Striking Gold in Texas
A new Armed Forces Reserve Center achieves LEED Gold at no additional cost to the government.
By David Nordin and Jim Brunson, RLA, ASLA, CPE, LEED AP BD+C, M.SAME
The Armed Forces Reserve Center in San Marcos, Texas, is a model of sustainability and energy efficiency. PHOTOS COURTESY SATTERFIELD & PONTIKES CONSTRUCTION INC.
A new Armed Forces Reserve Center training facility in San Marcos, Texas, is a prime example of turning Department of Defense (DOD) sustainability criteria into installation reality. Built to replace and consolidate undersized and outdated training facilities for the U.S. Army Reserve and Texas National Guard, the three-building complex—recommended by the Base Realignment and Closure Commission—was constructed using a total precast concrete system and designed to achieve LEED certification.
New DOD guidelines require the sustainable and effective development and operation of military installations and individual buildings therein. Moreover, Executive Order 13514 requires the federal government to implement high-performance sustainable building design, construction, operation, management and maintenance.
The San Marcos Reserve Center is meeting this mandate on many levels. In fact, although the $24 million design-build project was originally planned to meet LEED Silver requirements, the project team took on an even greater challenge of pursuing additional credits and qualifying for LEED Gold. Earning these additional credits would come at no additional cost to the government.
The project’s energy-efficient sustainable building goals included indoor air quality, construction waste reduction, water and energy efficiency, and use of regional building materials. Design-built by Satterfield & Pontikes Construction (S&P) in association with architectural firm Atkins, the complex includes a 62,648-ft² assembly hall and training center; a 29,700-ft² heated storage building; and a 25,717-ft² maintenance shop. The 19-acre site also includes parking for 172 privately owned vehicles and 13,700-yd² for military equipment.
S&P constructed all three buildings using a total precast concrete building system designed by Atkins to meet LEED Silver criteria. Total precast concrete construction was selected because of its ability to meet an accelerated work schedule and its inherent sustainability, flexibility, durability and low maintenance. It is renewable, recyclable, locally manufactured and provides excellent thermal mass that can be supplemented to create more energy efficiency.
During the design phase, the project team worked closely with the U.S. Army Corps of Engineers (USACE) to adhere to the many sustainable features required by DOD. The team’s considerable experience in designing and constructing LEED-certified buildings facilitated collaboration in incorporating additional components that helped elevate the project from the required LEED Silver to the desired LEED Gold.
Building information modeling (BIM) and energy modeling helped construct this highly energy-efficient complex. An on-site virtual studio used BIM extensively to produce 3D models of the entire project. In particular, BIM determined that the building could be constructed more quickly through the use of precast concrete walls. Whereas typical precast might be 8-in thick, the energy model specified a 10-in thickness for the walls. The desired energy efficiency could be achieved with 4-in of concrete, 4-in of insulation in the center and an additional 2-in of concrete.
BIM models, plans and specifications (with LEED considerations incorporated) were supplied to the precast manufacturer. This enabled the precise manufacturing, delivery and erection of the concrete panels to meet the fast-track schedule.
To help reduce water consumption, low-flow plumbing fixtures were installed inside the complex’s three buildings. The design provided for dual-flush water closets, pint urinals and low-flow lavatories, showers and kitchen sinks. Indoor water use will be reduced by 54 percent compared to conventional buildings.
The facilities also feature water-efficient landscaping. No permanent landscape irrigation system was required, so there is no impact on the city’s fresh water supply.
A major contributor to the project’s success is the precast concrete design and construction. The 10-in thick pre-cast walls are sustainable, low-maintenance, very durable and long-lasting.
The Energy Policy Act of 2005 (EPAct) established numerous energy management goals for federal facilities. USACE had specific standards that needed to be met for the design and construction. One of those was to reduce energy usage by at least 30 percent. State-of-the-art heating and ventilation equipment is installed in the San Marcos Reserve Center. The project team used sophisticated computers to monitor the HVAC system, ensuring that it runs at peak efficiency. Advanced modeling techniques made certain that air is distributed evenly. The 100 percentlevel energy model indicates a 34.3 percent reduction in energy consumption under EPAct and 30.6 percent energy cost savings for LEED.
Included in the energy requirement is enhanced refrigerant management. Selected HVAC refrigerants must minimize or eliminate the emission of compounds that contribute to ozone depletion and global warming. The mechanical design includes the McQuay Air-cooled Chiller, which uses R-134A refrigerant and meets the credit requirements. In addition, no fire suppression systems were installed that contain ozone-depleting substances.
Material selection and resource management are essential to sustainable construction. By managing construction waste, using products containing recycled materials and procuring materials near the construction site, the team ensured sustainability was achieved. Nearly 97 percent of construction waste on the San Marcos project was recycled and diverted from landfills, including concrete, brick, wood, metal, cardboard, paper and glass. More than 36 percent of all construction materials contained recycled content.
LEED credits also were earned for using building materials or products that were extracted, harvested, recovered, or manufactured within 500-mi of the project site. This significantly lowered transportation costs and CO2 emissions. Regional materials comprise more than 45 percent of the new center. In addition, more than 86 percent of the wood used is certified in accordance with the Forest Stewardship Council’s Principles and Criteria for wood building components.
Site design is the first step in making sure a building can be sustainable. At San Marcos, the team used modeling techniques to determine the optimal position of the building. The approach included efficient land use for habitat protection, storm water design and reduction of heat island effect. The project restored a minimum of 50 percent of the site area (excluding the building footprint) with native or adapted vegetation. And the paving materials have a Solar Reflectance Index of at least 29, reducing heat build-up.
Additional functionality included maintaining the predevelopment stormwater discharge level of the undeveloped site. Stormwater runoff is controlled and conveyed to on-site detention ponds for protection of the downstream channels.
The standing seam metal roof, another sustainable feature of the complex, is a highly reflective red on steep-slope areas and white on low-slope areas, and further reduces the heat island effect.
Air quality also was taken into consideration during design. Emissions of indoor pollutants are reduced by the use of low-emitting volatile organic compound materials for adhesives, sealants, paints, coatings, carpeting and composite wood, which do not have dangerous off-gases. LEED credits were earned for outdoor air delivery monitoring, in which ventilation systems must maintain specified ventilation requirements, as well as the construction management plan, in which materials (such as ventilation duct work) are received, stored and installed so they are protected and not contaminated by dust or other materials that could adversely affect occupants.
INNOVATION & APPLICATION
The Armed Forces Reserve Center in San Marcos exemplifies how sustainable design and construction can balance environmental concerns with the health and comfort of end-users while improving building performance.
In addition, the owner will realize significant cost savings in operation, management and maintenance throughout the lifetime of the buildings. It is a successful project that will continue to deliver beneficial returns.