Fire Extinguishment Methods & Extinguisher Types

Fire Extinguishment Methods

Cooling: Reducing Fuel Temperature

This method reduces the temperature of the fuel, causing the fire to extinguish as no vapors can escape to sustain combustion. Water is the most effective agent for this purpose.

Suffocation: Cutting Off Oxygen

This method prevents vapors released from the fuel at a certain temperature from contacting oxygen in the air, thereby cutting off the oxygen supply to the fire.

Inhibition: Chemical Fire Suppression

This method prevents the transmission of heat from one fuel particle to another by interposing catalysts. It involves applying chemicals that alter the chemistry of the combustion reaction. Examples include PQS (Dry Chemical) and Halon fire extinguishers.

Dilution: Fuel Removal

This method involves the elimination of the fuel source or physically separating the flame from the burning substance.

Types of Fire Extinguishers

Pressurized Water Extinguisher

These extinguishers can be operated intermittently, are rechargeable, and offer relatively powerful and long discharge times. They typically comprise a single chamber containing the agent and expulsion gas, a cap or head with a siphon tube, a combined transport and drive lever, a dump valve, a manometer, a contrast valve, and a pressurization valve. The discharge hose and nozzle are also key components.

Pump Water Extinguisher

• Cylindrical Model

  Features carrying handles attached to the container or built-in with the pump. Water is discharged through a manually operated vertical piston pump. Hose models are available in cylindrical containers made of copper, steel, and plastic.

  • Disadvantages:
  • Pumping must stop to move the extinguisher.
  • Discharge strength, reach, and duration depend on the operator.

• Tank-Type Pumping Backpack

  Another common design for pump water extinguishers.

Soda-Acid Extinguisher

This type contains a load of baking soda dissolved in water. Within a separate receptacle, there is a small bottle of sulfuric acid. When the extinguisher is inverted for use, the contents of the acid bottle pour into the bicarbonate solution, producing carbon dioxide. This gas creates the necessary pressure for the extinguisher to expel its contents.

Foam Fire Extinguisher

This extinguisher contains an aqueous solution of sodium bicarbonate with an added foam stabilizer. In a separate receptacle, there is an aluminum sulfate solution. When the extinguisher is activated (often by inversion), these solutions mix to form carbon dioxide. The ejected foam consists of carbon dioxide bubbles, which smother the fire.