Playground Advisory

4 tion to each other. Loose materials are generally installed in such a manner as to continuously absorb impact through the resistive moving of particles away from the force of the im- pact and this is repeatable in the playground when the sur- face materials have sufficient depth to resist excessive dis- placement and disruption. Synthetic surfaces rely on a binder to hold the particles together as in poured-In-place or mats, while other systems such as synthetic turf rely on the carpet pile to stabilize the loose fill particle, and the underlying bonded particles of foam move in relation to each other. How this movement is performed on a consistent basis will determine the impact attenuating properties of the surface. The ability of the particles to remain in place over time, con- tinuing to provide the intended impact attenuation will deter- mine the value of the surface as a viable system. Temperature has a bearing on how these products perform and ASTM F1292 requires that surfaces systems be tested at 24F, 72F and 120F to demonstrate that they are suited to the range of temperatures children will play in. F1292 recom- mends that if the surface is to be installed outside the tested temperature range or in frozen conditions, tests should be conducted under those conditions to determine suitability to a particular environment. The recognition of the actual in- stalled environment being a factor is further recognized with testing in the field to F1292. These tests are performed in the conditions and ambient temperature that the surface is found and air and surface temperatures and other weather conditions are recorded. Failure of this test in the field re- sults in the play structure related to the failed surface being taken out of service until the surface complies. The ASTM F1292 laboratory testing was established to allow comparative examination of surfacing materials and to allow manufacture to test uniform samples to a uniform procedure. From a practical point of view there are shortcomings to the laboratory testing. It must be remember that sample size for the laboratory testing for ASTM F1292 is a box that is 18”x 18”. For syn- thetic systems the box structure can be left in place or re- moved as the rigid box side should not have an influence on the result. Alternatively for loose materials, the box sides cannot be removed and do not allow for the displacement of the materials sideways nor does it indicate how this surface will perform in traffic areas in the actual playground. As a result a test report for loose fill that provides excellent test results in a laboratory condition should not assure the own- er/operator of continued “safe” performance in the field. Factors not taken into consideration in F1292 are contamina- tion during use or the aging of the surface under outdoor con- ditions. Many aggregate loose fill systems when abraded against their adjoining particles will breakdown and the dust will fill the void space that was originally there, with a resulting loss of attenuating features. This contamination causes many of these surfaces to fail the impact requirements. Although only mineral aggregates will be subject to this type of contami- nation, every material will be subject to contaminants that can be set between the systems particles. A peculiarity of wood chip systems is that when these products abrade and form sawdust, there is a tendency for the surface to have better impact attenuating properties. As a result each system must be review as to its performance during active use over 12 to 25 years. Loss of depth through wind, rain, attrition or removal from the playspace is also not predicted by the results of ASTM F1292. It is for this reason that standards such as the CSA Z614 recom- mend the installation of a minimum of 12” of loose materials to allow for disruption over time. ASTM F1292 laboratory testing is performed on new samples and there is no consideration of aging or weathering. Many bound rubber systems utilize a polymer binder that is not UV stable and these system tend to get more ridged over time. Given that almost every playground is outdoors, this potential for failure is a major problem for the owner/operator. Failure of these systems generally results in a complete replacement. Poured-in-Place surfacing systems are actually the subject of a guide standard, ASTM F2479. This standard recognizes that there are choices in binders; the non UV stable and low cost aromatic binders and the UV stable and higher cost aliphatic binders. The choice of binder is made generally on a cost vs. longer term conformance to the ASTM F1292 for the installed