The Missouri Department of Natural Resources takes its role as the state's environmental steward seriously, so when it commissioned the Lewis & Clark State Office Building to serve as its base of operations, the agency charged the Building Team with creating the state's greenest building, one that would boldly advance Missouri's green building efforts.
Threatening to derail the agency's lofty ambitions was a relatively modest budget of $18.6 million (not including land costs). The state legislature had approved the building's funding well before the project's sustainability goals were set; as a result, the project architect, Kansas City, Mo.-based BNIM Architects, had to push sustainable design limits and meet all the building's practical programmatic criteria while saddled with a budget set for traditional office construction. The resulting 120,000-sf facility was completed for $154/sf and received a LEED Platinum rating.
"This building demonstrates that designing an environmentally-sensitive and energy-efficient building doesn't have to add cost to the project," says Steve McDowell, BNIM design principal.
The Lewis & Clark Building sits high atop a limestone bluff in Jefferson City overlooking the Missouri River valley, not far from where Meriwether Lewis and William Clark began their "Corps of Discovery" in 1804. An ideal setting? Hardly. The land had been neglected for years through irresponsible development and had suffered destructive runoff that eroded its natural slope toward the river bank, at the edge of the city's core. On top of that, a shuttered women's prison still occupied the property.
The team's ecologists, Conservation Design Forum of Elmhurst, Ill., created a land reclamation plan that focused on carefully dismantling the prison complex (the bricks were salvaged for use as interior finishes in the new building), removing site waste, and developing a zero-runoff landscape by reintroducing native species and restoring bioswales for maximum water absorption and minimum maintenance.
Pavement was kept to a minimum: one small parking lot, room for only 55 cars. Instead, the agency asks employees to use existing, nearby parking lots (which are connected to the office building by shuttle bus service); it also encourages carpooling, public transportation, and bicycling. There is secure storage for 22 bikes and changing rooms and showers.
The four-story office building has a slim footprint that treads lightly over the land. The building extends east and west from a central atrium and is only 70 feet wide north to south. Its narrow width makes the most efficient use of standard 30-foot-wide structural bays; the building is two bays wide, with five-foot overhangs on both the north and south sides.
Most of the building's windows (many of which are operable) are on the north and south sides to maximize daylighting, while window openings on the east and west sides are minimal to reduce glare and solar heat gains. No interior work space is more than 38 feet from a window because communal spaces and enclosed rooms are located at the building's core, with work zones located around the perimeter.
The building's cast-in-place concrete construction—with 25% fly ash content—incorporates a ribbed façade for vertical sun shading and deep horizontal sun shades. Located just below the tops of the windows, the sun shades block excessive sunlight and protect against heat gain but also reflect sunlight back into the building near the ceiling level. Aided by interior light shelves constructed of white canvas, the reflected light is bounced further into the building to penetrate the deepest interior spaces. Additional interior lighting is provided by direct and indirect interior lighting systems with fully dimmable ballasts that automatically adjust light levels based on occupancy and natural light levels.
Energy models indicate that the building is 59% more efficient than a comparable baseline building, and while effective use of natural light is a significant energy saver, there are several other strategies at work. For instance, the air handlers are staged throughout the facility in order to reduce ducting requirements, thus reducing fan-power requirements by 60%; total system pressure drop is one-third that of a typical system.
In addition, a dedicated outside air system uses supply air at a higher temperature than that of a standard system; in conjunction with the air handlers, this system allows the use of medium-temperature chilled water—55 degrees F rather than 42 degrees F—for more efficient cooling. The building's domestic hot water supply is aided by 168 photovoltaic panels, which also contribute 2.5% of the facility's energy.
The building's roof is engineered for rainwater collection (which also helps correct the site's runoff problems) by sloping inward toward an internal gutter that drains to a 50,000-gallon cistern located underneath the facility. As much as 95% of the building's graywater needs are handled by the cistern.
The Building Team sweated even the smallest green details. The atrium's wood flooring is harvested from Missouri's only certified sustainable forest. Carpet tiles are made with a high percentage of recycled plastic material, such as milk bottles, and building materials—from paints to adhesives—are all low in volatile organic compounds.
Missouri requires state agencies to purchase furniture manufactured through its prison inmate vocational program, so the Building Team worked with the manufacturing representatives to incorporate sustainable materials and practices into their methods. The result is perhaps the only prison furniture in the world that is Greenguard certified.
Construction waste practices also went super green. The Building Team located area businesses to recycle steel, aluminum, glass, drywall, wood, cardboard, and plastics, diverting as much as 88.6% of construction waste (11,134.9 cubic yards) from landfills.
The exploration of sustainable building practices in the Lewis & Clark State Office Building shows that high-performance buildings and "normal" construction budgets need not be mutually exclusive. It's fitting that the Missouri River Valley continues to serve as a place of discovery more than two centuries after Lewis & Clark's famed journey.