explosives engineering Explosives engineering is the field of science and engineering which is related to examining the behavior and usage of explosive materials. Topics Some of the topics that explosives engineers study, research, and work on include: * Developmen ...

, sensitivity refers to the degree to which an

explosive An explosive (or explosive material) is a reactive substance that contains a great amount of potential energy that can produce an explosion if released suddenly, usually accompanied by the production of light, heat, sound, and pressure. An ex ...

can be initiated by impact,

heat In thermodynamics, heat is energy in transfer between a thermodynamic system and its surroundings by such mechanisms as thermal conduction, electromagnetic radiation, and friction, which are microscopic in nature, involving sub-atomic, ato ...

, or

friction Friction is the force resisting the relative motion of solid surfaces, fluid layers, and material elements sliding against each other. Types of friction include dry, fluid, lubricated, skin, and internal -- an incomplete list. The study of t ...

. Current in-use standard methods of mechanical (impact and friction) sensitivity determination differ by the sample preparation (constant mass or volume is usually used; pile or pressed pellet), sample arrangement (confined/unconfined sample etc), instrument type, go/not go criteria, and the statistical analysis of results. Sensitivity,

stability Stability may refer to: Mathematics *Stability theory, the study of the stability of solutions to differential equations and dynamical systems ** Asymptotic stability ** Exponential stability ** Linear stability **Lyapunov stability ** Marginal s ...

and

brisance Brisance (; ) is the shattering capability of a high explosive, determined mainly by its detonation pressure. Application Brisance is of practical importance in explosives engineering for determining the effectiveness of an explosion in blasti ...

are three of the most significant properties of explosives that affect their use and application. All explosive compounds have a certain amount of energy required to initiate, analogous to the minimum ignition energy of fuel-air mixtures. If an explosive is too sensitive, it may go off accidentally. A safer explosive is less sensitive and will not explode if accidentally dropped or mishandled. However, such explosives are more difficult to initiate intentionally.

Explosive train

Less sensitive explosives can be initiated by smaller quantities of more sensitive explosives, called primers or

detonator A detonator is a device used to make an explosive or explosive device explode. Detonators come in a variety of types, depending on how they are initiated (chemically, mechanically, or electrically) and details of their inner working, which of ...

s, such as

blasting cap A detonator is a device used to make an explosive or explosive device explode. Detonators come in a variety of types, depending on how they are initiated (chemically, mechanically, or electrically) and details of their inner working, which of ...

s. The use of increasingly less sensitive

explosive materials An explosive (or explosive material) is a reactive substance that contains a great amount of potential energy that can produce an explosion if released suddenly, usually accompanied by the production of light, heat, sound, and pressure. An exp ...

to create an escalating

chain reaction A chain reaction is a sequence of reactions where a reactive product or by-product causes additional reactions to take place. In a chain reaction, positive feedback leads to a self-amplifying chain of events. Chain reactions are one way that sys ...

is known as an explosive train,

initiation sequence Initiation is a rite of passage marking entrance or acceptance into a group or society. It could also be a formal admission to adulthood in a community or one of its formal components. In an extended sense, it can also signify a transformatio ...

, or

firing train Firing may refer to: * Dismissal (employment), sudden loss of employment by termination * Firemaking, the act of starting a fire * Burning; see combustion * Shooting, specifically the discharge of firearms * Execution by firing squad, a method of ...

Classifications

High explosives An explosive (or explosive material) is a reactive substance that contains a great amount of potential energy that can produce an explosion if released suddenly, usually accompanied by the production of light, heat, sound, and pressure. An exp ...

are conventionally subdivided into two explosives classes, differentiated by sensitivity: *

Primary explosive An explosive (or explosive material) is a reactive substance that contains a great amount of potential energy that can produce an explosion if released suddenly, usually accompanied by the production of light, heat, sound, and pressure. An exp ...

s are extremely sensitive to mechanical shock, friction, and heat, to which they will respond by burning rapidly or detonating. * Secondary explosives, also called base explosives, are relatively insensitive to shock, friction, and heat. The dataset for 150 CHNOFCl energetic compounds is available.

References

Explosives {{explosive-stub