Sources of Heat in Synthetic Turf Systems

With options for cooling synthetic turf limited, an outdoor experiment was conducted at the University of Tennessee Center for Athletic Field Safety (Knoxville, TN) to develop a model to predict maximum, minimum, and mean synthetic turf surface temperature using forecasted atmospheric conditions. Synthetic turf surface temperature varied due to both air temperature and solar radiation. Predictive models using these data accounted for 86, 95, and 94% of the variation in daily maximum, minimum, and mean synthetic turf surface temperature. Accuracy of these models for predicting daily mean and minimum synthetic turf surface temperature using 48 and 72-hour forecasted air temperature data was +/- 1 °C, while the daily maximum synthetic turf temperature (+/- 4.7 to 5.3 °C) was less accurate.

Infilled synthetic turf contains several components that may affect surface temperature including the aggregate base layer, crumb rubber and silica sand infill, synthetic turf backing, and polyethylene pile fibers themselves. In a glasshouse study at the University of Tennessee (Knoxville, TN) each component of an infilled synthetic turf system was placed in a controlled rise temperature chamber for 4 hours with surface temperature monitored. Surface temperatures for components containing pile fibers were 15 °C greater than those without fibers. No differences in temperature were observed among fibers with and without crumb rubber infill. These data indicate that fibers affect surface temperature on synthetic turf more than other components.

Research was also conducted at the University of Tennessee investigating methods for reducing surface temperature on infilled synthetic turf again in a controlled temperature rise chamber for 4 hours, including the use of reflective pigments, fans, and water absorbent pads placed below the turf surface. Results from this study indicate the greatest reduction in surface temperature (32 °C compared to the control) was the fan applying forced air to the surface. In addition, reflective pigments and sub-surface forced air applied through the aggregate base each offered lower surface temperatures than the non-treated control. Applications of forced air to the surface were further tested in a field study. In the field studies, the forced air significantly reduced surface temperature compared to non-treated controls.