The Thermal Performance of Several Australian Fibrous Insulating Materials

Abstract

The thermal conductivity of fibrous insulation materials most com monly used in Australian buildings has been measured over a range of typical densi ties and thicknesses. Correlating equations for thermal conductivity as a function of density have been derived for each material. The materials studied have included batt or blanket form (low-density fibreglass, sheep's wool, and polyester fibre) and loose-fill form (cellulose fibre, two types of sheep's wool, and rockwool). Despite their widespread use, thermal properties data for some of these materials have not been widely available. This paper is concerned primarily with the effect of density on a material's thermal conductivity. However, sheep's wool has been found to be a highly variable material where knowledge of density, although important, is insufficient to allow performance prediction with confidence. Data which demonstrates this variability in performance over many in dividual samples of loose-fill sheep's wool is presented. For all test materials, charts are presented which relate thermal performance to thickness, density, and material quantity. These are intended as a guide to developers, manufacturers and installers in assessing the relative merits of alternative insulation types.