SYNTHETIC TURF quickly under clear , hot , sunny conditions , the fields do not act as a heat sink . While the surface can have very high temperatures , the air temperatures measured two and five feet above the surface are typically only 5 ° F to 10 ° F higher than ambient air temperatures . Heat is not stored because synthetic turf fibers reflect solar radiation and the infill acts as insulation limiting transfer of heat into the system . Therefore , at night or under cloud cover , surface temperatures quickly approach the ambient temperature . During clear , sunny conditions , it is suggested that sports field managers , coaches and trainers monitor heat index and surface temperatures and make appropriate adjustments to practice and game schedules . It is strongly recommended to use an infrared thermometer to easily monitor surface temperatures .
FIELD HARDNESS The hardness of a surface has been identified by numerous entities as an important parameter of athletic surfaces . Gmax testing , also known as impact testing ,
measures the shock attenuation of both synthetic turf and natural turfgrass athletic fields . Surface hardness is measured by dropping a weight ( referred to as a missile ) from a fixed height onto the playing surface . The missile contains an accelerometer that measures how fast the missile stops once it hits the surface . A numerical value , referred to as Gmax , is then generated . A high Gmax value indicates the missile stopped quickly and the surface is harder than a surface with a lower Gmax . Harder surfaces may influence athlete injury . Gmax should be tested at numerous locations across the field , with special attention being paid to high-use locations , such as mid-field areas and goalmouths . At a minimum , testing should occur yearly , but more frequent testing is desirable as field conditions may vary throughout a season .
Various measuring techniques have been developed to evaluate playing surface hardness . ASTM International has designated the ASTM F355 Missile A device in ASTM F1936-19 , Standard Specification for Impact Attenuation of Turf Playing Systems as Measured
“ We have NorthBridge on the diamond at baseball and also NorthBridge on the outfield of baseball … and we did the same at softball . The cultural information in the industry was NorthBridge is the better grass . And so that was my vote to administration .”
– Jon Dewitt – Athletic Grounds Director – University of Alabama
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