By Claude Goguen, P.E., LEED AP
Precast concrete contributions raised in LEED v4.
When LEED v1 launched in August 1998, few predicted its longevity. But 18 years later, the fourth version of this popular rating system has been released. As the clock strikes twelve on Halloween night later this year, the bell will toll for LEED v3, along with Materials and Resources credit 4: Recycled Content and credit 5: Regional Materials. These credits were low-hanging fruit for the precast industry, as most precasters use recycled materials in their concrete such as rebar or fly ash, and most are located within 500 miles of raw material suppliers and on-site projects. The bar has now been raised in LEED v4; however, precast concrete can still contribute. Knowing how can help manufacturers properly position themselves in the growing LEED market.
Why is this important?
In the U.S., 38% of all carbon dioxide emissions, 13.6% of potable water use and 73% of electricity consumption is attributed to buildings.1 This is what prompted the United States Green Building Council to create the Leadership in Energy and Environmental Design program. The program is an independent, third-party verification rating system that provides a measuring stick for environmental design and occupancy comfort and health. It is the most widely used green building rating system in the world, with 1.85 million square feet of construction space certified every day. Developers and owners seeking LEED certification for their buildings depend on their contractors and suppliers to reach this achievement. Precast manufacturers that can readily provide information on how their products contribute to the new LEED v4 system have a significant edge on the competition.
How has LEED changed?
The LEED v4 rating system differs from its predecessor because it has five rating systems:
- BD+C – LEED for Building Design and Construction
- Homes – LEED for Homes Design and Construction
- O+M – LEED for Building Operations and Maintenance
- ID+C – LEED for Interior Design and Construction
- ND – LEED for Neighborhood Development
The one that applies most to precast concrete is BD+C, although precast can also help in other systems. Within BD+C, there are eight categories ranging from new construction to schools and warehouses. The rating system has six main credit categories and three additional categories in order get a maximum of 110 points. The certification levels are as follows:
- Certified: 40 to 49 points
- Silver: 50 to 59 points
- Gold: 60 to 79 points
- Platinum: 80 to 110 points
Where can precast contribute?
There are many areas within the LEED v4 rating system where precast concrete can contribute directly or indirectly to earning credits. For a complete list of potential precast contributions, visit precast.org/sustainability. Here are four categories where precasters can help designers earn LEED credits.
- Building product disclosure and optimization – environmental product declarations
This credit encourages the use of materials that have life cycle information available and preferable life cycle impacts. Thanks to the recently released product-specific environmental product declarations, precast concrete has that information.2
- Building product disclosure and optimization – sourcing of raw materials
Option 2 – Leadership Extraction Practices awards 1 point if 25%, by cost, of all products in the building meet at least one of the responsible extraction criteria. Several pathways are provided for meeting this option, including responsible forestry and material reuse and recycling. Precast concrete products can contribute to the recycling portion since most concrete contains recycled materials such as fly ash, slag and reinforcement.
- Minimum energy performance
This is a prerequisite and is intended to help reduce the environmental impacts of excessive energy use. The first option requires demonstrating an energy performance improvement of 5% for new construction compared with the baseline building performance. Energy performance must be measured by a whole building simulation using ANSI/ASHRAE/IESNA Standard 90.1–2010, Appendix G. Many building simulation programs are available to demonstrate performance based on materials used and design. Buildings constructed of precast concrete benefit from thermal mass, which helps moderate indoor temperature extremes and reduces peak heating and cooling loads. In many climates, these buildings have lower energy consumption than buildings made with walls of similar insulation and lower thermal mass properties. In addition, heating, ventilation and air-conditioning needs can be met with smaller-capacity equipment.3
- Low-emitting materials
The intent of this 3-point credit is to reduce concentrations of chemical contaminants that can damage air quality, human health, productivity and the environment. The focus is to remove volatile organic compound emissions from indoor air and materials in ceilings, walls and floors. Many interior finishes, such as paints, coatings, adhesives and sealants have significant emissions. In many applications, exposed precast concrete serves as both the structural element and the finish material, eliminating the need for additional interior material to be applied. LEED v4 defines precast concrete as an “inherently non-emitting source” of VOCs.
Precast concrete – a valuable asset
These are just a few examples of how precast concrete is a valuable asset to a builder seeking LEED v4 certification. Precasters need to familiarize themselves with all potential contributions their product lines offer. Next, this information should be displayed on your company’s website to attract contractors on LEED projects. For help or guidance, contact National Precast Concrete Association and the NPCA Sustainability Committee. The committee is working hard to decipher and simplify programs like LEED v4 to demonstrate to producer and associate members how to be an active player in the LEED rating arena.
For more information on this topic or any other sustainability-related topics, please contact Claude Goguen, P.E., LEED AP, director of sustainability and technical education, at [email protected] or (317) 571-9500.
Claude Goguen, P.E., LEED AP, is NPCA’s director of sustainability and technical education.
1 United States Green Building Council – This is LEED, precast.org/leed
2 See precast.org/force-awakens for more EPD information
3 For more information on thermal mass of concrete, visit precast.org/thermal-mass