ASTM D6749-02(2018)
(Test Method)Standard Test Method for Pour Point of Petroleum Products (Automatic Air Pressure Method)
Standard Test Method for Pour Point of Petroleum Products (Automatic Air Pressure Method)
SIGNIFICANCE AND USE
5.1 The pour point of a petroleum product is an index of the lowest temperature of its utility for certain applications. Flow characteristics, like pour point, can be critical for the correct operation of lubricating systems, fuel systems, and pipeline operations.
5.2 Petroleum blending operations require precise measurement of the pour point.
5.3 Test results from this test method can be determined at either 1 °C or 3 °C intervals.
5.4 This test method yields a pour point in a format similar to Test Method D97/IP 15 when the 3 °C interval results are reported. However, when specification requires Test Method D97/IP 15, do not substitute this test method.
Note 2: Since some users may wish to report their results in a format similar to Test Method D97/IP 15 (in 3 °C intervals), the precision data were derived for the 3 °C intervals. For statements on bias relative to Test Method D97/IP 15, see 13.3.1.
5.5 This test method has better repeatability and reproducibility relative to Test Method D97/IP 15 as measured in the 1998 interlaboratory test program (see Section 13).
SCOPE
1.1 This test method covers the determination of pour point of petroleum products by an automatic apparatus that applies a slightly positive air pressure onto the specimen surface while the specimen is being cooled.
1.2 This test method is designed to cover the range of temperatures from −57 °C to +51 °C; however, the range of temperatures included in the (1998) interlaboratory test program only covered the temperature range from −51 °C to −11 °C.
1.3 Test results from this test method can be determined at either 1 °C or 3 °C testing intervals.
1.4 This test method is not intended for use with crude oils.
Note 1: The applicability of this test method on residual fuel samples has not been verified. For further information on the applicability, refer to 13.4.
1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.6 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.
1.7 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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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: D6749 − 02 (Reapproved 2018)
Standard Test Method for
Pour Point of Petroleum Products (Automatic Air Pressure
Method)
This standard is issued under the fixed designation D6749; 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.
INTRODUCTION
This test method covers an alternative procedure for the determination of pour point of petroleum
products using an automatic apparatus.
1. Scope 2. Referenced Documents
1.1 This test method covers the determination of pour point 2.1 ASTM Standards:
of petroleum products by an automatic apparatus that applies a D97Test Method for Pour Point of Petroleum Products
slightly positive air pressure onto the specimen surface while D4057Practice for Manual Sampling of Petroleum and
the specimen is being cooled. Petroleum Products
D4177Practice for Automatic Sampling of Petroleum and
1.2 This test method is designed to cover the range of
Petroleum Products
temperatures from −57°C to +51°C; however, the range of
temperatures included in the (1998) interlaboratory test pro- 2.2 Energy Institute Standard:
gram only covered the temperature range from −51°C to IP 15Test Method for Pour Point of Petroleum Products
−11°C.
3. Terminology
1.3 Test results from this test method can be determined at
either 1°C or 3°C testing intervals. 3.1 Definitions:
3.1.1 pour point, n—in petroleum products,lowesttempera-
1.4 This test method is not intended for use with crude oils.
tureatwhichmovementofthetestspecimenisobservedunder
NOTE 1—The applicability of this test method on residual fuel samples
has not been verified. For further information on the applicability, refer to prescribed conditions of test.
13.4.
3.2 Definitions of Terms Specific to This Standard:
1.5 The values stated in SI units are to be regarded as
3.2.1 air pressure, n—regulated slightly positive air pres-
standard. No other units of measurement are included in this
sure gently applied onto the specimen surface in the airtight
standard.
test jar that causes upward movement of the specimen in the
communicating tube, which has one end inserted into the test
1.6 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the specimen and the other end at atmospheric pressure.
responsibility of the user of this standard to establish appro-
3.2.2 no-flow point, n—in petroleum products, temperature
priate safety, health, and environmental practices and deter-
ofthetestspecimenatwhichawaxcrystalstructureofthetest
mine the applicability of regulatory limitations prior to use.
specimen or viscosity increase, or both, impedes movement of
1.7 This international standard was developed in accor-
thesurfaceofthetestspecimenundertheconditionsofthetest.
dance with internationally recognized principles on standard-
3.2.2.1 Discussion—The no-flow point occurs when, upon
ization established in the Decision on Principles for the
cooling, the formation of wax crystal structures or viscosity
Development of International Standards, Guides and Recom-
increase,orboth,hasprogressedtothepointwheretheapplied
mendations issued by the World Trade Organization Technical
observation device no longer detects movement under the
Barriers to Trade (TBT) Committee.
1 2
This test method is under the jurisdiction of ASTM Committee D02 on For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Subcommittee D02.07 on Flow Properties. Standards volume information, refer to the standard’s Document Summary page on
Current edition approved May 1, 2018. Published June 2018. Originally the ASTM website.
approved in 2002. Last previous edition approved in 2012 as D6749–02 (2012). Available from Energy Institute, 61 New Cavendish St., London, W1G 7AR,
DOI: 10.1520/D6749-02R18. U.K., http://www.energyinst.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D6749 − 02 (2018)
conditions of the test. The preceding observation temperature, controlled apparatus that is capable of heating and cooling a
at which flow of the test specimen is last observed, is the pour specimen, applying air pressure onto the specimen’s surface,
point. detecting the specimen’s surface movement, and then comput-
ing and reporting the pour point (see Fig. 1). The detail is
4. Summary of Test Method
described in Annex A1.
4.1 After inserting the test jar containing the specimen into
6.2 Test Jar, clear cylindrical glass with a flat bottom with
the automatic pour point apparatus and initiating the test
an approximate capacity of 12mL. Approximately 4.5mL of
program, the specimen is automatically heated to the desig-
sample specimen is contained when filled to the scribed line.
nated temperature and then cooled at a controlled rate. At
The test jar is fitted with a test jar cap assembly on its top to
temperature intervals of 1°C or 3°C, depending on the
form an air chamber over the test specimen.
selection made by the user prior to the test, a slightly positive
6.3 Test Jar Cap Assembly—Aplasticcapisinstalledontop
air pressure is gently applied onto the surface of the specimen
ofthetestjarwiththeprovisionofsealingair.Aglasstubewith
which is contained in an airtight test jar equipped with a
a metallic tip shall be inserted from underneath the plastic cap
communicatingtube.Sinceoneendofthecommunicatingtube
intotheroundholeinthecenterofthetestjarcap.Thetopend
is inserted into the specimen while the other end is maintained
oftheroundholeisconnectedtoanairpressuresensorbyway
at atmospheric pressure, a small amount of downward move-
of a vinyl tube. To supply air pressure to the specimen’s
ment or deformation of the specimen surface, as a result of the
surface, a vinyl tube connected to an air syringe is located
application of air pressure, is observed by means of upward
adjacent to the glass tube through an orifice in the plastic cap.
movement of the specimen in the communicating tube. This
When a specimen is to be tested, the test jar cap assembly is
upward movement of the specimen is detected by a pressure
installed on the test jar with the lower end of the glass tube
sensor which is installed at the atmospheric end of the
communicating tube. The lowest temperature at which defor-
mation of the specimen is observed upon application of air
This pour point analyzer is covered by a patent. If you are aware of an
pressure is recorded as the pour point in accordance with Test
alternative(s) to the patented item, please attach to your ballot return a description
Method D6749.
of the alternatives. All the suggestions will be considered by the committee.
5. Significance and Use
5.1 Thepourpointofapetroleumproductisanindexofthe
lowest temperature of its utility for certain applications. Flow
characteristics, like pour point, can be critical for the correct
operation of lubricating systems, fuel systems, and pipeline
operations.
5.2 Petroleum blending operations require precise measure-
ment of the pour point.
5.3 Test results from this test method can be determined at
either 1°C or 3°C intervals.
5.4 This test method yields a pour point in a format similar
to Test Method D97/IP 15 when the 3°C interval results are
reported. However, when specification requires Test Method
D97/IP 15, do not substitute this test method.
NOTE 2—Since some users may wish to report their results in a format
similar to Test Method D97/IP 15 (in 3°C intervals), the precision data
were derived for the 3°C intervals. For statements on bias relative toTest
Method D97/IP 15, see 13.3.1.
5.5 This test method has better repeatability and reproduc-
ibility relative to Test Method D97/IP 15 as measured in the
1998 interlaboratory test program (see Section 13).
6. Apparatus
4,5
6.1 Automatic Apparatus —The automatic pour point ap-
paratus described in this test method is a microprocessor
The sole source of supply of the apparatus known to the committee at this time
isTanaka model MPC series Pour PointAnalyzers available fromTanaka Scientific
Limited,Adachiku, Tokyo, Japan. Various models included in this model series are
differentiatedbytheircoolingcapacitiesornumberoftestheads,orboth.Ifyouare
aware of alternative suppliers, please provide this information to ASTM Interna-
tional Headquarters.Your comments will receive careful consideration at a meeting
of the responsible technical committee, which you may attend. FIG. 1 Automatic Apparatus
D6749 − 02 (2018)
insertedintothespecimeninthetestjar.Theglasstubeandthe 11.3 Select the desired test mode, including the pour point
test jar form a communicating tube.Atemperature sensor in a testing interval, according to the manufacturer’s instructions.
smalldiametermetallicsheathshallbeinstalledinthecenterof Shouldtheuserwishtoprovideresultswithasimilarformatto
the glass tube. Test Method D97/IP15, then testing at a 3°C interval shall be
selected. Start the automatic sample preheating function, and
6.4 Metallic Block Bath, a metallic block with a cylindrical
then enter the expected pour point (EPP). When the 3°C
hole to fit the test jar. The metallic block assembly shall have
testing interval is chosen, the EPP needs to be a multiple of
a provision for cooling/heating. A temperature sensor is em-
3°C.
bedded in the metallic block to monitor its temperature.
11.4 Start the test program. The sample is automatically
7. Reagents and Materials
preheatedbytheautomaticapparatusto45°CortoEPP+9°C,
7.1 CleaningAgents,capableofcleaninganddryingthetest whichever is higher, but no higher than 70°C, by maintaining
jar,temperaturesensor,andglasstubeaftereachtest.Chemical
the bath temperature at 48°C or EPP + 12°C, whichever is
agents such as alcohol, petroleum-based solvents, and acetone higher.
have been found suitable to use. (Warning——Flammable.)
11.5 After the preheating is completed, the specimen is
(Warning——May be harmful by itself or when evaporated.)
cooled down automatically.
11.5.1 The metallic block bath is cooled down at a rate of
8. Sampling
3°C⁄min to 4°C⁄min, to the EPP + 40°C.
8.1 Obtain a sample in accordance with Practice D4057 or
11.5.2 From the EPP + 40°C to the no-flow point, the
by Practice D4177.
metallic block bath is cooled at a rate of 0.8°C⁄min to
8.2 Samples of very viscous materials may be warmed until
1.1°C⁄min.
they are reasonably fluid before they are transferred; however,
11.6 As the specimen temperature reaches a predetermined
no sample shall be h
...
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: D6749 − 02 (Reapproved 2018)
Standard Test Method for
Pour Point of Petroleum Products (Automatic Air Pressure
Method)
This standard is issued under the fixed designation D6749; 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.
INTRODUCTION
This test method covers an alternative procedure for the determination of pour point of petroleum
products using an automatic apparatus.
1. Scope 2. Referenced Documents
1.1 This test method covers the determination of pour point 2.1 ASTM Standards:
of petroleum products by an automatic apparatus that applies a D97 Test Method for Pour Point of Petroleum Products
slightly positive air pressure onto the specimen surface while D4057 Practice for Manual Sampling of Petroleum and
the specimen is being cooled. Petroleum Products
D4177 Practice for Automatic Sampling of Petroleum and
1.2 This test method is designed to cover the range of
Petroleum Products
temperatures from −57 °C to +51 °C; however, the range of
temperatures included in the (1998) interlaboratory test pro- 2.2 Energy Institute Standard:
gram only covered the temperature range from −51 °C to IP 15 Test Method for Pour Point of Petroleum Products
−11 °C.
3. Terminology
1.3 Test results from this test method can be determined at
either 1 °C or 3 °C testing intervals.
3.1 Definitions:
3.1.1 pour point, n—in petroleum products, lowest tempera-
1.4 This test method is not intended for use with crude oils.
ture at which movement of the test specimen is observed under
NOTE 1—The applicability of this test method on residual fuel samples
prescribed conditions of test.
has not been verified. For further information on the applicability, refer to
13.4.
3.2 Definitions of Terms Specific to This Standard:
1.5 The values stated in SI units are to be regarded as
3.2.1 air pressure, n—regulated slightly positive air pres-
standard. No other units of measurement are included in this
sure gently applied onto the specimen surface in the airtight
standard.
test jar that causes upward movement of the specimen in the
1.6 This standard does not purport to address all of the communicating tube, which has one end inserted into the test
specimen and the other end at atmospheric pressure.
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro-
3.2.2 no-flow point, n—in petroleum products, temperature
priate safety, health, and environmental practices and deter-
of the test specimen at which a wax crystal structure of the test
mine the applicability of regulatory limitations prior to use.
specimen or viscosity increase, or both, impedes movement of
1.7 This international standard was developed in accor-
the surface of the test specimen under the conditions of the test.
dance with internationally recognized principles on standard-
3.2.2.1 Discussion—The no-flow point occurs when, upon
ization established in the Decision on Principles for the
cooling, the formation of wax crystal structures or viscosity
Development of International Standards, Guides and Recom-
increase, or both, has progressed to the point where the applied
mendations issued by the World Trade Organization Technical
observation device no longer detects movement under the
Barriers to Trade (TBT) Committee.
1 2
This test method is under the jurisdiction of ASTM Committee D02 on For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Subcommittee D02.07 on Flow Properties. Standards volume information, refer to the standard’s Document Summary page on
Current edition approved May 1, 2018. Published June 2018. Originally the ASTM website.
approved in 2002. Last previous edition approved in 2012 as D6749 – 02 (2012). Available from Energy Institute, 61 New Cavendish St., London, W1G 7AR,
DOI: 10.1520/D6749-02R18. U.K., http://www.energyinst.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D6749 − 02 (2018)
conditions of the test. The preceding observation temperature, controlled apparatus that is capable of heating and cooling a
at which flow of the test specimen is last observed, is the pour specimen, applying air pressure onto the specimen’s surface,
point. detecting the specimen’s surface movement, and then comput-
ing and reporting the pour point (see Fig. 1). The detail is
4. Summary of Test Method
described in Annex A1.
4.1 After inserting the test jar containing the specimen into
6.2 Test Jar, clear cylindrical glass with a flat bottom with
the automatic pour point apparatus and initiating the test
an approximate capacity of 12 mL. Approximately 4.5 mL of
program, the specimen is automatically heated to the desig-
sample specimen is contained when filled to the scribed line.
nated temperature and then cooled at a controlled rate. At
The test jar is fitted with a test jar cap assembly on its top to
temperature intervals of 1 °C or 3 °C, depending on the
form an air chamber over the test specimen.
selection made by the user prior to the test, a slightly positive
6.3 Test Jar Cap Assembly—A plastic cap is installed on top
air pressure is gently applied onto the surface of the specimen
of the test jar with the provision of sealing air. A glass tube with
which is contained in an airtight test jar equipped with a
a metallic tip shall be inserted from underneath the plastic cap
communicating tube. Since one end of the communicating tube
into the round hole in the center of the test jar cap. The top end
is inserted into the specimen while the other end is maintained
of the round hole is connected to an air pressure sensor by way
at atmospheric pressure, a small amount of downward move-
of a vinyl tube. To supply air pressure to the specimen’s
ment or deformation of the specimen surface, as a result of the
surface, a vinyl tube connected to an air syringe is located
application of air pressure, is observed by means of upward
adjacent to the glass tube through an orifice in the plastic cap.
movement of the specimen in the communicating tube. This
When a specimen is to be tested, the test jar cap assembly is
upward movement of the specimen is detected by a pressure
installed on the test jar with the lower end of the glass tube
sensor which is installed at the atmospheric end of the
communicating tube. The lowest temperature at which defor-
mation of the specimen is observed upon application of air
This pour point analyzer is covered by a patent. If you are aware of an
pressure is recorded as the pour point in accordance with Test
alternative(s) to the patented item, please attach to your ballot return a description
Method D6749.
of the alternatives. All the suggestions will be considered by the committee.
5. Significance and Use
5.1 The pour point of a petroleum product is an index of the
lowest temperature of its utility for certain applications. Flow
characteristics, like pour point, can be critical for the correct
operation of lubricating systems, fuel systems, and pipeline
operations.
5.2 Petroleum blending operations require precise measure-
ment of the pour point.
5.3 Test results from this test method can be determined at
either 1 °C or 3 °C intervals.
5.4 This test method yields a pour point in a format similar
to Test Method D97/IP 15 when the 3 °C interval results are
reported. However, when specification requires Test Method
D97/IP 15, do not substitute this test method.
NOTE 2—Since some users may wish to report their results in a format
similar to Test Method D97/IP 15 (in 3 °C intervals), the precision data
were derived for the 3 °C intervals. For statements on bias relative to Test
Method D97/IP 15, see 13.3.1.
5.5 This test method has better repeatability and reproduc-
ibility relative to Test Method D97/IP 15 as measured in the
1998 interlaboratory test program (see Section 13).
6. Apparatus
4,5
6.1 Automatic Apparatus —The automatic pour point ap-
paratus described in this test method is a microprocessor
The sole source of supply of the apparatus known to the committee at this time
is Tanaka model MPC series Pour Point Analyzers available from Tanaka Scientific
Limited, Adachiku, Tokyo, Japan. Various models included in this model series are
differentiated by their cooling capacities or number of test heads, or both. If you are
aware of alternative suppliers, please provide this information to ASTM Interna-
tional Headquarters. Your comments will receive careful consideration at a meeting
of the responsible technical committee, which you may attend. FIG. 1 Automatic Apparatus
D6749 − 02 (2018)
inserted into the specimen in the test jar. The glass tube and the 11.3 Select the desired test mode, including the pour point
test jar form a communicating tube. A temperature sensor in a testing interval, according to the manufacturer’s instructions.
small diameter metallic sheath shall be installed in the center of Should the user wish to provide results with a similar format to
the glass tube. Test Method D97/IP 15, then testing at a 3 °C interval shall be
selected. Start the automatic sample preheating function, and
6.4 Metallic Block Bath, a metallic block with a cylindrical
then enter the expected pour point (EPP). When the 3 °C
hole to fit the test jar. The metallic block assembly shall have
testing interval is chosen, the EPP needs to be a multiple of
a provision for cooling/heating. A temperature sensor is em-
3 °C.
bedded in the metallic block to monitor its temperature.
11.4 Start the test program. The sample is automatically
7. Reagents and Materials
preheated by the automatic apparatus to 45 °C or to EPP + 9°C,
7.1 Cleaning Agents, capable of cleaning and drying the test
whichever is higher, but no higher than 70 °C, by maintaining
jar, temperature sensor, and glass tube after each test. Chemical the bath temperature at 48 °C or EPP + 12 °C, whichever is
agents such as alcohol, petroleum-based solvents, and acetone
higher.
have been found suitable to use. (Warning——Flammable.)
11.5 After the preheating is completed, the specimen is
(Warning——May be harmful by itself or when evaporated.)
cooled down automatically.
11.5.1 The metallic block bath is cooled down at a rate of
8. Sampling
3 °C ⁄min to 4 °C ⁄min, to the EPP + 40 °C.
8.1 Obtain a sample in accordance with Practice D4057 or
11.5.2 From the EPP + 40 °C to the no-flow point, the
by Practice D4177.
metallic block bath is cooled at a rate of 0.8 °C ⁄min to
8.2 Samples of very viscous materials may be warmed until 1.1 °C ⁄min.
they are reasonably fluid before they are transferred; however,
11.6 As the specimen temperature reaches a predetermined
no sample shall be heated more than is absolutely necessary.
temperature, which is dependent on the EPP, the automatic
The sample shall not be heated and transferred into the test jar
apparatus starts testing for no-flow state by applying air
unless its temperature is 70 °C or lower.
pressure to the specimen surface at the programmed testing
NOTE 3—In the event the sample has been heated above this
interval. When the specimen is still in a fluid state, the
temperature, allow the sample to cool until its temperature is at least 70 °C
specimen level moves up in the glass tube as air pressure is
before transferring.
applied on the specimen surface; when the specimen reaches a
9. Preparation of Apparatus
no-flow state, the specimen level does not move at all in the
9.1 Install the automatic apparatus for operation in accor- glass tube. Upon detecting the no-flow point, the automatic
apparatus computes and displays the pour point, which is the
dance with the manufacturer’s instructions.
sum of the no-flow point temperature and the testing interval.
9.2 Clean and dry the test jar, temperature sensor, and glass
Also, the automatic apparatus stops cooling and starts heating
tube.
the specimen.
9.3 Turn on the main power switch of the automatic
11.6.1 Specimen Having Expected Pour Point Equal To or
apparatus.
Above +36 °C—The automatic apparatus starts testing for the
no-flow state at EPP + 9 °C.
10. Calibration and Standardization
11.6.2 Specimen Having Expected Pour Point Equal To or
10.1 Ensure that all of the manufacturer’s instructions for
Between +31 °C and +35 °C—The automatic apparatus starts
calibrating, checking, and operating the automatic apparatus
testing for the no-flow state at 45 °C.
are followed.
11.6.3 Specimen Having Expected Pour Point Equal To or
10.2 Check the position of the temperature sensor and glass Below +30 °C—The automatic apparatus starts testing for the
no-flow state at EPP + 15 °C.
tube according to the manufacturer’s instructions and, when
necessary, make appropriate adjustments.
11.7 Remove the test jar cap assembly and clean the test jar
and test jar cap assembly.
10.3 A sample with a well documented pour point can be
used to verify the performance of the automatic apparatus.
NOTE 4—Residual fuels have been known to be sensitive to thermal
Alternatively, a sample which has been extensively tested in a
history. In the case where a residual fuel sample is tested, refer to Test
pour point interlaboratory study can be used.
Method D97 for sample treatment.
11. Procedure
12. Report
11.1 Pour the sample specimen into the test jar to the scribed
12.1 Report the temperature recorded in 11.6 and the testing
mark. When necessary, heat the sample in a bath or oven until
interval as the pour point in accordance with Test Method
it is just sufficiently fluid to pour into the test jar. Samples with
D6749.
an expected pour point above 36 °C or samples which appear
solid at room temperature can be heated above 45 °C, but shall
not be heated above 70 °C.
11.2 Insert the charged test jar into the metallic block bath
and install the test jar cap assembly snugly.
D6749 − 02 (2018)
13. Precision and Bias 13.3 Relative Bias:
13.3.1 Pour point results at 3 °C testing intervals were
13.1 Precision—The precision of this test method as deter-
compared to the pour point results from Test Method D97.
mined by statistical examination of interlaboratory test results
Relative bias among certain samples was observed; however,
is as follows:
the observed bias does not appear to be of a systematic nature.
13.1.1 Pour Point at 3 °C Testing Intervals (Test
...
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: D6749 − 02 (Reapproved 2012) D6749 − 02 (Reapproved 2018)
Standard Test Method for
Pour Point of Petroleum Products (Automatic Air Pressure
Method)
This standard is issued under the fixed designation D6749; 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.
INTRODUCTION
This test method covers an alternative procedure for the determination of pour point of petroleum
products using an automatic apparatus.
1. Scope
1.1 This test method covers the determination of pour point of petroleum products by an automatic apparatus that applies a
slightly positive air pressure onto the specimen surface while the specimen is being cooled.
1.2 This test method is designed to cover the range of temperatures from −57−57 °C to +51°C;+51 °C; however, the range of
temperatures included in the (1998) interlaboratory test program only covered the temperature range from −51−51 °C to
−11°C.−11 °C.
1.3 Test results from this test method can be determined at either 11 °C or 3°C3 °C testing intervals.
1.4 This test method is not intended for use with crude oils.
NOTE 1—The applicability of this test method on residual fuel samples has not been verified. For further information on the applicability, refer to 13.4.
1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.6 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.
1.7 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:
D97 Test Method for Pour Point of Petroleum Products
D4057 Practice for Manual Sampling of Petroleum and Petroleum Products
D4177 Practice for Automatic Sampling of Petroleum and Petroleum Products
2.2 Energy Institute Standard:
IP 15 Test Method for Pour Point of Petroleum Products
3. Terminology
3.1 Definitions:
3.1.1 pour point, n—in petroleum products, lowest temperature at which movement of the test specimen is observed under
prescribed conditions of test.
This test method is under the jurisdiction of ASTM Committee D02 on Petroleum Products Products, Liquid Fuels, and Lubricants and is the direct responsibility of
Subcommittee D02.07 on Flow Properties.
Current edition approved Nov. 1, 2012May 1, 2018. Published November 2012June 2018. Originally approved in 2002. Last previous edition approved in 20072012 as
D6749D6749 – 02 (2012).–02 (2007). DOI: 10.1520/D6749-02R12.10.1520/D6749-02R18.
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D6749 − 02 (2018)
3.2 Definitions of Terms Specific to This Standard:
3.2.1 air pressure, n—regulated slightly positive air pressure gently applied onto the specimen surface in the airtight test jar that
causes upward movement of the specimen in the communicating tube, which has one end inserted into the test specimen and the
other end at atmospheric pressure.
3.2.2 no-flow point, n—in petroleum products, temperature of the test specimen at which a wax crystal structure of the test
specimen or viscosity increase, or both, impedes movement of the surface of the test specimen under the conditions of the test.
3.2.2.1 Discussion—
The no-flow point occurs when, upon cooling, the formation of wax crystal structures or viscosity increase, or both, has progressed
to the point where the applied observation device no longer detects movement under the conditions of the test. The preceding
observation temperature, at which flow of the test specimen is last observed, is the pour point.
4. Summary of Test Method
4.1 After inserting the test jar containing the specimen into the automatic pour point apparatus and initiating the test program,
the specimen is automatically heated to the designated temperature and then cooled at a controlled rate. At temperature intervals
of 11 °C or 3°C,3 °C, depending on the selection made by the user prior to the test, a slightly positive air pressure is gently applied
onto the surface of the specimen which is contained in an airtight test jar equipped with a communicating tube. Since one end of
the communicating tube is inserted into the specimen while the other end is maintained at atmospheric pressure, a small amount
of downward movement or deformation of the specimen surface, as a result of the application of air pressure, is observed by means
of upward movement of the specimen in the communicating tube. This upward movement of the specimen is detected by a pressure
sensor which is installed at the atmospheric end of the communicating tube. The lowest temperature at which deformation of the
specimen is observed upon application of air pressure is recorded as the pour point in accordance with Test Method D6749.
5. Significance and Use
5.1 The pour point of a petroleum product is an index of the lowest temperature of its utility for certain applications. Flow
characteristics, like pour point, can be critical for the correct operation of lubricating systems, fuel systems, and pipeline
operations.
5.2 Petroleum blending operations require precise measurement of the pour point.
5.3 Test results from this test method can be determined at either 11 °C or 3°C3 °C intervals.
5.4 This test method yields a pour point in a format similar to Test Method D97/IP 15 when the 3°C3 °C interval results are
reported. However, when specification requires Test Method D97/IP 15, do not substitute this test method.
NOTE 2—Since some users may wish to report their results in a format similar to Test Method D97/IP 15 (in 3°C3 °C intervals), the precision data were
derived for the 3°C3 °C intervals. For statements on bias relative to Test Method D97/IP 15, see 13.3.1.
5.5 This test method has better repeatability and reproducibility relative to Test Method D97/IP 15 as measured in the 1998
interlaboratory test program (see Section 13).
6. Apparatus
4,5
6.1 Automatic Apparatus —The automatic pour point apparatus described in this test method is a microprocessor controlled
apparatus that is capable of heating and cooling a specimen, applying air pressure onto the specimen’s surface, detecting the
specimen’s surface movement, and then computing and reporting the pour point (see Fig. 1). The detail is described in Annex A1.
6.2 Test Jar, clear cylindrical glass with a flat bottom with an approximate capacity of 12 mL. Approximately 4.5 mL 12 mL.
Approximately 4.5 mL of sample specimen is contained when filled to the scribed line. The test jar is fitted with a test jar cap
assembly on its top to form an air chamber over the test specimen.
6.3 Test Jar Cap Assembly—A plastic cap is installed on top of the test jar with the provision of sealing air. A glass tube with
a metallic tip shall be inserted from underneath the plastic cap into the round hole in the center of the test jar cap. The top end
of the round hole is connected to an air pressure sensor by way of a vinyl tube. To supply air pressure to the specimen’s surface,
a vinyl tube connected to an air syringe is located adjacent to the glass tube through an orifice in the plastic cap. When a specimen
is to be tested, the test jar cap assembly is installed on the test jar with the lower end of the glass tube inserted into the specimen
The sole source of supply of the apparatus known to the committee at this time is Tanaka model MPC series Pour Point Analyzers available from Tanaka Scientific
Limited, Adachiku, Tokyo, Japan. Various models included in this model series are differentiated by their cooling capacities or number of test heads, or both. 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.
This pour point analyzer is covered by a patent. If you are aware of an alternative(s) to the patented item, please attach to your ballot return a description of the
alternatives. All the suggestions will be considered by the committee.
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FIG. 1 Automatic Apparatus
in the test jar. The glass tube and the test jar form a communicating tube. A temperature sensor in a small diameter metallic sheath
shall be installed in the center of the glass tube.
6.4 Metallic Block Bath, a metallic block with a cylindrical hole to fit the test jar. The metallic block assembly shall have a
provision for cooling/heating. A temperature sensor is embedded in the metallic block to monitor its temperature.
7. Reagents and Materials
7.1 Cleaning Agents, capable of cleaning and drying the test jar, temperature sensor, and glass tube after each test. Chemical
agents such as alcohol, petroleum-based solvents, and acetone have been found suitable to use. (Warning— Warning—
Flammable.) (Warning—Warning—May be harmful by itself or when evaporated.)
8. Sampling
8.1 Obtain a sample in accordance with Practice D4057 or by Practice D4177.
8.2 Samples of very viscous materials may be warmed until they are reasonably fluid before they are transferred; however, no
sample shall be heated more than is absolutely necessary. The sample shall not be heated and transferred into the test jar unless
its temperature is 70°C70 °C or lower.
NOTE 3—In the event the sample has been heated above this temperature, allow the sample to cool until its temperature is at least 70°C70 °C before
transferring.
9. Preparation of Apparatus
9.1 Install the automatic apparatus for operation in accordance with the manufacturer’s instructions.
9.2 Clean and dry the test jar, temperature sensor, and glass tube.
9.3 Turn on the main power switch of the automatic apparatus.
D6749 − 02 (2018)
10. Calibration and Standardization
10.1 Ensure that all of the manufacturer’s instructions for calibrating, checking, and operating the automatic apparatus are
followed.
10.2 Check the position of the temperature sensor and glass tube according to the manufacturer’s instructions and, when
necessary, make appropriate adjustments.
10.3 A sample with a well documented pour point can be used to verify the performance of the automatic apparatus.
Alternatively, a sample which has been extensively tested in a pour point interlaboratory study can be used.
11. Procedure
11.1 Pour the sample specimen into the test jar to the scribed mark. When necessary, heat the sample in a bath or oven until
it is just sufficiently fluid to pour into the test jar. Samples with an expected pour point above 36°C36 °C or samples which appear
solid at room temperature can be heated above 45°C,45 °C, but shall not be heated above 70°C.70 °C.
11.2 Insert the charged test jar into the metallic block bath and install the test jar cap assembly snugly.
11.3 Select the desired test mode, including the pour point testing interval, according to the manufacturer’s instructions. Should
the user wish to provide results with a similar format to Test Method D97/IP 15, then testing at a 3°C3 °C interval shall be selected.
Start the automatic sample preheating function, and then enter the expected pour point (EPP). When the 3°C3 °C testing interval
is chosen, the EPP needs to be a multiple of 3°C.3 °C.
11.4 Start the test program. The sample is automatically preheated by the automatic apparatus to 45°C45 °C or to EPP + 9°C,
whichever is higher, but no higher than 70°C,70 °C, by maintaining the bath temperature at 48°C48 °C or EPP + 12°C,12 °C,
whichever is higher.
11.5 After the preheating is completed, the specimen is cooled down automatically.
11.5.1 The metallic block bath is cooled down at a rate of 33 °C ⁄min to 4°C/min,4 °C ⁄min, to the EPP + 40°C.40 °C.
11.5.2 From the EPP + 40°C40 °C to the no-flow point, the metallic block bath is cooled at a rate of 0.80.8 °C ⁄min to
1.1°C/min.1.1 °C ⁄min.
11.6 As the specimen temperature reaches a predetermined temperature, which is dependent on the EPP, the automatic apparatus
starts testing for no-flow state by applying air pressure to the specimen surface at the programmed testing interval. When the
specimen is still in a fluid state, the specimen level moves up in the glass tube as air pressure is applied on the specimen surface;
when the specimen reaches a no-flow state, the specimen level does not move at all in the glass tube. Upon detecting the no-flow
point, the automatic apparatus computes and displays the pour point, which is t97hethe sum of the no-flow point temperature and
the testing interval. Also, the automatic apparatus stops cooling and starts heating the specimen.
11.6.1 Specimen Having Expected Pour Point Equal To or Above +36°C—+36 °C—The automatic apparatus starts testing for
the no-flow state at EPP + 9°C.9 °C.
11.6.2 Specimen Having Expected Pour Point Equal To or Between +31°C+31 °C and +35°C—+35 °C—The automatic
apparatus starts testing for the no-flow state at 45°C.45 °C.
11.6.3 Specimen Having Expected Pour Point Equal To or Below +30°C—+30 °C—The automatic apparatus starts testing for
the no-flow state at EPP + 15°C.15 °C.
11.7 Remove the test jar cap assembly and clean the test jar and test jar cap assembly.
NOTE 4—Residual fuels have been known to be sensitive to thermal history. In the case where a residual fuel sample is tested, refer to Test Method
D97 for sample treatment.
12. Report
12.1 Report the temperatu
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