Pressure Decay Leak Test

What is a Pressure Decay Leak Test?

Pressure decay is one of the most widely used methods of leak testing in manufacturing and is ideal for a sealed component with an access port. In this test, a product is attached to a leak tester and filled with air. Once pressurized, the air source is valved off and the pressure is allowed to settle. During the test any decrease in air pressure over time signifies a leak. If the part does not leak/decay past its predetermined reject value, it is a good part. The sensitivity of this test is dependent upon the product’s size and the time interval of the test. Larger objects require a longer cycle time to reach a high enough sensitivity for a quality test. Smaller objects with small internal volumes will require very low cycle time, allowing a high throughput of production.



 

Here’s how it works:

1. Connect your part to a Zaxis leak tester with a fitting or fixture. During the FILL stage your part is pressurized.
2. Once the desired test pressure specified by the manufacturer has been reached and the fill time has ended, the SETTLE stage commences accommodating for part stretching or flexing.
3. Once the part has settled and the settle time has ended, the pressure decay TEST initiates. During the test stage a pressure sensor will measure any drop in pressure.
4. After the pressure decay test the remaining pressure in the system is vented to atmosphere during the VENT stage.
5. If the pressure decay of your part remains within your specification then your part PASSES and a green light illuminates. If the pressure decay of your part falls below your lower limit, then your part FAILS and the red light illuminates.

The advantage of this type of testing is that it is accurate up to the 5th decimal place or 0.00001 PSI allowing for fast test cycles.
   

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