ASTM D6371 for cold filter plugging point of diesel and heating fuels
13. Report
13.1 Report the temperature read or indicated at the beginning of the last filtration to the nearest 1°C (see 12.1.12, 12.1.16, and 12.2.5) as the CFPP.
13.2 If the specimen has reached -51°C without plugging (see 12.1.15 and 12.2.5) report as "Not plugged at -51°C".
13.3 The report shall contain at least the following information:
13.3.1 The type and identification of the product under test;
13.3.2 A reference to this test method;
13.3.3 The sampling procedure used (see Section 8);
13.3.4 The result of the test (13.1 or 13.2);
13.3.5 Any deviation from the procedure described (see Note 8 and Note 10); and
13.3.6 the date of the test.
14. Precision and Bias
14.1 The precision of this procedure as determined by the statistical examination of the interlaboratory test results is as follows:
14.2 Repeatability - The difference between results obtained on the same day by the same operator with the same apparatus under constant operating conditions on identical test material, would in the long run, with normal and correct operation of the test method, exceed 1.76°C only in one case in twenty.
14.3 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, in the normal and correct operation of the test method, exceed the values indicated by the formula:
0.102 (25-X)°C
where: X is the average of the two results being compared, only in one case in twenty.
NOTE 11 - The interlaboratory test program used to determine the precision of this test method was carried out in 1988 by the IP. The program involved 46 laboratories and 5 samples, ranging in CFPP values from 0°C to -33°C. Extrapolations to measurements more than a few degrees outside this range are unsupported by the data. The raw data from the 1988 program was re-analyzed in 1997 using the ASTM D2PP program. The report of the re-evaluation is available from ASTM Headquarters RR:D02-1452.
14.4 Bias - The procedure in this test method has no bias because the value of CFPP can be defined only in terms of a test method.
14.5 Relative Bias - The current interlaboratory tests confirm that there is no relative bias between the manual and automated apparatuses. Both apparatuses are suitable for reference purposes.
15. Keywords
15.1 automated cold filter plugging point; cold filter plugging point (CFPP); diesel; domestic heating fuels; filterability; manual cold filter plugging point
