Morrison Hershfield will be presenting two sessions at this year’s Facade Tectonics World Congress Conference in Los Angeles.
Stéphane Hoffman, Senior Building Science Specialist and Facade Engineering Practice Lead, will be presenting Energy Code Implications for Spandrel Design during Session 1 at 8:30 am on Monday, October 10th.
Recent energy codes have raised the bar in terms of performance expectations for the building envelope. These new codes can challenge the performance of traditional unitized glazing systems. Especially challenging is the opaque wall U-values based on the assumption of continuous insulation for metal framed assemblies. The implication of glazing ratios on glazing system U-values and in particular recent findings of spandrel performance will be summarized. A comparison of traditional parallel path (or area weighted approach) analysis and new approach to considering the effect of lateral path using 3D thermal modeling will be highlighted. The results of comparison of these two approaches in relation to guarded hotbox testing will be presented. Examples from the ASHRAE 1365-RP research report on the impact of 3D thermal bridging and the BC Hydro Envelope Thermal Bridging Guide will be used to illustrate the impact for traditional spandrel design when the effects on interface details are accounted for. Looking beyond “code compliance” examples using the latest 3D thermal modeling and innovative materials will demonstrate how the effect of thermal bridging can be mitigated. Proposed methodology to specifying spandrel performance in light of the shortcomings of current modeling techniques will be outlined.