ISO 12625-5 is an ISO test method for determining the wet tensile strength of tissue paper and tissue products after soaking with water. It is commonly used to evaluate how well tissue materials retain strength when wet for product development, quality control, and supplier qualification.
This standard is frequently referenced when comparing wet-strength performance across tissue grades, converting conditions, or chemistry changes (for example, wet-strength resins). If you need help aligning your lab setup to the vertical or horizontal approach described in the standard, talk with our team.
ISO 12625-5: Tissue paper and tissue products — Determination of wet tensile strength
ISO 12625-5 defines a standardized way to measure wet tensile strength for tissue paper and finished tissue products after water soaking, using a constant-rate-of-elongation tensile tester. The method supports both commercially used configurations where the test piece is oriented vertically or horizontally during wetting and testing.
Quick definition
Document type: Test method (wet tensile strength of tissue).
What it measures: Tensile strength of a tissue specimen in a wet condition after soaking with water.
Typical output: Wet tensile strength values used for QC trending, grade comparisons, and performance targets.
What this standard covers
ISO 12625-5 focuses on preparing a tissue test piece, wetting it in a controlled way, and pulling it to failure on a tensile tester operating at a constant rate of elongation. The scope is specifically wet tensile strength for tissue paper and tissue products and does not cover impurity/contrary determination.
The standard recognizes two common equipment layouts used in the industry: (1) a vertical tensile setup that wets the specimen using a dedicated cup-style wetting device held in the lower grip (often referred to as a Finch cup), and (2) a horizontal tensile setup that uses a soaking device placed between the clamps.
Why this standard matters in testing
Wet tensile strength is a key performance attribute for many tissue products where the sheet must maintain integrity in contact with water. ISO 12625-5 helps labs generate comparable results across shifts, sites, and suppliers by standardizing the wetting approach and the tensile test configuration.
From an equipment standpoint, repeatability often depends less on peak force capacity and more on low-force measurement quality, specimen handling, and consistent wetting timing and alignment.
Common materials, product types, or applications covered
ISO 12625-5 is used for tissue base papers and converted tissue products where wet strength is a functional requirement or a monitored quality characteristic.
Common product areas: Bathroom tissue, household towels, facial tissue, napkins, and other tissue-based products where wet handling performance is important.
Common test or verification workflow
Most labs use ISO 12625-5 as part of a broader tissue performance verification plan that includes dry tensile and other physical properties.
- Condition and prepare test pieces per the standard’s requirements.
- Soak/wet the specimen using a controlled wetting device appropriate to the tester orientation (vertical or horizontal setup).
- Perform a constant-rate-of-elongation tensile pull to determine the wet tensile strength.
- Report results in the format required by your internal specification, customer requirement, or purchase agreement, using the same edition of the standard across all parties.
Equipment commonly used for this standard
ISO 12625-5 is typically run on a universal tensile testing platform configured for low-force paper/tissue work, with grips and accessories designed to handle thin, compliant specimens and a controlled wetting step.
Common equipment: Constant-rate-of-elongation tensile tester (universal testing machine), low-capacity load cell suitable for tissue forces, tissue/paper grips or clamps sized for the specimen geometry, and a wetting/soaking device matched to the tester layout.
Wetting accessories: Vertical systems commonly use a cup-style wetting device held in the lower grip (often called a Finch cup). Horizontal systems commonly use a soaking device positioned between the clamps to wet the specimen consistently before loading.
Practical configuration notes: For purchasing or upgrading a system, key decisions usually include load cell range, grip type and alignment control, wetting accessory compatibility (vertical vs horizontal approach), and software reporting needed for your QC workflow. If you are comparing fixtures or wetting accessories for your current frame, you can request a detailed quote for a configuration matched to your setup.
How to read this designation or revision
Designation format: ISO 12625-5 identifies the ISO 12625 series and “Part 5” within that series.
Year suffix: When cited with a year (for example, ISO 12625-5:2024), the year indicates the specific published edition being used. Because equipment setup details and reporting expectations can vary by edition, match the exact cited year in contracts, customer specifications, or internal SOPs.
Related standards, methods, or frameworks
ISO 12625-5 is often paired with dry tensile testing of tissue to understand wet vs dry performance and to support troubleshooting when converting or chemistry changes affect strength.
Common companion reference: ISO 12625-4 (tensile strength, stretch at maximum force, and tensile energy absorption for tissue paper and tissue products) is frequently used alongside ISO 12625-5 in tissue test programs.
Talk with us about ISO 12625-5 testing setups
If you are setting up wet tensile testing for tissue or updating an older method to match the edition cited by a customer, contact our team to review fixture orientation (vertical vs horizontal), wetting accessories, and a practical equipment configuration for your sample types.