ASTM D7525-14(2019)e1
(Test Method)Standard Test Method for Oxidation Stability of Spark Ignition Fuel—Rapid Small Scale Oxidation Test (RSSOT)
Standard Test Method for Oxidation Stability of Spark Ignition Fuel—Rapid Small Scale Oxidation Test (RSSOT)
SIGNIFICANCE AND USE
5.1 The induction period may be used as an indication of the oxidation and storage stability of spark ignition fuel.
5.2 Compared to some other oxidation and storage stability test methods, this test method uses a small sample and gives a result in a short time period.
SCOPE
1.1 This laboratory test method covers the quantitative determination of the stability of spark ignition fuel, including those containing alcohols or other oxygenates, under accelerated oxidation conditions, by an automatic instrument (Warning—This test method is not intended for determining the stability of gasoline components, particularly those with a high percentage of low boiling unsaturated compounds, as these can cause explosive conditions with the apparatus.2)
1.2 This test method measures the induction period, under specified conditions, which can be used as an indication of the oxidation and storage stability of spark ignition fuel.
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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.
1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
General Information
Relations
Standards Content (Sample)
This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
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Designation: D7525 − 14 (Reapproved 2019)
Standard Test Method for
Oxidation Stability of Spark Ignition Fuel—Rapid Small
Scale Oxidation Test (RSSOT)
This standard is issued under the fixed designation D7525; 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.
ε NOTE—Editorially updated Footnote 4 and Fig. 1 in December 2019.
1. Scope 2. Referenced Documents
2.1 ASTM Standards:
1.1 This laboratory test method covers the quantitative
D4057 Practice for Manual Sampling of Petroleum and
determination of the stability of spark ignition fuel, including
Petroleum Products
those containing alcohols or other oxygenates, under acceler-
D4177 Practice for Automatic Sampling of Petroleum and
ated oxidation conditions, by an automatic instrument
Petroleum Products
(Warning—This test method is not intended for determining
D6300 Practice for Determination of Precision and Bias
the stability of gasoline components, particularly those with a
Data for Use in Test Methods for Petroleum Products and
high percentage of low boiling unsaturated compounds, as
Lubricants
these can cause explosive conditions with the apparatus. )
3. Terminology
1.2 This test method measures the induction period, under
specified conditions, which can be used as an indication of the
3.1 Definitions of Terms Specific to This Standard:
oxidation and storage stability of spark ignition fuel.
3.1.1 break point, n—pressure in the test apparatus, which is
10 % below the maximum pressure of the actual test run.
1.3 The values stated in SI units are to be regarded as
3.1.2 induction period, n—timeelapsedbetweenstartingthe
standard. No other units of measurement are included in this
heating procedure of the sample vessel and the break point,
standard.
measured in minutes.
1.4 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
4. Summary of Test Method
responsibility of the user of this standard to establish appro-
4.1 A 5 mL sample is introduced into a pressure vessel
priate safety, health, and environmental practices and deter-
which is then charged with oxygen to 500 kPa at a temperature
mine the applicability of regulatory limitations prior to use.
of15 °Cto25 °C.Thetestisinitiatedbystartingtheheaterand
1.5 This international standard was developed in accor-
heating the pressure vessel to a temperature of 140 °C.
dance with internationally recognized principles on standard-
4.2 The pressure is recorded continuously until the break-
ization established in the Decision on Principles for the
pointisreached.Alternatively,thetestmaybeterminatedwhen
Development of International Standards, Guides and Recom-
a predetermined minimum requirement is reached.
mendations issued by the World Trade Organization Technical
Barriers to Trade (TBT) Committee.
5. Significance and Use
5.1 Theinductionperiodmaybeusedasanindicationofthe
oxidation and storage stability of spark ignition fuel.
5.2 Compared to some other oxidation and storage stability
test methods, this test method uses a small sample and gives a
result in a short time period.
This test method is under the jurisdiction of ASTM Committee D02 on
Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of
Subcommittee D02.14 on Stability, Cleanliness and Compatibility of Liquid Fuels.
Current edition approved Dec. 1, 2019. Published December 2019. Originally
approved in 2009. Last previous edition approved in 2014 as D7525 – 14. DOI: For referenced ASTM standards, visit the ASTM website, www.astm.org, or
10.1520/D7525-14R19E01. contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Further information can be found in the June 1978, January 1979, and June Standards volume information, refer to the standard’s Document Summary page on
1986 editions of the Institute of Petroleum Review. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
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D7525 − 14 (2019)
6. Apparatus from the test temperature to ambient temperature by a flow of
air. See Annex A1 for detailed information.
6.1 General—This test method uses an automatically con-
trolled oxidation tester (Fig. 1) comprising an oxidation 6.2 Volumetric Device, clean and free from contaminations
of previous samples, capable of delivering 5.0 mL 6 0.1 mL.
pressure vessel containing a test sample cup capable of being
rapidly heated, fitted with a pressure sensor capable of mea-
6.3 Temperature Calibration Equipment, comprising a
suring pressures up to 2000 kPa and a temperature sensor
cover and a temperature calibration sensor (Fig. 2). The
capable of reading to 0.1 °C. Pressure and temperature in the
temperature calibration sensor is fixed to a depth of 15 mm 6
oxidation vessel are recorded continuously during the test. The
0.5 mm. The temperature calibration sensor, calibrated to the
oxidation pressure vessel is fitted with filling and relief valves
nearest 0.1 °C, is calibrated by an approved calibration service,
and a means of automatically releasing the pressure at the end
such as one that is traceable to the National Institute of
of the test. The integrated cooling fan cools the pressure vessel
Standards and Technology (NIST) or to a national authority in
the country in which the equipment is used or manufactured.
6.4 Pressure Calibration Equipment, comprising a pressure
4 calibration sensor (Fig. 3). The pressure calibration senor is
The sole source of supply of the apparatus known to the committee at this time
calibrated to the nearest 10 kPa, by an approved calibration
is Anton Paar’s RapidOxy 100 instrument (formerly PetroOxy), available from
Anton Paar ProveTec GmbH, Ludwig-Erhard-Ring 13, 15827 Blankenfelde-
service, such as one that is traceable to the National Institute of
Mahlow, Germany, www.anton-paar.com. If you are aware of alternative suppliers,
Standards and Technology (NIST) or to a national authority in
please provide this information to ASTM International Headquarters. Your com-
the country in which the equipment is used or manufactured.
ments will receive careful consideration at a meeting of the responsible technical
committee, which you may attend.
1. Safety and insulating hood
2. Screw cap for closing the test container
3. Locking/unlocking mechanism for insulating hood
4. “O-ring” seal for test sample cup
5. Test sample cup
6. Operating panel with display
7. Oxygen inlet
8. Oxygen outlet
FIG. 1 Schematic of Apparatus for Rapid Small Scale Oxidation Test
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D7525 − 14 (2019)
1. Calibration cover with duct for temperature calibration sensor
2. Calibration fluid
3. Temperature sensor for block temperature
4. Heating block
5. Immersion depth of temperature calibration sensor and bottom of
calibration cover
6. Seal
7. Temperature calibration sensor
8. Connector plug to measuring device
FIG. 2 Temperature Calibration Equipment
7. Reagents and Materials 7.2 Oxygen—Commercially available extra-dry oxygen of
not less than 99.6 % purity.
7.1 Solvent for the removal of oxidation residues from the
test vessel. The solvent shall be of suitable purity to leave no
7.3 Lint-Free Cleaning Tissue—For sensitive surfaces; that
residue on the apparatus. Ethanol of 94 % minimum purity has
will not scratch the surface.
been found to be suitable. Other solvents, such as a mixture of
7.4 “O-ring” Seal—See A1.2.
equal volumes of toluene and acetone, may be used if shown to
meet the requirements for the removal of oxidation residues 7.5 Temperature Calibration Fluid—Stable middle distillate
from the test vessel without leaving any residue in the sample fuel liquid with flash point above +60 °C and boiling-point
test cup. above +150 °C.
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D7525 − 14 (2019)
FIG. 3 Pressure Calibration Equipment
products from the previous test.
8. Hazards
10.3 Wipethetestsamplecup,thesealgrooveandthecover
8.1 (Warning—To provide protection against possible ex-
of the test vessel with lint-free cleaning tissue (7.3) soaked
plosive rupture of the pressure vessel and hazards relating to
with solvent until free of gum or other oxidation residues.
hotandflammablefuels,theapparatusshallbeoperatedbehind
an appropriate safety shield.)
10.4 Allow the test sample cup and cover to dry in air and
visually inspect for cleanliness.
9. Sampling
NOTE 2—Compressed air is generally unsuitable to speed up evapora-
9.1 Sample in accordance with Practices D4057 or D4177.
tion of solvent because it can contain traces of oil that could contaminate
the next test.
10. Preparation of Apparatus
10.5 Insert a new “O-ring” seal.
10.1 Remove the previous sample by means of a pipette or
11. Calibration
similar device.
11.1 Recalibrate the tester every 12 months for correct
10.2 Remove the used “O-ring” seal and discard.
temperature and pressure detection.
NOTE 1—To avoid contamination of the new test, it is necessary to
discard the used “O-ring” seal, because it might be soaked with oxidation 11.2 Calibration of temperature indicator.
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D7525 − 14 (2019)
11.2.1 Calibratethetemperaturesensor(A1.6)tothenearest 12.12 When the pressure release process has finished, open
0.1 °C using the temperature calibration equipment (6.3) ac- the apparatus and clean according to Section 10.
cording to A2.1.
13. Report
11.3 Calibration of pressure detector.
13.1 Report the induction period to the nearest
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