Professional athletes don’t like artificial turf for many reasons, and many parents feel the same way about artificial turf playgrounds and athletic fields. Artificial turf is made with chemicals that can harm children and adults, the fields also are much hotter than grass, and bacteria can grow in them. This article will focus on a different safety issue: the hardness of the field and implications for the safety of children and adults playing on them.
How is hardness measured?
Gmax scores are used to measure field hardness. The hardness is supposed to be measured at 10 spots on the field, and to be considered safe, all 10 points must not exceed a safety cutoff limit. If the score exceeds the limit on any of the 10 test locations, the field is considered “out of compliance” – in other words, unsafe.
What is the score that indicates the field is safe?
The National Football League (NFL) uses a Gmax score of 156 before each game.
A Gmax score of 165 is the limit recommended by the Synthetic Turf Council, which is the trade association for the synthetic turf industry. Ryan Teeter, the consultant that the District of Columbia hired to replace the failed fields with new synthetic turf, clearly states on his website that no spot on a field should exceed 165.
A Gmax score of 200 is the ASTM standard. ASTM is a private standard-setting entity. They consider a score of over 200 as indicating a skull fracture is probable and fatal head injury is possible. However, this standard was set before physicians fully understood the damage of repetitive concussions or sub-concussive head injuries. And yet, the District of Columbia is currently using a Gmax of 200 as the minimum for field replacement and repair. There are many fields in the District that have Gmax scores above 190 that the city is not planning to fix.
How Dangerous are the Playgrounds and Fields in Washington, D.C. in 2017?
Unfortunately, they didn’t test playgrounds with slides and swings, which can get dangerously hard. Of 57 “synthetic grass” fields managed by the city that were tested in 2017, the city decided to repair or replace 16 fields due to Gmax scores above 200. Ten were repaired, 3 were replaced, and 3 were put back into service without repair or replacement.
If the city used the Gmax cutoff of 165 instead, which is what the Synthetic Turf Council recommends, an additional 21 fields would be considered unsafe based on 2017 Gmax scores. They include the following examples:
- The field at Hardy Middle School scored above 165 in 6/10 locations on April 22, and above 165 on 2/10 locations on July 11.
- The field at Key Elementary School scored above 165 in 5/10 locations on June 5 and 6/10 locations on June 28. On June 28, one spot had a Gmax score of 194.5.
- The field at Turner Elementary School scored above 165 in 2/10 locations on June 29, including a Gmax score of 190.5 in one spot.
- The field at Joe Cole Rec Center scored above 165 in 4/10 locations on June 30.
Of the 16 fields scheduled for replacement or repair, there were 9 that were repaired and re-tested in August, and 3 that were re-tested and put back in service without repair. 8 of the 9 repaired fields would be considered unsafe after the repair based on the Synthetic Turf Council standard of 165. They include:
- The field at Bell/Lincoln (Columbia Heights EC)had a Gmax score above 165 in 3/10 locations on August 18.
- The field at Jellef Rec Center scored above 165 in 1/10 locations on August 17.
- The field at Parkview Rec Center scored above 165 in 7/10 locations on August 21, including scores of 190.5 and 191. On average, the field was harder on August 21 than in previous tests on April 11 and June 28.
- The field at Upshur Park scored above 165 in 1/10 locations on August 18.
The 3 fields put back in service without repair or replacement would all be considered unsafe based on the standard of 165. Among these are:
- The field at Ross Elementary School scored above 165 in 6/10 locations on August 22, including a score of 191 in two locations.
- The field at Tubman Elementary School scored above 165 in 5/10 locations on August 22, including scores of 187 in two locations.
When there are two different sets of test results on the same field without any repair or replacement, it reflects changes due to weather and testing conditions. However, once a field has a dangerously high test score, it will revert to that score or a higher score in the future when the weather conditions are more problematic.
Remember that the average of Gmax scores on any field is irrelevant. What matters is that a child or adult can be hurt on the parts of the field where the scores show the field is dangerously hard.
And if you’re a parent, ask the Mayor and City Council why they haven’t tested the playgrounds where young children play on slides, swings, and monkey bars.
All articles are reviewed and approved by Dr. Zuckerman and other senior staff.