This is the third article detailing the Northwest Service Center, a new vehicle maintenance center for the City of Dallas. Situated on a 17 acre Brownfield site, construction began April 2005, and was completed in Spring 2006. Originally slated for LEED Silver status, the project has been awarded GOLD certification. 

The City of Dallas Equipment and Building Services Department recently captured LEED Gold Certification for the Northwest Service Center (NWSC), a 92,271 square foot maintenance complex.  The complex sits on a 17 acre former Brownfield site in Northwest Dallas, and features 55,972 square feet of occupied space. The site, which is mostly industrial, consists of two buildings housing the Streets, Sanitation, and Equipment and Building Services departments. There are also covered storage areas housing supplies and equipment as well as fueling islands, and car/truck washing bays for these groups. 

Mitchell Enterprises of Sherman, Texas and VAI Architects Incorporated of Dallas, Texas completed the project under a design-build contract with the Mitchell/VAI team (MEL/VAI). Other design team members included Huitt-Zollars Inc. (engineering), Parsons-Brinckerhoff (equipment design), Air Engineering and Testing, Inc (Commissioning Agent) and HDR, Inc. (LEED consulting). The subcontractors involved played a key role in assuring the project was built according to the strict guidelines set by the team.

The USGBC LEED v2.1 Green Building Rating System was used. The LEED Green Building Rating System is a standard that defines and provides strategies for achieving a high performance green building. This set of guidelines allows for the design team to select several credits the project will set out to achieve.  The LEED Green Building Rating System is a whole design approach that must be implemented from conceptual design through training all building personnel and maintenance staff. Anyone can design and build a high performance green building, but if the occupants don’t know how to properly use the facility then nothing will perform to its design or full potential. City of Dallas equipment and building services director Jack Ireland says “We’re very proud of the designation the Northwest Service Center has received because it is another example of Dallas’ commitment to environmental stewardship and leadership.”

The City of Dallas currently requires a minimum of Silver Certification for any City owned, bond-funded projects over 10,000 square feet. The NWSC was submitted to the USGBC for Gold Certification and successfully achieved 43 of the 69 possible points. During the design stages the entire MEL/VAI team worked closely to set these goals while both the on site superintendent and LEED Accredited Professional (AP) worked closely with all on site personnel to ensure these goals were successful. Mitchell/VAI assigned Rachael Green, a full-time LEED AP, to orchestrate construction phase data collection and coordination on-site.  Green says, “I believe the integration of all project stakeholders throughout the design-build process was key to making this project an overwhelming success.” 

Removal and recycling of concrete and asphalt paving took place before construction started. Since the project was on a brownfield site, remediation was required after demolition of the used car lot, which previously occupied the space. The demolition of the used car lot, asphalt and concrete all incorporated recycling activities. Several of the items were also donated to other organizations for reuse. A company located a few miles away used the excavated soils to cover an existing parking lot, thereby creating a new greenspace with native landscaping. Existing light poles were also donated to a local church that in turn converted them into flag poles used at a new Veterans Memorial site. Over 100 abandoned used tires were sent to a local recycling facility. “There were a few times during this process where we were all starting to question the capabilities of recycling some of these components. It was difficult to find recyclers who would accept a lot of the demolition materials. But we did it and were successful,” said Green.  During the construction and demolition process a total of 99.18% of the collected materials were recycled.

During construction, an extensive Indoor Air Quality (IAQ) program was implemented. This program included no smoking, eating and/or drinking inside the buildings. All materials were properly stored and protected from weather and cross contamination. During the installation of mechanical equipment all ductwork was cleaned and protected to allow no particulates to enter into the units prior to initial start up. In addition to the IAQ program, the specifications included the use of no to low VOC (Volatile Organic Compounds) materials. These materials included items such caulking, sealants, adhesives, glues, paints, sealers, primers, carpet systems, furniture, fire sealants and caulking, insulation, gypsum wall boards, etc. Some of the other components incorporated to maintain healthy IAQ included vacuuming insides of all wall tracks prior to the last side of sheetrock being installed. All composite wood components were free of added urea formaldehyde as well as no formaldehydes used in other building materials. The buildings were maintained clean and free from water, dust and other harmful chemicals and components. Indoor air quality testing was performed prior to building occupancy with passing results. There were no harmful chemicals, particulates, formaldehyde or VOC’s in the buildings.  After the building occupants moved in, one was heard saying her allergies had not bothered her since being in the new building. This is proof that incorporating LEED® and sustainable guidelines improves the health, safety and well being for building occupants. CFC reduction was implemented with the use of non-ozone depleting products in all HVAC&R equipment as well as installing carbon dioxide, carbon monoxide and propane monitoring equipment for occupant safety.

Site features include landscape design and highly reflective roofing and paving materials to help reduce local heat island effects. The landscaping includes no permanent irrigation, native plants, grasses and trees with little to no maintenance required, and implements an onsite organic maintenance plan. With a fleet of over 270 city vehicles, the Northwest Service Center uses four Vortechnics stormwater separators to remove 80% of the average total suspended solids and 40% of the average annual phosphorous contained in stormwater.  The site is located along public transportation access to both DART bus lines and a future DART light rail line. Bicycle storage along with carpool and vanpool parking is available to all employees and visitors.

The vehicle wash facility utilizes a wastewater reclamation system and enjoys a 68.40% reduction in water use. Other water savings devices include water free urinals and low flow fixtures in all toilets, showers, sinks, and kitchen areas. A combination of the water-wise landscaping, wastewater reclamation and water saving devices helps to achieve a large reduction for potable water demands.

Over 56% of the materials used (by value) included recycled content either post consumer and/or pre-consumer. The complex contains over 10,000 square yards of recycled content concrete and 646 tons of recycled steel. The fabric on the systems furniture is even decomposable. Over 80% of the site facilities structures can be safely recycled at the end of its life span. A large majority of the products can be sent back to the original manufacturing facility where the materials will then be reprocessed and reused as new materials. Over 80% of the project’s materials were manufactured within 500 miles of the project site and out of the 80%, half were harvested within 500 miles of the project site.

Mechanical components assisted in energy reductions by the use of energy recovery wheels, high performance mechanical units and intense commissioning and training activities resulting in an estimated energy reduction of 20%. While 20% does not appear to be a large amount, take into account only 16, 000 sq. ft is cooled space while the shop areas are not air conditioned. All office areas that are air conditioned spaces utilize high performance chillers operating using an HCFC-free refrigerant and state of the art VAV technologies. Filters for all units include the use of Minimum Efficiency Reporting Value (MERV) filters of 13. The exhaust air energy is used for preheating the makeup air. The rotary wheels recover energy from the exhaust air and return it to the supply air. Mechanical equipment not only makes up the 20% reduction, but the window glazing, building orientation, insulation values, roofing materials, proper sealing of the building and lighting components such as occupant sensors also contribute. Measurement and verification tools are also utilized throughout the site. A complex monitoring systems provides real time monitoring for all mechanical and electrical components. This system offers the city the advanced technological option of monitoring usage, alarms and events either on site or from remote locations.

Public art sculptures provided by David B. Hickman include sustainable elements not only in the design, but also in the naming of each piece. The two art pieces are both sustainable and functional. Both “FLOW” and “Vortex” are constructed of carbon steel elements manufactured from recycled materials and the limestone seating accompanying the pieces was quarried in the Texas Hill Country and offers low maintenance and durability.

Rachael Green, LEED AP, is a licensed interior designer with 13 years of design and construction experience, the last five of which have involved sustainable design. In addition to her role as LEED Services Director at Komatsu Architecture, she also serves on the Board as a Director for the USGBC North Texas Chapter. Rachael has also provided local training on the LEED rating system. For additional information regarding this article, please contact Rachael Green at rgreen@usgbcnorthtexas.org. All comments are the sole responsibility of the writer.