Marine Engine Room Fire Protection Systems

The engine room of a seagoing ship is a very fire prone area. It houses about 130 different types of machinery with their associated risks. It also houses numerous tanks of heated fuel oils, lubricating oils, diesel oil, greases, and chemicals, etc. An average size ship consumes about 40 tons of fuel oil in a day; the same amount is pumped from the double bottom tanks, and is heated, filtered, allowed to sediment, purified, clarified, conditioned, reheated, and sent to the main engine for combustion. Heated fuel oils range in temperature as high as 120 to 150 degrees Celsius. It runs in kilometers of piping and often at a pressure as high as 1200 bars (in high pressure pipes during injection for a short length).

The engine room houses machines like steam boilers used for the production of steam for heating fuel oil, accommodation, and cargoes, where fuel is burnt inside in a furnace in controlled combustion. Incinerator wastes like oily rags, sludge, and other operational wastes are burnt at a temperature of 850 degrees C and above. Thus all these types of machines with their devices and piping can cause a fire hazard if not properly maintained, or if there is an automation failure, fatigue of material, or vibration failure. A fire in the engine room, unless restricted in the initial stages often goes out of control, causing many times the loss of the ship and life. Thus it is imperative that the machineries and the fire detection and firefighting systems are maintained in efficient condition.

Fire results from the combining of three factors:

1. A combustible substance.

2. A source of ignition.

3. A supply of air.

These three factors are said to be the three sides of the fire triangle. Removing any one or more of these sides will break the triangle and result in the fire being put out. The complete absence of any one of the three will ensure that a fire never starts.

The first side of the triangle, the substance that can burn, is in abundance in engine room- tanks of oil, pipes full of oil, oily rags, etc. This side can be removed by good housekeeping in the engine room, efficient garbage management, good maintenance of pipes, flanges, gaskets, and machines, etc.

The second side of the triangle, air, is also in abundance as huge engine room blowers pump air into the engine room for ventilation, cooling, and for combustion in the main and auxiliary engines, boilers, and incinerators.

The third side of the fire triangle is the ignition source, which can also be present sometimes due to failure of material or insulation, or due to human error. Lots of hot work is done in the engine room, like gas-cutting and electric arc welding. Hot work done without a valid hot work permit and without the attendance of a senior engineer is inviting trouble. The engineers must make sure that high temperature area like exhaust manifolds are insulated and that the insulation is in good condition. Frequent fires have been caused by fuel spilling from a leaking pipeline on to a hot surface and catching fire. Naked flames like butane lighters and cigarettes should be avoided in the engine room because of the presence of oil vapors. Smoking should only be done in designated areas like the engine control room, which is the certified smoking area. Also ill-maintained machines can cause hot spots and lead to subsequent fires. A badly maintained main engine can have a crankcase explosion and scavenge fire which can lead to a total engine room fire.

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