Testing with a tracer gas is one of the most effective methods for detecting and measuring leaks.
Helium is the most commonly used tracer gas for leak testing, because it is the lightest of the inert gases and mass spectrometers are extremely sensitive to trace amounts. However, mass spectrometers can be delicate and expensive to maintain. The instrument’s pumps must be regularly checked and serviced. In addition, the helium itself can cause problems. Helium is expensive and highly viscous. If it spills, it can be difficult to clear from the testing equipment. It also tends to cling to surfaces.