ASTM D6986-03
(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 D 2276, D 5452, or D 3240 for quantitative determination of contaminants.
5.1.1 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 D 2276, D 5452 or chemical field tests listed in Manual 5.5
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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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An American National Standard
Designation:D6986–03
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 D4176 Test Method for Free Water and Particulate Con-
tamination in Distillate Fuels (Visual Inspection Proce-
1.1 This test method covers two procedures for establishing
dures)
the presence of suspended free water, solid particulate, and
2.2 ASTM Adjuncts:
other contaminants in aviation gasoline and aviation turbine
ADJD417601 Distillate Fuel Bar Chart
fuels.
ADJD417602 Distillate Fuel Haze Rating Standard
1.1.1 Both procedures are intended primarily for use as field
tests with the fuel at handling temperature.
3. Terminology
1.1.2 Procedure A uses transparent sample containers; Pro-
3.1 Definitions of Terms Specific to This Standard:
cedure B uses opaque containers.
3.1.1 aviation fuels—as used in this standard, the term
1.2 Both procedures are rapid methods for contamination
includes both aviation gasoline and aviation turbine fuels.
detection and include ratings of haze appearance and particu-
3.1.2 clear and bright—a condition in which the fuel
late presence.
contains no visible water drops or particulates and is free of
1.3 The values stated in SI units are to be regarded as the
haze or cloudiness.
standard. The values given in parentheses are for information
3.1.3 free water—water in excess to that soluble in the fuel
only.
at the temperature of the test and may appear in the fuel as a
2. Referenced Documents haze, cloudiness, droplets, or water layer.
3.1.4 solid particulates—small solid or semi-solid particles,
2.1 ASTM Standards:
sometimes referred to as silt or sediment, present in a fuel as
D2276 Test Method for Particulate Contaminant inAviation
the result of contamination by airborne dusts, corrosion by-
Fuel by Line Sampling
products, or wear products.
D3240 Test Method for Undissolved Water In Aviation
Turbine Fuels
4. Summary of Test Method
D4057 Practice for Manual Sampling of Petroleum and
4.1 The test method describes two types of sampling con-
Petroleum Products
tainers for evaluating the appearance of aviation fuel samples.
Procedure A covers transparent sample containers, including
This test method is under the jurisdiction of ASTM Committee D02 on
the open jar and the closed circuit sampler, while Procedure B
Petroleum Products and Lubricants and is the direct responsibility of Subcommittee
uses opaque containers such as the white bucket.
D02.J0 on Aviation Fuels.
Current edition approved Dec. 1, 2003. Published January 2004. DOI: 10.1520/
D6986-03.
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
4.2 Intheopenjarprocedure,aminimumof750mL(24oz) 6. Apparatus
of fuel is placed into a clear one litre (1 qt) container and
6.1 Cylindrical Clear Container, such as:
examined visually. The jar is then closed and the sample is
6.1.1 Clear Container, with lid, capable of holding 750 mL
swirled and examined for visual sediment and water at the
(nominal 1 U.S. qt) of fuel and having a diameter of 100 6 10
bottom of the vortex.Additionally, fuel clarity may be rated by
mm (4 6 0.4 in.). There should be no gasket in the lid.
placing a standard bar chart behind the sample and comparing
6.1.2 Closed Circuit Sampler,holdingabout4L(1galU.S.)
its visual appearance with the standard haze rating photo-
of fuel and being permanently mounted to receive fuel from a
graphs. The presence or absence of free water and of particu-
fuel line or a storage tank and having inlet and outlet valves to
lates is reported.
control filling and emptying of the container. The sampler base
4.3 In the closed circuit sampler procedure, approximately
is normally conical and incorporates the fuel inlet and outlet.
3500 mL (0.9 U.S. gal) of fuel is placed into the sampler and
The fill port is designed to cause the fuel to swirl around the
is examined for clarity and for visual sediment or water
sides of the clear glass tube. The circuit sampler may also
droplets on the bottom of the sampler.Additionally, fuel clarity
contain hydrometer and chemical water detection ports.
may be rated by placing a standard bar chart behind the sample
6.2 Appearance Card and Photographs:
and comparing its visual appearance with the standard haze
6.2.1 Paper Card (Bar Chart), laminated in clear plastic
rating photographs. The presence or absence of free water and
having five parallel lines of different widths (see ASTM
of particulates is reported.
adjunct ADJD417601).
4.4 In the white bucket procedure fuel to a depth of
6.2.2 Appearance Photographs, a series of standard photo-
approximately 15 cm (6 in.) is collected in a white porcelain
graphs of the bar chart through a series of samples of different
coated or stainless steel bucket. The sample is examined for
haze levels, numbered from one through six. Photograph No. 1
solids or sediment, or both, on the bottom of the bucket.
is the clearest, while No. 6 represents the densest haze (see
Sample clarity can be checked by the appearance of a small,
ASTM adjunct ADJD417602). A fuel sample rated clear and
shiny coin on the bucket’s bottom. If the fuel is dry, the raised
bright will have a rating of “one.”
letters on the coin should be easily readable. The amount of
6.2.2.1 The differences between these haze levels are arbi-
sediment can be described by a letter category using a rating
trary and are not intended to represent equivalent increases in
guide.
suspended water content or particulates. It is essential, there-
4.5 In both procedures, the sample is inspected for color or
fore, that only the proper approved bar charts and photographs
other unusual appearance.
be used.
4.6 Field inspection procedures are performed immediately
6.3 Opaque Sample Containers:
after sampling at fuel handling temperature conditions.
6.3.1 White Bucket, a circular bucket with straight but
non-parallel sides and a flat bottom and a minimum capacity of
5. Significance and Use
7.5 L (2.0 U.S. gal) and approximately 20 cm (8 in.) high,
5.1 The two procedures in the test method provide rapid
either coated with white porcelain enamel or made of stainless
methods for field detection of free water and solid contami-
steel. Porcelain coatings must be free of dark spots, chips, or
nants, or any other visually apparent contamination. Uncertain
other surface damage, most particularly on the bottom of the
or marginal results by either of these methods would normally
bucket. Stainless steel buckets shall be made of a rust-resistant
resultintheperformanceofmethodssuchasD2276,D5452,or
steel and have a polished internal surface. The white porcelain
D3240 for quantitative determination of contaminants.
bucket should be used for the optimum detection of unusual
5.1.1 Particulate determination in appearance tests is sensi-
coloration.
tivetosamplingprocedures.Thepresenceofasmallnumberof
NOTE 1—A quantitative description of acceptable white color is in
particles may indicate, for example, that the sample line was
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
5.2 Experience has shown that an experienced tester using a
provision is made for bonding such containers to the filling line.
clear bottle can detect as little as 40 ppm of free, suspended
6.4 Color and Particle Assessment Rating Guide:
water in the fuel.Thus, a fuel rated as clear and bright can still
6.4.1 This guide contains both a series of photographs of
fail lower limits set by quantitative methods. A rater will also
particulates of differing concentrations, each having a different
have difficulty resolving particles smaller than 40 µm. Smaller
letter rating, and a series of color photographs for rating filter
particlesmustbedeterminedbyotherthanvisualmethodssuch
5 membranes obtained by Test Methods D2276. For this test
as D2276, D5452 or chemical field tests listed in Manual 5.
method, only the particle rating scale is used. The particle
5.3 Experience has shown the visual appearance of fuel in a
rating scale does not bear a direct relationship to the mass of
white porcelain bucket to be the most suitable method for the
particulates but is simply a way of communicating the amount
detection of dye contamination or other unusual discoloration.
of visible particulates in the sample.
In the U. S., the white porcelain bucket is used to detect the
dye.
5 6
Manual 5, Aviation Fuel Quality Control Procedures, 2nd Ed.,ASTM Interna- The “Color and Particle Assessment Rating Guide,” SGTP-3940, is available
tional, W. Conshohocken, PA, 1995. from Gammon Technical Products, Manasquan, NJ.
D6986–03
TABLE 2 Water Contaminant Appearance Ratings
7. Sampling
Rating Description
7.1 Sampling shall be consistent with the procedures in
Bright no suspended or visible free water, sample is bright (slight sparkle).
Practice D4057.
Air bubbles may cause hazy appearance immediately after the
7.2 Draw the sample for a field test directly into the test
sample is drawn, but haze clears from the bottom up.
container using the following procedure:
Hazy fine droplets dispersed through sample, may be temporary due to
sample cooling.
7.2.1 Ensure that the sampling valve is free of loose solid
Cloudy fine droplets dispersed through sample, giving it milky appearance.
contaminants. If rust or other loose encrustation is present,
Wet droplets or water layer on bottom of container or clinging to sides.
remove with a cloth; then flush the sampling valve prior to
taking the actual sample.
7.2.2 Ensure the displacement the fuel volume in the piping
bottom of the container. Directly facing the container and bar
between the sample tap and the storage tank This displacement
chart, compare the appearance of the bar chart through the
volume should be discarded as it may not be representative of
sample with the standard photographs. Place the photographs
the fuel to be tested.
next to the container so that they are lighted similarly to the
7.2.2.1 All fluid obtained from a filter sump should be kept
sample. Select the photograph closest in appearance to the
as the sample.
sample. Notice that the differences between photographs con-
7.2.3 Rinse a clean test container thoroughly with the fuel
sist both of the successive disappearance of lines as well as the
being sampled. (Warning—Flammable, keep away from heat,
gradual lightening of all the lines. Record the number of the
sparks, and open flames.)
thinnest line which is visible through the sample, or record
7.2.4 Draw the sample continuously, opening the valve
“six” if no lines are visible.
completely to obtain a full flush. Do not open or close taps or
8.1.2 Closed Circuit Sampler:
valves during sample draw as this action can affect sample
8.1.2.1 With fuel flowing under pressure in the main fuel
quality.
line, open the fill valve wide, filling the glass jar to within
7.3 If the test is to be conducted on fuel taken in a separate
about 25 mm (1 in.) from the top.
container for laboratory testing, the container should be shaken
8.1.2.2 Lettheproductsettlefor1minormore,ifnecessary,
vigorously before decanting the fuel into the viewing equip-
toremoveairbubbles.(Caution—Thevisualresultsmaydiffer
ment.Sampletransfershouldberapidenoughtoavoidchanges
from the photographs if the circuit sampler has a diameter
in sample temperature.
different from that of the 100 mm (4 in.) jar used in the
photographs.)
8. Procedures
8.1.2.3 Examine the glass sampler for hazy/cloudy condi-
8.1 Procedure A—Clear, Transparent Containers:
tions and the bottom for water droplets, solid contaminants,
8.1.1 Open Glass or Plastic Container:
brown slimes, or a combination thereof. Record the particulate
8.1.1.1 Visual Observation—Fill container about three-
and water appearance ratings of the sample using the ratings in
fourths full. Immediately check for evidence of water or
Tables 1 and 2. Record the appearance of any other contami-
particulate contamination by holding the sample to the light
nant using Table 3 as a guide. If desired, the bar chart and
and visually examining for haze or lack of clarity. Close the
photos can be used to rate sample clarity as described in
container and swirl the sample to produce a vortex and
8.1.1.2. Record the ambient temperature.
examine the bottom of the vortex for particulate matter and
NOTE 3—While small water droplets and air bubbles may appear
water droplets. Also look for brown slime or a water layer on
similar,airbubbleswillrisewhilewaterdropletswillsettleuponstanding.
the bottom of the container. Record the particulate and water
8.1.2.4 If the sampler is fitted with an optional self-sealing
appearance rating of the sample using the ratings in Tables 1
valve assembly for a free water field testing kit, a fuel sample
and 2. Record the appearance of any other contaminant using
may be drawn at this time.
Table 3 as a guide.
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