What Concrete Contractors Need to Know About EPDs

EPDs may be used as inputs for the evaluations conducted under rating systems like LEED and Green Globes but they are not a rating system themselves. Here's what concrete contractors should know about an EPD.

EPDs and Concrete | What Concrete Contractors Need to Know About Environmental Product Declarations
The world's first near zero-carbon 3D printed home used Eco Material's PozzoCEM Vite by automated construction company, Hive 3D in Round Top, Texas.
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As project developers and governments embrace “green” construction practices, contractors, architects, engineers, and other specifiers are using Environmental Product Declarations (EPDs) to compare materials like cement based on their environmental impacts and selecting the ones that reduce carbon emissions without sacrificing performance. An EPD is an independently verified and registered document that informs building professionals and consumers about a product’s environmental impacts based on lifecycle assessment studies. Similar to a nutrition label, EPDs provide transparency on a product’s potential impact on global warming, acidification, fossil fuel depletion, and other environmental concerns. The building and construction industry produces nearly 40 percent of global greenhouse gas (GHG) emissions, and as a result, EPDs have become key to reducing a project’s carbon footprint through procurement of low-carbon materials at the start of construction. 

It is paramount to note the difference between EPDs, which are becoming a requirement for material manufacturers, and green building rating systems such as LEED and Green Globes. While entirely voluntary, these rating systems are still expected to play a role in reducing the environmental impact resulting from construction and operation. EPDs may be used as inputs for the evaluations conducted under these rating systems, but they are not a rating system themselves. They assess product manufacturing from raw material extraction and transportation to the waste generated at the end of a product’s lifetime, and follow consensus-based standards certified by third-party experts. A published EPD is valid for a period of five years.

While EPDs are not mandated by law, they are often requested by government agencies that seek to lower the carbon footprint of construction projects. Most notably, EPDs are used for state and federal “buy clean” procurement policies in which governments purchase concrete, steel, asphalt, and glass that have lower embodied GHG emissions as indicated by their ecolabels. California, Colorado, Maryland, Massachusetts, Minnesota, New Jersey, New York, and Oregon require EPDs for public procurement.

At the federal level, the Federal Buy Clean Task Force — which includes 14 federal agencies and accounts for 90 percent of all federally purchased construction materials — provides instructions for integrating “buy clean” practices into procurement and funding processes. According to the Federal Highway Administration (FHWA), transportation agencies “are beginning to require and collect EPDs during project procurement to prepare for implementing EPDs as part of procurement decisions.” State DOT adoption and implementation of procurement using EPDs has steadily increased over the past five years. As FHWA notes: “The use of EPDs is not required under title 23, United States Code; however, the Federal government has outlined related efforts through Executive Order (EO) 14057. Under the EO, several Federal agencies are advancing activities related to EPDs.”

EPDs have already been developed for concrete, cement, and slag products. Soon construction pros can expect to see labels for supplementary cementitious materials (SCMs) such as fly ash, a popular substitute for traditional cement used in more than half of the concrete produced in the U.S. Many of the world’s most famous dams, bridges, skyscrapers, and roads have been built using high-performance fly ash concrete mixes to achieve superior strength and longevity while lowering carbon emissions.

Presently, SCM-specific EPDs are being developed with input from representatives of the American Coal Ash Association, the National Ready Mixed Concrete Association, the Portland Cement Association, and the Federal Highway Administration, among other stakeholders. The documents will cover lifecycle assessments specific to fly ash, bottom ash, harvested ash, raw natural pozzolan, calcined natural pozzolan, and alternative SCMs. Creation of EPDs are, ultimately, the responsibility of SCM ash marketers and cement and concrete producers, and they can provide a competitive advantage where project owners require transparent information about the lifecycle environmental impact of materials.

Contractors need to understand what EPDs reveal about a product. In the case of SCMs, fly ash sourced directly from a power plant essentially starts with a zero-carbon footprint. Then, any carbon inputs resulting from transportation or processing of material before reaching the loadout silo get factored in. Moreover, any carbon-generating activities — such as beneficiation — carried out by the ash purchaser after loadout also would need to be computed and published by the end user responsible for producing the EPD. The lifecycle assessment needed to produce the final EPD is performed according to ISO 14040 and 14044 requirements, and final EPD product labels are developed in accordance with ISO Standard 14025 (ISO 2006).

EPD labels don’t rank products. Instead they offer details about organizational information, the assessed product and its specifications, the declared or functional unit of assessment (e.g., m3 of the assessed product), materials incorporated in the product and their origin, and environmental emission results by lifecycle stage. Type III EPDs, which are developed for an individual product sold by a manufacturer, are best for analyzing the embodied carbon of a product. In contrast, industry-wide EPDs apply to industry averages for a product type and act as a useful benchmark.

Whether working with buildings or infrastructure, contractors can expect to see greater use of EPDs, especially in the use of concrete mixes. Project managers have the choice of substituting recycled materials — like fly ash and other coal combustion products — for conventional products to achieve sustainable design and drastically reduce a host of environmental impacts. In many cases these materials cost less, are available locally, and are technically equivalent or superior to virgin materials.

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