Enhanced thermal resistance of CFS acoustic stud walls: Numerical investigation and improved calculation guidelines

This study focuses on the thermal resistances (R-values) of advanced cold-formed steel (CFS) stud walls made of acoustic studs, with the aim of improving their calculation equations. In the first stage, detailed 2D finite element (FE) models were developed and subsequently validated against results of hot box tests from the literature, forming the basis for a parametric study. It revealed that the R-values of CFS stud walls made of acoustic studs were considerably (up to 30%) greater than those of conventional walls made of unstiffened channel studs, highlighting the high efficiency of the advanced design solution. Furthermore, the influences of wall components on their R-values were assessed, providing a deeper understanding of the thermal performance of the investigated wall configurations. All FE analysis results indicated that the R-value estimation equations in the current standard in New Zealand (NZS 4214) are generally unsuitable for the investigated walls. Therefore, in the final stage of the study, new calculation guidelines with improved equations were proposed, offering accurate predictions for practical application. The findings support the use of acoustic studs as an effective strategy for mitigating thermal bridging and improving the energy efficiency of CFS wall systems.