ASTM D7153-05(2010)
(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 D2386.
When a specification requires Test Method D2386, 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 20°C; 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 -42°C.
1.3 The values stated in SI units 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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.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(Reapproved 2010)
IP 529
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
range of -80 to 20°C; however, the interlaboratory study
3.2.1 automatic laser method, n—the procedures of auto-
mentioned in 12.4 has only demonstrated the test method with
matically cooling a liquid aviation fuel specimen until solid
fuels having freezing points in the range of -60 to -42°C.
hydrocarbon crystals appear, followed by controlled warming
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
standard.
3.3 Symbols:
1.4 This standard does not purport to address all of the
Cd = the specimen temperature at which the appearance of
safety concerns, if any, associated with its use. It is the
the first crystals are detected in the specimen by an
responsibility of the user of this standard to establish appro-
optical crystal detector under specified conditions of
priate safety and health practices and to determine the
test.
applicability of regulatory limitations prior to use.
Co = the specimen temperature at which the appearance of
opacity in the specimen is detected by an optical
2. Referenced Documents
opacity detector under specified conditions of test.
2.1 ASTM Standards:
Do = the specimen temperature at which the disappearance
D2386 Test Method for Freezing Point of Aviation Fuels
of opacity in the specimen is detected by an optical
D4057 Practice for Manual Sampling of Petroleum and
opacity detector under specified conditions of test.
Petroleum Products
D4177 Practice for Automatic Sampling of Petroleum and
4. Summary of Test Method
Petroleum Products
4.1 A specimen is cooled at a rate of 10 6 5°C/min while
2.2 Energy Institute Standard:
continuously being illuminated by a laser light source. The
IP 16 Determination Freezing Point of Aviation Fuels
specimen is continuously monitored by optical crystal and
3. Terminology opacity detectors for the first formation of solid hydrocarbon
crystals. Once the hydrocarbon crystals are detected by both
3.1 Definitions:
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
1 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 May 1, 2010. Published May 2010. Originally
crystal detector, is recorded as the freezing point.
approved in 2005. Last previous edition approved in 2005 as D7152–05. DOI:
10.1520/D7153-05R10.
2 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 (2010)
phase. The specimen temperature at which the last hydrocar- 6.6 Waste Receiving Container, capable of collecting the
bon crystals return to the liquid phase, as detected by the overflow when the specimen is injected into the test cell. A
crystal detector, is recorded as the freezing point. 400-mL standard glass beaker has been found suitable.
7. Sampling
5. Significance and Use
7.1 Obtain a sample in accordance with Practice D4057 or
5.1 The freezing point of an aviation fuel is the lowest
D4177.
temperature at which the fuel remains free of solid hydrocar-
bon crystals which, if present in the fuel system of the aircraft,
7.2 At least 30 mL of sample is required for each test.
can restrict the flow of fuel through filters. The temperature of
the fuel in the aircraft tank normally decreases during flight
8. Preparation of Apparatus
depending on aircraft speed, altitude, and flight duration. The
8.1 Install the apparatus for operation in accordance with
freezing point of the fuel shall always be lower than the
the manufacturer’s instructions.
minimum operational fuel temperature.
8.2 Turn on the main power switch of the analyzer.
5.2 Petroleum blending operations require precise measure-
ment of the freezing point.
9. Calibration and Standardization
5.3 This test method expresses results to the nearest 0.1°C,
9.1 Ensure that all of the manufacturer’s instructions for
and it eliminates most of the operator time and judgment
calibration of the mechanical and electronic systems and
required by Test Method D2386.
operation of the apparatus are followed.
5.4 When a specification requires Test Method D2386,do
9.2 To verify the performance of the apparatus, an aviation
not substitute this test method or any other test method.
turbine fuel sample for which extensive data has been obtained
by Test Method D2386 may be used. Samples such as those
6. Apparatus
used in theASTM interlaboratory cross–check program would
6.1 Automatic Apparatus —This apparatus consists of a
meet this criterion. Such verification materials can also be
microprocessor-controlled test cell that is capable of cooling prepared from intra-company cross–checks.
and heating the specimen, dual optical detectors to monitor the
10. Procedure
appearance and disappearance of crystals and opacity, and
recording the temperature of the specimen.Adetailed descrip-
10.1 Draw 10 6 2 mL bubble-free portion of sample into a
tion of the apparatus is provided in Annex A1.
syringe.Connectthesyringetotheinletport(Fig.1).Rinsethe
test cell by injecting 10 6 2 mL of specimen into the test cell;
6.2 The apparatus shall be equipped with a specimen
chamber, optical detectors, laser light source, digital display, the specimen excess will flow into the waste receiving con-
tainer (Fig. 2)
cooling and heating systems, and a specimen temperature
measuring device.
10.2 Rinse the test cell a second time by repeating 10.1.
6.3 The temperature measuring device in the specimen
chamber shall be capable of measuring the temperature of the
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.
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 (2010)
10.4 Connect the syringe to the inlet port (Fig. 1). Dispense
the specimen into the test cell; the specimen excess will flow
into the waste receiving container (Fig. 2). Leave the syringe
connected to the sample inlet for the entire duration of the test.
10.5 Start the operation of the apparatus according the
manufacturer’s instructions. From this point through Section
11, the apparatus automatically controls the procedure.
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
FIG. 2 Waste Container
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-
10.3 Draw a 10 6 2 mL bubble-free portion of sample into
a syringe. perature at which the first crystals were detected (Cd). When
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 (2010)
the recorded temperature is warmer than the (Cd) temperature, 12.1.1 Repeatability—The difference between two test re-
it is recorded as the freezing point. sults obtained by the same operator with the same apparatus
under constant operating conditions on identical test material
NOTE 3—In most cases, 10.5.3 is considered the termination of the test.
would, in the long run, in the normal and correct operation of
(See 10.5.4.)
this test method, exceed 0.6°C only in one case in twenty.
10.5.4 In certain circumstances, as measured by the
12.1.2 Reproducibility—The difference between two single
apparatus, perform a second test cycle as follows in 10.6.
and independent results obtained by different operators work-
NOTE4—Thiscircumstancemayindicatethepresenceofcontamination
ing in different laboratories on identical test material would, in
of the specimen with material other than aviation fuel and the stated
the long run, in the normal and correct operation of this test
precisions may not apply.
method, exceed 0.9°C only in one case in twenty.
10.6 Second Test Cycle:
10.6.1 The original specimen is warmed up to approxi-
12.2 Bias—Because there are no liquid hydrocarbon mix-
mately 10°C and then cooled at a rate of 10 6 5°C/min while
tures of known freezing point, which simulate aviation fuels,
continuously being illuminated by a polarized laser light
bias cannot be established.
source. Monitor the specimen continuously with the optical
12.3 Relative Bias—The results for all the samples from the
crystal detector (Fig. 3) for the first formation of solid
interlaboratory program were examined for biases relative to
hydrocarbon crystals.
Test Method D2386 and IP 16. A systemic bias was observed
10.6.2 Once the appearance of the first crystals (Cd) are
and is quantified with the following equation:
detected on the crystal detector, continue to cool the specimen
an additional 5°C and then discontinue the cooling.
D2386 and IP 16 5 X 2 0.347 (1)
10.6.3 Warm the specimen a rate of 12 6 l°C/min while it
where:
is still monitored by the crystal detector. When the disappear-
D2386 and IP 16 = mean of the result tested by D2386 and
ance of the last crystals is detected on the crystal detector,
IP 16.
record the specimen temperature at which the last hydrocarbon
X = mean of the result tested by this test
crystals return to the liquid phase as the freezing point.
method (D7153).
NOTE 5—When condition described in 10.5.4 is encountered, this
12.3.1 As example: For a D2386 and IP 16 result of -60°C,
indicates that the sample may be contaminated. In that case, in order to
minimize the test duration, only the 12 6 1°C warming rate is used. the result from this test method is -59.65°C , or 0.347°C
warmer than the D2386 and IP 16 result.
10.7 Once the freezing point is recorded, the test cell is
warmed up to ambient temperature.Fig. A1.5 gives two ex- 12.3.2 However, the relative bias is within the reproducibil-
amples of the testing process: one with a neat jet fuel, and one
ity of both test methods.
with a contaminated jet fuel.
12.3.3 The cross method reproducibility (Rxy), identified in
the research report, between this test method andTest Method
10.8 The freezing point value will be automatically rounded
to the nearest 0.1°C and displayed by the apparatus. D2386 is 1.9. (See research report for further information on
relative bias and the methods used to derive them.)
10.9 Disconnect the injection syringe from the sample inlet.
The cleaning of the test cell will be carried out during the
12.4 The precision statements were derived from a 2003
performance of the next test.
interlaboratory cooperative test program. Participants ana-
lyzed 13 samples sets comprised of various aviation fuels over
11. Report
the temperature range of -42 to -60°C. Thirteen laboratories
11.1 Report the temperature recorded in 10.8 as the freezing
participated with the automatic laser method and fifteen with
point,
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