UpCodes logo
Go To Full Code Chapter
All supply and return ducts and plenums installed as part of an HVAC air distribution system shall be thermally insulated in accordance with Table 6.8.2.
Exceptions to 6.4.4.1.2
  1. Factory-installed plenums, casings, or ductwork furnished as a part of HVAC equipment tested and rated in accordance with Section 6.4.1.
  2. Ducts or plenums located in heated spaces, semiheated spaces, or cooled spaces.
  3. For runouts less than 10 ft in length to air terminals or air outlets, the rated R-value of insulation need not exceed R-3.5.
  4. Backs of air outlets and outlet plenums exposed to unconditioned space or indirectly conditioned space with face areas exceeding 5 ft2 need not exceed R-2; those 5 ft2 or smaller need not be insulated.

Related Code Sections

602.2.1.8 Duct Systems, Pipe and Duct Insulation Within Plenums
Pipe and duct insulation contained within plenums, including insulation adhesives, shall have a flame spread index of not more than 25 and a smoke ...
604.13 Duct Systems, Internal Insulation
Exposed internal insulation that is not impermeable to water shall not be used to line ducts or plenums from the exit of a cooling coil to the downstream ...
Chapter 16 Duct Systems
construction, duct installation, duct insulation properties, duct sealing, above-ground and underground ducts, return air intake locations and air ...