I realized last night there was still some liquid left in the tanks.
I bled that off, and left the valves open overnight.

Note: Don't get that liquid on your skin. Not so much for the
obvious frost bite hazards, but because of that nasty ethyl mercaptain
odorant that is in the gas that will absorb into your skin. My wife
was not happy with me last night. My hands still wreak.

This morning, I chained the tank to a solid post, and used a load
binder to tighten it up so it wouldn't move. I lucked out in that I
managed to find a combination of links that allowed me to get the
chain very tight, but not to the point of crushing the tank.

I closed the valves, and used a propane torch to heat the bung until
it was too hot to touch.

I leaned on the handle of a 24" pipe wrench, and the valves backed out
easily. (they are RIGHT handed, by the way)

There is a thread seal dope on the threads that hardens as it cures.
As many people have told me, this makes the valves virtually
impossible to remove. Heat softens the dope, and makes it easy to
remove the valves.

Now, before I get flamed for applying heat to the tanks, let me
explain some logic here.

First, although the tanks were full of LP vapor, there was no liquid,
and there was no pressure in the tanks.

Second, the valves were closed, so no gas was escaping and available
to ignite.

Third, the inside of the tank contained 100% LP vapor. This is not
explosive. The explosive limits for LP gas is between 1% and 10% in
air. Had a fracture occurred, the flame would not have burned into
the tank. The flame would have only occurred where the escaping gas
was mixing with air.

I got advice from people saying to pressurize the tank with air, and
bleed it off a couple of times. This could have easily left me with
an explosive mixture inside the tank. Leaving it full of 100% LP
vapor was MUCH safer.

Fourth, this was a 100 pound LP tank. Heating the bung is not going
to heat the gas inside to any significant amount, and certainly not
enough to risk a pressure explosion. In fact, when the valve was
removed, there was barely any hiss of gas escaping.

Dave

Serial # 19781010 wrote in message . ..
I realized last night there was still some liquid left in the tanks.
I bled that off, and left the valves open overnight.


You were lucky
Your arguement about it being 100% vapor sucks wind after leaving the
valves open overnight.
Next time before we read about pieces of you being found elsewhere
quit screwing around and fill the tanks with water.

Better you than me, I already went through having a pressurized
-non-flamable container go off on me, and certainly would not want to
even consider a container that held propane no matter how small of
ratio of gas to air it had. Its certainly not worth my life or limb to
take such a chance.

I have taken them out before and have never used heat.
Visit my website: http://www.frugalmachinist.com
Opinions expressed are those of my wifes,
I had no input whatsoever.
Remove "nospam" from email addy.

On 26 Nov 2003 15:07:50 -0800, (Beecrofter) wrote:

Serial # 19781010 wrote in message . ..
I realized last night there was still some liquid left in the tanks.
I bled that off, and left the valves open overnight.


You were lucky
Your arguement about it being 100% vapor sucks wind after leaving the
valves open overnight.
Next time before we read about pieces of you being found elsewhere
quit screwing around and fill the tanks with water.

Luck had nothing to do with it.

First, LP gas is more dense than air. It isn't going to leave the tank
of it's own free will.

Second, even if some air had managed to get drawn back into the tank,
it certainly wouldn't achieve the 90% air required to make the mixture
explosive.

Third, how would you fill a propane tank with water with the valve
still in it?

Dave

On Thu, 27 Nov 2003 02:13:31 GMT, (Roy) wrote:

Better you than me, I already went through having a pressurized
-non-flamable container go off on me, and certainly would not want to
even consider a container that held propane no matter how small of
ratio of gas to air it had. Its certainly not worth my life or limb to
take such a chance.

I have taken them out before and have never used heat.
Visit my website: http://www.frugalmachinist.com
Opinions expressed are those of my wifes,
I had no input whatsoever.
Remove "nospam" from email addy.


How can you compare the danger of a pressurized container to a
non-pressurized container?

How dangerous would a non-pressurized container be, if it's contents
were not explosive?

Dave

Hey Beecrofter,

And leave the valve closed? Now that IS scary. The steam pressure
will kill him long before there is enough heat applied to loosen core.
Or the core loosening will cause the steam to blow it out!

Take care.

Brian Lawson,
Bothwell, Ontario.
XXXXXXXXXXXXXXXXXXXXX
On 26 Nov 2003 15:07:50 -0800, (Beecrofter) wrote:

Serial # 19781010 wrote in message . ..
I realized last night there was still some liquid left in the tanks.
I bled that off, and left the valves open overnight.


You were lucky
Your arguement about it being 100% vapor sucks wind after leaving the
valves open overnight.
Next time before we read about pieces of you being found elsewhere
quit screwing around and fill the tanks with water.

Just make sure you wash it out with Chlorine (Chlorox) to kill most of
the ethel mercaptan (stink) or you'll smell it for a very long time.


Also ethel settles out , there could be a pool in the bottom of an old
tank. It should be dumped before washing. Don't spill it or you could be
sorry.





--

Mark

N.E. Ohio


Never argue with a fool, a bystander can't tell you apart. (S. Clemens,
A.K.A. Mark Twain)

When in doubt hit the throttle. It may not help but it sure ends the
suspense. (Gaz, r.moto)

David A. Webb writes:

First, LP gas is more dense than air. It isn't going to leave the tank
of it's own free will.

You need to learn about diffusion.

On Thu, 27 Nov 2003 06:48:49 GMT, Mark
wrote:


Just make sure you wash it out with Chlorine (Chlorox) to kill most of
the ethel mercaptan (stink) or you'll smell it for a very long time.


Also ethel settles out , there could be a pool in the bottom of an old
tank. It should be dumped before washing. Don't spill it or you could be
sorry.


I turned the tanks upside down and vented off the last bit of liquid
LP... and got the stink all over myself in the process.

So... bleach will kill the odor?

Dave

On Thu, 27 Nov 2003 03:42:08 -0600, Richard J Kinch
wrote:

David A. Webb writes:

First, LP gas is more dense than air. It isn't going to leave the tank
of it's own free will.

You need to learn about diffusion.


Okay, I'll concede that if I left the tank valve open long enough, air
would eventually replace ALL of the gas through diffusion. Between
now and that point in time, there would be a point where the mixture
would be explosive. However, the passageway through the valve is
pretty small, and as I stated before , LP vapor is heavier than air.
With the tank all but sealed, and no real movement of the vapor inside
the tank, the diffusion would even slower than if something was
stirring up the gas inside. Overall, the diffusion would be a very
slow process.

I will also concede that based on this, odds are the gas inside the
tank wasn't 100% LP vapor as argued by a previous post. So was it
99.9%? 95%? As stated, the LP vapor has to get down to 10% before it
is explosive.

So in reality, how long would it take for air to diffuse into the tank
through the tiny valve opening, and replace 90% of the LP vapor?

Maybe in my lifetime, but certainly not overnight.

Dave

"David A. Webb" wrote:
...
So... bleach will kill the odor?

From a previous post of mine:
"I poured in about a cup of bleach, sloshed it around, let it sit,
sloshed
a few more times. After about 24 hr., I drained the bleach, rinsed with
a little water and filled with air. The air was totally odor free.
Well, it smelled a little, more like paint thinner than anything.

Note - I did this with the valve on, it would be easier with it off, but
probably not worth the effort."

On Thu, 27 Nov 2003 14:04:21 GMT, David A. Webb
wrote:

===On Thu, 27 Nov 2003 03:42:08 -0600, Richard J Kinch
wrote:
===
===David A. Webb writes:
===
=== First, LP gas is more dense than air. It isn't going to leave the tank
=== of it's own free will.
===
===You need to learn about diffusion.
===
===
===Okay, I'll concede that if I left the tank valve open long enough, air
===would eventually replace ALL of the gas through diffusion. Between
===now and that point in time, there would be a point where the mixture
===would be explosive. However, the passageway through the valve is
===pretty small, and as I stated before , LP vapor is heavier than air.
===With the tank all but sealed, and no real movement of the vapor inside
===the tank, the diffusion would even slower than if something was
===stirring up the gas inside. Overall, the diffusion would be a very
===slow process.
===
===I will also concede that based on this, odds are the gas inside the
===tank wasn't 100% LP vapor as argued by a previous post. So was it
===99.9%? 95%? As stated, the LP vapor has to get down to 10% before it
===is explosive.
===
===So in reality, how long would it take for air to diffuse into the tank
===through the tiny valve opening, and replace 90% of the LP vapor?
===
===Maybe in my lifetime, but certainly not overnight.
===
===Dave
===

How exactly did you determine it was at the concentration level you
stated?
Visit my website: http://www.frugalmachinist.com
Opinions expressed are those of my wifes,
I had no input whatsoever.
Remove "nospam" from email addy.

On Thu, 27 Nov 2003 16:23:29 GMT, (Roy) wrote:


How exactly did you determine it was at the concentration level you
stated?
Visit my website: http://www.frugalmachinist.com
Opinions expressed are those of my wifes,
I had no input whatsoever.
Remove "nospam" from email addy.

Which concentration level?
I initially stated that it was 100% LP vapor.

Then someone argued that because the valve was left open overnight,
it couldn't have been 100% LP vapor. So I conceeded that the LP vapor
concentration in the tank might have been slightly less than 100%, but
not much. Regardless of what it actually was, there was no way it
could have been down to the explosive range.

My initial statement was based on the fact that there was liquid LP
(I know it is redundant) and any tiny bit of air that might have been
in the tank with the liquid would have been purged when I vented the
tanks.

Once the liquid was evaporated, and the pressure inside the tank
dropped to zero, it is safe to assume the only thing left in the tank
is LP vapor.

Had there not been any liquified gas in the tank, I wouldn't have had
any way of knowing what kind of mixture was in the tank, and I
wouldn't have attempted to heat the bung before doing something to
make the situation safer.

Dave

David A. Webb wrote:


Also ethel settles out ,

I turned the tanks upside down and vented off the last bit of liquid
LP... and got the stink all over myself in the process.

So... bleach will kill the odor?



"Kill" is too optimistic of word.

It will decrease the stink substantially under best of circumstances.


HTH




--

Mark

N.E. Ohio


Never argue with a fool, a bystander can't tell you apart. (S. Clemens,
A.K.A. Mark Twain)

When in doubt hit the throttle. It may not help but it sure ends the
suspense. (Gaz, r.moto)

David A. Webb wrote:


I turned the tanks upside down and vented off the last bit of liquid
LP... and got the stink all over myself in the process.


Glad you did this. Ethel M will be mostly dissolved if there is liquid.

So turning it upside down and blowing off the last of the propane was
the best you could do to get rid of the mercaptan.

No fireball, your still alive and unburned, Cool.

I would have found a fitting to plumb it into a flex pipe and then piped
it into a piece of black pipe and had some Fun. Would freak out the
Neighbors.


Don't try this at home, I'm a trained Professional ( Woof! ).



Turning the tank upside down and blowing it off was the best thing you
could do to get rid of the stink.






--
--

Mark

N.E. Ohio


Never argue with a fool, a bystander can't tell you apart. (S. Clemens,
A.K.A. Mark Twain)

When in doubt hit the throttle. It may not help but it sure ends the
suspense. (Gaz, r.moto)

On Wed, 26 Nov 2003 08:53:21 -0600, Serial # 19781010
wrote:

Snip

I closed the valves, and used a propane torch to heat the bung until
it was too hot to touch.

Snip

Now, before I get flamed for applying heat to the tanks, let me
explain some logic here.

First, although the tanks were full of LP vapor, there was no liquid,
and there was no pressure in the tanks.

Second, the valves were closed, so no gas was escaping and available
to ignite.

Third, the inside of the tank contained 100% LP vapor. This is not
explosive. The explosive limits for LP gas is between 1% and 10% in
air. Had a fracture occurred, the flame would not have burned into
the tank. The flame would have only occurred where the escaping gas
was mixing with air.

I got advice from people saying to pressurize the tank with air, and
bleed it off a couple of times. This could have easily left me with
an explosive mixture inside the tank. Leaving it full of 100% LP
vapor was MUCH safer.

Fourth, this was a 100 pound LP tank. Heating the bung is not going
to heat the gas inside to any significant amount, and certainly not
enough to risk a pressure explosion. In fact, when the valve was
removed, there was barely any hiss of gas escaping.

Dave

When I worked for the gas company, we had a foreman who would fix gas
leaks in the pipeline by arc-welding them while the gas was escaping.

I don't know if OSHA would allow such a thing, any more.

Orrin

Serial # 19781010 wrote:

I realized last night there was still some liquid left in the tanks.
I bled that off, and left the valves open overnight.

Note: Don't get that liquid on your skin. Not so much for the
obvious frost bite hazards, but because of that nasty ethyl mercaptain
odorant that is in the gas that will absorb into your skin. My wife
was not happy with me last night. My hands still wreak.

This morning, I chained the tank to a solid post, and used a load
binder to tighten it up so it wouldn't move. I lucked out in that I
managed to find a combination of links that allowed me to get the
chain very tight, but not to the point of crushing the tank.

I closed the valves, and used a propane torch to heat the bung until
it was too hot to touch.

I leaned on the handle of a 24" pipe wrench, and the valves backed out
easily. (they are RIGHT handed, by the way)

There is a thread seal dope on the threads that hardens as it cures.
As many people have told me, this makes the valves virtually
impossible to remove. Heat softens the dope, and makes it easy to
remove the valves.

Now, before I get flamed for applying heat to the tanks, let me
explain some logic here.

First, although the tanks were full of LP vapor, there was no liquid,
and there was no pressure in the tanks.

Second, the valves were closed, so no gas was escaping and available
to ignite.

Third, the inside of the tank contained 100% LP vapor. This is not
explosive. The explosive limits for LP gas is between 1% and 10% in
air. Had a fracture occurred, the flame would not have burned into
the tank. The flame would have only occurred where the escaping gas
was mixing with air.

I got advice from people saying to pressurize the tank with air, and
bleed it off a couple of times. This could have easily left me with
an explosive mixture inside the tank. Leaving it full of 100% LP
vapor was MUCH safer.

Fourth, this was a 100 pound LP tank. Heating the bung is not going
to heat the gas inside to any significant amount, and certainly not
enough to risk a pressure explosion. In fact, when the valve was
removed, there was barely any hiss of gas escaping.

Dave
how about the guys each year that take an old 55 gal.drum at work and
think they gonna cut the top off to make a nice trash can/burner with it
and it blows up on them..... too close to an old propane tank for me to
mess with.... i would just leave the tank alone and go with something
else that cost a few bucks to maybe save me from flying in the air when
it blows..... i know it is not suppose to blow, but i remember seeing a
PVC pipe that was used for water on an a/c unit in an office building
that expaned from its normal 3 inch size to about 6 inches and exploded
during the night and left this 4 story bank building full of water all
the way down to the 1st floor which was the bank office.. about 4 inches
of water on the floor...... the manager was on the phone talking to one
of the officers and was telling him what happened.....about 10:00PM....
then i guess the officer told the manager that this does not happen....
the manager was hollering into the phone that i know it does not
happen, but i am looking at it....... needless to say they were told to
tell the employees to come to work in blue jeans the next morning....

In article ,
Mark wrote:

David A. Webb wrote:


Also ethel settles out ,

I turned the tanks upside down and vented off the last bit of liquid
LP... and got the stink all over myself in the process.

So... bleach will kill the odor?



"Kill" is too optimistic of word.

It will decrease the stink substantially under best of circumstances.

To get the stink off of YOU (& your clothes) light a smouldering smoking
fire in your gravel driveway or yard and walk thru the smoke. It will
kill the smell good enough for your wife's nose.

--
free men own guns - slaves don't
www.geocities.com/CapitolHill/5357/

In article ,
David A. Webb wrote:

My initial statement was based on the fact that there was liquid LP
(I know it is redundant) and any tiny bit of air that might have been
in the tank with the liquid would have been purged when I vented the
tanks.

Once the liquid was evaporated, and the pressure inside the tank
dropped to zero, it is safe to assume the only thing left in the tank
is LP vapor.

If you let the LP vapor bubble out thru a jug of water, if there is any
suck back it will be water.

--
free men own guns - slaves don't
www.geocities.com/CapitolHill/5357/

On Fri, 28 Nov 2003 06:36:26 GMT, Mark
wrote:



David A. Webb wrote:


Also ethel settles out ,

I turned the tanks upside down and vented off the last bit of liquid
LP... and got the stink all over myself in the process.

So... bleach will kill the odor?



"Kill" is too optimistic of word.

It will decrease the stink substantially under best of circumstances.


HTH
I find that about ten air purges over a month does a fair job of
getting most of the mercaptan out.
Gerry :-)}
London, Canada

On Fri, 28 Nov 2003 21:34:12 GMT, jim wrote:



how about the guys each year that take an old 55 gal.drum at work and
think they gonna cut the top off to make a nice trash can/burner with it
and it blows up on them..... too close to an old propane tank for me to
mess with.... i would just leave the tank alone and go with something
else that cost a few bucks to maybe save me from flying in the air when
it blows..... i know it is not suppose to blow,

This is one place where the cold chisel is far superior to the gas
axe.
Gerry :-)}
London, Canada

Brian Lawson wrote in message . ..
Hey Beecrofter,

And leave the valve closed? Now that IS scary. The steam pressure
will kill him long before there is enough heat applied to loosen core.
Or the core loosening will cause the steam to blow it out!

Take care.

Brian Lawson,
Bothwell, Ontario.

Only if we are skipping dangerous and moving directly to stupid!

On Thu, 27 Nov 2003 14:04:21 GMT, David A. Webb
wrote:

On Thu, 27 Nov 2003 03:42:08 -0600, Richard J Kinch
wrote:

David A. Webb writes:
.............................. snip..................................

I will also concede that based on this, odds are the gas inside the
tank wasn't 100% LP vapor as argued by a previous post. So was it
99.9%? 95%? As stated, the LP vapor has to get down to 10% before it
is explosive.



............................very, very wrong..........................


Dave. I am not trying to be sarcastic but you really need to educate
yourself about LPG before you kill your self. Google up the word
"BLEVE" and I think you will see some of your premises are not true. I
have worked in a big chemical refinery for the last 30 years, and deal
with huge quantities of propanes, butanes, methanes,ect. and can
assure you that I know what I am talking about. I have seen bleves and
and have known people who were killed when they went up. I have seen
little things as you have done become really bad, really quick. Yes,
hot taps are made, but these are done under special conditions that
are too lengthy to describe here, and with trained personel. Knowing
what I know about LPGs I wouldn't have done what you did for a million
dollars. I would have gotten a very big wrench, like the propane
companies do, and taken the valve off. Ask your local fire chief as
to his opinion, or better yet , email the Texas A & M fire school and
query the chief instructor. Stay safe..........................

Kent

On Mon, 01 Dec 2003 15:11:51 GMT, Kent Fowler
wrote:

Dave. I am not trying to be sarcastic but you really need to educate
yourself about LPG before you kill your self. Google up the word
"BLEVE" and I think you will see some of your premises are not true. I
have worked in a big chemical refinery for the last 30 years, and deal
with huge quantities of propanes, butanes, methanes,ect. and can
assure you that I know what I am talking about. I have seen bleves and
and have known people who were killed when they went up. I have seen
little things as you have done become really bad, really quick. Yes,
hot taps are made, but these are done under special conditions that
are too lengthy to describe here, and with trained personel. Knowing
what I know about LPGs I wouldn't have done what you did for a million
dollars. I would have gotten a very big wrench, like the propane
companies do, and taken the valve off. Ask your local fire chief as
to his opinion, or better yet , email the Texas A & M fire school and
query the chief instructor. Stay safe..........................

Kent


Kent,

BLEVE... Boiling Liquid Expanding Vapour Explosion

Do you see how this fails to apply to my situation?

I said I removed ALL of the liquid first, so there is no "BL"

Second, The internal pressure of the tank was at atmospheric pressure.
So there is no "EVE".

SO I am not at risk for BLEVE.

And before I would ask my local fire chief, I am reminded of the chief
my Dad worked for 20 years ago, who talked about how dangerous it was
to hydro-test their SCBA tanks. According to him, tanks were tested
under water to help contain an explosion if the tanks failed. Super
dangerous because under that pressure, if a tank burst, shrapnel would
kill everyone if it wasn't for the tank of water used to slow down the
explosion. Duh.

So, as far as I'm concerned, being a fire chief doesn't make a person
the final authority on risks of tank explosions.

Dave

C'mon, people, it's a done deal.

He got lucky.

He did it right.

He should have been killed.

Perhaps all of these are true. Perhaps none of them are. That isn't
important. What is important is that he got it done, and, regardless of
how or why, he got it done without getting hemself damaged or dead in
the process.

No amount of Monday-morning quarterbacking changes that fact.

Sure, it was insanely dangerous. Sure, he could have blown himself to
hell. He might have even taken half the neighborhood with him in the
process.

BUT HE DIDN'T.

Task is completed, results satisfy the person who wanted it done. Can't
we move on to something a little more constructive than fancily phrased
"You were a stupid fool that got lucky once, here's what you should have
done, dummy"???

Think about it, people - the horse is dead, the crows have picked it
down to clean bones, and even the bad smell is gone.

Let it rest already!

--
Don Bruder - --- Preferred Email - SpamAssassinated.
Hate SPAM? See http://www.spamassassin.org for some seriously great info.
I will choose a path that's clear: I will choose Free Will! - N. Peart
Fly trap info pages: http://www.sonic.net/~dakidd/Horses/FlyTrap/index.html

On Mon, 01 Dec 2003 21:25:32 GMT, Don Bruder wrote:

Sure, it was insanely dangerous. Sure, he could have blown himself to
hell. He might have even taken half the neighborhood with him in the
process.

BUT HE DIDN'T.

Task is completed, results satisfy the person who wanted it done. Can't
we move on to something a little more constructive than fancily phrased
"You were a stupid fool that got lucky once, here's what you should have
done, dummy"???


Funny, you are doing EXACTLY what you are criticizing others for.

I posted only to explain how I did it, and why I consider it safe.

I encourage people to criticize, and give reasons why they consider it
dangerous. As far as I can tell, many people agree it was relatively
safe. And those that said it was dangerous didn't really support
their opinion.

If you think it was so terribly dangerous, please explain why.

Dave

David, I must say you do hold your own! Loved that fire chief story .. - GWE

David A. Webb wrote:

On Mon, 01 Dec 2003 15:11:51 GMT, Kent Fowler
wrote:


Dave. I am not trying to be sarcastic but you really need to educate
yourself about LPG before you kill your self. Google up the word
"BLEVE" and I think you will see some of your premises are not true. I
have worked in a big chemical refinery for the last 30 years, and deal
with huge quantities of propanes, butanes, methanes,ect. and can
assure you that I know what I am talking about. I have seen bleves and
and have known people who were killed when they went up. I have seen
little things as you have done become really bad, really quick. Yes,
hot taps are made, but these are done under special conditions that
are too lengthy to describe here, and with trained personel. Knowing
what I know about LPGs I wouldn't have done what you did for a million
dollars. I would have gotten a very big wrench, like the propane
companies do, and taken the valve off. Ask your local fire chief as
to his opinion, or better yet , email the Texas A & M fire school and
query the chief instructor. Stay safe..........................

Kent


Kent,

BLEVE... Boiling Liquid Expanding Vapour Explosion

Do you see how this fails to apply to my situation?

I said I removed ALL of the liquid first, so there is no "BL"

Second, The internal pressure of the tank was at atmospheric pressure.
So there is no "EVE".

SO I am not at risk for BLEVE.

And before I would ask my local fire chief, I am reminded of the chief
my Dad worked for 20 years ago, who talked about how dangerous it was
to hydro-test their SCBA tanks. According to him, tanks were tested
under water to help contain an explosion if the tanks failed. Super
dangerous because under that pressure, if a tank burst, shrapnel would
kill everyone if it wasn't for the tank of water used to slow down the
explosion. Duh.

So, as far as I'm concerned, being a fire chief doesn't make a person
the final authority on risks of tank explosions.

Dave

On Mon, 01 Dec 2003 13:42:03 -0600, David A. Webb
wrote:



Kent


Kent,

BLEVE... Boiling Liquid Expanding Vapour Explosion

Do you see how this fails to apply to my situation?

I said I removed ALL of the liquid first, so there is no "BL"

Are you sure?

Second, The internal pressure of the tank was at atmospheric pressure.
So there is no "EVE".

And just because the tank was at atmospheric, there
was NO hydrocarbon vapor in it?

SO I am not at risk for BLEVE.

So you hope.

And before I would ask my local fire chief, I am reminded of the chief
my Dad worked for 20 years ago, who talked about how dangerous it was
to hydro-test their SCBA tanks. According to him, tanks were tested
under water to help contain an explosion if the tanks failed. Super
dangerous because under that pressure, if a tank burst, shrapnel would
kill everyone if it wasn't for the tank of water used to slow down the
explosion. Duh.

We are not talking hydrotesting, we are talking
putting heat to a vessel that has hydrocarbons in it

So, as far as I'm concerned, being a fire chief doesn't make a person
the final authority on risks of tank explosions.

Maybe not, but I gave you directions to the people
wrote the book on the subject. But I can see that
nothing is going to change your mind that what you
did is perfectly safe, so I can see I am wasting my
time. Maybe some one else reading this exchange
will learn a little from it

Regards, Kent

Dave

"David A. Webb" wrote:

On Mon, 01 Dec 2003 21:25:32 GMT, Don Bruder wrote:
[more flames about Dave while calling for it to stop]

Funny, you are doing EXACTLY what you are criticizing others for.

Indeed!

I posted only to explain how I did it, and why I consider it safe.
...
If you think it was so terribly dangerous, please explain why.


Good luck. I've posted about my experiences with empty propane tanks
and ALWAYS get a lot of baloney about how dangerous they are without any
explanation, or even anecdotal evidence. There's a common psychological
model at work he If you've always heard that something is true, and
it seems reasonable, then it must be true. In this case, the belief
creates a fear of investigating whether it really is true.

I've been meaning to do the chemistry to show that there simply is not
enough energy from the propane in an empty tank to do any harm. But I
haven't gotten around to it (what else is new?).

Bob

On Mon, 01 Dec 2003 22:53:36 GMT, Kent Fowler
wrote:

I said I removed ALL of the liquid first, so there is no "BL"

Are you sure?

Hmmmm... I had the tank inverted until all of the liquid was purged,
and I then left the valve open all night... yep, pretty sure there is
no liquid left, and hence nothing left to boil. Hence, no "boiling
liquid" part of the BLEVE equation.

Why are you having such difficulty with this?

Second, The internal pressure of the tank was at atmospheric pressure.
So there is no "EVE".

And just because the tank was at atmospheric, there
was NO hydrocarbon vapor in it?

On the contrary, I was hoping there was 100% hydrocarbon vapor in it.

With 100% hydrocarbon vapor, there is zero risk of explosion. Propane
will not burn or explode (as in a fuel/air explosion) without the
oxygen in air.

SO I am not at risk for BLEVE.

So you hope.

Hope has nothing to do with it.
Explain why you think there is risk?

And before I would ask my local fire chief, I am reminded of the chief
my Dad worked for 20 years ago, who talked about how dangerous it was
to hydro-test their SCBA tanks. According to him, tanks were tested
under water to help contain an explosion if the tanks failed. Super
dangerous because under that pressure, if a tank burst, shrapnel would
kill everyone if it wasn't for the tank of water used to slow down the
explosion. Duh.

We are not talking hydrotesting, we are talking
putting heat to a vessel that has hydrocarbons in it

True, I am talking about putting heat to a vessel that has
hydrocarbons in it. However, YOU were talking about putting heat to a
vessel which has a LIQUID in it. That changes everything.
Lets stay on the same page, shall we.

The vapor inside my tank isn't going to spontaneously ignite.
It can't, without oxygen. So again, where is the risk?

So, as far as I'm concerned, being a fire chief doesn't make a person
the final authority on risks of tank explosions.

Maybe not, but I gave you directions to the people
wrote the book on the subject. But I can see that
nothing is going to change your mind that what you
did is perfectly safe, so I can see I am wasting my
time. Maybe some one else reading this exchange
will learn a little from it

I know that most firemen are extremely over reactive to people asking
questions about fire. Their passion sometimes gets in their way of
logic. I don't know any firemen with a degree in physics or
chemistry, probably because anyone with a degree in physics or
chemistry would be in a different career. Maybe forensics
investigator, or something of the sort, but not fire chief.

Not to mention the fact that for liability reasons alone, no fire
chief is going to admit that what I did was safe. For that matter, I
never claimed it was safe (again, for liability reasons). But if you
can tell me where the risk is, I'd love to hear it.

Dave

On Tue, 02 Dec 2003 00:05:26 GMT, David A. Webb
wrote:

On Mon, 01 Dec 2003 22:53:36 GMT, Kent Fowler
wrote:

I said I removed ALL of the liquid first, so there is no "BL"

Are you sure?

Hmmmm... I had the tank inverted until all of the liquid was purged,
and I then left the valve open all night... yep, pretty sure there is
no liquid left, and hence nothing left to boil. Hence, no "boiling
liquid" part of the BLEVE equation.

Why are you having such difficulty with this?

The reason I pointed you toward bleve is to see the result of a
vapor explosion.

Second, The internal pressure of the tank was at atmospheric pressure.
So there is no "EVE".

And just because the tank was at atmospheric, there
was NO hydrocarbon vapor in it?

On the contrary, I was hoping there was 100% hydrocarbon vapor in it.

With 100% hydrocarbon vapor, there is zero risk of explosion. Propane
will not burn or explode (as in a fuel/air explosion) without the
oxygen in air.

And what happens if you just happen to burn a little bitty
hole in the tank with your torch?





True, I am talking about putting heat to a vessel that has
hydrocarbons in it. However, YOU were talking about putting heat to a
vessel which has a LIQUID in it. That changes everything.
Lets stay on the same page, shall we.

Changes nothing. You still have the vapor and the vapor is
what is going to ignite first if you happen to put a hole in that thin
tank with a torch.
The vapor inside my tank isn't going to spontaneously ignite.
It can't, without oxygen. So again, where is the risk

The little bitty hole and a heat source such as
your torch will sure do it.




I know that most firemen are extremely over reactive to people asking
questions about fire. Their passion sometimes gets in their way of
logic. I don't know any firemen with a degree in physics or
chemistry, probably because anyone with a degree in physics or
chemistry would be in a different career.

I know lots of them. Degreed chemical and
mechanical engineers compose part of our plants' fire crews and other
refineries in this area. Let's not get elitist here..

Not to mention the fact that for liability reasons alone, no fire
chief is going to admit that what I did was safe. For that matter, I
never claimed it was safe (again, for liability reasons). But if you
can tell me where the risk is, I'd love to hear it.

The torch and the vapor is the risk

Regards, Kent

Bob Engelhardt writes:

I've been meaning to do the chemistry to show that there simply is not
enough energy from the propane in an empty tank to do any harm. But I
haven't gotten around to it (what else is new?).

Yeah, do that chemistry. You essentially have 5 gallons of steam at, what,
3000 deg F? Fair bit of pressure, that, and too quick for the overpressure
device to respond.

Kent Fowler wrote:
...
And what happens if you just happen to burn a little bitty
hole in the tank with your torch?

You get a little bitty amount of propane oozing out (it's not under any
pressure) and burning _outside_ the tank (remember there's NO AIR in the
tank).

...You still have the vapor and the vapor is what is going to ignite first if you
happen to put a hole in that thin tank with a torch.

Wrong - 1. vapor won't ignite without oxygen, 2. There's nothing "thin"
about a 100# tank.

Dave:
The vapor inside my tank isn't going to spontaneously ignite.
It can't, without oxygen. So again, where is the risk

The little bitty hole and a heat source such as
your torch will sure do it.


Braaahh! Wrong again! A little bitty hole will not introduce air into
the tank. Using an OA torch to cut a tank can introduce oxygen
depending upon the mix, but Dave was using a propane torch - there's no
way that's going to put a hole, "little bitty" or otherwise, in the
tank.

Bob

On Tue, 02 Dec 2003 00:30:55 GMT, Kent Fowler
wrote:

The reason I pointed you toward bleve is to see the result of a
vapor explosion.

As I said before, you can't have a vapor explosion without a proper
fuel/air mixture. The gas inside the tank is far from explosive,
hence a vapor explosion is far from possible.

And what happens if you just happen to burn a little bitty
hole in the tank with your torch?

Okay, for the sake of argument, lets assume for a second that my
Bernz-O-Matic propane torch could somehow burn a hole in the propane
tank. Now I have a spot where gas could exit, or flame could enter.

We are right back to where I stated the fact that 100% propane gas is
not explosive. Heck, it isn't even flammable if there is no oxygen
present. If the flame tried to travel inside the tank, it would
extinguish as soon as it ran out of oxygen. The smaller the hole, the
faster this would occur. The flame would never reach the inside of
the tank, because there is no oxygen to support combustion.

Since I am very slightly heating the tank, it is more likely that some
of the gas would be forced out of this pinhole. If it caught on fire,
it would burn. But with very little pressure and gas flow, it would
be pretty uneventful.

If it was a pinhole, the flow of gas *could* be pretty fast coming
out of the hole, in which case it is unlikely the gas could even
ignite. Ever try to light a propane torch with too much gas flow?
Can't do it.

The vapor inside my tank isn't going to spontaneously ignite.
It can't, without oxygen. So again, where is the risk

The little bitty hole and a heat source such as
your torch will sure do it.

Do you honestly think a tiny hole in the tank is going to instantly
allow enough air into the tank to replace 90% of the internal volume?
That is what would have to happen in order to have the gas inside
explode.

Or, are you concerned with the tiny hole allowing gas to escape and
catch fire? It isn't going to be much gas, since I said there was no
pressure in the tank.

The torch and the vapor is the risk


Are you one of these people who believe lighting hair spray on fire as
it exits a can is dangerous, because the flame can travel through the
nozzle, and inside the can, causing the contents to explode?
You have the pinhole (nozzle being depressed), you have the fuel, you
have the fire..... but the flame can't travel into the nozzle.

Lighting hair spray on fire as it exits the can is dangerous for many
reasons, but not that one.

Dave

Our local junk-yard cut up the old PL tanks everyday... They take a
hammer and bust off the old valve and light the escaping gas and start
the cutting immediately... So far no problems... I watched them do
this... I would not like to do it...

Richard J Kinch wrote:
Yeah, do that chemistry. You essentially have 5 gallons of steam at, what,
3000 deg F? Fair bit of pressure, that, and too quick for the overpressure
device to respond.

Oh! You did the chemistry! Great! Care to share it with us?

On Mon, 01 Dec 2003 20:27:21 -0500, Bob Engelhardt
wrote:

Kent Fowler wrote:
...
And what happens if you just happen to burn a little bitty
hole in the tank with your torch?

You get a little bitty amount of propane oozing out (it's not under any
pressure) and burning _outside_ the tank (remember there's NO AIR in the
tank).

...You still have the vapor and the vapor is what is going to ignite first if you
happen to put a hole in that thin tank with a torch.

Wrong - 1. vapor won't ignite without oxygen, 2. There's nothing "thin"
about a 100# tank.

How do you know there was not O2 in the tank? Remember, he
said he left the valve open over nite, I believe. Could have gotten
enough air to take it out of the rich range into the flamable limit
range. You are " assuming" no air had gotten in there. So is Dave.Was
the mixture checked with an flammable limits meter? No. So you don' t
know, Dave doesn't know and I don't know. Therefore I'm not going to
put any flame on it cause I don't know. I know now,what you guys are
going to do. BTW, you would be suprised how thin those tanks are.

Dave:
The vapor inside my tank isn't going to spontaneously ignite.
It can't, without oxygen. So again, where is the risk

The little bitty hole and a heat source such as
your torch will sure do it.


Braaahh! Wrong again! A little bitty hole will not introduce air into
the tank. Using an OA torch to cut a tank can introduce oxygen
depending upon the mix, but Dave was using a propane torch - there's no
way that's going to put a hole, "little bitty" or otherwise, in the
tank.
Braaaah all you want, stranger things have happened. That's why they
call them " accidents". I see you guys like to push your luck. , You
know for sure there was no O2 in there, don't you. And you know for
sure Dave didn't have a mapp gas cylinder instead of propane. Hell,
the next time Dave wants to put a torch to a cylinder, you might stand
next to him. Smart guys like you fellows surely can't be wrong.

Regards, Kent

On Tue, 02 Dec 2003 01:55:24 GMT, David A. Webb
wrote:

On Tue, 02 Dec 2003 00:30:55 GMT, Kent Fowler
wrote:

The reason I pointed you toward bleve is to see the result of a
vapor explosion.

As I said before, you can't have a vapor explosion without a proper
fuel/air mixture. The gas inside the tank is far from explosive,
hence a vapor explosion is far from possible.

And what happens if you just happen to burn a little bitty
hole in the tank with your torch?

Okay, for the sake of argument, lets assume for a second that my
Bernz-O-Matic propane torch could somehow burn a hole in the propane
tank. Now I have a spot where gas could exit, or flame could enter.

We are right back to where I stated the fact that 100% propane gas is
not explosive. Heck, it isn't even flammable if there is no oxygen
present. If the flame tried to travel inside the tank, it would
extinguish as soon as it ran out of oxygen. The smaller the hole, the
faster this would occur. The flame would never reach the inside of
the tank, because there is no oxygen to support combustion.

Since I am very slightly heating the tank, it is more likely that some
of the gas would be forced out of this pinhole. If it caught on fire,
it would burn. But with very little pressure and gas flow, it would
be pretty uneventful.

If it was a pinhole, the flow of gas *could* be pretty fast coming
out of the hole, in which case it is unlikely the gas could even
ignite. Ever try to light a propane torch with too much gas flow?
Can't do it.

The vapor inside my tank isn't going to spontaneously ignite.
It can't, without oxygen. So again, where is the risk

The little bitty hole and a heat source such as
your torch will sure do it.

Do you honestly think a tiny hole in the tank is going to instantly
allow enough air into the tank to replace 90% of the internal volume?
That is what would have to happen in order to have the gas inside
explode.

Or, are you concerned with the tiny hole allowing gas to escape and
catch fire? It isn't going to be much gas, since I said there was no
pressure in the tank.

The torch and the vapor is the risk


Are you one of these people who believe lighting hair spray on fire as
it exits a can is dangerous, because the flame can travel through the
nozzle, and inside the can, causing the contents to explode?
You have the pinhole (nozzle being depressed), you have the fuel, you
have the fire..... but the flame can't travel into the nozzle.

Lighting hair spray on fire as it exits the can is dangerous for many
reasons, but not that one.

Dave
Dave, let me put it this way and then I am ending my part in this
thread. . I hate to see folks get hurt/burned/killed by taking
chances they did not have have to. I have known people who were maimed
or killed by doing just that. And in my opinion, you took a pretty
scary chance and I think you were lucky the conditions weren't right
to have an accident. They could have been real easily. As I said, I
would have gotten a big wrench or if push came to shove and I could
not have taken the valve out. I would have filled the tank with water
through the valve to eliminate the vapor space then used the torch. I
wouldn't have stuck even a match to it until that vapor space was
gone. Why take the chance????
As far as the hairspray thing. I'll say this. I work with
hydrocarbon reactions using super high pressures and elevated
temperatures every day. I know the physics. I know the math. I also
know what can happen if one little thing goes wrong.

Regards, Kent

The Has mat manager of a local large county near here is a personal
friend.
He gets full tanks all of the time. Lots of partials.

People move out - can't take them with them so they have to turn them in
somewhere.

Martin
--
Martin Eastburn, Barbara Eastburn
@ home at Lion's Lair with our computer
NRA LOH, NRA Life
NRA Second Amendment Task Force Charter Founder

Hey Kent. I gotta real heart-stopper for 'ya. Earlier today I was
drilling a 'decomissioning' hole in a disposable propane tank (later
to be cut up for use as a small crucible, but that's another story),
well I figured I'd pop two so I can have a little fun with the 1atm
gas left sitting inside.. Grab a straw and a lighter and blow flames!

You'll be interested to know that, no matter how hard I tried to get
oxygen into the bottle, I never got internal combustion.

Another neat trick is taking your air+propane torch set lean, put it
down the neck of an empty milk jug, blast it for 10 seconds (until it's
full of propane), then light it off (use something long BTW). Fwooom!
To add to the enjoyment, you can pick up the jug and then light it off -
rocket propulsion!

No matter what setting, rich nor lean, have I had any faster than a
slow burn. The HDPE jug remains intact, though slightly warm.

BTW... anyone with a propane foundry can try a similar cute trick. Put
some loose leaves in the furnace, turn on the gas, then light it from
the top (I 'spose you could do it from the bottom too).

Tim

--
"That's for the courts to decide." - Homer Simpson
Website @ http://webpages.charter.net/dawill/tmoranwms

"Kent Fowler" wrote in message
...
On Mon, 01 Dec 2003 20:27:21 -0500, Bob Engelhardt
wrote:

Kent Fowler wrote:
...
And what happens if you just happen to burn a little bitty
hole in the tank with your torch?

You get a little bitty amount of propane oozing out (it's not under any
pressure) and burning _outside_ the tank (remember there's NO AIR in the
tank).

...You still have the vapor and the vapor is what is going to ignite
first if you
happen to put a hole in that thin tank with a torch.

Wrong - 1. vapor won't ignite without oxygen, 2. There's nothing "thin"
about a 100# tank.

How do you know there was not O2 in the tank? Remember, he
said he left the valve open over nite, I believe. Could have gotten
enough air to take it out of the rich range into the flamable limit
range. You are " assuming" no air had gotten in there. So is Dave.Was
the mixture checked with an flammable limits meter? No. So you don' t
know, Dave doesn't know and I don't know. Therefore I'm not going to
put any flame on it cause I don't know. I know now,what you guys are
going to do. BTW, you would be suprised how thin those tanks are.

Dave:
The vapor inside my tank isn't going to spontaneously ignite.
It can't, without oxygen. So again, where is the risk

The little bitty hole and a heat source such as
your torch will sure do it.


Braaahh! Wrong again! A little bitty hole will not introduce air into
the tank. Using an OA torch to cut a tank can introduce oxygen
depending upon the mix, but Dave was using a propane torch - there's no
way that's going to put a hole, "little bitty" or otherwise, in the
tank.
Braaaah all you want, stranger things have happened. That's why they
call them " accidents". I see you guys like to push your luck. , You
know for sure there was no O2 in there, don't you. And you know for
sure Dave didn't have a mapp gas cylinder instead of propane. Hell,
the next time Dave wants to put a torch to a cylinder, you might stand
next to him. Smart guys like you fellows surely can't be wrong.

Regards, Kent