Safeguard Your Assets
By Thomas Shay
Just as one would maintain a house to improve its longevity or design a car with airbags for safety, proper design, maintenance, and use are required for synthetic-turf fields. Without these elements, the field warranty may not be worth the paper it is written on; further, athletes will be at risk for injury, and the owner could potentially be liable.
Planning and designing an athletic field should be as much about safety as performance. The key user-group age and sport should be identified, and the field section (i.e., the subsurface components) should be designed for that group. Part of the design process includes not only product and performance requirements, but other important items, such as maintenance equipment and warranties.
Key Maintenance Activities
One myth surrounding synthetic-turf fields is that they do not require much in the way of maintenance. While maintenance is reduced when compared to that necessary for natural-grass fields, it cannot be eliminated. There are simple yet important steps that an owner or operator should take to inspect and maintain a synthetic-turf field:
Impact testing—Commonly referred to as G-Max testing, impact testing should be completed at least annually on all athletic fields. Ideally, the G-max for a synthetic field should mimic that of a quality natural-grass field. By comparison, a professional-level, appropriately maintained, natural-grass field may have a G-max of approximately 70-90 g’s. G-Max levels should always remain below 160 g’s. As a precaution, an owner should consider closing a field until it can be returned to acceptable G-max levels if any area of the field is approaching 160 g’s.
G-max testing should be completed by a qualified third-party contractor to ensure that the appropriate method is followed, the testing is completed to ASTM standards, and the results are accurate. The field owner should receive a report with a summary of the test, including G-max levels, corresponding infill depths, and a diagram of the testing locations.
One way to maintain a safe G-max level across a synthetic-turf field is to incorporate a shock pad in the base design. Some shock-pad manufacturers guarantee the highest G-max levels, which is a great benefit to owners when considering performance and player safety. Data show that with the inclusion of a properly designed field cross-section, the G-max level of a synthetic-turf field is held closer to 100 g’s. It is also possible to retrofit an existing synthetic-turf field with a shock pad during replacement of the turf carpet at the end of its useful life.
Monitor infill depth—One of the most concerning injuries associated with a poorly maintained and substandard designed athletic field is head trauma from an impact with the playing surface. To help reduce the probability of an impact-related injury, infill depth should be monitored regularly to ensure that minimum depths are achieved and infill is evenly distributed throughout the field. This is especially important in highly used areas around goals, corner kick spots, mid-field, between the hash marks, and at baseball/softball bases where the infill is displaced. The shock-absorption capability will be reduced in areas where the infill is displaced, which leads to potentially unsafe playing conditions. Infill can be measured with a simple, affordable probe. The key to accurately measuring the infill is to make sure the probe end on the gauge extends all the way to the synthetic-turf backing.
Sweeping and grooming—Sweeping the surface will remove litter such as garbage, dirt, and leaves. Grooming will reduce infill compaction, redistribute the infill, and help raise the turf fibers. The frequency of these activities is dependent upon how often the field is used, and the owner should work with the manufacturer to set up a schedule. The equipment necessary to sweep and groom the field surface is typically provided to the owner once the field is installed and accepted in writing as complete. The turf manufacturer should train the staff that is responsible for completing the field maintenance. Note that it is possible to over-groom a field, resulting in premature breakdown of the turf fibers, and aggressive grooming of an older field may be harmful.
Keep a log—The entity responsible for maintaining the field and that holds the warranty should keep an inspection and maintenance log documenting the condition of the field and all maintenance activities performed. At a minimum, each entry should include the date, the person(s) completing the work, the type of work, and a detailed description of field conditions. This log will be valuable should a warranty-related issue arise, as a maintenance log is typically required as part of the warranty claim. The log provides evidence that a maintenance program is in effect and that proper inspection and maintenance activities were performed.
Many tasks associated with field maintenance are common sense, such as taking special care when snow-plowing the field, looking for tears or issues with seams or logos, and cleaning the surrounding drainage infrastructure that might clog and flood or contaminate the field with sediment. The challenge lies more in ensuring that established maintenance activities are completed in the right way, and at the right time. When in doubt, contact the manufacturer or a design professional.
If the thought of performing the required inspections and maintenance is daunting, one option is to consider a maintenance agreement with an authorized and properly trained third-party contractor, or even the manufacturer of the synthetic turf. The contract could include all inspection and maintenance activities, or it could supplement the activities performed by the owner. Sometimes it is reassuring for an owner to have the manufacturer perform regularly scheduled maintenance due to the firm’s expertise with the various field systems and its ability to evaluate or identify potential issues before there is a bigger problem.
Proper Use And Operations
Other considerations related to operations include providing staff with appropriate training, such as requiring users to alternate areas of the field for repetitive drills, which will help maintain infill depth. The other main safety-related concern with synthetic fields is the intense heat. On summer days with severe sunlight, the surface of a synthetic-turf field will routinely exceed 150 degrees Fahrenheit and may reach 200 degrees Fahrenheit.
Athletes can be protected from heat-related issues by planning accordingly during days and months with high-intensity sunlight. Players, coaches, trainers, and parents should be educated on the signs of heat stress. Players should have access to liquids for hydration and cooling, and facilities can provide players with shaded areas or misters to cool down.
Researchers at Pennsylvania State University evaluated various methods to reduce synthetic-turf surface temperatures, including irrigation, and none were successful for extended periods of time. There are some newer alternative infill products on the market that reportedly provide a significant cooling effect—but they need to be evaluated further. The use of irrigation and increased maintenance are required beyond the more standard crumb rubber/sand infill system.
Thomas P. Shay is a Project Engineer at Woodard & Curran, an integrated engineering, science, and operations firm. He is a licensed professional engineer specializing in athletic-field and recreation-facility design in Woodard & Curran’s White Plains, N.Y. office, and a former college athlete. Reach him at email@example.com.