ASTM D5985 Test Method for Pour Point of Petroleum Products (Rotational Method)
12. Report
12.1 Report the temperature recorded in 11.8, with resolution of 0.1°C, as the no-flow point in accordance with Test Method D5985 (rotational method).
12.2 Report the temperature recorded in 11.9 as the D97 equivalent pour point in accordance with Test Method D5985.
13. Precision and Bias
13.1 Precision - The precision of this test method as determined by the statistical examination of the interlaboratory test results is as follows:
13.1.1 D97 Equivalent Pour Point (Rotational Method):
13.1.1.1 Repeatability - The difference between successive test results, obtained by the same operator using the same apparatus under constant operating conditions on identical test material, would in the long run, in the normal and correct operation of this test method, exceed the following only in one case in twenty.
2.3°C
13.1.1.2 Reproducibility - The difference between two single and independent test results, obtained by different operators working in different laboratories on identical test material, would in the long run, in normal and correct operation of this test method, exceed the following only in one case in twenty.
8.7°C
13.1.2 No-Flow Point - Repeatability - The difference between successive test results, obtained by the same operator using the same apparatus under constant operating conditions on identical test material, would in the long run, in the normal and correct operation of this test method, exceed the following only in one case in twenty.
1.18°C
13.2 Bias - Since there is no accepted reference material suitable for determining the bias for the procedure in this test method, bias has not been determined.
13.3 Relative Bias - Relative bias among certain samples, was observed when the D97/IP15 equivalent pour point results were compared to the results from Test Method D97. The observed bias does not appear to be of a systematic nature and is within the reproducibility of either test method. Bias relative to Test Method D97 may conceivably occur for sample types not included in the interlaboratory program. When a new formulation or sample type is encountered, the performance of this test method shall be compared to Test Method D97 before reporting results as Test Method D97 equivalent.
13.4 The precision statements in 13.1.1 were derived from the 1992 interlaboratory test program. Participants analyzed three sets of duplicate fuel oils and six sets of duplicate lubricating oils in the temperature range of + 6 to -39°C. Six laboratories participated with the automatic apparatus and seven laboratories participated with the manual Test Method D97 apparatus. Information on the types of samples and their average pour points are in the research report available from ASTM Headquarters.
13.5 The precision statements in 13.1.2 were derived from the 0.1°C resolution data obtained from two within-one-laboratory test programs. The first program in 1984 consisted of twelve sets of duplicate lubricating oils and fuel oils, and fourteen sets of duplicate fuel oils in the temperature range from + 51 to -51°C. The second was part of the 1992 interlaboratory program where one laboratory submitted 0.1°C resolution data along with the calculated 3°C results on the same samples. The repeatability is calculated using the program described in RR:D2-1007 on the results obtained from the 1984 program which was the worst case of the two programs. This data does not meet ASTM criteria for RR:D02-1007.
14. Keywords
14.1 D97 equivalent; petroleum products; pour point; rotational pour point
