ASTM D1177 Test Method for Freezing Point of Aqueous Engine Coolants
9. Report
9.1 Plot the observed temperature against time on rectangular coordinate paper. Where the curve shows a definite flat or plateau during freezing, the freezing point is taken as the intersection of projections of the cooling curve and the flat or horizontal plateau portion of the freezing curve (see Fig. 3(a)). If the solution supercools, the freezing point is the maximum temperature reached immediately after supercooling (see Fig. 3(b)).
NOTE 9 - The amount of supercooling should be held to a minimum. If the supercooling exceeds 1°C (2°F) the test should be rejected.
10. Precision and Bias
10.1 Precision - The precision of this test method, as determined by the examination of the interlaboratory test results, is as follows:
10.1.1 Repeatability - Results obtained by one operator and one apparatus should not differ from the mean by more than ±0.3°C (±0.5°F).
10.1.2 Reproducibility - Results obtained by different operators and different apparatuses should not differ from the mean by more than ±0.6°C (±1.0°F).
10.2 Bias - Since there is no acceptable reference material suitable for determining the bias for the procedure in this test method bias has not been determined.
11. Keywords
11.1 aqueous engine coolants; engine coolants; freezing point
