Moisture and Heat Flow in Concrete Walls Exposed to Fire
Publication: Journal of Engineering Mechanics
Volume 120, Issue 10
Abstract
Time‐dependent distributions for temperature and moisture content in a concrete wall subjected to fire are determined by a model of heat and mass transfer in porous media. Free‐water flow, bound‐water diffusion, gas‐phase flow, water‐vapor diffusion, and thermal energy are accounted for in the model. The governing transient differential equations are discretized by a control‐volume formulation reported by Patankar in 1980, and solved in time using a fully implicit scheme. Two different fire exposure curves (namely, standard curve according to ASTM E‐119 and a more realistic curve reported by Ellingwood in 1991) are employed in the analysis. The assessment of two simplified models, in which all pore water is assumed to evaporate at 100°C, is performed by comparing their predictions to the full analysis. For temperature and saturation, the time developments predicted by the two simplified models and by the full analysis present similar trends; however, the simplified models seem to be appropriate only for very preliminary fire safety analyses, since they tend to underestimate temperatures.
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Information & Authors
Information
Published In
Journal of Engineering Mechanics
Volume 120 • Issue 10 • October 1994
Pages: 2028 - 2043
Copyright
Copyright © 1994 American Society of Civil Engineers.
History
Received: Apr 30, 1993
Published online: Oct 1, 1994
Published in print: Oct 1994
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