ASTM D7153-05
(Test Method)Standard Test Method for Freezing Point of Aviation Fuels (Automatic Laser Method)
Standard Test Method for Freezing Point of Aviation Fuels (Automatic Laser Method)
SIGNIFICANCE AND USE
The freezing point of an aviation fuel is the lowest temperature at which the fuel remains free of solid hydrocarbon crystals which, if present in the fuel system of the aircraft, can restrict the flow of fuel through filters. The temperature of the fuel in the aircraft tank normally decreases during flight depending on aircraft speed, altitude, and flight duration. The freezing point of the fuel shall always be lower than the minimum operational fuel temperature.
Petroleum blending operations require precise measurement of the freezing point.
This test method expresses results to the nearest 0.1°C, and it eliminates most of the operator time and judgment required by Test Method D 2386.
When a specification requires Test Method D 2386, do not substitute this test method or any other test method.
SCOPE
1.1 This test method covers the determination of the temperature below which solid hydrocarbon crystals may form in aviation turbine fuels.
1.2 This test method is designed to cover the temperature range of -80 to 20C; however, the interlaboratory study mentioned in 12.4 has only demonstrated the test method with fuels having freezing points in the range of -60 to -42C.
1.3 The values stated in SI unitsa are to be regarded as standard. No other units of measurement are included in this standard.
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and to determine the applicability of regulatory limitations prior to use.
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Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation:D7153–05
IP529
Standard Test Method for
Freezing Point of Aviation Fuels (Automatic Laser Method)
This standard is issued under the fixed designation D7153; 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.
1. Scope 3.1.1 freezing point, n—in aviation fuels, the fuel tempera-
ture at which solid hydrocarbon crystals, formed on cooling,
1.1 This test method covers the determination of the tem-
disappear when the temperature of the fuel is allowed to rise
perature below which solid hydrocarbon crystals may form in
under specified conditions of test.
aviation turbine fuels.
3.2 Definitions of Terms Specific to This Standard:
1.2 This test method is designed to cover the temperature
3.2.1 automatic laser method, n—the procedures of auto-
range of -80 to 20°C; however, the interlaboratory study
matically cooling a liquid aviation fuel specimen until solid
mentioned in 12.4 has only demonstrated the test method with
hydrocarbon crystals appear, followed by controlled warming
fuels having freezing points in the range of -60 to -42°C.
and recording of temperature at which hydrocarbon crystals
1.3 The values stated in SI units are to be regarded as
completely redissolve into the liquid phase.
standard. No other units of measurement are included in this
3.3 Symbols:
standard.
1.4 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
Cd = the specimen temperature at which the appearance of
responsibility of the user of this standard to establish appro-
the first crystals are detected in the specimen by an
priate safety and health practices and to determine the
optical crystal detector under specified conditions of
applicability of regulatory limitations prior to use.
test.
Co = the specimen temperature at which the appearance of
2. Referenced Documents
opacity in the specimen is detected by an optical
2.1 ASTM Standards:
opacity detector under specified conditions of test.
D2386 Test Method for Freezing Point of Aviation Fuels
Do = the specimen temperature at which the disappearance
D4057 Practice for Manual Sampling of Petroleum and
of opacity in the specimen is detected by an optical
Petroleum Products
opacity detector under specified conditions of test.
D4177 Practice for Automatic Sampling of Petroleum and
Petroleum Products 4. Summary of Test Method
2.2 Energy Institute Standard:
4.1 A specimen is cooled at a rate of 10 6 5°C/min while
IP 16 Determination Freezing Point of Aviation Fuels
continuously being illuminated by a laser light source. The
specimen is continuously monitored by optical crystal and
3. Terminology
opacity detectors for the first formation of solid hydrocarbon
3.1 Definitions:
crystals. Once the hydrocarbon crystals are detected by both
sets of optical detectors, the specimen is then warmed at a rate
of 3 6 0.5°C/min. When initial opacity in the specimen
disappears, the specimen is then warmed at a rate of 12 6
This test method is under the jurisdiction of ASTM Committee D02 on
Petroleum Products and Lubricants and is the direct responsibility of Subcommittee
l°C/min. The specimen temperature at which the last hydro-
D02.07 on Flow Properties.
carbon crystals return to the liquid phase, as detected by the
Current edition approved July 1, 2005. Published July 2005. DOI: 10.1520/
crystal detector, is recorded as the freezing point.
D7153-05.
4.2 In certain circumstances, as measured by the apparatus,
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
the specimen is reheated to approximately 10°C, then cooled at
Standards volume information, refer to the standard’s Document Summary page on
the rate in 4.1 until hydrocarbon crystals are detected by the
the ASTM website.
3 crystaldetector.Thespecimenisthenwarmedatarateof12 6
Annual Book of IP Standards Methods, Vol 1.Available from Energy Institute,
61 New Cavendish St., London, WIG 7AR, U.K. l°C/min, until the last hydrocarbon crystals return to the liquid
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D7153–05
phase. The specimen temperature at which the last hydrocar- 7. Sampling
bon crystals return to the liquid phase, as detected by the
7.1 Obtain a sample in accordance with Practice D4057 or
crystal detector, is recorded as the freezing point.
D4177.
7.2 At least 30 mL of sample is required for each test.
5. Significance and Use
5.1 The freezing point of an aviation fuel is the lowest
8. Preparation of Apparatus
temperature at which the fuel remains free of solid hydrocar-
8.1 Install the apparatus for operation in accordance with
bon crystals which, if present in the fuel system of the aircraft,
the manufacturer’s instructions.
can restrict the flow of fuel through filters. The temperature of
8.2 Turn on the main power switch of the analyzer.
the fuel in the aircraft tank normally decreases during flight
depending on aircraft speed, altitude, and flight duration. The
9. Calibration and Standardization
freezing point of the fuel shall always be lower than the
9.1 Ensure that all of the manufacturer’s instructions for
minimum operational fuel temperature.
calibration of the mechanical and electronic systems and
5.2 Petroleum blending operations require precise measure-
operation of the apparatus are followed.
ment of the freezing point.
9.2 To verify the performance of the apparatus, an aviation
5.3 This test method expresses results to the nearest 0.1°C,
turbine fuel sample for which extensive data has been obtained
and it eliminates most of the operator time and judgment
by Test Method D2386 may be used. Samples such as those
required by Test Method D2386.
used in theASTM interlaboratory cross–check program would
5.4 When a specification requires Test Method D2386,do
meet this criterion. Such verification materials can also be
not substitute this test method or any other test method.
prepared from intra-company cross–checks.
6. Apparatus
10. Procedure
6.1 Automatic Apparatus —This apparatus consists of a
10.1 Draw 10 6 2 mL bubble-free portion of sample into a
microprocessor-controlled test cell that is capable of cooling
syringe.Connectthesyringetotheinletport(Fig.1).Rinsethe
and heating the specimen, dual optical detectors to monitor the
test cell by injecting 10 6 2 mL of specimen into the test cell;
appearance and disappearance of crystals and opacity, and
the specimen excess will flow into the waste receiving con-
recording the temperature of the specimen.Adetailed descrip-
tainer (Fig. 2)
tion of the apparatus is provided in Annex A1.
10.2 Rinse the test cell a second time by repeating 10.1.
6.2 The apparatus shall be equipped with a specimen
10.3 Draw a 10 6 2 mL bubble-free portion of sample into
chamber, optical detectors, laser light source, digital display,
a syringe.
cooling and heating systems, and a specimen temperature
10.4 Connect the syringe to the inlet port (Fig. 1). Dispense
measuring device.
the specimen into the test cell; the specimen excess will flow
6.3 The temperature measuring device in the specimen
into the waste receiving container (Fig. 2). Leave the syringe
chamber shall be capable of measuring the temperature of the
connected to the sample inlet for the entire duration of the test.
specimen from -80 to +20°C at a resolution of 0.1°C and
accuracy of 0.1°C.
6.4 The apparatus shall be capable of cooling the specimen
at a rate of 10 6 5°C/min, heating the specimen at rates of 3 6
0.5°C/minand12 61°C/minoverthetemperaturerangeof-80
to +20°C.
NOTE 1—The apparatus described is covered by a patent. If you are
aware of an alternative(s) to the patented item, please attach to your ballot
return a description of the alternatives.All suggestions will be considered
by the committee.
NOTE 2—The software version used in this apparatus is version V 5.3.
6.5 Standard Syringe,capableofinjectingapproximately10
6 2 mL of the specimen, with a tip or an adapter tip that will
fit the inlet of the test cell. A disposable 10-mL syringe with a
Luer type cone connection has been found suitable.
6.6 Waste Receiving Container, capable of collecting the
overflow when the specimen is injected into the test cell. A
400-mL standard glass beaker has been found suitable.
The sole source of supply of the apparatus known to the committee at this time
is ISL model FZP 5G2s series Freezing Point Analyzer, available from PAC - ISL,
BP 70285 - VERSON, 14653 CARPIQUET Cedex, France. If you are aware of
alternative suppliers, please provide this information to ASTM International
Headquarters.Your comments will receive careful consideration at a meeting of the
responsible technical committee, which you may attend. FIG. 1 Syringe Inserted in Inlet Port
D7153–05
10.5.1 Cool the specimen at a rate of 10 6 5°C/min while
continuously illuminating with a polarized laser light source.
Monitor the specimen continuously with two optical detectors,
an opacity detector and a crystal detector (Fig. 3), for the first
formation of solid hydrocarbon crystals.
10.5.2 Once the appearance of the first crystals (Cd)is
detected on the crystal detector and opacity (Co) is detected on
the opacity detector, warm the specimen at a rate of 3 6
0.5°C/min until the disappearance of the opacity (Do)is
detected on the opacity detector. At that point, warm the
specimen at a rate of 12 6 l°C/min while it is still monitored
by the crystal detector. When the disappearance of the last
crystals is detected on the crystal detector, record the specimen
temperatureatwhichthelasthydrocarboncrystalsreturntothe
liquid phase. Refer to A1.2.12 and Fig. A1.5 for detection
curve examples.
10.5.3 Compare this recorded temperature with the tem-
perature at which the first crystals were detected (Cd). When
the recorded temperature is warmer than the (Cd) temperature,
it is recorded as the freezing point.
FIG. 2 Waste Container
NOTE 3—In most cases, 10.5.3 is considered the termination of the test.
(See 10.5.4.)
10.5 Start the operation of the apparatus according the
manufacturer’s instructions. From this point through Section 10.5.4 In certain circumstances, as measured by the appa-
11, the apparatus automatically controls the procedure. ratus, perform a second test cycle as follows in 10.6.
where:
1 = Specimen chamber
2 = Temperature probe
3 = Specimen test cell
4&5 = Specimen inlet and outlet
6 = Laser
7 = Crystal detector (see solid line curve in Fig. A1.5)
9&11 = Polarization filters
10 = Windows
12 = Opacity detector (see dotted line curve in Fig. A1.5)
FIG. 3 Principle of Detection
D7153–05
NOTE 4—This circumstance may indicate the presence of contamina-
under constant operating conditions on identical test material
tion of the specimen with material other than aviation fuel and the stated
would, in the long run, in the normal and correct operation of
precisions may not apply.
this test method, exceed 0.6°C only in one case in twenty.
10.6 Second Test Cycle:
12.1.2 Reproducibility—The difference between two single
10.6.1 The original specimen is warmed up to approxi-
and independent results obtained by different operators work-
mately 10°C and then cooled at a rate of 10 6 5°C/min while
ing in different laboratories on identical test material would, in
continuously being illuminated by a polarized laser light
the long run, in the normal and correct operation of this test
source. Monitor the specimen continuously with the optical
method, exceed 0.9°C only in one case in twenty.
crystal detector (Fig. 3) for the first formation of solid
12.2 Bias—Because there are no liquid hydrocarbon mix-
hydrocarbon crystals.
tures of known freezing point, which simulate aviation fuels,
10.6.2 Once the appearance of the first crystals (Cd) are
bias cannot be established.
detected on the crystal detector, continue to cool the specimen
12.3 Relative Bias—The results for all the samples from the
an additional 5°C and then discontinue the cooling.
interlaboratory program were examined for biases relative to
10.6.3 Warm the specimen a rate of 12 6 l°C/min while it
Test Method D2386 and IP 16. A systemic bias was observed
is still monitored by the crystal detector. When the disappear-
and is quantified with the following equation:
ance of the last crystals is detected on the crystal detector,
D2386 and IP 16 5 X 2 0.347 (1)
record the specimen temperature at which the last hydrocarbon
crystals return to the liquid phase as the freezing point.
where:
D2386 and = mean of the result tested by D2386 and
NOTE 5—When condition described in 10.5.4 is encountered, this
IP 16 IP 16.
indicates that the sample may be contaminated. In that case, in order to
X = mean of the result tested by this test
minimize the test duration, only the 12 6 1°C warming rate is used.
method (D7153).
10.7 Once the freezing point is recorded, the test cell is
12.3.1 As example: For a D2386 and IP 16 result of -60°C,
warmed up to ambient temperature.Fig. A1.5 gives two ex-
the result from this test method is -59.65°C , or 0.347°C
amples of the testing process: one with a neat jet fuel, and one
warmer than the D2386 and IP 16 result.
with a contaminated jet fuel.
12.3.2 However, the relative bias is within the reproducibil-
10.8 The freezing point value will be automatically rounded
ity of both test methods.
to the nearest 0.1°C and displayed by the apparatus.
12.3.3 The cross method reproducibility (Rxy), identified in
10.9 Disconnect the injection syringe from the sample inlet.
the research report, between this test method andTest Method
The cleaning of the test cell will be carried out during the
D2386 is 1.9. (See research report for further information on
performance of the next test.
relative bias and the methods used to derive them.)
11. Report 12.4 The precision statements were derived from a 2003
interlaboratory cooperative test program. Participants ana-
11.1 Report the temperature recorded in 10.8 as the freezing
lyzed 13 samples sets comprised of various aviation fuels over
point, determined by Test Method D7153.
the temperature range of -42 to -60°C. Thirteen laboratories
12. Precision and Bias
participated with the automatic laser method and fifteen with
the manual D2386 or IP 16 test methods. The precision
12.1 Precision—The precision of this test method as deter-
statistics were compiled and calculated based on the 0.1°C
m
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