Bubble leak testing (LT) is a non-destructive leak detection technique used to identify and locate leaks in structural components such as tanks or pipelines. The method is based on observing the formation of gas bubbles at the leak site, allowing for the precise detection of defects.
The test is performed by applying a foaming solution to the surface being inspected and then creating a pressure difference between the interior of the asset and the surrounding environment. If a leak is present, gas escaping through the defect forms visible bubbles in the solution that are visible with the unaided eye.
The bubble method is used for leak detection in storage and pressure tanks, pipelines, and industrial installations, welded joints in steel structures, as well as components of HVAC systems and energy equipment. It is particularly valuable when access to the test surface is limited to one side and other inspection methods are impractical.
Before testing, the surface must be thoroughly prepared—cleaned of contaminants, degreased, and dried. The procedure involves applying the foaming agent, generating the pressure difference (e.g., using a vacuum pump), and careful visual monitoring the surface for any signs of leakage.