Equipment/Facilities: Sand is Significantly Safer Than Wood Fiber as a Playground Surface

Dick Moss, Editor, PE Update.com

If your school is installing new playground equipment, you might be wondering which ground surface is the safest?

A recent study by Toronto's York University and the Hospital for Sick Children has come up with a definitive answer. Of the two traditional surfaces, sand and wood fiber, sand is almost five times safer!

The Study
The study examined 28 elementary schools in the Toronto District School Board with one group installing granite sand surfaces and the other group using engineered wood fiber (called Fibar).

Injury data was collected and compared after 2.5 years of use.

The results were unequivocal. Students who fell onto a wood fiber surface were 4.9 times more likely to break an arm than those falling onto sand!

The actual rates were 9.4 injuries per 100,000 students for wood fiber versus 1.9 injuries per 100,000 for sand.

Previous studies have shown that sand is also safer than either grass or asphalt as a protective surface [2]. Bark surfaces (not the same as engineered wood fiber) have been shown to be little different than concrete in preventing injuries [3].

Explanation
The researchers believe that granite sand is composed of round, uniform particles that minimize friction. As a result, an arm or hand that contacts the surface sinks or slides very easily, reducing sudden impact stresses. It has previously been shown that sand surfaces possess lower surface friction than Fibar counterparts [4].

Why is Wood Fiber Often Preferred?
So why is wood fiber often preferred as a playground surface? Many schools are reluctant to install sand because of its potential to be thrown at other students, to be soiled by cats and dogs and to be tracked into the school. However, this may be a groundless worry. During this study, no injuries because of thrown sand, and no soiled sand was reported.

References:
1.     Andrew W. Howard, Colin Macarthur, Linda Rothman, Andrew Willan, Alison K. Macpherson, “School Playground Surfacing and Arm Fractures in Children: A Cluster Randomized Trial Comparing Sand to Wood Chip Surfaces,” Public Library of Science Medicine, December 15, 2009. http://www.plosmedicine.org
2. Sosin DM, Keller P, Sacks JJ, Kresnow M, van Dyck PC (1993) Surface-specific fall injury rates on utah school playgrounds. Am J Public Health 83: 733–735.
3.     Mott A, Rolfe K, James R, Evans R, Kemp A, et al. (1997) Safety of surfaces and equipment for children in playgrounds. Lancet 349: 1874–6.
4.     Chesney DA, Axelson PW (1996) Preliminary test method for the determination of surface firmness. IEEE Trans Rehabil Eng 4: 182–187.

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