Adjacent Ground Elevation : The reference plane representing the average elevation of the finished ground level measured at a distance of 3 m (10 ft) from all exterior walls of the building
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}