Why use helium for leak testing?
Helium is one of the smallest gas molecules and is inert (remember your periodic table from Chemistry?). Being inert it is relatively safe to use (rather than hydrogen) and will not react with any of the materials within the part to be tested. In most helium leak testing applications, one uses a mass spectrometer tuned to detect helium. Helium leak testing can be generally be between one thousand and one million times more sensitive than using pressure decay techniques. What are the benefits of Helium Leak Testing? Using this technique you can leak test to find smaller leaks than with other test processes, using a temperature stable, dry technique. This should result in a longer product life. There are 2 basic techniques; high vacuum testing which allows leak test thresholds to be set down as low as 1×10-12mbar.l.sec-1, or sniffing which is generally used for helium leaks down to 1×10-6mbar.l.sec-1. For reference 1 cubic millimetre per second is approximately 1×10-3mbar.l.sec-1. Most t
