Category: Lighting Design

UL Launches Circadian Lighting Field-Measurement Service & Circadian Luminaire Certification

Randy Reid and Katie Smith recently published an article on LinkedIn, about UL’s latest moves into circadian lighting.

Randy Reid and Katie Smith recently published an article on LinkedIn, about UL’s latest moves into circadian lighting. The first new service from UL is a 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. This allows 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 reflectance 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 create 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.

The second service is their Circadian-Effective Luminaire Performance Certification. In this program UL develops a custom testing and certification program to support a manufacturer’s verifiable marketing claims.

You can read the full article here.

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Emergency Lighting That Preserves Architectural & Interior Design Integrity

Discovered at LightFair 2022 – Concealite -The company specializes in emergency lighting and other building life safety equipment designed to disappear into the wall until there is an emergency.

One of my more interesting finds at LightFair was Concealite’s booth. An example is their 5000 Series Emergency Lighting, which includes a self-contained battery system (see image).

Typical emergency lighting fixtures are obtrusive and interrupt the aesthetic beauty of interior designs. Concealite offers an elegant alternative to “bug eyes”. Only when the system is activated, do the high-powered lamps become visible, rotating 180 degrees to begin operation. The result is a clean, almost invisible installation that does not conflict with building interiors. Additional features include:

  • Units can be customized in the field using paint, wallpaper, or applique finishes.
  • Designed for wall or ceiling installations, including gypsum board, plaster, or acoustical tile.
  • Choice of standard 90 minute, 2 hour or 4 hour operation.
  • Self-diagnostic controls are an available option.
  • Vandal-resistant
  • Listed to UL Standard #924 when installed in accordance to Article 700 of the National Electrical Code.

The company has applied the same approach to motion detectors, offering a discreet and vandal-resistant alternative to visible surface mount detectors. Only when the commercial or residential security system is activated does the detector become visible, rotating 180 degrees to begin operation (image above).

Similarly, the company offers concealed UV disinfecting lighting, fire alarms, and exit signs. To learn more, visit their website here.

 

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The Urgent Need For Resilient Lighting

Resilient lighting can survive and operate during and after natural and man-made disasters. Don’t confuse “resilient lighting” with 90-minute emergency lighting, which is designed to get people out of buildings. Resilient lighting is designed to operate for days – or even weeks – after disasters and is part of a larger Resilient Buildings trend.

I originally published this article in US Lighting Trends, in May 2022. It is republished here with permission.

A scan of recent news headlines reveals the need for lighting that can operate in dire environmental conditions. Last month’s wildfires in New Mexico and Arizona and last week’s “tornado outbreak sequence” that devastated parts of Texas and Oklahoma are just recent examples of why resilient lighting has become an important topic.

Resilient lighting can survive and operate during and after natural and man-made disasters. Don’t confuse “resilient lighting” with 90-minute emergency lighting, which is designed to get people out of buildings. Resilient lighting is designed to operate for days – or even weeks – after disasters and is part of a larger Resilient Buildings trend. The Resilient Buildings market is projected to grow from $82.4 billion in 2020 to $124.8 billion by 2025, at a compound annual growth rate (CAGR) of 8.7% during that period.

The biggest driver in developing resilient buildings is climate change. More specifically:

  • Extreme heat events can spike A/C usage and overwhelm power grids.
  • Extreme cold can cripple power grids in the South.
  • Worsening hurricanes are the most common large-scale power disruption, especially in the Southeast.
  • Coastal and other flooding take out power.
  • Wildfires disrupt power.
  • Tornadoes and other high wind events cripple electrical service.
  • Even drought can threaten hydropower, which has happened in Brazil and is a significant concern in the Pacific Northwest.

The frequency and severity of climate change disasters are both increasing. In February 2021, record low temperatures and record-high snowfalls in Texas caused widespread power outages. More than 4.5 million people lost power, some for longer than a week. More than 150 people died as a result, and the price tag for this disaster is estimated at around $100 billion. In 2020, there were 22 separate billion-dollar disasters, shattering the previous record of 16, according to data from the National Centers for Environmental Information. These included wildfires, extreme storms, tornadoes, hurricanes, drought, and even a derecho (a sustained high wind event), which in August 2020, caused more than $11 billion in damage across the Midwest.

So, what does resilient lighting look like? Resilient lighting strategies can include:

  • Whole building backup power systems, both generators & battery storage systems
  • Solar outdoor luminaires, both off-grid and hybrid-on-grid models
  • Placing electrical conduit and luminaires above the level of the flood plane
  • Portable rechargeable lanterns are popular today for recreational purposes but may evolve into resilient residential lighting. Imagine solar & battery-powered wall lanterns that are removable from the wall for use indoors and outside.

The commercial solar outdoor luminaire market has been growing for years and overlaps with the resilient lighting trend. Dramatic improvements in solar cell, battery, and control technologies have all been simultaneous with enormous LED improvements over the past 10 years. This now enables some solar lights to operate for days on a single day of charging. Sophisticated controls and timers further extend luminaire operating time.

Solar area lights have done well in areas that are difficult or expensive to run power:

  • Parks
  • Bike paths
  • Areas with attractive landscaping, to prevent damage
  • Avoiding trenching, cabling, and electricity costs
  • Can be used for portable disaster response lighting

While most solar area lights are off-grid, there are new hybrid solar-grid-connected luminaires that qualify for utility rebates, plus they can reduce liability from off-grid battery depletion.

A variety of building certification programs are helping to drive resilient buildings & lighting. These include:

  • LEED
  • Living Building Challenge
  • RELi
  • WELL Building Standard
  • US Resiliency Council Earthquake Building Rating System

Late last year, the Illuminating Engineering Society (IES) published a new Lighting Practice, called LP-13, Introduction to Resilient Lighting Systems. “The purpose of this document is to introduce the concept of resilient lighting design – the ability to prepare and plan for, absorb, recover from, and more successfully adapt to adverse events – and explain how lighting systems can support the goals of enhancing the resilience of buildings. The intent is to provide guidance on lighting performance, controls, and the characteristics of lighting equipment for resilient buildings.”

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What If Lighting Designers Created Their Own Project Software?

At LightFair, last week, I had the pleasure of speaking with Mike Bishop, VP of Sales, at Sourcery, based in Toronto, Ontario, Canada. Sourcery is a lighting design project collaboration software platform created by lighting designers for lighting specifiers, reps, and manufacturers.

At LightFair, last week, I had the pleasure of speaking with Mike Bishop, VP of Sales, at Sourcery, based in Toronto, Ontario, Canada. Sourcery is a lighting design project collaboration software platform created by lighting designers for lighting specifiers, reps, and manufacturers. It is a social collaborative platform for design industry professionals to seamlessly collaborate with one another when specifying and procuring products in every phase of a project. It makes the process of selecting and procuring products for commercial construction easier and more efficient.

Sourcery was not created by software people, it was created by and for lighting specifiers:

  • To use modern cloud computing tools to create a single point of truth, for a project, with all information in one spot.
  • To be the birthplace of the digital twin.
  • To simplify product selection by maintaining libraries and custom collections of products to create curated categorized lists, assign to projects, and generate luminaire schedules in a few clicks.
  • To collaborate through a live luminaire schedule that improves the process of specifying lighting products and collaboration during design.
  • To enhance transparency through a project management companion, to make the procurement process transparent throughout all stages of design, budgeting, bidding and construction.
  • To provide a direct connection to products and sourcing new manufacturers.
  • To provide the project specifier full control over who has access to specific documents, schedules, libraries, pricing, and other important information.

More information about Sourcery is available here.

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IESNYC Lumen Award Winners Announced

The New York City Section of the Illuminating Engineering Society (IESNYC) announces the recipients of the 2022 Lumen Awards at the 54th Lumen Gala held last night (June 16) at Pier 60 in Chelsea Piers.

The New York City Section of the Illuminating Engineering Society (IESNYC) announces the recipients of the 2022 Lumen Awards at the 54th Lumen Gala held last night (June 16) at Pier 60 in Chelsea Piers.

“We carry the difficulties of the past two years in our hearts, but we raised our glasses high, along with over 800 Gala attendees, and savored being together, once again,” says Lumen Committee Co-Chairs Clara Powell (Cooledge Lighting) and Adrienne Shulman (ERCO Lighting). “We can’t wait to enjoy the magnificent work that has been created by our New York City lighting community and encourage others to do so too.”

This year, ten lighting design firms received a total of 12 Lumen Awards for their winning projects. The award-winning projects are presented in three categories: The Lumen Award of Excellence, the highest level of recognition for permanent architectural application; the Lumen Award of Merit, in recognition for a meritorious permanent architectural application; and a Lumen Citation, in recognition for an art installation, technical detail, portion of a single project, temporary installation, or other work.

  • In the category of Awards of Excellence, four were presented. Fisher Marantz Stone two awards. One for Little Island, and the second for a Confidential Aerospace Defense / Headquarters; Cline Bettridge Bernstein Lighting Design won for the Stony Brook Medicine MART Building and Children’s Hospital Tower; and Renfro Design Group for the Allison and Roberto Mignone Halls of Gems and Minerals at the American Museum of Natural History.
  • In the category of Merit Awards, five were presented. L’Observatoire
    International won for the Winter Visual Arts Center at Franklin & Marshall
    College; Anita Jorgensen Lighting Design for Manitoga / The Russel Wright
    Design Center; KGM Architectural Lighting for the 550 Madison Avenue Lobby;
    Buro Happold for the Denver Art Museum; and TM Light won for the Bike Barn at The Thedan School.
  • In the category of Citation Awards, three were presented. Sighte Studio won for Light Gowanus; Buro Happold for Terra–The Sustainability Pavilion, and One Lux Studio won for the Deutsche Bank Center Lobby.Over 100 submissions were received and reviewed by the 2022 Lumen Award Jury: Glen Fasman (Principal, Bliss Fasman; Michael Hennes (Associate Principal, CBBLD); Carrie Meadows (Associate Editor, LEDs Magazine), Kelly Roberts (Studio Director, WALD Studio and President, WILD), Claudia Saavedra (Lighting Designer, R.G. Vanderweil); Richard Southwick (Partner, Director of Historic Preservation, Beyer Blinder Belle); and Beth Turomsha (Senior Lighting Designer and Studio Leader, Schuler Shook).

A signature program of the IESNYC, the Lumen Awards, and Gala, showcase and celebrate excellence in lighting design. The Gala, billed as the “lighting event of the year,” was on hiatus for the past two years due to COVID. The recipients of the 2020 and 2021 Lumen Awards and their winning projects, previously announced online, were also acknowledged and feted at this year’s Gala.

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Product Monday: Sourcery Software Is Lighting Specifier Collaboration Platform

Sourcery is a social collaborative platform for design industry professionals to seamlessly collaborate with one another when specifying and procuring products in every phase of a project.

Sourcery is a social collaborative platform for design industry professionals to seamlessly collaborate with one another when specifying and procuring products in every phase of a project. The software makes the process of selecting and procuring products for commercial construction easier and more efficient. Sourcery uses modern cloud computing tools to create a single reference location with all information in one place.

The platform:

  • Increases Efficiency – Through maintained libraries and custom collections of products create curated categorized lists, assign to projects, and generate luminaire schedules in a few clicks.
  • Encourage Collaboration – Through a live luminaire schedule that will Revolutionize the process of specifying lighting products and collaborating during design.
  • Enhances Transparency – Through a project management companion to make the procurement process transparent throughout all stages of design, budgeting, bidding and construction.

Learn more here.

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How Dim-To-Warm Lighting Works

An article in Lighting Exchange breaks down how Dim-To-Warm lighting works. Warm dimming can also be referred to as dim-to-warm or black-body dimming.

An article in Lighting Exchange breaks down how Dim-To-Warm lighting works. Warm dimming can also be referred to as dim-to-warm or black-body dimming.

Dim-to-warm simulates an incandescent ambiance by adjusting the LED color temperature as you dim. This type of lighting can be dimmed down to a relaxing amber tone, similar to that of a candle.  It provides the same warmth and glow as halogen dimming performance.

It is typically designed for 2700-3000 (Kelvin) at full output and decreases in correlated color temperature (CCT) as the output is reduced.  This output can go down as low as 1800K (the color of candlelight). The light color becomes increasingly warm in appearance (more yellow and red) as the product dims.

Light color and the dimming quality of fixtures are highly valued in hospitality settings such as restaurants, hotel lobbies, guestrooms, ballrooms, and theaters.  It is also an excellent addition to any residential space.

Dim-to-warm’s methodology can accentuate any area and bring out its best features.  The warm-colored lighting can create the desired look and feel that hospitality managers want their customers to experience.   The light is reminiscent of the warmth of home and can be an effective way to provide a calm, relaxing atmosphere for clientele.

Dim-to-warm lighting requires at least three LED primaries to dim along the black body curve like incandescent lighting. This type of product’s dimming is associated with the color change; therefore, there is only one control signal and, consequently, only one controller per group of luminaires that dim in unison.  Some systems can accomplish this function with a phase-cut dimmer, where the dimming information is carried in the voltage waveform.  This tactic may not have as much dimming resolution or smoothness as a control system using 0-10V, DALI, or DMX. The latter three require separate wiring for the intensity/color signal and luminaire power. Dim-to-warm luminaires can be equipped with a wireless receiver for control by a wireless transmitter using Zigbee, Wi-Fi, Bluetooth, or hard-wired to facility power.

Read the full article here.

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Trends In Flexible Lighting Design

Howard Yaphe, CEO of Axis Lighting, authored an interesting article in EC&M Magazine, recently, about trends in flexible lighting design.

Howard Yaphe, CEO of Axis Lighting, authored an interesting article in EC&M Magazine, recently, about trends in flexible lighting design. Conventional drop ceilings are being used less, in favor of more dynamic and adaptable office lighting solutions.

Open ceilings make a space look larger and better future-proof a design.  This approach can include line-voltage frameworks that create more design freedom for specifiers. The increased flexibility can aid offices in transitioning to post-pandemic trends of more flexible office usage.

Read the full article here.

 

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Five Lighting Designers Discuss The Latest Trends In Lighting Retail Spaces

A recent IES LD+A article interviews five lighting designers about the trends that they see in lighting retail spaces.

A recent IES LD+A article interviews five lighting designers about the trends that they see in lighting retail spaces.

Some trends include:

  • Explosion of e-commerce during the pandemic and the extent to which people will go back to retail.
  • E-commerce went from 5% of retail sales in Q1, 2012 to 16% in Q1, 2020.
  • Retailers who had paused their new prototype strategies in 2020 and 2021 with the unknowns of the pandemic, now in 2022 are dusting off those designs and moving forward.
  • The in-person experience is adapting rapidly to accommodate a wide variety of shopping styles, and the lighting systems must change to create enhanced brand experiences.
  • Retailers are expecting shoppers to return in-store in substantial numbers, especially for non-commodity goods and experiential services, including electric-car companies, jewelers, pet-care companies, salons, grocers, outdoor-gear companies, apparel and footwear.
  • Regional shopping centers adapting toward mixed-use destinations, where people are drawn in by restaurants, fitness centers, theaters, hotels, open-exterior spaces and other amenities intermixed with retail. Lighting becomes integral to creating an atmosphere—drawing visitors in and encouraging them to explore.
  • Stores are catering to “Instagrammable” moments. The architectural design includes areas that look great on camera, so the lighting needs to be soft for camera use, too.

The full article is available here.

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NEMA Luminaire Section UGR Task Force Chair Jeremy Yon Talks Glare Metrics

I recently had the opportunity to interview Jeremy Yon, Industry Relations Leader, GE Current, a Daintree company, and Chair of the NEMA Luminaire Section UGR Task Force, on the topic of application of the Unified Glare Rating (UGR) metric. Transcript follows.

I recently had the opportunity to interview Jeremy Yon, Industry Relations Leader, GE Current, a Daintree company, and Chair of the NEMA Luminaire Section UGR Task Force, on the topic of application of the Unified Glare Rating (UGR) metric. This interview was conducted to inform an article that will be published in the September 2022 issue of ELECTRICAL CONTRACTOR, the official publication of NECA. Transcript follows.

DiLouie: NEMA recently published LS 20001-2021, a whitepaper concerning current use of UGR as a glare metric. What was the rationale behind producing this whitepaper?

Yon: Glare is a timeless and universal concern to everyone who cares about lighting. It is one of the most critical aspects of an occupant’s experience with lighting and one of the most devilishly difficult topics. Historically, glare comes in and out of fashion. Because LED efficacy is now slowly increasing, glare is returning to the forefront of the industry’s attention. This topic has been grappled with by true lighting visionaries in the past, and now my NEMA colleagues and I are attempting to re-structure how glare is thought of and talked about so that there can be a common understanding and vocabulary when working together with all stakeholders.

DiLouie: What does UGR, overall and in general, reliably deliver, and what are its limitations?

Yon: The broad aim of UGR is to provide a better way to evaluate glare in indoor settings. However, it is not a simple matter because UGR depends strongly on the specific application; not only in regards to the luminaires, but also in their layout, the shape of the room and the reflectances of the surfaces in the room all affect the value of UGR. Additionally, the location of people in the room and the tasks conducted within the room can affect the experience of glare as well, so different values of UGR may be desired in different applications.

Therefore, we believe much of the confusion and misunderstanding when it comes to UGR is due in part to the three different ways that the term is used – they each have their own purposes and limitations. Since they were unnamed previously, we’ve taken the liberty to recommend that they be called Application UGR (UGRAppl), Luminiare UGR (UGRLum), and Point UGR (UGRPoint).

We’ve come to understand through our research that Application UGR and Point UGR can be tools for lighting designers to get predict what will likely be the visual comfort level for specific locations within an application. These are not absolute determinations and must be balanced with other predictive factors. Application UGR was designed while, and works best when, considering a windowless rectangular room with regularly spaced luminaires (think troffers). Point UGR is possible with computer simulations, but it should not be evaluated by looking at each point as it requires averaging over an area by the user to achieve the intended indication of comfort.

Luminaire UGR is the most common use of the term today and is the most problematic use of the equations. The UGR methodology was not intended to be an absolute measurement. The Luminaire UGR approach does this by forcing an evaluation of a single luminaire type in a specific evaluation space without taking into consideration the space itself (geometry, room finishes, luminaire placement, windows, partitions, multiple luminaire types, etc.). It cannot appropriately predict the likelihood of glare in any space other than that single specifically required condition. NEMA advises strongly against using Luminaire UGR.

DiLouie: What are the most common misconceptions practitioners have about glare and UGR, and what is the reality they should understand?

Yon: I think the most common misconception is to assume that a luminaire can have a UGR rating, ignoring the role of the application. If you look at a table of values produced by the tabular method for a single luminaire, you will see that, depending on the light distribution of the luminaire, the UGR can vary greatly. It clearly does not depend only on the luminaire. Below is an example in which UGR varies from 2.6 to 21.8.

While some may claim that UGR is the best of the various limited glare evaluation tools, that doesn’t mean UGR can deliver more than it is capable. Unless properly evaluated for the specific application in which a luminaire will be used, it can’t give absolute assurance that the luminaire selected is going to meet the required lighting design criteria. To this point, some manufacturers refuse to put Luminaire UGR numbers on their cutsheets. They don’t want to contribute to a misuse of the UGR metric, nor have their customer be the victim of poor lighting design quality because of a misapplied UGR number.

DiLouie: DLC, LEED, and WELL specify a maximum UGR based on glare emitted by the luminaire (UGR-Lum). This offers an advantage of reducing glare to a simple number published on a catalog sheet. NEMA says there are significant disadvantages. What are they?

Yon: All of those rating programs use the Luminaire UGR simplification to get the single value you mention. This creates a situation where a designer thinks they are selecting a product that has the “right number,” but in actuality, they may be selecting one that has more glare than is desired in application. From the example given earlier, the tabular reporting of that luminaire had a range of values from 2.6 to 21.8 – just based on room size and no other factors. With a variation this wide, it simply makes no sense to try and represent a luminaire with a single number.

Because of the selection of only a single reported value, there are many factors that impact the visual experience found in the final application that are not incorporated into Luminaire UGR. Some examples include the room finish (a dark ceiling will be much different than a light ceiling), the luminaire mounting height (high-bay vs office), and non-uniform placement (troffer grids vs artistic slots).

At the same time, luminaires that are designed to achieve only a Luminaire UGR value, and not to minimize glare from an application approach, can have various consequences. The luminous surfaces of the luminaires may be less uniform with easier-to-see LEDs, there may be additional accessories that need to be installed and there may be a feeling that the final spaces are darker, even though there may be adequate horizontal light (some may remember the deep-parabolic troffer days of the 1980s).

DiLouie: NEMA believes UGR-Appl, adopted by ISO and EN 12464-1, is a more appropriate metric to use to predict glare in a space…

Yon: NEMA is saying that UGR should be used in the way intended by the original CIE documents. Simplifying it to a luminaire based value is not correct.

DiLouie: Some organizations utilize UGR-Point, which predicts glare at a point in the space. This similarly places the metric in the space, not at the luminaire, but NEMA cautions about its use. Why?

Yon: Simulations will produce an array of point UGR values in a space. The original UGR uses a “trick” to calculate the average UGR over a 1H x 1H square centered along the walls. If only point calculations are done, as simulation software typically does, then the averaging step is omitted. Judicious positioning of the luminaires and/or the point for calculation can result in large variations in the UGR. “Cherry picking” from a set of UGR point values can yield a misleading value for UGR.

In examples given in the NEMA paper, UGR tables include a variation expectation that is often overlooked. These show expected point-to-point variation values, depending on the spacing of the luminaires. In the example we provided, the variation ranges from a minimum of +3/-3 units to +7.5/3.8 units, making a comparisson against a threshold impossible.

The user of a piece of software should perform proper averaging, either as detailed in the UGR standard (in a 1H x 1H region at the center of two adjacent walls) or in certain situations where occupants are only in specific areas, such as custom areas that best represent their design objectives. Secondly, there are some ambiguities in the UGR standard around handling different sizes of luminaires that can lead to differences between software simulations.

Finally, and most importantly, the designer needs to balance the results with all the other aspects of a lighting design – vertical illumination, presence/design of windows, space use flexibility, circadian exposure objectives, etc.

DiLouie: If UGR-Appl is most advantageous in predicting glare, a challenge is that the procedure appears to be complex and not well understood. What is the solution for this?

Yon: It is complex and not well understood! The fundamental CIE UGR standard (117) has been around since 1995. But oversimplifying it will lead to artificial selection of some luminaires as “good” and others as “bad,” when in fact the goodness/badness is impossible to evaluate outside of the context of the application. With the absence of a simple answer, it is good for all of us to remember that lighting, by definition, is a blending of art and science. This balance is what makes it so interesting and engaging for most of us.

The first recommendation is that luminaires should be used in the manner in which they were intended; if a high bay luminaire is used in an office, there is probably going to be a difference in visual comfort than if a luminaire designed specifically for an office is used. Building on this notion, manufacturers play an important role in determining what appropriate use is. The literature should be clear, and specifiers should ask for details they feel will help complete the project. A qualified lighting professional should be used to bring together all the complexities of lighting into an optimized solution.

Finally, and most importantly, all stakeholders need to come together with researchers to provide consistent and actionable recommendations. The IES is tackling this for some product categories and there is hope for continued engagement. Internationally, there is still work to be done by the CIE.

DiLouie: How should electrical contractors evaluating lighting systems approach it in regards to ensuring a product will not produce objectionable glare? Are there rules of thumb for evaluating application glare?

Yon: The most important rule of thumb is that glare, at its essence, is related to the difference between a bright object and a dark background. This is easy to see in daily life – high-beam headlights that can be disabling at night are barely visible during the day. The first step is to factor in the surfaces around the luminaire – are they light or dark finished? Is there light from other sources hitting the surface to keep it from being dark? The luminaire should fit into those needs by providing diffuse light in circumstances where an overall lighter environment is warranted, controlled and shielded when a dark atmosphere is expected.

It always helpful to think of the extremes – a soft white uniformly backlit luminous ceiling and white walls (if not overly bright) can have almost no glare (to the point that it can be disorienting); whereas a black-box theater goes to extremes to hide the source of the light so as to not draw attention away from the performance. Similarly, luminaires for offices would most likely be expected to have a uniform appearance and contribute to lighting the walls and surfaces, while task-specific lights (such as a wall-wash or a high-bay warehouse aisle light) rely on precision optics that need to be coordinated with the overall viewing expectations of occupants.

DiLouie: What other solutions does NEMA recommend as a way to ensure lighting systems are designed and delivered that minimize glare while serving the best needs of the application?

Yon: The first is to recognize how UGR can be both properly and improperly utilized as a guidance method for good lighting design. We’re hopeful that through the NEMA whitepaper, it is understood that only Application UGR provides suitable guidance in terms of what an occupant will experience in a specific space. In addition, if simulations are done, the individual point UGR values should not be utilized (averaging should be done) and there are assumptions about large and small luminaires that may lead to variations of answers in different software platforms.

Certainly, there is more study and work to be done to improve how we predict glare. It is hopeful that further focus and effort can be made that will simplify how this is done. Yet for now, Application-UGR remains our best option. What we don’t want is a misunderstood lighting metric, such as Luminaire-UGR, being used in good faith efforts to simplify the situation, as this will result in poor outcomes in lighting performance.

DiLouie: If you could tell the entire electrical industry only one thing about UGR, what would it be?

Yon: Our message to the industry is that UGR is an imperfect predicter of glare, but Application UGR is the best method we have today. With the right understanding, it can be an asset to lighting design application. If UGR’s limitations are not understood, such as using Luminaire UGR as a singular number inaccurately across a variety of applications, it undermines the purpose of the metric and can result in poor lighting.

DiLouie: Is there anything else that you’d like to add about this topic?

Yon: NEMA members place a high value on the visual environments our luminaires create. We work together with designers, installers and users to balance the needs of an application to create the most appropriate experience. Balanced factors like efficacy, color rendering, color temperature, uniformity, light distribution, color consistency, etc. all can have different impacts on the perceived glare for each specific application that cannot be factored into a single-value luminaire value.

NEMA welcomes the opportunity to work with all the stakeholders in evolving means to both predict and communicate expectations for visual comfort. Today, Application UGR and averaged Point UGR calculations can be an effective part of an overall lighting design, but they are very limited and should not be applied as a luminaire selection tool.

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