UL Brings Automation and Metrics to the Circadian Stimulus Discussion

By Randy Reid with Katie Smith

With the last two years of our workspaces changing and becoming more work-from-home and a lot of co-op shared workspaces, lighting manufacturers have added new products that contribute to a circadian-effective lighting plan. The importance of circadian lighting is something that Adam Lilien from UL cares deeply about. Adam was recently a guest panelist on the National Lighting Bureau’s discussion on circadian lighting, and he finds that the growth in technology of circadian solutions will greatly benefit people who spend their days working in buildings. He mentioned that after their publication of the Design Guideline for Promoting Circadian Entrainment with Light for Day-Active People, the team realized that the industry desperately needs a methodology for measurement. I found this extremely intriguing, so I sat down with him to learn more about what UL is working on in terms of circadian solutions.

A new service from UL is a patent-pending UL Circadian Field Measurement System. This service will allow UL field engineers to take measurements in customers' buildings and create a floor plan with color-coded spaces to show the lighting designers where light output is above or below their circadian-effective lighting goals. Essentially, this is allowing for field measurements to be taken with results being demonstrated in a heat map format. This service can be utilized in existing retrofits or new conditions.

Instead of working off computer-aided design plans, the system captures the actual light at eye level, including ambient light from windows and skylights and artificial light from luminaires, along with all of the reflectances from ceilings, walls, floors, furniture, and more. With those measurements, algorithms are used to calculate the effectiveness of the light’s ability to signal to the brain that it is daytime. Those calculations then derive the circadian heat map that illustrates in color where people in that space will reach the circadian goals. These are voluntary goals defined by the lighting designer, based on the circadian model that they have chosen.

This map shows up in green, red, and yellow. The color green shows where lighting is above the goal – so a space where the circadian-effective lighting is successfully being delivered to the eyes. Yellow and red show where the lights aren’t achieving the goal. This tells lighting designers that they have a few different moves to make, whether it be adding more layers of light, such as a wall wash or a desk lamp, utilizing dimming controls, or improving the reflectance of the space through painting the walls, opening the blinds, or making the furniture options brighter. Adam explained, “This is to measure the circadian-effective lighting achieved in the space. We’ve designed it for the three different published models. Lighting designers can now “see” the results of their designs after installation and commissioning, or for a retrofit, what they are starting with.”

Ideally, this voluntary testing service will be of interest for business owners, lighting designers or specifiers, space planners, and even building occupants. This isn’t just a trendy concept; it’s something that allows building owners to differentiate their properties and boost occupancy.

A huge struggle Adam found is that circadian-effective lighting is not a visual thing - what his team is measuring and reporting is not the first thing people notice. It's not like the visual aspect of light. They are focusing on how the light impacts human circadian physiology and what messages the brain is receiving about that light. He explained, “We learned that you can’t just tell the industry how to conduct circadian goal measurements, but that we had to make it easier.” Adam said UL comes into play because the industry needed an organization to figure out a way to automate the process to make assessing the amount of circadian stimulus in larger spaces practical and affordable.

"We are focusing on how the light impacts human circadian physiology and what messages the brain is receiving about that light."

There is a struggle with assigning how properly designed lighting spaces are better for circadian synchronization, and how it’s possible to deliver consistent results. Even with that struggle, Adam feels that UL’s new systems will bring the right tools to the market and remove barriers for industry adoption. He said that sometimes in the lighting industry, the hardest part is getting the word out. I am pleased to use this as an opportunity to help spread the news about these fantastic systems.

If you are interested in learning more, you can visit UL’s booth at LightFair, reach out to your local UL representative, or visit www.ul.com/services/human-centric-lighting where a video about the UL Circadian Field Measurement System is available. A webinar will soon be announced with a more in-depth look at the UL Circadian Field Measurement System and UL Circadian-Effective Luminaire Performance Certification. ■