INSIDE THE COLOR-CHANGING COLUMNS AT LOS ANGELES INTERNATIONAL AIRPORT
"Design one and you've designed them all was the impression we had originally," says LD Jeremy Windle with a sigh. Thirty freestanding glass columns, or pylons, ranging from 25' to over 100' in height (8-30m), were planned for installation along the roadways to greet visitors at the Los Angeles International Airport as they approach the terminal hub. "At night, all the columns were to be internally illuminated," adds Windle, "and capable of changing color remotely. Simple enough, or so it would seem."
Windle and assistant designer Erin Powell, under the direction of principal designer Dawn Hollingsworth of LA-based Moody Ravitz Hollingsworth (MRH) Lighting Design, provided design/build services to implement the multimillion-dollar LAX Gateway Enhancement Project, which opened officially on August 8. "The initial lighting concept, as well as the performance specifications," explains Hollingsworth, "were developed by Chip Israel of Long Beach, CA-based Lighting Design Alliance, who served as lighting consultant for the project design team assembled by principal designer and architect Ted Tanaka. The design intent was to provide a layered effect, blending multiple colors in the large columns and a single color in the small columns.
"Fluorescent, neon, and cold cathode were the initial lighting sources looked at," she continues, "and we completed an extensive research period prior to bidding the project, including trips to Las Vegas to take photometric measurements of other equipment installations. Our first challenge was the brightness specification, which was quite high, especially for the heavily saturated colors."
California-based electrical contractor Helix Electric and electrical consultant Boyle Engineering partnered with MRH to provide design/build services, and after an aggressive bidding phase the team was awarded the contract in early October 1999. "We tested fluorescent fixtures and modeled the number of lamps we thought would be required to make a smooth wash," notes Windle, "but the total distance from the outer glass to the inner steel was only 15" on the small pylons and 26" on the large. There just wasn't enough room to get rid of the lamp image. Then there was the problem of where to put the dimmers, the substantial electrical load on the DWP (Department of Water and Power), and so on."
Coated with safety film and two layers of diffusion, each of the glass panels are point-supported, which provides gaps to allow for seismic movement and convection cooling. With engineering calculations that predicted internal temperatures climbing as high as 115§F (62§C) during daylight hours, natural venting of heat was a factor in the overall design scheme.
The task of balancing energy efficiency and lamp longevity with good color-mixing and compact dimensions challenged the team to think "outside the box," and various theatrical effects lighting products such as multicolor LED systems, exterior dichroic changers, and gel scroller systems were carefully examined. "LAWA (Los Angeles World Airports) hired Paul Tzanetopoulos, a light artist, to direct the overall color programming, and he provided us with storyboards which were used to create the final lighting sequences," says Hollingsworth.
The vast difference in scale between the 6'- and 12'-diameter pylons led Hollingsworth and her team to decide on different systems for illuminating the two groups. "Paul was especially concerned about color-matching, particularly if one system was additive and the other subtractive."
Arranged in a circular pattern among a twisted labyrinth of roadways, a total of 15 columns bordering Sepulveda Boulevard rise 110' (34m) into the air. Each is equipped with 32 Martin Professional Exterior 600 exterior-rated color-changing luminaires mounted at four different elevations, eight to a level. According to Windle, "even with a 12'-diameter pylon, once we had factored in electrical equipment, clearances for panels and ladders, and OSHA requirements, we were still almost out of space." After the structural requirements were engineered and drawn, MRH translated the steel and glass into 3D using AutoCAD 2000 in order to verify fixture clearances. Simultaneously, a partial mockup of a column 25' in height was fabricated in Irvine, CA, for testing with various types of glass and lighting fixtures by the team.
"We had to design custom mounting brackets to attach the fixtures quickly and safely to available horizontal steel braces," remarks Windle. "The 3/8" steel brackets, also manufactured by Martin Professional, had to be approved by the structural engineers since each fixture weighs more than 100lb." Maintenance platforms were built at a comfortable level below each lighting position to allow easier access for service and relamping.
"We made some modifications to our standard fixtures," recalls Mark Pranzini of Martin Professional, technician and lead programmer on the project. "The city of Los Angeles asked us to further separate some of the power and data connectors, we revised the stock color wheel, added 24'-long [7.3m], hardwired power cables at each fixture, and combined DMX send and receive on one cable instead of two." A total of 480 fixtures were manufactured in Denmark and shipped to the site in under two months, according to Martin western sales manager Frank Montero. "It was all done in a big rush, and saying that we could do it on time was a very big commitment on our part."
"Carl Wake, our systems integrator, also came up with a clever idea for a frosting system to soften the hard edge of the beams, after the fixtures had been sent to Los Angeles," adds Montero. "They took the safety glass at the front of each fixture and spray-etched the center of the glass using a custom stencil and materials available from any local art supply store." Montero chuckles, then says, "just don't tell anyone. We may still want to patent the idea."
"Since the pylon lighting is all fed from street lighting power," explains Windle, "all of the equipment we specified needed to operate at 277V. To operate the controls, a step-up transformer was added in each column to provide 120V to the electronics." MRH also requested that power and control lines be routed in opposite corners of the structure to avoid the possibility of signal interference. Each individually isolated DMX line controls eight fixtures, and adjacent fixtures are addressed identically to cut the number of required channels in half. "Even with this measure," concludes Windle, "we still used over 2,000 channels of DMX control across a total of five universes." The firm Automated Lighting Services assisted the Martin team with the data wiring in each of the pylons.
For the 12 pylons that line Century Boulevard for nearly a mile and range in height from 25' to 60' (8-18m), MRH ultimately decided on Altman Outdoor PARs fitted with Wybron Mariner CXI color-mixing scrollers and 150W Philips CDM MasterColor lamps, all 368 units furnished by the LA-based Katie Group. "It would have been great to have added a support brace to mount the fixtures on," notes Windle, "but the structural design was already complete. Our AutoCAD 3D modeling demonstrated that the interior of the structure was much, much smaller than anyone ever could have guessed. As a result, we recommended a partial scale mockup of this structure be built as well, and that's when reality finally set in for everyone."
Space was such a huge problem that the smaller columns didn't even have the 30" of clearance required for a maintenance ladder, and a code waiver had to be made to allow the use of a single "utility pole-type" ladder at center. "The diameter of the steel structure was set in stone, literally," laughs Windle, "and the design was mandated by how much room was available on an 8'-wide roadway median."
"There simply wasn't enough room for a mosquito in there," agrees Tom Folsom of the Katie Group. "Fortunately, with Wybron's equipment," he adds, "we could set every scroller in a single column to the same address, and, as multiple units share a single power supply, we expect that long-term maintenance for the project will be much easier. In addition, we discovered that the two-scroll CXI design offers 30% more light output than other systems, and combined with the high lumen output of the metal-halide PAR fixtures, they were outrageously bright."
Since the metal-halide lamps could not be dimmed, a Mylar "blackout" frame was added by MRH to the gel scroll in order to fade out the fixtures on cue. A sixth universe of DMX provided three channels of control per pylon, two for the scrollers, and a third for a DMX relay driver card supplied by Orlando-based Candela Controls in waterproof, NEMA 4 enclosures. These enabled the design team to switch the fixtures, scroller power supply, and landscape lighting on and off using the remote master playback controller.
Even the paint finish on the fixtures proved a critical element, both at night and during daylight hours when the system is actually off. "The stock off-white finish created hot spots inside the column when illuminated by the fixtures below," explains Windle, "and when we experimented with black instead, they appeared to create dark patches which didn't reflect any light at all, and also look poor through the glass during the day. So, we compromised on a matte gray finish, not only on the fixtures and scrollers, but also on the structural steel and all interior components as well." The Martin fixtures in the taller pylons were also custom-painted on the rear panel with matte black in lieu of standard silver, to reduce reflected glare from the fixtures directly below.
The control system for the project consists of a network of four Pentium-based PCs, three of which generate a total of six universes of DMX and one which serves as an overall master controller. The computers run Martin's ProScenium software over ethernet using a fiber-optic distribution system that is routed throughout the site. "Given the amount of 277/480 conduit we had on-site, no one could guarantee us good separation between the signal and power runs, so we made the decision to go with fiber optics despite the higher initial cost," says Windle.
"The Martin system doesn't allow for multiplexing, so we couldn't daisy-chain from pylon to pylon," Windle says. "Each was an individual home run, with a few as long as 1,500' [457m]." At the base of each Sepulveda pylon, the DMX signals were converted to copper, optically isolated, and then distributed to the fixtures within. Along Century Boulevard, the fiber-optic line ended at Pylon 15, which is closest to Sepulveda, and was converted to copper for distribution to the other pylons along the median.
"We were a bit dubious about the control system at first," admits Hollingsworth, "but with all that fiber on-site and Martin terminating the connections out in the dust and open air, we didn't have a single control glitch. It was really amazing." Initial programming of the system was completed by Pranzini using a custom Martin Case console with twin processors from a location high atop the old LAX air traffic control tower overlooking the site. "We did it all in about one week," says Pranzini, "then dragged the board down to the basement to download more than 3,000 cues into the system."
Besides the pylons, MRH also provided landscape lighting for several oversized signage elements placed at the entry and exit of the airport, in addition to newly planted rows of palm trees on the approach roads. "The contractor ended up personally selecting the in-grade fixture used to light the trees because they were significantly easier to install than some of the other choices we presented," explains Windle. "And when you're scheduling labor, 300 hours of installation time can matter quite a bit," Hollingsworth adds.
Concludes Hollingsworth of the work at LAX, which opened in time for the Democratic National Convention in the city, "We usually find that the execution of the design is so much more time-consuming than the design itself." Windle adds, "We always put something in the drawings that shows our intent and then we try to be receptive to the electrical contractor's comments and opinions. That's the right way to do it." Hollingsworth, who created a workshop at LDI 2000 in October to discuss the use of construction details in design, ends by saying, "Unless you show what you want the end result to look like, you usually don't know what you'll get."