ASTM_D_737_-_04_2012.pdf

Designation:D73704(Reapproved 2012)Standard Test Method forAir Permeability of Textile Fabrics1This standard is issued under the fixed designation D737;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.This standard has been approved for use by agencies of the Department of Defense.1.Scope1.1 This test method covers the measurement of the airpermeability of textile fabrics.1.2 This test method applies to most fabrics includingwoven fabrics,nonwoven fabrics,air bag fabrics,blankets,napped fabrics,knitted fabrics,layered fabrics,and pile fabrics.The fabrics may be untreated,heavily sized,coated,resin-treated,or otherwise treated.1.3 The values stated in SI units are to be regarded as thestandard.The values stated in inch-pound units may beapproximate.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:2D123 Terminology Relating to TextilesD1776 Practice for Conditioning and Testing TextilesD2904 Practice for Interlaboratory Testing of a Textile TestMethod that Produces Normally Distributed Data(With-drawn 2008)3D2906 Practice for Statements on Precision and Bias forTextiles(Withdrawn 2008)3D4850 Terminology Relating to Fabrics and Fabric TestMethodsF778 Methods for Gas Flow Resistance Testing of FiltrationMedia3.Terminology3.1 For definition of textile terms used in this test method:air permeability,and fabric,refer to Terminology D4850.3.2 For definitions of cross-machine direction;machinedirection and other textile terms used in this test method,referto Terminology D123.4.Summary of Test Method4.1 The rate of air flow passing perpendicularly through aknown area of fabric is adjusted to obtain a prescribed airpressure differential between the two fabric surfaces.From thisrate of air flow,the air permeability of the fabric is determined.5.Significance and Use5.1 This test method is considered satisfactory for accep-tance testing of commercial shipments since current estimatesof between-laboratory precision are acceptable,and this testmethod is used extensively in the trade for acceptance testing.5.1.1 If there are differences of practical significance be-tween reported test results for two laboratories(or more),comparative tests should be performed to determine if there isa statistical bias between them,using competent statisticalassistance.As a minimum,ensure the test samples to be usedare as homogeneous as possible,are drawn from the materialfrom which the disparate test results were obtained,and arerandomly assigned in equal number to each laboratory fortesting.The test results from the two laboratories should becompared using a statistical test for unpaired data,at aprobability level chosen prior to the testing series.If bias isfound,either its cause must be found and corrected,or futuretest results for that material must be adjusted in considerationof the known bias.5.2 Air permeability is an important factor in the perfor-mance of such textile materials as gas filters,fabrics for airbags,clothing,mosquito netting,parachutes,sails,tentage,andvacuum cleaners.In filtration,for example,efficiency isdirectly related to air permeability.Air permeability also can beused to provide an indication of the breathability of weather-resistant and rainproof fabrics,or of coated fabrics in general,and to detect changes during the manufacturing process.1This test method is under the jurisdiction ofASTM Committee D13 on Textilesand is the direct responsibility of Subcommittee D13.59 on Fabric Test Methods,General.Current edition approved July 1,2012.Published August 2012.Originallyapproved in 1943.Last previous edition approved in 2008 as D737 04(2008).DOI:10.1520/D0737-04R12.2For 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 5.3 Performance specifications,both industrial and military,have been prepared on the basis of air permeability and areused in the purchase of fabrics where permeability is ofinterest.5.4 Construction factors and finishing techniques can havean appreciable effect upon air permeability by causing a changein the length of airflow paths through a fabric.Hot calendaringcan be used to flatten fabric components,thus reducing airper