Explain Sprinkler fire fighting system in a ship and how it is tested?

Testing procedure

 a. Close the section isolating valve, this will raise an alarm indicating zone isolation.

 b. Now, open the test valve, if no water comes out, then it means the NR valve placed after the section isolating valve is not leaking.

 c. Since, the section after the NR valve remains pressurized, opening of the drain valve will cause the water pressure in the section line to decrease. A pressure switch sensor senses the decreased pressure & raises an alarm. 

 d. Now, close the drain valve, open the section isolating stop valve. To check the flow switch, open the flow test switch to activate an alarm.

 e. All the above alarms will be indicated on the navigation bridge, E/room as well as in the Fire Control Room. The alarm will also indicate the particular zone from where it has risen.

  f. If all the alarm conditions are satisfied, close all the testing valves, open the section isolating valve, purge the sprinkler line by air and again keep the line pressurized. Check from the pressure gauge, that proper pressure has been maintained or not.