Steve LeBlanc, courtesy of Technoform

The new 707 Fifth (AAA) office tower in downtown Calgary, Alberta, features a curved glass appearance with high energy-efficiency and a comfortable interior. In spite of the location’s cold climate, the 27-story, 564,000-square-foot building met its energy targets. The project, designed by Skidmore, Owings and Merrill (SOM), is designed to achieve LEED Gold certification through the Canadian Green Building Council.

The building’s façade combines convex and concave forms to shape elliptical and undulating elevations. The floor-to-ceiling glass was designed to maximize internal daylighting and comfort, minimize unwanted solar heat gain and heat loss, and provide panoramic views of the city and the Rocky Mountains.

The curtainwall relies on Tianjin North Glass’ (TNG’s) bent, triple-pane insulating glass units (IGUs) with two low-E coatings from G-Crystal Glass Group. Technoform’s warm edge spacer, TGI Spacer M, separates the three lites of glass, creating an insulating barrier at the perimeter of the IGU to improve thermal performance.

Steve LeBlanc, courtesy of Technoform

Construction manager EllisDon worked closely with Contract Glaziers West Inc. to engineer the custom, high-performance, unitized, structurally glazed, aluminum-framed curtainwall system, and to manufacture and install it to precise specifications.

In total, TNG supplied 220,000 square feet of glass to Contract Glaziers West, which fabricated the curtainwall in its Windsor, Ontario, facility then transported the system to Calgary for installation on the project.

“TNG was one of the few glass manufacturers willing to accept the challenge of producing IGUs with custom low-E coatings, such that they looked the same whether in the concave or convex orientation,” says Technoform’s Helen Sanders.

“Using Technoform’s spacer for this application came from a recommendation by the Tianjin North Glass team,” adds Contract Glaziers West’s Steve LeBlanc. “We affirmed their preferred spacer solution via our thermal modelling for the project, thus establishing that it would provide the performance values we required.”

The thermal performance requirements of 707 Fifth included stringent whole unit U-factors of 0.91 W/m²K (0.16 hr/ft²F), according to Dirk Schulte, formerly with TNG.

Davide Colonna on Unsplash

Before beginning construction in 2014, EllisDon’s virtual design and construction team produced 3D conceptualizations using building information modeling (BIM) tools. According to the construction manager, this visualization of the project led to “a complex, yet achievable coordination process,” guiding the way to its successful conclusion.

Reiterating the key aesthetic goals for the 707 Fifth, LeBlanc says, “The façade had a geometry of both concave and convex radius glazing, as well as the east and west elevations’ inverted slope from ground level to the top of the building. All flat and curved glass had to match in color and performance as per the design specifications.”

“The overall exterior visible quality and glass flatness was a huge concern. Therefore, the outer lite was specified as 2- by 8-mm laminated glass to lower the risk of visual distortions – all intended to provide a higher level of flatness on the exterior surface,” adds Schulte. “… The architectural team at SOM also was very concerned about color matching between flat, concave and convex shaped panels.”

Chad Koski, courtesy of Technoform

SOM’s associate Eric Pasche also adds, “Laminated glass was also preferred by the client to provide an additional level of safety in the event of glass breakage.

TNG produced the units, working closely with Clarity Architectural Products’ inspection process and team.

“The owner required a 100% inspection of fabricated glass, which TNG accepted and welcomed to prove the high level of production quality and workmanship on the final glass. Clarity managed to keep all the loose ends together to develop, produce, inspect and deliver a tailor-made product from China at the highest aesthetic and quality standards,” says Schulte.

Anticipating the needs of Contract Glaziers West, TNG and Clarity delivered the glass prior to installation. The project was completed on time for a grand opening in April 2017. Total construction costs are estimated at $200 million.