Attachment 06 Cathodic Protection Report.pdf

This is a cathodic protection inspection report and documentation for Tank 1617 and its associated piping to Pumphouse B1616 at Shaw Air Force Base. The report details a 250,000-gallon non-potable water storage tank constructed in 1959 by Richmond Engineering Company, with dimensions of 37-feet inner diameter and 32-feet height. The tank has two impressed current cathodic protection (ICCP) systems - one for the external tank bottom and buried piping, and another for internal surfaces.

The inspection found that the external ICCP system, installed in 2008, was operating at 8.4-volts and 0.129-amps with a groundbed resistance of 65.1-ohms. While the rectifier was functioning properly, the system did not meet NACE International's -850mV polarization criterion due to dissimilar metals, with potentials ranging between -200mV and -500mV. The report recommends installing additional anode groundbed capacity between Tank 1617 and B1616, including an anode junction box near the rectifier, as the current anode configuration fails to adequately protect the area between the tank and pumphouse where buried piping is routed. The inspection was conducted in March 2023 and includes detailed testing data, photographs, and system drawings.