T. O. 1-1A-9
To prevent damage which can produce dangerous leaks, do not drop or handle compressed gas cylinder roughly.
High pressure gas cylinders, especially oxygen shall not be used without the proper pressure reducing/control
Pressurized oxygen shall not be used as a substitute for compressed air, artificial ventilation, or for other
Cylinders in use will be kept in an upright position and properly secured and protected to prevent them. from
being accidentally knocked over or damaged.
2-213. PREPARATION FOR AND WELDING CONTAINERS. Before welding any tank, cylinder or other container,
action shall be taken to make certain that they do not contain any flammable or explosive substance (i.e., liquid, gas,
etc.). The containers which contain or have contained flammable substances will be adequately purged or inerted prior
to welding. Sealed containers will not be welded until contents are investigated as cited above and provisions are made
for venting during and after welding, until properly cooled. Adequate venting is necessary to prevent explosion or rupture
of container because of increased/decreased pressure that will occur to a closed container from the heating and cooling
2-214. Gasoline tanks and other containers that have or had flammable liquids in them will be drained, flushed and
steamed and if practicable filled with water before welding. Other approved process may be used when specified and
approved by responsible engineering activity. For maximum safety, the containers will be welded/repaired as soon as
possible after draining and cleaning.
2-215. OXYACETYLENE WELDING (SAFETY). Careful handling of the gases and equipment used in oxyacetylene
welding is essential to prevent serious injury to personnel and d2amage to equipment and material. The following
precautions will be taken:
Oil or grease will not be allowed to come in contact with welding equipment. If grease or oil is ignited
accidentally the possibility exists of oxygen supported explosion.
Acetylene (cylinders) will not be used at pressures exceeding 15 pounds per square inch The special (T) wrench
used to open/close cylinders will be left in place during welding operations to permit shut down in emergencies. Control
valves will be unobstructed and readily accessible to the welder throughout the operation. Special control and
emergency cut-off valves will be checked at regular intervals for proper operation. Cylinders will be carefully handled to
prevent damaging the regulators and valves. When cylinders are not in use, control valves will be covered by protective
caps, specifically designed for that purpose.
The flexible hoses used to supply gas to the welding torch will be of the proper type and color. The hose will be
protected from damage caused by contact with hot metal, open flames or other destructive agents. Hoses will be
inspected periodically for leaks by submerging in water. An open flame will not be used under any circumstances to test
hoses for leaks. Only standard ferrules, clamps and other fittings will be used to secure hoses to cylinders, regulators,
and torches. Makeshift tape or wire connections will not be permitted.
After the welding torch is ignited, the flame will be kept within vision and control of the welder at all times. The
welder shall not allow the torch to contact flammable materials, any part of the welding system and items that should not
be heated. The welder will not point torch at concrete surfaces as a miniature explosion will occur resulting in flying
fragments of concrete. When the torch is not in use, it will be extinguished and control valves will be turned OFF.
When a flash-back occurs, both torch valves will be immediately closed. If a hose bursts, or escaping gas ignites
at the tank, regulator controls will be turned OFF immediately.
2-216. ELECTRIC ARC WELDING SAFETY. Electrical shock is an added hazard of arc welding. Electrical fires
caused by generating equipment and the arc itself add to the dangers of this operation. Fire resistant curtains or screens
will be used during arc welding operations to protect personnel from eye injuries caused by intense arc flashes. The
following additional precautions will be taken.
The electrical and other components of the arc welding equipment will only be checked when the circuits are
dead. The electrical circuits shall be checked only by a qualified electrician.
Rotary and polarity switches will not be operated while the equipment is under an electrical load.
Motor-generator and other electrical welding equipment will have effective grounds, which will be used when the
equipment is in operation. Grounding of arc welding machinery will be done according to the provisions of the National
Electrical Safety Code (Reference National Electrical Safety Code Article 250).
Arc welding equipment will be inspected periodically to insure safe and efficient operation. Power cables, ground
wire and electrode holders, will be carefully inspected for defects that could cause shock. Necessary repair to arc
generators and equipment will be made immediately upon detection by qualified electricians.