Safety Surfacing Protecting kids from falls by Michelle d'Hulst Each year, nearly 148,000 children are treated in U.S. hospital emergency rooms for equipment-related injuries that occurred in public playgrounds. Also, about 15 children die each year due to strangulation or falls. The Consumer Product Safety Commission reports that 60% of all playground-related injuries are caused by falls to the ground. In its Handbook for Public Playground Safety, The CPSC placed great emphasis on protective surfacing as a critical safety factor. As a specifier, Landscape Architects are actively involved in preserving the safety of our nation's parks. Based on the height of the equipment and the type of surfacing material, the CPSC has developed a Critical Height specification for use in public playgrounds. The critical height of a surfacing material is the approximate maximum fall height from which a life-threatening head injury would not be expected to occur. Manufacturers of safety surfacing are also required to submit their products for critical height testing. Two primary methods are used to predict the threshold tolerance of the human head to an impact injury. 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 determining head impact injury. The CPSC is responsible for evaluating the shock absorbing properties of playground surfacing material. They drop an instrumented metal headform onto a sample of the material and record the acceleration/time pulse during impact. For example, If nine inches of compressed fine sand is installed, then the play equipment in that park should not exceed five feet. The CPSC standards act as a guideline, but check with individual manufacturers for the shock absorbency of their product lines. Playground surfacing falls into two basic types, unitary or loose-fill. Rubber mats, pour-in-place surfacing or a combination of rubberlike materials all fall under unitary surfacing. Since these products are made specifically for playground surfacing, request test data from the manufacturer to determine the Critical Height and installation depth. Loose-fill materials-sand, gravel, and shredded wood products-must be installed at specific depths to provide adequate cushioning. Loose-fill materials should not be installed over hard surfaces such as asphalt or concrete. Organic loose-fill materials, such as wood chips, engineered wood fibers and bark mulch, have many pros and cons. Advantages include: low initial cost, ease of installation, good drainage, less abrasive than sand, less attractive to cats and dogs, attractive appearance and readily available. The CPSC listed some disadvantages to organic loose-fill materials that may reduce cushioning potential: 1) Environmental conditions like rainy weather and high humidity, 2) combines with dirt and other foreign elements, 3) can decompose, compact and be pulverized over time, and 3) depth may be reduced by children's activities or neighborhood theft for use as garden mulch. Playgrounds that are surfaced with a loose-fill material will need to be maintained to ensure that a specified depth is maintained. Inorganic loose material such as sand and gravel are considered easy to install and the materials are readily available. Sand and gravel does not promote microbial growth, they are non-flammable and not susceptible to vandalism. Fine sand offers 9 feet of critical height when it is installed at a depth of 12 inches or greater. Sand is very attractive to neighborhood animals and it can also cause slip and fall accidents when it spreads beyond the confined playground environment. A new development in the safety surfacing market is shredded rubber products. The Quantum Group Inc., based in Tustin, California, reduces scrap truck and automobile tires to crumb rubber that is then used to create over 200 diverse products including a pour-in place safety surfacing and rubberized mats. Quantum has built its first U.S. factory inside Donovan State Prison that employs 40 minimum-security inmates. Recycled rubber products are used to make pour-in-place surfacing and shock absorbing tiles. The manufacturers of pour-in-place surfacing utilize recycled rubber in their shock pads that are installed below the EPDM color granules. American Surface Technologies, based in Scottsdale, Arizona, offers a pour-in-place that is made from 100% recycled SBR rubber. Though the initial cost of installing unitary synthetic materials is relatively high, rubber products and pour-in-place surfacing require minimal maintenance and offer consistent shock absorbency because they are not displaced by kids during play. The National Program for Playground Safety (NPPS), a non-profit organization based at the University of Northern Iowa and funded by the CDC, recently completed a two-year study of the safety of the nation's playgrounds. As part of this study, the group graded all 50 states on safety surfacing. The results offered some good and bad news about our nation's parks. The good news is that 78 percent of U.S. playgrounds have suitable surfacing. The bad news is that only 47 percent of the playgrounds have these materials at the appropriate depth that would adequately cushion a fall. Additional data regarding this subject is expected in the year 2000. To stay up-to-date, check out the NPPS website at www.uni.edu/playground. The challenge for a Landscape Architect is to create a play environment that not only captures the creativity and spontaneity of a child but also meets all the required safety standards. If the play elements don't entice a child and keep their attention then the child is likely to make it challenging in ways that the designer never intended. For example, on a low platform with a barrier, a child who is looking for more excitement will probably climb over the barrier and walk around the outside.