Quality Control and Traceability of Pressure Measurement

摘要

There have been increasing demands for accurate measuring instruments with certain expression concerning it's confidence that should be recognized beyond borders and based on internationally acceptable standards. This strong trend has caused by many efforts of each economy to enter into the framework of the World Trade Organization (WTO). There is an article in ISO-9000s as quality management requirements, all the measurement results should have reasonable Traceability to keep their confidence. And also there is an definition for Traceability such as ' property of the result of a measurement or the value of a standard whereby it can be related to stated references, usually national or international standards, through an unbroken chain of comparisons all having stated uncertainties.' It is possible to imagine an idealistic situation of fully traceable measurements, but difficult to realize an actual acceptable methodology that achieves rational Traceability with reasonable cost. One of major difficulties to achieve Traceability is a lack of technical experience to use uncertainty for quality control and evaluation. In this paper, a case of pressure measuring instruments is examined as a typical example of actual industrial application, and a methodology is proposed to introduce uncertainty into quality control of pressure measurement in conjunction with already existing engineering techniques such as maximum permissible error (MPE) or tolerance, accuracy class of instruments, and regulation of instruments, etc.