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296     Cha pte r  Se v e n


     7.6  Pipe Plugging or Bypass Pumping
          Bypass pumping of the existing fluid is required for the installation of
          CIPP. With most small diameter pipelines, plugging may be adequate,
          but must be monitored on a regular basis to prevent flow backups.
          Service connections in the residential systems typically do not require
          bypass pumping. The homeowners are notified usually a week or
          two in advance and again 24 hours in advance to refrain from heavy
          use of water while the CIPP installation process is underway. A small
          amount of water from the service connection typically will not affect
          the installation of the CIPP. In commercial and industrial applications
          it may be necessary to bypass flow from each individual service con-
          nection, since flow interruption may not be an option. In these cases,
          individual cleanouts are identified and a small pump is set-up direct-
          ing the flow to the mainline bypassing. In most cases, the project
          owner will require a pumping capacity that is equal to the anticipated
          peak flow (either recorded or anticipated) for the line section, plus
          50 to 100 percent redundancy in the event the primary system fails
          to function. Most pump rental suppliers will determine bypass
          pumping suction and discharge configurations and setup require-
          ments at the jobsite. However, pumping operations for the duration
          of the project is typically the responsibility of the general contractor.
          Figure 7.7 illustrates typical bypass pumping setup for a large vol-
          ume of existing flow.






























          FIGURE 7.7  Typical bypass pump setup for a large volume of existing fl ow.
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