What is one of the primary methods for detecting leaks in underground fuel tanks?

Using a vacuum testing system is one of the primary methods for detecting leaks in underground fuel tanks because it involves creating a vacuum within the tank and monitoring for any changes in pressure. If there is a leak, the pressure will drop, indicating that fuel is escaping from the tank. This method is particularly effective as it can detect small leaks that might not be apparent through visual inspection or other methods.

In contrast, regular visual inspections rely on observable signs of leaks, which might not always be present or visible, especially in underground tanks where fuel could seep into the surrounding soil without leaving obvious traces. Ultrasonic testing, while useful in some applications, is less common for leak detection in underground tanks compared to vacuum testing, as it typically involves assessing the thickness of the tank material rather than directly detecting leaks. Liquid level measuring can indicate a leak if there is a drop in fuel levels, but it cannot precisely pinpoint where the leak has occurred.