Explosives: Types, Classification and its Uses

An explosive is a substance (an element or compound or a mixture) or device which is made to produce a volume of rapidly expanding gas in an extremely brief period of time. It is a substance which is capable of exerting pressure on its surroundings on explosion or transformation.

Explosion can be defined as the rapid increase of the volume and release of high energy in a particular area due to expansion of high-energy gases. The device used to create an explosion is called an explosive.

In India the definitions and rules related to explosives are described in the Indian Explosive Act, 1884.

Fundamentally they are of three types i.e., mechanical, chemical and nuclear.

1. Mechanical Explosives– A mechanical explosion requires the physical reactions to occur, which involves high-pressure gas expanding in the container beyond the tensile strength of the container and bursting it, releasing the pressure and producing shock waves. A fine example of Mechanical explosive is an overheating cooker.
2. Chemical Explosives– A chemical explosion occurs due to the exothermic decomposition or combination reactions of the chemical compounds within the explosive device. The reactions release high pressure gases which produce shock waves. An example of Chemical explosive are picric acid, TNT, RDX, etc.
3. Nuclear Explosives– A nuclear explosion is the result of the fission or fusion reactions within the explosive devices. The reaction produces a large amount of heat and gas very rapidly in the surrounding air which creates huge blast waves. An example of Nuclear explosive is hydrogen bomb.

Classification of Explosives

The further classification of the explosive is based on their speed of explosion. These can be categorized as low and high explosives.

1. Low Explosives

These are responsible for deflagrating reactions in which the substances burn rapidly rather than bursting. They produce enormous amounts of gases and energy which is useful for forcing a projectile in a particular direction. They include:-

• Gunpowder– It is a mixture of potassium nitrate, charcoal and sulphur in proportion of 75:15:10 respectively. It is used as a propellent in the firearms, as an explosive in crude bombs, etc.
• Pyrotechnics– It includes the mixtures based upon mainly gunpowder, barium nitrate, nitrate mixtures, aluminium powder, magnesium powder, etc. The fireworks are examples of pyrotechnics. They are capable of converting fire into a burst of fireworks or the cloud of smoke clogs.

2. High Explosives

They produce detonation reactions that is they decompose at a high speed and shatter the container as well as the surroundings. These can be further classified on the basis of their sensitivity. They are:

• Primary Explosives– These are extremely sensitive to mechanical shocks, heat, friction and burns rapidly. Its example include mercury fulminate, lead azide, mercury styphnate, etc. They are used in detonators, primers or as boosters.
• Secondary Explosives– These are less sensitive than the primary explosives and are called base explosives. They can be ignited by the exposure to heat or flame in trivial, liberated quantities. Its example include RDX, TNT, HMX, PETN, etc. They are used in military purposes, industrial blasts, etc. They are of two types- boosters and main charge.

1. Boosters act as a bridge between a low energy and low sensitivity explosive. Examples- TNT, RDX and PETN.
2. Main Charge is also called dynamite and divided into gelatin and non gelatin dynamite.

3. Miscellaneous Explosives

These are usually divided into two categories i.e.,

• Homemade Explosives:- The most commonly made homemade explosive include a molotov cocktail which consists of a bottle half-filled with flammable liquids (gasoline or alcohol), the mouth of the bottle capped with the cork tightly and a cloth soaked in the flammable liquid is wrapped around the mouth. They are usually used in local riots.
• Improvised Explosive Devices (IEDs):- They are the products assembled in contravention to the existing rules of law of the nation adopting unconventional or semi-conventional methods of formulating explosives with a criminal or anti-national intent. IEDs include briefcase bomb, letter bomb, tiffin bomb, etc.

Uses of Explosives

Their use can be legal and illegal depending upon the purpose of the use. The uses can be:

• Legitimate Use– When the explosives are used in the mining, oil explorations, military purposes, satellite propulsions, roads and railway constructions, etc.
• Illegitimate Use– Illegal use of explosives for creating threat and nuisance among the general public. Usually used by the criminals against an individual and terrorists against a nation. The illegitimate use is punishable according to Indian Penal Code under Explosive Act and The explosive substances Act.

Conclusion

Explosives are very dangerous substances which threaten the integrity of a nation as well as of an individual. The laws for their illegal use are formed and executed by the government to ensure the security of the individuals and the nation.

Due to the information about manufacturing of bombs, available to almost all individuals doesn’t help in restricting its uses with common explosives like molotov can even be made by youngsters with a little practice.

Strict monitoring of their use is required yet is not sufficient to restrict them from being used in any country.