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Permalink Reply by John Crabbe on August 28, 2012 at 12:23am

Since part of this discussion has turned to magnesium fires, it also depends on amount and context of such metal. While molten metal will react violently with the application of water, metal ingots don't.

 

To perhaps give a similar context, take an aircraft carrier, the wheels of the aircraft are magnesium in nature. The storeroom for such wheels is protected with a seawater sprinkler system. Also, the U.S. Navy, like the majority of fire depts, doesn't have Class "D" fire extinguishers, nor really carry enough sand to suppress a burning metal fire.

 

So when it comes to a car fire, and many perhaps have seen, the nice white light and sparks given off from a burning steering column or other areas with burning magnesium, yet the fires still seem to go out, don't they? How many depts out there are really carrying Class D extinguishers or enough sand to smother out the fire, or how many stop applying water if and when they see such a reaction? For the most part, such vehicle fires do come down to a cooling effect of the water. The water can intensify and speed up the amount of metal burning, thus depleting the fuel source of the molten metal. Cooling the vehicle with water can also prevent those metal parts from becoming molten and thus reacting with the water.

 

Quite basically, water is going to work for the majority of vehicle fires out there and even those with magnesium parts, the fuel will be used up faster with waster being applied, thus the reason that it seems "copious" amounts of water puts the fire out. On a vehicle fire, I don't worry much about burning metal, never once put sand on a vehicle fire, and we don't carry Class "D" extinguishers.

 

I will say, given a foundry fire or a dumpster outside a foundry on fire.......whole different ballgame all together.

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Permalink Reply by capcityff on August 28, 2012 at 8:58am

I agree with you John.  Water will still put out the fire.  I'm not worried about having to use sand or foam for a car fire.

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Permalink Reply by Marc Hansen on August 28, 2012 at 2:22pm

only time I have seen sand used was for a semi truck load with magnesium fully involved...they literally buried it in sand on the side of the road impressive to watch but cant imagine it would have been much fun for the responder 

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Permalink Reply by Andrew Dalgarno on September 23, 2012 at 12:36pm

Kind of related...

We responded a couple of years ago to a farm tractor on fire. Arrived and started pumping water only to have the engine begin to turn over! Yup, the water shorted out some wires and it was trying to start. Luckily for us the farmer had taken it out of gear. Since it was a diesel, (and on this tractor there was enough room to work), we were able to reach the fuel pump and pull the fuel shut off lever. Once the fire was beat back a bit, we disconnected the batteries!

Andrew

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Permalink Reply by captnjak on April 13, 2013 at 10:35pm

All vehicles, whether fire or accident, should be made as stationary as possible. Disconnect battery, chock tires or even tie off to something substantial (steep grade and off road scenario). I've seen many firefighters flatten tires with tools to keep car from moving. Not my favorite since we are causing more damage to vehicle. We are there to make things better, not worse.

In my experience, large amount of water will be suitable for any burning metal encountered at car fires. Knock down all other fire first and then hit burning magnesium until it goes out.

Shavings of flammable metals are extremely dangerous, much more so than a block of similar amount. I wouldn't recommend burning them except in very small amounts. For some flammable metals even the small amount of moisture contained in sand can cause a violently explosive reaction.

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Permalink Reply by Don Catenacci on April 13, 2013 at 10:58pm

Flattening the tires, while not my choice, is miniscule in the overall damge costs of a car fire.  Many insurance companies will total a vehicle if there is a substantial engine compartment fire.

 

Wheel chocks, or cribbing are a better choice to stop a car from moving than flattening the tires.

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Permalink Reply by captnjak on April 13, 2013 at 11:22pm

I agree; it doesn't take that much fire to total a car. There are some who want to take tires at every vehicle incident. This could be overkill, depending on circumstances.

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