Explosive

see also: Etymology of Explosive

An explosive is a definite Composé chemical or a likely mixture of body at the time of their transformation, to release in a time a relatively short, great volume of Gaz carried to high Température, which constitutes a Explosion. From that creation results from a Wave front of pressure. The speed of this wave front determines the classification of the explosives.

There exist two great groups of explosives:

the powders (mode of Deflagration);
explosive breaking (mode of Detonation).

The difference between the modes of deflagration and detonation is not always simple. According to the conditions of use, an explosive normally deflagrating can explode, and an explosive normally explosive can deflagrate. The powders are designed for a mode of deflagration, i.e. a subsonic wave (of 10 with 400 m·S −1 ). The progressive explosives are located between the powders and breaking them. They follow the mode of detonation, supersonic (of: 2000 with: 3500 m.s −1 ). High-strength explosives also explode (of: 4000 with: 9000 m.s −1 ).

The explosives can also be used for the propulsion of projectiles or rockets in the form of powder or Propellent. The mode is then the Combustion which must be very well controlled. (example the 2 booster rockets has powders of each dimensioned ARIANE rocket)

Deflagrating explosive

the Blasting powder, especially used for the gun S of formerly, the Fireworks S and the Detonator S.
white powder (Nitrocellulose), used also in some jet engine.
mixtures “easy to realize”: mixtures containing current products like the Fuel, Manure or Lessive are sometimes used by Terroriste S to perpetrate Attentat S.

High-strength explosive

High-strength explosives have a rate detonation which exceeds: 6050 m/s. Most powerful known atteind rate detonation of 9200 m/s. One can quote among them the nitros groups and nitrates, peroxides organic, chlorates and perchlorates, halides of nitrogen, the azides and fulminates.

They are generally used in the military field or the building. For pyrotechny, one will prefer the deflagrating explosives, because breaking them are too complex to handle. Moreover, they are often very toxic and even sometimes carcinogenic.

In civil engineering, the Nitroglycerin, too unstable, is unusable in its current liquid form. This one has its most spread use in medicine, because it is a powerful vasodilatator. One generally prefers the Dynamite to him, which is nitroglycerin stabilized by addition of one stabilizing. In XXIe century, the explosives known as plastic, composed of explosive and of gelatinizing (in order to “flegmatiser” active matter), are used.

In military engineering, several explosives are used:

the pure mélinite (known under the name of picric acid or even of 2,4,6-trinitrophenol) is not any more used nowadays, but is used as standard to give the load factor practices (CUP) of an explosive, measuring its power.
TNT was largely used during the Second world war.
Hexolite
Trotile or Tolite which, combined with a clashing Chalk line, proves very effective in a directional application.
Octolite (exclusive military use), one can also add powder aluminum to increase the power of the breath.

History

The Gunpowder, only explosive known until the 18th century, contained Salpêtre, Soufre and Charcoal. In 1846, one used the Fulmicoton, of the Nitrocellulose stabilized synthesized by Christian Schönbein.

In 1847, the Nitroglycerin, discovered by Ascanio Sobrero, proved extremely dangerous of use and will be built-in a support like nitrocellulose to give the Dynamite, whose discovery, in 1867, is due to Alfred Nobel and constitutes the base of the modern explosive first. Nobel did not use nitrocellulose to create dynamite, but a porous matter called kieselguhr , capable of “flegmatiser” nitroglycerin.

Formation and regulation

For safety reasons of the users and fight against the Terrorism, the implementation of explosives requires to follow a formation and to respect the regulations in force in the country.

It is necessary to have authorizations and to be titular of a license or a certificate. These diplomas prepare during a formation by an approved organization. They are obtained after success with an examination.

It is in general interdict with the users to manufacture explosives. The latter must get them near manufacturers who market only products having received a technical approval.

The user will have to also comply with the rules concerning the transport and the storage of the explosives.

Dangers

The approved explosives are sure products, but can present dangers if the security instructions are not respected during their use:

accidental activation of sensitive elements like the detonators following a shock, of an electromagnetic disturbance
intoxication due to the carbonization gases by the explosive in a medium badly ventilated
intoxication by contact with the skin by handling the products
safety zone not respected
projection or destabilization of rocks and other materials
incidental during a shooting requiring an intervention of the bomb disposal expert on a device damaged

Note: the primary education explosives as the powders are tellements sensitive that they can react with the only static electricity generated by the human body or frictions.

Specific dangers of the made explosives house

The made explosives improvised house, or explosive devices (DEI), can present dangers to the user during their manufacture, their transport or their use. Certain mixtures are unstable, they explode or ignite spontaneously at low temperatures (40°C), or at the time of a weak shock, or after a certain amount of time. The operator can be wounded (torn off hand, burns, burst eye, hearing impairment, intoxication) or killed. These machines or mixtures can cause wounds with other people and cause important property damages (puffed up walls and panes, fire).

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