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Whole wall rating/label for structural insulated panel: steady-state thermal analysis

Kosny, J., Desjarlais, A. and , J.Christian
1999
Oak Ridge National Laboratory, Buildings Technology Center

Kosny, J., Desjarlais, A. and , J.Christian, (1999), "Whole wall rating/label for structural insulated panel: steady-state thermal analysis", Oak Ridge National Laboratory, Buildings Technology Center.
Abstract:
The objective of the whole wall rating project at Oak Ridge National Laboratory (ORNL) is to demonstrate the impact of real-world construction techniques on the reported R-value of construction systems. Previous testing on 2 x 4 and 2 x 6 wood frame walls insulated using fiberglass batts indicates that although the clear walls (that portion of the wall that is between the framing members) are R-10.55 (2 x 4 at 16 in. o.c.), R-10.83 (2 x 4 at 24 in. o.c.), and R-16.36 (2 x 6 at 24 in. o.c.) the wall details and other framing play a significant role in determining overall thermal performance. Whole wall R-values are substantially reduced by framing members and construction details in these assemblies. Guarded hot-box testing reveals that actual R-values are R-9.58. R-9.81, and R-13.69, respectively. For the tested 3.5-in. core structural insulated panel (SIP) wall, the clear wall R-value is R-15.17 and the whole wall R-value is as high as R-14.09. The whole wall R-value comparison between the SIP wall with added exterior wood siding and 0.5-in. interior gypsum board and typical 2 x 4 and 2 x 6 wood frame walls with added wood siding and 0.5-in. gypsum board shows that the SIP wall outperforms the 2 x 4 wood frame walls by more than R-4 and 2 x 6 wood frame walls by R-0.2 to R-0.4.

The analyses performed at ORNL show that for most wall systems, construction details reduce R-values stated for clear wall configurations. However, test results and three-dimensional finite difference computer modeling prove that such reductions in SIP wall constructions are small. This indicates that the SIP wall system is designed and engineered to be thermally efficient.

Whole Wall Rating lab-SIP-steady-state.pdf
Author Information and Other Publications Notes
Kosny, J.
  1. Effect of framing factor on clear wall r-value for wood and steel framed walls
  2. Multi-dimensional heat transfer through complex building envelope assemblies in hourly energy simulation programs
  3. The whole wall thermal performance calculator-on the net
  4. Theoretical and experimental thermal performance analysis of complex thermal storage membrane containing bio-based phase-change  
Desjarlais, A.
Program Manager, Building Materials and Structures, Oak Ridge National Laboratory, Bethel Valley Rd., Bldg 3147, Oak Ridge, TN 37831-6070, e-mail: yt7@ornl.gov
  1. An educational hygrothermal model: WUFI-ORNL/IBP
  2. Investigation of common thermal bridges in walls
  3. Laboratory measurements of the drying rates of low-slope roofing systems
  4. Moisture control in low-slope roofing: a new design requirement
  5. Moisture studies of a self-drying roof: tests in the large-scale climate simulator and results from thermal and hygric models
  6. Moisture: its effects on the thermal performance of a low-slope roof system
  7. Self-drying roofs: What? No dripping!
  8. The whole wall thermal performance calculator-on the net
  9. Water-vapor measurements of low-slope roofing materials  
Christian, J.
Oak Ridge National Laboratory
  1. Laboratory measurements of the drying rates of low-slope roofing systems
  2. Moisture control in low-slope roofing: a new design requirement
  3. Moisture: its effects on the thermal performance of a low-slope roof system
  4. The whole wall thermal performance calculator-on the net  


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