IEC Hazardous Zones
What Are Hazardous Area Standards?
One of the greatest safety hazards in industrial settings are explosions or fires, creating the need for explosion proof equipment. The International Electrotechnical Commission (IEC) has developed a set of regulations, the Zone system, for hazardous areas. These standards are used throughout Europe and most of the world (except for the United States) and help to classify areas where potentially dangerous explosive conditions exist. These standards are based on two components— zones and groups.
Hazardous Zones
Zones describe the type of hazardous material. They also determine the likelihood of the hazardous material in the atmosphere. The zone system has three levels for gas (Zone 0, Zone 1, Zone 2) and another three levels for dust (Zone 20, Zone 21, Zone 22).
The standards classify hazardous area zones as following:
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Zone 0/20 |
Areas constantly susceptible to an explosive atmosphere for long periods of time. |
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Zone 1/21 |
Areas where an explosive atmosphere is likely to develop during normal conditions. |
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Zone 2/22 |
Areas rarely susceptible to an explosive atmosphere and for a short period of time. |
Hazardous Groups
The standards classify electrical equipment into two groups:
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Group I |
Electrical apparatus to be installed in mines or galleries susceptible to firedamp or coal dust. |
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Group II |
Electrical apparatus to be installed in surface plants susceptible to other explosive atmospheres. |
IEC Standards in Practice
The IEC’s Zone System requires manufacturers of electrical equipment to design products that are explosion proof and safe. These designs are tested, and successful designs are issued conformity certificates stating they meet the required safety standards.
In applications in oil and gas, mining, and marine industries, it is important to choose the right equipment. Following the IEC standards and selecting equipment that has been designed and tested for the hazardous area is required. Explosion-proof or flame-proof equipment is sealed and rugged to a degree that it will not ignite in any hazardous atmosphere and is ideal to use when sparks might be present.