A car fire insurance investigator e-mailed me about 6 months ago wanting to do a story about this. Apparently something like 20% of all car fires are caused by discarded fag ends being sucked into following vehicles.
HJ
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I do not know if you looked under the bonnet of a C5 2.2HDI Excellence but it appears to me that it would be impossible for anything to be sucked into the engine compartment of this vehicle, particularly as it is mostly enclosed, even to having a tray under the engine etc. Any way, how can a FIRE RESISTANT cover be caught alight by a cigarette end? It says a lot for the FIRE RESISTANT material used by Citroen? Your comments would be appreciated.
BJ
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This is copyright Steve Hannaford so cannot be reproduced for gain without his permission:-
The book was published mid-June. It is called "Steve Hannaford's method for the investigation of vehicle and automotive fires"
Steve Hannaford
Hannaford Forensic Services Ltd
PO Box 2104
Wrexham LL11 3AQ
tel:01978 790390
fax: 01978 790490
email: hannaford@clara.co.uk
CIGARETTES AND INCANDESCENT MATERIAL
What are the chances of a cigarette end which has been thrown out of a car being able to start a fire in the vehicle behind? This could only be, perhaps, a one in a thousand chance. Well, if you stop and think that there may be ten thousand cigarette ends thrown out of car windows every day, that means ten vehicle fires per day might be caused by those thrown out cigarette ends. I?ve suggested ten thousand, but the figure might well be closer to one hundred thousand, or even one million! When you extrapolate the figures, the results are quite frightening.
Everyone knows the old story about the cigarette being thrown out of the driver?s window only to enter by the open rear passenger window and start a fire on the back seat. I have only ever had one or two fires caused by this. No, what I am talking about here is the cigarette end that is thrown out of the window of the car in front and gets either sucked into the air-filter of the car behind, or manages to pass through a gap in the radiator grille and comes into contact with the combustible under-bonnet lining.
I am now going to tell you something that may surprise you: in our experience, perhaps fifteen or even twenty percent of all car fires that occur on motorways and dual-carriageways are caused by cigarette ends thrown out of vehicle windows either being sucked into the air-filter or becoming lodged in contact with the under-bonnet lining of the car directly behind.
This whole scenario is, I am told, far more prevalent in countries where they drive on the left ie with right-hand drive vehicles. The reasoning for this is that the majority of us are right-handed - and ashtrays in virtually all right-hand drive vehicles are built into the centre console to the left of the driver. Hence, it is easier to throw the cigarette end out of the window than to change hands and stub it out in the ashtray. In left-hand drive countries, the ashtray is to the right of the driver, and so it is easier to use.
Older cars do not suffer in the same way, because the intake air is usually drawn into the air-filter from within the engine compartment, ie from behind the coolant radiator. This offers a high degree of protection from cigarette ends, though the air is first warmed by passing through the radiator. In the quest for more power, colder, denser air can be drawn into the air-filter box by locating the intake opening forward of the coolant radiator, and this is the major factor in more modern vehicles that gives rise to the cigarette end problem.
Another plus for older cars is the air-filter box being made of pressed steel. This does not prevent the fire starting on the air-filter, but limits the speed and extent of development out into the engine compartment.
Manufacturers are well aware of the propensity for this to cause fires, and will often cite it on the basis that it is some sort of ?Act of God? Frankly, I was unaware that God was a smoker. In my view, if manufacturers are aware of the potential for this, then they should be designing their air intakes a little more carefully, and ensuring that the under-bonnet lining material is, at the very least, fire retardant. I would also have thought that by now, it would have been simple to design an intake system that was not susceptible to cigarette end ignition.
If you check through the DoT Vehicle Inspectorate recall list, you will find that three major commercial vehicle manufacturers have had to recall some of their vehicle models for modification. This was because, on right-hand drive models, the air intake was directly behind the driver?s window. Thus, when the driver disposed of a cigarette end out of the window, it could be immediately sucked into the air intake ducting, down onto the air-filter and a fire would ensue shortly afterwards.
The manufacturers took this problem very seriously. The view taken seems to be that, if the fault is occurring on a regular basis because the driver of that vehicle is (unwittingly) setting fire to it as a result of their own discarded cigarette end, this is different from the scenario where the cigarette end is thrown out of the window of the car in front by someone else. I know of one situation where a responsible manufacturer changed the position of the air intake on an articulated tractor unit from behind the driver?s window to the front grille. Unfortunately, this simply put it straight in line for those cigarettes thrown out of the window of the car in front, instead of those thrown by its own driver.
Incidentally, I had an experience where a commercial vehicle manufacturer changed the intake from the driver?s side (offside) to the passenger side (nearside) to alleviate this problem on its UK vehicles. This worked well, except we were then suddenly being instructed to investigate fires in road sweeping vehicles where the chassis and cab were made by this same manufacturer. The problem? Road-sweepers in the UK are left-hand drive (or have dual controls), so the driver is sitting on the left, directly in front of the air intake - and the discarded cigarette end was causing the problem once again.
Certain makes and models of cars are more prone to this than others. For instance, many of the Japanese manufacturers seem to put the air intakes right behind the headlamp cluster (still forward of the radiator). This makes it very difficult for the burning end of the cigarette to enter. I can certainly confirm that we have had very few Japanese vehicles having caught fire due to the cigarette end phenomenon. Likewise, one or two British and European manufacturers do not make our list of vehicles frequently set on fire by incandescent material, simply because of the location of the intake opening.
The problem is in not only making a grille that is small enough to stop a cigarette end from entering, but also ensuring that the layout of the intake is such that, when the cigarette end hits the grille mesh (or passes straight through and strikes the front of the radiator), and breaks up into small pieces of incandescent material, these cannot be sucked into the airbox and onto the combustible filter element. It seems that only a relatively small fragment of glowing material is sufficient to ignite the air-filter or other debris (for instance, dried leaves) in the air-filter box. This is because of the inevitable high flow of air through the air-filter while the engine is running. Likewise there is a possibility of the cigarette end, or incandescent fragments from it, getting trapped by or lodged up against the under-bonnet lining material when a cigarette strikes the front of the car.
Generally, in the case of the under-bonnet lining material catching fire, there will be a very distinctive burn pattern; the only item largely consumed in the fire will be the under-bonnet lining material, with corresponding damage to plastics at high level across the top of the engine compartment. In this scenario, I would not expect to see significant burn patterns lower down within the engine compartment, though length of burn time will be a factor if the fire manages to take hold.
With cigarette ends or incandescent material entering the airbox, there is a specific sequence of events that I should bring to your attention. This sequence of events is typical, though certainly not exclusive.
C Firstly, the type of roads that are being covered. Usually this will occur on dual carriageways and motorways where speeds in excess of 50 mph are being maintained. When the cigarette end is thrown out of the window of the car in front, it flies straight back into the engine compartment of the car behind without even touching the ground. Thus, fairly heavy traffic conditions, though where moderate speeds are being maintained, is the first event in the sequence to look for.
C Secondly, the discovery of the fire. Because the fire originates within the airbox, there will usually be no warning lights or electrical malfunctions in the first instance. However, there will be a loss of power. If the air-filter is burning and producing smoke, this will obviously drastically reduce the engine efficiency. The first the driver knows about the occurrence is a sudden loss of engine power - either while still travelling on the motorway or dual carriageway, or after they have just left it. Depending upon the engine compartment layout, electrical failure might rapidly follow. I have known several instances where the battery was next to the airbox, and there was a loss of supply before the car came to a halt.
C Thirdly, the fire will really only manifest itself to the occupants once the vehicle has come to a standstill. All the time the engine is running, it is sucking fire through the air-filter and intake ducting - through the inlet manifold, and throwing much of the smoke and products of combustion out of the exhaust. Once the vehicle has come to a standstill, if the engine is left running, the flow of air is greatly reduced; or very often the engine is turned off or might have stalled. Then the fire can burst out of the airbox and ducting - if it has not already done so.
The overall pattern of burning will be most severe around the air-filter, trunking and intake manifold. Nowadays, these manifolds are often made of plastic, and it is likely that it will have been burned away completely. I recall one instance where, to prove the point, the cylinder head was dismantled and the intake valves were found to have melted plastic around the seats. Thus, it was demonstrated that burning melted plastic was being sucked into the engine while it was still running.
Another part of the engine that will suffer in this type of fire (if fitted) is the turbo-charger. Often, the intake impeller will break up, depositing debris inside the intercooler.
It is always the exception that proves the rule, and I have had several instances where we have had a completely different set of circumstances, though the fire damage was still most consistent with this phenomenon. In all these instances, the vehicles had been driven slowly around ?B? roads with only moderate traffic, and several vehicles had been parked with the drivers having walked away before they realised something was wrong. In one instance the driver had noted a loss of power just as they were parking. In another, the first the driver knew there was something wrong was when the ignition light came on (this was because of the physical layout - the airbox was directly in front of the battery and associated fusible links). In these instances, the burn patterns were such that the fire could have only originated within the airbox. Ultimately, it might be an hour (or more) later if the cigarette only initiates a smouldering fire in the air-filter.
I remain of the view that if a manufacturer is aware of the propensity for their design of intake to attract incandescent material, then it is a design fault. I am continually amazed that manufacturers seize the opportunity to blame cigarette ends for starting fires in air-filters as if it is no fault of theirs. If one cigarette is to enter the intake of a new design of car for the first time, then I expect the manufacturer to take note and do something about it. I cannot see any excuse for continually blaming a cigarette end for having started a fire as if there is no responsibility on the part of the manufacturer to take action. It is, after all, entirely foreseeable, and they are well aware of the problem.
In the case of under-bonnet linings, these are often made from a mix of cotton with other fibres. The exposed surface is then treated with a (usually black) fire retardant finish. Note that ?fire retardant? does not mean ?fire proof?, as many in the automotive industry seem to think! There have been some major recalls because of the discovery, once a new model was released, that in normal use, the under-bonnet lining was all too frequently becoming ignited by cigarette ends discarded in the ways previously described. In one instance that I know of, a new (and still current) model was recalled for an alternator fault, and while that was being done, a new under-bonnet lining was also fitted, though the owner would not even be aware that this was done.
In another instance, where the under-bonnet lining was composed of a combustible cotton blend, a smouldering fire was discovered under the bonnet two days after the vehicle was last parked. The lesson therefore has to be that smouldering fires in either the air-filter or under-bonnet lining do not necessarily have to manifest themselves while the vehicle is being driven, nor even within minutes (or hours?) of being parked.
I am sure that the general public are simply not aware that the lining under the bonnets of their cars are combustible and, in many cases, easily ignited. I understand from one manufacturer that they found the answer was quite simple - mix the cotton blend with twenty percent glass-fibre, and apply the fire retardant coating to both sides.
In defence of the manufacturers, I do think that there should be some effort made to alert the general public to the dangers of throwing cigarette ends out of car windows. I do not know of an insurer suing a manufacturer over a fire started by a cigarette end thrown out of a car in front on the basis of a vehicle design flaw. I think there might be a legal argument that the manufacturer is not entirely responsible for a source of ignition that is external to the vehicle. Ultimately, educating drivers is the key. Efforts could be made to make it socially unacceptable to dispose of cigarettes out of vehicle windows. One day!
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That was interesting reading HJ.
Now lets have a campaign to make it an offence to smoke whilst the vehicle is in motion/driving.
DVD
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But if we campaign against smoking while driving someone might think using a mobile phone on the move is almost as dangerous and try to ban that too.
HJ
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There is a current German poster featuring a Hugh Grant lookalike:
cigarette, mobile, cup of coffee etc
Caption : Who's driving?
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But if we campaign against smoking while driving someone might think using a mobile phone on the move is almost as dangerous and try to ban that too.
But how many of us throw a mobile phone out the window :o)
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DVD, smoking whilst driving IS banned here in Jordan (along with using a mobile without a hands free kit)
www.middleeastwire.com/jordan/stories/20020121_2_m...l
"One youth, who was caught talking on his cellphone while smoking -- two separate traffic violations -- suggested ..." -
classic stuff!
CMark
PS spectacular posting about car fires, HJ.
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