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

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.”