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A. For the purpose of Sections 17.09.060 through 17.09.069 and 17.93.075, the following definitions apply:

“Accent or architectural lighting” means lighting of building surfaces, landscape features, statues, and similar items for the purpose of decoration, ornamentation, creation of visual hierarchy, sense of liveliness, or other purpose unrelated to safety, business operation, or essential lighting function.

“Backlight” means all the light emanating behind a luminaire.

“BUG rating” means backlight, uplight, and glare rating, which exists on a scale of zero to five and may be used to describe luminaire optical performance in regards to light trespass, sky glow, and high angle brightness control.

Image by City of Ft. Collins, Colorado, and used here with permission.

“Correlated color temperature” (CCT) is a specification of the color appearance of the light emitted by a lamp, relating its color to the color of light from a reference source when heated to a particular temperature, measured in degrees Kelvin (K). The CCT rating for a lamp is a general “warmth” or “coolness” measure of its appearance. Lamps with a CCT rating below three thousand K are usually considered “warm” sources, while those with a CCT above three thousand K are usually considered “cool” in appearance.

“Direct illumination” means the area of intentional illumination emanating from a fixture generally formulated by shielding depth, illumination width, distance, and angle of illumination field, respective to the height and location of the illumination source, in context of property location and grade. This illumination pattern is typically represented by the high intensity cone of light ten percent or greater, emanating and expanding outward from the illumination source. This area is in contrast to the area outside of this high intensity cone, separately defined as light spill. Direct illumination shall be generally interpreted utilizing this formulation by the Zoning Administrator.

Direction Illumination Formulation

“Floodlight” means a fixture or bulb designed to “flood” an area with light. A specific form of bulb or fixture designed to direct its output in a specific direction. Such bulbs are often designated by the manufacturer and are commonly used in residential outdoor lighting.

“Fully shielded fixture” means an outdoor light fixture constructed and mounted so that the installed fixture emits no light above the horizontal plane. Where a light manufacturer provides a BUG rating, the uplight rating (U) must equal zero. Fully shielded light fixtures must be shielded in and of themselves; a light fixture must have the top and sides made of opaque material such that light only escapes through the bottom of the fixture. Fixtures with translucent or transparent sides, or sides with perforations or slits, do not qualify as fully shielded. Any glass or diffuser on the bottom of the fixture must be flush with the fixture (no drop lenses). Surrounding structures, like canopies, eaves, and patio covers, are not to be considered when determining if the fixture is fully shielded, unless specifically allowed. Fully shielded fixtures must be appropriately mounted so that the shielding prevents light from escaping above the horizontal plane and all light is directed downward.

Examples of fully shielded light fixtures.

“Glare” means the visual sensation caused by excessive brightness and which causes annoyance, discomfort, or a disability loss in visual performance or visibility.

“Internally illuminated,” as it relates to signs, means any sign which has a light source entirely enclosed within the sign and not directly visible to the eye.

“Light pollution” means any adverse effect of manmade light. Often used to denote “skyglow” from developed areas, but also includes glare, light trespass, visual clutter and other adverse effects of lighting.

“Light source” means the part of a lighting fixture that produces light, e.g., the bulb, lamp, or chips on board.

“Light trespass” means direct illumination that falls beyond the boundaries of the property where it originates.

“Lumen” means a unit of luminous flux equal to the light emitted by a uniform point source of one candle intensity. Lumens refers to the amount of light emitted by a bulb (more lumens equates to brighter light).

“Manufacturer’s catalog cuts” means a publication or other printed material of a bulb or lighting manufacturer offering visual and technical information about a lighting fixture or bulb.

“Net acre” means a gross acre excluding: public rights-of-way, lands with natural slopes greater than thirty percent, jurisdictional wetlands, lands in the one-hundred-year floodplain, public drinking water supply water sources (recharge areas for the aquifer in the Glen Canyon Formation), lands affected by immitigable geohazards, riparian habitats, archeological sites, and required open space.

“Outdoor light fixture” means a complete lighting unit consisting of a lamp(s) and ballast(s) (when applicable), together with the parts designed to distribute the light, to position and protect the lamps, and to connect the lamps to the power supply. Also known as a luminaire, or simply as a fixture.

“Recreational lighting” means lighting used to illuminate sports fields, ball courts, playgrounds, or similar outdoor recreational facilities.

“Safety lighting” means the minimum amount of lighting required by the Building Official or Zoning Administrator for the purpose of safety, as required or prescribed by standards and regulations specific to the application review. Examples include lighting for ingress/egress, doorways, pathways, and driveways.

“Skyglow” means the brightening of the nighttime sky resulting from the scattering and reflection of artificial light by moisture and dust particles in the atmosphere. Skyglow is caused by light directed or reflected upwards or sideways and reduces one’s ability to view the nighttime sky.

“Spill, light” means illumination that reaches beyond the outside of the direct illumination area.

“Spotlight” means a fixture or bulb designed to light a small area very brightly. See definition of “Floodlight.”

“Temporary lighting” means lighting of a nonpermanent nature, not required for or qualifying as safety lighting, that plugs into an outlet and is not hard-wired.

“Temporary string lighting” means lighting of a nonpermanent nature, not required for or qualifying as safety lighting, that plugs into an outlet and is not hard-wired. Description and qualification of temporary string lighting includes, but is not limited to, ambient, string, café, or bistro lighting; determined by the Zoning Administrator.

“Total, light” means the sum of shielded and unshielded light.

“Total outdoor light output” means the total amount of light, measured in lumens, from all installed outdoor light fixtures on a property, using each manufacturer’s initial rated lumen output.

“Tower” means any monopole, antenna, or the like that exceeds eighteen feet in height.

“Unshielded fixture” means a fixture that has insufficient shielding to prevent light emission above the horizontal.

Examples of unshielded light fixtures.

“Uplight” means all the light emanating above the horizontal plane of a luminaire. (Ord. 23-14, 2023; Ord. 19-03 Att. 1 (part), 2019)