5.1 The guidelines presented in this practice for retaining significant digits and rounding numbers may be adopted by the using agency or user. Their adoption should generally be used to calculate and record data when specified requirements are not included in a standard.

5.2 While this practice originated when most geotechnical data were manually collected and recorded on data forms, tables, or into computers, the use of digital acquisition, calculations, and reporting of data has become more common. When calculators and computers are used for data collection, the significant digits may not meet the requirements specified in this standard. Nevertheless, their use shall not be regarded as nonconforming with this practice.

5.3 The guidelines presented herein should not be interpreted as absolute rules but as guides to calculate and report observed or test data without exaggerating or degrading the precision of the values.

5.3.1 The guidelines presented emphasize recording data to enough significant digits or the number of decimal places to allow sensitivity and variability analyses to be performed.

1.1 Using significant digits in geotechnical data involves the processes of collecting, calculating, and recording either measured values or calculated values (results) or both. This practice is intended to promote uniformity in recording significant digits for measured and calculated values involving geotechnical data.

1.2 The guidelines presented are industry standard and are representative of the significant digits that should be retained in general. The guidelines do not consider material variation, the 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.

1.3 It is beyond the scope of this practice to consider significant digits used in analysis methods for engineering design.

1.4 This practice accepts a variation of the traditional rounding method that recognizes the algorithm common to most hand-held calculators and computers, see 6.2.3. The traditional rounding method (see 6.2) is in accordance with Practice E29, ASTM Manual 7, or IEEE/ASTM SI 10.

Note 1: Calculators and computers often present and use many digits in their output and calculations, which may not all be significant. It is the responsibility of the programmer and user to make sure that the measured and calculated values are handled, interpreted and reported properly using these guidelines.

1.5 This practice offers a set of instructions for performing one or more specific operations. This document cannot replace education or experience and should be used in conjunction with professional judgment. Not all aspects of this practice may be applicable in all circumstances. This ASTM standard is not intended to represent or replace the standard of care by which the adequacy of a given professional service must be judged, nor should this document be applied without consideration of a project’s many unique aspects. The word “Standard” in the title means only that the document has been approved through the ASTM consensus process.

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.