This article continues the details of the updates on LEED v4.1 Building Design and Construction. Generally speaking, the LEED v4.1 becomes more achievable to meet their market transformation goal. And Its reference guide for beta participants was published in November 2020.
Integrative process:
Project team letter replaced the LEED v4 project's OPR (owner's project requirements) and BOD (basis of design) worksheet.
To describe the integrative process
To explain differences compared to a conventional approach.
To define the most important goals for each issue area.
The letter must be signed by all principal project team members and made available for key stakeholders.
Expanded primary areas (from the previous two systems) to analyze energy, water, site selection, social equity, health, and well-being.
A team can only choose two issues to discover.
A team can assess strategies around the key criteria.
The process became more flexible in the number of criteria and added exemplary performance credit for the following areas: site selection, social equity, health, and well-being.
The energy performance process becomes more achievable: only establish performance targets before schematic design without "simple box" energy modeling analysis.
[LT] Access to Quality Transit:
Adjustment to weekend trip minimums: only trips on the day with a higher number of trips are counted towards the threshold.
Added intermediate thresholds at 2 points and 4 points, respectively
Privately-run shuttles are only acceptable for Path 1 (access to public transit service) if the service is also made available to the public. (Path 2 is for accessing project-sponsored transit service)
[LT] Reduced Parking Footprint
Used the "Option" method instead of the "Case" method.
Removed carpool parking requirement
Simplified thresholds for all projects and became more achievable for compliance, such as:
Reduced parking capacity to "30% reduction below the base ratio" (from "20% reduction below the base ratio" from version 4)
Existing carshare vehicles in on- or off-street parking areas do not contribute to credit achievement.
Guaranteed carshare vehicle spaces will be dedicated for at least two years.
Unbundled the parking and development: Sell parking separately from all property sales or leases.
[SS] Protect or Restore Habitat
(Previously titled "Site Development—Protect or Restore Habitat")
Adjusted the threshold for soil restoration from 30% (including building footprint) to 15%.
Soil testing became only required for imported soils.
Removed floor area ratio requirement for vegetated roofs:
The project no longer needs to meet the FAR minimum for vegetated roofs to be considered part of the restored area.
Removed the Financial Support option.
Aligned with the SITES rating system, such as: using EPA level Ecoregion, USDA Natural Resources PLANTS database as referenced standards.
[SS] Open Space
Clarified requirements of outdoor space ratio: at least 30% of total site area, including building footprint to be open space.
7.5% of the total site area must be vegetated.
[SS] Rainwater Management
Thresholds for the percentile of rainfall event adjusted to less percentile requirements (90th,85th, and 80th percentile for all projects. 80th, 75th, and 70th for zero lot line project.)
LEED v4's 98th percentile (for all projects) and 95th percentile (for zero lot line project) requirements became exemplary performance credit.
Included both low-impact development (LID) and green infrastructure (GI) practices to manage rainwater.
Clarified acceptable LID and GI techniques and strategies
[WE] Outdoor Water Use Reduction
Increased points available. LEED v4 only offers up to 2 points. But in LEED v4.1, Core and Shell projects can earn up to 3 points when they reach a 100% reduction from baseline.
[EA] Grid Harmonization
(Previously titled "Demand Response")
Added the third option for building's load flexibility and management strategies.
Implemented strategies related to grid constraints, including Peak load optimization, Flexible operating scenarios, and Grid resilience technologies.
[EA] Renewable Energy
(Previously titled "Renewable Energy Production")
The credit combined the "Renewable Energy Production" credit and "Green Power and Carbon Offset" credit from LEED v4.
Three energy procurement strategies are available in tiers. A project can earn up to 5 points instead.
Tier1: On-site renewable energy generation
Tier2: New Off-site renewable energy
Tier3: Off-site renewable energy
[MR] Building Life-Cycle Impact Reduction
Consolidated building types to the existing structure and new construction. Reduced previous version to two options:
Option1: Building and Material Reuse
Option2: Whole-Building Life-Cycle Assessment.
For existing structure:
Projects can earn points by maintaining a certain percentage of an existing structural element, such as walls, floors, roofs, and envelopes.
Projects can also earn points by maintaining Interior Nonstructural Elements.
Simplified calculation methodology
Brought back LEED v2009 methodology with updated thresholds
For new construction:
Conduct a cradle-to-grave life-cycle assessment and select at least one path from the following.
Path 1: conduct a life cycle assessment of the project's structure and enclosure
Path 2: lower reduction threshold to a minimum of 5% reduction
Path 3: lower reduction threshold to a minimum of 10% reduction
Path 4: lower reduction threshold to a minimum of 20% reduction in Global Warming Potential (GWP)
[MR] Environmental Product Declaration
(Previously titled "Building Product Disclosure and Optimization—EPD")
In the Option 2 path, the valuation method changed from depending on the cost to evaluating the embodied carbon optimization report. For example,
With Embodied Carbon/LCA Action Plan is valued as ½ product
Less than 10% reductions in GWP (Global Warming Potential) is valued as 1 product
More than 10% reductions in GWP (Global Warming Potential) is valued as 1.5 products
More than 20% reductions in GWP (Global Warming Potential) is valued as two products
[MR] Sourcing of Raw Materials
(Previously titled "Building Product Disclosure and Optimization – Sourcing of Raw Materials")
Removed the product with a self-declared report as one of the creditable options.
Reduced product source threshold from at least five different manufacturers to three different manufacturers.
Increased "material reuse" criteria value from 100% to 200%.
[MR] Material Ingredients
(Previously titled "Building Product Disclosure and Optimization – Material Ingredients")
Any compliant report with a third-party verification counted for 1.5 products
Option1, Material Ingredient Reporting
Cost requirement lowered from 25% to 10% by cost.
Let the project team meet the credit via ten products instead of twenty.
Option2, Material Ingredient Optimization
The requirement lowered the threshold by cost from at least 25% to at least 10%. A project can also choose 10 products instead to earn the points.
Option3 is eliminated
[EQ] Low-Emitting Materials
Restructured credit around product categories. Increased to 8 product categories and simplified points system correlated with the number of compliant categories
Clarified that exterior doors and windows are included in the wall panels category, and skylights are in the ceiling category.
Under VOC emission evaluation, added requirement for manufacture statement. "Manufacture statements must also include a summary report from the laboratory that is less than three years old"
[EQ] Indoor Air Quality Assessment
Path 1 and path 2 under Option1, Flush-Out, remain unchanged
Option2, Air Testing
Previously did not specify what contaminants needed to be tested.
Tested methods are revised to 4 compounds(CO, PM10, PM2.5, Ozone) in Path1, Particulate Matter, and inorganic gases
Tested methods are modified to Path2, Reduced list of VOCs to 12 compounds
Eliminate maximum concentration limit for total volatile organic compounds (TVOCs)
Added more options to allow monitoring instruments and test methods.
[EQ] Daylight
Under Option1, "Spatial Daylight Autonomy and Annual Sunlight Exposure," LEED v4.1 reduced the sDA threshold to 40%, 55%, and 75%.
Under Option2, "Illuminance Calculation," LEED v4.1 reduced the percentage of regularly occupied floor area threshold to 55%, 75%, and 90%.
Under Option3, "Measurement," adjusted thresholds of the regularly occupied floor area percentage and points to 55%, 75%, and 90%.