TL-06 · Exposure & health
HAVS exposure points & A(8)
Combine the declared vibration magnitude and trigger time for two tools. The calculation uses trigger time, not shift length.
HAVS reference · points, A(8) and trigger time
How HAVS exposure points and A(8) fit together
This calculator creates one daily record for one person. Add a row whenever the tool, accessory, material, operating mode or other condition gives a materially different vibration magnitude. The calculation adds each row’s exposure contribution; it does not add vibration magnitudes or partial A(8) values directly.
EAV, ELV and the HSE points scale
The Control of Vibration at Work Regulations 2005 sets the hand-arm vibration exposure action value (EAV) at 2.5 m/s² A(8) and the exposure limit value (ELV) at 5 m/s² A(8). On the HSE points scale those values are 100 points and 400 points. Reaching the EAV triggers specified action to reduce risk. The ELV must not be exceeded; 400 points is not a target or an allowance to use up.
Scroll the table sideways to view every column.
| Daily position | Exposure points | A(8) | What the number means |
|---|
| Below EAV | Under 100 | Under 2.5 m/s² | A numerical position below the action value; assessment and reasonably practicable controls still apply. |
| At EAV | 100 | 2.5 m/s² | The daily action value has been reached. |
| Between EAV and ELV | Over 100, under 400 | Over 2.5, under 5 m/s² | Above the action value and below the limit value. |
| At ELV | 400 | 5 m/s² | The daily limit value has been reached. |
| Above ELV | Over 400 | Over 5 m/s² | The entered exposure exceeds the limit value; the tool raises a stop alert and does not present this as permission to continue. |
Formula and multi-tool daily summation
For row i, points are 2 × aᵢ² × Tᵢ, where a is vibration magnitude in m/s² and T is trigger time in hours. Daily points are the sum of those row values. The matching daily exposure is A(8) = √(Σ(aᵢ² × Tᵢ) ÷ 8).
Example: 5 m/s² for 2 hours contributes 100 points. A second exposure of 10 m/s² for 30 minutes contributes another 100 points. The daily total is 200 points and A(8) is 3.536 m/s². Two partial A(8) values of 2.5 m/s² are not added as 5 m/s²; the squared exposure contributions are combined first.
Trigger-time examples
Trigger time is the time the person’s hands are actually exposed to the operating tool, not the shift length, hire period, setup time or a nearby machine’s running time. At a constant 5 m/s², 1 hour gives 50 points, 2 hours gives 100 points and 8 hours gives 400 points. At 10 m/s², 15 minutes gives 50 points, 30 minutes gives 100 points and 2 hours gives 400 points.
Because magnitude is squared, doubling a representative magnitude makes the points accrue four times as quickly. Observe realistic work cycles and include every exposure during the same person’s day rather than relying on a rough “hours on site” estimate.
Input limits and printable record
The tool accepts positive, finite magnitudes and trigger times. It does not decide whether a catalogue value represents the accessory, material, grip, feed force, maintenance condition or operator on the job. It does not apply an uncertainty correction, assess symptoms, select controls or decide health-surveillance duties. Use representative data, retain its source and obtain competent assessment where the input basis or required response is uncertain.
Use Print this record only while the result matches the visible inputs. The print button is withdrawn as soon as a calculation-bearing field changes, a row is added or removed, or required data becomes invalid. A current print includes the job/reference field, printed date, entered rows, points, A(8), assumptions, warning state, formula version and source register.
Sources: HSE L140, Hand-arm vibration guidance on the Regulations; HSE hand-arm vibration exposure calculator guide; The Control of Vibration at Work Regulations 2005. See the full vibration and noise planning guide for input selection, control and escalation context.