5.5.3 Opaque Areas
- Minimum rated R-value of insulation for the thermal resistance of the added insulation in framing cavities and continuous insulation only. Specifications listed in Normative Appendix A for each class of construction shall be used to determine compliance.
- Maximum U-factor, C-factor, or F-factor for the entire assembly. The values for typical construction assemblies listed in Normative Appendix A shall be used to determine compliance.
Roofs in Climate Zones 0 through 3 shall have one of the following:
- A minimum three-year-aged solar reflectance of 0.55 and a minimum three-year-aged thermal emittance of 0.75 when tested in accordance with CRRC-1 Standard.
- A minimum Solar Reflectance Index of 64 when determined in accordance with the Solar Reflectance Index method in ASTM El980 using a convection coefficient of 2.1 Btu/h•ft2•°F, based on three-year-aged solar reflectance and three-year-aged thermal emittance tested in accordance with CRRC-1 Standard.
- Increased roof insulation levels found in Table 22.214.171.124.1.
|Opaque Elements||Assembly Maximum||Insulation Min. R-Value||Assembly Maximum||Insulation Min. R-Value|
|Climate Zone 0|
|Insulation entirely above deck||U-0.027||R-36 c.i.||U-0.027||R-36 c.i.|
|Climate Zones 1 to 3|
|Insulation entirely above deck||U-0.030||R-33 c.i.||U-0.029||R-34 c.i.|
The values for three-year-aged solar reflectance and three-year-aged thermal emittance shall be determined by a laboratory accredited by a nationally recognized accreditation organization and shall be labeled and certified by the manufacturer.
- If insulated on the interior, the wall shall be insulated to the above-grade wall requirements.
- 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.
In addition, for Climate Zone 0, above-grade walls shall comply with one of the following:
- For east and west walls, a minimum of 75% of the opaque wall area shall have a minimum SRI of 29. For the portion of the opaque wall that is glass spandrel area, a minimum solar reflectance of 29% determined in accordance with NFRC 300 or ISO 9050 shall be permitted. Each wall is allowed to be considered separately.
- For east and west walls, a minimum of 30% of the above-grade wall area shall be shaded through the use of shade-providing plants, manmade structures, existing buildings, hillsides, permanent building projections, on-site renewable energy systems, or a combination of these. Shade coverage shall be calculated at 10 a.m. for the east walls and 3 p.m. for the west walls on the summer solstice.
The building is allowed to be rotated up to 45 degrees to the nearest cardinal orientation for purposes of calculations and showing compliance.