QUANTIFICATION OF THERMAL BRIDGING EFFECTS IN COLD-FORMED STEEL WALL ASSEMBLIES

• Main Author: Kapoor, Divyansh
• Format: Others
• Published: ScholarWorks@UMass Amherst 2020
• Subjects: Cold Formed Steel; Thermal Bridging; Thermal Transmittance; 3-D Steady State Thermal Analysis; Civil Engineering; Structural Engineering
• Online Access: https://scholarworks.umass.edu/masters_theses_2/880; https://scholarworks.umass.edu/cgi/viewcontent.cgi?article=1925&context=masters_theses_2

Thermal bridging can be defined as the phenomenon where a structural element spanning the building envelope acts like a thermal pathway which collects and moves energy (heat) from the interior to the exterior of the structure. CFS construction, due to the high thermal conductivity of steel with respect to its surrounding structural components and repetitive nature of framing, is highly prone to thermal bridging. Thermal bridging significantly alters the thermal performance of wall assemblies. Hence, the objective of this research project was to quantify the magnitude of energy loss through cold-formed steel (CFS) stud wall assemblies at a component level to lay the groundwork for future works that promote sustainable, energy-efficient, and improved building design recommendations. Therefore, a parametric evaluation was performed using ISO 10211:2007, Annex A, conforming heat transfer software Blocon Heat3 version 8 to generate the data required for analysis. 80 unique wall assemblies and the impact of selected parameters on the overall thermal transmittance of the wall assembly were studied as part of the parametric evaluation. The key variables of the study are steel thickness, stud depth, stud spacing, cavity insulation R-value, external insulation thickness (R-value), and fastener diameter and length. Based on the results of the analysis, effects of increasing stud and track thickness, depth, and stud spacing have been discussed in the form of trends in overall heat flow and linear thermal transmittance coefficient values. Additionaly, effects of increasing external insulation have been discussed by addressing changes in heat flow.