The last important detail
The technical aspects of playground surfacing start with the CPSC Handbook for Public Playground Safety. “Because head impact injuries from a fall have the potential for being life-threatening, the more shock-absorbing a surface can be made, the greater is the likelihood of reducing severe injuries.
Biomedical researchers have established two methods that may be used to determine when such an injury may be life-threatening. First, impact attenuation holds that if the peak deceleration of the head during impact does not exceed 200 times the acceleration due to gravity (200 G’s), a life-threatening head injury is not likely to occur.
The second method holds that both the deceleration of the head during impact and the time duration over which the head decelerates to a halt are significant in assessing head impact injury. The mathematical formula to derive a value known as Head Injury Criteria (HIC) that is not believed to be life-threatening should not exceed a value of 1000.” (Handbook for Public Playground Safety, CPSC 1997, p. 4-5.)
These formulas are tested through a series of drop tests at properly installed depths. In the “real” world, proper depth of loose-fill material is left to the knowledge and expertise of the playground installer. Then, once installation is complete, those in charge of maintenance are charged with the responsibility of maintaining proper depth. The exact thickness and mixtures of “poured-in-place” should be installed exactly to manufacturers’ directions for the same reason.
Attention to detail is the first rule of thumb for installing playground surfacing. These details include edging or borders, sub-base materials, and drainage system. Surfacing installation occurs during the final phase of the playground installation but should not be considered an afterthought. It affects the overall look of the finished product, the stability, and integrity of the playground, as well as compliance with safety standards.
Sometimes the installation company is not responsible for surfacing installation. Communicate with the company who is installing the surfacing so they have materials arrive in ample time. The key is to get surfacing under the playground as quickly as possible to close the window of liability exposure to ensure a safe play area for children.
Loose-fill products such as sand and pea gravel have been used as a fall resilient surface for decades. However, sand and gravel do not meet ADA requirements and can harden over time and if not kept clean and maintained.
When bringing loose-fill materials to playground areas, don’t allow truck drivers to damage curbs, sidewalks, turf, or sprinkler systems. Dump the materials in an area that can be cleaned up, and don’t throw sand and gravel on or against the equipment. This could cause the finished coats to scratch or chip.
Engineered Wood Fiber, more commonly known as wood surfacing, is a more popular resilient playground surface. This product should only be purchased through a reputable company that can certify that their product has been tested according to the standards above. Never purchase recycled wood. It could be contaminated with nails, metal, disease, wire, or any number of impurities.
Wood surfacing also comes in large trucks or tractor-trailers. It may be tough to maneuver a 70-foot long vehicle to the playground. Be aware of overhead power lines, trees, or other obstacles. Be cognizant that children may be present. Big trucks can break curbs, sidewalks, and sprinkler systems. They also leave big holes in the ground is wet or soft. Using tarps when unloading may make cleanup easier.
Always rake and sweep the area where surfacing was dumped. Do not put contaminated product in the playground. When using front-end loaders, be careful not to scoop grass or dirt into the wood, and follow the manufacturer’s specifications for installing the wood as well as weed barrier material that comes standard with the purchase of this product.
Loose-fill rubber is generally some type of recycled tire product. For peace of mind and to assure the owner the product has been manufactured for use under and around playgrounds, ask the manufacturer for documentation. Loose-fill rubber comes in bulk in trucks or huge bags that require a forklift or crane to lift. Care should be taken when accessing the playground pit. Unload and install loose-fill surfacing.
Unitary tiles are another popular choice for surfacing and are also usually made from recycled rubber. Patience and experience are key to cutting tiles perfectly around playground parts. Layout of unitary tiles is important. Tiles must remain true and square.
Poured-in-place rubber surfacing consists of a granulated top surface over a resilient base material forming a seamless surface. The essential factors for proper poured-in-place installations are a solid sub-base, edging, temperature, accurate mixing, and the experience of the installer. The sub-base should be concrete asphalt or 95 percent compacted base material. Weather and temperature, including humidity and precipitation, directly affect the outcome of a proper poured-in-place project. It is also critical that installers strictly follow the manufacturer’s instructions for keeping the material dry, protecting the job site, and effectively maintaining.
Lastly, and quickly becoming a very popular surfacing choice, is the two-layer surfacing systems that consist of a shock-absorbing base material with a stronger top layer that protects the base material while providing durability where it’s needed most. Like tiles and poured-in-place, two-layer systems also require a compacted base and sturdy borders. This type of surface system is often referred to as a “floating system,” as the base material sits on the sub-base and the top layer is secured only to the perimeter border.
Installers are the last link in the playground process and installation of surfacing is the last job to be done before children can begin enjoying their new playground. It is the installer’s responsibility to understand the nuances of each surfacing option. There are inherent challenges and benefits of each type of surfacing product.