosive limit (LEL) then you basically get an explosion which causes a significant over pressure, it is part of the design of an oil and gas production facility to ensure the structure can withstand this,  as is the safe routing of hydrcarbon vapours from vessels subjected to a pool fire. The sprinkler system also keeps the vessels cool to prevent the steel from weakening which could lead to a Boiling Liquid Expanding Vapour Explosion, but in these systems the sprinklers are mounted directly on the vessel. In a carpark they would be spraying the body work and not necessarily cooling the fuel tank, so maybe you would need ground based sprinklers under every car.

[Don Fry]

Lost me there Frank. Wet, undamaged car, sitting on wet ground, getting constantly doused by cold water spray, how does a fire spread?

[Frank Skilbeck]

2 hours ago, Don Fry said:

Lost me there Frank. Wet, undamaged car, sitting on wet ground, getting constantly doused by cold water spray, how does a fire spread?

Burning petrol/diesel/oil floats on water, so can continue to burn, look at offshore accidents oil can quite easily burn on water. This runs under other cars and continues to burn, meanwhile the overhead sprinklers only cool the body work and not the fuel tanks/lines exposed to any flames under the car, this then adds more fuel to the fire, which the water can even help to spread the burning oil. Offshore the fire monitors are foam monitors, the foam making a barrier between air and the oil floating on water.

[Don Fry]

Frank, are you telling me, sprinkler systems in areas like car parks are assistors to fire spread, and have no reason to be. That the fire continues to spread as though they are not there. 
I don’t dispute foam is better, but people like the Royal Navy use water on ship fuel fires, not enough foam on board in their case. It works just fine. Cooling effect.

[Frank Skilbeck]

We do the same on offshore platforms, but the sprinkler system is specifically designed to keep the hydrocarbon equipment cool to prevent escalation, which is what would happen on board a ship, a roof mounted sprinkler system would cool the outside of a car so if the fire was contained to the initial car then it would stop the heat from that car igniting adjacent vehicles, but if, as shown in the Luton video, you have a fuel leak under the car and this is burning this could run under other vehicles setting fire to those, if a petrol car tank was then to leak you may get a vapour cloud which when it gets to a certain mixture would ignite. 

 

If you where designing a system with lots of fuel storage tanks you would make sure they were all bunded, vented to a safe area, etc

 

Part of the problem at Luton was that the hand held extingishers failed to operate thereby allowing the fire to escalate. A day after there was a taxi van fire at the pick up area at Glasgow airport but this was contained, but hey 2 diesel fires at 2 airport car parks and the issue is EVs

[Martin Harris - Moderator]

A major factor revealed in the investigation into the Liverpool car park fire was the rupturing of plastic fuel tanks (fitted to 85% of current cars) significantly contributing to the rapid spread of the fire.  Maybe time for a rethink?

[Shaun Walsh]

16 hours ago, Frank Skilbeck said:

Another thing to consider is whether blast overpressure was design consideration, the heat would cause an increase in hydrocarbon vapours, when this reaches the lower explosive limit (LEL) then you basically get an explosion which causes a significant over pressure, it is part of the design of an oil and gas production facility to ensure the structure can withstand this,  as is the safe routing of hydrcarbon vapours from vessels subjected to a pool fire. The sprinkler system also keeps the vessels cool to prevent the steel from weakening which could lead to a Boiling Liquid Expanding Vapour Explosion, but in these systems the sprinklers are mounted directly on the vessel. In a carpark they would be spraying the body work and not necessarily cooling the fuel tank, so maybe you would need ground based sprinklers under every car.

Brought back memories of Flixborough.

[FlyinFlynn]

On 18/10/2023 at 13:05, Don Fry said:

I havnt got time to research that lot in any detail, but I know adiabatic flame temperatures of lithium metal and carbon fuels are similar, iro 2000°C. There is no metallic lithium in a lithium, it’s lithium compounds and other stuff in the cells. I know, it’s a law of chemistry that a reaction doubles in speed (and lessens in speed) for each 10°C change in temperature. (So cooling spray will effect speed of burn, and while it keeps going perhaps, it can’t radiate energy as fast, cos it cooler. 
But I for one do not place too much faith in your sources, to many holes in the logic.

How do you explain the melted decks in the dutch oven or the melted steel structure in the Luton car park then?   Something got very warm and if not the chemicals in the battery then what?

 

Luckily I am not too lazy to look for evidence that your skepticism is misplaced.

 

"Measured flame temperatures as high as 1069 °C for single cells [8] and 1500 °C for a battery module [9] have been reported. In addition, there is evidence that observed mass loss rates decrease dramatically during evolution of the flame [4,6,8,9,12]."

https://www.sciencedirect.com/science/article/pii/S0378775320308892

 

"Battery-powered vehicles account for a small share of car fires, but controlling EV fires is difficult. Typically, an EV fire burns at roughly 5,000 degrees Fahrenheit (2,760 Celsius), while a gasoline-powered vehicle on fire burns at 1,500 F (815 C). It takes about 2,000 gallons of water to extinguish a burning gasoline-powered vehicle; putting out an EV fire can take 10 times more."

 

https://theconversation.com/lithium-ion-battery-fires-are-a-growing-public-safety-concern-heres-how-to-reduce-the-risk-209359

 

and that is just the first google page. 

 

 

[Martin Harris - Moderator]

There are so many factors involved here.  Did the car park even have fire resistant coatings on its structural beams?  Steel reinforced concrete is a composite - neither component is strong enough in isolation and rebar loses significant strength at fuel fire temperatures. The steel will expand - but the concrete won’t to any significant extent, causing cracking. 
 

How many EVs were on the upper floors of the World Trade Centre?  A number of laptops no doubt but the major fuel source was kerosene and furnishings. 

[john stones 1 - Moderator]

No expert on fires nor have I an agenda, dunno what temperature coke burns at, but when I was Blacksmithing we got it hotter by blasting air in, leave your work in forge too long and it melted ? Complex thing is fire and many factors at play in the various types.