The requirements for internal visual inspections are set forth in 49 CFR 180.407(e). At minimum, the internal visual inspection should include the following:
- Inspect the tank shell and heads for corroded and abraded areas, dents, distortions, defects in welds, and any other condition that might render the tank unsafe.
- Inspect tank liners using the lining test procedures.
- Thickness test corroded or abraded areas of the CT wall according to thickness test procedures.
When the CT is not equipped with a manhole or inspection opening, or the CT design precludes an internal inspection, the CT must be either hydrostatically or pneumatically tested in accordance with the pressure test procedures. Results of the inspection must be recorded and include any defects discovered and steps taken to remedy the defect.
