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Renmoo
08-09-2006, 04:37 PM
... when a car with a fire extinguisher caught fire? If the fire extinguisher explodes, would the foam or carbon dioxide gas in it be released, and therefore extinguishes the flame? This scenario sounds logical unless a chemical reaction is needed to occur in a fire extinguisher before it can be used.

Cheers :)

piersdad
08-09-2006, 08:10 PM
by the time it is hot enough to explode it will be so hot that it would actually cause the already hot flames to cause more damage.
even spread th efire.
an extinguisher is only good if it can get to a minor fire as soon as it starts

Renmoo
09-09-2006, 12:47 PM
But... wouldn't the sudden outburst of carbon dioxide gas create an "oxygen-debt" environment around the car, and therefore quelling the explosion?

Cheers :)

Greven
09-09-2006, 01:05 PM
But... wouldn't the sudden outburst of carbon dioxide gas create an "oxygen-debt" environment around the car, and therefore quelling the explosion?

Cheers :)
The CO2 would be under such pressure at the time it explodes that it will be spread out over a huge area (and so will fragments of the extinguisher) so it won't be concentrated enough to put out flames.

netchicken
09-09-2006, 01:28 PM
Actually someone said don't bother having an extinguisher in a car, stick it in your kitchen instead. If the car catches alight the insurance will cover it, and the safety aspect of having it in the house is better.

(just an aside)

Graham L
09-09-2006, 01:41 PM
You won't burst a CO2 extinguisher. They are tested to well over 3000 psi. You might pop the safety rupture disc, but the oxygen deficiency wouldn't put out the file. A lot of the CO2 effect is the cooling of the focus of the fire. You won't get that. Anyway, by the time things got that hot in the car, what would be the point? It's all over. A CO2 would not be installed in a motor vehicle.

You'd have a dry powder, which might burst ... but again would not be very useful. The bicarbonate works by being directed on the hot spot, which it smothers with the CO2 it produces. If it's dispersed as it would be by bursting) (a steel) or melting (an aluminium one) bottle, or even melting or blowing off the cap/handle/nozzle assembly it would be not concentrated enough to work.

You certainly would not want a foam extinguisher. I suspect it would still be intact in the smoking ruins when the fire had gone out of its own accord. It would take a long time to boil the water in it and then produice enough steam pressure to burst the can. :D

As for the aerosol "fire-extinguishers" sold kitchens and cars, they would certainly burst. But they're no use for putting out fires even when used as intended.

I suppose you could install a proper sprinkler system. Water is quite a good
fire extinguisher. :D In a sprinkler system the heads have a bursting capsule which releases the water through a nozzle when the capsule reaches about 60 degrees.

piersdad
09-09-2006, 01:57 PM
As for the aerosol "fire-extinguishers" sold kitchens and cars, they would certainly burst. But they're no use for putting out fires even when used as intended.
had a fire in my car and woopee had a proper aerosol fire extinguisher and the wiring loom of the car was well alight.
used the extinguisher and it did no effect at all.

so i jumped up on the mudguard and peed on it
that was more effective
put the fire out easily

drcspy
09-09-2006, 02:21 PM
I once had the misfortune to be first on the scene of a nasty accident when two vehicles had collided......one a small ute was blazing fiercly with the two travellers still inside...........(they were dead as and cooking well and it was only perhaps less than a minute after the crash) anyway during the next 20 mins or so about a dozen people turned up with fire extinguishers and they simply weren't sufficient to extinguish the fire.....in fact they did damn all......it wasn't till about half an hour later when the fire truck arrived that the fire went out.......a fire extinguisher may be handy but dont rely on it to stop a car fire theres just too much highly flammable plastic etc in there for such a small device to deal with.....