Date: Mon, 1 Jul 2002 02:25:08 -0700
Reply-To: warmerwagen@HOTMAIL.COM
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Robert Keezer <warmerwagen@HOTMAIL.COM>
Subject: Re: ES-12 Caution
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This is a matter of perspective. Gasoline, which is ten times more explosive than TNT, remains a liquid when released and it's destructive power is well known. It's been said here and elsewhere before most of us are driving around with tanks full of this high explosive but we think nothing of it.
Air-cooled VW's are the most prone to burning from gasoline leaks though I've see a good number of burnt Eurovans too.
The greatest propane hazard I can think of in our Westfalias is the kitchen stove. All you have to do to turn your Vanagon into a daisy-cutter is leave a stove knob on .Then, either static or lighting a match is all it takes to leave a crater with a pair of shoes at the bottom. There are no safety devices that shut of the stove ,other than a person to turn the gas knob to off.
The Westy propane tank holds about 2.8 gallons of propane. The AC system holds maybe 2-3 lbs of propane- like about as much as three disposables. ( I could be wrong here, it might be less)
In the AC system it's not confined in a tank, but spread out . If it should leak, since it's propane , it's likely you'll smell it. It could burn at a break or loose fitting, hole, etc., but unless there is a fire to ignite it it will most likely harmlessly leak out rather quickly.
If fire occurs, the burn will be like a torch, but not an explosion. A long time a go I once put a near empty disposable propane bottle on a outdoor fire. It heated up and finally exploded.
But it was due to pressure, not ignition.The superheated propane added considerably to the effect, but only after the container opened up did the propane ignite. I tried it again a few years later but a pressure relief valve opened, and a jet of flame was all I got. .
The propane in the tank if heated enough would explode initially from pressure. But the brass hardware might also melt first before this can happen and all that will result it a fireball and maybe no explosion. it depends on the ratio of gas and air in the tank.
Now we come to it- there is air in that there propane tank! The kind of propane explosion that is much more violent is when it is mixed with air, --as in the example of the stove knob left on allowing the cabin to fill with gas. . This kind is the worst - it can completely demolish the vehicle, house , etc.
I saw a house once that was leveled from a gas explosion .Cause was determined to be that someone lit a cigarette.
Nowhere in the AC system is the concentration great enough to present this kind of danger or ES-12 would be prohibited.
Since the ES-12 propane is in a sealed system, without air, it can't burn. Chances are in a serious accident gasoline will be the fuel that ignites.
If ES-12 wasn't safe it wouldn't be legal. Strict laws regulate combustible fuels and where and where they can't be used.
So the question is , where in the AC system is the greatest potential for an explosion? In the condenser? Evaporator? Receiver/drier? Compressor? None of the above.
The greatest risk is from doing some welding near the gasoline filler with the cap off and a less than full tank!
Robert
1982 Westfalia 2.0 Golf lll powered
----- Original Message -----
Wrom: AFXISHJEXXIMQ
Sent: Saturday, June 29, 2002 11:14 AM
To: vanagon@GERRY.VANAGON.COM
Subject: Re: ES-12 Caution
Gary
<I use r-134 which cools marginally and if I thought
es-12 would cool better and I was switching from r-12
I would not worry about the burning issue. >
It's not the burning per se, it's the explosion that is of concern.
< First of all the amount of gas in comparison to the propane you
are already carrying is small. It is in a sealed
system without oxygen. If a leak develops the gas
will dissipate quicky.>
The propane tank is in a specially designed and tested vessel that should
withstand severe impact and pressure rise. The AC system in not designed to
the same DOT/ASME standards - actually not even close. Your right, since
there is no O2 in the system, it won't cause a problem until it leaks out and
mixes with air. For the same reason you wouldn't check your propane tank for
leaks with match.
Small amount is also a relative term How long will 3 lbs of propane last in
your BBQ. What if all of that energy was realsed at once (ie. explosion)?
<If you are going to worry about es-12 you should not
use the propane and for that matter the gas in your
tank which represent a much greater hazard.>
Not so.... see above
These are two totally different types of systems - one designed with all the
appropriate safety measures and one not. Just think about it before betting
yours and some one elses life. Believe me, I wish this stuff were safe, I'd
use it in a heartbeat. Think "works great, blows up".
John
84 WestaruGet more from the Web. FREE MSN Explorer download : http://explorer.msn.com
