CI to PVC underground drain connection, is PVC adapter needed?

[Jesse Kershaw]

Hi,
I'm connecting PCV to CI, 4", underground. I plan to use a shielded 4-clamp coupling like the Fernco 1056-44rc. Do I need a nipple type adapter on the PVC such as the Spears P119-040 or Charlotte pipe 00119 1400 or do I just use a square cut end? I'm getting conflicting information locally on this. Thank you

 

[wwhitney]

1056-44RC has an ID of 4.58" on each side and is marketed for cast iron or plastic to cast iron or plastic, so with it you would just use a square cut end on the PVC side. That has an OD of 4.5", so the 1056-44RC will fit well. If the cast iron has a smaller OD, you'll end up tightening the clamps on that side a bit more.

I'm not 100% certain, but I believe the "No Hub Adapters" such P119-040 are intended for use with cast iron no-hub couplings. Modern cast iron 4" will have an OD of 4.3", and so a no-hub coupling would not fit properly on the 4.5" OD PVC pipe. The "no hub adapter" has a slightly smaller OD to allow the no-hub coupling to work properly.

Cheers, Wayne