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

• The municipality would be willing to provide the equipment and labor to retrieve field
samples of a lined pipe for evaluation or field support for NDT of other lined segments.
• Members of the EPA project team would be on site for the sample retrieval and liner
evaluation in the field. The project team would also be responsible for all liner testing and
analysis carried out off site and would provide a report of the data collected and its
interpretation to the municipality.
• The municipality will have the option to not have their name associated with specific data or
analyses conducted.
3.3.2 Identification of Segments for Evaluation
• Ideal segments for evaluation would be where a dig up and replacement of a rehabilitated
segment is planned for reasons other than problems in the rehabilitated line or where a dig up
and removal of a pipe segment can be scheduled prior to street repaving, etc.
• If a dig up and replacement of a segment was not possible, then an area where a physical
sample could be removed from within the line would be considered. This could be adjacent
to a manhole or in a pipe large enough for the removal of a sample with adequate dimensions
for physical property testing (e.g., 2 in. by 6 in. coupons).
• NDT measurements would also be applied to segments where physical samples are removed
to determine if the same conclusions concerning liner properties could be derived from the
non-destructive measurements (either within the line or where the liner was accessible at a
manhole).
• Mainline segments where lateral rehabilitation was planned could also provide an opportunity
to remove samples adjacent to the lateral and then covering the removed coupon areas with a
T-Liner type of lateral rehabilitation that included an integral mainline collar.
• In order to test the application of the protocols and monitor time and cost to perform the
evaluations, it was anticipated that two different line segments would be selected in each
cooperating utility.
3.3.3 Availability of Historical Data. The following historical data would preferably be available
for use in the retrospective evaluation (it was realized that not all the elements of the list below would be
available):
• Location and length of lined segment, slope of pipe
• Type and diameter of host pipe and condition of the host pipe prior to rehabilitation (partially
or fully deteriorated, any recorded ovality, etc.)
• Repair history prior to rehabilitation
• Estimated flow data, frequency of surcharging, and any substantial changes since
rehabilitation
• Soil conditions and/or backfill conditions at the time of pipe construction
• Any evidence of soil voids outside the pipe prior to rehabilitation
• Any special chemical aspects to the wastewater carried in the rehabilitated pipe
• CCTV data pre- and post-rehabilitation
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