This test method describes how to determine two criteria used in selecting valves of appropriate size for gases and liquids.

Methods and equations are specified and/or referenced to assist in accurate calculation of pressure drops across valves tested by this method.

This method establishes the testing criteria for determination of two coefficients specified in ANSI/ISA-S75.02:

• Valve flow coefficient (C_v)
• Critical pressure drop ratio factor (x_T )

This method is to be used with ANSI/ISAS75.02. This method applies to manual and actuated valves for use in both gas and liquid distribution systems used in semiconductor manufacturing facilities. It is a test method, where existing test methods are referenced and limitations are imposed on test conditions. Specific equations for calculating flow coefficients, choked flow parameters, and pressure drops are referenced to the appropriate ISA section.

None.