Common Terms

A complete glossary of terms dealing with fire and explosions is maintained online by the Technical Working Group for Fire and Explosions (TWGFEX).

Base Charge - The main high explosive charge in a blasting cap.

Binary Explosive - Two substances which are not explosive until they are mixed.

Black Powder - A low explosive traditionally consisting of potassium nitrate, sulfur and charcoal. Sodium nitrate may be found in place of potassium nitrate.

Blasting Agent - A high explosive with low sensitivity usually based on ammonium nitrate and not containing additional high explosive(s).

Blasting Cap - A metal tube containing a primary high explosive capable of initiating most explosives.

Bomb - A device containing an explosive, incendiary, or chemical material designed to explode.

Booby Trap - A concealed or camouflaged device designed to injure or kill personnel.

Booster - A cap-sensitive high explosive used to initiate other less sensitive high explosives.

Brisance - The shattering power associated with high explosives.

C4 - A white, pliable military plastic explosive containing primarily Cyclonite (RDX).

Cannon Fuse - A coated, thread-wrapped cord filled with black powder designed to initiate flame-sensitive explosives.

Combustion - Any type of exothermic oxidation reaction, including, but not limited to burning, deflagration and/or detonation.

Deflagration - An exothermic reaction that occurs particle to particle at subsonic speed.

Detonation - An exothermic reaction that propagates a shockwave through an explosive at supersonic speed (greater than 3,300ft/sec).

Detonation Cord (“Det-Cord”) - A plastic/fiber-wrapped cord containing a core of PETN or RDX.

Detonator - A device used for detonating many types of high explosives.

Double Base - A smokeless powder which contains both nitroglycerine and nitrocellulose.

Dud - An explosive device which has undergone a complete arming and firing cycle but has failed to explode. It should be noted that this is a very dangerous situation.

Dynamite - Originally, a mixture of nitroglycerine and an absorbent filler now used to designate an entire class of high explosives.

Electric Match - A metal wire coated with a pyrotechnic mixture designed to produce a small burst of flame designed to initiate a low explosive.

Electric Squib - A metal wire surrounded by a pyrotechnic mixture and encased within a metal tube which produces a small jet of flame designed to initiate a low explosive.

Explosion - A rapid expansion of gases resulting from a chemical or physical action that produces a pressure wave.

Explosive - A chemical substance or mixture capable of producing an explosion.

Explosive Compound - A single chemical compound capable of causing an explosion.

Explosive Mixture - A mixture of chemical compounds capable of causing an explosion.

Explosive Ordnance Disposal (EOD) - Bomb squad; term generally used more for a military context.

Explosive Precursor - Any chemical material that can be mixed with one or more other chemical substances that consist of fuels and oxidizers that result in the intended production on an explosive.

Explosive Train - A series of combustible or explosive components arranged in order of decreasing sensitivity designed to initiate explosives.

Frag - Any item(s) produced and cast away from an explosion.

Fuel - Any substance capable of reacting with oxygen or oxygen-carriers (oxidizers).

Fuse - A fiber-wrapped cord of black powder used to initiate blasting caps or low explosives.

Fuze - A mechanical, chemical, or electrical device designed to initiate an explosive train.

Gunpowder - See “Black Powder”.

High Explosive - Generally a chemical substance or mixture capable of detonation.

Hoax - A “dummy” device intended to appear as a bomb but not containing an explosive.

Improvised Explosive Device (IED) - A non-commercially produced device designed to explode.

Incendiary - A compound, metal or mixture capable of producing intense heat.

Inert - A simulated explosive or device that contains no explosive, pyrotechnic, or chemical/biological agent.

Initiator - The part of an explosive train which starts the reaction.

Low Explosive - Generally a chemical compound or mixture that can deflagrate without the addition of atmospheric oxygen.

Main Charge - The main or final explosive in an explosive train.

Munitions - Any and all military explosives.

Ordnance - See “Munitions”.

Oxidizer - A chemical compound that supplies the oxygen in a chemical reaction.

PETN - Pentaerythritoltetranitrate, a high explosive used in many applications.

Plastic Bonded Explosives (PBX) - A high explosive in a pliable plastic matrix (e.g., C4, Det Flex)

Plastic Explosives - Common term for PBX.

Primary High Explosive - A high explosive sensitive to heat, shock, spark, and/or friction.

Primer - See “Initiator”.

Primer cap - A small metal device containing an impact-sensitive primary high explosive commonly found in ammunition or used in initiators.

Pyrotechnic Fuse - See “Cannon Fuse”.

Pyrotechnic Mixtures - An oxidizer/fuel mixture which produces bright or colored lights, heat, fogs, or acoustic effects.

Report - A loud sound produced by an explosion.

Safety Fuse - A water-proof coated, thread-wrapped cord filled with black powder designed to be used to initiate a non-electric blasting cap.

Secondary High Explosive - A less-sensitive high explosive initiated by another explosive.

Shaped Charge - An explosive device which is designed to direct or focus explosive energy into a narrow jet. The created plasma has a synergistic effect increasing the heat and energy on the target area.

Shrapnel - Objects which are attached to the outside or included inside a device to increase the blast damage and/or injure/kill personnel. The device/container walls themselves can also function in this manner.

Single Base - A smokeless powder which contains nitrocellulose but does not contain nitroglycerine or nitroguanidine.

Smokeless Powder - A low explosive used in ammunition as a propellant, which can be single-, double-, or triple-based

TNT - Trinitrotoluene, a commonly used explosive that is especially useful because of its low risk for accidental detonation.

Triple Base - A smokeless powder which contains nitrocellulose, nitroglycerine, and nitroguanidine.

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