ASTM_F_2476_-_13.pdf

Designation:F247613Standard Test Method forthe Determination of Carbon Dioxide Gas Transmission Rate(CO2TR)Through Barrier Materials Using An InfraredDetector1This standard is issued under the fixed designation F2476;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()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This method covers a procedure for determination of thesteady-state rate of transmission of carbon dioxide gas throughplastics in the form of film,sheeting,laminates,coextrusions,or plastic-coated papers or fabrics.It provides for the determi-nation of(1)carbon dioxide gas transmission rate(CO2TR),(2)the permeance of the film to carbon dioxide gas(PCO2),and(3)carbon dioxide permeability coefficient(P”CO2)in thecase of homogeneous materials.1.2 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regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2D1898 Practice for Sampling of Plastics(Withdrawn 1998)3E177 Practice for Use of the Terms Precision and Bias inASTM Test MethodsE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method3.Terminology3.1 Definitions:3.1.1 carbon dioxide permeability coeffcient(P”CO2)theproduct of the permeance and the thickness of film.Thepermeability is meaningful only for homogeneous materials,inwhich case it is a property characteristic of the bulk material.This quantity should not be used unless the relationshipbetween thickness and permeance has been verified on testsusing several different thicknesses of the material.The SI unitof carbon dioxide permeability is the mol/msPa.The testconditions(see 3.1.3)must be stated.3.1.2 carbon dioxide permeance(PCO2)the ratio of theCO2TR to the difference between the partial pressure of CO2on the two sides of the film.The SI unit of permeance is themol/(m2sPa).The test conditions(see 3.1.3)must be stated.3.1.3 carbon dioxide transmission rate(CO2TR)Thequantity of carbon dioxide gas passing through a unit area ofthe parallel surfaces of a plastic film per unit time under theconditions of the test.The SI unit of transmission rate is themol/(m2s).The test conditions,including temperature andcarbon dioxide partial pressure on both sides of the film,mustbe stated.3.1.3.1 DiscussionA commonly used metric unit ofCO2TR is the cc(STP)/(m2day)at one atmosphere drivingforce pressure differential where:1 cc(STP)is 44.62 mol.1atm is 0.1013 MPa.and one day is 86.4 x 103s.CO2TR in SIunits is obtained by multiplying the value in metric units by5.164 x 10-10or the value in inch-pound units cm3(STP)(100in.2 day)by 8.004 x 10-9.4.Summary of Test Method4.1 The carbon dioxide gas transmission rate is determinedafter the sample has equilibrated in a dry-test environment.Inthis context,a“dry”environment is considered to be one inwhich the relative humidity is less than 1%.4.2 The specimen is mounted as a sealed semi-barrierbetween two chambers at ambient atmospheric pressure.Onechamber is slowly purged by a stream of nitrogen and the otherchamber with carbon dioxide.As carbon dioxide gas permeatesthrough the film into the nitrogen carrier gas,it is transportedto an infrared detector where an electrical output is producedwhose magnitude is proportional to the amount of CO2flowinginto the detector per unit of time.5.Significance and Use5.1 Carbon dioxide gas transmission rate(CO2TR)is animportant determinant of the packaging protection afforded by1This test method is under jurisdiction of ASTM Committee F02 on FlexibleBarrier Packaging and is the direct responsibility of Subcommittee F02.10 onPermeation.Current edition approved Dec.15,2013.Published February 2014.Originallyapproved in 2005.Last previous edition approved in 2005 as F2476-05.DOI:10.1520/F2476-13.2For 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.3The last approved version of this historical standard is referenced onwww.astm.org.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 barrier materials.It is not,however,the sole determinant,andadditional tests,based on experience,must be used to correlatepackaging performance with CO2TR.It is suitable as a refereemethod of testing,provided that purchaser and seller haveagreed on sampling procedures,standardization procedures,test conditions and acceptance criteria.6.Apparatus6.1 Carbon Dioxide Gas Transmission Apparatus,as dia-grammed in Fig.1 or Fig.2,with th