PTC XX. TEST UNCERTAINTY. Proposed Revision of PTC “ Test Uncertainty”. Par Adjustment in response to comment. TENTATIVE. The edition of ASME PTC will be revised when the Society .. All Performance Test Codes must adhere to the requirements of ASME PTC 1, General. Most Sections in this revision of ASME PTC [1] are rewritten to both add to the available technology for uncertainty analysis and to make it easier for.

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This case is called a single otc result. The facility simulates altitude by lowering system uncertainty can be obtained. Figliola, Clemson University H. A t value of 1. If a sensitivity coefficient depends on the values of any averages, i.

ASME PTC 试验不确定度 Test -电源技术相关资料下载-EEWORLD下载中心

For the purposes of this example, a summary w of this evaluation is presented in Table A problem clearly exists when there pttc z no overlap between uncertainty intervals.

A forward differencing scheme wsme used with a value of Qx equal w to 0. It may xsme be used to compare alternative instrumentation systems and test designs and to determine corrective action if the predicted uncertainty w is unacceptably large. In successive measurements of the parameter, the values of these elemental random error sources change resulting in the random scatter evident in the successive measurements.

If flowmeters 1, 2, and 3 are calibrated against the same standard, and flowmeter 4 is calibrated against a different standard, the systematic standard uncertainty for z is larger than if all the meters had been calibrated against different standards Case 1.


The latter describes the limits to which a systematic error may be expected to go with some confidence. Friedman, Vice Chair S.

A pretest uncertainty analysis is based on data and information that exist before the test, such as calibration histories, previous tests with similar instrumentation, prior w measurement uncertainty analyses, expert opinions, and, if necessary, special tests.

The cator elemental systematic standard uncertainties associ- 6 systematic error resulting from imperfect ated ptv the error sources identified in para. Even though the pressure transducer in Program 2 had a systematic standard uncertainty of more than twice those of the transducers in Program 1, the systematic standard uncertainty of the result for Program 2 was less than half of that for Program 1.

ASME PTC 19.1-2005 试验不确定度 Test Uncertainty.pdf

The same is true for the Xj z data points. Knowledge of the frequency distribution and standard deviation of this population permits de- When tests are duplicated under similar but somehow changed operating conditions, these generate multiple data sets for the measured parameters. The large sample uncertainty expression given in eq. The partial correlation for the pressure measurement must be derived from the elemental uncertainties.

It will vary as a function of sample size. Depending on the application, vari- w ous confidence levels may be appropriate. This example is nearly identical to that presented H2O.

Now suppose an experimental result, r, is wdefined as a function of certain measured variables, C The difference between the results of these tests is an indication of the effect of the design change. Calibrations are also used to provide traceability to known reference standards or physical constants, or both. The total uncertainty in a measurement is the combination of uncertainty due to random error and uncertainty due to systematic error. In this section, only a special case is considered for the systematic standard uncertainty.


Spatial variation effects are considered errors of method see para. The first test is run with the standard or baseline configuration. Thus, it often is necessary to install several measurement sensors at different spatial locations to account for spatial variations of the parameter being measured. Measurements at each traverse point can be used to determine local fluid velocity.

The uncertainty estimate for discharge coefficient comes from calibration data, which has been fossilized, and is listed as a systematic uncertainty in Table The specific value of this statistic must be selected on the basis of the defined confidence level and degrees of freedom associated with the confidence interval. The results are plotted in Fig. Additionally, a pretest uncertainty analysis facilitates communication between all parties to the test about the expected quality of the test. The proposed code or standard was made available for public review and comment that provides an opportunity for additional public input from industry, academia, z regulatory agencies, and the public-at-large.

Specifically, a tolerance interval is applicable if o limits are needed that contain most of the sampled population, while a prediction interval would be used to obtain limits to contain all of a small.

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