The frequent occurrence of hazard caused by fire in market, residential apartment and shopping malls has posed a lot of threat to the economy of the nation. Some years back, statistics revealed that about 185 lives were lost to fire accident in Nigeria (where I reside) while property valued at #5.95 billion were lost to fire accident.
It is on this note that this write up is coming up so as to educate on safety measures to prevent fire hazards.
Hence, it is important to know what fire is and what can lead to fire.
What is fire?
Though fire is known as a thing, but fire is more than physical thing. Fire is a physical product of an exothermic chemical reaction called combustion. The reaction occurs when a combustible material (fuel)/ react with an oxidizing agent (usually oxygen) to release heat energy
Oxygen + fuel -------> combustion
The fuel must be heated to a temperature to produce sufficient vapour to become flammable. The gas molecules then combine with oxygen in the air to result in combustion. The combustion that result in flame is called burning. Therefore, the three element needed for flame to be produced
are heat, fuel and oxygen. This is known as fire triangle. The fire intensify as long the three component of the triangle is in place.
However, further research shows that three sides of the triangle is not complete without putting the fourth component and this leads to the discovery of fire tetrahedron
Fuel + heat + oxygen + combustion = fire
If any of these four is eliminated then the fire can be extinguished.
Oxygen ------------- Sustains combustion
Heat ------- ------ Raises the material to ignition
Fuel----------------- The combustible material.
Combustion ------ An exothermic chemical chain reaction.
Having established the process that leads to fire, it is important to understand the different classes of fire that exist. The fuel in the fire tetrahedron classifies fire into six classes.
CLASSES OF FIRE
CLASS A---caused by combustible material like paper, wood and textile.
CLASS B----caused by flammable liquids like petrol.
CLASS C---caused by gases like hydrogen and methane.
CLASS D----caused by metals like aluminium and magnesium.
CLASS E----caused by electrical equipment (removal of electrical item can change the class of the fire).
CLASS F----caused by cooking oil.
FIRE EXTINGUISHERS
Fire has a lot of purpose but it is also associated with risks. In case fire gets out of control, the class fire now determines the fire extinguishers to use. Fire extinguishers are safety tools and specialized equipment that are used in putting out different classes of fire. There are five main types of fire extinguishers
- water extinguishers -- This is for class A fires. This type of extinguishers work by creating a cooling effect on the fuel. The fuel then burn at slow rate until the flame is extinguished. The label colour of water extinguishers is red
- Foam extinguishers-- Used for class B fires but can also work for class A fires. Foam extinguishers also works by introducing a foaming agent between the flame and the fuel so as to extinguished the fire. The label colour is cream
- Standard dry powder extinguishers---They are also called ABC powder because they can tackle class A,B and C. This type of fire extinguisher is not recommended for enclosed place, this is to avoid inhalation of the powder. The label colour of standard dry powder extinguisher is blue
- Carbon(iv)oxide extinguishers---These are used mainly for electrical fire risk but they can also be used for class B fires. It works by displacing oxygen in the tetrahedron. The label colour is black. All vehicles should carry Carbon(iv)oxide extinguishers.
- Wet chemicals extinguishers---For class F fires. It creates foam on the surface of the burning oil. It also prevent oxygen from getting to the burning oil. It should be in canteens and kitchens. The label colour is yellow.
It is important to note that using wrong extinguisher for a particular class of fire may cause more havoc than planned for.
Conclusion
Fire can be a good servant, if the safety rules are well followed but at a point where it becomes a master the effect includes hazard to life and property. Therefore, fire safety is everybody's business.
Thanks a lot for taking time to read.
Please note that all the images are from free source free to use or share, even commercially
Refrences
A_Risk_Analysis_Model_for_Fire_Disasters_in_CommercialComplexes_in_Nigeria