ASTM_E_1294_-_89_1999.pdf

Designation:E 1294 89(Reapproved 1999)Standard Test Method forPore Size Characteristics of Membrane Filters UsingAutomated Liquid Porosimeter1This standard is issued under the fixed designation E 1294;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon(e)indicates an editorial change since the last revision or reapproval.1.Scope1.1 This test method describes a procedure for measuringthe pore size characteristics of membrane filters in the range ofapproximately 0.05 to 300 m.1.2 This test method uses the automated bubble pointmethod described in ASTM Test Method F 316.1.3 The liquid displacement technique used in this testmethod depends upon the capillary rise created by surfacetension and uses the Washburn equation for calculating thepore diameter.1.4 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:F 316 Test Method for Pore Size Characteristics of Mem-brane Filters for Use with Aerospace Fluids23.Summary of Test Method3.1 A filter wet with liquid exhibits properties similar tothose of array of liquid filled capillaries(see Note).The sampleunder test is thoroughly wetted with liquid of low surfacetension and low vapor pressure and placed in a sample holderassembly.An increasing air pressure is applied upstream of thesample and as successively smaller pores empty,the air flowacross the sample is recorded as a function of applied pressure.The point of first flow is identified as the bubble point(maximum pore size).This continues until the smallest detect-able pore is reached.This information is then compared withthe flow rate against applied pressure response for the drysample.The pore size distribution is then obtained from wetand dry curves.NOTE1This test method will not change the priorities of themembrane if the test liquids are chosen to be compatible with the materialfrom which it is made.4.Significance and Use4.1 This test method may be used to determine the maxi-mum pore size,minimum pore size,and mean flow pore size.4.2 The pore size distributions by flow,number,and volumecan be deduced from pressure versus flow data.5.Apparatus5.1 Source of Compressed Air up to 150 psi.5.2 Automated Liquid Porosimeter.35.3 Sample Holders.5.4 Metal Punch,used to cut a suitable size membrane filterfrom the test sheet to fit the test filter holder.6.Reagents and Materials6.1 Purity of ReagentsReagent grade chemicals shall beused in all tests.Unless otherwise indicated,it is intended thatall reagents shall conform to the specifications of the Commit-tee on Analytical Reagents of the American Chemical Societywhere such specifications are available.4Other grades may beused,provided it is first ascertained that the reagent is ofsufficiently high purity to permit its use without lessening theaccuracy of the determination.6.2 Porofil.56.3 Isopropyl Alcohol.6.4 Water.6.5 Mineral Oil.7.Procedure7.1 Follow the manufacturers operating instructions toprepare the sample to introduce to the instrument for analysis.7.2 Establish standard sampling procedures to obtain repeat-able results.8.Operating Instructions8.1 Operating instructions shall be supplied by the manu-facturer with every instrument.The instructions shall contain:1This test method is under the jurisdiction of ASTM Committee E-48 onBiotechnology and is the direct responsibility of Subcommittee E48.03 on UnitProcesses and Their Control.Current edition approved March 31,1989.Published May 1989.2Annual Book of ASTM Standards,Vol 11.01.3Coulter Porometer available from Coulter Electronics,Inc.,601 W.20th Street,Hialeah,Florida 33010 U.S.A.,has been found suitable for this purpose.4“Reagent Chemicals,American Chemical Society Specifications,AmericanChemical Society,Washington DC.For suggestions on the testing of reagents nolisted by theAmerican Chemical Society,see“Analar Standards for Laboratory U.K.Chemicals,”BDH Ltd.,Poole,Dorset,and the“United States Pharmacopeia.”5Porofil wetting liquid,available from Coulter Electronics,Inc.,has been foundsuitable for this purpose.1Copyright ASTM,100 Barr Harbor Drive,West Conshohocken,PA 19428-2959,United States.8.1.1 Brief instructions of the operating principles of theinstrument,8.1.2 Description of various systems,8.1.3 Pore size range limitations,8.1.4 Suggested maintenance procedures,and8.1.5 Recommended spare parts.9.Verification9.1 Verification of the performance of the instrument func-tion may be determined by using well characterized track-etched polycarbonate membrane filters6within the range of theinstrument.9.2 Interlaboratory comparisons within a particular industryshould be made using t