Forensic Fire

Question 1

What is a fire:

Answer 1

The rapid oxidation of a fuel with the evolution of heat and light.

Question 2

The 3 requirements needed to start and sustain a fire or combustion

Answer 2

1. a fuel must be present
2. oxygen must be available in sufficient quantity to combine with the fuel
3. heat (IGNITION) must be applied to initiate the combustion, and sufficient heat must be generated to sustain the reaction

Question 3

Combustion of materials

Answer 3

Combustion of materials can result in flames or in can just produce heat and light (glowing combustion)

Question 4

What is an accelerant:

Answer 4

Any fuel that is used to start, spread, or increase the intensity of a fire

Question 5

What is meant by ignition temperature:

Answer 5

The minimum temperature an ignitable substance must reach in order to ignite.
eg. gasoline has an ignition temperature of 495 deg F.

Question 6

What is meant by “flash point”:

Answer 6

The lowest temperature at which an ignitable liquid produces sufficient vapors to support a momentary flame.

Question 7

Spontaneous Combustion - Requirements: 3 points

Answer 7

1. a process that slowly releases heat e.g. oxidation of oils, microbe metabolism
2. insulation of the substrate so that heat is retained and can accumulate
3. availability of air for combustion

Question 8

Roles of a forensic chemist in fire investigations: 4 points

Answer 8

1. Identify ignitable liquids, such as gasoline or fuel oil, in debris samples.
2. Identify liquids found at fire scenes.
3. Identify materials (i.e. types of plastic) in samples of burned debris.
4. Measure flash points of liquids

Question 9

PATTERN ANALISIS:

Answer 9

Cannot identify a specific brand of an accelerant like gasoline or varsol.