Revit duct elevation tag: show top, bottom, or centerline elevation on ducts

A duct elevation tag tells the installer how high a duct runs. On a coordination sheet it is the number a fitter checks before anything else, and a missing one earns an RFI. Revit stores several heights for each duct, so most of the work is choosing the one your standard wants and getting it onto the tag.

This guide takes the job in order. RayCAD is a Revit plugin that tags MEPF drawings, and each step notes where the work slows down and how RayCAD handles it.

Which elevation does a duct have?

A duct has more than one height.

• Top elevation. The height of the top of the duct.
• Bottom elevation. The height of the underside, often called bottom of duct.
• Middle elevation. The height of the centerline.
• Offset. The height of the centerline above the duct's reference level.

Select a duct and read these in the Properties palette. Your standard decides which one the sheet shows. Many offices dimension the bottom of a rectangular duct, because that is the clearance under the beam. Many dimension the centerline of a round duct.

Check the numbers on a test duct before you build anything on them. Users report that some elevation values can include the insulation wrap, so compare a tag value against the duct's own Top Elevation and Bottom Elevation parameters.

How do you add elevation to a duct tag?

1. Select a duct tag in the model and click Edit Family.
2. Save a copy under a new name, so the original stays intact.
3. Select the label and click Edit Label.
4. Add Bottom Elevation, Top Elevation, or Middle Elevation from the list of parameters.
5. Add a prefix such as BOD or TOD in the Prefix column so the reader knows which height it is.
6. Select the elevation and click the format button. Clear Use project settings if the elevation needs different units from the project.
7. Click Load into Project.
8. Place it with Annotate, Tag, Tag by Category, or select the ducts and pick the new type in the Type Selector.

How do you set the elevation units?

1. Go to Manage, then Project Units.
2. Choose the discipline that holds the elevation. Elevation values follow the project length units, so start with Common.
3. Click the format button, set the units, rounding, and symbol, and click OK.

Round to the nearest 5 or 10 mm if your standard writes 2700 instead of 2703. A tag label can override the project setting with its own format.

How do you show elevation with a Spot Elevation?

Use a Spot Elevation when you need the height at one point, such as a duct crossing a beam in a section.

1. Open the section or elevation view.
2. Go to Annotate, Dimension, Spot Elevation.
3. Click the duct. Move the cursor to where you want the symbol, then click again.
4. Select the spot elevation and, in Properties, check which elevation it displays, such as top or bottom.

Edit the spot elevation type to change the symbol, the text, the prefix, and whether it shows the top, the bottom, or both. Spot elevations are placed one at a time, so check the result on a test duct in your own version before you use it across a set.

How do you tag the elevation of a sloped duct?

A sloped duct has a different height at each end, so a single value is wrong for the whole duct.

• Tag each end. A tag at the high end and a tag at the low end state both heights.
• Use a Spot Elevation. It states the height at the point you click.
• Use the start and end values. If your version lists start and end elevations among the parameters, read those in the label.

Check which of these your version offers on a sloped test duct.

Where do duct elevation tags belong?

A duct elevation tag does its job when the reader finds it once per change.

• Put one at the start of each run.
• Put one after each step up or down.
• Skip the straight stretches where the elevation does not change.
• Keep tags off fittings and off each other.

What goes wrong with duct elevation tags?

How does RayCAD tag duct elevation end to end?

You pick the views. RayCAD reads the elevation from the model, decides where each tag goes, places it, and lists anything it could not place. You review the result. Click-saver plugins speed up each click, and you still decide and place every tag.

What should you check before you issue the sheet?

• Every run shows an elevation at its start and after each step.
• The tag reads the same datum on every sheet, such as bottom of duct.
• Elevations match the coordination model.
• Sloped ducts show both ends.

RayCAD works in Revit 2021 through 2027. Start the free trial, or ask us for a demo and we'll set it up with your team. The guide to duct size tags covers the size half of the same tag.