Military Explosives
Part One


Definitions

Military Demolition:
Military demolition is the destruction by fire, water, explosive, mechanical,
or other means of area structures, facilities, or materials to accomplish a
military objective.  Demolitions are explosives used for such purposes.
Demolitions have offensive and defensive uses.  Examples are the removal of
enemy barriers to facilitate the advance and the construction of friendly
barriers to delay or restrict enemy movement.

Explosives:
Explosives are substances that, through chemical reaction, violently change to
a gaseous form.  In doing so, they release pressure and heat equally in all
directions.  They are classified as low or high according to the detonating
velocity or speed (in meters or feet per second) at which this change takes
place and other characteristics such as their shattering effect.

Low Explosives:
Low explosives change from a solid to a gaseous state slowly aver a sustained
period (up to 400 meters or 1,300 feet per second).  This characteristic makes
low explosives ideal when a pushing or shoving effect is required.  Examples of
low explosives are smokeless and black powders.

High Explosives:
High explosives change to a gaseous state almost instantaneously at 1,000
meters per second (3,280 feet per second) to 8,500 meters per second
(27,888 feet per second), producing a shattering effect on the target.
Use high explosives when a shattering effect, or brisance, is required.

Relative Effectives (RE) Factor:
Explosives vary in detonating rate or velocity (meters or feet per second), as
well as other characteristics, such as density and energy production.
These characteristics determine their effectiveness for cutting, breaching, or
cratering charges.  Most military demolitions involve cutting or breaching.
The amount of explosive used is adjusted by a relative effectiveness (RE)
factor, which is based upon the shattering effect of the explosive in relation
to that of trinitrotoluene (TNT).  The shattering effect of a high explosive is
related to its detonating velocity.  For example, TNT with a detonating
velocity of 6,900 meters per second has a relative effectiveness factor of
1.00, while Composition C4 with a detonating velocity of 8,040 meters per
second has a relative effectiveness factor of 1.34.

Cratering Effect:
The cratering effect of high explosives depends upon their total energy
content, which determines the amount of energy available to throw the broken
material from the crater.  Because a shattering effect is not required to form
a crater, low-velocity explosives are generally more effective for cratering
purposes.  Therefore, the relative effectiveness factor is not considered in
determining the effect of a cratering charge.  Blasting road craters or ditches
normally requires large amounts of explosives.  Because it is effective and
inexpensive, an ammonium nitrate-based cratering charge is used as a standard
cratering charge.


Characteristics

To be suitable for use in military operations, explosives must have certain
properties.  Military explosives must -- Be inexpensive to manufacture and
capable of being produced from readily available raw material.
Be relatively insensitive to shock or friction, yet able to positively detonate
by easily prepared initiators. Have the shattering effect and potential energy
adequate for the purpose. Be stable enough to retain usefulness for a
reasonable time when stored in any climate at temperatures between -80 and +165
degrees Fahrenheit. Have high density (weight per unit of volume).
Be suitable for use under water or in damp climates.
Have minimum toxicity (poisonous effects) when stored, handled, and detonated.
Be a convenient size and shape for packaging, storing, distributing, handling,
and emplacing by troops.
Have high energy output per unit of volume.


Detonation

The detonation or burning of all explosives produces poisonous fumes.
The chemicals used in explosives are poisonous.
Caution personnel against inhaling fumes or ingesting explosives.
When explosives are used in closed areas or underground, allow adequate time
for the fumes to dissipate before investigation.  Control the explosives to
prevent their use, such as burning as a source of heat or cooking, for other
than intended purpose.


Fire Hazards

Explosives contain their own oxidizer.  Burning explosives cannot be
extinguished by smothering or with water.  In fact, smothering will probably
cause and explosion.  Because of the possibility of detonation while explosives
are burning, observe the minimum safe distance.  WARNING: Personnel should not
attempt to extinguish burning explosives without expert advice and assistance.


Fire Safety Precautions for Transport

If fire breaks out in a vehicle transporting explosives, try to stop the
vehicle away form any populated buildings.  Stop traffic in both directions,
and warn drivers, passengers, and occupants of nearby buildings to keep at
least 2,000 feet away.  Inform police and firefighting authorities that the
cargo is explosives.  If a fire involves only the engine, cab, chassis, or
tires, make an effort to put out the fire with fire extinguishers, sand, dirt,
or water.  If the fire spreads to the body or cargo, STOP FIGHTING THE FIRE AND
EVACUATE THE AREA to a distance of at least 2,000 feet.
	
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