When the Airport Authority for the City of Cleveland, Ohio looked into LED parking-garage interior lighting systems, it knew an upgrade would save significant energy compared to the existing metal halides. However, until management saw the actual results, computed real electricity and maintenance savings, and saw obvious day or night drive-lane lighting improvements, they could not have realized the magnitude of energy savings and quality of light improvements for motorists.
The project’s lighting-design goals were straight-forward:
- Substantially reduce energy costs 24/7/365.
- Strive to increase light levels day and night in front of cars entering of leaving the garage.
- Increase light levels at the rear of — and in between — parking spaces.
- Materially reduce routine light-fixture maintenance, malfunctions, and necessary lamp replacements.
- Reduce lighting glare in motorists’ eyes.
- Provide a lighting solution that is not likely to become predictably outdated.
The Airport Authority requested and received proposals from seven lighting manufacturers, all of which offered various alternatives to the present metal-halide lighting. In the end, a new type of specially designed parking-garage luminaire employing LED arrays — the Endura ceiling-mounted LED interior luminaire from Beacon Products, a division of Hubbell Lighting — was chosen.
The consensus of Airport Authority testing was that actual light distribution inside its existing parking garage showed this luminaire to have superior distribution along drive lanes, no “hot spots,” and low-glare high-color-rendition white light. This light projected in frontof drive lanes, avoiding common problems of dark shadows in the line of travel. Ease of retrofit installation on a one-for-one basis in place of existing metal-halide light fixtures and the fact that existing wiring connections could be used were also a plus.
Unique to this particular LED was the company's drive-lane optics feature, which achieves lighting distribution that is particularly effective for typically low mounting heightsfound in public parking garages. The return on investment of 24 months made for a short-term, predictable payback as well.
Peak “candlepower” from the LEDs in the direction motorists are traveling in a parking-garage drive lane is actually reducedto a 55-degree low-glareangle — from a typical 70-degree-high-glarelight angle in drivers’ eyes — in often dark parking garages. The product's on-board occupancy sensor provides additional energy savings by offering three light-level options on each fixture. Parking-garage owners now have a choice for emitted light encompassing both the 55- and 70-degree angles, which can be set or changed to coincide with different hours of daylight or sunlight into a parking garage. Thermally protected against either excessive heat buildup, or snow-belt cold-weather climates, these LEDs typically last 50,000 hours before becoming dimmer to the point replacement is recommended. As a result of the LED retrofit, the Hopkins Airport parking garage has cut lamp replacement times and costs in half.