Inoperative 365+ Days
Any impressed current system that is determined to be have been inoperative for greater than 365 days must comply with the following additional requirement. An internal inspection of the tank shall be performed by a third party according to the following requirements:
1. Any tanks that are internally lined the internal inspection must be in accordance with API 1631 – “Interior Lining and Periodic Inspection of Underground Storage Tanks.”
2. Tanks that are not interior lined shall be inspected in accordance with ASTM G 158 – “Standard Guide for Three Methods of Assessing Buried Steel Tanks.”
If the tank fails the internal inspection it must either be permanently closed and removed, or lined, or any present lining must be repaired per API 1631, and the impressed current system must be assessed, surveyed, repaired and re-commissioned by a certified corrosion expert.
If the tank is not closed then a precision tightness test must be performed on the tank system, by a certified tank system tightness tester, and the tightness test shall test 100 percent of the tank’s volume.