Safety in Welding, Cutting, and Allied Processes

ANSI Z49.1:1999
subjected in service, but in no case less than 300 psi
(2070˚kPa). Oil-free air or an oil-free inert gas shall be
used for testing.
10.6.7 Devices. Only approved devices as defined in
2.1 shall be used in oxyfuel gas systems.
10.6.7.1 The use of suitable approved flashback
arrestors shall be permitted to be used.
10.7 Pressure-Reducing Regulators
10.7.1 Approval. Only approved pressure reducing
regulators, as defined in 2.1, shall be used.
10.7.2 Designated Service. Pressure reducing regulators
shall be used only for the gas and pressures for which
they are labeled. The regulator inlet connections shall comply
with ANSI/CGA Standard V-1, Compressed Gas Cylinder
Valve Outlet and Inlet Connections.
Regulators shall not be interchanged among designated
gas services.
E10.6.7 When an approved device such as a hose check
valve or flash-back arrestor is used in an oxyfuel gas welding
and cutting torch system, the device should be used
and maintained in accordance with the manufacturers instructions.
Refer to CGA Pamphlet E-2, Standard Hose
Connection Specifications.
E10.6.7.1 Flashback arrestors can provide a certain
measure of protection against the hazards of flashback.
To maintain this protection and to ensure that they have
not become damaged or inoperative during use, a routine
inspection program should be followed as specified during
use. Also, a regular inspection program should be followed
as specified in the instructions provided by the
manufacturer.
Many years of field experience has shown various oxyfuel
gas torches to be reliable and safe apparatus when
operated in accordance with instructions recommended by
the manufacturer. Under certain circumstances, the users
failure to follow these instructions can cause the backflow
(reverse flow) of unwanted gas and/or flashback into the
upstream equipment.
E10.7.1 Refer to CGA E-4, Standard for Gas Regulators
for Welding and Cutting.
E10.7.2 Contamination can lead to explosions and fire.
10.7.3 Inspection Before Use. Union nuts and connections
on regulators shall be inspected before use to
detect faulty seats which may cause leakage when the regulators
are attached to cylinder valves or hoses. Damaged
nuts or connections shall be replaced.
10.7.4 Oxygen Gauges. Gauges used for Oxygen service
shall be marked USE NO OIL.
10.7.5 Oxygen Regulators. Regulators shall be drained
of oxygen before they are attached to a cylinder or manifold,
or before the cylinder valve is opened (see also
10.8.4.4 and 10.8.4.11). Oxygen cylinder or manifold
valves shall always be opened slowly (see 10.8.4.3 and
10.8.4.4).
E10.7.5 The regulator attached to a cylinder can be
drained of oxygen by momentarily opening and then closing
the downstream line to the atmosphere with the regulator
adjusting screw engaged and the cylinder valve
closed. The cylinder valve is then opened slowly. The
oxygen cylinder or manifold outlet connection should be
wiped clean with a clean cloth, free of oil and lint, and the
cylinder valve cracked before connecting the regulator
(see 10.8.4.3).
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