ISO 12625-4:2022

Overview

ISO 12625-4:2022 specifies a tensile test method for tissue paper and tissue products. The standard defines how to measure tensile strength, stretch at maximum force, and tensile energy absorption (TEA) using a tensile-testing apparatus operating at a constant rate of elongation. It also gives procedures to calculate the tensile index and the tensile energy absorption index. Annex B (new in this edition) provides an optional method for determining tensile modulus; precision data are in Annex A.

Key topics and requirements

• Test principle: stretch a calibrated test piece to break while recording force vs. elongation; integrate the area under the curve to obtain TEA.
• Apparatus: tensile tester compliant with ISO 1924-2 and ISO 7500-1 for force calibration; means to measure area of the force–elongation curve to ±2% accuracy.
• Rate of elongation: 50% of initial span per minute (e.g., 50 mm/min for a 100 mm span; 25 mm/min for a 50 mm span).
• Start of elongation measurement: at a force of (0.25 ± 0.05) N (slack correction applied).
• Force accuracy: load cell accuracy of ±1% of reading or ±0.025 N, whichever is greater.
• Clamps and span: clamps at least 50 mm wide, clamping lines parallel within 1°; standard test span (100 ± 1) mm, or (50 ± 1) mm for small finished products.
• Test-piece dimensions: 50.0 ± 0.5 mm width and at least 150 mm length (shorter permitted for some finished products with corresponding span adjustments).
• Sampling and conditioning: condition samples per ISO 187; select representative samples per ISO 186.
• Sample count: minimum 10 test pieces in machine direction and 10 in cross direction (total ≥20).
• Calculations: tensile strength, tensile index (tensile strength ÷ grammage), stretch at maximum force (percentage), TEA and TEA index (TEA ÷ grammage).
• Reporting: include test conditions, apparatus details, span, number of test pieces and calculated indices.

Applications and users

ISO 12625-4:2022 is used for quality control, product development, specification compliance and comparative testing of tissue grades and finished tissue products. Typical users:

• Tissue manufacturers and converters (product R&D, process control)
• Third‑party testing laboratories and QA departments
• Raw material suppliers and formulators assessing strength and softness trade-offs
• Procurement and compliance teams specifying mechanical performance
• Standards bodies and regulatory organizations

Related standards

• ISO 1924-2 (tensile properties - constant rate of elongation)
• ISO 187 (conditioning and testing atmosphere)
• ISO 186 (sampling)
• ISO 7500-1 (calibration of tension machines)
• ISO 12625-1 (vocabulary) and ISO 12625-6 (grammage determination)

Keywords: ISO 12625-4:2022, tissue paper tensile test, tensile strength, tensile energy absorption, tensile index, stretch at maximum force, tissue products testing.