Light gauge Steel Frame (LSF) walls are commonly used in building construction. In general, they are lined with single or double layers of gypsum plasterboards with and without cavity insulation. Gypsum plasterboards act as a thermal barrier to protect the thin-walled steel studs from rapid temperature rise. In these walls, plasterboard joints are located along the studs for ease of construction and are protected by filler materials. During fires, these plasterboard joints crack and open up, and thus allow the stud temperatures to rise rapidly and initiate premature structural failures in LSF walls. This research investigated the detrimental effects of these plasterboards joints on the fire resistance rating of single and double plasterboard lined walls based on the hot flange time-temperature profiles of studs from full scale fire tests. To overcome the detrimental effects of plasterboard joints, the back-blocking technique was used, where plasterboard joints were placed between studs with 150 mm wide plasterboards as back-blocks. Full scale fire tests and numerical studies were performed on single plasterboard lined load bearing LSF wall panels to investigate the improved fire performance by using this technique. They showed that the fire resistance rating of these LSF walls was increased by 25% in comparison to the conventional plasterboard joint arrangement over the studs. This paper presents the details of this research on the detrimental effects of plasterboard joints on the fire resistance of load bearing LSF walls, and the results. It also includes a discussion and results for non-load bearing LSF walls.
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