Page 217 - International safety guide for oil tankers and terminals

SHIPBOARD OPERATIONS
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11.1.15.3
11.1.15.4
possible. However, some terminals will require the ship to displace
the contents of the hoses or arms, and perhaps also the shore
pipelines, with water on completion of cargo operations. Due to
the added risk of pollution, this practice should only be
undertaken if it is essential and must be carefully planned and
executed. Prior to commencing the displacement, the ship and
terminal should reach agreement on the procedures to be
adopted, particularly the amount to be pumped and the pumping
rate.
Particular attention must be paid to venting the cargo pumps and
guaranteeing that no outflow of oil occurs when opening the sea
valve.
Reference should be made to the ICS/OCIMF publication
‘Prevention of Oil Spillages through Cargo Pumproom Sea
Valves’.
Line Draining
On completion of loading, the ship’s cargo deck lines should be
drained into appropriate cargo tanks to ensure that thermal
expansion of the contents of the lines cannot cause leakage or
distortion. The hoses or arms, and perhaps a part of the pipeline
arms and ship or shore lines.ึ
system between the shore valve and the ship’s manifold, are also
usually drained into the ship’s tanks. Sufficient ullage must be left
in the final tanks to accept the cargo oil drained from hoses or
On completion of discharge, the ship’s cargo deck lines should be
drained into an appropriate tank and then discharged ashore or
into a slop tank.
When draining is complete, and before hoses or arms are
disconnected, the ship’s manifold valves and shore valves should
be closed and the drain cocks at the ship’s manifold should be
opened to drain into fixed drain tanks or portable drip trays. Cargo
manifolds and arms or hoses should be securely blanked after
being disconnected. The contents of portable or fixed drip trays
should be transferred to a slop tank or other safe receptacle.
Clearing Hoses and Loading Arms to the
Terminal
If hoses or arms have to be cleared to the terminal using
compressed air or inert gas, the following precautions should be
strictly observed in order to avoid the possible creation of a
hazardous static electrical charge or mechanical damage to tanks
and equipment:
The procedure to be adopted must be agreed between ship
and terminal.
There must be adequate ullage in the reception tank.
To ensure that the amount of compressed air or inert gas is
kept to a minimum, the operation must be stopped when the
line has been cleared.
The inlet to the receiving tank should be located well above
any water that may be in the bottom of the tank.
© ICS/OCIMF/IAPH 2006 183