What Does Vacuum Decay Test Mean?
Vacuum decay testing is a method used to verify the sealing integrity of a component (such as a process vessel) or part. The vacuum decay test monitors the test specimen to detect leakage from an external source into the specimen’s housing or casing. This test is in contrast to pressure leak tests where the specimen is tested for leaks coming out of the specimen.
Among other causes, a leak may indicate the presence of pitting corrosion or a pinhole in the tested component.
Corrosionpedia Explains Vacuum Decay Test
During the vacuum decay test, the part or component being tested is connected to a vacuum line and placed in the test chamber. The chamber is closed, and both the specimen and the chamber are vacuumed to a specified pressure. When the pressure is stabilized, the pressure in the test specimen is compared to the reference volume in the chamber. If there is a net pressure increase between the chamber and the specimen, then the technician can conclude that there is a leak in the specimen and that it is not properly vacuum-sealed.
Outdoor electrical housings, underwater sensor casings and other sealed components are examples of items that are commonly tested with vacuum decay testing units.