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A New Framework for Teaching the Triple Bottom Line: The Sustainability Triangle and the Sustainability Index

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2017 ASEE Annual Conference & Exposition


Columbus, Ohio

Publication Date

June 24, 2017

Start Date

June 24, 2017

End Date

June 28, 2017

Conference Session

Integrating Sustainability and Social Responsibility into the Curriculum

Tagged Division

Civil Engineering

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Paper Authors


Michael R. Penn University of Wisconsin, Platteville

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Professor of Civil and Environmental Engineering. Lead author of the textbook, Introduction to Infrastructure: An Introduction to Civil and Environmental Engineering. Contributor to the ASCE Report Card on Wisconsin's Infrastructure.

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Kristina M. Fields University of Wisconsin, Platteville

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Dr. Kristina Fields is a civil engineering professor focusing her coursework on transportation, construction, and computer applications of civil and environmental engineering. She is active in pre-college engineering outreach and improving non-motorized transportation infrastructure.

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Integrating the concept of sustainability into civil and environmental engineering curricula is important and challenging. For decades engineering students have been taught to design systems and recommend solutions based on cost. The triple bottom line approach suggests that cost alone is not the deciding factor-- social and environmental impacts should also be considered. The triple bottom line is commonly referred to as “the three P’s: People, Planet and Profit.” Unfortunately, social and environmental impacts are often secondary, qualitative considerations. In an attempt to raise student awareness of the need to balance the three P’s, a new framework was developed. The Sustainability Triangle is a simple and effective method to visualize the balance of the three P’s for a design. Students must make semi-quantitative evaluations, on a zero to 100 scale, for each of the three P’s which in turn are used for form a triangle. The scores for each P are then used to calculate a Sustainability Index (SI) which is defined as: SI = [ (the sum of the scores of each of the three P’s) – (the difference between the maximum and minimum scores of the three P’s) ]. The SI value is influenced by the imbalance between individual P scores. For example, a design alternative is given scores of 90, 80 and 70 for people, planet and profit respectively. The SI would equal [(90+80+70) - (90-70)], or 220 out of a 300 possible points as opposed to the simple sum of the three P’s which would be 240. This evaluation can be completed for multiple design alternatives, and the most sustainable (or least unsustainable) alternative would be that with the highest SI value. This paper will demonstrate how these tools are introduced to students, and how an in-class example provides an opportunity for students to utilize the tool for decision-making.

Penn, M. R., & Fields, K. M. (2017, June), A New Framework for Teaching the Triple Bottom Line: The Sustainability Triangle and the Sustainability Index Paper presented at 2017 ASEE Annual Conference & Exposition, Columbus, Ohio. 10.18260/1-2--27491

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