Ventilation systems in ammonia machinery rooms shall be operated continuously. In machinery rooms containing refrigeration equipment using Group 2 refrigerants, the inlet to the exhaust fan or fans, or air-duct connection, shall be located near the ceiling, and the outlet from the fan or fans, or air-duct connection, shall terminate outside the building above the roof of the highest story of the building, and shall be at least 30 feet (9.144 m) from any penthouse, skylight, or ventilation air-intake.