Fire Types and Extinguisher Mitigation Methods

 

Fires are classified based on the materials that fuel them, and different types of fires require specific extinguishing methods. Here are the main types of fires and how to mitigate them using appropriate fire extinguishers:

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1. Class A Fires: Ordinary Combustibles:

• Materials Involved: Wood, paper, cloth, rubber, plastics and other common combustible materials.

• Mitigation

  • Use Water-Based Fire Extinguishers (e.g. water or water mist extinguishers) to cool the burning material.

  • Dry Chemical Extinguishers (ABC type) are also effective.

  • Avoid using water on electrical or grease fires, as it can spread the fire or cause electrical hazards.

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2. Class B Fires: Flammable Liquids and Gases:

• Materials Involved: Gasoline, oil, grease, propane, butane and other flammable liquids or gases.

• Mitigation

  • Use Foam Extinguishers or Carbon Dioxide (CO2) Extinguishers to smother the fire and cut off oxygen.

  • Dry Chemical Extinguishers (BC or ABC type) are also effective.

  • Avoid using water, as it can spread the flammable liquid and worsen the fire.

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3. Class C Fires: Electrical Fires:

• Materials Involved: Electrical equipment, wiring, appliances, and circuits.

• Mitigation

  • Use Carbon Dioxide (CO2) Extinguishers or Dry Chemical Extinguishers (BC or ABC type) to extinguish the fire without conducting electricity.

  • Once the power source is turned off, the fire can be treated as a Class A or B fire, depending on the materials involved.

  • Never use water, as it conducts electricity and can cause electrocution.

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4. Class D Fires: Combustible Metals:

• Materials Involved: Magnesium, titanium, sodium, potassium, and other reactive metals.

• Mitigation:

  • Use Dry Powder Extinguishers specifically designed for metal fires (e.g. Class D extinguishers).

  • Never use water, as it can react violently with combustible metals and worsen the fire.

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5. Class K Fires: Kitchen Fires (Cooking Oils and Fats):

• Materials Involved: Cooking oils, fats, and greases commonly found in commercial or residential kitchens.

• Mitigation

  • Use Wet Chemical Extinguishers designed for kitchen fires. These extinguishers cool the fire and create a foam layer to prevent re-ignition.

  • Avoid using water, as it can cause the hot oil to splatter and spread the fire.

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Fire Extinguisher Types and Their Uses:

1. Water Extinguishers: For Class A fires only.

2. Foam Extinguishers: For Class A and B fires.

3. Dry Chemical Extinguishers (ABC): For Class A, B, and C fires.

4. Carbon Dioxide (CO2) Extinguishers: For Class B and C fires.

5. Wet Chemical Extinguishers: For Class K fires.

6. Dry Powder Extinguishers: For Class D fires.

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General Fire Extinguisher using Tips:

• Always use the correct type of extinguisher for the fire.

• Follow the PASS technique when using a fire extinguisher:

  • Pull the pin.

  • Aim the nozzle at the base of the fire.

  • Squeeze the handle.

  • Sweep from side to side.

• Evacuate immediately if the fire is too large or uncontrollable.

• Regularly inspect and maintain fire extinguishers to ensure they are in working condition.