|The CMUD consolidates the operations of four separate laboratories and several Environmental Management divisions for Charlotte/Mecklenburg, N.C. All photos: Tom Kessler|
The Environmental Services Facility for Charlotte Mecklenburg (N.C.) Utilities (CMUD) consolidates the operations of four separate laboratories and several Environmental Management divisions. This new building includes public meeting areas for community outreach and interagency training sessions. The Laboratory Services Division tests water quality for drinking water and wastewater, while the Environmental Management Division oversees the operations of CMUD’s wastewater treatment plants. The facility was designed to meet state-of-the-art laboratory criteria but also to demonstrate CMUD’s commitment to environmental stewardship.
The project began modestly in 2001 as an interior renovation of a laboratory space that was housed within the existing main office building. After a series of early programming meetings between CMUD, Gantt Huberman Architects, Charlotte, and its laboratory consultant, Steven Rosenstein Associates (now merged into the New York firm Perkins Eastman), the project evolved into a new facility. The client concluded that renovating the existing building would not fully address CMUD’s current and future needs.
CMUD’s primary requirement was to consolidate into one facility the Environmental Management and Laboratory Services Divisions that were located in various locations across the Charlotte Mecklenburg metropolitan area. The consolidation would eliminate expenditures associated with operating and maintaining multiple facilities. In addition, there were ongoing maintenance expenses associated with building deficiencies in the outdated laboratories.
The building is located in a densely wooded area that is on the southern edge of the Irwin Creek Wastewater Treatment Plant. The building occupies the site’s highest elevation to take advantage of views of the woods. The “L” shaped building has three distinct parts. The primary part, the main entrance and central spine, connects the other sections and organizes the plan; it is sheathed in white corrugated metal. The second part, the environmental management areas and community rooms, is sheathed in red brick. The third part, the laboratories and service area, is sheathed in split-faced concrete masonry. (See this month’s digital edition for a floorplan: http://www.rdmag.com/General/Laboratory-Design-News-Archive/)
Because the site slopes gently south to north, and minimum site disturbance was an important sustainable design goal, the mechanical and electrical rooms were tucked under the main floor, reducing the building’s footprint.
A colorful custom-designed glass canopy suspended under a steel structure covers the main entrance. The glass was designed by Seattle artist Pam B. Bayette, and depicts tiny creatures found in water and wastewater. The central spine begins at the glass canopy, continues through the building, and terminates at the outdoor staff patio. The spine is punctuated by small impromptu seating and informal conference areas with views to the wooded areas beyond. The spine features a linoleum floor pattern that is rich with colorful serpentine forms and swirls symbolizing running water and sunlight.
Daylighting into all habitable areas is provided with north-facing roof monitors, horizontal exterior sunshades, and interior lightshelves. The offices and laboratories are bright and pleasant and offer views to the woods beyond.
Laboratory organizational ideas
Meetings were held with the Laboratory Service staff from all four existing laboratories and Gantt Huberman to establish goals and objectives. During those meetings, it became clear that operating separate facilities was producing fragmented activities and some redundant analysis. In addition, the existing laboratories were overcrowded, and functions were not zoned properly.
The new laboratory layouts consolidated redundant analysis and added space to correct deficiencies as well as to accommodate future growth. The laboratories were zoned so that seating and office areas could be accessed without having to walk through active laboratory analysis areas. Fume hoods were located in areas where there was minimal circulation. In addition to providing efficient and environmentally controlled laboratory analysis areas, dedicated support areas were provided, including equipment rooms, cold rooms and a field support and loading dock area for sample receiving that maintains chain of custody protocols.
Finally, the facility was designed so that there was sufficient flexibility to support current test procedures as well as future needs.
The building integrates sustainable practices as a fundamental part of its design. It has received LEED Gold certification from the USGBC, and was the first building constructed by the city to receive LEED certification. In pursuing this sustainable goal, CMUD has demonstrated its commitment to environmental stewardship and leadership in sustainability.
Choosing sustainable strategies for lab buildings requires more finesse than most building types. The integrity and functionality of the labs cannot be compromised at any cost. This leaves the design team with fewer fiable options from the sustainable design palette. The selected strategies must be carefully implemented during the design and construction to ensure the desired results.
Since CMUD provides fresh drinking water for the surrounding communities, the conservation of water resources was a high priority. Water-use reduction was accomplished through the implementation of several strategies, including an ozone water treatment system for the cooling towers that reduced the need for fresh water in the HVAC system. Low-flow plumbing fixtures were also specified, and the landscaping was selected to require no irrigation system.
Another strategy utilized was the proper integration of daylighting into the lab spaces. The recent trend toward more open labs lends itself better to daylit spaces, but the natural light has to be controlled to avoid glare and heat gain that can affect lab functions. During design, the lab spaces were virtually and physically modeled with a daylighting laboratory (the Energy Performance Laboratory Center for Architectural Technology, at the Univ. of North Carolina-Charlotte) so that the exterior shading devices and interior light shelves could be designed for maximum effect within the labs. These passive strategies were combined with integrated lighting controls to provide proper light levels as well as helping to save energy.
Maintaining good indoor air quality can be especially challenging in labs. The high demands for fresh outside air combined with exacting thermal comfort requirements can create high demands on the mechanical systems. To maintain good air quality and “right size” an efficient HVAC system, the facility’s design included VAV fume hoods, carbon dioxide sensors, and low-VOC materials and finishes.
Other sustainable materials incorporated include linoleum made from rapidly renewable flaxseed oil, concrete with a higher volume of reclaimed fly ash, carpet with recycled content, and FSC-certified wood doors and laboratory casework.
The site and parking around the building were also carefully planned to retain as many existing trees as possible, to provide a wooded buffer and minimize construction grading. Rain water is managed on-site through the use of rain gardens planted with native plants to help reduce the water volume and remove pollutants before leaving the site. As an added bonus, the naturally maintained landscape surrounding the building provides calming and scenic views for the occupants.
The air distribution system serving this facility was divided into two sub-systems reflecting the nature of the space and usage of the facility. The Environment Management block was provided with a mechanical system served from a variable volume 100% outdoor air unit and a variable volume 100% recirculating air handling unit. An indoor air quality (IAQ) terminal box for each thermal zone introduced the quantity of outdoor air required to satisfy the CO2 sensor for that zone. The Laboratory Services block was provided with a variable volume – terminal heating air distribution system served from a 100% outdoor air handling unit. Each laboratory module was then controlled by way of temperature, space pressurization and fume hood flow controls. The highest need requirement accordingly modulated the supply air delivered to the zone.
All laboratory exhaust was removed from the laboratory modules by way of a manifolded laboratory fume hood exhaust system ducted to N+1 redundant tri-flow exhaust fans on the roof.
The mechanical design provided not only a high standard of comfort and associated energy savings but also an overall low noise level (both inside and outside of the building).
Mechanical systems that need to accommodate very high percentages of outdoor air building requirements also need to respond to very low system thermal demands to very high thermal demands. Project load analysis led to the use of both modular boilers and modular chillers to accommodate these wide ranges of operation as well as to provide N+1 equipment standby capacity.
Since the building’s opening in 2008, the Laboratory Service and Environmental Management operations have improved significantly. Additionally, CMUD has been recognized in the community for its continued commitment to environmental stewardship for building the first LEED Gold certified building for the city of Charlotte.
Barbara Lane, AIA, and Alan Hunter, AIA, LEED AP, are associate and project architect, respectively, with Gantt Huberman Architects. The Charlotte, N.C.-based firm offers architecture, planning and interior design services (www.gantthuberman.com), with a strong commitment to sustainable design. Other firms involved in this project included McCracken & Lopez, Charlotte (mechanical engineer); Browning Engineers Inc., Charlotte (structural engineer); Stewart Engineering Inc., Charlotte (civil engineer); Engineering Economics Inc., Raleigh, N.C. (commissioning authority); and Beam Construction Co., Cherryville, N.C. (contractor).