Things could get ugly in human-centric lighting (HCL). The category is still young, but already there’s a battle to define, standardize, certify and otherwise bless tunable white lighting practices to support circadian rhythms.
In one corner is the not-for-profit Illuminating Engineering Society (IES), the “recognized technical and educational authority on illumination” since 1906. In the other corner is Underwriters Laboratory (UL), the mostly-for-profit certification body best known for product-safety standards.
Both groups are drafting “Recommended Practices” (RP) for healthful lighting – often referred to as HCL or circadian lighting – for simulating natural daylight in built environments, primarily through shifts in LED brightness and color temperature.
The scientific (and financial) case for HCL is mounting. Research shows fairly convincingly that simulated daylighting can improve physical, mental and emotional well-being. As a result, HCL products and principles are quickly propagating through work places, schools, hospitals, hotels, prisons, homes and other sun-deprived spaces.
What’s the best way to implement HCL? IES will release its Recommended Practices report soon. UL published its draft report last month. IES is not happy about it.
In a statement issued last week, IES claimed (in bold letters) that UL’s non-consensus process lacks rigor and its report would lack authority on such an important matter of public health.
It's no wonder so many groups want to lead the circadian-lighting movement.
They all want a piece of the biophilia action – the biggest thing going in wellness these days. The term has come to represent humankind’s innate connection to nature, rooted in a few hundred thousand years of evolving in the great outdoors.
Biophilic design encourages access to nature within built environments – whether through “living walls” plastered with plants, ample windows with views, airy skylights and atriums …. or some simulation thereof. HCL is a classic tool for mimicking nature (“biomimicry”) through changes in lighting intensity and color temperature to roughly replicate natural daylight patterns from dusk until dawn.
Scientific evidence abounds for the health benefits of circadian lighting when you're trapped indoors for 90% of the day, as we humans are. It is now big business for office buildings and hospitality, also prisons and schools, and soon homes and apartments where builders, developers and smart-home integrators play.
Get in on the conversation! Join CE Pro's Biodigitry group on linkedin.
What Irks IES
For about the first 100 years of its existence, UL certified mostly electrical- and fire-related products for safety. Today, however, the group peddles the UL mark for a host of other causes – cybersecurity, interoperability, energy savings, sustainability, and product performance, to name a few.
Then there’s the Illuminating Engineering Society, which does lighting. Just lighting. 113 years of lighting.
As such, the organization should drive standards and related initiatives in the emerging field of circadian lighting, right? IES thinks so. UL, however, wants in on the action.
Just as IES is about to publish its RP on circadian lighting, along comes UL last month with its own report, prompting IES’s recent nastygram.
UL itself says its RP is “not being developed as a consensus (ANSI) document,” according to IES, highlighting the crime in bold. UL’s draft report is open for “public comment” through May 28, but only via an “invitational process,” IES notes.
“Without the full rigor of an ANSI approved Standard,” IES warns (again in bold), “non-consensus based information cannot be deemed to have been fully vetted and lacks the authority to provide public guidance regarding means or methods that affect public health.”
IES goes on to urge the lighting industry (bold again) “to exercise caution when considering a non-consensus document for design, application, product qualification or regulatory purposes.”
IES prefaces the admonishment with a lengthy recitation of its own bona fides as “the recognized Standards Developing Organization for establishing lighting applications Standards in North America.”
Its committees comprise “a balance of volunteers including producers, users and general interest constituencies,” the organization explains, “and IES processes for committee membership and Standards development are accredited by the American National Standards Institute (ANSI).”
And besides, IES has the smartest minds in the business when it comes to lighting and wellness, with contributions from “prominent researchers, lighting scientists, and lighting practitioners experienced in the subject of light and human health, some of whom have been involved in this field for over 30 years.”
Lighting and Health: IES vs. UL
The impact of lighting on health wellness is nothing new to IES. The organization established a Light and Human Health Committee over a decade ago, and authored its first Technical Memorandum on the effect of light on human health in 2008 (IES TM-18-08, reaffirmed in 2018).
Here's the summary:
Light and Human Health: An Overview of the Impact of Optical Radiation on Visual, Circadian, Neuroendocrine, and Neurobehavioral Responses
In brief, this Technical Memorandum describes the retinal mechanisms involved when optical radiation signals are converted into neural signals (a phenomena called phototransduction) for vision and for other body functions. Optical radiation reaching the retina not only impacts on how humans see the world, it also regulates physiology and behavior, both directly and indirectly. This includes acute effects such as suppressing pineal melatonin production, elevating morning cortisol production, increasing subjective alertness, enhancing psychomotor performance, changing brain activation patterns to a more alert state, elevating heart rate, increasing core body temperature, activating pupil constriction, and even stimulating circadian clock gene expression.
Last year, IES outlined its forthcoming publication, Recommended Practice for Supporting the Physiological and Behavioral Effects of Lighting in Daytime Environments, in the June 22, 2018, issue of ANSI Standards Action:
BSR/IES RP-4x-201x, Recommended Practice for Interior Lighting Installations in Consideration of the Circadian, Neuroendocrine, and Neurobehavioral Effects of Ocular Light Exposure. (new standard)
Stakeholders: Lighting practitioners, designers, architects, members of the educational community, utilities, government, and the general public.
Project Need: A recommended practice developed with the consensus process and including peer-reviewed current research does not exist for this area of lighting.
Summarize the state of the art research on the circadian, neuroendocrine and neurobehavioral effects of ocular light exposure as they pertain to daytime lighting in interior spaces (including but not limited to schools and educational facilities and other institutional facilities). To propose recommendations for lighting standards on light intensity, spectrum, timing and pattern as well as the measurement, quantification and reporting of lighting in the context of these “nonvisual” responses to light.
Now, just as IES prepares to release its draft report, along comes UL's RP 24480, Recommended Practice and Design Guideline for Promoting Circadian Entrainment with Light for Day-Active People. (Entrainment refers to the alignment of our biological circadian clocks with external cues, especially lighting, that suggest it’s time to sleep, wake up, or be alert.)
The UL paper shouldn’t be a complete surprise to IES. In April 2018, UL announced a collaboration with the respectable Lighting Research Center (LRC) at Rensselaer Polytechnic Institute to “develop a recommended practice for the specification, measurement, and application of lighting to support circadian entrainment of individuals in daytime work environments.”
According to the announcement back then:
The task group will produce a set of practical recommendations and methods, grounded in science, that can be broadly implemented by addressing how to specify lighting for daytime applications, how to accurately measure circadian light, and how specification can be achieved, not only through the use of ceiling fixtures, but also by windows, skylights, luminous panels, and plug-in lighting.
See below for some highlights of UL's RP 24480.
UL Overreach? Parallels to HDMI
Has UL gone too far? Back in 2015, the organization shifted gears from mostly safety-related initiatives to a potential new profit center in “performance verification,” starting with HDMI. If an HDMI cable advertised 4K support, then a UL mark would verify the claim.
Who was UL to appoint itself overlord of HDMI-performance standards?! A fire-and-safety certifier inserting itself into the nuanced video-transmission business? The go-to HDMI-testing house at the time was DPL Labs, whose owner Jeff Boccaccio feigned flattery that late-comer UL would set up a competing shop.
“Noting a high level of similarity to DPL’s programs and position in the description of the new UL service, we take it as a real compliment to our work,” Boccaccio wrote in a 2015 CE Pro blog post. “We’re thrilled that anyone, let alone the leading ‘global independent safety science company’, has decided to stand alongside DPL to also provide independent HDMI testing.”
Not surprisingly, Boccaccio questioned whether a video-industry outsider could properly and thoroughly test HDMI and related devices without the extensive lab and field experience of a specialist like DPL.
“To test, with authority,” he wrote, “requires a deep understanding, gained only from extended immersive experience in high-speed digital testing ….”
When it comes to wellness-related lighting, IES expresses similar concerns about UL’s “authority” in a category it only recently claimed.
WELL Building Standard
UL and IES aren't the only certifiers in town when it comes to circadian lighting.
There's also the WELL Building Institute, purveyor of WELL Certification covering a host of wellness-related conditions in built environments, including lighting.
As far as we know, IES hasn't lashed out at WELL … yet.
Currently the group focuses on lighting, potable water, indoor air quality and comfort, with more wellness-related categories to come.
In the lighting category, WELL looks at 13 characteristics, including circadian emulation, color quality and glare.
More than 1,701 projects, representing 371 million square feet, have received or registered for WELL certifications.
Yet another healthy-building certification out there is Fitwel, which claims to be the “world's leading certification system that optimizes buildings to support health.”
Like WELL, this one covers a wide range of wellness-related elements but there is little emphasis or specific detail on human-centric lighting.
UL: Recommended Practice and Design Guideline for Promoting Circadian Entrainment with Light for Day-Active People
Excerpts from draft report of UL RP 24480, April 29. Open for “public review” through May 28, 2019.
- Mark Rea (Chair), Professor of Architecture and Cognitive Sciences at the Lighting Research Center (LRC) at Rensselaer Polytechnic Institute
- Chris Brown, Nextgen Lighting
- Lei Deng, Current, powered by GE
- Mariana Figueiro, LRC/Rensselaer Polytechnic Institute
- Alan Lewis, Consultant in Physiological Optics
- Adam Lilien, UL
- Terry McGowan, Lighting Ideas, Inc.
- Govi Rao, Noveda Technologies
- Panda Satchidananda, Salk Institute
- Christopher Steele, U.S. Army Medical Research and Materiel Command
- Bryan Steverson, U.S. General Services Administration’s Office of Federal High-Performance Buildings
- Amy Walker, UL
- Karen Willis, NEMA
- Edward Yandek, Lighting Consultant
- The amount of light equivalent to that, after one hour of exposure, capable of suppressing the production of melatonin at night by 30% (CS = 0.30) should be continuously available at the occupant’s eyes for a minimum of two hours during daytime.
- In very simple terms, this translates into a vertical illuminance at the eye (EV) of 350 lx for warm sources and 200 lx for cool sources.
- Step 1: Establish a circadian-effective light design criterion (e.g., CS = 0.3)
- Step 2: Select a luminaire type (e.g., direct/indirect)
- Step 3: Select a light source (e.g., 3000 K LED)
- Step 4: Perform photometrically realistic software calculations for the building space (e.g., AGi32)
- Step 5: Calculate CS from the vertical illuminance at the eye (EV) and the spectral power distribution (SPD)
- Step 6: Determine if the selected lighting system meets the circadian-effective lighting design criterion; repeat steps 2-6 if necessary