Conformity Magazine - April 2008 - (Page 14)

The ATEX Directives The EU’s ATEX product directive (94/9/EC) for equipment used in hazardous locations became mandatory in July 2003. It is a CE marking directive, and is sometimes referred to as the “ATEX Product Directive” or “ATEX 100.” The directive covers the different requirements applicable to mining (group I) and surface (group II) applications, and applies to electrical and mechanical equipment, including electric motors, compressors, diesel engines, lighting fittings, control and communications devices, and monitoring and detection equipment. For most categories, mandatory third party certification by an ATEX Notified Body is required. ATEX Notified Bodies are European organisations accredited by their national governments as competent to conduct ATEX assessments and issue Notified Body certificates. A second ATEX directive (1999/92/EC) became mandatory in July 2006. It applies to the locations themselves and contains rules for the persons responsible for the location. This is sometimes referred to as the “ATEX Use Directive” or “ATEX 137.” As it is comparatively new, its impact is still reverberating through many parts of the European manufacturing industry. The two directives are linked because the ATEX Use Directive not only defines the extent of the hazardous area (the zone), but also specifies the categories of ATEX equipment (according to 94/9/EC) that are permitted to be used in that zone. So it is important for manufacturers of equipment to understand both directives. Applying the Directives In order to provide consistency in the application of ATEX rules, the European Commission has a Standing Committee, comprising members from all EU countries, that is responsible for ATEX policy. In addition, the Notified Bodies operate a forum for discussing and addressing technical issues affecting compliance, known as the ExNB Group. The ExNB Group is independent, but has links to the Standing Committee. Area classification Surface applications Details of the output of the Standing Committee and the ExNB Group can be found on the EU Commission’s Europa website (http://ec.europa.eu/enterprise/atex/index_en.htm). In May 2007, the Commission produced a guidance document on the application of the ATEX product directive. This is also available for free download from the Europa website. Hazardous Zones A hazardous zone is determined according to the rules set out in EN 60079-10. ATEX recognizes three classes of zone for both gas and dust environments. Table 1 compares the ATEX and U.S. National Electrical Code 500 and 505 classifications. It is worth noting that all of these classification systems subdivide the gas groups and temperature classes within the gas classification. The U.S. and ATEX systems differ in that the ATEX system does not have dust groups (defining them instead by temperature classification alone), and the U.S. system defines its hazardous locations into two rather than three types (although there is some equivalence between the types). ATEX Equipment Categories For each zone classified, the level of protection required for equipment to be used in that zone is defined. Whereas the U.S. systems directly link equipment to location, the ATEX system divides equipment into three categories (1, 2 and 3), and only permits certain categories of equipment to be used in a given zone. Each ATEX category is further sub-divided into either gas (G) or dust (D) hazard protection (e.g., 2G, 1D). A risk assessment approach for the acceptance of Ex equipment has been introduced by the IECEx within installation standard IEC 60079-14. This is an alternative method to the current prescriptive and relatively inflexible approach, which links equipment directly to zones within IECEx standards. Hence, the most recent IEC 60079-0 standard (5th edition, 2007) adopts the concept of equipment protection levels (EPL). These apply to gases (Ga, Gb and Gc) US NEC Article 500 505 Dust See note Class II, Div 1 Class II, Div 2 Gas Class I, Zone 0 Class I, Zone 1 Class I, Zone 2 Dust Zone 20 Zone 21 Permitted equipment Gas - 1G Dust - 1D Gas See note EU ATEX Gas Flammable atmosphere is present continuously or for long period of time (often quantified as >1000hrs/yr) Flammable atmosphere is likely to occur during normal operation (often quantified as >10 and <1000hrs/yr) Zone 0 Zone 1 Gas - 1G, 2G Class I, Dust - 1D, Div 1 2D Gas - 1G, 2G, 3G Dust - 1D, 2D, 3D Class I, Div 2 Flammable atmosphere is not likely to occur in normal Zone 2 operation (i.e. only rarely) and, if it occurs, will exist for only a short time (often quantified as <10hrs/yr) Zone 22 Note: There is no direct equivalent of a zone 0 or 20 in the US NEC Article 500 system. Table 1: ATEX zoning and categories 1 Conformity April 2008 http://ec.europa.eu/enterprise/atex/index_en.htm

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Conformity Magazine - April 2008 NewsBreaks Editor’s Note Mandatory Analog Cellular Service Ends FCC Releases Quarterly Reports on Consumer Inquiries and Complaints New Standards List Released for The EU’s Low Voltage Directive FDA Issues Notification on Unretrieved Device Fragments FDA Offers Guidance on Waivers for In-Vitro Diagnostic Devices ESD Open Forum Emerging Issues in Standards Challenges in Testing Design Fundamentals Focus on... New Products Product Reviews Premarket Approval Application Guidance Issued by FDA New Jersey Enacts Electronic Waste Recycling Regulations A New U.S. Standard for Workstation and Computer Design Might the CPSC Hold Retailers Accountable for Safe Products? CPSC Loses “Sole Toy Tester” CPSC Actions in the News IEC Standards Update UL Standards Update Telcordia Standards Update From Our “You Can’t Make This Stuff Up” Department Looking Back: Items from Past Issues of Conformity Advertisers

Conformity Magazine - April 2008

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