Frequently Asked Questions on the Development of a Field Test Method for Measuring the Firmness and Stability of Surface Systems
Prepared by the National Center on Accessibility
In 2005, a task group within the American Society of Testing and Materials (ASTM) F08.63 Subcommittee on Playground Surfaces began working on the development of a test method to objectively measure firmness and stability of surfaces systems as related to accessible routes on playgrounds. This test method can be used by playground owners, facility managers and others as a method for measuring firmness and stability of surfaces. The following FAQ’s have been prepared by the National Center on Accessibility to provide background information to playground owners, recreation practitioners, and others about the field test method for measuring surface firmness and stability.
The rotational penetrometer is a portable field test designed to measure surface firmness and stability. The rotational penetrometer consist of two identical, symmetrical surface reference plates, a frame, and a penetrator assembly incorporating a wheel or caster assembly and a means of applying a load to the penetrator. The two surface reference plates contact the surface and distribute the weight of the operator. The penetrator rotates about a vertical axis relative to the surface reference plates allowing for measurement of firmness and stability of the surface. Two types of measurements are taken with the device. The first measures the initial penetration into the surface, the firmness reading. From that point, the wheel or caster is moved back and forth four times and device gives the second measure of displacement into the surface for stability.
2. Why a test method for surface “firmness” and “stability”?
Accessibility standards such as the Americans with Disabilities Act Accessibility Guidelines (ADAAG, 1991, revised 1994), the Uniform Federal Accessibility Standards (1984) and the Architectural Barriers Act Accessibility Standards (ABAAS, update effective 2006) include a technical provision that requires the surface of accessible routes, clear spaces, and turning spaces serving people with disabilities be “firm and stable.” This language dates back to the 1960s and A117.1 Accessible and Usable Buildings and Facilities, the first nationally recognized technical provisions addressing accessibility in public spaces, developed by the American National Standards Institute (ANSI). A definitive performance measure provides information about the level of surface “firmness and stability.”
3. What other tests have been used to measure surface “firmness and stability”?
A laboratory test using the “wheelchair work method” was developed in 1999 to measure playground surfaces. This is standard is known as ASTM F1951-99 Standard Specification for Determination of Accessibility of Surface Systems Under and Around Playground Equipment, the first attempt to provide more objective criteria for measuring “firmness and stability” of surface materials. ASTM F1951-99 measures the work required to traverse a surface during a straight propulsion in wheelchair and during a 90 degree turn.
|Straight propulsion test.||90 degree turn test.|
4. How would surface “firmness and stability” be determined if a complaint is filed under the ADA or the ABA?
Without a referenced test method, “what” constitutes “firm and stable,” will continue to be determined by the courts, individual investigators from federal offices of civil rights, and through private rights of action where settlement agreements have negotiated corrective actions to make surfaces on accessible routes more usable for people with disabilities. Through subjective inspection, summary judgment or settlement, woodchip (City of Green Bay Parks and Recreation Department, 1993; San Francisco Unified School District, 1995; Mt Diablo Unified School District, 1998-2007;), pea gravel (U.S. Department of Interior National Park Service Office of Civil Rights, 1999), sand (City of Weston, 2008) and other outdoor surface materials have been found to be not firm or stable for use on the accessible route. No quantifiable data on the firmness and stability characteristics of these surfaces exists. Without a field test method to objectively determine the firmness and stability of various surface materials, the accessibility of every surface material will be left to the courts to decide.
Currently, the proposed test method put forth by the ASTM task group does not include performance criteria for any type of surface or surface system. Performance criteria can be established by organizations referencing the test method for specific types of surfaces or surface systems and the environment they are installed.
No. There is no approval process under the ADA and never has been. Information test results for ASTM F1951-99 regarding specific surfaces could assist a playground owner looking to purchase a surface for a play area required to be accessible.* After purchase and installation, the playground owner is required to ensure that the surface is maintained and inspected frequently to continue to meet the specifications.
*The ADA does not cover play areas located in private residential or religious entities.
A baseline measurement should always be taken on a concrete or asphalt surface. This measurement should always be consistent +/- .02 inches based on the latest calibration of the device. The measurements taken on various surfaces are dependent on the type of surface material that is being tested. If the surface is a highly variable material, there will be a greater standard deviation based on the characteristics of the surface material.