LP Tank and Fire Inspection

why not use soapy water? 

Soapy water works just fine, The problem is if you go into the soap
section of most stores they are not selling soap in the chemical
sense of the word. A soap / water solution would be non reactive with

Most ‘Soap’ in stores today is either a soap with moisturizer or a
detergent with or without additives. As usual the problem is the
additives. Just another “green amethyst” example of a perfectly good
name that meant one thing being mangled by the marketing folks and
evil geniuses in the Laboratory.

So my advise is basically the same as Jim’s. Use a oxygen safe leak
detector, or you may find the moisturizing oil in the “soap” reacts
with the oxygen…


Note this may seem strange to non north American readers since the
nomenclature and packaging can differ quite a bit elsewhere.

By the way one thing I should add since people are mentioning putting
tanks of Flammable gas outside and plumbing them into the inside
(Which IMHO is not a bad idea).

While copper is generally safe with natural gas and Propane (I
personally would use black iron pipe except for a short pigtail but
that is me). Copper pipe should not be used to plumb in acetylene, as
it reacts chemically with the gas to make a very nasty chemical which
is a shock sensitive explosive…

Again if one takes the time to study the applicable codes and subject
this is mentioned, but since some people seem to be too busy to do
so, I thought I should mention it

And since I keep saying that one should back their opinions with
facts and if possible a link to the proof thereof from a
governmental or reputable educational institute.

Try http://www.msha.gov/Accident_Prevention/Tips/acetylenegas.htm

PS for the nervous Nellie’s amongst us in the web link they are
referring to gas under pressure in contact with silver, copper and
brass. Once the gas has burnt the problem no longer exists


No fuel gas is “safe” because they are all meant to produce hot
flames, but the degree and kind of danger each presents is unique.
There have been several good safety points made so far in this
conversation but I will add a few I haven’t seen yet.

Acetylene -

First, acetylene is highly combustible compared to other gases. If
acetylene leaks it will combust in a mixture in air of anywhere from
2% to 80% and a static electricity spark is sufficient to ignite this

By comparison, natural gas, propane and other similar gases have a
range of combustibility between 5% to 15%, meaning that in the case
of a leak there is a much lower range in which the leak will combust.
It also takes a hotter spark to ignite these gases.

The point is that a much smaller, by volume, acetylene leak is much
easier to ignite than other gases.

Second, handling the cylinder is much more important with acetylene
than other gases.

Acetylene is naturally unstable, meaning that it will explode
(violent decomposition is usually the term in the safety manuals) if
not handled properly. Improper handling can be as simple as dropping
the cylinder or knocking it over. In the safety literature this is
referred to as “mechanical shock”, i.e. the cylinder is struck or
jarred. While people may be careful when moving and changing
cylinders you still might have butterfingers or just be having a bad
day - dropping an acetylene cylinder can make it a really bad day.

Third, how acetylene is withdrawn from the cylinder can create

Acetylene should never be used at higher than 15 psi pressure
because to do so will cause the gas to “dissociate” from the acetone
in which it is dissolved too quickly and this can lead “violent
decomposition”, an explosion. This is why acetylene regulators have a
red field marked on them, yet I have seen people purposely set their
regulators in this red zone thinking if some pressure is good, more
should be better. And these were trained people who should know
better - the danger is in a novice who is not properly aware of the
unique danger acetylene cylinders represent.

The other thing about using acetylene is that you cannot withdraw
more than 1/7 of the cylinder’s contents per hour or again, “violent
decomposition” occurs. This becomes an issue when using a small
cylinder, say a B-tank and the tank is nearing empty. It becomes
easier to reach the 1/7th limit. The issue is not the volume of gas
in the cylinder but the rate at which it dissociates from the acetone

  • do this too quickly and you have an explosion.

Propane -

People are more comfortable with propane because it is more familiar

  • many use it to heat their homes in areas where there is no natural
    gas service. However, the propane tank is kept some distance from the
    house - nobody puts the propane tank in the basement!

Everyone is familiar with propane being heavier that air such that
leaks will sink and pool, and if there is a flame source like a pilot
light in the hot water heater, it will ignite.

The danger that is less often considered is the amount of energy
stored in a propane cylinder, or an acetylene tank for that matter.
Because propane is liquefied it is easier to put more energy in a
smaller container. Compare a B-tank of acetylene, which holds 59,000
BTUs of energy with a 20 lb propane tank which holds more than
432,000 BTUs - a lot more explosive power in a container about the
same size. To visualize what this means, one BTU is about the same
energy released by burning a single wooden kitchen match so consider
storing 59,000 or 432,000 kitchen matches in your studio and what
would happen if they ignited all at once!

A larger propane cylinder, say a 100 lb cylinder, holds more than
2-million BTUs and the power in this cylinder was demonstrated in
Chicago when such a cylinder exploded in a jeweler’s shop on the 6th
floor of a downtown office building. Nine people were injured, some
seriously, smoke filled the building and the windows were blown out.

Besides the danger of the cylinder itself, if a fire occurs there is
greater danger to responding firemen. In commercial and industrial
buildings fire companies make site visits and pre-plan where gas is
stored so if they respond to a fire they know what to expect. This
isn’t the case in a home studio with a cylinder in the basement -
consider your obligation to the local volunteer fire company.

When a propane cylinder explodes it does so in a manner referred to
as a BLEVE - Boiling Liquid Expanding Vapor Explosion. What happens
is that because propane is in liquid form the heat from a fire causes
it to evaporate in the tank and increase tank pressure. The pressure
rises faster than the relief valve can exhaust the gas and pressure
builds to a point where the cylinder ruptures. The explosion spreads
liquid propane over a wide area which itself then combusts, making
the fire worse. If you are old enough to recall Napalm, the effect is
somewhat similar.

Natural Gas -

Many people connect their torches directly to the city natural gas
line and while this solves the problem of having gas cylinders in the
building there is a unique danger here too.

In most places standard city gas service is too low a pressure,
often 1/4 psi, to allow a flashback arrestor to be used effectively.
Most flashback arrestors are designed to work with supply pressure of
at least 3/4 psi - if the pressure is less than that they completely
block gas flow. Jewelers don’t use them because they won’t get any

Without a flashback arrestor there is the potential for flame to
travel back through the torch, through the black pipe and to the gas
meter which explodes violently. There is flying shrapnel as the case
of the gas meter is destroyed and a significant gas leak is created.
This occurred several times in New York City last year, causing Con
Edison, the local gas utility, to do some investigation into ways to
prevent these explosions.

My company, G-TEC Natural Gas Systems, worked with Con Ed and
learned (1) while there are devices marketed as being designed
specifically to work with low pressure gas, none proved 100%
effective when tested by an independent laboratory and (2) standard
flashback arrestors, using 3/4 psi and more, which are available from
the well-known supply companies are 100% effective at preventing
flashbacks. The problem is getting sufficient gas pressure so the
flashback arrestor protects the gas line and does not block gas

The Plug -

Permit me a few words about the G-TEC Natural Gas Torch Booster,
which solves many of these problems. It is a CSA Certified device
that can boost low pressure gas pressure high enough for great torch
performance (most jewelers use 5 psi for brazing/soldering and 20 psi
for casting) and can be installed in home studios, shopping malls,
strip shopping centers and other places that may prohibit cylinder
gases. It provides high-pressure gas as it is used; there is no gas
storage. Natural gas itself, while dangerous like any gas, also has
advantages in being stable and lighter than air. By boosting gas
pressure above 3/4 psi it works with any standard flashback arrestor.
If you are interested you can find out more at www.safe-t-gas.com .

Ed Howard
G-TEC Natural Gas Systems


After much talking with a propane installer we did the following.
We bought a new 5 gal tank that has all the latest safety devices
on it. When I refill it, we have them fill it only to 4 gals so its
not full to the brim. It is checked, watched, and cared for. I have
never had any problems. 

Just as I was about to respond to this my friend the Fire Chief
walked in so I asked him about this subject. If there is a fire in
your shop the heat will expand the gas in your tank triggering the
relief valve. This expels the propane into the fire. If the tank is
outside the firemen will spot it and hose it down to keep it cool. If
you are concerned about exposure to weather don’t be, propane is
routinely stored outside.

If you are caught with inside propane you will be cited and
re-inspected and the fire marshal will look at everything. Is your
shop up to electrical, structural and zoning codes? Other people have
discussed the insurance ramifications.

Really, what is to be gained by storing larger gas tanks indoors? A
little convenience and lower cost of installation. What is to be
lost? Possibly everything in your shop (maybe your home too) and a
lot of money defending yourself in the event of a lawsuit.

I have a small two wheel dolly which I keep my small Oxygen tank and
a small Acetylene tank ( for Smith Acetylene Air ). I use a 1 lb.
disposable cylinder of propane for my Little Torch. Harbor Freight
sells these for $ 20.00 Buy bungee cords to tightly secure small
cylinders. Bigger cylinders need a larger Oxygen and Acetylene
purpose built dolly and chain. cost $ 50.00.

All of this goes into a small ventilated locker ( metal or plywood)
which you can lock up. Put the locker in a open ventilated area. Turn
off your tanks, unscrew the regulators, and cover the hose openings.
Make sure the dolly ( or bottle rack ) is stood up and not apt to
tip over. LOCK IT UP.

This practice has been OSHA approved for at least 35 years. Learn the
applicable codes and follow them.

Wheel it in for the day, wheel it out for the evening. It is easy to
do and I sleep well at night.


All pressure tanks have relief valves otherwise they are bombs
waiting to explode.

The danger from portable LP tanks of the 5 gallon variety is that the
older ones could be overfilled by inexperienced operators. It is now
illegal in the USA to refill these older tanks. The newer variety
have a built in float valve that shuts off the tank valve if someone
tries to overfill it. The new ones have a distinctive valve handle
design and the letters OPD stamped on the handle. If your tank does
not have the OPD marking ask your gas supplier to verify if it has
the Overfill Protection Device in it if it doesn’t then get a new
one that has the OPD.


James Binnion
James Binnion Metal Arts

Jim, I don't doubt your expertise one bit (and you may have saved
lives with the heads-up about burning Gorilla glue) but-- why not
use soapy water? 

Because damn near anything will burn when exposed to high pressure
oxygen and if the soap you are using gets inside the threaded
fittings when you change the tank or hoses and you turn on the
oxygen it could explode. You must always use oxygen safe materials
when working on oxygen tanks. Anything else is courting disaster.


James Binnion
James Binnion Metal Arts


This practice has been OSHA approved for at least 35 years. Learn
the applicable codes and follow them. Wheel it in for the day, wheel
it out for the evening. It is easy to do and I sleep well at night. 

This is very good advice. I may be a nervous nellie (or whatever)
but one thing I do intend to do (instead of just blindly following
what others do) is read the applicable codes as you say and follow

you guys have to admit that there are some pretty wacky bits of
advice on the forum at times. There are certain myths that jewelers
tend to repeat to others and use as guidelines, when they don’t have
any basis in reality. One example would be the pickle. How many
people out there still think something really awful will happen to
you if you get your hand in the pickle?

Remember that guy who said he was going off to his garage to
“experiment” with cyanide jewelry bombing? He promised to write and
tell us how he made out. Curiously, we haven’t heard from him. If
you’re out there, can you check in…I wonder about you sometimes.

The advice on tank/torch set-up has been varied (to say the least).
It is a bit intimidating for certain people (though this should not
be made light of on an educational forum such as this one).

Some have been really cool about the matter. Neil the jeweler even
offered to go to beginner’s studios to help. Thanks Neil. My one
wish (at the risk of offending) is that people might make sure they
have the straight scoop before they post advice. Putting a reference
to where you get your info is very helpful…as I’m more likely to
follow advice from an authority rather than from someone’s cousin
Murray who has been “doing it that way for years and, so far, has not
blown himself up”.

Safety issues are important for everyone concerned. getting the
proper info out there only helps and should not be given lightly.

Thanks again to Neil, thank you to Mr Binnion. When I get this torch
fear behind me, it’s all a go. watch out jewelry world, here I come.

Try http://www.msha.gov/Accident_Prevention/Tips/acetylenegas.htm 

Thanks for posting this link! Good stuff! I’ll look into “flame
arresters” I already have check-valves all around. FWIW, my tanks are
on a special cart that I bought at the welding store with chians to
hold in the tanks. I wish I knew the size of these tanks, but they
are approx. 4’ tall. (I use a massive cutting torch to cut apart
100oz ingots of fine silver.)


My one wish (at the risk of offending) is that people might make
sure they have the straight scoop before they post advice. 

I don’t remember where the quote came from, but I have heard, “It’s
not what you don’t know that gets you in trouble, it’s what you know
for certain that’s wrong.”