Alfred A. Arraj U.S. Courthouse
Location
Denver, CO
USA
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Certifications & Awards
- Green Building Challenge in 2005 achievement level Total Weighted Building Score
Project Team
- Owner: General Services Administration
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Summary
A showcase for sustainable design and a milestone project for the General Services Administration (GSA), this 318,850-square-foot facility is a tangible demonstration of GSA's commitment to environmental stewardship, and it is among the first U.S. Courthouses to meet new Justice Department security standards.
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Overview
- Location: Denver, CO
- Building type(s): Public order & safety
- New construction
- 319,000 sq. feet (29,600 sq. meters)
- Project scope: 11-story building
- Urban setting
- Completed November 2002
Rating: Green Building Challenge --Level: Total Weighted Building Score: 2.0
A showcase for sustainable design and a milestone project for the General Services Administration (GSA), this 318,850-square-foot facility is a tangible demonstration of GSA's commitment to environmental stewardship, and it is among the first U.S. Courthouses to meet new Justice Department security standards.
Recalling a traditional town square courthouse, the two-story pavilion, which contains the public entrance and special-proceedings courtroom, acts as the frontispiece to the entire composition. The 10-story tower houses five floors of district courts, two floors of magistrate courts, offices for the U.S. marshal and clerk of the court, a jury assembly area, a special-proceedings courtroom, and a GSA office.
Environmental Aspects
The courthouse incorporates the latest proven technologies for environmentally sensitive design, construction, and operation. Photovoltaics, daylighting, and underfloor displacement ventilation systems contribute to a 40% reduction in projected energy usage compared to a conventional courthouse. Exterior and interior finishes feature durable natural and renewable materials, including brick, stone, wood, and cork. All interior finish materials were selected based on their impact on the environment and on occupants. Low-impact landscaping minimizes water use and reduces the project's contribution to the urban heat-island effect. Low-flow lavatory faucets and water closets are used throughout.
Owner & Occupancy
Owned and occupied by General Services Administration, Federal government
- Typically occupied by 381 person
Building Programs
| Indoor Spaces: | Public assembly (30%), Office (23%), Circulation (15%), Structured parking (13%), Conference (8%), Mechanical systems (5%), Detention (4%), Lobby/reception (2%), Other |
| Outdoor Spaces: | Interpretive landscape, Garden—decorative, Drives/roadway, Patio/hardscape |
Keywords
Integrated team, Design charrette, Training, Green framework, Simulation, Green specifications, Commissioning, Operations and maintenance, Transportation benefits, Indigenous vegetation, Efficient irrigation, Drought-tolerant landscaping, Massing and orientation, Insulation levels, Glazing, Airtightness, Passive solar, HVAC, Lighting control and daylight harvesting, Efficient lighting, On-site renewable electricity, Adaptable design, Durability, Benign materials, Recycled materials, Local materials, Certified wood, Occupant recycling, Connection to outdoors, Daylighting, Ventilation effectiveness, Thermal comfort, Noise control, Low-emitting materials
Team & Process
In 1996, GSA sponsored a 20-member advisory committee to evaluate sustainable design strategies, including systems, materials, and delivery techniques, for courthouses.
GSA's goal was to "use the latest available proven technologies for environmentally sensitive design, construction, and operation. It should set a standard and be a model of sustainable design." Another goal central to sustainable concepts was to create a building that would remain effective for 100 years.
The client and design team evaluated every item in the study, developed a cost/payback model, and incorporated as many features as possible into the design and construction process.
A baseline energy model was established simulating a minimally code-compliant building meeting ASHRAE 90.1-1999 criteria. Design options were compared to baseline to evaluate energy savings, and a proposed option that would achieve an energy performance of more than 40% better than baseline was selected.
The design team evaluated the energy consumption of courthouse options utilizing DOE-2.1E software.
The team used detailed computer modeling and Lumen Micro v.7.5 software to evaluate design options including electric and daylighting systems under a range of time of day and sky conditions.
The team used CFD modeling for the displacement ventilation system.
A pilot version of the U.S. Green Building Council's LEED(r) guidelines was part of the building design, construction contract, and overall philosophy of the project.
The design team also included:
- Contractor
- Environmental building consultant
- IEQ consultant
- Plumbing engineer
- Lighting designer
- Interior designer
- Programming
Finance & Cost
In planning for the courthouse, GSA made a conscious decision to challenge its conventional thinking about building economics. This included developing a project budget that allowed for additional investment in sustainable design opportunities.
GSA's careful approach to determining the proper level of investment included commissioning a construction cost consultant to analyze the projected costs and viability of various green-design strategies.
As the design progressed, the design team evaluated all expenditures for upgrades to the design that would improve the environmental performance of the building relative to the sustainable-design budget. This ensured that decisions could be justified in terms of lifecycle economics, enabling the owner to recoup its initial investment.
The design team compared initial costs with lifecycle paybacks for features such as a daylight dimming system, displacement ventilation, energy-efficient HVAC systems, raised-access flooring, and high-performance curtainwall glazing.
- Procurement process: Design-bid-build
Cost data in U.S. dollars as of date of completion.
- Total project cost (land excluded): $86,000,000
In terms of both conventional and environmental performance, the investment in sustainable design resulted in a better building overall. While not every green design feature provides a payback, in aggregate, the green-design measures produce lifecycle cost savings that will pay back the initial investment within 25 years of operation.
Land Use & Community
The courthouse adds a fourth block to Denver's downtown Federal District. Its form consists of a two-story pavilion and a 10-story tower with a penthouse level. The two building components relate in height to the other structures within the Federal District. The public plaza, which faces the existing courthouses, has a southeast exposure that receives sun from early in the morning through the lunch hour. This provides a pleasant atmosphere and assists in the morning clearing of ice and snow.
The exterior materials also relate to the historic buildings within the Federal District. The vertical expression increases the visual height of the building and is a modern interpretation of the vertical forms of existing historic courthouses.
The site is within 1/8 mile of a light-rail line and next to several bus routes. Onsite parking is located in the lower levels of the tower and limited, for security reasons, to judges and the Marshal Service. More than 20% of the staff uses public transportation or bicycles to work. Showers are available for bicycle commuters, walkers, and runners. The Court provides passes to any employee utilizing the bus or light-rail system.
Property Evaluation
Assess property for integration with local community and regional transportation corridors
Responsible Planning
Ensure that development fits within a responsible local and regional planning framework
Properties with Excessive Impacts
- Avoid contributing to sprawl
Support for Appropriate Transportation
Design development to have pedestrian emphasis rather than automobile emphasis
Provide showers and changing areas for bicycle and pedestrian commuters
- Provide storage area for bicycles
- Provide access to public transportation
- Provide incentives for non-automobile commuting options
Property Selection Opportunities
- Look for opportunities for infill development
- Select already-developed sites for new development
Site Description
As a federal courthouse, the site concept must balance security, sustainability, and openness. The courthouse footprint is compact to increase onsite landscaped areas and maximize vehicle standoff distance. A southeast-facing plaza provides public open space.
In developing the site, the design team considered four essential concepts integral to expressing the Western landscape: the land-surface patterning, the contrast between mountain and plain, the textures and colors of indigenous materials, and the precious nature of water in the region.
The landscape functions as a self-contained ecosystem that does not require much care or irrigation. Plant materials were selected for their ability to thrive in the local micro-climate and urban environment. This includes indigenous and xeriscape plants such as drought-tolerant buffalo grass.
The site's hardscape areas use a variety of materials in sand setting beds instead of concrete. This increases the site's water absorption capacity and reduces stormwater runoff. Interlocking concrete pavers, flagstone, and sandstone are installed in sand setting beds. Low-traffic perimeter areas use grass-block paving and crushed-stone surfaces that provide even greater permeability and hold up well under freeze-thaw conditions.
- Lot size: 2.45 acres
- Building footprint: 37,400 sq ft (3,470 sq meters)
- Previously developed land
Water Conservation and Use
To minimize water loss to evaporation, a drip-irrigation system provides water for ground cover, perennials, and trees during establishment and as a supplement during drought conditions. Low-flow lavatory faucets and water closets are used throughout the building to minimize indoor water use.
Development Impacts
- Minimize building footprint
- Limit parking area
Runoff Reduction
- Avoid contiguous impermeable surfaces
Demand for Irrigation
- Select plants for drought tolerance
Irrigation Systems
- Use water-efficient irrigation fixtures
Siting Analysis
Hire a landscape architect to help with siting of buildings and infrastructure
- Assess regional climatic conditions
Investigate microclimate (specific variations from regional climatic conditions)
Site Planning
- Provide for solar access
Energy
Building energy efficiency is achieved through a combination of strategies that first seeks to reduce end-use energy loads, then to satisfy reduced loads through highly efficient mechanical and electrical systems and renewable energy sources.
An articulated curtainwall design, together with high-performance, low-emissivity glazing, controls solar heat gain, heat loss, and visible light transmission while minimizing glare and HVAC controls.
Daylight meets the ambient lighting needs of the clerk and marshal offices, judge's chambers, main public corridors, and spectator seating in the courtrooms. Indirect pendant electric lighting with T-5 fluorescent lamps, compact fluorescent lamps, and metal-halide downlights supplements the daylighting throughout the courthouse as required. Occupancy sensors, photocell controls, and electronic dimming ballasts save energy in daylit areas. Furniture-mounted task lighting provides additional light as needed by users.
A digital control system regulates the HVAC and lighting systems, turning them off in unoccupied spaces. Heating and cooling requirements are served by adjusting supply-air volumes according to the occupancy of various zones. Variable-speed drives on all fans and pumps reduce energy consumption during part-load operation. Evaporative cooling, suitable for use in the Colorado climate, reduces the cooling-related energy consumption, especially when compared with the use of conventional chillers.
Electricity produced by 126 photovoltaic modules on the building's roof produce 11.5 KWdc rated at standard test conditions and 8.1 KWac peak power measured as installed. offsets approximately 1/3 of 1% of the building's annual electricity consumption, with the capability of shaving up to 1% off the peak electrical demand. The photovoltaic cells are sandwiched between translucent glass panels, providing partial shading. The system is grid-tied, and excess energy is fed back to the utility grid.
Materials & Resources
Local materials, such as native stone, were incorporated into the courthouse exterior. The building has a steel frame with recycled content. The majority of the flooring materials, including sandstone, cork, and recycled plastics, are from recycled or native sources. (This is the first known application of cork on a raised-access floor.) Most ceiling materials were also manufactured from recycled materials. The Comprehensive Procurement Guidelines established by the U.S. Environmental Protection Agency guided the acquisition of recycled-content products.
All interior finish materials were carefully selected based on their impact on the environment and on the building's occupants. Factors such as embodied energy, indoor air quality, and resource depletion were considered for all materials. All paints and adhesives are low in volatile organic compounds (VOCs). Maple paneling, sourced from certified forests, was applied to lobby and courtroom walls.
Recycling bins are located on each floor for the collection of paper and aluminum cans.
The general contractor and subcontractors were required to recycle metals, woods, paper, and other materials as part of the construction contract.
- Access Flooring Systems
- Cork Flooring Tiles
- Recycled-Rubber Athletic Flooring
The building was designed for a 100-year life. The exterior and public interior areas utilize durable materials that should last the life of the building. Interior office areas and courtrooms utilize a raised-access floor system for wire management, enabling easy reconfiguration of communication, data, HVAC, and lighting systems.
The courthouse is planned for a future addition to facilitate forecasted growth. The footprint for the expansion was considered in siting the building. The elevator tower and corridor systems were designed to connect avoiding duplication and inefficiencies.
Job Site Recycling
- Require a waste management plan from the contractor
Recycling by Occupants
Specify recycling receptacles that are accessible to the occupants
Design for Adaptablity
Use an access floor to facilitate reconfiguring of spaces and cabling systems
Toxic Upstream or Downstream Burdens
- Use natural cork flooring
Pre-Consumer Recycled Materials
- Choose frame and sash materials made from recycled materials
Materials and Wildlife Habitat
Use wood products from independently certified, well-managed forests for finish carpentry
Transportation of Materials
Prefer materials that are sourced and manufactured within the local area
Indoor Environment
The courthouse has a bright, airy indoor environment designed to increase the comfort of building occupants. The improved building envelope together with the displacement ventilation system and perimeter heating eliminates cold drafts. The building complies with ASHRAE Standard 62-1989, the industry standard for indoor air quality. Outside air controls maintain minimum design ventilation rates. Direct outside air accounts for 75 percent of cooling. Air intakes are located high in the building to avoid the introduction of vehicle exhaust, the reintroduction of building exhaust air, and contamination from mechanical equipment.
A separation between view glass and daylighting glass maximizes daylight harvesting to reduce electric lighting while providing occupants with a strong connection to the outdoors. Approximately 75% of the occupied building spaces have access to daylighting. The high-rise portion incorporates perimeter lightshelves between view and daylight glazing that bounce daylight onto the ceiling plane and adjacent architectural surfaces, minimizing contrast ratios between interior surfaces and elements viewed through the glazing. The two-story pavilion has clerestory windows that light the entry rotunda and backlight the ceiling in the special-proceedings courtroom.
Finish materials and construction specifications were analyzed for their chemical composition to avoid products and materials with potentially harmful chemical emissions. All paints, adhesives, and finishes are water-based and low-VOC.
Entry of Pollutants
- Locate outdoor air intakes away from pollution sources
Thermal Comfort
- Use glazing with a low Solar Heat Gain Coefficient
Visual Comfort and The Building Envelope
Use large exterior windows and high ceilings to increase daylighting
- Use skylights and/or clerestories for daylighting
- Incorporate light shelves on the south facade
Choose interior and exterior glazing to maximize daylight transmission
Visual Comfort and Interior Design
Install large interior windows to allow for the transmission of daylight
Acoustics and Occupant Noise
Minimize sound transmission between rooms with appropriate detailing and material densities
Reduction of Indoor Pollutants
- Use only very low or no-VOC paints
Awards
Colorado Renewable Energy Society in 2000; Category/title: Institutional Building Category
GSA Environmental Award in 2001; Category/title: Model Facility Demonstrations, Non-Hazardous Category
Ratings
Green Building Challenge in 2005; achievement level: Total Weighted Building Score: 2.0
Lessons Learned
Strict adherence to the pilot version of the U.S. Green Building Council's LEED(r) guidelines was part of the building design, construction contract, and overall philosophy of the project.
Investigations to reduce project cost determined that the underfloor displacement ventilation system cost less than traditional variable-air-volume systems.
One challenge was the difficulty finding recyclers for all construction waste generated on the job in this location. Unfortunately, the construction recycling goal was not met. There was no monetary incentive to recycle in this region.
Learn More
Magazines
"Innovators & Award Winners"
Publication: Engineering News-Record (December 23, 2002) http://enr.construction.com/resources/special/archives/innovators_2002.asp#
GSA
Web sites
Alfred A. Arraj U.S. Courthouse, Denver, CO General Services Administration
A brief case study describing the basic features of the building.Green Building Challenge 2005 General Services Administration
A short description of the project, with links to its submission to the Green Building Challenge 2005.
Others
Report: Solar is Saving Energy for the Alfred A. Arraj U.S. Courthouse
This four-page report, produced by the National Renewable Energy Laboratory, profiles the Arraj Courthouse's photovoltaic system. (PDF 949 KB) Download Acrobat Reader
