Fireproofing& Conductor Derating

[snace]

During a recent project site visit, I noticed the GC has followed the EC in the corridors and sprayed fireproofing over the electrical conduits. Is there a derating factor found anywhere to compensate for the increased thermal buildup that will occur within the conduits? Thanks.

 

[Dennis Alwon]

During a recent project site visit, I noticed the GC has followed the EC in the corridors and sprayed fireproofing over the electrical conduits. Is there a derating factor found anywhere to compensate for the increased thermal buildup that will occur within the conduits? Thanks.

I don't believe there is. This issue has come up with NM cable in dwellings and the spray foam insulation.

 

[Jraef]

Fire proofing spray on conduit? This must be something new, I only ever did that on cable trays. I don't see the point, I would think if a fire has already reached the point of being dangerous to steel conduit, the fire stop material has become irrelevant. Could be wrong though, it's been a long time.

Oh wait, was it NM conduit maybe? That would make more sense.

 

[iwire]

My guess is when they were spraying the fireproofing onto building steel it also got on the conduits.

This is not an NEC problem and no derating is required.

 

[Jraef]

My guess is when they were spraying the fireproofing onto building steel it also got on the conduits.

That exact thought occurred to me as I was driving in to work after posting that. I was thinking like an EC, he had said it was a GC that did it.

D'oh... :slaphead:

 

[snace]

Correct. The EC installed his work and then the GC came back and spray bombed the hallway. Thanks for all the input, I was just wondering if I was missing something.