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Abstract
This paper presents a progress report on field thermal performance measurements on a set of private industry produced, experimental polyisocyanurate laminate board stock forms blown with CFC-11, HCFC-123, HCFC-14lb, 50/50, and 65/35 blends of HCFC-123/HCFC-14lb. These boards have been observed for almost 300 days of roof field exposure in East Tennessee at the Oak Ridge National Laboratory. The field data are used to derive an empirical model which can be used to predict effective diffusion coefficients for the air components into the foam cells. These diffusion coefficients are compared with those developed from steady state lab measurements of thin sliced samples from the same batch of experimental boards. The relative performance of test specimens of HCFC-14lb under a black and under a white membrane are reported. The aging of the HCFC-14lb blown foam under the white membrane occurred more slowly during cold weather, but accelerated after the winter season, resulting in no significant resistivity difference after 280 days of exposure from Sept. 1989 to May 1990. The field data analysis suggests that the percent increase in k over the foam blown with CFC-11 is, after one year of aging, 5.5% for HCFC-123 and 11.7% for HCFC-14lb. This leads to the same ordering as derived from this lab thin-slicing analysis report in Part 3 of this session. Additional plans are described for futher thermal and mechanical property measurements to be conducted on a second ORNL roof field tester. After the first year of this three-year study, there has been no indication that thermal performance differnces are serious enough to suggest that any of the HCFC alternative blowing agents would not be technically viable in polyisocyanurate roof insulation.
This paper presents a progress report on field thermal performance measurements on a set of private industry produced, experimental polyisocyanurate laminate board stock forms blown with CFC-11, HCFC-123, HCFC-14lb, 50/50, and 65/35 blends of HCFC-123/HCFC-14lb. These boards have been observed for almost 300 days of roof field exposure in East Tennessee at the Oak Ridge National Laboratory. The field data are used to derive an empirical model which can be used to predict effective diffusion coefficients for the air components into the foam cells. These diffusion coefficients are compared with those developed from steady state lab measurements of thin sliced samples from the same batch of experimental boards. The relative performance of test specimens of HCFC-14lb under a black and under a white membrane are reported. The aging of the HCFC-14lb blown foam under the white membrane occurred more slowly during cold weather, but accelerated after the winter season, resulting in no significant resistivity difference after 280 days of exposure from Sept. 1989 to May 1990. The field data analysis suggests that the percent increase in k over the foam blown with CFC-11 is, after one year of aging, 5.5% for HCFC-123 and 11.7% for HCFC-14lb. This leads to the same ordering as derived from this lab thin-slicing analysis report in Part 3 of this session. Additional plans are described for futher thermal and mechanical property measurements to be conducted on a second ORNL roof field tester. After the first year of this three-year study, there has been no indication that thermal performance differnces are serious enough to suggest that any of the HCFC alternative blowing agents would not be technically viable in polyisocyanurate roof insulation.
Date
10/1990
10/1990
Author(s)
J Christian; G Courville; R Linkous; R Wendt; T Smith; R Graves
J Christian; G Courville; R Linkous; R Wendt; T Smith; R Graves
Page(s)
247-259
247-259
Keyword(s)
CFC-11; HCFC-123; HCFC-14lb; thermal aging; polyisocyanurate; roof insulation; blowing agent
CFC-11; HCFC-123; HCFC-14lb; thermal aging; polyisocyanurate; roof insulation; blowing agent