WELL Tip: Navigating preconditions for the Light concept

WELL Tip: Navigating preconditions for the Light concept

Thursday, March 15, 2018
/ By:
Tori Shepherd

Interior of Obayashi's Technical Research Institute. The first WELL Certified™ project in Japan as well as the first WELL Certified™ New and Existing Building project in the world.

Have you ever approached a WELL precondition and wondered where to begin? Not to fret - we’ve launched a Navigating preconditions series to help project teams get started incorporating a number of preconditions from different WELL concepts into their project’s design and policies.

What are the building blocks of the Light concept? 

Within the Light concept, feature requirements provide illumination guidelines that aim to minimize disruption to the body’s circadian system, enhance productivity, support good sleep quality and provide appropriate visual acuity where needed. Key terms include ambient lighting, illuminance (lux), visible transmittance (VT), equivalent melanopic lux (EML), glazing, color rendering index (CRI), correlated color temperature (CCT), light reflectance values (LRV), spatial daylight autonomy (sDA) and annual sunlight exposure (aSE).

Project teams looking to refresh their knowledge of subjects referenced throughout the Light Concept can consult the Glossary for more information.

Who are the relevant stakeholders?

Depending on project scope, it may be helpful to consider engaging the following team members when implementing the light features:

  • Architect
  • Electrical engineer
  • Interior designer
  • Landlord
  • Lighting consultant
  • Vendor: Building controls and light fixtures

How should you approach a feature? 

  1. Understand the feature intent and background. Here you can learn how requirements aim to address particular challenges associated with human health and well-being. If you’re interested in learning more, check out the Light WELLography on the Build WELL App. 

  2. Read feature requirements and verification methods.

  3. Determine stakeholders.

  4. Consult the FAQs: your question may already have been answered!

  5. Explore equivalent standards, codes or practices that may be more applicable to your locality.

  6. Explore published Alternative Adherence Paths (AAPs). If all other options are exhausted, the project may develop and submit a new AAP which meets the feature intent in a method dissimilar from feature requirements.

  7. If pursuing another certification program, consult the BREEAM, Green Star, LEED or Living Building Challenge Crosswalks for guidance on dual certification overlaps and efficiencies, such as features that align to provide partial equivalence or full compliance.

  8. Seek inspiration from IWBI’s Article Library, such as WELL Story: Light at Arup.

  9. Consult Standard Citations for additional information. You can find these insightful resources by expanding the tab at the bottom of each feature on the Digital Standard.

  10. If questions remain after consulting these resources, reach out to your WELL Coaching Contact for guidance and technical support.



To support visual acuity by setting a threshold for adequate light levels and requiring luminance to be balanced within and across indoor spaces.

Strategies to Consider

While not mandatory, below are a few strategies that you can evaluate when developing your own project-specific approach to meeting Feature 53:

  • Determine the illuminance levels on the horizontal plane through light modeling or by taking measurements with a lux meter, as outlined in the testing protocols in Performance Verification Guidebook.

  • Remedy low illuminance levels with supplemental lighting, such as task lights. Supplemental lighting should be available during performance verification.

  • Implement brightness management strategies through minor renovations, such as replacing fixtures or installing additional fixtures in dimly lit hallways, repainting walls a lighter color in a dark breakroom, reupholstering furniture with lighter fabrics and replacing partitions with interior glass.

  • Design a lighting plan that incorporates various types of lighting, but avoids dark and excessively bright spots and glare. Diffused lighting solutions and uplighting can help distribute light more evenly throughout the space.

  • Projects struggling to achieve part 1b should consult the published AAP.

  • Projects in China should consult the approved equivalency.

Questions to drive the conversation

  • What fixtures are installed? Is the space designed to achieve specific illuminance levels on the horizontal work plane?
  • Should my team use modeling software or conduct our own testing of illuminance levels prior to performance verification?
  • What types of tasks will be conducted in the space? What illuminance levels will these tasks require?
  • Can my project improve our light distribution and brightness management strategies through minor renovations?
  • Will tasks lights offer a viable solution? Can their availability be incorporated into company policy?

Relevant Resources



To support circadian health by setting a minimum threshold for daytime light intensity.

Strategies to Consider

While not mandatory, below are a few strategies that you can evaluate when developing your own project-specific approach to meeting Feature 54:

  • Supplemental lighting: additional overhead lights, floor lamps and task lamps may be able to add brightness to the space.

  • Specify high color temperature lamps and light fixtures that display a broader range of the color spectrum as represented by the lamp's spectral power distribution (which can be requested from manufacturers if not already provided).

  • If pursing part 1a, enhance access to daylight: the project team may consider strategic building configurations, as well as the incorporation of skylights, atriums, clerestory windows, light shelves or advanced glazing technologies.

  • Specify high light reflectance values (LRV) for interior surfaces, such as the ceiling, walls and furniture coverings.

  • Engage a lighting consultant who can accurately determine compliance through EML calculations and a comprehensive light model that quantifies both natural and artificial light.
  • Consult the published AAPs for the most recently approved solutions.

Questions to Drive the Conversation

  • Does someone on my project team understand how to calculate EML?
  • Can the manufacturer provide me with the fixture’s melanopic ratio or spectral distribution?
  • What should my project specify when sourcing lighting fixtures to more likely meet EML requirements?
  • Should my team use modeling software? Can we take advantage of previously drafted renderings?
  • Does our lighting design focus on the vertical surface, rather than solely the horizontal surface?
  • Does our project include fixed standing desks, which will need to comply with Feature 54?

Relevant Resources

  • Table L1 in Appendix C of the WELL Building Standard explains how to calculate the EML and provides a spreadsheet to aid in these calculations.



To minimize direct and overhead glare by setting limits on the luminous intensity of luminaires.

Strategies to Consider

While not mandatory, below are a few strategies that you can evaluate when developing your own project-specific approach to meeting Feature 55:

  • Determine the shielding angles of luminaires in regularly occupied spaces through product specification sheets or by contacting the manufacturer. Consider using the equivalency for Unified Glare Rating (UGR) in lieu of angles of shielding. UGR values can generally be found in luminaire specifications or calculated in lighting design software.

  • Purchase new shielding (louvers, diffusers or lenses), thus reducing the possibility of glare on occupants. Lighting manufacturers may be able to provide shielding devices that can be attached to existing fixtures.

  • Purchase new light fixtures that have have glare control integrated in the fixture design.

  • Pay close attention to spot lights and small sources of light, as these are usually sources of glare.
  • Design a lighting plan that incorporates uplighting to distribute a percentage of a fixture’s light towards the ceiling, thus preventing glare while providing sufficient ambient lighting.

  • The equivalency for Unified Glare Rating (UGR) also offers the easiest way to assess compliance with part 2. Workstations should have a UGR of 19 (or less).

Questions to Drive the Conversation

  • Does someone on my project team understand shielding angles including calculation and how to retrieve them?
  • As a Core & Shell project, what is considered within the scope of this feature?

Relevent Resources 

  • The International WELL Building Institute has generated the below resources to aid in understanding Feature 55. For part 1, the shielding angle "a" can be calculated by subtracting the cut-off angle from 90 degrees, as demonstrated in Diagram A. The cut-off angle is the critical viewing angle beyond which the source of the luminaire can no longer be seen.

Diagram A:









For part 2, the angle from the center of view "a" can be calculated as depicted in Diagram B.

Diagram B:



Tori serves on the Market Solutions team at the International WELL Building Institute (IWBI). As a WELL Faculty member and LEED Green Associate, Tori utilizes her expertise in environmental sustainability and human health as she provides technical assistance and customer support to project teams and industry professionals.

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