ISO 12625-5:2024

Overview

ISO 12625-5:2024 specifies a laboratory test method for determining the wet tensile strength of tissue paper and tissue products after soaking with water. The method uses a tensile-strength-testing apparatus operating at a constant rate of elongation and applies to both commercially available vertical and horizontal testing configurations. For vertical testers a Finch Cup soaking device is used; for horizontal testers a soaking device is placed between the clamps. The standard also defines wet‑tensile‑strength retention (wet strength as a percentage of dry conditioned strength) and sets requirements for measurement accuracy, conditioning, preparation, calculation and reporting.

Key topics and technical requirements

• Test principle: soak a test piece, then stretch to break at a constant rate of elongation and record tensile force vs. elongation.
• Rate of elongation: (50 ± 2) mm/min (constant rate).
• Force measurement: load cell accuracy ±1% of reading or ±0.025 N, calibrated per ISO 7500-1.
• Apparatus types:
  • Vertical tensile-strength-testing apparatus: uses a Finch Cup soaking device mounted in the lower clamp; specified span lengths and clamp geometry.
  • Horizontal tensile-strength-testing apparatus: soaking device inserted between clamps; removable table and parallel clamping lines required.
• Clamps: smooth, rounded edges, minimum widths and adjustable clamping force to prevent slippage or damage.
• Sample preparation and conditioning: aligned with ISO 187 for standard atmosphere and conditioning; guidance on dimensions, number of test pieces and accelerated ageing (curing) terminology.
• Calculations and reporting: wet tensile strength (N/m), wet-tensile-strength retention (%), and precision data provided in Annex A.
• Scope limitation: not applicable where impurities or contraries are being determined.

Applications and users

ISO 12625-5 is used for:

• Quality control and batch acceptance testing in tissue manufacturing.
• Product development and R&D to compare wet strength formulations, treatments or converting processes.
• Supplier and customer specifications for tissue paper, facial tissue, toilet tissue, kitchen towels and other tissue products.
• Laboratory accreditation, inter‑laboratory comparisons and compliance testing. Primary users include quality engineers, laboratory technicians, product developers, standards bodies, testing laboratories and equipment manufacturers/suppliers.

Related standards

• ISO 1924-2 - tensile testing (constant rate of elongation)
• ISO 7500-1 - calibration of force-measuring systems
• ISO 187 - conditioning and atmosphere for testing
• ISO 12625-1 - vocabulary for tissue paper and products
• ISO 186 - sampling to determine average quality

Keywords: ISO 12625-5, wet tensile strength, Finch Cup, tissue paper testing, tensile-strength-testing apparatus, wet-tensile-strength retention, ISO standards.