Overview
ISO/TS 22704:2022 - Mechanical vibration - Uncertainty of the measurement and evaluation of human exposure to vibration - is a technical specification that provides practical methods to determine the measurement uncertainty associated with assessing human exposure to vibration. It covers both hand‑transmitted (hand–arm) vibration and whole‑body vibration, and applies to workplace exposure assessments, laboratory emission tests of hand‑held or hand‑guided machinery, and vehicle vibration emission testing. The specification clarifies that “uncertainty” here excludes errors caused by poor measurement strategy or misuse of equipment.
Key topics and requirements
- Measurement models and input/output quantities: defines input and output quantities used to calculate measurands and how sensitivity coefficients affect uncertainty.
- Types and sources of uncertainty: treatment of Type A (statistical) and Type B (informed) uncertainties; instrumentation and environmental influence sources are identified.
- Evaluation methods:
- Mathematical modelling of uncertainty (propagation via sensitivity coefficients).
- Interlaboratory comparisons to estimate reproducibility components.
- Estimation from field measurements where laboratory data are not available.
- Statistical treatment: definitions of variance, standard deviation, combined and expanded uncertainty, coverage factor and coverage probability.
- Presentation and use: guidance on how to report uncertainties and use them when comparing measured values or compliance decisions.
- Practical examples: informative annexes provide worked examples for hand–arm exposure (task‑based according to ISO 5349‑2), emission measurements of handheld machines, typical error sources, and statistical background.
Applications and practical value
- Provides a consistent framework for quantifying measurement uncertainty in vibration exposure assessments used in occupational health, product testing, and regulatory compliance.
- Helps test laboratories and measuring bodies evaluate repeatability and reproducibility, support accreditation, and justify measurement results.
- Assists occupational hygienists, safety engineers, and manufacturers in:
- Interpreting exposure measurements with quantified confidence.
- Comparing measured vibration levels against action or limit values with uncertainty taken into account.
- Designing measurement campaigns and selecting instrumentation with known uncertainty contributors.
Who should use this standard
- Test laboratories and measuring personnel performing vibration emission or exposure measurements
- Metrologists and quality managers responsible for uncertainty budgets
- Occupational health and safety professionals and regulators assessing worker exposure
- Manufacturers of hand‑held/hand‑guided machinery and vehicle testing facilities
Related standards
- Normative references include ISO/IEC Guide 99 (VIM) and GUM principles (ISO/IEC Guide 98‑3) for uncertainty concepts. Annex A specifically references ISO 5349‑2 for task‑based hand–arm measurements. Use ISO/TS 22704:2022 in conjunction with applicable exposure and emission standards for complete measurement and compliance procedures.
Keywords: ISO/TS 22704:2022, mechanical vibration, measurement uncertainty, human exposure, hand‑arm vibration, whole‑body vibration, uncertainty evaluation, measurement model.