ASTM_D_7142_-_05_2011.pdf

Designation:D714205(Reapproved 2011)Standard Test Method forHolding Strength of Prong-Ring Attached Snap Fasteners1This standard is issued under the fixed designation D7142;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 holdingstrength of a prong-ring to the socket or stud of a snap fastenerusing a tensile testing machine(Option 1)or a manual teststand and force-measuring gage(Option 2).1.2 This test method is applicable to prong-ring type snapfasteners in garments or to be attached to fabrics intended foruse in apparel(see Annex A1).1.3 The values stated in either SI units or inch-pound unitsare to be regarded separately as standard.Within the text,theinch-pound units are shown in parentheses.The values statedin each system are not exact equivalents;therefore,eachsystem shall be used independently of the other.Combiningvalues from the two systems may result in non-conformancewith the specification.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:2D76 Specification for Tensile Testing Machines for TextilesD123 Terminology Relating to TextilesD1776 Practice for Conditioning and Testing Textiles2.2 Federal Document:16 CFR Parts 1500.48-1500.53 and 1501.4 Engineering TestManual for Childrens Toys33.Terminology3.1 Definitions:3.1.1 force,na physical influence exerted by one body onanother which produces acceleration of bodies that are free tomove and deformation of bodies that are not free to move.3.1.2 holding strength,nin snap fasteners,the force re-quired to separate the prong-ring from its attached mating part(socket or stud).3.1.2.1 DiscussionIn this test method,a diametric force isapplied which simulates the diametric biting or pinching of achild;however,in practice,the disengaging force used tounsnap a snap fastener is usually applied at the edge of thefastener.3.1.3 prong-ring type fastener,ngeneric name for snapfasteners which use a multi-pronged ring to penetrate throughfabric to mechanically set a matching socket on one side of aclosure and to set a matching stud on the facing closureallowing the outer and inner closure facings to be snappedtogether.(See Fig.1.)3.1.4 socket,nin snap fasteners,the female functional partof the fastener which engages with the stud part of the fastenerto form the closure of two parts of the item on which thefastener is used.(See Fig.1.)3.1.4.1 DiscussionProng-ring attached socket or stud snapfasteners are designed to be mechanically attached to garmentsor other items through the deformation interaction of theprong-ring with the socket or stud.Other forms of snapfasteners exist which may be attached to the foundation of thegarment or other item by means of sewn threads or adhesivebonding.3.1.5 strength,nthe property of a material that resistsdeformation induced by external forces.3.1.5.1 DiscussionIn this standard,the deformation is theseparation of the prong-ring from the socket or stud of a snapfastener.3.1.6 stud,nin snap fasteners,the male functional part ofa snap fastener which engages with,or snaps into,the mouth ofthe socket to form a closure of two parts of the item,or garmenton which the fastener is used.(See Fig.1.)3.1.6.1 DiscussionSee discussion for socket.3.1.7 For definitions of other textile terms used in thisstandard,refer to Terminology D123.1This test method is under the jurisdiction ofASTM Committee D13 on Textilesand is the direct responsibility of Subcommittee D13.54 on Subassemblies.Current edition approved Jan.1,2011.Published March 2011.Originallyapproved in 2005.Last previous edition approved in 2005 as D7142-05.DOI:10.1520/D7142-05R11.2For 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.3Available from Federal Register,Vol 44,No.117,June 1979,ConsumerProduct Commission,16 CFR Parts 1500 and 1501.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 4.Summary of Test Method4.1 Option 1A specimen,consisting of a fastener socketor stud attached to fabric by a prong-ring,is mounted in aspecial test fixture on a tensile testing machine.A force isapplied diametrically until the prong-ring separates from thesocket or stud,or the fabric is torn.The force at separation isreported as the holding strength.If the fabric tears,the force atfabric failure is r