Pressure Decay Test: how leak tightness is evaluated via pressure drop

The pressure decay method monitors the pressure change in a closed section over a specific time. It is useful for leak testing, provided that temperature effects are taken into account.

Basic principle

The section is isolated, stabilized, and the pressure is monitored. An unexplained continuous drop may indicate a leak.

Stabilization

Before the evaluation begins, time must be allowed for the gas and piping to reach the most stable temperature possible.

Instrument accuracy

The pressure gauge or transmitter must have sufficient resolution for the small change we want to detect.

Limitations

Large temperature fluctuations, elastic elements, or short test duration can lead to incorrect conclusions.

Recording

Pressure, temperature, and time are recorded so that the test is documented.