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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CAC has not taken samples <strong>of</strong> CIPP l<strong>in</strong><strong>in</strong>g after a period <strong>in</strong> service. It has undertaken just one <strong>in</strong>spection<br />
after a period <strong>in</strong> service <strong>in</strong> response to a problem and found both I/I and blockage because <strong>of</strong> a partially<br />
collapsed l<strong>in</strong>er after 8 years <strong>in</strong> service. Further rehabilitation was undertaken to rectify the problem.<br />
CAC has its own specification for CIPP works. This was developed <strong>in</strong> house based on one used by<br />
another municipality and amended to suit the needs <strong>of</strong> CAC. This is a performance specification that sets<br />
material and performance standards while leav<strong>in</strong>g the method itself to the contractor to decide. Design is<br />
undertaken by contractors to meet the specification. Data sheets and test certificates <strong>of</strong> materials used are<br />
submitted by the contractor and must <strong>in</strong>clude all QA certification. These must show conformance with<br />
the specification. <strong>Pipe</strong> preparation consists <strong>of</strong> clean<strong>in</strong>g by jett<strong>in</strong>g, a CCTV survey, and root removal if<br />
necessary. This is done by the contractor under the rehabilitation contract and is considered essential to<br />
ensure a good quality <strong>in</strong>stallation. Site supervision consists <strong>of</strong> monitor<strong>in</strong>g <strong>of</strong> <strong>in</strong>stallation, the<br />
cur<strong>in</strong>g/cool<strong>in</strong>g cycle and any re<strong>in</strong>statement works and is undertaken by a third party project manager.<br />
Copies <strong>of</strong> all control documents are obta<strong>in</strong>ed as part <strong>of</strong> the QA process. No process verification test<br />
samples are taken. CAC is consider<strong>in</strong>g add<strong>in</strong>g this to the specification so that mechanical test<strong>in</strong>g is<br />
undertaken. A post-<strong>in</strong>stallation CCTV survey is required and is required to be repeated after one year at<br />
the end <strong>of</strong> the warranty period, but this second <strong>in</strong>spection is not <strong>of</strong>ten done.<br />
Few problems are encountered. The ma<strong>in</strong> ones concern poor reopen<strong>in</strong>g <strong>of</strong> lateral connections.<br />
Occasional partial collapse <strong>of</strong> l<strong>in</strong>ers has also occurred. Lack <strong>of</strong> adhesion to the host pipe, especially at<br />
manholes is a common problem, and grout <strong>in</strong>jection is used to rectify this.<br />
CAC uses CIPP to re<strong>in</strong>force sewers where there is high risk <strong>of</strong> root penetration. For structural problems,<br />
and even I/I, open cut replacement with ductile iron pipe is preferred. The condition <strong>of</strong> lateral<br />
connections and frequent displaced pipes means that CIPP is considered <strong>in</strong>effective <strong>in</strong> combat<strong>in</strong>g I/I.<br />
CIPP is considered a ma<strong>in</strong>tenance activity rather than capital expenditure/asset renewal. Nevertheless<br />
CAC expects to <strong>in</strong>crease its usage <strong>of</strong> CIPP <strong>in</strong> the com<strong>in</strong>g years, and to <strong>in</strong>crease rehabilitation at the<br />
expense <strong>of</strong> replacement <strong>in</strong> order to improve the network with<strong>in</strong> its limited budget.<br />
C.4 Communauté d'Agglomeration Les Hauts-de-Bièvre (CAHB)<br />
CAHB was <strong>in</strong>terviewed <strong>in</strong> Paris on October 19, 2010. The <strong>in</strong>terview was conducted <strong>in</strong> French with the<br />
head <strong>of</strong> the water and wastewater service. CAHB comb<strong>in</strong>es several local authorities <strong>in</strong> the southwestern<br />
suburbs <strong>of</strong> Paris, <strong>in</strong>clud<strong>in</strong>g Versailles. The population served is approximately 100,000. The collection<br />
system is both separate and comb<strong>in</strong>ed, with a total ma<strong>in</strong>s length <strong>of</strong> 450 km (280 mi) and approximately<br />
25,000 lateral connections.<br />
CAHB first used CIPP <strong>in</strong> 1996 when Insituform was used. The total <strong>in</strong>stallation s<strong>in</strong>ce then is<br />
approximately 30 km (18.6 mi) <strong>in</strong> diameters from 200 to 500 mm (8 to 20 <strong>in</strong>.). Current <strong>in</strong>stallation is<br />
approximately 3 km (1.9 mi) per year, and this level is expected to rema<strong>in</strong> unchanged <strong>in</strong> the com<strong>in</strong>g<br />
years. Most projects are quite small, less than 200 m (656 ft) <strong>in</strong> length, and there are up to 20 such<br />
<strong>in</strong>stallations per year. Other rehabilitation methods used are open cut replacement, pipe burst<strong>in</strong>g and<br />
replacement with PVC when upsiz<strong>in</strong>g is necessary, and robotic local repairs at junctions with lateral<br />
connections. Almost all <strong>of</strong> the CIPP <strong>in</strong>stalled is full length from manhole to manhole. CAHB has used<br />
short patch l<strong>in</strong>ers but experience was poor and they are no longer used. No specific technical reason was<br />
given, but fund<strong>in</strong>g may be a reason. The Agences d’Eau (government water agencies) that are the source<br />
<strong>of</strong> funds for local operators do not fund short l<strong>in</strong>er works as they are considered to be repairs and not<br />
renovation. For renovation, they will fund up to 40% <strong>of</strong> the cost.<br />
Some 3 to 5 km (1.9 to 3.1 mi) <strong>of</strong> lateral l<strong>in</strong><strong>in</strong>g has been used, all <strong>in</strong>stalled from man-entry size sewers<br />
rather than remotely. This is considered successful and CAHB expects to <strong>in</strong>crease its usage <strong>of</strong> this<br />
C-9