Picture of two heads

Open Access research that challenges the mind...

The Strathprints institutional repository is a digital archive of University of Strathclyde research outputs. Strathprints provides access to thousands of Open Access research papers by University of Strathclyde researchers, including those from the School of Psychological Sciences & Health - but also papers by researchers based within the Faculties of Science, Engineering, Humanities & Social Sciences, and from the Strathclyde Business School.

Discover more...

Temperature gradient effects on moisture transport in porous building materials

Baker, P.H. and Galbraith, G.H. and McLean, R.C. (2009) Temperature gradient effects on moisture transport in porous building materials. Building Services Engineering Research and Technology, 30 (1). pp. 37-48. ISSN 0143-6244

Full text not available in this repository. (Request a copy from the Strathclyde author)

Abstract

Whilst considerable research has been carried out on the process of moisture transmission through porous building materials under a concentration gradient with isothermal conditions, limited experimental data are available on the influence of temperature gradients on moisture transfer rates. Such thermodiffusion can be predicted from irreversible thermodynamics, however, its significance to concentration-driven transfer in materials has not been definitively established. Models for the prediction of moisture movement in building structures generally neglect such effects, and rely on moisture transport properties based on isothermal measurements. This paper describes an investigation to determine the significance of non-isothermal effects on the total moisture transfer through building materials. The investigation concluded that the vapour pressure gradient is the critical driving potential for moisture transfer, whilst thermodiffusion is not significant. Practical application: Building professionals can be confident that the use of vapour permeabilities of building materials measured under isothermal conditions are satisfactory for the prediction of moisture transport through building envelopes under temperature gradients: no correction for thermodiffusion effects is necessary.