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BLASTWRAP® TERMINOLOGY
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Afterburn
Afterburn is the arithmetic difference between heat (energy) of detonation and the heat (energy) of combustion. If there is enough oxygen present in a blast, carbon monoxide and carbon (soot) can burn. The energy release for TNT and many propellants can be up to 5 times greater than the detonation energy.
Ammonium Nitrate / Fuel Oil (ANFO)
A crude but effective explosive that is used by farmers to clear stumps and by the mining industry (because it is easy to pump in slurry form) to break up overburden rock and expose ore in open pit mining.
Ballistic Impact
Ballistic Impact refers to initiating a unit of ammunition or other energetic material in the event of an impact by a ballistic threat such as a bullet or other high velocity projectile.
Biological Warfare
Also known as germ warfare, is the use of any organism (bacteria, virus or other disease-causing organism) or toxin found in nature, as a weapon of war.
Blast Suppression
A system to protect critical structures from blast effects by decreasing the energy output of the explosion.
Bomb Disposal
A term for making explosive devices safe by disarming or detonating them.
C-4
A common variety of military plastic explosive. C-4 is made up of explosive, binder, plasticizer and (latterly) marker or taggant chemicals. As in many plastic explosives the explosive material in C-4 is RDX (Cyclonite, cyclotrimethylene trinitramine) which makes up around 90% of the C-4 by weight. The binder is polyisobutylene (5.5%) and the plasticizer is di(2-ethylhexyl) or dioctyl sebacate (2%). In the U.S., the marker is DMDNB (2, 3-dimethyl-2, 3-dinitrobutane). Another binder used is dioctyl adipate (DOA). A small amount of petroleum oil is also added.
Chemical Warfare
The use of non-explosive chemical agents (that are not themselves living organisms) to cause injury or death.
Deflagration
Chemical reaction of a substance in which the reaction front advances into the unreacted substance at less than sonic velocity. Where a blast wave is produced that has the potential to cause damage, the term explosive deflagration may be used.
Detonation
Release of energy caused by the extremely rapid chemical reaction of a substance in which the reaction front advances into the unreacted substance at equal to or greater than sonic velocity.
Detonator
Used to trigger bombs, shape charges and other forms of explosive device. Detonators are often attached to a timer to ensure that the explosion takes place at the desired time, or when the person laying the explosives has reached a safe distance from the blast. Detonators can be chemical, mechanical, or a combination. Many detonators' primary (sensitive to heat and shock) explosive is a material called tetryl.
Dynamite
An explosive used in mining, demolitions, and other applications. It was invented by Alfred Nobel in 1867, and rapidly gained popularity as a safer alternative to gunpowder, because it does not explode by accident as easily.
Explosion
Release of energy that causes a pressure discontinuity or blast wave.
Explosive Ordnance Disposal (EOD)
The task of rendering safe and disposing of any explosive material. A military term which includes both dealing with improvised explosive devices and unexploded ordnance.
Fast Cook Off
Fast Cook Off concerns the initiation of a unit of ammunition or other energetic store in the event of a flash fire such as a fuel fire.
High-Order Explosions
High-order explosions release a lot of heat and produce shock waves. About 50% of the energy in a blast goes to heat and 50% goes to shock waves.
Impulse
Impulse is the momentum (mass x velocity) imparted in a blast and is determined by the area under the pressure-time curve.
Improvised Explosive Device (IED)
A term used to describe a homemade bomb or homemade explosive booby trap. An IED typically consists of an explosive charge, possibly a booster charge, a detonator and a mechanism either mechanical or electronic, known as the initiation system.
Insensitive Munition (IM)
Munitions which reliably fulfill their performance, readiness and operational requirements on demand, but which minimize the probability of inadvertent initiation and severity of subsequent collateral damage to weapon platforms, logistic systems and personnel when subjected to unintentional stimuli. IM are munitions which: burn when subjected to fast or slow heating, bullet or fragment attack; and do not detonate when subjected to shape charge jet impact or when another munition detonates in a stack.
Landmine (IM)
A type of mine which is placed on the ground and explodes when triggered by a vehicle or person.
LD3 Containers (IM)
A standardized container used for loading freight into aircraft. The base is smaller than the top, allowing the container to fit snugly inside the lower deck of a wide body airliner, with base dimensions of 61.5" x 60.4"; top dimensions of 79" X 60.4"; height of 64"; and volume of 159 ft².
Mitigation (IM)
Lessening the risk of an accident event sequence by acting on the source in a preventive way by reducing the likelihood of occurrence of the event, or in a protective way by reducing the magnitude of the event and/or the exposure of local persons or property.
M998 High Mobility Multipurpose Wheeled Vehicle (HMMWV or Hum-Vee)
A highly durable military motor vehicle. It has largely supplanted the role formerly served by the jeep with the United States military.
Nitroglycerin
A heavy colorless poisonous oily explosive liquid obtained by nitrating glycerol. It is used in the manufacture of explosives, specifically dynamite, and as such is employed in the construction and demolition industries.
Overpressure (or Peak Pressure)
Overpressure (or peak pressure) appears approx. 1/10th to 5 milliseconds after detonation, depending on scaled distance. Safety standards for buildings and inhabited areas are typically based on maximum peak pressures.
Pipe Bombs
Is any homemade explosive device encased in a piece of ordinary plumbing pipe. The pipe makes a convenient container for the bomb, and creates shrapnel when it explodes.
Plastic Explosive
A specialised form of explosive material. They are soft and hand malleable and may have the added benefit of being usable over a wider temperature range than the pure explosive. Plastic explosives are especially suited for explosive demolition as they can be easily formed into the best shapes for cutting structural members, and have a high enough velocity of detonation and density for metal cutting work. They are generally not used for ordinary blasting as they tend to be significantly more expensive than other materials that perform just as well in that field. Also, when an explosive is bound in a plastique, its power is generally lower than when it is pure.
Quasi-Static Pressure
Quasi-static pressure is a major effect in a confined blast. In a room or large space gas pressure will build up to a fairly constant level; however, in a confined space gas pressure just builds until either the walls blow out (vent) or the confined hot gas cools down. The pressure determines required hoop strength in containers and buildings.
Reflected Overpressure
Reflected overpressure theoretically runs from 2 to 8 times incident pressure in free air.
Scaled Distance
Scaled distance is the main way of comparing different blasts. The definition is:
| Scaled Distance Z (Scaled Distance) = |
R (Distance from Charge) |
| ----------------------------------------- |
W (TNT Net Equivalent Charge Weight)  |
Or, Scaled Distance is equal to the Distance from Charge divided by the cube root of the TNT Net Equivalent Charge Weight. |
Slow Cook Off
Slow Cook Off refers to the initiation of a unit of ammunition or other energetic material in the event of a slower but more sustained thermal event.
Sympathetic Detonation
Sympathetic Detonation results when one detonating unit or energetic material initiates the next, and so on, in a chain like reaction. Sympathetic detonation is the product of an internal high pressure event being initiated in a store of material. This high pressure event can be caused by the impinging of a shock wave or by the impact of a primary or secondary fragment from detonating adjacent munitions.
Tetryl
A sensitive explosive compound used to make detonators. It has a slight yellow color, and decomposes at 129°C. Its relative density is 1.73. It is produced by action of a mix of concentrated nitric acid and sulfuric acid on dimethylaniline.
Trinitrotoluene (TNT)
A pale yellow crystalline aromatic hydrocarbon compound that melts at 81 °C (178 °F). Trinitrotoluene is an explosive chemical and a part of many explosive mixtures, such as when mixed with ammonium nitrate to form amatol.
Unconfined Vapor Cloud Explosion (UCVE)
Explosive oxidation of a vapor cloud in a nonconfined space (i.e., not in vessels, buildings, etc.). The flame speed may accelerate to high velocities and produce significant blast overpressure. Vapor cloud explosions in densely packed plant areas (pipelines, unites, etc.) may show accelerations in flame speeds and intensification of blast.
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