§ 17.48.100. Outdoor lighting standards.
The intent of these standards is to minimize the effects of lighting on the night sky in order to protect views of the night sky, to enhance safety, to minimize glare, and to minimize negative impacts of lighting, including light trespass, on adjacent properties. Exterior lighting shall be evaluated during the development review process to ensure that the functional and security needs of a project are met in a way that will not adversely affect the adjacent properties or the surrounding neighborhood. The degree to which exterior night lighting affects a property owner or neighborhood will be examined based upon the light source, level of illumination, hours of illumination and the need for illumination in relation to the effects of lighting on adjacent property owners and the neighborhood.
A.
Definitions. The following definitions shall be as indicated below:
1.
"Color rendering index (CRI)" means the measured effect of light on objects. To determine the CRI of a lamp, the color appearances of a set of standard color chips are measured with special equipment under a reference light source with the same correlated color temperature as the lamp being evaluated. If the lamp renders the color of the chips identical to the reference light source, the CRI is one hundred (100). If the color rendering differs from the reference light source, the CRI is less than one hundred (100). A low CRI indicates that some color may appear unnatural when illuminated by the lamp.
2.
"Fixture" means luminaire.
3.
"Foot candle" means a quantitative measure of light falling on a given surface equal to one lumen per square foot.
4.
"Full cut-off type fixture" means a luminaire or light fixture that, by design of the fixture housing, does not allow any light dispersion or direct glare to shine above a ninety (90) degree, horizontal plane from the base of the fixture.
5.
"Glare or disability glare" means the direct light emitting from a luminaire that causes reduced vision, or the sensation of annoyance, discomfort, or loss in visual performance and visibility.
6.
"High-pressure sodium (HPS)" means a high intensity discharge lamp where radiation is produced from sodium vapor at relatively high partial pressures. HPS is considered a point source.
7.
"Horizontal illuminance" means the measurement of brightness from a light source, usually measured in foot candles or lumens, which is taken through a light meter's sensor at a horizontal position.
8.
"Lamp or bulb" means the light-producing source installed in the socket portion of the luminaire.
9.
"Lumen" means a quantitative unit measuring the amount of light emitted by a light source. The initial lumen rating is provided by manufacturers with lamp or light bulb packaging.
10.
"Light trespass" means light emitted by a luminaire that shines beyond the boundaries of the property on which the luminaire is located.
11.
"Low-pressure sodium (LPS)" means a discharge lamp where the light is produced by radiation from sodium vapor at a relatively low partial pressure. LPS is a tube source and is a monochromatic light.
12.
"Luminaire" means the complete lighting system, including the lamp and fixture.
13.
"Metal-halide lamp" means a high intensity discharge lamp where the light is produced by radiation from metal-halide vapors.
14.
"Mounting height" means the overall height of the fixture or lamp above the ground.
15.
"Photometry" means the quantitative measurement of light level and distribution.
16.
"Security purpose lighting" means reduced lighting levels, as per subsection (B)(11) of this section, which do not exceed one-half foot candle.
17.
"Shielding" means that no light rays are emitted by a fixture above the horizontal plane running through the lowest point of the fixture where light is emitted.
18.
"Sky glow" means the result of scattered light in the atmosphere above urban areas and the haze or glow of light that currently surrounds populated areas and reduces the ability to view the nighttime sky.
19.
"Uniformity ratio (UR)" means the average level of illumination in relation to the lowest level of illumination for a given area. Example: UR ratio = 4:1 means the highest level of illumination four should be no more than four times the average level of illumination one.
20.
"Uplighting" means any source that distributes illumination above a ninety (90) degree horizontal plane.
The following images are examples of fixtures that have been approved by the International Dark-Sky Association. These fixtures minimize light pollution, glare, and light trespass.
Listing of Lighting Manufacturers with IDA-Approved TM Fixtures
B.
Requirements. All exterior lights and illuminated signs shall meet the following requirements:
1.
Be designed, located, installed and directed in such a manner to prevent objectionable light at and across the property lines and to prevent glare at any location on or off the property.
2.
Be of a white light, such as metal halide, incandescent, or a lamp with a color rendering index above seventy (70).
3.
Not exceed the maintained horizontal illuminance recommendations set by the Illuminating Engineering Society of North America (IESNA) or an average illumination level of one and five-tenths foot candles for the illuminated area based on the initial illuminance level measured following one hundred (100) hours of operation. Undeveloped portions of lots such as open space tracts and/or unbuildable areas such as detention ponds shall not be included in the calculations for the average illuminance level. A uniformity ratio (average to minimum) of illuminance levels of 4:1 is recommended, with a maximum uniformity ratio of 10:1. Illuminance levels shall not exceed one-tenth foot candle as a direct result of the on-site lighting and interior building lighting measured twenty (20) feet beyond the property line of the development site.
4.
Be full cut-off style fixtures for all parking area lighting.
5.
Be illuminated with flush-mounted, flat lens light fixtures for all under-canopy areas.
6.
Be shielded to prevent glare and/or light trespass from all building, site, sign, and aesthetic lighting.
7.
Exclude uplighting, which is prohibited for externally illuminated signs.
8.
Be full cut-off or a fully shielded type fixture (unshielded wall pack style fixtures are not acceptable) for all building lighting including lighting for security. The source of lighting shall be fully shielded from pedestrians and motorists. Fixtures may not be tilted or aimed in a manner that results in light distribution above the horizontal plane unless expressly authorized in this chapter.
9.
Be required to be turned off one hour after business hours, leaving only the necessary lighting for site and building security for all nonessential lighting. For purposes of this subsection, nonessential lighting shall include display, aesthetic, and sign lighting. Security lighting at entrances, stairways and loading docks, as well as limited parking lot lighting, is permitted. The use of motion sensors for security lighting is strongly encouraged. Security lighting shall comply with all applicable provisions contained in this chapter and may not exceed the maximum foot candle level permitted on the site. Outdoor display lots for vehicle sales and leasing shall also comply with the requirements of this subsection by reducing the light levels between 10:00 p.m. and 7:00 a.m. to illumination levels sufficient for security purposes only.
10.
Have the following maximum mounting height:
a.
Twenty-four (24) feet when the fixture is located within seventy-five (75) feet of the site's boundary; or
b.
Thirty-five (35) feet when the fixture is located beyond seventy-five (75) feet from the site's boundary.
11.
Poles supporting light fixtures designed to illuminate parking areas and drive entrances shall be round, unless an alternative is shown to be architecturally superior. The protective pole base may not exceed a height of thirty (30) inches from grade. If the pole is otherwise protected within a parking island or an intervening curb or walkway, no standard is required. A maximum of two light fixtures per pole is recommended for parking lots except for perimeter lighting, which should be limited to one fixture per pole. The fixtures shall not incorporate "basket" features or similar design elements that could deflect light horizontally or upward.
12.
Bollards, or other similar light fixtures that do not exceed four feet in height, intended to illuminate landscape features or walkways, may be permitted as part of the overall lighting plan as part of approval of the site plan or preliminary and/or final PD plan. A maximum of two fixtures per bollard and one lamp per fixture is recommended.
13.
Illumination of a flagpole is permitted, provided that the source of illumination is shielded so the source of illumination is not visible to adjacent property, the lamp is aimed to only illuminate the top of the flagpole and the illumination complies with the provisions of this section.
14.
Illuminance of a building facade to enhance architectural features is permitted provided that downlighted wall-mounted fixtures are used and illuminance is contained completely within the vertical face of the building and does not spill off the building edge. Uplighting may be permitted, provided no illuminance escapes the facade.
C.
Exemptions.
1.
Outdoor lighting for sports and athletic fields shall:
a.
Be installed with internal louvers and be full cut-off or fully shielded fixtures to minimize sky glow;
b.
Not have floodlights aimed above sixty-two (62) degrees;
c.
Have poles used for aerial sports such as baseball or softball at least seventy (70) feet in height to minimize sky glow and the effect upon surrounding uses;
d.
Be shut off within one hour after the game or event has ended and remain extinguished until one hour prior to the commencement of the next event.
2.
Seasonal decorations with individual lights displayed no longer than sixty (60) days per holiday or season.
3.
Incandescent lighting of one hundred fifty (150) watts or fewer for each light fixture, and/or fluorescent lights of twenty (20) watts or fewer per fixture.
4.
Temporary lighting for fire, police, emergency or repair workers.
5.
Temporary lighting for construction activity or periodic events (such as fairs, carnivals and similar temporary uses), provided they do not create disability glare and are approved in advance by the Director of the Development Services or designee.
6.
Street lighting within public rights-of-way if in conformance with the Town's adopted Roadway Standards.
D.
Prohibited Lighting.
1.
Lights that blink, flash, move, revolve, flicker, vary in intensity or color, and chase lighting, except lighting for temporary holiday displays and lighting for public safety.
2.
Lighting that could be confused with a traffic control device.
3.
Lighting of a type, style, or intensity determined to create disability glare which has a detrimental effect on motor vehicle traffic or otherwise creates a public hazard.
4.
Strobe lights, searchlights, beacons and laser light, or similar upward or outward oriented lighting except as provided in this section.
5.
High-intensity floodlighting except as approved for sports facility lighting.
6.
Wall pack light fixtures that are not classified as full cutoff.
E.
Lighting Plan Submission Requirements.
1.
Plans indicating the location, type and height of the luminaires, including both building and ground mounted.
2.
A description of the luminaire, including fixture type, lamps, poles or other supports, and shielding devices, which may be provided as catalogue cut sheets from the manufacturer and a description of light-level-reduction controls for each fixture or grouping of fixtures, and resulting after-hours light levels.
3.
A photometric plan shall be required unless waived at the preapplication meeting. The photometric plan shall exhibit the initial illuminance level calculated at one hundred (100) hours of operation and shall be shown on a maximum of a ten-foot grid.
4.
Additional information as may be required by the Director of Development Services in order to determinate compliance with this section.
5.
The above information shall be submitted to the Town as part of the site plan or preliminary PD or final PD site plan application.
6.
The lighting plan shall be accompanied by a statement that is signed and sealed by a qualified registered professional engineer that the lighting conforms to the requirements in this section and that the photometric plan accurately depicts the light levels.
7.
The Town may seek assistance from a qualified registered professional engineer to evaluate lighting plans and proposed equivalents. The applicant shall pay costs associated with such a review.
F.
Compliance. A site inspection that includes field verification that the lighting conforms to the approved plans may be performed by the Town, in conjunction with the engineer, to assure compliance with the approved lighting plan.
G.
Enforcement. Any person who installs or permits the installation of outdoor lights which do not comply with the performance standards set forth in this section shall be guilty of a Class 1 municipal offense and penalized as provided in Sections 17.88.050 and 17.88.060 of this title.
(Ord. 41-2006: Ord. 13-97 (part): prior code § 13.16.100)
(Ord. No. 09-2010, § 3, 4-19-2010)