Seeking advice - replacing ABS to cast iron connection

[ProfessionalAmateur]

What is the correct way to replace this ABS to cast fitting? I have two of these to replace, both with 1.5 drain side and 2 in vent side.

I am 99.9% certain there is no lead involved in this setup but I can’t tell for sure and I also dont know if some other substance was used at the cast connection or if it’s just years of paint or crud buitl up.

Options I foresee -
1. Reuse the cast coupling with a threaded pvc adapter (do I use pipe dope or thread tape?). Also replace the shielded fernco.

2. Replace the cast coupling as well as the existing shielded fernco with a shielded fernco to merry the cast pipe and the pvc. My assumption is the existing shielded fernco is on top of a splice in the cast but I won’t know for sure until I take it apart.
Other options or recommendations?

Lastly, I plan on adding a clean out to both pipes when I convert over to pvc.

 

[Breplum]

Replacing the couplings is not so expensive, so that would be the ideal. They make specialty transition couplings for cast iron x plastic; however, in the 1.5" and 2" sizes the O.D. is of no consequence, whereas, in 3" and 4" the O.D.s are actually significantly different between materials...
So, you can buy shielded no-hub couplings and be fine, though some stickler inspectors only want to see the UPC listed transition couplings even in smaller sizes.

 

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[ProfessionalAmateur]

I bought the (crimpled metal exterior) no hub with nsf sticker and (flat, not crimpled metal material) shielded with upc sticker so I will go with the latter.

To confirm, your recommendation would be to eliminate the cast hub and use a shielded fernco to connect the iron to the pvc?

also, thank you for the responses.

 

[wwhitney]

I suggest eliminating as much cast iron as is easy to do. So if the bottom entry to each of those existing no hubs is a plain cast iron pipe end of standard diameter, as would be suggested by the use of regular no hubs, replace those couplings with the proper cast iron to plastic transition couplings to tie into your new work.

Also, if you are putting in PVC instead of ABS, presumably at some point you'll need to connect the new PVC to the old ABS. There's a listed transition coupling for that, too.

Cheers, Wayne

 

[ProfessionalAmateur]

Thank you!

The only remaining abs will be from the kitchen on the inaccessible portion and the proper transition will be used where it’s accessible to converot to pvc. And, possibly on the main stack where the abs enters a cast coupling and lead looks to have been used for that somehow. The correct pvc to abs transition will be used here as well just above that joint.