Flexible Couplings OK for Sewer Drain Usage?

I had someone replace two toilet flanges and the plumbing underneath as they were all rusted and unusable. It looks like for the connections for plumbing pipe underneath both toilets they used rubber flexible couplings for the connections instead of solid connections. The couplings say Fliexible Coupling FC-33.

Is this OK or is it more likely to leak in the near future? Should I have a different plumber come replace those with the solid pipe before we put sheet rock back up on the ceiling?

Thanks in advance.

Those are not allowed.
If you are using a rubber coupling it needs to be fully shielded

The reason they used those couplings is because it appears they were trying to work with two fixed ends. Those couplings make the job easier because they can slide over the pipe. Any shielded ones I’ve used have a stop in the middle.

I prefer shielded. But if those couplings are used properly and supported closely on either end to prevent sagging then you won’t have problems. They are allowed by my code.

Hmm. Interesting. Should I ask them to change out for a shielded coupling? How do I know if they're "allowed" in CT?

He said it was used because we went from black to white pipe, and it's a different type of material that cant be glued together. Also that it's drain so is not pressurized and does not have constant water all the time so is not an issue to use the flexible couplings. Sound valid? It also looks like they're pretty common on sewer usage: https://www.fernco.com/plumbing/flexible-couplings

Just to put it in perspective those are garbage couplings you buy from Home Depot if he was a professional plumber he would have used a shielded coupling or he would have done all the plumbing in the correct pipe that was originally there so we would not have had this problem if it were my house I would tell him to rip that garbage out

A shielded coupling would have been the correct way to go. The fernco couplings are for underground only here. They could have
used the shielded to go from abs to pvc also.

They make “transition glue” to go from pvc to abs. It is allowed in Oregon. It is green and we carry it on our trucks for certain situations. Why didn’t he just use the same material? Easy peasy done.

I can’t tell which way I’m supposed to orientate the photo. Is that a horizontal drain or vertical?

And yes you can certainly bond ABS pipe to PVC. Fun fact though any transition glue I’ve ever saw is white, not green. Fancy!

The reality is that unshielded couplings do not provide any lateral shear resistance, and so as many of us plumbers have seen, can offset readily given the right stress and age.
- The Uniform Plumbing Code does not allow them because they are potentially capable of sagging.
- Jurisdictional issues aside, I would feel ok keeping it, if it were fully and properly supported with pipe straps and wood spacers. If metal straps are used, a 20 mil tape should interface/protect the plastic pipe.

commguy everything in that ceiling is wrong, you are using a san tee instead of a combo and you have a tee as a drain on its back we can help if you rip it all out and do it right, but i will not tell you how to do it wrong

Matt30 said:

I can’t tell which way I’m supposed to orientate the photo. Is that a horizontal drain or vertical?

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, that is the bathroom upstairs.

''I had someone replace two toilet flanges and the plumbing underneath as they were all rusted and unusable. It looks like for the connections for plumbing pipe underneath both toilets they used rubber flexible couplings for the connections instead of solid connections. The couplings say Fliexible Coupling FC-33.''

I believe it was Mr David who posted a good picture a while back of a poorly supported unshielded coupling.

Thanks for the clarification Frodo

Matt30 said:

I believe it was Mr David who posted a good picture a while back of a poorly supported unshielded coupling.

Thanks for the clarification Frodo

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I thought it was a wall myself,

Matt30 said:

And yes you can certainly bond ABS pipe to PVC. Fun fact though any transition glue I’ve ever saw is white, not green. Fancy!

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Green here that way inspector can tell if you used the right type.

Unfortunately cementing the two different pipes together is a BIG red tag around here.

That’s a little strange. Ever hear the reasoning behind it? It’s been my experience that pvc to abs cement actually creates a stronger bond than abs to abs

How could it be illegal if the transition cement is upc approved? Almost all local authorities will defer to the manufactures specs as long as it’s an approved product.

What inspectors want, inspectors get. They over rule the code book here. Many times I’ve done something they didn’t understand and try and back it up by code....nope, they weren’t having it. I’m sure we’ve all been there. So if they say we want joints sealed with duct tape.....