ASTM_D_4846_-_96_2021.pdf

Designation:D484696(Reapproved 2021)Standard Test Method forResistance to Unsnapping of Snap Fasteners1This standard is issued under the fixed designation D4846;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 the determination of the forcerequired to disengage snap fasteners by a pull perpendicular toand parallel with the plane of the snap fastener.1.2 This test method requires attachment of snaps to speci-mens using specifications provided by the producers of thesnaps.1.3 This test method is used to establish correlation to wearconditions and for comparing different brands and types ofsnap fasteners.1.4 The values stated in SI units are to be regarded asstandard.The values given in parentheses after SI units areprovided for information only and are not considered standard.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,health,and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.6 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade(TBT)Committee.2.Referenced Documents2.1 ASTM Standards:2D76/D76M Specification for Tensile Testing Machines forTextilesD123 Terminology Relating to TextilesD1776/D1776M Practice for Conditioning and Testing Tex-tiles3.Definitions3.1 lateral holding strength,nthe force required to disen-gage a snap fastener resulting from a pull in the plane parallelto the material to which the snap fastener is attached.3.2 snap action,nthe force required to disengage a snapfastener resulting from a pull exerted perpendicular to the planeof material to which the snap fastener is attached.3.3 snap fastener,na device for attaching one material toanother consisting of matching male and female parts,each ofwhich is attached to a separate material so that the parts can bejoined by a low compressive force and separated by a lowperpendicular tensile force.3.4 For definitions of other textile terms used in this testmethod,refer to Terminology D123.4.Summary of Test Method4.1 Snap fasteners mounted on strips of material near theend are tested on standard tensile testing machines equippedfor testing the strength of textile fabrics and having sensitivityfor accurate low force levels.4.2 Tests are made on snap fasteners before laundering withthe option of testing again after a pre-determined number oflaunderings or other types of refurbishing.5.Significance and Use5.1 This test method may be used for acceptance testing ofcommercial shipments of snap fasteners,but caution is advisedsince information on between laboratory precision is incom-plete.Comparative tests as directed in 5.1.1 are advisable.5.1.1 In case of a dispute arising from differences inreported test results when using Test Method D4846 foracceptance testing of commercial shipments,the purchaser andseller should conduct comparative tests to determine if there isstatistical bias between their laboratories.Competent statisticalassistance is recommended for the investigation of bias.As aminimum,the two parties should take a group of test speci-mens that are as homogeneous as possible and that are from alot of material of the type in question.The test specimens thenshould be assigned randomly in equal numbers to eachlaboratory for testing.The average results from the twolaboratories should be compared using Students t-test forunpaired data and an acceptable probability level chosen by the1This test method is under the jurisdiction ofASTM Committee D13 on Textilesand is the direct responsibility of Subcommittee D13.54 on Subassemblies.Current edition approved July 1,2021.Published July 2021.Originally approvedin 1988.Last previous edition approved in 2016 as D4846 96(2016).DOI:10.1520/D4846-96R21.2For 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.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade(TBT)Committee.1two