Two Directives basically govern the explosion protection of machinery and plants within the European member states.

• • Directive 94/9/EC of the European Parliament and of the Council of 23 March 1994
• • Directive 1999/92/EC of the European Parliament and of the Council of 16 December 1999

Both Directives are also called the ATEX Directives (ATEX= Atmosphère Explosible). Whereas the “Manufacturer’s Directive” 94/9/EC lays down the essential requirements for improving the safety and health protection of workers potentially at risk from explosive atmospheres, the industrial safety regulation or Operator’s Directive 1999/92/EC divides the equipment and protective systems which it covers into equipment groups and categories; this Directive provides for a classification by the employer of the places where explosive atmospheres may occur in terms of zones and determines which equipment groups and categories should be used in each zone.

In Zones 0, 1, 20 and 21, only electrical equipment with an approval in the form of an EC-type examination certificate may be used; in Zone 0 however only those products that are explicitly approved for this zone. For electrical equipment intended for use in Zones 2 and 22, compliance with all the essential safety requirements of Directive 94/9/EC as well as a written declaration of conformity from the manufacturer is required.

As one of the largest industrial switchgear manufacturers in the world, the Schmersal Group offers a comprehensive range of safety devices for any application in Zones 2 and 22: from non-contact position switches (magnetic switches) up to safety switches with and without interlocking device for the protection of man.

Design and mode of operation:

Because of their low self-heating features, magnetic switches are particularly suitable for use at high ambient temperatures, as they never reach the ignition temperature of the gas or the dust, not even under live conditions.

The standardised switches of the series 235 and 335 with metal enclosure are particularly suitable for heavy-duty positioning applications of parts or machine axes. The large variety of actuating heads provides for a flexible application.

The Schmersal Group can even offer a comprehensive programme of safety switches and solenoid interlocks of type 2 (with separate actuator) to protect operators against hazardous machine movements in potentially explosive atmospheres. The large variety of useful accessories allows for a flexible application of these switches under all circumstances.