About Duct Settings

When Duct Settings is selected, the right pane displays a set of parameters that are common to all the duct systems in a project.

The Conversion branch below Duct Settings let you define default parameters that are applied separately to supply, return, and exhaust duct systems in your project.

Duct settings, duct sizes, and duct types can be copied to another project using the Transfer Project Standards feature.

Common Duct Settings

The following parameters specify the default duct types, sizes, and settings:

Use Annot. Scale for Single Line Fittings:
Specifies whether duct fittings are drawn at the size specified by the Duct Fitting Annotation Size parameter. Changing this setting does not change the plotted size of components already placed in a project.
Duct Fitting Annotation Size:
Specifies the plotted size of fittings and accessories drawn in single-line views. This size is maintained regardless of the drawing scale.
Air Density:
This parameter is used in determining duct sizing and pressure drop.
Air Dynamic Viscosity:
This parameter is used in determining duct sizing.
Rectangular Duct Size Separator:
Specifies the symbol to be used in showing rectangular duct sizes. For example, when an x is used, a duct that is 12 inches high and 12 inches deep would be shown as 12” x 12”.
Rectangular Duct Size Suffix:
Specifies the symbol appended to the duct size for rectangular ducts.
Round Duct Size Prefix:
Specifies the symbol preceding the duct size for round ducts.
Round Duct Size Suffix:
Specifies the symbol appended to the duct size for round ducts.
Duct Connector Separator:
Specifies the symbol used to separate information between 2 different connectors.
Oval Duct Size Separator:
Specifies the symbol to be used in showing oval duct sizes. For example, when an x is used, a duct that is 12 inches high and 12 inches deep would be shown as 12” x 12”.
Oval Duct Size Suffix:
Specifies the symbol appended to the duct size for oval ducts.
Duct Rise / Drop Annotation Size
Specifies the plotted size of rise/drop annotation drawn in single-line views. this size is maintained regardless of the drawing scale.
Flat on Top:
Specifies the symbol used in a part fitting tag to indicate its eccentric offset in the plane that is not visible in the current view. The value is determined by the face that is closest to the view plane. The flow is assumed to be from the primary connector to the secondary connector of the part.
Flat On Bottom:
Specifies the symbol used in a part fitting tag to indicate its eccentric offset in the plane that is not visible in the current view. The value is determined by the face that is closest to the view plane. The flow is assumed to be from the primary connector to the secondary connector of the part.
Set Up From Top/Bottom:
Specifies the symbol used in a part fitting tag to indicate its eccentric offset in the plane that is not visible in the current view. The value is determined by the face that is closest to the view plane. The flow is assumed to be from the primary connector to the secondary connector of the part. Set Up is followed by the length of the offset.
Set Down from Top/Bottom:
Specifies the symbol used in a part fitting tag to indicate its eccentric offset in the plane that is not visible in the current view. The value is determined by the face that is closest to the view plane. The flow is assumed to be from the primary connector to the secondary connector of the part. Set Down is followed by the length of the offset.
Centerline:
Specifies the symbol used in a part fitting tag to indicate its eccentric offset in the plane that is not visible in the current view. The value is determined by the face that is closest to the view plane. The flow is assumed to be from the primary connector to the secondary connector of the part.

Angles

When Angles is selected, you can specify the fitting angle that Revit will use when adding or modifying duct.

Use any angle:
Allow Revit to use any angle supported by the fitting content.
Set an angle increment:
Specifies the angle increment that Revit should use to determine the angle values.
Use specific angles:
Enable or disable specific angles for Revit to use.

Note: When manually creating a layout using a limited set of angles, you may notice that the selection point will be respected and the bend angle may be different from the preview.

Conversion

When Conversion is selected, you can specify parameters that control the elevations, duct size, and other characteristics for the ductwork created for the Main and Branch segments when using the Generate Layout tool.

Note: The Conversion Settings are also available from the Settings button on the Options Bar when creating a routing solution for your system’s ductwork.

Main

You can specify the following default parameters for the main ducts in the each system classification (Exhaust Air, Supply Air, Return Air):

Duct Type:
This is the default duct type for main ductwork.
Offset:
This is the height of duct components above the current level.

Branch

You can specify the following default parameters for the branch ducts in the each system classification (Exhaust Air, Supply Air, Return Air):

Duct Type:
This the default duct type for branch ductwork.
Offset:
This is the height of duct components above the current level.
Flex Duct Type:
This is the default type for flexible duct for branch ductwork (Flex Duct Round : Flex - Round, or None).
Maximum Flex Duct Length:
This is the longest length of a flexible duct segment that can be used in routing solutions for branch ductwork.

Rectangular

When Rectangular is selected, the right panel lists rectangular duct sizes available for a project and shows which sizes can be specified from the Options Bar. Although only one value is used to specify duct size here, it can be applied to height, width, or both. The Delete Size button removes a selected size from the table. The New Size button opens the Duct Size dialog, where you can specify new duct sizes to be added to the project.

Oval

When Oval is selected, the right panel lists oval duct sizes available for a project and shows which sizes can be specified from the Options Bar. Although only one value is used to specify duct size here, it can be applied to height, width, or both. The Delete Size button removes a selected size from the table. The New Size button opens the Duct Size dialog, where you can specify new duct sizes to be added to the project.

Round

When Round is selected, the right panel lists round duct sizes available for a project and shows which sizes can be specified from the Options Bar. The Delete Size button removes a selected size from the table. The New Size button opens the Duct Size dialog, where you can specify new duct sizes to be added to the project.

You can select how size values will be used:

Use in Size Lists:
When selected for a specific duct size, the size appears in lists throughout Revit, including duct layout editor, duct modify editor, flex duct and flex duct modify editor. When cleared, the size does not appear in these lists.
Use in Sizing:
When selected for a specific duct size, Revit determines the duct size, based on calculated system air flow. When cleared, the size is not used by the sizing algorithm.

Calculation

When Calculation is selected, you can enable network based calculations and specify the method used when calculating duct pressure drop for straight segments.

On the Networks tab, click the checkbox to enable network based calculations for design parts so they are consistent with fabrication parts.

On the Pressure Drop tab, select a Calculation Method from the list. The options are: Altshul-Tsal Equation, Colebrook Equation, or Haaland Equation. The details of each calculation method are displayed in the description area.

Note: If third party calculation methods are available, they display in the drop-down list.