The Lightfair International (LFI) conference program featured a broad set of classes and sessions, and several addressed outdoor lighting in general, whether the light source was LED-based solid-state lighting (SSL) or legacy lamps. Sessions on best practices and the new Model Lighting Ordinance (MLO) stood out, providing key information on glare, the human visual system, and lighting levels that balance visibility and minimal light pollution.
In the outdoor-lighting area, Ray Grenald and Mark Harris of lighting firm Grenald Waldron Associates presented “Street and area lighting around the world – reducing energy, carbon emissions and light pollution while maintaining quality of life.” The session proceeded informally but provided a series of lessons that could easily be the basis of a best-practices guide.
Inconsistent global regulations
Harris lamented the lack of consistency in lighting regulations around the world. He said that Ottawa, Canada city code prescribes brightness levels that are 50% of Illuminating Engineering Society (IES) recommendations whereas the nation of Qatar in the Middle East prescribes double the IES recommendation.
The pair are generally in favor of less light at night, and suggested that too much light can reduce safety. Grenald said, “You can inadvertently put more light on the pupil causing it to close and you get less light in the back of the eye.” In such cases visibility is reduced, and glare is often the issue.
Harris said, “The key for me is more fixtures and greater control.” But of course more fixtures would drive costs up. Still there are other ways to improve lighting with the knowledge of the human visual system. Harris said, “We see brightness not foot candles and we see more vertical brightness than horizontal brightness.” Again glare from high angles is a major concern.
Grenald also addressed the need for security lighting in applications such as college campuses. He said, “Don’t make it brighter like most people do, but light the bushes and trees at a low level.” His point was to light places where a predator might hide.
Model Lighting Ordinance
Nancy Clanton of lighting firm Clanton & Associates also addressed outdoor lighting and specifically the MLO that the IES and the International Dark-Sky Association (IDA) have jointly developed. Some have seen the IES and IDA as having dueling goals, but Clanton said, “There really was a cohesive common goal.” Clanton said the organizations were seeking to minimize excessive light to save energy, improve the enjoyment of the night sky, and minimize the impact on bio-cycles of people and animals.
|MLO sample table|
At LFI Clanton said the MLO release was imminent and it has in fact been released to the public as of June 14. The goal was an ordinance focused on lighting first rather than energy. It is meant to apply to lighting applications such as monuments, signs, water features, and seasonal, landscape, emergency, and temporary lighting. Generally the target is lighting on private property. The MLO exempts street lighting although it can be adopted by small communities that lack the engineering resources to create their own street light regulations.
The MLO is defined by a series of five zones that are designated LZ0 through LZ4. Clanton said LZ4 is for places like Las Vegas or Times Square and “is not recommended for most cities.” LZ0, conversely, prescribes no constant ambient lighting and the use of motion sensors. Ultimately the success of the MLO will depend on city planners that make the right decision in choosing the appropriate zones and enforcing the MLO. The easiest way to learn more is to visit the IDA web site. Clanton said that Plymouth, MN and Anchorage, AK would be the first cities to adopt the MLO.