lluminating Technologies, Techniques for Controlling Wayward Light
Call it a power shortage of sorts in the Pacific Northwest. Each year, the parks and recreation department in King County, Wash., turns away hundreds of recreational sports teams in search of a place to play simply because it runs out of fields it can turn on — namely, those equipped with lights.
"These fields run every night until midnight," says Del Armstrong, whose Bellevue-based company, Soft Lighting Systems, manufactures the fixtures used to flood dozens of fields in the Seattle area with light. "It's amazing. We take people out there to show off our system, and here are two teams finishing up and two more teams warming up — at 10 or 11 o'clock at night. This is crazy, right?"
Without question, people across the country and from all walks of life are crazy about their own organized sports participation, and these days the average weekend warrior wages a good share of his or her battles on weeknights. As a result, lighted fields dedicated to amateur sports activities such as slow-pitch softball are believed to comprise as much as 80 percent of all sports field lighting in the United States. "The big part of the market is the Little League fields, the high school football fields and the recreational softball fields," says Joe Crookham, president of Musco Sports Lighting in Oskaloosa, Iowa, "because there are thousands of those compared to dozens of the big ones."
Despite that disparity, the lone characteristic that separates the big ones — professional stadiums — from suburban softball complexes and the like is the amount of light poured onto their fields, and that difference is dictated to a large extent by television broadcast requirements. The hardware and wiring used to produce artificial light vary little from one level of competition to the next.
That is not to say that sports field lighting equipment hasn't evolved greatly over time. Indeed, much has changed in the technology and techniques involved in the sports illumination process since its debut in 1883, when General Electric strung a handful of open-face lights across a minor-league field and night baseball was born. Today, the 500 to 900 fixtures typically pointed at professional fields produce a playing environment 400 times as bright, according to Mike Owens, general product manager for sports lighting and roadway products at GE Lighting Systems in Hendersonville, N.C.
That brightness, while enhancing visibility for players and fans, becomes bothersome when it trespasses onto private property or escapes into the night sky. Even recreational fields, despite their dimness relative to professional venues, must address glare and trespass concerns due to their proximity, in many cases, to residential neighborhoods. "That's the key today: How do I make sure I can have a ball field without disturbing anybody." Owens says. "It's a major concern, and manufacturers today offer special systems and accessories to limit the amount of light going off the facility."
Before considering methods in which sports field lighting is controlled, it helps to know at least the basics of how it's created. To accommodate games at night, facilities must simulate as best they can natural daylight. This is done by grouping light fixtures atop poles, press boxes and stadium seating decks — anyplace high enough to angle beams of artificial light downward onto a field.
The individual lamps used to illuminate sports fields range in capacity from 1,000 to 2,000 watts. The lower the wattage, the longer the lamp life, but a greater number of lower-watt lamps will be necessary to produce a desired light level on the field. Most sports lighting experts recommend use of a 1,500-watt metal halide lamp, extolling its availability from a variety of suppliers and easy replacement. Other lamps, such as a 1,650-watt variety or what's called a 1,500 long-life lamp (which is engineered to provide 6,000 hours of use vs. the standard 1,500-watt lamp's 3,000 hours), are considered specialty products and are not widely available. The 2,000-watt lamp, another specialty option, differs from the others in that it is double-ended, attaching to the fixture in two locations as opposed to being screwed into a single socket. This lamp lights instantly once full power is restored following a temporary dip or outage, whereas the others require up to 15 minutes to cool before restarting, making the 2,000-watt lamp increasingly popular in sports venues that accommodate TV broadcasts.
The most common type of sports lighting fixture used to house each individual lamp takes the shape of a spun parabolic, meaning it appears circular when viewed straight on and like half an egg when viewed sideways. Mirror-like reflectors lining the fixture also assume this parabolic form, allowing light emitted from the lamp to be gathered and redirected in a single beam outward through the fixture's circular lens — the whole system functioning like a large version of a household flashlight. However, unlike most flashlights, the sports fixture can be adjusted to create beam spreads by moving the lamp socket in or out from a mathematically calculated focal point within the spun parabolic reflector.
Each fixture's beam spread — which can also be influenced through the use of an alternative, frosted-surface reflector that diffuses light — is dictated by the distance the beam must travel to a specific area on the playing surface and what it needs to look like when it gets there. The farther the distance, the narrower the beam. Hot spots on the field created by narrowly focused beams thrown short distances should always be avoided, according to George Brammer, inside sales and product manager for sports lighting at Hubbell Lighting in Christiansburg, Va. "The key to design is choosing the right beam spreads for the proper aiming distances so that you get a uniform field," Brammer says. "When your eye passes across it, you want to see just a wash of light."
The process of aiming fixtures can take place on site or before the fixture assembly leaves the manufacturing facility. Field aiming entails creating a grid on the playing surface with strings or flags and targeting each point on the grid with light fixtures, which may even come equipped with aiming sites similar to those on a rifle. Light levels are measured and radioed up to the mounting apparatus, where workers lock each fixture into place one-by-one. It's a process that may take three days at a professional venue, even with skilled and experienced crews doing the work.
Factory aiming, meanwhile, was developed as a means to take the on-site guesswork of inexperienced contractors out of the aiming equation. It involves creating a computerized model with inputted dimensions of the actual playing field. Once the model is checked for accuracy against the real thing and optimum light-mounting heights are factored in, trained factory technicians aim and anchor each fixture on cross arms in relation to where its beam should meet the field and, equally important, to where other fixtures' beams are directed.
"The analogy I sometimes use is a tile floor," says Crookham. "If you were laying out a tile floor on the football field or a baseball field, whether or not that tile floor slid a few feet one way or another wouldn't be a big deal. Whether or not the individual tiles lapped up on top of each other would be a big deal, because you'd have bumps and gaps along the tile floor. What we can do by factory aiming is to ensure that all of the tiles fit very tightly next to each other, and all you have to do now is get the whole tile floor roughly lined up."
Once on site, one variable that can throw a field's pre-aimed lighting out of alignment is the off-axis installation of one or more poles. But, Crookham adds, "there's nothing about factory aiming that keeps anybody from making adjustments when out in the field."
The half dozen or more poles that surround a given field (depending on the sport and competition level) are usually made of galvanized steel, but concrete poles are still found in coastal areas where corrosion is a concern. One manufacturer has even introduced fiberglass to sports lighting poles. These days, wood poles appear only on recreational fields, where tight budgets may be an issue. In fact, local utilities often donate wood poles toward a field's new lighting installation. Wood poles can warp, however, skewing the direction in which their light fixtures are aimed, with the potential to adversely affect light levels on the playing field.
Power is supplied to the light fixtures through wiring that runs the length of the hollow center of steel and concrete poles, and along the exterior of wood poles. Ballasts, located either on top of the pole with the fixtures (integral ballast) or at the pole's base (remote ballast), regulate the amount of current reaching the lamps. While remote ballasts are more accessible for maintenance purposes, not all sports lighting experts heartily endorse their use, reasoning that additional wiring and connections only complicate installation, and of all the lighting system's electrical components, the ballast is the least likely to require maintenance anyway. By far the weakest link in the lighting chain is the lamp itself, which may require replacement every two years or so.
To that end, one manufacturer has succeeded in making even hard-to-reach lamps more accessible. A type of pole introduced within the past five years to sports fields comes from GE's roadway lighting division and allows maintenance personnel to lower the entire fixture assembly to ground level with a motorized cable winch located inside the pole. "You can actually have the lamps and fixtures come down to you, change the lamps, clean the fixtures, wait until a hurricane goes by and then put them back up again," says Tony Burns, manager of marketing programs for GE Lighting Systems.
Another manufacturer has patented a system that allows users to troubleshoot the entire sports lighting circuit from ground level. The five-point diagnostic examines everything from lamps to fuses, and is accomplished by plugging a device about the size of a lunchbox into each pole and pressing a single button. Maintenance needs are indicated through a small panel of lights. "You don't need to be an electrician to operate the system," says Rick Kohl, vice president of marketing and sales for Qualite Sports Lighting in Hillsdale, Mich. "It allows anybody, any troubleshooter, to analyze and map out problem areas prior to hiring a lighting maintenance company or a lift."
Once the components are in place and capable of producing adequate amounts of light on a playing field, what can be done to keep light from streaming far outside the lines?
Light escapes the confines of a sports facility in three forms: glare, trespass and sky glow. Glare refers to light that is actually hard on the eyes. It can result from an overabundance of light bathing a playing field or by fixtures aimed in such a manner that looking at them causes discomfort. Trespass involves light intended for a sports facility entering an area in which it doesn't belong — a neighboring home's living room, for example. Sky glow is light thrown upward, obscuring one's ability to see stars in the night sky. All three represent wasted light.
A basic means of limiting wasted light — and energy consumption — is to more closely monitor when lighting systems are turned on and off. Consider the softball umpire who holds the key to controlling a field's lights. Faced with presiding over three or four consecutive games on that diamond, the umpire may choose for the sake of convenience to fire up the lights before the start of the first game, even though the sun may not set for another two hours. Musco is currently in the beta-test phase of an Internet-based system that will turn lights on and off automatically for customers across the country at predetermined times, record who is using the field and track the field's lighting maintenance needs.
But because lights in most sports facilities must remain on for hours at a time, many of today's sports lighting fixtures are designed to limit wasted light and energy, as well, allowing facilities to install fewer fixtures to adequately illuminate a field. "We're doing today with two 1,500-watt lights what 25 years ago would have taken us three 1,500-watt lights to do," Crookham says.
Some fixtures include internal louvers located within the top half of the unit between its reflector and lens. Typically numbering three to a fixture, these louvers in a way resemble venetian blinds but are permanently positioned to redirect light headed upward from the fixture back into the main beam and down to the field below. Faceted reflectors are also used to limit unwanted diffusion and concentrate more light onto the field, as are units whose lamps are mounted horizontally in front of and closer to the reflector, as opposed to axial mounts, in which lamps protrude straight out from a rear socket. Qualite fixtures angle lamps upward 45 degrees from axis, directing light gathered by the top half of the reflector downward, "not across the field into players' eyes or into the stands," Kohl says. Finally, external visors, which resemble the bill of a cap, are used by a variety of manufacturers to block skyward light and dampen glare, particularly glare emitted from fixtures that happen to be situated in close proximity to a neighboring home. Says Kohl, "Visoring captures the light and keeps it within the facility, reducing the amount of spill that goes out to the neighborhood and solving the problem in areas where everybody wants the facilities, but they don't want them in their backyards."
One manufacturer has opted to address control issues in sports field lighting by abandoning traditional notions of louvers, visors and tilted sports lighting fixtures. Instead, Soft Lighting Systems offers a fixture shaped like a shoebox and mounted with its lens pointed straight down. But instead of creating a collective hot spot at the foot of the pole, these fixtures use angular reflectors to gather light and throw it forward onto the field at roughly a 55- or 60degree angle. No light is emitted above the plane of the fixture. Meanwhile, light reflected off the playing surface sufficiently illuminates the underside of footballs, soccer balls, baseballs and softballs, providing players ample visibility while eliminating glare, according to Armstrong, who has overseen the installation of the system at facilities in Washington, California and Nevada.
"This system doesn't work in a Major League stadium; it only works for recreational fields, because the fixtures have to be close to the field. It'll get light behind second base, but you have to have the pole right at the fence," says Armstrong, a member of the committee charged with updating the Illuminating Engineering Society of North America's 100-plus-page manual on recommended practices for sports lighting, due out later this year.
"We're not going to put the spun parabolic out of business," he adds. "You're still going to have to have those for any large facility where there are grandstands or other reasons that poles have to be set way back."
Based on the stadium construction boom of the past several years and on the increasing number of illuminated recreational sports fields dotting America's nighttime landscape, there appears to be plenty of lighting business to go around these days. At the high end of competition, lighted fields have allowed a burgeoning number of TV networks and 24-hour sports channels to turn prime time into game time. "In 1982, only a third of the college stadiums in the United States had any lights at all, and most of those were not adequate," Crookham says. "Today, two thirds of the stadiums in the country have lights, and most of them would be adequate for television."
And facilities that make up the remaining third don't need to be left in the dark, either. Crookham's company contracts out temporary lighting solutions in the form of large trucks with lights clustered on top of cranes. "They're really rolling laboratories," he says. "We're able to devise and develop all sorts of experimentation on how you can light sports fields. We can tilt and focus each individual fixture from the ground with a remote control device. If we don't like the aiming logic, we just change them all around. If we don't like the pole location, we'll pull the outriggers and move the truck a little bit."
In light of these advancements, will artificial light aimed at sports fields ever truly rival the sun in terms of impact on game playability? "No. It will never be as good," admits GE's Owens. "But in some cases, it's better. If you look up into the sun, of course, you're blinded. You can still look at most fixtures and not be blinded."
Today's facility planners and managers are confronted with a truly dazzling array of sports field lighting options, as manufacturers respond to concerns about glare, trespass, sky glow and energy efficiency. Their products may never completely replicate daytime playing conditions, but they nonetheless make participation possible for a busy population of sports enthusiasts whose free time rises only as the sun sets. "That's when the people play," says Armstrong. "They don't play in the middle of the day. They play at night, so you have to have lighting."
Facility of the Week
The Salvation Army Ray and Joan Kroc Corps Community Center (Quincy, IL)