Promulgated by the International Code Council (ICC), this national code applies to one and two family dwellings and townhouses up to three stories and limited by glazing area. It consists of a comprehensive collection of basic minimum construction regulations, containing prescriptive provisions ranging from structural and fire safety to electrical, plumbing, mechanical, and energy conservation. Chapter 16, Duct Systems, covers HVAC duct construction and acceptable duct materials, including fibrous glass insulation as covered in this guide.

Section N1 103.3 of this code contains the following duct insulation requirements: "All portions of the air distribution system ... shall be insulated to an installed R-5 when system components are located within the building but outside of conditioned space, and R-8 when located outside of the building. When located within a building envelope assembly, at least R-8 shall be applied between the duct and that portion of the assembly furthest from conditioned space. Exceptions: Exhaust air ducts and portions of the air distribution system within appliances or equipment."