HAVS calculator: daily exposure points
Enter each tool's vibration magnitude and trigger time to get the daily exposure in points and m/s² A(8), and how long until the exposure action value (EAV) and limit value (ELV) are reached. Uses HSE's published method.
Daily exposure for one person
Add each tool or process used in the day (up to six). Use the manufacturer's declared vibration value or, better, a measured in-use value. Trigger time is the time the tool is actually vibrating in the hand, not the time on the job.
Need a record per person, every day? In G8 ONE the same calculation is logged against each operative by day, with weekly totals and EAV/ELV warnings. No card needed. 30-day free trial, then choose a plan.
Save it in G8 ONE: start free trialHow the calculation works
This calculator uses the same method as HSE's exposure points system and calculator:
| Measure | Formula | What it means |
|---|---|---|
| Exposure points per tool | points = 2 × a² × T | a is the vibration magnitude in m/s², T is the trigger time in hours |
| Partial exposure | A(8) = a × √(T ÷ 8) | The tool's contribution as an 8-hour equivalent |
| Daily exposure | A(8) = √(A1² + A2² + …) | Partial exposures combine as the square root of the sum of squares; points simply add up |
| Exposure action value | 100 points = 2.5 m/s² A(8) | Above this, reduce exposure as far as reasonably practicable and provide health surveillance |
| Exposure limit value | 400 points = 5 m/s² A(8) | Must not be exceeded in a day |
For example, an SDS drill at 10 m/s² used for 1 hour scores 2 × 10² × 1 = 200 points, and an angle grinder at 5 m/s² for 2 hours scores 2 × 5² × 2 = 100 points. Together that is 300 points, or a daily exposure of √(3.54² + 2.5²) = 4.33 m/s² A(8): above the EAV and below the ELV.
Sources
- HSE: hand-arm vibration exposure calculator guide
- HSE INDG175: Hand-arm vibration at work, a brief guide (PDF)
- HSE L140: Hand-arm vibration, the Control of Vibration at Work Regulations 2005
The result is only as good as the vibration magnitudes and trigger times you enter. Manufacturers' declared values can be lower than real use, so HSE advises using in-use data where you can. This calculator is a planning aid and does not replace a risk assessment.
Questions
What is the HAVS exposure action value?
2.5 m/s² A(8), which is 100 exposure points a day. Above it, employers must put controls in place to reduce exposure and provide health surveillance for those regularly exposed.
What is the exposure limit value?
5 m/s² A(8), or 400 points a day. It must not be exceeded.
How do I get the vibration magnitude for a tool?
From the manufacturer's handbook or tool label, a tool hire company's data, or your own measurements. Use in-use values where you have them.
Can I record HAVS for my whole team?
Yes, in G8 ONE: each operative's tools and trigger times are logged per day with weekly totals and EAV/ELV warnings. See HAVS monitoring software.