Locker Rooms

Is a Locker Room considered a suite?

No, a Locker Room would not be classified as a suite because it is not considered a "habitable room" due to it only being briefly occupied.
 
NFPA 101 - 2009 Life Safety Code Handbook
Chapter 19 
A.19.2.5.6.1  For the purposes of this paragraph, it is the intent that "habitable rooms" not include individual bathrooms, closets, and similar spaces, as well as briefly occupied work spaces, such as control rooms in radiology and small storage rooms in a pharmacy.