Page 215 - International safety guide for oil tankers and terminals

SHIPBOARD OPERATIONS
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11.1.14.8
งานห้องสมุด ศูนย์ฝกพาณิชย์นาวี
11.1.14.9
11.1.14.10 Periodic Checks During Discharge
Discharge should start at a slow rate and only be increased to the
agreed rate once both parties are satisfied that the flow of oil to
and from designated tanks is confirmed.
Commencement of Discharge at an Offshore
Terminal
Before commencing discharge at an offshore terminal,
communications between ship and shore should be tested and
fully understood. The ship must not open its manifold valves or
start its pumps until a clear signal has been received from the
shore that the terminal is ready. Discharge must be started slowly
until the system has been tested and then gradually brought up to
the maximum agreed flow rate or pressure. A close watch should
be kept on the sea in the vicinity of the hoses to detect leaks.
During darkness, a bright light should, where safe and practicable,
be shone on the water in the vicinity of the hoses.
Commencement of Discharge Through a Stern
Discharge Line
Before commencing discharge through a stern line, a dangerous
area extending not less than 3 metres from the manifold valve
should be clearly marked and no unauthorised personnel should
ึ
be allowed within this area during the entire discharge operation.
A close watch must be maintained for any leakage and all
openings, air inlets and doors to enclosed spaces should be kept
tightly closed.
Fire-fighting equipment must be laid out and ready for use in the
vicinity of the stern manifold.
Throughout discharging, the ship should monitor and regularly
check all full and empty tanks to confirm that cargo is only leaving
the designated cargo tanks and that there is no escape of cargo
into pumprooms or cofferdams, or through sea and overboard
discharge valves.
The ship should check tank ullages at least hourly and calculate a
discharge rate. Cargo figures and rates should be compared with
shore figures to identify any discrepancy. These checks should,
where possible, include the observations and recording of the
shear forces, bending moments, draught and trim and any other
relevant stability requirements particular to the ship. This
information should be checked against the required discharging
plan to see that all safe limits are adhered to and that the
discharging sequence can be followed, or amended, as
necessary. Any discrepancies should be immediately reported to
the Responsible Officer.
Any drop in pressures or any marked discrepancy between tanker
and terminal estimates of quantities could indicate pipeline or
hose leaks, particularly in submarine pipelines, and require that
cargo operations be stopped until investigations have been made.
© ICS/OCIMF/IAPH 2006 181