(7) Where a liquid or gaseous oxygen system is used to supply gaseous oxygen for
welding and cutting and the system has a storage capacity of more than 20,000 cubic feet
(560 cubic meters), measured at 14.7 psia and 70 degrees Fahrenheit, including
unconnected reserves at the site, the system shall be as prescribed in National Fire
Protection Association Standard NFPA 50, “Standards for Bulk Oxygen Systems at
Consumer Sites,” 1974 edition, which is adopted by reference in R 408.40709.
History: 1980 AACS; 2005 AACS; 2013 AACS; 2015 AACS.
R 408.40723 Cylinders generally.
Rule 723. (1) A chain, bracket, or other restraining device shall be used at all times
to prevent cylinders from falling.
(2) A cylinder shall stand valve end up at all times.
(3) A cylinder shall not be dropped, dragged, rolled on its side, or struck violently.
(4) When using a crane or hoisting device, a cylinder shall be lifted only by cradles
or enclosed platforms. An electromagnet, hook, rope, or sling shall not be used.
(5) A frozen or ice-clogged valve shall be thawed either by warm air or warm water
and shall be dried before using. Boiling water or a flame shall not be used. Force shall not
be applied to a valve or cap to loosen a cylinder frozen in place.
(6) Gases shall not be mixed within a cylinder except by the supplier. Only the
owner of the cylinder, if the owner is qualified, or a person trained, qualified, and
authorized by the owner, shall refill a cylinder. The contents of a cylinder shall be used
only for those purposes intended by the supplier.
(7) A cylinder shall not be placed where it will become a part of the electrical circuit
by accidental grounding or where it may be burned by an electric welding arc. A cylinder
shall not be placed so that hot slag or flame can reach it unless the cylinder is protected
by a fire-resistant shield. An electrode shall not be tapped against a cylinder to strike an
(8) A regulator, gauge, or hose shall not be interchangeable between fuel gas,
oxidizing gas, or inert gas. Connections for compressed gas cylinders shall be as
prescribed in American National Standard Institute Standard ANSI/ASA B57.1, 1965
edition, “Compressed Gas Cylinder Valve Outlet and Inlet Connections,” which is
adopted by reference in R 408.40709.
(9) A cylinder valve shall be opened slightly for an instant and then closed before
connecting to a regulator or manifold to clear the valve of dust and dirt. The employee
opening the valve shall stand to one side of the outlet, not in front of it. The employee
shall not open the valve near a source of ignition. Pressure to a regulator shall be
introduced by slowly opening the cylinder valve. An acetylene cylinder valve shall only
be opened enough to allow proper working pressure, but shall not be opened more than 1
1/2 turns of the spindle.
(10) Acetylene shall not be utilized or piped, except in cylinder manifolds, at a
pressure in excess of 15 psig.
(11) A cylinder to which a regulator is attached shall not be moved unless secured to
a hand or powered truck designed or equipped for this purpose.
(12) A cylinder valve must be closed in any of the following situations:
(a) When moving the cylinder.