ASTM D943 method for oxidation characteristics of inhibited mineral oils
11. Report
11.1 Report the calculated hours to 2.0 mg KOH/g acid number (oxidation lifetime).
12. Precision
12.1 The following criteria should be used for judging the acceptability of results (95 % confidence) in the data range from 700 to 3900 h:
12.1.1 Repeatability - The difference between concurrent test results obtained by the same operator with the same apparatus under constant operating conditions on identical test materials, would, in the long run, and in the normal and correct operation of the test method, exceed the following values only in 1 case in 20:
0.192 x¯
where:
x¯ = denotes mean value.
12.1.2 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, and in the normal and correct operation of the test method, exceed the following values only in one case in 20:
0.332 x¯
where:
x¯ = denotes mean value.
NOTE 11 - Reproducibility with Duplicate Tests - If two successive tests are performed by each operator in 12.1.2, the difference between the averages of the two sets of results from the tests would exceed the following values in one case in 20:
0.302 x¯
where:
x¯ = denotes the mean value of the averaged results from the two laboratories.
If more than two results are obtained by one or both of the laboratories, reproducibility can be calculated as indicated in 4.4 of Practice D3244.
13. Keywords
13.1 acid number; circulating oils; corrosion; hydraulic oils; inhibited steam-turbine oils; iron-coffer catalyst; metal catalyst; oxidation; oxidation lifetime; oxidation stability; test life; turbine oils
