Institute for Sustainable Infrastructure (ISI) Envision, Version 3



Envision was first developed and published by the Zofnass Program for Sustainable Infrastructure at the Harvard University Graduate School of Design and the Institute for Sustainable Infrastructure (ISI) in 2012. Envision‘s purpose was to provide owners, engineers, and other infrastructure stakeholders the framework to deliver sustainable and resilient infrastructure through non-prescriptive requirements. The type of infrastructure projects that can pursue a rating from Envision are listed in Figure 1. Envision consists of 64 credits with a total of 1,000 points organized under five categories: quality of life, leadership, resource allocation, natural world, and climate & resilience.

Summary of Credits Related to Embodied Carbon for Structural Engineers in ISI Envision – Version 3
Credit(s) Credit Title Credit Required or Optional Achievable Points Probability of Embodied Carbon Reduction
RA1.2 Use Recycled Materials Optional Up to 16 Points Almost certainly for reused materials, usually for recycled-content materials
CR1.1 Reduce Net Embodied Carbon Optional Up to 20 Points Definitely

Credit RA1.2: Use Recycled Materials: Pursuit of this credit can award a team up to 16 points depending on the percentage of project materials that are reused or recycled. Structural engineers can help the project team receive points and reduce the structural system’s embodied carbon by using materials with high recycled content or reusing structural systems. Some structural materials have optimized the amount of recycled content due to resource availability, manufacturing process, embodied carbon reduction, and consumer demands. Engineers should confirm that any specified recycled content materials have reduced embodied carbon, since using high recycled content materials may not necessarily reduce embodied carbon relative to standard practice. Reusing existing structural materials on a project can help reduce the demand for new materials and will typically reduce the structure’s embodied carbon since extraction and manufacturing are not needed. Structural engineers will need to assess and determine the condition and strength of existing structural elements to ensure they will be adequate for the proposed design requirements. It is paramount that structural engineers are engaged during schematic design when building and material reuse is a design option.

Credit CR1.1: Reduce Net Embodied Carbon: This credit requires the project team to reduce the upfront carbon of the primary materials used on the project during construction and operation. Structural engineers play a crucial role in helping the project team reduce the embodied carbon of the infrastructure’s structural components. The certification will award the team five points for a five percent reduction of embodied carbon compared to a baseline. The points step up as a larger amount of embodied carbon is reduced. Up to 20 points will be awarded if the team achieves a 50% embodied carbon reduction compared to the baseline. In Envision, a baseline is defined as conventional performance or “business as usual.” Due to the broad applicability of types, sizes, and locations of infrastructure projects, appropriate and applicable baselines must be determined by the project team. Envision provides four acceptable ways of defining a baseline, in order of preference:

  1. Existing conditions or the existing system(s) the project will replace
  2. A seriously considered project alternative
  3. Industry “standard practice” or existing codes, standards, or regulatory requirements
  4. A project of similar scope and size operating within the same geographic area or a geographic area with similar operating conditions.

Early in the design phase, the design team should agree on which consultant should include the life cycle assessment (LCA) for the baseline in their scope. Engineers will need to utilize embodied carbon reduction strategies and technologies in addition to measuring the structural embodied carbon through an LCA tool. By measuring and utilizing reduction strategies, the embodied carbon footprint can be reduced to the greatest extent possible.

Institute for Sustainable Infrastructure (ISI). (2018). Envision, Version 3. Washington, DC. Accessed June 30, 2021. 

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