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 correct answer is based on the understanding of various tank tightness testing methods used for underground storage tanks (USTs). Tank tightness testing is crucial in ensuring that tanks do not leak hazardous substances into the environment. The volumetric method involves measuring the change in volume of a liquid within the tank over a specified period. This method can help detect small leaks by observing whether the liquid level changes significantly. The precision method, also known as the statistical leak detection method, uses statistical analysis of data collected during specific testing scenarios to assess the probability of leaks occurring over time. Tracer chemicals testing involves introducing a detectable substance into the tank and monitoring its concentration to check for leaks. If the concentration of the tracer chemical decreases over time, it indicates a potential leak in the tank. Optical pigs, on the other hand, are not a recognized method for testing the tightness of fuel tanks. Instead, they are devices used for inspecting the interior conditions of pipelines and are not applicable for ascertaining whether a storage tank is leaking. Therefore, this method does not fit within the context of tank tightness testing and is rightly identified as not being a tank tightness testing method.