Page 249 - International safety guide for oil tankers and terminals

SHIPBOARD OPERATIONS

initially very high potential has had a chance to decay to a more
tolerable level. A wait of 30 minutes after stopping the injection of
---ใช้เพื่อการศึกษาเท่านั้น---
inert gas is sufficient for this purpose. After 30 minutes, equipment
may be introduced, subject to the same precautions as for water
mists caused by washing (see Section 11.8.2.5).
sampling and gauging procedures if possible.พาณิชย์นาวี

11.8.4 Measuring and Sampling Cargoes Containing
Toxic Substances

Special precautions need to be taken when ships carry cargoes that
contain toxic substances in concentrations sufficient to be hazardous.

Loading terminals have a responsibility to advise the Master if the cargo
to be loaded contains hazardous concentrations of toxic substances.
Similarly, it is the responsibility of the Master to advise the receiving
terminal that the cargo to be discharged contains toxic substances. This
transfer of information is covered by the Ship/Shore Safety Check-List
(see Section 26.3).

The ship must also advise the terminal and any other personnel, such as
tank inspectors or surveyors, if the previous cargo contained toxic
งานห้องสมุด ศูนย์ฝก
substances.

ึ
Ships carrying cargoes containing toxic substances should adopt closed

When closed gauging or sampling cannot be undertaken, tests should be
made to assess the vapour concentrations in the vicinity of each open
access point, in order to ensure that concentrations of vapour do not
exceed the Short Term Exposure Limit (TLV-STEL) of the toxic
substances that may be present. If monitoring indicates the limit could be
exceeded, suitable respiratory protection should be worn. Access points
should be opened only for the shortest possible time.

If effective closed operations cannot be maintained, or if concentrations
of vapour are rising because of defective equipment or due to still air
conditions, consideration should be given to suspending operations and
closing all venting points until defects in equipment are corrected, or
weather conditions change and improve gas dispersion.

Reference should be made to Section 2.3 for a description of the toxicity
hazards of petroleum and its products.

11.8.5 Closed Gauging for Custody Transfer

The gauging of tanks for custody transfer purposes should be effected by
the use of a closed gauging system or via vapour locks. For the ullaging
system to be acceptable for this purpose, the gauging system should be
described in the ship’s tank calibration documentation. Corrections for
datum levels, and for list and trim, should be checked and approved by
the ship’s classification society.

Temperatures can be taken using electronic thermometers deployed into
the tank through vapour locks. Such instruments should have the
appropriate approval certificates and should also be calibrated.

Samples should be obtained by the use of special sampling devices using
the vapour locks.

© ICS/OCIMF/IAPH 2006 215