Definitions. As used in this section, unless otherwise
expressly stated, the following terms shall have the meanings indicated:
AREA LIGHT
A luminaire designed for illumination of a broad area. Area
lights include, but are not limited to, streetlights, parking lot
lights and yard lights over 1,800 (100 watts incandescent) lumens.
AVERAGE HORIZONTAL FOOTCANDLE
The average level of illuminance for a given situation measured
at ground level with the light meter placed parallel to the ground.
ESSENTIAL LIGHTING
Lighting that is used for a specified period of time, which
is necessary for a specific task or purpose while said task or purpose
is actively being performed. This includes lighting that is necessary
to promote public safety or facilitate public circulation.
EXCESSIVE LIGHTING
Illuminance levels beyond that which is required for safety,
as is indicated on the Table of Limits of Illumination Levels. (See
Table 3 at the end of this chapter).
EXTERIOR LIGHTING
Temporary or permanent lighting equipment that is installed,
located or used in such a manner with the intention to cause light
rays to shine outdoors. Luminaires located indoors that are intended
to light something outside are considered exterior lighting for the
purposes of this section.
FIXTURE (also called "luminaire")
The bulb, the assembly that holds the bulb (or lamp) in a
lighting system, and the mounting apparatus, including reflecting
elements, shielding elements, cover glass or lenses, the ballast,
and the housing.
FLOODLIGHT
A fixture rated to produce over 1,800 lumens (100 watts incandescent),
regardless of the number of bulbs, and is designed to flood an area
with light.
FOOTCANDLE (FC)
The American unit of illuminance (the amount of light falling
on a surface). One footcandle is approximately equal to the illuminance
produced by a light source of one candle, measured on a surface one
foot away from the source. Horizontal footcandles measure the illumination
striking a horizontal plane. Footcandle values can be measured directly
with certain handheld incident light meters.
FULL CUTOFF (FCO)
A classification for a luminaire designed and installed where
no light is emitted at or above a horizontal plane running through
the lowest point on the luminaire. In addition, the luminous intensity
(as measured in candelas) emitted at any angle from 80° up to
90° cannot exceed a numerical value equal to 10% of the lumen
rating of the lamp, as reported in a photometric report from the manufacturer
as produced by an independent lab. A cutoff, or semicutoff, design
allows a restricted amount of light emitted above the horizontal,
and a noncutoff provides no restriction against light emitted above
the horizontal.
FULLY SHIELDED
A luminaire constructed, lamped, and installed in such a
manner that all light emitted by it, either directly from the lamp
or a diffusing element, or indirectly by reflection or refraction
from any part of the luminaire, is projected below the horizontal.
A full cutoff fixture is also fully shielded, but without any restrictions
on light distribution below the horizontal plane, and it can be identified
without a manufacturer's report.
GLARE
Stray, unshielded light striking the eye that may result
in:
(1)
Nuisance or annoyance, such as light falling
across property lines;
(2)
Discomfort, such as bright light causing squinting
of the eyes;
(3)
Disability, such as bright light reducing the
ability of the eyes to see into shadows and visual performance; or
(4)
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 warmup time, usually require a ballast, and have a
higher lumen output per wan 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.
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 skyglow.
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.