Leak testing methods

The basic principle used for leak tightness testing or leak measurement is based on two fundamental methods: "Pressure change measurement" and "Flow measurement". With both methods, the test specimen is initially filled with air up to an adjustable test pressure and then disconnected from the compressed air supply. The actual measurement then begins.

With this method, the leakage is determined on the basis of pressure change. If there is a leak present, this brings about a change in pressure which can be converted with the aid of the test volume and the measurement time into a leakage rate. This method can be also be executed in the form of a vacuum test.

The flow measurement method supplies a measurement signal which is independent of the size of the test volume and the measurement time, which correlates to any existing leak. Unlike the pressure drop method, here no conversion is required.