ASHRAE-90.1-2022- - Page 064
Extracted Content
Table 5.5.5.1.1-1 Additional Wall Insulation Required for Mass Walls with Insulation on the Interior or Integral at Intersections with Roof Edges and Parapets
| Climate Zone | R-Value Increase | U-factor % Decrease |
|---|---|---|
| 4 | R-1.0 | 8% |
| 5 | R-1.0 | 8% |
| 6 | R-1.5 | 10% |
| 7 | R-1.5 | 10% |
| 8 | R-2.5 | 14% |
Table 5.5.5.1.1-2 Additional Roof Insulation Required for Mass Walls with Insulation on the Interior or Integral at Intersections with Roof Edges and Parapets
| Climate Zone | R-Value Increase | U-factor % Decrease |
|---|---|---|
| 4 | R-7.0 | 24% |
| 5 | R-7.0 | 24% |
| 6 | R-7.0 | 26% |
| 7 | R-9.0 | 26% |
| 8 | R-9.0 | 26% |
c. Where a mass wall has interior insulation that represents more than 50% of the total wall insulation R-
value, the interior insulation shall extend to the underside of the roof deck, shall be permitted to be interrupted by framing members, and shall comply with one of the following:
- Additional insulation having a rated R-value of insulation not less than R-5 shall extend inward on the underside of the roof deck for not less than 2 ft and be permitted to be interrupted by roof framing members.
- Additional insulation having a rated R-value of insulation not less than R-5 shall be placed at the exterior of the roof edge and be located between the bottom plane of the roof insulation and the plane of the bottom of the roof assembly in contact with the exterior wall .
- The wall insulation values in Tables 5.5-0 through 5.5-8 shall be adjusted in accordance with Table 5.5.5.1.1-1.
- The roof insulation values in Tables 5.5-0 through 5.5-8 shall be adjusted in accordance with Table 5.5.5.1.1-2. Informative Note: See Informative Appendix K, Figure K-1.
5.5.5.1.2 Parapets. At roof edges with parapets, the exterior wall insulation shall comply with one or more of the following as applicable to the location of the insulation and wall assembly:
a. Where a wall has exterior continuous insulation, such insulation shall be applied to both vertical sides of
the parapet. Informative Note: See Informative Appendix K, Figure K-2(a). b. Where a wall has cavity or integral insulation that represents more than 50% of the total wall insulation
- The wall insulation shall extend within the cavity of the parapet not less than the height of the top of the roof insulation. The wall insulation shall be permitted to be interrupted by roof framing members.
- Additional insulation having a rated R-value of insulation not less than R-5 shall extend inward on the underside of the roof deck for not less than 2 ft and be permitted to be interrupted by roof framing members.
- Insulation having a rated R-value of insulation not less than R-5 shall be placed at the exterior of the roof edge and be located between the bottom plane of the roof insulation and the plane of the bottom of the roof deck.
- The wall insulation values in Tables 5.5-0 through 5.5-8 shall be adjusted in accordance with Table 5.5.5.1.1-1.
62 ANSI/ASHRAE/IES Standard 90.1-2022 (I-P)
insulation both sides of parapet with exterior wall insulation.