Sensitivity (explosives)

In explosives engineering, sensitivity refers to the degree to which an explosive can be initiated by impact, heat, or friction. 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 and brisance 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 detonators, such as blasting caps. The use of increasingly less sensitive explosive materials to create an escalating chain reaction is known as an explosive train, initiation sequence, or firing train.

Classifications
High explosives are conventionally subdivided into two explosives classes, differentiated by sensitivity: The dataset for 150 CHNOFCl energetic compounds is available.
 * Primary explosives 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.