By emphasizing embodied carbon, is the industry in danger of focusing on one environmental aspect to the detriment of others?
That may be the case in the near term. There’s an urgency in the design community about reducing greenhouse gases emitted between now and 2030. However, we need to be careful about burden shifting. Choosing a lower embodied carbon material now that increases operating emissions in the long run is not the best solution. Other environmental impacts influence human health in the near term, such as smog creation and degradation of the ozone layer.
LCA is increasingly being used as a tool by the building industry to assess the global warming potential [GWP] of building activities. To avoid this burden shifting, analyses should consider multiple environmental impacts, but that is not standard practice.
While some building materials may look favorable in the short term, precast concrete is often built to last longer than others. How do you include that in an EPD?
Materials with lesser environmental impacts on a cradle-to-gate basis, but with much shorter service lives, can appear favorable by disregarding the impact of maintenance and replacement. That is why any comparison needs to take place in the context of the full life of the building. Right now it is difficult to capture that information, since it is not easy to create an EPD for products for every project and every usage. The best we can do is perform a full LCA of a building.
Will EPDs have an impact on building codes like the International Green Construction Code?
Definitely. Green building codes and standards are evolving as specifiers become more sophisticated in their knowledge of EPDs and as tools become available to allow for generation of more product- and plant-specific EPDs. We are still very much in the product-transparency and knowledge-gathering phase of using EPDs effectively.
Codes and standards go through a deliberate public review process. How is some of this new legislation different?
There could be legal and financial implications with some of these seemingly arbitrary benchmarks that have a narrow focus on GWP. In several states, cradle-to-gate-based requirements or upper limits on GWP are being incorporated into building regulations. Much of the new “Buy Clean” legislation has skipped the transparency and local-EPD-gathering phase and has jumped straight to setting benchmarks for certain materials based on national industry-average EPD values. This creates a patchwork of requirements across the country, and isn’t the best way to reduce environmental impact locally. The fuels used in the local utility grid greatly influence a product, system, or building environmental impact. National industry-average benchmark values may be easy for manufacturers to meet in a region that has a “cleaner” local grid, and impossible to meet in a location that has a “dirty” grid. It is better to survey what is possible in a locality and make improvements from there. Procedures to create meaningful benchmarks for products and carbon budgets for building are being developed in green building codes and standards committees, but this thoughtful process takes time.
Are tools becoming available to make EPDs easier to use?
Architects can compare the environmental performance of different building designs with various tools that incorporate EPDs or LCAs. The LCA process is complex, but these are the best tools available at this time. Those on the leading edge are utilizing a plug-in to BIM [building information modeling] that allows real-time updates to environmental impacts during the design stage to evaluate options. Eventually, the hope is that we will be able to develop LCAs for each structure or EPDs for each application of a product in a structure.
What is the rush to establish benchmarks?
Things are moving quickly to prepare for the federally funded infrastructure work in the pipeline. Agencies are looking to EPDs and setting limits in an effort to build toward a more-resilient and zero-carbon future. But some of the guidance or model code language doesn’t conform to the requirements in the ISO standards related to comparisons. Some agencies have established environmental benchmarks that don’t correlate to current construction methods. Others are based on best practices for buildings including energy performance and construction types. This scattered approach has led to a large number of benchmarking limits with varying impacts to be considered, which makes it difficult for designers and product manufacturers to comply.
The white paper entitled “Suitability of Environmental Product Declarations (EPD) in Material Selection” is available here.
PCI committee members and staff involved in producing this white paper are: Jared Brewe, PE, PCI; Harry Gleich, PE, Metromont Corporation; Corey Greika, PE, Coreslab Structures (Indianapolis); Becky King, PCI; John Lawler, PE, Wiss Janney Elstner; Ruth Lehmann, PE, PCI West; Jane Martin, GATE Precast; and Larbi Sennour, PE, CEG International.
Emily Lorenz, PE, is an independent consultant in the areas of LCA, EPDs, PCRs, green building, and sustainability. Lorenz specializes in building code and standards work and advocacy. She participates as a voting member on several committees including the 2024 International Energy Conservation Code Commercial Committee, the ASTM International Committee E60 on Sustainability, and the American Concrete Institute’s building code subcommittee on sustainability. She also serves as an expert to the ISO Working Group on Environmental Declarations of Products, and as a voting member of the Envelope Subcommittee of ASHRAE 90.1.