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  • Flow Failure

    I'm looking for flow tests on all potable water systems.

    CPVC
    PEX-All Brands
    Copper with soldered joints.
    Copper with ProPress type joints.

    What I'd like to find is pressure/failure tests that include flow in the data because flow is one of the primary reasons for wear and failure.

    I can find pressure to failure in laboratory conditions including hydraulic shock. But none that include flow. Seems it should be one of the most important because that's what really deteriorates the distribution piping.

    Example: PEX with crimped joints experiences breakdown of fittings/joints at X PSI & Y GPM over Z amount of time.

    Just thought some might know where to find them or already have them. If I find some I'll link them too.

    J.C.

  • #2
    Re: Flow Failure

    well flow goes hand in hand with velocity we want to mantain a velocty withn the ppes of less than 7 ft/sec, any greater and the ppe wll actually erode, Mark probably has some case studies of ths handy I will have to look and see what I can find

    Comment


    • #3
      Re: Flow Failure

      Originally posted by wrench spinner View Post
      well flow goes hand in hand with velocity we want to mantain a velocty withn the ppes of less than 7 ft/sec, any greater and the ppe wll actually erode, Mark probably has some case studies of ths handy I will have to look and see what I can find

      I must have missed that day at school but how do you know the velocity in the pipe especially at 7 ft/sec. Although the velocity is 7 ft/sec.
      So the question would be what would the pressure be and the draw off to achieve the 7 ft/sec.

      ( It would be good in metric if that is possible)

      Simon

      Comment


      • #4
        Re: Flow Failure

        Originally posted by wrench spinner View Post
        well flow goes hand in hand with velocity we want to mantain a velocty withn the ppes of less than 7 ft/sec, any greater and the ppe wll actually erode, Mark probably has some case studies of ths handy I will have to look and see what I can find
        I've got a job with an acoustical engineer who's specifying a max velocity of 4ft./sec.

        I've done my homework and come up with a few formulas to ascertain velocity in ft/sec when starting with fixture units and pipe sizes. Anyone have an easy algorithm for this calc?

        Comment


        • #5
          Re: Flow Failure

          Originally posted by JCsPlumbing View Post
          I'm looking for flow tests on all potable water systems.
          CPVC
          PEX-All Brands
          Copper with soldered joints.
          Copper with ProPress type joints.
          J.C.
          You might check the CDA site, JC.
          http://www.copper.org/

          Comment


          • #6
            Re: Flow Failure

            Velocity =
            gpm x 0.3208
            A

            where A = area of the pipe, in square inches,

            for 1/2" A = 0.1963
            3/4" A = 0.4418
            1" A = 0.7854
            1 1/4" A = 1.2272
            1 1/2" A = 1.7671
            2" A = 3.1416
            2 1/2" A = 4.9087
            3" A = 7.0686

            and on and on

            to convert DFU's to GPM the ratio is 1.5 DFU's to 1 GPM


            to convert WSFU's to GPM the ratio is 1 to 1

            Comment


            • #7
              Re: Flow Failure

              here is a really good link for everyones reading/learning enjoyment:

              Copper Erosion

              Comment


              • #8
                Re: Flow Failure

                Do you think exterior reaming.cleaning of the pipe ends helps with the longterm performance?

                J.C.

                Comment


                • #9
                  Re: Flow Failure

                  Exterior, no. Most of the copper failure I have seen is on hot water return lines. Most plumbers spend very little time considering what pump should be used thus the excessive velocity of water flowing will start to cavitate the interior of the piping.

                  Comment


                  • #10
                    Re: Flow Failure

                    [quote=wrench spinner;223906]Velocity =
                    gpm x 0.3208
                    A

                    where A = area of the pipe, in square inches,

                    for 1/2" A = 0.1963
                    3/4" A = 0.4418
                    1" A = 0.7854
                    1 1/4" A = 1.2272
                    1 1/2" A = 1.7671
                    2" A = 3.1416
                    2 1/2" A = 4.9087
                    3" A = 7.0686

                    and on and on

                    to convert DFU's to GPM the ratio is 1.5 DFU's to 1 GPM


                    to convert WSFU's to GPM the ratio is 1 to 1[/quote

                    Or you can use one of these:

                    http://www.tasonline.co.za/toolbox/pipe/velocity.htm

                    http://www.calculatoredge.com/mech/p...20velocity.htm

                    Comment


                    • #11
                      Re: Flow Failure

                      That is what i usually use something similiar plumbus, I also have a chart that has that info handy taped up on my computer, i spend a lot of time sizing ejector pumps and booster pumps so i use them pretty much everyday. The Mechanical engineer tells me that flow he needs, and pressure after the pump and I can take care of teh rest!

                      Comment

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