California ICC UST Inspector Practice Exam

Which of the following is NOT a tank tightness testing method?

1. Volumetric

2. Precision

3. Tracer chemicals

4. Optical pigs

The correct answer is: Optical pigs

The method identified as not being a tank tightness testing method is optical pigs. Tank tightness testing is crucial for ensuring that underground storage tanks (USTs) do not leak hazardous substances into the environment. Volumetric testing, precision testing, and tracer chemical methods are all established techniques used to evaluate the integrity of USTs. Volumetric tests measure the amount of liquid in a tank and check for discrepancies over time, indicating potential leaks. Precision testing, on the other hand, can provide a more sensitive measurement to identify small leaks. Tracer chemicals involve introducing a detectable substance and monitoring for its presence outside the tank, which helps determine if a leak exists. Optical pigs, however, are devices used primarily for inspecting and cleaning pipelines. They employ visual technology to assess the condition of the pipeline as they move through it, but they are not relevant to the testing method for tank tightness. Thus, they do not serve the purpose of evaluating the integrity of USTs like the other options do.