Comparing Pressure Decay and Mass Flow Leak Tests

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Leak testing is an important service for many industries for a number of reasons: not only does it prevent dangerous leaks and problems in everything from medical devices to automotive systems, but it also helps assure consumers that a product is a trustworthy purchase. Unfortunately, with the number of different types of leak detection tests, it can be difficult to determine which procedure is right for your company. This article seeks to explain the difference between two popular methods: pressure decay leak testing and flow-based leak tests. Hopefully, this will be able to clarify which leak detection service is right for you.

Pressure Decay Leak Testing
In pressure decay leak testing, the component being tested is pressurized, or filled with air until reaches a set pressure. Then, it is isolated from the air supply and monitored with a pressure sensor. As the air leaks out, the pressure drops, allowing the user to calculate the leak rate over time. Many manufacturers and engineers prefer pressure decay leak testing because it can sense even the smallest leaks, is one of the least expensive techniques to implement, and is also considered one of the simplest methods. However, it must be carefully calibrated against an accurate leak standard to yield correct results.

Mass Air Flow Leak Testing
In comparison, flow-based leak tests pressurize the part being tested, but it remains connected to the air supply. Once an equilibrium is reached and the pressure is stabilized, the amount of gas flowing into the component is measured. This level must be equal to the amount of gas flowing out of the part. This technique sometimes simpler because the leak rate is measured directly and does not require conversion. It also does not need to be recalibrated to test a different part. However, this method is sensitive to pressure fluctuations, is not well-suited to measuring low leak rates or very small volumes, and requires more equipment, making it more expensive to implement.

Which Test Should You Choose?
Before you choose a leak testing procedure, it is important to consider a number of factors, including the test pressure requirements, cycle time limitations, repeatability targets, even the temperature sensitivity of the part and the test environment. Once these details have been analyzed, you should think about the product you will be testing. For example, will you be testing a variety of different parts of different sizes and volumes? In that case, mass air flow leak testing will likely be better for your operations. However, do you need an affordable method to accurately detect even the smallest leaks? Pressure decay leak testing is probably the option for you. By thinking over all of the details of your application, you can find the right leak testing method for your business. Ask yourself: what do you need from your leak detection services?

About: Ed