Fires and Suppression Methods


 What Exactly is a Fire?

These are the elements of a fire: Oxygen, heat, and a fueling agent.

You need to take one of those elements out of the equation to stop the fire.

Every fire can’t be put out with water.

Different types of fires need different types of extinguishers.

Suppression Methods


  • Displaces the oxygen molecules, so it cannot take part in the burning process
  • Water carries away heat from the fire in the form of steam, lowering the temperature


  • Smothers fires and prevents supply of oxygen
  • The water-based foam cools the burning material’s temperature

Dry Powder

  • Smothers the fire and separates fuel from oxygen
  • Covers surface area of fire and absorbs the heat
  • NOT the same as dry chemical!

Dry Chemical

  • Interrupts chemical process of fire
  • Mostly for Class B fires (oil, gas, liquids)


  • Colorless, odorless gas that sucks the oxygen out of an area
  • Extremely DANGEROUS should only be used in facility void of humans and animals, or not at all
  • Inexpensive


  • Disrupts the chemical process of fire
  • Example includes Halon and FM-200

Types of Fires


 Class A – Combustibles

  • Trash
  • Paper
  • Wood
  • Plastic

Suppression: Dry powder, water, foam


Class B – Liquids

  • Gasoline
  • Petrol
  • Paint

Suppression: Dry chemical, dry powder, foam, CO2, gas


Class C – Electrical

  • Electrical equipment
  • Wires
  • Sockets
  • Fuses

Suppression: Dry powder, CO2, gas


Class D – Metals

  • Magnesium
  • Titanium
  • Potassium
  • Zirconium

Suppression: Dry powder only, everything else may aid in spreading the fire


Class K – Kitchen Liquids

  • Cooking oils
  • Grease

Suppression: Potassium Acetate

  • Ahmed Khatib

    Cooking oil is part of Class K fire types and suppression agent is Potassium Acetate!

    Ahmed Khatib

    • studynotesandtheory

      Corrected, and thank you!