Where semi-quantitative detection of leaks of a high degree for leak-tight integrity is required, the Helium Mass Spectrometer can do the job. This is a highly sensitive test for minute leaks that must be located because of human endangerment or product contamination. The two methods commonly used are the internal pressurization with helium or the evacuation of a component and application of helium to the outside.
A Helium Mass Spectrometer with a minimum sensitivity of 1 X 10 -9 cm 3 /sec/division is usually used. There are several companies such as Varian and Veeco that manufacture these units. This equipment is used on heat exchangers, refrigeration systems, fluid fittings, pumps, distillation columns and floor plates of storage tanks.