D E V E L O P M E N T S TA N D A R D S G U ID E
STANDARD #10: OUTDOOR LIGHTING
and results in “hotspots”. This is an increasingly common
Lighting is an important part of development and, when used occurrence.
carefully, it enhances the community. However, outdoor
Competing light levels, or lack of uniformity, detract from
lighting is often difficult to understand and visualize in a
the sense of safety and security of an area, as well as the
design. When designing for outdoor lighting, consider the
overall character of the project. Security is one the most
following:
common reasons for adding light to a project. Remember: it
is the quality of the light, not quantity, that improves the
• What is the purpose of the light?
sense of security the most.
• What kind of light is already available?
• Why is more outdoor light needed - will it improve
Energy Efficiency
visibility or make the property more secure?
Not all lights are created equal. There are wide ranges in
• How much light is really needed, and what are the
efficiency
based on both the amount of light produced per
long-term energy costs?
watt, and the life-span of the lamp. Factors which affect
energy efficiency include the how much light is used (see
LIGHTING CONSIDERATIONS
There are several factors to consider before adding light to a Illumination above), the amount of misdirected light (see
Glare above) and the color of light desired (see Color below).
property. It is the combination of all of these factors that
GUIDING QUESTIONS
results in a quality lighting design that benefits the project
and the community.
Color
The color of the light used affects how objects appear
compared to normal sunlight. The color chosen for lighting is
Illumination Level
The level of illumination refers to the amount of light needed often based on two factors - the task and energy usage.
for the task. Many people are led to believe that more light is Incandescent lamps are the closest to natural light, yet these
better. This is not necessarily true. The light level on a typical are the least energy efficient. High pressure sodium (HPS)
sunny day at the beach is 30,000 footcandles: on a cloudy day lamps, while very efficient and long lasting, emit an orangeyellow light that distorts color as well as the ability to
it’s 1,500 footcandles. However, you only need a tenth of a
identify
features at a distance. Metal halide lamps emit a cool
footcandle to read the serial number on a dollar bill. Think
white
light
which makes for more accurate object and color
“less is more.”
identification.
Glare
When light shines directly into your eye, visibility is reduced
due to glare. Glare causes contrasts to be washed out and
objects become much harder to see. Causes of glare include
using too much light and improperly aimed fixtures. The
solution is to use only as much light as is needed, direct the
light to where it is needed, and shield the lamp from view.
Full cutoff fixtures are shielded so that the light is focused
exactly where it is needed.
Uniformity
Uniformity is the evenness of lighting across the site or
project and while the human eye can adjust to a wide range of
light conditions, it can only adapt to one at a time - typically
the brightest. As a result, everything else appears very dark in
comparison. For example, if a neighbor has a really bright
light in their yard, the adjacent neighbor’s yard by
comparison probably appears to be very dark. Creating areas
that are very bright and very dark is called “over-lighting”
DESIGN OBJECTIVES
♦ The lighting level should be appropriate to the
task.
♦ Remember, less is more!
♦ Lighting levels should be reasonably uniform to
avoid very bright and very dark areas.
♦ The lamp should make objects appear as close to a
natural color as possible and provide high energy
efficiency.
♦ The fixture should minimize glare and spill-over
onto adjacent property and into the sky. This can
be done through the use of full cutoff fixtures
and/or reflectors in the lamp.
♦ The mounting height of the fixture should be as low
as possible.
♦ Sensor-controlled lights (typically heat or motion)
should be considered for security lighting and for
energy savings.
D E V E L O P M E N T S TA N D A R D S G U ID E
STANDARD #10: OUTDOOR LIGHTING
As part of Standard #10, the Planning Board requires fully shielded (full-cutoff) fixtures. Fully shielded fixtures prevent glare and
spillover onto adjacent properties or into the sky. Fully shielded lights also help create greater uniformity of light, reduce glare, and can
reduce the number of watts needed, resulting in energy conservation and the amount of wasted light.
The top photo illustrates two factors to consider when designing
lighting: glare and uniformity. The top photo has high glare, nonrecessed fixtures under the canopy. Note how bright the lights
themselves are and how dark the pump area is.
The bottom photograph shows the same gas station canopy with
full-cutoff, recessed fixtures. Note how the light is directed
effectively towards the area needing the lighting: the gas pumps.
Images from http://www.skyandtelescope.com
The above illustration shows some common examples of
poor lighting fixtures and good lighting fixtures.
Images from the New England Light Pollution Advisory Group website
at http://www.cfa.harvard.edu/nelpag/nelpag.html