Overview
EN ISO 22705-1:2025 - adopted by CEN from ISO 22705-1:2021 - defines the measurement and test parameters for cold formed cylindrical helical compression springs made from round wire. The standard covers methods to measure general geometric and mechanical characteristics (for example free length, diameters, coil count and spring load) and sets out conditions for testing, required equipment and personnel qualifications. Dynamic testing is explicitly excluded.
Keywords: EN ISO 22705-1:2025, springs, cold formed cylindrical helical compression springs, measurement and test parameters, ISO 22705-1:2021, spring testing.
Key topics
The standard provides detailed guidance on:
- Scope and normative references - clarifies applicability to technical cold-formed helical compression springs.
- Terms, symbols and definitions - consistent terminology for test results and reporting.
- Environmental conditions and qualifications of personnel performing measurements and tests.
- Measuring and testing equipment - types and conditions for accurate measurement.
- Measurement/test parameters for critical spring features, including:
- Free length (L0)
- Outside diameter (De) and inside diameter (Di)
- Total and active number of coils (nt, n) and coil direction
- Applied end coils and ground surface/angle
- Solid length (Lc) and solid force (Fc)
- Spring load (F) at specified compressions
- Pitch / distance between coils (p)
- Perpendicularity and other geometric tolerances
- Test locations on the product, measurement methods and conditions for repeatable results.
Practical applications
EN ISO 22705-1:2025 is practical for:
- Spring manufacturers - process control, production inspection and acceptance testing.
- Quality assurance teams - establishing inspection procedures and specification conformance.
- Test laboratories - standardised methods for inter-lab comparability and traceable results.
- Design and R&D engineers - validating dimensional and load characteristics against design requirements.
- Procurement and suppliers - specifying measurement and test parameters in purchase orders and contracts.
Using the standard helps reduce disputes, ensures consistent measurement practices, and improves interchangeability and performance verification of compression springs.
Related standards
- This document is Part 1 of the ISO 22705 series (EN ISO 22705-1:2025 corresponds identically to ISO 22705-1:2021).
- Users should consult other parts of the ISO 22705 series and relevant national/industry standards where dynamic testing, materials specifications or special spring types are required.
