ASTM D525-12a(2019)
(Test Method)Standard Test Method for Oxidation Stability of Gasoline (Induction Period Method)
Standard Test Method for Oxidation Stability of Gasoline (Induction Period Method)
SIGNIFICANCE AND USE
5.1 The induction period may be used as an indication of the tendency of motor gasoline to form gum in storage. It should be recognized, however, that its correlation with the formation of gum in storage may vary markedly under different storage conditions and with different gasolines.
SCOPE
1.1 This test method covers the determination of the stability of gasoline in finished form only, under accelerated oxidation conditions. (Warning—This test method2 is not intended for determining the stability of gasoline components, particularly those with a high percentage of low boiling unsaturated compounds, as these may cause explosive conditions within the apparatus. However, because of the unknown nature of certain samples, the pressure vessel assembly shall include a safety burst-disc in order to safeguard the operator.)
Note 1: For measurement of oxidation stability of gasoline by measurement of potential gum, refer to Test Method D873, or IP Test Method 138.
Note 2: The precision data were developed with gasolines derived from hydrocarbon sources only without oxygenates.
1.2 The accepted SI unit of pressure is the kilo Pascal (kPa), and 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
Relations
Standards Content (Sample)
This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: D525 − 12a (Reapproved 2019) British Standard 4347
Designation: 40/97
Standard Test Method for
Oxidation Stability of Gasoline (Induction Period Method)
This standard is issued under the fixed designation D525; 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-
mine the applicability of regulatory limitations prior to use.
1.1 This test method covers the determination of the stabil-
1.5 This international standard was developed in accor-
ity of gasoline in finished form only, under accelerated oxida-
dance with internationally recognized principles on standard-
tion conditions. (Warning—This test method is not intended
ization established in the Decision on Principles for the
for determining the stability of gasoline components, particu-
Development of International Standards, Guides and Recom-
larly those with a high percentage of low boiling unsaturated
mendations issued by the World Trade Organization Technical
compounds, as these may cause explosive conditions within
Barriers to Trade (TBT) Committee.
the apparatus. However, because of the unknown nature of
certain samples, the pressure vessel assembly shall include a
2. Referenced Documents
safety burst-disc in order to safeguard the operator.)
2.1 ASTM Standards:
NOTE 1—For measurement of oxidation stability of gasoline by
measurement of potential gum, refer to Test Method D873,orIPTest D873 Test Method for Oxidation Stability of Aviation Fuels
Method 138.
(Potential Residue Method)
NOTE 2—The precision data were developed with gasolines derived
D4057 Practice for Manual Sampling of Petroleum and
from hydrocarbon sources only without oxygenates.
Petroleum Products
1.2 The accepted SI unit of pressure is the kilo Pascal (kPa),
E1 Specification for ASTM Liquid-in-Glass Thermometers
and of temperature is °C.
2.2 Energy Institute Standards:
1.3 WARNING—Mercury has been designated by many
IP-138 Test Method for Oxidation Stability, Aviation Gaso-
regulatory agencies as a hazardous substance that can cause
line
serious medical issues. Mercury, or its vapor, has been dem-
Part IV— Petroleum and its Products
onstrated to be hazardous to health and corrosive to materials.
Use Caution when handling mercury and mercury-containing
3. Terminology
products. See the applicable product Safety Data Sheet (SDS)
3.1 Definitions of Terms Specific to This Standard:
for additional information. The potential exists that selling
3.1.1 break point, n—the point in the pressure-time curve
mercury or mercury-containing products, or both, is prohibited
that is preceded by a pressure drop of exactly 14 kPa within
by local or national law. Users must determine legality of sales
15 min and succeeded by a drop of not less than 14 kPa in
in their location.
15 min.
1.4 This standard does not purport to address all of the
3.1.2 induction period, n—the time elapsed between the
safety concerns, if any, associated with its use. It is the
placing of the pressure vessel in the bath and the break point at
responsibility of the user of this standard to establish appro-
100 °C.
This test method is under the jurisdiction of ASTM Committee D02 on
Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Subcommittee D02.14 on Stability, Cleanliness and Compatibility of Liquid Fuels. contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
This test method has been approved by the sponsoring committees and accepted Standards volume information, refer to the standard’s Document Summary page on
by the Cooperating Societies in accordance with established procedures. the ASTM website.
Current edition approved Dec. 1, 2019. Published December 2019. Originally Available from Energy Institute, 61 New Cavendish St., London WIM, 8AR
approved in 1939. Last previous edition approved in 2012 as D525 – 12a. DOI: U.K.
10.1520/D0525-12AR19. Aconvenienttemplateformeasuringthebreakpointisdescribedinthepaperby
Further information can be found in the June 1978, January 1979, and June Korb, E. L., “Induction Period Calculator,” ASTM Bulletin, No. 153, August 1948,
1986 editions of the Institute of Petroleum Review. pp. 99–102.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D525 − 12a (2019)
4. Summary of Test Method glassware must not change by more than 60.5 mg between
cleaning and heating/cooling cycles. Detergent cleaning avoids
4.1 The sample is oxidized in a pressure vessel initially
the potential hazards and inconveniences related to handling
filled at 15 °C to 25 °C with oxygen pressure at 690 kPa to
corrosive chromic acid solutions; this procedure remains the
705 kPa and heated at a temperature between 98 °C and
reference cleaning practice and as such may function as an
102 °C. The pressure is recorded continuously or read at stated
alternate to the preferred procedure, cleaning with detergent
intervals until the breakpoint is reached. The time required for
solutions.
the sample to reach this point is the observed induction period
at the temperature of test, from which the induction period at
9.2 Remove container and cover from the cleaning solution
100 °C can be calculated. (Warning—In addition to other
by means of corrosion-resistant steel forceps and handle only
precautions, to provide protection against the possibility of
with forceps thereafter. Wash thoroughly, first with tap water,
explosive rupture of the pressure vessel, the pressure vessel
then with distilled water, and dry in an oven at 100 °C to
should be operated behind an appropriate safety shield.)
150 °C for at least 1 h.
9.3 Drain any gasoline from the pressure vessel and wipe
5. Significance and Use
the inside of the pressure vessel and pressure vessel closure,
5.1 Theinductionperiodmaybeusedasanindicationofthe
first with a clean cloth moistened with gum solvent and then
tendency of motor gasoline to form gum in storage. It should
with a clean dry cloth. Remove the filler rod from the stem and
be recognized, however, that its correlation with the formation
carefully clean any gum or gasoline from the stem, rod, and
of gum in storage may vary markedly under different storage
needle valve with gum solvent. The pressure vessel, the valve,
conditions and with different gasolines.
and all connecting lines shall be thoroughly dry before each
test is started. (Warning—Volatile peroxides which may have
6. Apparatus
formed during a previous test may accumulate in the
6.1 Oxidation Pressure Vessel, Glass Sample Container and
equipment, producing a potentially explosive environment.
Cover, Accessories, Pressure Gage, and Oxidation Bath, as
Special care in cleaning after each test is needed to ensure the
described in Annex A1.
filler rod, stem, and needle valve are free of these peroxides.)
6.2 Thermometer, having a range as shown as follows and
conforming to the requirements as prescribed in Specification
10. Procedure
E1 or in the specifications for IP thermometers:
10.1 Bring the pressure vessel and the gasoline to be tested
NOTE 3—Other temperature sensing devices that cover the temperature
to a temperature of 15 °C to 25 °C. Place the glass sample
range of interest, such as thermocouples or platinum resistance
container in the pressure vessel and add 50 mL 6 1 mL of test
thermometers, that can provide equivalent or better accuracy and
specimen. Alternatively, transfer 50 mL 6 1 mL of test speci-
precision, may be used in place of thermometers specified in 6.2.
men into the glass sample container first, before placing the
Thermometer Number
glass sample container into the pressure vessel. Cover the
Temperature Range ASTM IP
95 °C to 103 °C 22C 24C
sample container, close the pressure vessel, and using a quick
release air coupling introduce oxygen until a pressure of
7. Reagents and Materials
690 kPa to 705 kPa is attained. Allow the gas in the bomb to
7.1 Gum Solvent—Mixture of equal volumes of toluene and
escape slowly in order to flush out the air originally present
acetone, both of which shall be of 99 % minimum purity.
(Release the pressure at a slow uniform rate through the needle
valve at a rate not to exceed 345 kPa per min). Introduce
7.2 Oxygen—Commercially-available extra-dry oxygen of
oxygen again until a pressure of 690 kPa to 705 kPa is attained
not less than 99.6 % purity.
and observe for leaks, ignoring an initial rapid drop in pressure
8. Sampling (generally not over 40 kPa) which may be observed because of
the solution of oxygen in the sample.When the rate of pressure
8.1 Sample in accordance with the procedure for oxidation
drop does not exceed 7 kPa in 10 min, assume the absence of
stability as described in Practice D4057.
leaks and proceed with the test without repressuring.
9. Preparation of Apparatus
10.2 Place the charged pressure vessel in the vigorously
9.1 Wash the glass sample container with gum solvent until boiling water bath, or appropriate liquid bath equipped with
free from gum. Rinse thoroughly with water and immerse the mechanical stirring, being careful to avoid shaking, and record
sample container and cover in detergent cleaning solution. The the time of immersion as the starting time. Maintain the
type of detergent and conditions for its use shall match the temperature of the liquid bath between 98 °C and 102 °C.
cleanliness obtained by the use of a strongly oxidizing agent Observe the temperature to the nearest 0.1 °C at intervals
such as chromosulfuric acid, ammonium peroxydisulfate in during the test, and record the average temperature to the
concentrated sulfuric acid at approximately 8 G.⁄L, or sulfuric nearest 0.1 °C as the temperature of the test. Make a continu-
acid itself, soaking for at least 12 h, followed by rinses in tap ous record of the pressures in the pressure vessel, or if an
water, distilled water and then acetone. For comparison, visual indicating pressure gage is used, take pressure readings at
appearance and weight loss on heating the glassware under test 15 min intervals or less. If, during the initial 30 min of the test,
conditions may be used. Glassware needs to show no signs of a leak develops (as indicated by a steady drop in pressure
discoloration or particulates on the surface. The weight of considerably in excess of 14 kPa in 15 min) discard the test.
D525 − 12a (2019)
Continue the test until reaching a point preceded by a pressure 12. Report
drop of exactly 14 kPa in 15 min and succeeded by a drop of
12.1 Report the Induction period at 100 °C, calculated as in
not less than 14 kPa in 15 min or until the induction period
11.2 to the nearest 1 min.
exceeds the product specification. If no breakpoint is observed
12.2 If the test was stopped prior to observing the pressure
at the termination of the test, refer to Section 12 for reporting
drop required in 10.2, but after the product specification was
the result. (Warning—If a boiling water bath is used and the
exceeded, then report the result as being greater than N min,
test is made in a region where the atmospheric pressure is
where N is the product specification in min.
consistently below normal (101.3 kPa), it is permissible to add
a liquid with higher boiling point, such as ethylene glycol, to
12.3 If a slow oxidation of the sample is occurring rather
the water in order to maintain the operating temperature of the
than a breakpoint as defined in 10.2, then report the sample as
bathintheneighborhoodof100 °C.Ifaliquidotherthanwater
a slow oxidizing fuel with the total time for the test and the
is used, be sure the liquid is compatible with the seals in the
overall pressure drop from the start of the test.Aprecision and
pressure vessel.)
bias statement has not been determined for this case.
10.3 Record the number of minutes from the time the
13. Precision and Bias
pressure vessel is placed in the bath until the breakpoint has
been reached as the observed induction period at the tempera-
13.1 The precision of the test method as determined by
ture of the test.
statistical examination of interlaboratory test results is as
follows:
10.4 Cool the pressure vessel to approximately room tem-
13.1.1 Repeatability—The difference between two test
perature within 30 min after removal from the bath, using
results, obtained by the same operator with the same apparatus
ambient air or water ≤35 °C, before releasing the pressure
under constant operating conditions on identical test material,
slowly from the pressure vessel through the needle valve at a
would in the long run, in the normal and correct operation of
rate not exceeding 345 kPa per minute. Wash the pressure
the test method, exceed the following values only in one case
vessel and sample container in preparation for the next test.
in twenty: 5 %.
11. Calculation
13.1.2 Reproducibility—The difference between two single
and independent results obtained by different operators work-
11.1 The number of minutes from the time the pressure
ing in different laboratories on identical test material would, in
vessel is placed in the bath until the breakpoint has been
the long run, in the normal and correct operation of the test
reached is the observed induction period at the temperature of
method, exceed the following values only in one case in
the test.
twenty: 10 %.
11.2 Method of Calculation—Calculate the induction period
13.2 Bias—There being no criteria for measuring bias in
at 100 °C from one of the following equations: When the test
these test-product combinations, no statement of bias can be
temperature is above 100 °C:
made.
Induction period at 100 °C 5 ~IP !~110.101~t 2 100!! (1)
t a
NOTE 4—The precision values given above for induction period were
When the test temperature is below 100°C:
obtained using a boiling water bath only as the heat source. Therefore,
these precision values are not necessarily applicable to induction period
Induction period at 100 °C,min 5 ~IP !/~110.101~100 2 t !! (2)
t b
results obtained using other heat sources.
where:
IP = induction period, min, at the temperature of the test, 14. Keywords
t
t = test temperature when above 100 °C, °C, and
...
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