Choosing the Right Playground Safety Surface
By Rick Dandes
It's no secret among safety experts and park managers that the majority of playground injuries suffered by children result from falls to the surface, often by tripping or by falling from playground equipment. Fortunately, the severity of these injuries can be minimized with appropriate protective surfacing material, which should be soft enough and thick enough to lessen the impact of a child's fall.
Protective surfacing is one of the most critical safety factors on playgrounds, agreed Caroline Boland, product manager of a Chattanooga, Tennessee-based surface and installation group. But, she also cautioned, keep in mind that "there is no perfect surfacing for playgrounds. All surfacing types have pros and cons. So it's important to choose the surfacing that meets the specific needs of your site and playground users. Minimally, all surfacing should be International Play Equipment Manufacturers Association (IPEMA) certified to AS™ 1951 and 1292, surface testing standards. This is very important no matter what playground surfacing you choose."
It wasn't always that way. In fact, not until 1975, when the Consumer Product Safety Commission (CPSC) analyzed playground safety hazards and guidelines, did the trend toward installing safer, shock-attenuating surfaces begin. After that study, woodchips, gravel, rubber and other "softer" materials began to replace harder surfacing materials like concrete, asphalt, hard-packed earth, grass and sand. And all those surfaces eventually had to meet guidelines first outlined in 1990, when the Americans with Disabilities Act was passed by Congress.
With all that to keep in mind, there are still basically only two types of playground surfaces, explained Jim Dobmeier, president and founder of a Buffalo, N.Y.-based surface manufacturer. One is called loose fill, and that ranges from sand and gravel to rubber chips and engineered wood fiber. The other general kind of playground surfacing is called bound material or unitary surfaces, and there are three general subtypes: poured in place, which is mixed and applied on site; tiles, made in factories, shipped on palettes and installed in the field; and a turf-type system that can have different types of underlayment. This surface can be a prefabricated material, a poured material or one covered with some type of synthetic turf.
Due to their features and inherent benefits, there are tradeoffs with every surfacing type, noted Robert Zeager, with a Middletown, Pa.-based manufacturer. "Because of their ability to move or displace when impacted," he said, "loose-fill material like engineered wood fiber and rubber mulch are generally believed to be better at preventing long bone injuries from falls, but they aren't as easy for children and parents who use wheelchairs to navigate and they are significantly more limited from a graphic design standpoint. That's why it's so important to choose the surfacing that achieves the primary objectives of your community's vision."
Jeff Anderson, parks development specialist, City of Columbus (Ohio) Recreation and Parks Department, offered some practical advice for parks and recreation departments looking to find their best, most appropriate surface.
Engineered wood fiber, he said, is "the most cost effective option for playground surfacing, and for initial installation. It is ideally used in large play areas, high fall heights, swings and natural play areas. It meets AS™ standards for accessibility and impact attenuation. It's also true that natural wood material is an aesthetically appealing fit for a park setting. While EWF works well on most playgrounds, on certain playgrounds where there is an increased emphasis on universal accessibility we are more likely to have the entire surface be unitary in order to maximize access to all parts of the playground."
Where therapeutic recreation and universal accessibility are of concern, the entire playground has a unitary surface, Anderson said. If parks and playgrounds are naturalized, there is an emphasis upon EWF for the surfacing.
Many playground owners believe using a wood chipper to chip downed trees is the same as the engineered wood fiber sold by playground companies, but that's just not true, he continued. Never go with mulch or wood chips that are not certified for playground use. They could contain metals, chemicals or worse, and have no guarantee of fall cushioning properties. EWF contains a precise formula of fine and larger particles to ensure proper compaction for wheelchair accessibility and fall cushioning.
Bonded wood fiber is another choice that looks natural, and is pervious and accessible. Using it reduces maintenance of EWF and reduces blowing or scattering wood fiber. It is ideally used in natural play areas and to increase accessibility. "The one caveat about this surface is it requires a certified installer," Anderson said.
Artificial grass looks natural and clean. This surface is ideal for child care centers and nature-themed play areas. Rubber tiles are a wonderful solution for densely populated urban play areas. Both artificial grass and rubber tiles require certified installers.
A poured-in-place rubberized safety surface is perfect when accessibility is the priority, Anderson said. "It's attractive and easy to maintain, and available in a variety of colors. It allows for additional play areas, especially for younger children, and it is least affected by rain events. The surface is playable sooner."
Maintenance and Life Cycles
Different surfacing types have different life cycles. Whatever surface you select, good maintenance and proper care for the material can significantly extend its life.
"Choosing a company that offers a maintenance program can also help greatly increase the lifespan," Boland explained, "by performing key treatments at relevant times in the surface's life. Roll coating, adding a urethane coat, helps rejuvenate and strengthen the surface. The ability to patch is important to help repair potential damage from vandals, including holes or cuts that may become trip hazards."
In these cases, she added, replacement of the entire surface is not usually necessary, as opposed to being able to address the damaged area exclusively. "Amazingly, you can actually entirely re-top an existing poured-in-place surface as long as the system is in serviceable condition. There's a lot that surfacing experts can do to help playground owners save cost in the long term."
Loose-fill materials such as engineered wood fiber and rubber mulch are initially more cost-effective, but do require regular maintenance to keep the proper thickness protection under swings, at the ends of slides and in other high-traffic areas. Loose-fill surfacing can hide unwelcome objects on a playground, such as broken glass, sharp metal pieces or other items that can be injurious to a child and even compromise the safety level of the playground surfacing. Loose-fill surfacing requires borders such as plastic or wood timbers or concrete curbs to contain the materials and some unusual shapes of playgrounds may not be possible.
"For our EWF playgrounds," Anderson said, "ongoing work includes maintaining a proper depth, grade and removing weed growth. Besides regular maintenance, our staff also works with local residents to organize volunteer events, spreading new EWF on the playgrounds. Repairs and replacements of unitary safety surfacing is typically limited to the cap layer and replaced by contractors."
ADA Requirements and More
Under and around playground equipment, it is important to make sure that the surface cushions falls and is wheelchair accessible. Poured-in-place rubber enables children with limited mobility to actively play alongside their peers. Poured rubber surfaces can also offer play value aspects, through the creation of inlaid patterns and games, and even by embedding sound chips so that the surfacing makes sounds when stepped on. The possibilities are endless!
Some municipalities might want to consider incorporating multiple surfacing types into a single park site. For example, a tile area around the slides and access points promotes highly accessible play pathways for looping play, where children choose to do the same activities again and again in loops, and EWF can then be placed under high decks and adjacent open space. Combining multiple surfacing types can sometimes be more economical. Various surfacing types offer tactile transitions that promote sensory development for children with and without disabilities.
"Clearly, a unitary safety surface tends to appear more accessible and welcoming to individuals with limited mobility," Anderson observed. "One approach that we have used in Columbus is to provide a unitary surface arrival space between the transfer station for the playground and one or two accessible play elements. This makes it easier for individuals to reach the playground but is less costly than installing unitary surfacing on the entire playground.
It's important to remember that fall cushioning and accessibility is required throughout the life of the playground—not just when it is first installed, so ongoing maintenance is very important. For loose-fill materials, maintenance includes raking the material into place in high-use areas where it may get kicked out. This is especially prevalent under swings and at the base of slides. Topping off is also important for loose-fill materials. Over time, the material can wash away, degrade, or children could carry it out of the playground. Add more material when the original material becomes low."
Other things to keep in mind: EWF can be uncomfortable with open-toed shoes. Wood splinters are a potential. And drainage can be an issue, Anderson said.
Agreeing with Anderson, Dobmeier added, "The reality of all loose fill is that you need a certain depth of that material to meet shock attenuation requirements. Don't get me wrong, there are certainly some loose-fill materials that are accessible and meet the ADA requirements, in particular, wood chips. But in reality, those loose materials, unless you have people out there monitoring and raking and filling on a daily or weekly basis isn't always at a proper depth. Children fall. The loose fill is supposed to be 12 inches deep, but in high-traffic areas, it might be only three inches deep. The beauty of bound material is that the shock attenuation standards are consistently met for many years.
Here are some other things to consider:
- Concrete, asphalt, and blacktop are unsafe and unacceptable. Grass, soil and packed-earth surfaces are also unsafe because weather and wear can reduce their capacities to cushion a child's fall.
- The surfaces may be loosely filled with materials like wood chips, mulch, sand, pea gravel or shredded rubber. Wood chips containing chromated copper arsenate (CCA) treatment are not recommended since the material can pose a potential health hazard.
- Surfacing mats made of safety-tested rubber or rubber-like materials are also safe.
- No surfacing materials are considered safe if the combined height of playground and the child (standing on the highest platform) is higher than 12 feet.
- The cushioned surface should extend at least 6 feet past the equipment. Additional coverage may be needed, depending on how high a slide is or how long a swing is.
- If there is loose-fill over a hard surface (like asphalt or concrete), there should be 3 to 6 inches of loose-fill like gravel, a layer of geotextile cloth, a layer of loose-fill surfacing material, and then impact mats under the playground equipment.
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