Determine oxidation stability of steam turbine oils by rotating pressure vessel
20. Precision and Bias
20.1 The precision and bias statement is generated from the research report (95 % confidence). The data range of results in the research report is from 100 to over 3000 min.
20.1.1 Repeatability - The difference between successive test results obtained by the same operator with the same apparatus under constant operating conditions on identical test material, would in the long run, in the normal and correct operation of the test method, exceed the following values only in one case in twenty:
Repeatability = 0.24 (X + 103)
where:
X = denotes mean value.
20.1.2 Reproducibility - The difference between two single and independent results obtained by different operators working in different laboratories on identical test material, would in the long run, in the normal and correct operation of the test method, exceed the following values only in one case in twenty:
Reproducibility = 0.43 (X + 103)
where:
X = denotes mean value.
NOTE 18 - This precision statement was prepared with data on eight oils (Group I-IV base stocks) tested by eight cooperators. The oils covered values in the ranges from 100 to over 3000 min.
20.2 Bias - There being no criteria for measuring bias in these test-product combinations, no statement of bias can be made.
21. Keywords
21.1 dry block bath; induction period; liquid bath; oxidation stability; rotating pressure vessel; steam turbine oils
