ASHRAE-90.1-2022- - Page 069
Extracted Content
5.8.1.3 Loose-Fill Insulation Limitation. Open-blown or poured loose-fill insulation shall not be used in attic roof spaces when the slope of the ceiling is more than three in twelve.
5.8.1.4 Baffles. When eave vents are installed, baffling of the vent openings shall be provided to deflect the incoming air above the surface of the insulation.
5.8.1.5 Substantial Contact. Insulation shall be installed in a permanent manner in substantial contact with the inside surface in accordance with the manufacturer ’s recommendations for the framing system used. Flexible batt insulation installed in floor cavities shall be supported in a permanent manner by supports no greater than 24 in. on center.
Exception to 5.8.1.5: Insulation materials that rely on air spaces adjacent to reflective surfaces for their
rated performance.
5.8.1.6 Recessed Equipment. Lighting fixtures ; heating, ventilating, and air-conditioning equipment, including wall heaters, ducts, and plenums ; and other equipment shall not be recessed in such a manner as to affect the insulation thickness unless
a. the total combined area affected (including necessary clearances) is less than 1% of the opaque area of
the assembly, b. the entire roof, wall, or floor is covered with insulation to the full depth required, or c. the effects of reduced insulation are included in calculations using an area-weighted-average method and
compressed insulation values obtained from Table A9.4.3.
In all cases, air leakage through or around the recessed equipment to the conditioned space shall be limited in accordance with Section 5.4.3.
5.8.1.7 Insulation Protection. Exterior insulation shall be covered with a protective material to prevent damage from sunlight, moisture, landscaping operations, equipment maintenance, and wind.
5.8.1.7.1 In attics and mechanical rooms, a way to access equipment that prevents damaging or compressing the insulation shall be provided.
5.8.1.7.2 Foundation vents shall not interfere with the insulation. 5.8.1.7.3 Insulation materials in ground contact shall have a water absorption rate no greater than 0.3% when tested in accordance with ASTM C272.
5.8.1.8 Location of Roof Insulation. The roof insulation shall not be installed on a suspended ceiling with removable ceiling panels.
5.8.1.9 Extent of Insulation. Insulation shall extend over the full component area to the required rated R-value of insulation, U-factor, C-factor, or F-factor, unless otherwise allowed in Section 5.8.1.
5.8.1.10 Joints in Rigid Insulation. Where two or more layers of rigid insulation board are used in a construction assembly, the edge joints between each layer of boards shall be staggered.
5.8.2.1 Rating of Fenestration Products. The U-factor, SHGC, VT, and air leakage rate for all manufactured fenestration products shall be determined by a laboratory accredited by a nationally recognized accreditation organization, such as the National Fenestration Rating Council.
5.8.2.2 Labeling of Fenestration and Door Products. All manufactured and site -built fenestration and
Exception to 5.8.2.2: Doors with less than 25% glazing are not required to list SHGC and VT .
5.8.2.3 Manufacturer’s Installation Instructions. Fenestration products shall be installed in accordance with manufacturer ’s instructions.
5.8.2.4 U-Factor. U-factors shall be determined in accordance with NFRC 100. U-factors for skylights shall be determined for a slope of 20 degrees above the horizontal.
Exceptions to 5.8.2.4:
- U-factors from Section A8.1 shall be an acceptable alternative for determining compliance with the U-factor criteria for skylights . Where credit is being taken for a low-emissivity coating, the emissivity of the coating shall be determined in accordance with NFRC 300. Emissivity shall be verified and certified by the manufacturer .
ANSI/ASHRAE/IES Standard 90.1-2022 (I-P) 67
