Code of Maine Rules › 06 - DEPARTMENT OF ENVIRONMENTAL PROTECTION › 096 - DEPARTMENT OF ENVIRONMENTAL PROTECTION - GENERAL › Chapter 691 - RULE FOR UNDERGROUND OIL STORAGE FACILITIES › Appendix 096-691-A - Requirements for Cathodic Protection Monitoring

Current through 2024-29, July 17, 2024
1.
For Galvanic Cathodic Protection
				  Systems
A. All measurements must be made by placing a saturated
				  copper/copper sulfate reference electrode in direct contact with the soil
				  electrolyte.
B. The copper/copper sulfate electrode must be placed over
				  the center line of each tank and within 1 foot of each piping run. For
				  single-walled tanks a minimum of three (3) measurements are to be made over the
				  center line of each tank, one at each end and one at the tank's midpoint. For
				  double-walled tanks, a minimum of one voltage measurement over each tank's
				  midpoint is required.
C. All measurements must be recorded using a direct current
				  voltage measuring device with a minimum of 10 megohms input impedance, accurate
				  to at least + 1 percentat 1 volt.
D. A measurement of at least negative 0.85 volts must be
				  recorded for each test location and each metallic facility component, including
				  tanks, piping, and connectors that are cathodically protected.
E. When a negative voltage of at least 0.85 volts is not
				  achieved upon installation of the tank or piping, the measurement must be
				  repeated within 6 months. Upon failing to achieve a negative voltage of at
				  least negative 0.85 volts after the 6-month period, the tank owner shall comply
				  with paragraph F, below.
F. The tank owner shall repair or replace the system in
				  accordance with the recommendations of the National Association of Corrosion
				  Engineers, Standard Practice 0285-or STI Recommended Practice for the Addition
				  of Supplemental Anodes to STI-P3® USTs, R972 and section
				  5(D)(14) of this
				  Chapter whenever the system does not register a negative voltage reading of at
				  least 0.85 volts for each tank or piping run within six (6) months of the first
				  failed measurement, or properly abandon in accordance with section
				  11, except as provided for in
				  paragraph E for a new installation.
G. The frequency of cathodic protection monitoring must be
				  consistent with the requirements outlined in section
				  5(D)(3) and
				  (4).
H. A cathodically protected steel tank or piping that
				  continues to fail to achieve the minimum level of adequate corrosion protection
				  of at least 0.85 volts within six (6) months of repair or replacement in
				  accordance with paragraph F shall be properly abandoned in accordance with
				  section
				  11.
2.
For Impressed Current or Galvanic Cathodic
				  Protection Systems
Test methods and criteria as described in the NACE TM 0101,
				  Measurement Techniques Related to Criteria for Cathodic Protection on
				  Underground or Submerged Metallic Tank Systems, or TM 0497, Measurement
				  Techniques Related to Criteria for Cathodic Protection on Underground or
				  Submerged Metallic Piping Systems, are to be used to monitor impressed current
				  systems. These methods for testing galvanic systems may be used with prior
				  written approval of the Commissioner.
NOTE: Structure to soil potentials measured when the soil is
				  frozen may be inaccurate because of the increased resistance of the soil
				  electrolyte. Cathodic protection monitoring schedules should be planned to
				  avoid frozen soil conditions.