1.Under Beta Update:
Delete "Under In response to public comments and project team inquiries," from first sentence.
Revise third sentence to read as: "Further, if buildings or building elements cannot be re-used significantly, changes to the lifecycle analysis option of the credit encourage projects to conduct whole building life cycle assessment as an integral design component for many more buildings.
Revise the first three sentences in the second paragraph to read as:
"Former LEED v4 credit Option 1 (Historic Building reuse
) and Option 2 (Renovation of Abandoned and Blighted Building) have been combined into Option 1 for v4.1. The former Credit Option 3 (Building and Material Reuse) now is replaced with a consolidated option 1 and includes two pathways for calculating building reuse
. These changes consolidate the calculation methodology for all types of reuse
and restore the LEED v2009 credit pathways (MR c1.1: Building reuse
– maintain existing walls, floors and roofs; and MR c1.2: Building reuse
– maintain interior nonstructural elements) that provided simpler, more prescriptive calculations.
Revise first sentence in third Paragraph to read: "Credit Option 2 (formerly Option 4), Whole Building Life Cycle Assessment, now has ..."
Revise last sentence in third paragraph to read: "Finally, to greater reward embodied carbon reductions through reuse
, project teams can now earn up to four points in Credit Option 4 by incorporating building element reuse
and/or salvaged ..."
2. Under Step by Step Guidance, revise Option 3 to Option 1.
Revise language to read as:'"New general guidance for v4.1 applicable to Paths 1 and 2:
Identify non-structural and structural elements of the existing space (e.g. walls, floors, roofs, doors, floor coverings, ceiling systems, etc.) that can be retained separately and in combination to select best pathway/approach for re-use (Path 1 or Path 2). Include elements reused onsite and/or salvaged from offsite as part of the reuse
Projects that incorporate part of an existing building but do not meet the requirements for this credit may apply the reused portion toward the achievement of MR Credit Sourcing of Raw Materials. To apply the reused portion for the Sourcing of Raw Material credit, determine the cost of each material. This cost will be the actual cost paid or, if the material came from on-site, the replacement value. The replacement value can be determined by pricing a comparable material in the local market; exclude labor and shipping. If a project team receives a discount from a vendor, the replacement value should reflect the discounted price as opposed to the list value. When the actual cost paid for the reused or salvaged material
is below the cost of an equivalent new item, use the higher value (actual cost) cost of the new equivalent item in the calculations. When the cost to reclaim an item found on-site is less than the cost of an equivalent new item, use the cost of the new item (or replacement cost).
3. revise Option 4 to Option 2. and delete "Step 1" from first sentence.
At the end of the paragraph that starts: "Ensure that the scope of the analysis..." add "with the following clarifications:
The system boundary of the analysis must include a cradle to grave scope (modules A-D). However, some gaps in sub-modules may exist due to the materials or dataset chosen and design optimizations attempted for the project. Gaps in sub-modules are allowed so long as the system boundary in total encompasses a cradle-to-grave assessment. The required modules for a compliant whole building life-cycle analysis include:
o Product stage: include modules A1-A3.
o Construction process: include at least module A4.
o Use Stage: Include at least one module from B1-B5.
o End of life stage: Include at least one module from C1-C4.
For projects demonstrating impact reductions compared to a baseline: The LCA software or tool used for the baseline and proposed design must be the same, with the same modules and impact categories evaluated.
Note that LCA software or tools must have ISO-14044-compliant data sets and conform to ISO 21931-2017 and/or EN 15978:2011 and their data must meet the requirements of ISO 21930-2017 and EN 15804. Typically, the software tool providers will document they meet these criteria in the LCA output report.
Additional Guidance for Whole Building LCA Tool Providers:
The system boundary of a whole building LCA must include modules A-D as defined in ISO 21930 and EN 15804. LCA tools must have ISO-14044-compliant data sets and conform to ISO 21931-2017 and/or EN 15978:2011. Further, the underlying data must meet the requirements of ISO 21930-2017 and EN 15804.
If LCI data is not available for certain products, LCA tools can incorporate product EPD data into their ISO 14044 compliant LCI datasets as long as:
o The EPD has not expired.
o The EPD scenarios are representative of contemporary technologies and/or practice, and are relevant to the project location.
o The EPD data reports all indicators and system boundary information required by WBLCA tools.
o The EPD or LCA clearly indicates which product (manufacturer and product name) or geographical region it reflects in compared to industrywide results of a material available in the tool.
4. Under further explanation, delete and replace with:
Option 1: Building and Material Reuse
The v4 calculation of formerly credit Option 3. Building and Material Reuse in LEED v4 reference guide has been changed. Steps 1 and 3 have been removed. Step 2 (Reuse off-site materials) remains in effect.
The LEED v4 Building and Material Reuse concept and calculation for “surface area and layers of reuse” is no longer utilized. Instead, project teams will calculate reuse
as follows below for Path 1 and Path 2.
Path 1 Calculations: Maintain Existing Structural Elements: Walls, Floors, Roofs and Envelope
calculation is based on the surface areas of major existing structural and envelope elements per equation 3. Structural support elements such as columns and beams are considered part of the larger surfaces they support, so they are not quantified separately.
Prepare a spreadsheet listing all envelope and structural elements within the building. Quantify each item, listing the square footage of both the existing area and the retained area. Determine the percentage of existing elements that are retained by dividing the square footage of the total retained materials area by the square footage of the total existing materials area. Include any salvaged or reused materials that were sourced off-site and integrated into the project as part of the reused area
in the calculations.
Take measurements as if preparing a bid for construction of a building. For structural floors and roof decking, calculate the square footage of each component. For existing exterior walls and existing walls adjoining other buildings or additions, calculate the square footage of the exterior wall only and subtract the area of exterior windows and exterior doors from both the existing and the reused area
tallies. For interior structural walls (e.g., shear walls), calculate the square footage of one side of the existing wall element. Table 1 provides an example of the calculations for Path 1.
Table 1. Sample Building Structure and Envelope Reuse Calculation for Path 1.
(Insert Table here)
Exclude the following items from this calculation: nonstructural roofing material, window assemblies, structural and envelope materials that are deemed structurally unsound, hazardous materials, and materials that pose a contamination risk to building occupants.
Equation 3. Percentage of existing building reuse
– maintain existing structural elements:
Existing building reuse
= (area reused on-site+area reused from off-site)/(existing building area-hazardous materails area) x 100
Path 2 Calculations: Maintain Interior Nonstructural Elements
This pathway focuses on reuse
of interior, nonstructural elements and compares the retained and reused elements with the total completed area of interior elements. It is not necessary to calculate the total area of existing interior nonstructural elements prior to demolition. Include any salvaged or reused materials that were sourced off-site and integrated into the project as part of the reused area
in the calculations.
Take measurements as if preparing a bid for flooring, ceiling, or painting:
• Finished ceilings and flooring areas (tile, carpeting, etc.). Use square footage or square meters to determine area.
• Interior nonstructural walls. Determine the finished area between floor and ceiling and count both sides.
• Exterior structural and party walls. If the interior finishes (e.g., drywall and plaster) have been reused, count only one side.
• Interior doors. Count surface area once.
• Interior casework. Calculate the visible surface area of the assembly
Include items that have been saved but may have been relocated, such as full-height demountable walls and doors that were rehung. Also include reused items purchased or sourced off-site from other buildings or projects, such as from salvage yards or donations.
Fixed items, such as nonstructural walls and doors, are included in this credit and count toward the percentage of reuse
when they perform the same function (e.g., doors reused as doors). If materials are used for another purpose (e.g., doors made into tables), they can count toward the achievement of MR Credit: Sourcing of Raw Materials, but they cannot count toward both credits.
Table 2 illustrates a spreadsheet for determining credit compliance. The total area of all new and existing building materials (following construction) is determined. The total area of only the existing and reused components is then entered. The sum of the existing materials is then divided by the sum of the total building materials to obtain the overall percentage of retained components. Since the overall percentage of reused nonstructural interior materials exceeds 30% of the total area of all nonstructural interior building materials, the project earns 1 point.
Table 2. Sample Interior Nonstructural Element Reuse Calculation for Path 2.
Determine the percentage of existing elements that are retained by dividing the total area of all retained interior nonstructural elements by the total area of interior nonstructural elements following Equation 4.
Equation 4: Percentage of existing building reuse
– maintain interior nonstructural elements:
Interior nonstructural reuse
= ((area of retained interior nonstructural elements+area of elements reused from offsite))/(total area of interior nonstructural elements) x 100
Projects that incorporate part of an existing building for reuse
but do not meet the requirements for Path 2 may apply the reused portion toward the achievement of MR Credit Construction and Demolition Waste Management. To do so, determine an approximate weight or volume for existing building elements and count them as waste diversion
in the credit calculations.
7. Revise Option 4 to: "Option 2 (formerly Option 4): Whole Building Life Cycle Assessment
Refer to Option 4 in the LEED v4 reference guide with the following modifications and additions:
Add the following language under the paragraph that starts "This option now has four thresholds..."
"Developing an appropriate baseline building is necessary for a compliant WBLCA to show reductions in global warming potential and other impacts. Product and material environmental characteristics in the baseline building must reflect standard design practices and typical material selection choices for the project location and building type. For instance, assuming zero-percent recycled content
in some metal products or concrete mixes does not reflect typical practice in North America. Project teams should look to common project types in the region and review industry resources in order to develop accurate baselines for claimed impact reductions. In documenting the credit, project teams will need to include a description of why the baseline structure
systems represent typical construction for the project, location, and building type."
Revise the next paragraph to read as: "Within Option 2, choose Path 1 (whole building life cycle analysis of the project) and/or Path 2, 3 or 4 (comparative whole-building life cycle analysis) as outlined in credit requirements. Note that for Path 1, project teams must complete a standard Whole Building Life Cycle Assessment (WBLCA) of the proposed design and report the impact categories in a WBLCA report, however there are no thresholds for reductions necessary to earn this point."
Revise the three bullet points to read as:
2 points (3 points Core & Shell) – demonstrated impact reduction of at least 5% in Global Warming Potential and at least 2 other impact categories.
3 points (4 points Core & Shell) – demonstrated impact reduction of at least 10% in Global Warming Potential and at least 2 other impact categories.
4 points (5 points Core & Shell) – demonstrated impact reduction of 20% in Global Warming Potential and at least 10% in at least 2 other impact categories. This option must also incorporate reuse
and/or salvaged materials ..."
Modify the following section under Required Documentation as follows:
Documentation requirements for former Option 1 (historic building reuse
) and Option 2 (renovation of abandoned or blighted building) are now included under the restructured Option 1: Building and Material Reuse.
Documentation requirement for Option 1 Building and Material Reuse:
Path 1: Structural and nonstructural reused elements table and calculations
Path 2: Interior nonstructural reused elements table and calculations
Documentation requirement for Option 2, Whole Building LCA:
WBLCA report for structure
Documentation requirement for Option 2, Whole Building LCA Path 2, 3 and 4:
WBLCA report that includes description of LCA assumptions, scope and analysis process for baseline building and proposed building, life cycle impact assessment summary showing outputs of proposed building with percent change from baseline building for all impact categories, and a narrative indicating which path was pursued and how reductions were achieved.
Add a new section on Exemplary Performance:
Option 1: Path 1: Reuse 90% of the building
Option 2: Achieve Path 4 and show 40% reduction in GWP