Code issues affecting standby generator sets

NFPA 37   2002 Edition

6.3.2 Fuel Tanks Inside Structures. 

6.3.2.1 Fuel tanks inside structures shall be securely mounted on noncombustible supports.

6.3.2.2*  Fuel tanks not in a room by themselves shall not exceed 2500 L (660 gals). Fuel tanks larger than 2500 L (660 gals) capacity shall be enclosed in a room in accordance with 6.3.5 or 6.3.6. Not more than one such 2500 L (660 gals) capacity tank, or two or more of these tanks with an aggregate capacity of not more than 2500 L (660 gals), shall be connected to one engine.

Exception:  Fuel tanks of any size shall be permitted within engine rooms or mechanical spaces, provided the engine or mechanical room is designed using recognized engineering practices with suitable fire detection, fire suppression, and containment means to prevent the spread of fire beyond the room of origin.

6.3.2.3*  The aggregate capacity of all fuel tanks in a structure shall not exceed 5000 L (1320 gal) unless that portion exceeding 5000 L (1320 gal) is enclosed in a room in accordance with 6.3.5 or 6.3.6.

Exception:  Fuel tanks of any size shall be permitted within engine rooms or mechanical spaces provided the engine or mechanical room is designed using recognized engineering practices with suitable fire detection, fire suppression, and containment means to prevent the spread of fire beyond the room of origin.

6.3.5 Rooms Housing Only Fuel Tanks with an Aggregate Capacity of 5000 L (1320 gal) or Less.

6.3.5.1 Rooms containing only fuel tanks with an aggregate capacity of 5000 L (1320 gal) or less shall be constructed of walls, floor, and ceiling having a fire-resistance rating of not less than 1 hour with the walls bonded to the floor.

6.6.3.6 Rooms Housing Only Fuel Tanks with an Aggregate Capacity of More Than 5000 L (1320 gal).

6.3.6.1 Rooms containing only fuel tanks shall be constructed of walls, floor, and ceiling having a fire-resistance rating of not less than 3 hours with the walls bonded to the floor.