Intrinsically Safe With ATEX

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 Who or What is ATEX, and What Does it Have to do With Me?

Perceptive observers may have recently noted a spate of new products touting ATEX compliance. The first question for most is: What is ATEX? And the second: What affect will this have on process plants?

The ATEX ("Atmosph‚¨res Explosibles," French for explosive atmospheres) Directive 94/9/EC is a directive adopted by the European Union (EU) to facilitate free trade in the region by aligning the technical and legal requirements in the member states for products intended for use in potentially explosive atmospheres.

The directive covers electrical equipment, mechanical equipment, and protective systems that may be used in potentially explosive atmospheres (flammable gases, vapors, or dusts.) The full text of the ATEX directive can be found at http://www.epsilon-ltd.com/full_atex_directive.htm.

From a manufacturer's point of view, products sold to EU member states must have a CE mark. For products that fall under the umbrella of ATEX, the CE mark can only be used if the products comply with the new ATEX directive. Compliance is voluntary until July 1, 2003 and mandatory thereafter.

From a North American end-user point of view, expect to see vendors mentioning ATEX compliance. Although North American process plants are not covered by EU regulations, standards bodies worldwide often try to harmonize regulations. This means that standards bodies in North America may adapt regulations similar to ATEX in the near future.

Items covered by ATEX include "any item which contains or constitutes a potential ignition source and which requires special measures to be incorporated in its design and/or its installation in order to prevent the ignition source from initiating an explosion in the surrounding atmosphere."

Also covered by ATEX are safety or control devices installed outside a hazardous area, but nevertheless incorporate an explosion-protection function. Protective systems are covered as well: these are technologies that prevent an explosion from spreading or causing collateral damage. Protective systems include flame arresters, quenching systems, pressure relief panels, and fast-acting shut-off valves.

Intrinsic safety is widely used in Europe as a means of installing equipment in hazardous areas, and ATEX deals extensively with intrinsic safety.

Intrinsic safety is a protection standard employed in potentially explosive atmospheres. Devices that are certified as intrinsically safe (IS) are designed to be unable to release sufficient energy, by either thermal or electrical means, to cause ignition of flammable material (gas, dust, particulates, etc.).

IS standards apply to all equipment that can create one or more of a range of defined potential explosion sources including electrical sparks, electrical arcs, flames, hot surfaces, static electricity, electromagnetic radiation, chemical reactions, mechanical impact, mechanical friction, compression ignition, acoustic energy, or ionizing radiation.

ATEX is a European standard developed in part by the International Electrotechnical Commission (IEC). IEC is responsible for setting international standards for electrical technology. Its technical committee TC31 deals with explosion protection for electrical apparatus. It has introduced a procedure, the IECEx Scheme, which is intended to become a globally recognized test and certification procedure for explosion protection.

In The United States, Factory Mutual Research, managed by Factory Mutual (FM) Global, is a not-for-profit scientific and testing organization that has tested and certified more than 40,000 products over the last 165 years. FM Research has set certification guidelines for equipment used in potentially explosive atmospheres.

The NFPA (National Fire Protection Association) 70, National Electrical Code, also known as the NEC, is the basis for all electrical codes in the United States. Classifications and related product markings for hazardous areas are covered in NEC 500 and 505. These are similar to, but not exactly the same as, those in ATEX.

OSHA (Occupational Safety & Health Administration of the U.S. Department of Labor) participates in the US-EU Cooperation on Workplace Safety & Health. This is a project of the U.S. Department of Labor, OSHA, and the EU European Agency for Health and Safety at Work. The goal is to promote sharing of information on current safety and health topics of common interest.

Intrinsic safety is covered under Regulations (Standards - 29 CFR) and Hazardous (classified) locations 1910.307 and 1926.407. OSHA references the NEC guidelines for determining the type and design of equipment and installations which will meet this requirement. There are no global IS standards or certifications.

Currently the ATEX standard affects only manufacturers who are selling product into the European Union (EU) that are intended for environments subject to explosion hazard. Considering the joint effort of OSHA and the EU, the long-term effect of ATEX may be a global standard to which all manufacturers would need to comply.

The July 1, 2003 deadline to meet the new ATEX regulations focused attention on the issue of providing intrinsically safe products in potentially dangerous environments. However, there has already been a great deal of attention placed on workplace safety by regulatory groups as well as manufacturers.

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