Overview
ISO 20643:2005/Amd 1:2012 is an amendment to the international standard governing the evaluation of mechanical vibration emitted by hand-held and hand-guided machinery. This amendment specifically updates the principles related to accelerometer positions for measuring vibration emissions accurately. It is essential for manufacturers, test laboratories, and safety professionals involved in assessing vibration exposure and machinery ergonomics.
Maintained by ISO Technical Committee ISO/TC 118, this amendment refines the methodology for placing accelerometers to ensure consistent, reproducible, and reliable vibration measurements that reflect real-world operating conditions.
Key Topics
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Accelerometer Positioning
Accelerometers should be mounted close to the operator's hand, ideally between the thumb and index finger on the grip surface where the machine is normally held. This ensures measurements are representative of actual human exposure without interfering with grip behavior.
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Measurement Directions
Vibration measurements cover three translational axes (x, y, z) aligned with the tool’s geometry. Simultaneous three-axis measurements are recommended. If not feasible, at least the direction of greatest vibration must be included, with justification if only one or two axes are measured.
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Measurement Locations
When tools have two handgrips, vibration must be simultaneously measured on both hands. Special cases, such as chipping hammers where the operator holds an inserted tool, require declaring vibration above a threshold without direct measurement.
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Vibration Magnitude and Frequency Weighting
The vibration level is quantified by the frequency-weighted root mean square (r.m.s.) acceleration value (m/s²), using specified frequency weighting to align with human response standards.
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Mounting of Transducers
Accelerometers must conform to ISO 8041 requirements, be lightweight relative to the tool, and be firmly attached to prevent measurement errors caused by rotational vibrations or mounting resonance.
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Operating Conditions and Operator Influence
Vibration evaluation must reflect typical working procedures and realistic operating conditions, including the use of vibration-reducing features if available. Skilled operators experienced with the tool must perform the tests to reduce variability.
Applications
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Safety Compliance
Ensures manufacturers meet occupational health and safety standards limiting hand-arm vibration exposure for machinery operators.
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Product Development
Assists engineers in designing tools with reduced vibration emissions, leading to improved user comfort and lower risk of vibration-related injuries.
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Testing and Certification
Provides standardized test method guidelines for laboratories conducting vibration emission testing to verify conformity with relevant safety regulations.
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Ergonomic Assessment
Helps ergonomists assess the vibration load on operators’ hands, contributing to risk assessment and preventive measures against hand-arm vibration syndrome (HAVS).
Related Standards
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ISO 8041 – Human response to vibration – Measuring instrumentation
Specifies instrumentation requirements for vibration measurement referenced in ISO 20643.
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ISO 5349-1 / ISO 5349-2 – Mechanical vibration – Measurement and evaluation of human exposure to hand-transmitted vibration
Complements ISO 20643 with workplace measurement recommendations and guidance on mounting transducers.
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ISO/IEC Directives, Part 2 – Procedures for the technical work of ISO
Governs the drafting and approval of ISO standards, including this amendment.
This amendment to ISO 20643 provides practical, precise guidance on sensor placement and measurement methodology to achieve reliable vibration emission evaluations for powered hand tools. Adhering to these principles supports safer work environments and advances the development of ergonomically optimized machinery.
Open preview (PDF)Mechanical vibration — Hand-held and hand-guided machinery — Principles for evaluation of vibration emission — Amendment 1: Accelerometer positions