Definitions. Unless specifically defined below, words and phrases used in this section shall be interpreted to have common English usage, to give effect to the purposes set forth in Subsection
1 above and to provide reasonable application of this section. As used in this section, the following terms shall have the meanings indicated, unless a different meaning clearly appears from the context:
[Amended by Ord. 2010-09, 11/3/2010; by Ord. 2017-05, 11/28/2017]
BUG RATING
The IES designation of a luminaire's light distribution in three directions: B = Backwards, U = Upwards (90° and above), G = Glare Zone Forward (80° to 90°).
CORRELATED COLOR TEMPERATURE (CCT)
The color temperature of the light source measured in degrees Kelvin. High CCT, e.g., 6000K, indicates cold white light, low CCT, e.g., 3000K, indicates warmer light in the red end of the spectrum.
CUTOFF ANGLE
Of a luminaire, the angle, measured up from the nadir, between the vertical axis and the first line of sight at which the bare source is not visible.
DIRECT LIGHT
Light emitted directly from the lamp or off of the reflector or reflector diffuser, or through the refractor or diffuser lens of a luminaire.
FIXTURE or LIGHT FIXTURE
See "luminaire."
FLOOD OR SPOT LIGHT
Any light fixture or lamp that incorporates a reflector or a refractor to concentrate light output into a directed beam in a particular direction.
FOOTCANDLE
A unit of illuminance. One footcandle is one lumen per square foot (1m/ft2) of incident light.
FULLY SHIELDED LIGHTS
Outdoor light fixtures shielded, aimed, mounted or constructed in such a manner that all light emitted by the fixture, either directly or from the lamp or a diffusing element or indirectly by reflection or refraction, is projected below the horizontal plane through the fixture's lowest light emitting part as certified by a photometric test report.
GLARE
The sensation produced by the luminances within the visual field that is sufficiently greater than that to which the eyes are adapted to cause annoyance, discomfort or loss in visual performance or visibility. Unlike illuminance, glare does not decrease as viewing distance from sources increase, only apparent size of the source of glare decreases with increased viewing distance.
HEIGHT OF LUMINAIRE
The height of a luminaire shall be the vertical distance from finished grade directly below the center line of the luminaire to the lowest direct-light-emitting part of the luminaire.
ILLUMINANCE
The quantity of incident light measured in footcandles or lux.
ILLUMINATION
An alternative term for illuminance. Commonly used in a qualitative or general sense to designate the act of illuminating or the state of being illuminated.
INDIRECT LIGHT
Direct light that has been reflected or has scattered off of other surfaces.
LAMP
The component of a luminaire that produces light. A generic term for a man-made source of light, i.e., a light bulb.
LIGHT-EMITTING DIODE (LED) SOLID STATE LIGHTING
The latest light source to be used for outdoor lighting, featuring improved efficacy and directional control and longer life.
LIGHT LOSS FACTOR (LLF)
The ratio of illuminance for a given area to the value that would occur if lamps operated at their initial rated lumen output and if no system variation or depreciation had occurred.
LIGHT TRESPASS
The shining of light produced by a luminaire beyond the boundaries of the property on which it is located.
LUMEN
A standard unit of luminous flux. Photometrically, it is the luminous flux emitted within a unit solid angle (one steradian) by a point source having a uniform luminous intensity of one candela. One footcandle is one lumen per square foot. For the purposes of this section, the lumen-output values shall be the initial lumen output ratings of a lamp, as specified by the manufacturer of the lamp.
LUMINANCE
The physical and measurable quantity corresponding to the brightness of a surface in a specific area from which light is emitted or reflected (e.g., lamp, luminaire, reflecting material). Can be measured in candelas per square meter (cd/m2) or footlamberts.
LUMINAIRE
A complete lighting unit consisting of one or more lamps together with the fixture, other parts designed to control the light distribution and other mechanical and electrical components.
LUMINAIRE, CUTOFF
A luminaire whose light distribution at or above an angle of 90° above nadir does not numerically exceed 25 candela per 1,000 lamp lumens (2.5%), and does not numerically exceed 100 candela per 1,000 lamp lumens (10%) at or above a vertical angle 80° above nadir. This applies to all lateral angles around the luminaire.
LUMINAIRE, FULL CUTOFF
A luminaire whose light distribution at or above an angle of 90° above nadir has zero candela intensity and does not numerically exceed 100 candela per 1,000 lamp lumens (10%) at or above a vertical angle 80° above nadir. This applies to all lateral angles around the luminaire.
LUMINAIRE, FULLY SHIELDED
A luminaire whose light distribution at or above an angle of 90° above nadir has zero candela intensity but which does not have a glare zone restriction.
LUX
The standard unit of illuminance. One lux is one lumen per square meter (1m/m2) and the nominal equivalent at 0.1 footcandle.
NIGHTTIME
The hours between the end of evening civil twilight and the beginning of morning civil twilight. Civil twilight ends in the evening when the center of the sun's disk is 6° below the horizon and begins in the morning when the center of the suns disk is 6° below the horizon.
OUTDOOR LIGHTING
The nighttime illumination of an outside area or object by any man-made device that produces light by any means regardless of whether the actual source of the light is outside or within a structure.
OUTDOOR LIGHTING, TEMPORARY
Outdoor lighting that is used for a period of less than seven days, with at least 180 days passing before being used again or used annually for a period of 30 days or less.