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UST Program - Available Local Guidance (LG) Letters

UST Program - Local Guidance (LG) 136-1


LG 136-1 -INTERIOR LINING AND CATHODIC PROTECTION OF
UNDERGROUND STORAGE TANKS (USTs)


March 14, 1998

To: Local Agencies and Other Interested Parties

As tank owners prepare to meet the December 22, 1998 deadline for upgrading single-walled tanks, we expect local agencies to receive many requests for permits to use interior lining and cathodic protection to meet those requirements. This LG is amended to update the contractor's licensing requirements explained below. Changes are shown in bold italics.

The purpose of this letter is to outline tank lining and cathodic protection requirements and to provide references to specific sections of the UST regulations. For exact regulatory language, please refer to the California Code of Regulations (CCR), Title 23, Division 3, Chapter 16, Article 6, "Underground Storage Tank Upgrade and Repair Requirements". The numbers in the boxes in the margins refer to sections of the UST regulations.

There may be tank lining requirements in addition to those in the UST regulations. For example, the local air quality authority or fire department may have their own requirements and should be consulted.

I hope this answers questions you may have regarding UST interior lining and cathodic protection. Questions may be directed to David Holtry at (916) 227-4332.

Sincerely,

 
[Original signed by:]

Allan Patton, Manager for James George Giannopoulos
Supervising Engineer

Enclosures (3)

[Enclosure 1]

INTERIOR LINING AND CATHODIC PROTECTION OF
UNDERGROUND STORAGE TANKS

FOLLOWING ARE ANSWERS TO COMMONLY ASKED QUESTIONS CONCERNING UPGRADING USTS BY INTERIOR LINING AND CATHODIC PROTECTION:

DO LINING MATERIALS AND PROCESSES NEED TO BE THIRD-PARTY LISTED OR CERTIFIED?

YES. Tank lining materials and processes must be third-party evaluated by an independent testing organization in accordance with voluntary consensus standards. Some of those standards include: UL 1856 (Underwriters Laboratories), NLPA 631 (National Leak Prevention Association), API 1631 (American Petroleum Institute), and Uniform Fire Code 79-6.

An independent testing organization tests products or systems to make sure they comply with voluntary consensus standards. The organization must conduct periodic inspections of the production of products or systems to make sure that the product or system continues to meet appropriate standards. And the organization must have no financial interest in the product or system being tested.

Tanks may be lined only in accordance with the third-party evaluation. For example, some evaluations limit the lining material and process to steel tanks only. Other lining materials and processes are limited to petroleum products only.

IS A CONTRACTORS' LICENSE REQUIRED TO LINE TANKS?

YES. The Contractors' State License Board (CSLB) allows only those contractors who possess one of the following licenses to line tanks:

  • General Engineering Contractor (A)
  • General Building Contractor (B) as long as the contract involves the use of at least 2 or more unrelated trades or is subcontracted to the appropriate license.
  • Limited Specialty/Service Station Maintenance (C-61/D40)*
  • Limited Specialty/Synthetic Products (C-61/D12)
  • Limited Specialty/Protective Coating (C-61/D51)*
  • Painting and Decorating (C-33)
  • Plumbing Contractor (C-36)
*This license is no longer issued, but valid licenses may still exist.

The Hazardous Substance Removal Certification issued by CSLB is required for installation, repair, upgrading and/or removal of an underground storage tank. Upgrading includes installation of a bladder system or application of interior lining.  

CSLB does not require contractors to possess the hazardous substance removal certification to line tanks.

See LG 48-5 for more information concerning licensing requirements or contact CSLB at 916-255-3900 or at their website (see above).

WHICH TANKS MAY BE LINED?

Tank lining may be performed only on tanks storing motor vehicle fuel. Lining may be performed as a preventive measure to satisfy the December 1998 upgrade requirements for steel tanks. However, single-walled fiberglass tanks storing motor vehicle fuel do not require lining or replacement by 1998. Likewise, single-walled steel tanks which store motor vehicle fuel and are clad on the outside with fiberglass or another non-corrosive material do not require lining or replacement.

IS SOIL SAMPLING REQUIRED PRIOR TO LINING?

This is left up to the local agency. In accordance with sections 25296(c) Health and Safety Code, a continuous vapor or ground water monitoring system must be installed adjacent to a single-walled tank if the tank that is proposed to be interior lined had previously leaked. The purpose of the continuous monitoring system is to differentiate between any residual contamination from the prior leak and any future failure of the operational integrity of the lining. There is no requirement to install this monitoring system where it can be determined to the satisfaction of the local agency that the tank itself has not previously leaked.

The law gives broad authority to the local agencies to adopt more stringent requirements (Section 25299.2 Health and Safety Code) including the determination of whether a tank has previously leaked. In the past, some local agencies have required soil samples at each end of the tank. Others have trusted monitoring results such as the most recent tank tightness test. Since a tank test result can only determine whether a tank is leaking at the time the test is performed, reviewing inventory reconciliation records over long periods may be beneficial. And finally, some local agencies consider the inspection results from the special inspector who enters the tank and performs evaluations on the tank shell when determining whether the tank itself has previously leaked.

If the local agency chooses to require soil samples to determine whether the tank itself has previously leaked, then only samples at locations adjacent to the tank are necessary to verify whether the tank itself has leaked (as opposed to piping leaks, dispenser leaks, spills, overfills, etc.). Therefore, it is not necessary to take soil samples underneath dispensers or along lengthy piping runs to determine whether a continuous vapor or ground water monitoring system must be installed during the lining process.

CAN TANKS THAT HAVE PREVIOUSLY LEAKED BE LINED?

YES. Section 25296(a) Health and Safety Code allows a tank to be repaired by lining. Lining may be performed to repair a steel, fiberglass, or clad tank that has minimal structural or corrosion problems. However, a tank that was previously lined may not be lined a second time if it leaks. In other words, relining of a previously lined tank that has leaked is not allowed so as to avoid repeated repair of a tank that is fundamentally unsound.

CAN TANKS LOCATED AT CONTAMINATED SITES BE LINED?

This will depend upon the results of a soil and ground water investigation. If any of the conditions in section 2724 CCR are present, then a complete soil and ground water investigation of the entire site must be completed to determine the effects of contamination. Consequently, conditions may exist that require soil and ground water investigations involving sampling in order to assess the effects of contamination, if any. If there is known contamination, regardless of the source, soil and/or ground water sampling is required to conduct a site assessment in accordance with Article 11 CCR. With concurrence from the regulatory agency overseeing cleanup, a tank that has leaked may be repaired by lining if the contamination can be remediated and mitigated with the tanks in place. On the other hand, if the site assessment indicates that tank removal is necessary to remediate or mitigate potential adverse affects of the unauthorized release, then tank lining should not be allowed.

WHAT TESTS ARE REQUIRED PRIOR TO TANK LINING?

Before a tank may be lined, a special inspector (i.e., qualified professional engineer) must certify in writing that the tank is suitable for lining and continued use. Article 6 does not require the engineer to be financially independent of the tank owner or lining company. After the tank is emptied, cleaned, purged, and tested by ultrasound for thickness, the engineer must enter the tank and perform several tests on the tank's interior. For steel tanks, the tank must be cleaned and sandblasted to white metal. The engineer must perform a visual inspection in which he counts the number of holes, splits, perforations, and other defects in order to certify that the tank is structurally sound. For fiberglass tanks, the engineer must perform a visual inspection and take interior diameter measurements to determine if there is structural, tension, or compression problems.

If the engineer certifies that the tank is suitable for lining and continued use, all holes, splits, defects, and thin areas must be reinforced before application of the lining. Materials used to reinforce or plug holes must be compatible with the substance that will be stored. Striker plates must be installed beneath all tank openings that could be used for manual dipsticking.

WHAT TESTS ARE REQUIRED IMMEDIATELY FOLLOWING LINING?

After the tank is lined, but before it is returned to service, a qualified coatings expert, who is independent of the tank lining company and who has no financial interest in the tank, must enter the tank and conduct several evaluations to ensure that the tank was properly lined. A special inspector (i.e., a qualified professional engineer) may do this in lieu of the coatings expert. In addition to a visual check of the lining, the lining must pass thickness, hardness, and electrical resistance holiday detector tests (the latter is necessary for steel tanks only). If the tank passes those tests, then the access opening is closed, and a vacuum test and a tank integrity test must be performed. If the tank and lining pass all these tests, then the tank may be returned to service.

IS CATHODIC PROTECTION REQUIRED?

YES. If the exterior surface of the tank is unprotected from corrosion, the tank must be retrofitted with cathodic protection by December 22, 1998. However, if the lining applicator or special inspector notices corrosion during the lining process, then the tank must be retrofitted with cathodic protection before the UST is returned to service.

Cathodic protection systems that are retrofitted on existing tanks must be designed by a corrosion specialist. A corrosion specialist must be certified by the National Association of Corrosion Engineers (NACE) or be a qualified professional engineer. Cathodic protection systems must be tested by a qualified person within six months of installation and at least every three years thereafter. The purpose of these inspections is to ensure that the tank and piping maintain proper corrosion protection in accordance with voluntary consensus standards (such as NACE-02-85 or API 1632). In addition, impressed current cathodic protection systems must be checked every 60 days to ensure that they remain in proper working order. Cathodic protection systems must be checked within six months of any construction in the vicinity of a cathodically-protected UST if the construction could have affected the cathodic protection system. This is to verify that no damage was done to the electrical system.

If piping connected to the tank is single-walled, constructed of steel , and it is not replaced with new double-walled piping, then the cathodic protection system must also protect the piping from corrosion. Stainless steel, galvanized steel, coated steel piping, and wrapped steel piping are not considered corrosion-protected, and therefore, must be replaced or upgraded with cathodic protection by December 22, 1998. Other metal components of the UST system (such as submersible pumps) that routinely contain fuel and are in contact with the ground must also be cathodically-protected by December 22, 1998.

WHAT FUTURE TESTS ARE REQUIRED OF THE INTERIOR LINING AND TANK SHELL?

Within 10 years of the lining, and every five years thereafter, a coatings expert must conduct an evaluation of the tank and lining. A special inspector (i.e., qualified professional engineer) may do this in lieu of the coatings expert. Depending on whether the tank is steel or fiberglass the evaluation must include: cleaning, visual inspection of the interior, interior diameter measurements, ultrasound thickness test of steel walls, thickness test of lining, hardness test of lining, electrical resistance holiday detector test, and a vacuum test. After the evaluation, the coatings expert or special inspector must certify one of the following:

  • The tank is suitable for continued use for a minimum of five years.
  • The tank is suitable for continued use for a minimum of five years only if it is relined or other necessary improvements are made.
  • The tank is no longer suitable for continued use and must be closed immediately.
IF A SINGLE-WALLED TANK WAS LINED PRIOR TO THE ADOPTION OF THE STATE'S LINING REQUIREMENTS, WHEN DOES IT NEED TO BE INTERNALLY INSPECTED?

If a tank was lined prior to August 1991, then it must be internally inspected by December 1998 in order to determine that the tank shell and lining meets the upgrade requirements. However, if a tank was lined prior to August 1991 and it can be shown that interior lining was conducted in accordance with the lining requirements that became effective in August 1991, then the internal inspection is not required until 10 years after the lining was applied.

DO TANKS THAT HAVE BEEN LINED, NEED TO BE MONITORED FOR LEAKS?

YES. Tanks that have been lined and connected piping must be monitored for leaks in accordance with Article 4 CCR. The requirements for monitoring lined tanks and connected piping are the same as those for monitoring single-walled tanks and piping that have not been upgraded.

[Enclosure 2]

EXAMPLE PLAN CHECK FOR
CATHODIC PROTECTION SYSTEM UPGRADES

1. System designed and certified as adequate by a corrosion specialist.

2. Cathodic protection for piping.

3. Cathodic protection for other metal components of UST system that routinely contain hazardous substances and are in contact with the ground.

4. If anodes are installed in wells, are the cathodic protection wells constructed in accordance with State Department of Water Resources standards?

5. If anodes are installed in wells, are the cathodic protection wells constructed in accordance with local requirements.

6. System tested by a cathodic protection tester within six months of installation in accordance with a voluntary consensus standard.

7. System tested every three years by a cathodic protection tester in accordance with a voluntary consensus standard.

8. System checked every 60 days by tank operator to ensure proper working order (impressed current systems only). Is there a written log of the visual observations maintained on-site?

9.Within 6 months of construction in the vicinity of any cathodically-protected UST system, the cathodic protection system tested by cathodic protection tester in accordance with a voluntary consensus standard.

10.Installation, testing, and monitoring records maintained for remaining operating life of tank.

 
 

[Enclosure 3]

EXAMPLE PLAN CHECK FOR TANK LINING

1. Obtain a complete third-party evaluation of the lining material and procedures:

a. A resume, including all applicable formal training experience, from personnel who conducted the evaluation (not necessary for Underwriters Laboratories).

b. An affidavit from the company that received the third-party evaluation confirming that there are no mutual financial interests between lining company and testing organization (not necessary for Underwriters Laboratories).

c. A description of the testing organization's formal periodic inspections of the listed/certified materials and processes. (The purpose of the formal periodic inspections is to ensure that the listed/certified materials and process continue to comply with the listing/certification.)

d. A copy of the voluntary consensus standard that was used during the evaluation or a description of the equivalent test protocol, if a voluntary consensus standard was not used.

e. The testing organization's raw field data, laboratory results, calculations, graphs, charts, etc.

f. The conclusion of the testing organization's evaluation of the lining material.

g. The conclusion of the testing organization's evaluation of the lining process.

h. Limitations on the listing/certification, if any.

i. A statement from the testing organization confirming that all equipment at the test site(s) was properly maintained and calibrated to the level of accuracy necessary for a valid evaluation.

j. A statement from the lining applicator confirming that the materials that will be used are the same materials that were evaluated by the testing organization.

k. A statement from the lining applicator confirming that the processes that will be used are the same processes that were evaluated by the testing organization.

l. A description of tank lining processes to be used by the applicator.

m. A statement from the company that received the evaluation describing training provided to the authorized applicator.

2. Does lining applicator have one of the following valid, unexpired contractors licenses:

  • General Engineering Contractor (A)
  • General Building Contractor (B)
  • Limited Specialty/Service Station Maintenance (C-61/D40)
  • Limited Specialty/Synthetic Products (C-61/D12)
  • Limited Specialty/Protective Coating (C-61/D51)
  • Painting and Decorating (C-33)
  • Plumbing Contractor (C-36)
3. Is lining a preventive upgrade or a repair of a leaking tank?
  • Results of soil samples
  • Holes that may have leaked fuel detected by special inspector
  • Results of tank integrity tests
  • Other monitoring results
4. Corrective action, if necessary. Will lining inhibit or delay corrective action, if any?

5. A guideline provided by lining company for local agency inspectors to use when conducting field inspections of tank linings.

6. Certification by special inspector that the tank is suitable for lining and continued use:

a. Steel or clad tanks
i. sandblast to white metal
ii. ultrasound thickness test of steel walls by appropriately trained person
iii. count number of holes, splits, perforations, and other defects
b. Fiberglass tanks
i. interior walls cleaned by wipe down
ii. interior diameter measurements
iii. visual check for structural, tension, or compression problems
7. Is the special inspector an appropriate registered professional engineer?

8. Holes and splits in steel tanks, if any, plugged with self-tapping bolts, boiler plugs, water-tight, hydraulic cement, or welding.

9. Striker plates installed beneath all tank openings that could be used for manual dipsticking.

10. Lining applied within 8 hours of sandblasting?

11. Berfore UST is returned to service, certification by coatings expert or special inspector that tank was lined properly:

a. Steel or clad tanks
i. visual check of lining
ii. thickness test of lining
iii. hardness test of lining
iv. electrical resistance holiday detector test
v. vacuum test
b. Fiberglass tanks
i. visual check of lining
ii. thickness test of lining
iii. hardness test of lining
iv. vacuum test (not required if submerged by 50% of depth in ground water)
12. If a coatings expert was used, is he financially independent from the tank owner and lining company?

13. Tank integrity test conducted.

14. Continuous vapor or ground water monitoring system (tanks that have leaked only).

15. Tank lining records and test results maintained for remaining operating life of tank.

16. Spill container.

17. Overfill prevention equipment.

18. Proposed monitoring procedures for the tank(s) and piping that will be used once the UST is put back into service.

19. An emergency response plan for the facility that will be used once the UST(s) is put back into service.

20. Ten years after lining and every five years thereafter, certification by coatings expert or special inspector that the tank is suitable for continued use:

a. Steel or clad tanks
i. interior lining cleaned by wipe down
ii. visual check of lining
iii. thickness test of lining
iv. hardness test of lining
v. electrical resistance holiday detector test
vi. ultrasound thickness test of steel walls by appropriately trained person
vii. vacuum test
b. Fiberglass tanks
i. interior lining cleaned by wipe down
ii. visual check of lining
iii. thickness test of lining
iv. hardness test of lining
v. interior diameter measurements
vi. vacuum test (not required if submerged by 50% of depth in ground water)
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