Overview
ISO/TR 25398:2006 - "Earth‑moving machinery - Guidelines for assessment of exposure to whole‑body vibration of ride‑on machines" - provides practical, evidence‑based guidance for determining, assessing and documenting daily whole‑body vibration (WBV) exposure for operators of ride‑on earth‑moving machinery (as defined in ISO 6165). The Technical Report is informative and intended for employers, national authorities and manufacturers who need to evaluate vibration exposure, comply with health/safety limits and implement vibration‑reduction measures.
Key topics and technical requirements
- Scope and purpose: Guidance on calculating daily vibration exposure A(8) in line with ISO 2631 and EN 14253; does not address shock.
- Harmonized data use: Uses harmonized vibration emission data measured by international institutes, organizations and manufacturers (Annex B) to estimate exposure where workplace measurement is not available.
- Estimation steps:
- Determine vibration magnitude (frequency‑weighted rms acceleration) - Annex B and Clause 4.
- Estimate daily exposure duration (operator contact time with the vibrating seat) - Clause 5.
- Consider measurement and data uncertainties - Clause 6.
- Calculate and assess daily exposure A(8) and/or use a points system for partial and total vibration exposure (Annex C).
- Documentation and forms: Templates and example documentation forms for exposure reporting (Annex D).
- Vibration reduction: Practical guidance to reduce WBV through machine setup, operating practices and terrain management (Annex E) and guidance for measuring vibration reductions resulting from machine improvements (Annex F).
- Definitions and classifications: Terms, operating time, equivalent vibration values and machine‑type operating conditions (Clauses 2–3, Annex A).
Practical applications - who uses it
- Employers and safety managers: estimate operator A(8), decide if exposure action/limit values may be exceeded, and document compliance.
- Manufacturers and designers: evaluate seat/suspension performance, quantify vibration‑reduction features and report harmonized emission values.
- Regulators and occupational health professionals: use standardized methods to assess exposure, interpret results against exposure action/limit values (for example, A(8) = 0.5 m/s² is commonly cited as an action threshold) and guide enforcement.
- Consultants and researchers: apply harmonized datasets when site measurements are impractical and compare results across studies or fleets.
Related standards
- ISO 2631 (evaluation of human exposure to whole‑body vibration)
- ISO 6165 (earth‑moving machinery types)
- ISO 7096 (seat vibration laboratory evaluation)
- EN 14253, EN 474 and EN 500 series
- European Physical Agents (Vibration) Directive 2002/44/EC
ISO/TR 25398:2006 is a practical reference for consistent WBV exposure assessment of ride‑on earth‑moving machines, supporting compliance, risk reduction and documentation using harmonized measurement data.