@PensFan:
Yes, there are issues of performing these calculations at the room level. There are ways around this but I have simply found the best has been to use an occupancy schedule at the room level and then to perform required plumbing calculations to break it out into an independent family. See http://bimproductivity.com/?wpsc-product=ibc-2006-minimum-plumbing-facilities
This is my family that I developed and have offered for sale and use. It has a number of advantages over the schedules in Revit as all of the required occupancies have been nested into one simple to use family.
