IECEx and ATEX Ex approvals For dust-approved operation, equipment used in explosion protected (Ex) industries must be certified in accordance with the IECEx international certification system or the EU directive 94/9/EC, also called the ATEX directive. The IECEx and ATEX directives describe safety requirements for applications and products in explosive atmospheres and account for both mechanical and electrical sources of ignition in these areas. LINAK offers products that have been tested and certified for electrical operation in dust explosive atmospheres by the notified body TÜV Nord. Our actuators displayed in this folder have all been certified according to both IECEx standards and the ATEX 2D and 3D categories. This means that they can be used in Ex zones 21 and 22 - see the illustration below. Furthermore, the actuators have been approved for non-mining applications, and for the temperature range of -25°C to +65°C. When can a dust explosion occur? Dust explosions require the presence of a combustible substance, oxygen and an ignition source. Both electrically and mechanically generated sparks, arcs and open flames are ignition sources. Mechanically generated sparks are far the most frequent cause of dust explosions. Dust explosive atmospheres may occur in: • Power stations • Grain mills and grinders • Chemical factories • Paint factories • Cement plants • Animal feeding industries • Harbour installations • Woodworking machines • Ventilation systems • Other dusty areas 20 21 22 Category 1 equipment Category 2 equipment Category 3 equipment Dust occurs continuously Zone 20 is a place in which an explosive atmosphere in the form of a cloud of combustible dust in the air is present continuously, for long periods or frequently. This would typically include the inside of containers or pipelines and enclosed conveying equipment. Dust occurs occasionally Zone 21 is a place in which an explosive atmosphere in the form of a cloud of combustible dust in the air is likely to occur in normal operation occasionally, for example when discharging and filling equipment. Dust occurs in short periods Zone 22 is a place in which an explosive atmosphere in the form of a cloud of combustible dust in the air is not likely to occur in normal operation but – if it does occur – it will persist for a short period only. Areas in which dust escapes from leaks and forms dust deposits are included in this category. 2
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