Steel-framed buildings: impacts of wall detail configurations on the whole wall thermal performance

This paper discusses the influence of architectural wall details on whole wall thermal performance. Analysis of whole wall thermal performance was done for six light gauge steel-framed wall systems. For each wall system, all wall details were simulated using calibrated three-dimensional finite difference computer modeling. Currently, predicted heat losses through building walls are typically based on measurements of the clear wall area of the wall system using test methods or they are calculated by one of the procedures recommended in the ASHRAE Handbook-Fundamentals. In this paper, 'clear wall area' is defined as the part of the wall system that is free of thermal anomalies due to building envelope details or is thermally unaffected by intersections with other surfaces of the building envelope. Clear wall experiments or calculations normally do not include the effects of building envelope details. For this situation, the thermal properties measured or calculated for the clear wall area do not adequately represent the thermal performance of the total wall system. The main objective of this paper was to find a relationship between structural and material configurations of the steel-framed wall details and the whole wall thermal performance. It was found that even small changes in clear wall or wall detail configuration can bring significant improvements in whole wall thermal performance. Also, this research confirmed that wall systems using steel framing that incorporate wood components are much more thermally effective than conventional steel-framed wall systems.