January 5, 2010 By Mike Jiggens
By Mike Jiggens
ARTIFICIALâ€ˆsports fields have come a long way since their introduction
nearly 50 years ago, but there is still no such thing as a
maintenance-free synthetic playing surface, more than 250 members of
the Sports Turf Association were told in September.
Redexim Charterhouse’s Chuck Hicks, speaking at the association’s 22nd
annual field day in Brantford, Ont., said the artificial playing field
is currently in its fourth generation of manufacturing type, and,
although it’s a vast improvement from its first generation days of
“Astroturf,” the fields still require regular attention if they are to
remain playable and realize a long lifespan.
“If anyone ever tells you that these things are maintenance-free, just walk away because he’s wasting your time,” Hicks said.
Although artificial fields don’t require mowing or the need for fertilizer, there are other maintenance practices necessary to keep them in tiptop shape.
“You need to keep your fibres in an upright position. What you do to keep your fibres upright is how you brush your fields. There’s some misconception out there that these types of fields are maintenance-free.”
It’s usually the installers of artificial fields who claim they’re maintenance-free and not the manufacturers.
Aside from the need to keep the turf blades standing upright, the surface must be kept clean at all times and the soil beneath must be periodically decompacted.
Hicks, who has more than 30 years of experience in managing both natural and artificial turf fields, suggested sports turf managers walk their fields at least every other day to make note of any debris or contaminants which might be present.
Because artificial fields can take significantly more play than their natural counterparts, they are apt to be introduced to several elements over the course of a day from round-the-clock play by field hockey, lacrosse, soccer and football teams. This often includes such human contaminants as blood, spit, sweat, vomit, dead skin cells and urine.
“All of these things are there on a daily basis,” Hicks said. “Weather will not eliminate these microorganisms (found in human contaminants) from artificial turf systems. It’s not like a natural field which has the ability to protect itself and to remove these organisms.”
Rain will not sanitize a synthetic turf surface.
“The only way rain is going to take away these microbes introduced into a synthetic system is if it’s raining Lysol disinfectant.”
Because bacteria can survive long periods of time on some surfaces, the disinfection of artificial turf surfaces on a weekly basis has become mandatory in some U.S. states, he said.
“We have to be aware of these things when we begin to embrace these types of surfaces,” Hicks said, adding microorganisms present can affect the functionality of the turf systems themselves.
Using such disinfectants as Lysol or bleach can keep the surfaces sanitary so that all users can safely enjoy them.
Sports turf managers also have to be watchful for natural debris which, left unchecked, can create other problems. For example, fallen maple keys can accumulate on a surface and eventually become mashed into the fabric and clog up the field’s drainage system.
Any type of grass field can contribute to a sports injury, whether it’s a sprained ankle or a concussion. Artificial fields tend not to become as compacted as natural fields, “but they do compact, make no mistake about it,” Hicks said, noting their G-Max rating needs to fit within certain parameters to ensure proper athlete safety.
A rating above 180 can facilitate serious head injuries while one below 20 can produce ankle injuries.
To help keep artificial fields decompacted, a tool such as a rubber-coated spring rake can be used on a monthly basis. A Clegg hammer device will determine the extent of a field’s compaction and whether or not it fits within safe parameters.
A field’s infill must be kept free of compaction, Hicks said. Depending on what infill material is used will determine how soon or how much a field will compact.
Aside from safety issues, compacted sand which infiltrates drainage holes will result in less water movement.
In late spring, snow may need to be removed from an artificial surface so that the field is ready for play on time.
“Use a rubber plow when snow is on the field,” Hicks said, adding it’s best to avoid snow removal if at all possible. If scheduling is an issue, however, a piece of PVC pipe can be attached beneath the plow blade so that snow can be pushed away with minimal risk to the synthetic turf blades. Any thin layer of snow which might remain afterward will soon melt.
If a municipality is considering the installation of an artificial field, the sports turf manager should learn from the field’s manufacturer to determine what type of maintenance equipment is necessary to brush through the surface, decompact the crumb rubber and sand mixture, and remove any unwanted pollutants.
Valuable information about artificial turf, site preparation and other pertinent data can be found at www.syntheticturfcouncil.org.
A synthetic turf field will typically cost between $700,000 and $1.5 million, depending on whether it’s just the field itself or the entire facility, including fencing, lighting, bleachers and other infrastructure.
The longevity of an artificial field is between eight and 15 years, according to most manufacturers. Much of its lifespan depends on how it is being used, how often it is used, how well it is maintained and whether or not athletes are using the proper footwear.
“For every synthetic field, you can replace six natural grass fields in the amount of hours they can be used,” Hicks said.
He added, however, they won’t replace other fields, and “everybody who maintains synthetic turf, typically up to 85 per cent of them are also maintaining natural turf.”
In the history of synthetic turf, there have been four generations in the way the product has been manufactured. The first—commonly known as Astroturf—was a nylon product often criticized for its abrasiveness. Perhaps its most famous installation was in the Houston Astrodome during the 1960s.
The second generation of artificial turf was introduced in the 1970s and was a polypropylene nylon product which was less abrasive and less expensive than its predecessor. It used a sand infill and featured the polypropylene fibres extruding from within a rubber matrix.
Commonly referred to as Sport Grass, the second generation of artificial turf fields was combined with natural grass which presented a problem.
“Combining two systems created something that was going to allow us to have better fields and a lot more usage hours on each field. The existing issue with it was that the rubber barrier tended to block the root zone movement.”
Once installed, it was an impressive-looking field for about four months, but then it would succumb to summer decline. Hicks said field managers would be forced to use a deep tine aerifier to poke holes through the rubber matting to allow the natural grass roots a chance to extend through further.
The third generation, which he calls a carpet “because that’s the way they’re made,” is different from the previous generations in the way its backing is manufactured.
The manufacturing companies weave the fibres into the mat in a distinct way. The size of the holes in the mat’s backing are more conducive to drainage, and the means in which the mats are sewn together tend to create passage channels for better water movement.
“In this third generation, you’ll see that the fibres are actually spaced quite a bit apart. There’s a lot of distance from the first generation Astroturf.”
There is now a mixture which goes into the carpet itself, Hicks said. Manufacturers today will use a silica sand and crumb rubber, and some will say it has to be cryogenically treated. Studies are ongoing with all manufacturers, “and they’re creating a better system all the time.”
Hicks said he recently returned from a trip to Europe where a moratorium has been placed on crumb rubber.
“That’s partially because they’ve found out through scientific study that the crumb rubber does off gas, and the gases it releases are carcinogenic.”
Nonetheless, the amount of rubber-released toxins are so minute that a three-year-old would have to spend about 13 years sniffing the surface at ground level before there would be a problem, Hicks said.
In Europe, the crumb rubber is being replaced by a type of rubber-coated sand which is inert and sterile.
“So now we’ve got something to replace those blades of grass that’s never going to off gas or harm our environment.”
Hicks said a couple of artificial fields were shut down in New Jersey in recent years due to lead issues associated with the second generation of fields. With newer third and fourth generation fields, the danger of lead chromate leeching into the soil is no longer a problem.
There are now more than 50 companies in North America which are manufacturing artificial turf based on a similar premise yet with slight variations on the same theme, he said.
“This stuff is here to stay now. I don’t think we’re going to see these generations where they came in and replaced our existing fields and then went back.”
During the era of second generation artificial turf, users would realize they couldn’t enjoy the same game quality as they could with natural fields, and fields were often converted back to their natural state.
With the new generation of artificial turf, the sand holds the carpet in place and gives it weight to prevent wind from getting under it and blowing it about.
If a municipality chooses to have an artificial turf field installed, it is important for the sports turf manager to be directly involved every step of the way, Hicks said.
“If you hire a company to install your synthetic turf field, do not remove yourself from the process. Be sure you’re involved in every single step. If you don’t know how to install a drainage field, find one of your peers and learn these things.”
When dealing with the choker stone layer, often there are no clear specifications, and the installer is left to his own devices. He may end up purchasing gravel from a local pit which normally supplies material for road bases.
“When he comes in and puts it in your field and rolls it out and compacts it down before they go to the next layer, that’s going to be a problem for you because then if Mother Nature gives you a couple of inches of rain through the week, you end up with four inches. Now you’ve got a problem, and you’re wondering why your field is saturated. It could be in the base of construction.”
Involve yourself in the process and ensure nothing is done without your approval, Hicks said.
Monofilament fibres have become the new standard in artificial turf surfacing. Introduced during the third generation of field construction, today’s fourth generation fibres are a polyethylene which maintains its intended characteristics. Variations in colour give the turf blades a more natural look, incorporating both dark and light green shades as well as bits of tan.
The monofilament fibres also work better because they spring back after play.
“All of these turf systems are made to play on the top of the turf.”
Older-style web fibres had a tendency to lay over and, if fields weren’t brushed periodically, they gave an unnatural-looking shiny appearance.
Only a handful of companies actually manufacture the filament used in their product, but more are getting into producing their own backings with recent advancements in science.
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