Which coupling for 3" PVC to 4" Cast Iron

[takelargebites]

I need to connect my new 3" PVC drain line to the old 4" cast iron drain. The pipes are on the horizontal in the basement. Which Fernco coupling would be preferred? The 1056-43 Flexible coupling or the ProFlex 3000-43 ? It looks like either coupling would accomplish the same thing but it seams like the ProFlex would be more resistant to shear since it's banded.

[hj]

You are correct, especially since the "Fernco" cannot be used for that application.

[mtcummins]

I believe what hj is referring to is that you MUST use a banded adapter underground. Above ground, you could use the reducing Fernco w/o a band.

[Terry]

Above ground is when you need a shielded coupling; required by code.

Plumbers always use shielded couplings.
There are times in the ground, when you can use a non-shield coupling, since the ground is supporting.

When you join pipes, it's important to measure the OD of the pipe.
A new 4" cast iron pipe would be 4-3/8" OD
An old 4" cast iron pipe can be as small as 4-1/8", which is considered a copper pipe size.
If I have copper pipe size cast, then I use a mission copper coupling x no-hub. Which does work with PVC if it's standard waste sizing.

[mtcummins]

Above ground is when you need a shielded coupling; required by code.

Plumbers always use shielded couplings.
There are times in the ground, when you can use a non-shield coupling, since the ground is supporting.

When you join pipes, it's important to measure the OD of the pipe.
A new 4" cast iron pipe would be 4-3/8" OD
An old 4" cast iron pipe can be as small as 4-1/8", which is considered a copper pipe size.
If I have copper pipe size cast, then I use a mission copper coupling x no-hub. Which does work with PVC if it's standard waste sizing.

I stand corrected. I was told wrong...

I generally only use banded ones myself, but thought they were only required underground. Thanks Terry, gotta keep learning!

[hj]

quote; I generally only use banded ones myself, but thought they were only required underground.

That is the ONLY place they are NOT required, but usually outside the building.

[SewerRatz]

In Illinois shielded couplings are required underground. And above ground we are allowed to use no-hub couplings but must use a no-hub transition adapter on the PVC and or ABS pipe.

[hj]

When I was in Chicago, we never used PVC, ABS, OR No-Hub cast iron.

[takelargebites]

My cast iron measures 4-1/4" OD. Does it sound like a Mission CP 43 (4" CI to 3" PL, ST, or XH CI ) would be the way to go? I'll see what the supply house has tomorrow morning and then track down an inspector to get his ok too.

[SewerRatz]

When I was in Chicago, we never used PVC, ABS, OR No-Hub cast iron.

I did not say Chicago, said Illinois. When I work in Chicago, we do not use PVC, ABS or no-hub. Still lead and oakem.