ASTM_D_2624_-_21a.pdf

Designation:D262421aAn American National StandardDesignation:274/18Standard Test Methods forElectrical Conductivity of Aviation and Distillate Fuels1,2This 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,health,and environmental practices and deter-mine the applicability of regulatory limitations prior to use.For specific precautionary statements,see 7.1,7.1.1,and11.2.1.1.5 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade(TBT)Committee.2.Referenced Documents2.1 ASTM Standards:3D4306 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 to1These test methods are under the jurisdiction of ASTM International Commit-tee D02 on Petroleum Products,Liquid Fuels,and Lubricants and are the directresponsibility of ASTM Subcommittee D02.J0.04 on Additives and ElectricalProperties.The technically equivalent standard as referenced is under the jurisdic-tion of the Energy Institute Subcommittee SC-B-8.Current edition approved Oct.1,2021.Published November 2021.Originallyapproved in 1967.Last previous edition approved in 2021 as D2624 21.DOI:10.1520/D2624-21A.2These test methods have been developed through the cooperative effort betweenASTM and the Energy Institute,London.ASTM and IP standards were approved byASTM and EI technical committees as being technically equivalent but that does notimply both standards are identical.3For 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 StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recommendations issued by the World Trade Organiz