Influence of gypsum board type (X or C) on real fire performance of partition assemblies

This paper compares the responses of wall-size partition assemblies, composed of either type X or type C gypsum wallboard panels over steel studs, when each was exposed to an intense room fire. The exposures lasted from the time of ignition to beyond flashover. Heat flux gauges provided time histories of the energy incident on the partitions, while thermocouples provided data on the propagation of heat through the partitions and on the progress toward perforation. Visual and infrared cameras were used to image partition behaviour during the fire exposure. Contraction of the seams of the two types of assemblies occurred under similar thermal conditions on the unexposed surface. However, there were noticeable differences in cracking behaviour. Reduced scale experiments were performed in conjunction with the real-scale fire tests to provide insight into the contraction and cracking behaviour of the different gypsum board types. Results obtained from these experiments are discussed. Copyright (C) 2006 John Wiley & Sons, Ltd.