§ 63.402. Definitions.

Color Rendering Index (CRI) means the scale used to compare the effect of a light source on the color appearance of its surroundings. The higher the score, the more accurately the light source reflects true color.

Cutoff fixture means an outdoor light fixture that provides a cutoff (shielding) of the emitted light. The light distribution may not be greater than 2.5% of the luminaire's lumen output at or above 90 degrees vertical from the nadir and not more than 10% of a luminaire's lumen output at or above 80 degrees vertical from nadir.

Fixture means the assembly that houses a lamp or lamps, and may also include reflectors, mirrors, refractors, lenses, ballasts, housings, and other attachment parts. A fixture is the same as a "luminaire."

Footcandle (sometimes denoted as "f.c.") means the measure of light noted as a unit of illuminance amounting to one lumen per square foot.

Glare means intense and somewhat blinding light, or the sensation produced by brightness within the visual field that is sufficiently greater than the intensity of light to which the human eyes are accustomed or adapted, thereby causing annoyance, discomfort, visual impairment, or loss or reduction of visibility.

Height of fixture means the vertical distance from the normal finished grade directly below the centerline of the luminaire to the top of the light fixture.

Height of the pole means the vertical distance from the finished grade to the highest point inclusive of the pole, finial, fixture, and mounting arm.

Hot spot means an area of very high illumination above normal footcandle levels typically found in an area underneath a luminaire, making normal footcandle levels appear relatively dark.

Illuminance means the quantity of light arriving at a surface divided by the area of the lighted surface, measured in footcandles.

Illuminating Engineering Society of North America (IES or IESNA) means the nonprofit professional society of lighting engineers and specialists that has established recommended design standards for various exterior lighting applications.

Internal louvered optical system means a series of high-speculer (mirror type) stacked louvers that cover the lamp, creating a cutoff, low-glare light pattern.

Lamp means a light bulb.

LED means light-emitting diode.

Light loss factor means the product of all factors that contribute to the lowering of an illumination level, including factors such as reflector degradation, dirt, lamp depreciation, and voltage fluctuations.

Light pollution means any adverse effect of manmade light, often used to denote a brightness of the night sky, commonly known as urban sky glow.

Light trespass means light falling where it is not desired, wanted, or needed.

Lumen means a quantitative unit measuring the amount of light emitted by a lamp or luminaire.

Luminaire means a complete lighting unit consisting of the lamp or light source, fixture, and other parts designed to distribute the light.

Luminance means the quantitative measure of brightness of a light source or an illuminated surface, equal to luminous intensity per unit area of the source or surface viewed from a given angle.

Metal halide (lamp) means a high intensity discharge lamp where the light is produced by radiation from metal-halide vapors, and which renders colors close to their daytime appearance.

Obtrusive light means light which causes annoyance, discomfort, visual impairment, or loss or reduction of visibility.

Photometric plan means a diagram drawn to scale depicting the location of all light poles and building-mounted light fixtures in a specific area and a numerical grid of the maintained lighting levels that the fixtures will produce. All values must be at grade unless otherwise stipulated.

Sag lens, convex lens, or drop-lens means a clear or prismatic refracting lens that extends below the lowest opaque portion of the light fixture.

Shielded means a fixture constructed to have internal or external shields, top and side visors, hoods, or internal louvers to limit glare and light trespass caused by light emission from the luminaire.

Spill light means light that falls outside the property where the luminaire is located.

(Ord. No. 2013-73, § 5, 6-23-2014, Doc. #1406231202)