ASHRAE-90.1-2022- - Page 236
Extracted Content
Table A2.5.2 Assembly U-Factors for Attic Roofs with Steel Joists (4.0 ft on Center)
| Rated R-Value of Insulation Alone | Overall U-Factor for Entire Assembly |
|---|---|
| R-0 | U-1.282 |
| R-4 | U-0.215 |
| R-5 | U-0.179 |
| R-8 | U-0.120 |
| R-10 | U-0.100 |
| R-11 | U-0.093 |
| R-12 | U-0.086 |
| R-13 | U-0.080 |
| R-15 | U-0.072 |
| R-16 | U-0.068 |
| R-19 | U-0.058 |
| R-20 | U-0.056 |
| R-21 | U-0.054 |
| R-24 | U-0.049 |
| R-25 | U-0.048 |
| R-30 | U-0.041 |
| R-35 | U-0.037 |
| R-38 | U-0.035 |
| R-40 | U-0.033 |
| R-45 | U-0.031 |
| R-50 | U-0.028 |
| R-55 | U-0.027 |
234 ANSI/ASHRAE/IES Standard 90.1-2022 (I-P)