information:classification, structural:expansion
Low

Low explosives (or low-order explosives) are compounds wherein the rate of decomposition proceeds through the material at less than the speed of sound. The decomposition is propagated by a flame front (deflagration) which travels much more slowly through the explosive material than a shock wave of a high explosive. Under normal conditions, low explosives undergo deflagration at rates that vary from a few centimetres per second to approximately 0.4 kilometres per second (1,300 ft/s). It is possible for them to deflagrate very quickly, producing an effect similar to a detonation. This can happen under higher pressure (such as when gunpowder deflagrates inside the confined space of a bullet casing, accelerating the bullet to well beyond the speed of sound) or temperature.

A low explosive is usually a mixture of a combustible substance and an oxidant that decomposes rapidly (deflagration); however, they burn more slowly than a high explosive, which has an extremely fast burn rate.

Low explosives are normally employed as propellants. Included in this group are petroleum products such as propane and gasoline, gunpowder (including smokeless powder), and light pyrotechnics, such as flares and fireworks, but can replace high explosives in certain applications, including in gas pressure blasting.