Leak rate metrology for the society and industry

Leak detection is a non-destructive test performed to verify materials and components in agreement with the prescribed specifications, by using techniques, which do not damage their characteristics or performances. The leak check of fluids dates back in time; it started to be applied at the end of the 19th century when the electron was discovered and early in 20th century when the first mass spectrometer was realized. Today, for environmental and personal safety more effective leak detection and location capabilities on various artifacts are necessary. Leak detection techniques are widely applied in many branches of industry. In the paper leak test requirements in general and the differences between the test methods are shortly reviewed. The choice of proper leak detection technique is related to the sensitivity and leak thresholds. Whatever method is chosen, a traceability chain must be guaranteed starting from the NMIs that have developed primary standards.