18-29-904.2 Frost closure.
   Every vent extension through a roof or wall shall be a minimum of 4 inches (100 mm) in diameter. Any increase in the size of the vent shall be made a minimum of 1 foot (305 mm) inside the thermal envelope of the building.
(Amend Coun. J. 10-14-21, p. 37722, Art. IX, § 3)