Role of measurement uncertainty in conformity assessment in legal metrology and trade

Conformity assessment, focused on risks quantification, evolved from being binary to being probabilistic. In fact, new methods described by the standard ISO CEI guide 98-4 [1] and FD X 07-039 [2] show how measurement uncertainty is integrated in the conformity assessment (FD X 07-039 : “Role of measurement uncertainty in conformity assessment – implementation of NF ISO/IEC Guide 98-4 – illustration through industrial case studies”). In such a probabilistic framework, the conformity assessment relies on two quantities: the measurement with its related uncertainty and the measurand prior knowledge. Both quantities are combined statistically to determine measurand posterior knowledge, and to quantify a global or specific risks either for the producer or the consumer. The standard also defines how integrating those two quantities improves the reliability of decisions based on measurements. This work will first present a clarification of the probabilistic approach described by the FD X07-039. Then, the measurand prior knowledge use will be explained. Finally, future metrology applications caused by such an approach will be listed.

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Forensic Investigation of Four Monitored Green Infrastructure Inlets

Water ◽

10.3390/w13131787 ◽

2021 ◽

Vol 13 (13) ◽

pp. 1787

Author(s):

Leena J. Shevade ◽

Franco A. Montalto

Keyword(s):

Measurement Uncertainty ◽

Green Infrastructure ◽

Stormwater Management ◽

Catchment Area ◽

Low Flow ◽

Inflow Rate ◽

Forensic Investigation ◽

Flow Conditions ◽

The Mean

Green infrastructure (GI) is viewed as a sustainable approach to stormwater management that is being rapidly implemented, outpacing the ability of researchers to compare the effectiveness of alternate design configurations. This paper investigated inflow data collected at four GI inlets. The performance of these four GI inlets, all of which were engineered with the same inlet lengths and shapes, was evaluated through field monitoring. A forensic interpretation of the observed inlet performance was conducted using conclusions regarding the role of inlet clogging and inflow rate as described in the previously published work. The mean inlet efficiency (meanPE), which represents the percentage of tributary area runoff that enters the inlet was 65% for the Nashville inlet, while at Happyland the NW inlet averaged 30%, the SW inlet 25%, and the SE inlet 10%, considering all recorded events during the monitoring periods. The analysis suggests that inlet clogging was the main reason for lower inlet efficiency at the SW and NW inlets, while for the SE inlet, performance was compromised by a reverse cross slope of the street. Spatial variability of rainfall, measurement uncertainty, uncertain tributary catchment area, and inlet depression characteristics are also correlated with inlet PE. The research suggests that placement of monitoring sensors should consider low flow conditions and a strategy to measure them. Additional research on the role of various maintenance protocols in inlet hydraulics is recommended.

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