View and modify the instance properties for duct.
| Parameter | Description |
|---|---|
| Mechanical | |
| System Classification |
Defines the system for the connectors that are located on equipment. For example, piping equipment could have a system classification of Supply Air, Return Air, or Exhaust Air. These values are pre-defined classifications within Revit. |
| System Type |
Defines the system types for an MEP system. You can duplicate an existing system type to create additional system types as needed for the model. For example, if you need a system type for high pressure supply air, duplicate the Supply Air system type, rename it, and change the properties as needed. |
| System Name | A name that uniquely identifies a system, it may be user-defined or automatically generated. |
| System Abbreviation | A user-defined abbreviation for a system. |
| Equivalent Diameter | For rectangular duct, see About Rectangular. |
| Size Lock | When enabled, the duct will not resize when using the sizing tool. |
| Loss Coefficient | Displays the unitless number used to measure the minor loss for the selected duct or connector. Used to calculate the total pressure drop. |
| Hydraulic Diameter | See About Rectangular Duct. |
| Loss Method | Defines the loss method for the selected fitting. |
| Section | Defines a run of segments and fittings that have the same velocity, for example, the same flow, size, and shape. |
| Area | Defines the surface area of pipes, ducts, conduits, and cable trays. |
| Mechanical - Flow | |
| Flow | Displays the flow rate for the duct or duct connector. |
| Additional Flow | Defines the additional flow for the selected duct. |
| Velocity | This value is calculated using the following formula:
 |
| Friction | The pressure loss for a specific length unit of duct. |
| Pressure Drop | Displays the pressure drop for the selected duct, fitting, or connector. To see the pressure drop for each path through the fitting, check the pressure loss report. |
| Velocity Pressure | Displays the different between the total pressure and static pressure for the selected duct. |
| Reynolds Number | This value is calculated using the following formula:
 |