Date:         Sat, 25 Jan 1997 23:10:23 -0500 (EST)
Sender:       Vanagon Mailing List <vanagon@vanagon.com>
From:         Gcarlen@aol.com
Subject:      Re: '91 Vanagon engine fire

In a message dated 97-01-25 21:35:31 EST, jscohen@m2.sprynet.com (James
Cohen) writes:

> 
>  >	We were lucky! Had the fire not been visible to the driver, and the
>  >	  key been turned in the ignition, the engine and propane tank would
>  >	  have in all likelyhood exploded.
>  >
>  
>  When my '86 burned up the propane tank did not explode.  The seals blew
and
>  a jet of fire shot out to the drivers side for less than a minute until
all
>  the propane was gone.  The gas tank didn't explode either, the tank melted
>  and the gas leaked out and burned on the ground.  The whole Van (westy)
>  burned for forty-five minutes before the fire dept. got to the scene.
>  
>  I  was suprised that there was no explosions, I guess it ain't like the 
> movies.

As a firefighter, maybe I can shed some light.  When we respond to a car on
fire call, the last thing we are worried about is an explosion from fuel
tanks.  The reason is actually pretty simple.  

Gasoline in liquid form doesn't burn.  The danger is from the vapors that are
given off from the gasoline as the temparture increases rapidly.   Diesel
fuel is extremely safe in liquid form.  If the temperature of the fuel (gas
or diesel) is low, there is little danger of explosion.  If the temp is high
(like summer), the liquid can turn to vapor VERY quickly (as in miliseconds).
 The burn is expansive and so quick that it appears instant (hence an
explosion).  The reason gas tanks don't explode very often is because even if
the fuel gives off vapors and is ignited, there is little vapors to explode.

The propane tank, as you indicated, has a over pressure relieve valve.
 Again, propane has to turn to vapor before it will ignite.  So LP propane
has to expand to create vapors (and generate heat as well).  The
characteristics of Propane igniting in an approved propane tank are rather
complex and would take a long time to explain.  

The biggest threat to a person around a car fire is with the newer cars and
the gas shocks in the bumpers and suspension shock absorbers..  Vanagons
don't have these (at least through 85 anyway).

Gregg Carlen
85 Pierce Fire Engine (on occasion)
85 Westy, 76 Goldwing, 51 Plymouth, 75 Mercedes, 69 Alcort...need more toys!