From an e-mail I received:
I was collecting statistics about the university where I have been working since early August. The Physical Plant people sent me "gross floor area" and "net floor area." OK, so I showed my ignorance and asked what the difference was. The lady was kind enough to write:
(Taken right from my construction dictionary (bet you didn't know there was one of those!) :) Anyway...
Gross floor area - "The total area of all the floors of a building, including intermediately floored tiers, mezzanine, basements, etc., as measured from the exterior surfaces of the outside walls of the buildings".
Net floor area - "The occupied area of a building not including hallways, elevator shafts, stairways, toilets and wall thicknesses". >>
Maybe this is old hat to the rest of you (especially those involved in discussions about space planning and utilization at your own universities!), but I had no idea about this distinction. Here's hoping that it might be useful to somebody else.
This got me to thinking about how Census does this. So I went to the retail trade segment of the 2002 Economic Census, and went to the aptly named Miscellaneous Subjects. What does Census track? Why, it's "under-roof floor space". But the good folks at the Bureau do differentiate "total" space from "selling" space".