ASTM_F_316_-_03_2011.pdf

Designation:F31603(Reapproved 2011)Standard Test Methods forPore Size Characteristics of Membrane Filters by BubblePoint and Mean Flow Pore Test1This standard is issued under the fixed designation F316;the number immediately following the designation indicates the year of originaladoption or,in the case of revision,the year of last revision.Anumber in parentheses indicates the year of last reapproval.Asuperscriptepsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 These test methods cover the determination of two ofthe pore size properties of membrane filters with maximumpore sizes from 0.1 to 15.0 m.1.2 Test Method A presents a test method for measuring themaximum limiting pore diameter of nonfibrous membranes.The limiting diameter is the diameter of a circle having thesame area as the smallest section of a given pore(Fig.1).1.3 Test Method B measures the relative abundance of aspecified pore size in a membrane,defined in terms of thelimiting diameter.1.4 The analyst should be aware that adequate collaborativedata for bias statements as required by Practice D2777 is notprovided.See the precision and bias section for details.1.5 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.6 This standard may involve hazardous materials,operations,and equipment.This standard does not purport toaddress all of the safety concerns,if any,associated with itsuse.It is the responsibility of the user of this standard toestablish appropriate safety and health practices and deter-mine the applicability of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2D1129 Terminology Relating to WaterD1193 Specification for Reagent WaterD2777 Practice for Determination of Precision and Bias ofApplicable Test Methods of Committee D19 on WaterE128 Test Method for Maximum Pore Diameter and Perme-ability of Rigid Porous Filters for Laboratory Use3.Terminology3.1 DefinitionsFor definitions of other terms used in thesetest methods,refer to Terminology D1129.3.2 Definitions of Terms Specific to This Standard:3.2.1 pore sizecapillary equivalent pore diameter.3.2.2 limiting pore diameterdiameter of a circle havingthe same area as the smallest section of a given pore.TEST METHOD AMAXIMUM PORE SIZE4.Summary of Test Method4.1 The bubble point test for maximum pore size is per-formed by prewetting the filter,increasing the pressure of gasupstream of the filter at a predetermined rate and watching forgas bubbles downstream to indicate the passage of gas throughthe maximum diameter filter pores.4.2 The pressure required to blow the first continuousbubbles detectable by their rise through a layer of liquidcovering the filter is called the bubble point,and is used tocalculate maximum pore size.5.Significance and Use5.1 This test method may be used to:5.1.1 Determine the maximum pore size of a filter,5.1.2 Compare the maximum pore sizes of several filters,and5.1.3 Determine the effect of various processes such asfiltration,coating,or autoclaving on the maximum pore size ofa membrane.5.2 Membrane filters have discrete pores from one side tothe other of the membrane,similar to capillary,tubes.Thebubble point test is based on the principle that a wetting liquidis held in these capillary pores by capillary attraction andsurface tension,and the minimum pressure required to forceliquid from these pores is a function of pore diameter.Thepressure at which a steady stream of bubbles appears in this testis the bubble point pressure.The bubble point test is significant1These test methods are under the jurisdiction of ASTM Committee D19 onWater and are the direct responsibility of Subcommittee D19.08 on Membranes andIon Exchange Materials.Current edition approved May 1,2011.Published June 2011.Originallyapproved in 1970 as F316 70.Last previous edition approved in 2003 asF316 03.DOI:10.1520/F0316-03R11.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 not only for indicating maximum pore size,but may alsoindicate a damaged membrane,ineffective seals,or a systemleak.5.3 The results of this test method should not be used as thesole factor to describe the limiting size for retention ofparticulate contaminants from fluids.The effective pore sizecalculated from this test method is based on the premise ofcapillary pores having circular cross sections,and does notrefer to actual particle size retention.See Test Method E128 foradditional information.6.Apparatus6.1 Filter Holder,as shown in Fig.2,consisting of a baseA,a locking ring B,O-ring seal C,support disk D,and gas inletE.The support disk shall be 2-ply construction,consisting of a100 by 100 mesh or fi