855773520-LEED-v5-ID-C-Reference-Guide-Launch-Edition-1 - Page 339
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vibrant and true to their actual hue. This is especially important in environments where color differentiation is critical, such as in medical facilities, retail spaces, or galleries. CRI information for the luminaire can be found in manufacturer specifications. The luminaire must have a CRI of at least 90.
Color rendering: TM-30-20 TM-30 is a newer method developed by the Illuminating Engineering Society (IES) [139] for measuring color fidelity. The luminaire requirements for this credit are based on the Priority Level 1 criteria for the Preference design intent recommendation in TM-30-20 Annex E (see Table 5). This threshold was selected to align with WELL v2 Feature L08 - Electric Light Quality. [140]
Table 8. Color rendering requirements for TM-30 method
| Measure | Col2 | Requirement |
|---|---|---|
Fidelity index | Rf | 78 or higher |
Gamut index | Rg | 95 or higher |
Red Local Chroma Shift | Rcs,h1 | -1% to 15% |
PATH 3. PROXIMITY TO WINDOWS FOR DAYLIGHT ACCESS
This path involves designing the building floorplates and interior layout to have regularly occupied areas located in close proximity - within 20 feet (six meters) - of envelope glazing: for example, windows, curtain walls, or other transparent elements in the building façade.
The 30% threshold serves as a baseline or entry-level standard that aligns with WELL v2 Precondition L01 — Light Exposure, encouraging projects to incorporate daylight access into the design. [141] Projects aiming for more extensive daylighting strategies should explore Path 4. Daylight Simulation .
PATH 4. DAYLIGHT SIMULATION
Daylight is dynamic and highly dependent on local climate and site conditions with daily and seasonal variations. These dynamic qualities can be explored during the design process using daylight simulation tools and daylight performance metrics standardized by the daylight design community. Incorporating simulation early in the design phase supports the optimization of building form, window placement, façade elements, and interior configurations to achieve the best possible balance of natural light.
139 Illuminating Engineering Society (IES), TM-30-20, http://www.ies.org 140 WELL Standard v2, https://www.v2.wellcertified.com/en/wellv2/light/feature/8. 141 WELL Standard v2. (n.d.). Retrieved from https://v2.wellcertified.com/en/wellv2/light/feature/1
U.S. Green Building Council LEED v5 Reference Guide for Interior Design and Construction, April 2025 Launch Edition 328