Precast And Leed
The green building movement continues to be one of the most significant modern revolutions in the construction industry. Since 2000, the use of the LEED system, in particular, has become the gold standard for guidance on sustainable building design for construction projects in North America and beyond. The US Green Building Council declared that in the USA alone, there were a total of 3,366 new green projects and over 470 million green square feet certified in 2016 alone, with Massachusetts, Colorado, Illinois, New York and California leading the charge for sustainable projects in terms of certified square feet per capita.
As the popularity and demand for sustainable projects continues to climb, more precasters have the opportunity to contribute to green projects and in turn be exposed to innovative concepts through the LEED system. Other than the obvious benefits to the environment, precasters are able to capitalize on improved competitive advantage as well as marketability by completing LEED projects. In October 2016, LEED v4 became the key standard for the design of sustainable buildings, with an increased emphasis on energy efficiency, as well as transparency in terms of the environmental impact of material choices.
So where can precast contribute to LEED points on projects? The NPCA has published a comprehensive guide to assist precasters in focusing on the specific credits that apply. This guide can be found here:http://precast.org/wp-content/uploads/2011/03/LEED-v4-Guide-for-Precasters.pdf
Across all of the 6 major credit categories, precast can assist in several ways:
Precast is an excellent choice for environmentally sensitive locations, offering superior versatility to traditional construction, reduced spatial and site requirements and more efficient land-use due to high density and diverse construction options. One example could be the erection of a modular precast park facility which is shipped to site complete, eliminating the impact of normal construction on the environment.# of potential points contributed by use of precast – 8 out of 16 (LEED Points)
Through the use of innovative precast storm water products and multi-storey precast parking and green structures, the impacts on ecosystems and water resources can be minimized. The use of vegetated roofs and planters to reduce runoff and increase open space is a tactic that can be used. Multi storey parking also helps by increasing the area of shaded parking that would otherwise contribute to heat island effect.# of potential points contributed by use of precast – 9 out of 10 (LEED Points)
Precast excels in this credit category because of the inherent thermal mass of precast concrete compared to other types of materials such as wood. Because of this, buildings constructed with precast concrete can achieve very high levels of energy efficiency, and can therefore score high points for the energy performance credits.# of potential points contributed by use of precast – 20 out of 35 (LEED Points)
As a primary building and infrastructural material, precast concrete is exceptionally durable resulting in a low life cycle environmental impact due to reconstruction, repair and maintenance. Precast products are also recyclable and make use of recycled content through the use of fly ash, slag, recycled reinforcement and aggregates and are therefore an environmentally responsible material choice.# of potential points contributed by use of precast – 14 out of 14 (LEED Points)
Precast concrete can contribute significantly to improving the overall environmental quality within a building in three ways: Firstly, Precast floor systems allow for shallower floor plates and longer spans without columns, leading to better natural lighting and views to the outdoors. Secondly, using precast concrete as a finished material on exposed walls, floors and ceilings takes advantage of the facts that it is classified as a “non-emitting source” of volatile organic compounds (VOCs). Third, precast concrete offers excellent noise control, achieving superior sound transmission ratings to other materials.# of potential points contributed by use of precast – 8 out of 18 (LEED Points)
This credit category is where precasters can excel beyond the requirements of the other categories by bringing unique ideas and added value to the table. For example, a production method that reduces embodied carbon dioxide, or a proprietary design that reduced the amount of reinforcement required would be candidates for this category. Also, it is not widely known that USGBC also offers ‘Pilot Credits’ in their credit library which can be adopted for extra points.# of potential points contributed by use of precast – 5 additional points (LEED Points)