Volume 37, Issue 6, June 2002
The Sky's No Limit
Skylight Manufacturers Push Themselves to the Max with Challenging Installations
The Milwaukee Art Museum used skylights developed by Super Sky, to showcase a number of views. At the right is the work of W.S. Nelson (see cover).
When an observer views a newly renovated or recently erected building, he may marvel at the intricacies of the structure-whatever those may be. But, he probably will seldom think about the challenges that were involved in those projects. In the following pages, we decided to look at some of the work involved in two challenging skylight projects.
Tallest Hotel Gets a Facelift
When W.S. Nielsen Co. of Atlanta was contracted to replace the skylight roof system at the Westin Peachtree Plaza hotel in downtown Atlanta, the company may not have been able to foresee all the challenges ahead of it. Despite these changes, the renovation of the 73-story hotel, the tallest hotel in North America, was a resounding success.
The project included the installation of 9/16-inch heat-strengthened, laminated safety glass for the entire skylight replacement. This replacement glass comprised of the following items: a layer of ¼-inch standard tint heat-strengthened, laminated glass; a 0.060 PVB interlayer; and a layer of clear ¼-inch heat-strengthened laminated glass. Additionally, the glass was designed to withstand the loads on an exterior, horizontally sloping surface.
The W.S. Nielsen team included Mike Nielsen, president; Tom Dyson, project manager, and Eric Nielsen, project superintendent. According to Dyson, there were several unique challenges involved with the project, one of which was the fact that the original skylight structure consisted of a true square (at base) to round (at top) design with ever-changing angles and pitch. This creating more than 360 un-square, various pitched openings.
"Because of the varying pitches and sizes per opening, today's manufacturers shied away from supplying replacement domes," said Dyson. "The resulting challenge was overcome in our warehouse while confirming that a flat piece of glass would not lay down on all four sides due to the various pitches from rafter to rafter and horizontal to horizontal. We realized that if we split each opening diagonally, we could create two separate planes and therefore re-glaze the entire skylight in glass."
Another challenge was to go out and field measure more than 360 openings, straight-line dimensions and degree angles in each corner and split the opening size diagonally allowing for glass edge bite and the additional structural diagonal-framing member. "Then we had to find a manufacturer who was willing to fabricate the glass without individual patterns," said Dyson.
As if those items weren't challenging enough there was more. Due to the lack of on-site material storage, all materials were received at the company's warehouse in Alpharetta, Ga. They were then trucked to the site, loaded on an elevating work platform and off-loaded at the site as needed. "This was very labor-intensive as we had to handle all materials at least a half-dozen times before it was actually glazed in the skylight," said Dyson.
The team was responsible for carrying out this project in four quadrants and maintaining safety and debris netting below each quadrant while working in this area as the space below remained occupied throughout the entire contract. The project was complicated further by the fact that every piece of glass was of a different size and had to be cut to fit in the pre-engineered and filed measured openings. At the end of each day all openings had to be sealed off and left in a watertight condition.
The skylight renovation took approximately six to eight months to complete with a crew of six to eight men.
Super Sky Pushes the Limits of Building Technology
The thirty thousand people who attended the opening of the Milwaukee Art Museum late last year were lucky enough to see the monumental addition to the museum that was designed by renowned Spanish architect Santiago Calatrava. While Calatrava is well-known in Europe, this is his first project in the United States.
"It was a very unique and challenging design which pushed the limits of building technology, especially in sloped-glazing construction," said Dick Poklar, director of product development for Super Sky Products in Mequon, Wis.
Super Sky Products was responsible for all of the exterior glazing on the building, including the more traditional skylights on the gallery portion of the building, to some extremely complicated designs at the pavilion end of the building, according to Poklar.
The pavilion featured the prow skylight on the East side facing Lake Michigan and the pavilion skylight—the highest portion of the building which is totally enclosed in aluminum panels and covered by the brise-soliel, an operable sunshade which is opened or closed depending on weather conditions. The pavilion also includes the West entrance, which features a circular glass elevator.
The museum incorporates many unique elements, one of which is curved, parallelogram shaped insulating glass units used on the prow skylight, consisting of two lites of 9/16-inch laminated glass which a ½-inch air space. Due to their size, Poklar said these lites had to be made from three-dimensional templates fabricated in the shop; the glass was fabricated and shipped to the job from Cricursa in Spain. The units utilized a low-E coating and colored PVB interlayers to create the desired performance and aesthetic affect.
Additionally, Poklar said that all of the skylight units were designed for the cold, snowy Wisconsin winters and high winds common at the shore of Lake Michigan. The glass types were chosen to limit heat gain and glare, as well as to control heat loss and condensation.
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