Fuel, heat and oxygen are the three musketeers of Fire Triangle. Fuel which is the source when exposed to enough heat produces the fire, oxygen helps the fire keep growing. Although there are several different types of fire extinguishers, all work with the same concept of stooping the fire by eliminating one or more of the three elements.
Types of Fire Extinguishers can be classified by Material and Class.
5 classes of Fire Extinguishers: 1- Class A are used on ordinary combustibles substances like wood, cloth and paper.
2- Class B are used on inflammable liquids like fuel, grease and oil.
3- Class C are used on electrically generated fires, works by releasing bad conductor of electricity. 4- Class D are used on inflammable metals like aluminium, sodium and magnesium. 5- Class K are generally used for cooking and kitchen related fires.
Types of Fire Extinguishers classified by material
Water and Foambased Extinguishers This type of extinguishers works by eliminating the heat and separating oxygen from heat and fuel.Water extinguishers which is classifies as Class A cannot be used for B and C as there are chances of spreading the flammable liquid in Class B and for Class C, it is a good conductor of electricity.
Water Mist based Extinguishers They are provided with a nozzle that sprinkles tiny water particles to remove the heating element which ultimately helps in eliminating Class A cases. They can also be used in Class C as they are free from electric shocks.
CO2based Extinguishers CO2 based extinguishers contains a very cold discharge that helps in reducing oxygen levels and removing the heat. They can be used for Class B and Class C cases.
Clean Agent basedExtinguishers They are the environmentally friendly replacements for Halon Fire Extinguishers. They are stored as liquid but turn into gas when discharged into air. They can be used in Class B cases and are effective in Class C cases as they do not cause any damage to electronic equipment.
Dry Chemical based Extinguishers This type of fire extinguishers works by disturbing the chemical process that takes place during the fire. They are the widely used multi-purpose fire extinguishers that can work effectively on Class A, B and C cases.
Wet Chemical based Extinguishers Wet Chemical based extinguishersremoves the heat and constrains the oxygen level for further combustion to occur. They work with full effectively in stopping the Kitchen fires (Class K). They can also be used for Class A cases.
Dry Powder based Extinguishers They are classified as Class ABC as they are effective on all the cases. It is not recommended to use in enclosed rooms as the dry powder creates suffocation and also difficult to clean up. They can also be used for Class D cases.