FRAMEWORK

EMBODIED CARBON: CARBON SMART MATERIALS

Achieving zero emissions from new construction will require low-carbon and carbon-positive building materials that sequester carbon where possible.

The embodied carbon of the building materials for the structure and enclosure, and construction, represents 11% of total annual global GHG emissions. When interior walls, finishes, fixtures, equipment, mechanical, plumbing and electrical systems, and site infrastructure are taken into account, the percentage of global GHG emissions is much greater.

Addressing embodied carbon emissions begins with building and infrastructure design and material specifications, leading to policies for low- to carbon-positive building materials. 

Prescriptive and Performance Specifications and Policies

Prescriptive and Performance measures are being developed and incorporated in both government policies, and in the design of buildings, infrastructure and the specifications of materials and systems. Prescriptive measures for reducing embodied carbon identify the attributes of infrastructure, buildings, and materials that result in lower embodied carbon emissions, while performance measures set maximum embodied carbon emission (Global Warming Potential) thresholds for each. Providing designers and builders with multiple pathways for reducing embodied carbon will facilitate more immediate and wide-spread emissions reduction adoptions.

Prescriptive Path:

  • Identifies infrastructure, buildings, and materials that have the highest embodied carbon impacts (e.g. concrete and steel) and then establishes sets of attributes that result in embodied carbon reductions.
  • Integrates these sets of attribute into building design specifications, building construction, and government policy and procurement language.

Performance Path:

  • Identifies infrastructure, buildings, and materials that have the highest embodied carbon impacts and then determines the maximum global warming potential (GWP) thresholds for each.
  • Integrates GWP thresholds for product categories into building design specifications, building construction, and government policy and procurement language.

Achieving Zero embodied carbon emissions will come from Prescriptive Path and Performance Path approaches to policy:

Achieving Prescriptive Specifications for Embodied Carbon

Prescriptive specifications for reducing embodied carbon identify attributes of building materials and systems that result in lower emissions.

The immediate creation and adoption of prescriptive embodied carbon specifications and policies are critical to meeting global climate targets. To create prescriptive specifications, first identify materials and systems that have the highest embodied carbon impacts (e.g. concrete, steel, insulation, glass, etc.) and then identify sets of attributes that result in reducing their embodied carbon. These attributes are then integrated into product specifications to create government policies and procurement language.

Highlighted Policy: Carbon Smart Materials Policy Toolkit

To support the development of immediately adoptable prescriptive embodied carbon policies, Architecture 2030 launched the Carbon Smart Materials Palette. The Palette identifies high-impact building materials, the attributes that contribute to their carbon footprint, and provides strategies for reducing their emissions.

These attributes and strategies (e.g. recycled content, biogenic materials, carbon-free renewable energy supply, low/zero-carbon manufacturing processes, reduced transportation, existing building reuse and repurpose) will result in a toolkit of prescriptive standards that can produce low-carbon or carbon-positive products and systems, and buildings as carbon sinks. These attributes and strategies will be integrated into model policy and specification language and included in the Carbon Smart Materials Policy Toolkit, which will be released in 2019.

Why this Strategy?

The Carbon Smart Materials Policy Toolkit will:

  • Be immediately actionable
  • Be high-impact and scalable
  • Give designers control over embodied carbon impact
  • Advance the market to meet new low-carbon or carbon-positive demands
  • Support the continued development of Environmental Product Declarations (EPDs)

A Performance Path to Embodied Carbon Emissions Reductions

Performance policies and specifications set a maximum embodied carbon emissions (Global Warming Potential) threshold for each material/system.

In order to promote reducing construction materials emissions and foster innovation, many jurisdictions are taking a performance policy approach to embodied carbon reductions. A number of cities and states are requiring manufacturers to provide Environmental Product Declarations (EPDs) in order to establish emissions baselines or average global warming potentials (GWPs) for each product category, and then require GWP reductions from the baselines. These GWP thresholds are then reduced over time to reflect embodied carbon improvements in the design of buildings and production of materials. 

In order to achieve zero embodied carbon emissions by 2050, Architecture 2030 recommends that these reductions align with the 2030 Challenge for Products, which asks the global architecture and building community to adopt the following targets:

Products for new buildings, developments, and renovations shall immediately be specified to meet a maximum global warming potential (GWP) of 35% below the product category average. The GWP reduction shall be increased to:

  • 40% or better in 2020
  • 45% of better in 2025
  • 50% or better in 2030
  • ZERO by 2050

Highlighted Policy: Buy Clean California

The Buy Clean California Act requires state agencies to consider the embodied carbon emissions of industrial products (steel, rebar, glass, and mineral wool board insulation), when contracting for state-funded projects. The Act requires contractors who bid on state infrastructure projects to disclose the GHG emissions data for certain materials they intend to use.

As a result, manufacturers must create facility-specific EPDs. The department will then use the EPDs to establish a maximum acceptable global warming potential for each category of eligible materials.

Policy Precedents: Embodied Carbon

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