to break off, and the sudden release of gas from a
—Before starting to work, make sure that the
full cylinder may cause it to take off like a rocket.
welding machine frame is grounded, that neither
terminal of the welding generator is bonded to the
—Always open cylinder valves slowly. (Do not
frame, and that all electrical connections are
open the acetylene cylinder valve more than 1 1/2
securely made. The ground connection must be
turns.)
attached firmly to the work, not merely laid loosely
upon it.
—Close cylinder valves before moving cylinders.
—When using portable machines, take care to
—Never attempt to force unmatching or crossed
see that the primary supply cable is laid separately
threads on valve outlets, hose couplings, or torch
so that it does not become entangled with the
valve inlets. The threads on oxygen regulator
welding supply cable.
outlets, hose couplings, and torch valve inlets are
right-handed; for acetylene, these threads are
—When stopping work for any appreciable
left-handed. The threads on acetylene cylinder
length of time, be SURE to de-energize the
valve outlets are right-handed, but have a pitch that
equipment. When not in use, the equipment should
is different from the pitch of the threads on the
be completely disconnected from the source of
oxygen cylinder valve outlets. If the threads do not
power.
match, the connections are mixed.
—Keep welding cables dry and free of oil or
—Always use the correct tip or nozzle and the
grease. Keep the cables in good condition, and at
correct pressure for the particular work involved.
all times take appropriate steps to protect them
This information should be taken from tables or
from damage. If it is necessary to carry cables some
worksheets supplied with the equipment.
distance from the machines, run the cables
overhead, if possible, using adequate supporting
—Do not allow acetylene or acetylene and
devices.
oxygen to accumulate in confined spaces. Such
mixtures are highly explosive.
SAFETY OF PERSONNEL
—Keep a clear space between the cylinders and
If it is necessary for a welding operator to work
the work so that the cylinder valves may be reached
on platforms, scaffolds, or runways at an elevation
quickly and easily if necessary.
of more than 5 feet, provisions should be made to
prevent falling. This can be accomplished by the
—When lighting the torch, open the acetylene
use of a railing or some other equally effective
valve first and ignite the gas while the oxygen valve
safeguard.
is still closed. Do not allow unburned acetylene to
escape and accumulate in small or closed
Helmets or hand shields should be used during
compartments.
all arc welding or arc cutting operations. Goggles
should also be worn by personnel in the vicinity of
—When extinguishing the torch, close the
arc welding or cutting operations to protect eyes
acetylene valve first and then close the oxygen valve.
from injurious rays from adjacent work and from
flying objects. The goggles may have either clear
glass or colored glass, depending on the amount of
—When welding or cutting is stopped for a
period of 15 minutes or more, or when the operator
exposure to adjacent welding operations. Helpers
leaves the area, the equipment must be secured.
or attendants should be provided with proper eye
protection.
Precautions for the operation of metal-arc
welding equipment include the following:
Goggles or other suitable protection should be
used during all gas welding or oxygen cutting
operations.
—Use only approved welding equipment, and be
sure that it is in good condition.
The specifications for protectors are as follows:
7-24
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