An explosion in a cargo tank, is one of the most serious situations that any Emergency Organisation can be called upon to fight. In the loaded condition there will probably be little that the Emergency Party can achieve, and the saving of life is of paramount importance.
In the ballast condition there may be a greater chance of taking some effective action.
The following points must be considered by the Master following such an explosion:
- Possible isolation of the resultant fire by the Emergency Party putting up a “water wall” around the periphery of the fire.
- Arresting the transfer of heat into adjacent accommodation spaces by spraying the poop front bulkheads etc.
- Bringing foam-making equipment into action.
- Evacuation of non-essential personnel.
- Adjusting the vessel’s course and speed as necessary to minimize fire spread and reduce further structural damage.
- The release of the fixed gas fire extinguishing medium into the cargo pump room to inert that space in order to prevent the spread of fire from the cargo tank or hold.
Before releasing the fixed gas extinguishing system in the pump room the Master must be satisfied that there is no chance of an explosion in the pump room (an explosimeter reading must not exceed 40% LEL). It must be remembered that electrostatic charge separation may occur at the CO2 nozzles.
This produces a possible source of ignition in the form of charged frozen particles of C02 in the pumproom.
Any possible action is to be dictated by circumstances (the ability to provide water on deck etc) but it is the duty of the Master and the Emergency Organisation to do all in their power to combat the situation, even after the non-essential personnel have left the ship.