Combines trigger time on vibrating tools into a daily A(8) vibration exposure value, checked against the standard action and limit values — plus the HSE's simpler points-based equivalent.
Read before use: This estimates exposure from the tool vibration magnitude (ahv) and trigger time you enter — real exposure varies with tool condition, accessory, grip force, and technique. Use the manufacturer's declared vibration data or actual measured values where available, and always err toward reducing trigger time when in doubt.
Enter each tool's frequency-weighted vibration magnitude (ahv, in m/s², from the manufacturer's data or a measurement) and the actual trigger time in hours for that tool today.
DAILY EXPOSURE A(8)
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Total trigger time—
Exposure action value2.5 m/s²
Exposure limit value5.0 m/s²
Same inputs as the A(8) tab, expressed as HSE "points" instead — useful when a tool's data sheet quotes points-per-minute directly rather than a raw m/s² figure.
DAILY POINTS
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Total trigger time—
Exposure action value100 points
Exposure limit value400 points
Quick reference
Action & limit values (ISO 5349-1 / EU Physical Agents Directive)
2.5 m/s² A(8) (100 points) — Exposure Action Value: health surveillance, information and training, technical/organisational controls to reduce exposure
5.0 m/s² A(8) (400 points) — Exposure Limit Value: must not normally be exceeded
How the points system works
Points = 2 × ahv² × trigger time (hours), summed across all tools/periods
100 points corresponds exactly to the 2.5 m/s² EAV; 400 points to the 5.0 m/s² ELV
Published by HSE as a simpler way to combine multiple tool exposures without needing square roots — same underlying physics as A(8), just rescaled
Where ahv comes from
Manufacturer's declared vibration emission value, from the tool's data sheet or CE declaration — required by law to be published for most power tools
Declared values are measured under specific test conditions and often underestimate real-world exposure — HSE guidance typically suggests applying a multiplier for real-world use unless better data (e.g. actual measurement) is available
If several accessories are used with one tool (e.g. different drill bits, grinding discs), use the highest relevant value or measure the actual combination in use
Reducing exposure
Rotate tasks between workers to reduce individual trigger time
Select lower-vibration tools or well-maintained equipment — wear and poor maintenance increase vibration
Take regular breaks — a fixed number of long uninterrupted sessions is worse than shorter, spread-out use
Keep hands warm and dry, and avoid gripping tools harder than necessary