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.
