ATEX directive

ATEX is a widely used synonym for the ATEX guidelines of the European Union. The term ATEX is derived from the French abbreviation for ATmosphère EXplosibles. The directive currently comprises two directives in the field of explosion protection, namely the ATEX Directive 94/9/EC and the ATEX Workplace Directive 1999/92/EC.

Understanding the ATEX directives

The European Union ( EU) and its predecessor organizations (EC and EEC) have now brought numerous resolutions on the harmonization of the European market on the way. The main task is to ensure the free, unhindered movement of goods within the EU. To this end, numerous unharmonisierte national rules were unified and summarized and then transferred to European standards. The ATEX guideline is such a European Directive and dates from 1994. It covers equipment and protective systems, which need to be used in hazardous areas.

The ATEX guidelines of the Directorate-General for Enterprise and Industry of the European Commission in cooperation with Member States, the European industry, European standardization bodies (CEN, CENELEC) and the so-called notified bodies ( eg in Germany: BAM, PTB, ZELMEx or different TÜV) elaborated.

The ATEX Directives 94/9/EC and 1999/92 are addressed to the EC Member States. They are therefore obliged to implement in their national legislation at least as defined in the Directive standards into national law.

ATEX Directive 94/9/EC

The ATEX Directive 94/9/EC ( also unofficially known as " ATEX 95 " means, for the relevant Article 95 of the EC Treaty on the free movement of goods) of the European Parliament and of the Council on the approximation of the laws of the Member States concerning equipment and protective systems intended for Use in Potentially Explosive Atmospheres sets the rules for the marketing of products that are used in hazardous areas. With this Directive for the first time the non-electrical appliances were included. Thus, for example, rotating couplings lead by inadmissible high heating to ignition.

Main purpose of the Directive is to protect people who work in hazardous areas or who may be affected by explosions. The Directive contains in Annex II, the essential health and safety requirements that must be observed by the manufacturer and must be verified by appropriate conformity assessment procedures. In addition, the elimination of technical barriers to trade is an important recital.

Since 30 June 2003, only such devices, components and protective systems for use in hazardous areas should be placed on the market that meet the ATEX Directive 94/9/EC. This European Directive was transposed in Germany by the explosion protection regulations ( 11 ProdSV ) into national law.

Explanation of terms

  • Devices and Components "Device " means machines, apparatus, fixed or mobile devices, control components and instrumentation thereof and detection or prevention systems which, separately or jointly, for the generation, transfer, storage, measurement, control and conversion of energy and the processing of material are intended and have their own potential sources of ignition and capable of causing an explosion.
  • As the " components " refer to those components that are required for the safe functioning of equipment and protective systems but with no autonomous function.

Device groups

G = gas, D = dust

Devices of a particular category may only be used for specific zones, for example, Category 2 equipment only for Zone 1, 2 ( for gases or vapors ) or for zones 21, 22 ( for dust).

  • Explosion group

Gases and vapors are classified due to their special ignitability in three explosion groups (IIA, IIB and IIC). The danger increases from explosion group IIA to IIC. ( The higher explosion group IIC example includes the respective lower groups IIB and IIA. )

Temperature classes

Temperature classes for gases (T6 => T1)

Temperature data dusts ( for example: 120 ° C)

In addition, temperatures are generally between electrical and non - electrical equipment noted differently.

To facilitate the configuration of a plant, 6 temperature classes (T1 to T6) have been set for the permissible surface temperatures. This temperature classes can be assigned to certain combustible gases and vapors due to the corresponding ignition temperatures. For the temperature classes the following maximum allowable surface temperatures on the devices are:

Resources that a higher temperature class eg T6 ( max. heating of the device to 85 ° C) are permitted, are also suitable for the worse temperature classes T1 to T5.

Temperature Information Dusts: The classification of dusts into temperature classes do not exist, because for dusts a safe distance between the surface temperature and the ignition temperature is observed. For dusts the maximum permissible surface temperature (eg 300 ° C) of the equipment specified instead of the temperature class.

Compared to electrical devices that generate "non- electric " products such as Couplings in the operation itself has no major temperature but transfer the process temperature. Therefore often [ TX ] is used here.

ATEX Workplace Directive 1999/92/EC

The ATEX Workplace Directive 1999/92/EC (also unofficially referred to as " ATEX 137 ", because of the relevant Article 137 of the EC Treaty ) defines the minimum requirements for improving the safety and health protection of workers potentially at risk from explosive atmospheres. This policy was implemented in 2002 as part of the operating safety regulations in German, or explosive atmospheres by Regulation ( VEXAT ) into Austrian law. This Directive lays down basic safety requirements which implement the operator / employer. These include:

  • Preventing or mitigating the formation of explosive atmospheres ( primary explosion protection)
  • Avoid effective ignition ( secondary explosion protection)
  • Restriction of the impact of a possible explosion to an acceptable level (tertiary or constructive explosion protection)

The employer has as part of its risk assessment to create an explosion protection document and classify areas where hazardous explosive atmosphere in zones.