Pressure decay has been the most widely used method of leak testing in manufacturing production lines for decades. The process is uncomplicated, inexpensive and easily automated. Air is simply injected into a test object and any decrease in air pressure over time signifies a leak. However, the pressure decay method has significant shortcomings such as limited sensitivity and the inability to determine leak location.

A relatively new technology, hydrogen leak testing, addresses these shortcomings. Hydrogen testing functions as an enhancement to pressure decay systems or as a substitute method, depending on the application. The hydrogen and pressure decay methods are complementary, utilizing similar test procedures and test apparatus.

The hydrogen method employs a robust, self-calibrating and maintenance-free microelectronic probe that’s extremely sensitive and 100 percent selective to hydrogen. The test gas (a nonflammable mix of hydrogen and nitrogen) is injected into the test object and leakage is detected in a variety of ways: The test object can be enclosed in an accumulation chamber, where the presence of hydrogen is measured over a certain time interval to determine the total leakage. Alternatively, a hydrogen probe can scan the object’s exterior, either manually or robotically, to pinpoint the location of leaks.

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