Thermal resistance of attic loose-fill insulations decreases under simulated winter conditions

Graves, R S; Wilkes, K E; McElroy, D L

doi:10.2172/10155056

Title: Thermal resistance of attic loose-fill insulations decreases under simulated winter conditions

Full Record
Other Related Research

Abstract

Two absolute techniques were used to measure the thermal resistance of attic loose-fill insulations: the Large Scale Climate Simulator (LSCS) and the Unguarded Thin-Heater Apparatus (UTHA). Two types of attic loose-fill insulations (unbonded and bonded/cubed) were tested under simulated winter conditions. To simulate winter conditions for an attic insulation, the specimens were tested with heat flow up, large temperature differences, and an air gap. The specimens were tested either with a constant mean temperature (30 or 21{degrees}C) and an increasing temperature difference or with a constant base temperature (21{degrees}C) and an increasing temperature difference (i.e., a decreasing mean temperature). The UTHA test specimens had a nominal thickness of 0.2 m of loose-fill insulation. The LSCS test specimens had a nominal thickness of 0.3 m of loose-fill insulation contained in a 4.2 by 5 m attic test module with a gypsum board base. The module had a gabled attic with a 5 in 12 slope roof. The tests yielded the surface-to-surface thermal resistance, R, which includes the thermal resistance due to gypsum, insulation, and any wood joists. Tests with and without an air gap were conducted in the UTHA. Surface-to-surface thermal resistance results from the LSCS and the UTHA show similarmore »« less

Authors:: Graves, R S; Wilkes, K E; McElroy, D L

Publication Date:: Sun May 01 00:00:00 EDT 1994

Research Org.:: Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

Sponsoring Org.:: USDOE, Washington, DC (United States)

OSTI Identifier:: 10155056

Report Number(s):: ORNL/M-3253
ON: DE94012502; TRN: 94:005744

DOE Contract Number:: AC05-84OR21400

Resource Type:: Technical Report

Resource Relation:: Other Information: PBD: May 1994

Country of Publication:: United States

Language:: English

Subject:: 32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION; THERMAL INSULATION; R FACTORS; THERMAL ANALYSIS; EXPERIMENTAL DATA; ATTICS; HEAT TRANSFER; MEASURING METHODS; 320107; BUILDING SYSTEMS

Citation Formats


                    Graves, R S, Wilkes, K E, and McElroy, D L. Thermal resistance of attic loose-fill insulations decreases under simulated winter conditions.  United States: N. p., 1994. 
        Web.  doi:10.2172/10155056.

Copy to clipboard


                    Graves, R S, Wilkes, K E, & McElroy, D L. Thermal resistance of attic loose-fill insulations decreases under simulated winter conditions.  United States.  https://doi.org/10.2172/10155056

Copy to clipboard


                    Graves, R S, Wilkes, K E, and McElroy, D L. 1994.  
        "Thermal resistance of attic loose-fill insulations decreases under simulated winter conditions".  United States.  https://doi.org/10.2172/10155056.  https://www.osti.gov/servlets/purl/10155056.

Copy to clipboard


                    
@article{osti_10155056,

  title        = {Thermal resistance of attic loose-fill insulations decreases under simulated winter conditions},

  author       = {Graves, R S and Wilkes, K E and McElroy, D L},

  abstractNote = {Two absolute techniques were used to measure the thermal resistance of attic loose-fill insulations: the Large Scale Climate Simulator (LSCS) and the Unguarded Thin-Heater Apparatus (UTHA). Two types of attic loose-fill insulations (unbonded and bonded/cubed) were tested under simulated winter conditions. To simulate winter conditions for an attic insulation, the specimens were tested with heat flow up, large temperature differences, and an air gap. The specimens were tested either with a constant mean temperature (30 or 21{degrees}C) and an increasing temperature difference or with a constant base temperature (21{degrees}C) and an increasing temperature difference (i.e., a decreasing mean temperature). The UTHA test specimens had a nominal thickness of 0.2 m of loose-fill insulation. The LSCS test specimens had a nominal thickness of 0.3 m of loose-fill insulation contained in a 4.2 by 5 m attic test module with a gypsum board base. The module had a gabled attic with a 5 in 12 slope roof. The tests yielded the surface-to-surface thermal resistance, R, which includes the thermal resistance due to gypsum, insulation, and any wood joists. Tests with and without an air gap were conducted in the UTHA. Surface-to-surface thermal resistance results from the LSCS and the UTHA show similar trends for these two types of loose-fill insulation when tested under simulated winter conditions. Tests with no air gap gave values of R that agreed with the bag label R-value for the insulations; R increased with lower mean temperatures. These no-gap values of R were 2 to 5% greater than the values of R obtained with an air gap for temperature differences of less than 22{degrees}C. For larger temperature differences R decreased, and at temperature differences of over 40{degrees}C, the R values were 50% less than those at small temperature differences.},

  doi          = {10.2172/10155056},

  url          = {https://www.osti.gov/biblio/10155056},
  journal      = {},
number       = ,

  volume       = ,

  place        = {United States},

  year         = {Sun May 01 00:00:00 EDT 1994},

  month        = {Sun May 01 00:00:00 EDT 1994}

}

Copy to clipboard

Technical Report:

View Technical Report (2.31 MB)

https://doi.org/10.2172/10155056

Save / Share:

Export Metadata

Save to My Library

Similar records in OSTI.GOV collections:

Attic testing at the Roof Research Center: Initial results

Conference Wilkes, K; Wendt, R; Delmas, A; ...

In 1990, a series of tests was performed on residential attics using an attic test module built to permit research to be accomplished on a number of issues related to attics. This test module was used in the Large Scale Climate Simulator (LSCS) at the Roof Research Center. This combination of test module and LSCS permitted the Center to perform a number of studies under closely controlled interior and climatic conditions including: evaluation of uninsulated attic performance and comparison with previously published results, evaluation of the thermal performance of the attic with loose-fill fiberglass insulation, and the identification of heatmore »« less
The thermohysical properties of gypsum boards containing wax

Conference Graves, R; McElroy, D; Yarbrough, D; ...

An Unguarded Thin-Heater Apparatus (UTHA) was used to measure the thermal conductivity (k) and thermal diffusivity ({alpha}) of gypsum boards containing 0, 15, 30 wt % wax (C{sub 18}H{sub 38}) in the temperature range 20 to 50{degree}C (68 to 122{degree}F). Since this wax melts near 28{degree}C (82{degree}F), this combination provides a phase-change material for possible use in building applications. The k-values for gypsum board without wax reported here are independent of temperature and extend the available data to a lower density ({rho}). The k-values agree with data by Malloy but are 17% greater than the ASHRAE Handbook value. The k-valuesmore »« less
Full Text Available
Steady-state and transient tests using the unguarded thin-heater apparatus (thermophysical properties of building materials)

Technical Report McElroy, D; Graves, R; Yarbrough, D; ...

The Oak Ridge National Laboratory unguarded thin-heater apparatus (UTHA) was used to determine the thermophysical properties of building materials from 24 to 50{degrees}C (75 to 120{degrees}F). Steady-state and transient modes of operation yielded data on four types of material: (1) gypsum wallboard containing 0, 15, and 30 wt % wax; (2) calcium silicate insulations with densities of 307, 444, and 605 kg/m{sup 3}; (3) three wood products; and (4) two cellular plastic foams. The extruded polystyrene was measured 25, 45, 74, 131, and 227 d after production. In the steady-state mode of operation, the UTHA yields the thermal conductivity specimen.more »« less
Thermal performance of fiberglass and cellulose attic insulations

Conference Wilkes, K; Childs, P

A series of experiments has been completed on the thermal performance of fiberglass and cellulose attic insulations under winter conditions using an attic test module in a guarded hot box facility. Experiments with one type of loose-fill fiberglass insulation showed that the thermal resistance at large temperature differences (70 to 76{degrees}F) was about 35 to 50% less than at small temperature differences. The additional heat flow, attributed to natural convection, was effectively eliminated by applying a covering of fiberglass batts or a combination of a polyethylene film and fiberglass blankets. No significant convection was found either with fiberglass batts ormore »« less
Thermal performance of fiberglass and cellulose attic insulations

Conference Wilkes, K; Childs, P

A series of experiments has been completed on the thermal performance of fiberglass and cellulose attic insulations under winter conditions using an attic test module in a guarded hot box facility. Experiments with one type of loose-fill fiberglass insulation showed that the thermal resistance at large temperature differences (70 to 76{degrees}F) was about 35 to 50% less than at small temperature differences. The additional heat flow, attributed to natural convection, was effectively eliminated by applying a covering of fiberglass batts or a combination of a polyethylene film and fiberglass blankets. No significant convection was found either with fiberglass batts ormore »« less
Full Text Available

Similar Records