Guidelines Home | v3.2r02 | v3.1 | v3.0 | v2.2 | Training | Documents | Previous Versions
Guideline M.1: Life Cycle Assessment
Intent
To use life cycle analysis to quantify and minimize the environmental impact of building materials, which have significant effects on global warming, air pollution, water pollution, energy consumption, and waste.
Required Performance Criteria
Guideline M.1A applies to New Construction projects, including additions. Guidelines M.1B is required only for New Construction and Major Renovation projects that include 20,000 gsf or more of conditioned space.
- Whole-Building Life Cycle Assessment (LCA):
Demonstrate a reduction in life cycle Global Warming Potential (GWP) of the building’s construction materials through building massing, structural design, dematerialization, and alternative assembly and material selection. This credit shall be met by documenting GWP reduction using one of the three listed compliance paths and by using one of the approved whole-building LCA software tools to complete a whole-building LCA model. A whole-building LCA model representing the final design of the project is required regardless of the chosen GWP reduction compliance path.- GWP Reduction Documentation Paths:
- GWP Reduction Path 1: Whole-Building LCA Approach
This path may be used for any building scenario and will provide a basis for comparing the impact-reduction strategies with the most potential. These include whole-building strategies such as changes to the building plan to optimize shape, layout, and surface area of assemblies. Impacts from assembly and material selections may also be documented by using this path.
Following this path, use whole-building LCA models to document a 10% reduction in GWP. The basis for this reduction is a comparison between the Selected Building Design (the design of the building at the end of the CD phase, representing the final design of the building) and the Reference Building, developed by the end of the SD phase and updated as needed. There are several methods for creating the Reference Building discussed in more detail below.1 - GWP Reduction Path 2: Assembly-Level LCA Approach
This path requires the utilization of an LCA model of a representative portion of the building to document a 10% reduction in GWP. This approach is fundamentally similar to Path 1, but a smaller functional unit based on structural bays or another representative unit is modeled in lieu of the whole building. The basis for this 10% reduction is a comparison between the Selected Design – Partial (the final design of the selected structural bays) to the Reference Model – Partial, developed by the end of the SD phase and updated as needed.
This compliance path provides a basis for comparing assembly-level and material-level impact reduction strategies but cannot be used with building-level strategies such as massing and layout. Projects using this path must also complete and submit a whole-building LCA model at the completion of design. - GWP Reduction Path 3: Material-Level LCA Approach
Use the B3 LCA Material Selection Calculator to document that the building’s primary construction materials achieve an Impact Score of 1.6 or less.
This compliance path may be used when the design team is only evaluating material substitutions to reduce GWP (e.g., exchanging one type of cladding for another). It does not compare impacts of broader building-level or assembly-level impact reduction strategies. This compliance path is limited to building projects that utilize one dominant structural and enclosure type, which must make up at least 60% of the building’s structural volume and exterior surface area respectively. This compliance path is additionally limited to projects utilizing assemblies and materials that are well approximated by the assemblies and materials contained in the B3 LCA Material Selection Calculator. Projects using this path must also complete and submit a whole-building LCA model at the completion of design.
- GWP Reduction Path 1: Whole-Building LCA Approach
- Whole-Building LCA Model:
New Construction projects, including additions, that include 20,000 gsf or more of conditioned space shall submit a whole-building LCA model representing the final design of the project. This LCA building model must be completed using Approved Whole-Building LCA Software Tools. This model should be submitted at the end of the CD phase and represent the final design of the building. If Path 1, Whole-Building LCA Approach was selected to document GWP reduction, the Selected Building Design LCA model from that approach fulfills this requirement. Whole-building LCA models must follow the requirements as listed in Meeting the Guidelines: M.1A Section below.
- GWP Reduction Documentation Paths:
- Product Life-Cycle Assessments2 Use at least 5 different permanently installed products sourced from at least five different manufacturers that meet one of the disclosure criteria below:
- Product-specific declaration.
- Products with a publicly available, critically reviewed life-cycle assessment conforming to ISO 14044 that report impacts from at least cradle to gate.
- Environmental Product Declarations (EPD) which conform to ISO 14025, 14040, 14044, and EN 15804 or ISO 21930 and have at least a cradle-to-gate scope.
- Industry-wide (generic) EPD – Products with third-party certification (Type III), including external verification, in which the manufacturer is explicitly recognized as a participant by the program operator are valued as one-half (½) of a product for purposes of compliance.
- Product-specific Type III EPD – Products with third-party certification (Type III), including external verification, in which the manufacturer is explicitly recognized as the participant by the program operator are valued as one whole product for purposes of compliance.
- Product-specific declaration.
[1] This compliance path closely follows the requirements of USGBC, “Materials and Resources Credit: Building Life-Cycle Impact Reduction,” LEED Building Design and Construction v.4, with several key changes.
[2] This guideline is aligned with the International Green Construction Code and ANSI/ASHRAE/USGBC/IES Standard 189.1, “9.4.1.4 Multiple-Attribute Product Declaration or Certification,” some language also shared with LEED v.4.