Gas Zones

Gas,vapors

Zones 0
A zone in which an explosive atmosphere consisting of a mixture of air with inflammable substances in the form of gas, vapor, or mist is present continuously or for a long time or frequently (EN 60079-10-1).
Zone 0 mainly covers the interior of closed containers, pipes, and apparatus containing inflammable liquids. Here, the corresponding operating temperature is above the ignition point, and the danger zone is above the surface of the liquid, not in it.
Most gases of flammable liquids are heavier than air and propagate similarly to liquids. In cavities such as the pump’s pit and sump, these explosive gases can usually reside for a longer time, so it is necessary to reckon on Zone 0 here.
In Zone 0 equipment, ignition sources must be protected from an explosion, even if failures are infrequent.
In the event of failure of one type of protection or simultaneous occurrence of two faults, sufficient explosion protection must be provided.
According to the design requirements of DIN EN 60079-26 (VDE 170/0171/ Part 12-1), the necessary explosion protection is achieved if the equipment is designed under the type of protection “ia” according to EN 60079-11, Intrinsic safety, or satisfies the requirements of two types of protection series EN 60079, which operate independently of each other.
For this reason, for example, flame-retardant luminaires were additionally hermetically sealed or intrinsically safe devices in protection type “ib” in pots.
According to Directive 014/34/EU, equipment for Zone 0 must meet the requirements of category 1G. In Zone 0, the risk of ignition due to electrostatic charges, even in rare cases, must be reliably excluded. For this reason, the requirements of EN 0079-0 for equipment for use in Zone 0 are significantly higher than those for equipment for Zone 1.

Zone 1
A zone in which an explosive gaseous atmosphere consisting of a mixture of air with inflammable substances in the form of gas, vapor, or mist may occur from time to time during regular operation (EN 60079-10-1).
In Zone 1, inflammable or explosive substances are produced, processed, or packaged. This includes proximity to loading hatches or filing and unloading devices, fragile equipment, pipes, and glands on pumps and guides that are not adequately sealed. A flammable concentration is likely to occur during regular use.
Ignition sources that occur during regular, trouble-free operations and those that usually happen during malfunctions must be reliably prevented. The chapter “Electrical equipment for use in hazardous areas” describes the individual types of protection. According to Directive 2014/34/EU, Zone 1 equipment must meet the requirements of category 2G.

Zone 2
A zone in which an explosive atmosphere consisting of a mixture of air with inflammable substances in the form of gases, vapors, or mists is unlikely to occur during regular operation and, if it does happen, will persist for only a short period (EN 60079-10-1).
Zone 2 includes areas around Zones 0 and 1 and areas around flanged connections on pipes in enclosed spaces. In addition, it has locations in which, due to natural or forced ventilation, the lower explosive limit is reached only in exceptional cases, for example, in the environment of outdoor installations. In Zone 2, inflammable or combustible substances are produced or stored. The probability of an explosive concentration occurring is rare, and if it happens, it only lasts for a short time.
During regular, uninterrupted operation, ignition sources must be reliably prevented. According to Directive 2014/34/EU, equipment for Zone 2 must meet the requirements of category 3G. In addition, of course, any equipment that meets the requirements for equipment for use in Zones 0 and 1 are allowed.