Fire performance of steel and plasterboard sheathed non-load bearing LSF walls

Light gauge steel-framed (LSF) walls are used as load bearing and non-load bearing building components in traditional concrete framed buildings and emerging all-steel structures. Recent building fire disasters around the world have highlighted the necessity for improved fire performance in such building components. While the fire performance of gypsum plasterboard, magnesium oxide board, calcium silicate board and oriented strand board (OSB) sheathed LSF walls has been assessed using fire tests and numerical analyses in the past, fire performance of steel sheathed walls remains unknown. Steel sheathing can improve the in-plane shear capacity of steel framed walls and is an accepted lateral load carrying system with widespread applications in the cold-formed steel construction industry. This paper presents the results of a series of small-scale fire tests conducted on steel and gypsum plasterboard sheathed composite panels and framed walls, and also an enthalpy based analytical study using the experimental results. Provision of steel sheathing either only internally, only externally or both internally and externally in combination was found to enhance the fire performance of plasterboard panels and plasterboard framed walls. The confinement of water within plasterboards for a prolonged duration with the provision of steel sheathing was found to be the prime cause of this improvement. Furthermore, the formation of thermal bridges across the stud in cavity insulated walls was found to reduce the fire performance significantly.