CIPP Installation – Preparation of Liner, Calibration Tube, & Pull Strap

Best Practices – 7th in the series

This step picks up where we left off with our CCTV cable “storyboard” to prepare the liner. Here are the steps to measure, mark and cut your tube.

  1. Layout the CCTV camera
  2. Unroll and stretch the liner tube and place beside your CCTV cable
  3. On the camera end, add 6” to the length of the tube by placing the tube 6” beyond the end of the camera lens. Mark the location of the end of the camera lens on the tube. This extra 6” will become your vacuum port for vacuum impregnation of the tube.
  4. Tape the end of the liner at the end of this 6” reservoir with duct tape sealing the end
  5. Cut a ¼” hole in the 6” reservoir for the vacuum pump suction cup to be attached
  6. Where there is tape denoting any tie-ins, you can mark the center of the opening with a marker denoting where they are located
  7. Draw a line on the tube where the liner is to start in the pipe. The cost and location of where you want the liner to start will determine which method below you’d choose.
    1. At this point, you have two options
      1. You can cut the liner here and weld on a leader made of previously used calibration tubes from the beginning of the liner to the inversion unit. This is the remote start method
        1. To perform this method clean the surfaces to be welded with acetone
        1. Overlap the calibration tube approximately ½” over the tube.
        1. Ensuring the flat iron has a temperature of 400F, place the iron over the overlap and hold for 12 to 15 seconds. Lower temperature or less time will result in failure of the weld
        1. Move the iron to the opposite side and repeat.
        1. If the calibration tube is wider than the liner, weld the edges closed using the same temperature and 12 to 15 seconds
        1. Allow to cool, then test your weld by trying to pull it apart.
      1. Your other option is to add liner from the point in the pipe you want the liner to start and the inversion device.
  8. We will use the same CCTV markings to prepare the calibration tube.
  9. On the camera, end add 3’ beyond the end of the camera head. This will be the portion of the calibration tube that expands the end of the liner and ensures it is fully opened
  10. The opposite end or inversion end will extend the length of the liner plus the distance between the beginning of the liner and the inversion gun accounting for any cuffing of the tube used to attach the calibration tube to the inversion device.
  11. Cut the calibration tube and prepare the knotted end as prescribed in the step by step manual or the Pipe Lining Supply YouTube video channel.
  12. Cut the pull strap and, if used, the recirculation hose
    1. Choose the ambient cure knot if curing with air temperature only
    1. Choose the heat cure to know if using hot water to cure the liner
    1. The measurement of the pull strap will be from the end of the calibration tube all the way to and through the inversion device, marking the pull strap where you expect the strap to finish when it is fully inverted. This will let you know that you’ve fully inverted the calibration tube.
    1. Cut the lay flat recirculation hose to a length that will run from the end of the calibration tube to the point where the heat recirculation manifold will be placed during a cure. Too long and you will kink the hose and too short will hold the end of the calibration tube from fully inverting.
  13. Once the calibration tube is prepared, fold in a serpentine manner as you apply SLIC lubricant to the calibration tube. Place aside close to the inversion unit for connection to the inversion unit after the liner tube is installed.

Next “best practice” will be the Mixing of resin, vacuum impregnation and calibration of the liner as described in ASTM F-1216. For more information, call Pipe Lining Supply at +1-888-354-6464 or write to

Tags: , , , , , ,