July 30, 2014

Case Study: Exceptional Lighting Turns a Library Inside Out | Library by Design

ljx120502lbdWhatsHot30 Case Study: Exceptional Lighting Turns a Library Inside Out | Library by Design

The goal of the new Tenley-Friendship Neighborhood Library in Washington, DC, which opened in January 2011, was to give neighborhood residents a “grand, well-lit, inviting” place—a “fantastic library where people would want to spend time,” says Kim Fuller, District of Columbia Public Library’s (DCPL) project manager, who oversaw the library’s construction.

The 22,000 square foot library’s architecture, with floor-to-ceiling windows overlooking busy streetscapes and trees, provided the framework for this concept. Strategic lighting design did the rest, with $600,000 from Tenley-Friendship’s budget of $11 million.

“The intent was to have it feel transparent,” says Hayden McKay, principal at Horton Lees Brogden (HLB) Lighting Design, which conceived the lighting scheme. “We wanted the library to be as daylit as possible and also have a connection to nature.”

The lighting strategy also provides a model of energy efficiency, thanks to strategic sunlight harvesting, sun control, occupancy sensors, and other features that helped propel the library to Leadership in Energy & Environmental Design (LEED) Gold ­certification.

DESIGNING IN VIEWS

Mindful of DCPL’s commitment to creating a community icon with an urban street presence, McKay and colleagues strove to enhance the library’s open, inviting architecture and to bring in the natural cycles of daylight. HLB installed vertical, copper-colored fins along some façades to shield patrons from the sun, while also framing dynamic views onto the street that shift as patrons move through the space. The copper hue also enhances sunlight differently depending on the position of the sun.

These vistas also “allow you to re­direct your focus after you’ve been looking at a computer screen,” says McKay, a switch that relaxes and refreshes the eyes. “It’s not just daylight itself that’s important to people but the view. The windows tell you about the time of day, the weather, the climate, what’s happening on the street.”

In the center of the library, an enormous, bow tie–shaped skylight above a large atrium feeds light to the main reading room. Direct light makes one area “feel like an outdoor patio,” McKay says, an ideal environment for sun-loving patrons (though the collection throughout is shielded from damaging UV rays).

For a more whimsical effect in the children’s area, “we use circular fluorescent fixtures in varying sizes—three-, four-, and five-foot diameter, scattered in a playful way,” says McKay.

OPEN FOR BUSINESS

Multiple photo sensors in the library reduce electrical light output depending on the level of natural light. McKay estimates that the library lights typically dim to five percent during the day. Photo sensors automatically turn off the lights in empty conference rooms.

Throughout the library, HLB envisioned “indirect, soft uniform lighting” to complement the library’s airy design and provide visual comfort. Cantilevered fixtures over the stacks offer a diffused sense of light, as does indirect light that bounces off the open ceiling. Collectively, McKay notes, this “illuminates the whole space so you don’t get a feeling of being in a CVS, with exposed lights all day long.”

There is one catch to all this energy efficiency, though: because so many lights are off, “people aren’t always sure the library’s open” during the day, McKay says. To “make it inviting,” HLB installed six long, candle-shaped pendants in the stairwell that stay on during library hours. Though only 13-watt fixtures, they add a critical “little bit of sparkle.”

“People can stay inside for extended periods of time as long as they have the connection to the outdoors,” observes McKay. As testament to this, Fuller notes, “people are there every hour that the library is open. That was not the case with the old [building].”

“It may sound elementary, but people are grateful for well-lit spaces,” adds Fuller, noting that “deferred maintenance” in the previous branch led to poor lighting. Now, “you don’t have go to around the corner and worry that the light is out.”

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