Design for Dynamic Light
By Craig Casey, Senior Building Science Engineer, Lutron Electronics
To a certain extent, we can all take lighting for granted, but especially in commercial architecture, LED lighting can be truly dynamic, enabling virtually infinite variation in color temperature, color rendering and saturated color.
By dynamic light we mean light that can change to best suit a space, including shifts in color temperature and intensity, or even adjustments to color spectrum to deliver an environment that reflects the natural progression of daylight over the course of a day. There are several ways to achieve dynamic light with lamps and control solutions that provide warm dimming, tunable white, and/or color-changing capabilities.
Achieving Dynamic Light – Understand the Needs of the Space
Dynamic light can help provide more human centric, comfortable, and flexible spaces, and this is not a one-size-fits-all proposal. First, you want to determine whether you need dynamic light by asking a few key questions about the space:
Dynamic lighting contributes to spaces that are comfortable, flexible, and more human centric.
Photo credit Magda Biernat
Will there ever be …
… a desire to enhance the connection to the outdoors with lighting that mimics daylight?
Consider open office environments where natural light is a highly desired amenity.
… a desire to use color to modify the mood or the impression of an environment?
In restaurants, lounges, and bars, for example, lighting often changes over the course of the day. – bright and energetic earlier, while late night lighting encourages people to relax and spend a little more time.
… a concern about interior design changes that will alter your choice of light spectrum?
Spaces such as hotel lobbies, interactive classrooms, ballrooms, and auditoriums benefit from lighting that can quickly accommodate a new event or help improve “curb appeal.” Dynamic lighting sets the stage for spaces that can be easily updated without expensive rewiring or major renovations.
Can light spectrum dramatically affect the impact of products, artwork, or other visual elements, and do those elements change frequently? Museums, hotel lobbies, restaurants, retail areas and community spaces can all use color to create emphasis, guide a visitor, highlight a piece of art or merchandise, or invoke a desired mood, setting, or feeling.
Identify the Right Type of Dynamic Light
Next, you can dig a bit deeper to determine what type of dynamic light is best for a given space or building – warm dimming, tunable white, or full-spectrum.
Tunable white lighting provides a broad spectrum of options for any space.
Warm dimming – If all anticipated uses of the space fall into either full, bright light (for example setting up or cleaning a space) or dimmed light to promote a warm, relaxing environment, warm dimming may be sufficient.
Tunable white – In spaces where connection to the outdoors is important, or where light can enhance the mood of a space, you may specify tunable white. Tunable white, which enables independent control of CCT and intensity, will provide ample flexibility for achieving the right light over the course of a day.
Full spectrum – Help take your spaces to the next level with the ability to alter color without limits, recall pre-programmed lighting sequences, seamlessly mimic natural light, and infinitely adjust lighting over the course of an event, a day, or a season.
Depending on the system you choose, you can mix and match control protocols within the same system, using the right type of control in the right space without compromise and staying within budget.
Good Design Starts with the Client Interview
Designing lighting to meet all the needs of a given space also starts with a series of questions – the client interview.
Consider the fixtures that will be used on your project, match the fixture type to the desired performance of the light, and then begin the client interview. The interview takes time and patience but is also the key to in-depth understanding of how a space will be used, how people will interact within the space, and how the lighting can enhance space performance.
As an example, we’ll examine a hospital patient room. The goal of the interview is to define, write down, and mentally walk through each scenario to help identify potential conflict and understand the appropriate sequence of operations within each scenario.
Start with a client interview to document the difference scenarios that will take place in each space.
Photo © Halkin Mason Photography
Consider the default lighting schedule, whether the space will need to mimic daylight with color temperature and intensity changes throughout the day, and how manual overrides will be used over the course of the day.
If you are recommending tunable white, ask about the desired color temperature range (2700K – 5000K is typical indoor CCT, but dimmed incandescent can go as low as 1400K, and blue sky can be in excess of 10,000K). Visualize the lighting transitions and discuss these with the client – in this case the facility manager and medical professionals who will use the space. Also, ask about including keypad engraving to make scene selection intuitive.
A typical client interview for a patient care space
Regardless of the type of space, this important, up-front planning will reveal the extent to which the lighting will have to accommodate the client’s needs and will equip you with the information you need to deliver a complete lighting design proposal.
Scenario – Daily Care
From 6am to 10pm patient downlights set to medium, CCT follows daily cycle
From 10pm to 6am patient downlights set to low, CCT follows daily cycle
Patient care staff needs 24/7 access to lighting override to adequately check on patient. Access at different times of day require different light levels, but CCT can follow daily cycle. Patient care provider override will feature higher levels during the day, and lower levels at night, lasting for 15 minutes.
Scenario – Patient Exam
During Exam override, patient room lights set to a medium light level. Lights over the bed are set to bright level. CCT follows daily cycle.
During Exam, patient care staff needs higher light level regardless of time of day, patient controls will be disabled, override lasts one hour
Scenario – Patient Emergency
During Emergency override, patient room lights and lights over bed are set to bright level, and CCT is a constant 5000K
During Emergency exam, patient care staff needs higher light level regardless of time of day, all other keypads (patient and any wall controls) will be disabled, override lasts until staff member presses the assigned emergency keypad to avoid any accidental light change
Scenario – Patient Control of Lights
Lights are not scheduled to predetermined changes based on time of day.
Patient keypad turns all lights ON or OFF, and adjusts and lowers headboard light, and can change the CCT of the color changing luminaire
There may be Exam override, or Emergency override controls for the patient care staff
Additional scenarios may include a patient’s family visiting, multi-patient situations, or a patient who needs something in the middle of the night like a restroom, drink, etc.
Lighting scenes can be present to meet specific patient scenarios.
The same interview and documentation process should be used in any situation to understand scenarios in an office, a classroom or school, a commercial shift work operation, and so on.
Once scenarios have been visualized and the SOO considered, separate fixtures into appropriate control zones, consider labeling conventions, and document the controls narrative with specifics: reference actual zones, actual lighting levels, and do so for each keypad.
Labeling conventions for each control can simplify scene recall.
Controls are Essential to the Preferred Lighting Strategy
Specify the control solution that best ensures you can implement your preferred lighting system strategy. A tunable white system that allows individual control of both lighting intensity and CCT will give you the greatest freedom to deliver quality light, and a digital solution provides the greatest flexibility to set up the lighting for current needs, and then easily adjust zones, scenes, and fixture assignments when the space use changes.
Currently, for example, 0-10V control solutions can meet some aspects of a design spec, but do not offer robust tunable white, and there is no way to easily rezone lighting or control updated driver technologies – digital, software upgradable solutions can enable both.
Careful planning for dynamic lighting that meets both today’s and tomorrow needs is a detailed, time-intensive process, but in the long run it will deliver a space that is flexible, built to enhance the human experience of the space, and capable of easily pivoting as newer technologies are introduced and situations inevitably change.