Do you know the different classifications of fires?

Do you know the classification of fires plays an important role to enable the use of the correct method in extinguishing them?   

Fires are classified into four main types: those in solids, e.g, wood, paper, and cloth; those in flammable liquids, e.g. gasoline, alcohol, oils, lacquers, and paints; those in electrical apparatus; and those in flammable metals such as magnesium.  These are called respectively class A,B,C and D Fires.  A Fire Fighter would typically undergo training to be able to perform his/her duty as a health and safety representative and part of the health and safety team. Companies are obliged by the law to have at least one trained fire fighter on site at all times.

Methods of Extinguishing a Fire

Since the birth of fire fighting techniques back in Roman Times, water has been the principle weapon in the fight against uncontrolled fire. Even today, the vast majority of outbreaks of fire are quelled with water.

However, as the modern age has brought more hazardous flammable materials and substances into common usage, so the fire industry has developed more sophisticated extinguishing methods.

Flammable liquid fires, such as petrol, Aviation fuel and diesel oil, led to the introduction of foam compounds. When mixed with water in the right proportions and aspirated, fire fighters can lay a foam carpet of varying thickness over the surface of burning fuels or oil, cutting off the oxygen supply that is necessary for a fire to burn. Various foam densities are available, depending on the nature of the fire involved. Similarly, finely divided powder has the same smothering effects as foam, while compressed carbon dioxide gas is used to control outbreaks of fire in electrical installations.

Other man-made chemical mixes are used in small extinguishers to protect against vehicle fires. In the home a simple fire blanket can be the best protection for such emergencies as chip-pan fires.

Interestingly, many modern fire pumps use water at a very high pressure to produce atomised fire fighting water ‘fog’ dispensed through small diameter hose reels wound on drums on a pump. This gives a very powerful cooling effect, yet uses much less fire fighting water than traditional jets. It also has the advantage of minimizing water damage to the fabric and contents of the affected building.

Water fog is ideal for one-room fires but one does require care in its use to prevent a flashback when the fire re-ignites. To deal with serious fires there is usually no substitute for large water jets, many of which can each project up to 1136 liters per minute into an inferno.

But the real secret of fire fighting effort lies in finding the seat of the fire. Crew in breathing apparatus have a battle into the heat and smoke inside a building before getting water directed onto the flames at close quarter. Ventilation of the smoke produced by a fire is also a vital part of fire fighting strategy. Allowing hot gases to escape through windows or holes cut in a roof obviously makes the lot of the fire crew inside considerably easier and safer. Yet ventilation must be carefully timed to coincide with fire fighting operations; if done haphazardly it can feed a fire and at worst, create a ’flash-over’, with possible fatal results.

For a fire to occur, there must be available oxygen, a supply of fuel, and enough heat to kindle the fuel. Therefore, the three basic ways of extinguishing fire are to smother it, to cut off the fuel supply, or to cool it below the flammability temperature.
These three principles are:

The Extinguishing of fire by starvation is applied in three ways.
Removing combustion material from the neighbourhood of the fire. Examples of this:
The draining of fuel from burning oil tanks
The working out of cargo at a ship fire
The cutting of trenches in peat, heath and forest fires.
The demolition of buildings to create a fire stop
Counter-burning in forest fires
Removing the fire from the neighbourhood of combustible materials for instance, pulling apart a burning haystack or thatch roof.
Subdividing the burning material when the smaller fires produced may be left to burn out or to be extinguished more easily by other means.

A typical example is the emulsification of the surface of burning oil, whilst the beating out of a heath fire owes much of its effectiveness to this.

If the oxygen content of the atmosphere in the immediate neighbourhood of burning material can be sufficiently reduced, combustion will cease, for example when throwing a blanket over something that is burning or throwing sand on a fire.

The general procedure in methods of this type is to prevent or impede the access of fresh air to the sweat of the fire and allow the combustion to reduce the oxygen content in the confined atmosphere until it extinguishes itself.

There are instances when this will not work. E.g. when celluloid is burning. In this case the material that is burning (celluloid) contains within itself in a chemical combines form, the oxygen it requires for combustion.

If the rate at which heat is generated by combustion is less that the rate at which it is dissipated through various agencies, the combustion cannot persist.

In applying this principle of fire extinguishing, the first step is to accelerate the speed with which heat is removed from the fire, ths reducing the temperature of the burning mass and as a consequence, the rate at which the heat is produced.

In due course the rate at which heat is lost from the fire exceeds the rate of heat production and the fire dies away.

What all this means is that, when you take away enough heat from the fire, the fire will die. An example of this is throwing water on a fire.

Once any one or more of the elements is removed the fire will be extinguished.

Companies are obliged by the law to have at least one trained fire fighter on site at all times for every 50 employees they have. Having employees attending a Basic Fire Fighting Training is the first step to be compliant. Basic fire fighting training is offered to assist employees who are tasked with the responsibility of fire-fighting activities in the workplace. It is meant to assist them execute their duties in the safest and most appropriate manner and to lay the foundations that professional fire fighters can use to kill a fire.

The Basic Fire Fighting Training course introduces learners to the basics of preventing and fighting fire. It further educates them in-depth about fire fighting.
The content of the training should take the learner step by step from introduction up to the last step of dealing with a fire itself. Student fire fighters are introduced to the various kinds of fires he is dealing and the action that should be taken for each type of fire.

Basic Fire Fighting Training
Basic Fire Fighting Training
The basic fire fighting training course assists you to:
a) Identify different types of fire
The learner must be trained about the chemistry of fire, spread of fire and heat radiation. In addition, a learner will know how to classify different fires according to their causes.
b) Know how fire prevention can be done
Aspects to be discussed are fire prevention and protection, fire-fighting and safety equipment, fire causes and problems that may hamper fire control. Also a learner will be educated on how to prepare for an emergency and implement evacuation procedures.
c) Choose the right equipment for extinguishing different fires

Different fires can be effectively controlled by certain fire extinguishing methods. A basic fire fighter should be in possession of such knowledge.
d) Know how to operate basic fire fighting equipment.
Examples of basic fire fighting equipment are fire extinguishers and fire blankets.
e) Methods of extinguishing fires
f) Monitor and respond on time on changes on fire
g) Contain and/or extinguish fire

It is essential for Basic Fire Fighting Training to be provided by methods of both theory and giving learners an opportunity to perform practical exercises. No fire will ever develop according to the book.
Basic fire fighting training can have companies resting assured that in cases of fire emergencies, they are equipped with knowledge employees who will act quickly and efficiently. The last thing they need is having an acceleration of the fatality due to lack of knowledge on procedures to be followed.
When you need to meet health and safety compliance standards by having your staff trained to fight fires, MAKROSAFE is certainly able to assist you. Their training services include, not only basic fire fighting training but, a whole wide scope of training in all health and safety aspects. Training is provided through facilitator presentations, individual and group activities and discussions ad skills application. MAKROSAFE provides training in all regions of South Africa.

For all your Fire requirements and Training, contact us today at My Safety Shop



Posted date: 25th Feb 2019
Health-&-Safety-Services - General Health and Safety - Health and Safety Training - Occupational Health - Health and Safety Programme