1.1 This practice covers the determination of shock-attenuation characteristics of natural turfgrass thoroughbred horse-racing surface systems using lightweight portable apparatus. This practice is applicable for comparing natural surfaces and assessing the effects of management practices on shock attenuation. This practice also can be used to assess the compactibility of natural surfaces by recording Gmax values, penetration of successive impacts, conversion/computation of CBR values, or any combination or all. 1.2 This practice provides a procedure for assessing impact characteristics in the field, on actual playing surfaces, and on research plots using Test Method F1702. Numerical data will not be comparable to data obtained using a different missile mass or geometry, a different drop height, or a different standard method, for example, Test Method F355. 1.3 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only. 1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
In the late 1980s and early 1990s, a set of Clegg impact value interpretations were developed and proposed in a combined program between Texas A&M University (TAMU) and Santa Anita Park. Although initially published in some trade magazines (landscape), these guidelines were not widely distributed in any type of official or standardized manner. Over the years, the practice of using a lightweight portable impact analyzer for turf track evaluation has become routine and the interpretation of the value ranges from that originally proposed by TAMU/Santa Anita has changed. This standard proposes to formalize the practice of these impact evaluations (using the method of F1702) and the interpretation of the results. The purpose for these evaluations is not to assess or assign any type of race condition (condition being a specialized term used in the racing industry) but rather to assess the timing or need for certain turf maintenance or management practices. These practices may include such things as irrigation timing/duration (or differential sequencing), mechanical aeration practices (such as coring, spiking, slicing, shatttering, and so forth), thatch control (fertilization, mowing, scalping, verticutting, and so forth), or other practices. Impact evaluations may also be used to assess the effectiveness of any of the above practices that may have recently been completed. As well as the direct evaluation of impact characteristics at any particular location (or within a running lane), the uniformity of these impact properties throughout the racing surface is an important evaluation factor. Sudden or drastic changes in racing surface characteristics are often cited as safety hazards in the horse-racing industry.
KeywordsClegg tester; Gmax; impact soil tester; impact test hammer; impact value; natural turf; thoroughbred racing; horse race track; playing surface; shock attenuation; soil; turfgrass
The title and scope are in draft form and are under development within this ASTM Committee.Back to Top
Draft Under Development