Prolonged use of grinders, breakers, impact wrenches and chainsaws transmits vibration that causes Hand-Arm Vibration Syndrome (HAVS) — permanent nerve and circulation damage. Enter the tool’s vibration magnitude and how long you use it to get your daily exposure A(8) and where it falls against the action and limit values.
Exposure values
| A(8) | Meaning | Action |
|---|---|---|
| Below 2.5 m/s² | Below the Exposure Action Value | Good practice still applies |
| 2.5 – 5.0 m/s² | At/above the EAV | Control measures + health surveillance |
| Above 5.0 m/s² | Above the Exposure Limit Value | Must not be exceeded — reduce exposure |
Reduce vibration transfer
FAQ
What is “trigger time”?
The actual hands-on time the tool is vibrating — not the whole shift. A grinder used 15 minutes per hour over 8 hours is 2 hours of trigger time.
How do I lower A(8)?
Lower-vibration tools, job rotation, maintenance (sharp/balanced consumables), and limiting trigger time. Anti-vibration gloves help comfort and warmth but should not be relied on as the primary control.
A(8) = a × √(T/8), per ISO 5349-1. Action/limit values of 2.5 and 5.0 m/s² follow EU Directive 2002/44/EC and are widely used internationally; US programs may instead apply the ACGIH TLV. Use measured, frequency-weighted tool data. Educational estimate, not a substitute for a vibration risk assessment.
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