1、Designation: D 6986 03An American National StandardStandard Test Method forFree Water, Particulate and Other Contamination in AviationFuels (Visual Inspection Procedures)1This standard is issued under the fixed designation D 6986; the number immediately following the designation indicates the year o
2、foriginal adoption or, in the case of revision, the 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.INTRODUCTIONFuel quality is paramount in aviation fuels because of th
3、eir critical application. Many successivetypes of inspections are conducted to ensure quality protection. Rapid, visual inspections carried outat various locations in the fuel supply system are a critical part of the inspection program. Experiencehas shown that subjective evaluations such as describ
4、ed by this test method form an effective field alertsystem that is backed by other, more quantitative tests.The present test method duplicates much of Test Method D 4176, a test method applicable to alldistillate fuels. However, the present test method also includes field methods applicable especial
5、ly toaviation fuels, and is therefore published as a separate test method.1. Scope1.1 This test method covers two procedures for establishingthe presence of suspended free water, solid particulate, andother contaminants in aviation gasoline and aviation turbinefuels.1.1.1 Both procedures are intende
6、d primarily for use as fieldtests with the fuel at handling temperature.1.1.2 Procedure A uses transparent sample containers; Pro-cedure B uses opaque containers.1.2 Both procedures are rapid methods for contaminationdetection and include ratings of haze appearance and particu-late presence.1.3 The
7、values stated in SI units are to be regarded as thestandard. The values given in parentheses are for informationonly.2. Referenced Documents2.1 ASTM Standards:2D 2276 Test Methods for Particulate Contaminant in Avia-tion Fuel by Line SamplingD 3240 Test Method for Undissolved Water in AviationTurbin
8、e FuelsD 4057 Practice for Manual Sampling of Petroleum andPetroleum ProductsD 4176 Test Method for Free Water and Particulate Con-tamination in Distillate Fuels (Visual Inspection Proce-dures)2.2 ASTM Adjuncts:ADJD417601 Distillate Fuel Bar Chart3ADJD417602 Distillate Fuel Haze Rating Standard43. T
9、erminology3.1 Definitions of Terms Specific to This Standard:3.1.1 aviation fuelsas used in this standard, the termincludes both aviation gasoline and aviation turbine fuels.3.1.2 clear and brighta condition in which the fuelcontains no visible water drops or particulates and is free ofhaze or cloud
10、iness.3.1.3 free waterwater in excess to that soluble in the fuelat the temperature of the test and may appear in the fuel as ahaze, cloudiness, droplets, or water layer.3.1.4 solid particulatessmall solid or semi-solid particles,sometimes referred to as silt or sediment, present in a fuel asthe res
11、ult of contamination by airborne dusts, corrosion by-products, or wear products.4. Summary of Test Method4.1 The test method describes two types of sampling con-tainers for evaluating the appearance of aviation fuel samples.Procedure A covers transparent sample containers, includingthe open jar and
12、the closed circuit sampler, while Procedure Buses opaque containers such as the white bucket.1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products and Lubricants and is the direct responsibility of SubcommitteeD02.J0 on Aviation Fuels.Current edition approved Dec. 1,
13、 2003. Published January 2004.2For 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.3Available from ASTM Internatio
14、nal Headquarters. Order Adjunct No.ADJD417601.4Available from ASTM International Headquarters. Order Adjunct No.ADJD417602.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.4.2 In the open jar procedure, a minimum of 750 mL (24 oz)of f
15、uel is placed into a clear one litre (1 qt) container andexamined visually. The jar is then closed and the sample isswirled and examined for visual sediment and water at thebottom of the vortex. Additionally, fuel clarity may be rated byplacing a standard bar chart behind the sample and comparingits
16、 visual appearance with the standard haze rating photo-graphs. The presence or absence of free water and of particu-lates is reported.4.3 In the closed circuit sampler procedure, approximately3500 mL (0.9 U.S. gal) of fuel is placed into the sampler andis examined for clarity and for visual sediment
17、 or waterdroplets on the bottom of the sampler. Additionally, fuel claritymay be rated by placing a standard bar chart behind the sampleand comparing its visual appearance with the standard hazerating photographs. The presence or absence of free water andof particulates is reported.4.4 In the white
18、bucket procedure fuel to a depth ofapproximately 15 cm (6 in.) is collected in a white porcelaincoated or stainless steel bucket. The sample is examined forsolids or sediment, or both, on the bottom of the bucket.Sample clarity can be checked by the appearance of a small,shiny coin on the buckets bo
19、ttom. If the fuel is dry, the raisedletters on the coin should be easily readable. The amount ofsediment can be described by a letter category using a ratingguide.4.5 In both procedures, the sample is inspected for color orother unusual appearance.4.6 Field inspection procedures are performed immedi
20、atelyafter sampling at fuel handling temperature conditions.5. Significance and Use5.1 The two procedures in the test method provide rapidmethods for field detection of free water and solid contami-nants, or any other visually apparent contamination. Uncertainor marginal results by either of these m
21、ethods would normallyresult in the performance of methods such as D 2276, D 5452,or D 3240 for quantitative determination of contaminants.5.1.1 Particulate determination in appearance tests is sensi-tive to sampling procedures. The presence of a small number ofparticles may indicate, for example, th
22、at the sample line wasnot flushed to provide a representative sample. The persistentpresence of even a small number of particles, however, may because for further investigation depending on the situation.5.2 Experience has shown that an experienced tester using aclear bottle can detect as little as
23、40 ppm of free, suspendedwater in the fuel. Thus, a fuel rated as clear and bright can stillfail lower limits set by quantitative methods. A rater will alsohave difficulty resolving particles smaller than 40 m. Smallerparticles must be determined by other than visual methods suchas D 2276, D 5452 or
24、 chemical field tests listed in Manual 5.55.3 Experience has shown the visual appearance of fuel in awhite porcelain bucket to be the most suitable method for thedetection of dye contamination or other unusual discoloration.In the U. S., the white porcelain bucket is used to detect thedye.6. Apparat
25、us6.1 Cylindrical Clear Container, such as:6.1.1 Clear Container, with lid, capable of holding 750 mL(nominal 1 U.S. qt) of fuel and having a diameter of 100 6 10mm (4 6 0.4 in.). There should be no gasket in the lid.6.1.2 Closed Circuit Sampler, holding about 4 L (1 gal U.S.)of fuel and being perma
26、nently mounted to receive fuel from afuel line or a storage tank and having inlet and outlet valves tocontrol filling and emptying of the container. The sampler baseis normally conical and incorporates the fuel inlet and outlet.The fill port is designed to cause the fuel to swirl around thesides of
27、the clear glass tube. The circuit sampler may alsocontain hydrometer and chemical water detection ports.6.2 Appearance Card and Photographs:6.2.1 Paper Card (Bar Chart), laminated in clear plastichaving five parallel lines of different widths (see ASTMadjunct ADJD417601).6.2.2 Appearance Photographs
28、, a series of standard photo-graphs of the bar chart through a series of samples of differenthaze levels, numbered from one through six. Photograph No. 1is the clearest, while No. 6 represents the densest haze (seeASTM adjunct ADJD417602). A fuel sample rated clear andbright will have a rating of “o
29、ne.”6.2.2.1 The differences between these haze levels are arbi-trary and are not intended to represent equivalent increases insuspended water content or particulates. It is essential, there-fore, that only the proper approved bar charts and photographsbe used.6.3 Opaque Sample Containers:6.3.1 White
30、 Bucket, a circular bucket with straight butnon-parallel sides and a flat bottom and a minimum capacity of7.5 L (2.0 U.S. gal) and approximately 20 cm (8 in.) high,either coated with white porcelain enamel or made of stainlesssteel. Porcelain coatings must be free of dark spots, chips, orother surfa
31、ce damage, most particularly on the bottom of thebucket. Stainless steel buckets shall be made of a rust-resistantsteel and have a polished internal surface. The white porcelainbucket should be used for the optimum detection of unusualcoloration.NOTE 1A quantitative description of acceptable white c
32、olor is inpreparation.NOTE 2Buckets made of white, hard plastic have been found to staina yellow color over time, which can make it difficult to observe a haze orcolor changes. The use of plastic containers is also discouraged unlessprovision is made for bonding such containers to the filling line.6
33、.4 Color and Particle Assessment Rating Guide:66.4.1 This guide contains both a series of photographs ofparticulates of differing concentrations, each having a differentletter rating, and a series of color photographs for rating filtermembranes obtained by Test Methods D 2276. For this testmethod, o
34、nly the particle rating scale is used. The particle5Manual 5, Aviation Fuel Quality Control Procedures, 2nd Ed., ASTM Interna-tional, W. Conshohocken, PA, 1995.6The “Color and Particle Assessment Rating Guide,” SGTP-3940, is availablefrom Gammon Technical Products, Manasquan, NJ.D6986032rating scale
35、 does not bear a direct relationship to the mass ofparticulates but is simply a way of communicating the amountof visible particulates in the sample.7. Sampling7.1 Sampling shall be consistent with the procedures inPractice D 4057.7.2 Draw the sample for a field test directly into the testcontainer
36、using the following procedure:7.2.1 Ensure that the sampling valve is free of loose solidcontaminants. If rust or other loose encrustation is present,remove with a cloth; then flush the sampling valve prior totaking the actual sample.7.2.2 Ensure the displacement the fuel volume in the pipingbetween
37、 the sample tap and the storage tank This displacementvolume should be discarded as it may not be representative ofthe fuel to be tested.7.2.2.1 All fluid obtained from a filter sump should be keptas the sample.7.2.3 Rinse a clean test container thoroughly with the fuelbeing sampled. (WarningFlammab
38、le, keep away from heat,sparks, and open flames.)7.2.4 Draw the sample continuously, opening the valvecompletely to obtain a full flush. Do not open or close taps orvalves during sample draw as this action can affect samplequality.7.3 If the test is to be conducted on fuel taken in a separatecontain
39、er for laboratory testing, the container should be shakenvigorously before decanting the fuel into the viewing equip-ment. Sample transfer should be rapid enough to avoid changesin sample temperature.8. Procedures8.1 Procedure AClear, Transparent Containers:8.1.1 Open Glass or Plastic Container:8.1.
40、1.1 Visual ObservationFill container about three-fourths full. Immediately check for evidence of water orparticulate contamination by holding the sample to the lightand visually examining for haze or lack of clarity. Close thecontainer and swirl the sample to produce a vortex andexamine the bottom o
41、f the vortex for particulate matter andwater droplets. Also look for brown slime or a water layer onthe bottom of the container. Record the particulate and waterappearance rating of the sample using the ratings in Tables 1and 2. Record the appearance of any other contaminant usingTable 3 as a guide.
42、 Record the ambient temperature.8.1.1.2 Use of Bar Chart and PhotographsImmediatelyon drawing a sample, place the container into a well-lightedarea, avoiding light reflections on the front of the container asmuch as possible. Place the bar chart directly behind thecontainer, with the lines toward th
43、e container and parallel withthe bottom of the container. The narrowest line should be at thebottom of the container. Directly facing the container and barchart, compare the appearance of the bar chart through thesample with the standard photographs. Place the photographsnext to the container so tha
44、t they are lighted similarly to thesample. Select the photograph closest in appearance to thesample. Notice that the differences between photographs con-sist both of the successive disappearance of lines as well as thegradual lightening of all the lines. Record the number of thethinnest line which i
45、s visible through the sample, or record“six” if no lines are visible.8.1.2 Closed Circuit Sampler:8.1.2.1 With fuel flowing under pressure in the main fuelline, open the fill valve wide, filling the glass jar to withinabout 25 mm (1 in.) from the top.8.1.2.2 Let the product settle for 1 min or more,
46、 if necessary,to remove air bubbles. (CautionThe visual results may differfrom the photographs if the circuit sampler has a diameterdifferent from that of the 100 mm (4 in.) jar used in thephotographs.)8.1.2.3 Examine the glass sampler for hazy/cloudy condi-tions and the bottom for water droplets, s
47、olid contaminants,brown slimes, or a combination thereof. Record the particulateand water appearance ratings of the sample using the ratings inTables 1 and 2. Record the appearance of any other contami-nant using Table 3 as a guide. If desired, the bar chart andphotos can be used to rate sample clar
48、ity as described in8.1.1.2. Record the ambient temperature.NOTE 3While small water droplets and air bubbles may appearsimilar, air bubbles will rise while water droplets will settle upon standing.8.1.2.4 If the sampler is fitted with an optional self-sealingvalve assembly for a free water field test
49、ing kit, a fuel samplemay be drawn at this time.8.1.2.5 Open the drain valve to drain the sampler.8.2 Procedure BOpaque Containers:8.2.1 White BucketIn the U.S., only the white porcelainbucket is recommended for the optimum detection of red dyecontamination.8.2.1.1 Bond the bucket electrically to the fuel system or tothe ground by using a bonding wire.NOTE 4When using a white porcelain bucket, the porcelain coatingshould not be thought of as an insulating layer for electrical bonding.8.2.1.2 If necessary, wipe external contamination from thefill valve. Flush the samplin
