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FIRE INVESTIGATIONS
Fred Herrera, CFI
San Diego, CA
(760) 805-3842
www.fredherrera.com [email protected]
Copyright FHFI 2006
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
Copyright FHFI 2006
BASIC FIRE SCIENCE
Copyright FHFI 2006
Fire Triangle / Tetrahedron
Copyright FHFI 2006
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
Copyright FHFI 2006
Copyright FHFI 2006
HEAT TRANSFER
Copyright FHFI 2006
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.
Copyright FHFI 2006
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
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Combustible liquid
Kerosene, 100 F
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Flash point 100 F or above
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Vapors burn, not liquid
Fuel / air mixture
 LEL – Too lean
 UEL – Too rich
Explosive range – Bingo!
Copyright FHFI 2006
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
Copyright FHFI 2006
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
Copyright FHFI 2006
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)
Copyright FHFI 2006
Copyright FHFI 2006
Copyright FHFI 2006
Copyright FHFI 2006
Resistance heating of a plug
Copyright FHFI 2006
Copyright FHFI 2006
ARSON MOTIVES
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Crime concealment
Spite / revenge
Fraud / Profit
Excitement
Extremist
Vandalism
Pyromania
Copyright FHFI 2006
Copyright FHFI 2006
FIRE BOMBS
Copyright FHFI 2006
DRUG LABS
Copyright FHFI 2006
LAST CHANCE TO ASK!
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??
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Copyright FHFI 2006
THE END!
Copyright FHFI 2006
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