Grays Bridge MN LED Luminaires Case Study
Fixtures reduce energy usage 50 percent, provide nautical feel
The tree-dotted shores of Lake Minnetonka represent one of Minnesota’s most posh residential areas. Located near the City of Minnetonka and just eight miles west of Minneapolis, the lakeshore is lined with million dollar-plus estates, with residents relying on Highway 101—the only road on the east side of the lake—to access major roads and highways.
The stone-faced 300-foot long Gray’s Bridge is part of Highway 101 and spans a large water channel leading to the waters of Gray’s Bay. Minnetonka recently hired Energy Management Solutions, Inc., Chanhassen, Minnesota to decrease the city’s overall energy consumption. The company identified the high pressure sodium lighting system that previously illuminated Gray’s Bridge as a candidate for replacement.
Energy Management Solutions recommended installing GlasWerks® LED luminaires from Holophane to cut energy usage and maintenance requirements.
“Good lighting is paramount to Gray’s Bridge because of the volume of lake, vehicle and foot traffic,” said Brian Smith, building division foreman for the City of Minnetonka. “Before the lighting retrofit, residents of the area had also expressed concern about the appearance of the roadway and neighborhood.”
Bern style GlasWerks luminaires feature a contemporary yet nautical feel to complement the lake environment, which includes a marina located on the bridge’s south side. Kilmer Electric, Minneapolis, installed the lighting fixtures on existing black shepherd’s crook poles mounted on pilasters that are part of the bridge’s structural support. One fixture is mounted per pole at approximately 20 feet, with the poles spaced 50 to 75 apart—depending on the pilaster locations.
According to Tanuj Gulati, senior energy engineer for Energy Management Solutions, the lighting system was specifically designed to light the roadway, where illumination levels measure 2 footcandles. Any illumination that shines onto the sidewalk located on the bridge’s northeast side is an added bonus.“The GlasWerks fixtures throw more uniform illumination a greater distance than the high pressure sodium system they replaced,” Gulati said. “The luminaires’ white light enhances driver and pedestrian safety and even though the fixtures are fully shielded they provide a nice landmark for boaters on the lake after dark.”
“Fixture installation progressed smoothly,” Smith said. “The lighting system helps us meet our goals by reducing energy consumption by more than 50 percent.”
GlasWerks luminaires are designed for reliable, long-term performance, with the city expecting the fixtures to require virtually no maintenance during the next 10 years or longer. The luminaires are lit approximately 4,000 hours each year and controlled by a photocell located at the marina.
Smith said the city will consider installing GlasWerks luminaires for future lighting projects.
Products Included In This Solution
GlasWerks LED
