New standards for testing and certifying cured-in-place pipe (CIPP) as watertight

Abstract

The use of Cured-In-Place Pipe (CIPP) and other trenchless lining solutions have been an accepted method for pipe rehabilitation for over 40 years. Despite the requirement to submit sample pieces of liners or coupons with final video files from high resolution Closed-Circuit Television (CCTV) cameras, a growing number of CIPP lining projects in North American, Europe, and the Middles East have been experiencing liner failures and leaks, before warranty expiration. While most CIPP testing has been limited to simple visual inspection, a number of academic and consulting engineers have sought alternative testing methods to ensure that gravity (sewer) & pressurised pipe (water) liners are watertight, even after lateral reinstatements. One such testing standard gaining rapid adoption has been ASTM F2550, Standard Practice for Locating Leaks Using the Variation of Electric Current Flow Through the Pipe Wall. Similar to holiday testing of protective coatings, low voltage conductivity or Focused Electrode Leak Location (FELL) is recommended as an alternate to visual inspection due to its unbiased results and ability to find and quantify leaks in full-length, 360-degree pipes, in minutes. This paper presents new inspection, testing, and acceptance standards for CIPP and other pipe mate-rials. Oftentimes visually accepted by CCTV cameras, substandard trenchless materials, poor installation, and uneven curing leads to CIPP having accelerant burns, accidental cuts, bad service reconnections, blisters, delamination, damage from equipment, embedded foreign objects, pinholes, overcooking, stretching, wet-out failures, and wrinkles, including buckling, fins, folds, & ridges. This paper discusses case studies from working with WRc plc (Swindon, England), research undertaken with IKT (Gelsenkirchen, Germany), and North American projects, included measuring ‘same-day’ CIPP rehabilitation effectiveness.

Techniques