Space, Confined : A space whose volume is less than 1. 42 m3/293 W (50 ft3/1000 Btu/hr) of the aggregate input rating of all appliances installed in that space
NFPA 96 Standard for Ventilation Control and Fire Protection of Commercial Cooking Operations, 2008 ed. http://www.nfpa.org/codes-and-standards/document-i nformation-pages?mode=code&code=96, (Std: Vent Control and Fr Prac of Comm Cooking Opr - Amer) {240 NFC}