Green Roofs - Living Architecture Monitor - Spring 2010 - (Page 24)

RESEARCH e LeNs Of EmeRgY eMs tHRoUGH TH nG SYsT OK AT tHReE rOoFI A COmPArATIVe Lo L. CARtEr TIlLeY & TImOtHY BY JOHn R. SCHrAM sKI, DAVID R. EeNInG THe Gr oOf SYsTeM GrEeN R The upcoming CitiesAlive! 8th Annual Green Roof and Wall Conference (Nov. 30 to Dec 3, 2010 in Vancouver, Canada) will explore new research, design and policy development opportunities to improve industry’s ability to mitigate and adapt to the challenges of climate change. This is a summary of a paper entitled Comparative Embodied Energy Analysis to Assess Green Roof Sustainability presented in Atlanta, Georgia at Green Roofs for Healthy Cities’ 7th annual conference in 2009 by John R. Schramski, University of Georgia; David R. Tilley, University of Maryland; and Timothy L. Carter, University of Georgia. The complete paper is available in the Living Architecture Toolbox, GRHC’s new Member-based online platform at www.greenroofs.org. INTRODUCTION Although the economic costs of roofing projects are easily calculated, the environmental impact (or cost) of constructing these technologies is not readily apparent. To begin addressing this concern, we conducted a comparative embodied energy analysis (for this study we use emergy analysis) of two “green” engineered roofs (extensive planted and cool/reflective) and a traditional modified bitumen roof. Emergy—correctly spelled with an “m” and short for energy memory—is defined as the available energy of one kind used up both directly and indirectly in the past to make a product or service that exists in the present (Odum 1986, 1988, 1996; Campbell 2008). Emergy evaluations usually use solar joules (identified as emjoules) as the base dimensional unit. The advantage of using emergy is that all 24 LIVING ARCHITECTURE MONITOR SPRING 2010 environmental, social and economic quantities expressed in emergy’s solar emjoules can be compared on the same accounting ledger subsequently serving as a common measure of often disparate system attributes. Although emergy methodology is still under development, its results and corresponding insights are significant and growing (Brown & Herendeen 1996, Campbell et al. 2005) with the first emergy evaluation of a green roof being performed by Reid Coffman (Coffman 2007). We conducted an emergy analysis of three recently installed roofs, two “green” engineered and one traditional as shown in Table 1 (next page). The baseline is a modified bitumen (MB) assembly. The two “green” engineered roofs are a cool reflective thermoplastic polyolefin (TPO) roof and an extensive vegetated green roof. http://www.greenroofs.org

Table of Contents for the Digital Edition of Green Roofs - Living Architecture Monitor - Spring 2010

Green Roofs - Living Architecture Monitor - Spring 2010
Contents
From the Founder
Letters
Strata
Roofing Industry Research Summit
New LAM Editorial Advisory Board Kicks Off
On the Roof With Steve Windhager
Green Philly
Taking the Pulse
Greening the Green Roof System
More Bees, Please!
Dampening Green Roof Fire Risk
New Online Tools for Green Roof and Wall Professionals
New Corporate Members
New GRPS
GHRC Professional Development Calendar
Building Green Together

Green Roofs - Living Architecture Monitor - Spring 2010