ASTM D4846-96(2011)
(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.
In case of a dispute arising from differences in reported test results when using Test Method D4846 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's 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)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: D4846 − 96(Reapproved 2011)
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 3.3 snap fastener, n—a device for attaching one material to
another consisting of matching male and female parts, each of
1.1 This test method covers the determination of the force
which is attached to a separate material so that the parts can be
required to disengage snap fasteners by a pull perpendicular to
joined by a low compressive force and separated by a low
and parallel with the plane of the snap fastener.
perpendicular tensile force.
1.2 This test method requires attachment of snaps to speci-
3.4 For definitions of other textile terms used in this test
mens using specifications provided by the producers of the
method, refer to Terminology D123.
snaps.
1.3 This test method is used to establish correlation to wear
4. Summary of Test Method
conditions and for comparing different brands and types of
4.1 Snap fasteners mounted on strips of material near the
snap fasteners.
end are tested on standard tensile testing machines equipped
1.4 The values stated in SI units are to be regarded as the
for testing the strength of textile fabrics and having sensitivity
standard. The values stated in the parentheses are for informa-
for accurate low force levels.
tion only.
4.2 Tests are made on snap fasteners before laundering with
1.5 This standard does not purport to address all of the
the option of testing again after a pre-determined number of
safety concerns, if any, associated with its use. It is the
launderings or other types of refurbishing.
responsibility of the user of this standard to establish appro-
priate safety and health practices and determine the applica-
5. Significance and Use
bility of regulatory limitations prior to use.
5.1 This test method may be used for acceptance testing of
commercial shipments of snap fasteners, but caution is advised
2. Referenced Documents
since information on between laboratory precision is incom-
2.1 ASTM Standards:
plete. Comparative tests as directed in 5.1.1 are advisable.
D76 Specification for Tensile Testing Machines for Textiles
5.1.1 In case of a dispute arising from differences in
D123 Terminology Relating to Textiles
reported test results when using Test Method D4846 for
D1776 Practice for Conditioning and Testing Textiles
acceptance testing of commercial shipments, the purchaser and
seller should conduct comparative tests to determine if there is
3. Definitions
statistical bias between their laboratories. Competent statistical
assistance is recommended for the investigation of bias. As a
3.1 lateral holding strength, n—the force required to disen-
minimum, the two parties should take a group of test speci-
gage a snap fastener resulting from a pull in the plane parallel
mens that are as homogeneous as possible and that are from a
to the material to which the snap fastener is attached.
lot of material of the type in question. The test specimens then
3.2 snap action, n—the force required to disengage a snap
should be assigned randomly in equal numbers to each
fastenerresultingfromapullexertedperpendiculartotheplane
laboratory for testing. The average results from the two
of material to which the snap fastener is attached.
laboratories should be compared using Student’s 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
This test method is under the jurisdiction ofASTM Committee D13 on Textiles
cause must be found and corrected or the purchaser and seller
and is the direct responsibility of Subcommittee D13.54 on Subassemblies.
must agree to interpret future test results in the light of the
Current edition approved Jan. 1, 2011. Published March 2011. Originally
known bias.
approved in 1988 as D4846 – 88. Last previous edition approved in 2004 as
D4846 – 96(2004). DOI: 10.1520/D4846-96R11.
For referenced ASTM standards, visist the ASTM wbsite, www.astm.org, or 6. Apparatus
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
6.1 Tensile Testing Machine—A constant rate of extension
Standardsvolume information, refer to the standard’s Document Summary page on
the ASTM website. (CRE) type or constant rate of traverse (CRT) type testing
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D4846 − 96 (2011)
machine conforming to Specification D76 with a rate of 7.2.2 Attached Snap Fasteners—Take one garment from
traverse of 305 mm (12 in.)/min, or a rate agreed upon between each shipping carton in the lot sample.
purchaser and seller, and a scale which will produce accurate
7.3 Test Specimens:
results at very low force levels. There may be no overall
7.3.1 Unattached Snap Fasteners—From each box or card
correlationbetweentheresultsobtainedwiththeCREandCRT
in the laboratory sample, take five snap fasteners at random. If
tensile testing machines. In the case of controversy, however,
the male and female parts are packed separately, for each pair
the CRE method shall prevail.
of boxes from a shipping carton in the lot sample, take five
6.2 Jaws—The back jaws of the clamps on the tensile male parts at random and match them with five female parts
testing machine should be at least the same width as the front taken at random.
jaws. The front jaws must be 25.4 mm (1 in.) wide. 7.3.2 Attached Snap Fasteners—From each garment in the
laboratory sample, take five snap fasteners at random on
6.3 Aluminum Plate—A plate is required measuring 50 by
garments with more than five. If less than five, take all snap
100by4mm(2by4by ⁄8 in.) with dowel pins inserted (see
fasteners from each garment.
Fig. 1).
6.4 Attaching Machine—A hand operated, foot operated, or
8. Conditioning
automatic machine for attaching snap fastener parts conform-
8.1 Condition the specimens by bringing them from the dry
ing to specifications of seller.
side to approximate moisture equilibrium for testing in the
standard atmosphere for testing textiles as directed in Practice
7. Sampling
D1776.
7.1 LotSample—Asalotsampleforacceptancetesting,take
at random the number of shipping cartons of snap fasteners or
9. Procedure
shipping cartons of garments directed in an applicable material
9.1 Preparing Specimens:
specification or other agreement between the purchaser and the
9.1.1 Attaching Loose Snap Fasteners—When snap fasten-
seller. Consider shipping cartons of snap fasteners or shipping
ers are to be attached to a material typical to intended
cartons of garments to be the primary 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.
fabri
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