Standard for sustainable infrastructure promotes solutions that span life cycle

One of the newest standards by the American Society of Civil Engineers (ASCE) establishes minimum requirements for a sustainable infrastructure solution. Owners and engineers alike can use ASCE/COS 73-23: Standard Practice for Sustainable Infrastructure to set sustainability goals and assess their infrastructure projects.

Defining solutions

ASCE 73 establishes the following criteria for an infrastructure solution to be considered sustainable:

  • The solution must satisfy at least 19 out of 27 outcomes in the standard, which are under six categories:
    1. sustainability leadership
    2. quality of life
    3. resource allocation
    4. natural world
    5. greenhouse gas emissions
    6. resilience
  • Once a solution satisfies a minimum of 19 outcomes, users are instructed to perform a life-cycle cost analysis.
  • Solutions that meet the minimum of 19 outcomes and achieve the least equivalent life-cycle cost shall be defined as sustainable infrastructure solutions.

The solution must be supported by a sustainability management plan that, at minimum:

  • addresses owner, community and stakeholder needs and issues
  • establishes sustainability goals and objectives to balance the solution’s economic, environmental and social impacts (quantifiable and nonquantifiable)
  • identifies specific outcomes in each of the six categories that will yield a sustainable infrastructure solution
  • is implemented throughout the life cycle of the infrastructure solution to monitor and enhance sustainability performance. The infrastructure life cycle includes planning, design, construction, operation and maintenance and decommissioning.

Emphasis on the infrastructure life cycle

ASCE 73’s focus is clear: to develop sustainable infrastructure solutions, owners, architects, engineers and contractors must evaluate and plan each step in an infrastructure asset’s life cycle.

As an example, let’s take a closer look at one outcome from the natural world category: “Avoid, or minimize, and/or mitigate the introduction of invasive species.” It is straightforward enough to design new landscaping that excludes invasive species and includes native species. To fully integrate this outcome throughout the site’s life cycle, it becomes necessary to create a sustainability management plan that:

  • trains staff to identify and remove invasive species
  • establishes the labor force necessary to maintain the site’s native landscaping
  • creates a maintenance schedule for staff to follow
  • writes policy that lists the acceptable native plants for use on the site
  • calculates a budget that includes the labor and materials for regular native landscaping maintenance and renewal (plant death, weather events, etc.)

Ultimately, the sustainability outcomes in ASCE 73 are not complete when the infrastructure solution is constructed — they are complete when the infrastructure solution is decommissioned at the end of its useful life.

A companion to Envision

ASCE 73 was developed with the Envision v3 rating tool framework as a guide. Envision, developed by the Institute for Sustainable Infrastructure, includes 64 sustainability and resilience indicators in five categories analogous to the outcome categories in ASCE 73. Where ASCE 73 sets the minimum standard for sustainable infrastructure, Envision provides a means of recognizing achievement and innovation in sustainable and resilient infrastructure.

What’s next?

ASCE 73 is not mandatory, but ASCE is working on establishing a committee to create a mandatory standard. Committee membership is open to the public.

Contact Michelle Alvarez at to learn how Hanson can help you plan and design your next sustainable infrastructure solution.

Posted on July 16, 2024