Joint Industry/Government Research Project: Comparison of thermal aging for roof exposures and thin-specimens of experimental polyisocyanurate insulation foamed with alternative blowing agents

Conference · Tue Jan 01 00:00:00 EST 1991

OSTI ID:5745257

Graves, R S; Christian, J E; McElroy, D L

This paper reports apparent thermal conductivity (k) values from field exposures and laboratory aging of a set of industry-produced, experimental polyisocyanurate (PIR) laminated boardstock foamed with hydrochlorofluorocarbons (HCFCs) as alternative to chlorofluorocarbons (CFCs). The k-values were determined from 0 to 50{degree}C using techniques that meet ASTM C 1114 (Thin Heater Apparatus) and ASTM C 518 (Heat Flow Meter Apparatus). The increase in k observed for field exposure in the ORNL Roof Thermal Research Apparatus (RTRA) was confirmed by independent laboratory tests. The observed laboratory increase in k was about the same, between 17 and 22%, for all three blowing agent foams for a 450 day field exposure in the RTRA. Thin specimens were planed from the industry-produced boardstock foams and aged at 24 and 65{degree}C for up to 460 days. The foams blown with alternative blowing agents exhibited long-term k-values 7 to 15% above those for CFC foams under similar conditions. Field exposures were conducted on specimens under single ply EPDM membranes in the RTRA for over 680 days. Hourly averages of panel temperature and heat flux were analyzed to obtain k as a function of mean insulation temperature on a week-by-week basis. The k-values derived from the field data provided effective diffusion coefficients for air in the foam, which were within 7% of those obtained from the thin-specimen aging procedure at 24%C except for one sample. The relative performance of test specimens of HCFC-141b under a black and under a white membrane is reported, and data suggest that differences are relatively small. 26 refs., 10 figs., 8 tabs.

• Research Organization: Oak Ridge National Lab., TN (USA)
• Sponsoring Organization: USDOE; USEPA; USDOE, Washington, DC (USA); Environmental Protection Agency, Washington, DC (USA)
• DOE Contract Number: AC05-84OR21400
• OSTI ID: 5745257
• Report Number(s): CONF-9109158-1; ON: DE91012963
• Resource Relation: Conference: 1991 polyurethanes world congress, Nice (France), 24-26 Sep 1991
• Country of Publication: United States
• Language: English

Related Subjects

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION
BUILDING MATERIALS
THERMAL CONDUCTIVITY
THERMAL INSULATION
AGING
FOAMS
HALOGENATED ALIPHATIC HYDROCARBONS
HEAT FLOW
ROOFS
TEMPERATURE EFFECTS
COLLOIDS
DISPERSIONS
MATERIALS
ORGANIC COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
PHYSICAL PROPERTIES
THERMODYNAMIC PROPERTIES
320107* - Energy Conservation
Consumption
& Utilization- Building Systems- (1987-)