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HomeMy WebLinkAbout2018-02-15 PACKET 08.2.B.MmCottage Grove here Pride and PCp59erity Meet To: Planning Commission From: Jennifer Levitt, P.E., Community Development Director/City Engineer Nathan Estrem, P.E., Project Engineer Date: January 18, 2018 Subject: Light Emitting Diode (LED) Lighting Background: Concern over brightness of new City street light fixtures has been brought to the attention of City staff. The City maintains more than 3,890 streetlights. With the City's goal to improve energy ef- ficiency and reduce maintenance costs as it relates to City infrastructure, the City Policy has been to install light emitting diode (LED) lighting at all new City infrastructure projects, and re- place old light fixtures with LED fixtures in conjunction with pavement management projects, collector roadway lighting improvement projects, and other reconstruction projects. Since the policy amendment in 2014, the City has converted 371 high pressure sodium (HPS) street lights to LED and installed LED light fixtures at all new residential developments including Grayson Meadow, Eastridge Woods 4th and 5th Additions, and Summers Landing 1st Addition. Discussion: LED light fixtures are far more energy efficient and have much longer anticipated life expectancy than HPS light fixtures. A typical HPS light fixture has an expected useful life of 15,000 to 35,000 hours (3.75 to 5.8 years). LED light fixtures have expected useful lives of 65,000 to 100,000 hours (16.25 to 25 years). This extended life expectancy will lead to a reduction in maintenance and replacement costs. Additionally, the turn -on time of an LED light is nearly instantaneous (<0.1 second) because LEDs do not require a ballast to regulate electrical current. HPS lighting can take 15 to 20 minutes to heat up enough to emit light due to the need for ballasts. These difference are part of the reason that LED light fixtures consume 40 to 80 percent less energy than HPS fixtures. Aside from being more efficient, LED lights emit a wider correlated color temperature (CCT) than HSP lighting, which enables better color identification and improves nighttime visibility and security. This is because LED lights utilize a series of electrically charged diodes arranged in a variety of patterns, depending on the application, so the light can be directed where needed re- sulting in less overlap or spill-over lighting. Conversely, HPS lighting utilizes a single filament to heat the high pressure sodium within the light fixture and projects light in all directions. This lim- its the visible light spectrum from HPS to hues of yellow making true color identification difficult. Below is a contrast of the difference in nighttime visibility of the same intersection illuminated by LED (left) versus HPS (right): Planning Commission Light Emitting Diode (LED) Lighting January 18, 2018 Page 2 of 3 Common complaints regarding LED lighting are related to brightness and glare. Brightness complaints are typically a result of improper installation of the fixture. This can occur when the LED array and the fixture housing are not aligned according to the installation instructions. The improper alignment often results in light projecting away from the intended lighting area. This condition is often remedied by realignment of the light fixture components. Complaints related to glare can be attributed to the intensity of the light generated by the LED fixture in relation to the HIPS light fixture it may have replaced or the lighting to which residents may have been accustomed. Specific complaints related to glare may be attributed to the instal- lation of replacement LEDs with a similar wattage to the HIPS lights they replaced. Due to LED light efficiency, less wattage is required to produce more light. LED light fixtures produce light temperatures between 4,200° Kelvin and 5,000° Kelvin, which allows more of the visible spec- trum of colors, whereas HIPS light fixtures produce a light temperature of approximately 2,200° Kelvin. Color temperature and color perception are an inverse relationship. The higher the color temperature, the cooler or more blue the light appears. The cooler the color temperature, the warmer, or more amber the color appears. This difference can be seen in the above picture. As LED technology improves, more options for color temperature reduction will become available. The City will continue to investigate the best options in regard to color temperature and bright- ness when considering replacement of existing light fixtures and installation of new light fixtures. In an effort to reduce brightness and glare, the City is in the process of updating the Standard Detail and Specification for light fixtures. The City will continue to check for proper fixture instal- lation, and if necessary, install dimmer hardware to reduce brightness and glare on light fixtures identified as having issues. City staff will continue to respond to complaints related to street lighting as they are received and evaluate existing identified neighborhoods for compliance with the City's new lighting standards. Planning Commission Light Emitting Diode (LED) Lighting January 18, 2018 Page 3 of 3 Given the large initial capital investment required to conduct a wholesale replacement of the re- maining HIPS fixtures to LED, the City will continue phasing HIPS to LED replacements annually as part of pavement management and collector roadway lighting improvement projects. For 2018, the City plans to replace approximately 36 collector road light fixtures: 21 light fixtures on 80th Street and 15 light fixtures in the commercial district of Jamaica Avenue and Keats Ave- nue. Additionally, in an effort to improve reliability of light fixture electrical feeds, the City will continue to replace direct bury electrical wire with conduit installed behind the curb in conjunc- tion with pavement management projects. The City will continue to require installation of LED light fixtures and conduit within new development areas and redevelopment. Due to the longer life expectancy, decreased maintenance, higher quality light, and higher en- ergy efficiency, it is not recommended to depart from the City's policy in regard to street light installation and replacement.