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Oxygen tank valve question


Thank you all for taking the time to read my question.

I am getting mixed on this and I am wondering what
people in the jewelry community do.

I know that for Fuel tank valves we are all supposed to just open
from 1/4 to 3/4 of a turn in case of emergency it is easily shut
down. I just read that in the case of Oxygen tanks, the valve
actually needs to be opened all the way because of the higher amount
of pressure present in the tank and the way the back-seating valve
works. If it is not opened all the way apparently there is a risk of
there being a leak in the threading of the valve itself. I had
thought that 1/4 to 3/4 turns with oxygen was also a good preventive
procedure in case of emergency. What is the best practice here?

Thank you,


High pressure tank valves use a double seating valving, therefore,
open all the way and seat the valve in the open position when it is

john dach


I learned to weld from my grandfather who was a welder. He taught me
to open the oxygen valve slowly and all the way because of the
extreme pressure.

1/4 turn open on the fuel gas, in that case acetylene, plus leave the
key or wrench used to open the tank in place so the fuel gas can be
quickly shut off if needed.

Rick Copeland
Rocky Mountain Wonders


Hi Alexia,

Oxy in a refillable cylinder is stored at approximately 2000 lbs.
per sq inch. That pressure makes it impossible to make a valve that
won’t leak if only opened partially.

The valves on oxygen tanks have 2 seats on them. One is used for the
closed position & the other is used for the full open position. To
prevent oxy from leaking out when the valve is open the valve must be
opened all the way.

Acetylene is stored at a much lower pressure & the odds of it
leaking are not very great. Therefore the valve only needs to be
partially opened.

Another point to consider is that if an accident happens will the
torch is lit & the flame needs to be extinguished quickly only the
fuel needs to be removed to put out the flame. There’s oxy in the
air so there’s no way the oxy part of the flame could not be removed
by turning off the oxy valve.



Yes, you should open the oxygen tank valve all the way and snug it
in the open position. At 1500 psi, it can leak around the valve stem,
and the tanks have double seating valves for this reason.

David L. Huffman


High pressure gas tanks like oxygen have a second seat on the valve
that seals on the fully open side this keeps the gas from leaking
around the valve stem. So yes you want to back seat the valve.

On low pressure tanks like acetylene or propane where the internal
pressure is about 1/10 of what is in a high pressure tank there is
not a back seat on the valve so there is no need to back seat them
and it has a second benefit that you note that you may be able to
shut it off quickly in an emergency.

James Binnion
James Binnion Metal Arts

I had thought that 1/4 to 3/4 turns with oxygen was also a good
preventive procedure in case of emergency. What is the best
practice here?

Years ago my oxygen supplier confirmed that the valve on an oxygen
tank should always be either fully opened or fully closed.

Elizabeth Johnson


Thanks to all responders on this question. I now truly understand
why the Oxygen tank valve is to be opened fully.

These gems of wisdom are the beauty of Orchid and its sharing
members! A special thanks to Charles L-B, Hanuman, and Ton for their
brilliant concept and ongoing operation.

Judy in Kansas, who has returned from an extended vacation and
experienced one of those miserable trips returning home - including
dealing with a blizzard.