Abstract: A system for the non-volumetric detection of low-threshold leaks with high resolution in underground storage tanks (USTs). A UST may be located underground with a restricted tank entry opening. The interior space of a UST may be accessed with a remotely controlled device. The presence of a liquid fill material or indicia thereof evidencing a leak may be visually observed. Variables affecting volumetric measurements of leak detection, such as temperature, pressure, tank deflection, and groundwater, may be eliminated or controlled. Visual observation may enable high resolution detection of low-threshold leaks.

Abstract: A system for the non-volumetric detection of low-threshold leaks with high resolution in underground storage tanks (USTs). A UST may be located underground with a restricted tank entry opening. The interior space of a UST may be accessed with a remotely controlled device. The presence of a liquid fill material or indicia thereof evidencing a leak may be visually observed. Variables affecting volumetric measurements of leak detection, such as temperature, pressure, tank deflection, and groundwater, may be eliminated or controlled. Visual observation may enable high resolution detection of low-threshold leaks.

Abstract: A leak detection method for determining changes in helium concentration over time in an interstitial space between a primary vessel and a secondary vessel. The primary vessel is disposed inside a secondary vessel and charged with helium. An expected concentration of the helium in the interstitial space resulting from permeation of the primary vessel material is calculated and accounted for to determine a leak in the primary vessel. In another embodiment of the leak detection method, air flow is circulated in the interstitial space between the primary and second vessels. An abrupt change in measured concentrations can be used to determine the approximate location of the leak in the primary vessel.

Abstract: In one aspect the method provides for determining changes in helium concentration over time in the interstitial space between a primary vessel that is charged with helium and a secondary vessel. The expected concentration resulting from permeation is calculated and accounted for. In another aspect, air is circulated in the interstitial space. An abrupt change in measured concentrations may be used to determine an approximate leak location.

Abstract: In one aspect the method provides for determining changes in helium concentration over time in the interstitial space between a primary vessel that is charged with helium and a secondary vessel. The expected concentration resulting from permeation is calculated and accounted for. In another aspect, air is circulated in the interstitial space. An abrupt change in measured concentrations may be used to determine an approximate leak location.