By Claude Goguen, P.E., LEED AP
Chances are if you haven’t worked on a LEED project recently, you will. Since its unveiling in 2000, Leadership in Energy and Environmental Design (LEED) has become a part of building construction vernacular in North America and around the world.
From its humble beginnings, LEED has grown to the point that it is now certifying 1.5 million sq ft of building space each day in 135 countries. Today, more than 54,000 projects are currently participating in the current version, LEED 2009, comprising more than 10.1 billion sq ft of construction space. Some owners and specifiers have embraced it while others find flaws in this rating system, but love or hate it, it continues to grow.
As a part of that growth, the U.S. Green Building Council (USGBC) is currently launching LEED v4. After a couple of years of deadline extensions and six public comment periods, 86% of USGBC members voted to approve this latest version.
The USGBC is taking a phased approach to LEED v4. This means that rather than requiring all projects to use it right away, it is giving the marketplace time to become familiar with the concepts and theories that it’s based on. Project teams can register their projects under LEED 2009 until June 1, 2015.
Practitioners familiar with previous versions of LEED will recognize the same fundamental structure. There are still prerequisites and credits, 100 base points, regional priority credits and pilot credits. v4 has more emphasis on USGBC’s goal of reducing carbon emissions, and this means increased energy efficiencies across the board. Consequently, v4 had adopted ASHRAE standards.
LEED v4 is technically more rigorous than its predecessor. This version also expands the market sectors (21) able to use LEED including data centers, warehouses and distribution centers, hospitality, existing schools, existing retail, and LEED for Homes Mid-Rise.
Credit weightings have also been revised. Point distribution will more closely tie the rating system requirements to the priorities articulated by the USGBC community.
There are new prerequisites and credits across the LEED credit categories and rating systems. Point values have also changed. Each rating system has gone through a weighting process and has LEED points associated with each credit and option of the rating system.
How does LEED v4 affect the use of precast concrete?
Some of the changes affecting the use of precast concrete include:
- Site Development – Protect or Restore Habitat (formerly SS 5.1): The requirement is to preserve and protect from all development and construction activity 40% of the green field area on the site (if such areas exist). Precast will still contribute in this category because it’s made to order, reduces storage space on site and minimizes site disturbance.
- Rainwater Management (combined former 6.1, “Stormwater Design – Quality Control,” and 6.2, “Stormwater Design – Quantity Control”): Precast will still contribute through the use of stormwater products to manage the runoff.
- Heat Island Reduction: Precast concrete has a higher solar reflectance than many other materials, which is beneficial in reducing the heat island effect.
- Building Product Disclosure and Optimization – Environmental Product Declarations: Multi-Attribute Optimization – This credit rewards the use of products that comply with one of a few criteria including products sourced (extracted, manufactured, purchased) within 100 miles of the project site. Precast concrete manufacturers are often located within short distances from the project.
- Building Product Disclosure and Optimization – Sourcing of Raw Materials: Leadership Extraction Practices – This credit awards points based on the use of products that meet at least one of six responsible extraction criteria for at least 25%, by cost, of the total value of permanently installed building products in the project including recycled content. Precast concrete includes pre- and post-consumer recycled content mostly through the use of supplementary cementitious materials and reinforcing.
- Construction and Demolition Waste Management: Reduction of Total Waste Material – Do not generate more than 2.5 lbs/sq ft of construction waste on the building’s floor area. The use of precast concrete significantly reduces construction waste, because it arrives on site ready to be installed.
- Regional Materials: The “regional” definition will no longer be 500 miles. It is currently based on “Regional Core Based Statistical Area,” updated Dec. 1, 2009, by the U.S. Office of Management and Budget.
- Thermal Comfort (renamed from “Controllability of Systems – Thermal Comfort,” combined with “Thermal Comfort – Design Requirements for Achievement”): Design of heating, ventilation and air conditioning (HVAC) systems and the building envelope will need to meet the requirements of ASHRAE Standard 55-2010, “Thermal Comfort Conditions for Human Occupancy.”
- Precast Enclosures: Precast enclosures will contribute due to concrete’s thermal mass properties.
Environmental Product Declarations
LEED v4 also awards credits for the use of Environmental Product Declarations (EPDs) for products and Life Cycle Assessments (LCAs) for whole buildings as a way to demonstrate transparency and superior environmental performance. Similar to a food nutrition label, an EPD reports environmental impacts such as carbon footprint, acidification or ozone depletion potential. EPDs list quantified life-cycle product data and are owned by the product or brand producer. In essence, they are eco-labels, and many believe they will be required for all building products in the future.
Product Category Rules (PCRs) govern how LCAs and EPDs are written. The PCR is developed for a broad product type such as vinyl siding, asphalt roof shingles and precast concrete. NPCA is working with other industry partners to create a North American PCR for precast concrete.
LEED could be an opportunity
The green building industry is continuing to grow, and LEED has been a big part of that growth. Expand your market by educating yourself on the LEED program. Request information from your suppliers in regard to recycled content and any other documentation that may assist your customers in pursuing LEED credits under the 2009 version or the new v4 version.
For more help with understanding LEED and what you need to supply to your customers, visit NPCA’s website at precast.org/sustainability.
For questions about this article, please contact Claude Goguen, NPCA’s director of Sustainability and Technical Education, at (317) 571-9500 or [email protected].