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

Table 5-6. Annular Gap Measurements (Columbus 8-in. Liner)
North End of South End of North End of South End of
Specimens Specimens Remaining Remaining
Location
(mm) (mm) Pipe (mm) Pipe (mm)
Crown 0.30 0.39 0.41 0.51
45° between crown and right
spring line
0.16 0.27 0.23 0.53
Right spring line 1.27 0.30 1.14 0.33
Right haunch 0.10 0.49 0.20 0.43
Invert 0.12 0.36 0.18 0.10
Left haunch 0.39 0.10 0.43 0.13
Left spring line 0.34 0.30 0.28 0.20
45° between crown and left
spring line
0.37 0.18 0.41 0.36
Figure 5-7. Histogram of Annular Gap Measurements (Columbus 8-in. Liner)
5.2.9 Liner Thickness. A total of 320 readings were taken to measure the liner thickness at
different locations around the pipe circumference. These readings were taken using a micrometer with a
resolution of ±0.0001 in.
The average thickness of the liner at different locations is shown in Figure 5-8. The thickness at the
crown (5.7 mm) was found to be similar in thickness to the other locations (invert and spring line) around
the circumference of the liner. The average liner thickness for each location is slightly less than the asspecified
liner thickness of 6.0 mm. Additional discussion of the data measured at the time of installation
with the current data is given in Section 5.2.14.
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