Net Assignable Square Feet (NASF)
NASF is the sum of all areas on all floors of a building assigned to, or available for assignment to, an occupant or specific use. Assignable area is computed by physically measuring or scaling measurements from the inside faces of surfaces that form the boundaries of the designated areas. Exclude areas having less than a 3-foot clear ceiling height unless the criteria of a separate structure are met.
Totals include the major room use categories, classrooms, labs, offices, study facilities, special use, general use, support, health care, residential and unclassified spaces
Reference Postsecondary Education Facilities Inventory and Classification Manual (FICM) for more details. http://nces.ed.gov/pubsearch/pubsinfo.asp?pubid=2006160