Section N1102 (R402) Building Thermal Envelope
TABLE N1102.1.2 (R402.1.2)
INSULATION AND FENESTRATION REQUIREMENTS BY COMPONENTa
|3||0.32||0.55||0.25||38||20 or 13 + 5h||8/13||19||5/13f||0||5/13|
|4 except |
|0.32||0.55||0.40||49||20 or 13 + 5h||8/13||19||10/13||10, 2 ft||10/13|
|0.30||0.55||NR||49||20 or 13 + 5h||13/17||30g||15/19||10, 2 ft||15/19|
|6||0.30||0.55||NR||49||20 + 5h or 13 + 10h||15/20||30g||15/19||10, 4 ft||15/19|
|7 and 8||0.30||0.55||NR||49||20 + 5h or 13 + 10h||19/21||38g||15/19||10, 4 ft||15/19|
For SI: 1 foot = 304.8 mm.
NR = Not Required.
- R-values are minimums. U-factors and SHGC are maximums. Where insulation is installed in a cavity that is less than the label or design thickness of the insulation, the installed R-value of the insulation shall be not less than the R-value specified in the table.
- "10/13" means R-10 continuous insulation on the interior or exterior of the home or R-13 cavity insulation on the interior of the basement wall. "15/19" means R-15 continuous insulation on the interior or exterior of the home or R-19 cavity insulation on the interior of the basement wall. Alternatively, compliance with "15/19" shall be R-13 cavity insulation on the interior of the basement wall plus R-5 continuous insulation on the interior or exterior of the home.
- R-5 insulation shall be provided under the full slab area of a heated slab in addition to the required slab edge insulation R-value for slabs. as indicated in the table. The slab edge insulation for heated slabs shall not be required to extend below the slab.
- There are no SHGC requirements in the Marine Zone.
- Basement wall insulation shall not be required in warm-humid locations as defined by Figure N1101.7 and Table N1101.7.
- Alternatively, insulation sufficient to fill the framing cavity providing not less than an R-value of R-19.
- The first value is cavity insulation, the second value is continuous insulation. Therefore, as an example, "13+5" means R-13 cavity insulation plus R-5 continuous insulation.
- Mass walls shall be in accordance with Section N1102.2.5. The second R-value applies where more than half of the insulation is on the interior of the mass wall.
TABLE N1102.1.4 (R402.1.4)
|MASS WALL |
|4 except Marine||0.32||0.55||0.026||0.060||0.098||0.047||0.059||0.065|
|5 and Marine 4||0.30||0.55||0.026||0.060||0.082||0.033||0.050||0.055|
|7 and 8||0.30||0.55||0.026||0.045||0.057||0.028||0.050||0.055|
- Nonfenestration U-factors shall be obtained from measurement, calculation or an approved source.
- Mass walls shall be in accordance with Section N1102.2.5. Where more than half the insulation is on the interior, the mass wall U-factors shall not exceed 0.17 in Climate Zone 1, 0.14 in Climate Zone 2, 0.12 in Climate Zone 3, 0.087 in Climate Zone 4 except Marine, 0.065 in Climate Zone 5 and Marine 4, and 0.057 in Climate Zones 6 through 8.
- In warm-humid locations as defined by Figure N1101.7 and Table N1101.7, the basement wall U-factor shall not exceed 0.360.
Access doors from conditioned spaces to unconditioned spaces such as attics and crawl spaces shall be weatherstripped and insulated to a level equivalent to the insulation on the surrounding surfaces. Access that prevents damaging or compressing the insulation shall be provided to all equipment. Where loose-fill insulation is installed, a wood-framed or equivalent baffle or retainer shall be installed to prevent the loose-fill insulation from spilling into the living space when the attic access is opened. The baffle or retainer shall provide a permanent means of maintaining the installed R-value of the loose-fill insulation.
Exception: Vertical doors providing access from conditioned spaces to unconditioned spaces that comply with the fenestration requirements of Table N1102.1.2 based on the applicable climate zone specified in Section N1101.7.
Steel-frame ceilings, walls, and floors shall comply with the insulation requirements of Table N1102.2.6 or the U-factor requirements of Table N1102.1.4. The calculation of the U-factor for a steel-frame envelope assembly shall use a series-parallel path calculation method.
TABLE N1102.2.6 (R402.2.6)
STEEL-FRAME CEILING, WALL AND FLOOR INSULATION R-VALUES
|WOOD FRAME |
|Steel Truss Ceilingsb|
|R-30||R-38 or R-30 + 3 or R-26 + 5|
|R-38||R-49 or R-38 + 3|
|R-49||R-38 + 5|
|Steel Joist Ceilingsb|
|R-30||R-38 in 2 × 4 or 2 × 6 or 2 × 8 R-49|
in any framing
|R-38||R-49 in 2 × 4 or 2 × 6 or 2 × 8 or 2 × 10|
|Steel-Framed Wall, 16 inches on center|
|R-13||R-13 + 4.2 or R-21 + 2.8 or|
R-0 + 9.3 or R-15 + 3.8 or R-21 + 3.1
|R-13 + 3||R-0 + 11.2 or R-13 + 6.1 or R-15 + 5.7 or|
R-19 + 5.0 or R-21 + 4.7
|R-20||R-0 + 14.0 or R-13 + 8.9 or R-15 + 8.5 or|
R-19 + 7.8 or R-19 + 6.2 or R-21 + 7.5
|R-20 + 5||R-13 + 12.7 or R-15 + 12.3 or R-19 + 11.6 or|
R-21 + 11.3 or R-25 + 10.9
|R-21||R-0 + 14.6 or R-13 + 9.5 or R-15 + 9.1 or|
R-19 + 8.4 or R-21 + 8.1 or R-25 + 7.7
|Steel-Framed Wall, 24 inches on center|
|R-13||R-0 + 9.3 or R-13 + 3.0 or R-15 + 2.4|
|R-13 + 3||R-0 + 11.2 or R-13 + 4.9 or R-15 + 4.3 or|
R-19 + 3.5 or R-21 + 3.1
|R-20||R-0 + 14.0 or R-13 + 7.7 or R-15 + 7.1 or|
R-19 + 6.3 or R-21 + 5.9
|R-20 + 5||R-13 + 11.5 or R-15 + 10.9 or R-19 + 10.1 or|
R-21 + 9.7 or R-25 + 9.1
|R-21||R-0 + 14.6 or R-13 + 8.3 or R-15 + 7.7 or|
R-19 + 6.9 or R-21 + 6.5 or R-25 + 5.9
|Steel Joist Floor|
|R-13||R-19 in 2 × 6, or R-19 + 6 in 2 × 8 or 2 × 10|
|R-19||R-19 + 6 in 2 × 6, or R-19 + 12 in 2 × 8 or 2 × 10|
Floor framing-cavity insulation shall be installed to maintain permanent contact with the underside of the subfloor decking.
Exception: As an alternative, the floor framing-cavity insulation shall be in contact with the topside of sheathing or continuous insulation installed on the bottom side of floor framing where combined with insulation that meets or exceeds the minimum wood frame wall R-value in Table N1102.1.2 and that extends from the bottom to the top of all perimeter floor framing members.