1、Designation: D2624 09Designation: 274/99An American National StandardStandard 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
2、, 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 Department of Defense.1. Scope*1
3、.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 restconduc
4、tivity).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 distributio
5、n 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 s
6、tandard 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 specificprecautionar
7、y 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 pic
8、osiemens 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 3 10212V21m215 1cu5 1 picomho/m (1)3.1.2 rest conductivity, nthe reciprocal of the resistivity ofuncharged fuel in the abs
9、ence 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 Met
10、hods4.1 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 e
11、liminatedin 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
12、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 Model 1152 Meter and D-2 Inc. ModelJF-1A-HH are available with expanded ranges but the
13、preci-sion of the extended range meters has not been determined. Ifit is necessary to measure conductivities below 1 pS/m, for1These test methods are under the jurisdiction of ASTM Committee D02 onPetroleum Products and Lubricants and are the direct responsibility of Subcommit-tee D02.J0.04 on Addit
14、ives and Electrical Properties.In the IP, these test methods are under the jurisdiction of the StandardizationCommittee.Current edition approved Dec. 1, 2009. Published February 2010. Originallyapproved in 1967. Last previous edition approved in 2007 as D262407a. DOI:10.1520/D2624-09.2For referenced
15、 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.1*A Summary of Changes section appears at the end of this standard.Copyright
16、 ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.example in the case of clay treated fuels or refined hydrocarbonsolvents, Test Method D4308 should be used.5. Significance and Use5.1 The ability of a fuel to dissipate charge that has beengenera
17、ted 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 high potentials in a receiving tank are avoided
18、.PORTABLE METER METHOD6. Apparatus6.1 Conductivity Cell and Current-Measuring ApparatusBecause hydrocarbon conductivities are extremely low com-pared to aqueous solutions, special equipment that is capable ofgiving an almost instantaneous response with application ofvoltage is needed.3,46.2 Thermome
19、ter, having a suitable range for measuringfuel temperature in the field. A thermometer holder should beavailable so that the temperature can be directly determined forfuel in bulk storage, rail tank cars, and trucks.NOTE 1The Emcee Model 1153 and D-2 Inc. Model JF-1A-HHmeasures and stores the sample
20、 temperature during the test cycle.6.3 Measuring VesselAny suitable vessel capable of hold-ing sufficient fuel to cover the electrodes of the conductivitycell.37. Reagents and Materials7.1 Cleaning SolventsUse isopropyl alcohol (WarningFlammable) if water is suspected followed by analytical gradetol
21、uene (WarningFlammable. Vapor harmful).7.1.1 A mixture of 50 % volume analytical grade isopro-panol and 50 % volume analytical grade heptane (WarningFlammable. Vapor harmful) is a satisfactory substitute fortoluene.8. Sampling8.1 Fuel conductivity measurements should be made in situor at the point o
22、f sampling to avoid changes during sampleshipment. If it is necessary to take samples for subsequentanalysis, the following precautions should be taken:8.1.1 If the cell is in contact with water and the instrumentis switched on, an immediate offscale reading will be obtained.If the cell has been in
23、contact with water, it shall be thoroughlyrinsed with cleaning solvent, preferably isopropyl alcohol, anddried with a stream of air. In hot, humid conditions, conden-sation on the cell can occur, which can cause abnormally highzero, calibration and sample readings. This can be avoided bystoring the
24、cell at a temperature 2 to 5C in excess of themaximum ambient temperature where this is practicable.8.2 The sample size should be as large as practicable (see6.3).8.3 The conductivity of fuels containing static dissipatoradditives is affected by sunlight and other strong light sources.Samples in cle
25、ar glass containers can experience significantconductivity loss within 5 min of sunlight exposure. SeePractice D4306 for further discussion.NOTE 2Test method results are known to be sensitive to tracecontamination from sampling containers. For recommended samplingcontainers refer to Practice D4306.8
26、.4 Prior to taking the samples, all sample containers,including caps, shall be rinsed at least three times with the fuelunder test. Used containers should be thoroughly cleaned withcleaning solvent, if necessary, in accordance with D4306,paragraph 6.6, and air dried.8.5 Conductivity measurements sho
27、uld be made as soon aspossible after sampling and preferably within 24 h.9. Cleaning Procedures9.1 If the cell is in contact with water and the instrument isswitched on, an immediate offscale reading will be obtained. Ifthe cell has been in contact with water, it shall be thoroughlyrinsed with clean
28、ing solvent, preferably isopropyl alcohol, anddried with a stream of air. The meter may display a non-zeroreading caused by condensation forming on the cell when themeter is taken from a cool, dry environment and subjected tohot, humid conditions. This condition can be avoided bystoring the cell at
29、a temperature 2 to 5C in excess of theambient temperature, when practicable.9.2 In normal use, the probe on handheld instrumentsshould be cleaned with toluene or a mixture of heptane andisopropanol and air-dried after use, to ensure that ionicmaterials absorbed on the probe during previous tests wil
30、l notcontaminate the sample and give an erroneous result.10. Calibration10.1 The calibration procedure will be dependent upon theequipment used. The procedures for the instruments listed inFootnote 3 are described in Annex A1-Annex A7.11. Procedure11.1 The specific instrument calibration procedures
31、detailedin Annex A1-Annex A5 are an essential part of the followinggeneralized procedures. The appropriate calibration steps forthe instrument used should be followed prior to commencingthe subsequent procedures.11.2 In Situ Field Measurement on Tanks, Tank Cars, TankTrucks, etc.For field measuremen
32、ts the conductivity metersreferred to in Footnote 3 are considered suitable. The use ofthese meters in hazardous locations may be restricted by theregulatory agency having jurisdiction. The EMCEE 1152 andMalik MLA 900 have an extension cable or can be equippedwith one to lower the cell into the tank
33、. High impedance hand3The following equipment, as listed in RR:D02-1161, RR:D02-1476, RR:D02-1575, and RR:D02-1680 was used to develop the precision statements. Models1150, 1151, 1152, and 1153 from Emcee Electronics, Inc., 520 CypressAve., VeniceFL 34285; Maihak Conductivity Indicator and MLA 900 f
34、rom MBA InstrumentsGmbH, Friedrich-List-Str 5, D-25451 Quickborn, Model JF-1A-HH from D-2Incorporated, 19 Commerce Park Road, Pocasset, MA 02559. This is not anendorsement or certification by ASTM. If you are aware of alternative suppliers,please provide this information to ASTM International Headqu
35、arters. Your com-ments will receive careful consideration at a meeting of the responsible technicalcommittee,1which you may attend.4The older style Maihak Conductivity Indicator (Annex A1) and the EmceeModel 1151 are no longer in production.D2624 092held meters are susceptible to electrical transien
36、ts caused byextension cable flexing during measurements. Failure to holdthe apparatus steady during measurement can result in signifi-cantly poorer precision than shown in Table 1. The followinginstructions apply to the meters referenced in Footnote 3.11.2.1 Check meter calibration as detailed in An
37、nex A1,Annex A2, Annex A4, Annex A5,orAnnex A7, depending onthe meter used. Bond the meter to the tank and lower theconductivity cell into the tank to the desired level taking careto avoid partial immersion or contact with tank water bottoms,if present. Move the conductivity cell in an up-and-downmo
38、tion to remove previous fuel residues. (WarningToprevent static discharge between a charged fuel and a conduc-tive probe inserted into a tank, the appropriate safety precau-tions of bonding and waiting for charge dissipation should beobserved. For example, theAmerican Petroleum Institute in RP2003 r
39、ecommends that a 30-min interval be allowed afterpumping into a storage tank before an operator mounts a tankto insert a sampling device. This will also ensure that the fuelis electrically at rest.)11.2.2 After flushing the cell, hold it steady and afteractivating the instrument record the highest r
40、eading after initialstabilization.This should occur within 3 s. On instruments withmore than one scale range, select the scale that gives thegreatest sensitivity for the conductivity value being deter-mined. Ensure that the appropriate scale multiplying factor (orscale range) is used. Record the fue
41、l temperature.NOTE 3The Emcee Model 1153 automatically measures and recordsthe reading at 3 s. The D-2 Model JF-1A-HH Samples 10 times uponactivation, allow the center bar indicator on the display to come to centerwhich indicates the current reading has repeated, once repeated press thesample button
42、 again to display the conductivity, temperature data andstore the data to the instruments memory.11.3 Laboratory and Field Measurements on Sampled Fu-els:11.3.1 Preparation of Containers (Metal or Glass)Priorto taking samples, take extreme care to ensure that all contain-ers and measuring vessels ha
43、ve been thoroughly cleaned. It ispreferable that containers are laboratory cleaned prior toshipment to the field for sampling (see Section 8).11.3.2 MeasurementRinse the conductivity cell thor-oughly with the fuel under test to remove fuel residuesremaining on the cell from previous tests. Transfer
44、the fuel tothe measuring vessel and record the conductivity of the fuelusing the procedure applicable to the particular apparatus. Ifone of the conductivity meters referenced in Footnote 3 is used,follow these instructions: Rinse the cell concurrently with therinsing of the measuring vessel. Then tr
45、ansfer the sample to betested to the clean, rinsed measuring vessel. Check metercalibration as detailed in Annex A1, Annex A2, Annex A5,orAnnex A7, depending on the meter used. Fully immerse theconductivity cell into the test fuel and measure the conductivityfollowing the procedure in 11.2.2 and the
46、 appropriate Annex.Record the fuel temperature.NOTE 4In order to avoid erroneous readings, it is important to ensurethat the bottom of the conductivity cell does not touch the samplecontainer. This is applicable to all containers, whatever the material ofconstruction.NOTE 5When using an analog meter
47、, measurements exceeding therange of the meter are obvious. With the Emcee Model 1152 Digital Meterand the Maihak MLA 900 Meter, measurements exceeding the range ofthe meter are indicated by a single digit “1” in the left side of the displaywhere 1000s are shown. The D-2 Model JF-1A reports to the d
48、isplay thetext, “Reading Out of Range.” A qualitative conductivity estimate (forwhich precision has not been established) can be made by inserting theprobe in the sample to the first set of holes closest to the tip, which are atthe mid point of the sensing portion of the probe. Since the displayedco
49、nductivity is inversely proportional to the depth of immersion, the valuedisplayed, if any, should be doubled. Conductivities less than 1 pS/m upto 20 000 pS/m can be determined using Test Method D4308. When usingthe Emcee Model 1153 Digital Meter, measurements exceeding the rangeof the meter “OVER” will be displayed.12. Report12.1 Report the electrical conductivity of the fuel and thefuel temperature at which measurement was made. If theelectrical conductivity reads zero on the meter, report less than1 pS/m.NOTE 6It is recognized that the electrical conductivity
