ASTM D4846-96(2004)
(Test Method)Standard Test Method for Resistance to Unsnapping of Snap Fasteners
Standard Test Method for Resistance to Unsnapping of Snap Fasteners
SIGNIFICANCE AND USE
This test method may be used for acceptance testing of commercial shipments of snap fasteners, but caution is advised since information on between laboratory precision is incomplete. Comparative tests as directed in 5.1.1 are advisable.
5.1.1 In case of a dispute arising from differences in reported test results when using Test Method D 4846 for acceptance testing of commercial shipments, the purchaser and seller should conduct comparative tests to determine if there is statistical bias between their laboratories. Competent statistical assistance is recommended for the investigation of bias. As a minimum, the two parties should take a group of test specimens that are as homogeneous as possible and that are from a lot of material of the type in question. The test specimens then should be assigned randomly in equal numbers to each laboratory for testing. The average results from the two laboratories should be compared using Student’t-test for unpaired data and an acceptable probability level chosen by the two parties before testing is begun. If a bias is found, either its cause must be found and corrected or the purchaser and seller must agree to interpret future test results in the light of the known bias.
SCOPE
1.1 This test method covers the determination of the force required to disengage snap fasteners by a pull perpendicular to and parallel with the plane of the snap fastener.
1.2 This test method requires attachment of snaps to specimens using specifications provided by the producers of the snaps.
1.3 This test method is used to establish correlation to wear conditions and for comparing different brands and types of snap fasteners.
1.4 The values stated in SI units are to be regarded as the standard. The values stated in the parentheses are for information only.
1.5 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.
General Information
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Standards Content (Sample)
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Designation:D4846–96 (Reapproved 2004)
Standard Test Method for
Resistance to Unsnapping of Snap Fasteners
This standard is issued under the fixed designation D4846; 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 joined by a low compressive force and separated by a low
perpendicular tensile force.
1.1 This test method covers the determination of the force
3.4 For definitions of other textile terms used in this test
required to disengage snap fasteners by a pull perpendicular to
method, refer to Terminology D123.
and parallel with the plane of the snap fastener.
1.2 This test method requires attachment of snaps to speci-
4. Summary of Test Method
mens using specifications provided by the producers of the
4.1 Snap fasteners mounted on strips of material near the
snaps.
end are tested on standard tensile testing machines equipped
1.3 This test method is used to establish correlation to wear
for testing the strength of textile fabrics and having sensitivity
conditions and for comparing different brands and types of
for accurate low force levels.
snap fasteners.
4.2 Tests are made on snap fasteners before laundering with
1.4 The values stated in SI units are to be regarded as the
the option of testing again after a pre-determined number of
standard. The values stated in the parentheses are for informa-
launderings or other types of refurbishing.
tion only.
1.5 This standard does not purport to address all of the
5. Significance and Use
safety concerns, if any, associated with its use. It is the
5.1 This test method may be used for acceptance testing of
responsibility of the user of this standard to establish appro-
commercial shipments of snap fasteners, but caution is advised
priate safety and health practices and determine the applica-
since information on between laboratory precision is incom-
bility of regulatory limitations prior to use.
plete. Comparative tests as directed in 5.1.1 are advisable.
5.1.1 In case of a dispute arising from differences in
2. Referenced Documents
reported test results when using Test Method D4846 for
2.1 ASTM Standards:
acceptance testing of commercial shipments, the purchaser and
D76 Specification for Tensile Testing Machines for Textiles
seller should conduct comparative tests to determine if there is
D123 Terminology Relating to Textiles
statistical bias between their laboratories. Competent statistical
D1776 Practice for Conditioning and Testing Textiles
assistance is recommended for the investigation of bias. As a
3. Definitions minimum, the two parties should take a group of test speci-
mens that are as homogeneous as possible and that are from a
3.1 lateral holding strength, n—the force required to disen-
lot of material of the type in question. The test specimens then
gage a snap fastener resulting from a pull in the plane parallel
should be assigned randomly in equal numbers to each
to the material to which the snap fastener is attached.
laboratory for testing. The average results from the two
3.2 snap action, n—the force required to disengage a snap
laboratories should be compared using Student’s t-test for
fastenerresultingfromapullexertedperpendiculartotheplane
unpaired data and an acceptable probability level chosen by the
of material to which the snap fastener is attached.
two parties before testing is begun. If a bias is found, either its
3.3 snap fastener, n—a device for attaching one material to
cause must be found and corrected or the purchaser and seller
another consisting of matching male and female parts, each of
must agree to interpret future test results in the light of the
which is attached to a separate material so that the parts can be
known bias.
6. Apparatus
This test method is under the jurisdiction ofASTM Committee D13 onTextiles
6.1 Tensile Testing Machine—A constant rate of extension
and is the direct responsibility of Subcommittee D13.54 on Subassemblies.
(CRE) type or constant rate of traverse (CRT) type testing
Current edition approved Sept. 10, 1996. Published November 1996. Originally
published as D4846 – 88. DOI: 10.1520/D4846-96R04.
machine conforming to Specification D76 with a rate of
For referenced ASTM standards, visist the ASTM wbsite, www.astm.org, or
traverse of 305 mm (12 in.)/min, or a rate agreed upon between
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
purchaser and seller, and a scale which will produce accurate
Standardsvolume information, refer to the standard’s Document Summary page on
the ASTM website. results at very low force levels. There may be no overall
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D4846–96 (2004)
correlationbetweentheresultsobtainedwiththeCREandCRT 7.3.1 Unattached Snap Fasteners—From each box or card
tensile testing machines. In the case of controversy, however, in the laboratory sample, take five snap fasteners at random. If
the CRE method shall prevail. the male and female parts are packed separately, for each pair
6.2 Jaws—The back jaws of the clamps on the tensile of boxes from a shipping carton in the lot sample, take five
testing machine should be at least the same width as the front male parts at random and match them with five female parts
jaws. The front jaws must be 25.4 mm (1 in.) wide. taken at random.
6.3 Aluminum Plate—A plate is required measuring 50 by 7.3.2 Attached Snap Fasteners—From each garment in the
100by4mm(2by4by ⁄8 in.) with dowel pins inserted (see laboratory sample, take five snap fasteners at random on
Fig. 1). garments with more than five. If less than five, take all snap
6.4 Attaching Machine—Ahand operated, foot operated, or fasteners from each garment.
automatic machine for attaching snap fastener parts conform-
8. Conditioning
ing to specifications of seller.
8.1 Condition the specimens by bringing them from the dry
7. Sampling
side to approximate moisture equilibrium for testing in the
standard atmosphere for testing textiles as directed in Practice
7.1 Lot Sample—As a lot sample for acceptance testing,
D1776.
take at random the number of shipping cartons of snap
fasteners or shipping cartons of garments directed in an
9. Procedure
applicable material specification or other agreement between
9.1 Preparing Specimens:
the purchaser and the seller. Consider shipping cartons of snap
fasteners or shipping cartons of garments to be the primary 9.1.1 Attaching Loose Snap Fasteners—When snap fasten-
ers are to be attached to a material typical to intended
sampling units.
production, the pinch setting and other conditions specified by
NOTE 1—An adequate specification or other agreement between the
the seller must be used. Cut fabric specimens to dimensions of
purchaser and the seller requires taking into account the variability
38 by 89 mm (1.5 by 3.5 in.) and attach male part to one fabric
between shipping cartons, units within a shipping carton, and between
specimen and female part to the other fabric specimen, both
specimensfromaunitwithinashippingcarton,toprovideasamplingplan
with a meaningful producer’s risk, consumer’s risk, acceptable quality
approximately 19 mm ( ⁄4 in.) from the ends or edge of the
level, and limiting quality level.
fabric specimens (see Fig. 2).
9.1.2 Cutting Specimens From Garmen
...
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