A Summary Of WELL Building Standard Version 2.0 Lighting Requirements

Here is a summary of the WELL Building Standard Version 2.0 Lighting Requirements:

Feature L01: Light Exposure – Provide indoor light exposure through daylight and electric light strategies.

Option 1: Daylight simulation
The project demonstrates, through computer simulations, that one of the following conditions are achievedOption 2: Interior layout
One of the following requirements is met:

a. At least 30% of the regularly occupied area is within a 20 ft horizontal distance of envelope glazing in each floor.
b. Common spaces have unassigned seating and can accommodate at least 15% of regular occupants at any given time. At least 70% of all seating in the spaces is within a 16 ft horizontal distance of envelope glazing.

Option 3: Building design

One of the following requirements is met:

a. The envelope glazing area is no less than 7% of the regularly occupied floor area for each floor level.
b. The floor plate is no more than 65 ft between opposite walls that each have envelope glazing, and there are no opaque obstructions higher than 3.2 ft within a 20 ft horizontal distance of the envelope glazing.

Option 4: Circadian lighting design

The following requirement is met:
The project meets the threshold of Tier 1 of Feature L03: Circadian Lighting Design.

Feature L02: Visual Lighting Design – Provide visual comfort and enhance visual acuity for all users through electric lighting.

Option 1: Visual lighting design

The following requirements are met:

1. All indoor and outdoor spaces (including transition areas) comply with the illuminance thresholds specified in one of the following lighting reference guidelines:

1. 1. IES Lighting Library, Lighting Applications Standards Collection.
   2. EN 12464-1&2: 2011 or EN 12464: 2021.
   3. ISO 8995-1:2002(E) (CIE S 008/E:2001).
   4. GB50034-2013.
   5. CIBSE SLL Code for Lighting.
2.  The illuminance thresholds take into consideration the tasks and the age groups of the occupants.

Option 2: Predetermined light levels

The following requirements are met:

1. More than 50% of the occupants are under the age of 65.
2. The area of outdoor space within the project boundary is less than 5% of the interior project area.
3. At least 90% of the interior project area is comprised of the following space types and meets the associated illuminance thresholds:

Feature L03: Circadian Lighting Design – Support circadian and psychological health through indoor daylight exposure and outdoor views.
For All Spaces Except Dwelling Units & Guest Rooms

For workstations used during the daytime, electric lighting is used to achieve the following thresholds:

a. The following light levels are achieved for at least four hours (beginning by noon at the latest) at a height of 18 in above the work-plane for all workstations in regularly occupied spaces:
b. The light levels are achieved on the vertical plane at eye level to simulate the light entering the eye of the occupant.

For Dwelling Units & Guest Rooms

The following requirements are met in each dwelling unit:

a. Electric lighting is used to achieve the following light levels:

b. The light levels are dimmable. If automated lighting is used, it is automatically dimmed after 8:00 pm.
c. The light levels are achieved in living rooms and kitchens at a height of 55 in in the center of the room. For studio apartments and guestrooms without living rooms, also test in the center of the room. If workstations are present, light levels are achieved at a height of 18 in above the work-plane.

Feature L04: Electric Light Glare Control – Minimize glare caused by electric light.

For All Spaces Except Industrial

Choose between the following:
Option 1: Luminaire considerations
All luminaires within regularly occupied spaces (excluding wall wash fixtures, concealed fixtures, emergency lighting and decorative fixtures installed as specified by the manufacturer) meet one of the following requirements when measured at light output representative of regular use conditions:

a. 100% of light is emitted above the horizontal plane.
b. Classified with Unified Glare Rating (UGR) of 19 or lower.
c. Luminance that does not exceed 6,000 cd/m² at any angle between 45 and 90 degrees from nadir.

Option 2: Space considerations
All regularly occupied spaces meet the following requirement:
Unified Glare Rating (UGR) of 19 or lower.

For Industrial

Choose between the following:
Option 1: Luminaire considerations
All luminaires within regularly occupied spaces (excluding wall wash fixtures, concealed fixtures, emergency lighting and decorative fixtures installed as specified by the manufacturer) meet one of the following requirements when measured at light output representative of regular use conditions:

a. 100% of light is emitted above the horizontal plane.
b.Classified with Unified Glare Rating (UGR) of 19 or lower.
c. Luminance that does not exceed 6,000 cd/m² at any angle between 45 and 90 degrees from nadir.

Option 2: Space considerations
All regularly occupied spaces meet the following requirement:
Unified Glare Rating (UGR) of 19 or lower.

Feature L05: Daylight Design Strategies – Provide daylight exposure indoors through design strategies.

Part 1 Implement Daylight Plan (Max: 2 Points)

For All Units Except Dwelling Units & Guest Rooms

The following requirement is met:
The project demonstrates that the following conditions are achieved on each floor:

For Dwelling Units & Guest Rooms

The following requirement is met:
One of the following requirements is met in each dwelling unit:

Part 2 Integrate Solar Shading (Max: 2 Points)

For All Spaces Except Dwelling Units & Guest Rooms

The following requirements are met in regularly occupied spaces:
All vertical envelope glazing has shading that meets one of the following:

For Dwelling Units & Guest Rooms

The following requirements are met in dwelling units:
All vertical envelope glazing has shading that meets one of the following:

Feature L06: Daylight Simulation – Ensure indoor daylight exposure through daylight simulation strategies.

For All Spaces Except Dwelling Units & Guest Rooms

The project demonstrates, through computer simulations, that the following conditions are achieved in each floor:
Regularly occupied spaces achieve one of the following targets:

For Dwelling Units & Guest Rooms

The project demonstrates, through computer simulations, that the following conditions are achieved:
Each dwelling unit achieves one of the following targets:

Feature L07: Visual Balance – Create lighting environments that enhance visual comfort.

For All Spaces
Choose between the following:
Option 1: Parameters for visual balance
Ambient lighting in all regularly occupied spaces meets at least three of the following requirements:

a. Horizontal and vertical luminance contrast ratios for an ambient light system is no more than 10:1 between adjacent independently controlled zones.
b. Illuminance uniformity ratio of at least 0.4 or 1:2.5 (minimum light level: average light level) is achieved on any horizontal task plane within a space.
c. One of the following:

1. A lighting automation system is in use and automatic changes in lighting characteristics, such as light levels, changes in color and distribution take place over a period of at least 10 minutes.
2. A lighting automation system is not in use.

d. The Correlated Color Temperature (CCT) in each room for similar fixtures is consistent (±200 K) at any point of time.

Option 2: Design for visual balance
Lighting is designed by a lighting professional and takes into account the following considerations:

a. Luminance ratios on vertical and horizontal adjacent zones.
b. Illuminance uniformity on horizontal task planes.
c. Changes in lighting characteristics, such as light levels, changes in color and distribution.
d. Correlated Color temperature (CCT) of lights used.

Feature L08: Electric Light Quality – Enhance visual comfort and minimize flicker for electric light.

Part 1 Enhance Color Rendering Quality (1 Point)

For All Spaces Except Circulation Areas

All luminaires in occupiable spaces (except decorative fixtures, emergency lights and other lighting for signage) meet at least one of the following color rendering requirements. If tunable white lighting is used, the requirements are met at 1000 K intervals from the lower end (with a minimum of 2700 K) to the higher end (with a maximum of 5000 K):

a. CRI (R_a) ≥ 90.
b. CRI (R_a) ≥ 80 and R9 (R₉) ≥ 50.
c. IES R_f≥ 78, IES R_g ≥ 100, -1% ≤ IES R_cs,h1 ≤ 15%.

For Circulation Areas

All luminaires (except decorative fixtures, emergency lights and other special-purpose lighting) meet at least one of the following color rendering requirements:

a. CRI (R_a) ≥ 80.
b. IES R_f ≥ 75, IES R_g ≥ 95, -7% ≤ IES R_cs,h1 ≤ 15%.

Part 2 Manage Flicker (2 Points)

For All Spaces
All luminaires (except decorative lights, emergency lights and other lighting for signage) and their controls within occupiable spaces meet at least one of the following requirements:

a. Classified as “reduced flicker operation” per California Title 24, when tested according to the requirements in Joint Appendix JA-10.
b. Recommended practices 1, 2 or 3 as defined by IEEE standard 1789-2015 LED.
c. Pst LM ≤ 1.0 and SVM ≤ 0.6 for indoor applications per NEMA 77-2017 or Commission Regulation (EU) 2019/2020.

Feature L09: Occupant Lighting Control – Provide individuals with access to customizable lighting environments.

Part 1

Enhance Occupant Controllability (Max: 2 Points)
For All Spaces
Meet the following:

1: Lighting zones
Ambient lighting systems meet the following requirement:
All regularly occupied spaces contain lighting zones as shown in the table below (note: individual rooms smaller than the areas below and/or that have occupancies less than those listed in the table are considered separate zones):

AND

2: Lighting control system
Each lighting zone meets the following requirements:

a. Lighting systems have at least three lighting levels or scenes that allow for changes in light levels.
b. ​​​​​​Lighting systems have the ability to change at least one of the following:

1. Color.
2. Correlated color temperature (CCT).
3. Distribution of light by controlling different groups of lights or through preset scenes.

c. All regular occupants have control over their immediate lighting environment through at least one of the following:

1. 1. Manual controls (e.g. switches or control panels) located in the same space as each lighting zone.
   2. Digital interface available on a computer or phone.

d. Lighting for presentation or projection walls are separately controlled.

Part 2

Provide Supplemental Lighting (1 Point)
For All Spaces except Dwelling Units & Guest Rooms
Meet the following:

1: Supplemental lighting availability
The project meets the following requirements:

a. Supplemental light fixtures (e.g., task lights) are provided upon request to all employees at no cost and requests are fulfilled within eight weeks.
b. At least one supplemental light fixture is available for trial purposes.

AND

2: Supplemental lighting requirements
Supplemental light fixtures meet the following requirements:

a. Light levels are controllable by occupants, independently from the ambient lighting system.
b. The location of the light is adjustable by users of the workstation.
c. Under intended use, the light-emitting element is not visible to users.

LightNOW has made a good-faith effort to accurately summarize information from the WELL Building Standard website. LightNOW is not responsible for any errors or omissions. This summary should not be relied upon for qualifying a building. The WELL Building Standard website should be used for qualifying a building to the WELL Building Standard: https://v2.wellcertified.com/en/wellv2/light

David Shiller

David Shiller is the Publisher of LightNOW, and President of Lighting Solution Development, a North American consulting firm providing business development services to advanced lighting manufacturers. The ALA awarded David the Pillar of the Industry Award. David has co-chaired ALA’s Engineering Committee since 2010. David established MaxLite’s OEM component sales into a multi-million dollar division. He invented GU24 lamps while leading ENERGY STAR lighting programs for the US EPA. David has been published in leading lighting publications, including LD+A, enLIGHTenment Magazine, LEDs Magazine, and more.

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