10 Safety Precautions To Take While Handling Inert Gas System On Ships
1. Ensure Proper Maintenance of Inert Gas Safety Devices is Carried Out
Safety devices on IG systems are used to prevent the backflow of cargo gases to the machinery spaces. It is important that along with the non-return valve, a water seal and a vent is also fitted on the deck main for additional safety.
Sometimes an additional water seal is fitted at the bottom of the scrubber. It is important that these devices are properly maintained at all times.
2. Ensure Adequate Oxygen Level
Oxygen deficiency is extremely hazardous to the human body. It can not only damage the brain but can also lead to death easily.
In case of oxygen deficiency, the mind is likely to become apathetic and complacent and if escape is attempted at this stage, physical exertion will aggravate the weakness of the mind and body.
For this reason, it is necessary to ventilate the cargo tanks thoroughly to ensure that no pockets of oxygen deficiency remain and a steady reading of 21% is obtained at all times.
3. Ensure There are no Combustible Gases
An important point to note is that the inert gas does not affect the toxicity of hydrocarbon gases and thus the latter can be extremely dangerous (as it is flammable).
Gas freeing of tanks must be properly carried out to eliminate possible gas pockets. Any particular compartment must show a reading of Zero or 1% of the lower flammable limit (LFL) with a reliable combustible gas indicator.
4. Remove Toxic Components of Flue Gases
An approved combustible gas indicator should be used to measure the presence of flue gases in the tank. Flue gases contain sulphur dioxide, carbon monoxide and nitrogen which need to be properly measured during the gas freeing process.
5. Check Tank Pressure
Check the tanker pressure before opening any tank lids, ullage plugs or tank washing openings. Inerted cargo tank pressure must be adequately reduced before opening any tank.
6. Prevent Air From Entering the System
In the event of an inert gas system failing to deliver the required quality and quantity of inert gas, or is not able to maintain a positive pressure in the cargo tanks, action must be taken immediately to prevent air from being drawn into the tanks.
All cargo and 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 other immediate actions must be taken to repair the inert gas system.
7. Take Measures to Prevent Electrostatic Ignition
The presence of hydrocarbons in the tanks can be dangerous. If the tank atmosphere contains flue gas, which has small particulate matter containing a small electrostatic charge, there is a possibility of an electrostatic ignition when the oxygen content of the tank rises due to the ingress of air.
Prevent any kind of ingress of air in the tanks.
8. Don’t Start Repair Work Without Gas Freeing
As Inert gas is asphyxiating, a person can quickly become unconscious even if the leakage of the gas has taken in the open air.
Extra precaution is thus required while doing any maintenance/repair work on the IG plant.