Pilot-Credits MRpc132: Procurement of Low Carbon Construction Materials 1-2 points

Credit language

Intent

To reduce the embodied carbon of materials used in construction.

Introduction
As with many LEED credits, the 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 methodology, which is referenced in this credit, increases the directional correctness of procurement decisions intended to reduce embodied carbon. However, the absolute value of carbon emissions reductions should not, at this stage, be understood to be numerically precise. As datasets and evaluation tools improve, uncertainty 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 concrete, slurry, shotcrete)
    • Masonry (CMU)
    • Steel (rebar, steel wire and mesh, plate steel, structural steel, steel decking, cold formed steel, open-web steel joists)
    • Aluminum (aluminum extrusions, thermally improved aluminum extrusions)
    • Wood & Composites (dimensional lumber, plywood/OSB sheathing, glass mat gypsum sheathing, prefabricated wood products, composite lumber, mass timber)
    • Insulation (board, blanket, foamed-in-place, blown)
    • Cladding (insulated metal panel, metal 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 materials, follow 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 Estimate, 100% CD BIM bill of materials, or 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 methodology, determine 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 concrete, slurry, shotcrete)
    • Masonry
    • Steel (rebar, steel wire and mesh, plate steel, structural steel, steel decking, cold formed steel, open-web steel joists)
    • Aluminum (aluminum extrusions, thermally improved aluminum extrusions)
    • Wood & Composites (dimensional lumber, plywood/OSB sheathing, glass mat gypsum sheathing, prefabricated wood products, composite lumber, mass timber)
    • Insulation (board, blanket, foamed-in-place, blown)
    • Cladding (insulated metal panel, metal 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 Estimate, 100% CD BIM bill of materials, or 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.

Sample bECIb
Material Category	mECIb v2019 (kgCO2/unit)	x	Building Quantity	=	bECIb per material (kgCO2)
Concrete	XX kgCO2/m3	x	XX m3	=	XX kgCO2
Steel	XX kgCO2/mt	x	XX mt	=	XX kgCO2
Timber	XX kgCO2/m3	x	XX m3	=	XX kgCO2
Aluminum	XX kgCO2/kg	x	XX kg	=	XX kgCO2
Glazing	XX kgCO2/m2	x	XX m2	=	XX kgCO2
Gypsum Board	XX kgCO2/m2	x	XX m2	=	XX kgCO2
Insulation	XX kgCO2/m2	x	XX m2	=	XX kgCO2
Carpet	XX kgCO2/m2	x	XX m2	=	XX kgCO2
Ceiling Tile	XX kgCO2/m2	x	XX m2	=	XX kgCO2
					Total XX kgCO2
Divide total XX kgCO2 by project sf to get bECIb :					XX kgCO2/sf

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.

Sample bECI a
Material Category	mECIa (kgCO2/unit)	x	Building Quantity	=	bECIa per material (kgCO2)
Concrete	XX kgCO2/m3	x	XX m3	=	XX kgCO2
Steel	XX kgCO2/mt	x	XX mt	=	XX kgCO2
Timber	XX kgCO2/m3	x	XX m3	=	XX kgCO2
Aluminum	XX kgCO2/kg	x	XX kg	=	XX kgCO2
Glazing	XX kgCO2/m2	x	XX m2	=	XX kgCO2
Gypsum Board	XX kgCO2/1000 m2	x	XX m2	=	XX kgCO2
Insulation	XX kgCO2/m2	x	XX m2	=	XX kgCO2
Carpet	XX kgCO2/m2	x	XX m2	=	XX kgCO2
Ceiling Tile	XX kgCO2/m2	x	XX m2	=	XX kgCO2
					Total XX kgCO2
Divide total XX kgCO2 by project sf to get bECIa :					XX kgCO2/sf

Step 3:

Complete calculations per below to assess achieved project embodied carbon reduction.

PROJECT embodied carbon reduction
bECIa	/	bECIb	=	XX %
Subtract XX% from 100%			=	XX% Project Embodied Carbon Reduction

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 estimate, exported BIM material quantities bill of materials, as-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 unavailable, with additional documentation of advocacy to manufacturers asking for product specific EPDs.

APPENDIX

• UW CLF Material Category Reports v2019, including 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.

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