1、Designation: D 7154 05IP 528An American National StandardStandard Test Method forFreezing Point of Aviation Fuels (Automatic Fiber OpticalMethod)1This standard is issued under the fixed designation D 7154; the number immediately following the designation indicates the year oforiginal adoption or, in
2、 the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.INTRODUCTIONThis test method is nearly identical to Test Method D 5901. The difference in this
3、 test method is theversion of software (version V.22) that is utilized in the apparatus. This version of software is intendedto better identify samples that are contaminated. Since the algorithm in this version of software isdifferent than previous versions utilized in this apparatus, the subcommitt
4、ee determined to publish aseparate test method with a different standard designation.1. Scope1.1 This test method covers the determination of the tem-perature below which solid hydrocarbon crystals may form inaviation turbine fuels.NOTE 1This test method describes an alternative procedure andautomat
5、ic apparatus which closely mimics the apparatus and proceduredescribed in Test Method D 2386.1.2 The measuring range of the apparatus is from -70 to0C, however the precision statements were derived only fromsamples with freezing point temperatures from -60 to -42C.NOTE 2Typical aviation fuel has fre
6、ezing point temperatures in the-60 to -40C range.1.3 Some results from this test method (14% of samplesincluded in the 2003 round robin2) incorrectly identifiedsample contamination where no contaminants were present inthe samples (see research report2for further information).1.4 The values stated in
7、 SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.5 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 heal
8、th practices and determine the applica-bility of regulatory limitations prior to use. For specific hazardstatements, see Section 7.2. Referenced Documents2.1 ASTM Standards:3D 2386 Test Method for Freezing Point of Aviation FuelsD 4057 Practice for Manual Sampling of Petroleum andPetroleum ProductsD
9、 4177 Practice for Automatic Sampling of Petroleum andPetroleum ProductsD 5901 Test Method for Freezing Point of Aviation Fuels(Automated Optical Method)D 6708 Practice for Statistical Assessment and Improve-ment of the Expected Agreement Between Two TestMethods that Purport to Measure the Same Prop
10、erty of aMaterialE1 Specification for ASTM Liquid-in-Glass Thermometers2.2 Energy Institute Standard:IP 16 Determination Freezing Point of Aviation Fuels3. Terminology3.1 Definitions:3.1.1 freezing point, nin aviation fuels, the fuel tempera-ture at which solid hydrocarbon crystals, formed on coolin
11、g,disappear when the temperature of the fuel is allowed to riseunder specified conditions of test.1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products and Lubricants and is the direct responsibility of SubcommitteeD02.07 on Flow Properties.Current edition approved J
12、uly 1, 2005. Published July 2005.2Supporting data (2003 Interlaboratory Cooperative Test Program) have beenfiled at ASTM International Headquarters and may be obtained by requestingResearch Report RR:D02-1572.3For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Custom
13、er Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.3.2 Definitions of Terms Specific to
14、This Standard:3.2.1 automatic fiber optical method, nthe robotic auto-mation of a manual procedure and apparatus and use of fiberoptics to transmit crystal detection signals to and from thespecimen test chamber.4. Summary of Test Method4.1 After insertion of 25 mL of the test specimen into a testcha
15、mber, the test specimen is cooled while being continuouslystirred and monitored by a fiber optical system. The tempera-ture of the specimen is measured with an electronic tempera-ture measuring device. When crystal formation is detected inthe specimen, the temperature is recorded and the specimen in
16、the test chamber is warmed, while being continuously stirredand monitored by the optical system, until the crystals in thespecimen completely disappear. The temperature of the speci-men when the last crystals disappear is recorded as the freezingpoint (automatic fiber optical method).5. Significance
17、 and Use5.1 The freezing point of an aviation fuel is an index of thelowest temperature of its utility for certain applications. Solidhydrocarbon crystals can restrict the flow of fuel in the fuelsystem of the aircraft. The temperature of the fuel in the aircrafttank normally decreases during flight
18、 depending on aircraftspeed, altitude, and flight duration. The freezing point of thefuel must always be lower than the minimum operational fueltemperature.5.2 Petroleum blending operations require precise measure-ment of the freezing point.5.3 This test method expresses results with a resolution of
19、0.1C.5.4 This test method eliminates most of the operator timeand judgment required by Test Method D 2386.5.5 When the specification requires the use of Test MethodD 2386, do not substitute this test method or any other method.6. Apparatus (see Annex A1)6.1 Automatic Fiber Optical Apparatus4The appa
20、ratus asdescribed in Annex A1 shall consist of a test chamber com-prising a jacketed test tube supported in a jacketed enclosureconfiguration that is capable of cooling and heating the testspecimen to the temperatures required in the test. The appara-tus shall have a nitrogen purge collar as part of
21、 the closureassembly for the test chamber, which prevents moisture fromcombining with the test specimen. The apparatus shall becapable of measuring the temperature of the test specimen,continuously stirring the test specimen at the prescribed rate,automatically cooling and then heating the test spec
22、imen,monitoring the test specimen with an electronic optical systemfor appearance and disappearance of the crystals in the testspecimen under the conditions of the test, and recording theappearance and disappearance temperatures.6.2 Circulating Bath, refrigeration unit equipped with acirculating pum
23、p capable of maintaining the temperature of aquantity of methyl alcohol at least 20C lower than theminimum test specimen temperature expected.NOTE 3To achieve a typical test chamber cooling condition of -75C,the circulating bath should be capable of achieving -85 to -90C, sinceapproximately 5 to 10C
24、 is consumed in the circulation lines andinsulation.6.3 Instrument and Software VersionThe HCP 860 appa-ratus with V.22 software was used in the 2003 InterlaboratoryProgram2that determined the precision and relative bias inSection 13.7. Reagents and Materials7.1 Cooling Medium, Methyl AlcoholA comme
25、rcial ortechnical grade of anhydrous methanol is suitable for use as thecooling medium. (WarningExtremely flammable. Toxic.May be fatal or cause blindness if swallowed or inhaled.)7.2 Nitrogen Gas, dry nitrogen gas which has a dew pointbelow the lowest temperature expected to be attained by thetest
26、specimen under the conditions of the test. (WarningCompressed gas under high pressure. Inert gas can be anasphyxiant when inhaled.)7.3 Cleaning Solvents, suitable for cleaning and drying thetest chamber, such as petroleum naphtha and methyl alcohol.(WarningFlammable. Liquid causes eye burns. Vapor h
27、arm-ful. Toxic. May be fatal or cause blindness if swallowed orinhaled.)8. Sampling8.1 Obtain a sample in accordance with Practice D 4057 orD 4177.8.2 At least 25 mL of sample is required for each test. Referto Practice D 4057.9. Preparation of Apparatus9.1 Prepare the apparatus for operation in acc
28、ordance withthe manufacturers instructions.9.2 Clean and dry the test chamber with petroleum naphthato rinse out any previous specimen followed by a second rinseof alcohol to remove naphtha. Dry with moisture-free air orgas. Ensure that moisture does not remain inside the testchamber.9.3 Prepare the
29、 refrigerated circulating bath for operation inaccordance with the manufacturers instructions and allow it toattain a temperature lower than -75C. The temperature of thealcohol, at the test chamber, shall not be below -80C unlessthe expected freezing point is below -60C.9.4 Confirm that the supply o
30、f nitrogen purge gas is con-nected and regulated in accordance with the manufacturersinstructions.10. Calibration and Standardization10.1 Ensure that all of the manufacturers instructions forcalibrating, checking, and operating the apparatus are followedincluding calibration of the temperature measu
31、ring systemagainst a certified standard temperature device.4The sole source of supply of the apparatus known to the committee at this timeis Herzog model HCP 860 Freezing Point Analyzer with software version V.22,available from Walter Herzog, Lauda, Germany. If you are aware of alternativesuppliers,
32、 please provide this information to ASTM International Headquarters.Your comments will receive careful consideration at a meeting of the responsibletechnical committee,1which you may attend.D715405210.2 A sample with a mutually agreed upon freezing pointsuch as one from an interlaboratory test progr
33、am, Test MethodD 2386 or equivalent, can be used to verify performance of theapparatus within the precisions of this test method.11. Procedure11.1 Measure out 25 6 1 mL of the fuel, and transfer it tothe clean, dry, test chamber. Support the test chamber in theposition recommended by the manufacture
34、r, enclosing the topof the test chamber with a closure assembly supporting thestirrer, temperature measuring device, optical system, andnitrogen purge collar. Adjust the temperature measuring deviceposition, if necessary, so that it is positioned in the center of thetest chamber. Ensure that the bot
35、tom of the temperaturemeasuring device is between 35 to 45 mm from the bottom ofthe test chamber. Connect the cooling medium inlet and outlethoses to the respective connections on the test chamberaccording to the manufacturers instructions.11.2 Start the operation of the apparatus according to thema
36、nufacturers instructions. This shall enable the flow of thecooling medium for cooling of the specimen, the flow of thepurge gas, and the stirring of the specimen continuously andwithout interruption. The stirrer shall move up and downvertically at the rate of 1 to 1.5 cycles per second, taking caret
37、hat the stirrer loops approach the bottom of the test chamberon the downstroke and remain below the specimen surface onthe upstroke.11.3 The fiber optical system shall monitor the specimen forthe appearance of hydrocarbon crystals. The apparatus shalldisregard any cloud-like formation, due to water,
38、 that appearsin the test specimen at approximately -10C and does notincrease in intensity as the specimen temperature decreases.11.4 After the crystals are detected, the apparatus shalldiscontinue the flow of the cooling medium. Allow the testspecimen to warm by circulating nitrogen gas in place of
39、thecooling medium. The apparatus shall continue the stirring ofthe specimen in the prescribed manner.11.5 The fiber optical system shall continue to monitor thehydrocarbon crystals in the specimen and the apparatus shallrecord the temperature when the crystals completely disappear.11.6 After the hyd
40、rocarbon crystals have disappeared, theapparatus shall discontinue the stirring and the warmingmedium.11.7 Remove the test chamber from the apparatus and cleanand dry according to the manufacturers instructions.12. Report12.1 Report the temperature of crystal disappearance re-corded in 11.5 to the n
41、earest 0.1C as the freezing point, TestMethod D 7154.13. Precision and Bias13.1 PrecisionThe precision of this test method as deter-mined by the statistical examination of the interlaboratory2testresults is as follows:13.1.1 RepeatabilityThe difference between two resultsobtained by the same operato
42、r with the same apparatus underconstant operating conditions on identical test material would,in the long run, in the normal and correct operation of this testmethod, exceed 0.5C only in one case in twenty.13.1.2 ReproducibilityThe difference between two singleand independent results obtained by dif
43、ferent operators work-ing in different laboratories on identical test material would, inthe long run, in the normal and correct operation of this testmethod, exceed 1.9C only in one case in twenty.13.2 BiasBecause there are no liquid hydrocarbon mix-tures of known freezing point, which simulate avia
44、tion fuels,bias cannot be established.13.3 Relative BiasThe degree of agreement between thistest method and Test Method D 2386 from the 2003 interlabo-ratory program cited has been performed in accordance withPractice D 6708. No relative bias was observed. The crossmethod reproducibility (Rxy) ident
45、ified in the research report2between this test method and Test Method D 2386 is 2.2.13.4 The precision statements were derived from a 2003interlaboratory cooperative test program.2Participants ana-lyzed 13 samples sets comprised of various aviation fuels overthe temperature range of -60 to -42C. Ele
46、ven laboratoriesparticipated with the automatic fiber optical method and fifteenwith the manual Test Method D 2386 or IP 16 test methods.The precision statistics were compiled and calculated based onthe 0.1C resolution offered by the automatic fiber opticalmethod. Information on the types of samples
47、 and their respec-tive average freezing point is contained in the research report.214. Keywords14.1 automatic freezing point; automatic fiber opticalmethod; aviation gasoline; aviation turbine fuels; freezingpointD7154053ANNEX(Mandatory Information)A1. AUTOMATIC FIBER OPTICAL FREEZING POINT APPARATU
48、SA1.1 Test Chamber, configuration of jacketed test tube andjacketed enclosure as described in A1.1.1 and A1.1.2.A1.1.1 Jacketed Test Tube, borosilicate glass tube, double-walled, unsilvered vessel as shown in Fig. A1.1, similar to aDewar flask, the space between the test tube and the outer glassjack
49、et being filled at atmospheric pressure with dry nitrogen orair.A1.1.2 Jacketed Enclosure, similar to the one shown in Fig.A1.1, with connections for circulation of cooling/heatingmedium around the jacketed test tube. The enclosure shallpermit the necessary depth of immersion of the jacketed testtube into the cooling/heating medium and is attached aroundthe jacketed test tube. The immersion depth is determined asfollowsthe meniscus of the test specimen when placed intothe jacketed test tube shall be 15 to 20 mm below the meniscusof the cooling/h
