Authorization for street light installations shall occur at such time as:
A. The developer requests the installation of street lights. The town is billed for the lease once the lights are installed and operational, unless upon approval of the UDO Administrator, the developer is allowed to continue paying BEMC. The lights must be operational prior to the issuance of any certificates of occupancy being issued;
B. Certificate of occupancy is issued in the immediate area of the proposed street light location; or
C. Thoroughfare, marginal access street, or collector street is constructed or widened as a part of development. Thoroughfares, marginal access streets, and collector streets that are constructed or widened by the town shall be lighted immediately after construction.
Part III. DEFINITIONS AND ABBREVIATIONS
BACK LIGHT. The luminaire lumens distributed behind a luminaire between 0 and 90 degrees vertical. Subdivisions are considered to be BL (low) from 0-30 degrees vertical; BM (mid) from 30-60 degrees vertical; BH (high) from 60-80 degrees vertical; BVH (very high) from 80-90 degrees vertical.
BUG RATING. The IES rating system for luminaires that measures backlight, uplight, and glare using three individual ratings, respectively.
CANDLEPOWER. The density of luminous flux, or light energy, per solid angle (directional cone of light) expressed as lumens per steradian, or candela. CANDLEPOWER is normally associated with a directional type fixture such as a floodlight. Also called LUMINOUS INTENSITY.
CROSSWALK. Any portion of a roadway at an intersection or elsewhere distinctly indicated as a pedestrian crossing by lines on the surface which may be supplemented by contrasting pavement texture, style, or color.
CUTOFF. A luminaire light distribution where the candela per 1,000 lamp lumens does not numerically exceed 25 (2.5%) at an angle at or above 90 degrees above nadir, and 100 (10%) at a vertical angle at or above 80 degrees above nadir. This applies to all lateral angles around the luminaire.
DIRECT LIGHT. Light emitted directly from the lamp, off of the reflector or reflector diffuser, or through the refractor or diffuser lens, of a luminaire.
FIXTURE. The assembly that houses the lamp or lamps and can include all or some of the following parts: housing, mounting bracket or pole, socket, lamp holder, ballast, reflector or mirror, and/or refractor or lens.
FLOOD LIGHT or SPOTLIGHT. Any light fixture or lamp that incorporates a reflector or a refractor to concentrate the light output into a directed beam in a particular direction with a wide or narrow beam. (These fixtures and lamp types are not allowed within the town.)
FOOTCANDLE (FC). The imperial unit of measurement of illuminance (E) relative to square-feet. 1 fc = 0.0929 lx.
FULL CUTOFF. A luminaire light distribution where zero candela intensity occurs at or above an angle of 90 degrees above nadir. Additionally, the candela per 1,000 lamp lumens does not numerically exceed 100 (10%) at a vertical angle of 80 degrees above nadir. This applies to all lateral angles around the luminaire.
FULLY SHIELDED LIGHTS. Outdoor light fixtures shielded or constructed so that no light rays are emitted by the installed fixture at angles above the horizontal plane.
GLARE. The sensation produced by luminance within the visual field that is sufficiently greater than the luminance to with the eyes are adapted (subjective brightness) causing annoyance, discomfort (discomfort glare), or loss of visual performance and visibility (disability glare).
IES. The Illuminating Engineering Society is the recognized technical authority on illumination, a not-for-profit professional organization of lighting practioners with the mission to improve the lighted environment by bringing together those with lighting knowledge and by translating that knowledge into actions that benefit the public.
ILLUMINANCE (E). The amount of light (luminous flux) falling on a surface located at a point and relative to a direction as expressed in lumens per unit area, typically footcandles or lux.
ILLUMINANCE, AVERAGE (EAVE). The average of a number of points of footcandle calculations or footcandle readings in a given area. They could be initial or maintained.
ILLUMINANCE, AVERAGE MAINTAINED. The average of a number of points of footcandle calculations or footcandle readings in a given area which have been adjusted to account for maintenance which includes luminaire dirt depreciation (LDD) and lamp lumen depreciation (LLD).
ILLUMINANCE, AVERAGE TO MINIMUM. The ratio of average footcandle value to the minimum footcandle value at a point per a calculation or reading for a given area. This ratio is generally maintained footcandles but could be initial. This ratio is an indicator of lighting uniformity. The lower the ratio the better the uniformity.
ILLUMINANCE, INITIAL (EINI). Footcandles calculated with no adjustment for dirt buildup in the fixture or lamp lumen depreciation. Initial footcandles should be measured when a lighting system is new and after 100 hours of lamp burn-in time. Car dealerships are often designed to initial footcandles.
ILLUMINANCE, MAINTAINED. Footcandles that are calculated with an adjustment for a maintenance factor to include dirt buildup in the luminaire (fixture) and lamp output depreciation. The system is in effect over designed initially and then over time falls to a maintained footcandle level. The maintenance factor used in the design process to account for this depreciation cannot be lower than 0.72 for high-pressure sodium and 0.64 for metal halide and mercury vapor.
ILLUMINANCE, MAXIMUM. The maximum footcandle point calculation or reading in a given area. The maximum is generally maintained footcandles but could be initial.
ILLUMINANCE, MAXIMUM TO MINIMUM. The ratio of the maximum footcandle point calculation or reading to the minimum footcandle point calculation or reading for a given area. This ratio is generally maintained footcandles but could be initial. This ratio is an indicator of lighting uniformity. The lower the ratio the better the uniformity.
ILLUMINANCE, MINIMUM. The minimum footcandle point calculation or reading in a given area. The minimum is generally maintained footcandles but could be initial.
INDIRECT LIGHT. Direct light that has been reflected or has scattered off of other surfaces.
INTERNAL REFRACTIVE LENS. A glass or plastic lens installed between the lamp and the sections of the outer fixture globe or enclosure. Refractive refers to the redirection (bending) of the light as it goes through the lens, softening and spreading the light being distributed from the light source thereby reducing direct glare.
LAMP. The component of a luminaire that produces visible fight.
LIGHT LOSS FACTOR (LLF). A factor used in a lighting calculation to approximate changes in light output of the system that occur over a given period of time that is an aggregate of multiple factors such as temperature and voltage variations, dirt accumulation (luminaire dirt depreciation, LDD), luminaire surface depreciation, or reduced lamp output as the source ages (lamp lumen depreciation, LLD).
LIGHT POLLUTION. The added sky brightness caused by the scattering of electric light into the atmosphere, often referred to as sky glow.
LIGHT SOURCE. The element of a lighting fixture that is the point of origin of the lumens emitted by the fixture.
LIGHT TRESPASS. The effect of light that strays from the intended purpose and causes annoyance, loss of privacy, or loss of intended functionality or is a determent to visual performance. A luminaire producing light beyond the boundaries of the property on which it is located and intended is considered to be LIGHT TRESPASS.
LUMEN (lm). The SI unit of luminous flux total quantity of light emitted from a light source. One footcandle is one lumen per square foot. For the purpose of this ordinance, the lumen-output values shall be the initial lumen output ratings of a lamp as listed in a lamp catalog.
LUMINAIRE. A complete lighting unit consisting of a lamp or lamps together with the parts designed to distribute the light, to position and protect the lamps, and to connect the lamps to the power supply.
LUMINANCE. The quantity of light reflected or emitted toward an observer; what an observer sees whether reflected from an object or coming directly from a source; commonly referred to as brightness. All surfaces have some reflecting qualities and therefore have LUMINANCE, light surfaces being more reflective than dark surfaces.
LUX (lx). The SI unit of measurement of illuminance relative to square-meters. 1 lx = 10.76 fc.
MOUNTING HEIGHT OF LUMINAIRE. The vertical distance between the ground, or other referenced task plane, and the center of the apparent light source of the luminaire.
NON-CUTOFF. A luminaire light distribution where there is no candela limitation in the zone above maximum candela.
OUTDOOR LIGHTING. The nighttime illumination of an outside area or object by any human- made device located outdoors or indoors that produces light by any means.
OUTDOOR LIGHTING, TEMPORARY. The nighttime illumination of an outside area or object by any human-made device located outdoors that produces light by any means for a limited period of time. This period can be specified by the town.
PRE-EXISTING LUMINARIES. Luminaries not conforming to this ordinance that were in place at the time this ordinance was voted into effect.
ROAD CLASSIFICATION, COLLECTOR. Roads servicing traffic between major and local streets. These are streets used mainly for traffic movement within residential, commercial, and industrial areas.
ROAD CLASSIFICATION, LOCAL. Streets used primarily for direct access to residential, commercial, industrial, or other abutting property.
ROAD CLASSIFICATION, MAJOR. The part of a roadway system that serves as the principal network for through-traffic flow connecting areas of principal traffic generation and important rural roadways entering and leaving a city. These roads are also referred to as “thoroughfares” or “preferentials”.
ROADWAY LIGHTING. Lighting provided for freeways, expressways, limited access roadways, and roads on which pedestrians, cyclists, and parked vehicles are generally not present to help motorists remain on the road and detect obstacles within and beyond the range of vehicle headlamps. (See also STREET LIGHTING).
SAG (VERTICAL) CURVE. A vertical curve that connects a segment of roadway with a segment of roadway that has a more positive grade, (downhill to level, downhill to uphill.)
SEMI-CUTOFF. A luminaire light distribution where the candela per 1,000 lamp lumens does not numerically exceed 50 (5.0%) at an angle at or above 90 degrees above nadir, and 200 (20%) at a vertical angle at or above 80 degrees above nadir. This applies to all lateral angles around the luminaire.
STREET LIGHTING. Lighting provided for major, collector, and local roads where pedestrians and cyclists are generally present to help motorists identify obstacles, provide adequate visibility of pedestrians and cyclists, and assist in visual search tasks both on and adjacent to the street.
UNIFORMITY. A description of the smoothness of the lighting pattern or the degree of intensity of light and dark areas in the roadway or area to be lighted. UNIFORMITY is usually expressed as a ratio such as max to min or average to min. The lower the ratio the more uniform the lighting design.
UPLIGHT. The luminaire lumens distributed above a luminaire between 90 and 180 degrees vertical. Subdivisions are considered to be UL (low) from 90-100 degrees vertical; UH (high) from 100- 180 degrees vertical.
VEILING LUMINANCE. A luminance superimposed on the retinal image which reduces its contrast. It is this veiling effect produced by bright sources or areas in the visual field that results in decreased visual performance and visibility. An example of this is this would be with oncoming automobile headlights.
VEILING LUMINANCE RATIO. Ratio of the maximum veiling luminance of the light fixture in question in the area that is being lighted to the average luminance of the area being lighted. The higher the ratio the worse the disability glare and the lower the visibility. IESNA-RP-8-00 recommended ratios are 0.3 (0.3 to 1) for expressways and major roadways and 0.4 (0.4 to 1) for collector and local roads. (The determination of this ratio is a function of a combination of the road width pole spacing, rated lamp lumens, mounting height, and the classification or type of fixture [cutoff, semi-cutoff, or non-cutoff]. Problems occur most often with non-cutoff post mounted fixtures at low mounting heights [less than 20 feet] with low to medium lumen packages. To meet the ratio requirements, the spacing of poles may need to be as close as 25 or 30 feet staggered spacing with the use of 9,500 lumens in a non-cutoff post- mounted acorn fixture. Wider spacing can be accomplished with cutoff type distribution fixtures.)
WALL PACK. A type of light fixture typically flush-mounted on a vertical wall surface.
WIDE-BODY REFRACTIVE GLOBE. A translucent lamp enclosure used with some outdoor fixtures to provide a decorative look (including, but not limited to, acorn- and carriage light-style fixtures). WIDE-BODY refers to a wider than average size globe (greater than 15.75 inches in diameter). REFRACTIVE refers to the redirection (bending) of the light as it goes through the lens, rendering the light fixture more effective. WIDE-BODY REFRACTIVE GLOBES are intended to soften and spread the light being distributed from the light source thereby reducing direct glare.
(Ord. passed 2-3-2021)