ATEX certification/IP rating

[Fireal86]

Hi,
I'm currently pushing through atex certification an instrument comprising of an exd and exe enclosure, connected via exe/d trunking.

The exe enclosure has 2 bulkhead ss pneumatic compression fittings from a popular manufacturer that rhymes with gaugelock. The certification company has said that the two bulkhead fittings, because they're not ip rated, hinder the ip rating of the cabinet.

How do I get around this? Is it just a simple as installing ip/ Sealing washers? I see instrumentation with bulkhead fittings on ip rated equipment all the time but the ip rating is still maintained.

I'm UK based BTW.

Thanks

 

[Gr8blu]

Ex classification and IP designation are not cross-linked. They are separate considerations. It is entirely possible to have a Ex enclosure (which is designed to contain / limit the damage from an explosion) that has moisture inside (which means the IP rating is very low).

Which is your concern? The Ex e / Ex d designation? Or the Ingress Protection (IP) classification?

Converting energy to motion for more than half a century

 

[Fireal86]

hi,

my concern is both

they have said:

For Group II (explosive gas atmosphere) equipment, IP 54 or greater would be sufficient; and IP 64 or greater is sufficient for the Group III (explosive dust atmosphere) equipment.

so we need to maintain ip rating for specific gas groups.

they have come back with if i choose to install ip washers the enclosure will have to go through over a month of testing. which is highly frustrating as they have been dragging this on for nearly 2 years now.

thanks.

 

[Gr8blu]

IP 54 - dust protected (particulate up to 0.075 mm) and protected from splashing water.
IP 64 - dust tight and protected from splashing water.

I take it you know how these tests are performed? The "dust protected" test takes anywhere from 1 to 8 hours to complete. The splashing water test takes no more than 15 minutes (for a reasonably sized enclosure - may be more if the object is really large and/or the water "source" is relatively small).

It might be as simple as realizing that 60079-1:2014 (Ex d) is currently in effect (check the IEC standards store - they'll let you preview a part of the document that includes some interesting tidbits that directly impact your fitting decision). Note that an updated version is expected to be available in February 2025.

Similarly, 60079-7:2017 (Ex e) is the version in effect, with a notice that it will begin its next revision cycle in January 2025.

Converting energy to motion for more than half a century

 

[Fireal86]

Hi,

thanks for your reply.

this is the information they have given me if i went down the route of ip washers on the pneumatic bulkhead fittings:

If going down this route, the full suite of additional tests would be as follows:
1. 28 days thermal endurance to heat and humidity (~80C, 95% humidity)
2. 24 hours thermal endurance to low temperature (~-10C)
3. 1 kg rounded impact weight dropped onto fitting / washer / housing assembly at low and high temperatures from 70 cm height
4. IP dust test to 6X (or 5X)
5. IP water test to X4 / X5 / X6
Other parts of the equipment assembly already have their IP ratings, so a test sample for this could consist of e.g. an empty IP66 box with two sets of the fittings installed – we only need to specifically test the IP rating of the fitting and washer against a flat metal surface.

so at least an extra month with a whopping price tag.

 

[cairnsafety]

Hi,

Not sure if you found a solution to this but I would suggest looking to change the design to one of the below:
-Design the pnuematics out of the ex'e' enclosure, only have electrical entries, any devices wil have to be ATEX certified though.
-If the pnuematics are inside the ex'd' enclosure use sintered material to provide entry while allowing an adequate flamepath. This is standard methodology for gas detectors.
-Use ex'p' protection method. This will allow pnuematic entry and eradicate the need for ex'd' but ti does come with it's own draw backs.

http://www.cairnsafetytechnology.com