You would like to use the US database and define approriate density settings.
1. Open Revit and go to KeySCAPE>Project Setup
3. Next to Softworks Database, seelct the folder icon
4. The 'Select New Database' dialog appears, showing the name of the current database next to File name, typically 'KSW_Database.keydb'
4. In the main window, pick the database named 'KSW_Database_US Regionalization.keydb'
5. Pick Save
6. You should now be using the US database
7. Under 'Density Names', change the density suffix you would like to display when specifying plants, for example you may wish to use the abbreviation "O.C." when specifying centers
8. Once defined, either pick OK to apply the density changes to the current model only or 'SET TO DEFAULT' to apply your preferred density settings to all new drawings.created in KeySCAPE RT
Note: the database settings persist irrespective of your desnity prefernces. Also, you can export serveral desntiy preference settings and import these into other models, as required.