When masonry chimneys are constructed as part of masonry or concrete walls, combustible materials shall not be in contact with the masonry or concrete wall less than 12 inches (306 mm) from the inside surface of the nearest flue lining.ģ. Masonry chimneys equipped with a chimney lining system listed and labeled for use in chimneys in contact with combustibles in accordance with UL 1777 and installed in accordance with the manufacturers installation instructions are permitted to have combustible material in contact with their exterior surfaces.Ģ. The air space shall not be filled, except to provide fire blocking in accordance with Section R1001.16.ġ. Chimneys located entirely outside the exterior walls of the building, including chimneys that pass through the soffit or cornice, shall have a minimum air space clearance of 1 inch (25.4 mm).
Any portion of a masonry chimney located in the interior of the building or within the exterior wall of the building shall have a minimumair space clearance to combustibles of 2 inches (51 mm).
