Flat out down under
Author : Ron Sinclair MBE
04 January 2012
The Melbourne International Convention and Exhibition Centre on the banks of the River Yarra proved an excellent venue for the series of TC 31 meetings held during the IEC General Meeting in October.
The Melbourne International Convention and Exhibition Centre on the banks of the River Yarra
Despite a number of us suffering the effects of jet lag (and some the vagaries of the Qantas industrial dispute), TC 31 had arranged 21 meetings over an 11-day period – and I managed to attend nine of them.
First off was WG22, where we took forward new texts for the revision of the standards for Ex o and Ex q, as well as initiating work on the next edition of the “Ex” content of the “IEV” – the repository of all definitions related to our work.
IEC 60079-7 is being extensively revised to incorporate many of the requirements currently in IEC 60079-15. The original Ex e material will remain as Ex eb, while the Ex nA material from Part 15 will be introduced as Ex ec.
This is part of the exercise intended to provide all the different levels of protection of each type of protection in the same standard. This has already happened for encapsulated equipment, where Ex mc has joined Ex ma and Ex mb in IEC 60079-18, and for the low-energy equipment, where the previous ExnL equipment from Part 15 now needs to be considered as Ex ic in Part 11.
There were two separate but overlapping meetings on this subject: WG 27 dealt with rationalising the rotating machine requirements, while MT 60079-7 looked at the rest of the comments received on the initial draft document. It is proving difficult to amalgamate requirements which have originated in two different places, but the maintenance team is working hard to achieve it.
There were surprisingly few comments to be reviewed on the proposed Ex s standard, and this will now be released as an FDIS (Final Draft International Standard) for formal voting. In Europe, the plan is to release this as a Technical Report, rather than a European Standard, as it is more prescriptive than the ATEX Directive and potentially could cause legal problems. (By implication, the international community is seen as expressing concerns that the implementation of ATEX is not sufficiently rigorous.)
In MT 60079-26, we decided to proceed with a revision of the “Zone 0” standard, primarily to remove some of the anomalies left over from many of the requirements now appearing in IEC 60079-0. This has left some doubt as to whether or not all equipment intended for installation in Zone 0 needs to be certified to Part 26, as well as the basic concept standard. It will now be clear that only the special arrangements, including double protection, given in the document will require invocation of the standard.
The final meeting was the TC 31 plenary session over two days, where all the sub-committees, maintenance teams, project teams and working groups reported to the parent organisation.
We learned of the work going forward on:-
Gas/Dust Hybrid Mixtures
Equipment Process Sealing
Vacuum Cleaners
Extended Atmospheric Conditions
o Very low temperatures
o High atmospheric pressures
Application of IEC 60079-28 to LED Luminaires
Possibly of most significance to Europe is an agreement to adopt, at IEC level, a format similar to the Cenelec Annex ZY approach, to identify the significance of changes between successive editions of a standard.
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