Vapor Convection in Gypsum Plasterboard Exposed to Fire: Numerical Simulation and Validation

Abstract

This article investigates the contribution of water vapor convection to heat transfer through gypsum plasterboard exposed to fire. The vapor is generated as a product of the endothermic dehydration reaction in gypsum, and it is then expelled from the material through the pore network by its own pressure, thereby taking part in the heat transfer from the fire-exposed to the cold surface of plasterboard. The gas permeability values of plasterboard core and paper liner are obtained experimentally. The results of simulations are validated against the temperature measurement data obtained for two types of commercial plasterboard tested in the standard fire ISO 834. It is shown that vapor convection plays an essential role in heat transfer through plasterboard during the initial stage of fire. The amount of condensate developing in the pores of the material is found to be low, which allows it to be neglected in engineering calculations.

The authors express their gratitude to K. Burkhard, W. Trindler, and R. Blessing for their help with permeability measurements, and to B. Weber for his critical analysis of the obtained permeability data. This study has been partly funded by the EU project I-SSB (Integrated Safe and Smart Built concept).

Notes

Each value is an average of six measurements. The experimental uncertainties specify the 95% confidence range, s σ, where s is the student factor and σ is the standard deviation (for six measurements, s = 2.6).