ASTM D4356-84(1996)

1.1 This practice should be used in the development of any test method in which the determination value is calculated from measurement values by means of an equation. The practice is not applicable to such determination values as those calculated from counts of nonconformities, ratios of successes to failures, gradings, or ratings.

1.2 The purpose of this practice is to provide guidance in the specifying of realistic and consistent tolerances for making measurements and for reporting the results of testing.

1.3 This practice can be used as a guide for obtaining the minimum test result tolerance that should be specified with a particular set of specified measurement tolerances, the maximum permissible measurement tolerances which should be specified to achieve a specified test result tolerance, and more consistent specified measurement tolerances.

1.4 These measurement and test result tolerances are not statistically determined tolerances that are obtained by using the test method but are the tolerances specified in the test method.

1.5 In the process of selecting test method tolerances, the task group developing or revising a test method must evaluate not only the consistency of the selected tolerances but also the technical and economical feasibility of the measurement tolerances and the suitability of the test result tolerance for the purposes for which the test method will be used. This practice provides guidance only for establishing the consistency of the test method tolerances.

1.6 This practice is presented in the following sections:

Number Scope 1 Referenced Documents 2 TERMINOLOGY Definitions 3 Discussion of Terms 4 Expressing Test Method Tolerances 5 Tolerance Symbols 6 SUMMARY AND USES Summary of Practice 7 Uses and Significance 8 MATHEMATICAL RELATIONSHIPS Propagation Equations 9 Tolerance Terms 10 Determination Tolerances 11 Consistency Criteria 12 APPLICATION OF PRINCIPLES Procedure 13 Mass per Unit Area Example 14 ANNEXES General Propagation Equation A1 Specific Propagation Equations A2

1.7 This standard may involve hazardous materials, operations, and equipment. This standard does not purport to address all of the safety problems 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.