Distracting light which diverts the eye from a visual task.
HID LIGHTINGA 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 LIGHTINGTemporary 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.
IESNAIlluminating Engineering Society of North America (IES or IESNA), an organization that establishes updated standards and illumination guidelines for the lighting industry.
IESNA RECOMMENDED PRACTICESThe publications of the IESNA setting forth illuminance levels for different task areas, e.g., walkways, streets, sportslights, etc.
ILLUMINANCEThe density of light falling on any point of a surface, usually measured in footcandles in the United States. See "footcandle."
LAMPThe generic term for an artificial light source, to be distinguished from the whole assembly (See "fixture."); commonly referred to as the "light bulb."
LIGHTThe form of radiant energy acting on the retina of the eye to make sight possible.
LIGHTING ASSEMBLYAny or all parts of a luminaire that function to produce light, including the bulb, assembly, ballast, mounting features and/or pole.
LIGHT POLLUTIONAny 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 TRESPASSLight projected onto the property of another or into the public right-of-way when it is not required or permitted to do so.
LUMENA 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.
LUMINAIREThe 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.
LUMINANCEThe brightness of a source of light.
MOUNTING HEIGHTThe distance from natural grade to the lowest light-emitting part of the luminaire.
NONCONFORMINGAs used in this article only, lighting which does not meet the requirements and specifications contained herein.
NONESSENTIAL LIGHTINGLighting 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 SHIELDEDA luminaire which is not fully shielded but incorporates a partial shield around the lamp.
PHOTOMETRICSTechnical 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 SIGNAny 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.
SKYGLOWThe 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 LIGHTINGLighting 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 FIXTUREA fixture which, as designed or installed, emits all or part of the light emissions above the lowest light-emitting part of the fixture.