Understanding the different types of fires, selecting the appropriate fire extinguisher, and knowing how to use it properly are essential skills for workplace safety. Fires can escalate quickly, so immediate and effective action is crucial for protecting both people and property.

Types of Fires

Fires are categorized by the type of fuel they use, as each type of fire requires a specific approach to extinguish it. Knowing the fire classes helps in choosing the correct fire extinguisher.

  1. Class A – Ordinary Combustibles:
    • Description: Fires involving common combustible materials, such as wood, paper, cloth, rubber, and plastics.
    • Extinguishing Method: Use water or foam extinguishers to cool and smother the fire, removing the heat.
  2. Class B – Flammable Liquids and Gases:
    • Description: Fires fueled by flammable liquids like gasoline, oil, solvents, and grease or gases like propane and butane.
    • Extinguishing Method: Use foam, CO₂, or dry chemical extinguishers to cut off the oxygen or interrupt the chemical reaction.
  3. Class C – Electrical Fires:
    • Description: Fires involving energized electrical equipment such as appliances, wiring, circuit breakers, and machinery.
    • Extinguishing Method: Use non-conductive extinguishing agents like CO₂ or dry chemicals to avoid the risk of electric shock. Never use water on electrical fires.
  4. Class D – Metal Fires:
    • Description: Fires involving combustible metals like magnesium, titanium, and sodium, often found in industrial settings.
    • Extinguishing Method: Use a dry powder extinguisher specifically designed for metal fires to smother the flames and prevent further reactions.
  5. Class K – Cooking Oils and Greases:
    • Description: Fires involving cooking oils or fats, commonly found in commercial kitchens.
    • Extinguishing Method: Use a Class K extinguisher that contains a wet chemical agent to cool the fire and prevent re-ignition.

Fire Extinguisher Types

Different types of fire extinguishers are designed to handle specific classes of fire. Understanding the various extinguishers helps ensure the correct one is used in an emergency.

  1. Water Extinguishers (Class A):
    • Usage: Effective on Class A fires involving wood, paper, and other ordinary combustibles.
    • Not Suitable For: Class B, C, D, or K fires, as water can spread flammable liquids and conduct electricity.
  2. Foam Extinguishers (Class A and B):
    • Usage: Suitable for Class A fires and Class B fires involving flammable liquids. The foam forms a barrier over the fuel source, cutting off the oxygen.
    • Not Suitable For: Class C fires (electrical) due to the water content in the foam, which conducts electricity.
  3. Carbon Dioxide (CO₂) Extinguishers (Class B and C):
    • Usage: Effective for Class B and C fires. The CO₂ gas displaces oxygen, suffocating the fire, and does not leave a residue.
    • Not Suitable For: Class A fires, as CO₂ does not cool the fire effectively and may not prevent re-ignition.
  4. Dry Chemical Extinguishers (Multipurpose for Class A, B, and C):
    • Usage: The most versatile type, dry chemical extinguishers are effective on Class A, B, and C fires. The chemical disrupts the chemical reaction of the fire.
    • Types:
      • ABC Dry Chemical: Suitable for Class A, B, and C fires.
      • BC Dry Chemical: Suitable for Class B and C fires but not effective on Class A fires.
  5. Dry Powder Extinguishers (Class D):
    • Usage: Specifically designed for Class D fires involving combustible metals.
    • Not Suitable For: Class A, B, or C fires, as the dry powder can spread the flames on flammable liquids and may not control other types of fire.
  6. Wet Chemical Extinguishers (Class K):
    • Usage: Ideal for Class K fires involving cooking oils and fats. The wet chemical cools and creates a soapy barrier to prevent re-ignition.
    • Not Suitable For: Class A, B, C, or D fires due to its specialized application.

How to Use a Fire Extinguisher: The PASS Method

Using a fire extinguisher correctly is vital for putting out a fire quickly and safely. The PASS method provides an easy-to-remember sequence:

  1. P – Pull the pin:
    • Remove the safety pin from the handle to unlock the extinguisher, allowing you to discharge it.
  2. A – Aim the nozzle:
    • Aim the nozzle or hose at the base of the fire, where the fuel source is, rather than at the flames.
  3. S – Squeeze the handle:
    • Squeeze the handle slowly to release the extinguishing agent. Be ready for a brief delay as the contents begin to discharge.
  4. S – Sweep from side to side:
    • Sweep the nozzle back and forth across the base of the fire, moving from side to side until the fire is extinguished. If the fire does not go out immediately, or if it begins to grow, evacuate and call for help.

Steps for Putting Out a Fire

  1. Assess the Situation:
    • Determine if the fire is small and manageable or if it requires evacuation and emergency response. Never try to put out a large fire on your own.
  2. Identify the Fuel Source:
    • Quickly identify the type of fuel (e.g., paper, liquid, electrical) to choose the correct extinguisher.
  3. Use the Correct Extinguisher:
    • Select the appropriate extinguisher based on the fire class and follow the PASS method.
  4. Maintain a Safe Distance:
    • Stand a safe distance from the fire while using the extinguisher. Stay low if smoke is present, as smoke inhalation is a common cause of injury.
  5. Ensure the Fire is Out:
    • Monitor the fire area after extinguishing it to ensure it does not reignite. If it does, repeat the process or evacuate if the fire grows uncontrollably.
  6. Call Emergency Services if Needed:
    • Even if you put out the fire, call emergency services if there was a substantial fire to ensure it’s fully extinguished and the area is safe.
  7. Evacuate If Necessary:
    • If the fire becomes too large or uncontrollable, activate the nearest fire alarm, evacuate immediately, and follow your workplace’s fire evacuation plan.

Fire Safety Tips

  • Know Your Extinguishers: Familiarize yourself with the locations and types of fire extinguishers in your workplace.
  • Regular Training: Participate in regular fire safety and extinguisher training to remain proficient in using fire extinguishers.
  • Check Extinguishers Regularly: Ensure that all fire extinguishers are inspected regularly for proper pressure and functionality.
  • Stay Calm: Fire emergencies require a clear mind. Follow the PASS method and be ready to evacuate if needed.

Summary

Understanding the types of fires, selecting the correct fire extinguisher, and using it effectively with the PASS method can make all the difference in an emergency. Regular fire safety training, knowing when to act, and calling for help when needed ensure that workers are prepared to handle small fires safely while protecting themselves and their colleagues.

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