What lies beneath: learn the pros and cons of a variety of surfacing solutions

Parks & Recreation, Nov, 2005 by Anne-Marie Spencer

One of the most important aspects of providing a safe play environment is the installation of high-quality surfacing with proper impact attenuation properties. When installed correctly, safety surfacing greatly reduces serious injuries that can occur if children fall from the play structure.

We've come a long way since the mid-'70s, when it was not uncommon to find playgrounds with concrete or asphalt surfaces (with asphalt being the preference as it was "softer" than concrete). Unfortunately, serious injury was a regular occurrence, and both material providers and facility owners sought to provide a surface that was softer to help attenuate falls and reduce injury. At that time, sand and pea gravel were both readily available and inexpensive, and were generally accepted as a better alternative than the hard surfaces of the past.

However, sand became hard when wet, and was often polluted by animal waste. Both surfaces were easily thrown by children and were difficult to walk or run in. Then, with the advent of the Americans with Disabilities Act (ADA), the surfacing industry evolved again, as the product now needed to provide a firm, stable and slip-resistant footing for mobility devices to wheel across, which was not possible with either sand or gravel.

There are several industry-accepted playground surfaces available that provide the cushioning properties needed, as well as the firm stability required for the ADA. Because the industry is constantly experimenting, and new surface products are introduced on a regular basis, park and recreation managers should know the benefits and drawbacks of the most commonly accepted types of surfacing, in order to make the choice that best suits any play area.

It also helps to be familiar with two sets of federal guidelines: the U.S. Consumer Product Safety Commission's (CPSC) Handbook for Public Playground Safety (CPSC Pub. 325) and the U.S. Access Board's ADA Accessibility Guidelines for Play Areas, covering compliance under the ADA. According to these publications, playground surfacing must allow children to approach and enter the playground safely, as well as minimize the risk from falls.

When planning a play area, your playground manufacturer will calculate its "use zone." This zone includes all surfaces under the equipment, as well as the distance outside and around the equipment that a child may fall in the normal course of play. The use zone is the minimum area that surfacing should be placed in, though some play environments extend the use zone to increase the play area or enhance the surrounding environment. The depth of surfacing required depends on the height of the play equipment, and the type of surfacing used.

A critical fall height (CFH) is assigned to the components within the play area, and is defined as the "fall height below which a life-threatening head injury would not be expected to occur." The CPSC Handbook indicates recommended depths of materials calibrated to various fall heights. For example, nine inches of compressed wood chips will protect children falling from a height of 10 feet, while the same depth of coarse sand only protects from a fall height of four feet, less than half the distance. Although it may cost more, six inches of shredded rubber protects children from fall heights of 10 to 12 feet.

So what are the choices and benefits of each type? Surfacing can be divided into two groups: loose fill--such as wood fiber and rubber chunks; and unitary, or solid surfaces, such as bonded or poured rubber. Generally speaking, loose fill surfaces are less expensive, but may require more maintenance during the life of the product. They require adequate drainage, as well as containment borders to prevent migration outside the play area.

They should also be installed over an underlayment of geotextile fabric, to prevent mixing with the under surface and "grow through" of plant material. Choosing wear mats to lay on the surface in areas like the base of swings and slides, can help prevent displacement. Loose fill surfaces are also harder to keep clean, as trash can be mixed in and not easily noticed. Some may not provide adequate accessibility.

Solid or unitary surfaces provide excellent ADA accessibility. Unitary surfaces will not require topping off, and are easy to clean, saving maintenance costs throughout the life of the product. They do, however, require a higher initial investment than with loose fill surfaces. They must be installed over a prepared hard surface, like concrete or asphalt (or in some cases, crushed stone) and proper drainage is important. They must not be installed over grass or gravel. Unitary surfaces, because they are more unyielding than loose fill materials, may also result in more finger breaks after a fall to the surface.

So how do you choose what's right for your area? Jim Pryor, director of parks and recreation for Kernersville, N.C., says that they considered the initial investments, then chose bonded rubber surface product for their playground. Pryor adds, "We have used most all types of surfacing, and felt that the low maintenance associated with this product was well worth the initial investment.