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

II. Research Methodology

The research design for this study of playground surfaces has been in development since 2005 with input from a national advisory committee.  It is purposeful to derive quantitative and qualitative data through on-site inspections for a 3‒5 year period.  Advisory committee members represented the U.S. Access Board; the National Playground Safety Institute; Beneficial Designs; Northern Suburban Special Recreation Association; Bloomington (IN) Parks and Recreation Department; and the American Society for Testing and Materials.  Periodic meetings and conference calls were held to review the research design. The advisory committee members provided feedback on the categories of surfaces to be evaluated, the criteria to be used for evaluation, the locations within each playground to be evaluated, data collection worksheets and on-site protocol.  In addition, advisory committee members helped to expand the network for recruitment in the study and increase national awareness among playground owners.

Study Questions

The purpose of this study was to evaluate a variety of playground surfaces, their ability to meet accessibility requirement, their costs upon initial installation and maintenance issues over a 3‒5 year period.  The research questions include:

1. How well do various playground surfaces meet the accessibility requirements upon installation and over a five-year period?

2. What are the costs for the various playground surfaces?

3. What accessibility issues arise out of initial installation?

4. What accessibility issues arise out of long term use and require additional maintenance?

Selection of Playgrounds

Newly constructed public playgrounds were selected for participation as test sites in the study.  A purposive snowball sampling technique was used to recruit local park and recreation agencies by phone, e-mail and in person.  This sampling technique utilizes acquaintances and word of mouth referrals so the sample grows or rolls larger like a snowball.  The sampling technique is largely dependent on informed participants passing information on to other perspective participants.  Selection was based upon: accessibility to children with and without disabilities; use of surface materials and products consistent with the study; geographic location; seasonal weather conditions; and willingness of owner/operator to participate as a partner in the study by sharing information and collecting data.   The study is limited to the geographic area surrounding the Indiana University-Bloomington campus, Indianapolis and Chicago, within driving distance of the Bloomington-based research team and easily accessed at any given time during the season.  The geographic area also supports a close network of practitioners in the field from which test sites could be recruited. 

The sample population for this study depended upon an established, or to be established, congenial relationship with the playground owner and the research team.  The data for analysis required the research team to make a number of inquiries to the operation, planning, budgeting and maintenance procedures conducted by the playground owner.  Most importantly, if there were any instances where locations on the playground were found to be in non-compliance with the accessibility or safety guidelines, the playground owner was to be informed and then carried the burden of bringing those instances into compliance.  Therefore an established relationship based on trust and mutual concern for safety, accessibility and the research questions was necessary.

Streeton, Cooke and Campbell (2004) summarized the advantage to the snowball sampling technique as an efficient way to locate hard-to-reach groups, especially when using a named contact to open doors otherwise apparently closed.  Gruppetta (n.d.) summarized the positive aspects of snowball recruitment as reaching a wider range of participants; reduced possibility of coercion by the researcher; sensitive data is not yet made available to the researcher; a reduction of researcher bias; informal networks of communication; and cost effective.  Alternatively, the negative aspects of snowball sampling are viewed as labor intensive; inappropriate for a probability sample; raising ethical considerations for the protection of privacy; concerns for the timeliness of the process; perceived coercion for the nominee; inability to select participants; and multiple nominations within the group that may narrow rather than open the pool of perspective participants (Gruppetta, n.d.; Streeton, et. al. 2004.).  The depth of qualitative data for analysis forecasted to derive from the longitudinal study can be argued as outweighing the negative aspects of this particular sampling technique.

Limitations

The study is limited in the following ways:

1. Ability to generalize findings to the general population.  Playgrounds are as different as children, each with their own distinguishing personality.  Each one is very different in terms of design, frequency of use, the combination of playground equipment, surface materials, soil characteristics, site conditions, weather and climate.

2. Visitor use may have impact on the surface conditions.  It is impossible to control the number of children using any given public playground.  High visitor use may have an effect on certain surface types.

3. Weather conditions, adverse seasonal changes, sunlight and precipitation may have an effect on certain surface types.

4. Liability associated with sites found to be non-compliant with the standards may affect a playground owner’s willingness to participate in the study.

Assumptions

Two industry standard specifications are used to determine the safety and accessibility of each surface: ASTM F1292‒99/04 Standard Specification for Impact Attenuation of Surface Systems Under and Around Playground Equipment and ASTM F1951‒99 Standard Specification for Determination of Accessibility of Surface Systems Under and Around Playground Equipment.  Both specifications are written as laboratory tests.  For the purpose of this study, it was assumed that:

1. Playground surfaces selected for participation have documents indicating they have met the minimum specifications for ASTM F1292‒99/04 and ASTM F1951‒99 in a laboratory environment.

2. A Rotational Penetrometer can be used as a field instrument to determine firmness and stability for surfaces as they relate to accessibility.

3. A TRIAX 2000 can be used as a field instrument to determine impact attenuation.

4. Playground owners will be notified of evaluation results upon inspection and be given the opportunity to take corrective actions.

Definition of Terms

For the purposes of this study and further discussion, the following terms will be used:

Accessible.  The element or feature meets the minimum technical specifications under the 2010 Americans with Disabilities Act (ADA) Standards for Accessible Design and the Architectural Barriers Act (ABA) Accessibility Standards.

Firmness or Firm Surface.   A firm surface resists deformation by either indentations or particles moving on its surface (2010 ADA Standards for Accessible Design, Advisory 302.1). 

Loose Fill Surfaces.  The predominant surface characteristic is one where many loose particles are combined to create the surface system.  Loose fill surfaces may include gravel, pea gravel, sand, wood chips, mulch, engineered wood fiber and shredded rubber.

Rotational Penetrometer.  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 penetration into the surface is measured for readings of “firmness” and “stability” of the surface. 

Stability or Stable Surface.  A stable surface is one that remains unchanged by contaminants or applied force, so that when the contaminant or force is removed, the surface returns to its original condition (2010 ADA Standards for Accessible Design, Advisory 302.1). 

Triax 2000.  A large tripod that can be raised to a fall height above the highest play surface on a playground.  A large sphere replicating the shape of a child’s head is dropped from the top of the tripod and the impact on the surface is measured.  A Triax is the instrument used to test playground surfaces for compliance with ASTM F1292‒99/04, also known as the “head drop test.”

Unitary Surfaces.  The predominant surface characteristic is whole.  Unitary surfaces may include asphalt, concrete, rubber mats, tiles or a rubber fill product chemically bound and often referred to as “poured-in-place.” 

Data Collection Procedures

Each playground owner identified a minimum of one newly constructed or planned playground using at least one surface material in the designated categories of study surfaces.  The playground owners hosted the playground test sites and assisted with data collection for the study.  Playground sites were limited to public playgrounds owned and/or operated by municipal parks and recreation agencies.  The name and location of the playground sites were kept confidential and only broadly labeled by county/region during comparisons to other playground sites.

Upon consent to participate in this study, the playground owner was asked to designate a site coordinator (study liaison) to work with the research team.  This individual was responsible for assisting with collecting data during the initial site visit and continued to work with NCA throughout the duration of the longitudinal study.  It was preferred, but not necessary, that the designated staff representative was a Certified Playground Safety Inspector (CPSI) or Accessibility Coordinator.  In the event any non-compliance issues were identified on site, the designee could easily be alerted and initiate the agency process for maintenance or other corrective actions. 

Once brought into the study, the playground was associated with one of five categories of surface type for participation in the study:

1.         Engineered wood fiber product;

2.         Shredded rubber/crumb rubber;

3.         Unitary rubber mat/tile surfaces;

4.         Unitary rubber “poured in place” surfaces;

5.         Combination or hybrid surface systems under development.

The playground surface products considered for this study had to initially meet the requirements of the 2010 Americans with Disabilities Act (ADA) Standards for Accessible Design and the Architectural Barriers Act (ABA) Accessibility Standards: 1008.2 Accessible Routes; 1008.2.6 Ground Surfaces; ASTM F1292‒99/04 Standard Specification for Impact Attenuation of Surface Systems Under and Around Playground Equipment as determined by the surface manufacturer in laboratory testing; ASTM F1951‒99 Standard Specification for Determination of Accessibility of Surface Systems Under and Around Playground Equipment as determined by the surface manufacturer in laboratory testing.  Information on the surface vendor, specifications, costs and labor for installation was then collected.  In turn, the research team contacted each vendor to collect additional information on laboratory certification with ASTM F1951‒99. 

Nine critical areas were inspected within 12 months of installation and continue to be evaluated at least once a year for the longitudinal study:

1. Entry to playground where playground surface starts

2. Accessible route connecting accessible play elements

3. Egress point of slide(s)

4. Swings

5. Entry point(s) to composite structure(s)/transfer stations

6. Climber(s)

7. Ground level play element(s) such as spring rockers, play tables, interactive panels, etc

8. Sliding poles

9. Other areas (i.e. water play elements, etc)

Using the playground site plan and/or digital images, the research team and site coordinator identified the nine critical areas for data collection.  Within 12 months of installation, the research team and site coordinator conducted a preliminary accessibility assessment of the playground surface and tested the surface for firmness and stability with the Rotational Penetrometer.  This was considered the first site visit for the longitudinal study.  On-site assessments continued annually throughout the longitudinal study.  At the discretion of the playground owner, the playground surface was also tested for impact attenuation with the TRIAX (surface impact testing device).  The playground owner was notified immediately of test results for both the Rotational Penetrometer (firmness/stability) and the TRIAX (impact attenuation) and given opportunity to correct surfaces where deficiencies or non-compliance with standards were noted.

Instrumentation for Analysis

Four instruments were used for data collection.  First the owner was sent information sheet on the protocol for the study (Appendix A).  Upon installation, the playground owner completed a questionnaire (Appendix B) on the type, size and intended age group of the playground, the total cost for the equipment, surface materials and installation.  An on-site inspection form (Appendix C) was created to collect information on the nine locations identifying deficiencies in slope, cross slope, changes in level and openings in the surface.  Following the visual inspection of the nine locations, testing for wheelchair accessibility specific to firmness and stability was conducted with the application of a Rotational Penetrometer (RP).  A third form was developed to collect data on firmness and stability (Appendix D).  Testing for impact attenuation per ASTM F1292‒99/04 was conducted as an optional test at the discretion of the playground owner using the TRIAX 2000.  This data was reported to the playground owner in the format prescribed by the ASTM F1292‒99/04 test protocol.

Treatment of Data

The research design for this study was developed to collect data on surface conditions, evaluate surface performance, note deficiencies and compare results across surface types.  Through further analysis, results of playground surface tests for firmness and stability were compared within surface categories and across surface categories to determine the mean, range and standard deviation of each surface type.  Finally, data on initial installations costs and results of surface tests on firmness and stability were compared to determine whether there was correlation between the surface type, its costs and its results for firmness and stability.  Descriptive statistics were used for analysis of data.  A one-way analysis of variance (ANOVA) was used to determine if there was any statistical significance between surface categories.  A bivariate correlation was run to determine any significance between surface deficiencies or non-compliance with the accessibility standards and the measurable results for firmness and stability.  Lastly, qualitative data on the surface material conditions during the site visit was collected in order to provide a narrative description of findings.