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OXYGEN safety another Question


#1

I don’t understand could you explain more on this, does the
Oxygen gas just have to touch the oil or make contact with it
to explode ?

Marjorie lord
Australia.


#2

Marjorie, The problem is that relatively PURE oxygen is an
extremely good oxidizer, mixing any flammable substance with it
invites disaster. In a torch the mixture is controlled, and the
two gasses are consumed as they mix. However in the case of oil
in a O2 regulator the large excess of O2 will cause the oil to
burn at an explosive rate, all of it at once. This puts a great
amount of energy in a very small place very quickly. It is this
energy which actually does the damage. As to the mixture
itself, veiw it as kind of a large weight hanging from a very
thin thread, any thing can cause the thread to break (like the
friction of turning a screw), and thus the weight will fall.
WayneM


#3

In my regular job I have attended seminars where the safety
issues of welding have been addressed. At one of those the
representative of Linde (Welding supplies & Equipment) had an
oxygen regulator which had been set down on an oily surface while
the tank was changed. When the new tank valve was openned and
the oil and oxygen came in contact the explosion drove the
regulator adjusting screw blew out and thru the man’s chest,
killing him. Linde has redesigned their equipment to prevent such
a reoccurance. I always stay to the side when openning the tank
valve just in case. Also keep any tank with high pressure secured
so that that valve cannot be hit or snapped off, even the small
tanks can become torpedos if the valve breaks off. I have heard
my boss and others tell of tanks travelling blocks and going thru
concrete block walls. Ask for safety info at your gas supplier,
as a knowledgable consumer you will be able to protect yourself.

Dan Wellman


#4

Not really just touch oil. To have a fire or explosion you need
3 things: Fuel the wax or oil Oxidizer air or much much better
oxygen or some other oxidizer such as Oxygen, Chlorine or
Flourine, stong peroxides etc Ignition source this is usualy
thought to be fire or a spark but other things such as friction,
compression impacts etc can also start things going.

People are used to living in a world where the usual oxidizer is
from air with an oxygen content of 21% you experiences are
limited to that type exposure . If the oxidizer purity increases
the ignition source rewquired and the intensity of the reaction
increase very rapidly. A little boost in the oxygen concentration
of air by only a couple percent makes a fire that melts most
everything including refactories if not properly considered. The
rate of increase is almost unbelieveable.

The rule of no fuels with oxygen is not somebodies dream. It is
based on many bad incidents. Oxygen is tricky- you can get away
with doing the wrong thing some of the time then bang you have an
explosion or fire. Trust me I have seen and investigatedmany
incidents of misuse. Jesse


#5
   I don't understand  could you explain more on this, does
the Oxygen gas just have to touch the oil  or make contact with
it to explode ? 

The key is that the oxygen must be at high pressure. At room
temperature and pressure, there is little if any danger. But you
know how oily rags, in a confined area, can build up heat from
slow oxidation and spontaniously combust? Doesn’t happen often,
but has cause more than a few fires over time. We all know
better than to let it happen.

Well, in a high pressure oxygen environment, like on the high
pressure side of an oxygen regulator, where you may easily have
two thousand psi of pure oxygen, spontanious combustion isn’t a
slow or iffy thing. If it’s a combustible oil, and that includes
virtually all the petroleum and many other oils, mere contact
between oil and that high pressure oxygen atmosphere WILL cause
spontaneous combustion. Depending on the type and amount of oil,
it might be slow enough not to damage the fixture, but it doesn’t
take much oil, and if the reaction occures explosivly enough it
can cause major damage. Remember too, that if you cause slight
damamge/weakening to a fixture with that high pressure oxygen
atmosphere running around inside, the 2200 psi of the oxygen can
do the rest of the damage quite easily. oxygen tanks, like any
high pressure tank, are potential rockets or bombs, when things
go wrong. I recall seeing one instance where a SCUBA shop, in
filling air tanks (which also were filled to about 2200 psi with
just plain air, not oxygen) had dropped one, cracking the neck
of the tank. The neck blew off (consider that it’s about an inch
and a half diameter pipe there, so the total pressure on that
section was probably in the neighborhood of two tons. Then, of
course, all the gas rushes out the hole. Only takes a moment,
but for that moment, you’ve got a rocket engine that weighs only
about 20 pounds for the tank, yet has an increadible two ton
thrust. You can imagine how fast it accelerates in a very short
time. That tank took out the back cinder block wall of the shop,
and flew another hundred yards before hitting a concrete seawall,
knocking a 3 foot gap in it, and skipping another fifty yards out
to sea…

With oxygen tanks and oil, the usual danger point is the
regulator, since that’s where idiots put the oil. When it
explodes, the high pressure oxygen propels the insides of the
regulator, especially the adjustment screw, outwards at rather
high velocities… Don’t be in the way. And if, in the
process, the tank falls over and knocks it’s neck off, or
otherwise releases the full tank pressure all at once…

Peter


#6

High oxygen pressure does increase the likelyhood of a
fire-explosion incident, but: The Appolo space craft fire that
killed three men on the launch pad involved oxygen at less than
one atmosphere pressure. The ignition source was a small
electrical problem. The capsule was able to use very low pressure
and supportlife due to the fact that the total oxygen pressure
was greater than the equivelent pressure of 21% of one
atmosphere. Follow the rules no fuels with oxygen and don’t
tempt your fate- too many lost eyes and fingers have been caused
by small incidents. Jesse


#7

Chaining down tanks is a must and you all have probably heard
this a hundred times. I for one will never forget it. I worked as
a welder in 78-80 and a oxy tank got its valve knocked off. It
went through two brick walls and skated across a gravel parking
lot…the resulting dust cloud blotted out the sun for several
minutes…now you never forget an experience such as that…I was
scared to death…now as a end result my hair has two silver
streaks one on each temple he he he…besides I will never ever
forget that sound either…sounded like a jet going to crash in
our Pipe yard…

Thanks
Kemp