# Valves and Fitting Losses

You can calculate the pressure drop for a specified flow rate through any of the valves & fittings in the Standard Valve & Fitting table.  This feature is available for all PIPE-FLO users. The Standard valve & fitting table is used to calculate and install resistance coefficients into pipelines for a variety of common valves and fittings.  The Standard table includes the valves and fittings listed in Appendix A of Crane's Technical Paper #410 "Flow of Fluids Through Valves, Fittings, and Pipe".

The resistance coefficient K is calculated from the following relation:

Where:

• f = turbulent friction factor (calculated from clean commercial steel pipe)
• $//$ = equivalent length of a resistance to flow, in pipe diameters

You can also calculate the dP across any individual valve or fitting directly from the pipeline graph window in PIPE-FLO Professional 2009.

Steps to Calculate Valve Losses

1. Initiate a project with definitions for system units, pipe materials and fluid zones in the System Settings & Properties dialog box.
• If you do not have a design file already saved with these parameters, create a new one by creating a new system.  In the System Settings & Properties dialog box, specify the engineering units on the Units tab.  Specify the pipe materials on the Specifications tab.  And specify the fluids on the Fluids tab.
• After you have specified the above information, click OK to save the project settings and access the FLO-Sheet.
2. Draw a pipeline on the FLO-Sheet.
• Select the Drawing tool button .
• Click once on the FLO Sheet to start the pipeline.
• Drag the line over and double-click the end to complete the pipeline.

3. Design the pipeline..
• Click the Select tool button .
• Double-click on the pipeline.
• Choose your pipe Specification and Fluid zone from the drop-down lists.
• Specify a pipe Length and Size.
• Specify the connection Elevations as zero ft.
4. Install the Valve or an equivalent Fixed Resistance.
• Click the Valves & Fittings tab in the Pipeline dialog box.
• To install an isolation valve from Crane TP #410, click the Isolation Valve button .  Select and Add one of the valves.
• To install a check valve from Crane TP #410, click the Check Valve button .  Select and Add one of the valves.
• To install a fixed resistance, click the Other Resistance button .  Select Fixed K, Fixed Cv or Fixed Kv, specify the appropriate value, and then click the Add button.
5. Graph the pipeline and calculate the dP across the valve.
• Click back on the Pipe tab, or double-click on the pipeline if you already closed the dialog box..
• Click the Graph button .
• Specify the desired flow rate in the Flow field.
• Hit Enter on your keyboard to update the data.
• The pressure drop due to valves & fittings will be listed in the mL (minor losses) field.  See Figure 1.

Figure 1 - Pipeline Graph Window