[TheForge] cutting propane cylinders- fuel-air mixture

[Ron Childers]

Ralph, You are correct that air is pumped into tanks to purge them of fumes,
ie, the air-fuel ratio that would explode. The 1,000 gal tank I mentioned
that exploded was excavated from an abandoned gas station per environmental
regulations.

 It was purged with compressed air, checked with an explosion meter, and
certified safe to transport. It was hauled from Salem Fl to Perry, Fl (about
20 miles) on Friday, and allowed to sit until Monday at which time our
Darwin Award winner cut a hole in the side with an oxy propane torch and the
explosion occurred and nearly killed him.

 Even though it was cool weather the gasoline in the pores of the metal
apparently vaporized enough to make an ignitable fuel-air mixture. These
geniuses were cutting up the old excavated gasoline tanks to sell for scrap
and had no explosion meter- they got away with it for years before the big
bang. An explosion meter would have been cheap insurance.

Ron C 

-----Original Message-----
From: theforge-bounces at mailman.qth.net
[mailto:theforge-bounces at mailman.qth.net] On Behalf Of Ralph Sproul
Sent: Wednesday, March 30, 2005 11:40 AM
To: Sponsored by ABANA
Subject: Re: [TheForge] cutting propane cylinders

Greg, I've talked to many welders that have been doing tank repairs for
years.  They either run an air hose in the tank to up the air ratio to the
point it won't ignite, run CO2 so it won't ignite, and thirdly exhaust gas
to purge the tank.

A few fellows would mention the fill with water thing.......but then when
finding out you don't have to wrestle a full tank by purging the tank - they
have usually gone to the other three methods.   I like the compressed air
hose option the least of the three.......but a good friend that's in his
early 60's has been doing it for 40 years this way(he does however full
drain and let set a week before doing this method).  I find it hard to argue
with success.

Ralph
----- Original Message -----
From: "greg" <wglynn at datasync.com>
To: "Sponsored by ABANA" <theforge at mailman.qth.net>
Sent: Wednesday, March 30, 2005 4:55 AM
Subject: Re: [TheForge] cutting propane cylinders