Purpose
This research was aimed at investigating the fire performance of LSF wall systems by using 3-D heat transfer FE models of existing LSF wall system configurations.
Design/methodology/approach
This research was focused on investigating the fire performance of LSF wall systems by using 3-D heat transfer finite element models of existing LSF wall system configurations. The analysis results were validated by using the available fire test results of five different LSF wall configurations.
Findings
The validated finite element models were used to conduct a parametric study on a range of non-load bearing and load bearing LSF wall configurations to predict their fire resistance levels (FRLs) for varying load ratios.
Originality/value
Fire performance of LSF wall systems with different configurations can be understood by performing full-scale fire tests. However, these full-scale fire tests are time consuming, labour intensive and expensive. On the other hand, finite element analysis (FEA) provides a simple method of investigating the fire performance of LSF wall systems to understand their thermal-mechanical behaviour. Recent numerical research studies have focused on investigating the fire performances of LSF wall systems by using finite element (FE) models. Most of these FE models were developed based on 2-D FE platform capable of performing either heat transfer or structural analysis separately. Therefore, this paper presents the details of a 3-D FEA methodology to develop the capabilities to perform fully-coupled thermal-mechanical analyses of LSF walls exposed to fire in future.
Fire resistance of cold-formed light gauge steel frame (LSF) wall systems is enhanced by lining them with single or multiple layers of wall boards with varying thermal properties. These wall boards are gypsum plasterboards or Magnesium Oxide (MgO) boards produced by different manufacturers. Thermal properties of these boards appear to show considerable variations and this can lead to varying fire resistance levels (FRL) for their wall systems. Currently FRLs of wall systems are determined using full scale fire tests, but they are time consuming and expensive. Recent research studies on the fire performance of LSF wall systems have used finite element studies to overcome this problem, but they were developed based on 1-D and 2-D finite element platform capable of performing either heat transfer or structural analysis separately. Hence in this research a 3-D finite element model was developed first for LSF walls lined with gypsum plasterboard and cavity insulation materials. Accurate thermal properties of these boards are essential for finite element modelling, and thus they were measured at both ambient and elevated temperatures. This experimental study included specific heat, relative density and thermal conductivity of boards. The developed 3-D finite element model was then validated using the available fire tests results of LSF walls lined with gypsum plasterboard, and is being used to investigate the fire performance of different LSF wall configurations. The tested MgO board exhibited significant variations in their thermal properties in comparison to gypsum plasterboards with about 50% loss of its initial mass at about 500 ºC compared to 16% for gypsum plasterboards. Hence the FRL of MgO board lined LSF wall systems is likely to be significantly reduced. This paper presents the details of this research study on the fire performance of LSF wall systems lined with gypsum plasterboard and MgO board including the developed 3-D finite element models, thermal property tests and the results.
KEYWORDSThermal finite element model, Thermal properties, Gypsum plasterboard, MgO board, Fire performance.
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