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Safety Issues Related to Inert Gas (IG) Systems on Ships

written by: Ricky • edited by: Lamar Stonecypher • updated: 12/17/2008

The inert gas system on board ships might be essential for the safety of the ship but it does have some safety issues related to it as well. Learn about some important safety considerations associated with IG systems in this article

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    In the previous article we saw the appropriate concentrations of various elements in the tank atmosphere necessary for safe entry on a ship. Now we will see what other safety considerations are associated with IG plant such as back flow of gases, iron sulphide and so forth.

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    IG System Safety Considerations

    During Repair of IG Plant

    The inert gas plant certainly needs to be well maintained because of its important role on the ship but unless caution is exercised, this maintenance or repair work could be dangerous for human life. The personnel working on the IG plant need to be very cautious and the plant should be completely gas-freed otherwise any traces of inert gas could lead to loss of consciousness and ultimate death. In case the repairs of maintenance relates to internal parts of the plant such as the scrubber, all enclosed space entry requirements and precautions should be fully adhered to.

    During Handling of Tank Openings

    Sometimes the personnel might need to open some particular tank openings such as lids or plugs while the tank is in inert condition; adequate care should be taken for these procedures otherwise the relatively higher pressure inside the tank with respect to the atmosphere could cause physical damage during the process.

    Miscellaneous Hazards

    There could be several other situations which might cause problem and though it is not possible to list each and every such situation, one should always be alert and aware to prevent any possible developments which could lead to a dangerous situation.

    For example during the tank washing operation there might be excess of charged particulate matter which be dangerous if the atmosphere within the tank reaches flammable limits due to some reason or the other.

    Another possible hazard could be the formation of pyrophoric deposits if the crude oil is of a specific kind or has low amount of hydrogen sulphide content. Technically pyrophoric refers to a substance which could possibly self-ignite just in the presence of air containing sufficient level of oxygen hence the risk of the same can be perceived.

    A risk which could pose danger to the entire system and the ship is the backflow of hydrocarbon cargo gases from the IG distribution system to the IG plant located in the safe zone of the ship.

    Having taken a look at the various types of risks and hazards associated with the IG system, it is important to take the necessary precautions so that there is least possibility of the occurrence of any kind of accident. These accidents could occur either due to negligence and carelessness or due to lack of maintenance of the IG system and its components. Hence in the next article we will study about the maintenance aspect of the IG system of the ship.