1、Designation: D2624 15 An 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 o
2、r, 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. S
3、cope*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 rest
4、conductivity).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 distr
5、ibution 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
6、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 specificprecau
7、tionary 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
8、.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 1cu5 1 picomho/m (1)3.1.2 rest conductivity, nthe reciprocal of the resistivity ofuncharged fuel in the
9、 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
10、 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
11、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.
12、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 ex
13、pandedranges 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 o
14、f 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. P
15、ublished 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
16、 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 States15. Significance and Use5.1 The ability of a fuel to dissipate
17、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 high potentials in a
18、receiving tank are avoided.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
19、 is needed.3,46.2 Thermometer, having a suitable range for measuring fueltemperature 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-HHmeas
20、ures and stores the sample 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 follo
21、wed by analytical gradetoluene (Warning Flammable. Vapor harmful).7.1.1 A mixture of 50 % volume analytical grade isopropa-nol and 50 % volume analytical grade heptane (WarningFlammable. Vapor harmful) is a satisfactory substitute fortoluene.8. Sampling8.1 Fuel conductivity measurements should be ma
22、de in situor at the point of 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 obtain
23、ed.If the cell has been in 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 ca
24、n be avoided bystoring the cell at a temperature 2 C to 5 C 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 stron
25、g light sources.Samples in clear 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 samplingcontai
26、ners refer to Practice D4306.8.4 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
27、 Conductivity measurements should 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
28、be thoroughlyrinsed with cleaning 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
29、avoided bystoring the cell at a temperature 2 C to 5 C 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 th
30、e probe during previous tests will 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 i
31、nstrument calibration procedures detailedin AnnexA1 AnnexA5 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, TankT
32、rucks, etc.For field measurements 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 equipped3The foll
33、owing 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 from MBA InstrumentsGmbH, Fried
34、rich-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 Headquarters. Your com-ments will re
35、ceive 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 152with one to lower the cell into the tank. High impedance handheld meters are sus
36、ceptible to electrical transients 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 mete
37、r calibration as detailed in Annex 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 conduc
38、tivity cell in an up-and-downmotion 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
39、Petroleum Institute in RP2003 recommends 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
40、instrument record the highest reading 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
41、 range) is used. Record the fuel 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
42、repeated press thesample button 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)Prior totaking samples, take extreme care to ensure that all conta
43、inersand measuring vessels have 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 f
44、rom previous tests. Transfer 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
45、the measuring vessel. Then transfer 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 th
46、e procedure in 11.2.2 and the 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.NOT
47、E 5When using an analog meter, 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
48、 Model JF-1A reports to the display 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
49、 probe. Since the displayedconductivity 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 recogn
