SYMPOSIA PAPER Published: 01 January 1991

Moisture Diffusion in Thermal Insulating Materials


The moisture behaviour of building materials, especially the kinetics of wetting and drying, is very important because it can influence the hygrothermal performance of the building envelope and the internal comfort.

The mathematical model of heat and mass transfer, in porous media, proposed by LUIKOV — PHILIP and DE VRIES shows that moisture migration, in isothermal conditions, is a function of the humidity gradient and the moisture diffusivity coefficient. This paper reports values of moisture diffusivity coefficients for some thermal insulating materials and how these are calculated. The results of numerical simulation of drying of these materials and a comparison with the data obtained from measurements using gamma-ray spectroscopy in the determination of the moisture distribution are also presented.

Author Information

Freitas, V
Crausse, P
Abrantes, V
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Developed by Committee: C16
Pages: 389–400
DOI: 10.1520/STP16358S
ISBN-EB: 978-0-8031-5174-1
ISBN-13: 978-0-8031-1420-3