There is some type of Fixed Fire Fighting Onboard arrangement to fight the fire. And in some cases, these arrangements are made for certain types of ships. This we are going to discuss here. Let’s start.
Fixed Fire Fighting Fire Main System:
This is a type of Fixed Fire Fighting Onboard system. We can see in every ship there will be a connection from the seawater supply system to the fire hydrant on the ship. For helping this, there are many pumps we can see in the engine room and also supply the system. Also, The capacity and the number of pumps used will decide by the authorised people. Also, for any emergency, there will be an emergency fire pump arrangement. It will locate in a remote place also away from the machinery spaces. And it will operate by the emergency power system.
There will be fire hydrants with the isolating valve is arranged in each part of the ship. Also, the appropriate hoses, connection and the nozzle will be there near the hydrant. The nozzle will be the type of jet or spray. This will help to spray the water in any of the two forms as we required. With this, the fire hydrant could cover each and every part of the ship. Also, we can supply a constant amount of seawater to put off the at any point onboard ship.
Also, the seawater is considered as the best cooling agent to fight the fire belongs to Class A. And it will also help to put off the class B fire. By using the jet or spray nozzle can help to put off the fire by emitting the water as a fine spray. This will help to cool the surface easily without spreading it. There will be an arrangement of international shore connection always on board ship. This connection is standard and helps to fit with a suitable coupling that suits the hose on the ship.
Fixed Fire Fighting Onboard Automatic Water Spray System:
This is a type of Fixed Fire Fighting Onboard system. We can see in some places of the ship will fit automatic water spray system or sprinkler system. This is a network of sprinkler above the head to spray the water automatically if fire detected. The places where the sprinkler is seen are accommodation spaces and machinery spaces. But in both places, the operation and some equipment may be different.
Such as in accommodation spaces the sprinkler system will fit with arrangements for detecting and extinguishing the fire as well. The head of the sprinkler will cover by a bulb-like an arrangement that contains some kind of liquid. This liquid will expand when it gets a certain amount of heat. When the heat rises to a certain limit, then the liquid will expand much. And this causes the breaking of the bulb. And then the water will come out through the sprinkler system. There will be an arrangement of a deflecting plate. This will help to spray the water to wide areas.
At the time of spraying the water first time, the water will supply from a pressure tank. After some time, the water will supply from a saltwater pump that works automatically to maintain the supply. The use of freshwater for the first time will avoid corrosion.
Related Article: Portable Fire Extinguishers Onboard Ship
Fixed Fire Fighting Onboard Inert Gas System:
This is a type of Fixed Fire Fighting Onboard system. The inert gas will use an onboard ship to avoid the fire presence. The inert gas will avoid the combustion process. Nitrogen and carbon dioxide will be more. This large amount of gas for extinguishing the fire will get from the fuel burning and also from the exhaust gas from the boiler.
Inert Gas Generator:
Some times we cant get the inert gas sufficiently from the exhaust of the boiler. At this time we will use the inert gas generator. The inert gas generator will burn the fuel in a certain amount and perfect combustion will take place. The combustion of the fuel will help to produce the inert gas with a combination of nitrogen and carbon dioxide. Also, the presence of oxygen in this gas combination will be very less.
After the production, this gas will pass to the washing chamber. There the gas will be cooled and the sulphur, excess amount of carbon will be removed. After this, the inert gas will pass to the distribution system to fight the fire.
Funnel Gas Inerting:
The funnel gas inerting arrangement is commonly seen in the tanker ships. In the tanker ships, the exhaust gas of the boiler system will take and clean as well as inerted. After this, the exhaust gas will be cleaned again by using a scrubbing tower. With that, the gas will make as dry and filtered. After that only the gas will move to the main distribution. This final gas will consider as inert because the percentage of oxygen in it will be 5.
After this, it will distribute to the various tanks with the help of deck pipes and fans. There will be a seal arrangement on the pipes to avoid the reverse flow of the gas. The tanks at the time of no-load will fill with inert gas. And the gas will remove at the time of loading the cargo. Also, the advantage of the funnel gas inerting system is that it can produce the inert gas continuously.
This is another type of Fixed Fire Fighting Onboard system. There we have two halogenated hydrocarbon gases use on ships to fight and extinguish the fire. The commonly used gases are Halon 1301 and Halon 1211. Normally the other gases will cool the fire and remove the oxygen content to extinguish the fire. But in the case of the halon gases, it will inhibit the reaction of the flame. Since the halon gas have low vapour pressure when it liquefied, we can store the liquefied halon gas in a low-pressure container.
Another advantage of using the halon gas is it is not toxic to the people. The storage system f the halon gas and the usage also is similar to the carbon dioxide system. To increase the speed of the discharge of the gas, the liquid halon gas should keep at a certain pressure with some amount of nitrogen in it. Also, there are bulk storage of halon gas and will use with compressed air to expel the gas. Since the halon system can be a reason for the ozone depletion, it has been banned by the IMO.
Related Article: Fire Fighting Procedures Onboard Ship.
Carbon dioxide System:
There is an arrangement to flood the spaces where the fire has been found with carbon dioxide to a certain level. Also, the design of the machinery spaces will help for the quick discharge of the carbon dioxide gas to the spaces. The place must evacuate and seal before sending the gas to space. There will be a discharge valve and a key near to space with a glass covering.
We can hear the alarm while we open the valve for discharging. When we operating the lever, the pressure cylinder will release and the operating cable will work. And this will cause to open all the cylinder. Then space will flood with carbon dioxide gas quickly. For checking any leakage in the cylinder, it must check the weight or measure the quantity of the gas.
Conclusion: Hope you got a clear idea about the working and construction of some fixed fire fighting system onboard the ship. Comment your opinion below.
Note: The Articles and the Images are should not to copy or reproduce without the permission of Marinewheel.