Overview
EN ISO 1974:2012 - Paper: Determination of tearing resistance - Elmendorf method specifies a standardized laboratory method for measuring the out-of-plane tearing resistance of paper using the Elmendorf pendulum tear tester. The standard covers test principle, apparatus requirements, sampling, conditioning, preparation of test pieces, calibration, procedure, calculation of tearing resistance and tear index, and reporting. It applies to paper and low‑grammage boards (within instrument range), but not to corrugated fibreboard (components may be tested). It is not suitable for measuring cross‑direction tearing on highly directional papers.
Key topics and technical requirements
- Test principle: An initial cut is made in a pack of four superimposed sheets; a pendulum tears the pack out-of-plane and the energy loss of the pendulum is used to calculate mean tearing force per sheet.
- Apparatus: Elmendorf‑type tear tester with:
- Pendulum(s) of suitable capacity (recommended capacities include 2 000, 4 000, 8 000, 16 000 mN).
- Catch, stationary frame, and two clamping jaws (clamping widths typically 25 mm or 36 mm).
- Optional cutting knife adjusted to give a tearing length of (43.0 ± 0.5) mm.
- Means for registering pendulum swing or direct force reading.
- Test pieces and dimensions: Four rectangular sheets cut from conditioned sample; sheet width depends on clamp size (≈50 mm or 76 mm).
- Sampling and conditioning: Follow ISO 186 for sampling and ISO 187 for standard atmosphere and conditioning. Tests are sensitive to moisture - handle and store samples carefully.
- Results:
- Tearing resistance reported in millinewtons (mN).
- Tear index = tearing resistance / grammage (expressed in mN·m²/g).
- Calibration and precision: The standard includes requirements for adjustment, calibration, and informative precision data (repeatability and reproducibility).
Applications and users
- Practical uses:
- Quality control and acceptance testing in paper mills and converting plants.
- R&D for paper product development where tear resistance is a critical property (e.g., printing papers, packaging papers, label stock).
- Supplier and buyer specification verification, comparative material evaluation, and process troubleshooting.
- Typical users:
- Laboratory technicians, QC managers, test laboratories, product engineers, and standards specialists in the pulp and paper industry.
Related standards
- ISO 186 - Paper and board: Sampling to determine average quality
- ISO 187 - Standard atmosphere for conditioning and testing
- ISO 536 - Determination of grammage
Keywords: EN ISO 1974:2012, Elmendorf method, tearing resistance, tear index, Elmendorf tear tester, paper testing, tear test, paper standards, sampling, conditioning.
