Hot-box measurements to investigate the internal convection of highly insulated loose-fill insulation roof structures
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Yksityiskohdat
| Alkuperäiskieli | Englanti |
|---|---|
| Artikkeli | 109934 |
| Julkaisu | Energy and Buildings |
| Vuosikerta | 216 |
| DOI - pysyväislinkit | |
| Tila | Julkaistu - 1 kesäkuuta 2020 |
| OKM-julkaisutyyppi | A1 Alkuperäisartikkeli |
Tiivistelmä
The purpose of this study was to investigate how internal convection in loose-fill insulations affects the insulation properties of highly insulated roof structures. This study consists of laboratory measurements of roof structures insulated by two different blown-in insulations. The measurements are repeated with two temperature differences and air velocities for 300 mm and 600 mm thick insulation layers both with and without trusses, making a total of 24 case studies. The measurements were conducted with equipment using the calibrated hot-box method. The results of the tests show that internal convection can reduce insulation capacity significantly, especially with low-density loose-fill insulations, such as blown-in glass wool. A critical evaluation should be performed as to whether international standards and national building regulations take internal convection into account adequately. According to this study, 5 should be used as a critical modified Rayleigh number for horizontal roof structures with an open upper surface when used insulation material is loose-fill glass wool or wood fibre insulation as in this study.