Technical development of explosion protection
The technical development of explosion protection dates back to the 19th century, when electrical equipment was introduced into industry and households. Immediately afterwards, the emergence of methane and coal dust during hard coal mining led to the development of the basics of electrical explosion protection. The advantages of electricity were so compelling that intensive work was undertaken to find a way to reliably prevent contact between explosive atmospheres and ignition sources arising from the use of electrical equipment, and thus prevent explosions.
These days, the construction of explosion-proof equipment goes far beyond electrical engineering. As will be shown in the following descriptions, non-electrical equipment will also need to be tested or at least assessed in the future. This is where the knowledge that manufacturers have gained over decades in the explosion protection of electrical equipment is particularly important, and now also benefits manufacturers of non-electrical equipment. These manufacturers often purchase electrical equipment that automatically creates contact.
Internationally agreed design norms for electrical engineering have been developed in the form of IEC standards, and reports have been produced that are largely in line with CENELEC standards. The number sequences used in IEC, CENELEC and DIN are currently being standardised. This reorganisation involves many ongoing changes at present, but will make work easier in the future.
In Directive 94/9/EC, the European Community has provided mandatory uniform design requirements for the explosion protection of systems, devices and components, and this directive is supported by the EN standards mentioned above and the CENELEC and CEN organisation standards.
Explosion and the basis for the explosion
An explosion is defined as a sudden reaction involving a rapid physical or chemical oxidation or decomposition reaction that results in an increase in temperature or pressure, or both. The best known are the reactions of combustible gases, vapours or dusts with oxygen in the air.
As a rule, three factors must be simultaneously present for explosions to occur in atmospheric air:
flammable substance (FS) oxygen (air) ignition source
Preventing explosions
Explosion-proof equipment can eliminate one of the preconditions for an explosion – the source of ignition – and thus makes an important contribution to explosion protection. In residential areas, construction measures ensure that an explosive atmosphere cannot be created. Deliberate restrictions on these measures, such as the intended unobstructed flow of flammable gases or reduced ventilation, can lead to explosions if an ignition source is also present.
The easiest and most straightforward way to understand small and safe explosions is to look at a gas lighter. When the nozzle of the lighter is opened, it releases a small amount of flammable gas. This gas mixes with the surrounding air, a spark from the flint ignites the mixture, and a faint sound is heard – burning. At a certain distance from the nozzle, the proportion of combustible gas is already so small that the explosion and flame are limited to the immediate vicinity of the nozzle. In other words, the design of the gas lighter ensures its safe use.
The effect of an explosion in enclosed spaces and in non-atmospheric conditions – for example, under high pressure – is often more powerful. Just think of the useful applications of explosions in car engines.
In order to achieve effective explosion protection against uncontrolled, unintentional explosions with catastrophic consequences, one of three factors must be eliminated.
BARTEC products prevent such sources from igniting or coming into contact with a potentially explosive atmosphere. They are effective in preventing explosions because the other two factors – oxygen in the air and often flammable substances – cannot be reliably and permanently excluded from the workplace.
The technical development of explosion protection dates back to the 19th century, when electrical equipment was introduced into industry and households. Immediately afterwards, the emergence of methane and coal dust during hard coal mining led to the development of the basics of electrical explosion protection. The advantages of electricity were so compelling that intensive work was undertaken to find a way to reliably prevent contact between explosive atmospheres and ignition sources arising from the use of electrical equipment, and thus prevent explosions.
These days, the construction of explosion-proof equipment goes far beyond electrical engineering. As will be shown in the following descriptions, non-electrical equipment will also need to be tested or at least assessed in the future. This is where the knowledge that manufacturers have gained over decades in the explosion protection of electrical equipment is particularly important, and now also benefits manufacturers of non-electrical equipment. These manufacturers often purchase electrical equipment that automatically creates contact.
Internationally agreed design norms for electrical engineering have been developed in the form of IEC standards, and reports have been produced that are largely in line with CENELEC standards. The number sequences used in IEC, CENELEC and DIN are currently being standardised. This reorganisation involves many ongoing changes at present, but will make work easier in the future.
In Directive 94/9/EC, the European Community has provided mandatory uniform design requirements for the explosion protection of systems, devices and components, and this directive is supported by the EN standards mentioned above and the CENELEC and CEN organisation standards.
Explosion and the basis for the explosion
An explosion is defined as a sudden reaction involving a rapid physical or chemical oxidation or decomposition reaction that results in an increase in temperature or pressure, or both. The best known are the reactions of combustible gases, vapours or dusts with oxygen in the air.
As a rule, three factors must be simultaneously present for explosions to occur in atmospheric air:
flammable substance (FS) oxygen (air) ignition source
Preventing explosions
Explosion-proof equipment can eliminate one of the preconditions for an explosion – the source of ignition – and thus makes an important contribution to explosion protection. In residential areas, construction measures ensure that an explosive atmosphere cannot be created. Deliberate restrictions on these measures, such as the intended unobstructed flow of flammable gases or reduced ventilation, can lead to explosions if an ignition source is also present.
The easiest and most straightforward way to understand small and safe explosions is to look at a gas lighter. When the nozzle of the lighter is opened, it releases a small amount of flammable gas. This gas mixes with the surrounding air, a spark from the flint ignites the mixture, and a faint sound is heard – burning. At a certain distance from the nozzle, the proportion of combustible gas is already so small that the explosion and flame are limited to the immediate vicinity of the nozzle. In other words, the design of the gas lighter ensures its safe use.
The effect of an explosion in enclosed spaces and in non-atmospheric conditions – for example, under high pressure – is often more powerful. Just think of the useful applications of explosions in car engines.
In order to achieve effective explosion protection against uncontrolled, unintentional explosions with catastrophic consequences, one of three factors must be eliminated.
BARTEC products prevent such sources from igniting or coming into contact with a potentially explosive atmosphere. They are effective in preventing explosions because the other two factors – oxygen in the air and often flammable substances – cannot be reliably and permanently excluded from the workplace.
