Rack, Multiple-Row : Racks greater than 12 ft (3. 7 m) wide or single- or double-row racks separated by aisles less than 3. 5 ft (1. 1 m) wide having an overall width greater than 12 ft (3. 7 m)
NFPA 230 Standard for the Fire Protection of Storage 1999 ed. http://www.nfpa.org/assets/files/aboutthecodes/230 /230-f2002-rop.pdf, (Std: Fr Prac of Storage - Amer) {267 NFC}