Quite simply, high explosives detonate. This means the “explosive shock front” occurs and passes through the explosive faster than the speed of sound. Velocity rates generally range from 3000 to 9000 meters per second.
High explosives, strictly speaking, fall under two classes:
Secondary high explosives & Primary high explosives
Primary high explosives are sensitive explosive substances used for detonating generally higher quantities of secondary high explosives. Applications include: detonator assemblies for blasting, primers, “det-cord” and other such initiating compounds. Primary explosives may be sensitive to impact, heat, electromagnetic radiation, friction, and static electricity. Some extremely sensitive substances are even sensitive to tiny amounts of air movement or temperature change.
Secondary high explosives are generally employed in most demolition, mining & military applications. Secondary high explosives are generally less sensitive explosive substances and require much more energy to detonate than primary explosives. Generally secondary explosives are safer to handle, store and generally use than primary explosives.
Velocity, sensitivity, reliability and general safety in use varies greatly depending on the explosive in question.
Commercially produced explosives have a good safety record provided they are being handled with the proper care. Homemade “improvised” high explosives have a horrendous rate of accidental detonation resulting in injury and death. Reasons for this are: the quality of source chemicals, the range of atmospheric conditions during production including presence of static electricity, lack of temperature and humidity control, impurities introduced through all stages of manufacture.
This section on high explosives contains one of the largest collections of high explosives related literature. This area focuses more on secondary explosives with our “primary explosives & detonators” section focusing on primary high explosives.