ASTM D4421 Standard Test Method for Volatile Matter in Petroleum Coke
11. Calculations
11.1 Calculate the volatile matter of the moisture free prepared coke as follows:
Volatile matter, mass % = (A/B) x 100
where:
A = mass loss of the sample, g, and
B = mass of sample, g.
12. Precision and Bias
12.1 The precision of this test method as determined by the statistical examination of interlaboratory test results is as follows:
12.1.1 Repeatability - The difference between successive results by the same operator using the same apparatus under constant operating conditions on identical test materials will in the long run, in normal and correct operation of the test method, exceed the following values only in one case in twenty:
Repeatability = 0.08 (X)
where X is the average of two results in weight percent.
12.1.2 Reproducibility - The difference between two single and independent results obtained by different operators working in different laboratories on identical test materials, will, in the long run, in normal and correct operation of the test method, exceed the following values only in one case in twenty:
Reproducibility = 0.21 (X)
where X = the average of two results in mass percent.
12.1.3 Bias - The test is empirical, therefore, the results are dependent on the material, on the particulate composition of the sample and on the manner of the test. Bias is not a definable constituent outside this test. Therefore, no statement of accuracy is possible.
13. Keywords
13.1 petroleum coke; volatile matter
