When originally built, Michel Jaspers' design for the headquarters of KBC's banking operations in Leuven, Belgium, centered on an atrium that connected the company's various departments. Impressive skylights offered abundant natural light to create "an open and green central meeting point," according to the architect's firm. But some years later, changes in the corporate structure, including a large merger, created a significant problem as the building's occupancy swelled from 1,850 to 2,300.
 
To accommodate the greatly increased number of employees, the space plan was adjusted, placing an open arrangement of desks in the atrium space below the skylights. Workers at these stations soon began to complain of eye strain due to serious light reflections on their computer screens. To address the problem, the company brought in architectural firm AR-TE, who worked with solar-control experts at Hunter Douglas' Helioscreen unit to design a solution. Together the team ended up creating a solar-control system of 120 automated skylight shades (details below) - but this solution came only after an intense study of the space itself.
 
AR-TE's first challenge was simply to quantify the problem, which began as only a long list of employee complaints. They began by dividing the building into 41 zones. They then conducted a detailed analysis of each zone to identify the critical angle of incidence of sunlight passing through the windows. This determined the actual problem zones and defined the times when it occurred by both hour and month. From this study, AR-TE identified the number, size, and location of the sun screens, as well as when they would need to be activated.
 
The unusual complexity and dimensions of the building and the shape of the glass in the roof combined to make the shading design a challenging project of exceptional magnitude. The team from Hunter Douglas custom-engineered a system of 120 fabric panels that move across the inside of the glass surfaces along stainless-steel cables. Due to the size of each shade - about 3 by 14 meters each - thorough prototyping and testing was required to ensure the guide cables operating mechanisms would pull the shades across the inclined glazing. Prototyping also included a variety of tests in various thermal conditions, ensuring shades would retain their shape while being retracted.
 
A sensor mounted on the roof of the building controls the shades. It measures the intensity of light in three directions, then compares ambient light against preset parameters. Whenever light intensity exceeds the maximum limit for longer than 1 minute, the sunscreens roll out, stopping at one of three possible positions relative to the position of the sun. When light falls below a minimum limit for more than 20 minutes, the sunscreens retract. If desired, override controls allow building managers easily to adjust the system limits, or the system can be adjusted remotely by computer. In the event of a fire or other emergency, the building management system takes control of the system to respond appropriately.
 
Today, the irritating reflections that made work difficult- and sometimes impossible - have been eliminated, without sacrificing the natural light that the building's occupants can enjoy.