ASTM_D_6478_-_10_2014.pdf

Designation:D647810(Reapproved 2014)Standard Test Method forDetermining Specific Packability of Fabrics Used inInflatable Restraints1This standard is issued under the fixed designation D6478;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 test method covers procedures for determining theability to fold and pack fabrics used for inflatable restraintsusing an index of specific packability.1.2 Procedures in this test method describe operator tech-niques that must be followed closely to obtain repeatable andaccurate results.Since these techniques are difficult to conveyin writing,supplemental training for operators is required.Atraining video is available from ASTM(see AdjunctsADJD6478 and ADJD6478A).1.3 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.4 Procedures and apparatus other than those stated in thispractice may be used as agreed upon between the purchaserand the supplier with specific deviations from this practiceacknowledged in the report.1.5 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)3D6799 Terminology Relating to Inflatable RestraintsE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method2.2 ASTM Adjuncts:ADJD6478 17 Detailed Drawings4ADJD6478A Videotape-Supplemental Training43.Terminology3.1 For all terminology relating to D13.20,Inflatablerestraints,refer to Terminology D6799.3.1.1 The following terms are relevant to this standard:inflatable restraint,packability,specific packability.3.2 For all other terms related to textiles,see TerminologyD123.4.Summary of Test Method4.1 Afabric specimen is folded uniformly in a“Z”pattern inthe warp and fill directions.4.2 The folded specimen is placed into a transparent boxthat confines the specimen securely during compression.4.3 The folded specimen is compressed using a tensile testeroutfitted with special hardware,and the resulting volume isrecorded at specified loads.The total of all the individualvolumes recorded at each specified cell is the specific pack-ability of the fabric.5.Significance and Use5.1 This test method is useful for determining the specificpackability of uncoated and coated airbag fabrics.Fabricpackability is an important factor in the design of airbagmodules due to their inherent spacial constraints.5.2 A folded specimen exhibits better specific packability ifit occupies a lower total volume at the specified loads com-pared to another specimen.5.3 The time required to test one sample(four specimensfrom the same lot of fabric)is approximately 1.5 h using thistest method.Due to the length of time required by this testmethod to perform a single test,this test method is most1This test method is under the jurisdiction ofASTM Committee D13 on Textilesand is the direct responsibility of Subcommittee D13.20 on Inflatable Restraints.Current edition approved July 1,2014.Published August 2014.Originallyapproved in 1999.Last previous edition approved in 2010 as D647810.DOI:10.1520/D6478-10R14.2For 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.4Available from ASTM International Headquarters.For 17 Detailed CADDrawings,Order Adjunct No.ADJD6478.For Videotape-Supplemental Training,Order ADJD6478A.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 suitable for use in design and development analysis or forinclusion in a list of required tests conducted for annualcertification of an airbag fabric.6.Apparatus6.1 Tensile Tester,outfitted with a rigid base to support thespecimen box,and a compression foot attached to the load cellwith a coupling having adjustment and locking capability tomaintain fixed parallel alignment to the base.Tensile testershould be calibrated annually by an independent agency whoseresults are traceable to the National Institute of Science andTechnology(NIST)or other national standards laboratory.NOTE1The frame of the tensile tester can be used as the rigid base ifi