The Dark Skies Matter

By James R. Benya, PE, FIES, FIALD

Designers of outdoor lighting are either facing or will soon face limitations on their designs by a new generation of codes and standards associated with the Dark Sky movement. While outdoor lighting codes are not a totally new idea, 21st century standards such as the Model Lighting Ordinance (MLO) are designed to restrict design freedom relative to off-site impacts like light trespass and light emitted upward into the sky. And the message is getting out to regulators. Those who work in California face the state’s environmental code, CalGREEN, and the Title 24 energy code that together limit commercial lighting very much like the MLO does, and the California Coastal Commission is especially concerned about any lighting along or near the coastline. Those who work in Florida know that lighting on or near many of its beaches is restricted to long wavelength, fully shielded luminaires, and not many of them. And those who work in Southern Arizona face stiff standards to help preserve the night sky for astronomy. Slowly, place by place, modern lighting codes are becoming part of our regulatory framework.

To any lighting designer, this might seem unfair and severely limiting to artistic freedom. Several generations of inspired and award-winning designs might not ever be replicated, and in a number of cases, the original is being constrained to limited use or removed altogether. For example, the spectacular 2020 lighting of the Acropolis, winner of three [d]arc Awards, employs flood lighting techniques and high color temperature light sources that are frowned upon among dark sky advocates. The spectacular and iconic Twin Towers of Light in New York are limited to sporadic use because they cause migratory birds to get lost in the beams and fly in circles to their deaths, by the thousands. And, in major cities where upper-story penthouse living is a luxury, prominent LED building identification and product advertising signs are facing well-financed opponents in high stakes legal battles to either prevent the signs altogether or, at least, require significant dimming and late-night shut off.

The start of the Dark Skies movement can be traced to the predecessors and founders of the International Dark-Sky Association. IDA was founded in 1991 by Dr. David Crawford, an astronomer and recipient of the 2021 IES Medal, and Dr. Tim Hunter. Although heavily influenced by the impacts on astronomy by anthropogenic light at night (ALAN), IDA has somehow managed to take a broad view of the topic and early on, looked upon ALAN’s impacts on people, plants, and all other manner of living beings. Even before the “human centric lighting” era, IDA members and other scientists were studying the impacts (mostly negative) of ALAN with disturbing results. Thanks to Dr. Crawford and his unbeatable promoting skills, the IDA and IES collaborated in developing the MLO, including the lighting zones, TM-15-11 and the BUG system. Meanwhile, a pair of scientists from the University of Southern California, Dr. Travis Longcore and Catherine Rich, published "Ecological Consequences of Artificial Night Lighting" that discusses the impacts of light at night on a number of different species. Their work became an integral part of the Dark Skies movement. There are still challenges in bringing them together, but that’s what I think professional lighting designers should do.

It has taken a decade since the MLO for the dark skies idea to even begin to mature. At first, there was an undercurrent of push-back because outdoor lighting was competing with the energy efficiency improvements of using LED luminaires. Early LEDs were most efficient at high color temperatures, and this gave rise to 4000K and 5000K lighting outdoors that still persists. But major improvements in 3000K, 2700K and now 2200K have occurred, and the efficacy of these sources is at least 75% of that attainable with the glaringly bright high CCT lights. This became critically important in 2015 when the American Medical Association, frustrated with a lack of progress and the amount of disinformation, took a stand in declaring all outdoor lighting should be 3000K and less. I remain frustrated, however, as far too many people confuse glare with good vision and think 4000K (or higher) is good because its glaring. It is not, with a few notable exceptions. For instance, the US Tennis Association (USTA) requires 4000K or higher for competitive tennis court lighting. I still wonder how they played tennis under incandescent lighting, but honestly, I think it has more to do with television cameras than tennis.

Softball complex lighting in Panama City Beach, FL

Photo Credit: Pete Strasser

That said, I am encouraged by the increasing stream of publicity and several important initiatives. In 2021, the IES and IDA announced a strategic collaboration to address “the global issue of light pollution that negatively affects our environment and the human condition.” The first joint action was to create “Five Principles for Responsible Outdoor Lighting,” that include:

1. All lighting should have a clear purpose.

2. Light should be directed only where needed.

3. Light should be no brighter than necessary.

4. Light should be on only when it is useful.

5. Use warmer colored lights where possible.

The MLO helped by providing professionals with guidance, and the USGBC helped by adding controlling light pollution as a point in LEED. But still, the three major decision makers for most lighting remain price, availability, and whether it will light the heck out of everything. Nasty, glaring 5000K LED floodlights and LED replacement lamps are leaping off the shelves of distributors and DIY stores and onto small commercial properties and private homes at an alarming rate, and ill-advised cities are installing 4000K LED streetlights. People tend to relate glare with safety and security. This awful trend breaks every one of the five principles, and it is out of control at the moment.

PUCL post-top LED lanterns from Holophane® at the City Hall in Fountain, Colorado.

Now along comes help from two influential organizations that I think can make a quantum difference. DesignLights Consortium® (DLC) has introduced LUNA, technical requirements that are “…intended to mitigate negative impacts of lighting at night by establishing system performance specifications and best practices.” It serves as a qualified products program similar to their energy efficiency programs, and I hope will be used by utilities and ESCOs to eliminate poor lighting practices in the retrofit and replacement lighting market.

The other is the National Association of Innovative Lighting Distributors (NAILD), a national nonprofit trade association driving lighting innovation through networking and education. They believe that through proper training, the distributor’s employee “at the counter” will educate electricians and contractors as they sell them appropriate gear. They have embarked on a Dark Sky Training program for their members. I think this may be one of the best ideas yet, as a huge percentage of lighting “designs” are in fact the recommendations of a salesperson. Try to imagine a world without unshielded 5000K floodlights and wallpacks! Now if only the DIY stores and websites would stop selling high CCT LED products to consumers.

Finally, dark sky concerns are not limited to lighting, either. A whole new generation of billboards and signs using LED pixels instead of floodlights is rapidly replacing old fashioned billboards, offering constantly changing and very bright images. In response, IES RP-39-19 dramatically reduces recommended sign luminance according to lighting zone, which is a start. But, it does not address the ability to “aim” the light of a modern LED billboard at an intended audience while not lighting neighbors’ homes and yards and seems based on obsolete technology and techniques. Now that LED billboards can be aimed and dimmed and their emitted spectrum controlled according to time, I foresee a revolution in this already evolving marketplace that will also require visionary leadership to develop appropriate standards based on new capabilities.

The big question that the lighting industry should ask itself is whether we want to make a bigger commitment and get better organized to address how our work ends up regulated. Like many things in our industry, we rely too much on personal initiatives until the government gets involved. That’s how energy codes went, and how, until recently, we, the IES, and the lighting industry developed the lighting energy codes as professionals and experts. Unfortunately, once governments get involved, the industry as a whole loses control as lobbyists and influencers take over and the probability of a high-quality and appropriate outcome diminishes. We are at an inflection point in the challenge to achieve and maintain dark skies. I hope we can rise to the occasion and, like we did with energy codes, encourage better applications, design skills and our own standards well enough to achieve significantly darker skies without excessive government blundering. ■