Valve Sizing Toolbox Tab
An EES Tab is available that implements the detailed sizing relations laid out in ANSI/ISA-75.01.01 (IEC 60534-2-1 Mod)-2007, "Flow Equations for Sizing Control Valves" to determine the valve coefficients (C_v and K_v) for a valve given the flow conditions, geometry, valve type, pressure drop and required flow rate for both compressible and incompressible flow. A simpler method is also available in the tab. The EES tab is an alternate way of accessing the functions ValveCoef_Inc_ISA75_CL and ValveCoef_Comp_ISA75_CL. Provided you have a professional version of EES you can add the tab to your EES program Open Tab from the drop down menu that appears when you right-click on a tab.
The .eestab and related files can be downloaded from the ToolBox Tabs page on the fchart website and selecting Sizing Routine for Valves.