3.2.1 Ensure that the cargo tank to be tested
and its associated piping have been cleaned and that the cargo tank
is safe for entry.
3.2.2 Fill the cargo tank with water to a depth
necessary to carry out normal end of unloading procedures.
3.2.3 Discharge and strip water from the cargo
tank and its associated piping in accordance with the proposed procedures.
3.2.4 Collect all water remaining in the cargo
tank and its associated piping into a calibrated container for measurement.
Water residues shall be collected, inter alia, from the
following points:
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.1 the cargo tank suction and its vicinity;
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.2 any entrapped areas on the cargo tank bottom;
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.3 the low point drain of the cargo pump; and
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.4 all low point drains of piping associated with
the cargo tank up to the manifold valve.
3.2.5 The total water volumes collected above
determine the stripping quantity for the cargo tank.
3.2.6 Where a group of tanks is served by a common
pump or piping, the water test residues associated with the common
system(s) may be apportioned equally among the tanks provided that
the following operational restriction is included in the ship’s
approved Manual: "For sequential unloading of tanks in this group,
the pump or piping is not to be washed until all tanks in the group
have been unloaded."
The above figures illustrate test arrangements that would provide a
backpressure of not less than 100 kPa at the cargo tank’s unloading manifold.