A Side Discharge Orifice (SDO) represents an orifice in the pipeline where flow enters or exits the pipeline based on the pressure at that location. The orifice can discharge into the atmosphere, a fixed head region, or an open or closed surge tank. Applications include valve venting to atmosphere or fixed head region, blow off valve, line rupture, and flow exit through any resistance device into a constant head region. The inflow and outflow resistances can be different (inflow refers to flow into the pipeline and outflow is out of the pipeline). This device also is an integral part of a number of surge control devices including open and closed surge tanks, feed tanks, pressure relief valves, air release (vacuum) valves, and surge anticipation valves.

Disable This Surge Protection Device

If this box is checked, then the selected SPD will not be modeled in the Surge analysis.

Device Type

Type of Surge Protection Device to be used.

Side Discharge Orifice  Input Data

  • Inflow Resistance - This specifies the amount of resistance to flow into the system (pipe).

  • Outflow Resistance - This specifies the amount of resistance to flow out of the system (pipe).

  • External  Pressure - This field is the external pressure next to the pipe. A value of 0 means exiting to the atmosphere. The Pressure unit is set in the Simulation Options. 

Purge - Use the Purge button to remove existing Data.

Create/Update - Enter new or changed data and exit the dialog box.

Cancel - Cancels any new or changed data and closes the dialog box.