The 3 Components of the Fire Triangle
Fire, it's one of the greatest tools used to benefit human development but only when we control it. Without control, fire is one of the most destructive forces that humankind has ever encountered.
To better understand what methods we may use to limit such destructive power, we must first separate fire into its 3 main components:
This graphic below clearly shows the links between these components.
Once these 3 components are present - there is only one more requirement - something to start the fire - this is an ignition source. Examples of ignition sources include:
- Fallen power lines
- Burning cigarette-butts
- Sparks from machinery
- Vehicles with hot exhaust pipes
Note in the graphic, that all of the components form a triangle which encloses the fire graphic. For fire to continue burning, each component must be present. If we take 1 or 2 elements away then the fire will quickly stop burning.
This is the key to controlling fire.
Once fire takes hold, it requires continuing and increasing amounts of each of these elements to grow larger and therefore more dangerous. Thus, the fire needs more:
- Air -- this allows burning or combustion to continue,
- Fuel -- such as dry grass, fodder, logs and trees, and
- Heat -- hotter & larger fires in turn, burn more fuel and generate winds that feed more air into the fire.
This is why bush fires on days with high temperatures, low humidity and hot, dry winds are so dangerous. It begins a chain reaction process, that is:
The only way to control fire is to remove any one of the components. For example, when:
- Air is removed - the fire suffocates - the flames immediately die down and the fire goes out.
- Fuel is removed - there is nothing to burn - the fire starves and soon reduces to embers.
- Heat is removed - this cools the fire - slows combustion and prevents the fire from spreading.
The most common method used to control or suppress bush fires is to remove heat. Firefighters use water to extinguish fires because it;
- Lowers the very high temperatures generated by the fire
- Lowers the fire intensity - un-burned fuel loads do not reach their ignition temperatures
- Slows the burn-rate - the fire becomes more controllable
Most Fire Brigades use special chemicals to increase the extinguishing properties of the water used to put out the fire. This solution is then sprayed onto the fire as a foam that 'sticks' to the burning fuel. It has a suffocating effect and also reduces the heat, much better than water alone.