What is fire?

Fire is the rapid oxidation of a material in the exothermic chemical process of combustion, releasing heat, light, and various reaction products.

Classification of Fire :

There are six classes of fire

• Class A Fires – combustible materials: caused by flammable solids, such as wood, paper, and fabric
• Class B Fires – flammable liquids: such as petrol, turpentine or paint
• Class C Fires – flammable gases: like hydrogen, butane or methane
• Class D Fires – combustible metals: chemicals such as magnesium, aluminum or potassium
• Electrical Fires – electrical equipment: once the electrical item is removed, the fire changes class
• Class K Fires – Kitchen Fire

Which Fire Extinguisher Types Are Used For Each Class of Fire?

Types of Fire Extinguishers

1. Water & Foam: The water component of this extinguisher removes the heat of the fire, while the foam component removes the oxygen.

• Works For: Class A fires only

2. Carbon Dioxide: It replaces the fire’s oxygen and, as the gas is contained under pressure it creates a cold discharge upon release, which removes the heat of the fire too.

• Works For: Class B and C fires

3. Dry Chemical: This extinguisher removes the chemical reaction of a fire, and is the most used of all fire extinguishers because of its versatility across multiple classes.

• Works For: Class A, B and C fires (multi-purpose); Class B and C (ordinary)

4. Wet Chemical: This extinguisher removes heat and creates a barrier between oxygen and fuel so a fire cannot be re-ignited. The chemical is sprayed as a mist, cooling the fire’s heat and creating a blanket effect over the fuel.

• Works For: Class K fires (particularly good for fires started by oils or fats)

5. Clean Agent: Also called Halogenated extinguishers, these include halon agents and new, less ozone depleting halocarbon agents, which extinguish a fire by interrupting its chemical reaction.

• Works For: Class B and C fires

6. Dry Powder: This works similarly to the dry chemical extinguisher as the powder separates the fuel from oxygen or removes the heat, but this extinguisher is only used to fight combustible metal fires.

• Works For: Class D fires

7.Water Mist: This extinguisher takes away the heat of the fire only.

• Works For: Class A and C fires

8. Cartridge Operated Dry Chemical: This extinguisher interrupts the chemical reaction of the fire, and creates a barrier between the oxygen and the fuel and, like the dry chemical extinguishers, works well on a variety of fire types.

• Works For: Class A, B and C fires

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