ASTM D6468-08(2019)
(Test Method)Standard Test Method for High Temperature Stability of Middle Distillate Fuels
Standard Test Method for High Temperature Stability of Middle Distillate Fuels
SIGNIFICANCE AND USE
5.1 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.
5.2 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 D4625, 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).
5.3 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 D396, D975, D2880, and D3699. 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 D56, D93, or D3828, is less than 38 °C. 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.
1.3.1 Exception—The maximum vacuum includes inch-pound units in 6.5 and 11.2.
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.
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Designation: D6468 − 08 (Reapproved 2019)
Standard Test Method for
High Temperature Stability of Middle Distillate Fuels
This standard is issued under the fixed designation D6468; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope D396Specification for Fuel Oils
D975Specification for Diesel Fuel Oils
1.1 This test method covers relative stability of middle
D1500Test Method forASTM Color of Petroleum Products
distillate fuels under high temperature aging conditions with
(ASTM Color Scale)
limited air exposure. This test method is suitable for all No. 1
D2274TestMethodforOxidationStabilityofDistillateFuel
and No. 2 grades in Specifications D396, D975, D2880, and
Oil (Accelerated Method)
D3699. It is also suitable for similar fuels meeting other
D2880Specification for Gas Turbine Fuel Oils
specifications.
D3699Specification for Kerosine
1.2 This test method is not suitable for fuels whose flash
D3828Test Methods for Flash Point by Small Scale Closed
point, as determined by Test Methods D56, D93,or D3828,is
Cup Tester
less than 38°C. This test method is not suitable for fuels
D4057Practice for Manual Sampling of Petroleum and
containing residual oil.
Petroleum Products
1.3 The values stated in SI units are to be regarded as D4625Test Method for Middle Distillate Fuel Storage
Stability at 43°C (110°F)
standard. No other units of measurement are included in this
standard. D5452Test Method for Particulate Contamination in Avia-
tion Fuels by Laboratory Filtration
1.3.1 Exception—The maximum vacuum includes inch-
pound units in 6.5 and 11.2.
3. Terminology
1.4 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
3.1 Definitions of Terms Specific to This Standard:
responsibility of the user of this standard to establish appro-
3.1.1 adherent insolubles—material that is produced in the
priate safety, health, and environmental practices and deter-
course of stressing distillate fuel and that adheres to the
mine the applicability of regulatory limitations prior to use.
glassware after fuel has been flushed from the system.
1.5 This international standard was developed in accor-
3.1.2 filterable insolubles—material that is produced in the
dance with internationally recognized principles on standard-
course of stressing distillate fuel and that is capable of being
ization established in the Decision on Principles for the
removed from the fuel by filtration.
Development of International Standards, Guides and Recom-
3.1.3 inherent stability—the resistance to change when ex-
mendations issued by the World Trade Organization Technical
posed to air, but in the absence of other environmental factors
Barriers to Trade (TBT) Committee.
such as water, reactive metal surfaces, and dirt.
2. Referenced Documents
3.1.4 storage stability—the resistance of fuel to formation
2.1 ASTM Standards: of degradation products when stored at ambient temperatures.
D56Test Method for Flash Point by Tag Closed Cup Tester
3.1.5 thermal stability—the resistance of fuel to formation
D93Test Methods for Flash Point by Pensky-Martens
of degradation products when thermally stressed.
Closed Cup Tester
4. Summary of Test Method
This test method is under the jurisdiction of ASTM Committee D02 on
4.1 Two50mLvolumesoffilteredmiddledistillatefuelare
Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of
aged for 90min or 180min at 150°C in open tubes with air
Subcommittee D02.14 on Stability, Cleanliness and Compatibility of Liquid Fuels.
exposure.Afteragingandcooling,thefuelsamplesarefiltered
CurrenteditionapprovedMay1,2019.PublishedJuly2019.Originallyapproved
and the average amount of filterable insolubles is estimated by
in 1999. Last previous edition approved in 2013 as D6468–08 (2013). DOI:
10.1520/D6468-08R19.
measuring the light reflectance of the filter pads. The 100%
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
and0%extremesofthereflectanceratingrangearedefinedby
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
an unused filter pad and a commercial black standard, respec-
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. tively.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D6468 − 08 (2019)
3 4
grounding cables is recommended. Such an apparatus and correct
5. Significance and Use
grounding practices are described in Test Method D5452. A fritted glass
5.1 This test method provides an indication of thermal
filter holder is less preferred because of a tendency to become partially
oxidative stability of distillate fuels when heated to high
cloggedduringusesothatfilterpadsthatdonothaveuniformdepositsare
obtained. Glass filter holders that use a 75µm (200mesh) screen to
temperatures that simulate those that may occur in some types
support the filter are available; however, since the screen can be an
ofrecirculatingengineorburnerfueldeliverysystems.Results
unbonded electrostatic charge collector, these are not recommended for
have not been substantially correlated to engine or burner
use with flammable liquids.
operation. The test method can be useful for investigation of
6.5 Vacuum Source, that limits the maximum vacuum to
operational problems related to fuel thermal stability.
27kPa (200mmHg) below atmospheric pressure.The vacuum
5.2 Whenthetestmethodisusedtomonitormanufactureor
should rise to 27kPa within 10s to 15s after the sample is
storage of fuels, changes in filter rating values can indicate a
added to the filtration funnel.
relative change in inherent stability. Storage stability predic-
NOTE 2—Use of reduced vacuum improves retention of particulate on
tions are more reliable when correlated to longer-term storage
the relatively porous filter media.
tests, for example, Test Method D4625, or other lower
6.6 Reflection meter, Photovolt Model 577 Digital Reflec-
temperature, long-term tests. When fuel samples are freshly
tion Meter, complete with search unit Y with a green filter and
produced, aging for 180min, instead of the traditional 90min
polished black glass standard.
interval, tends to give a result correlating more satisfactorily
with the above methods (see Appendix X2).
NOTE 3—Other reflection meters or search units, or both, can be used,
but they are likely to provide only similar (not identical) results. For
5.3 The test method uses a filter paper with a nominal
example, Photovolt Model 577 digital reflection meter equipped with
porosity of 11µm, which will not capture all of the sediment
search unit W usually gives somewhat lower percent reflectance values.
formed during aging but allows differentiation over a broad
Correlation of these values is discussed in Appendix X1.
range. Reflectance ratings are also affected by the color of
7. Reagents and Materials
filterableinsolubles,whichmaynotcorrelatetothemassofthe
material filtered from the aged fuel sample. Therefore, no
7.1 Purity of Reagents—Reagent grade chemicals shall be
quantitative relationship exists between the pad rating and the
used in all tests. Unless otherwise indicated, it is intended that
gravimetric mass of filterable insolubles.
all reagents conform to the specifications of the Committee on
Analytical Reagents of theAmerican Chemical Society where
6. Apparatus
such specifications are available. Other grades may be used,
provided it is first ascertained that the reagent is of sufficiently
6.1 Aging Tubes, 25× 200mm, heavy wall test tubes made
high purity to permit its use without lessening the accuracy of
of borosilicate glass.
the determination.
6.2 Heating Bath, with liquid heating medium, thermostati-
7.2 Acetone, (Warning—Extremely flammable.)
callycontrolledtomaintainthesampleintheagingtubewithin
1.5°C of 150°C. It must be large enough to hold aging tubes
7.3 Adherent Insolubles Solvent (Trisolvent or TAM), a
immersed in the heating liquid to a depth above the level of
mixture of equal parts by volume of reagent grade toluene
samples in the tubes.The bath and its location shall be such to
(Warning—Flammable.Vapor harmful), acetone (Warning—
enable shielding of the samples from direct light during aging.
see 7.2), and methanol (Warning—Flammable. Vapor harm-
Thevolumeofbathanditsheatrecoveryrateshallbesuchthat
ful. May be fatal or cause blindness if swallowed or inhaled.
the temperature of the medium does not drop more than 5°C
Cannot be made nonpoisonous).
when the maximum number of aging tubes are inserted, and
7.4 Hydrocarbon Solvent, 2,2,4-trimethylpentane (iso-
recovery to 150°C shall not require more than 15min.
octane), 99.75% purity minimum (Warning—see 7.2).
(Warning—Theflashpointoftheliquidheatingmediummust
NOTE 4—Heptane is a satisfactory alternative hydrocarbon solvent.
be at least 180°C. Bath vapors and oil sample vapors shall be
properlyvented.Exposedhotsurfacesontheapparatusandhot
heating medium can cause severe burns.)
The sole source of supply of the apparatus known to the committee at this time
6.3 Bath Thermometer, either glass or digital measuring
is a suitable filter holder available from Millipore Corporation, 80 Ashby Rd.,
Bedford, MA 01730; Catalog No. XX20 047 20. If you are aware of alternative
temperature measuring device, whose accuracy in the 140°C
suppliers, please provide this information to ASTM International Headquarters.
to160°Crangeiscertifiedortraceabletoacertifiedthermom-
Your comments will receive careful consideration at a meeting of the responsible
eter.
technical committee, which you may attend.
The sole source of supply of the apparatus known to the committee at this time
6.4 Membrane Filter Holder,tofit47mmmembranefilters,
is available from UMM Electronics Inc., Photovolt Instruments, 6911 Hillsdale
fitted to a heavy-walled 500mL or 1L vacuum flask.
Court,Indianapolis,IN46250-2062.Ifyouareawareofalternativesuppliers,please
provide this information toASTM International Headquarters.Your comments will
NOTE 1—Several types of membrane filter holders are available. To 1
receive careful consideration at a meeting of the responsible technical committee,
reduce electrostatic hazards, an all metal filter holder equipped with
which you may attend.
Reagent Chemicals, American Chemical Society Specifications, American
Chemical Society, Washington, DC. For suggestions on the testing of reagents not
listed by the American Chemical Society, see Analar Standards for Laboratory
Henry, C. P., “The du Pont F21 149°C (300°F) Accelerated Stability Test,” Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia
Distillate Fuel Stability and Cleanliness, ASTM STP 751, Stavinoha, L. L. and and National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,
Henry, C. P., Eds., ASTM International, 1981, pp. 22–33. MD.
D6468 − 08 (2019)
However,smalldifferencesmaybeseenduetoslightlydifferentsolubility
10. Calibration and Standardization
characteristics. Iso-octane is specified to be in agreement with the
10.1 Turn on the reflection meter and allow at least 30min
hydrocarbon solvent used in other middle distillate stability test methods
forwarm-up.SetthegaintoLOpositionforsearchunit Ywith
such as Test Methods D2274 and D4625.
green filter.
7.5 Filter Paper (Filter Pad), Whatman No. 1, 47mm
10.2 Follow the manufacturer’s instructions to carry out a
diameter, or equivalent.
two point calibration of the reflection meter, using the black
NOTE 5—Filter papers of 42.5mm or 55mm diameter are technically
standard and standard plaque supplied with the search unit.
satisfactory. Filters with a diameter of 47mm permit a small unused
margin for identifying the sample and fit all filtration apparatuses.
NOTE 8—The calibration procedure ensures that the instrument is
working properly. It also indirectly sets a nominal 100% reflectance
8. Sampling setting that is subsequently reset in 10.3.
10.3 Place a newfilter paper on top of a stack of at least ten
8.1 When samples of a fuel batch are obtained to determine
unused Whatman No. 1 filters of the same size. Place the
stability, obtain samples in accordance with Practice D4057.
search unit on the center of the filter, and adjust the meter
Use only epoxy-lined cans or borosilicate glass bottles. Shield
reading to 100%, using the sensitivity control.
clear glass bottles from sunlight to prevent photochemical
reactions.
NOTE 9—Such adjustment, which sets the test method 100% reflec-
tancepoint,altersthereflectancescale;asaresult,thereflectionmeterwill
8.2 When samples are from a fuel or component rundown
no longer read the recited reflectance of the standard plaque.
line, exercise care to ensure that the sampling line and valving
10.4 Place the search unit on the center of the black glass
are thoroughly flushed with current mainstream sample.
standard, and adjust the meter reading to 0%, using the ZERO
8.3 Because stability of some fuels, as determined in this
control. Recheck the 100% adjustment against the new filter
test method, changes over time, the sampling date shall be
paper, and continue adjustment until the meter reads both 0%
recorded; record time and date if sample is from a fuel or
with the black glass standard and 100% with the new filter
component rundown line. Samples should be stored at tem-
pad.
peratures below 5°C. If storage for more than a few days is
expected, oxygen should be removed from the fuel by subsur-
11. Procedure
face purging with a stream of nitrogen; for example, by
11.1 Adjust the heating bath to a temperature of 150°C 6
bubbling nitrogen for 1min⁄L of sample.
1.5°C (see 6.3).
8.3.1 Ifsamplesaretakenoutofcoldstorage,warmthemto
ambient temperature and thoroughly mix prior to aliquot
11.2 Assemble the filter apparatus with a new filter paper.
sampling.
Filteratleast100mLofthefuelsamplethroughthepaper.Use
NOTE 6—If multiple analyses are to be performed on a sample, it is not
the inline vacuum regulator so that the maximum vacuum is
a good practice to warm the whole sample repeatedly for this purpose.
27kPa (200mmHg). Measure two 50mL 6 2mLvolumes of
Onewayofdoingthiswouldbetopouranaliquotofthecoldsampleinto
filtered fuel and decant into each of two aging tubes (see
agraduatedcylinder,cap,allowtowarm,andthendispenseintotheaging
Appendix X3).
tube for analysis. If the cloud point of the fuel is above 5°C, warm to a
temperature 5°C higher than the cloud point before dispensing.
NOTE10—Wherepractical,filterafuelsamplelargerthan100mL.This
...
This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: D6468 − 08 (Reapproved 2013) D6468 − 08 (Reapproved 2019)
Standard Test Method for
High Temperature Stability of Middle Distillate Fuels
This standard is issued under the fixed designation D6468; 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
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 D396, D975, D2880, and D3699. 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 D56, D93, or D3828, is less than
38°C.38 °C. 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.
1.3.1 Exception—The maximum vacuum includes inch-pound units in 6.5 and 11.2.
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 safety, health, and healthenvironmental 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.
2. Referenced Documents
2.1 ASTM Standards:
D56 Test Method for Flash Point by Tag Closed Cup Tester
D93 Test Methods for Flash Point by Pensky-Martens Closed Cup Tester
D396 Specification for Fuel Oils
D975 Specification for Diesel Fuel Oils
D1500 Test Method for ASTM Color of Petroleum Products (ASTM Color Scale)
D2274 Test Method for Oxidation Stability of Distillate Fuel Oil (Accelerated Method)
D2880 Specification for Gas Turbine Fuel Oils
D3699 Specification for Kerosine
D3828 Test Methods for Flash Point by Small Scale Closed Cup Tester
D4057 Practice for Manual Sampling of Petroleum and Petroleum Products
D4625 Test Method for Middle Distillate Fuel Storage Stability at 43 °C (110 °F)
D5452 Test Method for Particulate Contamination in Aviation Fuels by Laboratory Filtration
3. Terminology
3.1 Definitions of Terms Specific to This Standard:
3.1.1 adherent insolubles—material that is produced in the course of stressing distillate fuel and that adheres to the glassware
after fuel has been flushed from the system.
3.1.2 filterable insolubles—material that is produced in the course of stressing distillate fuel and that is capable of being
removed from the fuel by filtration.
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 Stability, Cleanliness and CleanlinessCompatibility of Liquid Fuels.
Current edition approved Oct. 1, 2013May 1, 2019. Published October 2013July 2019. Originally approved in 1999. Last previous edition approved in 20082013 as
D6468 – 08.D6468 – 08 (2013). DOI: 10.1520/D6468-08R13.10.1520/D6468-08R19.
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 Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D6468 − 08 (2019)
3.1.3 inherent stability—the resistance to change when exposed to air, but in the absence of other environmental factors such
as water, reactive metal surfaces, and dirt.
3.1.4 storage stability—the resistance of fuel to formation of degradation products when stored at ambient temperatures.
3.1.5 thermal stability—the resistance of fuel to formation of degradation products when thermally stressed.
4. Summary of Test Method
4.1 Two 50-mL50 mL volumes of filtered middle distillate fuel are aged for 9090 min or 180 min 180 min at 150°C150 °C in
open tubes with air exposure. After aging and cooling, the fuel samples are filtered and the average amount of filterable insolubles
is estimated by measuring the light reflectance of the filter pads. The 100100 % and 0 % extremes of the reflectance rating range
are defined by an unused filter pad and a commercial black standard, respectively.
5. Significance and Use
5.1 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.
5.2 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 D4625, or other lower temperature, long-term tests. When fuel samples are freshly produced, aging for 180
min, 180 min, instead of the traditional 90-min90 min interval, tends to give a result correlating more satisfactorily with the above
methods (see Appendix X2).
5.3 The test method uses a filter paper with a nominal porosity of 11 μm, 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.
6. Apparatus
6.1 Aging Tubes, 25× 200 mm, 200 mm, heavy wall test tubes made of borosilicate glass.
6.2 Heating Bath, with liquid heating medium, thermostatically controlled to maintain the sample in the aging tube within
1.5°C1.5 °C of 150°C.150 °C. It must be large enough to hold aging tubes immersed in the heating liquid to a depth above the level
of samples in the tubes. The bath and its location shall be such to enable shielding of the samples from direct light during aging.
The volume of bath and its heat recovery rate shall be such that the temperature of the medium does not drop more than 5°C5 °C
when the maximum number of aging tubes are inserted, and recovery to 150°C150 °C shall not require more than 15 min. 15 min.
(Warning—WarningThe—The flash point of the liquid heating medium must be at least 180°C.180 °C. Bath vapors and oil sample
vapors shall be properly vented. Exposed hot surfaces on the apparatus and hot heating medium can cause severe burns.)
6.3 Bath Thermometer, either glass or digital measuring temperature measuring device, whose accuracy in the 140140 °C to
160°C160 °C range is certified or traceable to a certified thermometer.
6.4 Membrane Filter Holder, to fit 47-mm47 mm membrane filters, fitted to a heavy-walled 500-mL500 mL or 1-L1 L vacuum
flask.
NOTE 1—Several types of membrane filter holders are available. To reduce electrostatic hazards, an all metal filter holder equipped with grounding
cables is recommended. Such an apparatus and correct grounding practices are described in Test Method D5452. A fritted glass filter holder is less
preferred because of a tendency to become partially clogged during use so that filter pads that do not have uniform deposits are obtained. Glass filter
holders that use a 75-μm (200-mesh)75 μm (200 mesh) screen to support the filter are available; however, since the screen can be an unbonded electrostatic
charge collector, these are not recommended for use with flammable liquids.
6.5 Vacuum Source, that limits the maximum vacuum to 27 kPa (200 mm Hg) 27 kPa (200 mmHg) below atmospheric pressure.
The vacuum should rise to 27 kPa 27 kPa within 1010 s to 15 s 15 s after the sample is added to the filtration funnel.
NOTE 2—Use of reduced vacuum improves retention of particulate on the relatively porous filter media.
Henry, C. P., “The du Pont F21 149°C (300°F)149 °C (300 °F) Accelerated Stability Test,” Distillate Fuel Stability and Cleanliness, ASTM STP 751, Stavinoha, L. L.
and Henry, C. P., Eds., ASTM International, 1981, pp. 22–33.
The sole source of supply of the apparatus known to the committee at this time is a suitable filter holder available from Millipore Corporation, 80 Ashby Rd., Bedford,
MA 01730; Catalog No. XX20 047 20. 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.
D6468 − 08 (2019)
6.6 Reflection meter, Photovolt Model 577 Digital Reflection Meter, complete with search unit Y with a green filter and polished
black glass standard.
NOTE 3—Other reflection meters or search units, or both, can be used, but they are likely to provide only similar (not identical) results. For example,
Photovolt Model 577 digital reflection meter equipped with search unit W usually gives somewhat lower percent reflectance values. Correlation of these
values is discussed in Appendix X1.
7. Reagents and Materials
7.1 Purity of Reagents—Reagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that all
reagents conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society where such
specifications are available. Other grades may be used, provided it is first ascertained that the reagent is of sufficiently high purity
to permit its use without lessening the accuracy of the determination.
7.2 Acetone, (Warning—WarningExtremely—Extremely flammable.)
7.3 Adherent Insolubles Solvent (Trisolvent or TAM), a mixture of equal parts by volume of reagent grade toluene
(Warning—WarningFlammable.—Flammable. Vapor harmful), acetone (Warning—Warningsee—see 7.2), and methanol
(Warning—WarningFlammable.—Flammable. Vapor harmful. May be fatal or cause blindness if swallowed or inhaled. Cannot
be made nonpoisonous).
7.4 Hydrocarbon Solvent, 2,2,4-trimethylpentane (iso-octane), 99.75 % purity minimum (Warning—Warningsee—see 7.2).
NOTE 4—Heptane is a satisfactory alternative hydrocarbon solvent. However, small differences may be seen due to slightly different solubility
characteristics. Iso-octane is specified to be in agreement with the hydrocarbon solvent used in other middle distillate stability test methods such as Test
Methods D2274 and D4625.
7.5 Filter Paper (Filter Pad), Whatman No. 1, 47-mm47 mm diameter, or equivalent.
NOTE 5—Filter papers of 42.542.5 mm or 55-mm55 mm diameter are technically satisfactory. Filters with a diameter of 47 mm 47 mm permit a small
unused margin for identifying the sample and fit all filtration apparatuses.
8. Sampling
8.1 When samples of a fuel batch are obtained to determine stability, obtain samples in accordance with Practice D4057. Use
only epoxy-lined cans or borosilicate glass bottles. Shield clear glass bottles from sunlight to prevent photochemical reactions.
8.2 When samples are from a fuel or component rundown line, exercise care to ensure that the sampling line and valving are
thoroughly flushed with current mainstream sample.
8.3 Because stability of some fuels, as determined in this test method, changes over time, the sampling date shall be recorded;
record time and date if sample is from a fuel or component rundown line. Samples should be stored at temperatures below
5°C.5 °C. If storage for more than a few days is expected, oxygen should be removed from the fuel by subsurface purging with
a stream of nitrogen; for example, by bubbling nitrogen for 11 min min/L ⁄L of sample.
8.3.1 If samples are taken out of cold storage, warm them to ambient temperature and thoroughly mix prior to aliquot sampling.
NOTE 6—If multiple analyses are to be performed on a sample, it is not a good practice to warm the whole sample repeatedly for this purpose. One
way of doing this would be to pour an aliquot of the cold sample into a graduated cylinder, cap, allow to warm, and then dispense into the aging tube
for analysis. If the cloud point of the fuel is above 5ºC,5 °C, warm to a temperature 5ºC5 °C higher than the cloud point before dispensing.
9. Preparation of Apparatus
9.1 Cleaning Aging Tubes—Clean new tubes using adherent insolubles solvent, then with a mildly alkaline or neutral laboratory
detergent, followed by copious rinsing with deionized or distilled water to remove all traces of detergent. Then rinse with acetone
and air dry. Rinse used tubes with trisolvent, dry, then clean as above for new tubes. Visually inspect tubes before use, and reclean
or reject if there is the slightest trace of contamination.
9.1.1 Because of the small sample size and the high surface to volume ratio in this test method, carefully avoid carryover from
past tests or from cleaning agents. There are especially strong effects from traces of copper, strong acids, and strong bases.
NOTE 7—Clean test tubes carefully to avoid carryover from past tests or from cleaning agents. As a result of the small sample size evaluated and the
high surface to volume ratio inherent to the test method, the results obtained can be greatly influenced by the presence of trace contaminants such as
copper, strong acids, or strong bases.
9.2 Cleaning Membrane Filter Holder —Holder—Rinse with trisolvent, then with acetone, and air dry.
The sole source of supply of the apparatus known to the committee at this time is available from UMM Electronics Inc., Photovolt Instruments, 6911 Hillsdale Court,
Indianapolis, IN 46250-2062. 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 techni
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