Unit 2: Arson and Explosives

Griess test

The ________ detects the presence of nitrates and nitrates.

Canines

________ have more olfactory nerves than humans, so they are able to smell more better than us.

Primary explosives

________ detonate by ignition from some source such as flame, spark, impact, or other means that will produce heat of sufficient magnitude.

Techniques used to remove accelerants from debris = Heated headspace

Closed container - Samples headspace over residue

Techniques used to remove accelerants from debris = Purge and trap

Closed container - Uses charcoal strip or charcoal tube to trap accelerants - Uses vacuum or positive pressure with inert gas to force accelerant vapour through the charcoal trap

High Explosive Types

Initiating (or primary explosives) Non-initiating

Evidence of arson

Some telltale signs of arson are evidence of separate and unconnected fires, use of “streamers” to spread the fire from one area to another and evidence of severe burning found on the floor due to a flammable liquid.

### Components necessary for a fire?

Oxygen, heat and fuel

### Evidence of point of origin?

__**Probable origin**__= the lowest point is the most intense burning (fire moves upward) .Characteristics= V-pattern, spalling(blistering) of concrete, Beginning of the fire trail, Accelerant? …Accelerant flow to the lowest point and Gathering/piling of fuel materials.

### Preliminary screening for explosions? Dogs!

Preliminary field tests may be used for screening the debris on the explosion site. They include commercially available explosive vapor detectors and chemical color tests.

### Primary explosions

Primary explosives detonate by ignition from some source such as flame, spark, impact, or other means that will produce heat of sufficient magnitude.

### Secondary explosives

Secondary explosives require a detonator and, in some cases, a supplementary booster.

### High explosives

__**High Explosive Types:**__ Initiating (or primary explosives) Non-initiating. Secondary or base explosives) Includes Dynamite, TNT or PETN, and ANFOs.

### Low Explosives

**Low explosives Definition—** chemicals that oxidize rapidly, producing heat, light, and a pressure wave. will explode only when confined.