ASTM D873-22

Standard Test Method for Oxidation Stability of Aviation Fuels (Potential Residue Method)

SIGNIFICANCE AND USE
5.1 The results (of these tests) can be used to indicate storage stability of these fuels. The tendency of fuels to form gum and deposits in these tests has not been correlated with field performance (and can vary markedly) with the formation of gum and deposits under different storage conditions.
SCOPE
1.1 This test method3 covers the determination of the tendency of aviation reciprocating, turbine, and jet engine fuels to form gum and deposits under accelerated aging conditions. (Warning—This test method is not intended for determining the stability of fuel components, particularly those with a high percentage of low boiling unsaturated compounds, as these may cause explosive conditions within the apparatus.)
Note 1: For the measurement of the oxidation stability (induction period) of motor gasoline, refer to Test Method D525.  
1.2 The accepted SI unit of pressure is the kilo pascal (kPa); the accepted SI unit of temperature is °C.  
1.3 WARNING—Mercury has been designated by many regulatory agencies as a hazardous substance that can cause serious medical issues. Mercury, or its vapor, has been demonstrated to be hazardous to health and corrosive to materials. Use caution when handling mercury and mercury-containing products. See the applicable product Safety Data Sheet (SDS) for additional information. The potential exists that selling mercury or mercury-containing products, or both, is prohibited by local or national law. Users must determine legality of sales in their location.  
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

• Status: Published
• Publication Date: 30-Jun-2022
• ICS: 75.160.20 - Liquid fuels
• Technical Committee: D02 - Petroleum Products, Liquid Fuels, and Lubricants
• Drafting Committee: D02.14 - Stability, Cleanliness and Compatibility of Liquid Fuels

Relations

• Refers: ASTM E1-13 - Standard Specification for ASTM Liquid-in-Glass Thermometers
• Effective Date: 01-May-2013
• Refers: ASTM D525-12 - Standard Test Method for Oxidation Stability of Gasoline (Induction Period Method)
• Effective Date: 15-Apr-2012
• Refers: ASTM D4057-06(2011) - Standard Practice for Manual Sampling of Petroleum and Petroleum Products
• Effective Date: 01-Jun-2011
• Refers: ASTM D381-09 - Standard Test Method for Gum Content in Fuels by Jet Evaporation
• Effective Date: 15-Apr-2009
• Refers: ASTM E1-07 - Standard Specification for ASTM Liquid-in-Glass Thermometers
• Effective Date: 01-Nov-2007
• Refers: ASTM D5452-06 - Standard Test Method for Particulate Contamination in Aviation Fuels by Laboratory Filtration
• Effective Date: 01-Dec-2006
• Refers: ASTM D5452-05 - Standard Test Method for Particulate Contamination in Aviation Fuels by Laboratory Filtration
• Effective Date: 01-Dec-2005
• Refers: ASTM E1-05 - Standard Specification for ASTM Liquid-in-Glass Thermometers
• Effective Date: 01-Nov-2005
• Refers: ASTM D525-05 - Standard Test Method for Oxidation Stability of Gasoline (Induction Period Method)
• Effective Date: 01-Apr-2005
• Refers: ASTM D381-04 - Standard Test Method for Gum Content in Fuels by Jet Evaporation
• Effective Date: 01-Nov-2004
• Refers: ASTM D381-04e1 - Standard Test Method for Gum Content in Fuels by Jet Evaporation
• Effective Date: 01-Nov-2004
• Refers: ASTM E1-03a - Standard Specification for ASTM Liquid-in-Glass Thermometers
• Effective Date: 01-Nov-2003
• Refers: ASTM D381-03 - Standard Test Method for Gum Content in Fuels by Jet Evaporation
• Effective Date: 10-Jul-2003
• Refers: ASTM E1-03 - Standard Specification for ASTM Thermometers
• Effective Date: 10-May-2003
• Refers: ASTM D381-01 - Standard Test Method for Gum Content in Fuels by Jet Evaporation
• Effective Date: 10-Nov-2001

Overview

ASTM D873-22: Standard Test Method for Oxidation Stability of Aviation Fuels (Potential Residue Method) is a crucial standard developed by ASTM International for evaluating the oxidation stability of aviation fuels. This test method assesses the tendency of reciprocating, turbine, and jet engine fuels to form gum and deposits under accelerated aging conditions, providing an indication of fuel storage stability. The outcomes from this test help fuel manufacturers, quality control laboratories, and aerospace stakeholders ensure that aviation fuels maintain performance integrity during storage and handling.

Key Topics

• Scope of Application

  • Applies to aviation fuels intended for reciprocating engines, turbines, and jet engines.
  • Not suitable for evaluating the stability of fuel components with a high percentage of low boiling unsaturated compounds due to potential explosive conditions.

• Test Principle

  • The fuel sample is exposed to oxygen in a pressure vessel at an elevated temperature.
  • Following oxidation, the quantities of soluble gum, insoluble gum, and precipitate formed are determined.
  • The procedure simulates fuel aging to provide information about possible residue formation during storage.

• Measurement Units

  • Pressure is measured in kilopascals (kPa).
  • Temperature is expressed in degrees Celsius (°C).

• Safety and Environmental Cautions

  • Mercury is referenced as a hazardous substance; users must follow safety, health, and environmental best practices and check regulatory requirements regarding mercury-containing apparatus.

• Data Interpretation

  • Results are reported in terms of gum content and total potential residue, essential for quality assessment and compliance.

Applications

• Fuel Production and Refinery Quality Control

  • Enables producers to verify and optimize the oxidation stability of aviation fuels before distribution.

• Aviation Fuel Storage

  • Assists storage facilities and terminal operators in assessing how aviation fuels may degrade over time and in identifying preventive measures for resin/gum formation.

• Aerospace Regulatory Compliance

  • Supports aircraft operators and regulators in maintaining fuel quality, ensuring safety and regulatory compliance for flight operations.

• Research and Development

  • Facilitates the development of aviation fuels with improved storage stability by evaluating candidate formulations under standardized conditions.

• International Acceptance

  • Developed in collaboration with the Energy Institute (London), making it widely recognized for global use in the aviation sector.

Related Standards

• ASTM D381 - Test Method for Gum Content in Fuels by Jet Evaporation. Used for routine gum content analysis in fuels.
• ASTM D525 - Test Method for Oxidation Stability of Gasoline (Induction Period Method). Referenced for motor gasoline oxidation stability.
• ASTM D4057 - Practice for Manual Sampling of Petroleum and Petroleum Products. Guides sampling techniques for accurate fuel testing.
• ASTM D5452 - Test Method for Particulate Contamination in Aviation Fuels by Laboratory Filtration. Addresses particulate contamination assessment.

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Keywords: ASTM D873-22, oxidation stability, aviation fuels, potential residue, gum content, storage stability, jet fuel, turbine fuel, reciprocating engine fuel, fuel quality, ASTM standards, aviation fuel testing.

Practical Value: ASTM D873-22 provides essential guidelines for consistently measuring oxidation stability, helping the aviation industry manage fuel storage risks and ensuring compliance with international quality requirements.

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.
Designation: D873 − 22 British Standard 4456
Designation: 138/99
Standard Test Method for
Oxidation Stability of Aviation Fuels (Potential Residue
1,2
Method)
This standard is issued under the fixed designation D873; 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.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope* priate safety, health, and environmental practices and deter-
3 mine the applicability of regulatory limitations prior to use.
1.1 This test method covers the determination of the
1.5 This international standard was developed in accor-
tendencyofaviationreciprocating,turbine,andjetenginefuels
dance with internationally recognized principles on standard-
to form gum and deposits under accelerated aging conditions.
ization established in the Decision on Principles for the
(Warning—This test method is not intended for determining
Development of International Standards, Guides and Recom-
the stability of fuel components, particularly those with a high
mendations issued by the World Trade Organization Technical
percentage of low boiling unsaturated compounds, as these
Barriers to Trade (TBT) Committee.
may cause explosive conditions within the apparatus.)
NOTE 1—For the measurement of the oxidation stability (induction 2. Referenced Documents
period) of motor gasoline, refer to Test Method D525.
2.1 ASTM Standards:
1.2 The accepted SI unit of pressure is the kilo pascal (kPa);
D381 Test Method for Gum Content in Fuels by Jet Evapo-
the accepted SI unit of temperature is °C.
ration
D525 Test Method for Oxidation Stability of Gasoline (In-
1.3 WARNING—Mercury has been designated by many
duction Period Method)
regulatory agencies as a hazardous substance that can cause
D4057 Practice for Manual Sampling of Petroleum and
serious medical issues. Mercury, or its vapor, has been dem-
Petroleum Products
onstrated to be hazardous to health and corrosive to materials.
D5452 Test Method for Particulate Contamination in Avia-
Use caution when handling mercury and mercury-containing
tion Fuels by Laboratory Filtration
products. See the applicable product Safety Data Sheet (SDS)
for additional information. The potential exists that selling E1 Specification for ASTM Liquid-in-Glass Thermometers
mercury or mercury-containing products, or both, is prohibited
3. Terminology
by local or national law. Users must determine legality of sales
in their location.
3.1 The following definitions of terms are all expressed in
terms of milligrams per 100 mL of sample, after “X” hours
1.4 This standard does not purport to address all of the
aging, “X” being the accelerated aging (oxidation) period at
safety concerns, if any, associated with its use. It is the
100 °C.
responsibility of the user of this standard to establish appro-
3.2 Definitions of Terms Specific to This Standard:
3.2.1 insoluble gum, n—deposit adhering to the glass
sample container after removal of the aged fuel, precipitate,
This test method is under the jurisdiction of ASTM International Committee
D02 on Petroleum Products, Liquid Fuels, and Lubricants and is the direct
and soluble gum.
responsibility of ASTM Subcommittee D02.14 on Stability, Cleanliness and
3.2.1.1 Discussion—Insoluble gum is obtained by measur-
Compatibility of Liquid Fuels. The technically equivalent standard as referenced is
ing the increase in mass of the glass sample container.
under the jurisdiction of the Energy Institute Subcommittee SC-B-8.
Current edition approved July 1, 2022. Published August 2022. Originally
3.2.2 potential gum, n—sum of the soluble and insoluble
approved in 1946. Last previous edition approved in 2018 as D873 – 12 (2018).
gum.
DOI: 10.1520/D0873-22.
This test method has been developed through the cooperative effort between
ASTM and the Energy Institute, London.ASTM and IPstandards were approved by
ASTMandEItechnicalcommitteesasbeingtechnicallyequivalentbutthatdoesnot For referenced ASTM standards, visit the ASTM website, www.astm.org, or
imply both standards are identical. contact ASTM Customer Service at [e-mail]. 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.
*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
D873 − 22
3.2.3 precipitate,n—sedimentandsuspendedmaterialinthe tainingitatitsboilingpoint,whichmustbebetween99.5 °Cto
aged fuel, obtained by filtering the aged fuel and washings 100.5 °C. If a liquid medium other than water is used, an
from the glass sample container. appropriate mechanical stirrer/mixer shall be used to maintain
uniformity of the liquid bath at 100 °C 6 0.2 °C. A non
3.2.4 soluble gum, n—deterioration products present at the
self-resettable device shall be fitted on all new baths to ensure
end of a specific aging period. These deterioration products
that the heater is switched off if the liquid bath falls below a
exist in solution in the aged fuel and as the toluene-acetone
safe level. Users of older baths without this device are strongly
soluble portion of the deposit on the glass sample container.
urged to have the equipment retrofitted to ensure safe opera-
3.2.4.1 Discussion—The soluble gum is obtained as a non-
tion.
volatile residue by evaporating the aged fuel and the toluene-
acetone washings from the glass sample container.
NOTE 4—Electric heating blocks are known to be used. These blocks
can have heating capacities, heating rates, and heat transfer characteristics
3.2.5 total potential residue, n—sum of the potential gum
that differ from those of a liquid bath. An electric heating block may be
and the precipitate.
used in place of the liquid bath as long as the sample heating rate and
sample temperature are demonstrated to be equivalent to that of the liquid
4. Summary of Test Method
bath.
4.1 The fuel is oxidized under prescribed conditions in a
6.7 Cooling Vessel—A desiccator or other type of tightly
pressure vessel filled with oxygen. The amounts of soluble
covered vessel for cooling the beakers before weighing. The
gum, insoluble gum, and precipitate formed are weighed.
use of a drying agent is not recommended.
(Warning—In addition to other precautions, to provide pro-
tection against the possibility of explosive rupture of the
7. Reagents and Materials
pressure vessel, the pressure vessel should be operated behind
7.1 Gum Solvent—A mixture of equal volumes of toluene
an appropriate safety shield.)
and acetone.
7.2 Oxygen, commercially available extra dry oxygen of not
5. Significance and Use
less than 99.6 % purity.
5.1 The results (of these tests) can be used to indicate
storage stability of these fuels. The tendency of fuels to form
8. Sampling
gum and deposits in these tests has not been correlated with
8.1 Sample in accordance with the procedure for oxidation
field performance (and can vary markedly) with the formation
stability, as described in Practice D4057.
of gum and deposits under different storage conditions.
9. Preparation of Apparatus
6. Apparatus
9.1 Thoroughly clean a glass sample container to remove
6.1 Oxidation Pressure Vessel, Burst Disc Assembly, Glass
traces of any adhering material. Immerse the container and its
Sample Container and Cover, Accessories and Pressure Gage,
cover in a mildly alkaline or neutral pH laboratory detergent
as described in the Annex to Test Method D525.(Warning—
cleaning solution. The type of detergent and conditions for its
Provision shall be made to safely vent any expelled gases or
use need to be established in each laboratory. The criterion for
flames away from the operator, other personnel, or flammable
satisfactory cleaning shall be a matching of the quality of that
materials as a safety precaution if the burst-disc ruptures.)
obtained with chromic acid cleaning solutions (or some other
NOTE2—PressurevesselsconformingtoTestMethodD525–80arealso
equivalently strong oxidizing non-chromium containing acid
suitable, but the specified burst-disc shall be attached. The burst disc
cleaning solutions) on used sample containers and covers
assembly shall be mechanically designed to ensure that it cannot be
(fresh chromic acid, 6 h soaking period, rinsing with distilled
incorrectly fitted.
water and drying). For this comparison, visual appearance and
6.2 Thermometer, having a range as shown below and
mass loss on heating the glassware under test conditions may
conforming to the requirements as prescribed in Specification
be used. Detergent cleaning avoids the potential hazards and
E1, or specifications for IP thermometers:
inconveniences related to the handling of highly corrosive and
Thermometer Range Thermometer Number
strongly oxidizing acid solutions; this procedure remains the
ASTM IP
95 °C to 103 °C 22C 24C reference cleaning practice and, as such, may function as an
alternate to the preferred procedure, cleaning with detergent
NOTE 3—Other temperature sensing devices that cover the temperature
solutions. Remove from the cleaning solution by means of
range of interest, such as thermocouples or platinum resistance
thermometers, that can provide equivalent or better accuracy and
corrosion-resistant steel forceps and handle only with forceps
precision, may be used in place of the thermometers specified in 6.2.
thereafter. Wash thoroughly first with tap water and then with
6.3 Drying Oven, air oven maintained at 100 °C to 150 °C.
deionized or distilled water, and dry in an oven at 100 °C to
150 °C for 1 h. Cool the sample containers and covers for at
6.4 Forceps, corrosion-resistant, steel.
least 2 h in the cooling vessel in the vicinity of the balance.
6.5 Filtering Crucible, sintered-glass, fine porosity.
Weigh to the nearest 0.1 mg, and record mass.
6.6 Oxidation Bath, as described in the Annex to Test 9.1.1 Experience indicates that the amount of insoluble gum
Method D525.
...

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: D873 − 12 (Reapproved 2018) D873 − 22 British Standard 4456
Designation: 138/99
Standard Test Method for
Oxidation Stability of Aviation Fuels (Potential Residue
1,2
Method)
This standard is issued under the fixed designation D873; 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.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope Scope*
1.1 This test method covers the determination of the tendency of aviation reciprocating, turbine, and jet engine fuels to form gum
and deposits under accelerated aging conditions. (Warning—This test method is not intended for determining the stability of fuel
components, particularly those with a high percentage of low boiling unsaturated compounds, as these may cause explosive
conditions within the apparatus.)
NOTE 1—For the measurement of the oxidation stability (induction period) of motor gasoline, refer to Test Method D525.
1.2 The accepted SI unit of pressure is the kilo pascal (kPa); the accepted SI unit of temperature is °C.
1.3 WARNING—Mercury has been designated by many regulatory agencies as a hazardous materialsubstance that can cause
central nervous system, kidney and liver damage. serious medical issues. Mercury, or its vapor, may has been demonstrated to be
hazardous to health and corrosive to materials. Caution should be taken Use caution when handling mercury and mercury
containing mercury-containing products. See the applicable product Material Safety Data Sheet (MSDS) for details and EPA’s
website—http://www.epa.gov/mercury/faq.htm—for additional information. Users should be aware (SDS) for additional informa-
tion. The potential exists that selling mercury and/or mercury containing products into your state or country may be prohibited by
law.or mercury-containing products, or both, is prohibited by local or national law. Users must determine legality of sales in their
location.
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.
This test method is under the jurisdiction of ASTM International Committee D02 on Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility
of ASTM Subcommittee D02.14 on Stability, Cleanliness and Compatibility of Liquid Fuels. The technically equivalent standard as referenced is under the jurisdiction of
the Energy Institute Subcommittee SC-B-8.
This test method has been approved by the sponsoring committees and accepted by the Cooperating Societies in accordance with established procedures.
Current edition approved April 1, 2018July 1, 2022. Published June 2018August 2022. Originally approved in 1946. Last previous edition approved in 20122018 as
D873 – 12.D873 – 12 (2018). DOI: 10.1520/D0873-12R18.10.1520/D0873-22.
This test method has been developed through the cooperative effort between ASTM and the Energy Institute, London. ASTM and IP standards were approved by ASTM
and EI technical committees as being technically equivalent but that does not imply both standards are identical.
Further information can be found in the June 1978, January 1979, and June 1986 editions of the Institute of Petroleum Review.
*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
D873 − 22
2. Referenced Documents
2.1 ASTM Standards:
D381 Test Method for Gum Content in Fuels by Jet Evaporation
D525 Test Method for Oxidation Stability of Gasoline (Induction Period Method)
D4057 Practice for Manual Sampling of Petroleum and Petroleum Products
D5452 Test Method for Particulate Contamination in Aviation Fuels by Laboratory Filtration
E1 Specification for ASTM Liquid-in-Glass Thermometers
3. Terminology
3.1 The following definitions of terms are all expressed in terms of milligrams per 100 mL of sample, after “X” hours aging, “X”
being the accelerated aging (oxidation) period at 100°C.100 °C.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 insoluble gum, n—deposit adhering to the glass sample container after removal of the aged fuel, precipitate, and soluble gum.
3.2.1.1 Discussion—
Insoluble gum is obtained by measuring the increase in mass of the glass sample container.
3.2.2 potential gum, n—sum of the soluble and insoluble gum.
3.2.3 precipitate, n—sediment and suspended material in the aged fuel, obtained by filtering the aged fuel and washings from the
glass sample container.
3.2.4 soluble gum, n—deterioration products present at the end of a specific aging period. These deterioration products exist in
solution in the aged fuel and as the toluene-acetone soluble portion of the deposit on the glass sample container.
3.2.4.1 Discussion—
The soluble gum is obtained as a nonvolatile residue by evaporating the aged fuel and the toluene-acetone washings from the glass
sample container.
3.2.5 total potential residue, n—sum of the potential gum and the precipitate.
4. Summary of Test Method
4.1 The fuel is oxidized under prescribed conditions in a pressure vessel filled with oxygen. The amounts of soluble gum, insoluble
gum, and precipitate formed are weighed. (Warning—In addition to other precautions, to provide protection against the possibility
of explosive rupture of the pressure vessel, the pressure vessel should be operated behind an appropriate safety shield.)
5. Significance and Use
5.1 The results (of these tests) can be used to indicate storage stability of these fuels. The tendency of fuels to form gum and
deposits in these tests has not been correlated with field performance (and can vary markedly) with the formation of gum and
deposits under different storage conditions.
6. Apparatus
6.1 Oxidation Pressure Vessel, Burst Disc Assembly, Glass Sample Container and Cover, Accessories and Pressure Gage, as
described in the Annex to Test Method D525. (Warning—Provision shall be made to safely vent any expelled gases or flames
away from the operator, other personnel, or flammable materials as a safety precaution if the burst-disc ruptures.)
NOTE 2—Pressure vessels conforming to Test Method D525–80 are also suitable, but the specified burst-disc shall be attached. The burst disc assembly
shall be mechanically designed to ensure that it cannot be incorrectly fitted.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
D873 − 22
6.2 Thermometer, having a range as shown below and conforming to the requirements as prescribed in Specification E1, or
specifications for IP thermometers:
Thermometer Range Thermometer Number
ASTM IP
95 °C to 103 °C 22C 24C
NOTE 3—Other temperature sensing devices that cover the temperature range of interest, such as thermocouples or platinum resistance thermometers, that
can provide equivalent or better accuracy and precision, may be used in place of the thermometers specified in 6.2.
6.3 Drying Oven, air oven maintained at 100 °C to 150 °C.
6.4 Forceps, corrosion-resistant, steel.
6.5 Filtering Crucible, sintered-glass, fine porosity.
6.6 Oxidation Bath, as described in the Annex to Test Method D525. The liquid shall be water or a mixture of ethylene glycol and
water, as required. The temperature can be controlled thermostatically at 100 °C 6 0.2 °C, or by maintaining it at its boiling point,
which must be between 99.5 °C to 100.5 °C. If a liquid medium other than water is used, an appropriate mechanical stirrer/mixer
shall be used to maintain uniformity of the liquid bath at 100 °C 6 0.2 °C. A non self-resettable device shall be fitted on all new
baths to ensure that the heater is switched off if the liquid bath falls below a safe level. Users of older baths without this device
are strongly urged to have the equipment retrofitted to ensure safe operation.
NOTE 4—Electric heating blocks are known to be used. These blocks can have heating capacities, heating rates, and heat transfer characteristics that differ
from those of a liquid bath. An electric heating block may be used in place of the liquid bath as long as the sample heating rate and sample temperature
are demonstrated to be equivalent to that of the liquid bath.
6.7 Cooling Vessel—A desiccator or other type of tightly covered vessel for cooling the beakers before weighing. The use of a
drying agent is not recommended.
7. Reagents and Materials
7.1 Gum Solvent—A mixture of equal volumes of toluene and acetone.
7.2 Oxygen, commercially available extra dry oxygen of not less than 99.6 % purity.
8. Sampling
8.1 Sample in accordance with the procedure for oxidation stability, as described in Practice D4057.
9. Preparation of Apparatus
9.1 Thoroughly clean a glass sample container to remove traces of any adhering material. Immerse the container and its cover in
a mildly alkaline or neutral pH laboratory detergent cleaning solution. The type of detergent and conditions for its use need to be
established in each laboratory. The criterion for satisfactory cleaning shall be a matching of the quality of that obtained with
chromic acid cleaning solutions (or some other equivalently strong oxidizing non-chromium containing acid cleaning solutions)
on used sample containers and covers (fresh chromic acid, 6 h soaking period, rinsing with distilled water and drying). For this
comparison, visual appearance and mass loss on heating the glassware under test conditions may be used. Detergent cleaning
avoids the potential hazards and inconveniences related to the handling of highly corrosive and strongly oxidizing acid solutions;
this procedure remains the reference cleaning practice and, as such, may function as an alternate to the preferr
...