Measurement Equipment

Posgay, G. and Imre, L. Detection of Stresses Using Multiplex Barkhausen Noise Measuring Equipment Proc. 8 th DAS on Experimental Methods in Solid Mechanics, Godollo, 1991, Edited 1.. Huszdr, pp. 19-19/2... 

A first comprehensive round robin test described in 4.1 which is open to all interested parties will be followed periodically by round robin tests in a reduced extent to ensure the further harmonisation of measurement procedures. The check of measurering equipments and procedures is an inalienable requirement for the further steps for providing the users with constant film quality. Together with sample tests performed by BAM as indicated in section 4.2 and and the production control by the manufacturer it will be possible to survey the film systems whether they meet the requirements of one of the film classes of EN 584-1. 

The verifications can be performed by the user himself, with electronic measurement equipment described in this project. The consequences of the application of future European standard are very important since is established a mandatory verification of each particular flaw detector, at least once a year. Their verification is to be performed according to a well defined procedure of measurement, including acceptance criteria for each parameter. 

It may be realised by means of definite complex of intereonneeted and interrelated common rules and norms direeted to the assurance of traceability and uniformity of measuring equipment, NDT equipment including. In another words NDT equipment must be metrologically supported. 

Flow measuring equipment must generally be wet caHbrated to attain maximum accuracy, and principal flow meter manufacturers maintain extensive facihties for this purpose. In addition, a number of governments, universities, and large flow meter users maintain flow laboratories. 

Both ultrasonic and radiographic techniques have shown appHcations which ate useful in determining residual stresses (27,28,33,34). Ultrasonic techniques use the acoustoelastic effect where the ultrasonic wave velocity changes with stress. The x-ray diffraction (xrd) method uses Bragg s law of diffraction of crystallographic planes to experimentally determine the strain in a material. The result is used to calculate the stress. As of this writing, whereas xrd equipment has been developed to where the technique may be conveniently appHed in the field, convenient ultrasonic stress measurement equipment has not. This latter technique has shown an abiHty to differentiate between stress reHeved and nonstress reHeved welds in laboratory experiments. 

Methods used for the tensile testing of single fibers and fibers taken from yams and tows are discussed in ASTM D3822 and D2101. Measurement equipment used in fiber tensile testing is described in ASTM D76. An overview of test procedures and their significance is also available (3,10). 

Techniques for efficiently and economically measuring the other important characteristics, ie, length, strength, and position of weakness in the fiber, are now in commercial use. Existing color-measuring equipment can be used to measure the color (whiteness or yellowness) of washed wool, but accurate measuring of colored-fiber content remains a problem (5,8). 

The assessor should also find out whether an effective testing program is in place to help ensure the serviceability of process measurement equipment. The successful toller should have an established calibration program to address the accuracy of critical measurement equipment. Safety critical process parameters should be monitored and critical process equipment should automatically interlock when monitoring instrumentation detects safety critical deviations. Interlocks should either facilitate a remedy to the critical deviation or bring the process to the zero energy state. These instruments and interlocking devices should be routinely tested to ensure operational reliability. 

Is precision of production measuring equipment routinely monitored (via control charts or other similar techniques) ... 

Is all measuring equipment used, tested and calibrated for accuracy at regular intervals ... 

The assessor should find out that a testing program is in place, which ensures the serviceability of the existing measurement equipment. They should have an established calibration program, which addresses the accuracy of all measurement equipment. 

Fig. 4.46. Schematic diagram of IBSCA measurement equipment this usually combined with a mass spectrometer (SIMS or SNMS).

The measurement range for platinum is -200 to +800 °C, for nickel -50 to +250 °C, and for copper -50 to +200 °C. The advantages are good accuracy, almost linear characteristics, and stability. A disadvantage is the small change of resistance with temperature, which requires a high sensitivity from the rest of the measurement equipment. 

The measured pressure differences in ventilation applications are low or very low. The measurement range varies from a few pascals to several thousand pascals. At the lower end are typically building leakage and air movement-related measurements, where only a few pascals can cause a remarkably large air-tlow. The largest pressure differences probably occur in fan performance determination and similar applications. This wide range requires special demands on the measuring equipment and selection of the correct instrument for each application (Fig. 12.15). 

Is measuring equipment selected on the basis of the accuracy and precision required and do all measurements have a known relationship to National Standards ... 

You will need to review the requirements and the resultant design to identify any special equipment, tools, test software, and test or measuring equipment required. Once identified, plan for its design, manufacture, procurement, verification, and certification. One way of doing this is to produce a list that contains the following details ... 

All measuring equipment to be within calibration during the tests... 

Traceability is also important to control processes. You may need to know which products have been through which processes and on what date, if a problem is found some time later. The same is true of test and measuring equipment. If on being calibrated a... 

Make provision in inspection and test records to capture details of inspection, test, and measuring equipment used. 

Define the inspection aids and test equipment to be used. There may be jigs, fixtures, gages, and other aids needed for inspection. Standard measuring equipment would not need to be specified as your inspectors and testers should be trained to select the right tools for the job. Any special test equipment should be identified. 

Provide inspection aids, tools, and measuring equipment appropriate for the task. 

It is not necessary to calibrate all test and measuring equipment. Some equipment may be used solely as an indicator, such as a thermometer, a clock, or a tachometer other equipment may be used for diagnostic purposes, to indicate if a fault exists. If such devices are not used for determining the acceptability of products and services or process parameters, their calibration is not essential. However, you should identify such devices as for Indication Purposes Only if their use for measurement is possible. You don t need to identify all clocks and thermometers fixed to walls unless they are used for measurement. Having observed that you record the time when observations were made, a zealous assessor may suggest that the clock be calibrated. If the time is not critical to product or process acceptability, calibration is unnecessary. 

ISO 10012 requires that the integrity of measuring equipment be confirmed at appropriate intervals established on the basis of stability, purpose, and usage. With new equipment it is customary to set the frequency at 12-month intervals unless recommended otherwise by the manufacturer. Often this frequency remains despite evidence during calibration that accuracy and precision is no longer stable. Such action indicates that the calibration staff have not been properly trained or that cost rather than quality... 

The purpose of this requirement is to ensure that the integrity of the measurements is maintained by precluding errors that can occur if measuring equipment is tampered with. 

Unlike the other requirements, which only referred to inspection, test, and measuring equipment, this clause adds test facilities. Facilities include the equipment and the area or room in which it is kept or used. Test facilities are any room, area, or complex in which tests are carried out. Inspection, measuring, and test facilities include functional and environmental test laboratories, test and inspection chambers, calibration rooms. 

Validate software used for measurement purposes or for driving measuring equipment. 

Don t continue using measuring equipment that has sustained damage even if it appears to have had no effect. 

Don t purchase any second-hand measuring equipment without the original manual. 

Don t permit measuring equipment to collect on the floor while waiting calibration. 

ISO 9001 covers the design, purchasing, handling, and measuring equipment activities in the appropriate clauses. The maintenance addressed in clause 4.9 relates only to processing equipment and not to the product that is an output of the process. To provide adequate procedures for product maintenance you will need to ... 

The only statistical techniques which need control are those used to determine the acceptability of a product or service or the capability of a process that produces the product or service. Any activity where you rely on statistical evidence rather than physical measurement is an activity which should be governed by these requirements. The use of recognized techniques is important to the confidence one has in the result. It is similar to the use of measuring equipment that has been calibrated against known standards of accuracy. Unless you actually check every product, measure every attribute or variable you cannot be 100% certain. But that is costly and you can be 99.99% certain by using statistical techniques 99.99% may be sufficiently accurate for your needs. 

Perform studies to show that the combination of measurement equipment tolerances or variations in the design tolerances cannot result in nonconforming product. 

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