Full-Scale CFD Simulation of Gypsum Plasterboard Wall Assemblies Exposed to Fire: Effects of Gypsum Dehydration

Gypsum “dehydration” phenomena, occurring when gypsum plasterboard wall assemblies are exposed to a high temperature environment, result in water vapour production and subsequent dispersion in the fire compartment; however, these phenomena are commonly neglected in relevant Computational Fluid Dynamics (CFD) simulations. In order to investigate the impact of gypsum dehydration in full-scale CFD simulations of gypsum plasterboard wall assemblies, the FDS code is used to simulate a two-storey residential building, exposed to a typical domestic fire scenario. A structural steel frame is used in the investigated building, combined with gypsum plasterboard wall assemblies. The effects of gypsum dehydration are taken into account by using a dedicated solid reaction kinetics model; the obtained predictions are compared to a benchmark test case where no such phenomena are modelled. The performed simulations clearly indicate that the explicit simulation of gypsum dehydration
phenomena has a prominent effect on CFD predictions; the developed solid reaction kinetics model allows, for the first time, the CFD simulation of gypsum dehydration induced water vapour production and dispersion in the fire compartment.