ASTM D4846-96(2021)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: D4846 − 96 (Reapproved 2021)
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. Definitions
3.1 lateral holding strength, n—the force required to disen-
1.1 This test method covers the determination of the force
gage a snap fastener resulting from a pull in the plane parallel
required to disengage snap fasteners by a pull perpendicular to
to the material to which the snap fastener is attached.
and parallel with the plane of the snap fastener.
3.2 snap action, n—the force required to disengage a snap
1.2 This test method requires attachment of snaps to speci-
fastenerresultingfromapullexertedperpendiculartotheplane
mens using specifications provided by the producers of the
of material to which the snap fastener is attached.
snaps.
3.3 snap fastener, n—a device for attaching one material to
1.3 This test method is used to establish correlation to wear
another consisting of matching male and female parts, each of
conditions and for comparing different brands and types of
which is attached to a separate material so that the parts can be
snap fasteners.
joined by a low compressive force and separated by a low
1.4 The values stated in SI units are to be regarded as
perpendicular tensile force.
standard. The values given in parentheses after SI units are
3.4 For definitions of other textile terms used in this test
provided for information only and are not considered standard.
method, refer to Terminology D123.
1.5 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
4. Summary of Test Method
responsibility of the user of this standard to establish appro-
4.1 Snap fasteners mounted on strips of material near the
priate safety, health, and environmental practices and deter-
end are tested on standard tensile testing machines equipped
mine the applicability of regulatory limitations prior to use.
for testing the strength of textile fabrics and having sensitivity
1.6 This international standard was developed in accor-
for accurate low force levels.
dance with internationally recognized principles on standard-
4.2 Tests are made on snap fasteners before laundering with
ization established in the Decision on Principles for the
the option of testing again after a pre-determined number of
Development of International Standards, Guides and Recom-
launderings or other types of refurbishing.
mendations issued by the World Trade Organization Technical
Barriers to Trade (TBT) Committee.
5. Significance and Use
2. Referenced Documents
5.1 This test method may be used for acceptance testing of
2 commercial shipments of snap fasteners, but caution is advised
2.1 ASTM Standards:
since information on between laboratory precision is incom-
D76/D76M Specification for Tensile Testing Machines for
plete. Comparative tests as directed in 5.1.1 are advisable.
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/D1776M Practice for Conditioning and Testing Tex-
acceptance testing of commercial shipments, the purchaser and
tiles
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
This test method is under the jurisdiction ofASTM Committee D13 on Textiles
minimum, the two parties should take a group of test speci-
and is the direct responsibility of Subcommittee D13.54 on Subassemblies.
mens that are as homogeneous as possible and that are from a
Current edition approved July 1, 2021. Published July 2021. Originally approved
lot of material of the type in question. The test specimens then
in 1988. Last previous edition approved in 2016 as D4846 – 96 (2016). DOI:
10.1520/D4846-96R21.
should be assigned randomly in equal numbers to each
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
laboratory for testing. The average results from the two
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
laboratories should be compared using Student’s t-test for
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. unpaired data and an acceptable probability level chosen by the
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D4846 − 96 (2021)
level, and limiting quality level.
two parties before testing is begun. If a bias is found, either its
cause must be found and corrected or the purchaser and seller
7.2 Laboratory Sample—As a laboratory sample for accep-
must agree to interpret future test results in the light of the
tance testing, proceed as follows:
known bias.
7.2.1 Unattached Snap Fasteners—Take one box or card of
unattached snap fasteners at random from each shipping carton
6. Apparatus
in the lot sample. If the male and female parts are packed
6.1 Tensile Testing Machine—A constant rate of extension
separately, take one box of each from each shipping carton in
(CRE) type or constant rate of traverse (CRT) type testing
the lot sample.
machine conforming to Specification D76/D76M 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 mm
garments with more than five. If less than five, take all snap
by 100 mm by 4 mm (2 in. by 4 in. by ⁄8 in.) with dowel pins
fasteners from each garment.
inserted (see 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/D1776M.
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
...