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OCTOBER 2015 | 19 PHOTOGRAPHY COURTESY INLAND GLASS & ALUMINUM LTD. Curtain Wall & Window Wall The new Kelly Ramsey Tower in Edmonton, a 28-storey office tower in the down- town financial core, is also reflective of some of the current trends in curtain wall and glazing, says Gary Lawrence, a partner at Inland Glass and Aluminum Ltd. "It's a high-span curtain wall office tower. The all-vision glass gives it a nice, sleek appear- ance," he says. Lawrence goes on to say that the industry's push for thermal performance enables curtain wall systems like the one used for the Kelly Ramsey to achieve U-values of around 2.5. A tactic that Paul Arnold, general manager at Starline Architectural Windows, points to involves finding a great insulation solution for the spandrel sections. Polyisocyanurate insulation and larger thermal breaks in the aluminum frame are two options; Dow Corning Building Insulation Blanket is another. A company bro- chure says it is rated R-9.8, above that of polyisocyanurate, the next highest rated product, at R-6. "It is expensive, though. But as more gets used the price will come down, like when double glazing came in," Arnold says. Another trend he notes is that companies are opting for low-E coatings with a reflective attribute "rather than tinted glass. The cost is lower. Also, the tinted glass only affects the solar heat gain coefficient, not the U-values, but low-E does affect U-values. Now, you can use low-E glass that includes a reflecting colour," Arnold says. The two dominant trends in the curtain wall sector these days – requirements for better thermal performance and demand for the all glass look with larger mod- ules and window panes – would seem to be pulling in opposite directions, and there doesn't seem to be any resolution in sight. Instead, the twin trends are pushing costs up. "The price of raw glass from a U.S. float plant has gone up 50 per cent in the last two years. At the same time, we have a lower Canadian dollar as we're pushing for better thermal performance," says Mark de Goutiere, a partner at Glastech Glazing Contractors Ltd. The giant U.S. factories are about a mile long and melt silica of various kinds which sits, or "floats," on molten tin to produce the smooth finish we associate with modern glass products. Likely further helping to push glass prices up is the fact that two of these facto- ries, which are very expensive to build, have been mothballed for the time being, choking off about 25 per cent of raw glass manufacturing in the U.S. "The U.S. facto- ries are old and some have needed major shutdowns," de Goutiere says. This has all coincided with the uptick in market demand for glass on the continent. Other factors are also boosting prices, he says: "As architects are pushing the design envelope, glass sizes get bigger and thicker. At the end of the day, users pay more [heating costs] for poor thermal performance." The Kelly Ramsey Tower.

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