ASHRAE-90.1-2022- - Page 059
Extracted Content
5.5.3.2 Above-Grade Walls. Above-grade walls shall comply with the insulation values specified in Tables 5.5-0 through 5.5-8. For the purposes of this provision, wall plates, tracks, headers, or bond beams are considered part of the base wall assembly.
Exception to 5.5.3.2: For mass walls, where the requirement in Tables 5.5-0 through 5.5-8 is for a max imum assembly U-0.151 followed by footnote “b,” concrete masonry unit (CMU) walls complying with ASTM C90 that are ungrouted or partially grouted at 32 in. or greater on center vertically and 48 in. or greater on center horizontally, shall have their ungrouted openings (e.g., cores, cells) filled with insulating material having a maximum thermal conductivity of 0.44 Btu·in./h·ft [2] ·°F.
5.5.3.2.1 Walls That Are Both Above and Below Grade. W hen a wall consists of both above-grade and below - grade portions, the entire wall for that story shall be insulated on either the exterior or the interior or be integral.
a. If insulated on the interior, the wall shall be insulated to the above-grade wall requirements. b. If insulated on the exterior or integral, the below-grade wall portion shall be insulated to the below-grade
wall requirements, and the above-grade wall portion shall be insulated to the above-grade wall requirements.
a. A minimum of 75% of the opaque wall area shall have a minimum area-weighted initial solar reflectance
of 0.30 when tested in accordance with ASTM C1549 with AM1.5GV output, or ASTM E903 with the AM1.5GV output, or determined in accordance with generally accepted engineering standards, and a minimum emittance or emissivity of 0.75 when tested in accordance with ASTM C835, C1371, E408, or determined in accordance with generally accepted engineering standards. For the portion of the opaque wall that is glass spandrel area, a minimum solar reflectance of 0.29, determined in accordance with NFRC 300 or ISO 9050, shall be permitted. Area-weighting is permitted only between the south-, east-, and west-oriented walls and only between walls of the same space conditioning category . b. A minimum of 30% of the above-grade wall area shall be shaded through the use of human-made struc-
tures, existing buildings, hillsides, permanent building projections, on-site renewable energy systems, or a combination of these. Shade coverage shall be calculated by projecting the shading surface downward on the wall at an angle of 45 degrees.
Exception to 5.5.3.2.2: Exterior walls of semiheated spaces .
5.5.3.2.3 Insulated Metal Panels. The U-factor of wall assemblies that include insulated metal panels shall not be greater than the U-factors of Tables 5.5-0 through 5.5-8 for the applicable class of construction . U-factors of insulated metal panels shall be determined in accordance with Section A9.4.7.
5.5.3.3 Below-Grade Wall Insulation. Below-grade walls shall have a rated R-value of insulation no less than the insulation values specified in Tables 5.5-0 through 5.5-8.
Exception to 5.5.3.3: Where framing, including metal and wood studs, is used, compliance shall be
based on the maximum assembly C-factor .
5.5.3.4 Floors
5.5.3.4.1 Floor Insulation. All floors shall comply with the insulation values specified in Tables 5.5-0 through 5.5-8.
5.5.3.4.2 Insulated Metal Panels. The U-factor of floor assemblies that include insulated metal pan- els shall not be greater than the U-factors of Tables 5.5-0 through 5.5-8 for the applicable class of construc- tion . U-factors of insulated metal panels shall be determined in accordance with Section A9.4.7.
5.5.3.5 Slabs-on-Grade. All slab-on-grade floors, including heated slab-on-grade floors and unheated slab-on-grade floors, shall comply with the insulation values specified in Tables 5.5-0 through 5.5-8.
5.5.3.6 Opaque Doors. All opaque doors shall have a U-factor not greater than that specified in Tables 5.5-0 through 5.5-8.
Exceptions to 5.5.3.6:
- For conditioned spaces, nonswinging doors that are horizontally hinged sectional doors with a single row of fenestration shall have an assembly U-factor less than or equal to 0.440 in Climate Zones 0 through 6 and less than or equal to 0.360 in Climate Zones 7 and 8, provided the fenes- tration area is at least 14% and no more than 25% of the total door area .
ANSI/ASHRAE/IES Standard 90.1-2022 (I-P) 57