Chapter 5 - Ground Crew Supplement

Freezing Point

23.  The freezing points are determined by the American Society for Testing Materials (ASTM) D 1177 method, which measure the temperature of the first ice crystal formation.

24.  Frequent determinations of the freezing point of fluids are required to ensure that the desired freezing point is maintained.

25.  As the concentration of the fluid is increased from 0% upwards, by volume, the freezing point decreases. At some point as the concentration is increased towards 100%, the freezing point starts to increase. The reason for this tendency is that a solution has a lower freezing point than a pure solvent.