As used in this chapter, the following terms shall
have the meanings indicated:
APPROVAL AUTHORITY
The approval authority for this chapter shall be the Town
Board or the Planning Board, unless otherwise specified.
CANDELA (cd)
The standard metric unit of luminous intensity. It is the
power emitted by a light source in a particular direction with wavelengths
weighted by the luminosity function, a standardized model of the sensitivity
of the human eye.
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 article.
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.
ILLUMINANCE
The density of light falling on any point of a surface, usually
measured in footcandles in the United States.
LIGHT
Electromagnetic radiation of any wavelength. The three basic
dimensions of light are: (1) intensity or amplitude, which is related
to the human perception of brightness; (2) frequency or wavelength,
which is perceived as the color of light; and (3) polarization, which
is the angle or vibration of light.
LIGHT FIXTURE
A complete lighting unit including the lamp, together with
the parts designed to distribute the light, position and protect the
lamp and connect the lamp to the power supply. The following terms
describe generic types of lighting fixtures:
(1)
DECORATIVEAn ornamental fixture having an appearance and light distribution intended to provide decoration and visual interest as well as functional illumination.
(2)
SHIELDEDA fixture with cutoff optics that allows no direct light emissions above a vertical cutoff angle of 90º for streetlighting and 80º for all other lighting, through the light fixture's lowest light-emitting part. Any structural part of the light fixture providing this cutoff angle must be permanently affixed.
(3)
UNSHIELDEDA fixture without cutoff optics that allows a direct view to the light source.
LIGHTING PLAN
A lighting plan shall consist of the following information:
(1)
The location of every light fixture and hours
of operation for each.
(2)
A detail of outdoor light fixtures, including
component specifications such as lamps, reflectors, optics, angles
of cutoff, supports, poles and manufacturer's catalog cuts.
(3)
A foundation detail for lightpoles.
(4)
A computer-generated photometric grid showing
footcandle readings every 10 feet and certified by a licensed architect,
engineer or landscape architect.
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 lightbulb 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.
LUMINANCE
The brightness of a source of light. It is a photometric
measure of the density of luminous intensity in a given direction,
specifically the amount of light leaving a surface in a particular
direction, measured in the metric candela per square meter (cd/m2) or the U.S customary unit of footlamberts (fL).
LUMINOUS FLUX
Luminous flux is the measure of the perceived power of light.
SECURITY LIGHTING
Lighting that provides additional safety or security not
already provided by other exterior lighting such as building or parking
lot fixtures.