ASTM D8277-20

Standard Test Method for Wet Filterability of Lubricants and Hydraulic Fluids by Mass Flow Technique

SIGNIFICANCE AND USE
5.1 Precision equipment and high pressure hydraulic machinery require filtered lubricants and fluids to prevent damage from the circulation of hard particulate contaminants. Three types of particulate contaminants are present in lubricants and hydraulic fluids: built in contaminants from the machinery assembly process, generated contaminants from equipment wear, and contaminants that enter from external sources. Water can also enter machinery lubrication and hydraulic systems through fill ports, defective seals, corroded heat exchangers, and reservoir breathers in the form of rain water, cleaning solutions, process water, metalworking fluids, coolants, and humid air.  
5.2 The ability of lubricants and hydraulic fluids to retain their filterability in the presence of moisture is critical for efficient and reliable machine performance. Normally, the pressure differential across a filter will increase gradually as it accumulates dirt, sludge, and wear debris. In order to prevent the filter from collapsing, bypass valves in the filter assembly open when the differential pressure gets too high. If a filter becomes blocked by additives that precipitate due to the presence of contaminating water, the bypass valve will open. This can lead to a machine shutdown or circulation of damaging particles throughout the machine.
SCOPE
1.1 This test method covers determination of the wet filterability of lubricants and hydraulic fluids based upon mass flow rate measurements through a 0.8 µm membrane after ageing of the fluid in the presence of water. The procedure applies to lubricants and hydraulic fluids that are formulated with American Petroleum Institute (API) Group I, II, III, IV and certain V base stocks. Products formulated with water or base stocks that are heavier than water are out of scope.  
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.3 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.  
1.4 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

• Status: Published
• Publication Date: 29-Feb-2020
• ICS: 75.100 - Lubricants, industrial oils and related products
• Technical Committee: D02 - Petroleum Products, Liquid Fuels, and Lubricants
• Drafting Committee: D02.N0 - Hydraulic Fluids

Relations

• Refers: ASTM D6300-24 - Standard Practice for Determination of Precision and Bias Data for Use in Test Methods for Petroleum Products, Liquid Fuels, and Lubricants
• Effective Date: 01-Mar-2024
• Refers: ASTM D6300-23a - Standard Practice for Determination of Precision and Bias Data for Use in Test Methods for Petroleum Products, Liquid Fuels, and Lubricants
• Effective Date: 01-Dec-2023
• Refers: ASTM D6300-19a - Standard Practice for Determination of Precision and Bias Data for Use in Test Methods for Petroleum Products and Lubricants
• Effective Date: 01-Dec-2019
• Refers: ASTM D1401-18 - Standard Test Method for Water Separability of Petroleum Oils and Synthetic Fluids
• Effective Date: 01-Mar-2018
• Refers: ASTM D6300-16 - Standard Practice for Determination of Precision and Bias Data for Use in Test Methods for Petroleum Products and Lubricants
• Effective Date: 01-Apr-2016
• Refers: ASTM D6300-15 - Standard Practice for Determination of Precision and Bias Data for Use in Test Methods for Petroleum Products and Lubricants
• Effective Date: 01-Jun-2015
• Refers: ASTM D6300-14ae1 - Standard Practice for Determination of Precision and Bias Data for Use in Test Methods for Petroleum Products and Lubricants
• Effective Date: 01-Jun-2014
• Refers: ASTM D6300-14a - Standard Practice for Determination of Precision and Bias Data for Use in Test Methods for Petroleum Products and Lubricants
• Effective Date: 01-Jun-2014
• Refers: ASTM D6300-14 - Standard Practice for Determination of Precision and Bias Data for Use in Test Methods for Petroleum Products and Lubricants
• Effective Date: 01-May-2014
• Refers: ASTM D6300-13a - Standard Practice for Determination of Precision and Bias Data for Use in Test Methods for Petroleum Products and Lubricants
• Effective Date: 01-Dec-2013
• Refers: ASTM D6300-13 - Standard Practice for Determination of Precision and Bias Data for Use in Test Methods for Petroleum Products and Lubricants
• Effective Date: 15-Jul-2013
• Refers: ASTM D1401-12e1 - Standard Test Method for Water Separability of Petroleum Oils and Synthetic Fluids
• Effective Date: 15-May-2012
• Refers: ASTM D4057-06(2011) - Standard Practice for Manual Sampling of Petroleum and Petroleum Products
• Effective Date: 01-Jun-2011
• Refers: ASTM D1401-09 - Standard Test Method for Water Separability of Petroleum Oils and Synthetic Fluids
• Effective Date: 01-Jul-2009
• Refers: ASTM D6300-08 - Standard Practice for Determination of Precision and Bias Data for Use in Test Methods for Petroleum Products and Lubricants
• Effective Date: 15-Dec-2008

Overview

ASTM D8277-20 is an international standard that specifies a test method for evaluating the wet filterability of lubricants and hydraulic fluids using a mass flow technique. Developed by ASTM International, this standard is critical for industries relying on precision equipment and high-pressure hydraulic systems, where the presence of hard particulate contaminants and water can cause operational failures. The method measures how well lubricants and hydraulic fluids can pass through a 0.8 μm membrane after the fluids have been aged in the presence of water, providing a quantitative indication of their filterability under realistic conditions.

Key Topics

• Wet Filterability Measurement: The standard details testing procedures to assess how lubricants and hydraulic fluids behave when exposed to moisture and filtered through fine membranes.
• Contaminant Types: Addresses three primary types of particulate contamination found in hydraulic fluids: built-in (from equipment assembly), generated (from wear), and external (from the environment).
• Water Intrusion: Examines risks of water ingress via fill ports, defective seals, corroded components, or humid environments, which can compromise fluid performance.
• Stage I and II Filterability: Describes the calculation of filterability indices to gauge the extent of filter plugging and performance under increasingly challenging conditions.
• Safety and Applicability: Applies to lubricants and hydraulic fluids based on specific API base stock groups (I-IV and some V) and outlines essential safety, health, and environmental considerations during testing.

Applications

ASTM D8277-20 is significant for a range of practical applications, particularly in sectors where reliable filtration of lubricants and hydraulic fluids is essential for equipment longevity and operational reliability:

• Industrial Hydraulics: Ensures that machinery with high-pressure systems maintains optimal performance by identifying fluids that resist filter blockage in the presence of moisture.
• Automotive and Aerospace Maintenance: Supports maintenance teams in selecting hydraulic and lubrication fluids that minimize the risk of system shutdown or damage due to filter bypass or contamination circulation.
• Manufacturing and Processing Plants: Assists operations where moisture ingress is likely, helping to prevent system failures and expensive downtime.
• Fluid Formulation and Quality Control: Enables manufacturers and formulators to evaluate and improve the filterability properties of their products in a controlled, standardized way.

By providing a reliable and reproducible evaluation of wet filterability, this standard helps users select the right fluids for their machinery and guides manufacturers in product development and quality assurance.

Related Standards

• ASTM D1401: Test method for water separability of petroleum oils and synthetic fluids, referenced for assessing fluid interactions with water.
• ASTM D1193: Specification for reagent water, ensuring consistency in testing procedures.
• ASTM D4057: Practice for manual sampling of petroleum and petroleum products, supporting proper sample collection.
• ISO 13357: International method for filterability of lubricating oils, particularly in the presence of water.
• ASTM D6300: Practice for determining precision and bias in the testing method.

These related standards provide additional context and support for laboratories and industries using ASTM D8277-20 to ensure comprehensive evaluation and compatibility within established quality management systems.

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Keywords: ASTM D8277-20, wet filterability, lubricants, hydraulic fluids, filterability index, particulate contaminants, water tolerance, filtration standards, hydraulic system reliability, lubricant testing.

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: D8277 − 20
Standard Test Method for
Wet Filterability of Lubricants and Hydraulic Fluids by Mass
Flow Technique
This standard is issued under the fixed designation D8277; 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 Data for Use in Test Methods for Petroleum Products and
Lubricants
1.1 This test method covers determination of the wet filter-
2.2 ISO Standards:
ability of lubricants and hydraulic fluids based upon mass flow
ISO 13357 Petroleum products – Determination of the filter-
rate measurements through a 0.8 µm membrane after ageing of
abilityoflubricatingoils – Part1:Procedureforoilsinthe
the fluid in the presence of water. The procedure applies to
presence of water
lubricants and hydraulic fluids that are formulated withAmeri-
can Petroleum Institute (API) Group I, II, III, IV and certain V
3. Terminology
base stocks. Products formulated with water or base stocks that
3.1 Definitions of Terms Specific to This Standard:
are heavier than water are out of scope.
3.1.1 filterability, n—the ability of lubricants and hydraulic
1.2 The values stated in SI units are to be regarded as
fluids to pass through fine filters without plugging them; it is a
standard. No other units of measurement are included in this
dimensionless number that is the ratio between two filtration
standard.
rates.
1.3 This standard does not purport to address all of the
3.1.2 Stage I filterability, n—the ratio, expressed as a
safety concerns, if any, associated with its use. It is the
percentage, between 200 g and the mass of oil filtered in the
responsibility of the user of this standard to establish appro-
time that 200 g would have theoretically taken, assuming no
priate safety, health, and environmental practices and deter-
plugging of the membrane; oils having good Stage I
mine the applicability of regulatory limitations prior to use.
filterability, but only a poor Stage II performance, would be
1.4 This international standard was developed in accor-
unlikelytogiveperformanceproblemsinuse,unlessextremely
dance with internationally recognized principles on standard-
fine system filters are utilized.
ization established in the Decision on Principles for the
3.1.3 Stage II filterability, n—the ratio, expressed as a
Development of International Standards, Guides and Recom-
percentage, between the flow rate near the start of filtration,
mendations issued by the World Trade Organization Technical
and the flow rate between 160 g and 240 g of filtered mass; an
Barriers to Trade (TBT) Committee.
oil with good Stage II filterability would be unlikely to give
filtration problems even in the most extreme conditions or with
2. Referenced Documents
fine (less than 5 µm) filtration present; it would thus be
2.1 ASTM Standards:
suitable for use in more critical hydraulic and lubrication
D1193 Specification for Reagent Water
systems.
D1401 TestMethodforWaterSeparabilityofPetroleumOils
3.2 Symbols:
and Synthetic Fluids
3.2.1 F —Stage I filterability index, dimensionless.
D4057 Practice for Manual Sampling of Petroleum and I
Petroleum Products
3.2.2 F —Stage II filterability index, dimensionless.
II
D6300 Practice for Determination of Precision and Bias
3.2.3 M—actual mass of oil filtered at T ,g.
m
3.2.4 T —time corresponding to 8 g of oil filtered, s.
3.2.5 T —time corresponding to 40 g of oil filtered, s.
This test method is under the jurisdiction of ASTM Committee D02 on
Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of 3.2.6 T —time corresponding to 160 g of oil filtered, s.
Subcommittee D02.N0 on Hydraulic Fluids.
3.2.7 T —time corresponding to 240 g of oil filtered, s.
Current edition approved March 1, 2020. Published March 2020. DOI: 10.1520/
D8277-20.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at [e-mail]. 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, BIBC II, Chemin de Blandonnet 8, CP 401, 1214 Vernier,
the ASTM website. Geneva, Switzerland, http://www.iso.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D8277 − 20
3.2.8 T —theoretical time for 192 g of oil to filter, s. 6.4 Forceps, spade ended.
m
6.5 Membrane Filters, of mixed cellulose esters, diameter
4. Summary of Test Method
47 mm and mean pore size of 0.8 µm.
4.1 In this test method, fluid is treated with water at an
NOTE 3—Membranes of an equivalent specification to Millipore filter
elevatedtemperature,filteredunderspecificconditionsthrough
membranes, catalogue number AAWP 047 have been found satisfactory.
a membrane of 0.8 µm mean pore diameter, and the times for
6.6 Stirring Paddle, made of chromium-plated or stainless
the specific filtrate masses are recorded. Filterabilities are
steel and conforming to the following dimensions:
calculated from ratios of the mass flow rate near the start of the
Length, mm 120 ± 1.5
test to the flow rate at later stages. The result of the test is the
Width, mm 19 ± 0.5
average of three determined values.
Thickness, mm 1.5 ± 0.15
Paddle corner radius of curvature, mm 1.6 max
NOTE 1—ISO 13357 is a volume flow rate based method for measuring
It is mounted on a vertical shaft of similar metal, approxi-
the filterability of hydraulic fluids and lubricants. This standard test
method described herein was developed to provide a mass flow rate based mately 6 mm in diameter, connected to a drive mechanism
method for measuring filterability to reduce operator error and facilitate
which rotates the paddle on its longitudinal axis at 1500 rpm 6
automation.
15 rpm.Theapparatusisofsuchdesignthat,whenthecylinder
is clamped in position and the paddle assembly is lowered into
5. Significance and Use
the cylinder, a positive stop engages and holds the assembly
5.1 Precision equipment and high pressure hydraulic ma-
when the lower edge of the paddles is 6 mm from the bottom
chinery require filtered lubricants and fluids to prevent damage
of the cylinder. During the operation of the cylinder, the center
from the circulation of hard particulate contaminants. Three
of the bottom edge of the paddle shall not deviate more than
types of particulate contaminants are present in lubricants and
1 mm from the axis of rotation. When not in operation, the
hydraulic fluids: built in contaminants from the machinery
paddle assembly can be lifted vertically to clear the top of the
assembly process, generated contaminants from equipment
graduated cylinder. (Warning—Paddle edges may be very
wear, and contaminants that enter from external sources.Water
sharp. Handle with care.) (Warning—Aprotective shield may
can also enter machinery lubrication and hydraulic systems
be used to cover the rotating shaft of the stirrer.)
through fill ports, defective seals, corroded heat exchangers,
NOTE 4—The stirring paddle described above is based upon the
and reservoir breathers in the form of rain water, cleaning
requirements of Test Method D1401.
solutions, process water, metalworking fluids, coolants, and
6.7 Oven, controlled at 70 °C 6 2.0 °C.
humid air.
6.8 Petri Dishes, glass type.
5.2 The ability of lubricants and hydraulic fluids to retain
their filterability in the presence of moisture is critical for 6.9 Pressure Gauge, dial or digital type, capable of reading
the required delivery pressures (see 11.4) 65 kPa.
efficient and reliable machine performance. Normally, the
pressure differential across a filter will increase gradually as it
6.10 Top Loading Balance, with dynamic measurement
accumulates dirt, sludge, and wear debris. In order to prevent
mode. Capable of continuously recording 0.1 g mass at 0.1 s
the filter from collapsing, bypass valves in the filter assembly
increments.
open when the differential pressure gets too high. If a filter
becomes blocked by additives that precipitate due to the
7. Reagents and Materials
presence of contaminating water, the bypass valve will open.
7.1 Purity of Reagents—Reagent grade chemicals shall be
This can lead to a machine shutdown or circulation of
used in all tests. Unless otherwise indicated, it is intended that
damaging particles throughout the machine.
all reagents shall conform to the specifications of the Commit-
tee of Analytical Reagents of the American Chemical Society,
6. Apparatus
where such specifications are available. Other grades may be
6.1 Beaker, 500 mL or other size suitable for collecting the
used, provided it is first ascertained that the reagent of
filtrate.
sufficiently high purity to permit its use without lessening the
accuracy of the determinati
...