Summary Characteristics of Organic and Inorganic Loose-Fill Materials, and Unitary Synthetic Materials ORGANIC LOOSE MATERIAL wood chips, bark mulch, engineered wood fibers, etc. Fall Absorbing Characteristics Cushioning effect depends on air trapped within and between individual particles, and pre-supposes an adequate depth of material. Installation/Maintenance Should not be installed over existing hard surfaces (e.g., asphalt, concrete). Requires a method of containment (e.g., retaining barrier, excavated pit). Requires good drainage underneath material. Requires periodic renewal or replacement and continuous maintenance (e.g., leveling, grading, sifting, raking) to maintain appropriate depth and remove foreign matter. Advantages Low initial cost. Ease of installation. Good drainage. Less abrasive than sand. Less attractive to cats and dogs (compared to sand). Attractive appearance. Readily available. Disadvantages The following conditions may reduce cushioning potential: Rainy weather, high humidity, freezing temperatures. With normal use over time, combines with dirt and other foreign materials. Over time, decomposes, is pulverized, and compacts requiring replenishment. Depth may be reduced by displacement due to children's activities or by material being blown by wind. Can be blown or thrown into children's eyes. Subject to microbial growth when wet. Conceals animal excrement and trash (e.g., broken glass, nails, pencils, and other sharp objects that can cause cut and puncture wounds). Spreads easily outside of containment area. Can be flammable. Subject to theft by neighborhood residents for use as mulch. |
