Minnesota Administrative Rules

1323.0402 SECTION C402, BUILDING ENVELOPE REQUIREMENTS.

Subpart 1.

IECC section C402.2.1.2 Insulation requirements for roof replacement.

IECC section C402.2.1 is amended by adding a new subsection C402.2.1.2 to read as follows:

C402.2.1.2 Insulation requirements for roof replacement. For roof replacement on an existing building where the insulation is entirely above the deck and where the roof slope is less than two units vertical in 12 units horizontal, the insulation shall conform to the energy conservation requirements specified in Table C402.2, Opaque Thermal Envelope Requirements.

Exception: Where the required R-value cannot be provided because of the thickness limitations that occur with the existing rooftop conditions, including heating, ventilation and air-conditioning equipment, low door or glazing heights, parapet heights, or proper roof flashing heights, the maximum thickness of insulation compatible with the available space and existing rooftop conditions shall be installed.

Subp. 2.

IECC section C402.4.1.1 Air barrier construction.

IECC section C402.4.1.1 is amended to read as follows:

C402.4.1.1 Air barrier construction. The continuous air barrier shall be constructed to comply with the following:

1. The air barrier shall be continuous for all assemblies that are the thermal envelope of the building and across the joints and assemblies.

2. Air barrier joints and seams shall be sealed, including sealing transitions in places and changes in materials. Air barrier penetrations shall be sealed in accordance with section C402.4.2. The joints and seals shall be securely installed in or on the joint for its entire length so as not to dislodge, loosen, or otherwise impair its ability to resist positive and negative pressure from wind, stack effect, and mechanical ventilation.

3. Recessed lighting fixtures shall comply with section C402.4.8. Where similar objects are installed that penetrate the air barrier, provisions shall be made to maintain the integrity of the air barrier.

Subp. 3.

Section C402.4.5.1 Stairway and shaft vents.

IECC section C402.4.5.1 is amended to read as follows:

C402.4.5.1 Stairway and shaft vents. Stairway and shaft vents shall be provided with Class I motorized dampers with a maximum leakage rate of 4 cfm/ft² (20.3 L/s·m²) at 1.0 inch water gauge (w.g.) (249 Pa) when tested in accordance with AMCA 500D.

Controls for operating stairway and shaft vents shall be provided in accordance with Minnesota Rules, chapter 1305.

(Items 1 and 2 of this subsection are deleted.)

Subp. 4.

IECC section C402.4.5.2 Outdoor air intakes and exhausts.

IECC section C402.4.5.2 is amended to read as follows:

C402.4.5.2 Outdoor air intakes and exhausts. Outdoor air supply and exhaust openings shall be provided with Class IA motorized dampers with a maximum leakage rate of 4 cfm/ft² (20.3 L/s·m²) at 1.0 inch water gauge (w.g.) (249 Pa) when tested in accordance with AMCA 500D.

Exceptions:

1. For exhaust and relief dampers in buildings less than three stories in height above grade plane or, where the design outdoor air intake or exhaust capacity does not exceed 300 cfm, (141 L/s), gravity (nonmotorized) dampers having a maximum leakage rate of 20 cfm/ft²(101.6 L/s m²) at 1.0-inch water gauge) (w.g.) (249 Pa) when tested in accordance with AMCA 500D are permitted to be used.

Gravity (nonmotorized) dampers for ventilation air intakes shall be protected from direct exposure to wind.

2. Nonmotorized dampers smaller than 24 inches (610 mm) in either dimension shall be permitted to have a leakage of 40 cfm/ft² (203.2 L/s·m²) at 1.0 inch water gauge (w.g.) (249 Pa) when tested in accordance with AMCA 500D.

3. Dampers for exhaust ducts 8 inches (203 mm) in diameter and smaller shall be permitted without being tested in accordance with AMCA 500D if equipped with a spring-loaded backdraft damper and a weather hood at the point of discharge.

Statutory Authority:

MS s 326B.02; 326B.101; 326B.106

History:

39 SR 1616

Published Electronically:

June 8, 2015