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Calculating Pressure Drop

This tutorial teaches you how to calculate and adjust for pressure drop in your ductwork.

Open drawing M-1.0.

Insert the Pressure Drop Report​

  1. Run the Insert Duct Pressure Drop Report command.
    Ribbon: DM HVAC→Ducts→  Insert Duct Pressure Drop Report
    Pulldown Menu: DM HVAC→Calculations→Insert Duct Pressure Drop Report

  2. Select a duct in the system. The Insert Duct Pressure Drop Report dialog box will open.

  3. Make sure ☐ Calculate Pressure Drop is checked.

  4. Uncheck the ☐ Draw Ductwork box.

  5. Press the button to close the dialog box.

  6. Follow the prompts at the command line to insert the pressure drop report on the drawing.

The critical run in the system will be highlighted. ID tags will be assigned to each duct in the critical run, which correspond to the ID column of the pressure drop report.

Update the Pressure Drop Report​

  1. Run the Reset to Automatic Fitting command.
    Ribbon: DM HVAC→Ducts→  Reset to Automatic Fitting
    Pulldown Menu: DM HVAC→Fittings→Reset to Automatic Fitting

  2. Select a duct near the radius elbow in the long copy room. The radius elbow will be changed to a square elbow.

  3. Run the Insert Duct Pressure Drop Report command.
    Ribbon: DM HVAC→Ducts→  Insert Duct Pressure Drop Report
    Pulldown Menu: DM HVAC→Calculations→Insert Duct Pressure Drop Report

  4. Select a duct in the system. The Insert Duct Pressure Drop Report dialog box will open.

  5. Press the button to close the dialog box.

The pressure drop report will be updated in its current location on the drawing.

Modify the Appearance of the Pressure Drop Report​

  1. Run the Insert Duct Pressure Drop Report command.
    Ribbon: DM HVAC→Ducts→  Insert Duct Pressure Drop Report
    Pulldown Menu: DM HVAC→Calculations→Insert Duct Pressure Drop Report

  2. Select a duct in the system. The Insert Duct Pressure Drop Report dialog box will open.

  3. Press the button. The Duct Pressure Drop Report Label Display and Order dialog box will open.

    note

    You may need to resize the dialog box so you can see the whole ☐ Display column.

  4. In the Duct ID row, set the Label to DUCT ID.

  5. In the Velocity row, uncheck the ☐ Display box.

  6. Press the button to save the changes to the label settings.

  7. Uncheck the ☐ Calculate Pressure Drop box.

  8. Press the button to close the dialog box.

The pressure drop report will be updated in its current location on the drawing.