14. Precision and Bias
14.1 Precision - The precision of this test method as determined by the statistical examination of the interlaboratory test results is as follows:
14.1.1 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 1 case in 20.
Flash point 8°C (15°F)
Fire point 8°C (15°F)

14.1.2 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, in the normal and correct operation of the test method, exceed the following values only in one case in 20.
Flash point 18°C (32°F)
Fire point 14°C (25°F)

14.2 The precision data for fire point is not known to have been developed in accordance with Precision Manual RR:D02-1007.

NOTE 21 - The precisions for fire point were not determined in the current interlaboratory program. Fire point is a parameter that is not commonly specified, although in some cases, this temperature may be desired.

NOTE 22 - The precision for asphalt type samples which have had any formed surface film removed has not been determined.

NOTE 23 - The precision for asphalt type samples which have utilized the procedure in Appendix X1 have not been determined.

14.3 Bias - The procedure of this test method has no bias because flash point and fire point can be defined only in terms of this test method.

14.4 Relative Bias - Statistical evaluation of the data did not detect any significant difference between the reproducibility variances of manual and automated Cleveland flash point results for the samples studied with the exception of multi-viscosity lubricating oil and white mineral oil. Evaluation of the data did not detect any significant difference between averages of manual and automated Cleveland flash point for the samples studied with the exception of multi-viscosity lubricating oil, which showed some bias. In any case of dispute, the flash point as determined by the manual procedure shall be considered the referee test.

14.5 The precision data for flash point were developed in a 1991 cooperative test program using seven samples of base oils, asphalt, and lubricating oils. Five laboratories participated with the manual apparatus and eight laboratories participated with the automated equipment. Information on the type of samples and their average flash point are in the research report available at ASTM Headquarters.

15. Keywords
15.1 automated Cleveland open cup; Cleveland open cup; fire point open cup for flash point; flammability; flash point; petroleum products