ASTM D7718-11(2019)
(Practice)Standard Practice for Obtaining In-Service Samples of Lubricating Grease
Standard Practice for Obtaining In-Service Samples of Lubricating Grease
SIGNIFICANCE AND USE
4.1 This practice is typically used to obtain in-service lubricating grease samples from machinery.
4.2 In this practice, a consistent and repeatable method is outlined for obtaining trendable samples from the following applications including motor-operated valves, gearboxes, pillow-block bearings, electric motors, exposed bearings, open gears, or failed grease-lubricated components. This allows for analysis and inspection of in-service lubricating grease that aids in predicting the life and condition of the grease-lubricated component. This information can be combined with other technologies such as infrared imaging, vibration analysis, and ultrasonic vibration analysis to predict when a machine may fail. The knowledge gained by the aforementioned analyses, in addition to the knowledge gained from the in-service lubricating grease analysis and inspection, may allow for more overall uptime by aiding in the prediction of grease-lubricated component failures as part of a predictive maintenance schedule. The prediction of a failing grease-lubricated component will also improve the level of safety of all who work around the component.
SCOPE
1.1 This practice covers the method to obtain a trendable in-service lubricating grease sample from the following configurations including motor-operated valves, gearboxes, pillow-block bearings, electric motors, exposed bearings, open gears, or failed grease-lubricated components.
1.2 In some cases, it may be necessary to take more than one sample from a piece of equipment to obtain more trendable results. Examples of this could be a large bearing that does not fully rotate, such as a slew bearing, or one in which sufficient mixing does not otherwise occur.
1.3 Samples taken in the above manner may need to be mixed to form a more homogeneous sample. This may also be true of other samples such as those taken from open face bearings.
1.4 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only. The exception to this is a standard English units thread for which there is no metric equivalent.
Note 1: The standard pipe thread referred to is the national pipe thread tapered thread.
1.5 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.
1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
General Information
Relations
Standards Content (Sample)
This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: D7718 − 11 (Reapproved 2019)
Standard Practice for
Obtaining In-Service Samples of Lubricating Grease
This standard is issued under the fixed designation D7718; 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 2. Referenced Documents
1.1 This practice covers the method to obtain a trendable 2.1 ASTM Standards:
in-service lubricating grease sample from the following con- D217 Test Methods for Cone Penetration of Lubricating
figurations including motor-operated valves, gearboxes, Grease
pillow-block bearings, electric motors, exposed bearings, open D4057 Practice for Manual Sampling of Petroleum and
gears, or failed grease-lubricated components. Petroleum Products
2.2 ANSI/ASME Standard:
1.2 Insomecases,itmaybenecessarytotakemorethanone
B1.20.1 Pipe Threads, General Purpose (Inch)
sample from a piece of equipment to obtain more trendable
results. Examples of this could be a large bearing that does not
3. Terminology
fully rotate, such as a slew bearing, or one in which sufficient
mixing does not otherwise occur.
3.1 Definitions:
3.1.1 active grease-sampling device, n—device designed to
1.3 Samples taken in the above manner may need to be
take an active sample of a lubricating grease from a bearing,
mixed to form a more homogeneous sample. This may also be
gear, or drive shaft located in a grease-lubricated component.
true of other samples such as those taken from open face
bearings. 3.1.2 active sampling, v—to use a sampling device to
actively gather an in-service lubricating grease sample from a
1.4 The values stated in SI units are to be regarded as the
grease-lubricated component.
standard. The values given in parentheses are for information
3.1.3 actuate, v—to hold the interior cylinder of the active
only.TheexceptiontothisisastandardEnglishunitsthreadfor
grease-sampling device while pushing the exterior cylinder
which there is no metric equivalent.
forward toward the grease-lubricated component that is being
NOTE1—Thestandardpipethreadreferredtoisthenationalpipethread
sampledallowinglubricatinggreasetofillthesamplingdevice.
tapered thread.
3.1.4 extension rod, n—tool used to extend the depth at
1.5 This standard does not purport to address all of the
which a sample is taken with an active grease-sampling device.
safety concerns, if any, associated with its use. It is the
3.1.4.1 Discussion—The extension rod may also be used to
responsibility of the user of this standard to establish appro-
remotely actuate an active grease-sampling device.
priate safety, health, and environmental practices and deter-
mine the applicability of regulatory limitations prior to use. 3.1.5 in-service lubricating grease, n—lubricating grease
1.6 This international standard was developed in accor-
that has been applied as a lubricant to a gear, bearing, or drive
dance with internationally recognized principles on standard- screw for any period of time.
ization established in the Decision on Principles for the
3.1.6 lubricating grease, n—semi-fluid to solid product of a
Development of International Standards, Guides and Recom-
dispersion of a thickener in a liquid lubricant.
mendations issued by the World Trade Organization Technical
3.1.6.1 Discussion—The dispersion of the thickener forms a
Barriers to Trade (TBT) Committee.
two-phase system and immobilizes the liquid lubricant by
1 2
This practice is under the jurisdiction of ASTM Committee D02 on Petroleum For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Products, Liquid Fuels, and Lubricants and is the direct responsibility of Subcom- contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
mittee D02.96.04 on Guidelines for In-Services Lubricants Analysis. Standards volume information, refer to the standard’s Document Summary page on
CurrenteditionapprovedMay1,2019.PublishedJuly2019.Originallyapproved the ASTM website.
in 2011. Last previous edition approved in 2011 as D7718 – 11. Available from American National Standards Institute (ANSI), 25 W. 43rd St.,
DOI:10.1520 ⁄D7718-11R19. 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
D7718 − 11 (2019)
surface tension and other physical forces. Other ingredients are can be quite fragile if dropped. All glass containers shall be
commonly included to impart special properties. D217 visually inspected for dust, dirt, and other contaminants that
could affect subsequent analysis results.
3.1.7 passive grease-sampling device, n—device designed
5.1.3 Metal Cans—A metal sample container may be used,
to gather a sample from the equipment by being attached to the
but reactions can occur between the sample and the container.
grease reservoir at the purge point.
The most common reaction is oxidation (rusting) of the
3.1.7.1 Discussion—This device has also been designed to
container. If a metal container is to be used, make sure that it
contain a lubricating grease sample that has been gathered with
will not react with the sample and will not easily oxidize (rust).
other methods.
An example of such a container would be a stainless steel
3.1.8 passive sampling, v—to use a passive grease-sampling
container. All metal cans shall be visually inspected for dust,
device to collect a purged sample of in-service lubricating
dirt, and other contaminants that could affect subsequent
grease from a purge path.
analysis results.
3.1.9 trendable, adj—sample of in-service lubricating
5.2 Sampling Devices—The sampling devices for each pro-
grease used to trend the physical properties, wear levels, and
cedure are described in detail in each specific procedure. In
contaminants in a grease-lubricated component.
general, all sampling devices shall be clean, dry, and free of
anydirt,dust,orothercontaminantsthatcouldaffecttheresults
4. Significance and Use
of subsequent analysis.
4.1 This practice is typically used to obtain in-service
6. Hazards
lubricating grease samples from machinery.
6.1 When sampling from any component, it is up to the staff
4.2 In this practice, a consistent and repeatable method is
of the facility to determine the safest possible way to obtain the
outlined for obtaining trendable samples from the following
sample.
applications including motor-operated valves, gearboxes,
pillow-block bearings, electric motors, exposed bearings, open
6.2 Unless sampling from a purge path, a sampling device
gears, or failed grease-lubricated components. This allows for
should not be put into or onto a grease-lubricated component
analysis and inspection of in-service lubricating grease that
while it is running. This could cause both the component and
aidsinpredictingthelifeandconditionofthegrease-lubricated
the sampling device to be damaged.
component. This information can be combined with other
6.3 It is assumed that the person who is taking the sample is
technologies such as infrared imaging, vibration analysis, and
trained in all of the necessary safety precautions for working
ultrasonic vibration analysis to predict when a machine may
with the equipment.
fail. The knowledge gained by the aforementioned analyses, in
addition to the knowledge gained from the in-service lubricat- 6.4 It is important the person who is obtaining the samples
follows all cleanliness guidelines outlined by the facility. The
ing grease analysis and inspection, may allow for more overall
uptime by aiding in the prediction of grease-lubricated com- operator should wear any required personal protection equip-
ment (PPE). In addition, the operator should also wear latex or
ponent failures as part of a predictive maintenance schedule.
The prediction of a failing grease-lubricated component will nitrile gloves unless the current PPE requirements meet or
exceed this requirement. Gloves worn should be clean at the
also improve the level of safety of all who work around the
component. time that the sample is taken.
7. General Sampling Procedures, Limitations, and
5. Apparatus
Considerations
5.1 Sample Containers—Commercially available in many
7.1 Equipment Cleanliness—The area around the access
shapes, sizes, materials, and configurations. The appropriate
port of all components to be sampled shall first be cleansed of
sample container can only be selected once the operator knows
dust, dirt, and other contaminants. The sampling devices and
the specific application for the sample being taken. The
containers shall also be clean, dry, and free of any dust, dirt,
operator shall be sure that the material of the container will not
and other contaminants that can affect the results of any
interact with the material being sampled. The operator shall
subsequent analysis performed on the sample.
also ensure that the proper size container is selected so it can
house enough material so all of the intended subsequent 7.2 Homogeneity of Samples—When sampling lubricating
laboratory analysis and inspections can be run on the sample. greases, it is important to keep in mind that the quality and
5.1.1 Bottles (Plastic)—Use a plastic crushproof bottle with trendability of the sample relies a great deal on the sampling
a screw-on cap so the sample contained cannot leak out. All location’s proximity to the component. This is because lubri-
plastic containers shall be visually inspected for dust, dirt, and cating grease does not freely flow and distribute wear particles,
other contaminants that could affect subsequent analysis re- oxidation, and other tested parameters.
sults. The plastic container shall also be made out of a 7.2.1 If the lubricating grease inside of a component is not
nonplasticized plastic such as high-density polyethylene or observably homogenous, it is up to the operator to determine if
ultra-high molecular-weight polyethylene. it is of value to obtain one or multiple samples. If it is
5.1.2 Bottles (Glass)—Use a glass bottle with a screw-on determined that it is of value to obtain different samples from
cap so that the sample contained cannot leak out. One also has the same component as a result of an observable physical
to take special care in dealing with a glass container because it difference in the sample, the operator shall collect the samples
D7718 − 11 (2019)
separately and ensure that they are identified by the sampling 7.9.3 Name of the person responsible for the sample (op-
location and physical appearance characteristics that differen- erator).
tiate them. 7.9.4 Name of baseline lubricating grease.
7.9.5 Sample point identification.
7.3 Sample-Mixing Systems—If a sample is to be mixed
7.9.6 Run hours of the grease lubricated component at the
before the testing of subsamples, it is important to keep this in
time the sample is taken provided the component has a
mind when selecting a sample container.
run-hours meter.
7.4 Sample Container Uniformity—It is also important to
8. Procedure for Active Sampling of a Grease-Lubricated
keep in mind that sample container uniformity is important to
Component
theindividualorlaboratoryresponsibleforperforminganalysis
or inspections. It allows for the individual or laboratory
8.1 Using a Sampling Device:
responsible to streamline their processes, which allows them to
8.1.1 Application—Obtaining an in service sample from a
lower their operating costs. For this reason, the operator should
motor-operated valve, gearbox, electric motor, or other body of
consult the responsible individual or laboratory for their
lubricating grease by use of an active grease sampling device.
suggestions on the sample container size, type, and material.
NOTE 2—When following this procedure, “electric motor” refers to any
electric motor that has a drain plug or access port large enough to allow
7.5 Physical and Chemical Property Tests—The tests to be
an active grease-sampling device into the lubricating grease reservoir and
run on the samples will dictate the amount of sample required
adjacent to the bearing.
and possibly the type of sample container. The amount of
NOTE 3—Various configurations and styles of active grease-sampling
sample required can vary greatly for grease analysis. It is
devices are possible and can be inserted into the grease reservoir. This
recommended that the operator contact the responsible indi- specific procedure addresses a commercially available unit, the Grease
Thief Type II, which has been designed to optimize the process.
vidual or laboratory who will perform the tests to ensure that
they send the required amount of sample.
8.1.2 Apparatus—An active grease-sampling device at-
tached to an extension rod is used to obtain a trendable
7.6 Operator Training—In order to ensure that the sample
in-service lubricating grease sample from a grease-lubricated
integrity is upheld and that the sample is as trendable as
component.
possible the operator shall be trained on how to properly take
8.1.2.1 Active Grease-Sampling Device—Use a cylinder
the sample.This includes an in depth knowledge of the internal
with a ⁄8 in. national pipe thread at either end of a precision
layout of the component, locations of desired sampling points,
bore cylinder. There should be a pair of relief holes at one end
instruction on how to properly use the selected sampling
of the cylinder to allow for purging of excess lubricating
devices, and how to properly clean the locations prior to
grease. Inside of the cylinder is a precision molded piston with
sampling.
a stinger probe the length of the cylinder minus the length of
7.7 General Sampling Procedure—The following proce-
the piston. Also, the piston should have a handle that extends
dures should be followed regardless of which of the below
out the opposite end of the cylinder that allows the piston and
methods are being used to obtain the sample.
probe assembly to be attached to an active grease-sampling
device extension rod. The steps outlined in 8.2.3 cover the use
Sample Handling
of the device in Fig. 1 (ANSI/ASME B1.20.1).
7.8 In-Service Lubricating Grease Samples—The sample
8.1.2.2 Extension Rod (Active Grease-Sampling Device)—
container or the grease-sampling device should always be
Use a thin, hollow cylinder approximately 457 mm (18 in.), or
capped or sealed to prevent contamination. If the in-service
other length, containing a tee handle at one end, which the
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