Load-bearing fire rating is essential for maintaining the structural integrity of light steel frame (LSF) walls during fire events. While most studies examine single-sided fire exposure, two-sided exposure, relevant in some internal wall scenarios, remains underexplored. This study investigates the impact of both side fire exposure on the load-bearing fire rating of LSF walls under various fire conditions.
This research employs finite element modelling (FEM) to simulate the structural and thermal response of LSF walls under two-sided fire exposure. The models were calibrated and validated using experimental data from previous studies to ensure accuracy. Parametric studies were conducted to evaluate the effects of plasterboard thickness, number of layers, cavity insulation and load ratios under varying fire scenarios including standard, prolonged, rapid and hydrocarbon fires.
The results reveal that two-sided fire exposure significantly reduces the load-bearing fire rating of LSF walls compared to single-sided exposure. Under rapid and hydrocarbon fire conditions, the fire rating was reduced by up to 72%. Conversely, standard and prolonged fires resulted in lower reductions. The degradation in performance varies with construction configuration and exposure type, indicating that certain wall assemblies are more vulnerable under both side fire exposure.
This study provides the first comprehensive computational investigation into LSF wall performance under two-sided fire conditions. The findings highlight critical gaps in current design practices, emphasizing the need for revised fire safety assessments for internal walls potentially exposed to both side fire scenarios. Designers and engineers can use these insights to improve fire resistance strategies in buildings using LSF systems.
