Chapter ATCP 93

ATCP 93.520(1)(a) (a) Where required. Vent lines, vapor lines and any portion of a single or double-wall tank system, whether new or existing, that routinely contains product and is in contact with the ground or with water shall be protected from corrosion by one of the following methods:

ATCP 93.520(1)(a)1. 1. The tank and piping are constructed of an inherently corrosion-resistant material.

ATCP 93.520(1)(a)2. 2.

ATCP 93.520(1)(a)2.a. a. The tank and piping are installed at a site that is determined by a certified corrosion expert to be non-corrosive during the operational life of the system.

ATCP 93.520(1)(a)2.b. b. A certified corrosion expert retained for the purpose of determining a non-corrosive site shall make at least one personal visit to each tank site during the design stage.

ATCP 93.520 Note Note: See ATCP Table 93.200–5 for information on contacting NACE.

ATCP 93.520(1)(a)3. 3. The tank is a listed composite or jacketed tank designated as complying with UL 1746, and the piping is protected by one of the methods in this subsection.

ATCP 93.520 Note Note: In addition to composite and jacketed tanks, the UL 1746 standard also includes requirements for coated tanks and tanks with pre-engineered cathodic protection systems. These last 2 types of cathodic protection are not included in the blanket approval under this section.

ATCP 93.520(1)(a)4. 4. The tank and piping are protected with a sacrificial anode system in accordance with a standard developed by a nationally recognized association or independent testing laboratory that is acceptable to the department.

ATCP 93.520(1)(a)5. 5.

ATCP 93.520(1)(a)5.a. a. The tank and piping are protected with a corrosion protection system designed by a certified corrosion expert and comply with either sub. (2) or (3).

ATCP 93.520(1)(a)5.b. b. A corrosion expert retained for the purpose of designing an impressed current corrosion protections system shall make at least one personal visit to each tank site during the design stage.

ATCP 93.520(1)(b) (b) Design and construction.

ATCP 93.520(1)(b)1. 1. To allow for periodic testing, new and replacement factory- or field-installed corrosion protection systems shall have appropriate connections, insulated lead wires and accessible test stations, including as specified in subds. 2. and 3.

ATCP 93.520(1)(b)2. 2. All lead wires connected to a tank, anode, reference electrode, or other component associated with the corrosion protection system shall terminate at a test station.

ATCP 93.520(1)(b)3. 3. The termination of each lead wire at a test station shall be clearly labeled or coded to identify the specific component to which it is connected.

ATCP 93.520(1)(b)4. 4. Impressed current systems shall be designed to prevent stray current conditions that may negatively impact other underground structures, utility lines, or cable anchors, or any impressed current systems protecting those items.

ATCP 93.520(1)(b)5. 5. Local utilities shall be notified by the contractor when impressed current systems are installed, repaired, or adjusted, including where an increase in rectifier amperage or voltage output occurs.

ATCP 93.520(1)(c) (c) Operation and maintenance.

ATCP 93.520(1)(c)1. 1. Operation and maintenance of corrosion protection systems shall be in accordance with national standards acceptable to the department.

ATCP 93.520(1)(c)2. 2. All new and existing corrosion protection systems shall be operated and maintained to continuously provide corrosion protection for the life of the tank system.

ATCP 93.520(1)(c)3. 3. For impressed current systems, operation and maintenance practices and procedures shall be evaluated, and conducted in a manner that minimizes direct current interference to or from any underground structure, utility line, or cable anchors in the area.

ATCP 93.520(1)(d) (d) Periodic testing requirements.

ATCP 93.520(1)(d)1. 1.

ATCP 93.520(1)(d)1.a. a. All new and existing corrosion protection for UST systems shall be tested within 6 months of installation or repair and at least annually, except as provided in subd. 3.

ATCP 93.520(1)(d)1.b. b. For sacrificial anode systems, structure-to-soil potential readings shall be conducted with a minimum of one local potential measurement near the UST center and away from the anodes and one remote potential measurement. Alternatively, a minimum of three potential measurements, one at each of the UST ends and one near the center of the UST, may be taken.

ATCP 93.520 Note Note: This requirement is from NACE standard TM-0101.

ATCP 93.520(1)(d)1.bm. bm. For impressed current systems, structure-to-soil potential readings shall be conducted with a minimum of three potential measurements, one at each of the UST ends and one near the center of the UST.

ATCP 93.520 Note Note: This requirement is from NACE standard TM-0101.

ATCP 93.520(1)(d)1.c. c. For each product line, structure-to-soil potentials shall be taken above the piping, at the ends and middle, away from the anode locations. Piping runs over 50 feet shall have additional readings taken every 25 feet.

ATCP 93.520(1)(d)1.d. d. For impressed current systems, the annual test shall include instant-off potentials.

ATCP 93.520(1)(d)2. 2. In addition to the requirements in subd. 1., impressed current corrosion protection systems shall be inspected and evaluated by the site operator at least every 60 days to ensure the equipment is providing adequate current in accordance with its design.

ATCP 93.520(1)(d)3. 3. Tanks designated as sti-P3Ò equipped with a preinstalled sacrificial anode system and test station shall be tested in accordance with all of the following:

ATCP 93.520(1)(d)3.a. a. Testing shall occur within 6 months of installation and at least every 3 years thereafter until the tank is 10 years old.

ATCP 93.520(1)(d)3.b. b. Testing shall occur annually in accordance with subd. 1. after the tank is 10 years old.

ATCP 93.520(1)(d)4. 4. The results of the inspections, evaluations and testing under this paragraph shall be summarized on the department’s form, TR-WM-141, and retained at the site in accordance with s. ATCP 93.500 (9).

ATCP 93.520 Note Note: Form TR-WM-141, UST Corrosion Protection Test/Survey Report, is available from the Bureau of Weights and Measures, PO Box 8911, Madison, WI 53708-8911, or at telephone [phone], or from the Bureau’s Web site at https://datcp.wi.gov/Pages/Programs_Services/PetroleumHazStorageTanks.aspx.

ATCP 93.520 Note Note: Section ATCP 93.500 (9) specifies retention requirements for testing and repair records of corrosion protection systems.

ATCP 93.520(1)(e) (e) Certifications for corrosion protection.

ATCP 93.520(1)(e)1. 1. A certified cathodic protection tester shall be on the site to supervise and monitor the initial post-installation start-up of impressed current corrosion protection systems.

ATCP 93.520 Note Note: NACE requires a person with Senior Corrosion Technologist certification or higher for corrosion protection system commissioning.

ATCP 93.520(1)(e)2. 2. A certified cathodic protection tester shall perform or supervise the performance of reinstallation or replacement of anodes.

ATCP 93.520 Note Note: NACE requires a person with Level 1 Cathodic Protection Tester certification or higher for reinstallation or replacement of anodes.

ATCP 93.520(1)(e)3. 3.

ATCP 93.520(1)(e)3.a. a. All new and existing corrosion protection for UST systems shall be tested by a certified cathodic protection tester, except as provided in subd. 3. b.

ATCP 93.520 Note Note: NACE requires a person with corrosion technologist certification or higher or a person with corrosion technician certification who is directly supervised by a certified corrosion technologist or higher to perform work as a state-certified cathodic protection tester.

ATCP 93.520(1)(e)3.b. b. Tanks designated as sti-P3Ò shall be tested by a person holding a certification from the Steel Tank Institute or one of the certifications in subd. 3. a.

ATCP 93.520 Note Note: Additional information on corrosion protection certifications is available from the department’s Web site at https://datcp.wi.gov/Pages/Programs_Services/PetroleumHazStorageTanks.aspx.

ATCP 93.520(2) (2) Sacrificial anode systems.

ATCP 93.520(2)(a) (a) General. All new and existing sacrificial anode systems shall maintain the standard protection threshold reading of at least negative 850 millivolts or shall comply with the requirements of par. (b).

ATCP 93.520(2)(b) (b) Failing sacrificial anode systems.

ATCP 93.520(2)(b)1. 1. Unless arrangements are made with the authorized agent or the department to conduct follow-up testing, the cause of the failure shall be investigated and repaired within 90 days of the failed reading; or the entire tank system shall be emptied within 90 days of the failed reading and shall remain empty until the repair is completed.

ATCP 93.520(2)(b)2. 2. If more than 2 years have elapsed since the previous corrosion protection test, or if the corrosion protection system has been inoperative for 2 years or more, an internal inspection shall be performed by a third party in accordance with one of the following standards:

ATCP 93.520(2)(b)2.a. a. For lined tanks, the internal inspection shall be in accordance with API 1631 or KWA.

ATCP 93.520(2)(b)2.b. b. For unlined tanks, the internal inspection shall be in accordance with ASTM G158 Method B.

ATCP 93.520(2)(b)3. 3. If the tank fails the internal inspection, one of the following shall occur:

ATCP 93.520(2)(b)3.a. a. The tank system shall be permanently closed.

ATCP 93.520(2)(b)3.b. b. The tank system shall be lined or any present lining shall be repaired in accordance with API 1631, and an impressed current corrosion protection system shall be installed.

ATCP 93.520(2)(b)4. 4. After an inspection under this paragraph, if the tank is not closed under subd. 3. a., a precision tightness test shall be performed on the tank system in accordance with s. ATCP 93.515 (4). In addition, a tightness test shall be performed on the ullage portion of the tank in accordance with s. ATCP 93.515 (10).

ATCP 93.520(3) (3) Impressed current systems.

ATCP 93.520(3)(a) (a) General.

ATCP 93.520(3)(a)1. 1. Equipment for impressed current systems shall be served by a dedicated and clearly marked electrical circuit that remains energized at all times.

ATCP 93.520(3)(a)2. 2. All new and existing impressed current systems shall maintain either of the following standard protection levels:

ATCP 93.520(3)(a)2.a. a. An instant-off reading of at least negative 850 millivolts.

ATCP 93.520(3)(a)2.b. b. A 100 millivolt or greater negative shift in polarization between the instant-off reading and the native soil reading or a 100 millivolt or greater positive shift in the depolarized structure potential from the instant-off reading.

ATCP 93.520(3)(a)3. 3. When a new impressed current system is installed or an existing system is replaced in whole or in part, an ammeter shall be installed, along with an hour meter that totals the number of hours during which electric current flows through the system.

ATCP 93.520(3)(b) (b) Failing impressed current systems. If impressed current corrosion protection readings taken in accordance with sub. (1) (d) 2. indicate the system is not maintaining adequate continuous protection, the system shall be analyzed by a certified corrosion expert for site corrosion potential and qualification of system functionality.

ATCP 93.520(3)(c) (c) Inoperative impressed current systems.

ATCP 93.520(3)(c)1. 1. Impressed current systems that have been inoperative for 120 days or less shall comply with all of the following requirements:

ATCP 93.520(3)(c)1.a. a. Power shall be restored and the system shall be tested by a certified cathodic protection tester for system functionality.

ATCP 93.520(3)(c)1.b. b. If the impressed current system is damaged or inoperable, a certified corrosion expert shall repair, survey, and recommission the system.

ATCP 93.520(3)(c)2. 2. Impressed current systems that have been inoperative for 121 to 180 days shall comply with all of the following requirements:

ATCP 93.520(3)(c)2.a. a. A precision tightness test shall be performed on the tank system in accordance with s. ATCP 93.515 (4) within 15 days of discovery.

ATCP 93.520(3)(c)2.b. b. Power shall be restored and the system shall be tested for system functionality by a certified cathodic protection tester.

ATCP 93.520(3)(c)2.c. c. If the impressed current system is damaged or inoperable, a certified corrosion expert shall repair, survey, and recommission the system.

ATCP 93.520(3)(c)3. 3. Impressed current systems that have been inoperative for 181 to 365 days shall comply with all of the following requirements:

ATCP 93.520(3)(c)3.a. a. A precision tightness test shall be performed on the tank system in accordance with s. ATCP 93.515 (4) within 15 days of discovery.

ATCP 93.520(3)(c)3.b. b. A certified corrosion expert shall assess, survey, and recommission the impressed current system and perform any necessary repairs.

ATCP 93.520(3)(c)4. 4. Impressed current systems that have been either inoperative or not tested for more than 365 days shall comply with all of the following requirements:

ATCP 93.520(3)(c)4.a. a. An internal inspection of the tank shall be performed in accordance with sub. (2) (b) 2.

ATCP 93.520(3)(c)4.b. b. If the tank fails the internal inspection, the tank owner shall either have the tank repaired and lined, or have the lining repaired in accordance with s. ATCP 93.530, or have the tank permanently closed and removed in accordance with s. ATCP 93.560.

ATCP 93.520(3)(c)4.c. c. If the tank is not closed under subd. 4. b., a certified corrosion expert shall assess, survey, and re-commission the impressed current system and perform any necessary repairs.

ATCP 93.520(3)(c)4.d. d. If the tank is not closed under subd. 4. b., a precision tightness test shall be performed on the tank system in accordance with s. ATCP 93.515 (4). In addition, a tightness test shall be performed on the ullage portion of the tank in accordance with s. ATCP 93.515 (10).

ATCP 93.520 History History: CR 17-092: cr. Register October 2019 No. 766, eff. 11-1-19; correction in (1) (d) 3. (intro.), (e) 3., (2) (b) 2., (3) (c) 4. c., d. made under s. 35.17, Stats., Register October 2019 No. 766.

ATCP 93.530 ATCP 93.530 Tank lining of underground storage tanks.

ATCP 93.530(1) (1) General.

ATCP 93.530(1)(a) (a) The installation of interior tank lining for underground storage tanks shall comply with API 1631 and this section.

ATCP 93.530(1)(b) (b) An underground storage tank that does not meet the structural requirements specified in API 1631 may not be upgraded or repaired by lining and shall be permanently closed in accordance with this chapter.

ATCP 93.530(1)(c) (c) When lining a tank, an access way for an inspector to enter the tank shall be installed from the tank interior to finished grade, if not already provided.