Cathodic Protection Testing
CommTank is proud to announce that Luis Diaz has received his certification in UST Cathodic Protection from the International Code Council (ICC). The ICC codes provide minimum safeguards for people at home, at school and in the workplace and are used in the design, build and compliance process. Fifty states and the District of Columbia have adopted the ICC code at the state or jurisdictional level. The ICC U4 Certification in UST Cathodic Protection will allow Luis to inspect and test cathodic protection systems. Cathodic protection uses the electrical properties of metal corrosion to provide a system that protects the steel in Underground Storage Tanks (USTs) or metallic piping and inhibits the oxidation process.
Below are the typical methods of protection:
- Galvanic Cathodic Protection Systems
- Impressed Current Cathodic Systems Galvanic
Cathodic Protection Systems
A galvanic cathodic protection system for USTs, consists of sacrificial anodes affixed to the UST during manufacturing of the UST, and provides specified wiring for an inspection station installed near the surface of the ground. Galvanic systems have limited life spans during which the sacrificial anode will continue to degrade and protect the tank or piping. When the sacrificial anodes are no longer capable of protecting the tank or piping, they will lose their protection and begin to corrode.
Checklist for Galvanic Cathodic Protection Systems
You need to have a periodic test conducted by a qualified third party inspector to make sure your cathodic protection system is adequately protecting your UST system. This test needs to be conducted:
- At least every 3 years after the previous test with a reading of at least -0.90 volts.
- Within 60 days after any repairs to your UST system.
- Make sure the third party inspector is qualified to perform the test and follows a standard code of practice to determine that test criteria are adequate.
- If any test indicates your tanks are not adequately protected, (reading of less than –0.85 volts) you need to have a corrosion expert examine and fix your system.
- If any test indicates a reading between -0.85 and -0.90 volts then you must have your tank inspected annually.
- Testing more frequently can catch problems before they become big problems.
- You need to keep the results of the tests on site for the operating life of the facility.
Impressed Current Cathodic Systems
The impressed current cathodic protection system usually provides electrodes of a much longer life span than a galvanic anode. These systems include a rectifier that converts the alternating current power source to a direct current that is properly calibrated to provide the required protection. Since the power source is delivered to the electrode and is not generated by the degradation of the electrode, the power supply to the electrode may be recalibrated to provide additional power, when needed, as long as the electrodes are still functional.
Checklist for Impressed Current Cathodic Protection Systems
You need to have a periodic test conducted by a third party inspector to make sure your cathodic protection system is adequately protecting your UST system. This test needs to be conducted:
- At least every 1 year after the previous test.
- Within 60 days after any repairs to your UST system.
- Keep the results of at least the last two tests on file.
- Inspect your rectifier and record the readings at least every 60 days to make sure that it is operating within normal limits.
- Keep records for the operating life of the facility.
- Never turn off your rectifier!
If the system voltage and amperage readings are outside the range determined to be acceptable by the corrosion expert, the owner/operator shall immediately cause an investigation to determine if the system is operating as designed. You must contact a cathodic protection professional to address the problem.
Third Party Inspectors
New MassDEP regulations created a Third Party Inspection (TPI) certification program that requires inspectors to be certified in cathodic protection by one of the following:
- Certified in the UST Cathodic Protection category by the International Code Council (ICC)
- Certified at least at level CP1 – Cathodic Protection Tester by NACE: The Corrosion Society
- Certified as a Cathodic Protection Tester by the Steel Tank Institute (STI)
A certified Cathodic Protection Tester must have education and experience in soil resistivity, stray current, structure-to-soil potential, and component electrical isolation measurements of buried metal piping and tank systems. A certified inspector must also understand the principals and measurements of different types of cathodic protection systems.
While it is not necessary to be an “expert” to test cathodic protection systems, it should be recognized that the proper evaluation of the two types of cathodic protection systems may require differing levels of expertise. Impressed current systems are inherently more involved and require a higher level of understanding than galvanic systems. In addition, certain circumstances and conditions may exist that would preclude an individual from making an effective evaluation of a cathodic protection system without the assistance of a corrosion expert.
During a Third Party Inspection, the inspector will ensure the cathodic protection system has been installed, tested, maintained, and is fully operational in accordance with 310 CMR 80.22, 80.29 and the manufacturer’s specifications.
For more information about Cathodic Protection Testing and Third Party Inspections, contact one of our tank experts at 1-800-628-8260.