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A busy Autumn

Author : Ron Sinclair

29 November 2010

October is when we usually cram in both the international IEC TC 31 meetings and the European Cenelec TC 31 meetings. This year was no exception, with just one week’s break between meeting in Seattle and meeting in Braunschweig.

Ron Sinclair
Ron Sinclair

By the time you read this, both will be fading in the memory, but there are a number of points worth recording.
About 3,000 delegates attended the Seattle meetings, with the TC 31 schedule, although just a small part of the whole event, being one of the busiest, spreading across two full weeks.
Things are moving apace in the development of the non-electrical standards in SC 31M, with a great willingness now evident to successfully complete the project of truly integrating the requirements within the ISO/IEC 80079 and IEC 60079 series of standards. The very first standard in this series, 80079-34, the dedicated quality system standard replacing both EN 13980 and IECEx OD005, should be published in the first half of 2011, with the public comment document for 80079-36, the first standard specifically for non-electrical equipment, becoming available at the same time.
60079-33, the new standard for Ex ‘s’ Special Protection, will also move to the public comment stage. This standard has been written particularly at the request of the IECEx Scheme to allow the possibility of some flexibility in certification of newer product developments at the international level. The intention is to mirror the possibility afforded under the ATEX Directive in Europe of working to first principles where the product cannot meet the requirements of an existing type of protection.
UK readers with long memories may recall that both encapsulation and flameproof breathing devices were covered under the Baseefa Ex ‘s’ standard SFA 3009, until requirements were developed at the international level. Unfortunately, in my opinion, it is being suggested by some of the European countries that this standard should not be adopted as an EN “as we don’t need it”, but I think it will prove a very useful methodology to demonstrate compliance with the Essential Health and Safety Requirements for ATEX.
Manufacturers of Ex ‘ta’ dust protected equipment for use in Zone 20 will be pleased to know that preliminary discussion on the next edition of 60079-31 could see the 500mm layer depth test reduced to 200mm, based on experimental research done by Baseefa. This will reduce the amount of dust required for the test by more than a factor of 10 and make the whole thing more practicable.
The TC 31 committee has become concerned that many of the concept standards place requirements on cells and batteries in different ways. Consequently a horizontal working group is being set up to monitor battery requirements in all the standards. If anyone has a personal interest in this area of work and is prepared to join the group, please get in touch.
In Europe our discussions were once again dominated by the thorny subject of “State of the Art”. However, we now seem to be getting to the bottom of the divergent opinions.
One of the principal difficulties is the way that Germany has implemented the ATEX User Directive 1999/92/EC. In the UK, HSE implemented the directive by a fairly simple bit of legislation, DSEAR, supplemented by Approved Codes of Practice. However, in Germany, the law is very prescriptive and some German users are very concerned, despite statements to the contrary by the European Commission, that their inspecting authorities will start to impose “State of the Art” on existing installations.
It is absolutely clear from the ATEX Guidelines document on the European Commission website that this was never the intention, but there seems to be genuine concern.
Purchasers of the latest 2010 edition of BS EN 60079-15 will have read in the BSI foreword that BSI committee GEL/31 was unable to confirm that there had been proper consultation of the “State of the Art” table in Annex ZY, and that it is intended that a corrigendum should be published. The amended table was developed at the October meetings and should make more sense than the current published version.
Please make sure that you get this when it is eventually published. This document is being put through the system for voting by National Committees in two different ways; firstly as a model for the style of such documents and secondly for the actual statements on “State of the Art” for this particular standard.
Whereas in Seattle the IEC community had fought shy of starting work to assign probability levels for ignition to the conventional types of protection, the decision in Braunschweig was that initial work should start to see if this is feasible. This had been instigated by the UK on the basis that SILs relating to IEC 61508 are becoming more and more part of the safety basis for Ex Equipment.
If the initial safety levels are not known on a quantitative basis (at least pragmatically) it is very difficult to work with the Safety Integrity of a control system in a coherent fashion. Watch this space.


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