What is a common method used for testing underground fuel tank integrity?

Pressure testing is a commonly used method for assessing the integrity of underground fuel tanks because it evaluates whether the tank can maintain a certain pressure over time, indicating that there are no leaks or structural failures. This method involves filling the tank with a liquid, typically water or another testing fluid, and applying pressure. If the pressure remains stable, it suggests that the tank does not have leaks and is structurally sound. This technique helps ensure that potentially hazardous fuel does not escape into the surrounding soil or groundwater, which is crucial for environmental protection and regulatory compliance.

Other methods, while useful, do not provide the same level of assurance specific to identifying leaks under pressure conditions. Soil sampling can help identify contaminants but does not directly measure the tank's structural integrity. Visual inspection may reveal obvious external issues but is often inadequate for detecting small leaks. Ultrasonic testing is primarily used for evaluating the thickness of tank materials and detecting corrosion but may not fully assess the tank's ability to hold pressure over time.