This Part of EN ISO 13937 describes a single tear method to determine fabric tear force, known as the wing test using a test specimen cut to form two wings for clamping inclined at a defined angle to the thread direction. The tear force measured is the force required to propagate a previously started tear.
The test is mainly applicable to woven textile fabrics. It may be applicable to fabrics produced by other techniques. Due to the clamping of the specimen wings inclined to the threads to be torn the test can be used for most types of fabrics without causing a transfer of tear and it is less susceptible to withdrawal of threads than other tear tests.
In general the method is not applicable to knitted fabrics, woven elastic fabrics and nonwovens, to which the trapezoidal test method is preferably applied (Note 2).
The method only allows the use of constant-rate-of-extension (CRE) testing machines.
NOTE 1: For other tear test methods using tensile-testing machines part 2 of EN ISO 13937 describes a method known as the trouser test and part 4 the tongue test method. Part 1 of EN ISO 13937 describes the ballistic pendulum (Elmendorf) method.
NOTE 2: For trapezoidal test methods, see ISO 9073-4 for nonwovens or ISO 4674 for coated fabrics.