Brooklyn, NY According to Thornton Tomasetti, the international engineering firm, One John St., a 12-story, 42-unit residential building, has achieved LEED v2009 BD+C Gold certification from the U.S. Green Building Council.
Working with Alloy, the project owner/developer and architect, Thornton Tomasetti provided sustainability consulting services for the 125,000 s/f building in Brooklyn Bridge Park. The building was completed in August 2016 at a cost of $42 million.
Thornton Tomasetti was retained in the early design stages to develop a sustainability strategy that targeted a minimum 50% reduction in greenhouse gas emissions. In addition to LEED consulting services, it provided energy modeling and building science analysis, which led to improved thermal performance of the building envelope and increased overall energy efficiency. The firm also helped right-size HVAC system design and select controls for improved comfort and performance.
A number of sustainable measures employed in the building have resulted in both energy and cost savings. These include the installation of high-efficiency HVAC systems, the use of locally sourced and recycled materials, such as Forest Stewardship Council (FSC) certified wood floors and cabinets, and LED high-efficiency lighting.
Low-flow fixtures reduced water use by 30%, equating to an energy savings of 24% above code. A cogeneration plant that produces electricity and transfers waste-heat to the building’s domestic hot water supply helps to reduce fuel consumption as well as other energy costs. A variable refrigerant flow system is also used to transfer heat throughout the building via a load sharing method.
One of the project’s challenges was minimizing traffic and subway noise to ensure resident comfort.Thornton Tomasetti implemented a selection of progressive glazing with a triple-pane window system that improved the acoustics as well as the thermal envelope of the building.
The windows of One John St. become progressively smaller as the building ascends. ThorntonTomasetti performed a thermal analysis to reduce thermal bridging and increase insulation around the windows, which resulted in greater energy efficiency thanks to integrated design.
Colin Schless, PHC, LEED AP BD+C, associate, San Francisco, Thornton Tomasetti, said, “Collaborating with a developer that is also the project owner and architect added a unique perspective to the design process. Every decision was analyzed for energy efficiency, cost-effectiveness, and ultimately, comfort. The result was a high-performance building that achieved LEED Gold and stands out as a new landmark on the Brooklyn waterfront.”
AJ Pires, president, Alloy Development, said, “Thornton Tomasetti was able to simplify complex project analyses and communicate it clearly to us. The firm helped Alloy, as the project’s owner, developer and architect, make valuable design decisions that ultimately resulted in a better project overall.”