[LatencyMachine]

I have to add a sanitary tee fitting to a PVC 3" vertical waste stack. I haven't cut into the pipe yet, but I'm reasonably certain that I'm not going to have enough slack or play in the either end of the pipe to work in a PVC fitting and cement it. From reading this forum it sounds like a no-hub of flexible coupling is exactly what I need. So my question...

Should I use a so-called "flexible coupling" like these : Fernco Flexible Coupling, fernco, fernco coupling, fernco couplings, fernco fittings, Sewer Flexible Coupling, Plumbing Flexible Coupling, Drain Flexible Coupling, Waste Pipe Flexible Coupling | Fernco or what they call a "no-hub" coupling like these Fernco No Hub Coupling, fernco, fernco no hub coupling, fernco coupling, fernco couplings, No Hub Connect Coupling, No Hub Flexible Coupling, No Hub Shielded Coupling | Fernco ?

I've looked at both of these in the hardware store, and the flexible couplings are a thick "flexible PVC" but the inside is straight walled. The no-hubs are a thin rubber, but contain a thin metal shield around the outside. The no-hubs also have a 'collar' in the middle on the inside, much like a regular PVC coupler.

I don't really care about the price of the fittings, I just want to use the one that will make the highest quality connection (ie. Do It Right The First Time)

Thanks!

[speedball1]

You do not use a flexable coupling on a vertical stack. You need the ridged support that a shielded coupling,(see image) will give you. Good luck, Tom

[massplumber2008]

Professional names for the shielded clamps are MISSION or PROFLEX clamps. Available at most home improvement stores or guaranteed to find at a plumbing supply house... ;)

You will need a 3" plastic to 3" plastic... ;)

Good luck...

MARK

[LatencyMachine]

Thanks for the answers guys. Exactly the kind of info I was looking for!