ISO 3104 Petroleum products - Transparent and opaque liquids - Determination of kinematic viscosity and calculation of dynamic viscosity
13 Expression of results
Report the test results for kinematic viscosity and/or dynamic viscosity to four significant figures, together with the test temperature.

14 Precision
14.1 Determinability (d)
The difference between successive determinations obtained by the same operator in the same laboratory using the same apparatus for a series of operations leading to a single result, would in the long run, in the normal and correct operation of this test method, exceed the values indicated below only in one case in twenty:
Base oils at 40°C and 100°C
0.0020y (0.20 %)

Formulated oils at 40°C and 100°C
0.0013y (0.13 %)

Formulated oils at 150°C
0.015y (1.5 %)

Petroleum wax at 100°C
0.0080y (0.80 %)

Residual fuel oils at 80°C and 100°C
0.011 (y + 8)

Residual fuel oils at 50°C
0.017y (1.7 %)

where y is the average of determinations being compared.

14.2 Repeatability (r)
The difference between successive results obtained by the same operator with the same apparatus under constant operating conditions on identical test maerial would, in the long run, in the normal and correct operation of this test method, exceed the values indicated below only in one case in twenty:
Base oils at 40°C and 100°C
0.0011x (0.11 %)

Formulated oils at 40°C and 100°C
0.0026x (0.26 %)

Formulated oils at 150°C
0.0056x (0.56 %)

Petroleum wax at 100°C
0.0141x

Residual fuel oils at 80°C and 100°C
0.013(x + 8)

Residual fuel oils at 50°C
0.015x (1.5 %)

where x is the average of results being compared.

1 4.3 Reproducibility (R)
The difference between two single and independent results obtained by different operators working in different laboratories on nominally identical test material would, in the long run, in the normal and correct operation of this test method, exceed the values indicated below only in one case in twenty:
Base oils at 40°C and 100°C
0.0065x (0.65 %)

Formulated oils at 40°C and 100°C
0.0076x (0.76 %)

Formulated oils at 150°C
0.018x (1.8 %)

Petroleum wax at 100°C
0.0366x

Residual fuel oils at 80°C and 100°C
0.04(x + 8)

Residual fuel oils at 50°C
0.074x (7.4 %)

where x is the average of results being compared.

NOTE 21 The precision for used oils has not been determined but is expected to be poorer than that for formulated oils. Because of the extreme variability of such used oils, it is not anticipated that the precision of used oils will be determined.

15 Test report
The test report shall contain at least the following information:
a) sufficient details for complete identification of the product tested;
b) a reference to this International Standard or a corresponding national standard;
c) the result of the test (see clause 13);
d) any deviation, by agreement or otherwise, from procedure specified;
e) the date of the test;
f) the name and address of the test laboratory.