Cl1 Div 1 to Div 2 transition

[robobbob]

Hi
this is a project at a local garbage dump. The ground is considered Cl1 Div1 due to gas emissions from the decomposing garbage, and the specs call for HDPE with fusion fittings underground. I am running to a vault, which is Div2, where the engineer has called for sch80 PVC for corrosion resistance.
I need to install a fusion HDPE/PVC transition fitting to go from HDPE to PVC, and then install a seal.To do that I need to install a male adapter on the transition fitting to attach the seal, but the code calls for no other fittings, not even a coupling, before the seal leaving the Div 1 area. How can I attach a seal to a piece of PVC without a fitting? The code talks about threaded steel transitions for below grade PVC transitions to above grade work, but steel is not in the picture for this spec, its all plastic. thanks

 

[rbalex]

I don't say this often but about all I can say at this point is your spec/design has painted you into a corner.

I would like to know the standard used for classifying the underground. If it wasn't one listed in Section 500.4(B) FPN/IN No 2, then it is based on a gross misunderstanding of Section 500.5

 

[nhee2]

Is HDPE allowed in Cl I div 1 locations?

 

[rbalex]

Is HDPE allowed in Cl I div 1 locations?

No; not even under 501.10(A)(1)(a) Exception.

 

[robobbob]

I don't say this often but about all I can say at this point is your spec/design has painted you into a corner.

I would like to know the standard used for classifying the underground. If it wasn't one listed in Section 500.4(B) FPN/IN No 2, then it is based on a gross misunderstanding of Section 500.5

Thank you for responding quickly, though, if I were not in a corner, I wouldn't need an expert

I should start with saying this is a government project, ie they are the AHJ. I do not know the process they used to arrive at the classification, but the actual "dirt" itself is potentially hazardous. There is an underground methane collection pipe system that literally "pumps" the gas out of the ground, like a reverse leachate-septic drain field. The AHJ has determined that fusion sealed HDPE constitutes a singular continuous conduit system along the lines of 501.15 (A)(4) Ex 1 that is acceptable to pass through this "zone", but upon leaving the ground and entering into free air is equivalent to passing through a CL1 zone. In this instance I am entering an underground vault that they considered sealed, but that has been labeled CL2. I could ask for a waiver, they are the AHJ after all, but it would be much better if I could find a code compliant way to just do it and move on. The last thing I need is to open some can of worms over their internal engineering/political process.

 

[rbalex]

Sorry, but under the conditions you cited, there is no Code compliant solution.

I've done methane reclamation/collection. I've done land fill reclamation. I have done Los Angeles/Long Beach shore line methane reclamation. I have done refinery methane reclamation. In one case it was for soil so contaminated that it could have been processed as shale itself. I have done non-nuclear waste processing facilities. I have always managed to achieve a Code compliant design.

Bad design usually begins with not knowing how to properly classify. Then attempting to avoid installing as required. That appears to be the case here. I wish I could be more encouraging.

 

[robobbob]

Sorry, but under the conditions you cited, there is no Code compliant solution.

I've done methane reclamation/collection. I've done land fill reclamation. I have done Los Angeles/Long Beach shore line methane reclamation. I have done refinery methane reclamation. In one case it was for soil so contaminated that it could have been processed as shale itself. I have done non-nuclear waste processing facilities. I have always managed to achieve a Code compliant design.

Bad design usually begins with not knowing how to properly classify. Then attempting to avoid installing as required. That appears to be the case here. I wish I could be more encouraging.

wow, thats certainly discouraging. if this forum can't find a way, at least I know that I've done everything reasonably possible to find it. I'll just drop it in their court then. thank you