The new U.S. Environmental Protection Agency (EPA) Region 8 Headquarters in Denver, Colorado allowed EPA to emphasize environmental responsibility through the building's design, construction, and operations.
EPA required that the new building achieve a LEED Silver certification and an Energy Star rating, and follow EPA's comprehensive procurement guidelines. The building surpassed expectations and achieved LEED Gold.
Located on a busy urban site close to public transportation, the building was designed to maximize daylighting and provide shelter from the prevailing winds for a rooftop garden on the south side of the building. A well-insulated building envelope, high-performance glazing, and energy-efficient lighting and mechanical systems all contribute to a 39% energy savings over ASHRAE 90.1-2004 standards.
Low-flow fixtures, dual-flush toilets, and waterless urinals contribute to 40% water savings. Products made from rapidly renewable materials, including wheatboard, corn cloth, rice hulls, and bamboo, were used throughout the building. Many materials contained high percentages of recycled content, and many were locally sourced.
The project team approached the energy requirements for the building from a whole-building design perspective, incorporating mechanical systems design with daylighting strategies, building envelope design, and other aspects of the design. A 10-kilowatt, grid-tied photovoltaic array provides electricity for the building. In addition, EPA agreed to purchase all of its power from renewable sources, and no ozone-depleting hydrochlorofluorocarbons (HCFCs) or halons were used in equipment.
The main energy-efficient features of the project include:
- a building envelope featuring insulation levels of R-19 in the walls and R-31 in the roof;
- high-performance glazing;
- an ethylene propylene diene monomor (EPDM) rubber roofing membrane with a high-emissivity acrylic coating;
- a building form that creates a double "L" shape with an atrium in the middle, allowing significant daylight penetration;
- external sunshades made from a 20-inch perforated metal shade with an 11-inch fin;
- internal lightshelves on the south faÃƒÂ§ade and a set of nine parabolic, Teflon-coated sails in the atrium that reflect daylight into the building;
- energy-efficient lighting and reduced lighting power density;
- occupancy sensors and photosensors;
- underfloor air distribution and demand-controlled ventilation coupled with carbon-dioxide monitoring;
- parking-area ventilation controlled by carbon-monoxide sensors; and
- variable-speed drives for the chiller and pumps, high-efficiency motors, and air-side and water-side economizers.
In addition to the energy saving measures incorporated into the design and construction of the building, the property management company instituted daytime janitorial service, in which janitors work side-by-side with office professionals during the regular workday. While most buildings continue to consume energy throughout the night, this management practice allows the EPA Headquarters lights and HVAC system to be automatically turned off for 10 - 12 hours each day, resulting in a substantial reduction in energy expenses and light pollution. In 2007, daytime cleaning reduced energy costs by an additional 28 percent, saving nearly $250,000 ($.80/square foot).
Excerpted and adapted from full case studies available from the DOE Federal Energy Management Program and the NIBS Whole Building Design Guide.
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