The absolute random standard uncertainty for the test result is [see eq. Otherwise, these elemental systematic standard uncertainties are combined per subsection It is assumed that these estimates are based on. The values for h1 and h2 are evaluated at the measured inlet and exit conditions. In some countries, a national standards laboratory is at the apex of these hierarchies, providing the ultimate reference for every standards laboratory.

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For example, taking multiple measurements as a function of time while holding all other conditions constant would identify the random asme ptc 19.1 associated with the measurement system and the unsteadiness of the test condition. Depending on the application, uncertainty sources may be classified either by the asme ptc 19.1 effect systematic or random on the measurement or test result, or by the process in which they may be quantified Type A or Type B. This ptd accomplished by adding an addi- tional random term.

This probability is known as the associated confidence level. The engineer must decide upon the relevant questions. Theory and Design for Mechanical Measurements. The estimates of the elemental errors fall into two w categories: By looking at the numbers in the last two columns of Table The value for h2s, however, must be evaluated at a w state corresponding to the measured exit pressure but assuming isentropic compression has occurred. More precisely, over a large number of samples, the interval calculated in this manner will contain the unknown mean 95 percent of the time.

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The absolute systematic standard uncertainty for w the test result is [see eq. This uncertainty of method is sometimes 91.1 to as uncertainty sV 1 0. The expanded uncertainty of the average circulating water bath temperature measurement is evaluated using eqs.

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

The results of this analysis are summarized in Table Thus, it often is necessary to install several measurement sensors at different spatial locations to account for spatial variations of the parameter being measured. A t value of 1. Some are also aware of tolerance intervals, but most nonstatisticians know very little about asme ptc 19.1 intervals despite their practical importance. Once the pct to be answered have been clearly stated, it should be easy to decide upon the correct intervals.

Uncertainty Analysis for Dummies – Discussion Forums – National Instruments

An eloquent treatment of these terms is given by Gerald Hahn [24] in his paper, which is. Thus, one may be 95 percent confident that the preceding interval contains at least 90 percent of the sampled five columns of Table A The systematic values were evaluated and are listed in Table 2. The significance of this is discussed in para.

This section provides an asme ptc 19.1 of how the measurement process should be defined. asje


This paragraph presents a method for determining nonsymmetric uncertainty intervals in these cases [11]. There usually will be some elemental systematic standard uncertainties that will be dom- z inant.

A quick and easy way to asme ptc 19.1 calculate the sensitivity coefficients of the independent m parameters is to develop a table using a spread- sheet program on the personal computer. In this paragraph we will relate these two sources of variance in the measured variables, Xj, to the variance in an asme ptc 19.1 result r X1, X2.


An automotive test facility may only be able to test at specified altitudes and speeds, pc the effects at other altitude conditions may need to be extrapolated.

ASME PTC – Test Uncertainty

Accurate measurement requires w minimizing both random and systematic errors asme ptc 19.1 Fig. For this particular example, the assumptions of the analysis method used to compute the adiabatic efficiency of the compressor were not identified as sources of error. The probability of not rejecting a bad data point is not fixed. Uncertainties in Absolute Terms. The guarded hot plate is used because it is relatively inexpensive and effective in providing the boundary conditions necessary to ptd one dimensional heat flow through the material.

In computing the preceeding sensitivity coefficients, it was assumed that the specific heat ratio is independent of air temperature. This asme ptc 19.1 the need to develop weighting factors fx for each sample area. In addition, it is applicable for all known measurement and test uncertainty analyses.