Understanding hand-arm vibration
What your result means, how the HSE points system works, and practical ways to keep exposure down.
What is HAVS?
Hand-arm vibration syndrome (HAVS) is a condition caused by regular, long-term use of vibrating tools and equipment such as grinders, hammer drills, breakers and chisels. It affects the blood vessels, nerves, muscles and joints of the hand, wrist and arm, and the damage can be permanent.
Early signs
Tingling and numbness in the fingers, which can disturb sleep.
Later signs
Fingers going white then red in the cold or wet, and loss of grip strength.
Action and limit values
The Control of Vibration at Work Regulations 2005 set two levels of daily exposure, measured as A(8): the average vibration over an eight-hour day.
Below the action value
Keep exposure as low as reasonably practicable and keep monitoring.
Exposure action value (EAV)
The employer must reduce exposure as far as reasonably practicable and provide health surveillance.
Exposure limit value (ELV)
Must not be exceeded. Take immediate action to bring exposure down.
How the calculation works
- Exposure points:
points = 2 × a² × T, where a is vibration in m/s² and T is trigger time in hours. - Partial exposure for one tool:
A(8) = a × √(T ÷ 8) - Daily exposure from several tools:
A(8) = √(A₁(8)² + A₂(8)² + …). Points simply add up.
Points ready reckoner
How quickly common vibration levels reach the action and limit values. Use trigger time: the time hands are on the tool while it's running, not the length of the job.
| Vibration (m/s²) | Points per hour | Action value reached after | Limit value reached after |
|---|
Reducing exposure
- Change the work: use methods that avoid vibrating tools, such as hydraulic bursting instead of breaking.
- Choose lower-vibration tools: compare declared vibration values when buying or hiring, and use vibration-reduced versions.
- Limit time: plan the work to cut trigger time and rotate tasks between workers.
- Maintain equipment: keep tools serviced, sharp and balanced, as worn tools vibrate more.
- Keep warm and dry: good circulation helps. Provide gloves and warm clothing in cold conditions.
- Train workers: make sure people know the risks, the early symptoms and how to report them.
Health surveillance
Employers must provide health surveillance for workers likely to be exposed at or above the exposure action value, and for anyone already diagnosed with HAVS. It usually starts with a questionnaire and, where needed, an assessment by an occupational health professional.
Workers should report symptoms early. Catching HAVS early can stop it getting worse.
About this calculator
This calculator follows the HSE hand-arm vibration exposure calculator method. The built-in tool list uses three published sources: HSE initial risk assessment values for stonemasonry tools (Table 1), HSE examples of vibration measured on tools in use (as reproduced by the Canal & River Trust; where a range is given, the upper value is used), and typical values from the EU Good Practice Guide and OPERC wall chart (as reproduced in TG356). These are typical figures: the manufacturer's declared value or an in-use measurement for your own tool is better.
Results are an estimate to help manage risk. They don't replace a suitable vibration risk assessment by a competent person.