ASTM D7142-05(R2021) pdf free download

ASTM D7142-05(R2021) pdf free download.Standard Test Method for Holding Strength of Prong-Ring Attached Snap Fasteners
1. Scope
1.1 This test method covers the determination ofthe holding strength of a prong-ring to the socket or stud of a snap fastener using a tensile testing machine (Option 1) or a manual test stand and force-measuring gage (Option 2). 1.2 This test method is applicable to prong-ring type snap fasteners in garments or to be attached to fabrics intended for use in apparel (see Annex A1). 1.3 The values stated in either SI units or inch-pound units are to be regarded separately as standard. Within the text, the inch-pound units are shown in parentheses. The values stated in each system are not exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in non-conformance with the standard. 1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appro- priate safety, health, and environmental practices and deter- mine the applicability ofregulatory limitations prior to use. 1.5 This international standard was developed in accor- dance with internationally recognized principles on standard- ization established in the Decision on Principles for the Development of International Standards, Guides and Recom- mendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
3. Terminology
3.1 Definitions: 3.1.1 force, n—a physical influence exerted by one body on another which produces acceleration of bodies that are free to move and deformation of bodies that are not free to move. 3.1.2 holding strength, n—in snap fasteners, the force re- quired to separate the prong-ring from its attached mating part (socket or stud). 3.1.2.1 Discussion—In this test method, a diametric force is applied which simulates the diametric biting or pinching of a child; however, in practice, the disengaging force used to unsnap a snap fastener is usually applied at the edge of the fastener. 3.1.3 prong-ring type fastener, n—generic name for snap fasteners which use a multi-pronged ring to penetrate through fabric to mechanically set a matching socket on one side of a closure and to set a matching stud on the facing closure allowing the outer and inner closure facings to be snapped together. (See Fig. 1.) 3.1.4 socket, n—in snap fasteners, the female functional part of the fastener which engages with the stud part of the fastener to form the closure of two parts of the item on which the fastener is used. (See Fig. 1.) 3.1.4.1 Discussion—Prong-ring attached socket or stud snap fasteners are designed to be mechanically attached to garments or other items through the deformation interaction of the prong-ring with the socket or stud. Other forms of snap fasteners exist which may be attached to the foundation of the garment or other item by means of sewn threads or adhesive bonding. 3.1.5 strength, n—the property of a material that resists deformation induced by external forces. 3.1.5.1 Discussion—In this standard, the deformation is the separation of the prong-ring from the socket or stud of a snap fastener.
4. Summary of Test Method
4.1 Option 1—A specimen, consisting of a fastener socket or stud attached to fabric by a prong-ring, is mounted in a special test fixture on a tensile testing machine. A force is applied diametrically until the prong-ring separates from the socket or stud, or the fabric is torn. The force at separation is reported as the holding strength. If the fabric tears, the force at fabric failure is recorded and the data is reported and it is considered as a different category and is reported separate from the holding strength of the fasteners. 4.2 Option 2—A specimen, consisting of a fastener socket or stud attached to fabric by a prong-ring, is mounted in a special test fixture on a manual pull test stand which is fitted with a portable force gage. A force is applied until the prong-ring separates from the socket or stud, or the fabric is torn. The force at separation is reported as the holding strength. If the fabric tears, the force at fabric failure is recorded and the data is reported and it is considered as a different category and is reported separate from the holding strength of the fasteners.