The expected useful life of nearly any pipe material does not have to be prematurely shortened due to a localized failure. Whether the point of failure is caused by material defect, joint separation or even cross-bore interference, cured-in-place-pipe (CIPP) sectional point repair gives contractors and system owners a structural solution for spot rehabilitation of otherwise competent pipe.
In Providence City, Utah, an 8-in PVC sewer main was damaged when an HDD contractor accidentally bored through it while installing a new underground power service for an upscale residential development. Fortunately, the contractor realized the issue prior to pulling in the new pipe. However, the sewer main now had large 4-inch holes on each side of the pipe. The damaged section was located between two manholes, 120 feet from each other, and it lay beneath a newly resurfaced asphalt road which was the only access to the residential development.
To fix the cross-bore damage, the contractor called upon Claude H. Nix Construction, a specialist in underground construction. While the city would permit an open cut repair, Nix Construction assured the city it was not necessary. Utilizing a trenchless CIPP point repair would eliminate the inconveniences of demolition and restoration.
Prior to starting the repair, video review showed that debris was flowing into the pipe through the 4-inch holes, so the Nix Construction crew used a reverse jet nozzle to remove all debris, making the pipe ready for the point repair installation. To start the repair, the crew mixed the silicon-based resin’s premeasured components, wet both sides of the mat and loaded it onto the packer. Then they connected an air hose to the packer and pulled the repair into place through a nearby manhole, verifying the repair’s position by sending a camera in from the opposing manhole. They inflated the packer, pressing the patch against the pipe, and left it in place throughout a curing period of just over 2 ½ hours before deflating and removing it.
After seeing the recorded video footage verifying the point repair’s successful installation, the city’s Public Works Director said he was impressed by the smoothness of the repair, which he believed was beneficial to flow. A conventional repair, he said, leaves “lips,” circumferential, right-angle ledges at both ends of an “old-school sleeve”. These lips can be debris collection points that restrict flow capacity more than the smoother seam of a point-repair system.
Trenchless CIPP point repair systems from HammerHead Trenchless have a 50-year service life. They are a structural solution compatible with all sewer and storm water pipes 3 to 60 inches in diameter having a circular or oval cross section. They can be used as part of standard CIPP rehabilitation projects to restore the structural integrity of a pipe prior to lining, or they can be used in stand-alone repair applications.
Rather than typical felt CIPP liners, the point repair system is based on premeasured 2- and 4-foot sections of fiberglass-reinforced mat that form a mechanical bond with the existing pipe. Each packaged solution comes complete with everything a two-person crew would need (excluding an air compressor): tarp and nitrile gloves to keep things clean on the worksite, precut material, inflatable packer, premeasured resin components and spreader.
Point repair solutions offer contractors and municipalities greater flexibility in pipe maintenance scheduling and funding. The kits enable inspection crews to make repairs themselves as soon as they discover pipes compromised by cracks, breaks or joint separation. The repair systems permit installation even during active infiltration.
This case study demonstrates that even an extremely compromised pipe that otherwise had many years of anticipated useful life was spared full-length replacement. The repair was successfully completed in 1 day’s work and it didn’t require any excavation at all.
Contact Hammerhead Trenchless for more information.