ASTM D7647-10(2018)
(Test Method)Standard Test Method for Automatic Particle Counting of Lubricating and Hydraulic Fluids Using Dilution Techniques to Eliminate the Contribution of Water and Interfering Soft Particles by Light Extinction
Standard Test Method for Automatic Particle Counting of Lubricating and Hydraulic Fluids Using Dilution Techniques to Eliminate the Contribution of Water and Interfering Soft Particles by Light Extinction
SIGNIFICANCE AND USE
5.1 This test method is intended for use in analytical laboratories including onsite in-service oil analysis laboratories.
5.2 Hard particles in lubricating or fluid power systems have a detrimental effect on the system as they cause operating components to wear and also accelerate the degradation of the oil. Hard particles in the oil originate from a variety of sources including generation from within an operating fluid system or contamination, which may occur during the storage and handling of new oils or via ingress into an operating fluid system.
5.3 High levels of contaminants can cause filter blockages and hard particles can have a serious impact on the life of pumps, pistons, gears, bearings, and other moving parts by accelerating wear and erosion.
5.4 Particle count results can be used to aid in assessing the capability of the filtration system responsible for cleaning the fluid, determining if off-line recirculating filtration is needed to clean up the fluid system, or aiding in the decision of whether or not a fluid change is required.
5.5 To accurately measure hard particle contamination levels, it is necessary to negate the particle counts contributed by the presence of small levels of free water. This method includes a process by which this can be accomplished using a water-masking diluent technique whereby water droplets of a size below the target level are finely distributed.
5.6 Certain additives or additive by-products that are semi-insoluble or insoluble in oil, namely the polydimethylsiloxane defoamant additive and oxidation by-products, are known to cause light scattering in automatic particle counters, which in turn causes falsely high counts. These and similar materials are commonly termed “soft particles” (see 3.1.6) and are not known to directly increase wear and erosion within an operating system. The contribution of these particles to the particle size cumulative count is negated with this method.
5.7 The use of dilution i...
SCOPE
1.1 This test method covers the determination of particle concentration and particle size distribution in new and in-service oils used for lubrication and hydraulic purposes.
1.2 Particles considered are in the range from 4 µm (c) to 200 µm (c) with the upper limit being dependent on the specific automatic particle counter being used.
Note 1: For the purpose of this test method, water droplets not masked by the diluent procedure are detected as particles, and agglomerated particles are detected and reported as a single larger particle.
Note 2: The subscript (c) is used to denote that the apparatus has been calibrated in accordance with ISO 11171. This subscript (c) strictly only applies to particles up to 50 µm.
1.3 Lubricants that can be analyzed by this test method are categorized as petroleum products or synthetic based products, such as: polyalpha olefin, polyalkylene glycol, or phosphate ester. Applicable viscosity range is up to 1000 mm2/s at 40 °C. This procedure may be appropriate for other petroleum and synthetic based lubricants not included in the precision statement.
1.4 Samples containing visible particles may not be suitable for analysis using this test method.
1.5 Samples that are opaque after dilution are not suitable for analysis using this test method.
1.6 The test method is specific to automatic particle counters that use the light extinction principle and are calibrated according to the latest revision of ISO 11171.
1.7 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.8 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.
1.9 This international standard was d...
General Information
Relations
Buy Standard
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: D7647 − 10 (Reapproved 2018)
Standard Test Method for
Automatic Particle Counting of Lubricating and Hydraulic
Fluids Using Dilution Techniques to Eliminate the
Contribution of Water and Interfering Soft Particles by Light
Extinction
This standard is issued under the fixed designation D7647; 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 1.8 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 determination of particle
responsibility of the user of this standard to establish appro-
concentration and particle size distribution in new and in-
priate safety, health, and environmental practices and deter-
service oils used for lubrication and hydraulic purposes.
mine the applicability of regulatory limitations prior to use.
1.2 Particles considered are in the range from 4 µm to
1.9 This international standard was developed in accor-
(c)
200 µm with the upper limit being dependent on the specific
(c) dance with internationally recognized principles on standard-
automatic particle counter being used.
ization established in the Decision on Principles for the
NOTE1—Forthepurposeofthistestmethod,waterdropletsnotmasked
Development of International Standards, Guides and Recom-
by the diluent procedure are detected as particles, and agglomerated
mendations issued by the World Trade Organization Technical
particles are detected and reported as a single larger particle.
Barriers to Trade (TBT) Committee.
NOTE 2—The subscript is used to denote that the apparatus has been
(c)
calibrated in accordance with ISO 11171. This subscript strictly only
(c)
applies to particles up to 50 µm. 2. Referenced Documents
1.3 Lubricants that can be analyzed by this test method are 2.1 ASTM Standards:
D4057 Practice for Manual Sampling of Petroleum and
categorized as petroleum products or synthetic based products,
such as: polyalpha olefin, polyalkylene glycol, or phosphate Petroleum Products
D4177 Practice for Automatic Sampling of Petroleum and
ester.Applicable viscosity range is up to 1000 mm /s at 40 °C.
This procedure may be appropriate for other petroleum and Petroleum Products
D6786 Test Method for Particle Count in Mineral Insulating
synthetic based lubricants not included in the precision state-
ment. Oil Using Automatic Optical Particle Counters
2.2 ISO Standards:
1.4 Samples containing visible particles may not be suitable
ISO 3722 Hydraulic fluid power—Fluid sample
for analysis using this test method.
containers—Qualifying and controlling cleaning methods
1.5 Samples that are opaque after dilution are not suitable
ISO 4406 Hydraulic fluid power—Fluids—Method for cod-
for analysis using this test method.
ing level of contamination by solid particles
1.6 The test method is specific to automatic particle coun- ISO 11171 Hydraulic fluid power—Calibration of automatic
ters that use the light extinction principle and are calibrated particle counters for liquids
according to the latest revision of ISO 11171.
3. Terminology
1.7 The values stated in SI units are to be regarded as
3.1 Definitions:
standard. No other units of measurement are included in this
3.1.1 For the purposes of this test method, the following
standard.
definitions apply:
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 D02.96.05 on In-Service Lubricants Particle Counting Practices and contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Techniques. Standards volume information, refer to the standard’s Document Summary page on
Current edition approved April 1, 2018. Published May 2018. Originally the ASTM website.
approved in 2010. Last previous edition approved in 2010 as D7647 – 10. DOI: Available fromAmerican National Standards Institute (ANSI), 25 W. 43rd St.,
10.1520/D7647-10R18. 4th Floor, New York, NY 10036, http://www.ansi.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D7647 − 10 (2018)
3.1.2 coincidence, n—thepresenceofmorethanoneparticle 4.4 Dilute with appropriate diluent for the sample type.
in the sensing zone of a particle analyzer at the same time,
4.5 Agitate diluted sample.
causing incorrect sizing and incorrect counting of the particle
4.6 Degas sample.
present. The coincidence limit of the counter is determined by
4.7 Begin testing within 90 s (or repeat agitation and degas-
the maximum acceptable concentration of particles in the
sing).
sensing zone and is supplied by the instrument manufacturer.
Refer to Section 3.4 in ISO 11171.
4.8 Obtain particle counts in triplicate (for sample and
method blank).
3.1.3 diluent, n—a solvent listed in Annex A1, Table A1.1,
having viscosity less than 10 mm /s at 40 °C that is physically
4.9 Analyze data and conduct validity checks.
and chemically compatible with the apparatus used and easily
4.10 Report results.
soluble at room temperature with the sample lubricant or
hydraulic fluid. 5. Significance and Use
3.1.4 emulsified water, n—water that exists in oil between
5.1 This test method is intended for use in analytical
the states of fully dissolved and phase-separated. An emulsi-
laboratories including onsite in-service oil analysis laborato-
fying agent in the oil causes the two immiscible liquids to
ries.
coexist in a heterogeneous mixture.
5.2 Hardparticlesinlubricatingorfluidpowersystemshave
3.1.5 free water, n—water that exists in a separate phase in
a detrimental effect on the system as they cause operating
an oil sample. This occurs when the water content of the oil
components to wear and also accelerate the degradation of the
exceeds the water holding capacity of the oil.
oil. Hard particles in the oil originate from a variety of sources
including generation from within an operating fluid system or
3.1.6 interfering soft particles, n—anundissolved,dispersed
contamination, which may occur during the storage and han-
material (such as an additive) within an oil blend or substance
dling of new oils or via ingress into an operating fluid system.
that is formed during the service life of an oil blend.
3.1.6.1 Discussion—When these substances are present in a
5.3 High levels of contaminants can cause filter blockages
sample and not completely solubilized, they are likely to be
and hard particles can have a serious impact on the life of
counted by an optical particle counter in a similar manner to
pumps, pistons, gears, bearings, and other moving parts by
dirt and wear metal particles, air bubbles, and free water
accelerating wear and erosion.
droplets.
5.4 Particle count results can be used to aid in assessing the
3.1.7 ISO Codes, n—a standard classification for coding the
capability of the filtration system responsible for cleaning the
level of contamination by solid particles.
fluid, determining if off-line recirculating filtration is needed to
3.1.7.1 Discussion—This code simplifies the reporting of
clean up the fluid system, or aiding in the decision of whether
particle count data by converting the number of particles per
or not a fluid change is required.
mL into three classes covering ≥4µm , ≥6µm and
(c) (c)
5.5 To accurately measure hard particle contamination
≥14 µm . ISO 4406 classifications are used as an option to
(c)
levels, it is necessary to negate the particle counts contributed
report results for this test method.
by the presence of small levels of free water. This method
3.1.8 particle size, µm ,n—diameter of a circle with an
(c) includes a process by which this can be accomplished using a
area equivalent to the projected area of a particle passing
water-masking diluent technique whereby water droplets of a
through the detecting cell in accordance with ISO 11171.
size below the target level are finely distributed.
3.1.9 particle size cumulative count, n—total number of
5.6 Certain additives or additive by-products that are semi-
particles with sizes greater than a specified particle size (for
insoluble or insoluble in oil, namely the polydimethylsiloxane
example, ≥4µm , ≥6µm , ≥10 µm , ≥14 µm ,
(c) (c) (c) (c)
defoamant additive and oxidation by-products, are known to
≥21 µm , ≥38 µm , etc.).
(c) (c) cause light scattering in automatic particle counters, which in
turn causes falsely high counts.These and similar materials are
NOTE 3—All particle counts are expressed on per 1 mL basis.
commonly termed “soft particles” (see 3.1.6) and are not
3.1.10 soot-in-oil, n—a sub-micron particulate product of
known to directly increase wear and erosion within an operat-
incomplete combustion commonly found in in-service diesel
ing system. The contribution of these particles to the particle
engine crankcase oil.
size cumulative count is negated with this method.
3.1.11 water-masking diluent, n—a particular kind of di-
5.7 The use of dilution in this test method counteracts
luent capable of dissolving otherwise immiscible substances
viscosity effects for highly viscous oils that impact the accu-
such as water or soft particles in the sample lubricant or
racy of automatic optical particle counting results.
hydraulic fluid. See Annex A1, Table A1.1.
6. Interferences
4. Summary of Test Method NOTE 4—This section is consistent with the interferences described in
Test Method D6786.
4.1 Inspect sample.
6.1 Dirty environmental conditions and poor handling tech-
4.2 Agitate sample.
niques can easily contaminate the sample or test specimen, or
4.3 Obtainaliquotfromhomogeneoussampleifnotdiluting both.Careshallbetakentoensuretestresultsarenotbiasedby
in original container. introduced particles.
D7647 − 10 (2018)
6.2 Air bubbles in the oil may be counted as particles giving 7.3 Mechanical Shaker, paint shaker, table shaker, or other
false positive readings. Mixing or agitating the sample intro- mechanical device to vigorously agitate sample containers.
duces bubbles into the oil, but these readily dissipate with 2 2
7.4 Ultrasonic Bath, rated at 3000 W⁄m to 10 000 W⁄m .
sonication or vacuum degassing.
This bath aids in the removal of air bubbles generated in the
6.3 Suspended or free water in the oil will generally be sample during the agitation process while also working to
counted as particles. suspend particles in the sample and slow the settling process.
NOTE 5—Free or emulsified water interference presented can be
7.5 Liquid Dispensers, fitted with 0.8 µm or finer filter.
negated by using the water-masking diluent as described in this test
method.
7.6 Volumetric Pipette and Bulb, if volumetric dilution or
fluid transfer with a pipette is desired. Pipettes made of
6.4 Excessive concentrations of particles in the oil will
graduated glass or disposable polyethylene. Any glassware
cause coincidence or electronic saturation errors, or both.
used shall be cleaned and verified in accordance with ISO
LimitsaredeterminedbyISO11171andaregenerallysupplied
3722.
by the instrument manufacturer. These errors may be avoided
by increasing the dilution ratio with the diluent used in this test
7.7 Density Meter, with an accuracy of 0.01 g⁄cm,ifthe
method.
mass dilution method is used.
6.5 Odd-shaped particles and fibers may be classified with
7.8 Filter Apparatus, for filtering the diluent. There is no
incorrect calculated particle size, depending on their orienta-
requirement for the apparatus itself but it shall be capable of
tion as they pass through the sensing zone of the instrument.
producing acceptably clean diluent as necessary. Take appro-
priate safety precautions in handling low flash materials.
6.6 Dye-in-oil is used by some lubricant manufacturers to
distinguish certain lubricant types or brands. It is unusual for
7.9 Vacuum Degassing Apparatus, capable of pulling full
that dye to have a discernible impact on particle count data.
vacuum on the sample container in a vacuum chamber (per
Nonetheless, it is worthwhile to evaluate possible interferences
12.4.1) or syringe degassing port (per 12.4.3) within time limit
for dye-in-oil by testing a sample of filtered, dyed, lubricant. If
specified.
the automatic particle counter yields unusual results or if it
7.10 Glassware, any glassware used shall be cleaned and
reports an optical warning message, then this may be an
verified in accordance with ISO 3722.
indication of this type of interference.
7.11 Sample Container, a container used for collecting the
6.7 Excessive soot-in-oil is an interference that makes it
neat sample per 9.1 and 9.2, or for diluting sample specimens.
impractical to test in-service diesel engine lubricants, espe-
7.11.1 Sample containers shall not be reused.
cially when soot level exceeds 1 %. This is not normally a
7.11.2 Recommended containers are cylindrical specimen
problem for natural gas and gasoline engine oils. However
bottles (or jars) typically made of polypropylene, polystyrene,
heavy duty diesel engine oils typically produce excessive soot
PET, or glass with nominally flat bottoms, fitted with a suitable
for most automatic particle counters. The coincident, opaque,
non-shedding threaded cap.
soot particles reduce light transmission and produce very high
7.11.3 The dimensions and capacity of sample containers
false particle counts.
depends on specimen requirements and APC design. Sample
6.8 Solid lubricants, such as molybdenum disulfide or
containers often have an approximate capacity of 125 mL.
graphite are used in some lubricating oils, especially for
However individual specimen requirements and APC design
extreme pressure applications. These materials are typically
may call for substantially smaller or much larger sample
used at levels high enough to render the fluid opaque or to
containers.
cause coincidence errors due to high particle concentrations in
7.11.4 After performing any cleaning procedures, the
the detector. Even if these factors can be overcome with
sample containers shall meet the cleanliness criteria of contrib-
sufficient dilution, increases in particle counts are difficult to
uting less than 1 % of the total particles expected in the
determine with adequate precision due to the inherently high
cleanest sample.
particle counts in these fluids.
7.11.5 Sample containers shall be comp
...
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: D7647 − 10 (Reapproved 2018)
Standard Test Method for
Automatic Particle Counting of Lubricating and Hydraulic
Fluids Using Dilution Techniques to Eliminate the
Contribution of Water and Interfering Soft Particles by Light
Extinction
This standard is issued under the fixed designation D7647; 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 1.8 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 determination of particle
responsibility of the user of this standard to establish appro-
concentration and particle size distribution in new and in-
priate safety, health, and environmental practices and deter-
service oils used for lubrication and hydraulic purposes.
mine the applicability of regulatory limitations prior to use.
1.2 Particles considered are in the range from 4 µm to
(c) 1.9 This international standard was developed in accor-
200 µm with the upper limit being dependent on the specific
dance with internationally recognized principles on standard-
(c)
automatic particle counter being used.
ization established in the Decision on Principles for the
NOTE 1—For the purpose of this test method, water droplets not masked
Development of International Standards, Guides and Recom-
by the diluent procedure are detected as particles, and agglomerated
mendations issued by the World Trade Organization Technical
particles are detected and reported as a single larger particle.
Barriers to Trade (TBT) Committee.
NOTE 2—The subscript is used to denote that the apparatus has been
(c)
calibrated in accordance with ISO 11171. This subscript strictly only
(c)
applies to particles up to 50 µm. 2. Referenced Documents
2.1 ASTM Standards:
1.3 Lubricants that can be analyzed by this test method are
categorized as petroleum products or synthetic based products, D4057 Practice for Manual Sampling of Petroleum and
Petroleum Products
such as: polyalpha olefin, polyalkylene glycol, or phosphate
ester. Applicable viscosity range is up to 1000 mm /s at 40 °C. D4177 Practice for Automatic Sampling of Petroleum and
Petroleum Products
This procedure may be appropriate for other petroleum and
synthetic based lubricants not included in the precision state- D6786 Test Method for Particle Count in Mineral Insulating
Oil Using Automatic Optical Particle Counters
ment.
2.2 ISO Standards:
1.4 Samples containing visible particles may not be suitable
ISO 3722 Hydraulic fluid power—Fluid sample
for analysis using this test method.
containers—Qualifying and controlling cleaning methods
1.5 Samples that are opaque after dilution are not suitable
ISO 4406 Hydraulic fluid power—Fluids—Method for cod-
for analysis using this test method.
ing level of contamination by solid particles
1.6 The test method is specific to automatic particle coun- ISO 11171 Hydraulic fluid power—Calibration of automatic
ters that use the light extinction principle and are calibrated particle counters for liquids
according to the latest revision of ISO 11171.
3. Terminology
1.7 The values stated in SI units are to be regarded as
3.1 Definitions:
standard. No other units of measurement are included in this
3.1.1 For the purposes of this test method, the following
standard.
definitions apply:
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 D02.96.05 on In-Service Lubricants Particle Counting Practices and contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Techniques. Standards volume information, refer to the standard’s Document Summary page on
Current edition approved April 1, 2018. Published May 2018. Originally the ASTM website.
approved in 2010. Last previous edition approved in 2010 as D7647 – 10. DOI: Available from American National Standards Institute (ANSI), 25 W. 43rd St.,
10.1520/D7647-10R18. 4th Floor, New York, NY 10036, http://www.ansi.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D7647 − 10 (2018)
3.1.2 coincidence, n—the presence of more than one particle 4.4 Dilute with appropriate diluent for the sample type.
in the sensing zone of a particle analyzer at the same time,
4.5 Agitate diluted sample.
causing incorrect sizing and incorrect counting of the particle
4.6 Degas sample.
present. The coincidence limit of the counter is determined by
4.7 Begin testing within 90 s (or repeat agitation and degas-
the maximum acceptable concentration of particles in the
sing).
sensing zone and is supplied by the instrument manufacturer.
Refer to Section 3.4 in ISO 11171.
4.8 Obtain particle counts in triplicate (for sample and
method blank).
3.1.3 diluent, n—a solvent listed in Annex A1, Table A1.1,
having viscosity less than 10 mm /s at 40 °C that is physically
4.9 Analyze data and conduct validity checks.
and chemically compatible with the apparatus used and easily
4.10 Report results.
soluble at room temperature with the sample lubricant or
hydraulic fluid.
5. Significance and Use
3.1.4 emulsified water, n—water that exists in oil between 5.1 This test method is intended for use in analytical
the states of fully dissolved and phase-separated. An emulsi-
laboratories including onsite in-service oil analysis laborato-
fying agent in the oil causes the two immiscible liquids to
ries.
coexist in a heterogeneous mixture.
5.2 Hard particles in lubricating or fluid power systems have
3.1.5 free water, n—water that exists in a separate phase in
a detrimental effect on the system as they cause operating
an oil sample. This occurs when the water content of the oil
components to wear and also accelerate the degradation of the
exceeds the water holding capacity of the oil.
oil. Hard particles in the oil originate from a variety of sources
including generation from within an operating fluid system or
3.1.6 interfering soft particles, n—an undissolved, dispersed
contamination, which may occur during the storage and han-
material (such as an additive) within an oil blend or substance
dling of new oils or via ingress into an operating fluid system.
that is formed during the service life of an oil blend.
3.1.6.1 Discussion—When these substances are present in a
5.3 High levels of contaminants can cause filter blockages
sample and not completely solubilized, they are likely to be
and hard particles can have a serious impact on the life of
counted by an optical particle counter in a similar manner to
pumps, pistons, gears, bearings, and other moving parts by
dirt and wear metal particles, air bubbles, and free water
accelerating wear and erosion.
droplets.
5.4 Particle count results can be used to aid in assessing the
3.1.7 ISO Codes, n—a standard classification for coding the
capability of the filtration system responsible for cleaning the
level of contamination by solid particles.
fluid, determining if off-line recirculating filtration is needed to
3.1.7.1 Discussion—This code simplifies the reporting of
clean up the fluid system, or aiding in the decision of whether
particle count data by converting the number of particles per
or not a fluid change is required.
mL into three classes covering ≥4 µm , ≥6 µm and
(c) (c)
5.5 To accurately measure hard particle contamination
≥14 µm . ISO 4406 classifications are used as an option to
(c)
levels, it is necessary to negate the particle counts contributed
report results for this test method.
by the presence of small levels of free water. This method
3.1.8 particle size, µm , n—diameter of a circle with an
(c) includes a process by which this can be accomplished using a
area equivalent to the projected area of a particle passing
water-masking diluent technique whereby water droplets of a
through the detecting cell in accordance with ISO 11171.
size below the target level are finely distributed.
3.1.9 particle size cumulative count, n—total number of
5.6 Certain additives or additive by-products that are semi-
particles with sizes greater than a specified particle size (for
insoluble or insoluble in oil, namely the polydimethylsiloxane
example, ≥4 µm , ≥6 µm , ≥10 µm , ≥14 µm ,
(c) (c) (c) (c) defoamant additive and oxidation by-products, are known to
≥21 µm , ≥38 µm , etc.).
(c) (c)
cause light scattering in automatic particle counters, which in
turn causes falsely high counts. These and similar materials are
NOTE 3—All particle counts are expressed on per 1 mL basis.
commonly termed “soft particles” (see 3.1.6) and are not
3.1.10 soot-in-oil, n—a sub-micron particulate product of
known to directly increase wear and erosion within an operat-
incomplete combustion commonly found in in-service diesel
ing system. The contribution of these particles to the particle
engine crankcase oil.
size cumulative count is negated with this method.
3.1.11 water-masking diluent, n—a particular kind of di-
5.7 The use of dilution in this test method counteracts
luent capable of dissolving otherwise immiscible substances
viscosity effects for highly viscous oils that impact the accu-
such as water or soft particles in the sample lubricant or
racy of automatic optical particle counting results.
hydraulic fluid. See Annex A1, Table A1.1.
6. Interferences
4. Summary of Test Method
NOTE 4—This section is consistent with the interferences described in
Test Method D6786.
4.1 Inspect sample.
6.1 Dirty environmental conditions and poor handling tech-
4.2 Agitate sample.
niques can easily contaminate the sample or test specimen, or
4.3 Obtain aliquot from homogeneous sample if not diluting both. Care shall be taken to ensure test results are not biased by
in original container. introduced particles.
D7647 − 10 (2018)
6.2 Air bubbles in the oil may be counted as particles giving 7.3 Mechanical Shaker, paint shaker, table shaker, or other
false positive readings. Mixing or agitating the sample intro- mechanical device to vigorously agitate sample containers.
duces bubbles into the oil, but these readily dissipate with 2 2
7.4 Ultrasonic Bath, rated at 3000 W ⁄m to 10 000 W ⁄m .
sonication or vacuum degassing.
This bath aids in the removal of air bubbles generated in the
6.3 Suspended or free water in the oil will generally be sample during the agitation process while also working to
counted as particles. suspend particles in the sample and slow the settling process.
NOTE 5—Free or emulsified water interference presented can be
7.5 Liquid Dispensers, fitted with 0.8 µm or finer filter.
negated by using the water-masking diluent as described in this test
method.
7.6 Volumetric Pipette and Bulb, if volumetric dilution or
fluid transfer with a pipette is desired. Pipettes made of
6.4 Excessive concentrations of particles in the oil will
graduated glass or disposable polyethylene. Any glassware
cause coincidence or electronic saturation errors, or both.
used shall be cleaned and verified in accordance with ISO
Limits are determined by ISO 11171 and are generally supplied
3722.
by the instrument manufacturer. These errors may be avoided
by increasing the dilution ratio with the diluent used in this test
7.7 Density Meter, with an accuracy of 0.01 g ⁄cm , if the
method.
mass dilution method is used.
6.5 Odd-shaped particles and fibers may be classified with
7.8 Filter Apparatus, for filtering the diluent. There is no
incorrect calculated particle size, depending on their orienta-
requirement for the apparatus itself but it shall be capable of
tion as they pass through the sensing zone of the instrument.
producing acceptably clean diluent as necessary. Take appro-
priate safety precautions in handling low flash materials.
6.6 Dye-in-oil is used by some lubricant manufacturers to
distinguish certain lubricant types or brands. It is unusual for
7.9 Vacuum Degassing Apparatus, capable of pulling full
that dye to have a discernible impact on particle count data.
vacuum on the sample container in a vacuum chamber (per
Nonetheless, it is worthwhile to evaluate possible interferences
12.4.1) or syringe degassing port (per 12.4.3) within time limit
for dye-in-oil by testing a sample of filtered, dyed, lubricant. If
specified.
the automatic particle counter yields unusual results or if it
7.10 Glassware, any glassware used shall be cleaned and
reports an optical warning message, then this may be an
verified in accordance with ISO 3722.
indication of this type of interference.
7.11 Sample Container, a container used for collecting the
6.7 Excessive soot-in-oil is an interference that makes it
neat sample per 9.1 and 9.2, or for diluting sample specimens.
impractical to test in-service diesel engine lubricants, espe-
7.11.1 Sample containers shall not be reused.
cially when soot level exceeds 1 %. This is not normally a
7.11.2 Recommended containers are cylindrical specimen
problem for natural gas and gasoline engine oils. However
bottles (or jars) typically made of polypropylene, polystyrene,
heavy duty diesel engine oils typically produce excessive soot
PET, or glass with nominally flat bottoms, fitted with a suitable
for most automatic particle counters. The coincident, opaque,
non-shedding threaded cap.
soot particles reduce light transmission and produce very high
7.11.3 The dimensions and capacity of sample containers
false particle counts.
depends on specimen requirements and APC design. Sample
6.8 Solid lubricants, such as molybdenum disulfide or
containers often have an approximate capacity of 125 mL.
graphite are used in some lubricating oils, especially for
However individual specimen requirements and APC design
extreme pressure applications. These materials are typically
may call for substantially smaller or much larger sample
used at levels high enough to render the fluid opaque or to
containers.
cause coincidence errors due to high particle concentrations in
7.11.4 After performing any cleaning procedures, the
the detector. Even if these factors can be overcome with
sample containers shall meet the cleanliness criteria of contrib-
sufficient dilution, increases in particle counts are difficult to
uting less than 1 % of the total particles expected in the
determine with adequate precision due to the inherently high
cleanest sample.
particle counts in these fluids.
7.11.5 Sample containers shall be compatible with fluid and
able to withstand the
...
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: D7647 − 10 D7647 − 10 (Reapproved 2018)
Standard Test Method for
Automatic Particle Counting of Lubricating and Hydraulic
Fluids Using Dilution Techniques to Eliminate the
Contribution of Water and Interfering Soft Particles by Light
Extinction
This standard is issued under the fixed designation D7647; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope
1.1 This test method covers the determination of particle concentration and particle size distribution in new and in-service oils
used for lubrication and hydraulic purposes.
1.2 Particles considered are in the range from 4 μm 4 μm to 200 μm 200 μm with the upper limit being dependent on the
(c) (c)
specific automatic particle counter being used.
NOTE 1—For the purpose of this test method, water droplets not masked by the diluent procedure are detected as particles, and agglomerated particles
are detected and reported as a single larger particle.
NOTE 2—The subscript is used to denote that the apparatus has been calibrated in accordance with ISO 11171. This subscript strictly only applies
(c) (c)
to particles up to 50 μm.50 μm.
1.3 Lubricants that can be analyzed by this test method are categorized as petroleum products or synthetic based products, such
as: polyalpha olefin, polyalkylene glycol, or phosphate ester. Applicable viscosity range is up to 1000 mm1000 mm /s @ 40°C.at
40 °C. This procedure may be appropriate for other petroleum and synthetic based lubricants not included in the precision
statement.
1.4 Samples containing visible particles may not be suitable for analysis using this test method.
1.5 Samples that are opaque after dilution are not suitable for analysis using this test method.
1.6 The test method is specific to automatic particle counters that use the light extinction principle and are calibrated according
to the latest revision of ISO 11171.
1.7 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.8 This test method 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.
1.9 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:
D4057 Practice for Manual Sampling of Petroleum and Petroleum Products
D4177 Practice for Automatic Sampling of Petroleum and Petroleum Products
D6786 Test Method for Particle Count in Mineral Insulating Oil Using Automatic Optical Particle Counters
2.2 ISO Standards:
ISO 3722 Hydraulic Fluid Power–Fluid Sample Containers –Qualifying and Controlling Cleaning Methodsfluid power—Fluid
sample containers—Qualifying and controlling cleaning methods
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 D02.96.05 on In-Service Lubricants Particle Counting Practices and Techniques.
Current edition approved July 1, 2010April 1, 2018. Published September 2010May 2018. Originally approved in 2010. Last previous edition approved in 2010 as
D7647 – 10. DOI: 10.1520/D7647–10.10.1520/D7647-10R18.
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.
Available from American National Standards Institute (ANSI), 25 W. 43rd St., 4th Floor, New York, NY 10036, http://www.ansi.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D7647 − 10 (2018)
ISO 4406 Hydraulic Fluid Power–Fluids–Method for Coding Level of Contamination by Solid Particlesfluid power—Fluids—
Method for coding level of contamination by solid particles
ISO 11171 Hydraulic Fluid Power–Calibration of Automatic Particle Counters for Liquidsfluid power—Calibration of automatic
particle counters for liquids
3. Terminology
3.1 Definitions:
3.1.1 For the purposes of this test method, the following definitions apply:
3.1.2 coincidence, n—the presence of more than one particle in the sensing zone of a particle analyzer at the same time, causing
incorrect sizing and incorrect counting of the particle present. The coincidence limit of the counter is determined by the maximum
acceptable concentration of particles in the sensing zone and is supplied by the instrument manufacturer. Refer to Section 3.4 in
ISO 11171.
3.1.3 diluent, n—a solvent listed in Annex A1, Table A1.1, having viscosity less than 10 mm10 mm /s at 40°C40 °C that is
physically and chemically compatible with the apparatus used and easily soluble at room temperature with the sample lubricant
or hydraulic fluid.
3.1.4 emulsified water, n—water that exists in oil between the states of fully dissolved and phase-separated. An emulsifying
agent in the oil causes the two immiscible liquids to coexist in a heterogeneous mixture.
3.1.5 free water, n—water that exists in a separate phase in an oil sample. This occurs when the water content of the oil exceeds
the water holding capacity of the oil.
3.1.6 interfering soft particles, n—an undissolved, dispersed material (such as an additive) within an oil blend or substance that
is formed during the service life of an oil blend.
3.1.6.1 Discussion—
When these substances are present in a sample and not completely solubilized, they are likely to be counted by an optical particle
counter in a similar manner to dirt and wear metal particles, air bubbles, and free water droplets.
3.1.7 ISO Codes, n—a standard classification for coding the level of contamination by solid particles.
3.1.7.1 Discussion—
This code simplifies the reporting of particle count data by converting the number of particles per mL into three classes covering
≥4 μm ≥4 μm , ≥6 μm ≥6 μm and ≥14 μm ≥14 μm . ISO 4406 classifications are used as an option to report results for this
(c) (c) (c)
test method.
3.1.8 particle size, μm , n—diameter of a circle with an area equivalent to the projected area of a particle passing through the
(c)
detecting cell in accordance with ISO 11171.
3.1.9 particle size cumulative count, n—total number of particles with sizes greater than a specified particle size (for example,
≥4 μm ≥4 μm , ≥6 μm ≥6 μm , ≥10 μm ≥10 μm , ≥14 μm ≥14 μm , ≥21 μm ≥21 μm , ≥38 μm ≥38 μm , etc.).
(c) (c) (c) (c) (c) (c)
NOTE 3—All particle counts are expressed on per 1 mL 1 mL basis.
3.1.10 soot-in-oil, n—a sub-micron particulate product of incomplete combustion commonly found in in-service diesel engine
crankcase oil.
3.1.11 water-masking diluent, n—a particular kind of diluent capable of dissolving otherwise immiscible substances such as
water or soft particles in the sample lubricant or hydraulic fluid. See Annex A1, Table A1.1.
4. Summary of Test Method
4.1 Inspect sample.
4.2 Agitate sample.
4.3 Obtain aliquot from homogeneous sample if not diluting in original container.
4.4 Dilute with appropriate diluent for the sample type.
4.5 Agitate diluted sample.
4.6 Degas sample.
4.7 Begin testing within 90 s 90 s (or repeat agitation and degassing).
4.8 Obtain particle counts in triplicate (for sample and method blank).
D7647 − 10 (2018)
4.9 Analyze data and conduct validity checks.
4.10 Report results.
5. Significance and Use
5.1 This test method is intended for use in analytical laboratories including onsite in-service oil analysis laboratories.
5.2 Hard particles in lubricating or fluid power systems have a detrimental effect on the system as they cause operating
components to wear and also accelerate the degradation of the oil. Hard particles in the oil originate from a variety of sources
including generation from within an operating fluid system or contamination, which may occur during the storage and handling
of new oils or via ingress into an operating fluid system.
5.3 High levels of contaminants can cause filter blockages and hard particles can have a serious impact on the life of pumps,
pistons, gears, bearings, and other moving parts by accelerating wear and erosion.
5.4 Particle count results can be used to aid in assessing the capability of the filtration system responsible for cleaning the fluid,
determining if off-line recirculating filtration is needed to clean up the fluid system, or aiding in the decision of whether or not a
fluid change is required.
5.5 To accurately measure hard particle contamination levels, it is necessary to negate the particle counts contributed by the
presence of small levels of free water. This method includes a process by which this can be accomplished using a water-masking
diluent technique whereby water droplets of a size below the target level are finely distributed.
5.6 Certain additives or additive by-products that are semi-insoluble or insoluble in oil, namely the polydimethylsiloxane
defoamant additive and oxidation by-products, are known to cause light scattering in automatic particle counters, which in turn
causes falsely high counts. These and similar materials are commonly termed “soft particles” (see 3.1.6) and are not known to
directly increase wear and erosion within an operating system. The contribution of these particles to the particle size cumulative
count is negated with this method.
5.7 The use of dilution in this test method counteracts viscosity effects for highly viscous oils that impact the accuracy of
automatic optical particle counting results.
6. Interferences
NOTE 4—This section is consistent with the interferences described in Test Method D6786.
6.1 Dirty environmental conditions and poor handling techniques can easily contaminate the sample or test specimen, or both.
Care shall be taken to ensure test results are not biased by introduced particles.
6.2 Air bubbles in the oil may be counted as particles giving false positive readings. Mixing or agitating the sample introduces
bubbles into the oil, but these readily dissipate with sonication or vacuum degassing.
6.3 Suspended or free water in the oil will generally be counted as particles.
NOTE 5—Free or emulsified water interference presented can be negated by using the water-masking diluent as described in this test method.
6.4 Excessive concentrations of particles in the oil will cause coincidence or electronic saturation errors, or both. Limits are
determined by ISO 11171 and are generally supplied by the instrument manufacturer. These errors may be avoided by increasing
the dilution ratio with the diluent used in this test method.
6.5 Odd-shaped particles and fibers may be classified with incorrect calculated particle size, depending on their orientation as
they pass through the sensing zone of the instrument.
6.6 Dye-in-oil is used by some lubricant manufacturers to distinguish certain lubricant types or brands. It is unusual for that dye
to have a discernible impact on particle count data. Nonetheless, it is worthwhile to evaluate possible interferences for dye-in-oil
by testing a sample of filtered, dyed, lubricant. If the automatic particle counter yields unusual results or if it reports an optical
warning message, then this may be an indication of this type of interference.
6.7 Excessive soot-in-oil is an interference that makes it impractical to test in-service diesel engine lubricants, especially when
soot level exceeds 1 %. This is not normally a problem for natural gas and gasoline engine oils. However heavy duty diesel engine
oils typically produce excessive soot for most automatic particle counters. The coincident, opaque, soot particles reduce light
transmission and produce very high false particle counts.
6.8 Solid lubricants, such as molybdenum disulfide or graphite are used in some lubricating oils, especially for extreme pressure
applications. These materials are typically used at levels high enough to render the fluid opaque or to cause coincidence errors due
to high particle concentrations in the detector. Even if these factors can be overcome with sufficient dilution, increases in particle
counts are difficult to determine with adequate precision due to the inherently high particle counts in these fluids.
6.9 Specimen bottles shall not be reused. This is a source of cross-contamination interference.
D7647 − 10 (2018)
7. Apparatus
7.1 Liquid Automatic Particle Counter (APC), liquid optical particle counter based on the light extinction principle. The
instrument shall be capable of recording the size and number of particles as they pass across the detector. The particle counter shall
include a sampling apparatus that automatically delivers a predetermined volume of specimen at a controlled flow rate to the
sensing zone of the analyzer.
7.2 Analytical Balance, for mass dilution, calibrated, with a resolution of 100 mg.100 mg.
7.3 Mechanical Shaker, paint shaker, table shaker, or other mechanical device to vigorously agitate sample containers.
2 2
7.4 Ultrasonic Bath, rated at 30003000 W ⁄m to 10 000 10 000 W W/m⁄m . This bath aids in the removal of air bubbles
generated in the sample during the agitation process while also working to suspend particles in the sample and slow the settling
process.
7.5 Liquid Dispensers, fitted with 0.8 μm 0.8 μm or finer filter.
7.6 Volumetric Pipette and Bulb, if volumetric dilution or fluid transfer with a pipette is desired. Pipettes made of graduated
glass or disposable polyethylene. Any glassware used shall be cleaned and verified in accordance with ISO 3722.
7.7 Density Meter, with an accuracy of 0.01 0.01 g g/cm⁄cm , if the mass dilution method is used.
7.8 Filter Apparatus, for filtering the diluent. There is no requirement for the apparatus itself but it shall be capable of producing
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.