Firefighting techniques depend on the fire class (A, B, C, D, E/K, F) and the environment. Here are the primary methods used to extinguish fires:
1. Cooling (Temperature Reduction)
Principle: Remove heat from the fire triangle.
Methods:
✔ Water – Best for Class A fires (wood, paper, textiles).
✔ Water mist – Cools and displaces oxygen (good for electrical fires if de-energized).
✔ CO₂ (Carbon Dioxide) – Cools flames while smothering (used for Class B & E fires).
Limitations:
Not for grease (Class F) or metal (Class D) fires.
Water conducts electricity (dangerous for live electrical fires).
2. Smothering (Oxygen Removal)
Principle: Cut off the fire’s oxygen supply.
Methods:
✔ Fire Blanket – For small Class F (grease) & clothing fires.
✔ Foam (AFFF) – Forms a barrier on flammable liquids (Class B).
✔ CO₂ & Dry Powder – Displaces oxygen in electrical/chemical fires.
✔ Sand/Dirt – Used for small Class D (metal) fires.
Limitations:
Less effective on deep-seated fires (e.g. large wood fires).
3. Starvation (Fuel Removal)
Principle: Eliminate the fuel source.
Methods:
✔ Shut off gas supply (for gas fires).
✔ Remove flammable materials (wood, paper, liquids).
✔ Firebreaks (used in wildfires to stop spread).
Limitations:
Not always practical (e.g. building fires where fuel is structural).
4. Chemical Inhibition (Breaking the Chain Reaction)
Principle: Interrupts the chemical reaction of fire.
Methods:
✔ Dry Chemical Powder (ABC Powder) – Works on Class A, B, C & E fires.
✔ Clean Agents (FM-200, Novec 1230) – Used in data centers for electrical fires.
Best for:
Industrial & electrical fires.
5. Specialized Firefighting Methods
✔ Class D (Metal) Fires – Use dry powder (e.g., sodium chloride).
✔ Class F (Cooking Oil) Fires – Wet chemical extinguishers or fire blankets.
✔ Wildfires – Firebreaks, aerial water drops, retardants.
✔ Electrical Fires – CO₂ or dry powder (after de-energizing).
Fire Extinguisher Types & Uses
| Type | Works On | Not For |
|---|---|---|
| Water | Class A (wood, paper) | Electrical, grease |
| Foam | Class A & B | Electrical, metals |
| CO₂ | Class B & E | Class A (no cooling) |
| Dry Powder | Class A, B, C, E | Class D (some types) |
| Wet Chemical | Class F (grease) | Class B, E |
Firefighting Techniques in Different Scenarios
1. Kitchen Fires
✔ Grease fire? Cover with lid/fire blanket (NEVER water!).
✔ Oven fire? Keep door closed, turn off heat.
2. Electrical Fires
✔ Cut power first Use CO₂ or dry powder.
✔ Never use water (risk of electrocution).
3. Industrial Fires
✔ Gas leaks? Evacuate, let professionals handle it.
✔ Chemical spills? Use appropriate suppressant (foam/dry powder).
4. Wildfires
✔ Defensible space (remove dry vegetation).
✔ Fire retardants (dropped by planes).
Key Takeaways
✔ Stop the fire early (small fires grow fast).
✔ Use the right method (wrong extinguisher can worsen fire).
✔ Evacuate if unsure Safety first!
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