Determining the internal volume for the ISO80369-20 leakage methods, pressure decay and subatmospheric pressure air leakage

The ISO 80369 and ISO 18250 series of standards include leakage tests that require the application of a positive or subatmospheric pressure to a connection between a small bore connector or reservoir connector and a reference connector. The test methods include formulas that are used to calculate the leakage rate. At the end of the test the leakage rate is assessed to determine whether the sample under test conforms with the performance requirements of the standard.

Enersol’s Automated Subatmospheric Pressure Air Leakage Tester has been designed for the subatmospheric pressure air leakage test, and similarly the Automated Pressure Decay Tester has been designed for the pressure decay test. Both systems are automated, easy to use, have a touch-screen interface, and, calculate the leakage rate at the end of the test.

The leakage rate formulas contain a number of components of which one is an internal volume (v). This internal volume must be determined and the standard does not provide any guidance on how to do this.

The definition of the volume differs slightly between the pressure decay and subatmospheric pressure air leakage methods, and the definition is also ambiguous. Enersol’s interpretation of the internal volume is that it includes all the parts of the test system that are pressurised (or evacuated). Enersol has written a whitepaper about this issue to provide laboratories with some guidance as to how to determine the internal volume under test.

The full whitepaper can be accessed here:

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