Important Broad-Based Metrology Concepts in the Revised U.S. Micrometer Standard

A revision to the U.S. standard on micrometers, ASME B89.1.13, was approved by the ASME B89 dimensional metrology standards committee in 2012, and final publication of the standard is expected in 2013. This standard includes many modern and novel calibration concepts that apply beyond the dimensional field, and the purpose of this paper is to communicate some of the highlights of this new standard to the larger metrology community. Some of the key issues include defining the measurand, traceability requirements, conformance decision rules, calibration versus verification, and measurement uncertainty. It is expected that some of the concepts in the revised ASME B89.1.13 will be controversial, for example the intentional lack of inclusion of the resolution of the unit under test in the estimation of measurement uncertainty. By presenting this new standard in completion, it is hoped that others will understand and appreciate the reasoning behind some of the novel and controversial concepts in this standard and therefore be able to apply some of the ideas not just to micrometers but to other fields of metrology as well.