ASTM D5481 Standard Test Method for Measuring Apparent Viscosity at High-Temperature and High-Shear Rate by Multicell Capillary Viscometer
12. Report
12.1 Report the viscosity in millipascal seconds (mPa•s) to two decimal places and the test temperature (°C).
13. Precision and Bias
13.1 The precision of the test method was determined by the statistical examination of interlaboratory test results. The precision calculated from the test results is as follows:
13.1.1 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 value in only one case in twenty:
Repeatability = 1.6 % of the mean
13.1.2 The difference between successive results obtained by different operators working in different laboratories on identical test materials would, in the long run, in the normal and correct operation of the test method, exceed the following value in only one case in twenty:
Reproducibility = 5.4 % of the mean
13.2 Bias - This test method uses standards of known viscosity to establish a calibration curve which is then used to determine the viscosities of test oils by interpolation. The standards are thereby forced to their correct valves. As a result of this relative method of determining viscosities, this test method has no bias.
13.3 Relative Bias - Results from this test method were found, in an interlaboratory study, to agree with those from Test Methods D4683 and D4741. They can be expected to give, on average in the long run, the same results for the same oil.
14. Keywords
14.1 capillary method; shear testing-petroleum products; viscosity; viscosity-apparent
