This Part of EN ISO 13937 describes a double-tear method known as the tongue test, using a test specimen with cuts shaped to form a tongue. The tear force measured is the force required to propagate the previously started double tears when the force is applied parallel to the cuts and the fabric tears in the direction of the applied force. The test is mainly applicable to woven textile fabrics. It may be applicable to fabrics produced by other techniques, e.g. to some nonwovens (with the same under-mentioned restrictions as for the woven fabrics). In general the method is not applicable to knitted fabrics and woven elastic fabrics. 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 trouser test and part 3 a wing test method. Part 1 of EN ISO 13937 describes the ballistic pendulum (Elmendorf) method. NOTE 2: For the trapezoidal test methods see ISO 9073-4 for nonwovens or ISO 4674 for coated fabrics.
GSO ISO 13937-4:2012 history
2012GSO ISO 13937-4:2012 Textiles - Tear properties of fabrics - Part 4 : Determination of tear force of tongue-shaped test specimens (Double tear test)