Steel in wet soil corrodes. Cathodic protection stops that by making the tank the wrong end of an electrical circuit, and 40 CFR 280.31 sets two separate obligations to confirm it is still working. A test of whether the protection is adequate, every three years. A check that the equipment is running, every 60 days. Only one of them applies to every protected system.
Two systems, two sets of duties
Cathodic protection comes in two forms and the rule treats them differently, so the first question is which one is in your ground.
A galvanic system, often called sacrificial anode, uses a more reactive metal buried near the tank. The anode corrodes instead of the steel. It has no power supply and no moving parts, and an STI-P3 tank is the common example.
An impressed current system uses a rectifier to push a current through anodes from mains power. It works on larger or more difficult installations where a sacrificial anode cannot supply enough current. It also has a box on a wall that can be switched off, tripped, or quietly failed.
Both get the periodic test. Only impressed current gets the 60-day check, for the obvious reason that a sacrificial anode has no equipment to be running.
The periodic test: three years, qualified tester
280.31(b)(1) sets the frequency. All cathodic protection systems must be tested within 6 months of installation and at least every 3 years after that, or according to another reasonable time frame established by the implementing agency.
That last clause is doing a lot of work, and it is why the three year number should be treated as a starting point rather than an answer. States use it. Connecticut requires annual cathodic protection testing for any UST system using a cathodically protected component, which is a third of the federal interval.
Two constraints come with the test. It has to be performed by a qualified cathodic protection tester, and the criteria used to decide the protection is adequate have to follow a code of practice developed by a nationally recognized association. The rule names five that qualify: NACE TM0101, NACE TM0497, STI R051, NACE SP0285 and NACE SP0169.
A report that gives you a set of voltage readings with no stated criterion is a report you cannot use. Ask which code of practice the tester worked to, and check it appears on the paperwork.
The 60-day check
280.31(c) is one sentence. UST systems with impressed current cathodic protection must be inspected every 60 days to ensure the equipment is running properly.
In practice that is reading the rectifier: confirming it has power, and that the voltage and current output match what the system was set up to deliver. It takes a few minutes and needs no contractor. Its value is that a rectifier which trips in February and is found at the next three-year test has left the steel unprotected for most of three years, and nothing about the site looks different in the meantime.
Sixty days is an awkward interval. It is not a month and it is not a quarter, so it drifts against every other cycle on the site and against payroll, deliveries and inspections. Most operators run it monthly instead, which is inside the requirement and lands on a date somebody can remember. Some states require monthly outright.
A records rule that counts documents
280.31(d) is worth reading closely because it does not work like the rest of Part 280. Instead of a retention period in years, it asks for a count:
- The results of the last three 60-day inspections.
- The results of testing from the last two periodic inspections.
Three rectifier readings covers about six months. Two periodic tests on a three year cycle reaches back roughly six years, and on Connecticut's annual cycle reaches back two. The second one is the reason a site that changed hands needs the previous owner's last CP test report. Without it you are one document short of the requirement on day one, and no amount of testing going forward fixes a missing historical record.
What a failed test means
280.31(a) sets the standard the tests are measuring against: corrosion protection systems must be operated and maintained to continuously provide corrosion protection to the metal components that routinely contain product and are in contact with the ground.
Continuously is the word to notice. A system that fails its test was not providing protection at the moment of the test, and probably not for some time before it. That puts the site into repair rather than into a rescheduling conversation, and depending on how long the gap ran and what the soil is like, it can put the tank into a release investigation as well.
How FastDragon handles it
Cathodic protection appears on a site's calendar only when the site profile says the system exists, and the 60-day rectifier check appears only when the profile says impressed current. A site with fiberglass tanks and no protected components is asked for neither, and the reason is on the record rather than left as an absence somebody has to interpret.
Because the interval is a state question rather than a federal one, the calendar takes the state's number. A Connecticut site gets the annual test. Records are filed against the requirement they close, which is what makes the two-test lookback answerable when a site is being sold or bought.
Common questions
How often does cathodic protection have to be tested?
Under 40 CFR 280.31(b)(1), within 6 months of installation and at least every 3 years after that, or on another reasonable time frame set by your implementing agency. Several states use that clause to shorten it. Connecticut requires annual testing for any UST system using a cathodically protected component.
What is the 60-day check and does it apply to me?
Only if your system uses impressed current. 280.31(c) requires impressed current cathodic protection systems to be inspected every 60 days to confirm the equipment is running properly. A galvanic or sacrificial anode system has no powered equipment, so there is nothing to check on that cycle. The 60-day check is a look at the rectifier, and it is a different obligation from the three year test of whether the protection is actually adequate.
Can my own staff do the testing?
The 60-day rectifier check is an equipment check and generally sits with site staff. The periodic test is different: 280.31(b) requires inspection for proper operation by a qualified cathodic protection tester, and the criteria used have to follow a code of practice from a nationally recognized association. The rule names NACE TM0101, NACE TM0497, STI R051, NACE SP0285 and NACE SP0169 as codes that may be used.
How many of these records do I have to keep?
280.31(d) counts records rather than years, which is unusual. Keep the results of the last three 60-day inspections and the results of testing from the last two periodic inspections. On a three year cycle that second one means roughly six years of history for two documents.
My tanks are fiberglass. Does any of this apply?
The section applies to metal UST systems with corrosion protection. Fiberglass tanks with no metal components in contact with the ground fall outside it. Be careful before concluding that, because flex connectors, swing joints and steel piping runs are metal components that routinely contain product and touch soil. Connecticut states the test is required for any UST system using a component that is cathodically protected, which is a component test rather than a tank test.