Drawing Ductwork

You can draw ductwork in various sizes and shapes. You can automatically place fittings, such as elbows and tees, as you draft. You can also manually add fittings to your runs, which is beneficial when using fittings not specified in the duct layout preferences.

NoteWhen you add duct runs, AutoCAD MEP inserts rise symbols and drop symbols as needed based on the rise/drop style assigned to the system of the run.

After you initially lay out your mechanical equipment, you can draw ductwork to connect equipment and create networks. AutoCAD MEP includes many features that streamline the design and drawing of duct runs.

The process for adding duct runs is the same. You can add duct as 1-line objects as you design preliminary routes, and then modify them to 2-line objects as you specify properties, such as size and connection type. 1-line duct runs appear as single-line representations while 2-line runs display the actual geometry of the duct, even in isometric views. You do not necessarily need to draw runs as 1-line elements at first. You can draw defined 2-line duct any time.

Note1-line duct objects differ from schematic lines in that they act as placeholders for sized 2-line duct objects. You can convert 1-line duct objects directly to 2-line duct objects of specific size and shape. For more information, see Display Representations

On the left, a top view of a 1-line duct run and on the right, a defined 2-line duct run.

You can draw duct runs in all 3 dimensions. You can also add sloped runs by specifying rise/run values. As you draw duct runs, fittings are automatically inserted to accommodate your routing geometry. The layout preferences specify which fittings are used. For more information, see Configuring Duct Routing Preferences.

1-line and 2-line duct runs can be routed 3 dimensions.

You can size duct systems using AutoCAD MEP engineering analysis tools. You can use a duct system size calculator to size duct systems, and you can use instant duct size calculators in the Add dialog and Modify dialog to size individual segments.