ASTM D2386 standard test method for freezing point of aviation fuels
5. Apparatus
5.1 Jacketed Sample Tube - A double-walled, unsilvered vessel, similar to a Dewar flask, the space between the inner and outer tube walls being filled at atmospheric pressure with dry nitrogen or air. The mouth of the sample tube shall be closed with a stopper supporting the thermometer and moisture-proof collar through which the stirrer passes (Fig. 1).

5.2 Collars - Moisture-proof collars as shown in Fig. 2 shall be used to prevent condensation of moisture.

5.3 Stirrer - Shall be made of 1.6-mm brass rod bent into a smooth three-loop spiral at the bottom.

NOTE 2 - The stirrer may be mechanically actuated as described in the apparatus section of Test Method D3117.

5.4 Vacuum Flask - An unsilvered vacuum flask (Warning - Implosion hazard) having the minimum dimensions shown in Fig. 1 shall be used to hold an adequate volume of cooling liquid and permit the necessary depth of immersion of the jacketed sample tube.

5.5 Thermometer - A total immersion type, having a range from -80 to +20°C, designated as ASTM No. 114C/IP No. 14C. (See Specification E 1, or Appendix A, IP Standard Thermometers, Volume 2, IP Standard Methods for Analysis and Testing of Petroleum and Related Products.)

NOTE 3 - The accuracy of this thermometer is to be checked in accordance with Test Method E 77, at temperatures of 0, -40, -60, and -75°C.

6. Reagents and Materials
6.1 Acetone - Technical Grade acetone is suitable for the cooling bath, provided it does not leave a residue on drying. (Warning - Extremely flammable.)

6.2 Ethanol or Ethyl Alcohol - A commercial or technical grade of dry ethanol is suitable for the cooling bath. (Warning - Extremely flammable.)

6.3 Isopropyl Alcohol - A commercial or technical grade of dry isopropyl alcohol is suitable. (Warning - Extremely flammable.)

6.4 Methanol or Methyl Alcohol - A commercial or technical grade of dry methanol is suitable for the cooling bath. (Warning - Extremely flammable and toxic.)

6.5 Carbon Dioxide (Solid) or Dry Ice - A commercial grade of dry ice is suitable for use in the cooling bath. (See Note 4.) (Warning - Extremely cold, -78°C.)

6.6 Liquid Nitrogen - A commercial or technical grade of liquid nitrogen is suitable for the cooling bath when the freezing point is lower than -65°C. (Warning - Extremely cold, -196°C.)

NOTE 4 - Carbon dioxide (solid) and liquid nitrogen liberate gasses that can cause suffocation. Contact with skin causes burns, freezing, or both.