openIMPACT is a project to develop a free, open-access environmental impact database of high-impact building materials.  Its early focus is GWP for North American products, but the underlying models are suitable for most regions and impact categories.

EC3’s EPD database is best for understanding the impact of individually procured products, EPDs are not the appropriate embodied carbon data to use in early design.  EPD data is not market-weighted, and sufficient  EPDs may not be available to fully capture potential range of impacts in a particular product market. Industry-wide EPDs are supposed to reflect this market weighing, but unfortunately have mostly resorted to reporting average values, which are not useful for 1) making a conservative estimate of buildings’ impacts in the absence of knowing a product supplier, or  2) incentivizing individual manufacturers in investing in low-carbon technologies. There is a need for high-quality, transparent, and free impact data for high-impact building materials that captures the variation in impacts across markets regardless of availability of product-specific EPDs.

Unlike traditional LCA models which are based on averages, openIMPACT results are based on probabilistic models. The openIMPACT results capture probabilities of supply chain scenarios based on market data and dependencies of main parameters in manufacturing and supply chains. This is done by enhancing existing LCA models and using the openIMPACT Monte Carlo Algorithm which generates impacts for one realistic production (A1-A3) scenario at a time.

The openIMPACT project uses a robust methodology to estimate A1-A3 impacts, but also includes GWP estimates for other life cycle stages, like transportation to and from site, direct use-phase processes (e.g., carbonation of concrete), and end-of-life disposal.

Planned updates to the openIMPACT project will include full development of a prototype filtering app, results for additional materials and products, additional regions, additional impact categories, and uncertainty ranges across life cycle stages other than A1-A3. openIMPACT data is planned to be added to EC3 and will be accessible via the same EC3 API in the future.

How can this work be used?

  • Resultant environmental impact data and uncertainty ranges can be used in building LCA tools where North American industry estimates are needed.
  • The parameterized models can be used to compare how environmental impact results change when parameters are set to different values.
  • More broadly, the Monte Carlo methodology developed in this project can be expanded to many material and product types to better understand their environmental impact ranges in certain regional markets.

Life Cycle (A-C) Impact of Ready-Mix Concrete

General documentation

Category documentation


Supporting data


The authors gratefully acknowledge support for this project from the MKA Foundation and other funders of Building Transparency. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the funders.

We would also like to thank representatives across government agencies, academia, and industry for their technical feedback and for taking the time in helping us shape this project.

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