Intent

To reduce the embodied carbon of materials used in construction.

Introduction

As with many LEED creditsthe environmental outcomes of a project team strategy are dependent on many factors. This credit is no different and is largely based on life-cycle environmental impact data. The goal of this pilot credit is to improve that data and the comparability of data from life cycle assessment (LCA) results. The University of Washington/Carbon Leadership Forum methodologywhich is referenced in this creditincreases the directional correctness of procurement decisions intended to reduce embodied carbon. Howeverthe absolute value of carbon emissions reductions should notat this stagebe understood to be numerically precise. As datasets and evaluation tools improveuncertainty should decrease and decisions based on this data should be improved. Your participation in this pilot credit is an important step in catalyzing and accelerating this improvement.

Requirements

Step 1 - Building Embodied Carbon Intensity - Baseline Calculation:

Calculate the building embodied carbon intensity baseline (bECI_b) for the project:

• Use materials embodied carbon intensity baselines (mECI_b) published by the University of Washington/Carbon Leadership Forum or other approved data provider to calculate the embodied carbon for materials used in the project.
  • The following materials must be included if they are used on the project:
    • Concrete (ready mixed concreteslurryshotcrete)
    • Masonry (CMU)
    • Steel (rebarsteel wire and meshplate steelstructural steelsteel deckingcold formed steelopen-web steel joists)
    • Aluminum (aluminum extrusionsthermally improved aluminum extrusions)
    • Wood & Composites (dimensional lumberplywood/OSB sheathingglass mat gypsum sheathingprefabricated wood productscomposite lumbermass timber)
    • Insulation (boardblanketfoamed-in-placeblown)
    • Cladding (insulated metal panelmetal panel)
    • Finishes:
      • Gypsum Board
      • Acoustical Ceiling Tiles
      • Resilient Flooring
      • Carpet
    • Communications (data cabling)
    • Bulk Materials (flat glass)
  • Other materials may be included at the discretion of the project team
    • To determine the mECI_b for other materialsfollow supplemental credit guidance available in the LEED pilot credit library

Multiply the appropriate mECI_b by the total quantity of each material used in the construction of the project.

Material quantities shall reflect the final as-built project and be consistently drawn from either 100% CD Construction Estimate100% CD BIM bill of materialsor Contractor procurement data.

Units can be quantified and calculated as IP or SI but must be consistent throughout.

Sum the individual material embodied carbon figures for all materials to calculate the bECI_b.

Step 2 - Building Embodied Carbon Intensity – Verified Reduction Calculation

Utilize lower embodied carbon materials in the construction of the project and document a verified reduction in the project’s embodied carbon intensity.

• Utilizing a third party verified Environmental Product Declaration with applied UWCLF methodologydetermine the actual material embodied carbon intensity (mECI_a) for the materials used in the project.
  • The following materials must be included if they are used on the project:
    • Concrete (ready mixed concreteslurryshotcrete)
    • Masonry
    • Steel (rebarsteel wire and meshplate steelstructural steelsteel deckingcold formed steelopen-web steel joists)
    • Aluminum (aluminum extrusionsthermally improved aluminum extrusions)
    • Wood & Composites (dimensional lumberplywood/OSB sheathingglass mat gypsum sheathingprefabricated wood productscomposite lumbermass timber)
    • Insulation (boardblanketfoamed-in-placeblown)
    • Cladding (insulated metal panelmetal panel)
    • Finishes:
      • Gypsum Board
      • Acoustical Ceiling Tiles
      • Resilient Flooring
      • Carpet
    • Communications (data cabling)
    • Bulk Materials (flat glass)
  • Other materials may be included at the discretion of the project team

Multiply the appropriate mECI_a by the total quantity of each material used in the construction of the project.

Material quantities shall reflect the final as-built project and be consistently drawn from either the 100% CD Construction Estimate100% CD BIM bill of materialsor Contractor procurement data.

Units can be quantified and calculated as IP or SI but must be consistent throughout.

Sum the individual embodied carbon figures for all materials to calculate the actual building embodied carbon intensity (bECI_a).

Calculate the percent difference between the bECI_b and the bECI_a.

Points are awarded based on the reduction in bECI_b and bECI_a. as follows:

• Low range reduction (0-30%) - 1 Point
• Mid-range reduction (30+%) - 2 Points

Provide Building Embodied Carbon Intensity (bECI) Report including the following:

• Material embodied carbon intensity baselines (mECI_b)
• Actual material embodied carbon intensities (mECI_a) for all included material categories as a table.
• Building Embodied Carbon Intensity Baseline (bECI_b)
• Actual building embodied carbon intensity (bECI_a)
• State the year of the baseline and actual carbon intensity data sets.
• If using an existing building vs demolishing and re-building: Create a baseline new construction building embodied carbon intensity limit by taking assumed and reasonable new construction material quantities multiplied by material embodied carbon intensity limits. Create project verified building embodied carbon intensity with as constructed quantities of materials for renovation.

Submittals

General

Register for the pilot credit

• Participate in the LEEDuser pilot credit forum
• Complete the feedback survey:

Feedback Survey

Documentation/Compliance

Step 1:

Complete calculations per below to create building embodied carbon intensity baseline (bECI_b). Units can be quantified and calculated as IP or SI but must be consistent throughout. [view:embed_resource==12704422]

Step 2:

Complete calculations per below to create actual building embodied carbon intensity (bECI_a). Units can be quantified and calculated as IP or SI but must be consistent throughout. [view:embed_resource==12704471]

Step 3:

Complete calculations per below to assess achieved project embodied carbon reduction. [view:embed_resource==12704482]

Step 4:

Submit calculations per the above in table format or using third party tool that utilizes mECI_b v2021 methodology. Submit documentation that supports the declared actual material embodied carbon intensities (mECI_a’s) and material quantities used in calculations.

• Compliant documentation includes:
  • Material Quantities: 100% CD estimateexported BIM material quantities bill of materialsas-procured material quantities.
  • Material Embodied Carbon Intensities: Third Party Verified EPDs for materials included in above listed Material Categories with mECI_b v2021 methodology applied to address EPD variability and lack of transparency. Industry average EPDs with mECI_b v2021 methodology applied are acceptable if manufacturer specific EPDs are unavailablewith additional documentation of advocacy to manufacturers asking for product specific EPDs.

APPENDIX

• UW CLF Material Category Reports v2019including material embodied carbon limits and associated methodology.
• User Guide to utilizing the free and open source Embodied Carbon in Construction Calculator (EC3) for demonstrating LEED compliance.