New Frontiers in Office Space

11/2006 By Tristan Roberts

Click here to view a slide show; Photo © Mike Sinclair

KEY PARAMETERS Jefferson City, Missouri, Missouri River watershed GROSS SIZE FOOTAGE : 120,000ft2 / 19,300 m2 COMPLETED: March 2005 COST: $18.1 million ANNUAL ENERGY USE (based on bills): 68 kBtu/ft2 (775 MJ/m2) ANNUAL CARBON FOOTPRINT (PREDICTED):20 lbs. CO2/ft2 (97 kg CO2/m2) PROGRAM:Offices, conference rooms, food service, atrium. DATA click to View larger Heating/Cooling Temp./Dew Point Sky Conditions Lewis & C lark TEAM OWNER:State of Missouri, Missouri Department of Natural Resources ARCHITECT & INTERIOR DESIGN: BNIM Architects COMMISSIONING AGENT: Sys-Tek ENGINEER Structural Engineering (structural); Smith & Boucher (mechanical); FSC (electrical); SK Design Group (civil) LANDSCAPE: Conservation Design Forum ENVIRONMENTAL BUILDING DAYLIGHT DESIGN/ENERGY STRATEGIES: ENSAR Group (now RMI/ENSAR Built Environment) LIGHTING: Clanton Engineering GENERAL CONTRACTOR: Professional Contractors and Engineers MECHANICAL SYSTEMS DESIGN: Rumsey Engineers cost ESTIMATOR: Construction Cost Systems SOURCES BYCYCLE RACKS: BRP Enterprises WA2-11-SM unit masonry: Prairie Stone Northfield Block STRUCTURALGLUED LAMINATED TIMBER: Mississippi Laminators exterior architectural woodwork: Trex (e ntry sun shade) LINOLEUM: Armstrong Colorette building insulation: Bonded Logic cotton fiber; International Cellulose spray applied SIDING: James Hardie Siding Hardiplank lap siding interior doors: VT Industries Curries quartersawn ash ALUMINUM ENTRANCE AND WINDOWS: Kawneer tubular skylights: Huvco GLAZING: Low E Insulating Glass, Viracon VE Ceramic-coated spandrel Insulating glass, Viracon Heat Mirror lighting controls: Lutron PV: Uni-Solar PVL Field Applied Laminate louvers and vents: Greenheck RAISED FLOOR: Haworth TecCrete XL fabric lightshelves: Rosebrand polyester/lycra

Even before the outset of design and construction of the Lewis and Clark State Office Building, the mission was clear: create a green office building and certify it to the highest level of LEED without overtaxing the credulity of the taxpayers in the “Show-Me States.” The modest budget, $18.1 million, was provided by the Missouri state legislature before the tenant, the Department of Natural Resources, had even put the sustainability goals on the table. But it was the writing on the wall that crystallized the building’s environmental goals.

“When we were interviewing for the project, we spent one afternoon in the state Capitol building reading inscriptions that are carved into a particular wall about the natural resources of the state,” says architect Steve McDowell, FAIA, of BNIM Architects. “We read about the minerals, animals, plants, rivers—all the natural things that were important to the character and nature of Missouri,” he says. “We thought we were already committed to the green agenda, but looking back at what was important to the founders and early citizens of the state influenced how deeply we held those values through the project.” That commitment was nurtured from the beginning of the process, when BNIM organized a design charrette that involved m­­ore than 100 people, representing all parties involved in the project.

Not far from where Meriwether Lewis and William Clark embarked on their exploration of the American West in 1804, the building is a stone’s throw from the Missouri River. The 120,000-square-foot structure extends about 350 feet along the east-west axis, and only 70 feet from north to south, a ratio that was calculated to reduce energy costs and maximize interior daylight.

Choosing the site was integral to the project. “We started with some sites that we felt were unsuitable, because they were set out in the suburbs, for example, so we challenged our client to look for a more urban site,” says Kimberly Hickson, AIA, one of the project managers for BNIM. The state came back with 17 sites, including the one that was eventually chosen.

Constructed on the 144-acre site of the former Jefferson City Correctional Facility, eight blocks from downtown, the office building is one piece of an ambitious mixed-use urban redevelopment project. It took the place of a former women’s prison, with bricks from the prison being used for a number of interior surfaces.

In a landscape design based on xeriscape principles, indigenous grasses, shrubs, and trees have thrived despite a dry first year. Vegetated bioswales and topography that encourages stormwater infiltration help meet a goal of keeping runoff out of the municipal stormwater system. The landscaping is not without maintenance needs, but they are considerably less than in a conventional landscape. “We pull weeds from it. It has been mowed once,” says Dan Walker, director of the general services program for the Department of Natural Resources, who represented the tenant throughout design and construction. Nature trails around the site and reaching toward the river are planned.

Green features extend from the outside into the building. A 50,000-gallon cistern collects rainwater from the roof, which is filtered and used in flushing toilets. The system conserved 405,000 gallons in its first 13 months. One hundred and sixty-eight photovoltaic panels produce 21.5 kilowatts of power, or 2.5 percent of the building’s needs. Thanks in large part to a well-planned daylighting system and the careful design of the heating and cooling system, the building is predicted to use less than half of the energy of a comparable ASHRAE base model.

The narrow aspect ratio of the building, solar orientation, and both interior and exterior light shelves help daylight penetrate deep into the office space. Employees enjoy access to views and daylight at workstations that are located around the perimeter. Enclosed rooms are generally situated at the core. Many of the windows are operable, providing natural ventilation. Although the daylighting scheme went through computer modeling by ENSAR Group, which has since merged with the Rocky Mountain Institute’s Green Development Services, during part of the winter a gap between the interior canvas light shelves and the glazing causes glare in some workstations. A miscommunication with the fabricator led to the mistake, which wasn’t present in models, and the problem is being fixed in time for next winter.

The building design also keeps employees active. Amenities such as changing rooms and showers were created largely for those who bike to work, but also encourage occupants to exercise. A number of people jog during their lunch breaks, according to Walker, and some walk downtown for meetings. Nearly everyone uses the prominent and attractive stairs in the central atrium.

Although all of these features reduce operating costs and increase occupant satisfaction, the building team was still concerned that its construction budget would lead to compromises. At one point, the state balked at buying the low-emissivity glass specified by the architect, so the firm ran an energy model with a lower-cost alternative. “We found that we could spend the money on glass or we could spend it on a bigger mechanical system,” Hickson says, noting that the mechanical system would add energy and maintenance costs over the long run. The glass stayed. The engineer performed a similar analysis on the building’s aspect ratio when the client wanted a boxier profile; again, the analysis confirmed the efficiency of the design.

The project used an integrated design process, but owing to the requirements of competitive bidding, a contractor wasn’t involved early on. “I guess we were all somewhat nervous at the bid opening,” says Hickson. “We didn’t really know where it would fall.” The team received a low bid from a trusted contractor, although one without experience in green building. The contractor worked hard to meet the sustainability goals and helped the team gain LEED points in construction waste recycling and recycled content of materials, at a time when the project was on the edge of achieving Platinum. “There was a lesson there,” says Laura Lesniewski, AIA, BNIM’s project manager during the construction phase. “If you have someone who’s interested in learning, he doesn’t need to have prior experience.”

Despite the project’s impressive achievement in the LEED rating system, the team gave up points along the way. It procured lumber from Missouri’s only certified sustainable forest for the atrium, but for the roof structure, which uses exposed glued laminated beams, the team couldn’t locate a product with certified content. It also hoped to earn a point for reducing the urban heat island effect with reflective roofing, but the emissivity level of the roof left them a fraction short of the requirement.

The team went to extra lengths to achieve some points, such as using furniture that meets indoor air quality (IAQ) standards. State agencies are required to purchase furniture manufactured through prison inmate vocational programs, so the team brought its sustainability agenda to the prisons, working to help them achieve Greenguard Indoor Air Quality listing for its furniture.

“The building performs well and our occupants are extremely happy from the perspective of IAQ, lighting, and heating and cooling,” says Walker. Several occupants have reported better health in this building after having sinus problems in previous buildings, he adds. Walker has also noted reduced absenteeism, an observation the department plans to investigate by examining employment records.

By all accounts, the success of the project was based on the commitment to sustainability by the key members of the team. Built on budget, the building is also meeting financial performance expectations over the long term. “We did life-cycle costing on every aspect of the building, and so far things are on schedule,” says Walker.