Internal Tank Lining Inspections
Written by: Brian Pottebaum, Director of Training Services
As part of the December 1998 EPA regulatory deadline, all steel underground storage tanks had to be upgraded to meet one of three possible corrosion protection options to continue to operate, if they did not already comply: 1) Interior lining only, 2) Cathodic protection only, or 3) Interior lining and cathodic protection.
- Interior lined only tanks are certified for 10 years. They must have the internal tank lining inspected (or re-certified) within ten years of the lining, and then every five years thereafter. For example, if a tank was internally lined January 1, 1995, it must be inspected by January 1, 2005. The tank will have to be inspected again by January 1, 2010 and every 5 years thereafter until the tank no longer passes inspection and is permanently closed.
- Cathodically protected only tanks were certified for 6 months. They had to be re-certified (or checked for adequate protection) within six months of installation of the CP system and every three years thereafter. For example, if cathodic protection (CP) was added January 1, 1995, the tanks had to be re-certified by June 1, 1995; June 1, 1998; June 1, 2001 and will have to be re-certified again by June 1, 2004. The tanks must be re-certified every three years until the tanks are permanently closed.
- Interior lined and cathodically protected tanks require re-certification of the CP system, but the owner has two options to comply with the certification requirements of the lining:
- Both the CP certification and the lining certification methods can be maintained (as defined in paragraph 1 and 2), or
- The owner can choose to only maintain the CP certification IF the CP was added before the lining or at the same time as internal tank lining. If the CP was added after the tanks were lined, or if lining was installed to repair a leak, the lining must be re-certified according to paragraph 1.
Tank Lining Re-certification
There are several items that you need to be aware of when you have your tank internal linings inspected. Tanks must be empty. Tanks must be clean (including all sludge on bottom). The inspection must be performed and passing results must be received prior to the 10-year or 5-year certification deadline. You cannot put fuel back into a tank if it fails the inspection!
There are currently two methods of conducting internal tank lining inspections:
- Manned-entry is an invasive method that requires your tanks to be completely empty and cleaned so a certified lining inspector can physically enter the tank to perform the inspection. The inspector enters the tank through a hole that is cut in the top portion of the tank. With manned entry inspection, if a repair is required, in most cases the lining can be repaired at the same time as the inspection. Once the tank is successfully repaired, it must be re-certified by the inspector and precision tested before any product is put in the tank.
- Video camera (scope) entry is a non-invasive method that requires your tanks to be emptied and cleaned so a camera can inspect the entire tank. The camera is inserted into the tank through the fill pipe (or another riser pipe) so no holes need to be cut in the tank. Although the video inspection can be set up in less time, there can be more delays, especially if repairs are needed. Video inspectors are not prepared to do any repairs at the time of the inspection, so you will need to reschedule the repair. Also, video inspections are not always reviewed on site, so you may have to wait several days or weeks to find out the results.
If a tank “fails” the lining inspection the tank cannot operate again until the cause of the failure is addressed, and the tank passes another inspection.Fuel cannot be put back into a failed tank. In addition, after a “failed” tank is repaired and before product can be put in the tank, the tank must pass a precision (0.1 gph) tightness test. Regulations require the precision test to be completed within 30 days of the repair. All lining repairs require manned entry, regardless of method of inspection.
If the tank lining cannot be repaired in accordance with a recognized industry standard, it must be permanently closed.
Retrofitted internal tank linings and cathodic protection were a quick fix to a problem that still exists today...corrosion. Neither system lasts forever, so you must be prepared to repair or replace your tanks if your corrosion protection system fails.