Revit MEP: Elbows for Engineers - Part I

Alan Jackson bio photo By Alan Jackson Comment

The default Revit MEP content provided in the Mechanical Template is pretty horrendous. Here is a quick way to get up and running with some long and short radius Steel Sch 40 pipe and Duct Elbows with a more SMACNA standard throat.

Pipe Type Settings

The “Standard” pipe type provided out of the box is intended to represent Copper Type K with brazed fittings. Commonly used pipe for Mechanical Systems or at least one to standardize around for piping layouts is a Steel Sch 40. The easiest way to implement this is to duplicate the Standard pipe type provided and change the material, connection and class type properties. (See image on right)

That’s the easy part. Now for the elbows we are going to utilize the following (2) lookup tables which Revit MEP uses for pipe fitting definitions and dimensions. The files need to reside in your default lookup tables folder either locally or deployed on your network. The local file location on Windows 7 is C:\ProgramData\Autodesk\RME\2012\LookupTables\Pipe

File format must be .csv (comma separated). Restart Revit if its already loaded when you do this.

Specify Lookup Table

Now we can edit the lookup table that the elbow uses directly from within the project. Doing this prevents the warnings you get if trying to edit lookup tables in the family editor. Duplicate the generic elbow family by saving it under a new name and loading it into the project. Go to the type properties of the newly created elbow and change the lookup table .csv name to one of the examples above (double check spelling, it must match file name exactly!). I will use the Long Radius for this example so you would paste Elbow_Long_Radius-Welded-Sch_40.csv into the parameter box. Now fire that new elbow up in the family editor and modify the following parameter equations to match.

Fitting Outside Diameter = 

text_file_lookup(Lookup Table Name, "PipeOD", Nominal Diameter + 0'  0 1/8", Nominal Diameter)

Center Radius =

text_file_lookup(Lookup Table Name, "CRad", Nominal Diameter * 1.5, Nominal Diameter)

That’s it! Load the family back into the project, be sure to accept the Override Existing Family and Parameters option since we updated the parameter values. Now you can use that elbow type in your newly created pipe type.I’ll let you guys figure out how to update the rest of the fittings, otherwise its no fun. Good Luck!

Parameter Equations
Change Pipe Elbow Type

In Part II I will discuss the Duct Fitting Elbow and how to spruce that up a bit. Check back soon!

Befor and After