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  • no hub cracks and splits

    no hub cast iron is not all it's "cracked" up to be.

    how many times have i come to a job that's 5 to 20 years old, only to find the no hub piping is split. not only split, but spread open. i didn't know that this pipe is flexible. typically i see it on the top of the horizontal pipe, but also less common on a vertical line.
    this is not affecting any 1 brand of pipe either. i see it more on roof and area drains. sanatary waste lines are not as common.

    any suggestions as to what causes this and how to prevent this?

    rick.

  • #2
    I thinkI 'd be taking a close look at how the piping is supported. Most of the time on small jobs I would bet this stuff (supports) is "field engineered" based on past experiences and 'what worked before'. I'm not sure but I'd bet in CA that supports are looked at pretty closely because of seismic concerns which in most orther states is not a concern, at least ot the degree that it is in California.

    Anyway, are riser clamps installed where they should be and is the pipe in horz runs supported adequately? It may not be falling down but that does not necessarily mean it meets design requirements.

    Are hangers and supports just that or are they anchors? In other words, is the pipe allowed to move with differences in temperature (ambient and process fluid (waste water) temps need to be considered) where it needs to and locked down (anchored) in other places to control the direction of growth. I know we are not talking about steam piping here but large deltas in ambient temps can cause considerable growth too.

    Used to be the old hub and spigot pipe was not 100% good stuff. Once they went to 'spun' pipe the wall thickness became more uniform and laminations in the pipe and uneven wall thickness went away for the most part, but I can remember running underground in the 70's that had uneven wall (US made pipe too). We would put the thinner wall at the top when possible. Some times the stuff was just so thin we would bust it up and junk it so as not put the crap in and just write it off a breakage. Sending it back to the shop or the supplier was not worth the trouble. A quick light tap with a hammer or wrench could tell you by the sound of the ring (or thud) if the pipe or fitting was any good.

    [ 12-25-2005, 04:03 PM: Message edited by: Bob D. ]

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    • #3
      just a thought cood it be that the pipe is warmer in a attic and the cooler water runing down the pipe is causeing it have stress crack???
      Charlie

      My seek the peek fundraiser page
      http://observatory.mountwashington.o...nal&fr_id=1040


      http://www.mountwashington.org/weather/conditions.php

      new work pictures 12/09
      http://public.fotki.com/hvachawk/

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      • #4
        just a thought could it be that the pipe is warmer in a attic and the cooler water runing down the pipe is causeing it have stress crack???
        Charlie

        My seek the peek fundraiser page
        http://observatory.mountwashington.o...nal&fr_id=1040


        http://www.mountwashington.org/weather/conditions.php

        new work pictures 12/09
        http://public.fotki.com/hvachawk/

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        • #5
          bob, some good points, but it doesn't apply to these problems. in fact on a large hotel job we did back in 1991, the owner contacted me a month ago. he was concerned that the area drain, planter drain piping was splitting. this is the same piping material, installed at the same time, with the same standards as the sanatay waste system. the waste system has not been an issue.

          i told him that the piping is reacting to the soil and fertilizer. also the lack of a vent pipe will trap these gasses. although the floor drains do vent via the drain.

          this is just 1 example. it seems that i find more issues on roof and area drains than i do on waste lines. also a waste line would be caught and replaced much sooner than a roof drain that is seasonal and typically splits on the top wher it wouldn't leak or show up until all heck breaks loose.

          the interesting thing is that the pipe not only splits, but springs open approx. 1/4''. once again it's strange that the pipe shows elasticity.

          any thoughts or suggestions. thanks bob.

          rick.

          ps. the temperature swing is very minimal here in los angeles and the surrounding areas.

          Comment


          • #6
            Rick,

            I think the answer lies in the quality of the pipe for the most part. Perhaps some stress fracturing is caused by poor pipe support but most likely you are seeing material defect issues MHO. Tyler seems to be making the most uniform C.I. pipe for no hub but it all seems a tad to thin for me. I've some come out on a job so full of sand holes you can see daylight through the side.

            There could be some material handling issues as well. Just finished a small roof drain job and as I watched the driver move our C.I. load to the back of the truck it amazed me how hard he was pushing this stuff around and slaming it against each other, the wall, and the floor of the truck. He broke one in front of us, so one wonders how its treated when no one is watching.

            Quality cast iron will last for 60 years or better. Its still proving itself on installs made in the 20s and 30s that are holding up and strong to this day.

            This is the edited part: Charlotte pipe co. also makes some pretty decent C.I. but ive seen a few of their pieces that looked as though it had some seams i did not like. Still they had the "bell" effect when tapped so I installed them
            Last edited by plumber; 01-02-2006, 01:47 AM.
            Work hard, Play hard, Sleep easy.

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            • #7
              I'm not as experienced as some of you guys speaking of jobs in the 70's and 80's because I'm only 29. I work for my family's plumbing business running the service end of the business in East Texas. I may be completely talking out of my rear end, but what I assumed is the culprit of ci vertical stacks being cracked is lightning skrikes. I had a crew do a smoke test last week on a restuarant and located a crack in a ci vent line that ran from the roof to the first hub at the fixture branch. This is not uncommon. The only other place that ci has been a problem is in restuarants at the soda machine drain. Or floor drain ptraps where over time from cables being ran down them until they finely bust. CI floor drain replacement in restuarants is about a once every other week occurance. In new construction we normally run PVC unless at a hospital or a high end residence we run ci.

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              • #8
                sewerman, lightning? it doesn't rain here in los angeles. woops, well maybe just during the rose parade.
                in my case lightning is not the factor.
                you're right about the soda fountains, have snaked and jetted plenty of them. most don't last too long with sugar.

                welcom to the ridgid forum.

                rick.

                off to the snow this week. wed-sat. i'll give you all a break.
                can't take the computer with me.
                phoebe it is

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                • #9
                  Correct, sugar and high acid fluids are very hard on cast iron. I would like to see schedule 80 cpvc DWV be mandated for all commercial kitchens, at least for the undergrounds. It will withstand 180 heat of the dishwasher and the acids and sugars in the drains.It is also heavy enough to stand up to years of cabling. Of course we would still run no hub pipe in the plenum ceilings.

                  Still proper handling and installation is the best way to insure the longest life possible from cast or any other piping installation. This includes the various plastics as well. On ABS I would not put hangers any less than 32" apart if any hot water is to flow through the line. I have seen that stuff belly out with just bathwater running through it.
                  Work hard, Play hard, Sleep easy.

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                  • #10
                    it snows in la
                    have a good time and do not slip on the ice
                    Charlie

                    My seek the peek fundraiser page
                    http://observatory.mountwashington.o...nal&fr_id=1040


                    http://www.mountwashington.org/weather/conditions.php

                    new work pictures 12/09
                    http://public.fotki.com/hvachawk/

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