The surface bubble method (LT – Leak Testing) is one of the most commonly used techniques for weld integrity testing, especially where other non-destructive methods can be difficult or expensive to apply. This method involves applying a film-forming liquid to the surface of the welded joint under test. In the event of a leak, gas entering through the defect forms bubbles on the surface of the liquid, indicating the location of the leak. Typically, compressed air or another gas is used for testing, which is introduced into the system under pressure and the surface to be tested is covered with the bubble-forming liquid. The bubble method is often used to inspect welds, especially in tanks, pipelines, pressure systems and other components where leaks can pose a serious risk.
