13 The RP design includes a wheelchair caster placed on a spring loaded caliber in a metal tripod frame which suspends the caster about 6 inches over the surface. When the caster is released, the spring load gauge replicates the force of an individual in a wheelchair over a given surface. The penetraƟ on into the surfaces is measured for readings of “fi rmness” and “stability.” NaƟ onal experts recognize the use of the RotaƟ onal Penetrometer as a portable and relaƟ vely easy device to use for surface tesƟ ng. The fi eld test method with the RP can be added to the assessment process just as measurements for slope, cross slope, change in level and openings are taken along segments of the accessible route for the play area. The RP can measure those segments for fi rmness and stability. This can be valuable in assessing how an installed surface performs over Ɵ me. Impact AƩ enuaƟ on: Lab & Field Test In the fi eld, ASTM F1292-99/04 Standard Specifi caƟ on for Impact AƩ enuaƟ on of Surface Systems Under and Around Playground Equipment is also known as the “head drop test.” It is a test to make sure the surface is resilient enough to prevent a lifethreatening injury from a fall. A 6 inch diameter aluminum hemisphere in the shape of a child’s head is dropped from the top of a tripod based on the fall height of play components. The aluminum hemisphere, or missile as it is called, contains an accelerometer. When dropped, the impact aƩ enuaƟ on of the surface is measured in G-max and by the Head Injury Criteria (HIC). G-max is a measurement of the maximum acceleraƟ on, while HIC measures an integral of the acceleraƟ on Ɵ me. The maximum values allowable by the standard are 200 for G-max and 1,000 for HIC. A TRIAX is the instrument used to conduct this test in the fi eld. Playground Owners Can UƟ lize Field TesƟ ng to Get the Most Out of Their Surface InstallaƟ on The NCA surface study found the need to conduct fi eld tesƟ ng immediately following installaƟ on and throughout the life of the playground surface is criƟ cal to insure compliance with ASTM F1292-99/04 and ASTM F1951-99. A surface locaƟ on can appear to be very accessible by the “look” of it. However, results may be surprising when the surface is actually fi eld tested. This point is illustrated at NCA study sites managed by two diff erent agencies. One of the parƟ cipaƟ ng municipaliƟ es manages more than 30 park playgrounds, predominately surfaced with engineered wood fi ber (EWF). The park maintenance personnel usually install the EWF by raking it level, allowing it to seƩ le over Ɵ me and topping off seasonally. The research team found the results for fi rmness and stability were not consistent with the manufacturer’s ASTM F195199 results. The inconsistency was found in the installaƟ on process. The research team informed the playground owner of the fi eld test results. Then the park maintenance crew changed their procedure for installaƟ on and also began compacƟ ng the surface material when it was topped off . Subsequent fi eld tesƟ ng yielded much beƩ er results for fi rmness and stability. Another playground owner opted to also have the surface tested for impact aƩ enuaƟ on and compliance with ASTM F1292. Drop heights from composite equipment up to 8 Ō . high passed the fi eld test. But it was the poured in place (PIP) surface at two swing bays that was found in non-compliance with HIC scores well over the 1,000 HIC allowable under the standard. The playground owner used the terms of the warranty and purchase order as a binding agreement requiring the manufacturer, at its own expense, to return to the site and repair the surface installaƟ on. Approximately 2,000 sq. Ō . at the swing bays was resurfaced to add more depth to the PIP. When the surface area was retested, the HIC ranged from 650-750 at the swings, well under the 1,000 maximum allowable by the standard. Had the playground owner not discovered the non-compliant surface area unƟ l aŌ er the warranty had expired, it would have cost the agency in excess of $35,000 to correct the surface area serving four swings. During the course of the longitudinal study, at least two addiƟ onal playgrounds surfaced with PIP were found in non-compliance with ASTM F1292. In each case, the playground owners required the installers to return to the site to make correcƟ ve acƟ ons. The only way to verify the surface is installed similar to that in which it passed the laboratory test is to conduct fi eld tesƟ ng. A TRIAX is used here to test impact aƩ enuaƟ on or the play surface’s ability to absorb a fall and reduce severity of injury.
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