Embodied Carbon Resources

This section includes embodied carbon and life cycle analysis resources, including methodology and tools, policies and codes, and project case studies, to support low carbon construction materials. Introductory guides explain the basics of calculating carbon throughout the life cycle of a building; calculators and web-tools will highlight material carbon intensities, and other references will suggest how materials should be specified.

The built environment accounts for 39% of total carbon emissions in the United States. Operational carbon reduction has been the focus of high-performance building design for years. However, attention should be given to address a building’s embodied carbon. Embodied carbon is the carbon dioxide emitted during the manufacture, transport, and construction of building materials, combined with end of life emissions. Embodied carbon is less discernible than operational carbon, yet an equally important carbon emission source that is causing environmental degradation.

Select case studies provide insight into the design process and materials installed to reduce embodied carbon.
A curated set of tools to calculate whole building life cycle analysis and embodied carbon.
Recent rules, standards, and programs that highlight the environmental impacts of construction materials.

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Embodied Carbon of Buildings and Infrastructure – International Policy Review

This report, commissioned by Forestry Innovation Investment Ltd., offers policy considerations and a potential menu of options that could reduce the impacts of buildings on the environment over their life cycle. The findings and recommendations in the report are based on a review of seven leading examples: Belgium, France, Germany, The Netherlands, Sweden, Switzerland, and the United Kingdom.

Embodied Carbon in Construction Policy Primer for Ontario

This policy primer is intended for design teams and policymakers interested in addressing embodied carbon, emissions associated with construction material extraction, manufacture, and transportation, and building and infrastructure construction, maintenance, and decommissioning in the Ontario context. The primer provides an overview of the concept of embodied carbon and describes how life cycle assessment (LCA) can be used to calculate and minimize life cycle GHG impacts from construction projects.

Bay Area Low-Carbon Concrete Codes Project

The County of Marin developed standards around practical requirements for the composition of concrete that maintains adequate strength and durability for the intended application and at the same time reduces greenhouse gas emissions associated with concrete composition. This code includes pathways for compliance with either reduced cement levels or lower-emission supplementary cementitious materials.

Requirements to the Approval Process for the Supply of Portland Cement Concrete

As part of the City of Portland’s 2016 Sustainable Supply Chain Analysis' to reduce GHG emissions associated with concrete use on City projects, the City requires Portland Cement Concrete (PCC), to have a product-specific Type III Environmental Product Declaration (EPD). Evaluating project-specific EPDs and using those EPDs and related mix performance information will support team as they select lower impact mixes for Portland Cement Concrete.

Carbon Leadership Forum Website of Embodied Carbon Resources

The Carbon Leadership Forum, an industry-academic collaboration hosted at the University of Washington, maintains a database of over 200 embodied carbon resources. Each resource specifies the intended audience as well as the suggested level of expertise.

Concrete Product Category Rule

The Carbon Leadership Forum developed and verified the first version of the North American Product Category Rule (PCR) for Concrete in 2012 for reporting the environmental impacts of concrete. This PCR has been used to develop Environmental Product Declarations (EPDs) for individual concrete suppliers and industry average data for the United States and Canada. In February 2019, Version 2.0 was finalized and published on the National Science Foundation (NSF) website.

Green Buildings Policy for Rezonings

The City of Vancouver adopted the Green Buildings Policy for Rezonings, requiring all projects to report the life cycle equivalent carbon dioxide emissions (i.e. global warming potential impact, or ‘embodied carbon’) of each building, in kgCO2e/m², as calculated by a whole-building life cycle assessment (LCA), for compliance pathway B, "Low Emissions Green Buildings".

CAL Green: California Green Buildings Standards Code

CAL Green is the first-in-the-nation mandatory green building standards code. Section 5.409 of the 2017 Intervening Code Supplements details a pathway to compliance through Life Cycle Analysis. In 2007, the California Buildings Standards Commission developed green building standards in an effort to meet the goals of California’s landmark initiative AB 32, which established a comprehensive program of cost-effective reductions of greenhouse gases (GHG) to 1990 levels by 2020.

Buy Clean California Act

The Buy Clean California Act, AB262, states the Department of General Services (DGS) is required to establish and publish the maximum acceptable Global Warming Potential (GWP). It targets embedded carbon emissions of structural steel (hot-rolled sections, hollow structural sections, and plate), carbon steel rebar, flat glass, and mineral wool board insulation. These materials must have a GWP that does not exceed the limit set by DGS.

Buy Clean Washington Act

Members of the Washington State House of Representatives introduced House Bill (HB) 2412 – Creating the Buy Clean Washington Act to the state legislature, proposing that state agencies awarding construction contracts require environmental product declarations (EPDs) for an eligible list of materials. Although the bill did not move forward for debate and voting in the 2018 legislative session, a modified version of the proposed study was included in the capital budget.

Building for Environmental and Economic Sustainability (BEES) Software

National Institute of Standards and Technology's BEES software provides a powerful technique for selecting cost-effective, environmentally-preferable building products. The tool is based on consensus standards and designed to be practical, flexible, and transparent. BEES Online includes actual environmental and economic performance data for 230 building products.

The ReCiPe Method for Impact Assessment

ReCiPe is a method for the impact assessment (LCIA) in a LCA. The ReCiPe method's objective is to transform the long list of life cycle inventory results into a limited number of indicator scores. There are two mainstream ways to derive characterization factors, i.e. at midpoint level and at endpoint level. ReCiPe calculates 18 midpoint indicators and 3 endpoint indicators.

Chain Management by Life Cycle Assessment (CLMCA)

University of Leiden's CMLCA is a free software tool that supports the technical steps of the life cycle assessment. The focus of the program is on advanced computational aspects of life cycle inventory calculations. The CML-IA is a database that contains characterization factors for life cycle impact assessment (LCIA) and is easily read by the CMLCA software program including characterization factors for all baseline characterization methods mentioned in the Handbook on LCA, such as GWP100, POCP, HTPinf and AP.

Building Transparency: Embodied Carbon in Construction (EC3 LCA Tool)

The Carbon Leadership Forum developed an open source tool to help construction professionals efficiently quantify, report, and reduce embodied carbon. The Embodied Carbon Construction Calculator (EC3) is a free tool that allows professionals to find and compare materials, plan and compare buildings, declare products, and verify and audit EPDs for incorporation into full LCA.

Motivating Low-Carbon Construction: Opportunities and Challenges

The Carbon Leadership Forum published this white paper outlining a roadmap for action and recommendations for motivating low carbon construction in the marketplace. The paper details the steps necessary for overcoming challenges like perceived low demand and lack of federal funding and leadership.

Life Cycle Assessment of Buildings: Technical Guidance

The Carbon Leadership Forum's Technical Guidance provides detailed recommendations for conducting life cycle assessments of buildings and is directed towards seasoned LCA practitioners and LCA tool developers in North America.

Life Cycle Assessment of Buildings: A Practice Guide

The Carbon Leadership Forum published this guide to introduce the concept of life cycle assessment to building professionals. The Practice Guide is divided into two parts: 1. an introduction that addresses how buildings impact the environment and how LCA can be used to quantify environmental impact and 2. an implementation section that describes the five key steps to conducting an LCA of a building.

Comparison of Methodologies for Whole Building Life Cycle Assessment: A Review

The University of Washington's study reviews whole building life cycle assessment (WBLCA) methods and distinguishes the main differences and similarities among current guidelines available to comply with green building rating systems (GBRS), and existing product category rule (PCR). The Leadership in Energy and Environmental Design V4 (LEED), Green Globes, and the Deutsche Gesellschaft für Nachhaltiges Bauen (DGNB) System are highlighted as the main GBRS for comparison. The PCR for building comparison include the PCR UN CPC 531 Buildings (PCR 2014:02 Buildings, Version 1.0), International EPD system and Standards ISO 14040:2006 and ISO 14044:2006 are used as the basis for comparison.

AIA Guide to Building Life Cycle Assessment in Practice

In this paper, the American Institute of Architects (AIA) provides guidelines to help architects understand and use LCA methodology as part of the design process by identifying scenarios for the use of whole building LCA. AIA establishes a basic understanding of LCA for the building industry, the utility of LCA, and proposed suggestions for conducting LCA. The state of research was reviewed to find answers to present limitations of use of LCA in practice. The paper shows that LCA results help answer numerous questions that arise during the design and construction of a green building. It can reinforce the decisions made by architects by providing a scientific justification for those decisions.

Critical Issues When Comparing Whole Building & Building Product Environmental Performance

MIT Concrete Sustainability Hub's paper aims to address critical issues and make recommendations to practitioners and those developing guidance to enable more robust comparisons of building products and whole buildings. The paper classifies critical issues when comparing building and building product environmental performance into two categories: system boundaries and analytical approach. The paper recognizes the desire to perform comparisons today that cannot be put off until methodologies advance further and offers two kinds of recommendations: current practice and future advances.

Athena Guide to Whole-Building LCA in Green Building Programs

The Athena Sustainable Materials Institute is the pioneer of whole-building life cycle assessment (LCA) in North America. This guide provides tips on how to incorporate LCA during the building design process and presents the Institute's supplementary best-practice recommendations for performing whole building LCA. It also offers an introduction to the Athena Impact Estimator for Building, which makes LCA accessible for architects, engineers, and other non-LCA experts in design and construction professions.

LCA for Low Carbon Construction: Embodied Carbon Benchmark Study

The Embodied Carbon Benchmark Study is the first stage of the LCA for Low Carbon Construction Project funded by The Charles Pankow Foundation, Skanska USA and Oregon Department of Environmental Quality. The project compiled the largest known database of building embodied carbon and created an interactive database. This stage of the project established consensus on the order of magnitude of typical building embodied carbon, identified sources of uncertainty, and outlined strategies to overcome this uncertainty.

Methodology to Calculate Embodied Carbon

This RICS' guidance note builds on a previous 2012 paper, Methodology to Calculate Embodied Carbon of Materials, and expands to include emissions from other life cycle stages. The main aim is to provide a framework of practical guidance for surveyors on how to calculate embodied carbon emissions associated with their projects.

Enhancing the Value of Life Cycle Assessment

Deloitt's paper outlines how LCA can be used to assess the end-to-end environmental impacts of a business decision on overall value creation. The paper evaluates several value-creating business objectives, and shows how the LCA methodology can help companies achieve these goals.

Study on Incentives Driving Improvement of Environmental Performance of Companies

In August 2011, the European Commission (DG Environment) appointed Ecorys to carry out a study on incentives driving the improvement of the environmental performance of companies. The overall objective of the study was to analyze the effectiveness of incentives in changing the environmental behavior of companies (including the effects of different mixes of incentives). The paper argues that LCA should be taken into consideration when forming and evaluating incentives for environmental performance improvement.

Buy Clean California Incentive Program

USGBC-LA assists manufacturers of steel, flat glass, and mineral wool insulation through the Buy Clean Incentive Program by offering incentives of up to $15,000. The incentive can be used to acquire their Environmental Product Declaration and green their own supply chain and manufacturing processes.

USDA Mass Timber Material Quantities Final Report

This study explores how mass timber buildings can be optimized for material efficiency and support a regionally-specific life cycle assessment case study of a mass timber office building in the Pacific Northwest. The University of Washington Architecture team defined a reference commercial office building using heavy timber/cross-laminated timber (CLT) to substitute for conventional construction. The School of Forest Resources Team developed regionally-specific LCA models to evaluate the environmental impact of potential CLT production in the Olympic Peninsula.

Life Cycle Assessment of Residential Buildings: A Case Study in Canada

The World Academy of Science, Engineering and Technology published this Life Cycle Assessment in the International Journal of Energy and Environmental Engineering. LCA methodology was employed to study the primary energy uses and associated environmental impacts of different phases (i.e. product, construction, use, end of life, and beyond building life) for residential buildings. Four different alternatives of residential buildings in Vancouver (BC, Canada) with a 50-year lifespan have been evaluated, including High Rise Apartment (HRA), Low Rise Apartment (LRA), Single family Attached House (SAH), and Single family Detached House (SDH). Life cycle performance of the buildings is evaluated for embodied energy, embodied environmental impacts, operational energy, operational environmental impacts, total life cycle energy, and total life cycle environmental impacts.

A Life Cycle Approach to Prioritizing Methods of Preventing Waste from the Residential Construction Sector in the State of Oregon

The purpose of this project by Oregon Department of Environmental Quality was to evaluate the environmental benefits of potential actions aimed at reducing material use and preventing waste during the design, construction, maintenance, and demolition of residential buildings within the state of Oregon. Within this report, the phrase waste prevention practices is used to describe practices that reduce material use or reuse materials - and subsequently reduce waste generation.

Buy Clean Washington Study

The Buy Clean Washington Study presents embodied carbon policies and proposes methods to categorize structural materials and report structural material quantities and origins.

LCA for Low Carbon Construction: Estimates of Embodied Carbon for Mechanical, Electrical, Plumbing, and Tenant Improvements

This study is an extension of the Life Cycle Assessment (LCA) for Low Carbon Construction Project. The Oregon Department of Environmental Quality selected mechanical, electrical, and plumbing (MEP) and tenant improvement (TI) as research topics of interest to investigate because there is very little data on these environmental impacts. This study presents estimates of material quantities and environmental impacts for commercial office buildings in the Pacific Northwest. This study is funded by the Charles Pankow Foundation, the Oregon Department of Environmental Quality, and Skanska USA.