Leak testing is a form of non-destructive testing used for the detection and location of leaks and for measurement of fluid leakage in either pressurized or evacuated systems and components. A leak may be a crack, crevice, fissure, hole or passageway that admits water, air or other fluids or lets fluids escape. The word “leakage” refers to the flow of fluid or gas through a leak without regard to the physical size of the hole through which flow occurs.
Leaks are special types of flows that can have tremendous importance where they influence the safety or performance of engineering systems. The operational reliability of many devices is greatly reduced if sufficiently large leaks exist. The end purpose of leak testing is to ensure reliability and serviceability of components and to prevent premature failure of systems containing fluids under pressure or vacuum. Leakage has now become a serious concern in the fabrication of nuclear reactor components, unfired pressure vessels, and vessels containing lethal substances. Leak testing is also used on other components or systems utilized in processing of fluid materials that are affected by the presence of contaminants that react with the product. Leak tests are now made on pyrotechnic devices, electronic components, automotive air conditioners, food packages and other test objects.
The high variety of products to be sealed hermetically requires development of diverse methods and equipment for leak testing.