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. All access locks, screws, and bolts shall be of corrosion-resistant material. [NFPA 54:9.4.1.3] 303.8.3 Installation of Appliances on Roofs. Appliances shall be installed in accordance with the manufacturer’s installation instructions. [NFPA 54:9.4.2.1] 303.8.4 Edge of Roof 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]

303.8.4.1 Guards and Rails. Guards or rails shall be required where the following exist: (1) The clearance between the appliance and a roof

edge or open end of an equipment platform is less than 6 feet (1829 mm). (2) The open end of the equipment platform is

located more than 30 inches (762 mm) above the roof, floor, or grade below.

GENERAL REGULATIONS

Where guards or rails are installed, they shall be constructed so as to prevent the passage of a 21 inch (533 mm) diameter ball, resist the imposed loading conditions, and shall extend not less than 30 inches (762 mm) beyond each side of the equipment or appliance. Exception: Guards shall not be required where a permanent fall arrest anchorage connector system in accordance with ASSE Z359.1 is installed. 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 deenergizes the appliance. (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 water line. 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]