Where To Go From Here

While LCAs have come a long way in harvesting and assessing extensive life-cycle data, there is more to be done in performing, fine-tuning, and presenting these analyses.

For example, Moser points out that while LCAs and EPDs are a very good way to assess a product’s sustainable attributes, they can be complicated to understand.

“Material selection has never been a quick and easy process, but with all the additional requirements, certifications, and health concerns, it is quickly becoming an almost impossible task for architects and developers to be sure they are selecting the best of the best,” agrees Ian Johnson, a green building consultant with the Cambridge, Massachusetts-based Signature Sustainability in a blog titled “Healthy Building Materials Research.”

“It seems at this point, understanding building product hazards and sustainability criteria could be a university major all in itself,” he adds.

And while the information is valuable, Bates asserts that it isn’t easy to utilize the data directly for an architectural design. “An EPD, as a standalone item, is challenging to make relevant to a particular design, much less to compare across different design options of complex assemblies, each comprising of multiple products,” he says.

Another shortcoming with LCAs is that they rely on broad assumptions about the longevity of materials and assemblies.

“Experience has shown that the longevity of any given building envelope assembly can vary widely, depending on the quality of the project-specific construction details and other factors,” explains Moser. “For example, building envelope assemblies with inferior flashing details or whose attachments are prone to corrosion, may fail, and require replacement prematurely.”

Consequently, he says that the best way to reduce environmental impacts is to design the details to promote the overall longevity of the selected roof/wall envelope assemblies and ensure that all components have compatible life expectancies.

Photo courtesy of Revere Copper Products, Inc./Anton Grassl Photography

To preserve the historical character of Boston’s Residences at 877 Beacon Street in Boston, in addition to lending durability, beauty, and flexibility around curves, copper was selected to clad the front of the building. On the back side, a coil sheet metal was used to create a dynamic facade that expresses the building’s geometry, floor levels, and to break up the massive addition. The metal panel skin introduces a subtle champagne palette to balance the neighboring red brick facades.

Designers should also be aware that a building envelope assembly’s operational energy use—and associated environmental impacts—are often not included in LCA studies and EPDs due to the difficulty in calculating this data and the fact that it can vary significantly across different building types and climates.

“This remains a challenge because accounting for building energy use requires either defining a detailed standard scenario, which will inherently not be able to represent the diversity of buildings and climates that exist, or performing a project-specific LCA,” explains Moser.

Jewell agrees, adding that LCAs and EPDs struggle to provide impact assessment results that are specific to a certain location, which is one of the reasons why LCA, by design, calculates potential environmental impacts rather than accurate predictions.

As for the harvesting of information required for an LCA, product manufacturers are forced to rely on secondary data from suppliers and other members of the life-cycle chain. Although the current LCA process is still considered one of the best ways to analyze the full life-cycle performance of a product, Jakubcin points out that the data from secondary suppliers may be outdated and could introduce some uncertainty into these studies.

Another limitation of LCAs and corresponding EPDs is that they don’t address toxicity, human health, or biodiversity very well, as these impact-assessment methods are still in their infancy, according to Jewell. And while life-cycle costing and social LCA have made great progress in recent years, the social-economic impacts related to sourcing choices have yet to be included.

Furthermore, PCRs are not yet available for all products and are often not consistent enough to guarantee comparability with other EPDs.

“PCRs fail to serve the specifier and the end user when the product category is defined too narrowly (i.e., based on a particular technology) rather being written around a generic product function,” says Moser.

At the same time, Jewell points out that synchronization efforts are underway as stakeholders are learning which constraints are most important to establish for each product type.

“Efforts to harmonize PCRs will ensure better consistency and comparability of EPDs moving forward,” agrees Jewell’s thinkstep colleague Susan Fredholm Murphy, director of consulting and innovation. “This will then enable purchasers to make more informed choices when selecting which product to buy.”

Moser also acknowledges that some program operators have standardized the “part A” of a PCR that is common to all building materials across all construction products but stressed the importance of generic PCRs, in lieu of PCRs written around a specific product, to promote consistency and more accurate comparisons between products.

The Road Ahead

The upshot is that while LCAs and EPDs are becoming continuously advanced over time, there is still a lot of room for improvement.

While today’s designers are typically looking to “check the box” with EPDs, Jewell anticipates that these expectations will change over time as the building industry matures and becomes savvier when it comes to sustainable selections.

Photo courtesy of CENTRIA

Insulated metal panels helped the new Clifford S. Bartholomew Building at William Allen High School in Allentown, Pennsylvania, achieve LEED Gold certification.

“Data and transparency are fundamental to making any kind of an informed decision about a product design, manufacturing process, or building design,” stresses Moser, and accurate, good-quality LCAs are a key part of this equation.

With the development of more sophisticated LCA data and EPDs, this will also enable LCA studies and EPDs of entire assemblies and full building analyses.

Furthermore, a greater integration of EPD data into LCA analysis tools will ultimately enable designers to understand the environmental impact of their specific material selections in real-time, says Bates.

Summing up the key role that LCAs and EPDs play in the sustainable building movement, Fredholm Murphy concludes, “As the world continues to value and promote greater transparency, LCA data will become an increasingly important tool in measuring and disclosing environmental impacts.”

The Metal Construction Association brings together a diverse industry for the purpose of expanding the use of metal in construction through marketing, research, technology, and education. MCA member companies gain tremendous benefit from association activities that focus on research, codes and standards, market development, and technical programs. www.metalconstruction.org