[TheForge] cutting propane cylinders- fuel-air mixture

[Darrell]

Other than the possible exception of abused acetylene tanks, all of the
horror stories involving exploding tanks involve sheet metal tanks or
barrels. The only propane tank explosions that I have ever heard about
involve tanks with a significant amount of propane in them and a BIG fire.
The flame front on propane is slow enough that what you hear on ignition is
WHOOMP where as acetylene you hear BLAM. With the valve out of a 5 to 10
gallon tank, even with a good fuel/air mix in the tank, all you would get is
a jet engine roar. Of coarse you would NOT want to be in front of the
opening.

Darrell

----- Original Message ----- 
From: "Ralph Sproul" <brhlbsmt at mcttelecom.com>
To: <munlaw2 at hcsmail.com>; "Sponsored by ABANA" <theforge at mailman.qth.net>
Sent: Wednesday, March 30, 2005 10:53 AM
Subject: Re: [TheForge] cutting propane cylinders- fuel-air mixture


> Tanks allowed to sit, sweat the fuel out of the pores of the metal.  This
> purged process with gas must be used during welding or cutting process.
If
> someone let a tank sit for a week and then started cutting - your right,
> they deserve a darwin award.
>
> never tried a meter.   It'd be just my luck the batteries would be dead.
> ----- Original Message -----
> From: "Ron Childers" <munlaw2 at hcsmail.com>
> To: "'Sponsored by ABANA'" <theforge at mailman.qth.net>
> Sent: Wednesday, March 30, 2005 12:30 PM
> Subject: RE: [TheForge] cutting propane cylinders- fuel-air mixture
>
>
> 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
>
>
>
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