Overview
EN ISO 16047:2005/A1:2012 - Fasteners: Torque/clamp force testing is an amendment to ISO 16047:2005 adopted by CEN (approved 14 September 2012). It updates the international test standard for measuring torque and resulting clamp (preload) force on metric threaded fasteners (thread sizes M3 to M39) whose mechanical properties are specified in ISO 898-1 or ISO 898-2. The amendment clarifies scope language, updates normative references, and adjusts specified terminology (for example, removing references to ISO 898-6 and self‑locking fastener wording).
Key topics and requirements
- Scope refinement: Applies to fasteners with mechanical properties defined in ISO 898-1 or ISO 898-2 and to metric thread sizes M3–M39. References to ISO 898-6 and to “additional self-locking features” were removed in the amendment.
- Normative references: ISO 898-6 reference deleted; primary mechanical-property references are ISO 898-1 and ISO 898-2.
- Terminology and table corrections: Amendment updates table entries (e.g., the definition of proof load Fp now references ISO 898-1 or ISO 898-2, whichever is relevant).
- Test focus: Standard governs how to relate applied torque to resulting clamp (preload) force for fasteners, and how to document and interpret those measurements in conformity testing and quality control (without prescribing any unlisted test apparatus specifics).
Applications
- Quality control and production testing of bolts and screws where accurate torque-to-preload relationships are critical.
- Validation of assembly procedures to ensure correct clamp force during manufacture or maintenance.
- R&D and material/fastener performance characterization for engineering design and safety assessments.
- Supplier qualification and incoming inspection to verify fastener mechanical behavior against specified classes.
Who uses this standard
- Fastener manufacturers and suppliers for product testing and specification compliance.
- Test laboratories performing torque and clamp force measurements.
- Design, assembly and quality engineers in automotive, aerospace, machinery, construction and industrial manufacturing.
- Procurement and inspection teams ensuring supplied fasteners meet mechanical and performance criteria.
Related standards
This EN ISO 16047 amendment is an essential reference for organizations that need standardized procedures and terminology for torque testing, clamp force measurement, and related fastener performance verification.
