Page 113 - International safety guide for oil tankers and terminals

Chapter 5
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FIRE-FIGHTING

Fire requires a combination of fuel, oxygen, a source of ignition and a continuousย์นาวี

This Chapter describes the types of fire that may be encountered on a tanker or at
a terminal, together with the means of extinguishing them. Descriptions of fire-fighting
equipment to be found on tankers and in terminals are provided in Chapters 8 and
19 respectively.

งานห้องสมุด ศูนย์ฝกพาณิช
5.1 Theory of Fire-Fighting

chemical reaction, commonly referred to as combustion.

Fires are extinguished by the removal of heat, fuel or air, or by interrupting the chemical
reaction of combustion. The main objective of fire-fighting is to reduce the temperature,
remove the fuel, exclude the supply of air or interfere chemically with the combustion
process with the greatest possible speed.

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5.2 Types of Fire and Appropriate Extinguishing Agents

The classification of fires given below is that historically provided in ISGOTT. It
conforms to the classifications used within Europe. Alternative classifications may be
used elsewhere.

5.2.1 Class A – Ordinary (Solid) Combustible Material Fires

Class A fires are those involving solid cellulosic materials such as wood, rags,
cloth, paper, cardboard, clothing, bedding, rope and other materials such as
plastic etc.

Cooling by large quantities of water, or the use of extinguishing agents
containing a large proportion of water, is of primary importance when fighting
fires involving ordinary combustible material. Class A materials can support
deep-seated and smouldering fires long after visible flames are extinguished.
Therefore, cooling the source and surrounding area should continue long
enough to ensure that no re-ignition of deep-seated fires is possible.

5.2.2 Class B – Fires Involving Flammable and Combustible
Hydrocarbon Liquids

Class B fires are those that occur in the vapour/air mixture over the surface of
flammable and combustible liquids such as crude oil, gasoline, petrochemicals,
fuel and lubricating oils, and other hydrocarbon liquids. Fires involving
flammable gases are generally included in this classification.

These fires are extinguished by isolating the source of fuel (stopping the flow
of fuel), inhibiting the release of combustible vapours or by interrupting the
chemical reaction of the combustion process. Since most Class B materials
burn with greater intensity and re-ignite more readily than Class A materials,
more effective extinguishing agents are generally required.

© ICS/OCIMF/IAPH 2006 79