ASTM D1321 standard test method for needle penetration of petroleum waxes
9. Report
9.1 Record as a single test value the average scale reading for the four penetrations on the prepared specimen and report to the nearest penetration reading (see 3.1.1). Also report the actual test temperature used.
10. Precision and Bias
10.1 The precision of this test method as determined by statistical examination of interlaboratory results is as follows:
10.1.1 Repeatability - The difference between successive 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 in only one case in twenty.
where:
x = penetration.
10.1.2 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, exceed the following values in only one case in twenty.
where
x = penetration.
10.1.3 The repeatability and reproducibilities for the different penetration values calculated from the above equations are shown in Table 1.
10.2 Bias - The procedure in Test Method D1321 for measuring the needle penetration of petrolatum waxes has no bias because the value of the needle penetration can be defined only in terms of a test method.
11. Keywords
11.1 hardness; needle penetration; penetration; petroleum wax