Assessment of Energy Rating of Polyurethane Spray Foam Walls: Procedure and Interim Results
Bibliographic record
Abstract
The application of polyurethane spray foam (SPF) insulation in buildings provides a durable and efficient thermal barrier. The industry is also promoting the SPF as an effective air barrier system in addition to its thermal insulation characteristics. In an effort to address these issues, a consortium of SPF manufacturers and contractors, jointly with the National Research Council of Canada's Institute for Research in Construction conducted an extensive research project to assess the thermal and air leakage characteristics of SPF walls as well as conventional wall assemblies. The objective is to develop analytical and experimental procedures to determine a wall energy rating (WER) that captures both the thermal and airleakage performance of a wall assembly. The experimental part included two streams of testing: (1) To determine the wall air leakage rate at different conditions and (2) their thermal resistance, R-value, at different temperature differences. An analytical procedure was also developed to calculate WER by combining the heat loss due to thermal transmission and that due to air leakage with the aim of arriving at WER. Six conventional full-scale wood frame wall assemblies were built, two with glass fiber batts and of four with medium density SPF. Some walls were constructed without penetrations and others were built with penetrations. The testing regime included: (i) Initial testing of air leakage and thermal resistance; (ii) conditioning in the dynamic wall test facility according to an established routine; and (iii) retesting for air leakage and thermal resistance. This paper presents the results of six walls included in this project. The focus of this paper will be on presenting a brief summary of the project objective, testing protocol, and the theoretical approach to determine the WER number for the six walls.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.003 | 0.004 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.001 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".