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Discuss Impact Performance of Playground Surfaces on November 8

On Fri., Nov. 8, at 8 a.m. in Miami Beach, ASTM Subcommittee F08.63 on Playground Surfacing Systems will discuss revisions to a 1999 specification that evaluates impact performance of playground surfaces.

The subcommittee invites stakeholders to participate in the proposed revision of ASTM F 1292, Standard Specification for Impact Attenuation of Surface Systems Under and Around Playground Equipment. Proposed revisions address an improved precision test for the impact performance of all types of playground-surface materials, based on new research by the task group of scientists, consultants, manufacturers, and a member of the U.S. Consumer Product Safety Commission. Contact chairman Martyn R. Shorten, Ph.D., listed below, to review the draft revision. ASTM membership is not required for this activity within ASTM Committee F08 on Sports Equipment and Facilities.

“These suggested revisions represent major steps toward a repeatable and reproducible test method that will better serve the nation’s children and the playground industry,” says Shorten, a biomechanist and managing partner for BioMechanica, LLC, Portland, Ore. “Any actual changes to the standard will require a much broader consensus, of course, and we look forward to debating these ideas in the ASTM forum.”

The task group drafted the following revisions which are open for discussion:

General

1. A general reorganization of the standard in order to consolidate repeated elements and to make it more user-friendly.
2. Editing for clarity and consistency of terminology.
3. Clarification of the scope and purpose of the standard.
4. Incorporation into the standard of relevant elements of ASTM F 355 so that the document stands independent of F 355.
5. Correction and clarification of the terminology defined in the standard.

Performance Criteria

6. Eliminate the HIC requirement. [Head injury criteria (HIC) defined in Standard F 1292 is a measure of impact severity that considers the duration over which the most critical section of the deceleration pulse persists as well as the peak level of that deceleration.]
7. The HIC calculation amplifies measurement errors and is an inherently less reliable measure than gmax. Also, it is questionable whether HIC is even a valid measure when rigid headforms are used.
8. Reduce the gmax limit to 150 g.
9. Accumulated test data from unitary and loose fill surfaces shows a curvilinear relationship between gmax and HIC scores. On average, a gmax score of 150 is equivalent to a HIC score of 1000. Therefore, if the HIC criterion is eliminated, and the gmax limit is reduced to 150g, the effective performance requirement will remain very similar to the existing one, but the precision of the test method will be considerably improved.

Test Method

10. Consolidation of field and laboratory test methods into a single method.
11. In the context of the single method, define sub-protocols based on the primary method for unitary and loose fill surfaces and for laboratory and field tests.
12. More specific requirements for the preparation and compaction of loose-fill materials.
13. Modification of temperature conditioning requirements to ensure that the second and third drops of “cold” and “hot” tests do not diverge excessively from the target temperatures.
14. Additional protocols for performing tests on “wet” and/or “frozen”surfaces.
15. Specification of a single headform for all F 1292 tests. Currently, two headforms with different masses and shapes are specified. Since the ANSI “C” headform has been found to produce more variable results, the subcommittee will propose that a hemispherical headform be used.
16. A requirement that a triaxial ac celerometer will be required for laboratory tests, as well as field tests.
17. A requirement that an MEP calibration pad be used to check and adjust test scores.

Equipment and Signal Conditioning

18. More stringent sensitivity and accu racy requirements for accelerometers.
19. More detailed specifications for signal conditioning and filtering. (Differences in signal conditioning have
been identified as a source of variability among laboratories.)
20. A requirement that manufacturers of equipment and laboratories who make their own equipment perform certain validation tests on test apparatus to ensure that signal conditioning, filtering and data processing systems perform within specified tolerances.
21. A requirement that laboratories performing certification tests maintain a record of the validation tests.

Precision and Bias

22. A new ILS is proposed. The ILS will be performed using MEP pads and the measured outcome will be critical fall height.
23. Document the variability of typical surfaces separately from the precision of the test method itself. The current precision statement includes the variability of surfaces as well as that of the test method.

Annexes and Appendices

24. Incorporate information from Annex on Field Testing into the body of the standard
25. Expand the information on data acquisition and signal conditioning to provide more specific guidance and recommendations.
26. Add instruction on procedures for verifying the performance of data acquisition and signal conditioning systems.
27. IF HIC remains a performance criterion, replace the computer program with a simpler, more accurate one.

The task group welcomes comments and will include feedback in the proposal they submit to ASTM for ballot. Individuals wishing to participate should contact Martyn R. Shorten, Ph.D., BioMechanica, LLC., Portland, Ore. (phone: 503/452-0350). Committee F08 meets Nov. 6-9 in Miami and May 7-10 in Kansas City, Mo. For membership or meeting details, contact Jim Olshefsky, director, Committee Services, ASTM International (phone: 610/832-9714). //

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