Trenchless Technology

OCT 2018

Trenchless Technology is the premier communications vehicle for the trenchless industry. Through our multiple platforms, readers receive insights into the trenchless industry, as well as keep connected to the latest news, products and projects.

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84 T R E N C H L E S S T EC H N O LO GY O C TO B E R 2018 N A S S C O R E P O R T : I N F R A S T R U C T U R E A S S E S S M E N T C O M M I T T E E THE USE OF CLOSE CIRCUIT TELE- VISION (CCTV) inspection technology is critical to the successful completion of cured-in-place pipe (CIPP) projects. Sewer mains destined for rehabilita- tion using CIPP are usually inspected multiple times prior to, during and af- ter installation. These inspections help to determine design parameters, pipe preparation and remedial works for ac- ceptance purposes in addition to the placement and installation of the liner. This article provides guidance when in- spection is necessary at every stage of CIPP installation. Despite the need for rigorous inspections, not every stage requires Pipeline Assessment Certi ication Program (PACP) defect coding; some inspections will be used as a means for determining readiness and acceptance versus documentation of pipe condition. Defect coding is typically only necessary during the post-lining and warranty inspection phases of the work and is meant to serve as the current and inal condition / benchmark of the sewer line. Where required, the speci ications should state when NASSCO PACP coding should be produced and submitted. A sewer segment placed into a prioritized rehabilitation work program will almost certainly have historical inspection data available. Where available, this information may be used to determine CIPP applicability, external point repairs, pre-lining sewer preparation, and CIPP design parameters. Additional inspection should be undertaken when CCTV inspection data is not available, out of date, or where deterioration is known to be progressive. Historical CCTV information should be made available to contractors during the bid period. In addition to the inspections noted below, contractors utilize CCTV inspection technology throughout the CIPP installation process to facilitate cleaning , debris cutting and removal, and service reinstatement. Pre-Lining Inspections Inspection prior to lining is critical to ensure the sewer has been adequately prepared for lining and to con irm the CIPP design parameters utilized in design. For larger circular sewers (36in. or greater) or non-circular sewers, a pre-design inspection may be necessary to con irm the internal dimensions of the host pipe prior to design at a given frequency, usually every 15 lf. These values are used after installation to con irm the close it nature of the CIPP. Coding is not typically required. An inspection should be completed after cleaning and preparation of the sewer while low control measurements are in place. The intent of this inspection is to provide evidence that the sewer was adequately cleaned and prepared just prior to the installation of the liner. Coding is not typically required. Post-Lining Inspections A post-installation inspection should be completed immediately following the installation of the liner and after the completion of sewer service reinstatement while low control measurements are still in place. This will con irm the adequacy of the CIPP, showing both the invert and service reinstatements that would also provide good evidence of the it and inish of the CIPP. Full NASSCO PACP coding or similar would be submitted to the Inspector and client as a potential inal inspection. Again, for large circular or non-circular liner installations, it is recommended that further inspection be performed to confirm the new interior dimensions, at the same distance frequency of 15 lineal feet of the CIPP. The intent is to confirm the close fit nature of the finished product and identify locations with an annulus or other defects requiring repairs or remedial work prior to final acceptance. Coding of this inspection is not typically required. Warranty inspections are critical to ensure the long- term performance of the CIPP. All (or a section) of the CIPP within the contract will be selected for inspection prior to the expiration of the warranty period. Any defects identi ied during the warranty inspection process will be recti ied by the Contractor prior to inal acceptance of the work. NASSCO PACP coding should be provided. This article was provided by Chris Mitchell, PACP Trainer and Member of NASSCO's Infrastructure Assessment Committee. T h e I m p o r ta n c e o f M u lt i p l e I n s p e c t i o n s d u r i n g C I P P R e h a b i l i tat i o n B y C h r i s M i t c h e l l The use of CCTV inspection technology is critical to the successful completion of CIPP projects. Sewer mains destined for rehab using CIPP are usually inspected multiple times prior to, during and after installation.

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