The latest records requested by Non Toxic Portsmouth reveal that the Gmax or hardness level of Tom Daubney Field far exceed the threshold set by both the University of New Hampshire and the National Football League.
Testing done for the City in October of 2021 showed a Gmax of 199 – just one point below the outdated and dangerous 200 Gmax threshold used by the School District.
According to Diana Zuckerman PhD, President of the National Center for Health Research, “A Gmax score over 200 is considered extremely dangerous, and it is considered by industry to pose a death risk. However, the synthetic turf industry and American Society for Testing and Materials (ASTM), suggest scores should be even lower — below 165 to ensure safety comparable to a grass field.“
The Synthetic Turf Council recommends a more protective limit of below 165 Gmax using the F355 scale. The NFL uses a different testing tool (Clegg) with a lower scale and sets their limit at about 100 Gmax and test prior to each game. 135 Clegg = 200 F355.
Natural grass fields typically measure 42 Clegg or 85 F355 units.
Portsmouth School District is taking unacceptable risks with the safety of the players using the synthetic turf field when they use the 200 upper limit set by the U.S. Consumer Products Safety Commission. “The 200 G-MAX level set by the CPSC is intended only to protect field owners from civil liability should horrible injury occur,” according to the STMA.
There is very good reason to question the validity of the upper Gmax limit of 200 in light of advances in research on injury prevention.
This report also averages the numbers. All points on the field must be below the limit, not an average. Children do not fall and hit their heads on averages.
The hardest point measured on the field is 199 Gmax which is well above the more protective upper limit of 165. Had this field been installed at the University of New Hampshire it would have been removed and replaced years ago, the same if it were an NFL field. They both keep field hardness below 165.
Listen to the testimony of Dr. Greg Guyton, orthopedic surgeon to NFL Ravens, regarding safety and playing on post-warranty fields like the one at PHS. Begin at 1 hour 6 minutes of the video for his 2 minute testimony.
This video on Gmax testing also explains why the 200 cutoff is not adequate, and a result of 165 still needs to be remediated.
Are the brains and bodies of Portsmouth High School athletes deserving of lesser protections than college students and professional athletes?