ASTM D7098-08(2015)
(Test Method)Standard Test Method for Oxidation Stability of Lubricants by Thin-Film Oxygen Uptake (TFOUT) Catalyst B
Standard Test Method for Oxidation Stability of Lubricants by Thin-Film Oxygen Uptake (TFOUT) Catalyst B
SIGNIFICANCE AND USE
5.1 This test method was originally developed to evaluate oxidation stability of lubricating base oils combined with additives chemistries similar to those found in gasoline engine oils and service.2
5.2 This test method is useful for screening formulated oils before engine tests. Within similar additive chemistries and base oil types, the ranking of oils in this test appears to be predictive of ranking in certain engine tests. When oils having different additive chemistries or base oil type are compared, results may or may not reflect results in engine tests. Only gasoline engine oils were used in generating the precision statements in this test method.
SCOPE
1.1 This test method covers the oxidation stability of lubricants by thin-film oxygen uptake (TFOUT) Catalyst B. This test method evaluates the oxidation stability of petroleum products, and it was originally developed as a screening test to indicate whether a given re-refined base stock could be formulated for use as automotive engine oil3 (see Test Method D4742). The test is run at 160 °C in a pressure vessel under oxygen pressure, and the sample contains a metal catalyst package, a fuel catalyst, and water to partially simulate oil conditions in an operating engine. In addition, the test method has since been found broadly useful as an oxidation test of petroleum products.4
1.2 The applicable range of the induction time is from a few minutes up to several hundred minutes or more. However, the range of induction times used for developing the precision statements in this test method was from 40 min to 280 min.
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—Pressure units are provided in psig, and dimensions are provided in inches in Annex A1 and Annex A2, because these are the industry accepted standard and the apparatus is built according to the figures shown.
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 determine the applicability of regulatory limitations prior to use.
General Information
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Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: D7098 − 08 (Reapproved 2015)
Standard Test Method for
Oxidation Stability of Lubricants by Thin-Film Oxygen
1,2
Uptake (TFOUT) Catalyst B
This standard is issued under the fixed designation D7098; 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 1.4 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
1.1 This test method covers the oxidation stability of
responsibility of the user of this standard to establish appro-
lubricants by thin-film oxygen uptake (TFOUT) Catalyst B.
priate safety and health practices and determine the applica-
This test method evaluates the oxidation stability of petroleum
bility of regulatory limitations prior to use.
products, and it was originally developed as a screening test to
indicate whether a given re-refined base stock could be
2. Referenced Documents
formulated for use as automotive engine oil (see Test Method
2.1 ASTM Standards:
D4742). The test is run at 160 °C in a pressure vessel under
A314 Specification for Stainless Steel Billets and Bars for
oxygen pressure, and the sample contains a metal catalyst
Forging
package, a fuel catalyst, and water to partially simulate oil
B211 Specification for Aluminum and Aluminum-Alloy
conditions in an operating engine. In addition, the test method
Rolled or Cold Finished Bar, Rod, and Wire
has since been found broadly useful as an oxidation test of
4 D664 Test Method for Acid Number of Petroleum Products
petroleum products.
by Potentiometric Titration
1.2 The applicable range of the induction time is from a few
D1193 Specification for Reagent Water
minutes up to several hundred minutes or more. However, the
D2272 Test Method for Oxidation Stability of Steam Tur-
range of induction times used for developing the precision
bine Oils by Rotating Pressure Vessel
statements in this test method was from 40 min to 280 min.
D4742 Test Method for Oxidation Stability of Gasoline
Automotive Engine Oils by Thin-Film Oxygen Uptake
1.3 The values stated in SI units are to be regarded as
(TFOUT)
standard. No other units of measurement are included in this
E1 Specification for ASTM Liquid-in-Glass Thermometers
standard.
E144 Practice for Safe Use of Oxygen Combustion Vessels
1.3.1 Exception—Pressure units are provided in psig, and
dimensionsareprovidedininchesinAnnexA1andAnnexA2,
3. Terminology
because these are the industry accepted standard and the
3.1 Definitions of Terms Specific to This Standard:
apparatus is built according to the figures shown.
3.1.1 break point—the precise point of time at which rapid
oxidation of the oil begins.
3.1.2 oxidation induction time—the time until the oil begins
This test method is under the jurisdiction of ASTM Committee D02 on
to oxidize at a relatively rapid rate as indicated by the decrease
Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of
Subcommittee D02.09.0G on Oxidation Testing of Engine Oils.
of oxygen pressure.
Current edition approved Oct. 1, 2015. Published December 2015. Originally
ε1
3.1.3 oxygen uptake—oxygen absorbed by oil as a result of
approved in 2005. Last previous edition approved in 2008 as D7098 – 08 . DOI:
10.1520/D7098-08R15.
oil oxidation.
While Catalyst B can be used for testing oxidation stability of many lubricant
types, the mixture of fuel, nitro-paraffin, and catalyst components used in this test
4. Summary of Test Method
method simulates the Sequence IIIE Engine Test. Test results on several ASTM
reference oils have been found to correlate with Sequence IIIE engine tests in hours
4.1 The test oil is mixed in a glass container with four other
for a 375 % viscosity increase. (See Ku, Chia-Soon, Pei, Patrick T., and Hsu,
liquids used to simulate engine conditions: (1) an oxidized/
Stephen M., “A Modified Thin-Film Oxygen Uptake Test (TFOUT) for the
nitrated fuel component (Annex A3), (2) a mixture of soluble
Evaluation of Lubricant Stability in ASTM Sequence IIIE Test, SAE Technical
Paper Series 902121, Tulsa, OK, Oct. 22-25, 1990.)
Ku, C. S. and Hsu, S. M., “A Thin Film Uptake Test for the Evaluation of
Automotive Lubricants,” Lubrication Engineering, 40, 2, 1984, pp. 75–83. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Selby, Theodore W., “Oxidation Studies with a Modified Thin-Film Oxygen contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Uptake Test”, SAE Technical Paper Series 872127, Toronto, Ontario, Nov. 2-5, Standards volume information, refer to the standard’s Document Summary page on
1987. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D7098 − 08 (2015)
6. Apparatus
6.1 Oxidation Bath and Pressure Vessel—See appropriate
6 7
Annex (Annex A1 or Annex A2 ) for detailed description of
apparatus and accessories for equipment described in this test
method.
NOTE1—Toreducevaporodorswhenopeningpressurevesselafteruse,
a hood may be desirable.
6.2 Precision Pressure Gauge—Use a certified precision
pressure gauge to accurately control the oxygen feed to the
pressure vessel. The gauge shall have a sufficient range to
encompass 0 kPa to 650 kPa (~90 psig) required by the test
method with division 2.0 kPa (~0.5 psig) or better to enable
readings to be made to 2.0 kPa (~0.25 psig).
FIG. 1 Pressure versus Time Diagram of the Oxidation Test 7. Reagents
7.1 Purity of Reagents—Reagent grade chemicals shall be
used in all tests. Unless otherwise indicated, it is intended that
all reagents shall conform to the specifications of the Commit-
metal naphthenates (lead, iron, manganese, and tin naphthen-
teeonAnalyticalReagentsoftheAmericanChemicalSociety.
ates (AnnexA4), (3) a nitro-paraffinic compound, and (4)Type
7.2 Purity of Water—Unless otherwise indicated, references
I reagent water.
to reagent water shall be understood to mean distilled water
meeting requirements of reagent water as defined by Type I of
4.2 The glass container holding the oil mixture is placed in
Specification D1193.
apressurevesselequippedwithapressuresensor.Thepressure
vessel is sealed, charged with oxygen to a pressure of 620 kPa
7.3 Acetone, CH COCH .
3 3
(90 psig), and placed in an oil bath at 160 °C at an angle of 30°
7.4 Air, containing 2000 ppm nitrogen dioxide, NO (com-
from the horizontal. The pressure vessel is rotated axially at a
mercially available compressed gas mixture, certified within
speed of 100 r⁄min forming a thin film of oil within the glass
65 %).
containerresultinginarelativelylargeoil-oxygencontactarea.
7.5 Cyclo-hexane, C H , Practical Grade or other suitable
6 12
4.3 The pressure of the pressure vessel is recorded continu-
hydrocarbon solvent. (Warning—Highly flammable. Skin ir-
ously from the beginning of the test and the test is terminated ritant on repeated contact. Aspiration hazard.)
when a rapid decrease of the pressure vessel pressure is
7.6 Isopropyl Alcohol, CH CH(CH )OH.
3 3
observed (Point B, Fig. 1). The period of time that elapses
7.7 Oxygen, 99.8 %.
between the time when the pressure vessel is placed in the oil
bath and the time at which the pressure begins to decrease
8. Materials
rapidly is called the oxidation induction time and is used as a
8.1 TFOUT Catalyst B Package:
measure of the relative oil oxidation stability.
5. Significance and Use
The sole source of supply of the apparatus known to the committee at this time
5.1 This test method was originally developed to evaluate
is Koehler Instrument Co., Inc., 1595 Sycamore Ave., Bohemia, NY11716 and
oxidation stability of lubricating base oils combined with Stanhope-Seta, London St., Chertsey, Surrey, KT16 8AP, U.K. If you are aware of
alternative suppliers, please provide this information to ASTM International
additives chemistries similar to those found in gasoline engine
Headquarters.Your comments will receive careful consideration at a meeting of the
oils and service. 1
responsible technical committee, which you may attend.
The sole source of supply of the apparatus known to the committee at this time
5.2 This test method is useful for screening formulated oils
is Tannas Co., 4800 James Savage Rd., Midland, MI 48642. If you are aware of
alternative suppliers, please provide this information to ASTM International
before engine tests. Within similar additive chemistries and
Headquarters.Your comments will receive careful consideration at a meeting of the
base oil types, the ranking of oils in this test appears to be
responsible technical committee, which you may attend.
predictive of ranking in certain engine tests. When oils having 8
Reagent Chemicals, American Chemical Society Specifications, American
Chemical Society, Washington, DC. For Suggestions on the testing of reagents not
different additive chemistries or base oil type are compared,
listed by the American Chemical Society, see Annual Standards for Laboratory
results may or may not reflect results in engine tests. Only
Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia
gasoline engine oils were used in generating the precision
and National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,
statements in this test method. MD.
D7098 − 08 (2015)
relatively low pressures involved in running this test method.
8.1.1 Fuel Component—The fuel component is a nitrated
gasoline fraction or organic equivalent. This component may
9.5 Cleaning of Catalyst Syringes—Use individual catalyst
be prepared in accordance with the procedures described in
syringes for each catalyst component. Thoroughly clean and
Annex A3.
dry syringes prior to each use. (See Annex A5 for recom-
8.1.2 Soluble Metal Catalyst Mixture—This catalyst is a
mended procedure.)
mixture of soluble metal catalysts (lead, iron, manganese, and
tin). The catalyst may be prepared according to the procedures
10. Procedure
described in Annex A4.
10.1 Weighing and Mixing Sample and Catalyst Compo-
8.1.2.1 Other oxidation stability test methods have demon-
nents:
strated that soluble metal catalyst supplies may be inconsistent
and have significant effects on the test results. Thus, for test 10.1.1 Place the clean glass sample container onto the
comparisons, the same source and same batch of metal precision balance and tare.
naphthenates shall be used.
10.1.2 Weigh 1.500 g 6 0.001 g of oil sample into the
container and tare.
NOTE 2—It is good research practice to use the same batches of catalyst
components when closely comparing engine oils. 10.1.3 Add 0.045 g 6 0.001 g of the soluble metal catalyst
NOTE 3—Slow, steady reactivity of some of the catalyst chemicals can
mixture into the glass sample container and tare.
beaproblem.Suchproblemscanbereducedbystoringtheclosedcatalyst
10.1.4 Add 0.030 g 6 0.001 g each of the fuel component,
vials in a refrigerator at approximately 5 °C. The catalyst chemicals
nitro-paraffin and reagent water to the glass sample container
remain effective up to six months after the septum is punctured, if they are
stored as noted above.
and tare each time. It is easiest to add the distilled water last
and place on top of the oil sample.
8.1.3 Nitro-paraffın—This compound is made up of a nitri-
alkane blend. 10.1.5 Just prior to inserting the glass sample container into
the pressure vessel, thoroughly mix the catalyst components
NOTE 4—Suitably prepared catalyst packages may be purchased from
7 within the sample container by hand-rotation (approximately
Tannas Co.
five rotations) and proceed immediately to 10.2. Delay may
8.2 Varnish and Deposit Remover, water-soluble varnish
result in variation of results.
remover or other engine varnish/deposit removers.
10.2 Pressure Vessel Assembly and Charging—Immediately
8.3 Silicone Stopcock Grease.
and rapidly assemble and charge the pressure vessel in accor-
dance with apparatus type (see A1.2 or A2.7).
9. Preparation of Apparatus
NOTE 8—Avoid releasing the oxygen too rapidly by decreasing the
9.1 Glass Sample Container—A clean glass sample con-
pressure to atmospheric in no less than 1 min to avoid possible foaming
tainer is important for obtaining repeatable results. Thorough
and overflow of the sample from the glass sample container.
cleaning can be accomplished by (a) rinsing with cyclo-hexane
10.3 Oxidation—Before starting the test, bring the heating
or other suitable hydrocarbon solvent, (b) soaking in concen-
bath to the test temperature at 160 °C and insert the pressure
trated solution of a water-soluble varnish remover, (c) thor-
vessel(s)inaccordancewithapparatustype(seeA1.3orA2.8).
oughly rinsing with water, (d) rinsing with acetone, (e) and
10.3.1 Allow the bath temperature to level out at the test
permitting to dry.
temperature, which must occur within 15 min after insertion of
NOTE 5—A segmented glass reaction dish has been found suitable to
prevent premature mixing of the catalyst components (see Fig. A2.4) thepressurevessel.Maintainingthetesttemperaturewithinthe
specified limits of 160 °C 6 0.3 °C during the entire test run is
9.2 Cleaning of Pressure Vessel—Fill with concentrated
themostimportantsinglefactorensuringbothrepeatabilityand
solution of a water-soluble varnish remover and soak for
reproducibility of test results. If the test temperature cannot be
suitable time, rinse with water, rinse with acetone, and permit
maintained as specified, the test results shall not be considered
to dry.
valid.
9.3 Cleaning of Pressure Vessel Stem—Periodically
disassemble, inspect, and clean the pressure vessel stem. Rinse
NOTE 9—The time for the bath to reach the operating temperature after
insertion of the pressure vessel may differ for different apparatus assem-
theinsideofthestemwithisopropylalcoholandblowdrywith
blies and shall be observed for each unit (a unit may carry one, two, three,
oil free compressed air. For users of apparatus described in
orfourpressurevessels).Theobjectiveistofindasetofconditions,which
Annex A1, periodically insert a dry pipe cleaner into the
does not permit a drop of more than 2 °C after insertion of the pressure
transducer line opening for removal of potential residue
vessel(s) and allows the pressure vessel pressure to reach plateau within
buildup. 15 min.
NOTE 6—Replace O-rings when reassembling the pressure transducers.
10.4 Keep the pressure vessel completely submerged and
9.4 Periodicallypressuretestthepressurevesselsat690 kPa
maintain continuous and uniform rotation throughout the test.
(~100 psi) with air
...
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.
´1
Designation: D7098 − 08 D7098 − 08 (Reapproved 2015)
Standard Test Method for
Oxidation Stability of Lubricants by Thin-Film Oxygen
1,2
Uptake (TFOUT) Catalyst B
This standard is issued under the fixed designation D7098; 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—Updated units statement in 1.3 and improved figure quality editorially in November 2009.
1. Scope*Scope
1.1 This test method covers the oxidation stability of lubricants by thin-film oxygen uptake (TFOUT) Catalyst B. This test
method evaluates the oxidation stability of petroleum products, and it was originally developed as a screening test to indicate
whether a given re-refined base stock could be formulated for use as automotive engine oil (see Test Method D4742). The test
is run at 160°C160 °C in a pressure vessel under oxygen pressure, and the sample contains a metal catalyst package, a fuel catalyst,
and water to partially simulate oil conditions in an operating engine. In addition, the test method has since been found broadly
useful as an oxidation test of petroleum products.
1.2 The applicable range of the induction time is from a few minutes up to several hundred minutes or more. However, the range
of induction times used for developing the precision statements in this test method was from 4040 min to 280 min.
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—Pressure units are provided in psig, and dimensions are provided in inches in Annex A1 and Annex A2,
because these are the industry accepted standard and the apparatus is built according to the figures shown.
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 determine the applicability of regulatory
limitations prior to use.
2. Referenced Documents
2.1 ASTM Standards:
A314 Specification for Stainless Steel Billets and Bars for Forging
B211 Specification for Aluminum and Aluminum-Alloy Rolled or Cold Finished Bar, Rod, and Wire
D664 Test Method for Acid Number of Petroleum Products by Potentiometric Titration
D1193 Specification for Reagent Water
D2272 Test Method for Oxidation Stability of Steam Turbine Oils by Rotating Pressure Vessel
D4742 Test Method for Oxidation Stability of Gasoline Automotive Engine Oils by Thin-Film Oxygen Uptake (TFOUT)
E1 Specification for ASTM Liquid-in-Glass Thermometers
E144 Practice for Safe Use of Oxygen Combustion Vessels
3. Terminology
3.1 Definitions of Terms Specific to This Standard:
3.1.1 break point—the precise point of time at which rapid oxidation of the oil begins.
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
D02.09.0G on Oxidation Testing of Engine Oils.
Current edition approved Oct. 15, 2008Oct. 1, 2015. Published November 2008December 2015. Originally approved in 2005. Last previous edition approved in 20062008
ε1
as D7098D7098 – 08–06 . DOI: 10.1520/D7098-08E01.10.1520/D7098-08R15.
While Catalyst B can be used for testing oxidation stability of many lubricant types, the mixture of fuel, nitro-paraffin, and catalyst components used in this test method
simulates the Sequence IIIE Engine Test. Test results on several ASTM reference oils have been found to correlate with Sequence IIIE engine tests in hours for a 375 %
viscosity increase. (See Ku, Chia-Soon, Pei, Patrick T., and Hsu, Stephen M., “A Modified Thin-Film Oxygen Uptake Test (TFOUT) for the Evaluation of Lubricant Stability
in ASTM Sequence IIIE Test, SAE Technical Paper Series 902121, Tulsa, OK, Oct. 22-25, 1990.)
Ku, C. S. and Hsu, S. M., “A Thin Film Uptake Test for the Evaluation of Automotive Lubricants,” Lubrication Engineering, 40, 2, 1984, pp. 75–83.
Selby, Theodore W., “Oxidation Studies with a Modified Thin-Film Oxygen Uptake Test”, SAE Technical Paper Series 872127, Toronto, Ontario, Nov. 2-5, 1987.
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.
*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
D7098 − 08 (2015)
FIG. 1 Pressure versus Time Diagram of the Oxidation Test
3.1.2 oxidation induction time—the time until the oil begins to oxidize at a relatively rapid rate as indicated by the decrease of
oxygen pressure.
3.1.3 oxygen uptake—oxygen absorbed by oil as a result of oil oxidation.
4. Summary of Test Method
4.1 The test oil is mixed in a glass container with four other liquids used to simulate engine conditions: (1) an oxidized/nitrated
fuel component (Annex A3), (2) a mixture of soluble metal naphthenates (lead, iron, manganese, and tin naphthenates (Annex A4),
(3) a nitro-paraffinic compound, and (4) Type I reagent water.
4.2 The glass container holding the oil mixture is placed in a pressure vessel equipped with a pressure sensor. The pressure
vessel is sealed, charged with oxygen to a pressure of 620 kPa (90 psig), 620 kPa (90 psig), and placed in an oil bath at
160°C160 °C at an angle of 30° from the horizontal. The pressure vessel is rotated axially at a speed of 100100 r ⁄ r/min min
forming a thin film of oil within the glass container resulting in a relatively large oil-oxygen contact area.
4.3 The pressure of the pressure vessel is recorded continuously from the beginning of the test and the test is terminated when
a rapid decrease of the pressure vessel pressure is observed (Point B, Fig. 1). The period of time that elapses between the time when
the pressure vessel is placed in the oil bath and the time at which the pressure begins to decrease rapidly is called the oxidation
induction time and is used as a measure of the relative oil oxidation stability.
5. Significance and Use
5.1 This test method was originally developed to evaluate oxidation stability of lubricating base oils combined with additives
chemistries similar to those found in gasoline engine oils and service.
5.2 This test method is useful for screening formulated oils before engine tests. Within similar additive chemistries and base
oil types, the ranking of oils in this test appears to be predictive of ranking in certain engine tests. When oils having different
additive chemistries or base oil type are compared, results may or may not reflect results in engine tests. Only gasoline engine oils
were used in generating the precision statements in this test method.
6. Apparatus
6 7
6.1 Oxidation Bath and Pressure Vessel—See appropriate Annex (Annex A1 or Annex A2 ) for detailed description of
apparatus and accessories for equipment described in this test method.
NOTE 1—To reduce vapor odors when opening pressure vessel after use, a hood may be desirable.
6.2 Precision Pressure Gauge—Use a certified precision pressure gauge to accurately control the oxygen feed to the pressure
vessel. The gauge shall have a sufficient range to encompass 0 to 650 kPa (~90 psig) 0 kPa to 650 kPa (~90 psig) required by the
test method with division 2.0 kPa (~0.5 psig) 2.0 kPa (~0.5 psig) or better to enable readings to be made to 2.0 kPa (~0.25
psig).2.0 kPa (~0.25 psig).
The sole source of supply of the apparatus known to the committee at this time is Koehler Instrument Co., Inc., 1595 Sycamore Ave., Bohemia, NY11716 and
Stanhope-Seta, London St., Chertsey, Surrey, KT16 8AP, U.K. 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.
The sole source of supply of the apparatus known to the committee at this time is Tannas Co., 4800 James Savage Rd., Midland, MI 48642. 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.
D7098 − 08 (2015)
7. Reagents
7.1 Purity of Reagents—Reagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that all
reagents shall conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society.
7.2 Purity of Water—Unless otherwise indicated, references to reagent water shall be understood to mean distilled water meeting
requirements of reagent water as defined by Type I of Specification D1193.
7.3 Acetone, CH COCH .
3 3
7.4 Air, containing 2000 ppm 2000 ppm nitrogen dioxide, NO (commercially available compressed gas mixture, certified
within 65 %).
7.5 Cyclo-hexane, C H , Practical Grade or other suitable hydrocarbon solvent. (Warning—Highly flammable. Skin irritant
6 12
on repeated contact. Aspiration hazard.)
7.6 Isopropyl Alcohol, CH CH(CH )OH.
3 3
7.7 Oxygen, 99.8 %.
8. Materials
8.1 TFOUT Catalyst B Package:
8.1.1 Fuel Component—The fuel component is a nitrated gasoline fraction or organic equivalent. This component may be
prepared in accordance with the procedures described in Annex A3.
8.1.2 Soluble Metal Catalyst Mixture—This catalyst is a mixture of soluble metal catalysts (lead, iron, manganese, and tin). The
catalyst may be prepared according to the procedures described in Annex A4.
8.1.2.1 Other oxidation stability test methods have demonstrated that soluble metal catalyst supplies may be inconsistent and
have significant effects on the test results. Thus, for test comparisons, the same source and same batch of metal naphthenates shall
be used.
NOTE 2—It is good research practice to use the same batches of catalyst components when closely comparing engine oils.
NOTE 3—Slow, steady reactivity of some of the catalyst chemicals can be a problem. Such problems can be reduced by storing the closed catalyst vials
in a refrigerator at approximately 5°C.5 °C. The catalyst chemicals remain effective up to six months after the septum is punctured, if they are stored as
noted above.
8.1.3 Nitro-paraffın—This compound is made up of a nitrialkane blend.
NOTE 4—Suitably prepared catalyst packages may be purchased from Tannas Co.
8.2 Varnish and Deposit Remover, water-soluble varnish remover or other engine varnish/deposit removers.
8.3 Silicone Stopcock Grease.
9. Preparation of Apparatus
9.1 Glass Sample Container—A clean glass sample container is important for obtaining repeatable results. Thorough cleaning
can be accomplished by (a) rinsing with cyclo-hexane or other suitable hydrocarbon solvent, (b) soaking in concentrated solution
of a water-soluble varnish remover, (c) thoroughly rinsing with water, (d) rinsing with acetone, (e) and permitting to dry.
NOTE 5—A segmented glass reaction dish has been found suitable to prevent premature mixing of the catalyst components (see Fig. A2.4)
9.2 Cleaning of Pressure Vessel—Fill with concentrated solution of a water-soluble varnish remover and soak for suitable time,
rinse with water, rinse with acetone, and permit to dry.
9.3 Cleaning of Pressure Vessel Stem—Periodically disassemble, inspect, and clean the pressure vessel stem. Rinse the inside
of the stem with isopropyl alcohol and blow dry with oil free compressed air. For users of apparatus described in Annex A1,
periodically insert a dry pipe cleaner into the transducer line opening for removal of potential residue buildup.
NOTE 6—Replace O-rings when reassembling the pressure transducers.
9.4 Periodically pressure test the pressure vessels at 690 kPa (~100 psi) 690 kPa (~100 psi) with air or oxygen. If the pressure
drops more than 0.690 kPa (~0.1 psi) 0.690 kPa (~0.1 psi) on the pressure gauge within 60 s, 60 s, replace the O-ring seals and
inspect the valve seals according to manufacturer’s directions. If the problem continues, contact the specific equipment
manufacturer.
NOTE 7—Previous versions of this test method have called for hydrostatic testing of the pressure vessel. This was found unnecessary at the relatively
low pressures involved in running this test method.
9.5 Cleaning of Catalyst Syringes—Use individual catalyst syringes for each catalyst component. Thoroughly clean and dry
syringes prior to each use. (See Annex A5 for recommended procedure.)
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 Annual Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia and National
Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville, MD.
D7098 − 08 (2015)
10. Procedure
10.1 Weighing and Mixing Sample and Catalyst Components:
10.1.1 Place the clean glass sample container onto the precision balance and tare.
10.1.2 Weigh 1.5001.500 g 6 0.001 g 0.001 g of oil sample into the container and tare.
10.1.3 Add 0.0450.045 g 6 0.001 g 0.001 g of the soluble metal catalyst mixture into the glass sample container and tare.
10.1.4 Add 0.0300.030 g 6 0.001 g 0.001 g each of the fuel component, nitro-paraffin and reagent water to the glass sample
container and tare each time. It is easiest to add the distilled water last and place on top of the oil sample.
10.1.5 Just prior to inserting the glass sample container into the pressure vessel, thoroughly mix the catalyst components within
the sample container by hand-rotation (approximately five rotations) and proceed immediately to 10.2. Delay may result in
variation of results.
10.2 Pressure Vessel Assembly and Charging—Immediately and rapidly assemble and charge the pressure vessel in accordance
with apparatus type (see A1.2 or A2.7).
NOTE 8—Avoid releasing the oxygen too rapidly by decreasing the pressure to atmospheric in no less than 1 min to avoid po
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