24 APRIL 2019 COMMERCIALARCHITECTUREMAGAZINE.COM
on time of day, such as cool during business luncheons to
warm during evening dining.
In HCL, the greatest value of dimming and color con-
trol may be found in circadian lighting design. Scientific
research has shown that specialized photoreceptor cells in
the eye are connected to circadian functions, and has
identified spectra, quantity of light, duration, and timing
capable of producing circadian stimuli. From this under-
standing came actionable approaches to design, with
good circadian design typically focused on:
- Spectral distribution, or saturation of specific wave-
lengths in the visible-light spectrum that we typically as-
sociate with the light being warm or cool in appearance.
Circadian regulation is most responsive to short-wave-
length light (460 nm), which is in the blue range of the
visible spectrum). - Spatial distribution, which defines where the light
emitted by a luminaire falls in the observer’s field of view
(FoV). For circadian response we want a sufficient quanti-
ty of light on the upper quadrant of the environment for
sufficient periods of time during the day. Equate this to
the outdoors, where the sky occupies the top section of
our FoV. This requires vertical illumination (uplighting
walls and ceilings, or workstation luminaires), in addition
to the standard work-surface-targeted lighting devices. - Temporal distribution, which simply means the right
light (in terms of CCT and intensity) at the right time of
day. A circadian lighting solution ideally exposes users to
high-intensity, short-wavelength-heavy light in the morn-
ing, which can taper to lower light levels of long-wave-
length light in the afternoon.
Daylight is ideal, though it is not always available, and
the electric-lighting system can work with daylight for an
optimal solution.
Finally, this brings us to standards. Best practices for
circadian lighting are still emerging, such as International
Standard DIS 026/E:2018, which is being considered by
the International Commission on Illumination, Vienna,
Austria. This standard would define spectral sensitivity,
quantities, and metrics to describe light radiation for its
ability to stimulate each of the five types of photoreceptor
cells in the eye that produce non-visual effects in humans.
One standard that is oriented toward application and
actionable today is WELL, a rating system focused on
evaluating how effectively a building supports human
health and wellness. Launched in 2013 by the Internation-
al WELL Building Institute, New York, this rating system
awards points for various building features and practices.
This includes lighting, notably circadian lighting, visual
comfort, glare control, color quality, automatic dimming
and shading, and daylighting.For circadian lighting, WELL establishes four types of
environments and requires a minimum level of light capa-
ble of producing circadian stimulation. Measured at the
eye level, this light is measured as equivalent melanopic
lux, an alternative metric to footcandles/lux that is weight-
ed to non-visual photoreceptors.
A key enabler for HCL strategies is lighting controls, a
segment of the lighting industry undergoing its own digi-
tal revolution. These are the sensors, controllers, apps and
programs, and communication technologies that enable
manual and automatic control of light and color output.
Because LED lamps and luminaires are already elec-
tronically controlled, they are inherently compatible with
intelligent systems capable of sophisticated control and
data collection from sensors. Using this data, operators
can optimize energy cost savings while gaining valuable
insights into user lighting preferences and satisfaction.REALIZING HCL
What does this mean for designers? Rather than a fi xed
utility used to produce the commodity of light, lighting
has become an asset offering far greater value. There is
no single lighting solution that is ideal for every client
and application. What leading commercial architects and
designers are doing is looking beyond traditional design
thinking and changing the conversation they’re having
with their clients.
This requires education that, in turn, will fuel a differ-
ent conversation about lighting—not one limited to light
levels and watts, but one that incorporates all of lighting’s
current possibilities and best practices. From color tuning
and dimming, to more effective ways to light spaces, to
data collection, today’s lighting technology, application,
and thinking has taken the category far beyond its static
traditions, with more value on the table than simple
vision. CAAlberto Pierotti is head of R&D and Smart, USC at LED-
VANCE, Beverly, MA, makers of Sylvania general light-
ing products in the U. S. and Canada. He is leveraging the
company’s century of expertise in light to chart the path
into the intelligent, distributed-lighting systems of the fu-
ture. For more than 20 yr., Pierotti has been involved in
every step of the product-development process in fields
spanning medical devices to capital equipment, and from
wearable consumer electronics to architectural lighting.PROJECT|lighting & electrical
- LightingEurope, lightingeurope.org
- International Association of Lighting Designers, iald.org
- A.T. Kearney, atkearney.com
- International Commission on Illumination, cie.co.at
- International WELL Building Institute, wellcertifi ed.co
Want more information from LEDVANCE, Beverly, MA (ledvance.com)? Circle 7 on the Reader Service Card.
Sources listed below are linked at commercialarchitecturmagazine.com/1904ledvance.According to the “SSL-erate” European Union project, exposure to light similar to natural daylight at the right time can help improve the mood of residents
in retirement and care homes as well as patients in hospitals, helping prevent depression and reducing anxiety in patients in the early stages of dementia.