Testing components to ensure they are leak-tight. Leakage testing can be carried out using either the vacuum method or the overpressure method, as defined in DIN EN 1779. The testing methods outlined in DIN EN 1779 are most commonly used when testing the leak-tightness of installed systems (e.g. cooling and vacuum systems, packaging), and components and systems in series production (e.g. fuel tanks, injection pump housings).