other help as the situation demands. If the welder
--Use only approved apparatus that has been
must enter the space through a manhole or other
examined and tested for safety.
small space, a lifeline and safety belt must be
attached to the welder's body so that the welder can
--Stow all cylinders carefully according to
be quickly removed in an emergency. This
prescribed stowage procedures. Cylinders should be
equipment must be attached in such a way that the
stowed in dry, well-ventilated, well-protected places,
welder's body cannot be jammed in the small
away from heat and combustible materials. Do
N O T stow oxygen cylinders in the same
compartment as acetylene or other fuel gas
The discussion thus far has been primarily
cylinders. All cylinders should be stowed in an
concerned with compartments and tanks that are
upright position rather than horizontally. If
part of the ship's structure. Certain special
acetylene cylinders are not stowed in an upright
precautions should be noted for welding or cutting
position (valves at top), they must not be used until
on any hollow metal article, whether the work is
they have been allowed to stand in an upright
performed in or out of a welding shop.
position for at least 2 hours.
Before allowing any welding or cutting to be
--Do not allow anyone to tamper with cylinder
done, be sure that if the hollow metal article has
ever held a flammable substance, it is cleaned and
made safe. Even a trace of flammable material in
--When cylinders are in use, keep them far
a drum, tank, or other hollow article would
enough away from the actual welding or cutting so
constitute a tremendous hazard. A container that
they will not be reached by sparks, hot slag, or
has held a flammable substance may be cleaned with
steam if the substance is easily vaporized. For
removing heavy oils, a strong solution of caustic
--Never place a cylinder in such a position that
soda or a similar chemical is usually used.
it could form part of an electrical circuit.
Thorough rinsing of the article is necessary. After
a container has been cleaned, it should (if possible)
--Never interchange hoses, regulators, or other
be filled with water, carbon dioxide, or nitrogen.
apparatus intended for oxygen with those intended
This precaution should be taken since it may be
impossible to remove all traces of oil or grease from
the seams or corners of the container.
--Never attempt to transfer acetylene from one
cylinder to another, to refill an acetylene cylinder,
Hollow metal articles must be vented before
or to mix any other gas with acetylene.
being welded or cut, whether or not they have ever
contained a flammable substance. If they are not
--Keep the valves closed on empty cylinders.
vented, the increase in air pressure that occurs when
heat is applied may be sufficient to cause an
--Do not stand in front of cylinder valves while
OPERATION OF EQUIPMENT
--When a special wrench is required to open a
cylinder valve, leave the wrench in position on the
Safety precautions for the operation of welding
valve stem while the cylinder is being used so that
equipment vary considerably because of the
the valve can be closed rapidly in an emergency.
different types of equipment involved.
Consequently, only general precautions pertaining to
--Keep oxygen cylinders and fittings away from
gas welding and to metal-arc welding are given here.
oil and grease.1 Even a small amount of oil or
Further precautions may be found in chapter 1 of
grease may ignite violently, with explosive force, in
this manual, in the references already mentioned,
the presence of oxygen. NEVER lubricate any part
and in the technical manuals furnished by the
of an oxygen cylinder, valve, or fitting.
manufacturers of the equipment.
Precautions for the operation of gas welding
--Do not drop cylinders. Do not handle them
equipment include the following:
roughly. Rough handling may cause a cylinder valve