I have never heard about an explosion with acetylene and have
seen many "leaky regulators.Would it help to keep the window
cracked in the studio? Thanks
As I mentioned, I would never keep an acetylene tank in my home
and I suspect it is against the fire code in many areas. I do
recognize that many people do keep B tanks in their homes and
have done so for years without incident. In the recent digest on
this topic there were quite a few opinions about the safety of
using these gases. I think it would be interesting if people who
have had experiences with leaking tanks or fires or explosions
would post details of the incidents for us all to read.
You asked about leaky regulators. A small leak from a regulator
is likely to harmlessly dissipate in a room with only moderate
ventilation (such as an open window). Once the gas has
dissipated, there is little risk of explosion. Any kind of
ventilation, including keeping the window cracked open would
Most gas releases happen because someone makes a mistake and the
gas starts to flow out while they are standing near the tank. If
the tank has been set up properly, (see David Arens' excellent
note in the July 28 Digest) it is usually just a quick quarter
turn of a valve to stop the gas flow and an incident can likely
be avoided. If proper procedures are followed and tank valves are
closed when the tank is left unattended, the tank is chained so
it can't fall etc etc, there is only a small chance that gas will
leak from the tank.
Propane tanks are an exception to the above. Due to the nature
of the pressure relief valve on the tank, it is possible for the
valve to open at any time under certain condidions and release
enough propane into your home to cause a serious explosion.
You mentioned lead plugs in your note, so here is bit of
background on lead plugs and pressure relief valves:
When a flammable gas, or liquified gas (as in the case of
propane) is stored in a sealed container, the gas can expand in
the container if heat is applied to it. As the gas expands it has
no place to go, so instead of expanding it creates pressure in
the tank. The hotter the tank gets the higher the pressure gets.
The tanks are designed to handle a certain maximum pressure
safely. If the pressure inside that tank exceeds its safe design
pressure, there is a possibility that the tank will rupture.
Manufacturers of these tanks are required by law to protect the
tanks from exceeding their maximum safe design pressure. This is
generally done by installing a device on the tank that will allow
some (or all ) of the gas to escape from teh tank, thus relieving
the pressure and preventing the tank from rupturing.
A typical 20 pound propane tank, is generally equipped with a
spring type pressure relief valve. This valve will open at
perssures in excess of the design pressure and will close once
the tank pressure is below design pressure. The amount of propane
released will be limited to that required to reduce the tank back
to a safe pressure.
Most other gas tanks, and I believe that acetylene tanks will
fit into this category, have the lead plug that you refer to. It
is called a fusible plug. This fusible plug will melt if exposed
to very high heat which it takes to overpressure the gas tank.
Once it melts, it does not reseal like the valve on a propane
tank. This means that if it melts, all of the gas inside the tank
will be released, thus preventing the tank from rupturing.
The fusible plug will only melt when the tank is exposed to the
intense heat of a fire. It takes far more heat than just leaving
the tank in the hot sun, or lighting your torch near it. I have
never heard of a fusible plug melting unless there is a huge fire
around the tank.
You may be wondering why it is a good idea to purposefully
release the contents of a flammable gas tank into a fire as this
would continue to feed the fire and make it worse. The reason is
that if there were no relief valves or fusible plugs on gas
tanks, then if a tank overpressures and ruptured, it could send
metal fragments flying hundreds of feet with a very high and
dangerous force at the same time the gas is being released.
Hopefully this sheds some light on a confusing subject and has
not made it even more confusing.
As I mentioned at the beginning, I would not keep any of these
gasses in my home and you should consult your local fire
department for laws and safety regulations pertaining to the safe
handling and storage of flammable gasses.