Lesson 3. Fire Prevention in the Engine Room

FIRE PREVENTION IN THE ENGINE ROOOM

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.

Two basically different types of equipment are available on board ship for the control of fires. These are small portable extinguishers and large fixed installations. The small portable extinguishers are for small fires which, by prompt on-the-spot action, can be rapidly extinguished. The fixed installation is used when the fire cannot be fought or restrained by portable equipment or there is perhaps a greater danger if associated areas were to be set on fire.

The use of fixed installations requires evacuation of the area containing the fire which, if it is the machinery space, means the loss of effective control of the ship. Various types of both portable and fixed firefighting equipment are available.

Fire protection on ships is provided by detection and fire-fighting equipment together with structural features which are intended to contain an outbreak of fire and the employment when required of non-combustible materials to prevent its spread. 

Fire is the result of a combination of three factors:  a substance that will burn, an ignition source, 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, B and 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.

There are four principal types of portable extinguisher usually found on board ship. These are the soda-acid, foam, dry powder and carbon dioxide extinguishers.

A variety of different fixed fire-fighting installations exist, some of which are specifically designed for certain types of ship. A selection of the more general installations will now be outlined.

1. Fire main system for cargo ships

2. Automatic water spray & water mist system for machinery protected area

3. Automatic foam induction system for machinery space fire

4. CO2 fire extinguishing installations for machinery spaces

5. Inert gas systems, inert gas generator

6. Fire fighting Halon system

Machinery spaces are protected by fixed fire extinguishing installations, the fire main and extinguishers. Any statutory fixed installation must be operable from a position outside of the space. Any emergency stops for machinery and vent fans, means of securing openings and fuel tank valve shut-off devices, must also be located external to the space. 

Engine room fires have been started by neglected oil leaks with the combustible material, in the form of fuel or lubricating oil dripping on to and being ignited by hot exhaust manifolds. There are a number of examples of combustible materials and potential ignition sources in machinery spaces.
A fire when it starts is usually small enough to be dealt with by a vigilant watchkeeper using a portable fire extinguisher. A fire which develops undetected in an unmanned machinery space (or one where the watchkeeper is in a control room) could require complete shutdown, evacuation and employment of the inert gas system. With unmanned spaces, an efficient alarm system for early detection is vital. 

I. Answer the questions.

1. What is the most frequent reason for a fire?

2. What types of fire-fighting equipment are used on board ships?

3. What does the use of fixed installation require?

4. How is fire prevention provided on board ships?

5. What are the three factors which result in a fire?

6. What can ensure that a fire never starts?

7. How are fires classified?

8. What are the three stages of fire fighting at sea?

9. What are the types of portable extinguishers?

10. How are fixed fire-fighting installations operated?