From: Cav43rdBn@aol.com
Date: Sun Feb 17 2002 - 23:11:46 PST
As a fireman, I can toss out these couple of thoughts.....
As a general rule, Aaron is correct in saying that water will not
put out a magnesium fire. In most cases, adding water to a
magnesium fire will only result in a rather spectacular fireworks-type
display of sparks, scattered magnesium pieces (which can start
additional fires!), and further feed the fire when the hydrogen and
oxygen split due to the heat.
However, fire depends on a heat source, a fuel and oxygen to feed
itself and to continue it's destructive behavior. Usually, dumping
water will only continue to feed it, due to giving it oxygen as the
water molecules break down. (Sort of like water on Willy-Pete)
But, if you dump enough water on it, fast enough, it will cool the
fire and break the "fire triangle", thus extinguishing the fire. But,
we are talking about a *LOT* of water, real fast.
I'm sure that everybody on the list has probably heard of the old
VW Bugs having the magnesium engine blocks. They switched
them to another metal (I'm not a VW buff....) a few years later
into production, but the first couple years are potential fireballs
awaiting.
Not too long ago, we were called to an auto fire, arriving to find
an old-model Bug fully involved. The bumper line knocked down
the majority, but the engine continued to burn happily along.
After a few of the above mentioned fireworks displays, it became
obvious that the hose wasn't doing it's thing. Our OIC finally
decided that enough was enough, and used the Engine to push
the Bug into the nearby construction drainage pond. Fire out,
problem solved, except for some terrified ducks! :-)
Let's see.... MV content..... A neighboring county's mutual aid
(I think things were really slow for them that night!) showed up,
and it was an M37 with a brush truck rig set up in the cargo bed.
Painted "Fire Dept. Red", of course! ;-)
Jerry
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