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Movable Turf Systems Becoming Popular Option for Venues

With sales of new infill systems flying high and interest in modular grass and synthetic fields growing, turf is really on the move.

In a world featuring notoriously chaotic systems such as weather patterns and the stock market, the future of sports turf is quickly becoming among the most difficult to predict.

Think back to five years ago. Synthetic turf was dead, the pundits said. Dick Allen's famous comment - "If a horse won't eat it, I won't play on it" - was now the opinion of 95 percent of professional athletes, and college and major-league football and baseball teams were ripping out their rugs as a come-on to prospective student-athletes and free-agent professionals. One major venue - Giants Stadium - decided to become the guinea pig in a grand experiment to cover the synthetic turf there with a movable, palletized grass field that was going to revolutionize the way fields are conceived and built in the United States.

Then, a funny thing happened. Wait - make that two funny things. First, a Montreal-based company took a discarded technology that a decade before had failed to take root, made an important alteration and turned its product into a global synonym for the state of the art. Then, a handful of professional grass fields, several of them utilizing either palletized or high-tech hybrid technology, suffered repeated failures on national television. Synthetic turf was reborn.

And, unexpectedly enough, so is the movable movement. One year removed from modular turf's most spectacular failure - again, Giants Stadium - movable turf systems employing even more innovative technology are being contemplated by at least two professional teams.

There is just no way, it would seem, to keep up with the fast-moving synthetic turf market.

In the mid-1980s, while Balsam Corp. (now SRI Sports, the maker of AstroTurf) was buying up turf and grass companies to dominate the sports-field category, an innovation in synthetic turf promised to shake up the industry. Instead of the knitted nylon carpet that had characterized AstroTurf since its invention in the 1960s, this product (touted by Omniturf and several other companies) was a blend of tufted polypropylene fibers woven into a carpet backing, giving it a more grass-like look. To counter athletes' primary complaint about synthetic turf - that its subbase (a foam pad laid directly on concrete) was harming their joints and thereby shortening their careers - these products used sand as an infill to create what was supposed to be a more shock-absorbent surface. In addition, the sandy subbase would allow the turf to drain more like a grass field, nearly eliminating the 30-inch crown that was necessary to allow water to run off a synthetic turf field.

However, tufted infills' time had not yet come. "The science just wasn't advanced to the point it is now," says Ray Rudolph, who heads up the sports division for Albany, N.Y.-based architecture firm Clough Harbour & Associates LLP. "The infill used was well-graded sand that compacted extremely densely. Omniturf installed about a hundred in the mid- to late '80s, then Balsam bought them out and they went by the wayside."

One company with tufted-turf experience, however, continued to tweak the formula. In 1988, Jean Prevost, a former tennis pro whose SynTenniCo installed synthetic-surfaced tennis courts throughout the 1980s, bought the patent for a tufted material and joined with John Gilman (a former Canadian Football League player) to hatch FieldTurf in the early 1990s. FieldTurf spent seven long years struggling to gain traction in the turf industry, but eventually reached national prominence by landing a few choice jobs, picking up enthusiastic endorsements and marketing itself like crazy. In one of those sudden breakthroughs that give capitalism a good name, "FieldTurf" began to be used generically to describe the entire tufted-infill market, much the way "AstroTurf" was used for the previous quarter of a century.

SRI, which still enjoys a hefty market share, spent several years dismissing tufted-infill technology as dated, fragile and even dangerous. Soon, though, the company jumped on the bandwagon (with AstroPlay), as did a number of field designers who up until then were content to sit on the sidelines and wait to see whether or not tufted infills would take off. The result has been a rush of extremely fractious competition; there are now more than 40 - some say significantly more than 40 - major suppliers and importers (from Europe) of tufted-infill turf. As the competition has intensified, the price has come down, putting tufted infills within the reach of pro teams, colleges and even high schools.

Why the sudden rise of tufted infills? Tinkering and timing. FieldTurf is credited with spending a lot of time on research, refining the grass-blade material so that it could withstand more abuse and making a number of other minor improvements. Infill turf's big breakthrough, though, came with the replacement of much of the sand in its system with recycled rubber, which in the '90s also gained prominence as a component of many different types of sports surfaces.

Turf manufacturers - none were interviewed for this article, for reasons that should be apparent - market their tufted-infill systems as having unique qualities, but most field designers will tell you privately that the similarities between tufted infills far outnumber their differences. Indeed, like knitted-nylon systems, all North American tufted turf is produced in Dalton, Ga. ("the carpet capital of the world"), and a number of products currently available are essentially identical. Says Scott Clark of Clark Companies, an installer of grass and turf fields in Delhi, N.Y., "This technology is 30 years old. We bought tufted turf 20 years ago for golf tees - same stuff. Anybody in Dalton, Ga., with a Skilsaw and a pickup truck can be a turf contractor now. That's a fact."

It should be noted that tufted turf systems - as a class of synthetic surface, regardless of manufacturer - are so far ahead of the old knitted nylon systems in terms of playability and comfort that there are few naysayers among end users. On the other hand, these systems' proliferation is new enough that no one knows for sure whether tufted turf will survive the seven- to eight-year warranties under which most are sold. The polypropylene fibers aren't as strong as nylon, leading some field designers to warn against using plows to clear snow off them. Worries of UV degradation, meanwhile, appear to be no greater than with any other kind of synthetic surface. "By all accounts it has held up," says Rudolph of FieldTurf's oldest installation, a Pennsylvania high school football field that has been closely watched by industry pros. "There has been wear and tear; it's only supposed to last eight years, and it's still playable after six."

Dan Almond of Millenium Sports Technologies, a Littleton, Colo.-based field installer, estimates the infills will last for eight to 10 years. "It's an evolving technology that has definitely improved from five years ago," he says. "The bigger turf companies have really perfected their systems; there's some good stuff out there."

Industry insiders hope some light will be shed by the first study to observe the effects of weather and wear on tufted infill systems. The eight-year comparative analysis of 12 turf systems was begun in the summer of 2002 by Andy McNitt, assistant professor of soil science and turfgrass at Pennsylvania State University, who will release the initial findings this coming winter. Hardness, abrasion and traction will be gauged regularly to see what happens to the systems over time; McNitt hopes the study will allow him to make recommendations for installation and grooming. (See "Shock Value," Sept. 2002, p. 54.)

McNitt's focus isn't completely on the warranty. "One area that nobody has addressed is the potential for bacterial growth," he says. "I don't know if it's real, but think about the way stadium managers disinfect traditional synthetic turf with detergent and vigorous brushing, something you can't do with an infill system. We have no evidence of a problem, but I am envisioning the potential for one. What if someone throws up on it during practice." (The standard procedure is to vacuum up the soiled infill and replace it, and turf-cleaning solutions are available.)

You can count Clark among those who question whether tufted infills will stand the test of time. In fact, Clark is betting on knitted-infill systems - he admits to being wowed by NexTurf, an SRI product - to outperform tufted systems. Knitted-infill systems, he says, offer the "proven durability" of the old AstroTurf 12 (so called because of its 12-year wear guarantee) and the playability and comfort of infill systems. "Conventional infills, including AstroPlay, are very soft and have a wide fiber - they're a lot better than AstroTurf used to be, but they don't really feel like real grass," Clark says. "Knitted infills cost significantly more money, but they're going to last 12 years, and feel and play great."

Clark would seem an unlikely champion of infill turf, as his name is closely associated with the Giants Stadium "fiasco" (as the newspapers have called it for the past two years) and, moreover, he remains a believer in the possibilities of movable grass fields.

Clark was involved in the first such application, the movable field that turned the Pontiac Silverdome into a World Cup soccer venue in 1994. That field was laid out on heavy steel trays and passed its test with flying colors. Such was the system's (and Clark's) reputation that his company was called in to supervise the installation of a movable field in Atlanta four days before the 1996 Olympics, after the existing field was destroyed by 18,000 dancers practicing for the opening ceremonies.

Meadowlands officials came calling in 1997, hiring Clark Companies to install a movable grass system (this one on lighter polycarbonate trays, manufactured by GreenTech) over the venue's AstroTurf. A six-week experiment in 1998 (three football games, two concerts and four soccer games) went well in spite of some damage from the opening concert, and players who had long hated synthetic turf were thrilled. ("I'd rather play on dirt than artificial turf," declared Giants cornerback Jason Sehorn.)

A second experimental installation took place in 1999, this time with the addition, in one section of grass trays, of synthetic fibers to help give the field added strength. In 2000, the full field was installed for the Giants' and Jets' NFL seasons. Reiterated Sehorn early in the 2000 season, "I'll play on mud in December rather than turf."

The Giants didn't play on mud that December, but portions of the field had to be replaced on five different occasions. By late 2001, the teams often were playing on mud, and in a cruel bit of irony Sehorn was knocked out of the Giants' playoff run after spraining his ankle on the wet field. In October 2002, after more poor reviews ("The worst grass field I've ever played on," said running back Ron Dayne), the trays were removed and 60,000 square feet of sod were laid over the synthetic surface. The experiment was over.

Clark has clearly suffered some slings and arrows, but he sees a future for movable turf systems - at least in a limited fashion.

To begin with, he believes (as do many in the turf business) that the Giants Stadium project was probably doomed to failure by the New Jersey Sports and Exposition Authority's decision to host not only the two NFL teams, but also the XFL (immediately following the NFL season, in February), college and high school football games, professional soccer and many concerts. In fact, if there was one primary lesson learned throughout the four-year experiment, it's that, like any grass field, there's a limit to modular turf's ability to bounce back from heavy use.

Tom Gabbard, associate athletic director for internal affairs at Virginia Tech, which became the first college to install a modular field in 2002 (another Clark Companies-GreenTech collaboration), says he and his grounds crew were very familiar with the Giants Stadium situation even during the selection process. "We went there to look at it, and what we found out was that they had two fields and were moving them in and out, in and out," says Gabbard. "We have seven games plus graduation that we hold on our field, eight events in all, and they were probably holding 80 events a year. No grass is going to hold up when that happens."

Virginia Tech went modular because the school was in the midst of a phased renovation of Lane Stadium, and the thought was that part of the field could be removed to allow cranes to be set up where that portion of the field had been. As it turned out, the expansion of the south end zone took place with the cranes set up outside the stadium, so none of the trays has been moved. The school keeps 40 extra trays growing outside in case a problem occurs with any of the grass, and it may turn to these when and if the stadium is used to host a major concert.

Giants Stadium's field consisted of 6,000 octagonal trays, another drawback to the system as conceived for such a high-use venue. "There never was going to be a widespread use of trays," Clark concedes. "It's such an expensive technology that you really have to have a driving need to do it. But I think there will always be modular components of fields - for example, baseball fields with a convertible infield so you can play soccer on the field. Our next step was going to be movable turf just on high-use areas, such as between the hash marks or between the 40-yard lines." Virginia Tech's situation, he adds, points out another use for modular turf: fast-tracking a stadium construction. "You can build the field off-site, and have cranes sitting where the field would have been until a week before the first game, then move your field in, even if it's not going to move after that," Clark says.

Virginia Tech (and now Michigan State University, which installed modular turf last year) had one more stated reason for choosing a modular system: placing grass on trays leaves room for warm air to be circulated underneath, thereby keeping the root zone stimulated and the grass growing throughout the year. "The weather here is tough on Bermudagrass, which is what we're trying to grow," says Gabbard. "We've installed a heat system, a vacuum and a blower system, so we feel like we've got the winter whipped - although we'll know more by next winter."

To a certain extent, Tech's decision was ultimately shaped by the desires of its head coach, Frank Beamer, who insisted on grass. That left infills out, at least for now. "We knew Nebraska felt pretty confident with their FieldTurf system, but they were one or two years into it, and our experience had been that if there are going to be problems they're going to crop up after three or four years," Gabbard says. "We didn't want to be pioneers in the infill system - and then we turned out to be pioneers in the tray system."

Modular turf continues to be pitched as the perfect solution in enclosed stadiums - play a game, move the turf out to the parking lot where it can soak up some rays, then move it back in for the next game. In practice, though, moving hundreds or thousands of trays takes time, meaning that the grass ends up spending a lot of time below street level in the shade - and worse, in domed stadiums, air-conditioned shade. The continual separation of trays doesn't allow the grass to grow together and, as occurred in the Meadowlands, can lead to damaged trays that don't fit quite right. Add to this the scarcity of land around stadiums to keep a second 96,000-square-foot field at the ready, and you've got the potential for an operational nightmare.

That's the way Cyril Silberman sees it, anyway. Silberman is president of Uni-Systems LLC in Minneapolis, a firm that has developed mechanized roofs and sliding walls for a number of recent stadiums including Bank One Ballpark, Minute Maid Field, Miller Park and Reliant Stadium. Working on the latter project, Silberman says he was struck by that stadium's difficulties with its modular turf system.

"They're really struggling with it," he says. "There's just not enough light to keep the grass growing. But more than that, they just can't do a quick change-out of the turf with regular people, people who aren't super engineers. It has taken them a couple of weeks to do a switch-out with the very best help they can get."

For a man who develops stadium roofs that can open and close in minutes at the touch of a button, the solution seemed obvious: Place the entire field on rollers and move it out of the stadium in one piece. Uni-Systems got working on the problem, patented its (still-in-development) system, and will install it in the Arizona Cardinals' new stadium, which is scheduled to open in 2006.

Obvious? Perhaps. But not simple. Some of the requirements include:

• A thin pan on which the 3-foot-thick field section will be laid. "The problem," Silberman says, "is building something that thin that vibrates with the right frequency." Huh? Silberman explains: "It has to have a natural frequency of 7 hertz or greater when football players are running around on it, otherwise it'll start to oscillate."

• Wheels on which to set the pan. These could be air or water bearings, Silberman says. "We think the most economical solution is many wheels about every 20 feet. These will be tuned to the beams that go across the top of them, and the entire mass then tuned to the correct frequency. It just sits there until you push the button."

• A drainage system. Uni-Systems is still trying to decide on the exact configuration, and Silberman says the system chosen will determine whether the completed pan of turf weighs 9 million or closer to 14 million pounds.

• A smooth concrete floor - the surface for trade shows to tractor pulls - with troweled-in embedded rails located every 20 feet. The central rail will include a recess to keep the field on track.

• A clear-spanning header across one end of the stadium bowl so the field can slide in and out. Bleacher sections along that end must be mechanized so they can be raised slightly to allow the field to pass underneath. The route outside will resemble a mail slot, albeit one that is 7 feet tall.

The total cost of such a system? About $2 million for the mechanized aspects, says Silberman. "It won't make the grass grow better, but it will work for natural or synthetic turf, and we can guarantee you can do back-to-back turnarounds in 60 minutes."

Andy McNitt thinks this is - well, for lack of a better word, nuts.

"It's gotten so crazy that my stock joke is, 'Why don't they just hire a whole bunch of helicopters and pick the stadium up and move it?' " McNitt says. "That way you don't have to keep moving the grass around."

Silberman, though, says the demand for truly multipurpose venues is what is driving these sorts of technological discussions. (It's also the reason for the development of modular infill systems such as Hummer's Sofsport.) In fact, Silberman reports that he's getting much more interest in the rollaway system from people wanting to put in synthetic turf than those seeking natural grass.

"There are some real advantages to having synthetic turf," he says. "If you're in a football playoff situation and you're going to have four games in a row, what kind of grass field is going to take that? Grass gets in the way of having other events; you can't have an auto show or tractor pull on top of it."

Additionally, synthetic turf would solve the real-estate problem associated with rollaway fields: Just construct a slot outside your parking garage, for example, and roll the field underneath. There are other applications, too; Silberman has had discussions with a municipal parks department about a potential rollaway recreational field that as of now frequently sits underwater because it is within a major river's floodplain.

"The Cardinals project went up to the voters three times and was rejected, the main reason being that even with the most creative accounting you couldn't prove you could pay the bonds off with nine NFL games," says Silberman. "Once we were able to suggest it could be a multipurpose stadium and host 100 events a year, then the numbers all lined up. The enabling technology is the movable field."

Ultimately, the sports played, and how often they're played, will determine whether the highest-tech fields take hold. Baseball, with its three outfielders patrolling three acres, will always be dominated by grass. Field hockey, where ball roll is vital, is a perfect fit for plain old nylon carpet. Soccer may be an anomaly, a sport that has shown itself willing to adapt to whatever surface is currently the rage. (FIFA's 2002 decision to recognize tufted infills, though unexpected, demonstrated organized soccer's understanding that more young players are learning to play on synthetic surfaces.)

For multipurpose uses, nylon is showing that in addition to standing up to high use on the field, it's able to take even the toughest verbal abuse heaped on it by proponents of tufted turf. "We like nylon for student recreation; it's just an incredibly durable surface," says Rudolph. "The prototypical design of a piece of nylon inside a running track is still fairly popular in high schools, smaller colleges - anyplace where you have a lot of people who want to play a lot of sports." If there's one drawback to the rise of tufted infill systems, Rudolph says, it's that there are fewer manufacturers around who can offer competitive bids on nylon surfaces.

And what of plain old grass? Athletes still say they prefer it, notes Millenium Sports Technologies' Almond, even with all the technological improvements to synthetics over the past five years. But pragmatism will trump preference soon enough, predicts Rudolph.

"From a strictly playability standpoint, playing on a synthetic infill system is probably not as good as a good natural grass field," he says. "But there are just so few good natural grass fields that the infills are going to rise to the top."

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