FIRE FIGHTING AND SAFETY ON SHIP- Part 1

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Ref: Introduction marine engineering

Fire is a constant hazard at sea. It results in more total losses of ships than any other form of casualty. Almost all fires are the result of negligence or carelessness. Combustion occurs when the gases or vapours given off by a substance are ignited: it is the gas given off that burns, not the substance. The temperature of the substance at which it gives off enough gas to continue burning is known as the 'flash point'.

Fire is the result of a combination of three factors:
1. A substance that will burn.
2. An ignition source.
3. A supply of oxygen, usually from the air.

These three factors are often considered as the 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 one of the three
will ensure that a fire never starts. Fires are classified according to the types of material which are acting
as fuel. These classifications are also used for extinguishers and it is essential to use the correct classification of extinguisher for a fire, to avoid spreading the fire or creating additional hazards. The classifications use the letters A, B, C, D and E.
Class A Fires burning wood, glass fibre, upholstery and furnishings.
Class B Fires burning liquids such as lubricating oil and fuels.
Class C Fires burning gas fuels such as liquefied petroleum gas.
Class D Fires burning combustible metals such as magnesium and aluminium.
Class E Fires burning any of the above materials together with high voltage electricity.
Many fire extinguishers will have multiple classifications such as A, Band C.

Fire fighting at sea may be considered in three distinct stages, detection—locating the fire; alarm—informing the rest of the ship; and control—bringing to bear the means of extinguishing the fire.