NATS 1575 Lecture 25: Chapter 13: Forensic Aspect of Fire Investigation
17 Apr 2018
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Document Summary
Arson investigations often present complex and difficult circumstances to investigate due to the fact that the perpetrator has thoroughly planned the act, is not present during the act, and the destruction is so extensive. The criminalist"s function is rather limited to detecting and identifying relevant chemical materials collected at the scene and reconstructing and identifying igniter mechanisms. Chemically, fire is a type of oxidation, which is the combination of oxygen with other substances to produce new substances. To start fire, the minimum temperature needed to spontaneously ignite fuel, known as ignition temperature, must be reached. The heat evolved when a substance burns is known as heat of combustion. An additional factor, besides the liberation of energy, needed to explain fire is the rate or speed at which the oxidation reaction takes place. A fuel will achieve a reaction rate with oxygen sufficient to produce a flame only when it is in the gaseous state.
