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White Light’s Role in Better Building Design

Sept. 4, 2018
Tunable white light is a big part of the WELL building design standard that strives to optimize well-being in buildings where we live and work.

By Craig Casey, Senior Building Science Engineer, Lutron Electronics Co., Inc.

The goal of the WELL Building Standard is refreshing and simple: Better buildings to help people thrive. White tuning is an increasingly important aspect of smart building design and one key to creating the right environment for the people in the space.

The WELL Building Standard, developed by the International WELL Building Institute, is a program committed to advancing health and well-being in buildings globally. WELL is changing the way people think about building design, operation and behavior by focusing on ways to optimize well-being in the spaces where we live and work. Tunable white fixtures and digital control can help buildings achieve WELL certification.

When your customers are looking to include tunable white in their latest project, especially in pursuit of WELL certification, you’ll want to make sure they are starting with a digital control solution. Digital control offers tremendous benefits from the customer’s perspective, but it is equally essential from the electrical wholesaler and contractor standpoint. When you start with robust, flexible, smart technology on the front-end, installation, setup, and even system adjustments will be much easier over time. Analog control solutions can be challenging and tedious, and the results are often inconsistent and unsatisfactory.

Compared to analog control, digital technologies:

• Deliver consistency and ensure that each fixture in the control protocol has the same light qualities

• Improve reliability and drastically reduce the risk of installation issues

• Provide precise control of color temperature

• Offer solutions that meet your project requirements from basic tunable white through full saturated color, and automated control over the course of a day.

Advanced, smart solutions ultimately make projects easier and less time consuming, delivering a more consistent, predictable lighting performance by simplifying the technical complexities of tunable white solutions.

So how does all this relate to WELL certification? WELL certification starts with seven concepts, each of which influences human behavior and helps define a wellness-focused environment: air, water, nourishment, light, fitness, comfort and mind. Features including mandatory “preconditions” and optional “optimizations” must be met within each concept. Well-designed tunable white control can be especially impactful in the Light Concepts area where it can contribute to preconditions including Visual Lighting Design (Feature #53) and Circadian Lighting Design (Feature #54) among others. It’s helpful for lighting distributors to understand the impact of these features on WELL certification.

Visual Lighting Design, Feature #53, defines required average light levels of 215 lux on the horizontal plane, measured at 30 inches above the floor, as well as independently controlled zones of light no larger than 500 sq. ft. This feature defines the appropriate brightness and contrast ratios on different surfaces among spaces and different surfaces within a space to avoid dark spots or excessively bright spots in a room.  Dimming, or tuning, selected fixtures (setting maximum lighting output to the appropriate illuminance level) helps designers meet the required contrast ratios. 

A lighting design can meet required average light levels with fixtures alone, but this strategy can result in very bright light, which is acceptable earlier in the day but considerably less desirable in the late afternoon when it can negatively affect sleep patterns. By using tunable white fixtures with independent control of intensity and correlated color temperature (CCT), along with a digital, tunable white control solution, lighting may be adjusted automatically and unobtrusively over the course of the day, scaling back from short wavelength violet/blue light in the morning and early afternoon, to a preferable warmer light in the late afternoon and evening. With a tunable white solution, you can meet required lux without compromising lighting comfort, and you are better set up to meet WELL Feature #54.

As an aside, digital controls can also enhance energy savings. While WELL certification does not focus on energy efficiency, it’s still a consideration in most commercial buildings. Lighting control solutions that integrate with daylighting strategies and occupancy sensors, for example, can play a significant part in reducing energy use.

WELL Feature #54 addresses Circadian Lighting Design, or lighting that provides appropriate equivalent melanopic lux (EML) in work areas to promote conditions that reinforce natural patterns of the human circadian cycle.

EML is calculated by measuring the visual lux and multiplying it by a ratio that correlates to the impact the light has on the body’s sleep/wake cycle. The Melanopic Light Intensity in Work Areas option requires at least 250 EML on the vertical plane facing forward for 75 % of the workstations for at least four hours each day. Lighting designers can find it challenging to provide the required EML and still design lighting that is comfortable and compatible with evolving circadian lighting principles. 

The blue light that helps meet EML during the day may not be desirable in the late afternoon due to color preference or energy efficiency. This is one motivator for the enhanced use of digital control with color tuning fixtures — they can provide the required EML light level during the day at lower power consumption and adjust to a lower EML light in the evening and night.

The WELL Building Standard is raising awareness of lighting designs that best support the people who live and work in a space. Committed to forward-thinking, people oriented, smart-building technologies, manufacturers are working to develop smart products and solutions that help lighting designers deliver ever-more comfortable, sustainable, productive work environments. Sustainable building practices help create the right environment and drive smart solution specifications. As distributors become more familiar with WELL requirements, they can also be better prepared to meet the advanced lighting control needs of their customers.

For many years, lighting design was focused primarily on energy savings, and performance often played a secondary role. In the last decade LED fixtures and controls have continued to deliver more efficient lighting control solutions, allowing performance to step into the spotlight. With the help of programs like the WELL Building Standard lighting professionals, manufacturers, and wholesalers are able to spend more time on the benefits of better lighting control for better buildings.


Craig Casey, senior building science engineer, Lutron Electronics Co. Inc., Coopersburg, PA, works at the intersection of theory and applied science, quantifying the human and energy benefits of leading-edge LED lighting/daylighting control systems. He is a former graduate assistant, lecturer and researcher at Penn State University where he earned his BA and MA in architectural engineering and is pursuing his doctoral degree. Craig is very active with the Illuminating Engineering Society and is a regular speaker and writer on lighting control. An avid cook, he lives in Coopersburg, Pa., with his wife and two daughters.   

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