The Illuminating Engineering Society (IES) unveiled a new lighting practice standard, titled Quality Lighting Design for People in Outdoor Environments. Recently, Nancy Clanton (Clanton & Associates) and Randy Burkett (Randy Burkett Lighting Design, Inc), members of the subcommittee that wrote the standard, presented the new lighting guidance, which centers on design elements of outdoor space and the context and hierarchy of lighting the nighttime environment. Rather than dealing with criteria, LP-2 presents the issues of outdoor lighting for pedestrians with a focus on design applications. Here is a recap of Clanton and Burkett’s introduction to LP-2-20.

LP-2 flips the traditional approach of lighting outdoor spaces by putting the pedestrian, not the vehicle, at the center of the design process. As the subcommittee began its work on LP-2, it needed to further define a pedestrian to include not only people, but their activities: biking, riding scooters and skateboards, rollerblading, walking, attending concerts, and so on.

Lighting design in the outdoors takes into consideration not only human activities, but also the context of pedestrian spaces, among them the architecture, changes based on day to night, and adjacencies. Is the space a large, open park or a series of streetscape parklets? Is it an active place? Transitions are important in outdoor areas, and changes in lighting is an important way to signal transitions from an area, an activity, or a task. Such context determines how a designer approaches lighting spaces for pedestrians.

Levels of the Hierarchy

The standard is based on a hierarchy of design elements to consider when lighting outdoor spaces for people. Randy Burkett notes that the levels of the hierarchy may change in importance depending on the environment that is being lit. Reassurance, for example, may become more important in areas that are unfamiliar or associated with something negative, where safety may be less important when lighting a gated community or familiar area.

1. Orientation and wayfinding help people understand a space. Orientation is an essential function of lighting and contributes to a pedestrian feeling comfortable in a space. A person’s efforts to navigate a space can be both conscious and subconscious. Lighting that achieves recognizable contrasts, patterns, and predictable visual cues all aid in a person’s ability to orientate.
2. Lighting that reassures is the result of objective design (meeting codes) and subjective design (meeting the needs of a person to not feel doubtful or afraid). Lighting that allows a person to recognize faces and expressions and is uniform are important to a person’s feeling reassured in an outdoor space. Coherence and understanding also contribute to a sense of reassurance.
3. Lighting design that reveals terrain, curbs, boundaries, and objects creates a safer, less hazardous experience for a pedestrian. Avoiding glare, overlighting, and shadows help to create a physically safer space.
4. Lighting designers can choreograph the environment, considering CCT and spectrum, architecture, texture and material, and function in designing lighting that creates atmosphere and enjoyment. Lighting for atmosphere and enjoyment differs for different environments. Luminance ratios and patterns, lighting levels and uniformity, and glare reduction are all aspects of a lighting design that elicits emotional responses and an improved perception of the space.

Randy Burkett sums up the importance of context and considering the whole environment and pedestrian experience with this example.

“I was working with a client on a lighting design for the city’s entire urban area. I took places and landmarks within the city that are well-known and identified during daytime hours. I then overlaid photos of those places and outlined the landmarks and elements within them. I was able to demonstrate to my client that less than 15 percent of what one sees is a street or sidewalk (the horizontal plane). Building facades, tree canopies, sculptures, play structures, furnishings, etc., make up a far larger percentage of what we see and take in and help orient and reassure us. So why have we spent so much time lighting streets and sidewalks and neglected the other 85 percent? Lighting designers need to be mindful of both near field and far field conditions. It’s the total environment that defines a person’s sense of place. The elements of the hierarchy remind us to assess the role all of these things play. It’s how we become mindful of an environment, not just what is in front of us. It’s the context of everything that is our field of view.”

Determining Site-Specific Light Trespass Levels

“Not many municipalities have lighting ordinances, but they do have land use zones,” she says. Lighting Zones are rated from LZ0 to LZ3, depending on residential and commercial density or the Land Use Zone. First, find out what land use zone the site is in. Once you know the site’s land use zone, assign the lighting zone at the same level as land use. For example, an LZ0 lighting zone might be a nature preserve; a lighting zone of LZ0 would put very little light over its property lines. A lighting zone of LZ1 for a rural residential land use puts a little more trespass across properties.

Finally, says Clanton, think back to the BUG ratings of 0, 1, 2, and 3. “An LZ0 lighting zone should be assigned fixtures with BUG ratings of B0, G0, and U0; an LZ1 lighting zone would have maximum BUG ratings to match. The two align, and it really works quite well in determining maximum trespass levels.”

Clanton sees an opportunity for landscape architects and lighting designers to help educate land use planners who aren’t always knowledgeable about lighting zones. “I think there is a real opportunity for landscape architects and lighting professionals to help communities understand the relationship between land use and lighting zones and how to address environmental issues with light at night.”

Minimize environment issues of sky glow and light trespass by adhering to the lighting zone levels in designing outdoor lighting that is appropriate for the environment that is being lit.

• Lighting zone 0: None to limited ambient electric light. Application for wetlands, wildlife preserves
• Lighting zone 1: Low ambient electric light. Application in rural communities and residential areas
• Lighting zone 2: Medium ambient electric light. Application in suburban areas. This is the default lighting zone.
• Lighting zone 3: High ambient electric light. Application in entertainment districts and places of nighttime activity
• Lighting zone 4: Very high ambient electric light. Not recommended in any application.

The Quality Lighting Design for People in Outdoor Environments (LP-2-20) standard is available to IES members on the IES website.