1. An overview of WELL
The International WELL Building Institute (IWBI) launched the WELL Building Standard in 2014, placing human health at the centre of building assessment. WELL v2, launched in 2020, further developed its approach to light.
WELL v2 has ten concepts. The Light concept addresses visual lighting, circadian considerations, glare and visual comfort to support the experience of building occupants.
2. Light features discussed in the original article
WELL distinguishes preconditions from optimizations. The table below translates the feature labels, classifications and thresholds printed in the original January 2025 Chinese article. It is an archival account of that article, not a current certification checklist; the applicable WELL version and project scorecard govern certification.
| Code in original | Label in original | Classification in original | Requirement quoted in original |
|---|---|---|---|
| L01 | Light exposure | Precondition | 75% of workstations within 7.5 m of windows or equivalent lighting |
| L02 | Visual lighting design | Precondition | IES RP-1 or EN 12464-1 |
| L03 | Circadian lighting design | Precondition | Melanopic EDI ≥ 150 lx at 75% of workstations |
| L04 | Glare reduction | Precondition | UGR ≤ 19 in offices |
| L05 | Enhanced daylight exposure | Optimization | ≥ 200 lx equivalent daylight illuminance |
| L06 | Visual quality | Optimization | Ra ≥ 90; R9 ≥ 50 |
| L07 | Colour quality | Optimization | Full spectrum or Ra ≥ 95 |
| L08 | Light pollution management | Optimization | Control outdoor spill light |
3. Circadian lighting design
The original article discusses daytime melanopic equivalent daylight illuminance (m-EDI) in work areas as a way of considering circadian light exposure.
Its example requirements are:
• At least 75% of regularly occupied workstations receive melanopic EDI ≥ 150 lx during 09:00–13:00.
• Alternatively, provide a circadian stimulus (CS) of at least 0.3.
• Calculate α-opic quantities with reference to CIE S 026:2018.
These are the figures quoted in the original article. It connects circadian design with tunable-white luminaires and intelligent lighting controls in commercial offices.
4. A technical design workflow
The article recommends addressing lighting calculations and equipment selection early in design:
1. Melanopic assessment: use calculation tools, such as those discussed in the original article (LUmiCalc and DIALux evo), with luminaire spectral power distribution (SPD) data to assess α-opic quantities.
2. Luminaire selection: obtain complete SPD data and consider high colour rendering (Ra ≥ 90, with Ra ≥ 95 preferred in the example) and tunable-white capability.
3. Controls: provide scheduled scene changes through DALI-2 DT8 or an equivalent system.
4. Glare: coordinate luminaire optics and placement; the article uses UGR ≤ 19 as an office design target.
5. Documentation: prepare lighting calculations, luminaire data sheets and a description of the control system for the assessment process.
5. GKC’s project approach
The original article describes GKC’s involvement in lighting design for WELL projects in Changzhou, Suzhou and Shanghai. It identifies four priorities:
• Early involvement: coordinate daylight and electric lighting with the architectural concept.
• Data-led decisions: use melanopic calculations rather than experience alone.
• Equipment verification: request SPD data and α-opic information from manufacturers.
• Commissioning: use on-site spectral measurements to check the installed light environment.
The original article reports an office project in Suzhou combining DALI-2 DT8 tunable-white controls with daylight sensing. The stated scenes were 5000 K / 200 melanopic lx in the morning and 4000 K / 150 melanopic lx in the afternoon; the article reports successful assessment of its circadian lighting provision.
Conclusion
WELL encourages project teams to consider lighting as part of the wider human experience of buildings. Melanopic assessment, circadian lighting and colour quality extend the conversation beyond basic visual tasks.
For a project pursuing WELL certification, involve a specialist lighting team early and confirm the requirements of the applicable certification version. GKC can support concept design, technical coordination and documentation.
References
Sources for the related figures and research mentioned in this article.
[1] International WELL Building Institute (IWBI). https://www.wellcertified.com/ — Publisher of the WELL Building Standard
[2] CIE S 026/E:2018 — CIE System for Metrology of Optical Radiation for ipRGC-Influenced Responses to Light. https://cie.co.at/publications/cie-system-metrology-optical-radiation-iprgc-influenced-responses-light-0 — CIE S 026:2018 defines α-opic quantities and melanopic EDI
[3] EN 12464-1:2021 Light and lighting — Lighting of work places — Part 1: Indoor work places. https://standards.iteh.ai/catalog/standards/cen/53fc4ff7-e7df-4ebd-a730-0d5f0ea888e0/en-12464-1-2021 — Office writing, reading and data processing: UGR ≤ 19, Ra ≥ 80