1、Designation: D2386 06 (Reapproved 2012)Standard Test Method forFreezing Point of Aviation Fuels1This standard is issued under the fixed designation D2386; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A
2、 number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the Department of Defense.1. Scope*1.1 This test method covers the determination of the tem
3、-perature below which solid hydrocarbon crystals may form inaviation turbine fuels and aviation gasoline.NOTE 1The interlaboratory program that generated the precisions forthis test method did not include aviation gasoline.1.2 The values stated in SI units are to be regarded asstandard. No other uni
4、ts of measurement are included in thisstandard.1.3 WARNINGMercury has been designated by manyregulatory agencies as a hazardous material that can causecentral nervous system, kidney and liver damage. Mercury, orits vapor, may be hazardous to health and corrosive tomaterials. Caution should be taken
5、when handling mercury andmercury containing products. See the applicable product Ma-terial Safety Data Sheet (MSDS) for details and EPAswebsitehttp:/www.epa.gov/mercury/faq.htmfor addi-tional information. Users should be aware that selling mercuryand/or mercury containing products into your state or
6、 countrymay be prohibited by law.1.4 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitat
7、ions prior to use. For specificwarning statements, see 5.4, Section 6, and 8.2.2. Referenced Documents2.1 ASTM Standards:2D910 Specification for Aviation GasolinesD1655 Specification for Aviation Turbine FuelsD3117 Test Method for Wax Appearance Point of DistillateFuels3D4057 Practice for Manual Sam
8、pling of Petroleum andPetroleum ProductsD4177 Practice for Automatic Sampling of Petroleum andPetroleum ProductsE1 Specification for ASTM Liquid-in-Glass ThermometersE77 Test Method for Inspection and Verification of Ther-mometers2.2 Energy Institute Standard:IP Standards for Petroleum and Its Produ
9、cts, Part 143. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 freezing point, nin aviation fuels, the fuel tempera-ture at which solid hydrocarbon crystals, formed on cooling,disappear when the temperature of the fuel is allowed to riseunder specified conditions of test.4. Signi
10、ficance and Use4.1 The freezing point of an aviation fuel is the lowesttemperature at which the fuel remains free of solid hydrocar-bon crystals that can restrict the flow of fuel through filters ifpresent in the fuel system of the aircraft.The temperature of thefuel in the aircraft tank normally fa
11、lls during flight dependingon aircraft speed, altitude, and flight duration. The freezingpoint of the fuel must always be lower than the minimumoperational tank temperature.4.2 Freezing point is a requirement in Specifications D910and D1655.5. Apparatus5.1 Jacketed Sample TubeA double-walled, unsilv
12、eredvessel, similar to a Dewar flask, the space between the innerand outer tube walls being filled at atmospheric pressure withdry nitrogen or air. The mouth of the sample tube shall be1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products and Lubricants and is the di
13、rect responsibility of SubcommitteeD02.07 on Flow Properties.Current edition approved April 15, 2012. Published April 2012. Originallyapproved in 1965. Last previous edition approved in 2006 as D238606. DOI:10.1520/D2386-06R12.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orc
14、ontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Withdrawn. The last approved version of this historical standard is referencedon www.astm.org.4Available from Energy Institute, 61 Ne
15、w Cavendish St., London, WIG 7AR,U.K., http:/www.energyinst.org.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.closed with a stopper supporting the thermometer andmoi
16、sture-proof collar through which the stirrer passes (Fig. 1).5.2 CollarsMoisture-proof collars as shown in Fig. 2shall be used to prevent condensation of moisture.5.3 StirrerShall be made of 1.6-mm brass rod bent into asmooth three-loop spiral at the bottom.NOTE 2The stirrer may be mechanically actu
17、ated as described in theapparatus section of Test Method D3117.5.4 Vacuum FlaskAn unsilvered vacuum flask(WarningImplosion hazard) having the minimum dimen-sions shown in Fig. 1 shall be used to hold an adequate volumeof cooling liquid and permit the necessary depth of immersionof the jacketed sampl
18、e tube.5.5 ThermometerA total immersion type, having a rangefrom 80 to +20C, designated as ASTM No. 114C/IP No.14C. (See Specification E1, or Appendix A, IP StandardThermometers, Volume 2, IP Standard Methods for Analysisand Testing of Petroleum and Related Products.)NOTE 3The accuracy of this therm
19、ometer is to be checked inaccordance with Test Method E77, at temperatures of 0, 40, 60, and75C.56. Reagents and Materials6.1 AcetoneTechnical Grade acetone is suitable for thecooling bath, provided it does not leave a residue on drying.(WarningExtremely flammable.)6.2 Ethanol or Ethyl AlcoholA comm
20、ercial or technicalgrade of dry ethanol is suitable for the cooling bath.(WarningExtremely flammable.)6.3 Isopropyl AlcoholA commercial or technical grade ofdry isopropyl alcohol is suitable. (WarningExtremely flam-mable.)6.4 Methanol or Methyl AlcoholA commercial or techni-cal grade of dry methanol
21、 is suitable for the cooling bath.(WarningExtremely flammable and toxic.)6.5 Carbon Dioxide (Solid) or Dry IceA commercialgrade of dry ice is suitable for use in the cooling bath.(WarningExtremely cold, 78C. Carbon dioxide (solid)liberates gases that can cause suffocation. Contact with skincauses bu
22、rns, freezing, or both.)6.6 Liquid NitrogenA commercial or technical grade ofliquid nitrogen is suitable for the cooling bath when thefreezing point is lower than 65C. (WarningExtremelycold, 196C. Liquid nitrogen liberates gases that can causesuffocation. Contact with skin causes burns, freezing, or
23、 both.)7. Sampling7.1 Obtain a sample in accordance with Practice D4057 orPractice D4177.5The U.S. National Bureau of Standards, Gaithersburg, MD, and the BritishNational Physical Laboratory, Teddington, England are able to certify thermometersat these temperatures.FIG. 1 Freezing Point ApparatusD23
24、86 06 (2012)27.2 At least 25 mL of specimen is required for each test.7.3 Keep the sample in a tightly sealed container at ambientroom temperature to minimize introduction of any moisture.Minimize exposure of the sample to sources of heat.8. Procedure8.1 Measure out 25 6 1 mL of the fuel and transfe
25、r it to theclean, dry, jacketed sample tube. Close the tube tightly with thecork holding the stirrer, thermometer, and moisture proof collarand adjust the thermometer position so that its bulb does nottouch the walls of the tube flask and is approximately in thecenter. The bulb of the thermometer sh
26、ould be 10 to 15 mmfrom the bottom of the sample tube.NOTE 4Performance of this test method can be difficult, since thespecimen tube is immersed in a coolant medium that evolves gas bubblesduring the test. This can interfere with visual observations. In addition, thecrystals that are formed in the s
27、pecimen can be difficult to recognize, andthey can appear in a variety of manifestations. It is strongly suggested thatoperators seek guidance from experienced operators of this test method toassist them in the correct recognition of these crystals.NOTE 5This test method should be performed under la
28、boratoryconditions where there is an ample supply of light. Some crystals can bevery faint in appearance and difficult to observe under inadequate lightingconditions.8.2 Clamp the jacketed sample tube so that it extends as faras possible into the vacuum flask (WarningImplosion haz-ard) containing th
29、e cooling medium (Note 6). The surface ofthe sample should be approximately 15 to 20 mm below thelevel of the coolant. Unless the medium is cooled by mechani-cal refrigeration, add solid carbon dioxide as necessarythroughout the test to maintain the coolant level in the vacuumflask.NOTE 6Acetone and
30、 either methyl, ethyl, or isopropyl alcohols aresuitable. All of these require cautious handling. Liquid nitrogen may alsobe used as a coolant instead of liquids cooled with solid carbon dioxide forfuel samples which have a freezing point below 65C. Mechanicalrefrigeration is permitted. Where used t
31、he refrigerant temperature shouldbe 70C to 80C.8.3 Stir the fuel continuously, moving the stirrer up anddown at the rate of 1 to 1.5 cycles/s, taking care that the stirrerloops approach the bottom of the flask on the downstroke andNOTEAll dimensions are in mm and 60.1 mm glass wall thickness is 1 mm
32、.FIG. 2 Moistureproof Collars for Freezing Point ApparatusD2386 06 (2012)3remain below the specimen surface on the upstroke. It ispermissible for momentary interruption of stirring while per-forming some operations of the procedure (see Note 7).Observe the specimen continuously for the appearance of
33、hydrocarbon crystals. Disregard any cloud that appears atapproximately 10C and does not increase in intensity as thetemperature decreases, because this cloud is due to water.Record the temperature at which hydrocarbon crystals appear.Remove the jacketed sample tube from the coolant and allowthe spec
34、imen to warm by ambient air, stirring it continuously at1 to 1.5 cycles/s. Continue to observe the specimen continu-ously for the disappearance of hydrocarbon crystals. Recordthe temperature at which the hydrocarbon crystals completelydisappear.NOTE 7Because the gases released by the coolant can obs
35、cureobservations, the sample tube can be removed from the coolant forobservations. The tube can be removed for periods no longer than 10 s. Ifcrystals are observed to have already formed, the specimen temperatureshould be noted and the specimen allowed to be warmed by ambient air,with continued stir
36、ring, to at least 5C above the temperature at which thecrystals disappear. The specimen should then be re-immersed in thecoolant and allowed to cool. Remove the specimen from the coolantslightly above the noted temperature, and observe for appearance of thecrystals.NOTE 8It is recommended to compare
37、 the crystal appearance tem-perature with the crystal disappearance temperature. The appearancetemperature should be colder than the disappearance temperature. If this isnot the case, this is an indication that the crystals were not correctlyrecognized. Also, the difference between these temperature
38、s shouldtypically be no greater than 6C.9. Report9.1 The observed freezing point determined in Section 8shall be corrected by applying the relevant thermometercorrection resulting from the checks described in Note 3.Where the observed freezing point falls between two calibra-tion temperatures, the c
39、orrection at the observed temperatureshall be obtained by linear interpolation. Report the correctedtemperature of crystal disappearance to the nearest 0.5C as thefreezing point, Test Method D2386.NOTE 9When results are desired in degrees Fahrenheit, test resultsobtained in degrees Celsius should be
40、 converted to the nearest wholedegree Fahrenheit. Interim Celsius freezing points should carry the bestprecision available for subsequent conversion to degrees Fahrenheit.10. Precision and Bias610.1 PrecisionThe precision of this test method wasobtained by the statistical examination of the results
41、of 13samples of fuel consisting of JetA, JetA1, JP-5 and JP-8 testedby 15 laboratories.10.1.1 RepeatabilityThe difference between two test re-sults obtained by the same operator with the same apparatusunder constant operating conditions on identical test materialwould, in the long run, in the normal
42、 and correct operation ofthe test method, exceed 1.5C only in one case in twenty.10.1.2 ReproducibilityThe difference between two singleand independent results obtained by different operators work-ing in different laboratories on identical test material would, inthe long run, in the normal and corre
43、ct operation of the testmethod, exceed 2.5C only in one case in twenty.10.2 BiasBecause there are no liquid hydrocarbon mix-tures of “known” freezing point, which simulate aviation fuels,bias cannot be established.11. Keywords11.1 aviation gasoline; aviation turbine fuels; crystallizationpoint; dete
44、rmination; freezing point; low temperature tests;manual method; petroleum products; physical testsSUMMARY OF CHANGESSubcommittee D02.07 has identified the location of selected changes to this standard since the last issue,D238605, that may impact the use of this standard. (Approved Jan. 1, 2006.)(1)
45、 Revised Note 7.(2) Revised 8.3 to clarify continuous stirring and observations.(3) Added Note 8.(4) Added Section 7.(5) Renumbered sections and notes throughout.Subcommittee D02.07 has identified the location of selected changes to this standard since the last issue,D238603, that may impact the use
46、 of this standard. (Approved July 1, 2005.)(1) Section 10 has been updated to reflect precision and biasdata reported in Research Report RR:D02-1572.6Supporting data have been filed at ASTM International Headquarters and maybe obtained by requesting Research Report RR:D02-1572.D2386 06 (2012)4ASTM I
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