Retrospective Evaluation of Cured-in-Place Pipe - (NEPIS)(EPA ...

• Date of rehabilitation
• Rehabilitation technology used (including specific variations such as inverted vs. pull in, use
of a pre-liner, type of cure used [e.g., hot water, steam, ambient])
• Construction records for the selected rehabilitation location
• Inspection reports for the selected rehabilitation location
• Material test data for the materials used in the rehabilitation: manufacturer-provided data and
preferably actual test data on the installed materials
• Any samples retained in storage that were retrieved during the construction process
• Municipal employees familiar with the specific rehabilitation installation.
3.3.4 Retrieval of Field Samples (Dig up and Replace Sample). The type and dimensions of
field samples retrieved would be determined in conjunction with the preferred segments for evaluation.
In the case of an opportunity to dig up and replace a sample, the following protocol was envisaged:
• A pipe sample length of at least 18 in. (preferably at least 36 to 48 in. would be retrieved).
The lined pipe segment would be boxed and shipped to Louisiana Tech University for liner
evaluation and testing.
• The type and condition of the host pipe and the surrounding backfill would be noted during
excavation together with confirmation of pipe depth, pavement type and thickness, and other
factors relevant to pipe loading conditions.
• The orientation of the pipe sample would be marked on the pipe at the time of retrieval.
• Laboratory test samples would be retrieved from these full pipe samples in the laboratory.
• Various in-situ non-destructive evaluation methods would also be applied adjacent to the
removed section and at the manholes at either end of the segment.
3.3.5 In-Situ Evaluation. In the case that dig up and replacement of a segment would not be
possible, the evaluation would be carried out using non-destructive or minimally destructive evaluation
(e.g. coupon sampling) methods. The exact methods to be used were to be determined during the
continuing protocol development, but would ideally include most or all of the following:
• Cleaning of the line and temporary stoppage or bypassing of flow in the segment
• CCTV inspection of the line to carefully document any defects, discolorations, etc.
• Laser profiling for accurate internal dimensional checks of the finished liner (e.g., assessing
ovality).
• Ultrasonic thickness measurements (by hand close to manholes)
• Feeler gauge measurement of the annular gap adjacent to the manhole
• Surface hardness measurements (by hand close to manholes) – if the diameter of the host pipe
was sufficient to apply such measurements
• Physical sample retrieval (if feasible) for laboratory testing of constituent, material, and
structural properties of the liner, e.g., Barcol or Shore hardness, and laboratory glass
transition (Tg) testing to measure the degree of cure, tensile strength, and short-term modulus
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