The data from this test can be used to estimate the bulk density of materials in bins and hoppers and for material handling applications such as feeders.

The test results can be greatly affected by the sample selected for testing. For meaningful results it is necessary to select a representative sample of the particulate solid with respect to moisture (water) content, particle-size distribution and temperature. For the tests an appropriate size sample should be available, and fresh material should be used for each individual test specimen.

Initial bulk density, (ρ_b)_initial, may or may not be used as the minimum bulk density. This will depend on the material being tested. For example, the two are often close to the same for coarse (most particles larger than about 6 mm), free-flowing bulk solids, but not for fine, aeratable powders.

Bulk density values may be dependent upon the magnitude of the applied mass increments. Traditionally, the applied mass is doubled for each increment resulting in an applied mass increment ratio of 1. Smaller than standard increment ratios may be desirable for materials that are highly sensitive to the applied mass increment ratio. An example of the latter is a material whose bulk density increases 10% or more with each increase in applied mass.

Bulk density values may be dependent upon the duration of each applied mass. Traditionally, the duration is the same for each increment and equal to 15 s. For some materials, the rate of compression is such that complete compression (no change in volume with time at a given applied compressive stress) will require significantly more than 15 s.

Note 1—The quality of the result produced by this standard is dependent on the competence of personnel performing it, and the suitability of the equipment and facilities used. Agencies that meet the criteria of Practice D 3740 are generally considered capable of competent and objective testing/sampling/inspection/etc. Users of this standard are cautioned that compliance with Practice D 3740 does not in itself assure reliable results. Reliable results depend on many factors; Practice D 3740 provides a means of evaluating some of those factors. Practice D 3740 was developed for agencies engaged in the testing or inspection (or both) of soil and rock. As such it is not totally applicable to agencies performing this standard. However, users of this standard should recognize that the framework of Practice D 3740 is appropriate for evaluating the quality of an agency performing this standard. Currently there is no known qualifying national authority that inspects agencies that perform this standard.

1.1 This test method covers an apparatus and procedure for determining a range of bulk densities of powders and other bulk solids as a function of compressive stress.

1.2 This test method should be performed in the laboratory under controlled conditions of temperature and humidity.

1.3 All observed and calculated values shall conform to the guidelines for significant digits and rounding established in Practice D 6026.

1.3.1 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.

1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.

1.5 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.