Drafting with Flow Direction

Flow direction is the forward movement of a material or fluid (such as air or water) through the components of a system. You can set or reverse the flow direction of a duct run or a pipe run between 2 branches. Once you set the flow direction, you can show it using flow markers, toggling the markers on and off as needed. The flow markers are solid 2D arrows displayed at the midpoint of segments.

Flow markers indicating the flow direction of a pipe run

NoteIn addition to flow markers, you can also add flow labels (sometimes referred to as flow arrows in the software) to duct runs and pipe runs. Like flow markers, flow labels show the current flow direction of the run if the flow direction has been set, and they are scaled according to the annotation scale. Unlike flow markers, flow labels are fully annotative objects, which means you can modify and delete them. For information on adding flow labels as you draw, see Applying Label or Flow Arrow Styles to Ducts or Adding Labels or Flow Arrows to Pipe.

To set or reverse the flow direction of a duct or pipe run

  1. Select a segment in the run.
  2. Click Duct tabCalculations panelSet Flow Direction .

You can perform the same operation on a pipe run using Set Flow Direction on the Pipe tab.

  1. The current flow direction of the run is shown by an arrow in the center of the selected segment. If the run does not have an assigned flow direction, the start point of the segment is considered upstream, and a default flow direction is shown.

  2. Do one of the following:
    • Enter y (yes) to reverse the flow direction.
    • Enter n (no) to accept the indicated flow direction.

    The selected run between branches is assigned the indicated flow direction. Flow direction for a run stops at branch fittings (fittings with 3 or more connectors, such as tees and crosses) and MvParts.

    NoteTo reverse the flow direction of a single segment, select it, right-click, and click ReverseSegment (or enter reversesegment).

To turn flow markers on or off for all runs that have a flow direction

  1. Select a segment in a run.
  2. Click Pipe tab or Duct tabCalculations panelShow Flow .
NoteIf you do not want flow markers to appear on construction documents, turn them off before plotting or publishing.