A sustainable rating system for horizontal infrastructure.
By Alex Morales, M. Ed.
Not too long ago, many businesses and corporations saw sustainability as a marketing tool and, when their efforts and commitment appeared disingenuous, it contributed to negative perceptions of sustainable business practices.
However, the positive impact of sustainable building practices properly employed in the design, construction and operation of buildings cannot be denied.
Leadership in Energy and Environmental Design is the most widely used green building rating system in the world and is available for virtually all buildings. Buildings achieving a LEED rating are proven to cost less to operate and attract tenants seeking to save on utility costs. The rating system focuses on vertical infrastructure and has a larger impact on more tenants and building operators as the buildings get taller. The Institute for Sustainable Infrastructure – a non-profit created by the American Council of Engineering Companies, the American Public Works Association, the American Society of Civil Engineers and the Harvard University Graduate School of Design – has a similar rating system for horizontal infrastructure, or just about everything else besides habitable buildings. The rating system is called Envision, and certifications began in 2012.
ASCE’s 2017 Infrastructure Report Card gave America’s infrastructure a D+ rating due to its aging roads, bridges, stormwater and wastewater systems, and other critical structures. According to the report, one out of every five miles of highway pavement is in poor condition. There is certainly a lot of infrastructure work needed, and federal and state governments are trying to find ways to address these needs. But, this is where precast concrete can be used to help address the infrastructure needs while adding some much needed resiliency.
In the 2015 May-June Precast Inc. article, “Codes and Standards: Heading for greener pastures,” Claude Goguen, P.E., LEED AP, NPCA’s director of outreach and technical education, introduced precasters to Envision stating, “Envision measures the sustainability of an infrastructure project from design through construction and maintenance.”
Precast concrete can contribute to a project’s Envision verification due to low site impact, speed of construction and ease of installation benefits. In an industry that is defined by its relationships with contractors, designers and even the community, the use of precast concrete in projects impacts Envision’s leadership category.
Learning from the criticisms of the LEED system, the creators of Envision ensured the program could not be used simply as a marketing tool. In fact, Envision’s sustainable infrastructure rating system has improved since its launch and now includes 64 credits to address the environmental, social and economic impacts in project design, construction and long-term operation. The credits are arranged into five categories:
1. Quality of life – This area credits a project’s impact on the surrounding community. The purpose of the project, the wellbeing of local residents and the overall preservation of historic and cultural community resources are evaluated.
2. Leadership – This area recognizes credible management and leadership regarding a project’s sustainability. It is a measure of the effectiveness of the project team’s impact on sustainability. Collaboration and teamwork, overall project management (as it pertains to sustainability) and long-term planning and maintenance are evaluated.
3. Resource allocation – This credit area measures the reduction of both embodied energy and the use of virgin materials. The three broad credit categories related to resource allocation pertain to sustainable use of materials, energy and water. Credits are earned in this category for the use of recycled materials, the reduction of energy consumption and the use of renewable energy during construction, and the protection of freshwaters surrounding the site.
4. Natural world – Strategies in this credit area relate to a project’s impact on biodiversity, including restoring disturbed soils and controlling invasive species. Siting is an important credit area in this category and measures the protection of wetlands, prime habitats, floodplain functions and more.
5. Climate and resilience – This area seeks to control emissions during construction and ensure the project’s resilience into the future. Long-term adaptability of a project is important in this area as it measures a project’s ability to be resilient to the consequences of long-term climate change or adapt to other long-term change scenarios.
A recent update, Envision v3, increases the number of available points to 1,000. Additional updates include:
- Expanded scope credits – New credits are available for life cycle economic evaluation, equity and social justice and sustainable community planning.
- New construction-focused credits – Credits added include: improve construction safety, minimize construction impacts, reduce construction waste, reduce construction energy and water use.
- Verification process pathways – Under Envision v3, a project may begin to pursue verification either after the design phase or after the construction phase. Projects that seek verification after the design phase will be subject to an additional post-construction review to validate that the commitments made during planning and design were carried through to construction.
ISI began accepting project registrations under the updated Envision v3 in July 2018. Those who had been preparing to submit registrations under Envision v2 must do so by Dec. 31, 2018. No new registrations will be accepted after that date.
A complete detail of the program’s 1,000-point system is available at sustainableinfrastructure.org.
Low Level Road Project
The first infrastructure project to receive the Envision Platinum award was the Low Level Road Project located along the North Shore of Vancouver, Canada’s Burrard Inlet. The project used precast concrete wall panels manufactured by Lafarge’s plant in Calgary, Alberta, during construction. ASCE touted the success of the project, which benefitted Port Metro Vancouver, Canadian National, TransLink, Canadian Pacific Railway and the City of Vancouver. The project improves community mobility, increases active transportation options (including rail), and mitigates threats from slopes and seismic events.
West Park Equalization Facility
A U.S. project that used precast concrete and received the Envision Platinum award is the Nashville Government West Park Equalization Facility.
The project involved installing a 260-foot diameter, 37-foot-high wet weather storage tank, which is one of the largest closed-dome, prestressed concrete equalization tanks in the U.S. The storage tank is used for sewer overflow when the current pump station reaches capacity, reducing sanitary sewer overflows. The project’s success was due to relocating the proposed location of the tank to a park closer to the pump station. The savings gained from the relocation were put back into the community to improve the park, adding softball fields, a basketball court, walking trails and improving the quality of life in the area.
Envision positively impacts all involved
The Envision program applies as much to the contractor and owner as it does to the community and environment. Moreover, it’s not specific to vertical construction. It expands the concept of sustainability to all infrastructure and inherently addresses the issue of greenwashing by forming collaborative relationships between builders, city planners, environmentalists, subcontractors and the community at large. The program is robust and comprehensive, and precast concrete plays into Envision certifications in positive ways.
Alex Morales, M. Ed., is NPCA’s director of workforce development.
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