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Sunday, April 30, 2017
The Automation Safety Community Forum.
Ex ia and IECEX Flameproof, ATEX Flameproof, CSA/US-Exp.
can we use IECEX Flameproof, ATEX Flameproof, or CSA/US-Exp device instead of Ex ia rated device for Zone 1?

WE requested supplier to supply Ex ia rated device for Zone 1 and he replied he can only supply IECEX Flameproof, ATEX Flameproof, CSA/US-Exp. With respect to the answer provided by supplier is it acceptable? Please help

By Bob Peterson on 4 August, 2016 - 6:03 pm

*WE requested supplier to supply Ex ia rated device for Zone 1 and he
replied he can only supply IECEX Flameproof, ATEX Flameproof, CSA/US-Exp. *

You want something intrinsically safe. They only have equipment that is flameproof or explosion proof. It might be that the level of power required to run whatever it is you want cannot be supplied using the power limits of intrinsically safe equipment.

*With respect to the answer provided by supplier is it acceptable? *

As I understand it, IEC standards don't allow for flameproof equipment to be used in zone one areas. The answer may be the correct answer, but it does not make the equipment suitable for your requirements. However, I would say it is the truth so the answer is what it is. The solution he is offering may not be acceptable. However, most times it is not that difficult to get the equipment out of a zone 1 area and into a zone 2 area where flameproof is an acceptable protection technique.

By gunawan556 on 5 August, 2016 - 4:09 am

There is flameproof rated device available for zone 1. But the type of protection which are suitable depends on condition such as operation behaviour, space limitation, temp class on site, budget, etc.

For example "operation behaviour", if you use Ex d rated device, you cannot open the enclosure/gland without checking if gas leak appears around equipment, while for Ex ia such check activity is not necessary. Cable removal is also somewhat more complex since the gland type for Ex d usually hard to remove.

"space limitation", Ex d sure are much bulky than Ex ia.

"temp class on site", Ex d protection are limiting temperature that may come out from the enclosure. If the temperature class on that site is lower than temperature class of Ex d enclosure, you shall not use such enclosure.

Regards,
Gunawan