Alarm Horn in Type X Purge Enclosure

[fifty60]

For an Type X Purged enclosure that will be going inside a Class I Div 1 location, would an alarm annunciator (please see link below) be allowed to be installed through the panel wall? I know the back will be sealed, but my concern is with the openings on the front of the alarm.

http://mallory-sonalert.com/SearchSeries.aspx?Code=30ST

 

[fifty60]

They are nema 3R, 4X, 12 with approved gasket.

 

[petersonra]

why would the openings on the front be an issue?

 

[fifty60]

I do not understand why the openings are there. I know that when they are covered the sound is greatly attenuated. My knowledge of acoustics is lacking, but there has to be an electric signal causing something to vibrate that is inside the opening...not sure if it is an issue

 

[don_resqcapt19]

In my opinion, if any part of the device is in the classified area, then the device must be suitable for that classification. I would not accept your proposed installation.

 

[petersonra]

In my opinion, if any part of the device is in the classified area, then the device must be suitable for that classification. I would not accept your proposed installation.

how would you feel about it if it was a pushbutton or selector switch? there is part of the PB or SS that extends outside of the enclosure.

you are suggesting in effect that only explosion proof (or perhaps IS) devices could be installed through the wall of a purged cabinet in a CID1 area, so as a practical matter nothing can be installed through the wall of such a cabinet.

 

[don_resqcapt19]

how would you feel about it if it was a pushbutton or selector switch? there is part of the PB or SS that extends outside of the enclosure.

you are suggesting in effect that only explosion proof (or perhaps IS) devices could be installed through the wall of a purged cabinet in a CID1 area, so as a practical matter nothing can be installed through the wall of such a cabinet.

That is a good point, but I see a difference. With the push button or selector switch that is extending through the panel wall. With the sounder, you have the electronic device in the classified area.

 

[rbalex]

I'm not a big fan of Type X or Y schemes especially but, philosophically, a purged/pressurized application that forces the purging medium throughout an external device should be suitable.

 

[don_resqcapt19]

I'm not a big fan of Type X or Y schemes especially but, philosophically, a purged/pressurized application that forces the purging medium throughout an external device should be suitable.

I am just not sure that would be the case for a device like is being suggested. It appears that the back side, the side in the pressurized enclosure is epoxy sealed.

 

[rbalex]

I am just not sure that would be the case for a device like is being suggested. It appears that the back side, the side in the pressurized enclosure is epoxy sealed.

There are definitely limits to the application. As I said, that's a "philosophical", not necessarily inherently automatic, concept.

Personally, I prefer passive (explosionproof, hermetically sealed, etc.) rather than active (purged/pressurized, gas detection) protection techniques. There is far less to go wrong even if the active systems are properly installed. I have used all of them successfully at one time or another though.

 

[Smart $]

I am just not sure that would be the case for a device like is being suggested. It appears that the back side, the side in the pressurized enclosure is epoxy sealed.

I've seen those type of audible alert devices rated to CID2, but not CID1