ASTM F316-03(2011)

Standard Test Methods for Pore Size Characteristics of Membrane Filters by Bubble Point and Mean Flow Pore Test

SIGNIFICANCE AND USE
This test method may be used to:
Determine the maximum pore size of a filter,
Compare the maximum pore sizes of several filters, and
Determine the effect of various processes such as filtration, coating, or autoclaving on the maximum pore size of a membrane.
Membrane filters have discrete pores from one side to the other of the membrane, similar to capillary, tubes. The bubble point test is based on the principle that a wetting liquid is held in these capillary pores by capillary attraction and surface tension, and the minimum pressure required to force liquid from these pores is a function of pore diameter. The pressure at which a steady stream of bubbles appears in this test is the bubble point pressure. The bubble point test is significant not only for indicating maximum pore size, but may also indicate a damaged membrane, ineffective seals, or a system leak.
The results of this test method should not be used as the sole factor to describe the limiting size for retention of particulate contaminants from fluids. The effective pore size calculated from this test method is based on the premise of capillary pores having circular cross sections, and does not refer to actual particle size retention. See Test Method E128 for additional information.
SCOPE
1.1 These test methods cover the determination of two of the pore size properties of membrane filters with maximum pore sizes from 0.1 to 15.0 μm.
1.2 Test Method A presents a test method for measuring the maximum limiting pore diameter of nonfibrous membranes. The limiting diameter is the diameter of a circle having the same area as the smallest section of a given pore (Fig. 1).
1.3 Test Method B measures the relative abundance of a specified pore size in a membrane, defined in terms of the limiting diameter.
1.4 The analyst should be aware that adequate collaborative data for bias statements as required by Practice D2777 is not provided. See the precision and bias section for details.
1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.6 This standard may involve hazardous materials, operations, and equipment. 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 and health practices and determine the applicability of regulatory limitations prior to use.

General Information

• Status: Historical
• Publication Date: 30-Apr-2011
• ICS: 59.080.70 - Geotextiles
• Technical Committee: D19 - Water
• Drafting Committee: D19.08 - Membranes and Ion Exchange Materials

Relations

• Replaces: ASTM F316-03 - Standard Test Methods for Pore Size Characteristics of Membrane Filters by Bubble Point and Mean Flow Pore Test
• Effective Date: 01-May-2011
• Replaced By: ASTM F316-03(2019) - Standard Test Methods for Pore Size Characteristics of Membrane Filters by Bubble Point and Mean Flow Pore Test
• Effective Date: 01-Nov-2019
• Referred By: ASTM F2450-18 - Standard Guide for Assessing Microstructure of Polymeric Scaffolds for Use in Tissue-Engineered Medical Products
• Effective Date: 01-May-2011
• Referred By: ASTM F2150-19 - Standard Guide for Characterization and Testing of Biomaterial Scaffolds Used in Regenerative Medicine and Tissue-Engineered Medical Products
• Effective Date: 01-May-2011
• Referred By: ASTM F561-19 - Standard Practice for Retrieval and Analysis of Medical Devices, and Associated Tissues and Fluids
• Effective Date: 01-May-2011
• Referred By: ASTM D7898-14(2020) - Standard Practice for Lubrication and Hydraulic Filter Debris Analysis (FDA) for Condition Monitoring of Machinery
• Effective Date: 01-May-2011
• Referred By: ASTM D8194-18e1 - Standard Practice for Evaluation of Suitability of 37 mm Filter Monitors and 47 mm Filters Used to Determine Particulate Contaminant in Aviation Turbine Fuels
• Effective Date: 01-May-2011
• Referred By: ASTM F2902-16e1 - Standard Guide for Assessment of Absorbable Polymeric Implants
• Effective Date: 01-May-2011
• Referred By: ASTM F3510-21 - Standard Guide for Characterizing Fiber-Based Constructs for Tissue-Engineered Medical Products
• Effective Date: 01-May-2011

Standards Content (Sample)

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: F316 − 03 (Reapproved 2011)
Standard Test Methods for
Pore Size Characteristics of Membrane Filters by Bubble
Point and Mean Flow Pore Test
ThisstandardisissuedunderthefixeddesignationF316;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginal
adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.Asuperscript
epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope D1193 Specification for Reagent Water
D2777 Practice for Determination of Precision and Bias of
1.1 These test methods cover the determination of two of
Applicable Test Methods of Committee D19 on Water
the pore size properties of membrane filters with maximum
E128 Test Method for Maximum Pore Diameter and Perme-
pore sizes from 0.1 to 15.0 µm.
ability of Rigid Porous Filters for Laboratory Use
1.2 Test MethodApresents a test method for measuring the
maximum limiting pore diameter of nonfibrous membranes.
3. Terminology
The limiting diameter is the diameter of a circle having the
3.1 Definitions—For definitions of other terms used in these
same area as the smallest section of a given pore (Fig. 1).
test methods, refer to Terminology D1129.
1.3 Test Method B measures the relative abundance of a
3.2 Definitions of Terms Specific to This Standard:
specified pore size in a membrane, defined in terms of the
3.2.1 pore size—capillary equivalent pore diameter.
limiting diameter.
3.2.2 limiting pore diameter—diameter of a circle having
1.4 The analyst should be aware that adequate collaborative
the same area as the smallest section of a given pore.
data for bias statements as required by Practice D2777 is not
provided. See the precision and bias section for details.
TEST METHOD A—MAXIMUM PORE SIZE
1.5 The values stated in SI units are to be regarded as
standard. No other units of measurement are included in this
4. Summary of Test Method
standard.
4.1 The bubble point test for maximum pore size is per-
1.6 This standard does not purport to address all of the
formed by prewetting the filter, increasing the pressure of gas
safety concerns, if any, associated with its use. It is the
upstream of the filter at a predetermined rate and watching for
responsibility of the user of this standard to establish appro-
gas bubbles downstream to indicate the passage of gas through
priate safety, health, and environmental practices and deter-
the maximum diameter filter pores.
mine the applicability of regulatory limitations prior to use.
1.7 This international standard was developed in accor-
4.2 The pressure required to blow the first continuous
dance with internationally recognized principles on standard-
bubbles detectable by their rise through a layer of liquid
ization established in the Decision on Principles for the
covering the filter is called the "bubble point", and is used to
Development of International Standards, Guides and Recom-
calculate maximum pore size.
mendations issued by the World Trade Organization Technical
Barriers to Trade (TBT) Committee.
5. Significance and Use
2. Referenced Documents
5.1 This test method may be used to:
2 5.1.1 Determine the maximum pore size of a filter,
2.1 ASTM Standards:
5.1.2 Compare the maximum pore sizes of several filters,
D1129 Terminology Relating to Water
and
5.1.3 Determine the effect of various processes such as
These test methods are under the jurisdiction of ASTM Committee D19 on
filtration, coating, or autoclaving on the maximum pore size of
Water and are the direct responsibility of Subcommittee D19.08 on Membranes and
Ion Exchange Materials.
a membrane.
Current edition approved May 1, 2011. Published June 2011. Originally
5.2 Membrane filters have discrete pores from one side to
approved in 1970. Last previous edition approved in 2003 as F316 – 03. DOI:
10.1520/F0316-03R11.
the other of the membrane, similar to capillary, tubes. The
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
bubble point test is based on the principle that a wetting liquid
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
is held in these capillary pores by capillary attraction and
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. surface tension, and the minimum pressure required to force
Copyright ©ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA19428-2959. United States
F316 − 03 (2011)
7. Reagents
7.1 Purity of Reagents—Reagent grade chemicals shall be
used in all tests. Unless otherwise indicated, it is intended that
all reagents shall conform to the specifications of the Commit-
tee on Analytical Reagents of the American Chemical Society
where such specifications are available. Other grades may be
used provided it is first ascertained that the reagent is of
sufficient high purity to permit its use without lessening the
accuracy of the determination.
FIG. 1 Examples of Limiting Diameters
7.2 Water, conforming to Specification D1193, Type IV or
higher purity.
liquid from these pores is a function of pore diameter. The
pressureatwhichasteadystreamofbubblesappearsinthistest 7.3 Denatured Alcohol.
is the bubble point pressure.The bubble point test is significant
7.4 Petroleum Distillate, with surface tension of 30
not only for indicating maximum pore size, but may also
dynes/cm at 25°C.
indicate a damaged membrane, ineffective seals, or a system
leak.
7.5 Mineral Oil, such as USP liquid petrolatum heavy, with
surface tension of 34.7 dynes/cm at 25°C.
5.3 The results of this test method should not be used as the
sole factor to describe the limiting size for retention of
7.6 1,1.2-trichloro-l,2,2-trifluoroethane (Freon TF®),avail-
particulate contaminants from fluids. The effective pore size
able from commercial chemical supply houses.
calculated from this test method is based on the premise of
7.7 Clean Gas Pressure Source, with regulation (filtered air
capillary pores having circular cross sections, and does not
or nitrogen).
refertoactualparticlesizeretention.SeeTestMethodE128for
NOTE 2—Table 1 lists the nominal surface tension of these liquids at
additional information.
25°C. Table 2 lists the simplified maximum pore size formulas based on
these values, where the liquid completely wets the membrane.
6. Apparatus
6.1 Filter Holder, as shown in Fig. 2, consisting of a baseA,
8. Procedure
a locking ring B, O-ring seal C, support disk D, and gas inlet
8.1 Wet the test membrane completely by floating it on a
E. The support disk shall be 2-ply construction, consisting of a
pool of the liquid. Use a vacuum chamber to assist in wetting
100 by 100 mesh or finer screen and a perforated metal plate
the filter, if needed.
for rigidity. The diameter of the test filter may be either 25 or
47 mm, as appropriate to the holder being used for the test.
8.2 Place the wet membrane in the filter holder.
6.2 Manifold,asshowninFig.3,amicrometricflowcontrol
8.3 Close the filter holder and apply slight gas pressure to
valve capable of providing a linear rise in pressure and a gas
3 eliminate possible liquid back flow.
ballast of at least 16 000-cm capacity.
NOTE 1—For less accurate determinations, the simplified apparatus
8.4 Cover the perforated metal plate with 2 to 3 mm of test
shown in Fig. 4 may be used.
liquid.
6.3 Pressure Gages (and mercury manometer if required),
8.5 Increase the gas pressure slowly. Record the lowest
covering the range of pressures needed for the pore sizes under
pressure at which a steady stream of bubbles rises from the
investigation (see Table 1).
central area of the liquid reservoir.
6.4 Metal Punch, used to cut a suitable size filter from the
NOTE 3—Faulty sealing may cause erroneous bubbling from the sealing
test sheet to fit the test filter holder.
edge of the liquid reservoir. Be sure to record the bubble point pressure
with bubbles from the central area of the reservoir (see Fig. 5).
9. Calculation
9.1 If the test liquid is known to wet the membrane
completely, calculate the maximum pore size from the follow-
ing equation:
d 5 Cγ/p (1)
Reagent Chemicals, American Chemical Society Specifications, American
Chemical Society, Washington, DC. For Suggestions on the testing of reagents not
listed by the American Chemical Society, see Annual Standards for Laboratory
Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia
and National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,
FIG. 2 Filter Holder MD.
F316 − 03 (2011)
Key Quantity Component
1 1 Filter
2 1 Pressure regulator
3 1 Pressure gage
4 1 Valve shutoff, manual
5 1 Valve, flow control, manual
6 4 Valve, solenoid, nc
7 1 Air ballast
8 1 Quick disconnect fitting
9 2 Open filter holder, 47 mm
10 1 Valve, 3-way, manual
11 1 Test gage, 0-0.3 kPa (0-30 psig)
12 1 Test gage, 0-0.8 kPa (0-100 psig)
13 1 Exhaust silencer
14 2 Pilot light, red, elec.
15 1 Switch, spdt, elec.
FIG. 3 Manifold for Bubble Point Testing
calculated effective pore size will be larger than the actual effective pore
size rating.
10. Reporting Results
10.1 Record the minimum pressure for gas passage as
indicated by continuous bubbles. Record the maximum pore
size calculated, along with identification of the membrane
tested and the liquid used.
TEST METHOD B—DETERMINATION OF PORE
SIZE DISTRIBUTION
11. Summary of Test Method
FIG. 4 Test Setup (Simplified)
11.1 A fluid-wet filter will pass air when the applied air
pressure exceeds the capillary attraction of the fluid in the
where: pores. Smaller pores will exhibit similar behavior at higher
pressures. The relationship between pore size and pressure has
d = limiting diameter, µm,
γ = surface tension, mN/m, (dynes/cm), been established, as indicated in Table 2
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