Classifying hazardous areas into zones

When the ATEX directive is applicable, we will determine the ATEX zoning for you. Or you carry it out yourself with the help of our ATEX training. The different zones of explosion safety of gas or vapor are: ATEX Zone 2, ATEX zone 1 and ATEX Zone 0. For dust explosion it is ATEX Zone 22, ATEX zone 21 and ATEX zone 20. The results are clearly summarized in a zone classification and ATEX zones are indicated in the accompanying zone drawing.
For drafting the zones we use the Dutch Practice Guideline 7910-1 and 2 respectively for gas and dust zoning. Which lead to the following: indication of zone 0, 1, or 2, for gas and zone 20, 21 or 22 for dust, after which the dimensions are determined on the basis of calculations, tables or practice inspection under the locally prevailing ventilation conditions.
 

Explosion properties of all used substances
Then the explosion properties of the substances used are listed, such as the Kst, the flash point, the minimum ignition energy or the maximum permissible surface temperature. All results are clearly summarized in the reporting format and provide the foundation for drawing the zones in the zoning plan.

ATEX zone 2 en ATEX zone 22 for low risk locations during normal operation
ATEX zone 2 applies for a situation where the risk of a gas explosive atmosphere during normal operation is low, and the explosive atmosphere consists only rarely and for short duration. According NPR7910 for less than 0.1% of the operating time. ATEX Zone 22 applies for a dust explosive atmosphere under the same circumstances. 

ATEX zone 1 en ATEX zone 21 for significant risk locations
ATEX Zone 1 applies for circumstances in which the probability of an explosive gas atmosphere is significant. ATEX Zone 22 applies for a dust explosive atmosphere under the same circumstances. Between approximately 0,1% to 10% of the operating time.

ATEX zone 0 en ATEX zone 20 for locations with continuously or long periods of risk
In ATEX zone 0 and ATEX zone 20 is a gas or dust explosive atmosphere present continuously or for long periods, more than 10% of the operating time.

The zoning plan gives a clear description
The figure below shows different ATEX zones in a zoning plan.

 

atex ex zone indeling

 

atex zonering tekening

 

 

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