Thickness and Density Measurements for Attic Loose-Fill Thermal Insulations in Eight Cities

摘要

Thickness and density data for loose-fill thermal insulation installed in residential attics have been obtained in eight cities during the period 1979 through 1986. The field data provide a basis for estimating the amount of insulation settling that occurs after installation. The field study has progressed through stages of increasing complexity to include: (1) density measurements 1 to 10 years after installation; (2) monitoring of insulation density and thickness with time, starting with installation; and (3) monitoring of insulation density and thickness with time, starting with installation at densities near the manufacturer's recommended value. The first part of the study revealed unexpectedly high insulation densities. The latter parts of the study have shown that settling continues for about 2 years after installation. Sufficient data were collected to construct correlations that can be used to predict final thickness or density values for the products that were tested. The mineral fiber insulations installed near label density showed thickness loss in the range of 6 to 7% while products installed at densities 20% or more above the manufacturer's recommended value did not settle. Data obtained for loose-fill cellulosic insulation shows settling for at least 2 years that can be correlated with results from the blower-cyclone-shaker test for settled density. This report includes an analysis of the effect of settling on R-value and correlations that are useful for calculating R-values from thickness and density measurements. (ERA citation 13:014876)