• A tank (half filled with fresh water) initially charges the entire system with fresh water at a pressure of about 8 bar and maintains it under pressure with compressed air.
• It is also connected to an independent seawater pump with its own seawater suction. Each sprinkler head has a quartzoid bulb, which retains a diaphragm seal in the outlet of the water pipe.
• When the sprinkler head comes into operation, the non-return alarm valve for the section opens, and water flows to the sprinkler head. This non-return valve also uncovers the small bore alarm pipe lead, and water passes through this small bore alarm pipe to a rubber diaphragm. The water pressure acts on this diaphragm, and this operates a switch, which causes a break in the continuously live circuit. Alarms, both visible and audible, fitted in the engine room, bridge and crew space are then automatically operated.
• When the system pressure drops to 5 bar, the seawater pump will start automatically and continue to supply with seawater. A hose connection is also provided so that water can be supplied to the system from shore when the ship is in dry dock

After the firefighting system has used seawater, it's crucial to take specific actions to prevent corrosion and maintain system integrity. The primary action is to flush the entire system with fresh water. Seawater is highly corrosive, and leaving it in the pipes, valves, and sprinkler heads can lead to blockages and damage. The system should be drained and then thoroughly flushed with fresh water to remove all traces of salt and corrosive elements. After flushing, the system should be refilled with fresh water and re-pressurized to its operational state, ready for future use.