Information required for sizing control valve is as follows
- Inlet pressure all possible cases
- Outlet pressure (or pressure drop) all possible cases
- Inlet temperature all possible cases
- Mass Flowrate all possible cases
- Solids content and size
- Critical temperature and critical pressure
- Allowable shutoff differential pressure
- For liquid service
- Vapor pressure
- Density
- Viscosity
- Surface tension
- For gas service
- Molecular weight
- Compressibility factor at the inlet and outlet conditions
- Cp/Cv ratio
- Dew point temperature
- Multiphase service
| Gas Properties | Liquid Properties |
| Molecular weight | Vapor pressure |
| Compressibility factor at the inlet and outlet conditions | Density |
| Cp/Cv ratio | Viscosity |
| Dew point temperature | Surface tension |
- Expected valve characteristics
- Design pressure or pressure rating of connecting system
- Deign Temperature
- Body size (connecting flange rating)
- Allowable noise level
- Actuator/Air/gas fail status
