To Size Duct

Select (Duct Sizer).
The Duct Sizer dialog opens.
Complete Duct Sizer settings, and click Calculate.
The result field displays alternate duct sizings in separate pane in the right.
Select a duct size from the result and click Place Duct.
Move the cursor in the drawing view and click to select the data point to place the selected duct element.
Click Close to dismiss the dialog.