11. Calculation
11.1 Calculate the carbon residue of the sample or of the 10 % distillation residue as follows:
Carbon residue = (A x 100)/W
where:
A = mass of carbon residue, g, and
W = mass of sample, g.
12. Report
12.1 Report the value obtained as Conradson Carbon Residue, percent or as Conradson Carbon Residue on 10 % distillation residue, percent, Test Method D 189.
13. Precision and Bias
13.1 The precision of this test method as determined by statistical examination of interlaboratory results is as follows:
13.1.1 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 values shown in Fig. 2 only in one case in twenty.
13.1.2 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 values shown in Fig. 2 only in one case in twenty.
NOTE 6 - Precision is based on data developed using inch-pound units. See Test Method D 189–76.
13.2 Bias - This test method is based on empirical results and no statement of bias can be made.
14. Keywords
14.1 Conradson carbon residue; lubricants; petroleum products
