ISO 6953-3:2012 specifies alternative test methods for testing pneumatic fluid power components that use compressible fluids, i.e. gases. This part of ISO 6953 is applicable only to the decreasing flow rate part of the hysteresis curve of forward flow and relief flow characteristics. This method can be applied when:

• the pressure regulation dynamics of a component under test is rapid enough to be negligible, compared to the response of pressure changes during charge and discharge tests;
• the pressure response does not show any overshoot or any oscillating behaviour.

ISO 6953-3:2012 specifies requirements for the test installation, the test procedure and the presentation of results.

Examples of test results are given, as well as various data processing methods, and visualization of data processing procedures. Illustrations of overshoot and undershoot on regulated pressure response and large variations on inlet pressure are also given.

ISO 6953-3:2012 applies to the following components:

• compressed air pressure regulators and filter-regulators according to ISO 6953-1;
• electro-pneumatic pressure control valves according to ISO 10094;
• other components such as relief valves.