Attachment 06 Cathodic Protection Report.pdf

This is a cathodic protection inspection report for Tank 1617 and associated piping at Shaw Air Force Base. The report details a 250,000-gallon non-potable water storage tank (Tank 1617) constructed in 1959 by Richmond Engineering Company, with dimensions of 37-feet inner diameter and 32-feet height, connected to Pumphouse B1616 via six pipes ranging from 6" to 18" in diameter.

The tank has two Impressed Current Cathodic Protection (ICCP) systems, with this report focusing on the external system installed in 2008. Testing revealed the system is operating at 8.4-volts and 0.129-amps with a groundbed resistance of 65.1-ohms. The report indicates that polarized potentials did not meet NACE -850 mV criteria at most test points, ranging between -200 mVCSE and -500 mVCSE. The report recommends installing additional anode groundbed capacity between Tank 1617 and B1616, including an anode junction box near the rectifier, due to insufficient corrosion protection in this area. The 15-year-old anodes and high groundbed resistance of 65-ohms are contributing factors to the inadequate protection levels.