ENGINE ROOM HYPER-MIST (HIGH-PRESSURE WATER FOG) FIRE FIGHTING SYSTEM

Auto mode:

• The system is fitted with smoke/ heat detectors in the protected space (engine room). When a detector senses a fire (smoke/ rapid temperature rise), it sends a signal to the control panel.
• The control panel, on confirmation (e.g. two detectors or a single detector with a time delay), automatically activates the system: it starts the high-pressure water pump(s), opens the section/ zone valves, and discharges high-pressure water through the mist nozzles in the affected zone.
• The high-pressure water (typically 60-100 bar) is atomised into a fine mist (water fog) that fills the space, extinguishing the fire by cooling, smothering (steam generation) and blocking radiant heat.
• The system also sounds the alarm and may shut down the ventilation/ fuel supply to the space.

Manual mode:

• The system can be operated manually from the control panel or from manual release stations (pull stations) located at the space entrances/ on the bridge.
• On manual activation, the operator starts the pump(s) and opens the zone valves to discharge the mist into the protected space.
• Manual operation allows the fire to be fought selectively (e.g. a specific zone) and is used when the automatic system has not activated or when the operator decides to act.

Isolation:

• Inform the watch/ duty engineer and obtain permission; prepare a permit-to-work/ risk assessment.
• Isolate the system: close the section/ zone valves, stop the pump(s), and isolate the power/ control supply to the system. Tag the system "isolated for maintenance".
• Depressurise the system (drain the high-pressure lines) as required.
• Ensure the protected space is safe (no fire risk) before isolating the system.

Tests and inspections:

• Inspect the nozzles for blockage/ damage and clean/ renew as required.
• Check the pump(s), the pressure, the control panel and the detectors for correct operation.
• Test the alarms and the automatic/ manual activation (functional test).
• Check the water supply/ tank level and the system pressure.
• Test the zone valves for correct operation.

Returning to service:

• Complete the maintenance, remove the tags/ locks, and re-energise the system.
• Refill/ re-pressurise the system and confirm the pressure is correct.
• Carry out a functional test (alarm, pump start, valve operation) to confirm the system is operational.
• Record the maintenance and the test, and inform the watch/ duty engineer that the system is back in service.