ASME B89.7.3.1:2001 pdf download

ASME B89.7.3.1:2001 pdf download.CUIDELINES FOR DECISION RULES: CONSIDERING MEASUREMENT UNCERTAINTY IN DETERMINING CONFORRIIANtE TO SPECIFICATIONS
1 SCOPE
These guidelines provide terminology and specify the content that must be addressed when stating a decision rule used for deciding the acceptance or rejec- tion of a product according to specification.
2 DEFINITIONS
decision rule: a documented rule, meeting the require- ments of section 3 of these guidelines, that describes how measurement uncertainty will be allocated with regard to accepting or rejecting a product according to its specification and the result of a measurement. binary decision rule: possible outcomes, either acceptance or rejection.’ specification zone (of an instrument or workpiece): the set of values of a characteristic between, and including, the specification limits.2* 39 a decision rule with only two measurand: particular quantity subject to measure- ment. See VIM. 2.6.’ expanded uncertainiy: quantity defining an interval about the result of a measurement that may be expected to encompass a large fraction of the distribution of values that could reasonably be attributed to the measur- and. See GUM, 2.3.5.uncertainty interval (of a measurement): the set of values of a characteristic about the result of a measure- ment that may be expected to encompass a large fraction of the distribution of values that could reasonably be attributed to the measurand.69 ’ N:l decision rule: a situation where the width of the specification zone is at least N times larger than the uncertainty interval for the measurement result.’ acceptance zone: the set of values of a characteristic, for a specified measurement process and decision rule, that results in product acceptance when a measurement result is within this zone.’ rejection zone: the set of values of a characteristic, for a specified measurement process and decision rule, that results in product rejection when a measurement result is within this zone.” transition zone: the set of values of a characteristic, for a specified measurement process and decision rule, that is neither in the acceptance zone nor rejection zone.
guard band: the magnitude of the offset from the specification limit to the acceptance or rejection zone boundary.12, 13, 14, 15. 16, 17 simple acceptance: the situation when the acceptance zone equals and is identical to the specification zone. simple rejection: the situation when the rejection zone consists of all values of the characteristic outside the specification zone. stringent acceptance: the situation when the accept- ance zone is reduced from the specification zone by a guard band(s). See Fig. 1. ’*, I9 relaxed rejection: the situation when the rejection zone is partially inside the specification zone by the amount of a guard band. See Fig. 1.’* relaxed acceptance: the situation when the acceptance zone is increased beyond the specification zone by a guard band.
3 REQUIREMENTS FOR DECISION RULES
3.1 Zone Identification A decision rule must have a well-documented method of determining the location of the acceptance, rejection, and any transition zones. 3.2 Decision Outcome Each zone of a decision rule must correspond to a documented decision that will be implemented should the result of measurement lie in that zone. While this is automatic for the acceptance and rejection zones by definition, any transition zones must have their corresponding decision outcome documented. 3.3 Repeated Measurements A decision rule must state the procedure for ad- dressing repeated measurements of the same characteris- tic on the same workpiece or instrument. See Appendix B for further discussion of this issue. 3.4 Data Rejection A decision rule must state the procedure for allowing data rejection with cause, that is, rejection of “outliers.” See Appendix C for further discussion of outliers.