Remove two vent caps (11).
Ensure that steam does not come in contact with electrical wiring and other
tank components. Heat from steam can damage painted surface of tank,
can weaken fusible plugs, and damage valve seats, gaskets, and dia-
phragms. Failure to follow this caution may result in damage to electrical
wiring and other tank components.
Introduce steam through two vent cap (11) openings and manhole opening in sufficient
volume to raise temperature of tank interior to 170F (76C).
(10) Remove transfer hoses from curbside hose and gage stick tube assembly (6). Introduce
steam into tube assembly.
(11) Steam tank and vapor collection system for at least three hours. Turn off steam source.
After purging, keep manhole fill cover (12) open during cool-down to pre-
vent vacuum collapse of tank.
(12) Leave all openings open until tank is fully cooled, at least one hour.
(13) Use combustible gas indicator set to test air inside tank, vapor collection return line (5), front
port (1), and hose and gage stick tube assembly (6) (see FM 10-20). If reading indicates tank
is not safe, resume steam cleaning for 1 hour, then retest.