506.6 Exterior duct installations.
MC § 506.6
The installation of exterior ducts shall comply with the following requirements: 1. The exterior portion of the ductwork shall be vertical wherever possible and shall be installed and supported on the exterior of a building.
2.Bolts, screws, rivets, and other mechanical fasteners shall not penetrate duct walls.
3.Clearance of any ducts shall comply with Section 506.3.6.
4.All ducts shall be protected on the exterior by paint or other suitable weather-protective coating.
5.Ducts constructed of stainless steel shall not be required to have additional paint or weather-protective coatings.
6.Ductwork subject to corrosion shall have minimal contact with the building surface.
7.No portion of an exterior metal duct shall be nearer than 24 inches (609.6 mm) to any door or window or to any exit, or located where it would be readily accessible to the public, unless it is insulated or shielded to avoid injury to any person coming in contact with the duct. Exception: Listed and labeled factory-built commercial kitchen grease ducts may be used when installed in accordance with Section 304.1.
