Revit Instructions:

The Revit files are made available in zip format.  They must first be unzipped into a directory such that both the RFA and TXT file are in the same location.  At that point perform a 'load family' and select the RFA file.  You'll then be presented with a dialog box of all the available sizes. Once the desired size(s) have been selected, the models will be listed under 'Pipe Accessories'.