ASTM D6468-06
(Test Method)Standard Test Method for High Temperature Stability of Distillate Fuels
Standard Test Method for High Temperature Stability of Distillate Fuels
SIGNIFICANCE AND USE
This test method provides an indication of thermal oxidative stability of distillate fuels when heated to high temperatures that simulate those that may occur in some types of recirculating engine or burner fuel delivery systems. Results have not been substantially correlated to engine or burner operation. The test method can be useful for investigation of operational problems related to fuel thermal stability.
When the test method is used to monitor manufacture or storage of fuels, changes in filter rating values can indicate a relative change in inherent stability. Storage stability predictions are more reliable when correlated to longer-term storage tests, for example, Test Method D 4625, or other lower temperature, long-term tests. When fuel samples are freshly produced, aging for 180 min, instead of the traditional 90-min interval, tends to give a result correlating more satisfactorily with the above methods (see Appendix X2).
The test method uses a filter paper with a nominal porosity of 11 μm, which will not capture all of the sediment formed during aging but allows differentiation over a broad range. Reflectance ratings are also affected by the color of filterable insolubles, which may not correlate to the mass of the material filtered from the aged fuel sample. Therefore, no quantitative relationship exists between the pad rating and the gravimetric mass of filterable insolubles.
SCOPE
1.1 This test method covers relative stability of middle distillate fuels under high temperature aging conditions with limited air exposure. This test method is suitable for all No. 1 and No. 2 grades in Specifications D 396, D 975, D 2880, and D 3699 and for grades DMX and DMA in Specification D 2069. It is also suitable for similar fuels meeting other specifications.
1.2 This test method is not suitable for fuels whose flash point, as determined by Test Methods D 56, D 93, or D 3828, is less than 38C. This test method is not suitable for fuels containing residual oil.
1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
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.
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Standards Content (Sample)
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An American National Standard
Designation:D6468–06
Standard Test Method for
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High Temperature Stability of Distillate Fuels
This standard is issued under the fixed designation D 6468; 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* D 3699 Specification for Kerosine
D 3828 TestMethodsforFlashPointbySmallScaleClosed
1.1 This test method covers relative stability of middle
Cup Tester
distillate fuels under high temperature aging conditions with
D 4057 Practice for Manual Sampling of Petroleum and
limited air exposure. This test method is suitable for all No. 1
Petroleum Products
and No. 2 grades in Specifications D 396, D 975, D 2880, and
D 4625 Test Method for Middle Distillate Fuel Storage
D 3699 and for grades DMX and DMA in Specification
Stability at 43°C (110°F)
D 2069. It is also suitable for similar fuels meeting other
D 5452 Test Method for Particulate Contamination inAvia-
specifications.
tion Fuels by Laboratory Filtration
1.2 This test method is not suitable for fuels whose flash
point, as determined by Test MethodsD56,D93,or D 3828,
3. Terminology
is less than 38°C. This test method is not suitable for fuels
3.1 Definitions of Terms Specific to This Standard:
containing residual oil.
3.1.1 adherent insolubles—material that is produced in the
1.3 The values stated in SI units are to be regarded as
course of stressing distillate fuel and that adheres to the
standard. No other units of measurement are included in this
glassware after fuel has been flushed from the system.
standard.
3.1.2 filterable insolubles—material that is produced in the
1.4 This standard does not purport to address all of the
course of stressing distillate fuel and that is capable of being
safety concerns, if any, associated with its use. It is the
removed from the fuel by filtration.
responsibility of the user of this standard to establish appro-
3.1.3 inherent stability—the resistance to change when
priate safety and health practices and determine the applica-
exposed to air, but in the absence of other environmental
bility of regulatory limitations prior to use.
factors such as water, reactive metal surfaces, and dirt.
2. Referenced Documents 3.1.4 storage stability—the resistance of fuel to formation
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of degradation products when stored at ambient temperatures.
2.1 ASTM Standards:
3.1.5 thermal stability—the resistance of fuel to formation
D56 Test Method for Flash Point byTag Closed CupTester
of degradation products when thermally stressed.
D93 Test Methods for Flash Point by Pensky-Martens
Closed Cup Tester
4. Summary of Test Method
D 396 Specification for Fuel Oils
4.1 Two 50-mLvolumes of filtered middle distillate fuel are
D 975 Specification for Diesel Fuel Oils
aged for 90 or 180 min at 150°C in open tubes with air
D 1500 Test Method for ASTM Color of Petroleum Prod-
exposure.After aging and cooling, the fuel samples are filtered
ucts (ASTM Color Scale)
3 and the average amount of filterable insolubles is estimated by
D 2069 Specification for Marine Fuels
measuring the light reflectance of the filter pads. The 100 and
D 2274 Test Method for Oxidation Stability of Distillate
0 % extremes of the reflectance rating range are defined by an
Fuel Oil (Accelerated Method)
unused filter pad and a commercial black standard, respec-
D 2880 Specification for Gas Turbine Fuel Oils
tively.
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5. Significance and Use
This test method is under the jurisdiction of ASTM Committee D02 on
Petroleum Products and Lubricants and is the direct responsibility of Subcommittee
5.1 This test method provides an indication of thermal
D02.14 on Stability and Cleanliness of Liquid Fuels.
oxidative stability of distillate fuels when heated to high
Current edition approved May 1, 2006. Published May 2006. Originally
temperatures that simulate those that may occur in some types
approved in 1999. Last previous edition approved in 2004 as D 6468–99(2004).
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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
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Standards volume information, refer to the standard’s Document Summary page on Henry, C. P., “The du Pont F21 149°C (300°F) Accelerated Stability Test,”
the ASTM website. Distillate Fuel Stability and Cleanliness, ASTM STP 751, L. L. Stavinoha and C. P.
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Withdrawn. Henry, Eds., ASTM, 1981, pp. 22-33.
*A Summary of Changes section appears at the end of this standard.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
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D6468–06
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