Page 135 - International safety guide for oil tankers and terminals

SHIPBOARD SYSTEMS

Section 11.8.3.1 gives guidance on special precautions to be taken in the
event of a breakdown of the inert gas system when loading static
การศึกษาเท่านั้น---
accumulator oils into inerted cargo tanks.

7.1.12.2 Follow-up Action on Crude Oil Tankers
งานห้องสมุด ศูนย์ฝกพาณิชย์นาวี
Pyrophoric iron sulphide deposits (pyrophors), formed when hydrogen
sulphide gas reacts with rusted surfaces in the absence of oxygen, may
be present in the cargo tanks of crude oil tankers and these deposits can
heat to incandescence when coming into contact with air. In the case of
tankers engaged in the carriage of crude oil, the failed inert gas system
must therefore be repaired and restarted, or an alternative source of inert
gas provided, before discharge from inerted tanks is resumed. (See also
Section 2.6.3.)

7.1.12.3 Follow-up Action on Product Tankers
Tank coatings usually inhibit the formation of pyrophors in the cargo tanks
of product tankers. If it is considered totally impracticable to repair the
inert gas system, discharge may therefore be resumed with the written
agreement of all interested parties, provided that an external source of
inert gas is provided or detailed procedures are established to ensure the
safety of operations. The following precautions should be taken:
The manual referred to in Section 7.1.12 above should be consulted.
satisfactory condition. ึ
Devices to prevent the passage of flame or flame screens (as
appropriate) are in place and are checked to ensure that they are in a

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Valves on the vent mast risers are opened.
No free fall of water or slops is permitted.
No dipping, ullaging, sampling or other equipment is introduced into
the tank unless essential for the safety of the operation. If it is
necessary for such equipment to be introduced into the tank, it should
be done after at least 30 minutes have elapsed since the injection of
inert gas has ceased. (See Section 7.1.6.8 for static electricity
precautions relating to inert gas and Section 11.8 for static electricity
precautions when dipping, ullaging and sampling.)

All metal components of any equipment to be introduced into the tank
should be securely earthed. This restriction should be applied until a
period of five hours has elapsed since the injection of inert gas has
ceased.

7.1.13 Inert Gas Plant Repairs

As inert gas causes asphyxiation, great care must be taken to avoid the
escape of inert gas into any enclosed or partly enclosed space.

No one should be allowed inside the scrubber or deck water seal until the
atmosphere has first been tested and an oxygen level of 21% by volume
obtained (see also Chapter 10 – Enclosed Space Entry). In addition, while
personnel are working inside the scrubber tower, the atmosphere must be
continuously monitored for oxygen content and the personnel should be
under constant supervision.

© ICS/OCIMF/IAPH 2006 101