(g) Inspect the inside of the container to see if it is clean. To do
this use a mirror to reflect light into the container. If inspection shows that it
is not clean, repeat steps (d), (e), and (f) above and inspect. (Use a nonmetal
electric lantern or flashlight suitable for inspection of locations where flammable
vapors are present.)
(h) Close the container openings. In 15 minutes reopen the container and
with a combustible gas indicator test for gas vapor. If the vapor concentration
is in excess of 14 percent of the lower limit of flammability, repeat the cleaning
procedure.
(4) If steaming facilities for heating the chemical solution are not
available, a less effective method is the use of a cold water solution with the
amount of cleaning compound increased to about 6 oz per gallon of water. It will
help if the solution is agitated by rolling the container or by blowing air through
the solution by means of an air line inserted near the bottom of the container.
h. Marking of safe containers. After cleaning and testing that a container
is safe for welding and cutting, stencil or tag it. The stencil or tag should
include a phrase such as: "Safe for welding and cutting", the signature of the
person so certifying, and the date.
i. Filling treatment. It is desirable to fill the container with water during
welding or cutting as a supplement to any of the cleaning methods. Where this
added precaution is taken, place the container so that it can be kept filled to
within a few inches of the point where the work is to be done. Make sure the space
above the water level is vented so that the heated air can escape from the
container.
8. SUMMARY. There are many other safety precautions to be considered, but
safety measures normally associated with oxygen-acetylene operations are the ones
covered in the rest of this lesson. Be sure to consult TM 9-237, Operator's
Manual, Welding Theory and Operation, before attempting to perform any other type
of operation.
EXERCISE
31.
Acetylene should never be used at pressures in excess of
a.
10 PSI.
b.
15 PSI.
c.
20 PSI.
32.
If an outlet valve on an acetylene cylinder has become clogged with ice, the
ice should be thawed by
a.
using warm water.
b.
using scalding water.
c.
using open flame.
33.
When using an oxygen cylinder, how far is the valve opened?
a.
One full turn
b.
Three full turns
c.
Full limit
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