What is an explosion? This is a process of instantaneous transformation of the state of an explosive, in which a significant amount of thermal energy and gases are released, forming a shock wave.
Explosives are compounds that have the ability to undergo changes in physical and chemical state as a result of external influences with the formation of an explosion.
Classification of explosion types
1. Physical - the energy of an explosion is the potential energy of a compressed gas or steam. Depending on the magnitude of the internal energy pressure, an explosion of different power is obtained. The mechanical impact of the explosion is due to the action of the shock wave. Fragments of the shell cause an additional lethal effect.
2. Chemical - in this case, the explosion is due to the almost instantaneous chemical interaction of the substances that make up the composition, with the release of a large amount of heat, as well as gases and steam with a high degree of compression. Explosions of these types are typical, for example, for gunpowder. Substances formed as a result of a chemical reaction acquire high pressure when heated. The explosion of pyrotechnics also belongs to this species.
3. Nuclear explosions are lightning-fast reactions of nuclear fission or fusion, characterized by a huge power of released energy, including heat. The colossal temperature at the epicenter of the explosion leads to the formation of a zone of very high pressure. Expansion of the gas creates a shock wave that causes mechanical damage.
The concept and classification of explosions allow you to act correctly in an emergency.
Action type
Explosives by type of action are classified into the following types:
- condensed;
- voluminous.
The first type is such compounds that, being under normal conditions in a solid or liquid state of aggregation, can, under external influence, start a transformation reaction, accompanied by the appearance of superheated vapors and gases with the formation of a stable high-pressure zone. A sharp expansion of the gaseous medium leads to the occurrence of a shock effect. Such reactions are called explosive transformation.
In order to start a reaction, it is necessary to give the explosives some initial energy of a mechanical, thermal, electrical, chemical or other type.
Explosive Groups
There are three main groups of condensed explosives.
| Properties | |
| I |
Highly dangerous explosives. Prone toentry into the transformation reaction, are unstable. They are dangerous even in small quantities. Examples: copper(I) acetylenide, nitrogen trichloride. |
| II |
Primary explosives. More stable compared to group I. Easily detonated from mechanical or thermal action from the outside. Often used in detonators. Examples: lead azide, mercury(II) fulminate. |
| III |
Secondary explosives. Initiation of an explosion occurs only with a strong external impact, for example, from detonation. Relatively stable and provide for long-term storage, warehousing is possible. Examples: dynamite, TNT. |
| IV |
Gunpowder Explosions are very stable, weakly react to external mechanical impact. Initiated from heat. May burn or explode (in case of closed circuit) depending on environmental conditions. |
Distinguishing Features
Explosions differ depending on the ongoing chemical reactions:
- Decomposition is characteristic of a gaseous medium.
- Redox processes involve the presence of a reducing agent with which airborne oxygen will react.
- Reaction of mixtures.
Volume explosions include dust explosions, as well as steam cloud explosions.
Dust explosions
They are typical for closed dusty structures, such as mines. dangerous concentrationExplosive dust appears during mechanical work with bulk materials that give a large amount of dust. Working with explosives requires full knowledge of what an explosion is.
For each type of dust there is a so-called maximum permissible concentration, when exceeded, there is a risk of spontaneous explosion, and this amount of dust is measured in grams per cubic meter of air. The calculated concentration values are not constant values and must be adjusted depending on humidity, temperature and other environmental conditions.
Special danger is the presence of methane. In this case, there is an increased probability of detonation of dust mixtures. Already a five percent content of methane vapor in the air threatens to explode, due to which the ignition of a dust cloud follows and an increase in turbulence. A positive feedback occurs, leading to an explosion of great energy. Scientists are attracted to such reactions, the explosion theory still haunts many.
Safety when working in confined spaces
When working in enclosed spaces with a high content of dust in the air, it is imperative to adhere to the following safety rules:
- dust removal by ventilation;
- fight against excessive air dryness;
- dilution of the air mixture with inert gases to reduce the concentration of explosives.
Dust explosions are typical not only for mines, but also for buildings, andgranaries.
Explosions of steam clouds
They are reactions of a lightning-fast change of state, generating the formation of a blast wave. Occur outdoors, in a confined space due to the ignition of a combustible vapor cloud. As a rule, this happens when liquefied gas leaks.
For your safety, it is recommended that you carefully observe the following precautions:
- Refusal to work with flammable gas or steam;
- rejection of ignition sources that can cause a spark;
- avoiding confined spaces.
You need to have a sound understanding of what an explosion is, what danger it carries. Failure to comply with safety rules and the illiterate use of some items leads to disaster.
Gas explosions
The most common gas explosion accidents occur as a result of improper handling of gas equipment. Timely elimination and characteristic definition are important. What does gas explosion mean? It happens due to improper operation.
In order to prevent such explosions, all gas equipment must undergo regular preventive maintenance. All residents of private households, as well as apartment buildings, are recommended an annual MOT VDGO.
To reduce the consequences of an explosion, the structures of the premises in which gas equipment is installed are made not capital, but, on the contrary, lightweight. ATin the event of an explosion, no major damage and blockages occur. Now you imagine what an explosion is.
To make household gas leaks easier to detect, the aromatic additive ethyl mercaptan is added to it, which causes a characteristic smell. If there is such a smell in the room, it is necessary to open the windows to ensure the supply of fresh air. Then you should call the gas service. At this time, it is better not to use electrical switches that can cause a spark. Strictly no smoking!
Explosion of pyrotechnics can also become a threat. The storage of such items must be equipped in accordance with the standards. Poor quality products can harm the person who uses it. All this should definitely be taken into account.
