Analytical Models for Settling of Attic Loose-Fill Thermal Insulation

Abstract

Settling of attic loose-fill thermal insulation is a long-term process. Settling depends on the quality of the loose-fill insulation and the attic conditions during the service life. The main factors affecting settling of attic loose-fill insulation are density (mass), climate of the attic, and vibrations of the building structure. Analytical models for settling of attic loose-fill thermal insulation can be helpful for both interpretation and prediction of observed settling behaviour. The prediction of the settling process of loose-fill thermal insulation in a model is valuable when estimating the thermal properties of the loose-fill insulation after a certain lifetime. Efforts to carry out a preliminary analytical model for the settling property have been made in two ways. Firstly, experimental field settling data have been used to fit a common logarithmic mathematical function. Secondly, a four-element linear vis coelastic model, the Burger model, has been adjusted to experimental field settling data. Comparison of the thirty years settling data calculated with the fitted logarithmic functions and the Burger equations has been performed for cellulose fibre and mineral fibre insulation (Svennerstedt, 1993).