Promoting Lighting Design

By some estimates less then 10 percent of construction and renovation projects include a professional lighting designer on the design team. Why? Who’s looking after the lighting design? What can the lighting design community do about it?

The reasons projects go forward without a lighting designer range from the owner’s lack of understanding of what a lighting designer does to the architect’s desire to keep fees low. These are usually coupled with the belief that other team members can take care of the lighting just as well as well as a lighting designer. The “others” who may provide some or all of the lighting design include the architect, interior designer, electrical engineer, electrical contractor, and lighting salesperson. These other professions can act as lighting designers because the practice of lighting is so young and is unlicensed.

Why should architects and building owners hire a lighting designer? My first answer is, “You’re hiring experts in every other aspect of building design and construction, so why would you NOT hire an expert in lighting, too? Don’t you want the building to look as good as you imagine it will?” My other answers are:

Research has shown that the benefits of high quality lighting design include increased sales, worker performance, and student test scores.
Professional lighting designers develop unique designs specifically for each project. They know more about light and lighting, put more time and effort into designing the lighting, and will produce better results than any other team member.
The lighting industry is moving and changing faster today than at any time since the invention of the light bulb. Lighting designers invest an enormous amount of time and energy keeping up to date on new light sources, energy codes, control systems and the like. No other team member is as well informed about the current state of the field.

What can the lighting industry to do promote the use of lighting designers? It seems to me that our professional organizations, especially the IES and IALD, have to take the lead here because individuals can’t have enough impact. Both organizations do a lot of work within the industry, but I don’t see any outreach to the real decision makers. What could they do? Here are a two thoughts:

Provide articles to AIA and other professional publications promoting the benefits of working with lighting designers.
Present seminars and staff booths at conventions of AIA, SCUP, Retail Design Institute and others to promote lighting design.

What do you think? What can we do to promote lighting design?

DOE Updates Energy Conservation Requirements

On September 26, 2014 the U.S. Department of Energy issued a determination that ANSI/ASHRAE/IES Standard 90.1-2013 would achieve greater energy efficiency in buildings subject to the code than the 2010 version. The DOE analyses determined that the energy savings would be:

8.7% energy cost savings
8.5% source energy savings
7.6% site energy savings

As a result, all states are now required to certify that they have reviewed the provisions of their commercial building code regarding energy efficiency and, if necessary, updated their codes to meet or exceed the 2013 edition of Standard 90.1. States must submit certification of compliance by September 26, 2016 or explain why they cannot comply.

Why is this happening? The DOE is required by the Energy Conservation and Production Act (42 USC 6833) to review each new edition of ANSI/ASHRAE/IES Standard 90.1, and issue a determination as to whether the updated edition will improve energy efficiency in commercial buildings. If the determination is that the new version will improve energy efficiency, that standard becomes the new nationwide minimum requirement. States aren’t required to adopt Standard 90.1, but whatever standard they develop or adopt must be at least as stringent as Standard 90.1.

Some of the changes in the new standard are:

Lumen Power Densities (LPDs) for most building and space types are reduced by approximately 10% from the 2010 version.
More stringent requirements for lighting controls
A new table format for determining LPDs and control requirements in individual spaces

The DOE website contains additional information, including PDFs of the analyses they conducted.

Renewables: Responsible and Necessary

There are two interesting and related articles on the interwebs today. The first is an article at Climate Central and reprinted in Scientific American that summarizes a study published in Proceedings of the National Academy of Sciences. The study is titled Integrated Life-Cycle Assessment of Electricity Supply Scenarios Confirms Global Environmental Benefit of Low-Carbon Technologies. It looks at the life-cycle environmental and climate costs of a continuing shift to renewable energy through the year 2050. The researchers assumed that by then 39 percent of global electricity production will be generated by renewables and asked themselves what the environmental impact would be.

We all know that sources of renewable energy produce less CO2 during their operation than burning fossil fuels, but that’s not the whole picture. The life-cycle analysis looked at the environmental costs and benefits of renewables and traditional sources of power from their inception (such as mining the ores needed to produce the metal parts) through their entire operational lives. For example, wind turbines require more than 10 times the iron needed for comparable electricity generation powered by oil or coal, and solar panels require up to 40 times more copper. That’s a lot of additional mining, with the associated environmental impact. Are renewables really better for the environment?

The answer turns out to be, “Yes.” How could that be? There are two factors. One is that after a solar panel or a wind turbine is manufactured it doesn’t require additional raw materials. Coal, oil, and gas-fired power plants require a continuous input of new raw materials that are extracted, transported, and then burned. The second is that although renewable energy equipment requires more material to produce, the required amount is a small amount relative to global production. For instance, the copper required for the estimated increase in solar panels over the next 36 years is only 2 years of copper production (or 5 percent) at current rates.

An increase in environmentally friendly energy production is good news because the second article, published in the op-ed section of today’s New York Times, says that historical trends in increased lighting efficiency suggest that we may see an increase, not a decrease, in energy consumption in the years to come. The authors explain that as the production of light became cheaper, from coal gas to whale oil to kerosene to electricity, the demand for these cheaper technologies resulted in an overall increase in energy consumption, a process called rebound. They note that

The I.E.A. and I.P.C.C. estimate that the rebound could be over 50 percent globally. Recent estimates and case studies have suggested that in many energy-intensive sectors of developing economies, energy-saving technologies may backfire, meaning that increased energy consumption associated with lower energy costs because of higher efficiency may in fact result in higher energy consumption than there would have been without those technologies.

That’s not a bad thing. Most people in the world, still struggling to achieve modern living standards, need to consume more energy, not less. Cheap LED and other more efficient energy technologies will be overwhelmingly positive for people and economies all over the world.

But LED and other ultraefficient lighting technologies are unlikely to reduce global energy consumption or reduce carbon emissions. If we are to make a serious dent in carbon emissions, there is no escaping the need to shift to cleaner sources of energy.

Circadian Lighting

A recent article in The Wall Street Journal discussed the possibilities and benefits of lighting systems that shift color to mimic the changes in daylight. It’s a complicated subject so it’s not surprising that some of what’s reported is inaccurate, so let me clarify a few things.

First, our current understanding of how light affects our circadian rhythms is that a light activates a type of cell in the retina called intrinsically photosensitive retinal ganglion cells (ipRGC). These cells, unlike rods and cones, are unrelated to vision. The signal they send to the brain is received by the suprachiasmatic nucleus (SCN), which is the body’s hormone regulator. As the graph below illustrates, the ipRGCs are most sensitive to short wavelength (blue) light and, unlike rods and cones, are unaffected by long wavelength (red) light. (A more detailed explanation can be found in Chapter 16 of Designing With Light, and in this article from the Journal of Circadian Rhythms.)

ipRGC (black), rod (blue), and cone (red) sensitivity curves

The ipRGCs signal to the SCN, which keeps our circadian rhythms are kept in sync with the day/night cycle, seems to be affected by three factors: color balance; intensity; timing. Cool (bluish) light should be delivered at a relatively high brightness in the morning hours. Delivering cool light in the evening hours can disrupt sleep and other processes controlled by the SCN.

Next, there’s nothing special about LED lighting that makes it uniquely appropriate for this application. Fluorescent, HID, and incandescent light (adjusted with color filters) can all be used to create a system that delivers cool light in the morning and warm light in the evening. In all cases, this involves the use of light sources of several tints (warm, cool, and possibly neutral) that are individually controlled. The WSJ is completely wrong when it says “unlike incandescent or fluorescent lights, LED lights’ materials and electronic components allow for finer adjustments of color, brightness and intensity.” A single LED creates light of a single color. To shift colors a second LED is required. Brightness and intensity are the same thing. With LEDs set to surpass sales of all other light sources within the next several years, research involving sources other than LED is nearly non-existent. Naturally, researchers are using LEDs to test theories and to develop demonstrations and products.

Finally, it would be helpful if the WSJ had defined two terms – color temperature and CRI (Color Rendering Index). Both are explained in Chapter 8. Color rendering and CRI are briefly explained in this post. CRI and color temperature are both addressed in this post.

People’s Climate March

Today is the People’s Climate March here in New York City. Sponsored by peoplesclimate.org, the march here is joined by events in other major cities around the world, including London, Berlin, Bogota, Istanbul, Paris, Rio, Delhi, Melbourne, Johannesburg, Lagos, and Amsterdam. The marches and other events are intended to put pressure on international leaders who will meet at the United Nations Climate Summit 2014 on Tuesday to create the framework for a global agreement on emissions that (it is hoped) will be agreed upon in Paris late next year.

If that agreement occurs it will certainly be a case of politicians leading from behind. As I’ve noted here and here and here, researchers at organizations as diverse as NASA, NOAA, and IPCC have been telling us that the climate is changing now, that change is accelerating, and that we’ve already reached the tipping point in places like Antarctica’s Western Ice Sheet. And the news just keeps piling up. NOAA has announced that the combined average temperature across global land and ocean surfaces for August 2014 was a record high for the month, at 1.35°F above the 20th century average of 60.1°F, topping the previous record set in 1998. The global land surface temperature was 1.78°F above the 20^th century average. Here’s a map of the global temperature variations compared to the base period of 1981-2010.

The August report means that globally, June through August 2014 is the 5^th hottest on record. The four periods that were hotter than this year have all occurred since 1998.

Since the founding of the IPCC in 1988 progress has been slow and halting (a history of UN climate actions can be found here). Let’s hope that strong action is agreed to this time.

IES Releases RP-31-14 Recommended Practice for the Economic Analysis of Lighting

The Illuminating Engineering Society has released a new Recommended Practice. RP-31-14 Recommended Practice for the Economic Analysis of Lighting is now available as a PDF download or soft back from the IES Online Store. From the IES:

Good lighting should be responsive to the needs of the user. Among those needs are the aesthetic and the visual, as admitted in the oft-quoted “lighting is both a science and an art.” But the user also has economic needs. In fact, it is the economic needs that often drive the decision making process when lighting systems are designed and purchased.

This recommended practice is written from the point of view that “economic analysis” is not the same as “how to beat the budget.” Rather than considering economic analysis as the antithesis of engineering or artistic analysis, is should be thought of as subsuming these other needs. When a competent lighting professional takes care of economic needs, in conjunction with the artistic, engineering, and other needs, it increases the likelihood a project will have success and longevity. Financial considerations ad demonstrated through an accurate lighting financial analysis are important, but other elements such as aesthetics, human visual performance resulting from a lighting system appropriate to a given task, and other considerations involved in lighting for the human and natural environment are of equal importance.

Fixture Cost Frustration

One of my clients has expressed frustration with the caveats I place at the end of my lighting fixture budget. Why can’t I give the client a simple budget estimate? The answer is that fixture manufacturers don’t have a manufacturer’s suggested retail price (MSRP) for their products, which is something we’ve all come to expect for products ranging from potato chips to cars. We all know that things we want to buy have an MSRP or list price and it’s up to the seller to decide whether or not to sell at a lower price.

However, with lighting equipment the sales representative and the manufacturer collaborate to establish pricing for each project (see chapter 9). Larger projects with more luminaires will usually pay less per luminaire. This can be frustrating for everyone. It’s hard to develop a reliable fixture cost database when fixture costs are variable.

Another issue with pricing from the sales rep is that it is usually dealer net, distributor net, or DN pricing. This means that the luminaire price the sales rep gives to the designer is the price that the electrical distributor will pay the manufacturer. It does not include the electrical distributor’s markup for overhead and profit, nor does it include possible markups by the electrical contractor and/or the general contractor. It is up to the lighting designer to estimate the total markup(s) as well as taxes, shipping and such, and add that amount to the projected lighting fixture budget, but designers have no direct knowledge of what markup these firms will add, nor do we have any control over their markups. The result is that I wind up footnoting my budget with notes like markup percentages are estimated, pricing is based on cost estimates provided by sales representative, and pricing is based on projects of similar size and scope.

Finally, as I explained here, the fixtures that I specify may not be purchased for the project. Once substitutions enter the picture another layer of mystery is added. Yes, it’s complicated. Here’s a flow chart that tries to explain the flow of information (denoted by question marks) and money (denoted by dollar signs) of design and sales relationships. See chapter 9 for a full explanation.

Dimming That Doesn’t Dim Off

Recently a designer specified 0-10V dimming for a series of LED downlights. The electrician powered the LEDs by connecting them to a nearby breaker panel. The 0-10V control signal was generated by the lighting control system. This was a simple system that should have worked with no problems. Much to everyone’s surprise the lights would dim but they wouldn’t go off! What happened?

Dimming light sources other than incandescent is a technical challenge. It requires the ballast (for fluorescent, HID, cold cathode, etc.) or the driver (for LEDs) to precisely control the amperage and the voltage, and may also require converting the incoming AC to a DC output (for some LEDs). This is difficult for fluorescent and HID lamps because the electricity must arc from one side of the lamp to the other, and at low power levels that arc simply fails. Dimming LEDs often results in a visibly jittery dimming curve as well as a jump to zero when dimming down and a jump to on when dimming up. (This article in Electrical Construction & Maintenance is a good overview of the problems with dimming LEDs.)

In architectural lighting, however, the inability to dim all the way to zero is usually not seen as a problem. Typical dimming applications such as classrooms and meeting rooms may want to dim lights for a presentation, but some light is still desirable so that attendees can see each other for discussion and see their desktop to take notes. Dimming is acceptable as long as the dimming is smooth down to a minimum light level. In these installations the drop from, say, ten percent to zero isn’t an issue because it doesn’t happen until the room is empty and the lights are turned completely off.

With 0-10V dimming, though, the dimmer or driver is powered by the incoming line voltage, so its always operating. As a result, its minimum operating capacity is also the fully dimmed state. A 100-10% ballast or driver, for example, has a minimum output of 10% not zero. When the fader is at the bottom of its travel we would normally expect the lights to go off, but they only go to 10%. Here’s a graph showing the performance of representative LED fixtures dimmed with a 0-10V dimmer.

The solution is to provide separate switching of the line voltage delivered to the fixture. Most wallbox dimmers have a toggle switch below the fader so that the fixture can be shut off at any time. Here’s a schematic of a simple circuit.

Other solutions come from other dimming techniques, including three-wire and four-wire dimming where the line voltage and the control signal come out of the same device. This guarantees that at a minimum state power to the fixture is shut off. Other control protocols, notably DMX512, and the electronics that utilize them can usually dim to zero.

Light and Health

The DOE has recently published a fact sheet titled Lighting for Health: LEDs in the New Age of Illumination. It summarizes the Trends in Neuroscience January 2014 article Measuring and Using Light in the Melanopsin Age. Both publications explain the current understanding of our visual and nonvisual response to light.

The basics of our visual response to light is understood by everyone – it gives us the ability to see. The nonvisual response is less known generally, and is still being researched by scientists across the globe. This is discussed in my book in Chapter 16 Light and Health. What we have learned in the past two decades is that there is a third type of light sensitive cell in our eyes (the first two being rods and cones) called the intrinsically photosensitive retinal ganglion cell (ipRGC). When light strikes the ipRGC a pigment called melanopsin breaks down, sending a signal to the brain. That signal doesn’t go to the visual cortex, however, but to the suprachiasmatic nucleus (SCN) the body’s timekeeper. The SCN regulates circadian rhythms and the production of hormones affecting alertness, heart rate, blood pressure, stress response, and more. The SCN is reset by information from the ipRGCs. Simple exposure to light, though, is not enough. The exposure time of day, duration, and wavelengths all contribute to proper synchronization. SCN regulation seems to be maintained by high brightness, short wavelength light in the morning (i.e., morning daylight). If appropriate stimulation does not occur, the timing signals for hormone production can become desynchronized. It is known that circadian desynchronization plays a roll in insomnia, mood, depression, reaction time, creativity, and alertness. It is suspected that this desynchronization also plays a roll in cancer, diabetes, dementia, and cardiovascular disease.

This has lead to some talk of light as a drug that controls the SCN. At this point it is probably premature to attempt to apply this information in most lighting designs because most spaces have a wide range of users with a similarly wide range of needs. A lighting design for the overnight shift, for example, may not work well for the day shift. There are a few rules of thumb that can be applied in specific circumstances. For example, a designer can minimize the nonvisual circadian response by limiting the amount of light, especially short wavelength light, reaching the eye. However, the science is still in the early days and the specifics about the effect of light level, spectral distribution, and timing on users and for various applications are not clear.

New LED Performance Measurements

The Illuminating Engineering Society (IES) has published two new documents related to measuring the performance of Light Emitting Diodes (LEDs). The titles, as well as the aspects that are included and excluded, reveal the complexity of LEDs.

The basic problem is that LEDs typically do not fail the way other lamps do. Instead of a failure that results in the end of light output, LED output fades over time. The result is that at some point, although the LED is still producing light, it is no longer producing enough light for the application so we would say that it has reached the end of its useful life. LEDs have very long lives and relatively short development cycles so it is entirely possible that by the time testing of an LED is complete a newer product has already replaced it. This is compounded by the sensitivity LEDs have to temperature, voltage, and other factors that can mean lab measurements differ greatly from real world measurements. This gives rise to the need for clearly defined testing procedures that reproduce conditions found in typical installations so that designers can rely on the information from the manufacturers.

The first document is LM-84-14 IES Approved Method for Measuring Luminous Flux and Color Maintenance of LED Lamps, Light Engines, and Luminaires. (In the IES naming system LM stands for lumen maintenance, 84 is the document number, and 14 is the year it was issued or updated.) It describes the procedures to be followed in obtaining luminous flux (light output) and color maintenance measurements under standard operating conditions. However, it does not provide information on sampling, or extrapolation of the data for longer time frames.

The second document is LM-85-14 IES Approved Method for Electrical and Photometric Measurements of High Power LEDs, which describes the procedures to be followed in performing accurate measurements of light output of white and colored high-power LEDs. The procedures do not cover LED arrays or modules, AC driven LEDs, among other things.

These two documents join several others that describe the testing and measuring of LEDs. The first is LM-79-08 Approved Method: Photometric Measurements of Solid State Lighting Products, which describes the procedures for testing and reporting of: total flux (light output); color temperature; color rendering index, electrical power characteristics; efficacy (in lumens/watt). LM-79 requires testing of a complete lighting fixture. It does not apply to bare LED packages. LM-79 does not measure the distribution, only the total light output. As a result, it does not provide us with complete photometric performance of the fixture tested.

The next standard is LM-80-08 Approved Method: Measuring Lumen Maintenance of LED Light Sources, which is intended to measure only the LED package, not a complete fixture. LM-80 does not define the end of life for an LED package. It is simply method for determining the light output degradation. LM-80 outlines the testing conditions and the measurement methods that are to be used to measure, track and report the lumen maintenance of an LED package over the course of 6,000 hours. it does not provide a means of estimating life expectancy or light output beyond 6,000 hours.

TM-21-11 Projecting Long Term Lumen Maintenance of LED Light Sources picks up where LM-80 leaves off. (TM stands for Technical Memorandum) It recommends a method for projecting the lumen maintenance of LEDs using the data obtained from LM-80 testing. TM-21 is used to derive L70, which is the number of hours, or life, before the LED package is emitting 70% of the initial lumens. L70 is the number most frequently used by manufacturers as the life, or the useful life, of their LEDs.