by Ben Mitchell and Vikas Ahuja
It is incumbent on designers and specifiers to develop an increasingly sophisticated understanding of how various products and materials impact the environment. General terms such as ‘green’ and ‘sustainable’ are giving way to ISO-guided, science-based, standardized measures of products’ and buildings’ environmental performance. Fortunately, assessment tools and methodologies are making these measures easier to access and understand.
To designers and specifiers, the most familiar of these tools is the Environmental Product Declaration (EPD). Produced by manufacturers, but verified by independent third parties, these provide quantified environmental data. An EPD can be done by an individual manufacturer (known as a ‘product-specific EPD’) or an entire industry (known as an ‘industry-average EPD’). When using the U.S. Green Building Council’s (USGBC’s) Leadership in Energy and Environmental Design (LEED) system, the maximum credit contribution is via the product-specific EPD route. However, industry-average EPDs can contribute toward LEED Material Resources (MR) credits.
These include Building Product Disclosure and Optimization– Environmental Product Declarations, which awards one point for using at least 20 different permanently installed products sourced from at least five different manufacturers that have used a form of life cycle analysis (LCA). A building product with a product-specific EPD counts as one whole product, whereas one with an industry-average EPD counts as half a product. A second point contribution can be possible when a manufacturer can demonstrate optimization (i.e. by using an EPD to show impact reduction below an industry average).
Many designers are also familiar with product category rules (PCRs), which are foundational to EPDs and set parameters for data collection and reporting, as well as for the type of information used in EPDs. PCRs are consensus-based documents developed by stakeholder organizations, defined in ISO 14025, Environmental Labels and Declarations–Type III Environmental Declarations, as “a set of specific rules, requirements, and guidelines for developing Type III environmental declarations for one or more product categories.” There must always be a PCR before a manufacturer can produce an EPD.
Life cycle analysis describes the process by which the parameters set forth in PCRs can be used to compile and evaluate inputs, outputs, and the potential environmental impacts of a product, system, or even a whole building throughout its life cycle. EPDs contain a summary, or selected results, of an LCA. They communicate information about the life cycle environmental impact of individual products, and can include additional environmental information, as relevant.
To develop an EPD, an LCA practitioner or consultant typically:
- identifies the correct PCR;
- collects inputs and outputs;
- uses software for LCA modeling; and
- creates EPD documentation.
Upstream data from relevant databases supplements data and assists with the assessment.
How LCA affects both design
Incentives for owners and designers to choose environmentally preferable products—and consider LCA results—have increased with the introduction of LEED v4 Building Product Disclosure and Optimization credits. Points are awarded for EPDs, as well as the sourcing of raw materials and ingredients.
Some design professionals believe once an EPD is in hand, adequate information is contained therein and no further research is necessary. However, it is important to become familiar with PCRs and LCAs as well as EPDs, as a means of verifying individual EPDs comply with methodological prerequisites. Care must also be exercised in comparing one manufacturer’s EPD to that of another. The only way two EPDs can be compared is if the PCR is the same, the product function is identical, and the software and underlying data used to do the LCA are the same in both cases.
Conversations about environmental impact center on carbon emissions, or ‘carbon footprint,’ even though this is often just one aspect of environmental impact. Product, system, and building life cycles can touch on a vast number of processes, so it is useful to set system boundaries clarifying just what is included in a given assessment. ISO 14044, Environmental Management–Life Cycle Assessment–Requirements and Guidelines, allows LCA practitioners to consider any boundary, including or excluding any process, as long as that boundary is disclosed.
This makes sense for manufacturers of products that can have a wide variety of applications once they leave the plant gate—hence the nomenclature ‘cradle-to-gate’ for an LCA that does not consider installation and use phases. However, building designers generally need to be concerned with cradle-to-grave LCAs, which include use phase and end-of-life considerations. In this scenario, the impacts of the use phase dominate most other life cycle stages.
The extensive amount of comparisons that need to be made when benchmarking environmental impacts from cradle to grave means useful tools for designers include LCA databases. These can perform whole-building LCAs throughout the design process, in real time. They are populated with industry-average life cycle impacts and product-specific EPDs, making design scenario comparisons fast, flexible, and easy.