Vibration exposure · GB · HAV A(8)
Work out daily hand-arm vibration A(8) and exposure points
Combine actual trigger times and representative vibration magnitudes for the tools used during a day.
By HSECalc · Published
Check that this method fits your task
Use frequency-weighted vibration total values in m/s², not a single uncombined axis or a guess from tool power. The result depends on representative inputs and a complete task inventory.
Choose your inputs and work through the steps
- List the vibrating tools and processes actually used that day. Obtain representative frequency-weighted vibration total values for the work.
- Enter actual trigger or exposure time for each tool, not simply the duration of the shift. Include other vibrating activities without overlapping their time.
- Calculate the combined A(8) and points. Keep the unrounded result for comparisons near a boundary.
A(8) = √[Σ(a² × exposure hours) ÷ 8]. Exposure points = 16 × A(8)². GB EAV: 2.5 m/s² / 100 points; ELV: 5 m/s² / 400 points.
A worked example
Illustrative values explain the tool; they are not prescribed inputs for your work.
- 5² × 2 h = 50; 2.5² × 2 h = 12.5.
- A(8) = √((50 + 12.5) ÷ 8) = 2.795 m/s², displayed as 2.80.
- 16 × A(8)² = 125 points: above the GB action value.
Read the result and decide what needs checking
In Great Britain the daily action value is 2.5 m/s² A(8), equivalent to 100 points; the limit is 5 m/s², equivalent to 400 points. At the action value a programme to control exposure is needed; exposure must not exceed the limit.
Review tool choice, maintenance, work methods and exposure duration with the responsible assessor. A lower result does not establish no risk or remove the need for suitable controls.
Common questions
Do I enter the shift length?
Enter actual exposure time for each tool; include all vibrating activities during the day.
Can I use the manufacturer’s number directly?
Check that it represents your actual task and conditions; declared emission figures may not represent workplace exposure.
Is below 100 points risk-free?
No. Lower exposure does not establish no risk; review controls, input quality and individual circumstances.
References and scope notes
- HSE: hand-arm exposure calculator and action/limit values
- HSE L140: vibration measurement and exposure method
Use the current official guidance and the instructions for your actual equipment. HSECalc is independent; a reference is not an endorsement. Read how we use methods and sources or report a correction.