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Suggestions Sought to Remove Gravel in 4" Line

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  • Suggestions Sought to Remove Gravel in 4" Line

    Hello to other professionals and thank you for your fine contributions to the drain cleaning craft.

    My thanks especially to 'Plumber Rick' who has made an enormous personal contribution of time and effort in delivering much sound, constructive input on many, many topics. (Do you accept Internet payments so I can buy you a beer?)

    Our firm's primary focus is installing cured in place piping (CIPP) in 1.5" to 8" pipe of any kind, usually sewer lines. To perform that work we regularly have to remove dense tree root masses from 4" and 6" clay tile pipe.

    In these situations, our equipment of choice is the Ridgid K-1500, Model A, Sectional Machine using the T-13/T-14 sawtooth cutters to drill through large root masses. We follow that by finishing up with the T-15A expanding cutter.

    (Our Ridgid SeekTech Line Locator, Mini SeeSnake Camera and LCD monitor (the one with the poorly performing, now obsolete, Liton DVD recorder) are the other primary, important tools of our trade. We also have a first purchased, K-60 Sectional machine, but didn't find it suitable for the root infested 6" clay laterals that we regularly encounter.)

    However, we routinely get involved in other, rather unique drain pipe problems which test our equipment and problem solving abilities. Hence today's submission.

    One such current situation is a 1960's commercial building whose internal storm water removal system consists of a complicated network of 4" and 6" cast iron/steel pipe running from the roof water leads (RWL), 6' under the concrete slab floor and to an external 6" clay connection leading underground to a city storm water connection.

    A considerable quantity of approximately .25" - 1" diameter gravel from the flat roof has entered through the RWL's. It's become lodged in the 4" section of pipe before it joins the 6" line about 8' away which then exits the building some 60' away. The gravel is about 2" in depth throughout.

    In addition, heavy calcite deposits had formed within the 4" and 6" lines, effectively blocking the 4" line along with the gravel. While much of the calcite has been removed, some still remains in the 4" lines of gravel.

    To date, after much investigative work, we have:
    - brought in a flusher truck to remove all calcite from the 6" pipe using a unique, sawtooth cutter that is a larger version of the Ridgid T-23 spiral bar cutter.

    We thought that was a good decision, once we realized the extent of the calcite. Within one hour they were able to clean 60' of calcite away to the original, 6" pipe face. Cost was about $1,200 for a three hour time period that included travel.

    - used the K-1500 and T-24/T-25 4 blade cutter to remove the majority of the calcite in the 4" and 6" sections, and to move some of the gravel from the now, partially blocked 4" into the cleaned up 6".

    Apparently, the flusher truck's nozzle are unable to make their way upstream from the 6" into the various 4" branch lines that 'Y' connect into that 6" line.

    Upstream, the 4" lines are accessible only through one vertical clean-out in a 4" RWL that runs approximately 20 ' to the problem, and that has 2/3 elbows between it and the problem area below.

    The only other nearby access is through a 4" pipe in the sump pit that has three 'Y' connections, calcite build-up and some 60' before reaching the problem area.

    I'd like to move more of the gravel build-up from the 4" pipe into the now cleaned 6" pipe, if not remove it entirely.

    My thinking is that moving it forward into the 6" pipe should lessen the risk of the gravel jamming again from the incoming flow from the RWL's.

    Any suggestions on how to proceed?
    Q. Is a portable jetter the answer? I saw the 'Rocks in the drain' thread discussing this.

    Q. Any success with other K-1500 tools that might be quicker, more effective than pushing the gravel stones forward with the 4 blade cutter?

    I'm annoyed that I overlooked using a 4", T-43 flue brush that I had recently purchased to experiment with in cleaning up remaining tree root tendrils and other possibilities. I would be interested in experiences with this tool.

    Q. What K-1500 cutters have proved successful for removing calcite effectively?

    Q. Another option we've considered is constructing a rubber plug with our CIPP materials and pulling it through the line as we do with our lining, to pull/push the gravel out to the 6".

    Has anyone tried something like this?

    Q. Any experience with the manner in which gravel of this size might behave over a number of years? Will it gradually work its way down the pipe somewhat evenly, or pile up to constrict water flow?

    Q. Any success in getting a garden hose with a nozzle attachment through a long run of pipe with several bends? How far, what type of hose and pressure?

    Q. Any other ideas out there?

    Looking forward to your input in trying to solve this problem.

    ...Sincerely, Dave

    2010/11/30 Update:

    Thank you all for your wonderful input. I do appreciate it.

    I've since reviewed the next steps with the client, a local construction company managing the project. They've now decided against further work for a few reasons.

    They were already over budget before this problem was recently identified. It's a limited $3 million, government funded renovation for a non-profit organization that began in January and is to wrap up in December.

    (And yes, the assortment of contractor, engineer and architect now realize that they should have had this plumbing inspection work completed much closer to the start than right at the end!)

    It was originally to extend the life of this 50 year old building for 5 years, but they've already pushed that to 10 during the current project. No doubt it will end up being stretched further as that decade passes.

    Also, our efforts to date have opened up the 4" line of most of the calcite, and all in the 6" from the flusher, while also evening out the gravel in the 4" somewhat.

    So, there is flow, but it is reduced, and certainly better than when we arrived and it was backing up within the system.

    Overall, I think their decision is a reasonable one. I said as much in my report to them, but I wanted them to fully understand the risk and the available options in making their decision. It was a question of deciding when enough was enough.

    I did point out to the customer, that if the problem does reappear in the future, we only lose the currently excavated area at the downstream end of the 6" pipe outside the building. And there, a new upstream and downstream clean-out are being added upon my recommendation.

    However, I was striving for more, and even 100% if that could be done cost effectively. Your suggestions have given me much to think about if/when they might call us back in the future, and for similar circumstances at other locations.

    This was one of our more challenging projects and a great learning experience...yet again!

    Thanks again for the contributions! Your promptness and quality certainly make this forum a great go-to location.


    P.S. I hope to post a schematic once I've updated it with the current details for the client.
    Last edited by PTS; 11-30-2010, 08:54 PM.

  • #2
    Re: Suggestions Sought to Remove Gravel in 4" Line


    -Try a Chain knocker head on your K-1500 and flush the lines with plenty of water...

    -I have been told that a warthog head on a good sized jetter will also strip scale... By good sized jetter I mean 15-25 GPM at 3000 psi or better trailer jetter not a cart.

    Use a sewer cable to feed a pull rope downstream use this rope to help pull / guide the flusher nozzle upstream use your camera to help also.

    The Ridgid part # for the 6" Chain knocker is a 63115 (T-32) and 63110 (T-31) for the 3"-4"
    Last edited by OkieBill; 11-28-2010, 09:03 PM.


    • #3
      Re: Suggestions Sought to Remove Gravel in 4" Line

      A jetter will work providing that you have proper access.

      I've had little luck pushing with a snake. The best technique I've found using a cable involves flushing with as much water as possible while using the cable to keep it stirred up.

      Using a plug or similar device on a line to pull through may give some success, but I expect what will happen is that, if the plug/drag item is big enough to remove most of the gravel, then as the gravel packs up in front of the plug/drag item it will stop it from moving.

      A jetter would be my first choice. You'll need access into each leg of the system that has gravel in it from upstream of the problem area(s), and access to the common line downstream of the problem area(s). My techniquie would be to jet down through the problem to the lower access, then reverse my hose, installing the nozzle on the opposite end and hooking the machine to what was the nozzle end, so that I can pull the nozzle backwards downstream in the system raking the gravel out and down.

      Other choices might be better dependig on access, etc.

      I have no experience with calcite removal, at least under that name, so really ought not comment. I don't know what calcite is... a mineral deposit of some sort obviously... similar to scale in cast iron? if so, a chain knocker?
      This is my reminder to myself that no good will ever come from discussing politics or religion with anyone, ever.


      • #4
        Re: Suggestions Sought to Remove Gravel in 4" Line

        The best way to remove rocks is with a combo truck. High Vac with a jetter to stir it up. You can clean alot of pipe in a hurry. Canada is full of hydro X guys isnt it? I pay about 200 bucks an hour. It a good way to recover stuck jetter nozzles too.


        • #5
          Re: Suggestions Sought to Remove Gravel in 4" Line

          thanks for the kind words dave but i'm more of a root beer guy

          are you able to jet from the roof all the way down to a 6'' c/o? basically jet right through the gravel. once you get past the rocks and into the 6'' you can pull the hose out of the 6'' c/o line and then install the nozzle on the roof end. this will allow you to string the hose all the way from the roof to the 6'' line.

          i've done this before and as long as you can grab the hose from the 6'' c/o, then you can pull the jetter nozzle all the way back out. it also allows you to video from the roof as you reverse jet the system. a second person with a set of radios or cell phones will make simple work out of it.

          i think i can picture the layout. but please draw an isometric or a flat drawing of the system with openings, pipe direction, gravel location and pipe size. if we can picture it properly, we can come up with a solution.
          either scan it in or take a decent photo to post it here.

          enough root beers and milkshakes would motivate me to take a road trip

          phoebe it is


          • #6
            Re: Suggestions Sought to Remove Gravel in 4" Line

            Originally posted by PLUMBER RICK View Post
            thanks for the kind words dave but i'm more of a root beer guy

            enough root beers and milkshakes would motivate me to take a road trip

            if you would have said this to me i would had you come for my demo

            My seek the peek fundraiser page


            new work pictures 12/09


            • #7
              Re: Suggestions Sought to Remove Gravel in 4" Line

              I would suggest a jetter for this job with a warthog or a root ranger.

              Both have given me good results with anything from sand to rocks in drains.

              Good luck and let us know how you go and what worked for you.

              Cheers Phil.