Fire Extinguishers

[JustinW]

I got a phone call today to say one of our club trucks had suffered an engine fire. This is the second engine bay fire in as many weeks our club has suffered.

The disturbing thing is, in both cases 0.9kg dry powder fire extinguishers failled to deal with the fire!

In the first case a fairly standard Nissan Patrol caught fire due to the wrong breather hose being installed some time in the past. The oil degraded it and it split spraying oil onto the exhaust. Two 0.9 kg dry powder extinguishers were discharged onto it with no effect. The owners exact words were "pi@#ing on it would have achieved more" Luckily he also carries a 2kg dry powder and that worked.

The second case, this morning, involved a lexus powered hilux that that was being driven to work. It ruptured a fuel line and sprayed petrol around with caught fire. A 0.9kg dry powder has no effect, neither did half a box of beer (the only other liquid on board). It was put out when a guy stopped who had a Riger (a 20L knapsack sprayer with a bit of foam in it that forestry crews carry)

The first guy has done a bit of research since and has found that all dry powder extinguishers are not created equal. Cheap ones have different powder than more expensive ones. Also 0.9kg ones don't deliver it fast enough for a fuel/oil type fire. As well, cooling also helps to prevent reignition.

So I'm off to talk to the local fire safety officer tomorrow and work out what other extinguisher I will be buying myself for Xmas!

[geeves]

I carry a 1.5kg for this reason as well as the fact that the brother in law worked for chubb when I replaced the old one. Anouther thing to think about with extinguishers is that the powder settles with the normal gentle vibrations you get in a 4wd so you might find that when you go and use it all you get is the propelant and not the powder you realy want.
Just had a look at the rules of the 2 clubs I belong to re extinguishers One club just states extinguisher the other is more specific in that it specifies 0.9kg dry powder and also demands the extinguisher is removed from the bracket and shaken at every anual inspection. The logic behind the smaller size extinguisher was that in a club trip several extinguishers will be available which if used simultaniously do achieve what a larger extinguisher will. This theory wouldnt of helped in your case
This is a good reminder to everyone to check there extinguishers.

[roga]

I carry a Co2 extinguisher, not sure of size but its about 6" round and 18" long. Works awesome, never had a problem on any fire.
The dry powder ones are very corrosive on the vehicle & are dearer to fill also.

[geeves]

The active powder in a fire extiguisher is either sodium bicarbonate in the cheap extiguishers or calcium bicarbonate in the more expensive ones. Add a few things to stop it settling into one solid lump and a way of producing high presure gas propelant and you have an extiguisher. The first one is also known as baking soda.
These definatly should be washed off as soon as possible but I wouldnt call them very corrosive.

[JustinW]

Talked to the fire safety officer at the local fire station today and he recommends dry powder at least 2kg

[roga]

The reason I said very corrosive is because I have seen the result of a dry powder extinguisher being used on a motorcycle. The aluminum motor showed definite pitting after a few days. So yes wash everything throughly after using them, I think I'll stick to Co2. ;D

[Garth]

Dry powder definately makes a big mess and can kill electrical systems if not promptly washed up. Auckland club and most forrestry areas require a minimum of 2kg dry powder per vehicle. I have one mounted on passengers door, and other inside small rear door on right. Had to use it once when my alternator oil seal went and it caught fire, seemed to go out ok but was only hot oil, not fuel so a bit easier to sort out. Key to putting out fire is to try and remove the fuel, eg turn off fuel pump etc.
A CO2 extinguisher would definately be a good idea also.