Understanding fire classification and fire extinguishers

Fire is a powerful force of nature that has the power to both shape our world and bring it to its knees. According to SafeQuip,  a leading distributor of fire-related equipment, understanding the different types of fires and how to combat them is essential for safety and protection.

What is Fire and Its Elements?

Fire is a rapid chemical reaction between oxygen in the air and a fuel source, typically accompanied by the release of heat, light, and various gases. 

Classification of Fires

Fires are classified into different categories based on the type of fuel involved. 

Class A Fires: These fires involve ordinary combustible materials such as wood, paper, cloth, and plastics. 

Class B Fires: Class B fires are fuelled by flammable liquids or gases, including gasoline, oil, propane, and alcohol. 

Class C Fires: Class C fires involve energised electrical equipment, such as wiring, appliances, and electrical panels. 

Class D Fires: Class D fires consist of combustible metals like magnesium, sodium, and potassium. 

Class F Fires: Class F fires are kitchen fires that involve cooking oils, fats, and greases. 

Lithium-ion Battery Fires:  Currently lithium-ion batteries do not have a separate fire class, but internationally extensive research is being conducted to clearly define such a category due to the risk involved with such fires. When lithium-ion batteries are damaged or become unstable they have the potential to overheat. This can result in a highly volatile fire that spreads rapidly (thermal runaway), has the tendency to re-ignite, and proves challenging to extinguish. Conventional fire extinguishers are ineffective in extinguishing lithium-ion battery fires.

Different Types of Fire Extinguishers

Selecting the right extinguisher can make a significant difference in controlling, suppressing and extinguishing fires effectively. 

Water Fire Extinguishers 

Water fire extinguishers are effective for Class A fires. Water cools the flames and removes the heat element from the fire triangle.

Carbon Dioxide Fire Extinguishers 

CO2 fire extinguishers are suitable for Class B and Class C fires. They work by displacing oxygen and cooling the fire.

Powder Fire Extinguishers 

Powder fire extinguishers are effective for Class A, Class B, and Class C fires. They contain a dry chemical powder that smothers the fire by interrupting the combustion process.

Foam Fire Extinguishers

Foam fire extinguishers are ideal for Class A and Class B fires. They create a layer of foam that seals the surface, smothers the flames, and prevents re-ignition.

Wet Chemical Fire Extinguishers

Wet chemical fire extinguishers are designed for Class F fires. They use a special potassium-based solution to cool and suppress the fire, while also reacting with the fats to form a soap-like substance that seals the surface.

Lithex-Ex Fire Extinguishers

Lithex-Ex Fire Extinguishers contain AVD – an agent specifically designed for lithium-ion battery fires. AVD is made from the naturally occurring mineral vermiculite combined with water. It is a very effective agent that, cools, encapsulate, prevents propagation, prevents re-ignition and extinguishes lithium-ion battery fires. The AVD is applied as a mist and the water content knocks down the flames and cools adjacent cells. As the water evaporates, AVD forms a film over the cells, isolating the fuel source, reducing thermal propagation and acting as oxygen barrier.