Mülheim on the Ruhr, August 25, 2005. Another milestone for the Development Department at ms Neumann Elektronik GmbH: The PTB Braunschweig has classified the Series WFD-EX-2/4/6 and WFA-EX-2/4/6 intercom stations as Cat. II 2D certified.

The explosion-proof, Weatherproof Digital (WFD) Call Stations from ms Neumann Elektronik GmbH, classified as per ATEX (EC Directive 94/9/EC), allow direct intercom connections to other call stations, and PA loudspeaker announcements, to be made in potentially explosive environments. When the easy-to-use, robust double lever talk keys are pressed, they activate contactless optocouplers. The dust- and watertight, fiberglass-reinforced polyester enclosures make them ideal for use in aggressive, moist environments, and now, with the new classification, also in dusty environments, particularly in areas with concentrations of explosive gases and dust particles.

Explosions can always occur anywhere where flammable gases, vapors, liquids and also dust are produced, stored or transported, and where these, under certain conditions, can create an explosive mixture in combination with air. Potentially explosive dust particles are released by chemicals, wood, flour, metals, pharmaceuticals, animal feed and sugar, among others. The various areas are classified into different zones that are defined according to the "release from sources" concept. For dust particles, the zones 20 (continuously releasing source), 21 (primary releasing source) and 22 (secondary releasing source) are used.

Cat. II 2D Classification

Thanks to the new classification, the intercom systems can now be used in dusty environments, e.g., in chemical factories, animal feed factories, coal power plants, paint factories, grain mills, ship loading stations in harbors, underground mining operations, cement factories, etc. Particularly for these potentially explosive areas, very strict regulations apply with regard to the requirements placed on the instruments and devices that are allowed to be used in these areas. The devices are first classified into groups and categories, and are then classified into the corresponding hazardous zones where they may be used.

The Series WFD-EX-2/4/6 and WFA-EX-2/4/6 Call Stations now comply with the requirements for dust zones, and this was certified in the PTB test report of July 12, 2005. The use of innovative new rubber seals in the units has enabled the test certificate to be expanded to include compliance in these "dust" zones.

New Industrial Uses for the Intercom Systems

Detlev Hartwich, Product Manager for Industrial Applications, said, "This new certification allows us to enter entirely new areas for the use of our proven intercom systems. Particularly for uses in dusty and potentially explosive environments, there existed until now no other alternatives for reliable, safe communications. This certification has therefore met with very positive response from our customers."

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