ASTM D6986-03(2010)
(Test Method)Standard Test Method for Free Water, Particulate and Other Contamination in Aviation Fuels (Visual Inspection Procedures)
Standard Test Method for Free Water, Particulate and Other Contamination in Aviation Fuels (Visual Inspection Procedures)
SIGNIFICANCE AND USE
The two procedures in the test method provide rapid methods for field detection of free water and solid contaminants, or any other visually apparent contamination. Uncertain or marginal results by either of these methods would normally result in the performance of methods such as D2276, D5452, or D3240 for quantitative determination of contaminants.
Particulate determination in appearance tests is sensitive to sampling procedures. The presence of a small number of particles may indicate, for example, that the sample line was not flushed to provide a representative sample. The persistent presence of even a small number of particles, however, may be cause for further investigation depending on the situation.
Experience has shown that an experienced tester using a clear bottle can detect as little as 40 ppm of free, suspended water in the fuel. Thus, a fuel rated as clear and bright can still fail lower limits set by quantitative methods. A rater will also have difficulty resolving particles smaller than 40 μm. Smaller particles must be determined by other than visual methods such as D2276, D5452 or chemical field tests listed in Manual 5.
Experience has shown the visual appearance of fuel in a white porcelain bucket to be the most suitable method for the detection of dye contamination or other unusual discoloration. In the U. S., the white porcelain bucket is used to detect the dye.
SCOPE
1.1 This test method covers two procedures for establishing the presence of suspended free water, solid particulate, and other contaminants in aviation gasoline and aviation turbine fuels.
1.1.1 Both procedures are intended primarily for use as field tests with the fuel at handling temperature.
1.1.2 Procedure A uses transparent sample containers; Procedure B uses opaque containers.
1.2 Both procedures are rapid methods for contamination detection and include ratings of haze appearance and particulate presence.
1.3 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.
General Information
Relations
Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: D6986 − 03(Reapproved 2010) An American National Standard
Standard Test Method for
Free Water, Particulate and Other Contamination in Aviation
Fuels (Visual Inspection Procedures)
This standard is issued under the fixed designation D6986; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
INTRODUCTION
Fuel quality is paramount in aviation fuels because of their critical application. Many successive
types of inspections are conducted to ensure quality protection. Rapid, visual inspections carried out
at various locations in the fuel supply system are a critical part of the inspection program. Experience
hasshownthatsubjectiveevaluationssuchasdescribedbythistestmethodformaneffectivefieldalert
system that is backed by other, more quantitative tests.
The present test method duplicates much of Test Method D4176, a test method applicable to all
distillate fuels. However, the present test method also includes field methods applicable especially to
aviation fuels, and is therefore published as a separate test method.
1. Scope D4057 Practice for Manual Sampling of Petroleum and
Petroleum Products
1.1 This test method covers two procedures for establishing
D4176 Test Method for FreeWater and Particulate Contami-
the presence of suspended free water, solid particulate, and
nation in Distillate Fuels (Visual Inspection Procedures)
other contaminants in aviation gasoline and aviation turbine
D5452 Test Method for Particulate Contamination in Avia-
fuels.
tion Fuels by Laboratory Filtration
1.1.1 Both procedures are intended primarily for use as field
tests with the fuel at handling temperature.
2.2 ASTM Adjuncts:
1.1.2 Procedure A uses transparent sample containers; Pro- ADJD417601 Distillate Fuel Bar Chart
cedure B uses opaque containers.
ADJD417602 Distillate Fuel Haze Rating Standard
1.2 Both procedures are rapid methods for contamination
3. Terminology
detection and include ratings of haze appearance and particu-
late presence.
3.1 Definitions of Terms Specific to This Standard:
1.3 The values stated in SI units are to be regarded as the 3.1.1 aviation fuels—as used in this standard, the term
includes both aviation gasoline and aviation turbine fuels.
standard. The values given in parentheses are for information
only.
3.1.2 clear and bright—a condition in which the fuel
contains no visible water drops or particulates and is free of
2. Referenced Documents
haze or cloudiness.
2.1 ASTM Standards:
D2276 Test Method for Particulate Contaminant in Aviation 3.1.3 free water—water in excess to that soluble in the fuel
Fuel by Line Sampling at the temperature of the test and may appear in the fuel as a
haze, cloudiness, droplets, or water layer.
D3240 Test Method for Undissolved Water In Aviation
Turbine Fuels
3.1.4 solid particulates—small solid or semi-solid particles,
sometimes referred to as silt or sediment, present in a fuel as
This test method is under the jurisdiction of ASTM Committee D02 on
the result of contamination by airborne dusts, corrosion by-
Petroleum Products and Lubricants and is the direct responsibility of Subcommittee
products, or wear products.
D02.J0 on Aviation Fuels.
Current edition approved July 1, 2010. Published October 2010. Originally
published in 2003. Last previous editon approved in 2003 as D6986–03. DOI:
10.1520/D6986-03R10.
2 3
For referenced ASTM standards, visit the ASTM website, www.astm.org, or Available from ASTM International Headquarters. Order Adjunct No.
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM ADJD417601.
Standards volume information, refer to the standard’s Document Summary page on Available from ASTM International Headquarters. Order Adjunct No.
the ASTM website. ADJD417602.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D6986 − 03 (2010)
4. Summary of Test Method particlesmustbedeterminedbyotherthanvisualmethodssuch
as D2276, D5452 or chemical field tests listed in Manual 5.
4.1 The test method describes two types of sampling con-
tainers for evaluating the appearance of aviation fuel samples.
5.3 Experience has shown the visual appearance of fuel in a
Procedure A covers transparent sample containers, including white porcelain bucket to be the most suitable method for the
the open jar and the closed circuit sampler, while Procedure B
detection of dye contamination or other unusual discoloration.
uses opaque containers such as the white bucket. In the U. S., the white porcelain bucket is used to detect the
dye.
4.2 Intheopenjarprocedure,aminimumof750mL(24oz)
of fuel is placed into a clear one litre (1 qt) container and
6. Apparatus
examined visually. The jar is then closed and the sample is
swirled and examined for visual sediment and water at the
6.1 Cylindrical Clear Container, such as:
bottom of the vortex.Additionally, fuel clarity may be rated by
6.1.1 Clear Container, with lid, capable of holding 750 mL
placing a standard bar chart behind the sample and comparing
(nominal 1 U.S. qt) of fuel and having a diameter of 100 6 10
its visual appearance with the standard haze rating photo-
mm (4 6 0.4 in.). There should be no gasket in the lid.
graphs. The presence or absence of free water and of particu-
6.1.2 Closed Circuit Sampler, holding about 4 L(1 gal U.S.)
lates is reported.
of fuel and being permanently mounted to receive fuel from a
fuel line or a storage tank and having inlet and outlet valves to
4.3 In the closed circuit sampler procedure, approximately
control filling and emptying of the container. The sampler base
3500 mL (0.9 U.S. gal) of fuel is placed into the sampler and
is normally conical and incorporates the fuel inlet and outlet.
is examined for clarity and for visual sediment or water
The fill port is designed to cause the fuel to swirl around the
droplets on the bottom of the sampler.Additionally, fuel clarity
sides of the clear glass tube. The circuit sampler may also
may be rated by placing a standard bar chart behind the sample
contain hydrometer and chemical water detection ports.
and comparing its visual appearance with the standard haze
rating photographs. The presence or absence of free water and
6.2 Appearance Card and Photographs:
of particulates is reported.
6.2.1 Paper Card (Bar Chart), laminated in clear plastic
4.4 In the white bucket procedure fuel to a depth of having five parallel lines of different widths (see ASTM
approximately 15 cm (6 in.) is collected in a white porcelain adjunct ADJD417601).
coated or stainless steel bucket. The sample is examined for
6.2.2 Appearance Photographs, a series of standard photo-
solids or sediment, or both, on the bottom of the bucket. graphs of the bar chart through a series of samples of different
Sample clarity can be checked by the appearance of a small,
haze levels, numbered from one through six. Photograph No. 1
shiny coin on the bucket’s bottom. If the fuel is dry, the raised is the clearest, while No. 6 represents the densest haze (see
letters on the coin should be easily readable. The amount of
ASTM adjunct ADJD417602). A fuel sample rated clear and
sediment can be described by a letter category using a rating bright will have a rating of “one.”
guide.
6.2.2.1 The differences between these haze levels are arbi-
trary and are not intended to represent equivalent increases in
4.5 In both procedures, the sample is inspected for color or
suspended water content or particulates. It is essential,
other unusual appearance.
therefore, that only the proper approved bar charts and photo-
4.6 Field inspection procedures are performed immediately
graphs be used.
after sampling at fuel handling temperature conditions.
6.3 Opaque Sample Containers:
6.3.1 White Bucket, a circular bucket with straight but
5. Significance and Use
non-parallel sides and a flat bottom and a minimum capacity of
5.1 The two procedures in the test method provide rapid
7.5 L (2.0 U.S. gal) and approximately 20 cm (8 in.) high,
methods for field detection of free water and solid
either coated with white porcelain enamel or made of stainless
contaminants, or any other visually apparent contamination.
steel. Porcelain coatings must be free of dark spots, chips, or
Uncertain or marginal results by either of these methods would
other surface damage, most particularly on the bottom of the
normally result in the performance of methods such as D2276,
bucket. Stainless steel buckets shall be made of a rust-resistant
D5452,or D3240 for quantitative determination of contami-
steel and have a polished internal surface. The white porcelain
nants.
bucket should be used for the optimum detection of unusual
5.1.1 Particulate determination in appearance tests is sensi-
coloration.
tivetosamplingprocedures.Thepresenceofasmallnumberof
particles may indicate, for example, that the sample line was NOTE 1—A quantitative description of acceptable white color is in
preparation.
not flushed to provide a representative sample. The persistent
NOTE 2—Buckets made of white, hard plastic have been found to stain
presence of even a small number of particles, however, may be
a yellow color over time, which can make it difficult to observe a haze or
cause for further investigation depending on the situation.
color changes. The use of plastic containers is also discouraged unless
provision is made for bonding such containers to the filling line.
5.2 Experience has shown that an experienced tester using a
clear bottle can detect as little as 40 ppm of free, suspended
water in the fuel.Thus, a fuel rated as clear and bright can still
fail lower limits set by quantitative methods. A rater will also
Manual 5, Aviation Fuel Quality Control Procedures, 2nd Ed., ASTM
have difficulty resolving particles smaller than 40 µm. Smaller International, W. Conshohocken, PA, 1995.
D6986 − 03 (2010)
TABLE 1 Particulate Appearance Ratings
6.4 Color and Particle Assessment Rating Guide:
6.4.1 This guide contains both a series of photographs of Rating
Rating Description
Guide
particulates of differing concentrations, each having a different
A
Clear A no particles , silt, sediment, dye, rust, or
letter rating, and a series of color photographs for rating filter
solids.
membranes obtained by Test Methods D2276. For this test
Slight B-C several fine to small size particles.
particulates
method, only the particle rating scale is used. The particle
Particulate D many small particles floating or settled on
rating scale does not bear a direct relationship to the mass of
matter bottom
particulates but is simply a way of communicating the amount of container.
Dirty E-1 discoloration or many particles dispersed in
of visible particulates in the sample.
fuel
or settled on bottom of container.
7. Sampling
A
Particulates determination is sensitive to sampling procedures. See 5.1.1.
7.1 Sampling shall be consistent with the procedures in
Practice D4057.
TABLE 2 Water Contaminant Appearance Ratings
7.2 Draw the sample for a field test directly into the test
Rating Description
container using the following procedure:
Bright no suspended or visible free water, sample is bright (slight
7.2.1 Ensure that the sampling valve is free of loose solid
sparkle). Air bubbles may cause hazy appearance immediately
contaminants. If rust or other loose encrustation is present,
after the sample is drawn, but haze clears from the bottom up.
Hazy fine droplets dispersed through sample, may be temporary due
remove with a cloth; then flush the sampling valve prior to
to sample cooling.
taking the actual sample.
Cloudy fine droplets dispersed through sample, giving it milky
7.2.2 Ensure the displacement the fuel volume in the piping
appearance.
Wet droplets or water layer on bottom of container or clinging to
between the sample tap and the storage tank This displacement
sides.
volume should be discarded as it may not be representative of
the fuel to be tested.
7.2.2.1 All fluid obtained from a filter sump should be kept
as the sample.
7.2.3 Rinse a clean test container thoroughly with the fuel area, avoiding light reflections on the front of the container as
being sampled. (Warning—Flammable, keep away from heat, much as possible. Place the bar chart directly behind the
sparks, and open flames.) container, with the lines toward the container and parallel with
7.2.4 Draw the sample continuously, opening the valve the bottom of the container.The narrowest line should be at the
completely to obtain a full flush. Do not open or close taps or bottom of the container. Directly facing the container and bar
valves during sample draw as this action can affect sample chart, compare the appearance of the bar chart through the
quality. sample with the standard photographs. Place the photographs
next to the container so that they are lighted similarly to the
7.3 If the test is to be conducted on fuel taken in a separate
sample. Select the photograph closest in appearance to the
container for laboratory testing, the container should be shaken
sample. Notice that the differences between photographs con-
vigorously before decanting the fuel into the viewing equip-
sist both of the successive disappearance of lines as well as the
ment.Sampletransfershouldberapidenoughtoavoidchanges
gradual lightening of all the lines. Record the number of the
in sample temperature.
thinnest line which is visible through the sample, or record
“six” if no lines are visible.
8. Procedures
8.1.2 Closed Circuit Sampler:
8.1 Procedure A—Clear, Transparent Containers:
8.1.2.1 With fuel flowing under pressure in the main fuel
8.1.1 Open Glass or Plastic Container:
line, open the fill valve wide, filling the glass jar to within
8.1.1.1 Visual Observation—Fill container about three-
about 25 mm (1 in.) from the top.
fourths full. Immediately check for evidence of water or
8.1.2.2 Lettheproductsettlefor1minormore,ifnecessary,
particulate contamination by holding the sample to the light
toremoveairbubbles.(Caution—Thevisualresultsmaydiffer
and visually examining for haze or lack of clarity. Close the
from the photographs if the circuit sampler has a diameter
container and swirl the sample to produce a vortex and
different from that of the 100 mm (4 in.) jar used in the
examine the bottom of the vortex for particulate matter and
photographs.)
water droplets. Also look for brown slime or a water layer on
8.1.2.3 Examine the glass sampler for hazy/cloudy condi-
the bottom of the container. Record the particulate and water
tions and the bottom for w
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