A Longitudinal Study of Playground Surfaces to Evaluate Accessibility - Final Report

Implications

The qualitative data from the on-site inspections support the perceived advantages and disadvantages of the unitary and loose fill materials as described in the literature review.  The initiation of the surface deficiency score can quantify where the surface samples fail to comply with the standards for slope, cross slope, vertical change in level, or openings in the surface.  Further, the measurement of firmness and stability can serve as an indicator of the variable characteristic of the surface sample. 

Lack of playground sites with shredded rubber for participation in the study prohibited collection of quantitative and qualitative data regarding the accessibility of this loose fill surface material.  The recycled shredded rubber industry, over the last five to eight years, has positioned itself as the provider of a “green,” environmentally friendly product that is safe and accessible.  As such, there is a marked absence of public data as to how this particular type of surface material would compare to PIP, TIL, EWF and HYB.  Comparison of shredded rubber with the only other loose fill surface material in the study, EWF, could not be made.  There are no data to show how the two surface materials compare to one another or how the two surface materials in the category of loose fill would compare to the category of unitary surface material. Without descriptive statistical analysis of the firmness and stability of shredded rubber as a playground surface, playground operators do not know how the material will perform over time in the field.

Proper installation in accordance to the manufacturer’s instructions, per the standards, and by experienced personnel is critical.  Sites where the various surface materials have been installed by park personnel with limited experience on the installation procedures, ASTM specifications, and accessibility standards were reported with deficiencies within 12 months of installation.  It is critical for the installation crew to fully understand and adhere to the manufacturer’s instructions, less the terms of the warranty be rendered null and void.

Visual inspection alone cannot determine if the playground surface is accessible and impact attenuating in accordance with the ASTM standards.  The discovery of areas in the sample where the surface was found in non-compliance for ASTM F1292‒99/04 impact attenuation was alarming for both the research team and the playground owner based on the beautiful appearance of the newly installed surface, the cost for the surface and the assumption that it was installed with the specific intent of minimizing injury for children using the play equipment.  A playground surface may have few to no identifiable deficiencies specific to the accessibility of the route, however, this does not have any relation to whether the surface has the ability to absorb the impact from a child’s fall per the safety standards.  Field tests for compliance with ASTM F1292‒99/04 must be conducted following installation and be part of an ongoing maintenance routine to ensure the integrity of the safety resilient surface system. 

There needs to be a portable field instrument to determine compliance for ASTM F1951‒99.  The current test protocol is designed for a laboratory environment and the cost for the equipment to measure the work force of the manual wheelchair moving across the surface is upward of $20,000.  The cost is prohibitive to playground owners and contractors that need to confirm the surface material has been properly installed and maintained to the same specifications the sample was tested and certified to ASTM 1951‒99 in the lab.  For the purpose of this study, the Rotational Penetrometer was used as the field instrument to measure firmness and stability in lieu of the costly equipment for ASTM F1951‒99.  Documented research has shown the Rotational Penetrometer to have a high degree of repeatability and reproducibility (ASTM, May 27, 2005; ASTM, September 2010). ¹

PIP and EWF represent the most diverse characteristics of each category in this study.  Findings from this study provide expanded knowledge on the objective measurement of firmness and stability along with the variability of the material characteristics contributing to the accessibility of the surface.  The measured values for firmness and stability, standard deviation and the sum of the values illustrate the variability of the material characteristics and composition.  If manufacturers reported the average values for firmness and stability, similar to the ASTM requirement to provide laboratory test results for the critical fall heights of the surface sample, playground owners could gain a better understanding of the variability of the surface material and select a surface material more appropriate to their agency resources for installation and long-term maintenance.  However, again, to ensure consistency, repeatability and reproducibility, an ASTM field test protocol is critical.  Published information on the correlation between the surface material’s firmness and stability in relation to the frequency of non-compliance with the accessibility standards for running slope, cross slope, changes in level and openings, could create a greater awareness among playground owners and positively influence their purchasing decisions and maintenance practices.  If the playground owner had a better understanding of the values measured with the Rotational Penetrometer, they might also be better equipped to establish an installation baseline and maintenance targets for the surface material.

Data on the performance of the hybrid surface systems may be promising enough to lead to further research and product development as the next generation of accessible protective playground surfacing.  Although, much more research needs to be conducted among all three brands of hybrid surfaces in this study to evaluate the longevity for impact attenuation, durability for high public use, resistance to vandalism, and ability to withstand various outdoor climates.  Product development in this category of hybrid surface systems, where there is some type of loose fill base covered by a unitary mat, could eventually provide a more middle ground in terms of costs and overall performance if the data on longevity and durability are made available up front for the playground owner prior to the decision to purchase.

¹ Results of interlab studies determining the repeatability and reproducibility of the Rotational Penetrometer were reported through work items of the ASTM F08.63 Subcommittee on Playground Surfaces.  For more information, contact ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA, 19428-2959.