b"SCHCK NORTH AMERICACONCRETE-TO-CONCRETE STRUCTURAL THERMAL BREAKS ARE INSTALLED BETWEEN INTERIOR AND BALCONY SLABS, AFTER WHICH CONCRETE ISPOURED CONVENTIONALLY.Both buildings include multiple balconies, roof decks, verticalgoing to cantilever a balcony from the face of the building. You concrete privacy fins, parapets and eyebrowsall of whichhave a straight edge where you can induce a thermal separation, benefit from structural thermal breaks thwarting thermaland the geometry is straightforward. Because of the exterior bridging. These feature an array of faade materialsstone,articulation of fenestration here, this building has lots of jigs brick, metal panelling, glass, plants overhanging concreteand jogs and inside and outside corners that pose challenges. surfacesarticulating a pleasing profile, but creating a In the initial plan, he recalls, the design team tried insulating complex envelope.the entire structure, including balconies and other exposed With most buildings that are rectilinear on the exterior andportions, but the energy-modelling calculations found that have straight runs of faade, Markulin says, you think you areapproach unworkable. Gronross's group at Morrison Hershfield, the firm that authored the Building Envelope Thermal Bridging Guide (2020), analyzed the initial design with an eye towards Vancouver's performance-based path to code compliance and found ordi-nary insulation inadequate. Linear transmittances like thermal bridging and point loads contribute to the majority of your loss, he says. It's not actually the window-wall values; it's these long horizontal ribbons that wrap around the buildingbalconies, eyebrows and roof parapetsthat pull down the insulation value. They create thermal bridges through the insu-lation on the exterior. Mechanical engineering consultants MCW ran energy modelling for ASHRAE compliance. It came back that the building wouldn't meet code, Gronross reports. When they tried to do the performance-based evaluation, the articula-tion of the building, the complexities, the large numbers of thermal bridges [all contributed to this result.] So the prescrip-tive requirements from ASHRAE 90.12016 were the only option. The performance-based path to ASHRAE 90.1didn't work. Various details evolved for the prescriptive path, Gronross says. External stairs were altered, balconies were changed to roof decks, and structural thermal breaks were incorporated at balconies, concrete eyebrows and parapets. The contractor/developer evaluated several manufacturers of structural thermal breaks, using threshold structural values provided by Kor Structural, and chose thermal break solutions. Without them, he says, the building would not have met code.The concrete-to-concrete structural thermal breaks transfer bending moments and shear forces via stainless steel upper 14 BCBEC ELEMENTSA BCBEC PUBLICATION"