5.1?The freezing point of an aviation fuel is an index of the lowest temperature of its utility for certain applications. Solid hydrocarbon crystals can restrict the flow of fuel in the fuel system of the aircraft. The temperature of the fuel in the aircraft tank normally decreases during flight depending on aircraft speed, altitude, and flight duration. The freezing point of the fuel must always be lower than the minimum operational fuel temperature.

5.2?Petroleum blending operations require precise measurement of the freezing point.

5.3?This test method expresses results with a resolution of 0.1 ?C.

5.4?This test method eliminates most of the operator time and judgment required by Test Method D2386.

5.5?When the specification requires the use of Test Method D2386, do not substitute this test method or any other method.

1.1?This test method covers the determination of the temperature below which solid hydrocarbon crystals may form in aviation turbine fuels.

1.2?The measuring range of the apparatus is from 70 ?C to 0 ?C, however the precision statements were derived only from samples with freezing point temperatures from 60 ?C to 42 ?C.

1.3?Some results from this test method (14 % of samples included in the 2003 round robin2) incorrectly identified sample contamination where no contaminants were present in the samples (see research report2 for further information).

1.4?The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.

1.5?This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. For specific hazard statements, see Section 7.

1.6?This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.