Troxel Hall is golden

Green roof on Troxel Hall

Nearly three-fourths of the Troxel Hall roof is planted with vegetation, as seen from Bessey Hall. Photo by Bob Elbert.

Troxel Hall, the auditorium facility on the east side of campus, has earned Iowa State another LEED® Gold certification, the second highest level in the green building rating system. Troxel is Iowa State's eighth LEED-certified building.

LEED (Leadership in Energy and Environmental Design) was introduced by the U.S. Green Building Council in 1998 to measure environmentally sensitive building design, construction, operations and maintenance. The standards in this voluntary program are becoming more stringent as it evolves.

Iowa State's LEED®-certified projects:

Platinum: College of Design Pavilion (2010), State Gym (2012)

Gold: Biorenewables Research Laboratory (2011), Hach Hall (2011), Small Animal Hospital at the Lloyd Veterinary Medicine Center (2013), Troxel Hall (2014)

Silver: Morrill Hall (2008), Bergstrom Football Complex (2014)

LEED measures achievements in five categories plus an innovation category (for exemplary performance in any of the five) and awards a credit total. Troxel Hall scored a 61 on the LEED 110-credit scorecard. The university applied for 66 credits.

Alumnus Doug Troxel, founder of the Change Happens Foundation, which made a $5 million gift to the project, said his family was thrilled to learn of the LEED designation for the building that bears their name.

"As a family, we are committed to supporting environmentally responsible design and construction methods, and we were excited to know our interests were shared by Iowa State leadership," Troxel said. "This high-level LEED certification confirms our dedication to supporting projects with a strong environmental focus. The philanthropic goal of the Change Happens Foundation is to concentrate on the three areas of science, the environment and education.

"Troxel Hall represents the best efforts of that goal and combines those three areas together into one very innovative learning center,"
 he said.

Following are a few examples in each category of how the Troxel project earned LEED credits:

Sustainable site

  • Six bus routes pass within one-fourth mile of the building
  • No vehicle parking stalls were added as part of this project
  • Bicycle parking availability surpasses LEED standards
  • About 65 percent of the roof is planted with vegetation
  • Plantings and white concrete (used minimally) reduce the daylight heat the building site retains

Water efficiency

  • The site has no outdoor irrigation system, and landscaping plants selected reflect this
  • Water use is reduced 36 percent from a building built to state code. Examples include ultra low-flow urinals (one pint of water per flush) in restrooms and aerators in sink faucet heads

Energy and atmosphere

  • Energy cost is 25 percent less than a similar facility built to Iowa code minimums
  • Air delivery ducts are low, air returns are high to keep conditioned air where the people are
  • A plan is in place to meter all utilities (water, chilled water, steam, lighting, electrical outlets, HVAC system) to compare actual performance to performance model

Materials and resources

  • 89 percent of construction waste was diverted from a landfill and recycled instead
  • 29 percent of building materials (by value) contain recycled materials, including carpet, plywood, restroom partitions, lab benches and cabinets
  • 30 percent of construction materials were manufactured or extracted from the earth within 500 miles of Ames
  • Building has areas dedicated to collecting and storing recyclable materials

Indoor environmental quality

  • Paints, carpets, adhesives and sealants used indoors emit no or low levels of toxins
  • Indoor air quality was tested for carbon dioxide levels and toxins prior to occupancy
  • The building's ventilation system draws in 30 percent more outside air than required by state code
  • Occupants can control indoor temperature and lighting, but lack of motion in spaces automatically adjusts levels

The university strives for gold certification or higher on new building and major renovation projects. Pending are LEED applications on the Hansen agriculture teaching facility, Harl Commons and student services mall projects in Curtiss Hall, and phase 2 (Elings and Sukup halls) of the biorenewables complex.