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Understanding Lighting Controls

Lighting Controls

By Craig G. Malesic, PE, LC, PMP

In our recent blog post about Lighting Trends, Thomas Schubert and I shared that lighting control systems are becoming very complex, the “why” is too often being ignored, end-users don’t understand the controls, and the lighting is often not properly commissioned. However, since ever-changing building and energy codes are driving the increased application of advanced lighting controls, I wanted to follow-up the trends blog with an overview of the various types of lighting controls.

Groups like the Illumination Engineering Society of North America (IESNA), the American Heating, Refrigeration, and Air-Conditioning Engineers (ASHRAE), and the International Code Council (ICC) create the various energy codes that have been driving adoption of advanced lighting controls.  Specifically, the International Energy Conservation Code (IECC) and AHRAE/IESNA 90.1 are the enforced codes that determine the requirements for an energy-efficient design. These codes and guidelines dictate which types of controls must be used and how they must be configured. The primary purpose for the lighting design codes is to minimize energy used by selecting energy-efficient sources and to eliminate wasted energy by either turning off lights that have no reason to be on or dimming the lighting when appropriate. As the design and construction industry continues its march toward the goal of net-zero energy use in buildings, codes are doing their part by mandating increasingly stringent rules. With each subsequent code update, we see ever-decreasing allowed connected lighting wattage requirements. The good news is that sources such as LEDs use less total wattage per light output, existing design practices often result in over-lit spaces, and occupants easily adjust to lower levels of lighting.

Even with these increased requirements, not all spaces and applications are treated equal. Within codes there are exceptions included for specific cases. Because of safety concerns there are some applications where lighting controls could potentially lead to injury. The code is sensitive to this and provides a exception for potentially hazardous control schemes in these areas.  For instance, a worker in a mechanical and electrical room doesn’t want the lights to automatically shut off while they are working on an energized electrical panel. A well-designed system does not provide this typical energy saving feature, but an inadvertent failure or poor design not taking these realities into account could be catastrophic. Another example would be a manufacturing or machining operation that has many moving parts, and therefore a risk associated with the space suddenly becoming dark.  The code also allows exceptions for controls where security is an issue but is understandably vague.  Because a reasonable argument can be made that application of a code in a particular area could pose a danger, it is generally accepted by code reviewers to forgo controls in these areas.  In each of these situations, a designer needs to be careful where an exception is made and be prepared to present a reasonable case if questioned by the Authority Having Jurisdiction (AHJ).

Because of the many types of lighting controls available today, we’ll cover the options in a series of posts. This is not intended to be a design guide (that’s why you hire a professional lighting designer!), but rather an overview of the types of lighting controls, how they work, and basic applications. We will go beyond the often-used concept of “just” putting in an occupancy sensor. They certainly have a place, but I would like you to be able to navigate a well-thought-out lighting control scheme that may make more sense. To do this, you need to understand the options.  I am a big believer that complex things can be simplified for all to understand and will attempt to remove the mysteries of the various ‘magical’ devices that we use every day.  It may get slightly technical, but only at a general level.  While you may never be called upon by a manufacturer to utilize the newest release of their lighting control product, it is still good to have a base understand of how it works.

The types of lighting controls that will be covered include:

  • Occupancy Sensors
  • Vacancy Sensors
  • Dimmers
  • Daylighting
  • Integrated Controls (within light fixtures)
  • Room Controllers
  • Scene Controllers
  • Whole Building Systems / Campus Wide Systems

There are codes related to each of these options, which we’ll cover as well.

Before we get started, your “homework” is to check out these other blogs, which will provide some foundational knowledge for our new series:

Lighting Trends: Everything is Changing, But Not Everyone is Keeping Up

Understanding Correlated Color Temperature

What is the Ideal Color Temperature for Your Lighting?

Illuminance and Perceived Brightness

Understanding Selectable Color Temperature

Ready to get started? In our next post, we’ll focus on the first three types of lighting controls:

  • Occupancy Sensors
  • Vacancy Sensors
  • Dimmers

Have questions about lighting? Looking for a professional lighting design team for your next project? Check out JDB Illumination and reach out to me at cmalesic@jdbe.com or 717-434-1559.

Connect with Craig

Understanding Selectable Color Temperature

 

Selectable Color Temperature
by Thomas G. Schubert, PE

The lighting industry today is becoming saturated with talk of numerous new technologies, how they will enhance our lives in passive ways, and why we should buy into the hype. One such technology being pushed is selectable color temperature – the ability to program interior lighting fixtures to mimic the way the sun goes from a warm red in the morning to a cooler blue in the middle of the day and back to the warm red at sunset. Research dollars are being spent to better understand our circadian rhythms and how lighting affects these natural flows; marketing dollars are in turn being spent to tell us that it’s all about the lighting.

The questions being asked, and the answers they provide, will impact the generations to come. How has the shift to cooler fluorescent interior lighting affected our well-being? Is there a better way to light our interior spaces? Where should we be mimicking nature in order to regulate our natural rhythms? What are the lighting design best practices for well-being?

Two Types

First let us dispel some potential confusion. There are two types of adjustable color temperature LEDs on the market today: those that shift to the lower temperatures when you dim, referred to as “warm glow” or “warm dim,” and those that are adjustable at any intensity, which are referred to as “selectable color temperature.” The difference comes down to complexity. Do you want your LEDs to dim in a fashion similar to what you experienced with incandescent lights without having to worry about more nobs and dials? If so, pick a warm dim LED. However, if you want complete control over when the light is warm and when the light is cool, add a second dimmer or control module and go with the selectable color temperature.

Why is this even a thing?

The most efficient LEDs, in terms of lumens per watt, are a solid blue. Over the past few decades, manufacturers have been creating ways to adjust this color to emit more white through the addition of phosphors. However, when you add this layer of phosphor, the amount of light that comes out of the LED decreases. The balance has always been adding just enough to get the right color.

Incandescents were created and function in an entirely different capacity. They take a current and pass it through a thin metal string, called a filament, which glows as it heats up to produce light. When we reduce the current being sent through this metal its glow dims but, as with all fires, this dim fades towards the red spectrum.

This is one of the fundamental disconnects between LED and incandescent lights. Dim an LED and the light temperature remains constant. Dim an incandescent and you get this nice rich, red glow. Manufacturers wanted the efficiencies of LEDs, but didn’t want to give up this feature, so they created selectable color temperature lighting.

How it works

An LED light fixture typically comprises multiple LEDs on a single board. The light from these LEDs is usually mixed either with a lens or with a remote phosphor – or through the lighting fixture construction – to soften the individual pinpoints of light. To produce selectable color temperature lighting, manufacturers have added two or more colors of LEDs onto a single board. For example, cool and warm light. Then, depending on the requested temperature, one set of colors dims as the other set intensifies in order for the mix of the two colors to produce the requested temperature.

This method doesn’t come without its drawbacks. The first limitation is light output. Twice the number of LEDs are required on a board in order to allow the range of options, with one group either completely off or the two groups dimmed in such a way that the light’s intensity doesn’t fluctuate. Another limitation is a loss of efficiency. The lower color temperature lighting requires more phosphor, leading to less lumens out per watt. Finally, there is an increase of control complexity, with each control station requiring two dimmer switches: one for color and one for intensity.

Where they should be used

I have had clients ask for LEDs to be retrofitted into their existing spaces, only to come to hate the cold feel the LEDs provide. When I hear this feedback, it is really the clients commenting on how they enjoyed the warmer temperatures when the lights were dimmed. Warm dim or selectable color temperature should be used where a client desires to maintain that ‘incandescent’ feel and doesn’t mind spending a few additional dollars on their electric bill.

Another application for selectable color temperature is where specific colors must be created, such as when highlighting a business logo or displaying clothing or fabrics for sale. The eye sees colors differently depending on the conditions, such as source lighting, which provides flexibility in the commissioning of these highlight lighting fixtures to avoid any future headaches. Dialing in the color temperature to get that exact shade of red can be very satisfying. Note that selecting a lighting fixture with a high color rendering index (CRI) improves how all colors will look and should be seriously considered when used in this application.

Lastly, selectable color temperature can be used in spaces where human productivity and well-being is of the highest priority. Hospitals, care facilities, even office space with an aligning corporate culture are ideal areas to upgrade the lighting package and dial in the specific color temperatures. Commissioning is important in these applications. If the shifts in color temperature are fixed throughout the day, such as to mimic the outdoor environment, they should be programmed properly to get the most out of the system. If the client wishes to tweak the settings, training is a must so that they use the system properly – now and in the future.

Conclusion

Selectable color temperature lighting fixtures are important tools for a lighting designer but should be used for the proper application. When they are combined with natural daylight, holistic facility management strategies, and functional lighting design, they can transform our interior spaces into comfortable, healthy environments for all.

Questions about selectable color temperature lighting? Learn more about JDB Illumination and contact Thomas Schubert, PE, at 717.434.1554 or email him at tschubert@jdbe.com.

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Illuminance and Perceived Brightness

Understanding Correlated Color Temperature (CCT)

What is the Ideal Color Temperature for Your Lighting?

Illuminance and Perceived Brightness

Illuminance & Perceived Brightness

By Craig G. Malesic, LC, EIT, PMP

Have you ever walked into a room and thought “Man, it’s dark in here!” As a lighting designer, when this happens I typically ask, “Is it really dark in the room, or does it just seem dark? And, if it just seems dark, why?”

To understand this, we first need to understand the relationship between illuminance and perceived brightness. Illuminance is the measurement of the amount of light falling upon a given surface area. When we measure foot candles on a horizontal plane, we are measuring illuminance.

Perceived brightness, conversely, is how the human mind observes, evaluates, and procesess the illuminance that we see in a room.

A good example of this can be found in the average residential garage. Many garages have one A-19 bare bulb lamp installed in each car bay. Often it is nothing more than a 100W, A-19 incandescent lamp. Even when this is replaced by a LED equivalent, the number of lumens remains the same at approximately 1,600lm.

When you go into the garage in the evening and turn on the lights, the amount of light seems appropriate and “bright.” But the next morning, when you open the garage door and turn on the lights, it feels as if the lights are barley working. In both cases, the lamps are putting out 1,600 lumens; however, in the daytime, you also have the contribution of the sun. But the lighting is still perceived as dimmer. Why is this?

It all comes down to this concept of perceived brightness. In the evening, the only light source that the brain has to observe and evaluate is the artificial lamps installed in each car bay. Assuming that the lamps are of sufficient lumens to illuminate the area, your brain will determine that the area is “bright.”

In the daytime, the brain is evaluating two light sources: the sun as well as the artificial lights. In this case, the sun is a much-brighter source and, depending on time of day, season, and weather, can be between 32,000-100,000 lumens. The brain must reconcile the difference between the 1,600lm artificial lamp, and the sun that is 20-62 times brighter. When it sees a lighting difference this large, it “determines” that the interior artificial light is dim and therefore your perceived brightness is low – even though the illuminance is greater due to the contribution of the sun.

This starts to illustrate the complexity of design for lighting designers. There are many factors that they must incorporate into the selection of a lighting system, not just how many lumens a modeling program says that it will be.

Questions about lighting design? Check out JDB Illumination and reach out to Craig G. Malesic, LC, EIT, PMP to discuss your questions or challenges via email or direct dial at 717.434.1558.

Connect with Craig

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What is the Ideal Color Temperature for Your Lighting?

Color Temperature in Lighting
By Craig Malesic, LC, PMP, EIT

In a prior post, Understanding Correlated Color Temperature (CCT), I shared insight about the quality of light color, from yellow to blue to “white hot.”

In this post, we’ll continue exploring color temperature for lighting, and how lighting design professionals determine what makes the most sense for a given space. There’s a lot more that goes into lighting design than picking a fixture that looks good!

Color temperature is often based on generally-accepted practices for type and use of a space. For example, here’s a general list of “typical” color temperatures for various spaces:

  • Residential: 2,700K-3,000K
  • Hospitality: 2,700K-3,500K
  • Office: 3,500K
  • Schools: 3,500K
  • Surgical Lights: 4,000K
  • Manufacturing: 4,000K-6,000K
  • Jewelry Cases: 6,000K

Some of this is also dictated by owner preference, manufacture recommendations, and standards from associated organizations. Ultimately, it is up to the lighting professional to use their judgement to decide when to step outside of these norms and do something different to better serve the space.

For example, I was recently commissioned to design lighting for a Catholic Church renovation in Harrisburg, Pennsylvania. I specified the lighting as 3,500K color temperature, and was questioned by the manufacturer on my choice. After all, the “typical” specification for a space like this would be for 3,000K lighting. So why the higher color temperature – don’t we want a warm inviting space, not office lighting?

Here were the variables evaluated during the design process.

Age of Congregants
The median age of the parish members was established through conversations with church staff and personal observations (we did not conduct a formal statistical analysis). It was determined that the median age was approximately 50 years old.

As we get older, normal aging occurs in our eyes (as well as the rest of our body). Part of the aging process entails the yellowing of crystalline structure in the lens of the eye (see diagram). This yellowing creates the effect of wearing yellow-tinted sunglass (of varying intensities). The aging process is gradual, so a person does not realize the change over time, just the slow degradation of sight.

Eye Diagram

By OpenStax College – Anatomy & Physiology, Connexions Web site. http://cnx.org/content/col11496/1.6/, Jun 19, 2013., CC BY 3.0, https://commons.wikimedia.org/w/index.php?curid=30148000

The yellow lens, also known as a luminous veil, is created because the changes in the lens structure start to absorb more blue light, making things appear yellow. This means that less blue light is transmitted through the eye.

To compensate for this situation, we decided to increase the amount of blue light. By increasing the color temperature from 3000K to 3500K, we were able to strike a balance between the older and younger congregants.

Natural and Artificial Light Competition
This church is unique in the amount and color of the stained glass. The church walls form an octagon, with seven of the eight walls covered in stained glass. Six of the walls are approximately 65% stained glass, and the seventh wall, in the front of the building, is 90% covered. The stained glass is designed with a field of blue glass as the background, and various additional colors forming the image for that panel.

Church Lighting 1

This layout presented a challenge in that the natural light, which is already a high color temperature, continues to present itself as predominantly blue. In the first photo of the space, you can see the lower color temperature lighting that contrasted with the blueness of the stained glass. The client desired to create a better balance between the artificial lighting and the natural lighting. This was both in the quantity of illumination as well as the perceived look (color temperature).

Church Lighting 2

A higher temperature was chosen to balance this look. As you can see in the second picture, there is a better balance in color. It was also accomplished by increasing the total illumination and providing more light to the ceiling.

Modern vs. Traditional Architecture
The church was designed in the 1970s and incorporated a modern architectural style, eschewing the traditional rectangular layout, incorporating parged concrete structures, and using stained glass as a primary feature.

This look and feel lends itself to higher color temperatures. The whites and greys of the updated design work well with light that has a higher blue component. The whiter light also provides for an enhanced, uplifting experience.

In summary, something as simple as color temperature can have a major effect on the look and feel of a space. Even though there are general rules of thumb for selection, these are only a starting point. An experienced lighting designer will need to decide if this “rule” makes sense for the space – or if the rule should be broken. Understating the interior design elements, such of paint, finishes, and millwork – along with the use or function of the space – all factor into making the best lighting decisions for the architecture as well as for the end-users.

Questions about the quality and color of your lighting? Need help with a relighting project? Learn more about JDB Illumination or contact Craig G. Malesic, LC, PMP, EIT at 717-434-1558 or email him.

Connect with Craig

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Holiday Lighting: How to be Safe & Creative this Season

By Craig G. Malesic, LC, PMP, EIT

Holiday Lighting
Christmas is my favorite time of year. And it’s not just for the obvious reasons of religion, family, presents, and the occasional hot toddy, either. When I gaze upon the holiday spirit with my lighting-designer hat firmly affixed upon my head, the only emotion that can describe my feeling is pure delight. Imagine, an entire season dedicated to folks doing their best to follow in your professions footsteps! If you haven’t figured it out yet, I’m talking about Christmas lights.

I enjoy seeing all the various displays put together. When driving, I even go to the extent of choosing varying and unique routes to maximize my Christmas light viewing! This often leads to some truly spectacular homes that do not disappoint. When sharing this passion with others, they often provide leads of Christmas lighting displays that I ‘need’ to go see. Currently on this list is a home atop a local mountain that supposedly has more than 100 illuminated deer in the woods. And this doesn’t even include the travel to regional Christmas lighting displays that my family takes to get into the holiday spirit.

So, because my “Love of Lights” extends to all forms, I thought that I would share some hints, techniques, and a little history about the wonderful world of Christmas lighting.

Holiday Decorations Factoid 1

Christmas Lighting Safety

Safety first…or if you are a fan of Mike Rowe (the former host of Dirty Jobs), Safety Third (if you don’t know what I am talking about, check out this short video). Here are a few safety tips that will aid in keeping you and your family – and home! – safe during the holiday season:

  1. Inspect your Christmas lights thoroughly before installation. Specifically look for frayed wires, broken lamps, bent electrical prongs, or any physical damage to the string of lights. If the wiring seems brittle and is flaking apart, it is time to replace the string.
  2. Consider using LED lamps and replacing your incandescent lighting. LED lights use much less energy, although they provide a different quality of light compared with traditional incandescent lights. This helps not only on the cost of lighting installation, but also on the amount of current going through the wiring. Wiring is sized to carry a certain amount of energy, measured in current. Use too much and the wiring can heat up and ultimately fail, in the worst case causing a fire. This is known as an overloaded circuit. With incandescent lights, you are limited to 2-4 strings connected together, depending on the quantity of lights, before you have too much current. LED lights can have as many as 22 strings before you approach the limit. Refer to the manufacturer’s instructions on your packaging for the actual maximum. (You kept the packaging, right?)
  3. Avoid creating tripping hazards. And no, this isn’t about tripping your circuit breaker. Getting power to where you need it often involves extension cords. Think about where and how you place cords. Sometimes we need to run across a walkway or other location that will create a potential tripping hazard. Can you run it a different route? Is there a different power source? Falls are the number one cause of unintentional home injuries, contributing to 662,000 annual hospital visits, according to 2010 data.
  4. Use ladders safely. You will potentially be using ladders to install your lighting. If you are going on a roof, use an extension ladder that extends at least 3’ above the roof lines. Have someone hold the ladder or properly secure it so that it does not tip or slide out from under you. Also make sure that you have the ladder installed on the correct angle. When using A-frame ladders, be sure that they are balanced on all four legs. Don’t overreach or stand above the manufacturer’s posted highest step.
  5. If it seems unsafe, it IS unsafe. Use your head. As great as Christmas lights are, you will not be able to enjoy the fruits of your labor from a hospital bed.

Holiday Decorations Factoid 2

Design Tips

We all “get by with a little help from our friends” when doing something outside of our normal wheelhouse. Here are a few ideas to make things even more stunning than you originally planned:

  1. Make your Christmas tree sparkle like the stars by adding dimension and layers. Many people just wrap the lights in a conical pattern around the outside. This creates a very flat and two-dimensional look. Here is what I do: first, choose a base color (I like to use blue) and wrap the trunk of the tree. This adds lights ‘inside’ the tree canopy. Then choose a complementary color (I like to use traditional white with a little blue thrown in). Weave the lights in and out of the branches in a ‘snake’ pattern. This will fill the volume of the tree with lights and add dimension. Think about the night sky, how it twinkles with stars that are both near and far, large and small. We are trying to add this same texture by using the three-dimensional space.
  2. Choose a color theme. Are you going all white? White with solid accent colors? Colored lights all the way? Whatever appeals to you is best. Just keep it consistent. Do not decorate the left of the house in white and the right with colors. Mix and match in a relevant pattern. Lay out the lights you have and figure out which design makes the most sense.
  3. Don’t overdo it with the projection lights. Projection lighting is great and serves a purpose, but just throwing one of them in the front yard really does not show a lot of effort. Weave this equipment into the overall design. I recently moved into a new house, and decorated four days after moving in. However, I’ve realized that the right side of my house still needs some type of illumination. I have the choice to use a 25’ extension ladder to place lights at the eves or to use a projection light. The rest of the house is decorated with traditional lights, so I will use a projector to add balance to the overall design.
  4. Don’t be afraid to do a Griswold Christmas! Lighting can be elegant, eclectic, or over-the-top. Being over-the-top takes time and dedication, but will delight folks from near and far…well, maybe not your neighbors, so be sure to take them a nice bourbon or bottle of wine and they may not mind too much. The bottom line is, be you.

Holiday Decorations Factoid 3

Christmas is a wonderful time of year. Religion, family, food, presents, and a general sense of joy. Christmas lighting cuts through the darkness of winter to bring joy to even the biggest scrooges of our day. Take the time to enjoy all the efforts of amateur lighting designers across the world. Take your family through neighborhoods and paths less-traveled. Share the joy of the spectacle and the elegance, and think about how YOU will make your display BIGGER and BETTER next year.

Craig Malesic is a Lighting Designer with JDB Illumination. He has designed Christmas lighting professionally. If you are a business or institution looking to make a splash during the holiday season, email or call Craig at 717.434.1558 and he will be happy to help illuminate your holiday! Just realize that corporate Christmas lighting design happens in August, not December!

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