304.3 Access to Appliances on Roofs
Not less than 6 feet (1829 mm) of clearance shall be between the access opening and the edge of the roof or similar hazard or rigidly fixed rails or guards not less than 42 inches (1067 mm) in height shall be provided on the exposed side. Where parapets or other building structures are utilized in lieu of guards or rails, they shall be not less than 42 inches (1067 mm) in height. [NFPA 54:184.108.40.206]
- Side railings shall extend not less than 30 inches (762 mm) above the roof or parapet wall.
- Landings shall not exceed 18 feet (5486 mm) apart measured from the finished grade.
- Width shall be not less than 14 inches (356 mm) on center.
- Rungs spacing shall not exceed 12 inches (305 mm) on center, and each rung shall be capable of supporting a 300 pound (136.1 kg) load.
- Toe space shall be not less than 6 inches (152 mm).