Weather conditions of the past several years have punctuated the importance of water conservation in the southeastern U.S. This precious resource is a major focus of the Gwinnett Environmental and Heritage Center, located just northeast of Atlanta. A joint effort of the Gwinnett County Board of Commissioners, Gwinnett Public School System, and the University of Georgia, Athens, the center features exhibits that define the role of the region’s water historically, culturally, and environmentally. First profiled by eco-structure in May/June 2007, the building was designed by Atlanta-based Lord, Aeck and Sargent and employs an innovative vegetated roof, as well as a number of water and energy efficiency techniques to practice what the center’s programs preach.
When it opened in fall 2006, the center was aiming for LEED Silver certification from the U.S. Green Building Council. Ultimately, it earned more points than expected and garnered LEED Gold. “We were fortunate to pick up a few additional credits during construction,” explains John Starr, principal in charge of the project for Lord, Aeck and Sargent. “The contractor did a great job with things like waste management, recycled content, and some of the other credits we had indicated as possibilities in our design analysis.”
The center has exceeded expectations, not only in terms of LEED points, but also in building performance and general popularity with the local community. It hosts numerous school programs and community events, as well as weddings and other private parties. “The facility manager told us they’ve had a lot more programs after hours than they had anticipated,” says Meg Needle, project manager with Lord, Aeck and Sargent. “The flexibility of the energy management system has been valuable in allowing the facility manager to tweak and optimize systems.”
Making the most of the building’s energy and water management systems has been a continuous effort. Natural light floods the facility during daytime hours and a series of sensors and automated lighting controls help maintain an optimum illumination level at all times. This requires a great deal of observation and adaptation. “The building’s operations manager has worked through a number of initial challenges with the system,” Starr points out. “It has required determining the best positions for the motorized glare controlling shade system, optimizing the automatic light dimming system that is controlled by daylight sensors, and sorting through a number of other factors. For example, they found that after swapping out the original fluorescent lamps for another manufacturer’s lamps, they got better performance from both the dimmable fluorescent lamps and ballasts.”
Nonpotable water from a nearby water treatment plant is used to create a central water feature on the site, passing between the two buildings. In addition, the feature acts as a heat sink as the water is circulated through the building for cooling. Early in the design phase, there was debate among project members about how to deal with algae in the cascading pool. One idea was to create a natural ecosystem in the pool, but the county was hesitant to deal with the cleaning challenges presented by hosting live plants and fish. Ultrasonic devices were explored, but ultimately the decision was made to treat the water using an eco-friendly additive.
A 40,000-square-foot, sloped vegetated roof tops the facility. Innovative when built because of its sheer size and 18-degree slope, the roof has undergone a few changes but continues to perform well. A cellular confinement system stabilizes the growing medium to the roof. That approach continues to work as planned and there hasn’t been any significant slipping of the soil. However, a major drought in 2007 created some problems in establishing the plantings on the roof. The roof had to be replanted and a graywater irrigation system was installed. Still, as the facility continues to evolve, it has proved to be an inspiration to its visitors and a point of pride for its designers.
To read eco-structure’s original feature on the Gwinnett Environmental and Heritage Center (May/June 2007), see page 20 of the digital issue at eco-structure.com/052007 .
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We still think of it as one of our best green buildings. Though we have a couple of LEED Platinum buildings now, we were able to do some experimental things in this building, such as the water cooling system and the large green roof,” says John Starr of Lord, Aeck & Sargent. “We learned a lot of lessons we’re continuing to integrate into other projects.” Among the knowledge gained thus far:
It is very important to have a tight specification about the types, spacing, and quantity of plants used on the vegetated roof. To allow regular maintenance of a sloped vegetated roof, consider tie-offs and other safety features in the design stage so you don’t have to add them later on. In this case, Gwinnett County has looked into a permanent tie-off point and harness setup to provide a higher degree of safety for its maintenance staff.
When installing porous pavement and creating a plan for stormwater management, make sure that when the charging bed gets full there is a system or outlet to handle overflow water. If the natural soil surrounding the system has slow permeability, as is the case with Georgia’s red clay, the water has to go somewhere else.
Build in a longer commissioning and owner-training period to properly deal with optimizing shade and daylight controls. Be cognizant that controls for different systems such as daylight sensors, energy management systems, and motorized shade controls may not be compatible, making them hard to integrate.
It was discovered that the automatic dimming controls were creating issues with lamps and ballasts burning out prematurely. By instituting a full-strength burn period of 24 to 48 hours for each new lamp before installation, this problem has been mitigated.