Case Study: Far Southeast Austin
EMS Station

Project Goals
The goal of this project was to meet its design objectives and achieve a LEED Silver rating. The project more than succeeded on both counts, and earned the first LEED Gold rating in Texas. Part of the reason for this unprecedented success was that this project had an experienced LEED consultant on board: Gail Vittori of the Center for Maximum Potential Building Systems (CMPBS), who strategized conservatively to allow for mistakes to be made and points to drop out. Fortunately, the team did not make many mistakes - hence the LEED Gold rating.

The insulated concrete wall system contains a high amount of recycled material, and is produced close to Austin, both of which helped score more LEED credits. The wall presented a bit of a learning curve to the builder, who utilized Gridwall's representatives to help troubleshoot problems during construction. Since Gridwall is typically used only in residential construction, this is one of the larger (and taller) buildings ever to employ it. In the end, the builder gained a marketable skill working with an innovative material. EMS personnel who use the building may not notice the low energy bills, but they rave about the sound insulating qualities of this product. Even sirens from the neighboring fire station are muffled.

The building was designed with minimal glazing towards the South and West as well as generous shaded porches, in order to reduce heat gain during Austin's long cooling season. Even the rainwater collection cistern was sited carefully to shade the entryway and cool the main air intake for the truck bay. The truck bay itself was not required by the City to be air-conditioned, so the designers took care to shape it for passive ventilation, creating a stack-effect open clerestory to pull hot air up and out.

Other energy-saving strategies designed by the mechanical engineer, Greg Canter of Tom Green and Co., included total enthalpy wheel heat recovery, and a decoupled outdoor air supply with 3 separate heating/cooling zones. Air systems included CO2 monitoring. The truck bay included an exhaust capturing system for the emergency vehicles.

Project Description
This 5,300 sq ft stand-alone station for City of Austin Emergency Medical Services (EMS) earned Texas' first LEED Gold rating! The building was designed to perform as a 24/7 response facility, with an active truck bay and communication area, while also serving as a "home away from home" for EMS personnel.

The architect for this project, Betty Trent AIA, had 25 years of experience in earth-friendly design. She assembled an enthusiastic team of designers and engineers. According to Wes Goodwin, the Commissioning Agent, "The architect did an excellent job of conducting key coordination meetings that not only included all members of the design team, but also included key persons representing the Owner who would be responsible for operating and maintaining the facility." Real collaboration between all the interested parties was an important part of this project's success The client, the City of Austin, also provided a very conscientious representative to oversee the process and champion the City's goal of achieving a LEED rating.

In order to reduce energy usage in the always occupied building, the team got creative and implemented a series of complementary energy strategies. Perhaps most visible of these is the wall system made of insulating leave-in place formwork and poured concrete. The 10-inch thick, R-27 super-insulating Gridwall system, is notable for its light weight and ease of construction. This system, coupled with an insulated roof and a thick foundation slab, creates a substantial thermal mass which helps regulate temperature swings.

Project Features

Sustainable Sites (9 of 14 points):

• Prerequisite: erosion & sedimentation control
• Meets LEED requirements for site selection
• Alternative transportation: public transportation access w/in 1/4 mile of site
• Alternative transportation: bicycle storage and changing rooms
• Alternative transportation: one alternative fuel refueling station on site
• Alternative transportation: parking capacity meets but does not exceed minimum zoning requirements and carpooling spaces are provided
• Stormwater management: no net increase in rate or quantity of run-off from site
• Stormwater management: 95% total suspended solids (TSS) and total phosphorous (TP) removal (City of Austin standards are more stringent than those required by LEED)
• Landscape & exterior design to reduce heat islands, non roof: impervious surfaces paved with highly reflective materials
• Light pollution reduction: site illumination is 1.5 footcandles and all light is maintained within the project boundaries

Water Efficiency (4 of 5 points):

• Water efficient landscaping, water use reduced by 50%: low water plants
• Water efficient landscaping, no potable use or no irrigation: rainwater collection system installed for irrigation
• Water use reduced by 30%: low flow toilets, showers, and water using appliances (2 points)

Energy & Atmosphere (7 of 17 points):

• Prerequisite: fundamental building systems commissioning
• Prerequisite: minimum energy performance
• Prerequisite: CFC reduction in HVAC & R equipment
• Optimize energy performance, 30% new/20% existing: increased wall and roof insulation, high performance windows, high efficiency lighting, high efficiency heating and cooling, high efficiency water heating, and exhaust heat recovery wheel (4 points)
• Optimize energy performance, 40% new/30% existing: building performs 41% better than ASHRAE 90.1 - 1999. (2 points)
• Ozone depletion: no CFCs or HCFCs

Materials & Resources (4 of 13 points):

• Prerequisite: storage & collection of recyclables
• Recycled content, specify 10%: 16% of building materials content uses recycled materials (2 points)
• Local/regional materials, 20% manufactured locally: 31% manufactured locally
• Of 20% above, 50% harvested locally: 55% of above manufactured within 500 miles

Indoor Environmental Quality (12 of 15 points):

• Prerequisite: minimum IAQ performance
• Prerequisite: environmental tobacco smoke control
• Carbon Dioxide monitoring
• Low emitting materials: adhesives and sealants, paints, carpet, composite wood (4 points)
• Indoor chemical and pollutant source control: measures installed as required
• Controllability of systems, perimeter: operable windows and lighting controls for perimeter spaces
• Controllability of systems, non-perimeter: air flow, temperature, and lighting controls for non-perimeter spaces
• Thermal comfort: complies with ASHRAE 55-1992
• Thermal comfort, permanent monitoring system: temperature and humidity monitoring system
• Daylight and views, daylight 75% of spaces: minimum 2% daylighting in 96% of space
• Daylight and views, views for 90% of spaces: building complies with requirement

Innovation & Design Process (3 of 5 points):

• Chemical-free termite barrier: Termi-mesh barrier system
• Exemplary performance of MRc5 (Materials & Resources credit 5): 16% of total building materials content uses recycled materials
• LEED accredited professional: Gail Vittori, Center for Maximum Potential Building Systems

Testing/General Results:

Energy Efficiency:
Goodwin Engineering modeled and analyzed several core mechanical systems; minor architectural building components such as window glass properties, shading, wall and roof R-values; as well as several of the creative design elements such as the solar chimney and thermal mass storage foundation. They returned energy consumption for each run of the model to the design team for cost and constructability analysis as well as point-return analysis by the LEED coordinator. In the end, a 41% energy reduction was achieved, worth six LEED points.

Water Conservation:
Because of Austin's strict stormwater management standards, the project easily surpassed LEED's requirements for stormwater retention and treatment. The site was designed with a small water quality pond and native plantings that require minimal irrigation during the long dry spells between rains. Any irrigation that is needed to beautify the site comes from rainwater collected off roofs and stored in large cisterns. The EMS crews were at first concerned about the technical issues of the water storage tanks and the maintenance required to operate them. Another crew concern was the selection of water saving residential appliances. In the end, the water collecting system and the ultra low-flow dishwasher have only demanded a bit of patience from the crew.

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