More than the package

August 11, 2010

Like a futuristic tree house, Tetra Pak's U.S. headquarters sits nestled among 11 acres of mature trees in Vernon Hills, Ill., a suburb north of Chicago. Resting as close as 10 feet from full-grown red oak and hickory, the 100,000-sq.-ft. building looks as if it has grown up with the forest.

The fast-track design/build project, which took a mere 16 months to complete, was preceded by a 10-year search by owner/developer Van Vlissingen & Co. of Lincolnshire, Ill., for a tenant that was willing to build a smaller building and pay higher rent to preserve the most heavily wooded site in its 350-acre Corporate Woods business park. Tetra Pak, a Swedish manufacturer of packaging for liquid foods, was a perfect fit. Although it originally intended to construct a much bigger building, the company agreed to downsize its plan to include a two-story, 60,000-sq.-ft. office wrapped around a 40,000-sq.-ft. warehouse. The company also agreed to pay a rent premium of approximately 10 percent and signed a long-term lease.

Van Vlissingen led the design/build team, which included Chicago-based architect Solomon Cordwell Buenz & Associates (SCB), Schaumburg, Ill.-based general contractor Power Construction, Park Ridge, Ill.-based structural engineer Robert L. Miller & Associates and mechanical engineer V.A. Smith & Co. of Wheeling, Ill.

One with nature

Tetra Pak wanted a building that was as close to nature as possible. To accomplish this, both design and construction incorporated measures to minimize disturbance of the trees and surrounding landscape.

First, each tree was identified by species and size. SCB's footprint of the building and parking lot was then molded around the largest trees.

Topsoil from the footprint area of the building and parking lot was removed and used as landscaping mulch elsewhere on the site, retaining the area's natural woodland seeds. Also, 22 linden and hickory trees located within the footprint were removed, stored and later replanted on the site.

Even after the footprint perimeter was finalized, says Mark Polinko, vice president of design for Wauconda, Ill.-based landscape architect ILT Vignocchi, last-minute adjustments were made to accommodate trees that were not accounted for in the survey.

"As we worked around the corners of the footprint, we found there were some additional trees that could be saved, especially in the parking lot," adds Polinko. "I estimate that these last-minute adjustments saved six more trees."

The design of the building was also changed to spare trees. For example, says Polinko, the building's outdoor courtyard was originally intended to be an enclosed interior space.

Construction began with the paving of the parking lot, which provided the only access to the site. To avoid damaging the native landscape with heavy equipment, the building was essentially assembled from the inside out. Power Construction erected the steel-frame offices and precast-concrete warehouse using a crane set up within the warehouse's footprint.

Other tree-saving measures during construction included pumping concrete to the building from off site rather than delivering it by truck, auguring underground utility piping under the tree roots rather than trenching, and delivering the HVAC components via helicopter.

Simple, open design

Tetra Pak wanted the building to incorporate many of the characteristics inherent in its other locations-including vibrant interior colors and wide-open work spaces-which became the framework for SCB's design.

"When I heard that Tetra Pak wanted open space without interior partitions, I said, 'Now we are freed from having a ceiling [on the second floor],'" says Martin Wolf, project architect with SCB. "Instead of covering the metal roof and its steel support components with drywall, we chose to fully expose the metal."

The building's structural system is exposed inside and out. Steel and aluminum sunscreens along the south and west façade jut out 10 feet from the roof, while the roof-supported by two perimeter steel columns-extends 20 feet outside the building's envelope over the main entrance. The design creates a canopy effect that is meant to echo the surrounding trees.

The roof slopes upward at a 3-degree angle from the center of the building outward, creating more open space and allowing additional daylight to enter. Supporting the roof are king-post trusses that span 50 feet, creating large column-free areas. Because of the relatively small size and height of the building, fireproofing was not required. The exposed metal was simply painted in a neutral white hue.

The office has just seven private offices, some of which are housed in 11-ft.-high pavilions, so as not to interrupt views of the exposed roof, which rises up 20 feet above the second floor.

Other enclosed offices, conference rooms and break rooms have at least one glass wall to maintain a sense of openness. Many have two glass walls to allow views of important interior design elements or of the outside. For instance, several conference rooms at the center of the office on the first and second floors have two glass walls, exposing a two-story, bright-red, curving wall that runs parallel to the conference rooms.

"The interior design is a series of see-through layers," adds Barry Bebart, interior architect with SCB. "The intention was to be able to see everything that's happening in the building."

Natural light entering through the low-emissivity glass curtain wall and clerestory windows around the perimeter illuminates much of the general office space. Incandescent-halogen uplighting provides a gentle 35 to 40 footcandles of illumination to supplement the daylight.

According to Bebart, incandescent-halogen fixtures were chosen over more-economical low-pressure sodium technology because, during demonstrations, the low-pressure sodium fixtures created an undesirable pinkish shade.

The lighting system uses only 1.04 watts per square foot.

One major challenge involved heating and cooling the second floor, says David Eitel, vice president of V.A. Smith. "Because there's no ductwork in the ceiling, at certain points air must be distributed up to 50 feet across the room," adds Eitel. The solution was an HVAC system more commonly found in an airport than an office: a constant-volume, variable-temperature, forced-air system.

The rooftop unit provides 12 air changes per hour-compared with four to six per hour common in most offices-which Eitel says is required to prevent water condensation on the exposed steel members. "Because the roof and steel members are fully exposed and have no vapor barrier or insulation," adds Eitel, "the surface temperature of the steel must be maintained above the dew point to avoid condensation."

Other green measures

Environmental-friendly materials, including nontoxic paints and recyclable ceiling tiles, were specified. Moreover, the carpet will be reclaimed by the manufacturer after its useful life for recycling or reconditioning.

The material selection process, however, also took into consideration cost, performance and appearance. Bebart says this provided a more practical approach to selecting green materials. "Not all materials are recyclable," he says. "For instance, we chose vinyl tile flooring in the copy rooms versus linoleum, because linoleum is five times more expensive and, frankly, we didn't like the appearance as much."

Scrap materials were sorted for recycling. Tristate Recycling Services of Northlake, Ill., collected metal, wood, paper, concrete and masonry for $350 per load. In all, 75 percent of waste material was recycled.

The result is a lesson in green building design and sustainability-a healthy, open workplace that lives among the trees.

Some employees liken the view of the trees to "having different artwork on the walls daily."

         
 

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