What is hand-arm vibration (HAV)?
Hand-arm vibration is vibration transmitted from powered tools and machines into the hands and arms. Long exposure raises the risk of hand-arm vibration syndrome (HAVS), including vibration white finger and nerve damage.
The Control of Vibration at Work Regulations (UK) and EU Directive 2002/44/EC use an 8-hour energy-equivalent value A(8). Enter tool vibration values and trigger times below to compare with the Exposure Action Value and Exposure Limit Value.
Hand-Arm Vibration (HAV) Calculator
HAV · Hand-arm vibration A(8)
Daily exposure from tool vibration values and trigger times. Compare with EAV 2.5 m/s² (100 points) and ELV 5.0 m/s² (400 points).
Formula: A(8) = √(Σ a² × t ÷ 8) · Points ≈ 2 × a² × hours
- Enter trigger time — time the tool vibrates in the hand — not the whole shift.
- EAV 2.5 m/s² ≈ 100 points; ELV 5.0 m/s² ≈ 400 points.
- This tool is for hand-arm vibration only, not whole-body vibration.
- EAV (action value) — A(8) = 2.5 m/s² (100 HSE points)
- ELV (limit value) — A(8) = 5.0 m/s² (400 HSE points)
Formulas
For one tool: A(8) = a × √(t ÷ 8) where a is vibration magnitude (m/s²) and t is exposure time in hours.
For several tools: A(8) = √(Σ aᵢ² × tᵢ ÷ 8)
HSE exposure points (approx.): Points ≈ 2 × a² × hours for each tool, then sum.
Worked examples
- 5 m/s² for 2 hours → A(8) ≈ 2.5 m/s² (≈ 100 points) — at the EAV.
- 10 m/s² for 1 hour → A(8) ≈ 3.54 m/s² — above EAV, below ELV.
- 10 m/s² for 4 hours → A(8) = 5.0 m/s² — at the ELV.
How to read the result
- Below EAV — keep monitoring; maintain low-vibration purchasing and good maintenance.
- At / above EAV — health surveillance, training, job rotation, and lower-vibration tools are expected under UK/EU programmes.
- At / above ELV — daily limit exceeded; reduce exposure before further work that day.
Where to get vibration values
- Manufacturer declared values (check operating condition).
- In-use measurements when declared values are unreliable.
- HSE or industry databases for common tools — still verify against your fleet.
Frequently asked questions
Is trigger time the same as shift length?
No. Use the time the tool is actually vibrating in the hand (trigger time), not the whole shift, unless the tool runs continuously.
Can I add several tools?
Yes. Add a row for each tool and duration. A(8) combines them with the root-sum-square energy formula.
Are points the same as A(8)?
Points are a UK HSE ready-reckoner scale that tracks the same exposure. 100 points ≈ EAV; 400 points ≈ ELV.
Does this cover whole-body vibration?
No. This tool is for hand-arm vibration only. Whole-body vibration (WBV) uses different limits and inputs.
