1. Types of Fire Extinguishers
Fire extinguishers are categorized in several ways:
By Mobility: Portable (Hand-held) and Wheeled.
By Propellant Source: Cartridge-operated, Stored-pressure, and Chemical-reaction.
By Fire Suppressant: Foam, Dry Powder, Halon, Carbon Dioxide (CO₂), Water, etc. Common types include Dry Powder (Class BC and ABC), Carbon Dioxide (CO₂), Halon (1211), and Foam extinguishers.
2. Fire Classes & Extinguisher Selection
Choose the correct extinguisher based on the fire class:
| Fire Class | Fuel Type | Recommended Extinguishers |
|---|---|---|
| Class A | Ordinary combustibles (wood, paper, cloth) | Water, Foam, ABC Dry Powder. |
| Class B | Flammable liquids (oil, petrol, paint) | ABC Dry Powder, CO₂. (Foam is suitable for oils but NOT for polar solvents like alcohol). |
| Class C | Flammable gases (propane, butane) | ABC Dry Powder, CO₂. (ABC Dry Powder is commonly deployed for A, B, & C fire risks). |
| Class D | Combustible metals (magnesium, sodium) | Typically require special agents (e.g., sand). Standard extinguishers are ineffective. |
| Class E | Energized electrical equipment | ABC Dry Powder, CO₂. (Never use water or foam on live equipment). |
General Guidance: ABC Dry Powder extinguishers are versatile for common risks. A standard recommendation is one 4kg unit per 75 square meters, often mounted in groups of four on a stand.
3. General Operating Instructions (P.A.S.S. Method)
PULL the safety pin to break the seal.
AIM the nozzle or hose at the base of the fire.
SQUEEZE the handle or lever to discharge the agent.
SWEEP from side to side across the fire until it is out.
Important: Carry the unit upright. For some types (e.g., older foam models), inversion and shaking may be necessary before operation. Always read the label first.
4. Specifics for Common Extinguisher Types
a) Dry Powder Extinguisher
Use For: Class A, B, C, and E fires (versatile).
How to Use: Follow P.A.S.S. from a safe distance (2-3 meters). The powder smothers and interrupts chemical combustion.
Key Notes: Store in a dry, accessible place. Check periodically for powder compaction (requires annual servicing).
b) Carbon Dioxide (CO₂) Extinguisher
Use For: Primarily Class B and E fires (ideal for electrical fires as it leaves no residue).
How to Use: Discharge using the P.A.S.S. method. Use the horn-shaped nozzle at the fire's base. CO₂ displaces oxygen and cools the fire.
Key Notes: Do not hold the horn (discharge horn) during use, as it becomes extremely cold and can cause frostbite. Regular inspection and refilling are crucial.
c) Foam (AFFF) Extinguisher
Use For: Class A and B fires (particularly effective on flammable liquids by forming a sealing layer).
How to Use: Invert or follow manufacturer's instructions to activate, then aim and sweep. Forms a blanket that smothers flames and prevents re-ignition.
Key Notes: Protect from freezing and direct sunlight. Do not use on electrical or Class C fires. After use, place the unit on its side with the nozzle down.
5. Critical Safety Reminders
Early Intervention: Extinguishers are for containing small, initial fires. Your safety comes first—evacuate if the fire spreads quickly.
Sound the Alarm: Always activate the fire alarm and call emergency services first, before attempting to use an extinguisher. Do not rely solely on the extinguisher.
Know Your Limits: Operate only if you are trained, the fire is small, and you have a clear escape route. Never let the fire block your exit.
Maintenance: Ensure regular professional inspection and servicing as required by local regulations.
Disclaimer: This guide provides general information. Always prioritize manufacturer instructions, workplace safety protocols, and formal fire safety training.