Overview
EN ISO 22705-2:2025 - adopted from ISO 22705-2:2023 - defines measurement and test methods for cold formed cylindrical helical extension springs made from round wire. Published by CEN in October 2025, this European Standard sets out how to measure general geometric and static characteristics of extension springs (for example free length, body length, hook dimensions, diameters and spring load). Dynamic testing is explicitly excluded from this part. The document also covers environmental conditions, required equipment, and operator qualifications to ensure consistent, reproducible results.
Key topics and requirements
This standard provides standardized procedures and acceptance-focused parameters for spring measurement and testing, including:
- Measured characteristics: free length (L0), body length (LB), spring hook length (LH), hook opening (m), outside diameter (De), inside diameter (Di), coil counts and direction, bending radius, spring pitch/distance between coils, and static spring load (F).
- Measurement methods: specified instruments and fixtures, guidance on guiding/support device geometries, and step-by-step measurement procedures to reduce variation.
- Testing conditions: required environmental conditions (temperature/humidity), preconditioning and test setup rules, and the locations on the product where measurements are to be taken.
- Personnel and equipment: minimum qualifications for persons performing tests and descriptions of measuring and testing equipment to achieve traceable, repeatable results.
- Exclusions: dynamic or fatigue testing methods are not covered in this part.
Practical applications and users
EN ISO 22705-2:2025 is aimed at professionals involved in the design, manufacture, inspection and procurement of extension springs:
- Spring manufacturers - for process control, in-process checks and final acceptance testing.
- Quality engineers and test laboratories - to perform standardized dimensional and static load verification and produce reproducible test reports.
- Design engineers - to validate tolerances, mating features and assembly interfaces.
- Purchasers and specifiers - to write clear, unambiguous procurement specifications that reference standard measurement methods.
- Certification and compliance bodies - to harmonize national requirements across CEN member countries.
Using this standard reduces measurement disputes, improves interchangeability and supports consistent quality control across supply chains for cold formed cylindrical helical extension springs.
Related standards
- EN ISO 22705-2:2025 is part of the ISO/CEN work on spring measurement parameters. Refer to other parts of the ISO 22705 series and national CEN adoptions for complementary guidance on different spring types and dynamic testing (where applicable).
Keywords: EN ISO 22705-2:2025, cold formed cylindrical helical extension springs, measurement and test parameters, spring testing, spring dimensions, spring load, CEN, ISO 22705-2:2023.
