Polycarbonate sheet meets the demands of a “living roof” in a retrofit at the California Academy of Sciences in San Francisco.
Bayer MaterialScience LLC says its Makrolon 15 sheet was selected for retractable panels over the academy's atrium because it is lighter than glass and therefore needs fewer structural supports that are costly and impair aesthetics. The PC sheet replaced the original fabric screen roof system that failed to provide enough protection against weather.
Bayer, with its U.S. office in Pittsburgh, Pa., said another benefit is PC's high resistance to breakage that would be a safety risk. Potential roof failure is an issue in the earthquake-prone region. Clarity, UV resistance and scratch resistance were other properties beneficial to this application, according to Bayer.
The retractable atrium roof comprises two sections measuring 18 feet by 48 feet. Each section consists of six panels supported by eight 66-foot long rectangular tubes that span the roof opening. The tubes arch up eight feet at the center of the roof. When closed, the roof's two panels meet at the center of the arched tubes. An edge flap over the center provides a weather-tight seal.
The California Academy of Sciences is a scientific and educational institution with a wide range of exhibits and nearly 46 million scientific specimens from around the world. The academy's building earned the highest rating, Platinum, from the U.S. Green Building Council in its Leadership in Energy and Environmental Design (LEED) program.
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