Water mist fire fighting system has been discussed in this article and we will study that in detail. As name suggest water mist system fights fire by cooling down the fire with the help of very fine water droplets also called hyper mist. On different ships, you have might have water mist or hyper mist. Later one is more advance system.
Over the years, water mist fire fighting system has gained a lot of name as it is easy to maintain and running costs are less. System uses fresh water from the tanks onboard and uses set of nozzles to spray water in fine form or droplets. We will cover our topic in three heading which are given below:
- What is water mist system
- How does it work
- Maintenance regarding this system
What is Water Mist or Hyper Mist
Mist is generally related to the very fine form of liquid, can be oil or water or anything. Evening the crankcase the oil mist is there. So, whenever the liquid is so like that it breaks into very fine form, it turns in to mist. A very easy example is the mist formed by the garden sprayer or sprinkler.
Now the term hyper mist comes from the fact that, the water is disintegrated in to such fine particles that it almost looks like a gas (literally). If you see a hyper mist working in on ship, the droplets are so fine that it looks like there is a cloud of water all around you.
Such system is installed on ship and protects the critical machineries like main engine, generators, boilers and purifier room. Or you can say the place where the chances of fire are too much. So, it does not cover the whole engine room.
Now since you have the idea of mist, we will move on to our next heading which is called as how does this system work. We will include diagram also, so that it become very easy for you to understand.
How does water mist fire fighting system works?
Well let’s understand this with a diagram which we have found out. Whole system consists of water tanks, pumps, nozzles and fire detector heads.
Pumps are two in number and they take suction from the fresh water tanks. Also, fresh water tanks have inbuilt alarms system which triggers if water level is low in the tank. There is a line from the sea water also, but that is like a back up only (in case you run out of fresh water). Advantages of fresh water are that corrosion problems related to the pipes are minimized a lot.
After the, there is a solenoid for each line which open the valve and lets the water go on to the section where there is a fire. After this, at the ends there are spray nozzles, which transforms water into very fine spray. This way the surface area of the water increases and the heat absorbing capacity increases a lot. Also less amount of water is used as compared to tradition sprinkler system.
So if there is a fire in an area, one fire detector will send a pre-warning signal. If another fire detector gets activated, then the pump will get a signal to start, and the solenoid will open for such location. It will keep on running till around 20 minutes, until it stops.
This system can be activated locally for each section and also remote also (outside engine room).
Maintenance on Water Mist Fire Fighting System
This system does not require much maintenance as compare to other fixed fire fighting system. But here are some of the maintenance that you need to carry out.
- Check the strainers before the pump are clean
- Check pump for operation every month, by testing one section every month.
- After testing, blow the system with air, so that no water remains in the pipe.
- Check nozzle spray and clean if necessary
- Check the operation of solenoid.
- Check the pressure developed by the system
- All control and automation to be checked for normal working conditions.
- Check low pressure alarms and standby start of other pumps as well.
- Check all audio and visual alarms.
- Alternate checking from local as well as remote to be carried out every month.
This was all from the article on ‘Water Mist Fire Fighting System’. Hope you enjoyed reading it. If you anything to comment, please write us below.