Overview
EN ISO 10321:2008 - Geosynthetics - Tensile test for joints/seams by wide‑width strip method (ISO 10321:2008) defines an index laboratory method to measure the tensile properties of joints and seams in geosynthetics using a wide‑width strip specimen. The standard applies to most geosynthetics (including geogrids with modified specimen dimensions) but excludes polymeric or bituminous geosynthetic barriers. Results quantify joint/seam tensile strength and allow calculation of joint or seam efficiency versus the unjointed material (referencing ISO 10319).
Key topics and technical requirements
- Specimen geometry: nominal specimen width 200 mm; initial jaw separation = 100 mm + seam/joint width; 25 mm extensions either side of the seam for stability.
- Number of tests: cut and test at least five specimens (plus five additional if wet testing required).
- Conditioning:
- Standard atmosphere per ISO 554: 20 °C ± 2 °C and 65 % RH ± 5 % RH.
- Wet conditioning: immersion in water at 20 °C ± 2 °C for at least 24 hours; up to 0.05 % non‑ionic wetting agent permitted.
- Test machine and clamps:
- Constant rate of extension tensile machine complying with ISO 7500‑1, Class 2 or higher.
- Jaw faces at least 200 mm wide; use wedge jaws, compressive block jaws or capstan grips to limit slippage and damage.
- Test parameters:
- Strain rate that produces (20 ± 5) %/min in gauge length.
- Record maximum force to 0.01 kN accuracy.
- Results & reporting:
- Report maximum joint/seam strength (kN/m), failure mode (material break, sewing thread break, joint failure, slippage, etc.), and joint/seam efficiency (%) relative to tensile strength from ISO 10319.
- Include conditioning details, specimen orientation and failure observations.
Applications and users
EN ISO 10321:2008 is used for:
- Product performance verification by manufacturers of geotextiles, geogrids and sewn or welded geosynthetics.
- Independent testing laboratories performing QA/QC and type testing.
- Designers, specifiers and contractors needing reliable joint/seam strength data for containment, drainage, reinforcement and lining systems.
- Regulatory bodies and project engineers requiring documented seam performance for safety and compliance.
Practical benefits: enables comparison of seam methods (sewing, welding, mechanical joints), informs construction tolerances, and supports specification of joint efficiency in design.
Related standards
- ISO 10319 - Wide‑width tensile test (unjointed material baseline)
- ISO 10318 - Geosynthetics terms and definitions
- ISO 9862 - Sampling and preparation of test specimens
- ISO 554 - Standard atmospheres for conditioning
- ISO 3696 - Water for analytical use
- ISO 7500‑1 - Verification of tensile testing machines
Keywords: EN ISO 10321:2008, geosynthetics tensile test, wide‑width strip method, joint seam strength, joint efficiency, geogrids testing, conditioning, tensile testing machine.
