Description |
|
U-factor (Btu/ºF-ft²) |
|
A | |
Uninsulated single-layer metal swinging doors or non-swinging doors, including single-layer uninsulated access hatches and uninsulated smoke vents: |
1 |
1.45 |
Uninsulated double-layer metal swinging doors or non-swinging doors, including double-layer uninsulated access hatches and uninsulated smoke vents: |
2 |
0.70 |
Insulated metal swinging doors, including fire-rated doors, insulated access hatches, and insulated smoke vents: |
3 |
0.50 |
Wood doors, minimum nominal thickness of 1-3/4 in. (44 mm), including panel doors with minimum panel thickness of 1-1/8 in. (28 mm), and solid core flush doors, and hollow core flush doors: |
4 |
0.50 |
Any other wood door: |
5 |
0.60 |
Uninsulated single layer metal roll up doors including fire rated door |
6 |
1.45 |
Insulated single layer metal sectional doors, minimum insulation nominal thickness of 1-3/8 inch; expanded polystyrene (R-4 per inch). |
7 |
0.179 |
Source: ASHRAE 90.1-2007, Section A7. |