Page 208 - International safety guide for oil tankers and terminals

INTERNATIONAL SAFETY GUIDE FOR OIL TANKERS AND TERMINALS

monitoring for vapour, personal protective equipment to be
used, accommodation and engine room ventilation
---ใช้เพื่อการศึกษาเท่านั้น---
arrangements and emergency measures that have been put in
place.

Closed loading procedures described in Section 11.1.6.6
งานห้องสมุด ศูนย์ฝกพาณิชย์นาวี
should be used.
Venting to the atmosphere at a relatively low tank pressure
should be avoided, particularly in calm wind conditions.
Cargo loading should be stopped if there is no wind to
disperse the vapours or if the wind direction takes cargo
vapours towards the accommodation.
Only personnel actively engaged in ship security and cargo
handling should be permitted on open decks. Regular
maintenance on deck should be limited or postponed until after
the end of cargo operations. Visitors should be escorted to
and from the accommodation spaces and briefed on the
hazards of the cargo and emergency procedures.
H 2 S is very corrosive and mechanical gauges are therefore
more likely to fail than usual. Their operational condition should
be checked frequently. In the event of a gauge failure, repairs
should not be undertaken unless an appropriate permit has
been issued and all necessary precautions observed.
ึ
H 2 S is heavier than air. In ship-to-ship transfers, particular
attention should therefore be given to the difference in
freeboards of the ships and the possibility of vapour not being
dispersed freely. Vent velocities should be kept high on the
receiving ship and the ships should be turned so as to allow
the wind to carry vapours away from the accommodation
spaces.

11.1.10 Loading Cargoes Containing Benzene
Guidance on benzene toxicity is to be found in Section 2.3.5. Cargoes
containing benzene should be loaded using the closed operation
procedures described in Section 11.1.6.6 as this will significantly reduce
exposure to benzene vapour. Where a Vapour Emission Control System
(VECS) is available ashore, it should be used (see Section 11.1.13).

Operators should adopt procedures to verify the effectiveness of the
closed loading system in reducing the concentrations of benzene vapours
around the working deck. This will involve surveys to determine the
potential for exposure of personnel to benzene vapour during all
operations such as loading, discharging, sampling, hose handling, tank
cleaning, gas freeing and gauging of cargoes containing benzene. These
surveys should also be carried out to ascertain vapour concentrations
when tank cleaning, venting or ballasting tanks whose previous cargo
contained benzene.
Spot checks on vapour concentrations, using detector tubes and pumps,
toxic analysers or an electronic detector tube, should be carried out by
ship’s personnel to ascertain if TLV-TWAs are being exceeded and
therefore whether personal protective equipment should be worn.

In addition to the above, the precautions described in Section 11.8.4
should also be taken in order to minimise exposure when measuring and
sampling cargoes containing benzene.

174 © ICS/OCIMF/IAPH 2006