Overview
ISO 21180:2025 specifies a standardized test method for the determination of the maximum tensile strength of light conveyor belts (in accordance with ISO 21183-1) or other belts where ISO 283 does not apply. The standard defines the principle, required apparatus, specimen preparation, test-room and conditioning requirements, test procedure, calculation of results and minimum reporting elements.
This edition was prepared by ISO/TC 41 in cooperation with CEN/TC 188 and includes the addition of explicit test room condition requirements.
Key Topics
- Principle: record tensile force as a function of belt elongation on a longitudinal, full-thickness test piece and extract the maximum tensile force.
- Apparatus: use a tensile testing machine with a force-measuring system compliant with ISO 7500-1 (machine class 3 or better).
- Test pieces: cut from full belt thickness in the longitudinal direction; five specimens selected across the belt width; datum marks 100 ± 0.5 mm apart on the longitudinal axis.
- Conditioning: condition specimens per ISO 18573 (Atmosphere B) for 24 h; extend to 48 h for high moisture‑absorbing materials (e.g., cotton, polyamide).
- Test room conditions: temperature 23 °C ± 2 °C and relative humidity 50 % ± 5 %.
- Procedure: set free length between jaws to 220 mm ± 5 mm, apply continuous tensile loading at (100 ± 10) mm/min, record force vs elongation, stop at maximum force or at break.
- Calculation: maximum tensile strength k_max = F_max / width (use smallest width, typically 25 mm); elongation at F_max may be calculated from measured Δl or from Δl/220 when Δl device not available (noting limitations).
- Test report: include belt designation and manufacture date, reference to ISO 21180:2025, test-room conditions, conditioning period, results, deviations and observations.
Applications
This test method provides practical value for:
- Quality control: verify batch-to-batch consistency of light conveyor belts.
- Material selection: compare constructions and materials when defining belt specifications.
- Acceptance testing: provide objective criteria for procurement and supplier acceptance.
- R&D and product development: evaluate the tensile behavior of new belt designs or coatings.
The standardized procedure helps reduce variability from specimen handling, conditioning and machine calibration, improving comparability of tensile strength data across laboratories and suppliers.
Related Standards
Key referenced and related standards include:
- ISO 7500-1 - calibration and verification of tension/compression testing machines
- ISO 18573 - conveyor belts: test atmospheres and conditioning periods
- ISO 283 - full-thickness tensile test for textile conveyor belts (when applicable)
- ISO 1421 and ISO 13934-1 - alternative specimen shapes and fabric/ coated-fabric tensile methods
- ISO 21183-1 - principal characteristics and applications of light conveyor belts
By aligning testing and reporting to ISO 21180:2025, stakeholders gain reproducible tensile-strength data to inform specification, compliance and product performance decisions.
