ASTM D 6393/D 6393M:2025

1.1 This test method covers an apparatus and procedures for measuring properties of bulk solids, henceforth referred to as Carr Indices. 2 1.2 This test method is suitable for free flowing and moderately cohesive powders and granular materials up to 2.0 mm [¹/₁₆ in.] in size. Materials must be able to pour through a 6.0 to 8.0-mm [¹/₄ to ⁵/₁₆ in.] diameter funnel outlet when in an aerated state. 1.3 This method consists of eight measurements and two calculations for Carr Indices as follows. Each measurement, or calculation, or combination of them, can be used to characterize the properties of bulk solids. 1.3.1 Measurement of Carr Angle of Repose 1.3.2 Measurement of Carr Angle of Fall 1.3.3 Calculation of Carr Angle of Difference 1.3.4 Measurement of Carr Loose Bulk Density 1.3.5 Measurement of Carr Packed Bulk Density 1.3.6 Calculation of Carr Compressibility 1.3.7 Measurement of Carr Cohesion 1.3.8 Measurement of Carr Uniformity 1.3.9 Measurement of Carr Angle of Spatula 1.3.10 Measurement of Carr Dispersibility 1.4 All observed and calculated values shall conform to the guidelines for significant digits and rounding established in Practice D6026 . 1.4.1 The procedures used to specify how data are collected/recorded or calculated in this standard are regarded as the industry standard. In addition, they are representative of the significant digits that generally should be retained. The procedures used do not consider material variation, purpose for obtaining the data, special purpose studies, or any considerations for the user's objectives: and it is common practice to increase or reduce significant digits of reported data to be commensurate with these considerations. It is beyond the scope of this standard to consider significant digits used in analysis methods for engineering design. 1.5 Units- The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other, and values from the two systems shall not be combined. Combining values from the two systems may result in nonconformance with the standard. 1.6 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use. 1.7 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

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