1、Designation: D 3240 05An American National StandardStandard Test Method forUndissolved Water In Aviation Turbine Fuels1This standard is issued under the fixed designation D 3240; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the
2、year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) 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*1.1 This test method covers the
3、 measurement of undissolvedwater in aviation turbine fuels in flowing fuel streams withoutexposing the fuel sample to the atmosphere or to a samplecontainer. The usual range of test readings covers from 1 to 60ppm of free water. This test method does not detect waterdissolved in the fuel, and thus t
4、est results for comparable fuelstreams can vary with fuel temperature and the degree of watersolubility in the fuel.1.2 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
5、 safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Terminology2.1 Definitions of Terms Specific to This Standard:2.1.1 free waterwater not dissolved in the fuel.3. Summary of Test Method3.1 A measured sample of fuel is passed through as uraninedye
6、-treated filter pad. Undissolved (free) water in the fuel willreact with the uranine dye. When the pad is subsequentlyilluminated by ultraviolet (UV) light, the dye previouslycontacted by free water will fluoresce a bright yellow with thebrightness increasing for increasing amounts of free water int
7、he fuel. The UV light-illuminated pad is compared to a knownstandard using a photocell comparator, and the free water in thefuel sample is read out in parts per million by volume. Byvarying the fuel sample size, the range of the test method canbe increased.4. Significance and Use4.1 Undissolved (fre
8、e) water in aviation fuel can encouragethe growth of microorganisms and subsequent corrosion in thetanks of aircraft and can also lead to icing of filters in the fuelsystem. Control of free water is exercised in ground fuelingequipment by use of filter-coalescers and water separators.5. Apparatus5.1
9、 Test Pad RaterA device2,3for comparing the fluores-cence of the test pad to a known standard, while both areilluminated by the same source of UV light, shall be used. Theamount of UV light striking the standard shall be modulateduntil the total fluorescence of the test pad and the standard areequal
10、; this shall be determined using a photocell bridge circuitnull indicator. The light modulating device for controlling theUV light striking the standard shall provide a direct reading inparts per million by volume of free water.5.2 Test PadsAbsorbent filter disks of 25-mm diametershall be coated on
11、one side with uranine (sodium fluorescein)dye at a concentration of 0.23 to 0.29 mg per 25 mm pad. Thetest pads3,4shall be individually packaged in hermeticallysealed envelopes or other suitable containers. Fresh, unusedtest pads shall have an orange color over the dyed surface. Anydiscoloration, un
12、evenness in dye content, or faded (to a yellowcolor) appearance shall be cause for rejection.5.3 Test Pad Holder3,5and Sampling LineA test padholder and sampling line shall be used to draw the fuel samplethrough the test pad at a rate of 600 to 800 mL/min. Meansshall be provided to flush the test pa
13、d sampling line and holderimmediately prior to use. The test pad holder shall include anorifice of 1-mm (0.040-in.) diameter upstream of the pad todisperse water droplets in the fuel.1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products and Lubricants and is the dire
14、ct responsibility of SubcommitteeD02.J0 on Aviation Fuels.Current edition approved Nov. 1, 2005. Published November 2005. Originallyapproved in 1973. Last previous edition approved in 2001 as D 324091(2001).2The Aqua-Glo Series II instrument manufactured by Gammon TechnicalProducts, Inc., P.O. Box 4
15、00, Manasquan, NJ 08736-0400 was used in the precisiontest program. The unit is currently available in a Series V configuration, which ischanged only in the power supply. All water content measuring components remainof the same configuration as the Series II instrument. Manufacturers who wish tooffe
16、r similar products are referred to Committee D02 Equipment ReplacementGuidelines.3The sole source of supply of the apparatus known to the committee at this timeis Gammon Technical Products Inc., P.O. Box 400, Manasquan, NJ 08736-0400. Ifyou are aware of alternative suppliers, please provide this inf
17、ormation to ASTMInternational Headquarters. Your comments will receive careful consideration at ameeting of the responsible technical committee,1which you may attend.4Aqua-Glo test pads were used in the Precision Test Program.5A test pad holder was used in the Precision Test Program.1*A Summary of C
18、hanges section appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.5.4 TweezersSuitable clean, dry tweezers shall be used atall times when handling the test pad.5.5 Blotting PaperClean, dry, absorbent p
19、aper towels,blotters, etc., shall be provided for blotting the test pad prior torating to remove excess fuel. The blotter paper shall neitherimpart color or stain nor leave any residue on the test pads.5.6 Sampling Valve Connection, designed to meet the fol-lowing requirements: (1) It shall be mount
20、ed in the samplingpoint and must incorporate a self-sealing quick action couplingdesigned to mate with a suitable connection leading to theselector valve of the sampling assembly. (2) It must becompletely resistant to fuel and be leak proof up to themaximum working pressures to be encountered. (3) I
21、t musthave a minimum of internal recesses which could cause theholdup of contaminant. (4) It must be provided with a dust cap.5.7 Calibrating Standard, calibration of the instrumentshould be performed using a calibrating standard of knownvalues.6. Sampling6.1 The following procedure is applicable fo
22、r dynamic linesamples only; that is, taking the fuel sample directly from thetest system and through the test pad without exposing thesample to the atmosphere or to a sample container. The use ofsample containers such as bottles or cans for the temporarystorage of the sample will result in large err
23、ors and is notrecommended.NOTE 1The amount of free water in a sample is very sensitive to thetemperature of the sample. The use of sample containers such as bottles orcans can result in large errors due to changes in sample temperature,adsorption of water on container walls, etc.6.2 Attach the test
24、pad holder assembly to the sampling porton the system.6.3 Flush the test pad holder assembly immediately prior tosampling, displacing the sampling line with at least twovolumes of test fuel.6.4 Remove the sampling assembly, open the pad holder,and insert the new test pad using tweezers making sure t
25、hat thetreated side of the test pad is facing upstream. Installation of athree-way valve immediately upstream of the test pad holderwill permit flushing with the test pad in place.NOTE 2Do not remove the test pad from the hermetically sealedpackage until ready for use. Do not allow any discrete wate
26、r droplets tocome into contact with the pad (from rain, sneezing, coughing, etc.).Exposure of the test pad to the atmosphere, especially on humid days, willalso ruin the pad in a matter of minutes.6.5 Pass 500 mL of fuel through the pad, accurately mea-suring the test sample quantity. Normal sample
27、volume is 500mL of test fuel, but if the reading is off scale (on high side),sample volumes down to 100 mL in volume may be used. Inthe latter case, a small graduated cylinder should be used tomeasure the sample volume.7. Calibration7.1 The calibrating standard3,6corresponding to a givenundissolved
28、water content is placed in the test pad window.Turn on the lamp and press the photocell comparator button.Zero the photocell comparator by adjusting the light modulat-ing lever until there is a steady reading for 10 to 15 s. This maytake a minute or longer. Always move the light modulatinglever in t
29、he same direction when zeroing the photocell com-parator in calibration or testing to eliminate errors caused byplay in the lever. If the reading obtained does not agree with thecalibration pad rating, adjust the photocell comparator byremoving the plug screw on the side of the photocell compara-tor
30、 at the 45 bend. Insert a small screwdriver, and adjust asnecessary. Repeat the above procedure until the rating obtainedagrees with the calibration pad rating. The instrument shouldbe calibrated prior to use each day, after each hour of use, andwhen the ultraviolet light battery is replaced or rech
31、arged.8. Rating Procedure8.1 Remove the test pad from the sampling holder usingtweezers and press between dry paper blotters or absorbenttowels to remove excess fuel. To blot, press firmly (about 5 lbforce) 3 or 4 times with heel of hand, moving the pad withtweezers each time.8.1.1 For maximum accur
32、acy the test pad should be readwithin 3 min after sampling is initiated. If the test pad is notread immediately after sampling, it must be placed in adesiccator to prevent moisture pickup from the air. However,ratings made on dried test pads, that is, not damp with fuel,should be avoided if possible
33、 since they will give high anderroneous results. Conversely, rating a pad which has not beenwell blotted will give a low reading as the excess fuel willabsorb part of the UV light and decrease fluorescence.8.2 Using tweezers, put the pad into the pad rating device.Turn on the lamp and press the phot
34、ocell button. Continuouslyzero the photocell comparator by adjusting the light modulat-ing lever until there is a steady reading for 10 to 15 s. Alwaysmove the light modulating lever in the same direction whenzeroing the photocell comparator to eliminate errors caused bybacklash. This may take a min
35、ute or longer. Turn off theinstrument light immediately after use to conserve batterypower.8.2.1 The ultraviolet light must be on to get a reading. Thiscan be checked by moving the light modulating lever from oneextreme to another. The photocell comparator meter needleshould swing violently when thi
36、s is done.8.3 Record the instrument reading (estimated to the nearesttenth) and the sample volume. Record the temperature of thefuel.8.4 Visual observation of the used test pad is often of value.This is easily accomplished by removing the photocell com-parator assembly and viewing the test pad. Free
37、 water in fuel isnormally well dispersed and will form an even distribution ofmany, small points of yellow fluorescence on the test pad whenilluminated by ultraviolet light. Large water drops, however,6Replacement calibrating standards, but only if the fluorescing standard for theinstrument is retur
38、ned for comparison rating.D3240052will form a few, large spots of yellow fluorescence on the pad.These large spots may give erroneous readings; the resultshould be disregarded and a new sample tested.9. Calculation9.1 The instrument reads directly if the sample volume is500 mL. Correct the readings
39、for other sample volume bymultiplying reading by 500/sample size in millilitres:Free water, ppm 5meter reading, ppm!500!/sample volume, mL!10. Report10.1 Report the result to the nearest whole number as ppmby volume of undissolved water in fuel, and also the samplevolume used in the test. Report the
40、 temperature of the sampleif available.11. Precision and Bias711.1 The precision (Note 3, Note 4) of this test method asdetermined by statistical examination of test results obtainedby operator-instrument pairs at a common test site is as givenin this section. Each operator used a separate instrumen
41、t.11.1.1 RepeatabilityThe difference between successiveresults obtained by the same operator with the same apparatusunder constant operating conditions on identical test materialwould, in the long run, in the normal and correct operation ofthe test method exceed the following values only in one case
42、 intwenty.Repeatability 5 0.32xwhere x = average of two results in parts per million volumeover the range from 1 through 60 ppm V (Note 5).11.1.2 ReproducibilityThe difference between two singleand independent results obtained by different operators work-ing at a common test site on identical test m
43、aterial would, inthe long run, exceed the following values only in one case intwenty.Reproducibility 5 0.47xNOTE 3The reproducibility values above were estimates from resultsobtained at the same location and on the same day by seven operator/instruments testing identical samples. In the case of this
44、 test method it isnot possible to obtain meaningful results when fuels are shipped todifferent locations since water would separate during shipment.NOTE 4The presence of fuel additives such as corrosion inhibitors,fuel system icing inhibitors, and antistatic materials may affect thecalibration of th
45、e test.NOTE 5Sample size was not found to be a significant factor inprecision. Data were analyzed using a log transformation but the repeat-ability results are expressed in untransformed units.11.1.3 BiasSince there is no accepted reference materialsuitable for determining the bias for the procedure
46、 in TestMethod D 3240 for measuring the undissolved water in avia-tion turbine fuels, bias has not be determined.12. Keywords12.1 calibrating standard; fluorescence; fluorescing stan-dard; free water; sodium fluorescein; undissolved water;uranineSUMMARY OF CHANGESSubcommittee D02.J0 has identified t
47、he location of selected changes to this standard since the last issue(D 324091(2001) that may impact the use of this standard.(1) Revised Footnote 2.ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users
48、 of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every f
49、ive years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box
