1、Designation: D 2386 06An American National StandardStandard Test Method forFreezing Point of Aviation Fuels1This standard is issued under the fixed designation D 2386; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of las
2、t revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) 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 determinat
3、ion of the tem-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
4、. No other units of measurement are included in thisstandard.1.3 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-
5、bility of regulatory limitations prior to use. For specificwarning statements, see 5.4, Section 6, and 8.2.2. Referenced Documents2.1 ASTM Standards:2D 910 Specification for Aviation GasolinesD 1655 Specification for Aviation Turbine FuelsD3117 Test Method for WaxAppearance Point of DistillateFuelsD
6、 4057 Practice for Manual Sampling of Petroleum andPetroleum ProductsD 4177 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 Standar
7、ds for Petroleum and Its Products, Part 133. 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 specifi
8、ed conditions of test.4. Significance 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
9、 the aircraft tank normally falls 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 D 910and D 1655.5. Apparatus5.1 Jacketed Sa
10、mple TubeA double-walled, unsilveredvessel, 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 beclosed with a stopper supporting the thermometer andmoisture-proof collar through w
11、hich 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 actuated as described in theappa
12、ratus 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 volume1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products and Lubricants and is t
13、he direct responsibility of SubcommitteeD02.07 on Flow Properties.Current edition approved Jan. 1, 2006. Published February 2006. Originallyapproved in 1965. Last previous edition approved in 2005 as D 238605.This test method has been approved by the sponsoring committees and acceptedby the Cooperat
14、ing Societies in accordance with established procedures.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Avai
15、lable from Energy Institute, 61 New Cavendish St., London, WIG 7AR,U.K.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.of cooling liquid and permit the necessary depth
16、 of immersionof the jacketed sample 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
17、.)NOTE 3The accuracy of this thermometer is to be checked inaccordance with Test Method E77, at temperatures of 0, 40, 60, and75C.46. Reagents and Materials6.1 AcetoneTechnical Grade acetone is suitable for thecooling bath, provided it does not leave a residue on drying.(WarningExtremely flammable.)
18、6.2 Ethanol or Ethyl AlcoholA commercial 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 o
19、r techni-cal grade of dry methanol 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 suffo
20、cation. Contact with skincauses burns, 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 wi
21、th skin causes burns, freezing, or both.)7. Sampling7.1 Obtain a sample in accordance with Practice D 4057 orPractice D 4177.7.2 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.
22、Minimize exposure of the sample to sources of heat.8. Procedure8.1 Measure out 25 6 1 mL of the fuel and transfer 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
23、bulb does nottouch the walls of the tube flask and is approximately in thecenter. The bulb of the thermometer should be 10 to 15 mmfrom the bottom of the sample tube.NOTE 4Performance of this test method can be difficult, since the4The U.S. National Bureau of Standards, Gaithersburg, MD, and the Bri
24、tishNational Physical Laboratory, Teddington, England are able to certify thermometersat these temperatures.FIG. 1 Freezing Point ApparatusD2386062specimen tube is immersed in a coolant medium that evolves gas bubblesduring the test. This can interfere with visual observations. In addition, thecryst
25、als that are formed in the specimen 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
26、should be performed under laboratoryconditions 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 (WarningImpl
27、osion haz-ard) containing the 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 v
28、acuumflask.NOTE 6Acetone and 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. Mechanicalrefrigeratio
29、n is permitted. Where used the 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 andremain below the specimen surface on the
30、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 ofhydrocarbon crystals. Disregard any cloud that appears atapproximately 10C and does not increase in intensity as th
31、etemperature 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 specimen to warm by ambient air, stirring it continuously at1 to 1.5 cycles/s. Continue to observe the specimen continu
32、-ously for the disappearance of hydrocarbon crystals. Recordthe temperature at which the hydrocarbon crystals completelydisappear.NOTEAll dimensions are in mm and 60.1 mm glass wall thickness is 1 mm.FIG. 2 Moistureproof Collars for Freezing Point ApparatusD2386063NOTE 7Because the gases released by
33、 the coolant can obscureobservations, 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
34、,with continued stirring, 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 re
35、commended to compare 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 betwe
36、en these temperatures 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
37、 temperatures, the correction 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 D 2386.NOTE 9When results are desired in degrees Fahrenheit, test resultsobtained in degr
38、ees Celsius should be converted to the nearest wholedegree Fahrenheit. Interim Celsius freezing points should carry the bestprecision available for subsequent conversion to degrees Fahrenheit.10. Precision and Bias510.1 PrecisionThe precision of this test method wasobtained by the statistical examin
39、ation of the results 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 lo
40、ng run, in the normal 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
41、 the normal and correct 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; cryst
42、allizationpoint; determination; 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,D 238605, that may impact the use of this standard. (Appr
43、oved Jan. 1, 2006.)(1) 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,D 238603,
44、that may impact the use 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.ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentioned
45、in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and m
46、ust be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of t
47、heresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C7
48、00, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).5Supporting data have been filed at ASTM International Headquarters and maybe obtained by requesting Research Report RR:D02-1572.D2386064
