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Research Article

School Playground Surfacing and Arm Fractures in Children: A Cluster Randomized Trial Comparing Sand to Wood Chip Surfaces

  • Andrew W. Howard mail,

    andrew.howard@sickkids.ca

    Affiliations: Division of Orthopaedic Surgery, Hospital for Sick Children, Toronto, Ontario, Canada, Child Health Evaluative Sciences, Hospital for Sick Children, Toronto, Ontario, Canada

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  • Colin Macarthur,

    Affiliation: Bloorview Kids Rehab, Toronto, Ontario, Canada

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  • Linda Rothman,

    Affiliation: Child Health Evaluative Sciences, Hospital for Sick Children, Toronto, Ontario, Canada

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  • Andrew Willan,

    Affiliation: Child Health Evaluative Sciences, Hospital for Sick Children, Toronto, Ontario, Canada

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  • Alison K. Macpherson

    Affiliation: Department of Kinesiology, York University, Toronto, Canada

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  • Published: December 15, 2009
  • DOI: 10.1371/journal.pmed.1000195

Reader Comments (11)

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An industry association viewpoint.

Posted by CAPP-online on 21 Jan 2010 at 14:41 GMT

This article can also be found at:
http://www.capp-online.ca...

January 2010
The following statement is presented in response to questions arising from a study published (Dec 15, 2009) by Dr.
Andrew W. Howard that compares Fibar® Engineered Wood Fibre (EWF) to Granitic Sand (GS) with respect to upper
extremity, long bone injuries.
Note A: Fibar® is a specific proprietary product brand name of Engineered Wood Fibre playground surfacing material.
Although it was used as a reference name throughout this study, it should not be considered as a generic term for this type of material.
Note B: Granitic Sand is a geographically unique/specific type of sand material available.
Important: It should NOT be confused with the more traditional types of sand (ie: limestone based) available throughout North America.
School Playground Surfacing and Arm Fractures in Children: A Cluster Randomized Trial Comparing Sand to Wood Chip Surfaces
http://www.plosmedicine.o...
Please note that within our playground industry, studies such as this one are welcomed and appreciated. Statistical injury
data is the fundamental basis for the technical and dimensional criteria found within the National Standard of Canada for
Children’s Playspaces and Equipment (CAN/CSA-Z614). As such, we commend the efforts and time put into this study.
The Canadian Association of Playground Practitioners (CAPP) is a voluntary non-profit organization, comprised of
individuals who share a common goal of the promotion of appropriate playground environments. These playground
practitioners, by definition, have playground industry-related experience from a wide range of applications, including
playground inspection, retrofit/repair, supervision, management, design, manufacture, and sales of related amenities.
Some members have multi-disciplinary backgrounds, giving them the ability to consider a number of different aspects that
go into creating and maintaining a successful playspace.
Collectively, members of the Canadian Association of Playground Practitioners conduct thousands of playground
surface inspections annually. These inspection practices are performed to ensure compliance with the National Standard
of Canada for Children’s Playspaces and Equipment, CAN/CSA-Z614, which states the devices and procedures used to
evaluate playspaces and protective surfacing.
Product Comparability
This study focuses on two very specific proprietary surfacing products, “Fibar®” and “Granitic” sand. Yet part of the
title (“… Comparing Sand to Wood Chip Surfaces”) and the author’s conclusions both seem to suggest that the results
should be interpreted so broadly as to change our National Playground Standard. As noted earlier Fibar® is simply
one available type of EWF product, and similarly “Granitic” sand is simply one specific type of sand available. Neither
should be used as a comparative reference for all similar material types inclusive.
Variations in Product & Conditions
The author of the study also does not include the grain size distribution of the “Granitic” sand used in the study, only
acknowledging that the “Granitic” sand as “specified for this study has very uniform and very round particles”. Sand is
highly variable across Canada; it can vary pit-to-pit or even within the same pit. Particle size, shape, moisture content
and even contamination can play a significant role in its ability to absorb and distribute impact. Sand surfacing also
requires regular maintenance to redistribute material displaced during play. Loose-fill surfacing types in general (such
as pea gravel, wood-fibre, and sand) are all subject to moisture content, compaction and displacement through
weathering and normal usage. Compaction can greatly reduce shock absorbency while displacement moves
surfacing material from areas of greater wear, reducing the depth and therefore protection in some crucial areas. It is
noted that in the study recorded depths average 18cm (Table 1), where a minimum 30cm is not only recommended by
CAN/CSA-Z614 (Table D.2), but by most protective surfacing manufacturers, suppliers and inspectors.

Availability of Materials
“Granitic” sand is a very unique type of sand and not readily available to all regions in Canada, whereas Engineered
Wood Fibre is generally available across Canada and provides consistent test results for impact attenuation with a
relatively modest amount of maintenance. This geographically limited availability of Granitic Sand makes it impractical
Nationally as a material choice in many of our playspaces.
Accessibility
Providing accessibility to all users has long been recognised as a goal for playspace designers, manufacturers, and
owner-operators. Annex H of the CAN/CSA Z614 Standard provides guidelines in this regard. The displacement
properties of loose-fill surfacing such as sand or peastone actually impedes mobility and therefore these surfacing
materials cannot be used to provide accessibility in playspaces.
Note: as the referenced study was intended and focused only on the injury data properties of these two surfaces, it is
reasonable that this accessibility aspect was not considered. However, this aspect should remain a notable priority as
in reality the Owner/Operator of a playspace look to incorporate accessibility requirements in their playgrounds.
On the other hand, the properties of EWF surfacing materials have been recognised as a semi-unitary type of
accessible play surface, when properly installed. Currently in North America there are 3 separate standards that
pertain to the quality and performance characteristics of EWF including accessibility, heavy and tramp metals testing,
sieve analysis and impact attenuation. With the exception of impact attenuation testing, there are no other checks and
balances currently available for granitic sand.
In conclusion, we feel that a continuation of studies, which analyse in depth, the various properties of these two
products, and others, would provide additional valuable scientific background and contribute to playground safety in
Canada and to the ongoing improvement of all playground surfacing materials. To improve the state of the art, these
materials would have to provide qualities that help reduce debilitating or life-threatening injuries, reduce long bone
injuries, and maintain accessibility for the disabled. Unfortunately, Granite Sand does not provide accessibility.
Across Canada, in the last decade many playgrounds have been upgraded and now provide a much safer play
experience utilizing a variety of surfacing materials which meet the impact attenuation requirements of CAN/CSA-Z614.
Owner/Operators need to know that their investments have and will result in fewer serious playground injuries. We feel
further research is warranted before generalized recommendations can be made for changes to our National Playground
Standard.
Signed,
David DiPaola,
current President of Canadian Association of Playground Practitioners
Note: signed on behalf of the Association, after an open membership review and consensus agreement of the above document.
www.capp-online.ca

Competing interests declared: We are a National, independant and not-for-profit association of playground practitioners and as such we have no competing interests. However, some of our members may have competing interests.

RE: An industry association viewpoint.

Andrew_Howard replied to CAPP-online on 23 Jan 2010 at 09:03 GMT

Thank you to the industry association for additional practical information regarding reasons for and against surface selection.

We hope to have provided additional statistical information about real injuries of high scientific quality. We appreciate that a single study is insufficient to redefine a guideline but hope that high quality injury information is incorporated into the guideline process.

Our previous research, quoted here (CMAJ 2005) has indeed shown that removal of playgrounds which did not comply with CSA (1998) standards, and replacement with playgrounds which did, reduced injuries by about 50%.

We remain supportive of the application of guidelines and standards, particularly those which have been shown to reduce injury in the real world. Understanding and testing material properties is an important part of developing and applying such guidelines. Real world injury information, as provided in this study, should provide important data for consideration in the ongoing refinement of such guidelines. When we suggest updating the guidelines to reflect the new information, we certainly do not mean that the current study should replace any of the existing body of work. The types of considerations (availability of material, accessibility of playgrounds, costs) outlined here are important practical concerns for playground owner operators, as are injury rates.

Sherker (2004) has suggested that current playground safety standards may not fully prevent arm fractures because of limitations in current test methods and injury information.

In comparing a sand with an engineered wood fibre, we naturally selected the best available material locally for scientific and ethical reasons, and it was installed and tested in compliance with current standards on behalf of the Toronto District School Board. Generalizability of findings to a different setting is always an issue in applying the results of a randomized trial. The issue in this trial may depend on particular sands available. A combination of engineering analysis and injury information from a variety of sands would contribute to understanding the generalizability.

National associations such as CAPP play an important role in preventing childhood fractures. We appreciate their attention to, and critical consideration of, our research.

Competing interests declared: Study author

RE: RE: An industry association viewpoint.

Rogerwill replied to Andrew_Howard on 26 Jan 2010 at 13:04 GMT

Let’s not mince words. The study states that the standards should be adjusted to say that “(“sand”) surfaces should be recommended in preference to wood fiber surfaces”. This is not a suggestion for the addition of additional information. It is an assertion that the standard should recommend against the use of wood fiber.

It is bizarre that the study would make the profound revelation that sand is 5 times safer than woodchips based on the observations of 7 sand surfaces and present it as scientific proof that should change the standard.

Competing interests declared: manufacturer of EWF