ASTM D5972-99a
(Test Method)Standard Test Method for Freezing Point of Aviation Fuels (Automatic Phase Transition Method)
Standard Test Method for Freezing Point of Aviation Fuels (Automatic Phase Transition Method)
SCOPE
1.1 This test method covers the determination of the temperature below which solid hydrocarbon crystals form in aviation turbine fuels.
1.2 This test method is designed to cover the temperature range of -80 to 20°C; however, the ASTM interlaboratory study mentioned in 12.4 has only demonstrated the test method with fuels having freezing points in the range of -45 to 65°C.
1.3 The user shall exercise appropriate caution when this test method is used in testing Jet B and JP 4 samples (see 12.3).
1.4 The values stated in SI units are to be regarded as the standard.
1.5 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 determine the applicability of regulatory limitations prior to use. For specific hazard statements see 7.1, 7.3, and 7.5.
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Designation: D 5972 – 99a An American National Standard
Designation: 435/98
Standard Test Method for
Freezing Point of Aviation Fuels (Automatic Phase
Transition Method)
This standard is issued under the fixed designation D 5972; 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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope ture at which the solid hydrocarbon crystals completely redis-
solve into the liquid phase.
1.1 This test method covers the determination of the tem-
3.3.2 Peltier device, n—a solid-state thermoelectric device
perature below which solid hydrocarbon crystals form in
constructed with dissimilar semiconductor materials, config-
aviation turbine fuels.
ured in such a way that it will transfer heat to and away from
1.2 This test method is designed to cover the temperature
a test specimen dependent on the direction of electric current
range of −80 to 20°C; however, the ASTM interlaboratory
applied to the device.
study mentioned in 12.4 has only demonstrated the test method
with fuels having freezing points in the range of −45 to −65°C.
4. Summary of Test Method
1.3 The user shall exercise appropriate caution when this
4.1 A specimen is cooled at a rate of 15 6 5°C/min by a
test method is used in testing Jet B and JP 4 samples (see 12.3).
Peltier device while continuously being illuminated by a light
1.4 The values stated in SI units are to be regarded as the
source. The specimen is continuously monitored by an array of
standard.
optical detectors for the first formation of solid hydrocarbon
1.5 This standard does not purport to address all of the
crystals. Once the hydrocarbon crystals are formed, the speci-
safety concerns, if any, associated with its use. It is the
men is then warmed at a rate of 10 + 0.5°C/min until the last
responsibility of the user of this standard to establish appro-
hydrocarbon crystals return to the liquid phase. The detectors
priate safety and health practices and determine the applica-
are sufficient in number to ensure that any solid hydrocarbon
bility of regulatory limitations prior to use. For specific hazard
crystals are detected. The specimen temperature at which the
statements see 7.1, 7.3, and 7.5.
last hydrocarbon crystals return to the liquid phase is recorded
2. Referenced Documents as the freezing point.
2.1 ASTM Standards:
5. Significance and Use
D 2386 Test Method for Freezing Point of Aviation Fuels
5.1 The freezing point of an aviation fuel is the lowest
3. Terminology temperature at which the fuel remains free of solid hydrocar-
bon crystals. These crystals can restrict the flow of fuel through
3.1 Definitions:
the fuel system of the aircraft. The temperature of the fuel in
3.2 freezing point, n—in aviation fuels, the fuel temperature
the aircraft tank normally decreases during flight depending on
at which solid hydrocarbon crystals, formed on cooling,
aircraft speed, altitude, and flight duration. The freezing point
disappear when the temperature of the fuel is allowed to rise.
of the fuel must always be lower than the minimum operational
3.3 Definitions of Terms Specific to This Standard:
fuel temperature.
3.3.1 automatic phase transition method, n—in this test
5.2 Petroleum blending operations require precise measure-
method, the procedures of automatically cooling a liquid
ment of the freezing point.
aviation fuel specimen until solid hydrocarbon crystals appear,
5.3 This test method produces results which have been
followed by controlled warming and recording of the tempera-
found to be equivalent to Test Method D 2386 and expresses
results to the nearest 0.1°C, with improved precision over Test
This test method is under the jurisdiction of ASTM Committee D-2 on
Method D 2386. This test method also eliminates most of the
Petroleum Products and Lubricants and is the direct responsibility of Subcommittee
operator time and judgment required by Test Method D 2386.
D02.07.0D on Wax-Related Viscometric Properties of Fuels and Oils.
Current edition approved Dec. 10, 1999. Published January 2000. Originally 5.4 When specification requires Test Method D 2386, do not
published as D 5972 — 96. Last previous edition D 5972 — 99.
substitute this test method or any other test method.
Annual Book of ASTM Standards, Vol 05.01.
Copyright © ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, United States.
D 5972
6. Apparatus 8.2 Turn on the liquid cooling medium and ensure its
temperature is appropriate for the specimen being tested in
6.1 Automatic Apparatus —This apparatus consists of a
accordance with the manufacturer’s instructions (see Note 1).
microprocessor-controlled test chamber that is capable of
8.3 Turn on the purge gas and ensure that it is regulated to
cooling and heating the test specimen, optically observing the
the appropriate pressure in accordance with the manufacturer’s
appearance and disappearance of solid hydrocarbon crystals,
instructions.
and recording the temperature of the specimen. A detailed
8.4 Turn on the main power switch of the analyzer.
description of the apparatus is provided in Annex A1.
6.2 The apparatus shall be equipped with a specimen cup,
9. Calibration and Standardization
optical detector array, light source, digital display, Peltier
9.1 Ensure that all of the manufacturer’s instructions for
device, and a specimen temperature measuring device.
calibrating, checking, and operating the apparatus are fol-
6.3 The temperature measuring device in the specimen cup
lowed.
shall be capable of measuring the temperature of the test
9.2 An aviation turbine fuel sample which has been exten-
specimen from −80 to +20°C at a resolution of 0.1°C and
sively tested in a Test Method D 2386 interlaboratory study can
accuracy of 0.1°C.
be used to verify performance of the apparatus within the
6.4 The apparatus shall be equipped with fittings to permit
precision of the test method.
the circulation of a liquid medium to remove heat generated by
9.3 Reagent grade n-octane with a known freezing point
the Peltier device and other electronic components of the
value can be used to verify the calibration of the specimen
apparatus.
temperature measuring device within the precision of this test
6.5 The apparatus shall be equipped with fittings to permit
method. The literature value for the freezing point of pure
the circulation of purge gas to purge the test chamber contain-
n-octane is −56.8°C.
ing the specimen cup of any atmospheric moisture.
10. Procedure
7. Reagents and Materials
10.1 Open the test chamber lid and clean the specimen cup
7.1 n-Octane—Reagent grade is suitable. (Warning—
inside the test chamber with a cotton swab.
Flammable. Harmful if inhaled. Keep away from heat, sparks,
10.2 Rinse the specimen cup by pipetting 0.15 6 0.01 mL of
and open flame.)
specimen into the cup. Clean the specimen out of the cup by
7.2 Cooling Medium—Liquid heat exchange medium to
using a cotton swab. The cup should be cleaned to the point
remove the heat generated by the Peltier device and other
where no visible droplets of specimen remain in the cup.
electronic components from the apparatus.
10.3 Rinse the cup a second time by repeating 10.2.
NOTE 1—Some apparatus are designed to use tap water as a cooling
10.4 Carefully measure 0.15 6 0.01 mL of specimen into
medium to bring the specimen temperature to −60°C. To achieve cooling
the specimen cup.
of the specimen to −80°C, provide circulation of the cooling medium at
10.5 Close and lock the test chamber lid.
−30°C or lower to the apparatus. Since water freezes at 0°C, a commercial
10.6 Start the operation of the apparatus according to the
or technical grade isopropanol (see Note 1) is suitable as the cooling
medium. Refer to the manufacturer’s operating instructions on the manufacturer’s instructions. From this point up to and includ-
relationship between the cooling medium temperature and the minimum
ing the termination of the measurement, the apparatus auto-
specimen temperature.
matically controls all operations. Purge gas and liquid cooling
7.3 Purge Gas—A gas such as air, nitrogen, helium, or medium will begin to flow through the apparatus. The Peltier
device cools the specimen at a rate of 15 6 5°C/min. The
argon with a dew point below the lowest temperature attained
by the specimen under the conditions of the test. (Warning— optical detectors continuously monitor the specimen for the
Compressed gas under high pressure.) (Warning—Inert gas formation of hydrocarbon crystals. The temperature of the
can be an asphyxiant when inhaled. specimen is continuously monitored by the apparatus and
7.4 Pipette, capable of dispensing 0.15 6 0.01 mL of displayed on its front panel. Once hydrocarbon crystals are
sample. detected, the specimen is then warmed at 10 6 0.5°C/min until
7.5 Cotton Swabs—Plastic- or paper-shaft cotton swabs to all the crystals redissolve into the liquid phase. When the
clean the specimen cup. (Warning—The use of swabs with disappearance of the last crystals is detected, the specimen
wooden shafts may damage the mi
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