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FIRE INVESTIGATIONS
Fred Herrera, CFI
San Diego, CA
(760) 805-3842
www.fredherrera.com [email protected]
NATIONWIDE STATS
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2 million fires reported
9.4 billion dollars damage
5,000 fatalities
100 firefighter fatalities
25,500 injuries
#1 cause of fires: cooking
#1 cause of fire deaths: smoking
BASIC FIRE SCIENCE
Fire Triangle / Tetrahedron
COMBUSTION
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Heat
Fuel
Oxygen
Uninhibited chemical chain reaction
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FOR FIRE SCENARIO
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HEAT, FUEL, OXYGEN & EVENT
HEAT TRANSFER
IGNITION OF SOLIDS
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Material must be pyrolyzed, or chemically
decomposed, by the application of heat.
Density and surface area affect ignitability.
Heat source must have ability to transfer
sufficient heat, for sufficient duration, to
fuel source.
IGNITION OF LIQUIDS
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Flammable / Combustible
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Flash point below 100 F
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Flammable liquid
Gasoline, -44 F
Flash point 100 F or above
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Combustible liquid
Kerosene, 100 F
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Vapors burn, not liquid
Fuel / air mixture
 LEL – Too lean
 UEL – Too rich
Explosive range – Bingo!
FIRE ORIGIN DETERMINATION
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EXTERIOR EXAMINATION
INTERIOR EXAMINATION
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Least damage to worst
Identify area of origin
RECONSTRUCTION
FIRE-SPREAD SCENARIO
FIRE CAUSE DETERMINATION
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Accidental
 Appliance failure
Natural
 Lightning
Incendiary
 Fraud
Undetermined
 Black holes
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Examine indicators
Identify possible causes
Identify heat, fuel &
event
Rule out other causes
Determine cause
 Render opinion
SYSTEMATIC APPROACH
SCIENTIFIC METHOD
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Recognize the need
Define the problem
Collect data
Analyze the data
Develop a hypothesis
Test the hypothesis
Select final hypothesis (determine cause)
Resistance heating of a plug
ARSON MOTIVES
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Crime concealment
Spite / revenge
Fraud / Profit
Excitement
Extremist
Vandalism
Pyromania
FIRE BOMBS
DRUG LABS
LAST CHANCE TO ASK!
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??
??
??
THE END!