Page 134 - International safety guide for oil tankers and terminals

INTERNATIONAL SAFETY GUIDE FOR OIL TANKERS AND TERMINALS

conditions. However, in extreme cold conditions, residual water in the inert
gas may freeze in the inert gas main. Operators should be aware of this
---ใช้เพื่อการศึกษาเท่านั้น---
and should therefore operate the system to minimise residual water and
closely monitor the system’s operation.

งานห้องสมุด ศูนย์ฝกพาณิชย์นาวี
7.1.11.2 Control Air
Air operated control valves fitted to the inert gas system outside the
engine room may not operate correctly if exposed to extremely low
ambient temperatures if the control air has a high water vapour content.

Water separators in control air systems should be drained frequently and
the control air dryers should be checked regularly for efficient operation.

7.1.11.3 Safety Devices

In extremely cold weather, ice may prevent the pressure/vacuum valves
from operating and may block the flame screens on the pressure/vacuum
valves and mast risers.

Water filled pressure/vacuum breakers should be filled to the appropriate
level with anti-freeze liquid.

Deck water seals are fitted with heating coils and these coils should be
ึ
put into operation prior to experiencing cold weather conditions.
7.1.11.4 Sea Chests

To ensure that the water supply to the scrubber and deck seal is
maintained in ice conditions at sea or in estuaries, low sea water suctions
should be used. This will reduce the probability of ice slurry being drawn
into the sea chest. Steam injection connections to sea chests can be
used to assist in clearing sea chests, if it becomes necessary.

7.1.12 Inert Gas System Failure
SOLAS requires that each ship fitted with an inert gas system be provided with
detailed instruction manuals covering operations, safety and maintenance
requirements, and the occupational health hazards relevant to the installed
system and its application to the cargo tank system. The manual must include
guidance on procedures to be followed in the event of a fault or failure of the
inert gas system.

7.1.12.1 Action to be Taken on Failure of the Inert Gas System

In the event that the inert gas system fails to deliver the required quality
and quantity of inert gas, or to maintain a positive pressure in the cargo
tanks and slop tanks, action must be taken immediately to prevent any air
being drawn into the tanks. All cargo and or ballast discharge from inerted
tanks must be stopped, the inert gas deck isolating valve closed, the vent
valve between it and the gas pressure regulating valve (if provided)
opened, and immediate action taken to repair the inert gas system.

Masters are reminded that national and local regulations may require the
failure of an inert gas system to be reported to the harbour authority,
terminal operator and to the port and flag state administrations.

100 © ICS/OCIMF/IAPH 2006