ISO 16063-21:2003

Overview - ISO 16063-21:2003 (Vibration calibration by comparison to a reference transducer)

ISO 16063-21:2003 specifies methods for the calibration of rectilinear vibration transducers by comparison to a reference (secondary) transducer. The standard is intended mainly for laboratory calibrations but is also applicable in the field. It covers procedures to determine the magnitude and, optionally, the phase shift of the complex sensitivity of vibration transducers in the nominal frequency range 0.4 Hz to 10 kHz (systems have been demonstrated from 0.01 Hz to 30 kHz). The document emphasizes traceability, documented measurement uncertainty, and practical calibration arrangements (back-to-back or in-line mounting).

Key topics and technical requirements

• Scope and transducer type: Applies to rectilinear vibration transducers (with or without signal conditioning).
• Calibration method: Direct comparison to a reference transducer; methods may be applied between other levels in the calibration hierarchy (primary → reference → working/check standards).
• Frequency & dynamic ranges: Nominal 0.4 Hz–10 kHz (with notes on optional ranges and single-point calibrations); frequency-dependent dynamic ranges and practical limits (noise floor, exciter distortion).
• Uncertainty of measurement: Mandatory uncertainty budgets per Annex A; examples provided for two system classes (Example 1 - well-controlled lab; Example 2 - less stringent conditions). Representative expanded uncertainties (coverage factor k=2) from the standard:
  • Accelerometers 0.4 Hz–1 kHz: Example 1: 1%, Example 2: 3% (magnitude)
  • Accelerometers 1 kHz–2 kHz: 2% / 5%
  • Accelerometers 2 kHz–10 kHz: 3% / 10%
  • Displacement/velocity transducers 20 Hz–1 kHz: 4% / 6%
  • Phase shift at reference conditions: 1° / 3° (Example 1 / 2)
• Apparatus & environment: Reference transducer preferably calibrated with amplifier; recommended room temperature and humidity tolerances (Example 1: 23 ±5 °C, humidity ≤75%; Example 2: 23 ±10 °C, humidity ≤90%).
• Documentation and reporting: Procedures for measurement, expression of results, and reporting are specified; Annexes provide uncertainty calculation examples, definitions of amplitude/phase sign, and nomograms.

Applications and practical value

• Provides a standardized, traceable method for accelerometer calibration, vibration sensor verification, and transfer of calibration between standards.
• Used by metrology laboratories, calibration service providers, R&D test labs, and maintenance/quality engineers who require documented measurement traceability and uncertainty evaluation.
• Applicable for laboratory-grade calibrations where low uncertainty is required and for field calibrations using portable check standards (with expected larger uncertainties).

Related standards

• ISO 16063 series (relevant parts): Part 1 (Basic concepts), Part 11 (Primary calibration by laser interferometry), Part 12 (Reciprocity), Part 13 (Primary shock calibration), Part 22 (Shock calibration by comparison).
• Guide to the expression of uncertainty in measurement (GUM) - referenced for uncertainty methods.

Keywords: ISO 16063-21:2003, vibration calibration, reference transducer, calibration by comparison, accelerometer calibration, measurement uncertainty, vibration transducers, rectilinear vibration.