ASTM_D_2624_-_15.pdf

Designation:D262415An American National StandardDesignation:274/99Standard Test Methods forElectrical Conductivity of Aviation and Distillate Fuels1This standard is issued under the fixed designation D2624;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 These test methods cover the determination of theelectrical conductivity of aviation and distillate fuels with andwithout a static dissipator additive.The test methods normallygive a measurement of the conductivity when the fuel isuncharged,that is,electrically at rest(known as the restconductivity).1.2 Two test methods are available for field tests of fuelconductivity.These are:(1)portable meters for the directmeasurement in tanks or the field or laboratory measurement offuel samples,and(2)in-line meters for the continuous mea-surement of fuel conductivities in a fuel distribution system.Inusing portable meters,care must be taken in allowing therelaxation of residual electrical charges before measurementand in preventing fuel contamination.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 specificprecautionary statements,see 7.1,7.1.1,and 11.2.1.2.Referenced Documents2.1 ASTM Standards:2D4306 Practice for Aviation Fuel Sample Containers forTests Affected by Trace ContaminationD4308 Test Method for Electrical Conductivity of LiquidHydrocarbons by Precision Meter3.Terminology3.1 Definitions:3.1.1 picosiemens per metre,nthe unit of electrical con-ductivity is also called a conductivity unit(CU).A siemen isthe SI definition of reciprocal ohm sometimes called mho.1 pS/m 5 1 31021221m215 1 cu5 1 picomho/m(1)3.1.2 rest conductivity,nthe reciprocal of the resistivity ofuncharged fuel in the absence of ionic depletion or polariza-tion.3.1.2.1 DiscussionIt is the electrical conductivity at theinitial instant of current measurement after a dc voltage isimpressed between electrodes,or a measure of the averagecurrent when an alternating current(ac)voltage is impressed.4.Summary of Test Methods4.1 Avoltage is applied across two electrodes in the fuel andthe resulting current expressed as a conductivity value.Withportable meters,the current measurement is made almostinstantaneously upon application of the voltage to avoid errorsdue to ion depletion.Ion depletion or polarization is eliminatedin dynamic monitoring systems by continuous replacement ofthe sample in the measuring cell,or by the use of an alternatingvoltage.The procedure,with the correct selection of electrodesize and current measurement apparatus,can be used tomeasure conductivities from 1 pS/m or greater.The commer-cially available equipment referred to in these methods coversa conductivity range up to 2000 pS/m with good precision(seeSection 12),although some meters can only read to 500 or1000 pS/m.4.1.1 The EMCEE Models 1150,1152,and 1153 Metersand D-2 Inc.Model JF-1A-HH are available with expandedranges but the precision of the extended range meters has notbeen determined.If it is necessary to measure conductivitiesbelow 1 pS/m,for example in the case of clay treated fuels orrefined hydrocarbon solvents,Test Method D4308 should beused.1These test methods are under the jurisdiction of ASTM Committee D02 onPetroleum Products,Liquid Fuels,and Lubricants and are the direct responsibilityof Subcommittee D02.J0.04 on Additives and Electrical Properties.In the IP,these test methods are under the jurisdiction of the StandardizationCommittee.Current edition approved April 1,2015.Published May 2015.Originallyapproved in 1967.Last previous edition approved in 2009 as D2624 09.DOI:10.1520/D2624-15.2For 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 5.Significance and Use5.1 The ability of a fuel to dissipate charge that has beengenerated during pumping and filtering operations is controlledby its electrical conductivity,which depends upon its contentof ion species.If the conductivity is sufficiently high,chargesdissipate fast enough to prevent their accumulation and dan-gerously h