Changing beacon sends weather report
From its construction in 1932 to the late 1970s, the Gulf Tower Building in downtown Pittsburgh, Pennsylvania, USA, was more than just an iconic part of the city skyline—it also served as a rudimentary weather forecast system for pedestrians on the city streets below. Red and blue neon tube arrays mounted on the step-pyramid peak of the 44-story edifice provided the city with a simple, color-coded forecast system: red light signified fair weather ahead, while blue light meant rain or snow. If the light was steady, the temperature was predicted to rise; if flashing, to fall.
When the energy crisis of the 1970s forced the Gulf Oil Company to shut down the tower lights due to public relations concerns, the Pittsburgh tradition of the weather beacon effectively died out. Though the neon tubes were replaced several years later with a slightly more energy-efficient high-pressure sodium vapor lighting system, the color-changing capability required for weather prediction remained out of reach, limited by available technology and energy costs. So when the building owners at Rugby Realty Co., Inc., decided in 2012 to resurrect this much-loved city institution, they turned to a Color Kinetics LED lighting solution that could provide both user-controlled color and a high level of energy efficiency.
The design objective of the installation was to create a dynamic, color-changing light sculpture without incurring high energy costs. To accomplish this, the building owners hired lighting designers Cindy Limauro and Christopher Popowich of C & C Lighting, LLC, in cooperation with Vincent Lighting Systems (VLS), which provided systems integration, programming, and equipment supply services. Limauro and Popowich specified Color Kinetics ColorGraze Powercore luminaires for the retrofit. Consuming a maximum of only 70 W of energy per luminaire, these 1219 mm (4 ft) linear LED wall grazing luminaires provided the energy efficiency and color consistency required for fulfilling the client's vision.
To ensure even illumination, Popowich and Limauro installed the luminaires on existing 51 mm (2 in) tracks spaced approximately 610 mm (2 ft) from the granite limestone walls of the tower's top six stories, with about 610 mm (2 ft) between each luminaire. Each of the 185 installed luminaires is individually controlled by a Pharos LPC 4 controller and Pharos TPC controller for nearly five universes of DMX control.
Taking advantage of this high level of control, the lighting designers devised a more accurate, multifaceted weather display that shows present weather conditions instead of predictions. Under the new system, the lights on the tower's top three stories signify the current temperature, ranging from bright red for 27° C (80° F) or above, to dark blue for -18° C (0° F) or below. The 41st floor represents precipitation in various shades of purple. New to the beacon are indicators for humidity and wind speed, which are represented by shades of green and pink on the 40th and 39th floors, respectively.
To generate these lighting effects, the Pharos LPC 4 controller communicates with a separate Vaisala weather monitor to gather information on the current weather conditions, then triggers a series of lighting timelines based on the date, weather conditions, and any applicable special programs. On a typical day, weather conditions are displayed continually between sunset and sunrise, refreshing every 15 minutes. On a holiday or other special event, an alternate timeline overrides the usual weather display and project a separate program onto the tower, with weather updates featured for only a few minutes at the top of every hour. Vincent Lighting Systems also created an external web interface from which administrators can remotely override the current display settings to celebrate unique events, such as home runs or goals for nearby sports teams such as the Pittsburgh Pirates and the Pittsburgh Penguins. In total, Vincent Lighting Systems programmed nearly 100 separate lighting timelines in accordance with Limauro and Popowich's designs.
Picking the right colors for each floor was one of the main design challenges for this installation, according to Limauro. "The challenge was choosing colors and arranging them in a sequence so that the lighting would always look like a beautiful sculpture no matter what the weather pattern was," Limauro said. Popowich added that "to keep the lighting from being too static, every 15 minutes the top of the beacon cycles through all the temperature colors as visual bell chimes."
Thanks to the retrofit LED lighting system, the building owners were able to introduce the newly christened KDKA-TV Weather Beacon atop the Gulf Tower with a bang on July 4, 2012, with a 30-minute celebratory LED "fireworks" display on the tower's peak. In addition to delivering unprecedented visual power, the new LED solution consumes approximately 75% less energy than the previous high-pressure sodium vapor lighting system.