When the opportunity to develop a new airport arose, the City of Austin, Texas chose to integrate sustainability into the entire airport development process. PB served as program manager for the new airport, which was constructed on the former Bergstrom Air Force Base site. Our staff blended with Austin Aviation Department staff to create the New Airport Project Team (NAPT), which managed planning, design, construction, and commissioning.

Figure 1: Austin-Bergstrom International Airport

The now completed Austin-Bergstrom International Airport (Figure 1) is a model for airport sustainable development. Energy efficiency, improved air and water quality, water conservation, reuse and recycling and efficient use of resources are examples of the comprehensive approach to sustainability taken on this project. From careful site planning and design to reduced noise impacts and new public schools, we helped to construct an airport that operates efficiently and effectively, minimizes the depletion of natural resources and yields significant social benefits to the community.

Sensitive Site Planning

The approach to airport sustainability began with careful site planning. Our intent was to maximize site attributes and develop an overall plan that would allow the airport to operate efficiently. Key features are:

• The orientation of the terminal building reduced the amount of wall and window glazing required on the eastern and western portions of the terminal. In addition, shading devices were installed on the southern portion of the terminal to minimize heat gain.
• An efficient airfield layout was designed to minimize aircraft taxi distances, resulting in lower fuel use and reduced air emissions. Alternative fuels are not practical for commercial aircraft, so reducing engine burn time is the primary mitigation strategy to reduce aircraft emissions.
• NAPT worked closely with the local transit agency to ensure accessibility by current available mass transit (buses) and future proposed mass transit (light rail) systems.

Reuse and Recycling

Much of the existing military base infrastructure was reused or recycled through the following initiatives:

• An on-site salvage yard was established to assist contractors, who displayed and sold doors, cabinets, windows, electrical and plumbing fixtures, air conditioning and heating equip¬ment and other salvageable items.
• Electrical primary wiring was salvaged and sold for scrap.
• Building demolition waste was segregated by type of materials to allow recycling of steel and copper building components.
• More than 250,000 tons of existing military aircraft parking pavement was broken up, crushed, and then re-used underneath new pavements and utilities, providing a stable base for airport facilities construction, saving more than $2 million in construction costs and diverting a significant waste stream from local landfills.
• Existing runway, taxiway, and apron pavements were rehabilitated and reused.
• An existing aircraft hanger scheduled for demolition was disassembled and reused by the contractor.
• On-site fencing was reused for permanent and temporary access controls.
• Topsoil, the rich organic layer in which most plant roots grow, was removed from areas where excavation was required and stockpiled for later reuse.
• Excess soil from excavations was reused for embankments rather than hauled off site.
• More than 40 trees were relocated on the site, making way for new airport facility construction.
• An airport waste recycling program was implemented for reuse of paint solvents, recycling of waste oil from vehicle engines and oil filters, and reclamation of jet fuel from the airport fueling facility.
• Dual trash chutes were installed in the terminal. At each location there is one for recyclable waste and one for all other waste. The trash compactor area also is set up with dual compactors for the separation of waste materials to encourage recycling.

Sustainable Raw Materials Use

Figure 2: Locally-Sourced Granite Used in Terminal Construction

Building materials were selected for durability, longevity and ease of maintenance. Specific sustainability features of the terminal building included the following:

• The primary framing system, which includes beams, columns, shapes and plates, was constructed from 100 percent recycled materials.
• Concrete reinforcing steel used in construction contained 95 percent recycled materials, and the steel studs used in the wall infrastructure contained 65 percent to 75 percent recycled materials.
• Concrete used in the terminal construction contained 10 percent to 15 percent flyash (a power plant waste byproduct), and the runway, taxiways, and apron concrete mixes contained 20 percent flyash. Approximately 16,000 tons of flyash were used on the project.
• Granite flooring and walls, and terrazzo flooring were used throughout (Figure 2) because these materials are durable, can withstand the rigors of public traffic, and are non-absorptive—a quality that improves indoor air quality. Granite was obtained from local sources to reduce environmental impacts associated with transportation.
• Finishing paints emit low levels of volatile organic compounds (VOCs), enhancing indoor air quality.
• Recycled products were used throughout, such as gypsum paperboard facing that contained 100 percent recycled materials.
• Toilet partitions in the restrooms contain a high density polyethylene (HDPE) recycled plastic content.
• Carpeting installed throughout had a manufacturer guarantee that all returned carpet will be recycled into other products.
• Wood products used in the overall construction of the airport were supplied from controlled growth forests.
• Roofing insulation was manufactured without the use of chlorofluorocarbons (CFCs). In addition, the roofing is comprised of light colored cap sheets that reflect heat—an important feature given the hot Texas sun.

Energy Efficiency

Figure 3: Thermal Storage Reduces Peak Electrical Loading

The established goal for energy efficiency in the passenger terminal was to exceed the Lighting and Thermal Envelope standards of the energy code¹ by more than 15 percent and 10 percent respectively. Some of the systems/ techniques that enabled the city to achieve these goals included the following

• The terminal building central heating and cooling systems are among the most reliable and energy efficient available. A unique thermal storage facility for air conditioning system chilled water (Figure 3) allows the airport to operate the chillers during the off-peak night hours and then use the cool water during the day. It provides a peak electrical load reduction in excess of 1400 kW, equating to a 48 percent reduction in peak demand.
• Thermally efficient glass that restricts heat flow but allows natural light to pass was used throughout the terminal. Ceramic frit also was applied to certain glass lights located in carefully designated areas to specifically reduce glare and heat gain while retaining visual acuity.
• Efficient building insulation was used throughout the terminal.
• Photovoltaic arrays were installed in two areas of the airport to generate electricity as well as provide shade for waiting vehicles (Figure 4).

Figure 4: Photovoltaic Arrays Provide Electricity and Shade from the Texas Sun

Figure 5: Capture and Sedimentation Ponds Discharge Clean Storm Water

Water Quality and Conservation

Every opportunity was taken to improve the quality of water leaving the airport property, resulting in nearly 180 000 m2 (2 million square feet) of water quality improvements being constructed, including sedimentation/filtration basins, temporary holding ponds and other runoff controls. Water quality ponds were placed at strategic points across the site to filter storm water runoff from aircraft ramps and vehicular parking areas (Figure 5). Some of the more innovative water quality and water conservation initiatives included the following:

• Sophisticated recovery equipment and separators were incorporated into the aircraft fuel storage facility to recover fuel leakage associated with normal fueling operations.
• All aircraft fueling and de-icing areas have fuel spill collection and containment systems.
• Contaminated runoff is captured and disposed of rather than being discharged, primarily via sanitary sewer and treatment plants.
• All fixtures in public toilets use automatic flow control valves.
• Landscaping was limited to native plants with extensive use of xeriscaping principles (which foster the use '”unthirsty” native plants and drought tolerant exotics for waste-efficient landscaping). Prairie grass and low growing native grasses were used to reduce mowing and other field maintenance requirements, and the irrigation system limits overspray on non-porous paved areas.
• Reclaimed wastewater is used for irrigation of the airport golf course. In addition, the airport can expand reclaimed water use (either stormwater or treated effluent) to the irrigation system supply as adequate quantities become available.

Air Quality Initiatives

The city and NAPT developed and implemented the following landside and airside initiatives to achieve excellent indoor air quality and reduce emissions from airport sources.

• Restricting infiltration of contaminated outdoor air through the use of vestibules and air doors.
• Purifying ventilated air through the use of high efficiency air filters that absorb odors, VOCs and emissions.
• Utilizing interior finish materials and air delivery ducts that are resistant to microbiological growth, and treating all air conditioning equipment and duct insulation to resist microbiological infestation and growth.
• Exhausting areas prone to having contaminated air directly to the outside.
• Providing automatic ventilation control on the apron through the use of a carbon monoxide sensor system.
• Using low emission fuels, heating and cooling equipment.

Some of the more creative features that help to minimize air emissions and thereby reduce impacts on regional air quality include the following:

• Aircraft parked at the gate use building-supplied electric power and air conditioning, thereby eliminating the need to operate on-board auxiliary power units.
• The latest instrument landing system technology allows aircraft operations in the poorest of weather conditions, so aircraft spend less time idling while waiting for clearer weather or holding while waiting to land.
• Alternative fuels such as compressed natural gas and electricity are available for use in ground service equipment that services airplanes and other airport vehicles.
• The Aviation Department uses alternative fuel vehicles with low emissions for airport operations and encourages airport tenants to do the same.

New Airport Delivers Social Benefits

Some of the more noteworthy social benefits provided during development of the airport included:

• Military Housing Relocation. More than 700 single-family and duplex military houses were relocated and made available to low-income families using low-interest loans. Duplex houses were cut in half, yielding two smaller houses. This measure saved the city approximately $1 million in demolition costs.
• Salvaged Chapel Elements. The existing military chapel was located in a corridor needed for airport access roads. During demolition the City worked with its contractor to locate a small church that needed the beautiful wood beams and bell. The contractor worked carefully around the beams preventing damage while exposing them for removal.
• Reduced Noise Impacts. When the new airport opened, aircraft activity noise impacts were significantly reduced. The number of residents who lived in an airport noise impact area was reduced from 30,000 (around the former Robert Mueller Municipal Airport) to approximately 1,500.
• Job Training. NAPT hosted an on-airport training program through which workers were trained and certified for construction jobs. Many graduates transitioned to construction jobs on the new airport.
• Small and Minority Contractor Assistance. NAPT established a small contractor assistance team that helped small and minority firms with bidding and winning airport construction contracts.
• Golf Course Recycled. The existing Air Force golf course was modified to accommodate the new airfield configuration and was added to the City’s inventory of public golf courses, providing a local recreational benefit.
• New Public Schools. Four schools adjacent to the airport and previously impacted by military aircraft noise were purchased by the airport. Upon receipt of $45 million in funding, the local school district constructed four new state-of-the-art schools, providing a direct benefit to local students.
• Passport to Aviation: NAPT created “Passport to Aviation” an educational outreach to local public school students that used airport construction to teach environmental principles, math and science. Students visited the new airport monthly over a seven-year period for a brief lesson followed by a field visit to see the principles put into action.

Conclusion

Austin-Bergstrom International Airport is truly is a model for airport sustainability. The measures implemented provided immediate and long-term environmental, financial and social benefits for Austin citizens and all travelers who use the airport.