Definitions. For the purpose of this section, the
following words and phrases shall have the following meanings:
COLOR RENDERING INDEX (CRI)
A measurement of the amount of color shift that objects undergo
when lighted by a light source as compared with the floor of those
same objects when seen under a reference light source of comparable
color temperature. CRI values generally range from zero to 100, where
100 represents incandescent light.
CUTOFF ANGLE
The angle formed by a line drawn from the direction of the
direct light rays at the light source with respect to the vertical,
beyond which no direct light is emitted.
DIRECT LIGHT
Light emitted from the lamp, off the reflector or reflector
diffuser, or through the refractor or diffuser lens, of a luminaire.
FIXTURE
The assembly that houses a lamp or lamps, and which may include
a housing, a mounting bracket or pole socket, a lamp holder, a ballast,
a reflector or mirror, and/or a refractor, lens or diffuser lens.
FOOTCANDLE
A unit of illumination. One footcandle is equal to one lumen
per square foot.
FULLY SHIELDED LUMINAIRE
A lamp and fixture assembly designed with a cutoff angle
of 90°, so that no direct light is emitted above a horizontal
plane.
GLARE
Light emitted from a luminaire with an intensity great enough
to produce annoyance, discomfort, or a reduction in a viewer's ability
to see.
HEIGHT OF LUMINAIRE
The vertical distance from the finished grade of the ground
directly below to the lowest direct light-emitting part of the luminaire.
INDIRECT LIGHT
Direct light that has been reflected off other surfaces not
part of the luminaire.
LAMP
The component of a luminaire that produces the actual light.
LIGHT TRESPASS
The shining of direct light produced by a luminaire beyond
the boundaries of the lot or parcel on which it is located, or on-site
lighting producing more than 0.3 footcandles horizontal brightness
at ground level at any point off premises, except within a street.
LUMEN
A measure of light energy generated by a light source. One
footcandle is one lumen per square foot. For purposes of this bylaw,
the lumen output shall be the initial lumen output of a lamp, as rated
by the manufacturer.
LUMINAIRE
A complete lighting system, including a lamp or lamps and
a fixture.