Faculty and Researcher Articles and Data

Permanent URI for this collectionhttps://digital.lib.washington.edu/handle/1773/47137

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Biogenic Carbon Accounting in Wood Environmental Product Declarations: A comparison of methodologies in European and North American Wood Product EPDs
(2025-05-09) Ellingboe, Ethan; Hariadi, Karisha Shahnaz; Carlisle, Stephanie
Environmental product declarations (EPDs) are a key mechanism for reporting the environmental impacts of construction materials – including wood products. EPDs are standardized, third-party-verified documents that aim to clearly and transparently report the environmental impacts associated with production, use, and disposal of a product calculated according to standard life cycle assessment (LCA) accounting rules. Structural wood products are touted globally for their low environmental impacts relative to other fossil-intensive construction materials. EPDs are one mechanism – often used in combination with certifications, owners sourcing requirements, and others – used by the building industry to understand the relative impact of wood products. However, the environmental benefit of biogenic carbon sequestration and storage associated with forest growth and production and use of structural wood products is currently reported differently across regions according to varying accounting mechanisms for wood EPDs in different regions. As EPDs grow increasingly important in the context of global policy and trade, these differences in rules and accounting methods applied to structural wood product EPDs merit greater attention. This report dives deep into the accounting and reporting standards for structural and architectural wood product EPDs in Europe and North America with the goal of (1) identifying key challenges in comparability based on current standards and (2) highlighting the largest opportunities to increase the comparability of product category rules (PCRs) and related international LCA standards moving forward. The greatest differences between European and North American wood product EPDs stem from differences between these regional parent LCA standards for construction products: EN 15804:2012+A2:2019 (CEN, 2019) and ISO 21930 (ISO, 2017). Despite global agreement on the general framework of EPDs, inherent differences in the emissions and removals included in European and North American wood EPDs prevent direct comparison of products across markets due to their different approaches to quantification and reporting of biogenic carbon removals and emissions.
A Literature Review on the Health Impacts of Wood and Mass Timber Buildings
(2025-05-09) Hariadi, Karisha Shahnaz; Carlisle, Stephanie
In response to the pressing need to reduce the environmental impact of the built environment, there has been growing interest in using bio-based building materials, including mass timber. Apart from potentially offering a lower carbon footprint compared to conventional structural materials, one emerging area of research is the potential positive and negative health impacts that mass timber may have on building occupants. There is a robust and growing body of work on the linkages between human health and the built environment. While there is a larger body of work on the health impacts of wood used in the built environment more broadly, few studies have looked specifically at mass timber. Additionally, when mass timber buildings have been studied, the research is focused heavily on mass timber used in commercial, educational, and public buildings, with relatively fewer applications in residential construction. As a result, research on its health impacts in residential settings is still limited. Linkages between construction material and occupant health and well-being are challenging to prove. This paper is a literature review of the available scientific and industry literature on the documented health impacts of wood and mass timber in construction. The key health impacts discussed are improved indoor air quality, improved thermal comfort, enhanced cognitive performance, reduced stress levels, and physiological relaxation. This paper also explores trends in the types of buildings and occupants studied, identifies key researchers and organizations, and highlights gaps and opportunities for future research.
The California Carbon Report Summary: Six Key Takeaways for Policymakers
(2024-05-13) Benke, Brad; Roberts, Matt; Lewis, Meghan; Shen, Yang; Carlisle, Steph; Chafart, Mel; Simonen, Kate
In early 2024, we published The California Carbon Report: An Analysis of the Embodied and Operational Carbon Impacts of 30 Buildings, which explored the magnitude and timing of embodied and operational carbon emissions for 30 real building projects in California. This included estimating the whole life carbon impacts of the buildings over time, exploring variability across different projects, and identifying top contributors to carbon emissions. This document serves as a summary of key takeaways from the full report. Though it is relevant for building designers, owners, builders, and engineers, the target audience for this document is policymakers working to decarbonize the building sector in the State of California. The six key takeaways for policymakers are: 1. Embodied carbon impacts are substantial 2. The timing of emissions matters 3. It is critical to decarbonize the grid AND reduce fossil fuels in buildings 4. Concrete and steel emissions are big, but they aren’t the only things that matter 5. Building-scale assessments are valuable 6. We don’t yet know the full picture
The California Carbon Report: An Analysis of the Embodied and Operational Carbon Impacts of 30 Buildings
(2024-04-22) Benke, Brad; Roberts, Matt; Shen, Yang; Carlisle, Steph; Chafart, Mel; Simonen, Kate
Actors in the built environment are promoting strategies targeted at reducing the environmental impacts of buildings. Many government agencies, design companies, builders, and developers have proposed voluntary net-zero commitments to drive change across the sector. Similarly, policymakers at both the state and national levels have been passing successful legislation to achieve mandatory emissions reductions, and many of these policies rely heavily on building-related decarbonization. Though all of these commitments and policies vary in their scopes and ambition levels, they all ultimately seek to reduce GHG emissions in alignment with Paris Agreement targets. Still, building decarbonization at scale has continued to prove challenging. In this study, we investigated the use of whole life carbon assessment (WLCA) through a sample of 30 new construction building projects located in the State of California that were sourced from design practitioners as part of the CLF WBLCA Benchmark Study (v2). California was chosen for this preliminary study owing to its unique climate, large population, geographic size, rapidly decarbonizing electrical grid, ambitious climate targets, and quickly evolving policy landscape. By conducting this analysis, we sought to answer the following questions: - What is the projected balance of emissions between embodied and operational carbon over time for a sample of new buildings in California? - What are reasonable estimates of embodied and operational carbon intensities for the buildings analyzed? - What are the most significant contributors to embodied carbon impacts from different buildings’ scopes, elements, or materials? - What are the current gaps and challenges within industry practices toward developing comprehensive whole life carbon assessments? - How do the results vary based on changes to LCA methods and assumptions?
CLF WBLCA Benchmark Study (v2) Data Entry Template v1.0
(2024-04-18) Carbon Leadership Forum:; Benke, Brad; Chafart, Mel; Carlisle, Steph
This document was developed to support data collection for the CLF WBLCA Benchmark Study (v2). It is not intended to serve as a template, set of requirements, guidance document, or recommendations for other LCA modeling, reporting, or data collection efforts. This document is meant to be used in conjunction with the CLF WBLCA Benchmark Study (v2) Data Collection User Guide v1.0.
CLF WBLCA Benchmark Study (v2) Data Collection User Guide v1.0
(2024-04-19) Carbon Leadership Forum:; Benke, Brad; Chafart, Mel; Carlisle, Steph
The goal of this Data Collection User Guide is to provide instructions and assistance for data contributors seeking to submit building project data and whole-building life cycle assessment results to the CLF WBLCA Benchmark Study (v2). It is not intended to serve as a template, set of requirements, guidance document, or recommendations for other LCA modeling, reporting, or data collection efforts. This user guide provides detailed requirements and descriptions of the types of data that will be collected for this research project and should be accompanied by the CLF WBLCA Benchmark Study (v2) Data Entry Template v1.0.
2023 Carbon Leadership Forum North American Material Baselines - Report & Appendices
(2023-04) Waldman, Brook; Hyatt, Allison; Carlisle, Stephanie; Palmeri, Jordan; Simonen, Kathrina
The CLF North American Material Baselines Report provides a snapshot of the state of Environmental Product Declarations (EPDs) for North American-produced construction materials. The report includes background and methodology, Baseline values, and a detailed appendix for each material category. The CLF Baseline values represent an estimate of industry-average GHG emissions for construction materials. An overwhelming majority of the CLF Baselines published in this report are based on a North American industry-wide EPD if one was available at the time of publication. As such, it is appropriate to use this number as a rough estimate of a product type’s embodied carbon before a specific product has been selected or as a reference value against which product-level comparisons can be made. Each material category has a detailed appendix that includes a description of the embodied carbon impacts, the available EPDs, and summary statistics. The Appendices in this report allow users to better understand the availability of existing industry-wide and product EPDs, and the variability of product types across a category. The snapshot of available EPDs summarized in each Appendix was assembled using the EC3 database in Fall 2022.
Pacific Coast Collaborative Embodied Carbon Policy Case Studies
(2023-01-25) Kalsman, Megan; Lewis, Meghan; Simonen, Kate
This document highlights ten low-carbon construction policy case studies from the PCC region which are examples of successfully passed policies targeting embodied carbon. Each case explores the development process, challenges faced, and lessons learned through the policy process. Information was gathered from interviews with PCC members who were involved in the policy, publically available policy reports, as well as interviews from the implementing agency of the policy.
Developing an Embodied Carbon Policy Reduction Calculator - Quantifying the embodied emissions reduction potentials of city policies
(Carbon Leadership Forum, 2022-04) Benke, Brad; Lewis, Meghan; Carlisle, Stephanie; Huang, Monica; Simonen, Kate
In this study, four prototype embodied carbon policy calculators were developed and tested on three different C40 pilot cities including New York City, Portland, and Austin. The intent of the study was to prove the concept and functionality of developing calculators for estimating embodied carbon at the scale of a city and assessing whether this type of data would be useful for developing and communicating embodied carbon policies. The prototype calculators proved effective for estimating order-of-magnitude embodied carbon impacts of the different policies and were able to generate meaningful outputs that, with additional future research and development, could help inform real-world policy decision-making. For instance, preliminary results from the prototype calculators indicated that requiring reductions in building embodied carbon intensity was the most impactful for making city-scale reductions, followed by incentivizing adaptive reuse. However, multiple significant data and functionality gaps were identified as being critical for future development before the calculators could be applied in a real-world policy setting.
2021 Carbon Leadership Forum Material Baseline Report (version 2)
(University of Washington Carbon Leadership Forum, 2021-07) Carlisle, Stephanie; Waldman, Brook; Lewis, Meghan; Simonen, Kathrina
The building industry has an essential role to play in tackling climate change associatedwith building construction and materials manufacturing. Our present understanding of the importance of embodied carbon has been enabled by rigorous quantitative modeling that tracks carbon emissions across the full life of materials and products, using life cycle assessment (LCA). In recent years, the building industry has adopted LCA as the globally accepted method for evaluating and communicating environmental impacts, and applied these methods to the study of materials, products, and assemblies. LCA data and results are essential for guiding science-based efforts to decarbonize buildings and infrastructure. The Carbon Leadership Forum (CLF) is part of a broad movement working to drive down the embodied carbon of building materials and products by encouraging the disclosure of high-quality embodied carbon data by manufacturers. It is essential that designers, owners, and policymakers have access to verified, third-party reviewed and published data on building materials and products in order to facilitate procurement decisions, set decarbonization targets, and inform design. One tool for achieving this goal has been the collection and use of Environmental Product Declarations (EPDs) to inform decision-making. EPDs are third party-verified documents based on LCA models, written in conformance with international standards, that report the environmental impacts of a product. These declarations can be used to track supply chain-specific product data and compare products if the products are functionally equivalent and have aligned scopes. The development of material baselines originated in support of the Embodied Carbon in Construction Calculator (EC3) tool, which aims to collect all third-part-reviewed EPDs for published categories. The EC3 Baselines were originally published in 2019. This document supersedes those and the 2021 CLF Material Baseline Report version 1. (See the Updates section for a list of changes since the previous version.) The EC3 tool and its open-access database of digital EPDs is one source for accessing and evaluating available EPDs and the relative carbon impacts that they report. Such databases support designers, owners, and policymakers in selecting low-carbon products during procurement and design. These databases are dynamic, updated constantly as new products are added and upstream data on key processes, such as carbon intensity of regional electricity grids, are revised. In order to set achievable targets, it is necessary to have a baseline from which to compare products within a material or product category. This document provides an overview of the 2021 CLF Material Baselines published by the CLF. This report constitutes an update to 2019 Beta Baselines and 2021 CLF Material Baselines Report version 1 with improved data sourcing, citation, and categories.
An Evaluation of Wearable Sensors and Their Placements for Analyzing Construction Worker’s Trunk Posture in Laboratory Conditions
(2021-07-15) Lee, Wonil; Seto, Edmund; Lin, Ken-Yu; Migliaccio, Giovanni C
This study investigates the effect of sensor placement on the analysis of trunk posture for construction activities using two off-the-shelf systems. Experiments were performed using a single-parameter monitoring wearable sensor (SPMWS), the ActiGraph GT9X Link, which was worn at six locations on the body, and a multiparameter monitoring wearable sensor (MPMWS), the Zephyr BioHarnessTM3, which was worn at two body positions. One healthy male was recruited and conducted 10 experiment sessions to repeat measurements of trunk posture within our study. Measurements of upper-body thoracic bending posture during the lifting and lowering of raised deck materials in a laboratory setting were compared against video-captured observations of posture. The measurements from the two sensors were found to be in agreement during slow-motion symmetric bending activities with a target bending of ≤ 45º. However, for asymmetric bending tasks, when the SPMWS was placed on the chest, its readings were substantially different from those of the MPMWS worn on the chest or under the armpit.

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