The leak testing (or "leak test") is the industrial proceedings necessary to verify and to measure the pneumatic tightness of the produced components. Particularly this document is made for the technicians employed to the end line testing of serial products.
This phase of the industrial process is also called leak test or leakage detection. Historically the companies that are better equipped in this production phase are those ones producing articles that are essentially very dangerous, or with high technological value. Therefore we can draft the first "generation" of production types where the sensibility of this proceeding has been realized from the beginning:
Only at the turn of the eighties and the nineties it has begun a campaign in order to extend these kinds of tests for a larger products range. Around this period, in fact, people become to understand that this kind of test could be extended with a lot of advantages also to those products that were not dangerous in case of leakage.
If, for example, small oil leaks in motors or in mechanical transmission were considered acceptable in the seventies and in the eighties, from the nineties a little defect of this kind meant a non conformity by the final customer. Thanks to the application of this principle of technical availability with quite short times and low cost this testing methods expanded, and it continues to expand.
Therefore nowadays it is not possible to draft a complete list of companies where this kind of test is considered "necessary", and we can generalize that every product that can contain some gas or some fluids can take advantage of these tests.