With LEDs, Knowledge is Power

I’ve been hired to review an architect’s lighting design and then design an appropriate control system. The fixtures selected are all LED products by a manufacturer that falls into the high-end residential/economy commercial range of quality and price. The cut sheets are extremely frustrating. After nearly a decade of LED lighting, and with all of the progress the industry has made in setting standards so that designers and specifiers know what they’re getting, this manufacturer still tells us nothing. What basic information is missing?

Lamp life. The only information even remotely connected to lamp life is the statement that the fixture is covered under a five-year warranty. There’s nothing else. Not a word. How much light, compared to initial output, can we expect at that five-year mark? We have no idea.

LEDs do not fail like other lamps do. They gradually dim as they age. At what point is the light output so low that we’d say the lamp is no longer useful? Right now the answer is when the light output has fallen to 70% of the initial output (often referred to as L70), although many designers prefer to use 80% of initial output (referred to as L80). This is calculated using a procedure developed by the IES and designated as LM-80 (details are here and here). What we want, at a minimum, is the IES LM-80 calculation of lamp life to 70% of initial output. L80 data would be even better.

Warranty. The warranty is not on the manufacturer’s web site so, although we’re told that it is good for five years, we have no information about what is covered and what is excluded.

LED manufacturer. With all other lamp types the designer chooses the exact lamp for the project. Criteria such as initial lumen output, mean lumen output, lamp life, color temperature, CRI, and the manufacturer’s reputation for quality are all valid considerations. We have standards that allow designers to make valid comparisons between LED products, too, but we can do that only if that information is generated and shared. I suspect that this fixture manufacturer uses LEDs from a several manufacturers based on the best price available, and that the performance of those LEDs varies widely.

Color consistency. The cut sheet says that the standard applied to their LED selection is, “minimum 3-step color binning.” We are left to infer that means three-step MacAdam Ellipses. A one-step MacAdam Ellipse describes a region on a chromaticity diagram or color space where the edges of the ellipse represent a just noticeable difference from the color at the center (additional information on MacAdam Ellipses is here and here). The data is usually plotted on the CIE 1931 (x, y) chromaticity diagram. The diagram below shows 10-step MacAdam Ellipses.

"CIExy1931 MacAdam". Licensed under CC BY-SA 3.0 via Wikimedia Commons - http://commons.wikimedia.org/wiki/File:CIExy1931_MacAdam.png#/media/File:CIExy1931_MacAdam.png — “CIExy1931 MacAdam”. Licensed under CC BY-SA 3.0 via Wikimedia Commons – http://commons.wikimedia.org/wiki/File:CIExy1931_MacAdam.png#/media/File:CIExy1931_MacAdam.png

The color variation within a three-step ellipse would be noticeable to over 99% of the population. Worse, though, is that a three-step ellipse is the minimum, not the maximum. Knowing this, the designer should have no expectation of color consistency from one fixture to another.

Photometrics. The cut sheet contains no information about the optical performance of the fixture. IES files are available, but it’s very difficult to look at the array of numbers and understand performance, which is why the good manufacturers include photometric information on their documentation, including candlepower distribution curves and CU tables.

Part of my review will be pointing out the lack of data about the specified fixtures and recommending several alternates by manufacturers who provide the information necessary to evaluate their products.

IALD Set To Launch CLD Credential

After five years of planning the IALD is set to begin accepting applications for the newly created Certified Lighting Designer (CLD) credential. The CLD credential is similar to the LC (Lighting Certified) credential in that it is meant to demonstrate lighting design competency. Unlike the LC, the CLD credential will be awarded based on a portfolio review that demonstrates proficiency in seven areas of professional practice rather than by passing a written test. The other difference between CLD and LC is that the CLD will only be awarded individuals with at least three years of experience as a lead designer. This means that some people who have earned an LC (sales reps, for example) will not be eligible for the CLD.

Why does this matter? First, the LC credential carries some weight, mainly because since 2009 the GSA has required the lead lighting designer on U.S. government projects to be Lighting Certified. However, many designers are unhappy that people who aren’t practicing lighting designers can hold an LC credential. By limiting the CLD to working designers, the IALD hopes it will be seen as attesting to the holder’s skills as a lighting designer, not just their knowledge about lighting in general.

Second, lighting design is in some ways the redheaded stepchild of the architectural design professions. Lighting design is not licensed, meaning that anyone can say they’re a lighting designer. As a result, lighting design is provided by electrical engineers, architects, interior designers, sales people, and manufacturers who have widely varying education and training, and with widely varying degrees of success. The CLD could be a means of identifying who is a lighting designer and who is not.

The key to the success of this project is public awareness. If the IALD only talks about CLD to the lighting design community it will be nothing more than letters following a person’s name on their business card. Building owners and other clients have to understand the value that professional lighting designers can bring to a project, and have to insist that the design team includes a professional lighting designer. Architects and interior designers have to understand the role of a lighting designer and be willing to tell their clients that a professional lighting designer is an important part of the design team who is worth the additional fee. If, through the CLD, the IALD is able to raise awareness about lighting design in those who can benefit from it, it will have been well worth the effort.

OLEDs Are Ready For Their Closeup

Last week I attended a webinar on the history, future, and application of OLEDs presented by Dietmar Thomas of Philips. It was an interesting and informative hour that has just been posted online. Perhaps the most surprising thing is that Philips sees commercial lighting fixtures lamped almost exclusively with LEDs and OLEDs as soon as 2020! The webinar is worth the time. Take a look.

Starting A New Design

I’m between classes at Pratt, so I’ll have to be brief. It’s the time in the semester when my students start to feel overwhelmed. After talking about vision, light, psychology, design, lamps, color, and light fixtures they’re about to start working on designing projects for class. The most common question is something like, “How can I possibly organize all of this information and start to make meaningful design decisions? I need to pick a light fixture, then I need to pick a lamp for that fixture, then I need to lay out the fixtures to arrive at the lighting that I want, right?”

Wrong! A lighting design doesn’t come from the lighting fixture, so design decisions shouldn’t start there. In a push-me-pull-you kind of way the first questions are always about the end result. Rather than choose a fixture and follow the light down into the room, what we need to do is understand the lighting requirements and follow the light up to the lamp and luminaire. How do you want the space to look and feel? What lighting techniques can help achieve that look? Is there an overarching thematic element that needs to be included? How can we express the lighting goals in terms like intensity, color, and distribution? The answers to those questions should start to lead the designer to requirements for the fixture/lamp combination, and to the number of fixture types required to implement the design.

I explain that it’s not always a linear process, and that a certain amount of trial and error is part of any design. “Does this fixture give me the distribution and intensity I need?” isn’t always a yes/no question that can be answered by looking at a cut sheet. Sections may have to be studied, calculations run, different lamps and accessories considered, always with the end goal in mind.

Yes it’s hard. So hard, in fact, that some people spend several years studying light and design at the college level before getting their first job, only to discover that there’s so much more to learn! If you have a passion for light and design, though, trust me it’s worth it.

Best and Worst Lighting at the Grammy’s

Yes, the Grammy Awards are all about the music, but for lighting designers it’s also about the way the performance are lit. Last night showcased some of the best and worst lighting you’re likely to see on tv this year. Among the best was the lighting for Ariana Grande’s performance of “Just A Little Bit Of Your Heart.” Surrounded by glowing crystals, luminous fog, and a small backlit orchestra all she had to do was stand still and sing. The lighting director created a beautiful environment of soft light and slowly changing color that was in harmony with the feeling of the music.

https://www.youtube.com/watch?v=t1Tvd_ry024

Among the worst lighting was Kanye’s performance of “Only One.” The song opened with him standing over a beam of light shooting up from the floor. As he sang he moved in and out of the light, but without meaning or intention. He was visible at some times and not at others, always with shadows obscuring his face. At the beginning of the second verse the music swelled, providing an ideal opportunity to build the light so that he was better lit, but nothing happened. It’s impossible to know why. Did he tell the lighting director not to change the lighting? Did he skip rehearsal so that there wasn’t another lighting cue ready to go? Either way the result was him wandering around, in and out of the light, for the entire song. Here it is:

http://youtu.be/VwrtC_xl0V4

Digital Resources Now Available

So…Wiley has had some trouble with this book’s section of their web site. To make things easier for students I’ve added a Resources section to this site with PDFs of flashcards, brief self-evaluation tests, and a few calculators. Just click on the Resources tab above. The only things missing are the animations that are reference in the book. Unfortunately, I can’t find a way for WordPress to host interactive components, but everything else is just a click away. You’re welcome!

DOE Extends Comment Period for General Service Lamps Standards

The Department of Energy (DOE) has extended the comment period for proposed energy efficiency standards for general service lamps (GSLs) until February 23, 2015. Documents associated with this set of standards are Docket No. EERE-2013-BT-STD-0051. There is a link on that page to submit comments.

You may recall that the Energy Independence and Security Act of 2007 (EISA) set minimum efficiency standards for medium screw base (a.k.a. E26) general service lamps (a summary of requirements and exemptions is here). Those minimum standards were phased in by wattage and now cover GSLs from 40 to 100W. Decorative and other specialty lamps are excluded. A public meeting and webcast was held on January 20^th to explain the new standards for consumer lamps. You can download a PDF of the presentation here. It’s a long presentation of 94 slides, so here’s a summary.

1. The DOE is considering establishing standards for the following lamp types:

Integrated, non-reflector, medium screw base lamps with a lumen output between 310 and 2,600 lumens
GU24 base, non-reflector lamps with a lumen output between 310 and 2,600 lumens
Non-integrated, non-reflector, pin base, CFLs with a lumen output between 310 and 2,600 lumens

2. The DOE is considering requiring the following lamps, which are currently exempted from EISA requirements, to comply with the new standards:

Left-handed thread
Marine
Reflector
Rough service
Shatter-resistant
3-way
Vibration service
Specific lamp shapes

3. The DOE is also considering not setting standards for certain lamp types for reasons that include:

Low potential for energy savings
Technological infeasibility
Restrictions from the Appropriations Rider

There are over three dozen identified issues that are open for comment. These standards will have a far reaching effect, so I urge you to look over the presentation and submit comments.

Start of the Semester Fun

The spring semester starts this week for my Pratt students and next week for my Parsons students. The beginning of the semester is always a little hectic and stressful. Here’s a bit of fun to take the edge off. Not many forms of energy have their own song. Here’s “Electricity” by Orchestral Manoeuvres In The Dark (aka OMD). It’s so painfully dated that it’s funny.

2014 Hottest Year On Record

By now you have, no doubt, seen the headline that 2014 is the warmest year since reliable record keeping began in 1880. This was jointly announced by two US agencies – NASA and NOAA – and corresponds with an announcement by a similar agency in Japan. I’m not going to retell that story here, but I do want to repeat some of the most alarming points.

The 10 warmest years in more than a century have all occurred since 1997. That’s new high temperature record in 10 of the past 14 years.
Average temperatures in the US have now exceeded the 20^th century average for 38 consecutive years. That’s every year since 1976. Think about it. No one born after 1976 has known a year colder than average.
The last time the global temperatures fell below the 20^th century average for a given month was in 1985.
The last full year of colder than average temperatures was 1976.
The last record cold year was 1911. That’s 103 years ago. Now go back and look at the first bullet point.

Here’s a graph illustrating the trend.

For those who think that climate change is a liberal conspiracy, my suggestion is to take it up with the Pentagon. In 2012 the Pentagon formed a climate change working group. The result of their work is the DOD 2014 Climate Change Adaptation Roadmap, which was released in October 2014 and accepts climate change as a fact. About the report, Defense Secretary Chuck Hagel said that “Politics or ideology must not get in the way of sound planning.”

Light & Health Seminar

The New York City chapter of the IES will host a presentation by Mariana Figueiro and Leora Radetsky of the Lighting Research Center titled “Swimming in an Ocean of Light: Using Light for Health and Well-being.” The program will include the IES Light and Health seminar, which they co-authored, as well as updated material with recent research results and their insights about “turning research into design practice.”

If you’re interested you can RSVP here.