Applus+ can perform the various methods of leak testing on new components, as directed by relevant codes and procedures, or work with a customer to assist in locating leaks within their operating systems and existing assets.
There are numerous methods of leak testing, with the most common being:
Direct-pressure bubble leak testing
Vacuum-box bubble leak testing
Halogen diode detector probe testing
Helium mass spectrometer detector-probe, tracer-probe and hood testing
Thermal conductivity detector probe testing
Ultrasonic leak detector testing
These methods are used to either determine the location of leaks or to determine an actual leak rate.
Leak testing may be performed on systems in almost all industries, whether it be liquid- or gas-piping systems, heat exchangers, pressure vessels, tanks or numerous other system and plant components.
KEY CUSTOMER BENEFITS
The advantages of leak testing are twofold:
First, it is extremely beneficial to perform a leak test on a component or system prior to it being put into service. For example, a helium leak test on a heat exchanger can verify the leakage rate across the tube-to-tube sheet welds as well as determine if there is leakage in a tube itself. Another example is performing a vacuum box leak test on a tank floor.
Secondly, if a leak is suspected in a system, performing one of the leak test methods can help determine leak locations for repairs.
Leaking systems can adversely impact on the environment, system performance and/or a company’s finances due to the loss of product and significant downtime.
Bubble leak testing is used to find leaks in many different components. The two most common forms of bubble leak testing are the direct-pressure technique and the vacuum-box technique.
The direct-pressure technique is conducted by pressurising a component with a gas and then either submerging it in a solution or applying a solution to the outside of the component. If a leak is present, bubbles will form on the surface because of the leaking gas passing through the solution.
The vacuum-box technique is conducted on parts that cannot be directly pressurised or where access is not available to both sides of a component. The test is conducted by applying a solution to an area of a pressure-boundary surface and creating a differential pressure across the area, causing the formation of bubbles as leakage gas, such as atmospheric air, passes through the solution.