Secure the specimen in the grips and pull at the specified speed (typically for standard dumbbells).

Temperature must be maintained (standard: 23 ± 2°C). Comparison: JIS K 6251 vs. ISO 37

The increase in length at the moment of breakage, expressed as a percentage of the original length.

Standards change. Set a calendar reminder to check JSA’s website every May for any new revisions to .

This version (often searched as a PDF) is based on the international standard ISO 37:2011 , incorporating modifications tailored to the Japanese industry.

While globally harmonized to a degree, critical differences exist between the major regional rubber testing standards: JIS K 6251 Japan / Asia International / Europe North America Standard Speed 500 mm/min 500 mm/min 500 mm/min Specimen Geometry Types 1 to 6 Dumbbells Types 1 to 4 & Die C Die A to F Dumbbells Thickness Limits Typically 2.0 mm 2.0 mm default 1.5 mm to 3.0 mm

Standard sizes used for general rubber testing.

Testing typically follows general procedures for preparation, marking, and conditioning as specified in JIS K 6250 . Standard Evolution & PDF Availability

Test a reference rubber (e.g., NR vulcanizate with known tensile strength of 25 MPa). Your results should fall within ±5% of the certified value per JIS K 6251.