The U.S. Green Building Council points to transparency as a guiding principle of the Leadership in Energy and Environmental Design rating program’s latest version. Unveiled at the 2013 Greenbuild International Conference and Expo last month in Philadelphia, LEED v4 responds to the increasing recognition of life cycle energy consumption by addressing buildings’ operating phases, but keeps provisions where concrete can contribute to credits on a scorecard for Certified, Silver, Gold and Platinum level certification.
USGBC presents the critical LEED v4 Materials & Resources section as pushing “forward a paradigm shift in how we think about materials. Life cycle assessment, environmental product declarations, and material ingredient reporting bring transparency to the manufacturing and decision-making process behind building materials. Using these mechanisms to make data-driven decisions is absolutely essential to building performance and human health.”
In the LEED standard of most consequence to cast-in-place and manufactured-concrete, New Construction and Major Renovations (v4), provisions are contained in Materials & Resources and Sustainable Sites sections. They raise prospects for mixes containing recycled materials; specifying pervious concrete or permeable pavers for on site storm water management; or, limiting heat island effect with conventional flatwork.
More notably, LEED v4 Materials & Resources section includes credit-driven incentives for suppliers and manufacturers to offer environmental product declarations (EPD), third party-certified documents that mimic food nutrition labels. In prior versions’ Materials sections, “We thought of attributes like recycled content. Now we want designers to think more like they are shopping [when specifying] and make trade offs,” USGBC Senior Vice President, LEED Scot Horst said at a rating program overview in Philadelphia. LEED v4’s EPD incentives will help the Council establish infrastructure for users to make decisions on material and product contents, he added.
That infrastructure hinges on significant research and certification investment by cement and concrete interests, and their peers across the building and construction supply chain. As we noted in May, the first mover anticipating the EPD advent—and certain customers eventually treating the documents as price of entry for contract consideration—is U.S. Concrete’s California business, Central Concrete Supply. The producer issued the first EPD in North America covering any concrete product. Its document spans nearly 1,500 mixes offered at San Jose headquarters and seven other northern California plants.
Central Concrete’s EPD preparation was also an early indicator of the complexity LEED v4 could bring to material and product suppliers adhering to USGBC’s brand of transparency. The producer prepared the document at the individual mix level instead of covering a class of concretes. Timely generation of documents spanning 1,479 mix designs was credited to a method devised by Climate Earth, Central Concrete’s sustainability-minded information technology services provider. The method allowed the National Ready Mixed Concrete Association, serving in the audit function as an EPD Program Operator, to verify the entire mix library.
Climate Earth performed similar duties for another key California operator, Angelus Block Co. The producer announced in mid-November the first EPD covering concrete masonry produced in the U.S. The document spans a set of 69 individual mix designs for products from each of seven Angelus Block operations serving Central Coast to San Diego markets.
The Angelus and Central EPD meet International Organisation for Standardization guidelines, which in turn require the use of consensus-developed Product Category Rules. The PCR backing early concrete EPD were written by the University of Washington/College of Built Environment-hosted Carbon Leadership Forum. LEED v4’s launch elevates complications, challenges and opportunities that Forum members sensed as they braced for next phase of green building evolution.