ASTM D3228 Test Method for Total Nitrogen In Lubricating Oils and Fuel Oils By Modified Kjeldahl Method
10. Precision and Bias
10.1 Precision:
10.1.1 For Lubricating Oils - The precision of this test method as obtained by statistical examination of interlaboratory test results is as follows:
10.1.1.1 Repeatability - The difference between two 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:
0.01 mass %
10.1.1.2 Reproducibility - The difference between two single and independent results obtained by different operators 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:
0.02 mass %
10.1.2 For Fuel Oils - The precision of this test method as obtained by statistical examination of interlaboratory test results is as follows:
10.1.2.1 Repeatability - The difference between two 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:
0.066 √M
where M = the mean of the values.
10.1.2.2 Reproducibility - The difference between two single and independent results obtained by different operators 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:
0.190 √M
where M = the mean of the two values.
10.2 Bias - Bias has not yet been determined.
11. Keywords
11.1 fuel oils; Kjeldahl; lubricating oils; nitrogen
