Page 381 - International safety guide for oil tankers and terminals

PRECAUTIONS ON SHIP AND TERMINAL DURING CARGO HANDLING

24.3.2 Sighting and Ullage Ports
24.3.4ื่อการศึกษาเท่านั้น---
During any of the cargo and ballast handling operations referred to in
Section 24.1, sighting and ullage ports should be kept closed, unless
required to be open for measuring and sampling and when agreed
between the ship and the terminal.
งานห้องสมุด ศูนย์ฝกพาณิชย์นาวี
If, as a result of the system design, sighting or ullage ports are required
to be open for venting purposes, the openings should be protected by a
flame screen which may be removed for a short period during ullaging,
sighting, sounding and sampling. These screens should be a good fit and
should be kept clean and in good condition.

24.3.3 Cargo Tank Vent Outlets
The cargo tank venting system should be set for the operation concerned.
High velocity vents should be set in the operational position to ensure the
high exit velocity of vented gas.

When volatile cargo is being loaded into tanks connected to a venting
system which also serves tanks into which non-volatile cargo is to be
loaded, particular attention should be paid to the setting of
pressure/vacuum valves and the associated venting system, including any
inert gas system, in order to prevent flammable gas entering the tanks to
ึ
be loaded with non-volatile cargo.
Whenever tanks are isolated to prevent cross-contamination, the
likelihood of oxygen entering the tank due to pressure variations on
passage should be taken into consideration and measures may need to
be planned to restore the inert condition prior to discharge.
---ใช้เพ

Tank Washing Openings
During tank cleaning or gas freeing operations, tank washing cover plates
should only be removed from the tanks in which these operations are
taking place and should be replaced immediately upon completion. Any
openings in the deck should be covered by gratings. Other tank washing
covers may be loosened in preparation, but they should be left in their
fully closed position.

24.4 Inspection of Ship’s Cargo Tanks Before Loading

Where possible, inspection of ship’s tanks before loading cargo should be made
without entering the tanks.

Tank atmospheres which are, or which have been, inerted frequently have a blue
haze which, together with the size of the tanks, makes it difficult to see the bottom
even with the aid of a powerful torch or strong sunlight reflected by a mirror. Other
methods such as dipping and measuring the heel, or having the stripping line or
eductors opened in the tank and listening for suction, may then have to be used. It
may sometimes be necessary to remove tank cleaning opening covers to sight parts
of the tank not visible from the ullage or sighting ports, but this should only be done
when the tank is gas free. The covers must be replaced and secured immediately
after the inspection. The person carrying out the inspection should take care not to
inhale vapours or inert gas when inspecting tanks that have not been gas freed.

© ICS/OCIMF/IAPH 2006 347