Circadian lighting gets its due from standards-bearer

It’s called “circadian entrainment,” and it refers to anything that promotes and supports the circadian rhythms of people who are active during the day and inactive at night (sorry, nocturnal night-shifters). It is the focus of lighting-design guidelines recently released by Underwriters Laboratories, Inc., the same non-profit whose initials adorn tags for lighting products in our homes.

Generally speaking, the goal of the guidelines, called DG 24480, is to establish “recommended practices” (vs. mandates) for the lighting industry, practices that will lead to the broad understanding, development and implementation of lighting for vision as well as for “non-visual circadian entrainment.”

In the bigger sense, this effort (and a similar – and competing – effort by the Illuminating Engineering Society, or IES), is part of what’s known as human-centric lighting (HCL). Intended to support people’s emotional, physical and mental well-being, HCL is getting a lot of press these days, if for no other reason than well-received ability to “tune” the brightness and color temperature of LED lighting to mimic our natural environment. It targets indoor spaces that are largely sun-deprived: homes, workspaces, retail locations, prisons, hospitals, schools, etc.

The thinking is, as scientists learn more about the effects of lighting on circadian rhythms, so should we expect lighting manufacturers, specifiers, electrical contractors and even building owners to know more, too, and to act on that understanding. That’s because good, circadian-entrainment lighting leads us to healthier, happier lives; many scientific studies over the past several decades prove that.

Developed over the past year or two, UL’s final guidelines were released in December 2019; the IES is still working on a similar report. (In fact, the two are at odds over whose report is or will be the definitive source; more on that here.)

To learn more about the UL guidelines, writer Craig DiLouie of Electrical Contractor magazine sat down last May with Adam Lilien, UL’s global business development manager. Following are the highlights from the interview.

  • The title of the 50-page publication is Underwriters Laboratories Inc. 24480 Design Guideline for Promoting Circadian Entrainment with Light for Day-Active People.
  • The guidelines are the work of a UL task force created in association with the Lighting Research Center and populated by experts in lighting, education, medicine, government, military, and other industries. Input also came, worldwide, from lighting designers, building owners, lighting manufacturers, scientists who specialize in sleep, and other stakeholders.
  • Recommendations were based on field studies proven to show circadian lighting promotes “better sleep, mood and behavior.”
  • According to Lilien, the guidelines should contribute to the improvement of building occupants’ lives, with “greater alertness, less reliance on stimulants, better sleep quality, and the resulting improvements in health.”
  • The UL released the guidelines in hopes that “associations, institutes, commercial entities and non-profit organizations can (collaboratively) advance the understanding of science-based illumination, especially as it related to human-centric lighting and its impact on health and well-being.”
  • The upshot of the guidelines, from Lilien: “(M)ore lighting is required during the day, and less lighting during the night. … As a lighting industry, we have provided illumination for vision for over 100 years. Over the past several decades, we have come to know that we are under-illuminating our indoor spaces during the day, and over-illuminating them at night. While there is certainly more for us to understand, science-based studies concur that new lighting design practices can improve human health and well-being today.”
  • A shift already is taking place, Lilien notes, in the healthcare industry, where much research on lighting and its effect on patient care has taken place.
  • While some energy codes run contrary to the guidelines for heightened illumination, Lilien expects change over time given the energy efficiencies of LED lighting paired with new technologies in occupancy sensors, advanced controls and the Internet of Things.