Outpatient Care Pavilion at Northwestern Memorial Hospital in Chicago, Illinois.
The AIA 2030 Commitment
In the United States, buildings contribute about third of all greenhouse gas emissions. Thornton Tomasetti has acknowledged that as architects and engineers we have a responsibility to a more sustainable future by signing on to the American Institute of Architects (AIA) 2030 Commitment. This rapidly expanding national initiative challenges the AEC industry to achieve complete carbon neutrality within their portfolios by the year 2030. AIA provides standardized metrics and a uniform format for reporting and evaluating the impact of design decisions – such as heating and cooling systems, daylight and insulation – on a building’s energy performance. Participants use this framework to measure each design choice against stringent standards to optimize their building’s operations and reduce its energy and carbon footprint.
Unfortunately, these tools, created for architects, did not apply to our work at Thornton Tomasetti. At the time of signing the Commitment, our company was composed largely of structural engineers. Being the first structural engineering firm to accept this challenge in 2011, a framework to measure the energy and carbon efficiency of the structural aspect of building projects did not yet exist. The impact we were hoping to reduce went down to the bones of a building – the selection of structural materials and patterns of their assembly. Unlike architects, structural engineers do not have a large impact on a building’s operational energy, but we believe that the impact of each structural material from extraction to eventual disposal – the lifetime “embodied energy and carbon” – must be counted in a building’s assessment to get the real picture of its environmental impact.
We decided to develop our own calculator to measure the embodied impacts of our structural design decisions. Our tool would tally the amounts of structural materials in each project and evaluate them based on methods of raw material extraction, the distance traveled between the extraction point and manufacturing plant, the manufacturing process, the recycled content of the finished product, and transportation from the plant to our building site. This whole life cycle analysis of each material would also include the potential impact of its future disposal or reuse.
At this point, there is no established canon of best practices for structural energy and carbon efficiency – our calculator is among just a few tools for measurement currently being tested and developed.
In 2012, we began evaluating the embodied energy and carbon of all buildings contributed to by engineers working in our two largest offices in New York and Chicago. These case studies have allowed us to approximate the break-down of life cycle impacts of various building materials in an average commercial building, and compare the embodied impact of the two offices’ portfolios against one another. With each use, the calculator’s strengths and areas needing improvement become more apparent. As we develop this tool, we are growing in our understanding of the issues at hand and moving closer to achieving our goal of carbon neutrality.
In the near future, we hope to use this tool to measure the impact of all projects in our 27 offices worldwide. Coming from a holistic perspective on sustainability, we believe that green design must go deeper than operations and address the very foundations of a building. We believe that impact analysis must be considered on an expanded timeline that reaches back to the original extraction of our materials and forward to the management of the materials when the building reaches the end of its life.
In keeping with this attitude, we are walking the walk by measuring the impact of our internal operations. 2012 is our baseline year for a company-wide carbon footprint inventory that will be updated and evaluated annually. Our footprint calculator tracks office electricity use, heating and cooling fuel use, commuting, business travel, purchasing and waste management to generate total emissions per office and emissions per capita. We hope the tool will help us isolate challenging areas and aid us in reducing our internal environmental impact.
Here at Thornton Tomasetti, we work from the ground up. To us, sustainability means getting down to brass tacks and scrutinizing the very framework of our projects and our operations. As we all try to grow greener, we have to remember to take nothing for granted. In our industry, traditional methods of material selection and basic design principles did not necessarily take sustainability or lifetime environmental impact into consideration. However, in our industry, we are very much aware that innovation and improvement is always possible!
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