ASTM D4422 Standard Test Method for Ash in Analysis of Petroleum Coke
11. Report
11.1 Report the ash content mass percent to the third decimal (thousandth of a percent) when the average of replicate values permits.
11.2 Report the ash content mass percent to the second decimal (hundredth of a percent) when only single values are determined.
12. Precision and Bias
12.1 Precision - The precision of this test method as determined by the statistical examination of the interlaboratory test results is as follows:
12.1.1 Repeatability - The difference between successive results obtained by the same operator with the same apparatus under constant operating conditions on identical test materials 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 = 0.02
12.1.2 Reproducibility - The difference between two single and independent results obtained by different operators working in different laboratories on identical material would in the long run, exceed the following values only in one case in twenty.
Reproducibility = 0.06
12.2 Bias - Bias depends on conformance to the empirical conditions of the test. The ash content must not be understood to be the same as the mineral content of the petroleum coke.
13. Keywords
13.1 ash; petroleum coke
