Comment

1 November 1999

Without ATEX, you'll have European safety problems

By Sean Clarke

In Europe, electrical and mechanical equipment or protective systems must meet the ATEX 100a directive.

In Europe, your electrical and mechanical equipment or protective systems must meet the ATEX 100a directive to be used in potentially explosive atmospheres containing flammable gases, vapors, mists, or dusts, so it is imperative that you know what you have to do to meet this directive.

Compliance for one of the European Communities' New Approach directives-the term derives from "ATmosphères EXplosible"-began voluntarily on 1 March 1996 and becomes mandatory after 1 July 2003. The directive covers any item that contains or constitutes a potential ignition source and requires special measures to be incorporated in its design and/or installation to prevent the ignition source from initiating an explosion.

Among the regulated equipment are electric motors, compressors, diesel engines, lighting fittings, control and communication devices, monitoring and detection equipment, and other types not previously covered. Also included are safety or control devices that are installed outside hazardous areas but have an explosion-protection function, such as flame arrestors, quenching systems, pressure-relief panels, and fast-acting shutoff valves.

Equipment categorized, marked

Marking requirements for ATEX certification now include equipment categories that designate the type of potentially explosive atmosphere. Through group I (typically coal mining) and group II (surface industries) equipment categories, ATEX expanded hazardous locations zones from existing zones 0, 1, and 2 for gases, vapors, and mists to include zones 20, 21, and 22 for dusts (see May 1999 InTech, page 122).

Manufacturers must use a European notified body or others to mark equipment for use in zones 0 and 1, where hazards may be continuously or mostly present. Some main notified bodies are SCS and BASEEFA (U.K.), PTB (Germany), KEMA (Netherlands), LCIE (France), DEMCO (Denmark), and TUV Rhineland (Austria). However, manufacturers can self-certify equipment for use in zone 2, where hazards are infrequent.

After 1 July 2003, the directive allows manufacturers to mark compliant equipment with the Distinctive (European) Community Mark Ex, which ensures equipment acceptance in European Union (EU) member states. Products covered must also have the legally required Conformité Européen (or CE) marking, which also facilitates the free movement of products within the EU.

Manufacturers affix the Ex mark to products. However, for products manufactured outside the EU, manufacturers' legally appointed EU representatives may affix the mark. Even so, manufacturers must comply with other applicable directives.

Demonstrated compliance equals certification

Certification means manufacturers must demonstrate equipment compliance with essential requirements-common, equipment, and protective systems-of the directive's Annex II.

In most cases, for example, manufacturers certify equipment against constructional design and test requirements of the latest applicable European harmonized standards. The Comité Européen de Normalisation Electrotechnique (CENELEC, the European Committee for Electrotechnical Standardization) significantly updated and reissued these standards over the past four years. Also, the Comité Européen de Normalisation (CEN, the European Committee for Standardization) recently published new provisional standards for mechanical equipment.

Because changes and additional directive requirements mean many manufacturers will retest and possibly redesign some equipment, it is important to determine whether equipment has the most up-to-date marking. For testing, extremely long lead times may occur because all existing equipment not currently ATEX certified needs to be recertified before the 2003 deadline, if manufacturers wish to continue selling equipment in Europe.

Zone 2 requirements changed

One example of legislative and technical changes is the new zone 2 equipment requirements.

Prior to ATEX, third-party test houses gave the zone 2 certification, though usually it was only a national certificate. That, however, did not entitle equipment to carry the distinctive Ex mark. Problems arose because many European countries do not accept other countries' national certificates; the new directive solves this problem.

Known as type "n" protection and for use only with the new directive, CENELEC's European harmonized standard for zone 2 equipment is Européen Normative or EuroNorm 50021:1999. Through it, most previously certified type-n equipment will need retesting and possible redesign. Some equipment still fails to comply with the new requirements; an example is with new conditioning requirements for plastic materials, for which thermal conditioning is required for two weeks before materials are used.

The other major change under the ATEX directive is that the Ex mark can be affixed to zone 2 equipment without use of a notified body-something not previously possible. This change allows manufacturers to self-certify equipment or use third-party consultants.

Above all, through ATEX 100a, users now know which standards that equipment used in potentially explosive atmospheres in their workspaces must meet. IT

Behind the byline

Sean Clarke, IEng, MAPM, MIIE, is an ATEX consultant with Epsilon Technical Services Ltd., Drury Lane, Drury, Buckley, U.K. (www.epsilon-ltd.com).