303.8 Appliances on Roofs. Appliances on roofs shall be

designed or enclosed so as to withstand climatic conditions in the area in which they are installed. Where enclosures are provided, each enclosure shall permit easy entry and movement, shall be of reasonable height, and shall have at least a 30 inch (762 mm) clearance between the entire service access panel(s) of the appliance and the wall of the enclosure. [NFPA 54:9.4.1.1] 303.8.1 Load Capacity. Roofs on which appliances are to be installed shall be capable of supporting the additional load or shall be reinforced to support the additional load. [NFPA 54:9.4.1.2] 303.8.2 Fasteners. Access locks, screws, and bolts shall be of corrosion-resistant material. [NFPA 54:9.4.1.3] Appliances shall be installed in accordance with the man- 303.8.3 Installation of Appliances on Roofs. ufacturer’s installation instructions. [NFPA 54:9.4.2.1] 303.8.4 Clearance. Appliances shall be installed on a well-drained surface of the roof. At least 6 feet (1829 mm) of clearance shall be available between any part of

the appliance and the edge of a roof or similar hazard, or rigidly fixed rails, guards, parapets, or other building structures at least 42 inches (1067 mm) in height shall be provided on the exposed side. [NFPA 54:9.4.2.2] 303.8.5 Electrical Power. All appliances requiring an external source of electrical power for its operation shall be provided with the following: (1) A readily accessible electrical disconnecting means

within sight of the appliance that completely de

(1) A readily accessible electrical disconnecting means

within sight of the appliance that completely deenergizes the appliance. (2) A 120-V ac grounding-type receptacle outlet on the

roof adjacent to the appliance on the supply side of

(2) A 120-V ac grounding-type receptacle outlet on the

roof adjacent to the appliance on the supply side of the disconnect switch. [NFPA 54:9.4.2.3] 303.8.6 Platform or Walkway. Where water stands on the roof at the appliance or in the passageways to the appliance, or where the roof is of a design having a water seal, a suitable platform, walkway, or both shall be provided above the waterline. Such platform(s) or walkway(s) shall be located adjacent to the appliance and control panels so that the appliance can be safely serviced where water stands on the roof. [NFPA 54:9.4.2.4]