ordinances
(Continued from page 18)
International Dark-Sky Association (IDA) and
the Illuminating Engineering Society (IES)
co-wrote the Model Lighting Ordinance
(MLO) www.ies.org/PDF/MLO/MLO_FINAL_
June2011.pdf. It includes the use of lighting
zones and luminaire ratings. The MLO will
allow communities to drastically reduce
light pollution and glare and lower excessive
light levels. The recommended practices of
the IES can be met using readily available,
reasonably priced lighting equipment.
Editor���s note: The IDA information sheet ���Economic Issues
in Wasted and Inefficient Outdoor Lighting��� www.darksky.org/
assets/documents/is026.pdf notes the 175 watt dusk-to-dawn
mercury vapor light is a common outdoor fixture that uses about
210 watts (when considering the ballast and other factors).
The paper contends at least 30 percent of this lighting is totally
wasted. Tucson, Ariz. had over 20,000 such lights before a mass
retrofit. The annual operating cost of the mercury fixtures in
Tucson was nearly $1.4 million.
What Can We Do?
Energy, of course, is a big environmental concern, as is the
pollution associated with fossil fuels and generating electricity.
Lighting for safety means illuminating pathways, stairways or
changes in elevation. Security lighting means soft lights along
property borders. Remember to carefully place spotlights. They
can add glare and actually attract intruders. Provide task lighting
(cooking, dining, entertaining) where needed, and, of course,
provide beauty and interest at night.
Less light is more effective. Light only the goals. Use lower
wattage lamps and beam spreads. Direct light only where it���s
needed. That minimizes ���spill��� and increases safety from glare.
Down lighting should be almost straight down to reduce clutter;
up lighting straight up to reduce scatter. Hide the light bulb source
to reduce glare. Incorporate zone controls to turn off unnecessary
light and energy.
Some simple steps during designing the outdoor lighting can
make a big difference. Establish careful lighting goals; use less light;
and direct light carefully. With careful planning, we can mitigate
light pollution.
Information Request # 763
Information Request # 565
growth. Limited epidemiological
studies support the hypothesis that
nighttime lighting and/or repetitive
disruption of circadian rhythms
increases cancer risk.���
Nocturnal
mammals,
birds,
amphibians, reptiles, insects, and
fish experience similar disorientation as humans when there is
too much artificial nighttime light. Behavior governing mating,
migration, sleep and finding food are determined by the length of
nighttime. Light pollution negatively disrupts these age-old patterns,
which in turn causes habitat disturbance, changes in behavior and
impacts survival.
Energy
96 Landscape Architect and Specifier News