Cured-in-place-pipe (CIPP) can serve as a seemingly brand new liner and restore a pipe’s structural integrity, but things can still go wrong after it’s been installed. And the only way to find that out before severe damage ensues is through a visual inspection.
First invented in the 1970’s, cured-in-place pipe (CIPP) is the most commonly used trenchless repair method for sewer and storm pipes. The process involves inserting or pulling a felt or fiberglass liner inside the damaged or structurally unsound pipe. The resin within the liner is exposed to heat or UV light to harden and fit tightly to the pipe’s walls—serving as a new lining to the pipe and “curing” it.
While CIPP is a favorable method for its durability and often cost and time-savings, there are important steps that need to be taken after installation to ensure its success.
Beyond the initial post-installation CCTV inspection, NASSCO recommends another follow-up inspection roughly 6-9 months after installation, allowing enough time for the liner to be exposed to elements but keeping within the typical 1-year warranty period.
When conducting the follow-up inspection, operators should look at the overall physical appearance of the liner, including whether the liner has
- Kept its shape, sagged or ovalized
- Developed bulges or voids
- Loose or delaminated areas
- Tears or fraying at the seams
- Lifting or swelling at the manhole interface
- Signs of infiltration or unusual discoloration
The condition of secondary finishing details should also be observed, according to NASSCO, including
- The grouting or end dressing
- The main/lateral connection seals to confirm they are are still present and securely attached
- The laterals or ends to confirm there is no hanging or trapped debris
If any of these issues are found during an inspection, they should be flagged and communicated to the installer for additional review or repairs.
In addition to inspections, even recently repaired pipes require routine care. Both pipes and CIPP liners alike require regular cleaning and inspections to maximize their lifetimes and avoid unexpected repair costs or significant damage.
“Cleaning and inspecting sewer lines are essential to maintaining a properly functioning system; these activities further a community’s reinvestment into its wastewater infrastructure,” the EPA states.
Utilities are encouraged to develop and follow cleaning and inspection schedules and track maintenance so any issues are addressed proactively rather than reactively, leaving little room for unanticipated costs or catastrophes.
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