The ability to detect leaks in certain materials is essential for ensuring the quality and safety of those materials. To accomplish this, leak testing is used to find leaks using one of these four main techniques: Bubble, Pressure Decay, Halogen Diode and Mass Spectrometer Testing. Let’s look at each technique.

  • Bubble Emission: There are several types of bubble emission testing. The most common type is soap bubble testing where the part is sealed and pressurized with a compressed gas and then sprayed or wiped with a bubble solution. This method provides technicians with information about the presence of a leak but does not indicate the size of the leak.
  • Pressure Decay: Pressure decay leak testing is similar to bubble emission. It also includes sealing the part and pressurizing it with compressed air. The difference is the technician monitors pressure changes with a gauge in an attempt to isolate the test part from the air supply.
  • Halogen Diode Leak Testing: This method is done by pressurizing a system with a mixture of air and a halogen-based tracer gas. After a specific period of time, a halogen diode detection unit, or “sniffer”, is used to locate leaks.
  • Mass Spectrometer Testing: Helium is a commonly used trace gas used with mass spectrometers and thermal conductivity. In trace gas sniffer testing, the part is pressurized with a trace gas and a mass spectrometer or thermal conductivity tester is fitted with a sniffer probe. This probe is then moved over the areas of the possible leak to detect its presence. This test can detect not only the presence of a leak, it can also take an accurate size measurement of it as well giving technicians more information than with other testing methods.

Which Method to Choose

When it comes to leak detection no one method is best. It depends on a number of factors. You should ask yourself the following questions. What will cause the part to not operate correctly or degrade performance? How will the part be used? What type of budget is available?

Because leak detection plays such an important role in the non-destructive testing of materials, we sell ultrasonic immersion testing equipment that is used in the aviation industry to ensure the safety and quality of materials used. Our NDT equipment is technologically advanced, accurate and affordable.