• Field Notes 23.05.2012

    So much of the discussion in the architecture and glazing industries is on solar, solar, solar. That’s a good thing, since using the sun to generate electricity is clean and renewable. But, there’s one aspect of solar energy that sometimes gets missed (to the chagrin of building owners). From sunburns to ruined art treasures, some building’s glazing reflects vast amounts of sunlight in undesirable ways. Read on for some cautionary examples.

    When I moved to Dallas in the early 1980s, there was a building complex with twin office towers and a hotel between them sheathed in highly reflective gold glass. During the day, all you saw was the gold glass. The office buildings were square and oriented northeast/southwest, about 45o off what would be a typical north-south axis.

    Whenever I had to drive the adjacent freeway, it was easy to be startled by the glare from those buildings at certain times on sunny days. Drivers would be in and out of the glare before realizing it, and it never hit you square in the eyes, but for the first few times the flash was a bit unsettling.

    Urban legend has it a 50-story office tower in the northeast U.S. using silver glass had the same glare issue. One of the building’s neighbors sued since the glare imposed an additional thermal load that their HVAC system couldn’t keep up with. Supposedly, the neighbor won the lawsuit. I know a few people involved in the project when it was built, but they are not at liberty to say who was ultimately held responsible: the architect, glass company or any of the other players.

    So it was with some understanding (and amusement, too) when I read last summer that one of the new City Place developments in Vegas had an undesirable attraction: due to the inward curving surface of a south-facing tower, people near the swimming pool were getting a little extra crispy in their sun tanning sessions. Terms not normally associated with curtain walls, such as “death ray” and “solar convergence zone” were being tossed about (see for example: http://www.aolnews.com/2010/09/28/hot-architecture-vegas-death-ray-singes-tourists/).

    Between the geometry of the building façade and the sun’s movement across the sky, a magnifying glass of enormous proportions made ants of some sunbathers. Any critters in the vicinity could get fried quickly if they weren’t paying attention, deck chairs were too hot to touch, let alone lie on, etc. I wonder if they had to run the pool water through the AC chillers, too?

    Then my Kansas City-based son sent me this link about a project in Dallas suffering from some of the same effects, only the glass wall curved outward instead of inward as the Las Vegas building does, but it is still having disastrous consequences on a neighboring museum and sculpture garden. http://www.dmagazine.com/Home/D_Magazine/2012/May/Museum_Tower_The_Towering_Inferno.aspx.

    The Dallas museum was designed by a world-renowned architect. If you’ve never worked on a museum, from a glazing standpoint, they are one of the most technically challenging building types. Although it’s desirable to show artwork in as much natural light as possible, direct sun can degrade paint, and other materials. Architects take a great deal of care to ensure expensive artwork is naturally lit, but also that it does NOT get any direct sun. In this case, the architect designed a specialty “louver” (if you will) that’s aluminum and egg-shaped; the openings are specifically oriented to the degree, minute and second; and the opening is sized so that no direct sun can get through the curved glass roof. It’s a neat building; I got to go on the roof once, and could appreciate exactly what and why the architect had done what he had done.

    All sorts of design permutations, modeling and testing confirmed the design worked. It was even recognized that any building built on the adjacent properties could lead to disaster. The museum got an agreement from the property owner to do just that: limit the amount of reflected sun off any future development. That’s when the whole thing went to you-know-where in a hand basket.

    That agreement expired, and the architects (it appears several different firms or individuals were involved) for the new building apparently weren’t brought into the loop or overlooked the past agreement during the course of drawing and plan development. Lo and behold, reflected sun off the new project is either ruining what was considered a world-class museum and/or killing the landscaping in the exterior garden. The patron the museum is named for has passed away, and the foundation left in place to run it is having issues with enforcing the expired covenants.

    And, if you think this issue doesn’t trickle down to us small folk: last but not least, here’s an article about reflected solar energy from a home’s windows melting a neighbor’s vinyl siding: http://www.greenbuildingadvisor.com/blogs/dept/musings/window-reflections-can-melt-vinyl-siding?utm_source=email&utm_medium=eletter&utm_content=20120425-heat-loss-calcuations&utm_campaign=green-building-advisor-eletter. The builder says it’s not his fault; the material suppliers aren’t talking.

    Surely, in all these cases, there are some lawyers talking. And somebody’s gotta pay, right? Where is this going to lead, besides the courthouse? Given our ability to animate and create three-dimensional models, coming up with a computer simulation of what one building does to its surrounds can’t be far away. Wind tunnel studies recreate a project site and by using historical weather data wind loads are determined. If the reflective properties of materials can be quantified, the models have the potential to recreate real-world conditions.

    Sunlight models could do the same thing since they create the basis for reduced lighting requirements inside a building. Will materials selected for an exterior wall need to be graded for light and solar energy reflectivity? That may have to happen in order to make computer simulations work. The need to analyze how exterior wall materials reflect the sun’s energy, and the impact that has on neighboring buildings, homes or institutions can’t be far behind, especially if any the above projects or other cases set precedence as the lawsuits make their way through the courts. If the designers aren’t fully aware of it, will the glazing industry have to be the one to speak up?

    Given that there’s now more emphasis on the impact of resources FROM and ON the environment, creating models to predict reflective energy, much like thermal modeling, would seem to be a natural outgrowth of how buildings react and behave in the sun, and their impact on their surrounds. It’ll be interesting to see how this sorts out. Any predictions?

    Posted by Blogger @ 9:29 am

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USGlass Magazine

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