CP Retrofit of shallow pipeline in swamp

Retrofit of shallow pipeline in swamp with RetroLinks™ and RetroClamps™

Deepwater Corrosion Services was contracted by Boardwalk Pipeline to provide cathodic protection (CP) retrofit materials and installation supervision for their 12” pipeline Index 201 after finding low CP readings on the pipeline in 2 locations.

A CP survey was performed at the locations where a previous survey found low CP levels. The pre-retrofit CP readings from the two locations were found to be -0.607V and-0.660V vs Copper/CopperSulfate (CCS).

Deepwater installed a total of 490 feet of RetroLink™ anode strings in 2 locations on the pipeline where the low readings were found.

A Deepwater technician supervised a construction crew as they installed two RetroClamps™ onto the 12” pipeline. The RetroClamps™ were installed with the use of a Deepwater RetroReader™, a piece of electronic CP monitoring equipment that provides a signal when the RetroClamp™ has made electrical contact to the pipe and is permanently installed. Both RetroClamps™ were installed onto the pipeline and anode grounding cables that were attached to the RetroClamp™ were connected to the topside junction box.

Two zinc RetroLinks™ were installed at each RetroClamp™ location and laid out on the bottom of the swamp next to the pipeline. Two grounding cables connected to each RetroLink™ were routed and connected into the topside junction box. The electrical grounding connection between the anodes and pipeline are made in the topside junction box so that off-potential (anode free) CP measurements can be taken on the pipeline.

After the installation was complete, a CP survey at the junction box showed readings from the two locations were -0.973V and -0.860V vs Copper/CopperSulfate (CCS).

Both RetroClamps™ and all four RetroLinks™ were installed in one day. The post-retrofit CP survey shows a negative polarization shift indicating the anodes are electrically grounded to the pipeline and are providing cathodic protection current.

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