Section 170.460  Corrosion Protection

 

a)         Cathodic Protection.  A tank may be upgraded by cathodic protection if the cathodic protection system meets the requirements of this Part, and the integrity of the tank is ensured using one of the following methods:

 

1)         To be suitable for upgrading by cathodic protection, the integrity of the tank must be ensured by one of the following methods:

 

A)        For tanks installed for less than 10 years, the following methods apply:

 

i)          The tank is internally inspected and assessed to ensure that the tank is structurally sound and free of corrosion holes prior to installing the cathodic protection system;

 

ii)         The tank is monitored monthly for releases using a permanent method of leak detection as approved by OSFM.  Monthly inventory control, manual tank gauging and SIR do not meet this requirement;

 

iii)         Two tank precision tests must be conducted that meet the requirements of OSFM precision tank tightness testing.  The first precision test shall be conducted prior to the installation of the cathodic protection system.  The second precision test shall be conducted between 3 and 6 months following the first operation of the installed cathodic protection system.  Both tests must indicate tightness of the tanks;

 

iv)        Use of approved alternate methods approved by OSFM.  These acceptable alternate methods are indicated in subsection (a)(1)(B) for tanks that are over 10 years old.

 

B)        For tanks installed for more than 10 years, the following methods apply:

 

i)          An invasive inspection method that ensures the tank is internally inspected and assessed to ensure that the tank is structurally sound and free of corrosion holes prior to installing the cathodic system.  The internal inspection procedures shall meet the requirements of NLPA 631, 1991 edition, Internal Inspection of Steel Tanks for Retrofit of Cathodic Protection. This standard for interior lining meets this requirement.

 

ii)         An invasive remote video camera test is conducted prior to the installation of the cathodic protection system.  The video system must be capable of recording a video survey of the interior surface of the tank with a suitable lighting source.

 

iii)         A non-invasive tank life/corrosion model test is conducted to examine the soil environment in the immediate vicinity of the tank and the relationship of the metal UST to this environment.  A statistical model is used to assess the relationship between the aggressiveness of the environment and the rate of corrosion and to predict the remaining life of the UST prior to corrosion failure.  Some examples of non-invasive methods are Mean Time to Corrosion Failure (MTCF) and International Lubrication and Fuel Consultants (ILFC).

 

iv)        The tanks are assessed for corrosion holes by other methods determined by OSFM, to prevent releases in a manner that is no less protective of human health and the environment than subsections (a)(1)(B)(i), (ii) and (iii).

 

2)         OSFM requires a tank integrity assessment even if both cathodic protection and interior lining systems are being installed.  If the cathodic protection and interior lining are installed at the same time, only one approved integrity assessment is required.  Even if both systems have been installed, OSFM requires routine inspection and maintenance of both systems to continue.

 

3)         In all situations, no matter which method is used to assess the integrity of the tank prior to addition of cathodic protection, the cathodic protection system being field installed in Illinois must be designed by a NACE certified corrosion expert.  Those contractors installing the cathodic protection systems in Illinois must be licensed as cathodic protection installers.  These contractors must successfully pass the International Code Council (ICC) certification exam module for cathodic protection.

 

4)         If one of the non-invasive methods described in this Section has been used to assess tank integrity of a tank older than 10 years, the leak detection method used on these tanks after installing the cathodic protection system may not be either the monthly inventory control method, SIR, or manual tank gauging method of leak detection.  Acceptable leak detection methods that can be used are as follows:  automatic tank gauging, vapor monitoring, groundwater monitoring, interstitial monitoring, fiber optics or tracer elements.

 

5)         For UST systems equipped with both interior lining and cathodic protection (sacrificial anodes or impressed current), the following maintenance procedures shall apply:

 

A)        For those UST systems that have documentation, including original field notes from the initial lining, of an invasive method of initial tank integrity assessment that verifies that there were no holes in the tank, only the external cathodic protection system must be maintained and tested.

 

i)          Sacrificial anodes must be tested every 3 years and records kept on site for 3 years.

 

ii)         Impressed current records of operation must be recorded every 30 days and records kept on site for 3 years. The system must be tested yearly and records kept on site for 3 years.

 

iii)         In the event that a reading of -875 millivolts or less is recorded, with testing being conducted above the structure, on any type of corrosion protection system, then yearly testing will be required thereafter. In the event that upgrading of the cathodic protection system results in readings greater than -875 millivolts with readings being conducted above the structure, then testing may be conducted every 3 years, unless the 6 month test after upgrading produces a reading of -875 millivolts or less, then yearly testing will be required thereafter.

 

B)        For those UST systems where a non-invasive tank integrity assessment method was used or if there were any holes present in the tank, the interior lining must be maintained and inspected as described in OSFM lining requirements.

 

C)        Nothing prohibits the maintenance of both systems.

 

D)        Owners of UST systems with both interior lining and cathodic protection must submit a UST notification form and declare what system they intend to maintain.

 

b)         ACT-100 Tanks.  Tank owners with these types of tanks may choose to use either type of protection on the tank.  However, the tank owner must be able to produce ACT-100 warranty papers to prove that they actually do have ACT-100 tanks.

 

c)         Internal lining combined with cathodic protection.  A tank may be upgraded by both internal lining and cathodic protection if:

 

1)         The lining is installed in accordance with the requirements of Section 170.430; and

 

2)         The cathodic protection system meets the requirements of Section 170.420(a)(2)(B) through (D).  (The following codes and standards, incorporated by reference in Section 170.410, may be used to comply with this Section: API Recommended Practice 1631; NLPA Standard 631; NACE RPO285; or API Recommended Practice 1632.)

 

An interior inspection for an installation of internal lining combined with cathodic protection is required only once, provided an interior inspection was performed in compliance with subsection (d)(1) or (d)(2) of this Section and if performed within 90 days of each other.

 

d)         Piping corrosion protection requirements.  All UST metal product piping that is in contact with backfill, ground or water shall be cathodically protected. All metal risers, vents and fills in contact with backfill, ground or water shall be dielectrically coated.  Shrink-wrap or boots are not acceptable as a form of cathodic protection in a water environment.

 

e)         When installing, upgrading, or repairing a cathodic protection system, the following steps shall be taken.

 

1)         Secure proper permitting and provide required Cathodic Protection Upgrade Job Schedule to the OSFM and obtain the stamped receipt.

 

2)         Conduct on-site inspection to ensure accuracy of approved site plans, drawings and actual equipment being installed.

 

3)         OSFM personnel must conduct a Time Certain inspection of the corrosion protection installation before backfilling.

 

4)         Wiring of all associated electrical equipment shall conform to NFPA 70.

 

A)        All wiring that is connected to any anode of an impressed current system shall be no less than No. 10 stranded, with jacketing that is suitable for direct burial and that is petroleum or hazard resistant (including but not limited to HMWPE). Such jacketing is to have a thickness sufficient to cause the wiring to have a diameter of at least ⁵/₁₆- inch. Systems existing prior to May 1, 2003 may remain.

 

B)        All wiring connected to any anode of a sacrificial anode system shall be suitable for direct burial and shall be petroleum and/or hazardous resistant.

 

C)        All structural lead wiring of any cathodic protection system shall be suitable for direct burial and shall be petroleum and/or hazard resistant.

 

D)        For installation of cathodic protection systems to existing facilities, anode wiring may be placed into pavement saw-cuts, provided that the following conditions are met:

 

i)          No part of the wiring is less than one inch below the finished pavement surface, and provided that the portion of the saw-cut groove above the wiring is filled with a combination of at least ⅜-inch of backerrod and at least ½- inch of self-leveling caulk suitable as a concrete filler.

 

ii)         Structure lead wiring of impressed current systems shall consist of at least 2 separate leads. Such leads running from the junction box or rectifier to the UST system structures must be in separate saw-cuts, jumpering from one UST system structure to the next. One lead shall connect to the first structure to be protected and continue on to all structures in the UST system. The second lead will connect to the last structure to be protected. Such loop is to ensure that if one lead were to become cut or disconnected, the other lead would ensure the continued connection of the UST system structures and the junction box or rectifier.

 

iii)         All wiring from anodes shall terminate and be identified (as to location per approved site plan), in strategically located junction boxes, placed in and around the protected field. This will facilitate the testing of each anode.

 

E)         For installation of cathodic protection systems to new facilities, all wiring running outside of manholes or sumps shall be located at least 12 inches below the finished grade, and installed in electrical PVC conduit approved for petroleum and/or hazardous installation. The conduit trenches shall be continuously marked with yellow plastic caution tape, and placed not less than 6 inches above the conduit.

 

5)         After all work has been completed and the system has been put into service, OSFM personnel may conduct a two-hour Time Certain final inspection on the corrosion protection system and the electrical system.

 

6)         The completed Notification of Underground Storage Tanks form shall be ready to present to the OSFM STSS during the final inspection.

 

f)          Operation and Maintenance of Cathodic Protection.  Owners or operators of steel UST systems with corrosion protection shall comply with the following requirements to ensure that releases due to corrosion are prevented for as long as the UST system is used to store regulated substances:

 

1)         All corrosion protection systems shall be operated and maintained to continuously provide corrosion protection to the metal components of that portion of the tank and piping that routinely contain regulated substances and are in contact with the ground, backfill or water.

 

2)         All UST systems equipped with sacrificial anode cathodic protection systems shall be tested and inspected for proper operation, when being put into operation, by a certified ICC cathodic protection tester, or OSFM approved tester, in accordance with the following requirements:

 

A)        Frequency.  All cathodic protection systems shall be re-tested no less than 24 weeks and no more than 28 weeks from the date of installation or repairs. All sacrificial anode systems shall be tested every 3 years by a certified ICC tester or OSFM approved tester.  In the event that a reading of -875 millivolts or less is recorded with testing being conducted above the structure, on any type of corrosion protection system, then yearly testing will be required thereafter.  In the event that upgrading of the cathodic protection system results with readings greater than -875 millivolts with readings being conducted above the structure, then testing may be conducted every 3 years, unless the 6 month test after upgrading produces a reading of -875 millivolts or less, then yearly testing will be required thereafter.

 

B)        Inspection criteria.  The criteria that are used to determine that cathodic protection is adequate as required by this subsection (b) shall be in accordance with NACE Standard Recommended Practice RP0169-96 and RP0285-95. Subject to the technical applicability of such criteria given actual site conditions, one or more of the following criteria shall apply for adequacy of cathodic protection.

 

i)          A negative (cathodic) potential of at least 850 millivolts with cathodic protection applied.  This potential is measured with respect to a saturated copper/copper sulfate reference electrode contacting the electrolyte.

 

ii)         A minimum 100 millivolt of cathodic polarization between the structure and a saturated copper/copper sulfate reference electrode contacting the electrolyte.  Such polarization shall be determined from the taking of a valid "instant-off" test, which, for each testing point, determines the voltage reading at the second drop in voltage following the interruption in cathodic protection being applied, and determines if such voltage reading is at least 100 millivolts higher than either the native reading or any other reading after the structure has had time to depolarize with no cathodic protection applied.

 

3)         UST systems with impressed current cathodic protection systems shall also be tested and inspected, prior to being put into operation and every 30days thereafter, to ensure the equipment is running properly and the entire system must be tested yearly.

 

4)         For UST systems using cathodic protection, records of the operation of the cathodic protection shall be maintained  to demonstrate compliance with the performance standards in this Section.  These records shall provide the following:

 

A)        The results of testing for sacrificial anode systems, the 6-month test and 3 year or yearly tests must be maintained on site for 3 years; and

 

B)        For impressed current systems, a log of the 30-day inspections shall be kept for 3 years and the yearly system test shall be kept for 3 years and these records shall be kept on site.  The inspection shall include date of inspection, initials of person inspecting, power status, volt, hour and amp readings.

 

5)           Alternative methods of corrosion protection may be used if approved in writing by the Office of the State Fire Marshal provided they are no less protective of human health or the environment.

 

(Source:  Amended at 27 Ill. Reg. 8164, effective May 1, 2003)