ASTM D8385-22

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: D8385 − 22
Standard Test Method for
Dry Filterability of Lubricants and Hydraulic Fluids by Mass
Flow Technique
This standard is issued under the fixed designation D8385; 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 D4057 Practice for Manual Sampling of Petroleum and
Petroleum Products
1.1 This test method covers determination of the dry filter-
D4175 Terminology Relating to Petroleum Products, Liquid
ability of lubricants and hydraulic fluids based upon mass flow
Fuels, and Lubricants
rate measurements through a 0.8 µm membrane after ageing
D6300 Practice for Determination of Precision and Bias
(Note 1). The procedure applies to lubricants and hydraulic
Data for Use in Test Methods for Petroleum Products,
fluids that are formulated with American Petroleum Institute
Liquid Fuels, and Lubricants
(API) Group I, II, III, IV, and certain V base stocks. Products
2.2 ISO Standards:
formulated with water or base stocks that are heavier than
ISO 13357 Petroleum products – Determination of the fil-
water are out of scope.
terability of lubricating oils – Part 2: Procedure for dry
NOTE 1—This test method is similar to ISO 13357 but differs from the
oils
ISOmethodinthemannerbywhichfilterabilityisassessed.InISO13357,
ISO 16889 Hydraulic fluid power – Filters – Multi-pass
volume flow rates are used to determine filterability. In this test method,
massflowratesareused.Measurementsoffilterabilitybasedonmassflow method for evaluating filtration performance of a filter
rates facilitate automation and can be less susceptible to operator error.
element
NOTE2—Residualwaterduetoatmosphericconditionsorcontaminants
is in scope for these samples and it is typically low for most in process
3. Terminology
samples.
3.1 Definitions:
1.2 The values stated in SI units are to be regarded as
3.1.1 For definitions of terms used in this test method, refer
standard. No other units of measurement are included in this
to Terminology D4175.
standard.
3.2 Definitions of Terms Specific to This Standard:
1.3 This standard does not purport to address all of the
3.2.1 filterability, n—the ability of lubricants and hydraulic
safety concerns, if any, associated with its use. It is the
fluids to pass through fine filters without plugging them; it is a
responsibility of the user of this standard to establish appro-
dimensionless number that is the ratio between two filtration
priate safety, health, and environmental practices and deter-
rates.
mine the applicability of regulatory limitations prior to use.
3.2.2 Stage I filterability index, n—the ratio, expressed as a
1.4 This international standard was developed in accor-
percentage, between 192 g and the mass of oil filtered in the
dance with internationally recognized principles on standard-
time that 192 g would have theoretically taken, assuming no
ization established in the Decision on Principles for the
plugging of the membrane.
Development of International Standards, Guides and Recom-
mendations issued by the World Trade Organization Technical
3.2.3 Stage II filterability index, n—the ratio, expressed as a
Barriers to Trade (TBT) Committee.
percentage, between the flow rate near the start of filtration,
and the flow rate between 160 g and 240 g of filtered mass.
2. Referenced Documents
NOTE 3—Oils having good Stage I filterability would be unlikely to
2.1 ASTM Standards:
cause filter performance problems in use, unless high efficiency fine
D1193 Specification for Reagent Water
filtration is employed in the equipment. Oils with good Stage II filterabil-
ity would be unlikely to cause filtration problems when high efficiency
This test method is under the jurisdiction of ASTM Committee D02 on
fine filtration is present. High efficiency filters, within the context of this
Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of
method, have a Beta Ratio greater than or equal to 75 at 5 µm as defined
Subcommittee D02.N0 on Hydraulic Fluids.
byISO16889.(β ≥75)ThusfluidsthathavegoodStageIIfilterability
5µm
Current edition approved July 1, 2022. Published August 2022. DOI: 10.1520/
D8385-22.
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 Available from International Organization for Standardization (ISO), ISO
Standards volume information, refer to the standard’s Document Summary page on Central Secretariat, Chemin de Blandonnet 8, CP 401, 1214 Vernier, Geneva,
the ASTM website. Switzerland, https://www.iso.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D8385 − 22
are recommended for hydraulic and lubrication systems that have critical
(6.5)canbeclampedbetweenthesealingsurfacesofthefunnel
cleanliness requirements.
and the base by means of a metal clamp or other suitable
3.3 Symbols: air-tight closure.
3.3.1 F —stage I filterability index, dimensionless
I
6.4 Forceps, spade ended.
3.3.2 F —stage II filterability index, dimensionless
II
6.5 Membrane filters, of mixed cellulose esters, diameter
3.3.3 M—actual mass of oil filtered at T ,g
47 mm and mean pore size of 0.8 µm.
m
3.3.4 T —time corresponding to 8 g of oil filtered, s
8 NOTE 6—Membranes of an equivalent specification to Millipore filter
membranes, catalogue number AAWP 047 have been found satisfactory.
3.3.5 T —time corresponding to 40 g of oil filtered, s
6.6 Oven, controlled at 70 °C 6 2.0 °C.
3.3.6 T —time corresponding to 160 g of oil filtered, s
6.7 Petri dishes, glass type.
3.3.7 T —time corresponding to 240 g of oil filtered, s
6.8 Pressure gauge, dial or digital type, capable of reading
3.3.8 T —theoretical time for 192 g of oil to filter, s
m
the required delivery pressures (see 11.7) 65 kPa.
4. Summary of Test Method
6.9 Top loading balance, with dynamic measurement mode.
Capable of continuously recording 0.1 g mass at 0.1 s incre-
4.1 In this test method the fluid is filtered under specific
ments.
conditions through a membrane of 0.8 µm mean pore diameter,
and the times for the specific filtrate masses are recorded.
7. Reagents and Materials
Filterability indices are calculated from ratios of the mass flow
ratenearthestartofthetest,totheflowrateatlaterstages.The 7.1 Purity of Reagents—Reagent grade chemicals shall be
result of the test is the average of three determined values. used in all tests. Unless otherwise indicated, it is intended that
all reagents shall conform to the specifications of the Commit-
5. Significance and Use tee onAnalytical Reagents of theAmerican Chemical Society,
where such specifications are available. Other grades may be
5.1 Precision equipment and high pressure hydraulic ma-
used, provided it is first ascertained that the reagent is of
chinery require filtered lubricants and fluids to prevent damage
sufficiently high purity to permit its use without lessening the
from the circulation of hard particulate contaminants. Three
accuracy of the determination.
types of particulate contaminants are present in lubricants and
hydraulic fluids: built in contaminants from the machinery 7.2 Compressed air or nitrogen, complete with regulator
system capable of supplying air or nitrogen at nominal pres-
assembly process, generated contaminants from equipment
sures between 50 kPa and 200 kPa.The air or nitrogen shall be
wear, and contaminants that enter from external sources.
dry and filtered.
5.2 The ability of lubricants and hydraulic fluids to retain
7.3 Aliphatic solvent, reagent grade heptanes or 2,2,4-
their filterability is critical for efficient and reliable machine
trimethylpentane are suitable.
performance. Normally, the pressure differential across a filter
will increase gradually as the filter accumulates dirt, sludge,
7.4 Water, conforming to Type 3 of Specification D1193 for
and wear debris. In order to prevent the filter from collapsing,
Reagent Water.
bypass valves in the filter assembly open when the differen
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