ISO 12625-5:2016 specifies a test method for the determination of the wet tensile strength of tissue paper and tissue products after soaking with water, using a tensile-strength-testing apparatus operating with a constant rate of elongation.

Currently, two types of tensile-strength-testing apparatus are commercially available, one where the test piece is positioned vertically and, for the other, horizontally. This document applies for both. For vertical tensile-strength-testing apparatus, a device which is held in the lower grip of the tensile-strength-testing apparatus, called a Finch Cup, is used to achieve the wetting. For horizontal tensile-strength-testing apparatus, the soaking device is placed between the clamps.

In cases where impurities and contraries have to be determined, ISO 15755[6] applies for these detections in tissue paper and tissue products.