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    - image courtesy Knippers Helbig

The Steven Holl Architects-designed Nancy and Rich Kinder Building at the Museum of Fine Arts, Houston is clad with half-tubes of translucent glass that reduce solar heat gain by an estimated 70 percent. “Steven always had this idea of having a cold jacket outside the building to improve the performance and to articulate the facade,” says project architect Olaf Schmidt, “but the specific idea for the glass tubes came about when plexiglass rods were used in a study model during the design.” These rods inspired a full-tube design that proved too costly and difficult to implement and clean, so the architects pivoted to the half-tubes we see today — a solution that came with its own set of challenges.

– image courtesy Knippers Helbig

Holl’s team partnered with German engineering firm Knippers Helbig to design an assembly that is elegant and sturdy. Galvanized steel outriggers anchored to the building’s concrete structure support a series of steel shelves upon which the weight of the glass tubes rests. Structural silicone attaches the glass half-tubes to aluminum clips that bolt to the steel frame and absorb lateral loads. Within the sizable cavity between the tubes and the concrete, there is also a catwalk for maintenance and cleaning.

Manufacturing the glass half-tubes also presented a challenge. Each half-tube, of which there are about a thousand, takes multiple hours to form, starting as a flat piece of glass that is slowly heated until it droops under its own weight. After bending, pieces are laminated together in twos. Due to the large scale and quantity of the bent glass, manufacturing capacity became one of the selection criteria for the glass suppliers; the firm that was awarded the contract after supplying mock-up pieces, Shennanyi Glass in China, had the oven capacity to produce the tubes within the construction schedule.

White interlayers and an acid wash give the glass half-tubes a satin-like finish that exhibits a soft luminosity in bright sunlight, much like the clouds that inspired the building’s form. At night, they emit a fuzzy, mysterious light. 

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