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European harmony at last

01 November 2008

After an inordinate delay, a correct and up-to-date list of harmonised standards for the ATEX Directive have been published in the Official Journal of the European Union. A delighted Ron Sinclair celebrates the consolidation of various hazardous area standards

Ron Sinclair
Ron Sinclair

It is about two years since the last time the Cenelec standards for electrical equipment were correctly listed, although CEN have managed to keep their half of the list up-to-date by several intermediate issues over that period. There was one intermediate issue which listed some additional Cenelec standards in March this year, but many standards which should have been in the list were omitted and some of the ‘cessation of conformity’ information was incorrectly given.

However, although the OJEC list, published during August is now correct, this does not help those wanting to interface correctly with both ATEX and IECEx. The table provides an enhanced list of the more common electrical standards in this field, together with the relevant dates for use for both ATEX (94/9/EC) and IECEx and this is reproduced here.

Now that the EN 50014 series of standards has effectively gone, we are in a position where the technical requirements for ATEX and IECEx are virtually identical, and it makes sense for nearly all manufacturers to get dual IECEx/ATEX certification for their products: ATEX to meet the legal requirements for sale in Europe, and IECEx to demonstrate the conformity of the product within a proper product certification scheme and to assist sales outside Europe.

There is a minor difficulty is the General Requirements document, however. IEC 60079-0 Edition 5 was published in 2007, but we are still waiting for the EN version to be available. Currently EN 60079-0:2006 is correctly shown as harmonised. This is the 2004 Edition 4 of IEC 60079-0 with a number of minor (non-technical) amendments.

It is possible that the EN version of the latest edition will also be dated two years behind its IEC base as we are awaiting permission from Cenelec headquarters to agree a particular format for the European foreword to enable a clear listing of the major differences between the editions. It was agreed in the TC31 meetings in Prague last autumn that such a list was necessary to fulfil the obligations of the standards-making bodies, under the preamble to Annex II of the directive.
Despite the differences between EN 60079-0:2006 and IEC 60079-0:2007, it will often be worthwhile to have the product assessed to the later standard, particularly to take advantage of the new marking arrangements which includes the Equipment Protection Levels (EPLs). This is particularly important where acceptance for both gas and dust hazards is required, as previously there has been much confusion on the way the two incompatible marking systems are combined.
There will also be a degree of future proofing in the documentation as the current 2006 EN version will cease to be harmonised three years after the new EN version is published.

EN 60079-25 – A special case
There was considerable debate as to whether the standard for intrinsically safe systems should be harmonised or not. The standard is essentially related to the design of an installation, rather than a manufactured product, and in that context its material is outside the scope of 94/9/EC, the ATEX Directive, because it is not normal for an identifiable discreet product to be certified to that standard.

However, there was an argument that, occasionally, a complete turnkey system is placed on the market – i.e. the complete system, including cabling, is sold as a single package. In this case, it was argued, the turnkey system came within the scope of the directive and therefore there was a case for harmonising the standard.

The important point to note is that the harmonisation of this standard does not affect any existing system certificates, and it is not the intention that any previous design work should be revisited. Most system certificates relate to products from more than one manufacturer, and it is clearly not appropriate for such a system design to be treated to all the conformity assessment processes of the directive. Therefore, unless you are selling a turnkey system, and elect to follow the full conformity assessment procedures, you can ignore the fact that this standard is harmonised.

Ron Sinclair is chairperson of BSI Committee GEL/31, which is responsible for the UK input to both European and International standards for Electrical Equipment for use in potentially explosive atmospheres. He is also chair of Cenelec TC31 and responsible for representing electrical standardisation interests at the European Commission’s ATEX Standing Committee. He makes a major input to BSI Committee FSH/23, which has responsibility for input to CEN for non-electrical equipment and protective systems.

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