Text description provided by the architects. The new Environmental Protection Agency (EPA), Region 8 Headquarters building sits on an urban brownfield that formerly housed a U.S. Postal Annex. This LEED Gold rated design is the result of a challenging design process that sought to integrate a contemporary, high-performance, secure, and environmentally sensitive building into one of Denver’s most important historic and civic districts. A key program goal was to assimilate the new facility into the urban fabric in a way that strengthens and enhances the quality of the historic neighborhood in which it is located, while establishing the building as a landmark in its own right. As a Federal building, the structure also had to meet strict Department of Homeland Security requirements, resulting in a Level 4 facility.
Project description and images after the break.
The building used a wide variety of sustainable materials including, corn-based fabric and wheatboard, recycled glass tile, recycled-content carpets, recycled steel, cork floors, bamboo wall panels and doors made with rice hull cores. In sum, more than 89% of the wood-based materials and products used in the building are certified in accordance with the Forest Stewardship Council’s Principles and Criteria.
Additionally, fly-ash was used in the concrete portions of the building and regional materials – those manufactured, produced or harvested within 500 miles of the building – were used for more than 50% of the structure’s manufactured materials. Construction waste was also reduced, with as much as 80% of the total waste generated was recycled or diverted from local landfills.
Scarcity of water in Colorado makes it a precious resource. With the help of experts from the EPA, the design team demonstrated to local authorities the effectiveness of “ecoroofs” as a means of both removing pollutants from stormwater and reducing the rate and quantity of stormwater runoff. The result is the first “green” roof in Denver used to manage stormwater.
Populated with native, drought-tolerant plant species that minimize irrigation requirements, the 20,000 square foot vegetated roof covers three terrace levels and treats stormwater while reducing the urban heat-island effect of the building.
Variations of a glazed curtain-wall system were designed for the different facades – the sunward (southeat and southwest) façades were designed with horizontal exterior sunshades and a system of internal light shelves designed to cut glare and solar gain. The windward façades (northeast/northwest) have a series of exterior vertical shades to cut glare from low-angle summer sun while simultaneously harvesting diffused light from the clear North Sky. The net result, 75% of workstations receive significant daylight.
In addition to serving as a great “room”, the EPA building’s atrium was also developed to enhance the building’s office spaces by providing light from both sides of the office floor plates instead of from the building’s perimeter alone. However, due to the atrium’s depth and aspect ratio, directing light into the atrium proved to be a unique design challenge-a challenge that was compounded by budget constraints and a tight building schedule.
Seeking an alternative to conventional, and generally more expensive reflective devices like mirrors, and needing a solution that could be easily and economically installed, the ZGF design team began to study how light could be directed down into the atrium most effectively. A large-scale physical model was used on a heliodon (an artificial sun) to examine the possibilities.
The ultimate design solution needed to do two jobs simultaneously; reflect light down into the atrium and shield the office occupants on the atrium’s upper floors from the glare of direct sun, the reflector system would need to hang below the glass skylight instead of stand above it. The design solution required a parabolic shape (in section profile) in order redirect light hitting it from various angles into a fairly uniform downward direction. The reflectors needed to be deeper at their lower, outer corners due to the atrium geometry, resulting in a distinct “butterfly” shape being applied to the reflectors.