Metrology standardization

The National Institute of Metrology, Standardization and Industrial Quality (InMetro)... 

Pollution also affects the manufacture of certain materials and products. This is evidenced by the need for clean rooms in metrology standards laboratories and in the production of certain electronics materials and of component assembly operations, In addition to elaborate filtering systems, such rooms are held at a slightly positive pressure (above outside atmospheric pressure) to prevent the entry of raw air from the outside. 

Consider what the consequences of setting the probability level for acceptance of H0 at 90, 95, and 99% might be. As an example suppose an analytical method has been used to analyze a certified reference material for the element zinc, that is, a material whose amount of substance of zinc has been established to a high metrological standard with low measurement uncertainty, with a view to deciding if there is any significant systematic error in the method. The mean of n measurement results has been determined and suppose that the population standard deviation (a), and therefore the standard deviation of the... 

In doing this the problems may arise if one person alone manages several processes, i.e. if his activity embraces a number of functions (as may be especially typical for NDT). It is better if each process is assigned to a specialist responsible for it. For example, persons responsible for the technical state of NDT equipment, for metrological confirmation of NDT facilities, for standards on testing, for NDT results registration, etc. 

The main tasks of metrological maintenance of NDT equipment and standard blocks on compliance with standard of Belarus CTB 8004-93 are ... 

The work on standardisation in Ukraine is led by the State Committee of Ukraine on Standardisation, Metrology and Certification (Gosstandardt), All the USSR standards (GOSTs) are valid in Ukraine, and several dozens of them were elaborated in the NDT field. 

Metrologia International Committee of Weights and Measures (CIPM) Pavilion de Breteuil Parc de St. Cloud, Prance Includes articles on scientific metrology worldwide, improvements in measuring techniques and standards, definitions of units, and the activities of various bodies created by the International Metric Convention. 

The complex of the following destmctive and nondestmctive analytical methods was used for studying the composition of sponges inductively coupled plasma mass-spectrometry (ICP-MS), X-ray fluorescence (XRF), electron probe microanalysis (EPMA), and atomic absorption spectrometry (AAS). Techniques of sample preparation were developed for each method and their metrological characteristics were defined. Relative standard deviations for all the elements did not exceed 0.25 within detection limit. The accuracy of techniques elaborated was checked with the method of additions and control methods of analysis. 

Application of IP and NCS in conjunction with specification tolerance limits enables to substantiate acceptance criteria for linear regression metrological characteristics (residual standard deviation, correlation coefficient, y-intercept), accuracy and repeatability. Acceptance criteria for impurity influence (in spectrophotometric assay), solution stability and intermediate precision are substantiated as well. 

The measurement range of a thermistor is dependent on the probe type, typically -100 to +300 °C. The stability is not as good as that of metallic resistances. Thermistors are not standardized like some of the metallic probes. The thermistor has the advantage of a high change of the resistance with temperature. A very wide variety of sizes and shapes and a low price makes them attractive in relation to the metrological performance. 

The so-called standard instrument is used for interpolation between the fixed points and for the calibration of other thermometers lower in the metrological hierarchy. The standard instrument in the moderate temperature range is a special platinum resistance probe, as it has to fulfill set requirements. It is important in all calibration that traceability to a primary normal, here the fixed-point ITS-90 scale, exists. 

The key difference between a CRM and an RM is the traceability. In order to play any role at aU in metrology, traceability is a key property. Traceability refers to a property value of the CRM, and thus to the underlying measurements. Insufficient traceability of these measurement results will eventually lead to a RM that cannot be certified, as the property value cannot be related to other standards. In the ideal case, traceability is realized up to the International System of Units, SI, but this is only feasible for a very small number of CRMs. 

The BERM symposia have served further to clarify understanding of the basic attributes of a good reference standard that is indispensable for establishing new frontiers in the science of measurements, and to highlight the invaluable infrastructure and proven record of metrological excellence available at the National Measurement Institutes to accomplish such tasks. 

These symposia, in bringing together experts from international metrology arid standards institutions, managers from governmental regulatory agencies, and the private producers and users of RMs, have documented an impressive list of accomplishments. 

What if instruments could be designed which were remoteiy self-calibrating with respect to calibration services of a National Metrology Institute (NMI) While this may sound very far-fetched , it is not difficult to speculate that future application of telemetry, transducers, intrinsic standards, detectors and computers will link some instruments directly to a NMI to obviate their need for RMs (Rasberry 1998). 

Installation qualification (IQ). IQ demonstrates that the equipment/system has been installed correctly at the user site according to vendor standards. The vendor should install the equipment to demonstrate to the buyer that all the components are operating properly. The qualification process includes appropriate documentation of the system components, physical installation and hook-up, and a performance check to verify that the individual components operate and can communicate with each other. System component information, such as serial numbers, type of use, and user performance requirements, should be included in the metrology database for easy tracking and scheduling of maintenance and/or calibration. 

ISO 3534-1 (1993), International Organization for Standardization (BIPM, IEC, IFCC, ISO, IUPAC, IUPAP, OIML), International vocabulary of basic and general terms in metrology. Geneva... 

International Vocabulary of Basic and General Terms in Metrology , 2nd Edition, ISBN 92-67-10175-1, International Organization for Standardization (ISO), Geneva, Switzerland, 1993. 

Section 5.2 introduced the subject of metrological traceability and calibration and the use of pure chemical substances and reference materials in achieving trace-ability. Reference materials are used as transfer standards. Transfer standards are used when it is not possible to have access to national or international standards or primary methods. Transfer standards carry measurement values and can be... 

Traceable equipment, e.g. balances, thermometers, glassware, timepieces, pipettes, etc. are appropriately calibrated, and the corresponding certificates or other records demonstrating metrological traceability to National Standards are available. 

A G. Khandryga (Manager, Industrial Product Certification Dept., Dnepropetrovsk Center for Standardization and Metrology). We do certify... 

In conclusion, one must insist on the importance of the main metrological characteristic, the traceabilility (generally of a result), ensuring a clear (unbroken) relationship between the final result and the complete measurement scheme by using appropriate procedures, standards and calibrated equipment. However, for chemical metrology and particularly for on-site measurement, some adaptations are needed for a wider meaning of traceability [66]. 

Snow, especially its water-soluble fraction, is one of the most sensitive and informative indicators of mass-transfer in the chain air - soil - drinking water. Therefore analytical data on snow-melt samples were selected for inter-laboratory quality control. Inter-laboratory verification of analytical results estimated in all the groups have shown that relative standard errors for the concentrations of all the determined elements do not exceed (5-15)% in the concentration range 0.01 - 10000 microg/1, which is consistent with the metrological characteristics of the methods employed. All analytical data collected by different groups of analysts were tested for reliability and... 

Primary Standard Standard that is designated or widely acknowledged as having the highest metrological qualities and whose value is accepted without reference to other standards of the same quality. 

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