Maintenance costs were staggering for the 25 year-old lighting fixtures installed in Hillsboro Village — a high traffic, historic retail area adjacent to Vanderbilt University in Nashville, Tenn.
Architecture in the area is traditional, with some buildings dating back as far as 1825. Hillsboro Village also includes a variety of businesses, ranging from coffee shops and restaurants to a bakery, photography studio and old movie theater. Previously, this five-block section was illuminated with futuristic-looking plastic globes vertically mounted on 18-foot spun aluminum poles. Stephen Fuson, senior associate engineer for Nashville Electric Service (NES), said only about half of the fixtures worked, which resulted in very low light levels and many complaints from residents.
“The amount of light provided by the fixtures was almost nil,” Fuson said. “The luminaires had become a maintenance nightmare since parts were no longer available.”
NES, which maintains the lighting fixtures, initiated the retrofit and was responsible for specifying and installing the new luminaires. Once NES selected the fixtures, the units had to be approved by several parties, including a local merchant organization, a representative of the city council and the Nashville Public Works Department. Zoning guidelines also governed any changes made to the lighting system within this historical area.
RSL-200 Series luminaires from Holophane, Newark, Ohio, were selected for the project. The units were chosen because of their decorative top hat-type appearance and the fact the glass refractors could be vertically mounted from the existing aluminum poles. The fixture is very efficient, with the vertical-burning HID lamp distributing 90% of its lumens to the side.
As a test, a single RSL-200 luminaire was installed for members of the merchant organization, city council and the Public Works Department to inspect. The fixture was specified with a 100W high-pressure-sodium lamp — the same lamp used with the plastic globes.
“We essentially doubled the light levels using the same amount of energy,” Fuson said. “The fixtures have a durable glass refractor, which means that maintenance is also reduced.”
Since the luminaires are installed on a state route, state officials had to review and approve the specifications. The entire project meets IES standards, with illumination levels at 1.22 footcandles on average, and two footcandles at the intersections. The fixtures have Type 3 distribution.
The RSL-200 Series fixtures were mounted on existing poles, which resulted in additional cost savings. A total of 40 fixtures were installed, with the poles spaced 75 to 80 feet.
“We compared the cost of replacing the lighting fixtures and the poles with the cost of replacing just the fixtures. The savings were enormous because of the amount of labor involved. The cost of the retrofit was $30,000 compared to more than $100,000 to replace both the fixtures and poles,” Fuson said. Most of the existing wiring was used.
The RSL-200 Series luminaires are illuminated from dusk until dawn and are controlled by photocells located at a relay station that switches the circuits on and off. Three control points are used to facilitate maintenance. NES is maintaining the fixtures.
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