NEVER work alone inside a tank: a second person must be stationed at
the manhole opening. The person inside the tank must have a safety line
and harness on in case of emergency for rescue operations. In the event
a rescue operation is required, summon assistance IMMEDIATELY. DO
NOT attempt a rescue until assistance has arrived.
When working inside tank, always provide adequate forced air ventilation
at the manhole opening with air directed into compartment where work
is being performed. Forced air ventilation allows for removal of any ex-
plosive quantities and contaminants resulting from the type of work be-
ing done and serves to prevent oxygen deficiency. Failure to follow this
warning may result in death to personnel.
(14) If repair to tank is scheduled, emergency valve must be removed at this time (see paragraph
4-82), Even with tank drained and purged, approximately 3-4
cc of fuel remain inside piston
cavity of emergency valve. Vapor will continue to escape from emergency valve and create a
Compressed air used for drying tubing must not exceed 30 psi (207 kPa).
Wear protective clothing (goggles, face shield, and gloves) and use caution
to avoid injury to personnel.
(15) Open precheck valve inside cabinet (see paragraph 2-2). From outside tank, disconnect
precheck tubing from check valve, elbows at piping assembly, and pressure gage (see para-
graph 4-72). Allow any fuel inside tubing
to drain. Force compressed air through tubing
tubing. Thoroughly wipe up any fuel that drains.
(16) Enter tank when it tests SAFE and remove jet level sensor (see paragraph 4-70).
(17) Allow all fuel to drain from precheck and jet level sensor tubing. Force compressed air
through tubing lo dry tubing. Thoroughly wipe up any fuel that drains.
(18) Retest with combustible gas indicator set (see FM 10-20). Resteam as required until a SAFE
reading is obtained.
(19) Connect precheck tubing to pressure gage, elbows at piping assembly, and check valve (see
(20) Install jet level sensor and connect precheck and jet level sensor tubing at jet level sensor end
(21) After purging and obtaining a SAFE reading with combustible gas indicator set, disconnect all
(22) Remove all pails at drain points and dispose of contents in accordance with local policy.
(23) Semitrailer is ready for tank inspection or repair, a change in material, or shipment, as appli-
cable. Tank is also safe to be brought inside a building for maintenance.