Fire, Arson Etc. Flashcards
The air we breathe is about __% oxygen
21
Fire needs and atmosphere with about __% oxygen
16
A liquid burns when the when the temperature is high enough to vaporize it. Known as..
flash point
In order for there to be a fire, solid must be hot enough to decompose into gaseous products. Know as…
pyrolysis
In order to initiate and sustain combustion, three things are needed
1) Fuel
2) Oxygen
3) Heat
The three mechanisms of heat transfer are…
conduction, radiation, convection
The three major signs of arson are
1) Streamers
2) Separate unconnected fires
3) Burning on the floor in stead of ceiling (Due to gas on the floor)
Traces of flammable liquid residues may be located with a _____ ______
Vapor Detector (sniffer)
It is important that a sampling of similar but uncontaminated _______ ______ be collected.
control specimens
In the laboratory, the ____ _____________ is the most sensitive and reliable instrument for detecting and characterizing flammable residues.
gas chromatograph
Fire is produced when a
Substance undergoes rapid oxidation involving heat and light.
Fire Triangle
Shows the three elements needed to produce and sustain a fire.
Flash Point
The lowest temperature to which a substance must be heated in order for the substance to give off vapors which will burn when exposed to a flame or ignition source.
Point of Origin
The location where the fire started.
Burn patterns
Noticeable patterns created by the fire as it burns.
Accelerants
Substances, such as gasoline, paint thinner, and alcohol, that accelerate the burning process.
Arson
A fire started deliberately.
Char Patterns
Created by very hot fires that burn very quickly and move fast along its path, so that there can be sharp lines between what is burned and what isn’t.
V-Patterns
Fire burns up, in a V-shaped pattern, so a fire that starts at an outlet against a wall leaves a char pattern that points to the origin.
Heat Shadows
Occur when heavy furniture shields part of a wall; can help determine the origin point.
Chimney Effect
Since fire burns upwards, there can be a “chimney effect” where the fire ignites at a point, the superheated gases rise upward and form a fireball, which continues straight up to burn a hole in the ceiling. If the roof is not entirely burnt, and the fire investigator finds such a hole, the origin of the fire could be directly underneath.
Color of smoke can help determine…
What type material was burning
Color of flames indicates…
at what temperature the fire was burning.
Explosives are…
substances that undergo a rapid oxidation reaction with the production of large quantities of gases.
How are explosives classified
The speed at which explosives decompose
The most widely used explosives in the ____-_______ group are black powder and smokeless powder.
Low-explosive
The most widely used explosives in the low-explosive group are…
black powder and smokeless powder.
Black powder is a mixture of…
potassium or sodium nitrate, charcoal, and sulfur.
Smokeless powder consists of…
nitrated cotton (nitrocellulose) or nitroglycerin and nitrocellulose.
True or False: Secondary explosives must be detonated by a primary explosive
True
__________________ is a homemade explosive that has been used by terrorist organizations.
Triacetone triperoxide (TATP)
TATP can be made by combining _____ and ______in the presence of an acid.
acetone and peroxide
What does TATP stand for?
Triacetone triperoxide
One approach for screening objects for the presence of explosive residues in the field or laboratory is the _____ ________ _______
ion mobility spectrometer (IMS)
Debris and articles collected from _____ ______ are to be packaged in separate air-tight containers.
different areas
Debris and articles collected from different areas are to be packaged in…
separate air-tight containers
