ASTM D 5220/D 5220M:2026

1.1 This test method covers the measurement of the water mass per unit volume of soil and rock by thermalization or slowing of fast neutrons, where the neutron source and the thermal neutron detector are placed at the desired depth in the bored hole lined by an access tube. 1.1.1 For limitations see Section 6 on Interferences. 1.2 The water mass per unit volume, expressed as mass per unit volume of the material under test, is determined by comparing the thermal neutron count rate with previously established calibration data (see Annex A1 ). 1.3 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. 1.3.1 Reporting of test results in units other than SI shall not be regarded as nonconformance with this standard. 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 should generally 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 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. Specific hazards are given in Section 8 . 1.6 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.

13.080.40