Duplicate and modify a standard system type to create a custom system type.
This video demonstrates the following:
Revit MEP comes with standard system types. For example, for duct systems, Revit MEP includes system types for Supply Air, Return Air, and Exhaust Air. You can add system types as needed in your design. The Families section of the Project Browser lists the default system types for duct and piping systems, as well as any custom system types you create.
To create a custom system type, simply duplicate an existing system type and customize the type properties as needed. For example, to create a system type for High Pressure Supply Air, begin by selecting the Supply Air system type, then right-click, and click Duplicate. Next, rename the duplicate by right-clicking again and selecting Rename.
Now you're ready to customize the type parameters for the new system type. Right-click the system type, and click Type Properties. Now you can customize type properties such as graphical overrides and materials.
For the High-Pressure Supply Air system type, you might want to customize the system abbreviation, which is the prefix used in the system name. If you assign the High Pressure Supply Air system type to a duct segment, the abbreviation and system name display on the Properties palette.
You can customize the type properties for the default system types as well. For example, you might want to customize the line color for the default Supply Air system type. The duct systems in the current view are assigned to the Supply Air system type. You can use the same procedures to create and customize piping system types.