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

In summary, CCTV inspection of three parallel 8-in. VCP sewer lines lined using the CIPP lining method
in the mid to late 1980s, was completed. All sewer lines run in the allies between Monroe and Garfield
Streets (Line ‘A’), Garfield and Jackson Streets (Line ‘B’), and Jackson and Harrison Streets (Line ‘C’).
The survey area was bound at the south end by Ellsworth Avenue and at the north end by 5 th Avenue. In
total, 5,797 linear feet of CIPP lined pipe were imaged. A number of defects in the liner were noted by
the operator. With the exception of three locations, all defects appear to be related to poor restoration of
the lateral connections following lining of the mainline, which in some cases allowed for root intrusion
between the outer wall of the lateral and the liner. Another liner defect which was noted on multiple
occurrences was a connection tap shift, potentially due to relative movement of the lateral with respect to
the mainline or movement of the liner within the host pipe. Three liner defect events were identified that
are not related to the restoration of a lateral connection: (1) a bulge in the liner, (2) a detachment of the
liner from the host pipe wall, and (3) what appears to be a tear in the liner, possibly due to inaccurate
lateral restoration attempt (cut is located approximately 1.5 in. from the edge of a lateral connection).
4.3 Site 2: 48 in. Equivalent Diameter Egg-Shaped Brick Sewer
4.3.1 Host Pipe and Liner Information. A 48-in. diameter brick sewer pipe, originally installed
in the early 1900s near Union Station in Denver, CO, was relined with a CIPP liner in 1987 under Denver
Project PCO-609 Union Station. The CIPP-repaired section lies under 19 th Street (see Figure 4-26).
Manhole MH B-3 located at the crossing of the 19 th Street and Wynkoop Street divides the rehabilitated
section into two parts: the lining thickness was 18 mm upstream (270 ft length between manholes B-1 and
B-3) and 13.5 mm downstream (186 ft length between manholes B-3 and B-5).
Figure 4-26. Layout and 2010 Sample Locations for the Denver 48-in. Liner
4.3.2 Sample Removed and Tested in 1995. Insituform Technologies removed one sample from
the installed CIPP liner and tested it in 1995 (at the time the liner was eight years old). The sample was
taken from adjacent to manhole B3 and the liner thickness was measured to be 18 mm. Test methods for
tensile testing were based on ASTM D638 and for flexural testing based on ASTM D790. The results are
shown in Table 4-13. It should be noted that there was some confusion about the data recorded for the
sample in that the sample was marked as coming from an oval-shaped 48-in. equivalent diameter brick
sewer in this location, whereas the actual sewer in this location is circular. Such discrepancies are often
impossible to resolve after many years have passed since the data was recorded. The flexural strength
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