ASTM D 5733 : 1999

1.1 This test method covers the measurement of the tearing strength of nonwoven fabrics by the trapezoid procedure using a recording constant-rate-of-extension (CRE) tensile testing machine.

1.1.1 The CRE-type tensile testing machine has become the preferred test apparatus for determining trapezoid tearing strength. It is recognized that some constant-rate-of-traverse (CRT) tensile testing machines continue to be used. As a consequence, these test instruments may be used when agreed upon between the purchaser and the supplier. The conditions for the CRT-type tensile tester as used with this test are included in Appendix X1.

1.2 This test method applies to most nonwoven fabrics including those that are treated or untreated, heavily sized, coated, or resin-treated. This test method may not be useful for highloft nonwoven fabrics.

1.3 Trapezoid tear strength as measured in this test method is the maximum tearing force required to continue or propagate a tear started previously in the specimen. The reported value is not directly related to the force required to initiate or start a tear.

1.4 The values stated in SI units are to be regarded as the standard. The inch-pound units given in parentheses 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 and health practices and determine the applicability of regulatory limitations prior to use.