Abstract: Apparatus and method for detecting leaks within underground or aboveground tanks and their associated piping whether the tank and/or piping is partially filled or empty. The apparatus is partially insulated to minimize temperature effects when injecting a test gas into the tank to be tested. The tank is pressurized to a fill pressure by injecting (bubbling) the test gas through any liquid in the tank. Once stabilized the pressure is reduced to a test pressure while the gas injection continues. The flow rate of gas into the tank is monitored by a flow meter able to measure small flows while the pressure is held constant by a pressure regulator having a high accuracy and the temperature of the ullage is monitored. A tight or leaking tank is determined by evaluating the flow rate of constant pressure against reference criteria which when met identify a tight tank and when not met identify a leaking tank under EPA guidelines.

Abstract: A volumetric leak detector. An overfilled storage tank has at its upper end a fill pipe predetermined surface area. An area converter reservoir is connected at this upper end with the storage tank, so that some liquid from the fill pipe flows into the reservoir. The area converter reservoir has a surface area which is larger than the surface area of the fill pipe. An almost constant minimum level is provided in the area converter reservoir, and the height difference between that minimal level and the actual level of the tank are as determined.