Minnesota Administrative Rules

1346.0604 SECTION 604 INSULATION.

IMC Section 604.1 is amended to read as follows:

604.1 General. Duct insulation shall conform to the thickness required by this section and Sections 604.2 through 604.13.

Exception: Except as required to prevent condensation, ducts for which heat gain or loss, without insulation, will not increase the energy requirements of the building.

Minimum Required Duct Insulation (see notes for explanations)

Duct Location	Requirements
Attics, garages, and ventilated crawl spaces	R-8 and V
Exterior of building	R-8, V and W
Inside of building and in unconditioned spaces
TD less than or equal to 15°F	None required
TD greater than 15°F and less than or equal to 40°F	R-3.3 and V
TD greater than 40°F	R-5 and V
Within conditioned spaces, in basements with insulated walls, and in plenums within conditioned spaces	None required
Intake and exhaust ducts within conditioned spaces*	R-3.3 and V
Within cement slab or within ground (also see IMC Section 603.7)	R-3.5

Notes:

^*Insulation required for a distance of 3 feet (914 mm) from the exterior.

TD = Design temperature differential between the air in the duct and the ambient temperature outside of the duct.

V = Vapor retarder required in accordance with IMC Section 604.11. When a vapor retarder is required, duct insulation required by this section shall be installed without respect to other building envelope insulation.

W = Approved weatherproof barrier.

Statutory Authority:

MS s 16B.59; 16B.61; 16B.64; 326B.101; 326B.106; 326B.13

History:

15 SR 71; 29 SR 299; L 2007 c 140 art 4 s 61; art 13 s 4; 34 SR 537

Published Electronically:

October 23, 2009