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 11-5-2-280.1-6.10 - Cathodic Protection Test Locations
Section 11-5-2-280.1-6.10.1 - Galvanically Protected (sti-P3*) Tanks
The measurement of both local and remote structure-to-soil potentials is necessary when evaluating sti-P3 tanks. The appropriate location to place the reference electrode locally would be in the soil at the middle of the tank (see Figure 3). However, if access to the soil is not available at the middle of the tank, the reference electrode may be placed at any point along the centerline of the tank but not directly over the anodes at each end of the tank.
Caution should be exercised to ensure that there are no sacrificial anodes installed in the soil around the submersible pump manway to protect any steel piping that may be associated with the tank. If anodes are installed at the pump manway, the reference electrode must be placed in the soil near the opposite end of the tank.
In addition to the local potential described above, a remote potential must also be obtained. Remote generally means the reference electrode is placed in the soil at least 25 feet away and not more than 100 feet away from the tank you are measuring (See Figure 4). Refer to Section 6.8.3 for a more complete discussion of remote reference electrode placement. Care must be taken that the remote location is not in proximity to any other cathodically protected structure (e.g. natural gas lines) or directly over any other kind of buried metallic structure. The remote placement should be such that the reference electrode is aligned with the longitudinal axis of the tanks and can "see" the anodes. This orientation is desirable in order to prevent shielding.
