Grasspave2 by Invisible Structures Inc. has become the first grass porous paving surface to meet maneuverability requirements as an Americans with Disabilities Act (ADA) accessible surface for handicap and wheelchair access. Sites can now meet “green space" requirements and ADA requirements in the same multi-use space.
Porous paving is quickly becoming the most suitable alternative for traditional paving of concrete and asphalt. The environmentally preferred choice, porous paving systems like Grasspave2 and Gravelpave2 (gravel containment porous paver) are based on simple but impressive technology; the structure is designed to withstand significant structural loads and also provide stability, flexibility and porosity.
The ADA requires that all public playgrounds and beaches be made accessible to America’s 43 million disabled. Invisible Structures’ product line makes it easy and cost-effective to comply with the law. ADA-compliant surfaces can be implemented on almost every inch of developed land while enhancing the environment.
While there is no blanket testing for ADA accessibility requirements, the U.S. Department of Justice’s “ADA Standards for Accessible Design” and ADA accessibility guidelines currently specify that surfaces that are required to be accessible must be “stable, firm and slip-resistant." A stable surface is defined as the degree to which a surface resists change from contaminants or applied force, so that when the contaminant or force is removed, the surface returns to its original condition. The firmness of a paved surface is the degree of surface resistance to deformation, especially by indentation or the movement of objects. The slip-resistance of a surface is the degree to which a surface provides frictional counterforce to the forces exerted in walking to permit safe ambulation.
Invisible Structures chose to perform the only available surfacing tests to ensure that a Grasspave2 surface meets these conditions. Grasspave2 is a stable and moderately firm surface; its unique sand fill, ring structure and grass position make it the only grass paver to have passed any testing. Invisible Structures enlisted Beneficial Designs Inc. for independent testing of the installed Grasspave2 surface. Grasspave2 met the maneuverability performance requirements of ASTM F 1951-08 for determination of accessibility of surface systems under and around playground equipment. There was also an additional test preformed, the Rotational Penetrometer Surface Testing Report, which gives results on firmness and stability. The Grasspave2 tested was placed over a 6.75-in. minus base course material compacted to 95 percent modified proctor density. The Grasspave2 rings were filled with concrete sand and then topped with a “washed” sod (.25-in. soil).
The ASTM test consisted of measuring the amount of work it takes to maneuver a wheelchair turning and in a straight line over Grasspave2. The results are compared with testing on a 7-percent ramp that is not a Grasspave2 surface. Essentially, if the Grasspave2 surface is less work to maneuver over than on the slope, it passes the test. The Rotational Penetrometer measures properties of the surface of the Grasspave2 via a wheel and gauges. The properties are compared to known surfaces and given a rating.
Grasspave2 now joins Gravelpapve2, also tested by Beneficial Designs in 1999, and Beachrings2 as ADA accessible surfaces manufactured by Invisible Structures Inc.
