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