ASTM D1424-21

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Designation: D1424 − 09 (Reapproved 2019) D1424 − 21
Standard Test Method for
Tearing Strength of Fabrics by Falling-Pendulum
(Elmendorf-Type) Apparatus
This standard is issued under the fixed designation D1424; 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.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope
1.1 This test method covers the determination of the force required to propagate a single-rip tear starting from a cut in a fabric
and using a falling-pendulum (Elmendorf-Type) apparatus.
1.2 This test method applies to most fabrics including woven, layered blankets, napped pile, blanket, and air bag fabrics, provided
the fabric does not tear in the direction crosswise to the direction of the force application during the test. The fabrics may be
untreated, heavily sized, coated, resin-treated, or otherwise treated. Instructions are provided for testing specimens with, or without,
wetting.
1.3 This test method is suitable only for the warp direction tests of warp-knit fabrics. It is not suited for the course direction of
warp knit fabrics or either direction of most other knitted fabrics.
1.4 The values stated in either SI units or U.S. customary units are to be regarded as standard, but must be used independently
of each other. The U.S. customary units may be approximate.
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, health, and environmental practices and determine the applicability of
regulatory limitations prior to use.
1.6 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.
2. Referenced Documents
2.1 ASTM Standards:
D123 Terminology Relating to Textiles
D629 Test Methods for Quantitative Analysis of Textiles
D1776 Practice for Conditioning and Testing Textiles
D2261 Test Method for Tearing Strength of Fabrics by the Tongue (Single Rip) Procedure (Constant-Rate-of-Extension Tensile
Testing Machine)
This test method is under the jurisdiction of ASTM Committee D13 on Textiles and is the direct responsibility of Subcommittee D13.60 on Fabric Test Methods, Specific.
Current edition approved July 1, 2019July 1, 2021. Published July 2019August 2021. Originally approved in 1956. Last previous edition approved in 20132019 as
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D1424 – 09 (2013)(2019). . DOI: 10.1520/D1424-09R19.10.1520/D1424-21.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D1424 − 21
D2904 Practice for Interlaboratory Testing of a Textile Test Method that Produces Normally Distributed Data (Withdrawn 2008)
D2906 Practice for Statements on Precision and Bias for Textiles (Withdrawn 2008)
D4848 Terminology Related to Force, Deformation and Related Properties of Textiles
D4850 Terminology Relating to Fabrics and Fabric Test Methods
D5587 Test Method for Tearing Strength of Fabrics by Trapezoid Procedure
3. Terminology
3.1 For all terminology relating to D13.59, Fabric Test Methods, General, refer to Terminology D4850.
3.2 For all terminology relating to Force, Deformation and Related Properties in Textiles, refer to Terminology D4848.
3.2.1 The following terms are relevant to this standard: cross-machine direction, CD, length of tear, machine direction, MD,
tearing energy, tearing force, tear resistance, tearing strength, fabric.
3.3 For all other terminology related to textiles, refer to Terminology D123.
4. Summary of Test Method
4.1 A slit is centrally precut in a test specimen held between two clamps and the specimen is torn through a fixed distance. The
resistance to tearing is in part factored into the scale reading of the instrument and is computed from this reading and the pendulum
capacity.
5. Significance and Use
5.1 This test method for the determination of tearing strength by the falling pendulum type apparatus is used in the trade for the
acceptance testing of commercial shipments of fabrics, but caution is advised since technicians may fail to get good agreement
between results on certain fabrics. Comparative tests as directed in 5.1.1 may be needed.
5.1.1 In case of a dispute arising from differences in reported test results when using this test method for acceptance testing of
commercial shipments, the purchaser and the supplier should conduct comparative tests to determine if there is a statistical bias
between their laboratories. 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 fabric of the type in question.
The test specimens should then be randomly assigned in equal numbers to each laboratory for testing. The average results from
the two laboratories should be compared using appropriate statistical analysis and an acceptable probability level chosen by the
two parties before the testing began. If a bias is found, either its cause must be found and corrected or the purchaser and the supplier
must agree to interpret future test results with consideration to the known bias.
5.2 Microprocessor systems for automatic collection of data can provide economical and reliable results when properly calibrated.
See Test Methods D2261 and D5587.
6. Apparatus
6.1 Falling-Pendulum (Elmendorf-Type) Tester —The tester includes: a stationary clamp, a clamp carried on a pendulum that is
free to swing on a bearing, means for leveling as applicable, means for holding the pendulum in a raised position, means for
instantly releasing the pendulum, and means for measuring the force to tear the test specimen.
6.1.1 A knife can be mounted on a stationary post for initial slitting of the specimens centered between the clamps and adjusted
in height to give a tearing distance of 43.0 6 0.15 mm (1.69 6 0.005 in.); that is, the distance between the end of the slit made
by the knife and the upper edge of the specimen is 43.0 6 0.15 mm (1.69 6 0.005 in.) when the lower edge of the 63.0-mm 63.0
mm (2.5 6 0.005 in.) wide specimen rests against the bottom of the clamp.
6.1.2 With the pendulum in its initial position ready for a test, the two clamps are separated by a distance of 2.53.0 6 0.250.5 mm
(0.1(0.12 6 0.010.02 in.) and are aligned such that the clamped specimen lies in a plane parallel to the axis of the pendulum, the
The last approved version of this historical standard is referenced on www.astm.org.
Apparatus is commercially available.
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plane making an angle of 0.480 rad (27.5 6 0.5°) with the perpendicular line joining the axis and the horizontal line formed by
the top edges of the clamping jaws. The distance between the axis and the top edges of the clamping jaws is 103104 6 0.11 mm
(4.055(4.09 6 0.0040.02 in.). The clamping surface in each jaw is at least 25 mm (1.0 in.) wide and 15.9 6 0.1 mm (0.625 6
0.004 in.) deep.
6.1.3 The tester may have a pointer mounted on the same axis as the pendulum to register the tearing force, or it may be substituted
by means of calculating and displaying the required results without the use of a pointer, such as digital display and computer driven
systems. Preferably the clamps may be air actuated, but manual clamping is permitted.
6.1.4 The test instrument should be equipped to provide interchangeable full scale force ranges. Typical full scale ranges are
shown in Table A3.1.
6.2 Calibration Weight(s) for graduation of 50 % of the full scale force range, or other means as described by the manufacturer
of the test apparatus.
6.3 Cutting Die having essentially the shape and dimensions shown in Fig. 1(a) or (b). Either die provides the basic rectangular
test specimen 100 6 2 mm (4 6 0.05 in.) long by 63 6 0.15 mm (2.5 6 0.005 in.) wide, along with additional fabric at the top
edge of the specimen to help ensure the bottom portion of specimen will be torn during the test. The critical dimension of the test
specimen is the distance 43.0 6 0.15 mm (1.69 6 0.005 in.) which is to be torn during the test.
NOTE 1—The improved die model shown in Fig. 1(a) has two new features not found in the original model, Fig. 1(b), namely a cutout for the bottom
of the specimen to aid in centering it in the clamps, and (optional) provision for cutting the 20.0 mm (0.75 in.) slit prior to inserting the specimen in the
tester. These dies can be made to order by most die manufacturers.
6.4 Air Pressure Regulator, capable of controlling gauge air pressure between 410 kPa and 620 kPa (60 psi and 90 psi), when
applicable, for air clamps.
6.5 Setting Gauge for Cutting Blade that will provide a cut slit that leaves a 43 6 0.15 mm (1.69 6 0.005 in.) specimen tearing
distance for a 63 6 0.15 mm (2.5 6 0.005 in.) wide specimen, or equivalent.
6.6 Jaw Spacing Gauge 2.5 6 0.25 mm (0.1 6 0.01 in.) width, or equivalent.
6.7 Oil, light weight, non-gumming clock type.
6.8 Silicone Grease, when applicable, for air clamp lubrication.
6.9 Vacuum Cleaner, when applicable, for cleaning dust and fiber from sensor, or equivalent.
7. Sampling and Test Specimens
7.1 Lot Sample—As a lot sample for acceptance testing, randomly select the number of rolls or pieces of fabric directed in an
FIG. 1 Die Diagram for Cutting Notched Specimens
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applicable material specification or other agreement between the purchaser and the supplier. Consider the rolls or pieces of fabric
to be the primary sampling units. In the absence of such an agreement, take the number of fabric rolls or pieces specified in Table
1.
NOTE 2—An adequate specification or other agreement between the purchaser and supplier requires taking into account the variability between rolls or
pieces of fabric and between specimens from a swatch from a roll or piece of fabric to provide a sampling plan with a meaningful producer’s risk,
consumer’s risk, acceptable quality level, and limiting quality level.
7.2 Laboratory Sample—For acceptance testing, take a swatch extending the width of the fabric and approximately 1 m (1 yd)
along the machine direction from each roll or piece in the lot sample. For rolls of fabric, take a sample that will exclude fabric
from the outer wrap of the roll or the inner wrap around the core of the roll of fabric.
7.3 Test Specimens—From each laboratory sampling unit, take five specimens from the machine direction and five specimens from
the cross-machine direction, for each test condition described in 9.1 and 9.2, as applicable to a material specification or contract
order.
7.3.1 Direction of Test—Consider the long direction of the specimen as the direction of test.
7.3.2 Cutting Test Specimens—Take the specimens to be used for the measurement of machine direction with the longer dimension
parallel to the machine direction. Take the specimens to be used for the measurement of the cross-machine with the longer
dimension parallel to the cross-machine direction. Use the cutting die described in 6.3 and shown in Fig. 1(a) or (b), as applicable.
When specimens are to be tested wet, cut from areas adjacent to the dry test specimens. Label to maintain specimen identity.
7.3.2.1 In cutting the woven fabric specimens, take care to align the yarns running in the short direction parallel with the die such
that when the slit is cut, the subsequent tear will take place between these yarns and not across them. This precaution is most
important when testing bowed fabrics.
7.3.2.2 Cut specimens representing a broad distribution across the width and length, and preferably along the diagonal of the
laboratory sample, and no nearer the edge than one-tenth its width. Ensure specimens are free of folds, creases, or wrinkles. Avoid
getting oil, water, grease, etc. on the specimens when handling.
NOTE 3—The reading obtained is directly proportional to the length of the material torn, therefore, it is essential that the specimen be prepared to the exact
size specified.
8. Preparation of Apparatus and Calibration
8.1 Select test instrument force range, such that the tear occurs between 20 and 80 % or 20 and 60 % of the full-scale range as
applicable. Ensure the clamps are spaced as directed in A1.4.
NOTE 4—For standard test apparatus, the useable portion of the full scale force range is 20 to 80 %. For the high capacity test instrument, the useable
portion of the full scale force range is 20 to 60 %.
8.2 When equipped with a registering sensor, examine the scale and the complementary sensor, as applicable. Using care and
without touching the sensor, vacuum away any loose fibers and dust.
8.3 Examine the knife edge for sharpness, wear, and central alignment as directed in A1.5 – A1.7.
8.4 For air clamps, set the air gauge pressure to the clamps to about 550 kPa (80 psi).
TABLE 1 Number of Rolls or Pieces of Fabric in the Lot Sample
Number of Rolls or Pieces Number of Rolls or Pieces in Lot
in Lot, Inclusive Sample
1 to 3 all
4 to 24 4
25 to 50 5
over 50 10 % to a max of 10 rolls or pieces
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8.4.1 Maximum gauge pressure should be no more than 620 kPa (90 psi) and minimum gauge pressure no less than 410 kPa (60
psi).
8.5 When using microprocessor automatic data gathering systems, set the appropriate parameters as defined in the manufacturer’s
instructions.
8.6 Verify the calibration of the selected pendulum full scale force range using the procedure described in Annex A2, unless
otherwise specified.
9. Conditioning
9.1 Condition 1, Standard Testing Conditioning:
9.1.1 Precondition the specimens by bringing them to approximate moisture equilibrium in the standard atmosphere for
preconditioning textiles as directed in Practice D1776, unless otherwise directed in a material specification or contract order.
9.1.2 After preconditioning, bring the test specimens to moisture equilibrium for testing in the standard atmosphere for testing
textiles as directed in Practice D1776 or, if applicable, in the specified atmosphere in which the testing is to be performed, unless
otherwise directed in a material specification or contract order.
9.2 Condition 2, Wet Specimen Testing Conditioning:
9.2.1 When desizing treatments are specified prior to wet testing, use desizing treatments that will not affect the normal physical
property of the fabric as directed in Test Method D629.
9.2.2 Submerge the specimens in a container of distilled or deionized water at ambient temperature until thoroughly soaked.
9.2.2.1 The time of immersion must be sufficient to wet out the specimens, as indicated by no significant change in tearing force
followed by longer periods of immersion. For most fabrics this time period will be about 1 h. For fabrics not readily wet out with
water, such as those treated with water-repellent, or water resistant materials, add a 0.1 % solution of a nonionic wetting agent to
the water bath.
10. Procedure
10.1 Test the conditioned specimens in the standard atmosphere for testing textiles, which is 21 6 1°C (70 6 2°F) and 65 6 2 %
relative humidity, unless otherwise directed in a material specification or contract order.
10.2 Position the pendulum to the starting position and the force recording mechanism to its zero-force position.
10.3 For Tester-Slit Specimens:
10.3.1 Place the long sides of the specimen centrally in the clamps with the bottom edge carefully set against the stops and the
upper edge parallel to the top of the clamps. Close the clamps, securing the specimen with approximately the same tension on both
clamps. The specimen should lie free with its upper area directed toward the pendulum to ensure a shearing action.
10.3.2 Using the built-in knife blade cut a 20 mm (0.787 in.) slit in the specimen extending from the bottom edge and leaving a
balance of fabric 43.0 6 0.15 mm (1.69 6 0.005 in.) remaining to be torn.
10.4 For Die-Cut or Manually Slit Specimens:
10.4.1 If a die without a slit is used, manually cut a 20 mm (0.787 in.) long slit in the center of one edge of the long direction
of the specimen. Ensure that the balance of the fabric remaining to be torn is 43 6 0.15 mm (1.69 6 0.005 in.).
NOTE 5—The length of the cut is important, see Note 3.
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10.4.2 Place the parallel, unslit sides of the specimen in the clamps with the bottom edge carefully set against the stops, the upper
edge parallel to the top of the clamp and the slit centrally located between the clamps. Close the clamps, securing the specimen
with approximately the same tension on both clamps. The specimen should lie free with its upper area directed toward the
pendulum to ensure a shearing action.
10.5 For Wet Specimen Testing:
10.5.1 Remove a specimen from the water and immediately mount it on the testing machine in the normal set-up. Perform the test
within 2 min after removal of the specimen from the water. Otherwise, discard the specimen and replace with another one.
10.6 Depress the pendulum stop downward to its limit and hold it until the tear is completed and the pendulum has completed its
forward swing. Catch the pendulum just after the threshold of its backward swing and return to its locked starting position. When
equipped, be careful not to disturb the position of the pointer. Record the scale reading required to completely tear the test
specimen.
10.6.1 The decision to discard the results of a tear shall be based on observation of the specimen during a test and upon the
inherent variability of the material. In the absence of other criteria, such as in a material specification, if an unusual cause is
detected, the value may be discarded and another specimen tested.
10.6.2 Reject readings obtained where the specimen slips in the jaw or where the tear deviates more than 6 mm (0.25 in.) away
from the projection of the original slit. Note when puckering occurs during the test.
10.6.3 For microprocessor systems, follow the manufacturer’s directions for removing values from memory when the decision to
discard a tear value has been made. Otherwise, for some test instruments manual calculation of the average is required.
10.6.4 If, during the test, the scale reading does not reach 20 % or reaches over 80 % (60 % when applicable, see Table A3.1) of
full scale range
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