fire, direct attack, volatile oil fires, combustible, portable fire extinguisher, engine room, boundary cooling, radiant heat, hose nozzles, foam, oil fire, firefighters, valves, fire damage, flooding, carbon dioxide

Direct Attack of Fire

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fire, direct attack, volatile oil fires, combustible, portable fire extinguisher, engine room, boundary cooling, radiant heat, hose nozzles, foam, oil fire, firefighters, valves, fire damage, flooding, carbon dioxide

Direct attack of fire

Whenever somebody discovers a fire on board ship, the first thing for him to do is to alert people so that more help becomes available. At the same time, with a portable fire extinguisher he has to quickly make use of it to put out the fire.

However, with the volatile and highly combustible nature of some cargo or fuel, very often the fire will spread quickly. Portable fire extinguishers will then become no match for these types of fire.

Probably the most vulnerable place for fire to start will be the engine room. As we have seen in another page, the fire triangle is ever present in the engine room. There are plentiful supply of combustibles, strong heat source and of course, oxygen in the air, or even in gas cylinders.

Having to deal with these types of big or medium sized fires is therefore a strong possibility. Short of the last resort of flooding the whole engine with carbon dioxide, or foam or even water sprays, which, incidentally will mean massive destruction of the machinery in the engine room, the ship's officers and engineers must know what to do if such a fire occur on board.

Usually, they will split into 2 teams. One team will go directly to attack the fire and try to bring it under control. Another team will do boundary cooling to prevent the heat from one compartment to travel to another compartment thereby spreading to the whole ship.

A most likely scenario will have the engine personnel attacking the fire at the source, (most likely to be in the engine room) and the deck personnel doing the boundary cooling from the deck or cargo hold.

For those people who are directly attacking the fire, they have to protect themselves from the tremendous radiant heat of the fire while at the same time try to cool down the fire by water jets.

The attacking team therefore has to approach the fire in two groups. One group will adjust their hose nozzles to form a spray pattern, also called "water wall" while another group will follow behind the water wall (and so be protected from the radiant heat) with jet nozzles that can be directed to the seat of the fire.

As the pressure from the hoses are very strong, they will need at least 2 persons for one group in order to control the hoses.

On some ships, foam liquid could be mixed with the water in order to fight oil fires effectively. The action of foam is to blanket and starve the fire of oxygen. If water is used alone it must be used carefully in order not to worsen the spread the fire. This is because oil floats on water and the burning oil may thus spread with the water flooding the place.

The action of water in extinguishing the fire is by cooling. Sometimes it is better to break up the water jet by shooting above the fire and letting the water drop and cool down the fire in a fine mist.

When people are attacking the fire so closely, some way has to be made to divert all the smoke away from the firefighters. Most likely, some manhole, window or skylight will have to be opened up away from the firefighters.

In such incidents of fire, the quick-closing valves for all the oil tank outlets will be closed remotely from the deck. This is to prevent adding more fuel to the fire.

The fire fighting water piping installations on board ship will also have isolating valves that can be used to isolate certain portions that have been damaged by the fire. By closing these valves to the damaged portion of the piping, the pressure of the hoses can be maintained.

Even when there is a blackout caused by fire damage to electrical cables or generator sets, there is still an emergency fire pump driven by diesel engine available. This pump unit is usually located far away from the engine room, usually near the steering room at the stern of the ship. The engineers can start this pump engine by manual cranking.

With all these carefully thought out system in place and well-trained personnel, most medium-sized fire could be put under control and extinguished.

However, if these fail, there is no other choice but to do a total flooding of the engine room. This is the last choice because if this fails to extinguish the fire, there is no second chance left.

Total flooding of carbon dioxide system usually means getting all personnel out of the engine room, closing all the doors, skylights, ventilation fans, openings and discharging carbon dioxide gas into the engine room space... and waiting patiently. Patient enough not be tempted to open the door to look inside. There is a good reason for this. Once a door is opened, oxygen will enter and the fire may start again and there is no more carbon dioxide left to flood again.

The pictures show personnel being trained to use water wall spray to protect against the radiant heat of the fire

 

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