C1D2 Boundry

[gmayeux]

Based on 501.15 (B)2 when a conduit leaves a classified area into a unclassified area there shall be no fitting used between the seal and where the conduit leaves the classifed area. My question is i need to pennetrate a 3/16" steel plate wall to enter into a unclassifed area where the control panel is housed. what are my options for properly passing through the wall it seems everything would be a code violation
1. welded coulping it the wall
2. classifed bulk head fiiting
3. weld a ridgid nipple into the wall
does welding void the UL rating on the fitting, there has to be something that will work, i need advice Thanks,

 

[rbalex]

With regard to welding see 300.18(B).

Does 501.15(B)(2) Exception 3 apply?

 

[rbalex]

I?m sorry I didn?t have much time earlier to answer the quest fully.

The reason I asked about 501.15(B)(2) Exception 3 is that if it doesn?t meet the Exception, it may be difficult to justify the inside classification in the first place since the bulkhead wall may not be ?vaportight.? Unfortunately, while it is used throughout Chapter 5, and several other NFPA and API documents, ?vaportight? is not well defined. Nor is it defined in Merriam-Webster Collegiate? Dictionary, 11th Edition.(The NFPA Manual of Style reference for general definitions) It becomes somewhat of an intuitive exercise.

Assuming though, that you have an adequate fire stopped penetration and that there is no significant air pressure difference then a simple seal in the conduit on either side of the wall per the rest of 501.15(B)(2) would be sufficient. Remember ??uch seals shall not be required to be explosionproof but shall be identified for the purpose of minimizing passage of gases under normal operating conditions and shall be accessible.? (Last sentence in 501.15(B)(2))

 

[don_resqcapt19]

Bob,

Assuming though, that you have an adequate fire stopped penetration and that there is no significant air pressure difference then a simple seal in the conduit on either side of the wall per the rest of 501.15(B)(2) would be sufficient.

I think the issue is the fact that the boundry is defined as the bulk head and there will be some type of theaded fitting between the boundry and the seal making a violation of 501.15(B)(2). I note that this is a very common installation in the field.
Don

 

[gmayeux]

looking at the bulk head i do not think a fire seal will fly with plant inspector,the unclassified area does fall into ex.3 in most cases, but these buildings are built with a blast rating so i am think a fire seal would affect the intergrity of this, we have typically used a bulk head fitting until a inspector rejected it. If ex. 3 does not apply is there approved way to make this work. Thanks,

 

[rbalex]

Occasionally, we get painted into a corner and, if this is a blast proof bulkhead, Exception 3 had better apply; otherwise the conduit should have not penetrated the wall at all. You may need your Structural Engineers to assist in evaluating the integrity of the wall after it is penetrated.

 

[bobgorno]

Is the wall blast-proof, or a "blow-out" wall? A blow out wall, should technically not be penetrated. Hampering of the blow-out wall can effect the intended function.