Overview - EN ISO 9513:2012 (Calibration of extensometer systems)
EN ISO 9513:2012 specifies a method for the static calibration of extensometer systems used in uniaxial testing of metallic materials. The standard covers both axial and diametral extensometers, and addresses contacting and non‑contacting systems (including laser and video extensometry / digital image correlation). Its core principle is a direct comparison of extensometer readings with known length changes produced by a calibrated calibration apparatus, providing traceable, documented calibration and performance classification.
Key topics and technical requirements
- Scope and definitions: clear definitions of extensometer system, gauge length and symbols used in calibration.
- Calibration principle: compare extensometer output with known displacements from a calibration apparatus (static calibration).
- Calibration equipment & traceability: requirements for calibration apparatus and traceability to national/international standards.
- Pre‑calibration inspection: visual/functional checks and identification of extensometer system elements before calibration.
- Gauge length measurement: procedures for fixed, variable and non‑contacting gauge lengths and for setting gauges.
- Calibration process: environmental considerations, extensometer positioning, selection of calibration increments and data acquisition.
- Data analysis & classification: methods to determine bias, resolution, relative errors and to classify extensometer system performance.
- Uncertainty: guidance and an uncertainty budget framework for determining measurement uncertainty (informative Annex A).
- Calibration intervals & reporting: recommendations for calibration intervals and mandatory information for the calibration certificate (data presentation, results).
- Informative annexes: examples and guidance including calibration of calibration apparatus, sample reports, configurations and techniques (laser, video, full‑field, crosshead measurement).
Practical applications and users
EN ISO 9513 is used by:
- Materials testing and tensile testing laboratories performing uniaxial testing of metals.
- Calibration and metrology laboratories that provide extensometer calibration and traceability services.
- Manufacturers of extensometers and measurement systems (contacting and non‑contacting).
- Quality managers, R&D teams and certification bodies requiring documented, traceable strain measurement for material characterization, fatigue testing, product validation and compliance with test methods.
Practical benefits:
- Ensures consistent, traceable strain/displacement readings for tensile and diametral tests.
- Enables reliable comparison of test data across labs and projects.
- Supports compliant calibration certificates and uncertainty statements used for quality control and accreditation.
Related standards
- EN ISO 9513 complements other ISO/CEN standards on mechanical testing of metals and laboratory calibration best practices. For traceability and testing workflows, use it alongside relevant mechanical testing and calibration standards.
