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Cast iron or ABS?

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  • Cast iron or ABS?

    Hi everyone,
    I'm replacing my old defective ABS drains with no-hub cast iron. I'm using new ABS for the vents. I'm following the path used by the original DWV. I've reached a point where I may need to transition back to ABS for one of the 3" second floor toilets.

    The problem is the space where the 3" riser from the 1st floor 90's into a 3" wye to serve the two toilets and shower/tub of the 2nd floor. The original ABS was about 20" horizontal from the 90 to the center of the first toilet. Also, I have to put a 2" vent between that closet bend and that 90. The original ABS setup to this toilet used a 3 x 2 street santee (vent) into a 3" street 45 into the 3" wye.

    My question is this....
    Are there situations where ABS is advantageous over no-hub cast iron such as lack of space?

    It seems that plastic may have the advantage over cast iron in getting some fittings closer to each other such as a street into a street.
    Any thoughts?

  • #2
    Re: Cast iron or ABS?

    cast vs abs... the age old question.... there are pros and cons to both but the best ones r as fallows... cast iron isnt as noisey as abs when used, and the best is cast iron doesnt smolder and melt in the case of a fire and thus keeps a fire rating and the vapors from abs are the ones that get you. Abs is easy to cut, install and join where as cast iron is not with the joining of mj bands and the weight of the fittings with cast iron... in saying that u can rotate, move , recut c.i. casue every joint is a union where as once u glue abs and u mess up.... your using a coupling and starting again.... either way they are good systems and function well....

    Have fun

    if u cant bedazzle em with briliance, baffle em with bulls&*t


    • #3
      Re: Cast iron or ABS?

      plastic stays clean longer and will not rust up.

      a properly installed and strapped abs, or pvc system will outlast a cast iron/ no hub system. it's also much easier to clean and stays clean longer.

      like said prior. cast/ no hub is quieter and better if exposed to a fire.

      if it was my house, i would plumb it in plastic and properly insulate/ isolate and fire caulk if required.

      we are required to now install 1.28 gallon per flush toilets. cast will never last or stay clean with low flow toilets.

      plastic will.

      phoebe it is


      • #4
        Re: Cast iron or ABS?

        there's plenty of things in the average house that make deadly smoke in a structure fire....

        If smoke is your concern, your carpet will likely kill you before your plumbing will.

        Install smoke and CO alarms, TEST THEM... have 2 ways out, and stay low in smoke.

        Pro's and con's for each types of pipe... my vote is ABS

        For more ranting about fire science, just ask