Retrospective Evaluation of Cured-in-Place Pipe - (NEPIS)(EPA ...
Retrospective Evaluation of Cured-in-Place Pipe - (NEPIS)(EPA ...
Retrospective Evaluation of Cured-in-Place Pipe - (NEPIS)(EPA ...
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4.1 Introduction<br />
4.0: CITY OF DENVER RETROSPECTIVE STUDY<br />
The <strong>in</strong>itial discussions were held with the City <strong>of</strong> Denver dur<strong>in</strong>g August 2009 about the City’s<br />
will<strong>in</strong>gness to participate <strong>in</strong> the retrospective evaluation pilot studies. It was known that the City had<br />
been one <strong>of</strong> the early adopters <strong>of</strong> CIPP l<strong>in</strong><strong>in</strong>g <strong>in</strong> the U.S. The draft protocol outl<strong>in</strong>ed <strong>in</strong> Section 3 was<br />
provided to the City so that they could understand the nature <strong>of</strong> the program and the requested role <strong>of</strong> the<br />
City. After the City <strong>in</strong>dicated its <strong>in</strong>terest <strong>in</strong> participation on August 19, 2009, a face-to-face meet<strong>in</strong>g was<br />
organized and held <strong>in</strong> Denver on September 22, 2009.<br />
At the meet<strong>in</strong>g, the City identified a series <strong>of</strong> sewer ma<strong>in</strong>l<strong>in</strong>es <strong>in</strong> a residential area that had been rel<strong>in</strong>ed<br />
us<strong>in</strong>g CIPP <strong>in</strong> 1984. An additional advantage to the identified l<strong>in</strong>es was that they were <strong>in</strong> alley locations<br />
(low traffic) and that the alley pavement surface had areas that had been identified for replacement. The<br />
City wished to complete the dig up <strong>of</strong> the 8-<strong>in</strong>. pipe and l<strong>in</strong>er before w<strong>in</strong>ter and, hence, the field work was<br />
organized for October 27, 2009. A CCTV <strong>in</strong>spection was made <strong>of</strong> several <strong>of</strong> the sewer l<strong>in</strong>es that had<br />
been rel<strong>in</strong>ed <strong>in</strong> 1984 and the evaluations <strong>of</strong> l<strong>in</strong>er defects seen from those <strong>in</strong>spections are given <strong>in</strong><br />
Section 4.2.17. However, the CCTV <strong>in</strong>spection was not used <strong>in</strong> this <strong>in</strong>stance to pick a particular location<br />
for the sample retrieval.<br />
A second option for sample retrieval was identified as a brick sewer <strong>of</strong> 48-<strong>in</strong>. diameter that had a CIPP<br />
l<strong>in</strong>er <strong>in</strong>stalled <strong>in</strong> 1987. This l<strong>in</strong>er had already had a physical sample removed for follow up test<strong>in</strong>g <strong>in</strong><br />
1995 and, hence, another po<strong>in</strong>t <strong>of</strong> comparison for any degradation would be available. The retrieval work<br />
and re-patch<strong>in</strong>g <strong>of</strong> the l<strong>in</strong>er <strong>in</strong> this <strong>in</strong>stance was carried out by one <strong>of</strong> the local CIPP contractors <strong>in</strong> the<br />
Denver area (Wildcat Construction Co., Ltd.). The sample retrieval for this location was carried out on<br />
May 20, 2010.<br />
4.2 Site 1: 25-year Old CIPP L<strong>in</strong>er <strong>in</strong> an 8-<strong>in</strong>. Clay <strong>Pipe</strong><br />
4.2.1 Host <strong>Pipe</strong> and L<strong>in</strong>er Information<br />
Location:<br />
City <strong>of</strong> Denver, CO: Monroe Street and 1<br />
Host pipe:<br />
st Street<br />
Circular, 8 <strong>in</strong>. diameter, vitrified clay pipe (VCP)<br />
Burial depth:<br />
5 ft (above crown)<br />
L<strong>in</strong>er dimensions:<br />
8 <strong>in</strong>. diameter; 6 mm thick<br />
Res<strong>in</strong>: Reichhold 33-060; an isophthalic, polyester, unfilled res<strong>in</strong><br />
Primary catalyst:<br />
Perkadox 16<br />
Secondary catalyst: Trigonox C<br />
Felt:<br />
Unwoven fabric (similar to products used today)<br />
Seal: Polyurethane, 0.015 <strong>in</strong>. thick (today CIPP l<strong>in</strong>ers use polyethylene coat<strong>in</strong>g)<br />
Year l<strong>in</strong>er <strong>in</strong>stalled: 1984<br />
L<strong>in</strong>er vendor: Insituform<br />
Res<strong>in</strong> supplier: Reichhold<br />
Tube manufacturer: Insituform<br />
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