water mist fire detection Archives - Marine Engineering Study Materials

Testing of Water Mist Fire Fighting System onboard Ships

Operation test is carried out on water mist fire fighting system onboard ships for the verification of pump condition and pump discharge pressure.

The testing procedure is as follows.

All section solenoid valves must be in closed position and water supply valve to be kept open.
Open the pump drain valve.
Turn the select switch to manual in pump starter panel.
Start the pump.
Check the pump and discharge pressure.
Stop the pump.
Drain out the water from pump unit.

Close water supply valve.
Disconnect motor power cables.
Open air valve at the pump discharge. (For providing air to the nozzles instead of water).
Actuate both flame and smoke detectors in the relevant area.
Check the alarm at the control panel and repeater panel.
Check visual and audible alarm in the protected space (Engine Room).
Check the release of air from nozzles at the relevant area.
Push stop button from control panel.
Follow same testing for other sections.

Close water supply valve.
Disconnect motor power cables.
Open air valve at the pump discharge. (For providing air to the nozzles instead of water).
Press start button from control panel for the area to be tested.
Check the alarm at the control panel and repeater panel.
Check visual and audible alarm in the protected space (Engine Room).
Check the release of air from nozzles at the relevant area.
Push stop button from control panel.
Follow same testing for other sections.

Freshwater tank low level alarm can be tried out by manually lowering the float.

Electric source failure can be tested by removing fuse from the control panel.

The whole piping system to be blown through with compressed air at a pressure of 7 to 8 bar.

Check the free passage of air from the nozzles.

Drain out the water from all piping and make sure piping, wiring, and equipment is installed properly and ready for service.

Water mist discharge of 30 seconds is to be carried out for at least one section (as per DNV).

Pressure testing of water piping system to be done for at least 1.5 times maximum working pressure (as per DNV and KR).