ISO 16063-16:2014

Overview

ISO 16063-16:2014 - Methods for the calibration of vibration and shock transducers - Part 16: Calibration by Earth's gravitation - defines a primary calibration method for accelerometers that uses the local acceleration of gravity. It applies to rectilinear, DC-response accelerometers such as strain-gauge, piezoresistive, variable-capacitance and servo types. The standard specifies required instrumentation, environmental conditions, measurement procedures and uncertainty evaluation for calibrating the magnitude of sensitivity (at 0 Hz) referenced to local g. With suitable equipment the method also supports calibration at fractional parts of g.

Key topics and technical requirements

• Scope and applicability: Primary sensitivity calibration for DC accelerometers and reference/working standards.
• Measurement principle: Rotate the accelerometer between orientations relative to the gravity vector (0°/180° or fractional angles) and compute sensitivity from measured DC output voltages and the known acceleration due to gravity.
• Essential instrumentation:
  • Mounting platform capable of rotating the sensor axis from 0° to 180°, with angle accuracy ±0.1° at measurement positions.
  • DC voltage measuring instrument with frequency range down to 0 Hz and maximum uncertainty of 0.05% of reading.
  • Means to determine local g (absolute/relative gravimeter or geodetic formula).
• Environmental conditions: Recommended ambient temperature (23 ± 3) °C and relative humidity ≤ 75% RH; minimise external vibration and noise.
• Formulas and procedures:
  • 0°/180° method: S = (u0 − u180) / (2·g)
  • Fractional gravity method: uses four orientation measurements and the factor cos(θ) to calibrate at g·cos(θ).
  • Preferred fractional angles: ±30°, ±45°, ±60° (cosine values 0.866, 0.707, 0.5).
• Uncertainty of measurement (UoM):
  • Users must prepare an uncertainty budget per Annex A.
  • When local g is known, expanded uncertainty around 0.1% is achievable; using the standard g without local correction, an expanded uncertainty around 0.5% is indicated (document details component contributions: g accuracy, voltage measurement accuracy/resolution, transverse sensitivity, misalignment, environmental effects, etc.).
• Reporting: Report ambient conditions, value for g used, raw voltages, calculated sensitivity and expanded uncertainty (coverage factor k, typically 2).

Practical applications and users

ISO 16063-16 is used by:

• National metrology institutes and calibration laboratories performing primary accelerometer calibration.
• Manufacturers of accelerometers and vibration transducers validating DC sensitivity.
• Quality and test labs in aerospace, automotive, civil engineering and seismic instrumentation where accurate low-frequency/ static acceleration sensitivity is required. Benefits include traceability to local gravity, a documented uncertainty budget, and standardized reporting for calibration certificates.

Related standards

ISO 16063 series (e.g., Part 1 - Basic concepts; Part 11 - laser interferometry; Part 12 - reciprocity; Parts 21/22 - comparison methods) provide complementary methods for vibration and shock transducer calibration. Use ISO 16063-16 when a gravity-based primary calibration is appropriate.