Once you decide you want synthetic turf, that is day one in in a process that you hope will lead to a phenomenal playing surface. It is a big investment and you deserve the very best synthetic field, but also the very best constructed foundation to support it.
Technology in synthetic turf changes rapidly. Turf systems today are based on shorter length fibers and much greater density so athletes actually play on the synthetic turf instead of only playing on the turf infill between the fibers. You’ll hear terms such as monofilament, slit film, blended fiber, rootzone, infill and force reduction. For those who want to know just a bit more before making a call, here is a little Synthetic Turf 101 to help get you up to speed:
Warranty: Lots of companies make promises on warranties, but a warranty is only as good as the integrity of the company offering it. The industry standard in synthetic field construction is 8 years, insured through a third party. Some advanced synthetic systems offer 10-year warranties and some pads for underneath synthetic systems offer 16-year warranties.
Do not accept a product that uses a prorated warranty. If your field doesn’t make it through its 8 years, you need a new field, not a check for 1/8 of a new field. Also, read the exclusions and the requirements on your part to not void the warranty. The more hoops you have to jump through, the more difficult it will be to enforce a warranty. Check to see if the warranty guarantees the field to remain below a specific force reduction value. American Society for Testing and Materials (ASTM) sets a maximum Gmax rating of 200, above which “qualifies for the expectation that life threatening head injuries may occur.” We’re not comfortable with your young athletes playing on that and you shouldn’t be either. Our industry partners, the Synthetic Turf Council and the NFL, have adopted a much lower maximum Gmax rating of 165. AstroTurf even has products with a 10-year warranty that have demonstrated Gmax ratings below 110. Our young athletes deserve the safest fields possible and the warranty should ensure it will stay that way for the life of the field.
Durability: Fibers in synthetic fields should be durable. There are options for blended fiber technologies that leverage the natural grass look of monofilaments with the durability of slit film fibers.
Prefab: Many of the synthetic field systems can be prefabbed. That means the lines and numbers can be cut into the field within the climate controlled confines of a giant warehouse instead of trying to perform these operations in the blazing sun onsite at a stadium.
Fiber density: Also referred to as the “Face Weight,” this refers to the weight of fibers in a square yard. Many products on the marketplace are in the 36 oz. range, though some products are available in the 60 oz. and even 80 oz. range. Fiber should do more than mimic the look of grass. Today’s artificial grass fibers go beyond looking pretty to be durable and actually create the playing surface. Fibers can be tufted 3/16 to 3/8 inch apart though some infill systems are ¾-inch apart. It goes without saying that the more fiber is present in a synthetic system, the more it will stand up to the constant beating it receives.
Field temperature: One of the greatest challenges to synthetic turf is its higher temperature over natural grass. Specially engineered fibers (AstroFlect, for example) reflect rather than absorb sunlight making them 10% cooler. Infills like Zeofill absorb water and slowly release it to contribute to an additional reduction in temperature. (Read more about the ways to combat heat issues on your synthetic turf here
Texturized rootzone: A texturized rootzone is the latest innovation in synthetic turf. High denier nylon fibers are “texturized” or drawn down and made curly by steam and then alternated with face fibers to hold the face fibers upright, much like a good quality natural grass field. Rootzone benefits include grass-like traction with reduced torque to lower extremities, less infill spray and improved durability and safety.
Backing: Turf fibers should be tufted through multiple layers of woven geotextile fabric and then a urethane coating fully applied. The backing provides strength to support the fibers while allowing water to freely flow through to the stone drainage layer beneath. Beware of thin backings or those that have only a partially coating on the backing.
Infill: Infill plays several roles in synthetic grass systems. In general, turf infills hold fibers upright and in place. Sand serves as a ballast to weigh down synthetic turf and provides similar footing to natural grass. Crumb rubber has long been the choice for turf infill due to its cost effectiveness. It helps absorb the impact of falls and plays a vital role in force reduction and Gmax ratings for safety. Much noise has been made about the risks of crumb rubber and to date there are no scientific studies detailing danger with respect to crumb rubber. We hold that it is more of a public relations issue than a medical one.
That said, replacing the rubber granules should be about designing entirely new synthetic systems with different infills rather than just swapping some other substance into a system intended for rubber infill. Some manufacturers have tried to sell a cork-based infill as an “alternative” to crumb rubber. However, installing cork in a low fiber/high infill synthetic system designed for rubber causes more problems than it solves, in our opinion. Cork floats and migrates during heavy rains. It also is not guaranteed for the life of the field and must be replaced every few years.
Sports Turf Company believes replacing the rubber granules is about matching infill with a system designed with that infill in mind. For example, ZeoFill and sand infill in a synthetic turf system with a high amount of fiber provides a fast surface that mimics a natural grass field while a pad provides force reduction similar to a natural grass field. ZeoFill, a mineral, absorbs 80% of its weight in water, provides a cooling effect for fields, has no “tire smell” and is the closest to crumb rubber pricing of all the infill alternatives. This is the newest technology that will change the industry for the next 20 years.
DIG: DIG represents a new understanding of the relationships in how key elements of synthetic turf design work together to improve field safety. Density is the quantity of turf fibers in surface pile; Infill is the amount of sand and rubber granules added to pile fibers; and Gauge is the distance between rows of turf fibers.
Lower fiber density, wider fiber rows and heavy turf infill lead to more cleat penetration and greater rotational resistance causing higher peak torques and leading to increased lower extremity injuries to ACL and high ankle sprains. Fields with more fiber density, narrow gauge between rows and lighter weight infill allow cleats to release properly and reduce lower extremity injuries.
This basic information about synthetic turf surfaces is courtesy of Sports Turf Company, Whitesburg, GA, which specializes in sports field construction and has 26 years of expertise pioneering technologies for building synthetic turf fields and proper drainage.