It's been 2 years since the release of IEC 60079-7, 2015 edition. There were quite extensive changes in terms of the marking for related apparatus. Nowadays we see more and more products come with new IECEx certificate and markings under 2015 edition. In this article, I'd like to talk about what's new in it.
Combine two standards into one
This is the most obvious change in this edition, 2015 edition is not only a simple revision for former 2006 edition. It also has IEC 60079-15, 2010 edition combine under one roof.
Ex nA (Non-sparking) seems to be a different protection technology from Ex e (increased safety). However, they are actually based on the same concept: low surface temperature and sparks free. The difference is Ex e (increase safety) also require integrity under fault condition within a given time, so that protection relay can act on the fault.
In other words, Ex e is a higher level Ex nA design which takes fault condition into consideration. This makes the changes in IEC 60079-7, 2015 edition fairly logical as the standard can be streamlined and refined for a common concept. This is an end user friendly change.
Level of protection is shown in new marking
Under IEC 60079-7, 2015 edition, former Ex e is changed into Ex eb; former Ex nA is changed to Ex ec. Calling both of them can give people the impression that they are under same design concept. "b" and "c" here are showing their suitability to different Zones. "b" is suitable for Zone 1 and Zone 2, "c" is suitable for zone 2 only. "a" is missing here as Ex e is not suitable for Zone 0.
This change is in-line with revision of IEC 60079-31 earlier in 2013. Protection type Ex t also uses "a", "b" and "c" to represent the suitability for different zoning.
Again, this is an user friendly move as well because information in new marking is clearer than before: what's the protection, which are the zones this product can go to. I think we will see new standards for other protection type such as Ex d, Ex p, etc. will follow this to make the life of people working in chemical, oil and gas sector easier.
No major changes to most of apparatus covered
Requirements for most of the apparatus covered by IEC60079-7, 2015 edition aren't changed from previous edition. Therefore, for most of the Ex nA certified products, they will come as they used to be, with new packing. Excuse me, with new marking. : )
Above are personal opinions regarding the changes in IEC 60079-7, 2015 edition; comments are welcomed if there is any. Considering that I'm working for the industry covered by part of the entire standard, I may not be able to give more insights for certain products. I shall be able to discuss more about the electrical motor if someone is interested about this aspect.
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