What is a fire extinguisher?

A fire extinguisher is a portable device that discharges an agent (such as foam, powder, CO₂, water) to extinguish or control small fires in emergency situations.

• A fire extinguisher contains a fire-suppressing agent under pressure. When activated, the agent is expelled through a nozzle to cover the fire.
• The goal is to remove one or more elements of the “fire triangle” (heat, fuel, oxygen) or to block the chain reaction of combustion. For example:
  • Water extinguishers cool the burning material.
  • Foam suppresses oxygen flow over fuel surfaces.
  • Dry chemical powder interrupts the chemical reaction.
  • CO₂ displaces oxygen and cools the fire.
• Fire extinguishers are classified by fire types (Class A = ordinary combustibles; B = flammable liquids; C = electrical; etc.). Choosing the correct type matters for safety.
• They are designed for small, contained fires. For larger fires one must evacuate and call fire services. Misuse of extinguisher can be dangerous or ineffective.