ASTM D7142-05
(Test Method)Standard Test Method for Holding Strength of Prong-Ring Attached Snap Fasteners
Standard Test Method for Holding Strength of Prong-Ring Attached Snap Fasteners
SCOPE
1.1 This test method covers the determination of the 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 specification.
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 appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
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Designation:D7142–05
Standard Test Method for
Holding Strength of Prong-Ring Attached Snap Fasteners
This standard is issued under the fixed designation D7142; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 3.1.1 force, n—a physical influence exerted by one body on
another which produces acceleration of bodies that are free to
1.1 Thistestmethodcoversthedeterminationoftheholding
move and deformation of bodies that are not free to move.
strength of a prong-ring to the socket or stud of a snap fastener
3.1.2 holding strength, n—in snap fasteners, the force re-
using a tensile testing machine (Option 1) or a manual test
quired to separate the prong-ring from its attached mating part
stand and force-measuring gage (Option 2).
(socket or stud).
1.2 This test method is applicable to prong-ring type snap
3.1.2.1 Discussion—In this test method, a diametric force is
fasteners in garments or to be attached to fabrics intended for
applied which simulates the diametric biting or pinching of a
use in apparel (see Annex A1).
child; however, in practice, the disengaging force used to
1.3 The values stated in either SI units or inch-pound units
unsnap a snap fastener is usually applied at the edge of the
are to be regarded separately as standard. Within the text, the
fastener.
inch-pound units are shown in parentheses. The values stated
3.1.3 prong-ring type fastener, n—generic name for snap
in each system are not exact equivalents; therefore, each
fasteners which use a multi-pronged ring to penetrate through
system shall be used independently of the other. Combining
fabric to mechanically set a matching socket on one side of a
values from the two systems may result in non-conformance
closure and to set a matching stud on the facing closure
with the specification.
allowing the outer and inner closure facings to be snapped
1.4 This standard does not purport to address all of the
together. (See Fig. 1.)
safety concerns, if any, associated with its use. It is the
3.1.4 socket, n—in snap fasteners, the female functional
responsibility of the user of this standard to establish appro-
part of the fastener which engages with the stud part of the
priate safety and health practices and determine the applica-
fastener to form the closure of two parts of the item on which
bility of regulatory limitations prior to use.
the fastener is used. (See Fig. 1.)
2. Referenced Documents
3.1.4.1 Discussion—Prong-ring attached socket or stud
snap fasteners are designed to be mechanically attached to
2.1 ASTM Standards:
garments or other items through the deformation interaction of
D76 Specification for Tensile Testing Machines for Textiles
the prong-ring with the socket or stud. Other forms of snap
D123 Terminology Relating to Textiles
fasteners exist which may be attached to the foundation of the
D1776 Practice for Conditioning and Testing Textiles
garment or other item by means of sewn threads or adhesive
2.2 Federal Document:
bonding.
16 CFR Parts 1500.48-1500.53 and 1501.4 Engineering
3.1.5 strength, n—the property of a material that resists
Test Manual for Children’s Toys
deformation induced by external forces.
3. Terminology
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
3.1 Definitions:
fastener.
3.1.6 stud, n—in snap fasteners, the male functional part of
This test method is under the jurisdiction ofASTM Committee D13 onTextiles
asnapfastenerwhichengageswith,orsnapsinto,themouthof
and is the direct responsibility of Subcommittee D13.54 on Subassemblies.
thesockettoformaclosureoftwopartsoftheitem,orgarment
Current edition approved July 1, 2005. Published August 2005. DOI: 10.1520/
on which the fastener is used. (See Fig. 1.)
D7142-05.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
3.1.6.1 Discussion—See discussion for socket.
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
3.1.7 For definitions of other textile terms used in this
Standards volume information, refer to the standard’s Document Summary page on
standard, refer to Terminology D123.
the ASTM website.
Available from Federal Register, Vol 44, No. 117, June 1979, Consumer
Product Commission, 16 CFR Parts 1500 and 1501.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D7142–05
FIG. 1 Prong-ring Attached Fastener Parts
4. Summary of Test Method supplier must agree to interpret future test results with consid-
eration to the known bias.
4.1 Option 1—A specimen, consisting of a fastener socket
5.2 Comparison of results from test equipment operating on
or stud attached to fabric by a prong-ring, is mounted in a
special test fixture on a tensile testing machine. A force is different principles is not recommended. In cases of conflict
between the test results achieved with manual test equipment
applied diametrically until the prong-ring separates from the
socket or stud, or the fabric is torn. The force at separation is (Option 2) and motorized CRE (constant rate of extension)
tensile testing machine (Option 1), the results from the motor-
reported as the holding strength. If the fabric tears, the force at
fabric failure is recorded and the data is reported and it is ized equipment shall take precedence.
consideredasadifferentcategoryandisreportedseparatefrom
5.3 This test method may be used to determine the compat-
the holding strength of the fasteners.
ibility of prong-ring type snap fasteners and fabrics for use in
4.2 Option 2—A specimen, consisting of a fastener socket
apparel. In which case, the fasteners are attached to the fabric
or stud attached to fabric by a prong-ring, is mounted in a
in the manner in which they will be used and the combined
special test fixture on a manual pull test stand which is fitted
units tested. See Annex A1.
with a portable force gage. A force is applied until the
prong-ring separates from the socket or stud, or the fabric is
6. Apparatus
torn.Theforceatseparationisreportedastheholdingstrength.
6.1 For Option 1:
If the fabric tears, the force at fabric failure is recorded and the
6.1.1 Tensile Testing Machine, CRE type, meeting Specifi-
data is reported and it is considered as a different category and
cation D76. (See Figs. 2 and 3.)
is reported separate from the holding strength of the fasteners.
6.1.2 Upper Snap Fixture Attachment 4, Fig. 4, designed to
5. Significance and Use
diametrically attach to the socket or stud of the snap fastener
5.1 Both test methods are considered satisfactory for accep- which is attached to the fabric specimen or garment being
tested.
tance testing of commercial shipments of garments with
prong-ring type snap fasteners.
6.1.3 Lower Snap FixtureAttachment 4, Fig. 4, designed to
5.1.1 In case of dispute arising from differences in reported
secure the fabric and thereby the socket or stud attached to it in
test results when using this test method for acceptance of
a horizontal plane.
commercial shipment, the purchaser and the supplier should
6.2 For Option 2:
conduct comparative tests to determine if there is a statistical
6.2.1 Force Measuring Gage 5, modified with an attachment
bias between their laboratories. Competent statistical assis-
tobefastenedontotheupperarmofateststandwiththeupper
tance is recommended for the investigation of bias. As a
test fixture suspended from it. (See Fig. 3.)
minimum, the two parties should take a group of test speci-
6.2.2 Upper Snap Fixture Attachment 4, Fig. 4, designed to
mens that are as homogeneous as possible and that are from a
diametrically attach to the socket or stud of the snap fastener
lot of material of the type in question. The test specimens
which is attached to the fabric specimen or garment being
should then be randomly assigned in equal numbers to each
tested.
laboratory for testing. The average results from the two
6.2.3 Lower Snap FixtureAttachment 4, Fig. 4, designed to
laboratories should be compared using appropriate statistical
secure the fabric and thereby the socket or stud attached to it in
analysis and an acceptable probability level chosen by the
a horizontal plane.
parties before testing is begun. If a bias is found, either the
cause must be determined and corrected, or the purchaser and 6.2.4 Test Stand, see Fig. 5.
D7142–05
FIG. 2 CRE-Type Tensile Testing Machine setup With Test FIG. 3 Closeup of CRE-Type Tensile Testing Machine Fixture
Fixtures For Option 1. Setup.
7. Sampling
clamping in the fixtures. Specimens need not be cut from the
7.1 Lot Sample:
garment provided that the garment does not interfere with the
7.1.1 For acceptance testing, randomly select the number of
test.
shipping cartons or other containers of garments
...
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