ASTM_D_5972_-_16.pdf

Designation:D597216Designation:435/15Standard Test Method forFreezing Point of Aviation Fuels(Automatic PhaseTransition Method)1This standard is issued under the fixed designation D5972;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A 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 U.S.Department of Defense.1.Scope*1.1 This test method covers the determination of the tem-perature below which solid hydrocarbon crystals form inaviation turbine fuels.1.2 This test method is designed to cover the temperaturerange of 80 C to 20 C;however,2003 Joint ASTM/IPInterlaboratory Cooperative Test Program mentioned in 12.4has only demonstrated the test method with fuels havingfreezing points in the range of 42 C to 60 C.1.3 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.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 limitations prior to use.For specificwarning statements,see 7.1,7.3,and 7.5.2.Referenced Documents2.1 ASTM Standards:2D2386 Test Method for 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 cooling,disappear when the temperature of the fuel is allowed to riseunder specified conditions of test.3.2 Definitions of Terms Specific to This Standard:3.2.1 automatic phase transition method,nin this testmethod,the procedures of automatically cooling a liquidaviation fuel specimen until solid hydrocarbon crystals appear,followed by controlled warming and recording of the tempera-ture at which the solid hydrocarbon crystals completely redis-solve into the liquid phase.3.2.2 Peltier device,na solid-state thermoelectric deviceconstructed with dissimilar semiconductor materials,config-ured in such a way that it will transfer heat to and away froma test specimen dependent on the direction of electric currentapplied to the device.4.Summary of Test Method4.1 Aspecimen is cooled at a rate of 15 C min 6 5 C minby a Peltier device while continuously being illuminated by alight source.The specimen is continuously monitored by anarray of optical detectors for the first formation of solidhydrocarbon crystals.Once the hydrocarbon crystals areformed,the specimen is then warmed at a rate of 10 C min 60.5 C min until the last hydrocarbon crystals return to theliquid phase.The detectors are sufficient in number to ensurethat any solid hydrocarbon crystals are detected.The specimentemperature at which the last hydrocarbon crystals return to theliquid phase is recorded as the freezing point.5.Significance and Use5.1 The freezing point of an aviation fuel is the lowesttemperature at which the fuel remains free of solid hydrocar-bon crystals.These crystals can restrict the flow of fuel throughthe fuel system of the aircraft.The temperature of the fuel inthe aircraft tank normally decreases during flight depending onaircraft speed,altitude,and flight duration.The freezing pointof the fuel must always be lower than the minimum operationalfuel temperature.5.2 Petroleum blending operations require precise measure-ment of the freezing point.5.3 This test method produces results which have beenfound to be equivalent to Test Method D2386 and expresses1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products,Liquid Fuels,and Lubricants and is the direct responsibility ofSubcommittee D02.07 on Flow Properties.Current edition approved June 1,2016.Published June 2016.Originallyapproved in 1996.Last previous edition approved in 2015 as D5972 15.DOI:10.1520/D5972-16.2For 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.*A Summary of Changes section appears at the end of this standardCopyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 results to the nearest 0.1 C,with improved precision over TestMethod D2386.This test method also eliminates most of theoperator time and judgment required by Test Method D2386.5.4 When specification requires Test Method D2386,do notsubstitute this test method or any other test method.6.Apparatus6.1 Automatic Apparatus3This apparatus consists of amicroprocessor-controlled test chamber that is capable ofcooling and heating the test specimen,optically observing theappearance and disappearance of solid hydrocarbon crystals,