ASTM D5846 Universal Oxidation Test for Hydraulic and Turbine Oils
ASTM D5846 Standard Test Method for Universal Oxidation Test for Hydraulic and Turbine Oils Using the Universal Oxidation Test Apparatus
12. Report
12.1 If the test is terminated because of acid number increase, report the oxidation life of the oil as the number of hours to a 0.5 mg KOH/g acid number increase.
12.2 If the test is terminated because of a spot rating of five, report the oxidation life of the oil as the number of hours until the spot was first observed, with (five spot) following the value.
12.3 If the test sample is terminated because of oil depletion and exposure of the catalyst coil above the surface of the oil, report the oxidation life of the oil as greater than the number of hours at which the test was terminated.
12.4 Other qualitative observations, such as color change, formation of sublimate or varnish on the glass, changes in appearance of the catalyst, and so forth, are reported as desired.
13. Precision and Bias
13.1 Precision:
13.1.1 The precision of the test method for oxidation life as obtained by statistical examination of interlaboratory test results is as follows:
13.1.2 Repeatability - The difference between successive 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 one case in 20:
0.0614 X for antiwear hydraulic oils
0.0486 X for steam and gas turbine oils
where X denotes mean value of the oxidation test life, measured in hours to a 0.5 increase in acid number.
13.1.3 Reproducibility - The difference between two single and independent results, obtained by different operators working in different laboratories 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 one case in 20:
0.0918 X for antiwear hydraulic oils
0.1400 X for steam and gas turbine oils
where X denotes mean value of the oxidation test life, measured in hours to a 0.5 increase in acid number.
13.1.4 The precision statement for this test method was determined in two separate round robins. The round robin for antiwear hydraulic oils containing zinc dialkyldithiophosphate used eight new (unused) mineral oil-based lubricants tested by nine cooperators. Oil test life was from 49 to 486 h (raw scores.) The round robin for steam and gas turbine oils used six new (unused) mineral oil-based lubricants tested by five cooperators. The oils covered oxidation lives from 62 to 718 h (raw scores.)
13.2 Bias:
13.2.1 The procedure in this test method has no bias because the value of the oxidation life is defined only in terms of this test method.
14. Keywords
14.1 hydraulic fluids; oxidation stability; turbine oils; universal oxidation test
