Forest Ecology and Fire Behavior - Colorado State University
Transcript of Forest Ecology and Fire Behavior - Colorado State University
Fire Behavior and Firefighter Safety & Tactics
The Fire Triangle
In order for a fire to occur, the three
things must be present:
• Enough oxygen to sustain
combustion.
• Enough heat to raise the material to
its ignition temperature.
• Some sort of fuel or combustible
material.
• All three elements must be present
at the same time to have a fire. Fire
will burn until one or more of the
elements is removed.
Suppressing & Extinguishing a fire is accomplished by:
• Fuel - Separate the fuel to prevent combustion or remove during fireline construction
• Oxygen - Suffocate the fire with dirt or water to rob the fire of oxygen
• Heat - Cool the fire by applying water, dirt, retardant or a combination
Heat Transfer• Radiation
• Convection
• Conduction
Radiation
• Radiant heat can dry surrounding fuels and sometimes ignite the surrounding fuels
ConvectionThe hot gases and embers which compose the smoke column
can dry and ignite other fuels.
ConductionHeat is conducted from one fuel particle to another
through direct contact.
Convection
Radiation
Conduction
What type of heat transfer do the arrows indicate?
Fire Environment Triangle
• Weather
• Topography
• Fuels
The Three Components of the
Wildland Fire Environment:
Primary Factors that Affect Rate of Spread
•Wind speed
• Steepness of slope
•Changes in fuel type
Fire intensity is primarily affected by:
• Fuel loading
• Compactness or arrangement of fuels
• Fuel moisture content
• The rate of spread
Three methods of attack used by wildland firefighters
•Direct Attack - Constructing a fireline right on the fire perimeter. Keeping one foot in the black and one foot in the unburned area.
•Indirect Attack - Constructing a fireline some distance from the fire perimeter. Should use a barrier ( natural or constructed) in fireline construction if available. Intervening strip is wide and fuels are burned out. Allows a choice of timing for burning out
• Parallel Attack - Constructing a fireline
parallel to but further from the fire
perimeter than in direct attack, due to
fire intensity. May shorten line by
cutting across unburned fingers.
Intervening strips of narrow fuels are
immediately burned out.
Burning Out:
Setting fire inside the control line
to consume fuel
between the
line and the
fire. “Black-line
concept”
Safety• 10 Fire Orders
• Look Outs
• Communications
• Escape Routes
• Safety Zones
• 18 Watch out situations
“Look Up, Look Up, Look Down, Look Around”
• Weather
• Fire Behavior
• Operations• Poor visibility
• Powerlines
• Faulty equipment
• Unfamiliar equipment
• Fatigue
• Smoke on highway
• Stress