Fire Behavior
What is smoke?
The visible accumulation of air born gases, particulates, and aerosols due to incomplete combustion or pyrolysis.
Define combustion
Chemical process of oxidation that occurs rapidly to produce heat and light
What temp range does flashover occur?
1000 - 1200
What are the three types of heat transfer?
Conduction, convection, radiation
What reaction gives off heat?
Exothermic reaction
What is pyrolosis of wood temperature?
300 - 400 degrees
Define heat of combustion
total amount of thermal energy that could be generated by the combustion reaction if a fuel were completely burned
What gas has the highest flammable range?
Carbon monoxide
What do laminar levels of thermal layers indicate?
Stable conditions
convection, conduction, and radiation
Define temperature
Measurement of how fast the particles in a substance are moving.
Define HRR? (heat release rate)
The energy released per unit of time. Measured KW or HP.
If a gas is said to be too rich it means?
The gas is above the flammable range
What are the elements in the fire tetrahedron?
Fuel, heat, oxygen, chemical chain reaction
What is found in the early stages of fire?
What are found in the later stages of fire?
Fuel limited fires
vent limited fires
Define heat
transfer of energy from one substance to another as a result of temperature difference
What are the phases of fire in order?
Ignition, Growth, Fully Developed, Decay
What are examples of extreme fire behavior?
flashover, backdraft, smoke explosion
What is the first priority for the engine company?
Search and control of the fire
The primary effort to an attic fire is to control?
Define fire dynamics
Detailed study of how chemistry, fire science and the engineering disciplines of fluid mechanics and heat transfer interact to influence fire behavior
Pyrolysis of materials, intense heat forcing crews down, sudden lowering of neutral plane (dense smoke), increased turbulence of neutral plane (air flow), rollover present, ventilated fire, lowering neutral plane, increasing heat
How do you prevent flashover?
Cool environment, coordinate ventilation, back out and re evaluate
What method of heat transfer has currents follow the path of least resistance spreading smoke, superheated gases and flammable vapor?
Convection
When reading smoke, look for:
Volume, Velocity, Color, *density