Height 3 : As applied to a building, the vertical distance from the adjacent ground elevation to the average elevation of the roof of the highest story.
NFPA 1141 Standard for Fire Protection in Planned Building Groups, 2003 ed. http://www.nfpa.org/assets/files/AboutTheCodes/114 1/1141-A2003-rop.PDF, (Std: Fr Prac in Plan Build Groups - Amer) {382 NFC}