501.15(B)(2) Cl I Div 2 Boundary Seal

[nhee2]

I thought this had been discussed before but cannot locate the thread - 501.15(B)(2) indicates boundary seals at Class I Div 2 boundary shall not be required to be explosion-proof but shall be identified for the purpose of minimizing passage of gases permitted under normal operating conditions.

What methods (for conduit) would be used besides a standard EY/EYS/EYD fitting would be used to meet this requirement?

 

[rbalex]

It has indeed been discussed many times. A keyword search on "ductseal" will reveal several.

That said, the problem with using EY/EYS/EYD/etc., is part of their listing includes using an explosionproof compound and Section 110.3(B) could come into play.

Technically, under Section 500.8(A)(3), a C fitting, packed with ductseal", might be "suitable" - if you could sell it to the AHJ. So far, CMP14 hasn't seen fit to clarify what should automatically be acceptable.

Personally, I believe only a few Class I, Division 2/unclassified boundaries need to be sealed at all - that's why there are so many Exceptions in Section 501.15(B)(2). However, I also believe those few should be explosionproof.