ISO 12625-4:2016 specifies a test method for the determination of the tensile strength, stretch at maximum force and tensile energy absorption of tissue paper and tissue products. It uses a tensile-testing apparatus operating with a constant rate of elongation.It also specifies the method of calculating the tensile index and the tensile energy absorption index.In cases where impurities and contraries have to be determined, ISO 15755[6] applies for these detections in tissue paper and tissue products.