FIRE INVESTIGATION

CHEMISTRY OF FIRE

• Fire is a type of oxidation
• Ignition temperature: minimum temperature needed to start a fire
• Heat combustion: Heat evolved when a substance burns
• Rate or speed is how fast the oxidation reaction takes place

CHEMISTRY OF FIRE CONT.

• Flash point occurs when temperature is high enough to vaporize
• Cigarette burning is known as glowing combustion
• Spontaneous combustion is due to natural causes

REQUIREMENTS FOR COMBUSTION

• Fuel must be present
• Oxygen must be available
• Heat must be applied

FIRE SCENE

• Arson investigator starts by examining fire for arson signs
• Start of this begins with fires origin
• Warrant needed to search for investigation

SIGNS OF ARSON

• Unconnected fires
• Use of streamers to spread fire
• Evidence of severe burning due to flammable liquid

THE COLLECTION AND PRESERVATION

• Must be stored in air tight containers
• Vapor detectors traces flammable liquids
• Ignitors are also collected including matches

ANALYSIS OF FLAMMABLE RESIDUES

• Oxygen must be present
• Combining with fuel
• Creating light and heat known as flames
• Cause a reaction rate with oxygen amount and fuel amount

FLAMMABLE RESIDUES

• Gas chromatography is used to separate residues and hydrocarbon components
• Recovered liquids and tested to identify the accelerant used