In wall systems, airspaces can increase thermal resistance if a reflective material such as foil with low emissivity is installed in a furred-airspace assembly. In this article, the present model, hygIRC-C, was used to investigate the steady-state thermal resistance of wall assemblies that incorporate foil adhered to expanded polystyrene foam in a furred assembly. To investigate the effect of the furring orientation, the furring was installed horizontally and vertically and compared to walls with no furring. For wall with vertical furring, the three-dimensional version of the present model was used to capture the three-dimensional effect of the thermal bridges. Because the foil emissivity can be affected by dust accumulation and/or water vapor condensation on the foil surface, consideration was given to investigate the effect of both varying foil emissivity and outdoor temperature on the thermal performance of the various wall specimens. The results showed that the thermal resistance (R-value) of the reference wall (no furring) is greater than the wall specimens with furring. Also, the results showed that the contribution of the furred-airspace assembly to the R-value of wall specimen with vertical furring is higher than that for wall specimen with horizontal furring.
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American Society for Testing and Materials (ASTM) (2006) ASTM C-1363, standard test method for the thermal performance of building assemblies by means of a hot box apparatus. 2006 Annual Book of ASTM Standards 04.06. Philadelphia, PA: American Society for Testing and Materials, pp. 717–759. Available at: www.astm.org
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CravenCGarber-SlaghtR (2011) Product test: reflective insulation in cold climates. Technical report number TR 2011-01, 12April. Fairbanks, AK: Cold Climate Housing Research Center (CCHRC).
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ElmahdyAHMarefWSwintonMC. (2009) Development of energy ratings for insulated wall assemblies. In: 2009 building envelope symposium, NRCC-51419, San Diego, CA, 26October, pp. 21–30. Available at: http://www.nrc-cnrc.gc.ca/obj/irc/doc/pubs/nrcc51419.pdf.
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MarefWKumaranMKLacasseMA. (2002a) Laboratory measurements and benchmarking of an advanced hygrothermal model. In: Proceedings of the 12th international heat transfer conference, NRCC-43054, Grenoble, France, 18 August, pp. 117–122. Available at: http://www.nrc-cnrc.gc.ca/obj/irc/doc/pubs/nrcc43054/nrcc43054.pdf.
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MarefWLacasseMAKumaranMK. (2002b) Benchmarking of the advanced hygrothermal model-hygIRC with mid-scale experiments. In: eSim 2002 proceedings, NRCC-43970, University of Concordia, Montreal, Canada, 12 September, pp. 171–176. Available at: http://www.nrc-cnrc.gc.ca/obj/irc/doc/pubs/nrcc43970/nrcc43970.pdf.
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Reflective Insulation Manufacturers Association International (RIMA-I) (2002) Reflective Insulation, Radiant Barriers and Radiation Control Coatings. Olathe, KS: RIMA-I.
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SaberHH (2012) Investigation of thermal performance of reflective insulations for different applications. Building and Environment52: 32–44.
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SaberHHMarefW (2012) Effect of furring orientation on thermal response of wall systems with low emissivity material and furred-airspace. In: The building enclosure science & technology (BEST3) conference, Atlanta, GA, 2–4 April.
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SaberHHSwintonMC (2010) Determining through numerical modeling the effective thermal resistance of a foundation wall system with low emissivity material and furred—airspace. In: 2010 international conference on building envelope systems and technologies, ICBEST 2010, NRCC-53574, Vancouver, BC, Canada, 27–30 June, pp. 247–257. Available at: http://www.nrc-cnrc.gc.ca/obj/irc/doc/pubs/nrcc53574.pdf.
15.
SaberHHMarefWSwintonMC (2011a) Numerical investigation of thermal response of basement wall systems with low emissivity material and furred—airspace. In: 13th Canadian conference on building science and technology (13th CCBST) conference, Winnipeg, MB, Canada, 10–13 May.
16.
SaberHHMarefWSwintonMC (2011b) Thermal response of basement wall systems with low emissivity material and furred airspace. Journal of Building Physics. Epub ahead of print 5August2011. DOI: 10.1177/1744259111411652.
17.
SaberHHMarefWArmstrongM. (2010a) Benchmarking 3D thermal model against field measurement on the thermal response of an insulating concrete form (ICF) wall in cold climate. In: Building XI conference, Clearwater Beach, FL, 5–9 December.
18.
SaberHHMarefWElmahdyAH. (2010b) 3D thermal model for predicting the thermal resistances of spray polyurethane foam wall assemblies. In: Building XI conference, Clearwater Beach, FL, 5–9 December.
19.
SaberHHMarefWElmahdyH. (2012a) 3D heat and air transport model for predicting the thermal resistances of insulated wall assemblies. Journal of Building Performance Simulation5(2): 75–91.
20.
SaberHHMarefWLacasseMA. (2010c) Benchmarking of hygrothermal model against measurements of drying of full-scale wall assemblies. In: 2010 international conference on building envelope systems and technologies, ICBEST 2010, NRCC-53573, Vancouver, BC, Canada, 27–30 June, pp. 369–377. Available at: http://www.nrc-cnrc.gc.ca/obj/irc/doc/pubs/nrcc53573.pdf.
21.
SaberHHMarefWSherrerG. (2012b) Numerical modelling and experimental investigations of thermal performance of reflective insulations. Journal of Building Physics. Epub ahead of print 26April2012. DOI: 10.1177/1744259112444021.
22.
SaberHHMarefWSwintonMC. (2011c) Thermal analysis of above-grade wall assembly with low emissivity materials and furred-airspace. Building and Environment46(7): 1403–1414.
23.
SaberHHSwintonMCKalingerP. (2011d) Hygrothermal simulations of cool reflective and conventional roofs. In: 2011 NRCA international roofing symposium, emerging technologies and roof system performance, Washington, DC, 7–9 September.
24.
SaberHHSwintonMCKalingerP. (2012c) Long-term hygrothermal performance of White and Black roofs in North American climates. Building and Environment50: 141–154.
