Some buildings are known for their architectural form, some for their use of materials, others for their quality of light. In the case of the Kimbell Art Museum in Fort Worth, Texas, designed between 1966–72 by architect Louis Kahn, it’s the perfect triumvirate. How then, could anyone think of disturbing this masterwork, which has secured its place as an icon of modern architecture? The dilemma of how to approach architectural expansion has become more pressing in recent years as a generation of buildings come of age and the institutions they house have come to exceed their spatial limits.
Like many art museums, the Kimbell has faced spatial constraints in its galleries for years. It has not been able to display the full extent of its collection and traveling exhibitions at the same time. As a result, it has had to house much of its permanent collection in storage while special exhibitions were occurring.
In 1989–90, the museum pursued an expansion plan with a design by Mitchell/Giurgola Architects. But the proposal, which called for replicating Kahn’s architectural bays with their distinctive cycloidal concrete barrel vaults, met with significant outcry from the architectural community and even Kahn’s daughter, Sue Ann. Unnerved by this public relations fiasco, the museum shelved the plans. The need for more space, however, remained.
Jump ahead almost 17 years to 2006. The Kimbell Trustees, who had since gotten Sue Ann Kahn on board with expansion by introducing the idea to construct a separate building across from the existing museum, approached architect Renzo Piano and his firm Renzo Piano Building Workshop (RPBW) with the commission. Piano was reluctant at first, as he saw what had happened during the last go-around. More importantly, as a young architect, he had worked in Kahn’s office in the early 1960s, and this was someone’s work whom he admired.
In time, though, Piano accepted the challenge and began work on a preliminary design, but there still remained the issue of where this new addition would be located. The museum had purchased land across from its rear entrance. Then, when it was suggested that the new building be built across the garden that faced the front of the Kahn building, the expansion project was infused with a new momentum.
Piano’s design for the new building is respectful of Kahn’s work, drawing inspiration not only from its architectural organization and attention to materials and textures, but its masterful use of natural light, which infuses the interiors with a sublime quality. And just as Kahn worked with lighting designer Richard Kelly to develop a lighting strategy for the project, so Piano worked with the lighting group at Arup on the illumination design of the new addition. It is not the first time RPBW has worked with the lighting team at Arup. The two firms have collaborated on a number of art museum additions over the past decade, including the High Museum in Atlanta, the Art Institute of Chicago, and the Isabella Stewart Gardner Museum in Boston.
At the Kimbell, the new building, referred to as the Piano Pavilion, houses gallery spaces, a 298-seat auditorium, classrooms, the education department offices, an expanded library, art preparatory areas and storage, a café, and a gift shop. It faces east and sits exactly 65 yards wall-to-wall from Kahn’s building.
The magnitude of the design challenge goes well beyond the architecture. Trying to create a lighting scheme, and particularly a daylighting scheme that was the match of the original building was no easy task. Kahn and Kelly, along with the assistance of Edison Price and Price’s computer consultant Isaac Goodbar, devised a daylighting system for the galleries that has earned its place as one the gold standards in lighting design. Kahn wanted there to be indirect sunlight in the galleries. Given the Texas climate, however, the designers had to be extremely careful about how much light would be allowed into the space. What Kahn hadn’t figured out was how to diffuse this light.
After in-depth research and elaborate lighting calculations, the team established the exact position and angle that a reflector would need to sit below the curved ceiling in order to properly diffuse the light. This passive system allows light to enter through a slot in the barrel-vault ceiling and then hit the main surface of the polished-anodized-aluminum reflector. (Kelly had suggested the use of a perforated metal screen, commonly found in commercial light fixtures.)
Most of the light is bounced up to the concrete ceiling vaults while a small amount is allowed to diffuse through the perforated reflector into the gallery below. Kahn is said to have called the reflectors “natural-light fixtures.” A splayed armature suspends below the reflector (which follows the reflector’s reverse curve) with two rails of tracklighting to provide complementary electric light. Additional natural light enters the space at each end wall through a narrow, glass light-band that follows the curve of the barrel vault. The outcome of this light manipulation is a slivery, diffuse light that creates an environment that respects the sensitive artworks on display and connects the museum visitor to the outside.
To tackle the lighting in the new Piano Pavilion, the Arup team knew they would have to make a careful study of Kahn and Kelly’s work, not just in terms of the technical components but the qualitative as well. “We did a thorough assessment of the Kahn building looking at what made the lumen levels, what the distribution of the light was, and what was the luminance distribution on the surfaces of the gallery spaces,” says Arfon Davies, associate director of lighting in Arup’s London office who led the lighting efforts alongside associate lighting designer Giulio Antonutto. “It quickly became apparent that the feeling of light there is much more significant than the actual amount of daylight in the space. It’s a very clever trick; when you enter the gallery space you feel the presence of daylight is much more significant than it actually is. That was something that we really felt was an important characteristic of the Kahn [building] that we wanted to try [to use] and form the design of what we would do in the Piano Pavilion.”
With a nod to the form and materiality of Kahn’s building, Piano’s design is respectful, yet consistent, with his own architectural vocabulary of glass, wood, and steel. The building’s 300-foot-long east façade, which faces the Kahn building, is divided into three bays: a recessed glass entrance and a wing to each side finished in a light-gray concrete. The entire elevation is capped off by the glass roof structure supported by Douglas fir wood beams.
According to Davies, Piano wanted a lighting design that was adaptable and tunable. To that end, the gallery lighting marks a milestone for the RPBW–Arup team. It is the first time they used an all-LED solution. The design of the space, with its 29 pairs of 100-foot-long laminated wood beams, allows the galleries to be completely open and a system of movable partitions to be rearranged based on the needs of the exhibit. The space can be lit primarily with daylight, or can be changed to be lit primarily lit by electric light. The spotlights, outfitted with 24W 3000K LED modules, and other building systems such as sprinklers and security cameras are run on tracks positioned in between the beams to keep the ceiling plane as clean as possible.
Whereas other roofs that the RPBW–Arup team have collaborated on consist of multiple layers, the Piano pavilion’s roof is a single layer that performs an array of functions. Sitting just above the glass is a photovoltaic louver system. Its first job is to control the amount of light entering into the space, and it can be either fully closed or open to any position between zero and 45 degrees. In the case of serious weather, such as hail, they rotate and fold over to protect the glass roof structure. The PV cells within the louvers generate enough power to meet about 70 percent of the lighting energy needs for the building, Davies says. The louvers also keep sun off the glass, and each module is individually controlled by a dedicated louver control system.
On the underside of the skylight glass, which has a white interlayer with an acid etch on the inside surface for a more matte finish, a scrim further assists in diffusing the light. (The scrim does not exist in the lobby so that the wood beams can be seen.) Custom 10.5W 3000K LED fixtures with an adjustable shield are tucked up out of sight above the wood beams to uplight the glass ceiling and increase the luminance at night. “The intention was to avoid the ceiling becoming a black void at night, and to reveal the volume above the scrim that can be experienced during the day,” Davies says.
Another area where light plays a significant role is in the auditorium. Natural light permeates the space through a light well that sits behind the stage and its rear glass curtainwall. At the base of the curtainwall, a line of shielded wallwashers keeps the source out of view from the audience and the performers.
Different, yet rooted in the same desire to create a serene gallery experience, the new Piano Pavilion at the Kimbell Art Museum offers a contemporary interpretation of how to marry light and architecture.
Project Renzo Piano Pavilion, Kimbell Art Museum, Fort Worth, Texas
Client/Owner Kimbell Art Foundation, Fort Worth, Texas
Design Architect Renzo Piano Building Workshop, Genoa, Italy
Executive Architect Kendall/Heaton Associates, Houston
Lighting Designer Arup, London
Project Manager Paratus Group, New York
Construction Manager The Beck Group, Dallas/Fort Worth, Texas
Structural Engineer Guy Nordenson and Associates, New York
M/E/P Engineer Arup, London, with Summit Consultants, Fort Worth, Texas
Project Size 101,130 square feet
Project Cost $135 million
Code Compliance ASHRAE 90.1-2007
Watts per Square Foot 1.1 Manufacturers/Applications
Acuity Brands/eldoLED DMX LED driver for fixture in beam assembly
Bega exterior site lighting
Cooper Lighting/io interior ambient lighting in beam assembly
iGuzzini above-ground tree lighting, auditorium house lighting, and linear fluorescent lighting in offices and education studios
Lighting Services Inc gallery tracklighting
GIG motorized photovoltaic louvers on the roof
Mermet roller shade fabrics
Nysan roller shade system
Philips Strand Lighting lighting controls
We-ef exterior inground uplighting
Xicato LED modules for gallery tracklighting