Mississippi Administrative Code
Title 11 - Mississippi Department of Environmental Quality
Part 5 - Underground Storage Tank Regulations
Chapter 2 - Mississippi Commission on Environmental Quality Underground Storage Tanks Regulations Technical Standards and Corrective Action Requirements for Owners and Operators of Underground Storage Tanks (UST) (Adopted March 22, 1989; Amended August 25, 2011, Last Amended August 23, 2018)
Appendix 11-5-2-280.1 - GUIDELINES FOR THE EVALUATION OF UNDERGROUND STORAGE TANK CATHODIC PROTECTION SYSTEMS
Section 11-5-2-280.1-6 - CATHODIC PROTECTION TESTING
Section 11-5-2-280.1-6.8 - Reference Electrode Placement
Section 11-5-2-280.1-6.8.5 - Impressed Current Placement
Impressed current cathodic protection systems are only required to be tested with the reference electrode placed locally. In order to pass the survey, the potential obtained with the reference electrode placed locally must satisfy either the 850 off or the 100 mV polarization criteria. While only one test point is required, the tester should obtain structure to soil potentials from as manysoil access points along the structure as is practical. If any of the potentials indicate that adequate cathodic protection has not been provided, the structure should be failed. Although not required by this guidance, it may be useful to place the reference electrode remotely when testing an impressed current system. The remote potential may provide additional information by which to evaluate the cathodic protection system. However, the structure may not be passed based on the remote potential itself. In all circumstances, the potential obtained with the reference electrode placed locally must indicate that adequate cathodic protection has been provided.
Additionally, special circumstances may require that a remote potential be obtained when testing impressed current systems. For instance, if there are active sacrificial anodes buried in close proximity to the structure being tested, the local potential may be influenced by raised earth. The voltage drop caused by the sacrificial anodes would preclude the accurate measurement of the local structure-to-soil potential. If it is known that sacrificial anodes are impacting the potentials obtained locally, remote potentials must be obtained.
The remote potential obtained under these special circumstances must meet either the 850 off or the 100 mV polarization criteria in order for the tested structure to pass the survey. An explanation must be given in the "comments" of Section XVI of the MDEQ impressed current cathodic protection evaluation form as to why the remote potential must be considered. The remote potentials should be indicated on the form by designating remote in the location code column of Section XVI.
