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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

Guidelines apply to all projects designated New Buildings and for Major Renovations. M1A is not required for renovation buildings or portions of buildings. M1A is required for all additions over 20,000 square feet and additions that are greater than or equal to 20% of a preexisting building’s floor area.

  1. 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.

    1. GWP Reduction Documentation Paths:
      1. 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
      2. 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.
      3. 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.
    2. Whole-Building LCA Model:
      This LCA building model must be completed using one of Approved Whole-Building LCA Software Tools. It 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.
  2. 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:
    1. Product-specific declaration.
      1. Products with a publicly available, critically reviewed life-cycle assessment conforming to ISO 14044 that report impacts from at least cradle to gate.
    2. 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.
      1. 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.
      2. 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.

[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.

Approved Whole-Building LCA Software Tools

  • Tally
  • Athena Impact Estimator
  • One Click LCA
  • For other methods, please contact guidelines@b3mn.org to request evaluation of additional methods of whole-building LCA evaluation. This list will be updated if other methods are approved.

Allowable GWP Impact Reduction Strategies by Path.

The strategies that can be used to reduce environmental impacts vary by path; below is a summary of the options available under the three compliance paths:

Path 1 Path 2 Path 3
Impact Reduction Strategies Whole-Building Assembly Level Material Level
Building size (floor area) no no no
Building service life no no no
Building shape (layout, surface area) yes no no
Building structural spacing (grid layout) yes no no
Assembly substitutions (swap types) yes yes no
Assembly design changes (thicknesses and layers of materials) yes yes no
Window-to-wall area ratio changes yes yes no
Floor-to-floor height changes yes yes no
Structure design changes (type and sizing of beams + columns) yes yes no
Material substitutions yes yes yes

Whole-Building LCA Model Requirements:

Requirements of the whole-building LCA model:[1]

[1] These whole-building LCA requirements are aligned in part on USGBC, “Materials and Resources Credit: Building Life-Cycle Impact Reduction,” LEED Building Design and Construction v.4, with some changes noted.

  1. Building service life shall be 60 years.
  2. The scope of the assessment must include EN15978 Phases A1–A5, B1–B5, and C1–C4 (cradle to grave) but omit phase D (beyond building life). Building operational energy and water use (Phases B6, B7) are not included for this requirement though both the Selected Building Design and the Reference Building must meet current B3 and SB 2030 requirements.
  3. The LCA models must include the complete building enclosure from the interior to the exterior layer, structural elements (posts, beams, bearing walls), including the intermediate floors and foundation and any attached parking structures.
  4. All interior finishes shall be omitted with the exception of those on exterior above and below grade walls.
  5. The LCA models should omit electrical and mechanical equipment including elevators, pipes, plumbing fixtures, and control systems, as well as items exterior to the building such as landscaping and surface parking lots.
  6. The Selected Building Design and Reference Building must be functionally equivalent. They must serve the same program, same gross floor area, and the same operational energy and water efficiency. The operational energy and water use for both the Selected Building Design and the Reference Building must meet current B3/SB 2030 requirements.[1][1] Differs from LEED v.4 credit: Interior non-structural walls and assemblies should be omitted from the LCA models.

GWP Reduction Documentation Options:

Documenting a 10% GWP reduction for a building’s construction materials often requires early-phase design changes, which necessitate a start to LCA evaluation in the schematic design phase. Substantial changes to a building’s structure, envelope, or building plan may be necessary. This often requires coordination between multiple team members – architects, structural engineers, and building owners.

GWP Reduction Path 1 – Whole-Building LCA Approach[1]

[1] Differs from LEED v.4 credit: for compliance with this requirement (M.1a), a 10% reduction is required for GWP only. Impacts in other environmental indicator categories such as eutrophication potential and acidification potential should be monitored, but performance improvements are not required in those areas. Compliance options 1, 2, and 3 of USGBC, “Materials and Resources Credit: Building Life-Cycle Impact Reduction,” LEED Building Design and Construction v.4 will not be considered as compliance paths for this credit.

Defining the Reference Building:
The Reference Building LCA model should be completed early in the SD phase so it can be used as a benchmark for comparing design cases and gauging GWP reductions. For Path 1, the total area of exterior walls, floors, and roofs may differ between the Reference Building and the design cases to account for optimization in building shape, layout, and surface area. The Reference Building and Selected Building Design must remain functionally equivalent, with equal floor area and space use types. Water and energy consumption must be approximately equal and meet current SB 2030 standards.

There are a variety of valid approaches for defining the Reference Building.[1][1] Reference Building options and descriptions follow LEED v.4 credit requirements.

The design team performing the LCA analysis may choose from the following options to best meet their needs:

  1. Early design case – an early design for the building under study.
  2. Existing building – a real-world benchmark, modified to match the floor area and energy efficiency of the project.
  3. Building archetype – a design similar to an existing building modified to match the floor area and energy efficiency of the project.
  4. Alternative design – a design based on the project design but that is more reflective of industry-standard materials and practices.

GWP Reduction Path 2 – Assembly-Level LCA Approach

The functional unit used in this path to document GWP reduction is a representative slice through the building incorporating the most common construction assemblies. It must extend from exterior wall to the opposite exterior wall and from the foundation to the roof. For buildings with structural bays this should incorporate at least two bays. For buildings without structural bays, project teams should contact B3 Guidelines Support to ask for guidance on selecting and sizing an appropriate functional unit for modeling. All applicable whole-building LCA modeling requirements (as listed in Meeting the Guidelines Part 1a–g) should be applied to the LCA models.

GWP Reduction Path 3 – Material-Level LCA Approach

To use this path, the building design and design team must comply with the following requirements.

  1. The project must have one dominant structural and enclosure type, comprising at least 60% of the building’s structural volume and exterior surface area respectively.
  2. This method only documents GWP reductions from material substitutions.
  3. The building project is limited to the selection of materials that are well approximated by the assemblies and materials contained in the Path 3 B3 LCA Material Selection Calculator.

Using B3 LCA Material Selection Calculator:

The calculator contains a database with GWP impacts for ten different categories of material, such as cladding and roofing. Only one material type may be selected per category, and it must make up 60% or more of the material used by the building in that category (i.e., it must be the primary material type). If a building does not contain material in a particular category, that category must be entered as NA.

Within the calculator’s database, specific materials are ranked by their GWP impact. The lowest GWP materials are assigned a material Impact Score group number of 1 or 2. Materials with medium GWP impact are assigned a material Impact Score of 3. High GWP materials are assigned a material Impact Score of 4 or 5. The building’s Impact Score (averaged) across all categories must be 1.6 or lower to achieve compliance using this documentation path. If the building’s Impact Score is greater than 1.6, Paths 1 and 2 may be used instead to allow the design team more flexibility to apply additional impact reduction strategies not available under Path 3. A series of graphs comparing the GWP impact of functionally equivalent building materials is provided to assist the practitioner in selecting materials that will help achieve compliance. These may be useful for guiding structure and envelope decisions in the early design phases.

Design:

M.1A: Documentation of either Path 1, Path 2 or Path 3

GWP Reduction Path 1 – Whole-Building LCA Approach

  • Upload the Reference Building LCA model and selected reports showing GWP impact. These reports should show impacts for life-cycle phases A–C only and must include total whole-building GWP impact as well as a breakdown of GWP by assembly type. Total GWP for the Reference Building must also be input separately.
  • Upload an iteration of the whole-building LCA model and reports that show reduction in GWP impact compared to the submitted Reference Building LCA model. Total GWP reduction must also be input into the Tracking Tool.
  • Required submittal files for Athena users:
    • Athena IE base files (Reference Building and current design iteration)
    • Reports: “Detailed LCA Results by Assembly Group Embodied Effects” in table format (reports for both Reference Building and current design iteration)
  • Required submittal files for Tally users:
    • Revit model files with included Tally specifications (Reference Building and current design iteration)
    • Reports: “Full Building Summary” (reports for both Reference Building and current design iteration)

GWP Reduction Path 2 – Assembly-level LCA Approach

  • Upload the Reference Model structural bay model (Athena IE or Tally) and selected reports showing GWP impact. These reports should show impacts for life cycle phases A–C only, and must include total whole-building GWP impact as well as a breakdown of GWP by assembly type. Total GWP for the Reference Model must also be input into the Tracking Tool.
  • Upload an iteration of the structural bay model (Athena IE or Tally) and reports that show reduction in GWP impact compared to the submitted Reference Model structural bay model. Total GWP for this model iteration must also be input separately.
  • Required submittal files for Athena users:
    • Athena IE base files (Reference Model and current model iteration).
    • Reports: “Detailed LCA Results by Assembly Group Embodied Effects” in table format (reports for both Reference Case and current model iteration).
  • Required submittal files for Tally users:
    • Revit model files with included Tally specifications (Reference Model and current model iteration)
    • Reports: “Full Building Summary” (reports for both Reference Model and current model iteration)
  • Required submittal files for One Click LCA users:
    • If Revit was used upload Revit model files used to output One Click LCA model (Reference Building and current design iteration). Include PDF of “Building Materials” tab showing building materials and mapping.
    • Reports: Excel outputs “detailReport” (reports for both Reference Building and current design iteration)

GWP Reduction Path 3 – Material-Level LCA Approach

  • Upload a preliminary version of the completed Path 3 Compliance Calculator demonstrating selection of compliant assemblies. The Impact Score computed by the calculator must be 1.6 or lower to achieve compliance. Also input the Impact Score to the Tracking Tool.

Final Design:

M.1A: Whole-Building LCA Model and Documentation of either Path 1, Path 2 or Path 3

Whole-Building LCA Model

  • Regardless of the compliance path chosen, all projects must upload a final whole-building LCA model and selected reports showing GWP impact at the end of the construction documents (CD) phase. These reports should show impacts for life cycle phases A–C only, and must include total whole-building GWP impact as well as a breakdown of GWP by assembly type. The model should represent the closest available approximation of the building as it will be built. If the design team selected GWP Reduction Path 1 to demonstrate compliance, the final Selected Building Design LCA model satisfies this requirement.

GWP Reduction Path 1 – Whole-Building LCA Approach

  • If there has been changes to the Owner’s Project Requirements (OPR) (established in P1), confirm that the Reference Building model uploaded at the end of the Design phase still meets the updated OPR. If not, the Reference Building model may need to be updated.
  • Upload the final Selected Design whole-building model and reports that show 10% reduction in total building GWP impact compared to the submitted Reference Building. The Selected Building Design should represent the closest available approximation of the building as it will be built.
  • Required submittal files for Athena users:
    • Athena IE base files (Reference Building and Selected Building Design)
    • Reports: “Detailed LCA Results by Assembly Group Embodied Effects” in table format (reports for both Reference Building and Selected Building Design)
  • Required submittal files for Tally users:
    • Revit model files with included Tally specifications (Reference Building and Selected Building Design)
    • Reports: “Full Building Summary” (reports for both Reference Building and Selected Building Design)

GWP Reduction Path 2 – Assembly-Level LCA Approach

  • If there has been changes to the Owner’s Project Requirements (OPR) (established in P1), confirm that the Reference Model structural bay model uploaded at the end of the schematic design phase still meets the updated OPR.
  • Upload the final Selected Design Model structural bay model and reports that show 10% reduction in GWP impact compared to the submitted Reference Model structural bay model. The Selected Design Model should represent the closest available approximation of the building as it will be built.
  • Required submittal files for Athena users:
    • Athena IE base files (Reference Model and Selected Design Model)
    • Reports: “Detailed LCA Results by Assembly Group Embodied Effects” in table format (reports for both Reference Model and Selected Design Model)
  • Required submittal files for Tally users:
    • Revit model files with included Tally specifications (Reference Model and Selected Design Model)
    • Reports: “Full Building Summary” (reports for both Reference Model and Selected Design Model)

GWP Reduction Path 3 – Material-Level LCA Approach

  • Upload a final version of the completed Path 3 Compliance Calculator. The Impact Score computed by the calculator must be 1.6 or lower to achieve compliance. Also input the Impact Score to the Tracking Tool.

Select which product option(s) to pursue. Early product research can help the project team capitalize on opportunities for products contributing to multiple credits and options. Individual products may contribute under either Option 1 or Option 2 but not be counted toward both.

The required scope of this guideline is for permanently installed building products, excluding mechanical, plumbing, electrical (MEP), and specialty equipment and items purchased for temporary use on the project. Furniture is not considered permanently installed and is not required to be included in the submission.

Option 1 is for projects with permanently installed products that have a product-specific declaration adhering to third-party certification programs to ensure that they conform to ISO 14044, which defines how LCAs are critically reviewed.

Option 2 is for projects with products with either product-specific or Environmental Product Declarations (EPDs) or industry-wide EPDs. Products must be sourced from multiple manufacturers, as indicated in the Required Performance Criteria. Various thresholds are available to accommodate stages of EPD development in different industries.

The table below compares different EPD formats to product-specific declarations:

Product-Specific Declaration Industry-Wide EPD Product-Specific EPD
Data are critically reviewed x x x
Data are specific to product x x
Data are reported according to product category rules (PCR) x

Reference Guide for Building Design and Construction. Washington, DC: US Green Building Council, 2013. Print.

Suggested Implementation in the Design Process:

In Predesign and early design, refer to Additional Resources section below for information on product-specific declarations, EPDs, and how to obtain them.

Use the databases listed in Tools & Resources to search for common building product categories with disclosed EPDs. Material categories that are likely to have EPDs are wood products and interior finishes.

If, at this stage, a particular manufacturer and/or product is intended as a partner, contact manufacturer and learn about their current product life-cycle assessments. Refer to Tools and Resources section of M.1B for information on how to create a product-specific declaration or an Environmental Product Declaration.

Establish an initial list of products or building materials for the project. Review and update this list at each stage of the project. This will be useful for the Design phase in order to research compliant products. Also track whether the products or product categories identified are anticipated to meet option 1 (product-specific declaration) or option 2 (EPD).

Through the design process, refine selection of products and/or materials and establish a list of potential manufacturers. Review online resources for available product-specific declarations or EPDs that match the specified products or building materials for the project. Contact manufacturers and inquire about their current product life-cycle assessments. If needed, provide information on how to create a product-specific declaration and/or an EPD. Create specifications ensuring that this guideline can be met. Some additional information on specifying compliant products can be found under Additional Resources below.

Begin collecting documentation on compliant products by compiling product-specific declarations and/or EPDs and upload to the B3 Guidelines Tracking Tool. Declarations are typically in the form of a PDF document. If a product-specific declaration or EPD is in the process of being created for a particular product or building material, a PCR may be submitted in the Design phase and replaced by the completed documentation at the Final Design phase in the B3 Guidelines Tracking Tool.

In the construction documents phase of the project, establish final selection of compliant products and/or materials, ensuring that at least five meet the criteria here. It is recommended that the design team have researched and specified more than five products anticipating that some may not be eventually installed in the product due to requested changes or product availability. In the Tracking Tool submit at least five final product-specific declarations or EPDs. If necessary, make appropriate updates to products where only a PCR was submitted in the previous phase. Keep all documentation pertaining to specified products or materials.

During construction check in periodically with team members (contractors, subcontractors, and suppliers) to verify progress toward guideline achievement and address any gaps in credit compliance.

Continually track substitutions and change orders to ensure replacement products comply with the guidelines. Any product and/or building material substitutions or submittals should be carefully reviewed by the design team for compliance with the guidelines. Compile documentation to verify environmental claims for each product. Retain product data for all materials that contribute to guideline compliance.

Documentation of Product-Specific Declarations:

Declarations based on a life-cycle assessment of a product but not constituting a full EPD: To document this claim, the project team must provide the following information:

  • Name (declaration holder or producer, typically the manufacturer)
  • Contact information
  • Product type
  • Product name
  • Product description
  • Summary of impact categories measured and overall values
  • Functional unit
  • Standards met
  • Independent review body name, including a review statement.

Documentation of Environmental Product Declarations (EPDs)

Documentation of an EPD (this includes Industry-wide or “generic” declarations, and product-specific Type III declarations). The project team must provide the following:

  • Declaration holder (the company, usually the manufacturer, that the EPD is attributed to).
  • EPD program operator (the entity that creates and registers the EPD).
  • LCA verifier (the third-party entity that verifies the life cycle assessment).
  • PCR reviewer (the third-party entity that has reviewed the product category rules).
  • During the selection of products with EPDs, identify two items about the document: the type of EPD it is, and the summary that will be uploaded for guideline compliance.

Note that similar products from the same manufacturer can be counted as separate products if they have distinct formulations, but not if they are just aesthetic variations or reconfigurations. For example: Paints of different gloss levels are separate products, but different colors of the same paint, or different colorways of the same carpet, are not. During collection of EPDs ensure that EPD documentation includes a summary sheet of measured impacts.

Design:

  • M.1B: Submit at least five different Product Declarations or Environmental Product Declarations that comply with the guideline requirements.

Final Design:

  • M.1B: Submit at least five different Product Declarations or Environmental Product Declarations that comply with the guideline requirements.

Training Session Slides – Using LCA For Sustainable Design (PDF)

Appendix M-1a: Material Selection Calculator

Standard EN15978: “Sustainability of construction works – Assessment of environmental performance of buildings – Calculation method” https://standards.iteh.ai/catalog/standards/cen/62c22cef-5666-4719-91f9-c21cb6aa0ab3/en-15978-2011

Environmental Product Declarations: The International EPD® System: www.environdec.com/

Healthy Building Network and Pharos: www.healthybuilding.net/content/pharos-v3

Thinkstep: www.thinkstep.com

Underwriter’s Laboratory (UL) SPOT database: www.ul.com and https://spot.ulprospector.com/en/na/BuiltEnvironment

ICC Evaluation Service: ICC-ES technical evaluations: https://icc-es.org/building-products-listing-program/

NSF International: www.nsf.org

Declare Products: https://living-future.org/declare/

Cradle2Cradle: www.c2ccertified.org

Greenguard: UL Environment’s GREENGUARD Certification program: https://www.ul.com/services/ul-greenguard-certification

Ecoinvent: http://www.ecoinvent.org/

Athena Sustainable Materials Institute: http://www.athenasmi.org/our-software-data/lca-databases/

openLCA Nexus: https://nexus.openlca.org/database

ISO Standards: http://www.iso.org/iso/home.htm

Reference Building

A base-case whole-building LCA model used to compare performance with design cases. Embodied global warming potential (GWP) reductions for compliance Path 1 are measured by comparing embodied GWP of the design cases to the embodied GWP of the Reference Building. There are four accepted methods of determining the design of the Reference Building, discussed in the Meeting the Guidelines section.

Selected Building Design

The final design case whole-building LCA model, representing the building as it is expected to be built. The final global warming potential (GWP) reduction for compliance Path 1 is measured by comparing embodied GWP of the Selected Building Design to the embodied GWP of the Reference Building.

Reference Model

A base-case structural bay LCA model used to compare performance with design cases. Embodied global warming potential (GWP) reductions for compliance Path 2 are measured by comparing embodied GWP of the design cases to the embodied GWP of the Reference Model. The exact contents of the structural bay model are discussed in the Meeting the Guidelines section.

Selected Design Model

The final design case structural bay LCA model, representing the building as it is expected to be built. The final global warming potential (GWP) reduction for compliance Path 2 is measured by comparing embodied GWP of the Selected Design Model to the embodied GWP of the Reference Model.

All Guidelines