Swiss university encourages iconic architecture and benefits from solar protection.
The Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland, places an emphasis on iconic design in order to develop the architectural charisma it needs to prevail in the globally competitive university sector. The exterior renovation of the existing Institute for Mechanical Engineering building, now known as the Pôle de Bio-Ingénierie, is the latest evidence of this strategy.
Designed by Dominique Perrault Architecture, Paris, the renovated exterior owes its unique appearance to a three-dimensional zig-zag façade consisting of 630 horizontally sliding solar-protection elements made of metallic fabric from GKD Metal Fabrics, Cambridge, MD.
State-of-the-art offices, seminar rooms, and laboratories make up the more than 32,000- sq.-ft. building used for interdisciplinary research. Perrault designed the four-story façade as part of his urban reorganization of the campus, which underlines the new dynamic of the center. The individual panels form a vertical and horizontal zig-zag pattern spanning the entire building like awnings. Panels are alternately affixed at the top and bottom, and are made of natural-colored, anodized Escale aluminum fabric, which is fixed in place by means of a stable frame construction using clip bolts.
The panels are arranged in groups of three, with two of each group being motorized and moving on rails behind the fixed element in a telescopic manner. When they are closed, the panels guarantee efficient solar protection, free workplaces from the glare of the sun, and grant unhindered views of the outside surroundings. Yet the open structure of the fabric also allows natural daylight into rooms and enables natural ventilation, thus making the building a pleasant environment for employees. This, in turn, increases productivity and minimizes energy requirements for artificial light and air conditioning.
In terms of the holistic sustainability of the building, the panels can be adjusted on a room-by-room basis according to room usage and time of year. Thanks to the protection from undesired heating through the sun in summer and the use of heat generated by sunlight entering the building in winter, the fabric supports energy-efficient climate management throughout the building.
For Perrault, however, the decisive factor in the choice of material was its special visual appearance. Its spirals, each measuring 7-mm wide and 150-mm long, reflect sunlight particularly intensively and lend the panels a Mediterranean lightness despite the solid nature of the material. This effect makes them the perfect means with which to express Perrault’s intention to create a building without visible walls. Even their subtle presence transforms a place without dominating it, while engaging in permanent exchange with their surroundings. This makes the building a backdrop and the star of the show–and exactly this effect is the reason why Perrault has already used this fabric type in many of his projects.
For the ground floor of the Pôle de Bio-Ingénierie, Perrault chose the Escale 7 x 2 fabric, whose 2-mm-thick flat wire offers greater protection from vandalism. He opted for Escale 7 x 1 for the three upper stories–the same mesh type that was used in another building just a stone’s throw away. The entrance in the middle of the elongated construction faces toward the Rolex Learning Center, visually breaking the bidirectional zig-zag structure of the panels in three vertical rows through an enlarged projection angle. The groups of three elements in this area appear to have been pushed upward by the hand of a giant, an impression further strengthened by the lowest three groups of panels fixed at different angles. This produces an overhanging canopy divided into three parts seemingly hovering over the entrance and underlining the light and airy feel of the façade.
For static reasons, a stainless-steel Escale fabric was chosen for the entrance area. The delicate, lateral bars and thin, round supports upon which the frame is mounted on one side also carry enormous loads at the canopy. In order to allow the snow load that is typical of the region, additional central-fastening fixtures were added to the panels at the overhang and fixed to the fabric using special brackets. Although the complexity of the façade geometry and the size of the partially motorized individual elements place tough demands upon the bearing structure, Perrault made a conscious decision to go without rear anchoring of the panels. Instead, his design envisages a frame structure that carries the entire load of the frame and fabric. Because the building is situated in a mountainous region in the immediate vicinity of Lake Geneva, it was important to take increased wind and snow, as well as freezing temperatures into account for the static calculations. In order to verify the static planning, Perrault subjected three prototypes of these elements to real conditions for one year.
Thanks to its visually subtle fastening means, the finished façade reminds a viewer of a fragile house of cards. This experimental character is a stark contrast to the technically sophisticated feel of the metallic shell. CA