1.1本规程旨在协助各技术委员会使用统一方法来指示在规范限制中被视为重要的位数，例如规定的最大值和规定的最小值。其目的是概述有助于澄清规范限值预期含义的方法，在确定与规范的符合性时，将观察值或计算的测试结果与之进行比较。 1.2当适用的ASTM规范或标准直接参考本规程时，本规程旨在用于确定是否符合规范。 1.3只有在指明了方法的选择时，参考本惯例才有效，即: 绝对法或舍入法 .

1.1 This practice is intended to assist the various technical committees in the use of uniform methods of indicating the number of digits which are to be considered significant in specification limits, for example, specified maximum values and specified minimum values. Its aim is to outline methods which should aid in clarifying the intended meaning of specification limits with which observed values or calculated test results are compared in determining conformance with specifications. 1.2 This practice is intended to be used in determining conformance with specifications when the applicable ASTM specifications or standards make direct reference to this practice. 1.3 Reference to this practice is valid only when a choice of method has been indicated, that is, either absolute method or rounding method .