Distracting light which diverts the eye from a visual task.
HID LIGHTING
A family of bulb types known as "high intensity discharge,"
including high-pressure sodium, mercury vapor and metal halide. These
types require a warm-up time, usually require a ballast and have a
higher lumen output per watt than incandescent or halogen lamps.
HOLIDAY LIGHTING
Temporary lights used to celebrate holidays. Holiday lighting
includes, but is not limited to, strings of small individual lights,
illuminated menorahs, illuminated nativity scenes, illuminated candles,
and various yard decorations seasonal in nature.
IESNA
Illuminating Engineering Society of North America (IES or
IESNA), an organization that establishes updated standards and illumination
guidelines for the lighting industry.
IESNA RECOMMENDED PRACTICES
The publications of the IESNA setting forth illuminance levels
for different task areas, e.g., walkways, streets, sportslights, etc.
ILLUMINANCE
The density of light falling on any point of a surface, usually
measured in footcandles in the United States. See "footcandle."
LAMP
The generic term for an artificial light source, to be distinguished
from the whole assembly (See "fixture."); commonly referred to as
the "light bulb."
LIGHT
The form of radiant energy acting on the retina of the eye
to make sight possible.
LIGHTING ASSEMBLY
Any or all parts of a luminaire that function to produce
light, including the bulb, assembly, ballast, mounting features and/or
pole.
LIGHT POLLUTION
Any adverse effect of man-made light, including but not limited
to glare, light trespass, skyglow, visual clutter, wasted energy due
to excessive or unnecessary lighting, or any man-made light that unnecessarily
diminishes the ability to view the night sky or is disruptive to flora
and fauna.
LIGHT TRESPASS
Light projected onto the property of another or into the
public right-of-way when it is not required or permitted to do so.
LUMEN
A unit used to measure the actual amount of light that is
produced by a bulb. The lumen quantifies the amount of light energy
produced by a lamp at the lamp, not by the energy input, which is
indicated by the wattage. For example, a seventy-five-watt incandescent
lamp can produce 1,000 lumens while a seventy-watt high-pressure sodium
lamp produces 6,000 lumens. Lumen output is listed by the manufacturer
on the light bulb packaging.
LUMINAIRE
The complete lighting assembly (including the lamp, housing,
ballasts, photocells, reflectors, lenses and shields), including the
support assembly (pole or mounting bracket); a light fixture. For
purposes of determining total light output from a luminaire or light
fixture, lighting assemblies which include multiple unshielded or
partially shielded lamps on a single pole or standard shall be considered
as a single unit.
LUMINANCE
The brightness of a source of light.
MOUNTING HEIGHT
The distance from natural grade to the lowest light-emitting
part of the luminaire.
NONCONFORMING
As used in this article only, lighting which does not meet
the requirements and specifications contained herein.
NONESSENTIAL LIGHTING
Lighting which is unnecessary and not generally useful (e.g.,
decorative and landscape lighting). This includes lighting intended
for a specific task or purpose when said task or purpose is not being
actively performed (e.g., parking lot illumination and wall-mounted
perimeter lights after business hours).
PARTIALLY SHIELDED
A luminaire which is not fully shielded but incorporates
a partial shield around the lamp.
PHOTOMETRICS
Technical test reports that indicate light distribution and
performance from a luminaire. Photometric reports may include candlepower
distribution data, cutoff classifications, footcandle charts, etc.
These are generally available from the luminaire manufacturers.
REPAIR OF A LUMINAIRE OR SIGN
Any service normally provided by a licensed electrician upon
a luminaire or sign. Repair shall be considered to include replacement
or modification of any of the following: poles, mounting arms, housings,
hardware, wiring, ballasts, lenses, reflectors, diffusers, baffles,
shields, sensors, switches, relays, power supplies, and lamp replacement
modules which contain any of the items listed above. Replacement of
a user-serviceable lamp will not by itself be considered a repair.
SKYGLOW
The overhead glow from light emitted sideways and upwards,
including light reflected upward from the ground or other surfaces.
Skyglow is caused by the reflection and scattering of various forms
of light by dust, water and other particles suspended in the atmosphere.
Among other effects, skyglow reduces one's ability to view the night
sky. Different sources of light, in equal quantities, can contribute
differently to sky glow.
TEMPORARY LIGHTING
Lighting that is intended to be used for a specific event
and removed within seven days thereafter.
UNIFORMITY RATIO (U RATIO)
A ratio that describes uniformity of illuminance across an
area. The uniformity ratio may be a ratio of the maximum-to-minimum
illuminance or the average-to-minimum illuminance. For example, if
the Illuminating Engineering Society recommends an average-to-minimum
ratio of 4:1 for a parking lot, the minimum illuminance should be
no less than 1/4 of the average illuminance across the parking lot.
UNSHIELDED FIXTURE
A fixture which, as designed or installed, emits all or part
of the light emissions above the lowest light-emitting part of the
fixture.