The Science of Fire and the Fire Triangle

The Science of Firefighting

  • Firefighting is defined as a science rather than just a physical activity.
  • Understanding the chemical and physical properties of fire is a prerequisite for entering the field of career firefighting.

The Fire Triangle

  • To sustain what is described as a "decent fire," three specific components must be present simultaneously. This concept is visualized as a triangle.
  • If any one of these three components is removed or missing, the fire will die out.
  • Component 1: Oxygen
    • Often referred to as "air."
    • Oxygen is necessary for the chemical reaction of combustion to occur.
  • Component 2: Ignition
    • This is the heat source or the trigger that starts the fire.
    • It is the initial energy required to begin the combustion process.
  • Component 3: Fuel (The Source)
    • This is the material that keeps the fire going.
    • The transcript identifies several specific examples of fuel sources:
      • Gas
      • Oil
      • Wood

Management of Large-Scale Fires

  • In nature, large fires are managed by manipulating the components of the fire triangle.
  • Controlled Burns: This involves intentionally burning a patch of land ahead of a major approaching fire.
    • Process: Firefighters start fires in a controlled manner to clear vegetation and material in the path of a larger, uncontained fire.
    • Scientific Logic: By pre-burning the land, the "fuel source" component of the triangle is removed.
    • Outcome: When the large fire reaches the area of the controlled burn, it has no fuel left to consume, which prevents it from progressing further.

Questions & Discussion

  • Speaker: "There's three parts to a fire that you three parts of a triangle that you need to really have a decent fire. What are the three parts of that triangle? I think I know it, but I know. Take a guess. What do you need to have a fire?"
  • Audience: "Air. Oxygen."
  • Speaker: "So air. Right? Okay. What else do you need to have a fire? Right?"
  • Audience: "Some type of ignition."
  • Speaker: "What's the last thing you need to have a fire?"
  • Audience: "A plane. A source."
  • Speaker: "A source. Source. A source. It could be gas. It could be oil. It could be, you know, wood, whatever the source is. Right?"
  • Speaker: "You ever wonder why you ever see, like, you know, fire in nature, like a big fire? They start creating fires ahead of a big fire… Why are they doing what's called a controlled burn?"
  • Audience: "So it can't progress."
  • Speaker: "So it can't progress. They're they're canceling what out of that triangle? Not oxygen."
  • Audience: "The fuel."
  • Speaker: "The fuel source. Right? So if I burn all this high"