he ATEX directive 99/92/EC distinguishes between two types of explosive atmospheres: gas and dust Areas subjected to these two kinds of explosive atmospheres are each divided into three zones The zone’s characteristics are identical for gas and dust, but their numbering is different Zones 0, 1, 2 refer to gas and zones 20, 21, 22 refer to dust
Zone 0 / 20: Constant danger
Permanent presence of explosive gasses or com- bustible dust Minimum category 1 equipment
Zone 1 / 21: Potential danger
Occasional presence of explosive gasses or com- bustible dust during normal duty Minimum cat- egory 2 equipment
Zone 2 / 22: Minor danger
Presence of explosive gasses or combustible dust not likely to occur or only for a shorter period of time Minimum category 3 equipment
Grundfos manufactures pumps, with motors in both category 2 and category 3 The illustration on your right shows the division of an area into zones with different levels of danger of explo- sion For each of the three zones it is only a cer- tain category of equipment – in this case motors – that can be used due to danger of explosion
The owner of the equipment is responsible for defining whether an area is to be considered haz- ardous within the regulations stated in the ATEX directive However, if the user has any doubts about the definition of hazardous areas, he has to contact the proper authorities for advice
In Denmark the proper authority is the local Emergency Management Agency
The link between zones and equipment categories, is a minimum requirement If the national rules are more strict, they are the ones to follow
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