Flash point
Lowest temperature a substance can be heated in order for it to give off vapors which will burn when exposed to a flame or ignition source
Point of origin
Location where the fire started, find this by looking at burn patterns
Burn patterns
Noticeable patterns created by the fire as it burns, helps to locate where the fire started
Accelerants
Gasoline, paint thinner, alcohol, are some substances that accelerate a fire
Arson
Deliberate fire starting
Amount of oxygen that must be present to start a fire
16%
Ignition temperature
Low temperature you can start a fire with
Heat of combustion
Heat of reaction for the complete burning of a substance
Important factor of a fire
Rate of speed at which the oxidation reaction takes place
Flash over
Completely engulfed/dominated
Pyrolysis
Solid must be hot enough to decompose into gaseous product
Glowing combustion
Surface burning
Spontaneous combustion
RARE- natural heat- process in poorly ventilated containers or areas
3 Mechanics of heat transfer
Conduction, radiation, convection
Conduction
Movement of heat through solid object
Radiation
Transfer of heat energy by electromagnetic radiation
Convection
Transfer of heat energy by the movement of molecules with in a liquid or gas
Fire triangle
Shows the three elements needed to produce and sustain a fire: fuel, heat, oxygen
Fuel
Any combustible material in any state of matter
Examples of fuel
Clothing, furniture, curtains, flammable liquids
Oxygen
The air has 21% oxygen, fire requires an atmosphere of at least 16% oxygen
Heat
Is the energy necessary to increase the temperature of the fuel to a point where sufficient vapors are given off for ignition ?????point
Examples of heat
Stoves, heating appliances, fire places, damaged wiring
Fire clues
Point of origin, char patterns
Char Patterns
Caused by very hot fires that burn very quickly and move fast along its path. Lines between what is burned and what isn't may be found
V-Pattern
Fire burns up
A Narrow V shape
May indicate a hotter than normal fire, accelerant may have been used
A Wide V shape
May indicate a fire that was slow burning
U shaped
Makes it more difficult to find the point of origin; may also indicate that there was a "pool of origin
Heat shadows
Heavy furniture shields part of a wall; can help determine the origin point
Glass
Glass fragments, windows, and light bulbs can provide clues to a fire
Light bulbs
Melt toward the heat source
Shattered or cracked glass
Indicates how a fire burned
Clear glass with abnormal pattern of cracking
Could imply a very hot fire due to accelerant
Chimney effect
Fire ignites at a point, the superheated gases rise upward and form a fireball burning a hole in the cieling?
Color of smoke
Determines type of material burning
Color of flames
Indicates the temperature the fire was burning
Accidental system
- Electrical appliances
- Heating system
- Lighting
-Smoking
Arson clues
- Odors
- Locked windows, blocked doors
- Two or more points of origin?
- Inverted V-patterns
- Floors charred
- Trails that lead the fire from one place to another
Common motives for arson
- Crime concealment
- Insurance fraud
- Vandalism
Flash point
Lowest temperature a substance can be heated in order for it to give off vapors which will burn when exposed to a flame or ignition source
Point of origin
Location where the fire started, find this by looking at burn patterns
Burn patterns
Noticeable patterns created by the fire as it burns, helps to locate where the fire started
Accelerants
Gasoline, paint thinner, alcohol, are some substances that accelerate a fire
Arson
Deliberate fire starting
Amount of oxygen that must be present to start a fire
16%
Ignition temperature
Low temperature you can start a fire with
Heat of combustion
Heat of reaction for the complete burning of a substance
Important factor of a fire
Rate of speed at which the oxidation reaction takes place
Flash over
Completely engulfed/dominated
Pyrolysis
Solid must be hot enough to decompose into gaseous product
Glowing combustion
Surface burning
Spontaneous combustion
RARE- natural heat- process in poorly ventilated containers or areas
3 Mechanics of heat transfer
Conduction, radiation, convection
Conduction
Movement of heat through solid object
Radiation
Transfer of heat energy by electromagnetic radiation
Convection
Transfer of heat energy by the movement of molecules with in a liquid or gas
Fire triangle
Shows the three elements needed to produce and sustain a fire: fuel, heat, oxygen
Fuel
Any combustible material in any state of matter
Examples of fuel
Clothing, furniture, curtains, flammable liquids
Oxygen
The air has 21% oxygen, fire requires an atmosphere of at least 16% oxygen
Heat
Is the energy necessary to increase the temperature of the fuel to a point where sufficient vapors are given off for ignition ?????point
Examples of heat
Stoves, heating appliances, fire places, damaged wiring
Fire clues
Point of origin, char patterns
Char Patterns
Caused by very hot fires that burn very quickly and move fast along its path. Lines between what is burned and what isn't may be found
V-Pattern
Fire burns up
A Narrow V shape
May indicate a hotter than normal fire, accelerant may have been used
A Wide V shape
May indicate a fire that was slow burning
U shaped
Makes it more difficult to find the point of origin; may also indicate that there was a "pool of origin
Heat shadows
Heavy furniture shields part of a wall; can help determine the origin point
Glass
Glass fragments, windows, and light bulbs can provide clues to a fire
Light bulbs
Melt toward the heat source
Shattered or cracked glass
Indicates how a fire burned
Clear glass with abnormal pattern of cracking
Could imply a very hot fire due to accelerant
Chimney effect
Fire ignites at a point, the superheated gases rise upward and form a fireball burning a hole in the cieling?
Color of smoke
Determines type of material burning
Color of flames
Indicates the temperature the fire was burning
Accidental system
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Arson clues
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Common motives for arson
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