Standards and certification for hazardous area instrumentation. June 2015



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4. ATEX
4.1 Introduction
There are two ATmosphere EXplosive Directives [ATEX] in use at the present time. The directive which covers the marketing and manufacture of equipment for use in hazardous atmospheres is 94/9/EC generally referred to as the 'Apparatus Directive'. The other directive, 1999/92/EC is intended to ensure at least the minimum level of protection for workers in industries using hazardous materials. It is generally known as the 'user directive'.

4.2 User Directive 1999/92/EC
This 'worker protection' directive can be summarised as requiring a detailed, well documented risk analysis of the installation. Defining the acceptable risk is a very difficult task. The usual approach is to use equipment covered by appropriate Documents of Conformity, which is installed and maintained as required by the EN codes of practice [EN 60079-14, and -17] so as to achieve an acceptable solution. Theoretically a risk analysis can be used to circumvent the use of certified apparatus but this would require a very detailed comprehensive knowledge of all the relevant factors which is not usually available.

Consequently this option is not often used but can sometimes be used to justify the continued use of old equipment or installations. All European legislation has to be enacted in each country. Within the United Kingdom this Directive became law as part of the 'Dangerous Substances and Explosive Atmospheres Regulations' [DSEAR]. These regulations also include the requirements of the 'Chemical Agents Directive' [CAD], This arrangement can be slightly confusing but is a convenient arrangement since the requirements overlap.

Compliance with these regulations is the responsibility of the end-user. Some notified bodies do offer to carry out investigations and do inspections. These reports can be used to support the safety documentation but the responsibility still rests with the end-user.

4.3 Apparatus Directives 94/9/EC and 2014/34/EU
The directive which covers the design and marketing of equipment for use in hazardous areas is currently the 94/9/EC directive. It will be replaced on April 20th 2016 by the recently created directive 2014/34/EU. Fortunately as far as the supply and use of apparatus is concerned, the continued use and supply of equipment which is already certified will be permitted. New equipment or equipment being significantly modified will be certified to the new directive from that date. It will be necessary to issue revised Documents of Conformity [D of C] for existing equipment from the changeover date. The new Directive does slightly tighten the requirements for Notified Bodies and it will be interesting to see if there is a flood of new certificates on the day after the Notified Bodies have their ratification renewed.

The ATEX certificate is used as evidence of compliance with the requirement of minimising the risk of an explosion and authorises the use of the distinctive hexagon Ex mark. Usually ATEX certificates are based on the CENELEC standards [EN 60079-x Series] but theoretically can be issued based on the 'essential safety requirements' of the Directive, without reference to the detailed requirements of any standard. However this approach is rarely used. There are requirements for the manufacturer to have adequate quality control systems [which are subject to surveillance] so as to ensure that the product produced complies with the certification.

The directive only requires Category 1 and 2 equipment [usually interpreted as equipment for use in Zone 0 and 1] to be certified by a Notified Body. Category 3 [Zone 2] equipment can be 'certified' by the manufacturer but this is not always acceptable to the end-user and consequently most Notified Bodies do issue 'certificates' for Category 3 equipment. There is no shortage of Notified Bodies, for example the UK has eight which contrasts with one prior to ATEX.

The ATEX certificate is evidence of compliance with minimising the explosion risk but the legal requirement and the CE marking requires compliance with all relevant directives. This is recorded on the Document of Conformity [D of C] which lists the relevant directives and the method of compliance. The directives which are usually quoted for instrumentation are the ATEX Directive, the low voltage directive [LVD] and the radio frequency interference directive {RFID}. Other directives such as the machinery directive are applicable to some equipment.

The D of C is the responsibility of the organisation placing the equipment on the market. Frequently hazardous area equipment may also be used for non-hazardous applications and the D of C should take into account this possibility.

NOTE: All three directives usually quoted on the D of C have been updated and the common changeover date is 20th April 2016. The ATEX Directive 94/9/EC becomes 2014/34/EU, the EMC Directive2004/108/EC becomes 2014/30/EU and the LVD Directive 2006/95/EC becomes 2014/35/EU. The new directives do not require changes in the fundamental requirements hence re-certification will not be required, however the D of C will need to be modified.

4.4 ATEX Countries of use

EU member countries

There are a large number of countries where it is a legal requirement to comply with the ATEX Directive. The 28 states of the European Union [EU] [no longer the European Community] together with the three states which are members of the European Free Trade Area [EFTA] [Iceland, Liechtenstein and Norway] form the core of the common market.

There are a variety of customs agreements with Monaco, San Marino, Andorra and Turkey. Switzerland has 'an enhanced Mutual Recognition Agreement' with the EU. In addition a number of territories with ex-colonial attachments are also involved. These are French Guyana, Guadeloupe, Azores, Madeira, Canary Islands, Reunion, Saint-Barthelemy and Saint-Martin. The combination of these countries forms a large market.

There are some marginally surprising exceptions to this combination and in these territories ATEX is not a legal requirement. These include the Cayman Islands, Falkland Islands, Antarctic Territories, Bermuda, Faroe Islands, Greenland and Gibraltar. All of these have European connections but are not included.

In these and some other countries end-users specify ATEX certified equipment as a guarantee of quality. This is common practice in the Middle East, some Asiatic countries and for some marine applications. Possibly the trend is to specify IECEx equipment in preference to ATEX but the additional commitments of the D of C still influence some end-users. Offering both forms of certification is the option adopted by most European manufacturers.


 
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