Where combustion air is obtained from an attic area, the attic ventilating openings shall not be subject to ice or snow blockage, and the attic shall have not less than 30 inches (762 mm) vertical clear height at its maximum point. Attic ventilation openings shall be sufficient to provide the required volume of combustion air and the attic ventilation required by the Chicago Building Code. The combustion air openings shall be provided with a sleeve of not less than 0.019 inch (0.5 mm) (No. 26 Gauge) galvanized steel or other approved material extending from the appliance enclosure to at least 6 inches (152 mm) above the top of the ceiling joists and insulation.
(Amend Coun. J. 9-14-21, p. 35949, Art. VII, § 1)