(e) Inspect the inside of the container as described in paragraph ?g(3)
(g).
If it is not clean, repeat steps (a)(b)(c) and (d) above.
(f) Close the container openings.
In 15 minutes test a gas sample as
described in paragraph 7g(3)(h).
f. Water method of cleaning.
(1) Water-soluble substances can be removed by repeatedly filling and
draining the container with water. Water soluble acids, acetone, and alcohol can
be removed in this manner. Diluted acid frequently reacts with metal to produce
hydrogen; care must be taken to see that all traces of the acid are removed.
(2) When the original container substance is not readily water soluble, it
must be treated by the steam method or hot chemical solution method.
g. Hot chemical solution method of cleaning.
(1) The chemicals generally used in this method are trisodium phosphate
(strong washing powder) or a commercial caustic cleaning compound dissolved in
water to a concentration of 2 to 4 oz of chemical per gallon of water.
(2) When cleaning by this method guard against injury from steam or the
caustic cleaning compound. Use suitable goggles, gloves, and other protective
clothing.
(3) The procedure for the hot chemical solution method of cleaning is as
follows:
(a) Close all container openings with the exception of the drain and
filling connection or vent. Use damp asbestos, damp wood flour, or similar
material for sealing cracks or other damaged sections.
(b) Fill the container to overflowing with water, preferably letting
water in through the drains. If there is no drain, flush the container by
inserting the hose through the filling connection or vent. Lead the hose to the
bottom of the container to get agitation from the bottom upward. This causes any
remaining liquid, scum, or sludge to be carried upward and out of the container.
(c) Drain the container thoroughly.
(d) Completely dissolve the amount of chemical required in a small
amount of hot or boiling water and pour this solution into the container. Then
fill the container with water.
(e) Make a steam connection to the container either through the drain
connection or by a pipe entering through the filling connection or vent. Lead the
steam to the bottom of the container. Admit steam into the chemical solution and
maintain the solution at a temperature of 170 to 180F. At intervals during the
steaming add enough water to permit overflowing of any volatile liquid, scum, or
sludge that may have collected at the top. Continue steaming until the point is
reached when no appreciable amount of volatile liquid, scum, or sludge appears at
the top of the container.
(f) Drain the container.
102
Previous Page
