ASTM_D_1388_-_14e1.pdf

Designation:D1388141Standard Test Method forStiffness of Fabrics1This standard is issued under the fixed designation D1388;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 U.S.Department of Defense.1NOTEIn 10.3.4,“Rotate.the right-hand bar in a clockwise direction”was corrected to“counterclockwise”in October2015.1.Scope1.1 This test method covers the measurement of stiffnessproperties of fabrics.Bending length is measured and flexuralrigidity is calculated.Two procedures are provided.1.1.1 Option ACantilever Test,employing the principle ofcantilever bending of the fabric under its own mass.1.1.2 Option BHeart Loop Test,employing the principleof a loop formed in a fabric strip and hung vertically.1.2 This test method applies to most fabrics includingwoven fabrics,air bag fabrics,blankets,napped fabrics,knittedfabrics,layered fabrics,pile fabrics.The fabrics may beuntreated,heavily sized,coated,resin-treated,or otherwisetreated.1.3 The values stated in SI units are to be regarded as thestandard.The U.S.customary units may be approximate.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Produces Normally Distributed Data(With-drawn 2008)3D2906 Practice for Statements on Precision and Bias forTextiles(Withdrawn 2008)3D3776 Test Methods for Mass Per Unit Area(Weight)ofFabricD4850 Terminology Relating to Fabrics and Fabric TestMethods3.Terminology3.1 For all terminology relating to D13.59,Fabric TestMethods,General,refer to Terminology D4850.3.1.1 The following terms are relevant to this standard:bending length,cross-machine direction,CD,fabric,flexuralrigidity,machine direction,MD,stiffness.3.2 For all other terminology related to textiles,refer toTerminology D123.4.Summary of Test Method Options4.1 Option A,Cantilever TestA specimen is slid at aspecified rate in a direction parallel to its long dimension,untilits leading edge projects from the edge of a horizontal surface.The length of the overhang is measured when the tip of thespecimen is depressed under its own mass to the point wherethe line joining the top to the edge of the platform makes a0.724 rad(41.5)angle with the horizontal.From this mea-sured length,the bending length and flexural rigidity arecalculated.4.2 Option B,Heart Loop TestA strip of fabric is formedinto a heart-shaped loop.The length of the loop is measuredwhen it is hanging vertically under its own mass.From thismeasured length,the bending length and flexural rigidity arecalculated.5.Significance and Use5.1 Both test options in this test method are consideredsatisfactory for acceptance testing of commercial shipmentssince current estimates of between-laboratory precision areacceptable and the method is used extensively in the trade foracceptance testing.5.1.1 In case of a dispute arising from differences inreported test results when using this test method for acceptance1This test method is under the jurisdiction ofASTM Committee D13 on Textilesand is the direct responsibility of Subcommittee D13.60 on Fabric Test Methods,Specific.Current edition approved July 1,2014.Published August 2014.Originallyapproved in 1956.Discontinued 1995 and reinstated as D1388 96.Last previousedition approved in 2012 as D138808(2012).DOI:10.1520/D1388-14E01.2For 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 testing of commercial shipments,the purchaser and the sup-plier should conduct comparative tests to determine if there isa statistical bias between their laboratories.Competent statis-tical assistance is recommended for the investigation of bias.As a minimum,the two parties should take a group of testspecimens that are as homogeneous as possible and that arefrom a lot of material of the type in question.Test specimensshould then be randomly assigned in equal numbers to eachlaboratory for testing.The average results from the twolaboratories should be compared using the appropriate statis-tical analysis and an accep