Best Practices for Steam Control Valve Installation
Step 7: Enlarge the Discharge Piping
Always expand the discharge steam line piping at least one pipe diameter. It is not uncommon to expand the discharge piping at least two or three pipe diameters. The expansion of the pipe reduces the valve outlet velocities thus prolonging the valve life. The valve manufacturer will provide the appropriate pipe size after the control valve. Always match the pipe size to the heat transfer inlet connection.
For example, assume a three inch control and with a heat transfer inlet connection of eight inches. For this scenario, the pipe size at the outlet of the steam control valve should be increased to eight inches. Muffling orifice plates can be used to reduce a high pressure drop across the steam valve and reduce velocities.