ATEX Valve installation on gas line??

[SL1000]

Please can you oblige with guidance on a hazardous installtion I have come across. I will be consulting with various experts and manufacturers but just need a heads up so I can iron out what I need to know.

I've recently stopped a job until I can clear this up. A ball valve on a methane gas train was being used to control the flow of gas to a rotary kiln burner. A replacement valve (new butterfly) had been purchased to replace the existing valve. After consulting the drawings it is within the confines of a zone 2 area (as it was within 300mm of it's flange).

The actuator is rated at 24V and 4 amps but is NEMA 7 (what does this mean?). The signal is 4-20mA. My first question is shouldn't this actuator equipment be ATEX certified?

The valve body that the actuator is bolted to is quoted as a butterly suitable for use on natural gas. Again under ATEX shouldn't this be certified (my concern here is: is it possible for a potentially explosive concentration of gas to pass up the shaft past the valve packing and into the actuator under a seat failure) I'm not sure if I'm on the wrong horse here - does the fact that IF the actuator was approved to ATEX cover this? i.e. does the bfly valve, body and bareshaft arrangement need to be certified?

By the looks of it, it looks like 2 diffent products have been bolted/brought together by the 3rd party supplier.

Thanks in advance

 

[ab123456]

Everybody I have spoken to about ATEX seems to have a different opinion, here are my thoughts to add to the confusion.

If you are replacing/modifying an existing bit of kit destined for a hazardous area then it now has to be ATEX certified unless you are replacing it in the same location with an identical model already in your stores. I am unsure as to whether you are changing the actuator as well as the valve but even if the actuator is existing in a zone 2 area it should be at least EX certified though not neccesarily ATEX.

ATEX covers both electrical and non electrical equipment, I find ATEX certified electrical equipment relatively easy to get hold off as these companies have been producing EX certified equipment for years but I still speak to many equipment suppliers who have still not heard of atex and want to know why they are losing our business!!

New equipment has to be ATEX certified, risk assessments have to be performed on all existing equipment to idetify any ignition hazards before July 2006.

Hope that helps but fear I may just have added to the confusion!!

 

[ilan7]

Dear SL1000
Think you are a bit mixing between US and European standards. The NEMA 7 stamped on the actuator means:
"Indoor use in locations classified as Class I, Division 1, Groups A, B, C or D hazardous locations as defined in the National Electric Code (NFPA 70) (Commonly referred to as explosion-proof)." (Quoted from the UL site).
That's means the actuator enclosure is ok for your aplication (INDOOR). You still suppose to have certificate for the actuator fron an aproving agency. If you are in Europe, you need to have an ATEX certificate for the actuator and for the valves. If you are at the US you need to have an UL, FM, CSA or equivalent certificate. For other area, it depends on the country regulations.
The valve, as it controls flamable liquid / gas must have grounding wire to eliminate the option of haveng static charging build in an isolated part. Some other specs calls for Fire safe valve when blocking flamable gases.

 

[SL1000]

Thanks for the replies,
from what you have both added I take it then that the actuator although possibly physically suitable for the job it cannot be used in the UK without ATEX certification on a hazardous (zone 2) application. Also that even the butterfly valve that it modulates needs to be ATEX approved.

Do you know who I can contact for an ATEX approved valve solution?
The application does have other saftey valves associated with it - slam shut and fire valve etc.

 

[ilan7]

Stop at SIRA site

http://www.siraservices.com/media/contact/index_contact.html

think they will be able to help you solve this problem.
Cheer up ilan