This part of ISO 6358 specifies a discharge test and a charge test as alternative methods for testing pneumatic fluid power components that use compressible fluids, i.e. gases, and that have internal flow passages that can be either fixed or variable in size to determine their flow-rate characteristics. However, this part of ISO 6358 does not apply to components whose flow coefficient is unstable during use, i.e. components that exhibit remarkable hysteretic behaviour (because they can contain flexible parts that deform under the flow) or that have an internal feedback phenomenon (such as regulators), or components that have a cracking pressure such as non-return (check) valves and quick-exhaust valves. In addition, it does not apply to components that exchange energy with the fluid during flow-rate measurement, e.g. cylinders, accumulators, etc. NOTE This part of ISO 6358 does not provide a method to determine if a component has hysteretic behaviour; ISO 6358-1 does provide such a method. Table 1 provides a summary of which parts of ISO 6358 can be applied to various components. The charge test cannot be performed on components that do not have downstream port connections. This part of ISO 6358 specifies requirements for the test installation, the test procedure, and the presentation of results. Evaluation of measurement uncertainties is described in Annex A. Requirements for a method to test the volume of an isothermal tank are given in Annex B. Guidance on the isothermal tank is given in Annex C. Requirements for a method to test isothermal performance are given in Annex D. Guidance on the equation for calculating characteristics is given in Annex E. Guidance on calculating flow-rate characteristics is given in Annex F.