OVERVIEW We are pleased to release Turner’s inaugural Embodied Carbon Baseline Report for 2022 on the following page. This report reflects emerging trends in the greenhouse gas emissions associated with a sample of our projects’ material footprint. Below is a snapshot of initial conclusions and opportunities for future reduction of embodied carbon in the building materials studied. We hope this benchmarking report will serve as a valuable resource in affecting universal change in the way we build, work, and live in the built environment.
SUMMARY This Report corroborates some widely accepted conclusions relating to the embodied carbon footprint of new commercial buildings in the United States In particular, this study indicates:
• Concrete and steel materials used in the foundation and structural systems of a building make up a significant portion of its total embodied carbon footprint
TRADE SPECIFIC DETAILS of this Embodied Carbon Baseline include:
CONCRETE:
• For the purpose of this study, concrete includes ready-mixed concrete, precast concrete, concrete masonry units (CMU), aggregate, shotcrete, and flowable fill
• Cementitious soil stabilization is not included in this study, although early indications show that, when used, this may be a strong contributor to a building’s overall embodied carbon footprint
• In this study, concrete materials generated an average of 49% of a building’s structural and foundation-related embodied carbon footprint.
STRUCTURAL STEEL:
• The size of a building, as measured by gross floor area, is a strong indicator for its overall embodied carbon footprint FOR QUESTIONS OR MORE INFORMATION: Rowan Parris Embodied Carbon Program
rparris @tcco.com 980. 402 .4881
Lindsey Landwehr-Fasules
Director - Sustainability lfasules@tcco.com
312 . 446 .0944 Julia Gisewite V.P. Sustainability
jgisewite @tcco.com
202 . 439.9970
• For the purpose of this study, structural steel includes hot-rolled sections, concrete reinforcing (rebar, wire mesh, and pre- or post- tensioning tendons), metal decks, plate steel, hollow sections, and merchant bar.
• In this study, steel materials generated an average of 51% of a building’s structural and foundation-related embodied carbon footprint
• The largest contributor within the structural steel category in this study are hotrolled sections, which make up an average of 49% of the structural steel-related embodied carbon footprint.
ADDITIONAL MATERIAL CATEGORIES :
• Several material types not included in this study show early indications of significance, including:
o Aluminum
o Glass*
o Insulation
o Wood*
• Future work may explore these additional material categories to expand the scope of this study Materials denoted with an asterisk (*) indicate high priorities in line with ESG reporting requirements through Turner’s parent company, Hochtief.
• More information and other benchmarking efforts to address embodied carbon in buildings can be found at https://carbonleadershipforum org/research/
FINDINGS METHODOLOGY
WHAT IS IN THIS REPORT? Among the information included in this publication, and of special importance, is the Turner Embodied Carbon Coefficient. This multiplier was determined by analyzing a sample of Turner projects representing approximately 60% of 2022 Annual Revenue. Sampled projects were modeled in the Embodied Carbon in Construction Calculator (EC3)1 using material quantities of concrete and steel in the foundations and structure along with industry embodied carbon data. Several project characteristics2 were compared using statistical analyses to determine which, if any, proved to be statistically significant variables for assessing embodied carbon project baselines going forward.
Concrete makes up 49% of the embodied carbon in the foundation and structure of buildings sampled in this study.
Each point on the scatterplot below represents a project from the study. The percent of that building’s embodied carbon generated from concrete is on the y-axis.
Regression analyses were conducted on several project characteristics2 to determine possible relationships to the carbon intensity of the buildings studied. Three main relationships were hypothesized:
• FLOOR AREA – gross square foot area of building
• REVENUE – gross U.S. dollar volume of the project
• CARBON – A1-A3 stage3 emissions from concrete & steel materials used in the building’s structure and foundations Although visually similar in the graphs below at a glance, Floor Area and Carbon values appear more closely aligned than Revenue and Carbon values. Regression results confirm this according to the R-Square and P-value guidelines to the right.
WHAT’S IN A RELATIONSHIP?
32 projects were modeled for this study with the following criteria:
• Primary scope is awarded to Turner,
• Building is ground-up, new construction, and
• Project is currently in Preconstruction (at the time of selection in Q2 2022). Projects were strategically selected to be representative of Turner’s company portfolio, with a variety of market segments and total of $ 12.3B and 17.8M SF. This accounts for approximately 60% of Turner’s 2022 portfolio.
A range of building sizes are represented in this study, from 39,700 ft2 at minimum to just shy of 2.6M ft2 at maximum. The average (mean) gross floor area is 556,740 ft2, whereas the median is 390,174 ft2, indicating a slightly positively skewed dataset.
Steel makes up 51% of the embodied carbon in the foundation and structure of buildings sampled in this study.
Each point on the scatterplot below represents a project from the study. The percent of that building’s embodied carbon generated from steel is on the y-axis.
Hot-rolled sections make up 49% of steel embodied carbon in the study.
The next largest contributors to the steel carbon footprint in the projects studied are concrete reinforcing and metal decks, followed by plate steel, hollow sections, and merchant bar.
35.35 kg CO2e/SF is the magic number resulting from the regression model for project carbon v. gross floor area above.
A project-specific EC3 model using material quantities and EPD data is preferred for accurate benchmarking and reduction tracking, but Turner’s Embodied Carbon Coefficient can be used as an initial approximation or starting point.
Total project revenue is distributed similarly in this dataset, with a positive skew indicated by a smaller median ($192.8M) than the mean ($383.3M). The minimum project volume in this study is just over $15M and the maximum is around $2B.
This embodied carbon coefficient can be used to quickly and easily approximate a baseline for the embodied carbon footprint of a project or portfolio’s structure and foundation scope.
For example, the average project size in the study is 556,740 ft2, so the baseline embodied carbon of the foundation & structure for a building of this size would be:
Projects across 19 different Business Units were modeled in this study. Most were primarily steel composite structures, though a few were primarily concrete or timber.
Project Carbon v. Gross Floor Area
