A. Characteristics
1. An explosive is a chemically unstable material.

2. Initiation produces an explosion or detonation.

3. Changes in pressure accompany this transformation.

4. Contain enough oxidizer to maintain extremely rapid combustion.

B. Requirements to be classified as an explosive material
In order to be classified as an explosive material the product must meet specific criteria, including

1. Fuel

Solid or Liquid Fuel.
2. Oxidizer
Oxygen balance is the percentage of fuel in relationship to the oxidizer in an explosive and is important so that the proper reaction occurs.
C. Classification of Explosive Materials
1. Low Explosives

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a. An explosive mixture which under any condition cannot support a detonation wave

b. Material is a mixture

c. Initiated by heat.

d. Confinement required for explosion

e. VOE below 3000 ft/sec

Examples: Black powder, smokeless powder
2. High Explosives

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a. Material undergoes detonation without confinement.

b. Material is a compound

c. Initiated by shock or heat

d. No confinement required

e. Supersonic reaction in the product.

f. High brisance, although the brisance will vary between each of the explosives as VOD and power changes.

g. VOD above 3300 ft/sec

Examples: Dynamite, ANFO, PETN
D. Explosives Performance
1. Low Order Detonation
Incomplete burning of the explosive material or initiation of the material at less than maximum velocity. In some instances, the detonation wave will not continue to propagate through the explosive material and there will be unexploded explosives remaining.
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2. High Order Detonation

Complete burning of the explosive material or initiation of the material at maximum velocity.
3. Sample causes of Low Order Detonation
Old or deteriorated explosives

Poor contact

Insufficient fuzing system

Premature failure of the containing device.

E. Sensitivity of Explosives
The amount of external force or stimuli required to initiate the chemical reaction in an energetic material. The term sensitivity is often used loosely to indicate the absolute or relative ease with which an explosive can be induced to react chemically. It should be noted that the stimulus to which the explosive is exposed must be included in any reference to the sensitivity, whether shock, low velocity impact, friction, electrostatic discharge, or other source of energy.

The shock initiation sensitivity of an explosive is the ease with which it can be induced to detonate.

Initiation of detonation by transition from deflagration to detonation (DDT) is another important consideration.

1. Primary Explosives

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a. Those explosives which require a very small quantity of energy to be initiated

b. Extremely sensitive to heat, shock and friction

c. Less power than secondary explosives

d. Classified as High Explosives

e. Used in detonators and initiation systems

Examples: Lead Azide, Mercury Fulminate
2. Secondary Explosives

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a. Those explosives which are relatively, in comparison to primary explosives, insensitive to shock, friction or heat.

b. Cap or booster sensitive

c. Less sensitive than primary explosives

d. Classified as High Explosives

e. More powerful than primary explosives

Examples: Dynamite, ANFO, RDX, PETN
F. Explosive or Firing Trains (Initiation Sequence)

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An explosive or firing train is a sequence of events which begin with relatively low levels of energy that causes a chain reaction to initiate the final explosive material or main charge. Can be a low or high explosives train.

1. Low Explosive Trains

Example: Small arms ammunition.
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Primer and a propellant charge.
Flame/Heat ignites the propellant charge

Gases produced

Drives the bullet through the bore of the weapon

2. High Explosives Trains:
a. Two-Step
Detonator and Dynamite
Step 1 - Initiation of the detonator

Step 2 - The exploding detonator causes the dynamite to be initiated.

b. Three-Step
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Detonator, Booster and ANFO
Step 1 Initiation of the detonator

Step 2 - The exploding detonator causes the booster to be initiated.

Step 3 - The exploding booster causes the ANFO to be initiated.

G. Additional Characteristics of Explosives
Explosive force is released at 90 degree angles from the surface of an explosive. Consequently, if the system is cut or shaped to form 90 degree surfaces along a predetermined plane the explosive forces can be focused directionally, and will produce a greater effect than the same explosive employed as a mass. Therefore the following shapes and configurations have been utilized to increased the effectiveness of high explosives.

1. Conical (Monroe)

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A cone having a metal, glass or plastic liner covered by an explosive. The angle of the explosive and the stand-off distance direct a jet towards the object.
2. Linear

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This charge has a liner like a conical or cone, explosive charge is covered by a liner, but in the shape of a flat plane.
3. Platter (Misznay-Schardin)
A solid piece of material, usually metal, with a quantity of explosives placed on only one side or plane.